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-rw-r--r--kernel/bpf/verifier.c20425
1 files changed, 20425 insertions, 0 deletions
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
new file mode 100644
index 0000000000..a7901ed358
--- /dev/null
+++ b/kernel/bpf/verifier.c
@@ -0,0 +1,20425 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/* Copyright (c) 2011-2014 PLUMgrid, http://plumgrid.com
+ * Copyright (c) 2016 Facebook
+ * Copyright (c) 2018 Covalent IO, Inc. http://covalent.io
+ */
+#include <uapi/linux/btf.h>
+#include <linux/bpf-cgroup.h>
+#include <linux/kernel.h>
+#include <linux/types.h>
+#include <linux/slab.h>
+#include <linux/bpf.h>
+#include <linux/btf.h>
+#include <linux/bpf_verifier.h>
+#include <linux/filter.h>
+#include <net/netlink.h>
+#include <linux/file.h>
+#include <linux/vmalloc.h>
+#include <linux/stringify.h>
+#include <linux/bsearch.h>
+#include <linux/sort.h>
+#include <linux/perf_event.h>
+#include <linux/ctype.h>
+#include <linux/error-injection.h>
+#include <linux/bpf_lsm.h>
+#include <linux/btf_ids.h>
+#include <linux/poison.h>
+#include <linux/module.h>
+#include <linux/cpumask.h>
+#include <net/xdp.h>
+
+#include "disasm.h"
+
+static const struct bpf_verifier_ops * const bpf_verifier_ops[] = {
+#define BPF_PROG_TYPE(_id, _name, prog_ctx_type, kern_ctx_type) \
+ [_id] = & _name ## _verifier_ops,
+#define BPF_MAP_TYPE(_id, _ops)
+#define BPF_LINK_TYPE(_id, _name)
+#include <linux/bpf_types.h>
+#undef BPF_PROG_TYPE
+#undef BPF_MAP_TYPE
+#undef BPF_LINK_TYPE
+};
+
+/* bpf_check() is a static code analyzer that walks eBPF program
+ * instruction by instruction and updates register/stack state.
+ * All paths of conditional branches are analyzed until 'bpf_exit' insn.
+ *
+ * The first pass is depth-first-search to check that the program is a DAG.
+ * It rejects the following programs:
+ * - larger than BPF_MAXINSNS insns
+ * - if loop is present (detected via back-edge)
+ * - unreachable insns exist (shouldn't be a forest. program = one function)
+ * - out of bounds or malformed jumps
+ * The second pass is all possible path descent from the 1st insn.
+ * Since it's analyzing all paths through the program, the length of the
+ * analysis is limited to 64k insn, which may be hit even if total number of
+ * insn is less then 4K, but there are too many branches that change stack/regs.
+ * Number of 'branches to be analyzed' is limited to 1k
+ *
+ * On entry to each instruction, each register has a type, and the instruction
+ * changes the types of the registers depending on instruction semantics.
+ * If instruction is BPF_MOV64_REG(BPF_REG_1, BPF_REG_5), then type of R5 is
+ * copied to R1.
+ *
+ * All registers are 64-bit.
+ * R0 - return register
+ * R1-R5 argument passing registers
+ * R6-R9 callee saved registers
+ * R10 - frame pointer read-only
+ *
+ * At the start of BPF program the register R1 contains a pointer to bpf_context
+ * and has type PTR_TO_CTX.
+ *
+ * Verifier tracks arithmetic operations on pointers in case:
+ * BPF_MOV64_REG(BPF_REG_1, BPF_REG_10),
+ * BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, -20),
+ * 1st insn copies R10 (which has FRAME_PTR) type into R1
+ * and 2nd arithmetic instruction is pattern matched to recognize
+ * that it wants to construct a pointer to some element within stack.
+ * So after 2nd insn, the register R1 has type PTR_TO_STACK
+ * (and -20 constant is saved for further stack bounds checking).
+ * Meaning that this reg is a pointer to stack plus known immediate constant.
+ *
+ * Most of the time the registers have SCALAR_VALUE type, which
+ * means the register has some value, but it's not a valid pointer.
+ * (like pointer plus pointer becomes SCALAR_VALUE type)
+ *
+ * When verifier sees load or store instructions the type of base register
+ * can be: PTR_TO_MAP_VALUE, PTR_TO_CTX, PTR_TO_STACK, PTR_TO_SOCKET. These are
+ * four pointer types recognized by check_mem_access() function.
+ *
+ * PTR_TO_MAP_VALUE means that this register is pointing to 'map element value'
+ * and the range of [ptr, ptr + map's value_size) is accessible.
+ *
+ * registers used to pass values to function calls are checked against
+ * function argument constraints.
+ *
+ * ARG_PTR_TO_MAP_KEY is one of such argument constraints.
+ * It means that the register type passed to this function must be
+ * PTR_TO_STACK and it will be used inside the function as
+ * 'pointer to map element key'
+ *
+ * For example the argument constraints for bpf_map_lookup_elem():
+ * .ret_type = RET_PTR_TO_MAP_VALUE_OR_NULL,
+ * .arg1_type = ARG_CONST_MAP_PTR,
+ * .arg2_type = ARG_PTR_TO_MAP_KEY,
+ *
+ * ret_type says that this function returns 'pointer to map elem value or null'
+ * function expects 1st argument to be a const pointer to 'struct bpf_map' and
+ * 2nd argument should be a pointer to stack, which will be used inside
+ * the helper function as a pointer to map element key.
+ *
+ * On the kernel side the helper function looks like:
+ * u64 bpf_map_lookup_elem(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5)
+ * {
+ * struct bpf_map *map = (struct bpf_map *) (unsigned long) r1;
+ * void *key = (void *) (unsigned long) r2;
+ * void *value;
+ *
+ * here kernel can access 'key' and 'map' pointers safely, knowing that
+ * [key, key + map->key_size) bytes are valid and were initialized on
+ * the stack of eBPF program.
+ * }
+ *
+ * Corresponding eBPF program may look like:
+ * BPF_MOV64_REG(BPF_REG_2, BPF_REG_10), // after this insn R2 type is FRAME_PTR
+ * BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -4), // after this insn R2 type is PTR_TO_STACK
+ * BPF_LD_MAP_FD(BPF_REG_1, map_fd), // after this insn R1 type is CONST_PTR_TO_MAP
+ * BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_map_lookup_elem),
+ * here verifier looks at prototype of map_lookup_elem() and sees:
+ * .arg1_type == ARG_CONST_MAP_PTR and R1->type == CONST_PTR_TO_MAP, which is ok,
+ * Now verifier knows that this map has key of R1->map_ptr->key_size bytes
+ *
+ * Then .arg2_type == ARG_PTR_TO_MAP_KEY and R2->type == PTR_TO_STACK, ok so far,
+ * Now verifier checks that [R2, R2 + map's key_size) are within stack limits
+ * and were initialized prior to this call.
+ * If it's ok, then verifier allows this BPF_CALL insn and looks at
+ * .ret_type which is RET_PTR_TO_MAP_VALUE_OR_NULL, so it sets
+ * R0->type = PTR_TO_MAP_VALUE_OR_NULL which means bpf_map_lookup_elem() function
+ * returns either pointer to map value or NULL.
+ *
+ * When type PTR_TO_MAP_VALUE_OR_NULL passes through 'if (reg != 0) goto +off'
+ * insn, the register holding that pointer in the true branch changes state to
+ * PTR_TO_MAP_VALUE and the same register changes state to CONST_IMM in the false
+ * branch. See check_cond_jmp_op().
+ *
+ * After the call R0 is set to return type of the function and registers R1-R5
+ * are set to NOT_INIT to indicate that they are no longer readable.
+ *
+ * The following reference types represent a potential reference to a kernel
+ * resource which, after first being allocated, must be checked and freed by
+ * the BPF program:
+ * - PTR_TO_SOCKET_OR_NULL, PTR_TO_SOCKET
+ *
+ * When the verifier sees a helper call return a reference type, it allocates a
+ * pointer id for the reference and stores it in the current function state.
+ * Similar to the way that PTR_TO_MAP_VALUE_OR_NULL is converted into
+ * PTR_TO_MAP_VALUE, PTR_TO_SOCKET_OR_NULL becomes PTR_TO_SOCKET when the type
+ * passes through a NULL-check conditional. For the branch wherein the state is
+ * changed to CONST_IMM, the verifier releases the reference.
+ *
+ * For each helper function that allocates a reference, such as
+ * bpf_sk_lookup_tcp(), there is a corresponding release function, such as
+ * bpf_sk_release(). When a reference type passes into the release function,
+ * the verifier also releases the reference. If any unchecked or unreleased
+ * reference remains at the end of the program, the verifier rejects it.
+ */
+
+/* verifier_state + insn_idx are pushed to stack when branch is encountered */
+struct bpf_verifier_stack_elem {
+ /* verifer state is 'st'
+ * before processing instruction 'insn_idx'
+ * and after processing instruction 'prev_insn_idx'
+ */
+ struct bpf_verifier_state st;
+ int insn_idx;
+ int prev_insn_idx;
+ struct bpf_verifier_stack_elem *next;
+ /* length of verifier log at the time this state was pushed on stack */
+ u32 log_pos;
+};
+
+#define BPF_COMPLEXITY_LIMIT_JMP_SEQ 8192
+#define BPF_COMPLEXITY_LIMIT_STATES 64
+
+#define BPF_MAP_KEY_POISON (1ULL << 63)
+#define BPF_MAP_KEY_SEEN (1ULL << 62)
+
+#define BPF_MAP_PTR_UNPRIV 1UL
+#define BPF_MAP_PTR_POISON ((void *)((0xeB9FUL << 1) + \
+ POISON_POINTER_DELTA))
+#define BPF_MAP_PTR(X) ((struct bpf_map *)((X) & ~BPF_MAP_PTR_UNPRIV))
+
+static int acquire_reference_state(struct bpf_verifier_env *env, int insn_idx);
+static int release_reference(struct bpf_verifier_env *env, int ref_obj_id);
+static void invalidate_non_owning_refs(struct bpf_verifier_env *env);
+static bool in_rbtree_lock_required_cb(struct bpf_verifier_env *env);
+static int ref_set_non_owning(struct bpf_verifier_env *env,
+ struct bpf_reg_state *reg);
+static void specialize_kfunc(struct bpf_verifier_env *env,
+ u32 func_id, u16 offset, unsigned long *addr);
+static bool is_trusted_reg(const struct bpf_reg_state *reg);
+
+static bool bpf_map_ptr_poisoned(const struct bpf_insn_aux_data *aux)
+{
+ return BPF_MAP_PTR(aux->map_ptr_state) == BPF_MAP_PTR_POISON;
+}
+
+static bool bpf_map_ptr_unpriv(const struct bpf_insn_aux_data *aux)
+{
+ return aux->map_ptr_state & BPF_MAP_PTR_UNPRIV;
+}
+
+static void bpf_map_ptr_store(struct bpf_insn_aux_data *aux,
+ const struct bpf_map *map, bool unpriv)
+{
+ BUILD_BUG_ON((unsigned long)BPF_MAP_PTR_POISON & BPF_MAP_PTR_UNPRIV);
+ unpriv |= bpf_map_ptr_unpriv(aux);
+ aux->map_ptr_state = (unsigned long)map |
+ (unpriv ? BPF_MAP_PTR_UNPRIV : 0UL);
+}
+
+static bool bpf_map_key_poisoned(const struct bpf_insn_aux_data *aux)
+{
+ return aux->map_key_state & BPF_MAP_KEY_POISON;
+}
+
+static bool bpf_map_key_unseen(const struct bpf_insn_aux_data *aux)
+{
+ return !(aux->map_key_state & BPF_MAP_KEY_SEEN);
+}
+
+static u64 bpf_map_key_immediate(const struct bpf_insn_aux_data *aux)
+{
+ return aux->map_key_state & ~(BPF_MAP_KEY_SEEN | BPF_MAP_KEY_POISON);
+}
+
+static void bpf_map_key_store(struct bpf_insn_aux_data *aux, u64 state)
+{
+ bool poisoned = bpf_map_key_poisoned(aux);
+
+ aux->map_key_state = state | BPF_MAP_KEY_SEEN |
+ (poisoned ? BPF_MAP_KEY_POISON : 0ULL);
+}
+
+static bool bpf_helper_call(const struct bpf_insn *insn)
+{
+ return insn->code == (BPF_JMP | BPF_CALL) &&
+ insn->src_reg == 0;
+}
+
+static bool bpf_pseudo_call(const struct bpf_insn *insn)
+{
+ return insn->code == (BPF_JMP | BPF_CALL) &&
+ insn->src_reg == BPF_PSEUDO_CALL;
+}
+
+static bool bpf_pseudo_kfunc_call(const struct bpf_insn *insn)
+{
+ return insn->code == (BPF_JMP | BPF_CALL) &&
+ insn->src_reg == BPF_PSEUDO_KFUNC_CALL;
+}
+
+struct bpf_call_arg_meta {
+ struct bpf_map *map_ptr;
+ bool raw_mode;
+ bool pkt_access;
+ u8 release_regno;
+ int regno;
+ int access_size;
+ int mem_size;
+ u64 msize_max_value;
+ int ref_obj_id;
+ int dynptr_id;
+ int map_uid;
+ int func_id;
+ struct btf *btf;
+ u32 btf_id;
+ struct btf *ret_btf;
+ u32 ret_btf_id;
+ u32 subprogno;
+ struct btf_field *kptr_field;
+};
+
+struct bpf_kfunc_call_arg_meta {
+ /* In parameters */
+ struct btf *btf;
+ u32 func_id;
+ u32 kfunc_flags;
+ const struct btf_type *func_proto;
+ const char *func_name;
+ /* Out parameters */
+ u32 ref_obj_id;
+ u8 release_regno;
+ bool r0_rdonly;
+ u32 ret_btf_id;
+ u64 r0_size;
+ u32 subprogno;
+ struct {
+ u64 value;
+ bool found;
+ } arg_constant;
+
+ /* arg_{btf,btf_id,owning_ref} are used by kfunc-specific handling,
+ * generally to pass info about user-defined local kptr types to later
+ * verification logic
+ * bpf_obj_drop
+ * Record the local kptr type to be drop'd
+ * bpf_refcount_acquire (via KF_ARG_PTR_TO_REFCOUNTED_KPTR arg type)
+ * Record the local kptr type to be refcount_incr'd and use
+ * arg_owning_ref to determine whether refcount_acquire should be
+ * fallible
+ */
+ struct btf *arg_btf;
+ u32 arg_btf_id;
+ bool arg_owning_ref;
+
+ struct {
+ struct btf_field *field;
+ } arg_list_head;
+ struct {
+ struct btf_field *field;
+ } arg_rbtree_root;
+ struct {
+ enum bpf_dynptr_type type;
+ u32 id;
+ u32 ref_obj_id;
+ } initialized_dynptr;
+ struct {
+ u8 spi;
+ u8 frameno;
+ } iter;
+ u64 mem_size;
+};
+
+struct btf *btf_vmlinux;
+
+static DEFINE_MUTEX(bpf_verifier_lock);
+
+static const struct bpf_line_info *
+find_linfo(const struct bpf_verifier_env *env, u32 insn_off)
+{
+ const struct bpf_line_info *linfo;
+ const struct bpf_prog *prog;
+ u32 i, nr_linfo;
+
+ prog = env->prog;
+ nr_linfo = prog->aux->nr_linfo;
+
+ if (!nr_linfo || insn_off >= prog->len)
+ return NULL;
+
+ linfo = prog->aux->linfo;
+ for (i = 1; i < nr_linfo; i++)
+ if (insn_off < linfo[i].insn_off)
+ break;
+
+ return &linfo[i - 1];
+}
+
+__printf(2, 3) static void verbose(void *private_data, const char *fmt, ...)
+{
+ struct bpf_verifier_env *env = private_data;
+ va_list args;
+
+ if (!bpf_verifier_log_needed(&env->log))
+ return;
+
+ va_start(args, fmt);
+ bpf_verifier_vlog(&env->log, fmt, args);
+ va_end(args);
+}
+
+static const char *ltrim(const char *s)
+{
+ while (isspace(*s))
+ s++;
+
+ return s;
+}
+
+__printf(3, 4) static void verbose_linfo(struct bpf_verifier_env *env,
+ u32 insn_off,
+ const char *prefix_fmt, ...)
+{
+ const struct bpf_line_info *linfo;
+
+ if (!bpf_verifier_log_needed(&env->log))
+ return;
+
+ linfo = find_linfo(env, insn_off);
+ if (!linfo || linfo == env->prev_linfo)
+ return;
+
+ if (prefix_fmt) {
+ va_list args;
+
+ va_start(args, prefix_fmt);
+ bpf_verifier_vlog(&env->log, prefix_fmt, args);
+ va_end(args);
+ }
+
+ verbose(env, "%s\n",
+ ltrim(btf_name_by_offset(env->prog->aux->btf,
+ linfo->line_off)));
+
+ env->prev_linfo = linfo;
+}
+
+static void verbose_invalid_scalar(struct bpf_verifier_env *env,
+ struct bpf_reg_state *reg,
+ struct tnum *range, const char *ctx,
+ const char *reg_name)
+{
+ char tn_buf[48];
+
+ verbose(env, "At %s the register %s ", ctx, reg_name);
+ if (!tnum_is_unknown(reg->var_off)) {
+ tnum_strn(tn_buf, sizeof(tn_buf), reg->var_off);
+ verbose(env, "has value %s", tn_buf);
+ } else {
+ verbose(env, "has unknown scalar value");
+ }
+ tnum_strn(tn_buf, sizeof(tn_buf), *range);
+ verbose(env, " should have been in %s\n", tn_buf);
+}
+
+static bool type_is_pkt_pointer(enum bpf_reg_type type)
+{
+ type = base_type(type);
+ return type == PTR_TO_PACKET ||
+ type == PTR_TO_PACKET_META;
+}
+
+static bool type_is_sk_pointer(enum bpf_reg_type type)
+{
+ return type == PTR_TO_SOCKET ||
+ type == PTR_TO_SOCK_COMMON ||
+ type == PTR_TO_TCP_SOCK ||
+ type == PTR_TO_XDP_SOCK;
+}
+
+static bool type_may_be_null(u32 type)
+{
+ return type & PTR_MAYBE_NULL;
+}
+
+static bool reg_not_null(const struct bpf_reg_state *reg)
+{
+ enum bpf_reg_type type;
+
+ type = reg->type;
+ if (type_may_be_null(type))
+ return false;
+
+ type = base_type(type);
+ return type == PTR_TO_SOCKET ||
+ type == PTR_TO_TCP_SOCK ||
+ type == PTR_TO_MAP_VALUE ||
+ type == PTR_TO_MAP_KEY ||
+ type == PTR_TO_SOCK_COMMON ||
+ (type == PTR_TO_BTF_ID && is_trusted_reg(reg)) ||
+ type == PTR_TO_MEM;
+}
+
+static bool type_is_ptr_alloc_obj(u32 type)
+{
+ return base_type(type) == PTR_TO_BTF_ID && type_flag(type) & MEM_ALLOC;
+}
+
+static bool type_is_non_owning_ref(u32 type)
+{
+ return type_is_ptr_alloc_obj(type) && type_flag(type) & NON_OWN_REF;
+}
+
+static struct btf_record *reg_btf_record(const struct bpf_reg_state *reg)
+{
+ struct btf_record *rec = NULL;
+ struct btf_struct_meta *meta;
+
+ if (reg->type == PTR_TO_MAP_VALUE) {
+ rec = reg->map_ptr->record;
+ } else if (type_is_ptr_alloc_obj(reg->type)) {
+ meta = btf_find_struct_meta(reg->btf, reg->btf_id);
+ if (meta)
+ rec = meta->record;
+ }
+ return rec;
+}
+
+static bool subprog_is_global(const struct bpf_verifier_env *env, int subprog)
+{
+ struct bpf_func_info_aux *aux = env->prog->aux->func_info_aux;
+
+ return aux && aux[subprog].linkage == BTF_FUNC_GLOBAL;
+}
+
+static bool reg_may_point_to_spin_lock(const struct bpf_reg_state *reg)
+{
+ return btf_record_has_field(reg_btf_record(reg), BPF_SPIN_LOCK);
+}
+
+static bool type_is_rdonly_mem(u32 type)
+{
+ return type & MEM_RDONLY;
+}
+
+static bool is_acquire_function(enum bpf_func_id func_id,
+ const struct bpf_map *map)
+{
+ enum bpf_map_type map_type = map ? map->map_type : BPF_MAP_TYPE_UNSPEC;
+
+ if (func_id == BPF_FUNC_sk_lookup_tcp ||
+ func_id == BPF_FUNC_sk_lookup_udp ||
+ func_id == BPF_FUNC_skc_lookup_tcp ||
+ func_id == BPF_FUNC_ringbuf_reserve ||
+ func_id == BPF_FUNC_kptr_xchg)
+ return true;
+
+ if (func_id == BPF_FUNC_map_lookup_elem &&
+ (map_type == BPF_MAP_TYPE_SOCKMAP ||
+ map_type == BPF_MAP_TYPE_SOCKHASH))
+ return true;
+
+ return false;
+}
+
+static bool is_ptr_cast_function(enum bpf_func_id func_id)
+{
+ return func_id == BPF_FUNC_tcp_sock ||
+ func_id == BPF_FUNC_sk_fullsock ||
+ func_id == BPF_FUNC_skc_to_tcp_sock ||
+ func_id == BPF_FUNC_skc_to_tcp6_sock ||
+ func_id == BPF_FUNC_skc_to_udp6_sock ||
+ func_id == BPF_FUNC_skc_to_mptcp_sock ||
+ func_id == BPF_FUNC_skc_to_tcp_timewait_sock ||
+ func_id == BPF_FUNC_skc_to_tcp_request_sock;
+}
+
+static bool is_dynptr_ref_function(enum bpf_func_id func_id)
+{
+ return func_id == BPF_FUNC_dynptr_data;
+}
+
+static bool is_sync_callback_calling_kfunc(u32 btf_id);
+
+static bool is_sync_callback_calling_function(enum bpf_func_id func_id)
+{
+ return func_id == BPF_FUNC_for_each_map_elem ||
+ func_id == BPF_FUNC_find_vma ||
+ func_id == BPF_FUNC_loop ||
+ func_id == BPF_FUNC_user_ringbuf_drain;
+}
+
+static bool is_async_callback_calling_function(enum bpf_func_id func_id)
+{
+ return func_id == BPF_FUNC_timer_set_callback;
+}
+
+static bool is_callback_calling_function(enum bpf_func_id func_id)
+{
+ return is_sync_callback_calling_function(func_id) ||
+ is_async_callback_calling_function(func_id);
+}
+
+static bool is_sync_callback_calling_insn(struct bpf_insn *insn)
+{
+ return (bpf_helper_call(insn) && is_sync_callback_calling_function(insn->imm)) ||
+ (bpf_pseudo_kfunc_call(insn) && is_sync_callback_calling_kfunc(insn->imm));
+}
+
+static bool is_storage_get_function(enum bpf_func_id func_id)
+{
+ return func_id == BPF_FUNC_sk_storage_get ||
+ func_id == BPF_FUNC_inode_storage_get ||
+ func_id == BPF_FUNC_task_storage_get ||
+ func_id == BPF_FUNC_cgrp_storage_get;
+}
+
+static bool helper_multiple_ref_obj_use(enum bpf_func_id func_id,
+ const struct bpf_map *map)
+{
+ int ref_obj_uses = 0;
+
+ if (is_ptr_cast_function(func_id))
+ ref_obj_uses++;
+ if (is_acquire_function(func_id, map))
+ ref_obj_uses++;
+ if (is_dynptr_ref_function(func_id))
+ ref_obj_uses++;
+
+ return ref_obj_uses > 1;
+}
+
+static bool is_cmpxchg_insn(const struct bpf_insn *insn)
+{
+ return BPF_CLASS(insn->code) == BPF_STX &&
+ BPF_MODE(insn->code) == BPF_ATOMIC &&
+ insn->imm == BPF_CMPXCHG;
+}
+
+/* string representation of 'enum bpf_reg_type'
+ *
+ * Note that reg_type_str() can not appear more than once in a single verbose()
+ * statement.
+ */
+static const char *reg_type_str(struct bpf_verifier_env *env,
+ enum bpf_reg_type type)
+{
+ char postfix[16] = {0}, prefix[64] = {0};
+ static const char * const str[] = {
+ [NOT_INIT] = "?",
+ [SCALAR_VALUE] = "scalar",
+ [PTR_TO_CTX] = "ctx",
+ [CONST_PTR_TO_MAP] = "map_ptr",
+ [PTR_TO_MAP_VALUE] = "map_value",
+ [PTR_TO_STACK] = "fp",
+ [PTR_TO_PACKET] = "pkt",
+ [PTR_TO_PACKET_META] = "pkt_meta",
+ [PTR_TO_PACKET_END] = "pkt_end",
+ [PTR_TO_FLOW_KEYS] = "flow_keys",
+ [PTR_TO_SOCKET] = "sock",
+ [PTR_TO_SOCK_COMMON] = "sock_common",
+ [PTR_TO_TCP_SOCK] = "tcp_sock",
+ [PTR_TO_TP_BUFFER] = "tp_buffer",
+ [PTR_TO_XDP_SOCK] = "xdp_sock",
+ [PTR_TO_BTF_ID] = "ptr_",
+ [PTR_TO_MEM] = "mem",
+ [PTR_TO_BUF] = "buf",
+ [PTR_TO_FUNC] = "func",
+ [PTR_TO_MAP_KEY] = "map_key",
+ [CONST_PTR_TO_DYNPTR] = "dynptr_ptr",
+ };
+
+ if (type & PTR_MAYBE_NULL) {
+ if (base_type(type) == PTR_TO_BTF_ID)
+ strncpy(postfix, "or_null_", 16);
+ else
+ strncpy(postfix, "_or_null", 16);
+ }
+
+ snprintf(prefix, sizeof(prefix), "%s%s%s%s%s%s%s",
+ type & MEM_RDONLY ? "rdonly_" : "",
+ type & MEM_RINGBUF ? "ringbuf_" : "",
+ type & MEM_USER ? "user_" : "",
+ type & MEM_PERCPU ? "percpu_" : "",
+ type & MEM_RCU ? "rcu_" : "",
+ type & PTR_UNTRUSTED ? "untrusted_" : "",
+ type & PTR_TRUSTED ? "trusted_" : ""
+ );
+
+ snprintf(env->tmp_str_buf, TMP_STR_BUF_LEN, "%s%s%s",
+ prefix, str[base_type(type)], postfix);
+ return env->tmp_str_buf;
+}
+
+static char slot_type_char[] = {
+ [STACK_INVALID] = '?',
+ [STACK_SPILL] = 'r',
+ [STACK_MISC] = 'm',
+ [STACK_ZERO] = '0',
+ [STACK_DYNPTR] = 'd',
+ [STACK_ITER] = 'i',
+};
+
+static void print_liveness(struct bpf_verifier_env *env,
+ enum bpf_reg_liveness live)
+{
+ if (live & (REG_LIVE_READ | REG_LIVE_WRITTEN | REG_LIVE_DONE))
+ verbose(env, "_");
+ if (live & REG_LIVE_READ)
+ verbose(env, "r");
+ if (live & REG_LIVE_WRITTEN)
+ verbose(env, "w");
+ if (live & REG_LIVE_DONE)
+ verbose(env, "D");
+}
+
+static int __get_spi(s32 off)
+{
+ return (-off - 1) / BPF_REG_SIZE;
+}
+
+static struct bpf_func_state *func(struct bpf_verifier_env *env,
+ const struct bpf_reg_state *reg)
+{
+ struct bpf_verifier_state *cur = env->cur_state;
+
+ return cur->frame[reg->frameno];
+}
+
+static bool is_spi_bounds_valid(struct bpf_func_state *state, int spi, int nr_slots)
+{
+ int allocated_slots = state->allocated_stack / BPF_REG_SIZE;
+
+ /* We need to check that slots between [spi - nr_slots + 1, spi] are
+ * within [0, allocated_stack).
+ *
+ * Please note that the spi grows downwards. For example, a dynptr
+ * takes the size of two stack slots; the first slot will be at
+ * spi and the second slot will be at spi - 1.
+ */
+ return spi - nr_slots + 1 >= 0 && spi < allocated_slots;
+}
+
+static int stack_slot_obj_get_spi(struct bpf_verifier_env *env, struct bpf_reg_state *reg,
+ const char *obj_kind, int nr_slots)
+{
+ int off, spi;
+
+ if (!tnum_is_const(reg->var_off)) {
+ verbose(env, "%s has to be at a constant offset\n", obj_kind);
+ return -EINVAL;
+ }
+
+ off = reg->off + reg->var_off.value;
+ if (off % BPF_REG_SIZE) {
+ verbose(env, "cannot pass in %s at an offset=%d\n", obj_kind, off);
+ return -EINVAL;
+ }
+
+ spi = __get_spi(off);
+ if (spi + 1 < nr_slots) {
+ verbose(env, "cannot pass in %s at an offset=%d\n", obj_kind, off);
+ return -EINVAL;
+ }
+
+ if (!is_spi_bounds_valid(func(env, reg), spi, nr_slots))
+ return -ERANGE;
+ return spi;
+}
+
+static int dynptr_get_spi(struct bpf_verifier_env *env, struct bpf_reg_state *reg)
+{
+ return stack_slot_obj_get_spi(env, reg, "dynptr", BPF_DYNPTR_NR_SLOTS);
+}
+
+static int iter_get_spi(struct bpf_verifier_env *env, struct bpf_reg_state *reg, int nr_slots)
+{
+ return stack_slot_obj_get_spi(env, reg, "iter", nr_slots);
+}
+
+static const char *btf_type_name(const struct btf *btf, u32 id)
+{
+ return btf_name_by_offset(btf, btf_type_by_id(btf, id)->name_off);
+}
+
+static const char *dynptr_type_str(enum bpf_dynptr_type type)
+{
+ switch (type) {
+ case BPF_DYNPTR_TYPE_LOCAL:
+ return "local";
+ case BPF_DYNPTR_TYPE_RINGBUF:
+ return "ringbuf";
+ case BPF_DYNPTR_TYPE_SKB:
+ return "skb";
+ case BPF_DYNPTR_TYPE_XDP:
+ return "xdp";
+ case BPF_DYNPTR_TYPE_INVALID:
+ return "<invalid>";
+ default:
+ WARN_ONCE(1, "unknown dynptr type %d\n", type);
+ return "<unknown>";
+ }
+}
+
+static const char *iter_type_str(const struct btf *btf, u32 btf_id)
+{
+ if (!btf || btf_id == 0)
+ return "<invalid>";
+
+ /* we already validated that type is valid and has conforming name */
+ return btf_type_name(btf, btf_id) + sizeof(ITER_PREFIX) - 1;
+}
+
+static const char *iter_state_str(enum bpf_iter_state state)
+{
+ switch (state) {
+ case BPF_ITER_STATE_ACTIVE:
+ return "active";
+ case BPF_ITER_STATE_DRAINED:
+ return "drained";
+ case BPF_ITER_STATE_INVALID:
+ return "<invalid>";
+ default:
+ WARN_ONCE(1, "unknown iter state %d\n", state);
+ return "<unknown>";
+ }
+}
+
+static void mark_reg_scratched(struct bpf_verifier_env *env, u32 regno)
+{
+ env->scratched_regs |= 1U << regno;
+}
+
+static void mark_stack_slot_scratched(struct bpf_verifier_env *env, u32 spi)
+{
+ env->scratched_stack_slots |= 1ULL << spi;
+}
+
+static bool reg_scratched(const struct bpf_verifier_env *env, u32 regno)
+{
+ return (env->scratched_regs >> regno) & 1;
+}
+
+static bool stack_slot_scratched(const struct bpf_verifier_env *env, u64 regno)
+{
+ return (env->scratched_stack_slots >> regno) & 1;
+}
+
+static bool verifier_state_scratched(const struct bpf_verifier_env *env)
+{
+ return env->scratched_regs || env->scratched_stack_slots;
+}
+
+static void mark_verifier_state_clean(struct bpf_verifier_env *env)
+{
+ env->scratched_regs = 0U;
+ env->scratched_stack_slots = 0ULL;
+}
+
+/* Used for printing the entire verifier state. */
+static void mark_verifier_state_scratched(struct bpf_verifier_env *env)
+{
+ env->scratched_regs = ~0U;
+ env->scratched_stack_slots = ~0ULL;
+}
+
+static enum bpf_dynptr_type arg_to_dynptr_type(enum bpf_arg_type arg_type)
+{
+ switch (arg_type & DYNPTR_TYPE_FLAG_MASK) {
+ case DYNPTR_TYPE_LOCAL:
+ return BPF_DYNPTR_TYPE_LOCAL;
+ case DYNPTR_TYPE_RINGBUF:
+ return BPF_DYNPTR_TYPE_RINGBUF;
+ case DYNPTR_TYPE_SKB:
+ return BPF_DYNPTR_TYPE_SKB;
+ case DYNPTR_TYPE_XDP:
+ return BPF_DYNPTR_TYPE_XDP;
+ default:
+ return BPF_DYNPTR_TYPE_INVALID;
+ }
+}
+
+static enum bpf_type_flag get_dynptr_type_flag(enum bpf_dynptr_type type)
+{
+ switch (type) {
+ case BPF_DYNPTR_TYPE_LOCAL:
+ return DYNPTR_TYPE_LOCAL;
+ case BPF_DYNPTR_TYPE_RINGBUF:
+ return DYNPTR_TYPE_RINGBUF;
+ case BPF_DYNPTR_TYPE_SKB:
+ return DYNPTR_TYPE_SKB;
+ case BPF_DYNPTR_TYPE_XDP:
+ return DYNPTR_TYPE_XDP;
+ default:
+ return 0;
+ }
+}
+
+static bool dynptr_type_refcounted(enum bpf_dynptr_type type)
+{
+ return type == BPF_DYNPTR_TYPE_RINGBUF;
+}
+
+static void __mark_dynptr_reg(struct bpf_reg_state *reg,
+ enum bpf_dynptr_type type,
+ bool first_slot, int dynptr_id);
+
+static void __mark_reg_not_init(const struct bpf_verifier_env *env,
+ struct bpf_reg_state *reg);
+
+static void mark_dynptr_stack_regs(struct bpf_verifier_env *env,
+ struct bpf_reg_state *sreg1,
+ struct bpf_reg_state *sreg2,
+ enum bpf_dynptr_type type)
+{
+ int id = ++env->id_gen;
+
+ __mark_dynptr_reg(sreg1, type, true, id);
+ __mark_dynptr_reg(sreg2, type, false, id);
+}
+
+static void mark_dynptr_cb_reg(struct bpf_verifier_env *env,
+ struct bpf_reg_state *reg,
+ enum bpf_dynptr_type type)
+{
+ __mark_dynptr_reg(reg, type, true, ++env->id_gen);
+}
+
+static int destroy_if_dynptr_stack_slot(struct bpf_verifier_env *env,
+ struct bpf_func_state *state, int spi);
+
+static int mark_stack_slots_dynptr(struct bpf_verifier_env *env, struct bpf_reg_state *reg,
+ enum bpf_arg_type arg_type, int insn_idx, int clone_ref_obj_id)
+{
+ struct bpf_func_state *state = func(env, reg);
+ enum bpf_dynptr_type type;
+ int spi, i, err;
+
+ spi = dynptr_get_spi(env, reg);
+ if (spi < 0)
+ return spi;
+
+ /* We cannot assume both spi and spi - 1 belong to the same dynptr,
+ * hence we need to call destroy_if_dynptr_stack_slot twice for both,
+ * to ensure that for the following example:
+ * [d1][d1][d2][d2]
+ * spi 3 2 1 0
+ * So marking spi = 2 should lead to destruction of both d1 and d2. In
+ * case they do belong to same dynptr, second call won't see slot_type
+ * as STACK_DYNPTR and will simply skip destruction.
+ */
+ err = destroy_if_dynptr_stack_slot(env, state, spi);
+ if (err)
+ return err;
+ err = destroy_if_dynptr_stack_slot(env, state, spi - 1);
+ if (err)
+ return err;
+
+ for (i = 0; i < BPF_REG_SIZE; i++) {
+ state->stack[spi].slot_type[i] = STACK_DYNPTR;
+ state->stack[spi - 1].slot_type[i] = STACK_DYNPTR;
+ }
+
+ type = arg_to_dynptr_type(arg_type);
+ if (type == BPF_DYNPTR_TYPE_INVALID)
+ return -EINVAL;
+
+ mark_dynptr_stack_regs(env, &state->stack[spi].spilled_ptr,
+ &state->stack[spi - 1].spilled_ptr, type);
+
+ if (dynptr_type_refcounted(type)) {
+ /* The id is used to track proper releasing */
+ int id;
+
+ if (clone_ref_obj_id)
+ id = clone_ref_obj_id;
+ else
+ id = acquire_reference_state(env, insn_idx);
+
+ if (id < 0)
+ return id;
+
+ state->stack[spi].spilled_ptr.ref_obj_id = id;
+ state->stack[spi - 1].spilled_ptr.ref_obj_id = id;
+ }
+
+ state->stack[spi].spilled_ptr.live |= REG_LIVE_WRITTEN;
+ state->stack[spi - 1].spilled_ptr.live |= REG_LIVE_WRITTEN;
+
+ return 0;
+}
+
+static void invalidate_dynptr(struct bpf_verifier_env *env, struct bpf_func_state *state, int spi)
+{
+ int i;
+
+ for (i = 0; i < BPF_REG_SIZE; i++) {
+ state->stack[spi].slot_type[i] = STACK_INVALID;
+ state->stack[spi - 1].slot_type[i] = STACK_INVALID;
+ }
+
+ __mark_reg_not_init(env, &state->stack[spi].spilled_ptr);
+ __mark_reg_not_init(env, &state->stack[spi - 1].spilled_ptr);
+
+ /* Why do we need to set REG_LIVE_WRITTEN for STACK_INVALID slot?
+ *
+ * While we don't allow reading STACK_INVALID, it is still possible to
+ * do <8 byte writes marking some but not all slots as STACK_MISC. Then,
+ * helpers or insns can do partial read of that part without failing,
+ * but check_stack_range_initialized, check_stack_read_var_off, and
+ * check_stack_read_fixed_off will do mark_reg_read for all 8-bytes of
+ * the slot conservatively. Hence we need to prevent those liveness
+ * marking walks.
+ *
+ * This was not a problem before because STACK_INVALID is only set by
+ * default (where the default reg state has its reg->parent as NULL), or
+ * in clean_live_states after REG_LIVE_DONE (at which point
+ * mark_reg_read won't walk reg->parent chain), but not randomly during
+ * verifier state exploration (like we did above). Hence, for our case
+ * parentage chain will still be live (i.e. reg->parent may be
+ * non-NULL), while earlier reg->parent was NULL, so we need
+ * REG_LIVE_WRITTEN to screen off read marker propagation when it is
+ * done later on reads or by mark_dynptr_read as well to unnecessary
+ * mark registers in verifier state.
+ */
+ state->stack[spi].spilled_ptr.live |= REG_LIVE_WRITTEN;
+ state->stack[spi - 1].spilled_ptr.live |= REG_LIVE_WRITTEN;
+}
+
+static int unmark_stack_slots_dynptr(struct bpf_verifier_env *env, struct bpf_reg_state *reg)
+{
+ struct bpf_func_state *state = func(env, reg);
+ int spi, ref_obj_id, i;
+
+ spi = dynptr_get_spi(env, reg);
+ if (spi < 0)
+ return spi;
+
+ if (!dynptr_type_refcounted(state->stack[spi].spilled_ptr.dynptr.type)) {
+ invalidate_dynptr(env, state, spi);
+ return 0;
+ }
+
+ ref_obj_id = state->stack[spi].spilled_ptr.ref_obj_id;
+
+ /* If the dynptr has a ref_obj_id, then we need to invalidate
+ * two things:
+ *
+ * 1) Any dynptrs with a matching ref_obj_id (clones)
+ * 2) Any slices derived from this dynptr.
+ */
+
+ /* Invalidate any slices associated with this dynptr */
+ WARN_ON_ONCE(release_reference(env, ref_obj_id));
+
+ /* Invalidate any dynptr clones */
+ for (i = 1; i < state->allocated_stack / BPF_REG_SIZE; i++) {
+ if (state->stack[i].spilled_ptr.ref_obj_id != ref_obj_id)
+ continue;
+
+ /* it should always be the case that if the ref obj id
+ * matches then the stack slot also belongs to a
+ * dynptr
+ */
+ if (state->stack[i].slot_type[0] != STACK_DYNPTR) {
+ verbose(env, "verifier internal error: misconfigured ref_obj_id\n");
+ return -EFAULT;
+ }
+ if (state->stack[i].spilled_ptr.dynptr.first_slot)
+ invalidate_dynptr(env, state, i);
+ }
+
+ return 0;
+}
+
+static void __mark_reg_unknown(const struct bpf_verifier_env *env,
+ struct bpf_reg_state *reg);
+
+static void mark_reg_invalid(const struct bpf_verifier_env *env, struct bpf_reg_state *reg)
+{
+ if (!env->allow_ptr_leaks)
+ __mark_reg_not_init(env, reg);
+ else
+ __mark_reg_unknown(env, reg);
+}
+
+static int destroy_if_dynptr_stack_slot(struct bpf_verifier_env *env,
+ struct bpf_func_state *state, int spi)
+{
+ struct bpf_func_state *fstate;
+ struct bpf_reg_state *dreg;
+ int i, dynptr_id;
+
+ /* We always ensure that STACK_DYNPTR is never set partially,
+ * hence just checking for slot_type[0] is enough. This is
+ * different for STACK_SPILL, where it may be only set for
+ * 1 byte, so code has to use is_spilled_reg.
+ */
+ if (state->stack[spi].slot_type[0] != STACK_DYNPTR)
+ return 0;
+
+ /* Reposition spi to first slot */
+ if (!state->stack[spi].spilled_ptr.dynptr.first_slot)
+ spi = spi + 1;
+
+ if (dynptr_type_refcounted(state->stack[spi].spilled_ptr.dynptr.type)) {
+ verbose(env, "cannot overwrite referenced dynptr\n");
+ return -EINVAL;
+ }
+
+ mark_stack_slot_scratched(env, spi);
+ mark_stack_slot_scratched(env, spi - 1);
+
+ /* Writing partially to one dynptr stack slot destroys both. */
+ for (i = 0; i < BPF_REG_SIZE; i++) {
+ state->stack[spi].slot_type[i] = STACK_INVALID;
+ state->stack[spi - 1].slot_type[i] = STACK_INVALID;
+ }
+
+ dynptr_id = state->stack[spi].spilled_ptr.id;
+ /* Invalidate any slices associated with this dynptr */
+ bpf_for_each_reg_in_vstate(env->cur_state, fstate, dreg, ({
+ /* Dynptr slices are only PTR_TO_MEM_OR_NULL and PTR_TO_MEM */
+ if (dreg->type != (PTR_TO_MEM | PTR_MAYBE_NULL) && dreg->type != PTR_TO_MEM)
+ continue;
+ if (dreg->dynptr_id == dynptr_id)
+ mark_reg_invalid(env, dreg);
+ }));
+
+ /* Do not release reference state, we are destroying dynptr on stack,
+ * not using some helper to release it. Just reset register.
+ */
+ __mark_reg_not_init(env, &state->stack[spi].spilled_ptr);
+ __mark_reg_not_init(env, &state->stack[spi - 1].spilled_ptr);
+
+ /* Same reason as unmark_stack_slots_dynptr above */
+ state->stack[spi].spilled_ptr.live |= REG_LIVE_WRITTEN;
+ state->stack[spi - 1].spilled_ptr.live |= REG_LIVE_WRITTEN;
+
+ return 0;
+}
+
+static bool is_dynptr_reg_valid_uninit(struct bpf_verifier_env *env, struct bpf_reg_state *reg)
+{
+ int spi;
+
+ if (reg->type == CONST_PTR_TO_DYNPTR)
+ return false;
+
+ spi = dynptr_get_spi(env, reg);
+
+ /* -ERANGE (i.e. spi not falling into allocated stack slots) isn't an
+ * error because this just means the stack state hasn't been updated yet.
+ * We will do check_mem_access to check and update stack bounds later.
+ */
+ if (spi < 0 && spi != -ERANGE)
+ return false;
+
+ /* We don't need to check if the stack slots are marked by previous
+ * dynptr initializations because we allow overwriting existing unreferenced
+ * STACK_DYNPTR slots, see mark_stack_slots_dynptr which calls
+ * destroy_if_dynptr_stack_slot to ensure dynptr objects at the slots we are
+ * touching are completely destructed before we reinitialize them for a new
+ * one. For referenced ones, destroy_if_dynptr_stack_slot returns an error early
+ * instead of delaying it until the end where the user will get "Unreleased
+ * reference" error.
+ */
+ return true;
+}
+
+static bool is_dynptr_reg_valid_init(struct bpf_verifier_env *env, struct bpf_reg_state *reg)
+{
+ struct bpf_func_state *state = func(env, reg);
+ int i, spi;
+
+ /* This already represents first slot of initialized bpf_dynptr.
+ *
+ * CONST_PTR_TO_DYNPTR already has fixed and var_off as 0 due to
+ * check_func_arg_reg_off's logic, so we don't need to check its
+ * offset and alignment.
+ */
+ if (reg->type == CONST_PTR_TO_DYNPTR)
+ return true;
+
+ spi = dynptr_get_spi(env, reg);
+ if (spi < 0)
+ return false;
+ if (!state->stack[spi].spilled_ptr.dynptr.first_slot)
+ return false;
+
+ for (i = 0; i < BPF_REG_SIZE; i++) {
+ if (state->stack[spi].slot_type[i] != STACK_DYNPTR ||
+ state->stack[spi - 1].slot_type[i] != STACK_DYNPTR)
+ return false;
+ }
+
+ return true;
+}
+
+static bool is_dynptr_type_expected(struct bpf_verifier_env *env, struct bpf_reg_state *reg,
+ enum bpf_arg_type arg_type)
+{
+ struct bpf_func_state *state = func(env, reg);
+ enum bpf_dynptr_type dynptr_type;
+ int spi;
+
+ /* ARG_PTR_TO_DYNPTR takes any type of dynptr */
+ if (arg_type == ARG_PTR_TO_DYNPTR)
+ return true;
+
+ dynptr_type = arg_to_dynptr_type(arg_type);
+ if (reg->type == CONST_PTR_TO_DYNPTR) {
+ return reg->dynptr.type == dynptr_type;
+ } else {
+ spi = dynptr_get_spi(env, reg);
+ if (spi < 0)
+ return false;
+ return state->stack[spi].spilled_ptr.dynptr.type == dynptr_type;
+ }
+}
+
+static void __mark_reg_known_zero(struct bpf_reg_state *reg);
+
+static int mark_stack_slots_iter(struct bpf_verifier_env *env,
+ struct bpf_reg_state *reg, int insn_idx,
+ struct btf *btf, u32 btf_id, int nr_slots)
+{
+ struct bpf_func_state *state = func(env, reg);
+ int spi, i, j, id;
+
+ spi = iter_get_spi(env, reg, nr_slots);
+ if (spi < 0)
+ return spi;
+
+ id = acquire_reference_state(env, insn_idx);
+ if (id < 0)
+ return id;
+
+ for (i = 0; i < nr_slots; i++) {
+ struct bpf_stack_state *slot = &state->stack[spi - i];
+ struct bpf_reg_state *st = &slot->spilled_ptr;
+
+ __mark_reg_known_zero(st);
+ st->type = PTR_TO_STACK; /* we don't have dedicated reg type */
+ st->live |= REG_LIVE_WRITTEN;
+ st->ref_obj_id = i == 0 ? id : 0;
+ st->iter.btf = btf;
+ st->iter.btf_id = btf_id;
+ st->iter.state = BPF_ITER_STATE_ACTIVE;
+ st->iter.depth = 0;
+
+ for (j = 0; j < BPF_REG_SIZE; j++)
+ slot->slot_type[j] = STACK_ITER;
+
+ mark_stack_slot_scratched(env, spi - i);
+ }
+
+ return 0;
+}
+
+static int unmark_stack_slots_iter(struct bpf_verifier_env *env,
+ struct bpf_reg_state *reg, int nr_slots)
+{
+ struct bpf_func_state *state = func(env, reg);
+ int spi, i, j;
+
+ spi = iter_get_spi(env, reg, nr_slots);
+ if (spi < 0)
+ return spi;
+
+ for (i = 0; i < nr_slots; i++) {
+ struct bpf_stack_state *slot = &state->stack[spi - i];
+ struct bpf_reg_state *st = &slot->spilled_ptr;
+
+ if (i == 0)
+ WARN_ON_ONCE(release_reference(env, st->ref_obj_id));
+
+ __mark_reg_not_init(env, st);
+
+ /* see unmark_stack_slots_dynptr() for why we need to set REG_LIVE_WRITTEN */
+ st->live |= REG_LIVE_WRITTEN;
+
+ for (j = 0; j < BPF_REG_SIZE; j++)
+ slot->slot_type[j] = STACK_INVALID;
+
+ mark_stack_slot_scratched(env, spi - i);
+ }
+
+ return 0;
+}
+
+static bool is_iter_reg_valid_uninit(struct bpf_verifier_env *env,
+ struct bpf_reg_state *reg, int nr_slots)
+{
+ struct bpf_func_state *state = func(env, reg);
+ int spi, i, j;
+
+ /* For -ERANGE (i.e. spi not falling into allocated stack slots), we
+ * will do check_mem_access to check and update stack bounds later, so
+ * return true for that case.
+ */
+ spi = iter_get_spi(env, reg, nr_slots);
+ if (spi == -ERANGE)
+ return true;
+ if (spi < 0)
+ return false;
+
+ for (i = 0; i < nr_slots; i++) {
+ struct bpf_stack_state *slot = &state->stack[spi - i];
+
+ for (j = 0; j < BPF_REG_SIZE; j++)
+ if (slot->slot_type[j] == STACK_ITER)
+ return false;
+ }
+
+ return true;
+}
+
+static bool is_iter_reg_valid_init(struct bpf_verifier_env *env, struct bpf_reg_state *reg,
+ struct btf *btf, u32 btf_id, int nr_slots)
+{
+ struct bpf_func_state *state = func(env, reg);
+ int spi, i, j;
+
+ spi = iter_get_spi(env, reg, nr_slots);
+ if (spi < 0)
+ return false;
+
+ for (i = 0; i < nr_slots; i++) {
+ struct bpf_stack_state *slot = &state->stack[spi - i];
+ struct bpf_reg_state *st = &slot->spilled_ptr;
+
+ /* only main (first) slot has ref_obj_id set */
+ if (i == 0 && !st->ref_obj_id)
+ return false;
+ if (i != 0 && st->ref_obj_id)
+ return false;
+ if (st->iter.btf != btf || st->iter.btf_id != btf_id)
+ return false;
+
+ for (j = 0; j < BPF_REG_SIZE; j++)
+ if (slot->slot_type[j] != STACK_ITER)
+ return false;
+ }
+
+ return true;
+}
+
+/* Check if given stack slot is "special":
+ * - spilled register state (STACK_SPILL);
+ * - dynptr state (STACK_DYNPTR);
+ * - iter state (STACK_ITER).
+ */
+static bool is_stack_slot_special(const struct bpf_stack_state *stack)
+{
+ enum bpf_stack_slot_type type = stack->slot_type[BPF_REG_SIZE - 1];
+
+ switch (type) {
+ case STACK_SPILL:
+ case STACK_DYNPTR:
+ case STACK_ITER:
+ return true;
+ case STACK_INVALID:
+ case STACK_MISC:
+ case STACK_ZERO:
+ return false;
+ default:
+ WARN_ONCE(1, "unknown stack slot type %d\n", type);
+ return true;
+ }
+}
+
+/* The reg state of a pointer or a bounded scalar was saved when
+ * it was spilled to the stack.
+ */
+static bool is_spilled_reg(const struct bpf_stack_state *stack)
+{
+ return stack->slot_type[BPF_REG_SIZE - 1] == STACK_SPILL;
+}
+
+static bool is_spilled_scalar_reg(const struct bpf_stack_state *stack)
+{
+ return stack->slot_type[BPF_REG_SIZE - 1] == STACK_SPILL &&
+ stack->spilled_ptr.type == SCALAR_VALUE;
+}
+
+static void scrub_spilled_slot(u8 *stype)
+{
+ if (*stype != STACK_INVALID)
+ *stype = STACK_MISC;
+}
+
+static void print_verifier_state(struct bpf_verifier_env *env,
+ const struct bpf_func_state *state,
+ bool print_all)
+{
+ const struct bpf_reg_state *reg;
+ enum bpf_reg_type t;
+ int i;
+
+ if (state->frameno)
+ verbose(env, " frame%d:", state->frameno);
+ for (i = 0; i < MAX_BPF_REG; i++) {
+ reg = &state->regs[i];
+ t = reg->type;
+ if (t == NOT_INIT)
+ continue;
+ if (!print_all && !reg_scratched(env, i))
+ continue;
+ verbose(env, " R%d", i);
+ print_liveness(env, reg->live);
+ verbose(env, "=");
+ if (t == SCALAR_VALUE && reg->precise)
+ verbose(env, "P");
+ if ((t == SCALAR_VALUE || t == PTR_TO_STACK) &&
+ tnum_is_const(reg->var_off)) {
+ /* reg->off should be 0 for SCALAR_VALUE */
+ verbose(env, "%s", t == SCALAR_VALUE ? "" : reg_type_str(env, t));
+ verbose(env, "%lld", reg->var_off.value + reg->off);
+ } else {
+ const char *sep = "";
+
+ verbose(env, "%s", reg_type_str(env, t));
+ if (base_type(t) == PTR_TO_BTF_ID)
+ verbose(env, "%s", btf_type_name(reg->btf, reg->btf_id));
+ verbose(env, "(");
+/*
+ * _a stands for append, was shortened to avoid multiline statements below.
+ * This macro is used to output a comma separated list of attributes.
+ */
+#define verbose_a(fmt, ...) ({ verbose(env, "%s" fmt, sep, __VA_ARGS__); sep = ","; })
+
+ if (reg->id)
+ verbose_a("id=%d", reg->id);
+ if (reg->ref_obj_id)
+ verbose_a("ref_obj_id=%d", reg->ref_obj_id);
+ if (type_is_non_owning_ref(reg->type))
+ verbose_a("%s", "non_own_ref");
+ if (t != SCALAR_VALUE)
+ verbose_a("off=%d", reg->off);
+ if (type_is_pkt_pointer(t))
+ verbose_a("r=%d", reg->range);
+ else if (base_type(t) == CONST_PTR_TO_MAP ||
+ base_type(t) == PTR_TO_MAP_KEY ||
+ base_type(t) == PTR_TO_MAP_VALUE)
+ verbose_a("ks=%d,vs=%d",
+ reg->map_ptr->key_size,
+ reg->map_ptr->value_size);
+ if (tnum_is_const(reg->var_off)) {
+ /* Typically an immediate SCALAR_VALUE, but
+ * could be a pointer whose offset is too big
+ * for reg->off
+ */
+ verbose_a("imm=%llx", reg->var_off.value);
+ } else {
+ if (reg->smin_value != reg->umin_value &&
+ reg->smin_value != S64_MIN)
+ verbose_a("smin=%lld", (long long)reg->smin_value);
+ if (reg->smax_value != reg->umax_value &&
+ reg->smax_value != S64_MAX)
+ verbose_a("smax=%lld", (long long)reg->smax_value);
+ if (reg->umin_value != 0)
+ verbose_a("umin=%llu", (unsigned long long)reg->umin_value);
+ if (reg->umax_value != U64_MAX)
+ verbose_a("umax=%llu", (unsigned long long)reg->umax_value);
+ if (!tnum_is_unknown(reg->var_off)) {
+ char tn_buf[48];
+
+ tnum_strn(tn_buf, sizeof(tn_buf), reg->var_off);
+ verbose_a("var_off=%s", tn_buf);
+ }
+ if (reg->s32_min_value != reg->smin_value &&
+ reg->s32_min_value != S32_MIN)
+ verbose_a("s32_min=%d", (int)(reg->s32_min_value));
+ if (reg->s32_max_value != reg->smax_value &&
+ reg->s32_max_value != S32_MAX)
+ verbose_a("s32_max=%d", (int)(reg->s32_max_value));
+ if (reg->u32_min_value != reg->umin_value &&
+ reg->u32_min_value != U32_MIN)
+ verbose_a("u32_min=%d", (int)(reg->u32_min_value));
+ if (reg->u32_max_value != reg->umax_value &&
+ reg->u32_max_value != U32_MAX)
+ verbose_a("u32_max=%d", (int)(reg->u32_max_value));
+ }
+#undef verbose_a
+
+ verbose(env, ")");
+ }
+ }
+ for (i = 0; i < state->allocated_stack / BPF_REG_SIZE; i++) {
+ char types_buf[BPF_REG_SIZE + 1];
+ bool valid = false;
+ int j;
+
+ for (j = 0; j < BPF_REG_SIZE; j++) {
+ if (state->stack[i].slot_type[j] != STACK_INVALID)
+ valid = true;
+ types_buf[j] = slot_type_char[state->stack[i].slot_type[j]];
+ }
+ types_buf[BPF_REG_SIZE] = 0;
+ if (!valid)
+ continue;
+ if (!print_all && !stack_slot_scratched(env, i))
+ continue;
+ switch (state->stack[i].slot_type[BPF_REG_SIZE - 1]) {
+ case STACK_SPILL:
+ reg = &state->stack[i].spilled_ptr;
+ t = reg->type;
+
+ verbose(env, " fp%d", (-i - 1) * BPF_REG_SIZE);
+ print_liveness(env, reg->live);
+ verbose(env, "=%s", t == SCALAR_VALUE ? "" : reg_type_str(env, t));
+ if (t == SCALAR_VALUE && reg->precise)
+ verbose(env, "P");
+ if (t == SCALAR_VALUE && tnum_is_const(reg->var_off))
+ verbose(env, "%lld", reg->var_off.value + reg->off);
+ break;
+ case STACK_DYNPTR:
+ i += BPF_DYNPTR_NR_SLOTS - 1;
+ reg = &state->stack[i].spilled_ptr;
+
+ verbose(env, " fp%d", (-i - 1) * BPF_REG_SIZE);
+ print_liveness(env, reg->live);
+ verbose(env, "=dynptr_%s", dynptr_type_str(reg->dynptr.type));
+ if (reg->ref_obj_id)
+ verbose(env, "(ref_id=%d)", reg->ref_obj_id);
+ break;
+ case STACK_ITER:
+ /* only main slot has ref_obj_id set; skip others */
+ reg = &state->stack[i].spilled_ptr;
+ if (!reg->ref_obj_id)
+ continue;
+
+ verbose(env, " fp%d", (-i - 1) * BPF_REG_SIZE);
+ print_liveness(env, reg->live);
+ verbose(env, "=iter_%s(ref_id=%d,state=%s,depth=%u)",
+ iter_type_str(reg->iter.btf, reg->iter.btf_id),
+ reg->ref_obj_id, iter_state_str(reg->iter.state),
+ reg->iter.depth);
+ break;
+ case STACK_MISC:
+ case STACK_ZERO:
+ default:
+ reg = &state->stack[i].spilled_ptr;
+
+ for (j = 0; j < BPF_REG_SIZE; j++)
+ types_buf[j] = slot_type_char[state->stack[i].slot_type[j]];
+ types_buf[BPF_REG_SIZE] = 0;
+
+ verbose(env, " fp%d", (-i - 1) * BPF_REG_SIZE);
+ print_liveness(env, reg->live);
+ verbose(env, "=%s", types_buf);
+ break;
+ }
+ }
+ if (state->acquired_refs && state->refs[0].id) {
+ verbose(env, " refs=%d", state->refs[0].id);
+ for (i = 1; i < state->acquired_refs; i++)
+ if (state->refs[i].id)
+ verbose(env, ",%d", state->refs[i].id);
+ }
+ if (state->in_callback_fn)
+ verbose(env, " cb");
+ if (state->in_async_callback_fn)
+ verbose(env, " async_cb");
+ verbose(env, "\n");
+ if (!print_all)
+ mark_verifier_state_clean(env);
+}
+
+static inline u32 vlog_alignment(u32 pos)
+{
+ return round_up(max(pos + BPF_LOG_MIN_ALIGNMENT / 2, BPF_LOG_ALIGNMENT),
+ BPF_LOG_MIN_ALIGNMENT) - pos - 1;
+}
+
+static void print_insn_state(struct bpf_verifier_env *env,
+ const struct bpf_func_state *state)
+{
+ if (env->prev_log_pos && env->prev_log_pos == env->log.end_pos) {
+ /* remove new line character */
+ bpf_vlog_reset(&env->log, env->prev_log_pos - 1);
+ verbose(env, "%*c;", vlog_alignment(env->prev_insn_print_pos), ' ');
+ } else {
+ verbose(env, "%d:", env->insn_idx);
+ }
+ print_verifier_state(env, state, false);
+}
+
+/* copy array src of length n * size bytes to dst. dst is reallocated if it's too
+ * small to hold src. This is different from krealloc since we don't want to preserve
+ * the contents of dst.
+ *
+ * Leaves dst untouched if src is NULL or length is zero. Returns NULL if memory could
+ * not be allocated.
+ */
+static void *copy_array(void *dst, const void *src, size_t n, size_t size, gfp_t flags)
+{
+ size_t alloc_bytes;
+ void *orig = dst;
+ size_t bytes;
+
+ if (ZERO_OR_NULL_PTR(src))
+ goto out;
+
+ if (unlikely(check_mul_overflow(n, size, &bytes)))
+ return NULL;
+
+ alloc_bytes = max(ksize(orig), kmalloc_size_roundup(bytes));
+ dst = krealloc(orig, alloc_bytes, flags);
+ if (!dst) {
+ kfree(orig);
+ return NULL;
+ }
+
+ memcpy(dst, src, bytes);
+out:
+ return dst ? dst : ZERO_SIZE_PTR;
+}
+
+/* resize an array from old_n items to new_n items. the array is reallocated if it's too
+ * small to hold new_n items. new items are zeroed out if the array grows.
+ *
+ * Contrary to krealloc_array, does not free arr if new_n is zero.
+ */
+static void *realloc_array(void *arr, size_t old_n, size_t new_n, size_t size)
+{
+ size_t alloc_size;
+ void *new_arr;
+
+ if (!new_n || old_n == new_n)
+ goto out;
+
+ alloc_size = kmalloc_size_roundup(size_mul(new_n, size));
+ new_arr = krealloc(arr, alloc_size, GFP_KERNEL);
+ if (!new_arr) {
+ kfree(arr);
+ return NULL;
+ }
+ arr = new_arr;
+
+ if (new_n > old_n)
+ memset(arr + old_n * size, 0, (new_n - old_n) * size);
+
+out:
+ return arr ? arr : ZERO_SIZE_PTR;
+}
+
+static int copy_reference_state(struct bpf_func_state *dst, const struct bpf_func_state *src)
+{
+ dst->refs = copy_array(dst->refs, src->refs, src->acquired_refs,
+ sizeof(struct bpf_reference_state), GFP_KERNEL);
+ if (!dst->refs)
+ return -ENOMEM;
+
+ dst->acquired_refs = src->acquired_refs;
+ return 0;
+}
+
+static int copy_stack_state(struct bpf_func_state *dst, const struct bpf_func_state *src)
+{
+ size_t n = src->allocated_stack / BPF_REG_SIZE;
+
+ dst->stack = copy_array(dst->stack, src->stack, n, sizeof(struct bpf_stack_state),
+ GFP_KERNEL);
+ if (!dst->stack)
+ return -ENOMEM;
+
+ dst->allocated_stack = src->allocated_stack;
+ return 0;
+}
+
+static int resize_reference_state(struct bpf_func_state *state, size_t n)
+{
+ state->refs = realloc_array(state->refs, state->acquired_refs, n,
+ sizeof(struct bpf_reference_state));
+ if (!state->refs)
+ return -ENOMEM;
+
+ state->acquired_refs = n;
+ return 0;
+}
+
+/* Possibly update state->allocated_stack to be at least size bytes. Also
+ * possibly update the function's high-water mark in its bpf_subprog_info.
+ */
+static int grow_stack_state(struct bpf_verifier_env *env, struct bpf_func_state *state, int size)
+{
+ size_t old_n = state->allocated_stack / BPF_REG_SIZE, n = size / BPF_REG_SIZE;
+
+ if (old_n >= n)
+ return 0;
+
+ state->stack = realloc_array(state->stack, old_n, n, sizeof(struct bpf_stack_state));
+ if (!state->stack)
+ return -ENOMEM;
+
+ state->allocated_stack = size;
+
+ /* update known max for given subprogram */
+ if (env->subprog_info[state->subprogno].stack_depth < size)
+ env->subprog_info[state->subprogno].stack_depth = size;
+
+ return 0;
+}
+
+/* Acquire a pointer id from the env and update the state->refs to include
+ * this new pointer reference.
+ * On success, returns a valid pointer id to associate with the register
+ * On failure, returns a negative errno.
+ */
+static int acquire_reference_state(struct bpf_verifier_env *env, int insn_idx)
+{
+ struct bpf_func_state *state = cur_func(env);
+ int new_ofs = state->acquired_refs;
+ int id, err;
+
+ err = resize_reference_state(state, state->acquired_refs + 1);
+ if (err)
+ return err;
+ id = ++env->id_gen;
+ state->refs[new_ofs].id = id;
+ state->refs[new_ofs].insn_idx = insn_idx;
+ state->refs[new_ofs].callback_ref = state->in_callback_fn ? state->frameno : 0;
+
+ return id;
+}
+
+/* release function corresponding to acquire_reference_state(). Idempotent. */
+static int release_reference_state(struct bpf_func_state *state, int ptr_id)
+{
+ int i, last_idx;
+
+ last_idx = state->acquired_refs - 1;
+ for (i = 0; i < state->acquired_refs; i++) {
+ if (state->refs[i].id == ptr_id) {
+ /* Cannot release caller references in callbacks */
+ if (state->in_callback_fn && state->refs[i].callback_ref != state->frameno)
+ return -EINVAL;
+ if (last_idx && i != last_idx)
+ memcpy(&state->refs[i], &state->refs[last_idx],
+ sizeof(*state->refs));
+ memset(&state->refs[last_idx], 0, sizeof(*state->refs));
+ state->acquired_refs--;
+ return 0;
+ }
+ }
+ return -EINVAL;
+}
+
+static void free_func_state(struct bpf_func_state *state)
+{
+ if (!state)
+ return;
+ kfree(state->refs);
+ kfree(state->stack);
+ kfree(state);
+}
+
+static void clear_jmp_history(struct bpf_verifier_state *state)
+{
+ kfree(state->jmp_history);
+ state->jmp_history = NULL;
+ state->jmp_history_cnt = 0;
+}
+
+static void free_verifier_state(struct bpf_verifier_state *state,
+ bool free_self)
+{
+ int i;
+
+ for (i = 0; i <= state->curframe; i++) {
+ free_func_state(state->frame[i]);
+ state->frame[i] = NULL;
+ }
+ clear_jmp_history(state);
+ if (free_self)
+ kfree(state);
+}
+
+/* copy verifier state from src to dst growing dst stack space
+ * when necessary to accommodate larger src stack
+ */
+static int copy_func_state(struct bpf_func_state *dst,
+ const struct bpf_func_state *src)
+{
+ int err;
+
+ memcpy(dst, src, offsetof(struct bpf_func_state, acquired_refs));
+ err = copy_reference_state(dst, src);
+ if (err)
+ return err;
+ return copy_stack_state(dst, src);
+}
+
+static int copy_verifier_state(struct bpf_verifier_state *dst_state,
+ const struct bpf_verifier_state *src)
+{
+ struct bpf_func_state *dst;
+ int i, err;
+
+ dst_state->jmp_history = copy_array(dst_state->jmp_history, src->jmp_history,
+ src->jmp_history_cnt, sizeof(struct bpf_idx_pair),
+ GFP_USER);
+ if (!dst_state->jmp_history)
+ return -ENOMEM;
+ dst_state->jmp_history_cnt = src->jmp_history_cnt;
+
+ /* if dst has more stack frames then src frame, free them */
+ for (i = src->curframe + 1; i <= dst_state->curframe; i++) {
+ free_func_state(dst_state->frame[i]);
+ dst_state->frame[i] = NULL;
+ }
+ dst_state->speculative = src->speculative;
+ dst_state->active_rcu_lock = src->active_rcu_lock;
+ dst_state->curframe = src->curframe;
+ dst_state->active_lock.ptr = src->active_lock.ptr;
+ dst_state->active_lock.id = src->active_lock.id;
+ dst_state->branches = src->branches;
+ dst_state->parent = src->parent;
+ dst_state->first_insn_idx = src->first_insn_idx;
+ dst_state->last_insn_idx = src->last_insn_idx;
+ dst_state->dfs_depth = src->dfs_depth;
+ dst_state->callback_unroll_depth = src->callback_unroll_depth;
+ dst_state->used_as_loop_entry = src->used_as_loop_entry;
+ for (i = 0; i <= src->curframe; i++) {
+ dst = dst_state->frame[i];
+ if (!dst) {
+ dst = kzalloc(sizeof(*dst), GFP_KERNEL);
+ if (!dst)
+ return -ENOMEM;
+ dst_state->frame[i] = dst;
+ }
+ err = copy_func_state(dst, src->frame[i]);
+ if (err)
+ return err;
+ }
+ return 0;
+}
+
+static u32 state_htab_size(struct bpf_verifier_env *env)
+{
+ return env->prog->len;
+}
+
+static struct bpf_verifier_state_list **explored_state(struct bpf_verifier_env *env, int idx)
+{
+ struct bpf_verifier_state *cur = env->cur_state;
+ struct bpf_func_state *state = cur->frame[cur->curframe];
+
+ return &env->explored_states[(idx ^ state->callsite) % state_htab_size(env)];
+}
+
+static bool same_callsites(struct bpf_verifier_state *a, struct bpf_verifier_state *b)
+{
+ int fr;
+
+ if (a->curframe != b->curframe)
+ return false;
+
+ for (fr = a->curframe; fr >= 0; fr--)
+ if (a->frame[fr]->callsite != b->frame[fr]->callsite)
+ return false;
+
+ return true;
+}
+
+/* Open coded iterators allow back-edges in the state graph in order to
+ * check unbounded loops that iterators.
+ *
+ * In is_state_visited() it is necessary to know if explored states are
+ * part of some loops in order to decide whether non-exact states
+ * comparison could be used:
+ * - non-exact states comparison establishes sub-state relation and uses
+ * read and precision marks to do so, these marks are propagated from
+ * children states and thus are not guaranteed to be final in a loop;
+ * - exact states comparison just checks if current and explored states
+ * are identical (and thus form a back-edge).
+ *
+ * Paper "A New Algorithm for Identifying Loops in Decompilation"
+ * by Tao Wei, Jian Mao, Wei Zou and Yu Chen [1] presents a convenient
+ * algorithm for loop structure detection and gives an overview of
+ * relevant terminology. It also has helpful illustrations.
+ *
+ * [1] https://api.semanticscholar.org/CorpusID:15784067
+ *
+ * We use a similar algorithm but because loop nested structure is
+ * irrelevant for verifier ours is significantly simpler and resembles
+ * strongly connected components algorithm from Sedgewick's textbook.
+ *
+ * Define topmost loop entry as a first node of the loop traversed in a
+ * depth first search starting from initial state. The goal of the loop
+ * tracking algorithm is to associate topmost loop entries with states
+ * derived from these entries.
+ *
+ * For each step in the DFS states traversal algorithm needs to identify
+ * the following situations:
+ *
+ * initial initial initial
+ * | | |
+ * V V V
+ * ... ... .---------> hdr
+ * | | | |
+ * V V | V
+ * cur .-> succ | .------...
+ * | | | | | |
+ * V | V | V V
+ * succ '-- cur | ... ...
+ * | | |
+ * | V V
+ * | succ <- cur
+ * | |
+ * | V
+ * | ...
+ * | |
+ * '----'
+ *
+ * (A) successor state of cur (B) successor state of cur or it's entry
+ * not yet traversed are in current DFS path, thus cur and succ
+ * are members of the same outermost loop
+ *
+ * initial initial
+ * | |
+ * V V
+ * ... ...
+ * | |
+ * V V
+ * .------... .------...
+ * | | | |
+ * V V V V
+ * .-> hdr ... ... ...
+ * | | | | |
+ * | V V V V
+ * | succ <- cur succ <- cur
+ * | | |
+ * | V V
+ * | ... ...
+ * | | |
+ * '----' exit
+ *
+ * (C) successor state of cur is a part of some loop but this loop
+ * does not include cur or successor state is not in a loop at all.
+ *
+ * Algorithm could be described as the following python code:
+ *
+ * traversed = set() # Set of traversed nodes
+ * entries = {} # Mapping from node to loop entry
+ * depths = {} # Depth level assigned to graph node
+ * path = set() # Current DFS path
+ *
+ * # Find outermost loop entry known for n
+ * def get_loop_entry(n):
+ * h = entries.get(n, None)
+ * while h in entries and entries[h] != h:
+ * h = entries[h]
+ * return h
+ *
+ * # Update n's loop entry if h's outermost entry comes
+ * # before n's outermost entry in current DFS path.
+ * def update_loop_entry(n, h):
+ * n1 = get_loop_entry(n) or n
+ * h1 = get_loop_entry(h) or h
+ * if h1 in path and depths[h1] <= depths[n1]:
+ * entries[n] = h1
+ *
+ * def dfs(n, depth):
+ * traversed.add(n)
+ * path.add(n)
+ * depths[n] = depth
+ * for succ in G.successors(n):
+ * if succ not in traversed:
+ * # Case A: explore succ and update cur's loop entry
+ * # only if succ's entry is in current DFS path.
+ * dfs(succ, depth + 1)
+ * h = get_loop_entry(succ)
+ * update_loop_entry(n, h)
+ * else:
+ * # Case B or C depending on `h1 in path` check in update_loop_entry().
+ * update_loop_entry(n, succ)
+ * path.remove(n)
+ *
+ * To adapt this algorithm for use with verifier:
+ * - use st->branch == 0 as a signal that DFS of succ had been finished
+ * and cur's loop entry has to be updated (case A), handle this in
+ * update_branch_counts();
+ * - use st->branch > 0 as a signal that st is in the current DFS path;
+ * - handle cases B and C in is_state_visited();
+ * - update topmost loop entry for intermediate states in get_loop_entry().
+ */
+static struct bpf_verifier_state *get_loop_entry(struct bpf_verifier_state *st)
+{
+ struct bpf_verifier_state *topmost = st->loop_entry, *old;
+
+ while (topmost && topmost->loop_entry && topmost != topmost->loop_entry)
+ topmost = topmost->loop_entry;
+ /* Update loop entries for intermediate states to avoid this
+ * traversal in future get_loop_entry() calls.
+ */
+ while (st && st->loop_entry != topmost) {
+ old = st->loop_entry;
+ st->loop_entry = topmost;
+ st = old;
+ }
+ return topmost;
+}
+
+static void update_loop_entry(struct bpf_verifier_state *cur, struct bpf_verifier_state *hdr)
+{
+ struct bpf_verifier_state *cur1, *hdr1;
+
+ cur1 = get_loop_entry(cur) ?: cur;
+ hdr1 = get_loop_entry(hdr) ?: hdr;
+ /* The head1->branches check decides between cases B and C in
+ * comment for get_loop_entry(). If hdr1->branches == 0 then
+ * head's topmost loop entry is not in current DFS path,
+ * hence 'cur' and 'hdr' are not in the same loop and there is
+ * no need to update cur->loop_entry.
+ */
+ if (hdr1->branches && hdr1->dfs_depth <= cur1->dfs_depth) {
+ cur->loop_entry = hdr;
+ hdr->used_as_loop_entry = true;
+ }
+}
+
+static void update_branch_counts(struct bpf_verifier_env *env, struct bpf_verifier_state *st)
+{
+ while (st) {
+ u32 br = --st->branches;
+
+ /* br == 0 signals that DFS exploration for 'st' is finished,
+ * thus it is necessary to update parent's loop entry if it
+ * turned out that st is a part of some loop.
+ * This is a part of 'case A' in get_loop_entry() comment.
+ */
+ if (br == 0 && st->parent && st->loop_entry)
+ update_loop_entry(st->parent, st->loop_entry);
+
+ /* WARN_ON(br > 1) technically makes sense here,
+ * but see comment in push_stack(), hence:
+ */
+ WARN_ONCE((int)br < 0,
+ "BUG update_branch_counts:branches_to_explore=%d\n",
+ br);
+ if (br)
+ break;
+ st = st->parent;
+ }
+}
+
+static int pop_stack(struct bpf_verifier_env *env, int *prev_insn_idx,
+ int *insn_idx, bool pop_log)
+{
+ struct bpf_verifier_state *cur = env->cur_state;
+ struct bpf_verifier_stack_elem *elem, *head = env->head;
+ int err;
+
+ if (env->head == NULL)
+ return -ENOENT;
+
+ if (cur) {
+ err = copy_verifier_state(cur, &head->st);
+ if (err)
+ return err;
+ }
+ if (pop_log)
+ bpf_vlog_reset(&env->log, head->log_pos);
+ if (insn_idx)
+ *insn_idx = head->insn_idx;
+ if (prev_insn_idx)
+ *prev_insn_idx = head->prev_insn_idx;
+ elem = head->next;
+ free_verifier_state(&head->st, false);
+ kfree(head);
+ env->head = elem;
+ env->stack_size--;
+ return 0;
+}
+
+static struct bpf_verifier_state *push_stack(struct bpf_verifier_env *env,
+ int insn_idx, int prev_insn_idx,
+ bool speculative)
+{
+ struct bpf_verifier_state *cur = env->cur_state;
+ struct bpf_verifier_stack_elem *elem;
+ int err;
+
+ elem = kzalloc(sizeof(struct bpf_verifier_stack_elem), GFP_KERNEL);
+ if (!elem)
+ goto err;
+
+ elem->insn_idx = insn_idx;
+ elem->prev_insn_idx = prev_insn_idx;
+ elem->next = env->head;
+ elem->log_pos = env->log.end_pos;
+ env->head = elem;
+ env->stack_size++;
+ err = copy_verifier_state(&elem->st, cur);
+ if (err)
+ goto err;
+ elem->st.speculative |= speculative;
+ if (env->stack_size > BPF_COMPLEXITY_LIMIT_JMP_SEQ) {
+ verbose(env, "The sequence of %d jumps is too complex.\n",
+ env->stack_size);
+ goto err;
+ }
+ if (elem->st.parent) {
+ ++elem->st.parent->branches;
+ /* WARN_ON(branches > 2) technically makes sense here,
+ * but
+ * 1. speculative states will bump 'branches' for non-branch
+ * instructions
+ * 2. is_state_visited() heuristics may decide not to create
+ * a new state for a sequence of branches and all such current
+ * and cloned states will be pointing to a single parent state
+ * which might have large 'branches' count.
+ */
+ }
+ return &elem->st;
+err:
+ free_verifier_state(env->cur_state, true);
+ env->cur_state = NULL;
+ /* pop all elements and return */
+ while (!pop_stack(env, NULL, NULL, false));
+ return NULL;
+}
+
+#define CALLER_SAVED_REGS 6
+static const int caller_saved[CALLER_SAVED_REGS] = {
+ BPF_REG_0, BPF_REG_1, BPF_REG_2, BPF_REG_3, BPF_REG_4, BPF_REG_5
+};
+
+/* This helper doesn't clear reg->id */
+static void ___mark_reg_known(struct bpf_reg_state *reg, u64 imm)
+{
+ reg->var_off = tnum_const(imm);
+ reg->smin_value = (s64)imm;
+ reg->smax_value = (s64)imm;
+ reg->umin_value = imm;
+ reg->umax_value = imm;
+
+ reg->s32_min_value = (s32)imm;
+ reg->s32_max_value = (s32)imm;
+ reg->u32_min_value = (u32)imm;
+ reg->u32_max_value = (u32)imm;
+}
+
+/* Mark the unknown part of a register (variable offset or scalar value) as
+ * known to have the value @imm.
+ */
+static void __mark_reg_known(struct bpf_reg_state *reg, u64 imm)
+{
+ /* Clear off and union(map_ptr, range) */
+ memset(((u8 *)reg) + sizeof(reg->type), 0,
+ offsetof(struct bpf_reg_state, var_off) - sizeof(reg->type));
+ reg->id = 0;
+ reg->ref_obj_id = 0;
+ ___mark_reg_known(reg, imm);
+}
+
+static void __mark_reg32_known(struct bpf_reg_state *reg, u64 imm)
+{
+ reg->var_off = tnum_const_subreg(reg->var_off, imm);
+ reg->s32_min_value = (s32)imm;
+ reg->s32_max_value = (s32)imm;
+ reg->u32_min_value = (u32)imm;
+ reg->u32_max_value = (u32)imm;
+}
+
+/* Mark the 'variable offset' part of a register as zero. This should be
+ * used only on registers holding a pointer type.
+ */
+static void __mark_reg_known_zero(struct bpf_reg_state *reg)
+{
+ __mark_reg_known(reg, 0);
+}
+
+static void __mark_reg_const_zero(struct bpf_reg_state *reg)
+{
+ __mark_reg_known(reg, 0);
+ reg->type = SCALAR_VALUE;
+}
+
+static void mark_reg_known_zero(struct bpf_verifier_env *env,
+ struct bpf_reg_state *regs, u32 regno)
+{
+ if (WARN_ON(regno >= MAX_BPF_REG)) {
+ verbose(env, "mark_reg_known_zero(regs, %u)\n", regno);
+ /* Something bad happened, let's kill all regs */
+ for (regno = 0; regno < MAX_BPF_REG; regno++)
+ __mark_reg_not_init(env, regs + regno);
+ return;
+ }
+ __mark_reg_known_zero(regs + regno);
+}
+
+static void __mark_dynptr_reg(struct bpf_reg_state *reg, enum bpf_dynptr_type type,
+ bool first_slot, int dynptr_id)
+{
+ /* reg->type has no meaning for STACK_DYNPTR, but when we set reg for
+ * callback arguments, it does need to be CONST_PTR_TO_DYNPTR, so simply
+ * set it unconditionally as it is ignored for STACK_DYNPTR anyway.
+ */
+ __mark_reg_known_zero(reg);
+ reg->type = CONST_PTR_TO_DYNPTR;
+ /* Give each dynptr a unique id to uniquely associate slices to it. */
+ reg->id = dynptr_id;
+ reg->dynptr.type = type;
+ reg->dynptr.first_slot = first_slot;
+}
+
+static void mark_ptr_not_null_reg(struct bpf_reg_state *reg)
+{
+ if (base_type(reg->type) == PTR_TO_MAP_VALUE) {
+ const struct bpf_map *map = reg->map_ptr;
+
+ if (map->inner_map_meta) {
+ reg->type = CONST_PTR_TO_MAP;
+ reg->map_ptr = map->inner_map_meta;
+ /* transfer reg's id which is unique for every map_lookup_elem
+ * as UID of the inner map.
+ */
+ if (btf_record_has_field(map->inner_map_meta->record, BPF_TIMER))
+ reg->map_uid = reg->id;
+ } else if (map->map_type == BPF_MAP_TYPE_XSKMAP) {
+ reg->type = PTR_TO_XDP_SOCK;
+ } else if (map->map_type == BPF_MAP_TYPE_SOCKMAP ||
+ map->map_type == BPF_MAP_TYPE_SOCKHASH) {
+ reg->type = PTR_TO_SOCKET;
+ } else {
+ reg->type = PTR_TO_MAP_VALUE;
+ }
+ return;
+ }
+
+ reg->type &= ~PTR_MAYBE_NULL;
+}
+
+static void mark_reg_graph_node(struct bpf_reg_state *regs, u32 regno,
+ struct btf_field_graph_root *ds_head)
+{
+ __mark_reg_known_zero(&regs[regno]);
+ regs[regno].type = PTR_TO_BTF_ID | MEM_ALLOC;
+ regs[regno].btf = ds_head->btf;
+ regs[regno].btf_id = ds_head->value_btf_id;
+ regs[regno].off = ds_head->node_offset;
+}
+
+static bool reg_is_pkt_pointer(const struct bpf_reg_state *reg)
+{
+ return type_is_pkt_pointer(reg->type);
+}
+
+static bool reg_is_pkt_pointer_any(const struct bpf_reg_state *reg)
+{
+ return reg_is_pkt_pointer(reg) ||
+ reg->type == PTR_TO_PACKET_END;
+}
+
+static bool reg_is_dynptr_slice_pkt(const struct bpf_reg_state *reg)
+{
+ return base_type(reg->type) == PTR_TO_MEM &&
+ (reg->type & DYNPTR_TYPE_SKB || reg->type & DYNPTR_TYPE_XDP);
+}
+
+/* Unmodified PTR_TO_PACKET[_META,_END] register from ctx access. */
+static bool reg_is_init_pkt_pointer(const struct bpf_reg_state *reg,
+ enum bpf_reg_type which)
+{
+ /* The register can already have a range from prior markings.
+ * This is fine as long as it hasn't been advanced from its
+ * origin.
+ */
+ return reg->type == which &&
+ reg->id == 0 &&
+ reg->off == 0 &&
+ tnum_equals_const(reg->var_off, 0);
+}
+
+/* Reset the min/max bounds of a register */
+static void __mark_reg_unbounded(struct bpf_reg_state *reg)
+{
+ reg->smin_value = S64_MIN;
+ reg->smax_value = S64_MAX;
+ reg->umin_value = 0;
+ reg->umax_value = U64_MAX;
+
+ reg->s32_min_value = S32_MIN;
+ reg->s32_max_value = S32_MAX;
+ reg->u32_min_value = 0;
+ reg->u32_max_value = U32_MAX;
+}
+
+static void __mark_reg64_unbounded(struct bpf_reg_state *reg)
+{
+ reg->smin_value = S64_MIN;
+ reg->smax_value = S64_MAX;
+ reg->umin_value = 0;
+ reg->umax_value = U64_MAX;
+}
+
+static void __mark_reg32_unbounded(struct bpf_reg_state *reg)
+{
+ reg->s32_min_value = S32_MIN;
+ reg->s32_max_value = S32_MAX;
+ reg->u32_min_value = 0;
+ reg->u32_max_value = U32_MAX;
+}
+
+static void __update_reg32_bounds(struct bpf_reg_state *reg)
+{
+ struct tnum var32_off = tnum_subreg(reg->var_off);
+
+ /* min signed is max(sign bit) | min(other bits) */
+ reg->s32_min_value = max_t(s32, reg->s32_min_value,
+ var32_off.value | (var32_off.mask & S32_MIN));
+ /* max signed is min(sign bit) | max(other bits) */
+ reg->s32_max_value = min_t(s32, reg->s32_max_value,
+ var32_off.value | (var32_off.mask & S32_MAX));
+ reg->u32_min_value = max_t(u32, reg->u32_min_value, (u32)var32_off.value);
+ reg->u32_max_value = min(reg->u32_max_value,
+ (u32)(var32_off.value | var32_off.mask));
+}
+
+static void __update_reg64_bounds(struct bpf_reg_state *reg)
+{
+ /* min signed is max(sign bit) | min(other bits) */
+ reg->smin_value = max_t(s64, reg->smin_value,
+ reg->var_off.value | (reg->var_off.mask & S64_MIN));
+ /* max signed is min(sign bit) | max(other bits) */
+ reg->smax_value = min_t(s64, reg->smax_value,
+ reg->var_off.value | (reg->var_off.mask & S64_MAX));
+ reg->umin_value = max(reg->umin_value, reg->var_off.value);
+ reg->umax_value = min(reg->umax_value,
+ reg->var_off.value | reg->var_off.mask);
+}
+
+static void __update_reg_bounds(struct bpf_reg_state *reg)
+{
+ __update_reg32_bounds(reg);
+ __update_reg64_bounds(reg);
+}
+
+/* Uses signed min/max values to inform unsigned, and vice-versa */
+static void __reg32_deduce_bounds(struct bpf_reg_state *reg)
+{
+ /* Learn sign from signed bounds.
+ * If we cannot cross the sign boundary, then signed and unsigned bounds
+ * are the same, so combine. This works even in the negative case, e.g.
+ * -3 s<= x s<= -1 implies 0xf...fd u<= x u<= 0xf...ff.
+ */
+ if (reg->s32_min_value >= 0 || reg->s32_max_value < 0) {
+ reg->s32_min_value = reg->u32_min_value =
+ max_t(u32, reg->s32_min_value, reg->u32_min_value);
+ reg->s32_max_value = reg->u32_max_value =
+ min_t(u32, reg->s32_max_value, reg->u32_max_value);
+ return;
+ }
+ /* Learn sign from unsigned bounds. Signed bounds cross the sign
+ * boundary, so we must be careful.
+ */
+ if ((s32)reg->u32_max_value >= 0) {
+ /* Positive. We can't learn anything from the smin, but smax
+ * is positive, hence safe.
+ */
+ reg->s32_min_value = reg->u32_min_value;
+ reg->s32_max_value = reg->u32_max_value =
+ min_t(u32, reg->s32_max_value, reg->u32_max_value);
+ } else if ((s32)reg->u32_min_value < 0) {
+ /* Negative. We can't learn anything from the smax, but smin
+ * is negative, hence safe.
+ */
+ reg->s32_min_value = reg->u32_min_value =
+ max_t(u32, reg->s32_min_value, reg->u32_min_value);
+ reg->s32_max_value = reg->u32_max_value;
+ }
+}
+
+static void __reg64_deduce_bounds(struct bpf_reg_state *reg)
+{
+ /* Learn sign from signed bounds.
+ * If we cannot cross the sign boundary, then signed and unsigned bounds
+ * are the same, so combine. This works even in the negative case, e.g.
+ * -3 s<= x s<= -1 implies 0xf...fd u<= x u<= 0xf...ff.
+ */
+ if (reg->smin_value >= 0 || reg->smax_value < 0) {
+ reg->smin_value = reg->umin_value = max_t(u64, reg->smin_value,
+ reg->umin_value);
+ reg->smax_value = reg->umax_value = min_t(u64, reg->smax_value,
+ reg->umax_value);
+ return;
+ }
+ /* Learn sign from unsigned bounds. Signed bounds cross the sign
+ * boundary, so we must be careful.
+ */
+ if ((s64)reg->umax_value >= 0) {
+ /* Positive. We can't learn anything from the smin, but smax
+ * is positive, hence safe.
+ */
+ reg->smin_value = reg->umin_value;
+ reg->smax_value = reg->umax_value = min_t(u64, reg->smax_value,
+ reg->umax_value);
+ } else if ((s64)reg->umin_value < 0) {
+ /* Negative. We can't learn anything from the smax, but smin
+ * is negative, hence safe.
+ */
+ reg->smin_value = reg->umin_value = max_t(u64, reg->smin_value,
+ reg->umin_value);
+ reg->smax_value = reg->umax_value;
+ }
+}
+
+static void __reg_deduce_bounds(struct bpf_reg_state *reg)
+{
+ __reg32_deduce_bounds(reg);
+ __reg64_deduce_bounds(reg);
+}
+
+/* Attempts to improve var_off based on unsigned min/max information */
+static void __reg_bound_offset(struct bpf_reg_state *reg)
+{
+ struct tnum var64_off = tnum_intersect(reg->var_off,
+ tnum_range(reg->umin_value,
+ reg->umax_value));
+ struct tnum var32_off = tnum_intersect(tnum_subreg(var64_off),
+ tnum_range(reg->u32_min_value,
+ reg->u32_max_value));
+
+ reg->var_off = tnum_or(tnum_clear_subreg(var64_off), var32_off);
+}
+
+static void reg_bounds_sync(struct bpf_reg_state *reg)
+{
+ /* We might have learned new bounds from the var_off. */
+ __update_reg_bounds(reg);
+ /* We might have learned something about the sign bit. */
+ __reg_deduce_bounds(reg);
+ /* We might have learned some bits from the bounds. */
+ __reg_bound_offset(reg);
+ /* Intersecting with the old var_off might have improved our bounds
+ * slightly, e.g. if umax was 0x7f...f and var_off was (0; 0xf...fc),
+ * then new var_off is (0; 0x7f...fc) which improves our umax.
+ */
+ __update_reg_bounds(reg);
+}
+
+static bool __reg32_bound_s64(s32 a)
+{
+ return a >= 0 && a <= S32_MAX;
+}
+
+static void __reg_assign_32_into_64(struct bpf_reg_state *reg)
+{
+ reg->umin_value = reg->u32_min_value;
+ reg->umax_value = reg->u32_max_value;
+
+ /* Attempt to pull 32-bit signed bounds into 64-bit bounds but must
+ * be positive otherwise set to worse case bounds and refine later
+ * from tnum.
+ */
+ if (__reg32_bound_s64(reg->s32_min_value) &&
+ __reg32_bound_s64(reg->s32_max_value)) {
+ reg->smin_value = reg->s32_min_value;
+ reg->smax_value = reg->s32_max_value;
+ } else {
+ reg->smin_value = 0;
+ reg->smax_value = U32_MAX;
+ }
+}
+
+static void __reg_combine_32_into_64(struct bpf_reg_state *reg)
+{
+ /* special case when 64-bit register has upper 32-bit register
+ * zeroed. Typically happens after zext or <<32, >>32 sequence
+ * allowing us to use 32-bit bounds directly,
+ */
+ if (tnum_equals_const(tnum_clear_subreg(reg->var_off), 0)) {
+ __reg_assign_32_into_64(reg);
+ } else {
+ /* Otherwise the best we can do is push lower 32bit known and
+ * unknown bits into register (var_off set from jmp logic)
+ * then learn as much as possible from the 64-bit tnum
+ * known and unknown bits. The previous smin/smax bounds are
+ * invalid here because of jmp32 compare so mark them unknown
+ * so they do not impact tnum bounds calculation.
+ */
+ __mark_reg64_unbounded(reg);
+ }
+ reg_bounds_sync(reg);
+}
+
+static bool __reg64_bound_s32(s64 a)
+{
+ return a >= S32_MIN && a <= S32_MAX;
+}
+
+static bool __reg64_bound_u32(u64 a)
+{
+ return a >= U32_MIN && a <= U32_MAX;
+}
+
+static void __reg_combine_64_into_32(struct bpf_reg_state *reg)
+{
+ __mark_reg32_unbounded(reg);
+ if (__reg64_bound_s32(reg->smin_value) && __reg64_bound_s32(reg->smax_value)) {
+ reg->s32_min_value = (s32)reg->smin_value;
+ reg->s32_max_value = (s32)reg->smax_value;
+ }
+ if (__reg64_bound_u32(reg->umin_value) && __reg64_bound_u32(reg->umax_value)) {
+ reg->u32_min_value = (u32)reg->umin_value;
+ reg->u32_max_value = (u32)reg->umax_value;
+ }
+ reg_bounds_sync(reg);
+}
+
+/* Mark a register as having a completely unknown (scalar) value. */
+static void __mark_reg_unknown(const struct bpf_verifier_env *env,
+ struct bpf_reg_state *reg)
+{
+ /*
+ * Clear type, off, and union(map_ptr, range) and
+ * padding between 'type' and union
+ */
+ memset(reg, 0, offsetof(struct bpf_reg_state, var_off));
+ reg->type = SCALAR_VALUE;
+ reg->id = 0;
+ reg->ref_obj_id = 0;
+ reg->var_off = tnum_unknown;
+ reg->frameno = 0;
+ reg->precise = !env->bpf_capable;
+ __mark_reg_unbounded(reg);
+}
+
+static void mark_reg_unknown(struct bpf_verifier_env *env,
+ struct bpf_reg_state *regs, u32 regno)
+{
+ if (WARN_ON(regno >= MAX_BPF_REG)) {
+ verbose(env, "mark_reg_unknown(regs, %u)\n", regno);
+ /* Something bad happened, let's kill all regs except FP */
+ for (regno = 0; regno < BPF_REG_FP; regno++)
+ __mark_reg_not_init(env, regs + regno);
+ return;
+ }
+ __mark_reg_unknown(env, regs + regno);
+}
+
+static void __mark_reg_not_init(const struct bpf_verifier_env *env,
+ struct bpf_reg_state *reg)
+{
+ __mark_reg_unknown(env, reg);
+ reg->type = NOT_INIT;
+}
+
+static void mark_reg_not_init(struct bpf_verifier_env *env,
+ struct bpf_reg_state *regs, u32 regno)
+{
+ if (WARN_ON(regno >= MAX_BPF_REG)) {
+ verbose(env, "mark_reg_not_init(regs, %u)\n", regno);
+ /* Something bad happened, let's kill all regs except FP */
+ for (regno = 0; regno < BPF_REG_FP; regno++)
+ __mark_reg_not_init(env, regs + regno);
+ return;
+ }
+ __mark_reg_not_init(env, regs + regno);
+}
+
+static void mark_btf_ld_reg(struct bpf_verifier_env *env,
+ struct bpf_reg_state *regs, u32 regno,
+ enum bpf_reg_type reg_type,
+ struct btf *btf, u32 btf_id,
+ enum bpf_type_flag flag)
+{
+ if (reg_type == SCALAR_VALUE) {
+ mark_reg_unknown(env, regs, regno);
+ return;
+ }
+ mark_reg_known_zero(env, regs, regno);
+ regs[regno].type = PTR_TO_BTF_ID | flag;
+ regs[regno].btf = btf;
+ regs[regno].btf_id = btf_id;
+}
+
+#define DEF_NOT_SUBREG (0)
+static void init_reg_state(struct bpf_verifier_env *env,
+ struct bpf_func_state *state)
+{
+ struct bpf_reg_state *regs = state->regs;
+ int i;
+
+ for (i = 0; i < MAX_BPF_REG; i++) {
+ mark_reg_not_init(env, regs, i);
+ regs[i].live = REG_LIVE_NONE;
+ regs[i].parent = NULL;
+ regs[i].subreg_def = DEF_NOT_SUBREG;
+ }
+
+ /* frame pointer */
+ regs[BPF_REG_FP].type = PTR_TO_STACK;
+ mark_reg_known_zero(env, regs, BPF_REG_FP);
+ regs[BPF_REG_FP].frameno = state->frameno;
+}
+
+#define BPF_MAIN_FUNC (-1)
+static void init_func_state(struct bpf_verifier_env *env,
+ struct bpf_func_state *state,
+ int callsite, int frameno, int subprogno)
+{
+ state->callsite = callsite;
+ state->frameno = frameno;
+ state->subprogno = subprogno;
+ state->callback_ret_range = tnum_range(0, 0);
+ init_reg_state(env, state);
+ mark_verifier_state_scratched(env);
+}
+
+/* Similar to push_stack(), but for async callbacks */
+static struct bpf_verifier_state *push_async_cb(struct bpf_verifier_env *env,
+ int insn_idx, int prev_insn_idx,
+ int subprog)
+{
+ struct bpf_verifier_stack_elem *elem;
+ struct bpf_func_state *frame;
+
+ elem = kzalloc(sizeof(struct bpf_verifier_stack_elem), GFP_KERNEL);
+ if (!elem)
+ goto err;
+
+ elem->insn_idx = insn_idx;
+ elem->prev_insn_idx = prev_insn_idx;
+ elem->next = env->head;
+ elem->log_pos = env->log.end_pos;
+ env->head = elem;
+ env->stack_size++;
+ if (env->stack_size > BPF_COMPLEXITY_LIMIT_JMP_SEQ) {
+ verbose(env,
+ "The sequence of %d jumps is too complex for async cb.\n",
+ env->stack_size);
+ goto err;
+ }
+ /* Unlike push_stack() do not copy_verifier_state().
+ * The caller state doesn't matter.
+ * This is async callback. It starts in a fresh stack.
+ * Initialize it similar to do_check_common().
+ */
+ elem->st.branches = 1;
+ frame = kzalloc(sizeof(*frame), GFP_KERNEL);
+ if (!frame)
+ goto err;
+ init_func_state(env, frame,
+ BPF_MAIN_FUNC /* callsite */,
+ 0 /* frameno within this callchain */,
+ subprog /* subprog number within this prog */);
+ elem->st.frame[0] = frame;
+ return &elem->st;
+err:
+ free_verifier_state(env->cur_state, true);
+ env->cur_state = NULL;
+ /* pop all elements and return */
+ while (!pop_stack(env, NULL, NULL, false));
+ return NULL;
+}
+
+
+enum reg_arg_type {
+ SRC_OP, /* register is used as source operand */
+ DST_OP, /* register is used as destination operand */
+ DST_OP_NO_MARK /* same as above, check only, don't mark */
+};
+
+static int cmp_subprogs(const void *a, const void *b)
+{
+ return ((struct bpf_subprog_info *)a)->start -
+ ((struct bpf_subprog_info *)b)->start;
+}
+
+static int find_subprog(struct bpf_verifier_env *env, int off)
+{
+ struct bpf_subprog_info *p;
+
+ p = bsearch(&off, env->subprog_info, env->subprog_cnt,
+ sizeof(env->subprog_info[0]), cmp_subprogs);
+ if (!p)
+ return -ENOENT;
+ return p - env->subprog_info;
+
+}
+
+static int add_subprog(struct bpf_verifier_env *env, int off)
+{
+ int insn_cnt = env->prog->len;
+ int ret;
+
+ if (off >= insn_cnt || off < 0) {
+ verbose(env, "call to invalid destination\n");
+ return -EINVAL;
+ }
+ ret = find_subprog(env, off);
+ if (ret >= 0)
+ return ret;
+ if (env->subprog_cnt >= BPF_MAX_SUBPROGS) {
+ verbose(env, "too many subprograms\n");
+ return -E2BIG;
+ }
+ /* determine subprog starts. The end is one before the next starts */
+ env->subprog_info[env->subprog_cnt++].start = off;
+ sort(env->subprog_info, env->subprog_cnt,
+ sizeof(env->subprog_info[0]), cmp_subprogs, NULL);
+ return env->subprog_cnt - 1;
+}
+
+#define MAX_KFUNC_DESCS 256
+#define MAX_KFUNC_BTFS 256
+
+struct bpf_kfunc_desc {
+ struct btf_func_model func_model;
+ u32 func_id;
+ s32 imm;
+ u16 offset;
+ unsigned long addr;
+};
+
+struct bpf_kfunc_btf {
+ struct btf *btf;
+ struct module *module;
+ u16 offset;
+};
+
+struct bpf_kfunc_desc_tab {
+ /* Sorted by func_id (BTF ID) and offset (fd_array offset) during
+ * verification. JITs do lookups by bpf_insn, where func_id may not be
+ * available, therefore at the end of verification do_misc_fixups()
+ * sorts this by imm and offset.
+ */
+ struct bpf_kfunc_desc descs[MAX_KFUNC_DESCS];
+ u32 nr_descs;
+};
+
+struct bpf_kfunc_btf_tab {
+ struct bpf_kfunc_btf descs[MAX_KFUNC_BTFS];
+ u32 nr_descs;
+};
+
+static int kfunc_desc_cmp_by_id_off(const void *a, const void *b)
+{
+ const struct bpf_kfunc_desc *d0 = a;
+ const struct bpf_kfunc_desc *d1 = b;
+
+ /* func_id is not greater than BTF_MAX_TYPE */
+ return d0->func_id - d1->func_id ?: d0->offset - d1->offset;
+}
+
+static int kfunc_btf_cmp_by_off(const void *a, const void *b)
+{
+ const struct bpf_kfunc_btf *d0 = a;
+ const struct bpf_kfunc_btf *d1 = b;
+
+ return d0->offset - d1->offset;
+}
+
+static const struct bpf_kfunc_desc *
+find_kfunc_desc(const struct bpf_prog *prog, u32 func_id, u16 offset)
+{
+ struct bpf_kfunc_desc desc = {
+ .func_id = func_id,
+ .offset = offset,
+ };
+ struct bpf_kfunc_desc_tab *tab;
+
+ tab = prog->aux->kfunc_tab;
+ return bsearch(&desc, tab->descs, tab->nr_descs,
+ sizeof(tab->descs[0]), kfunc_desc_cmp_by_id_off);
+}
+
+int bpf_get_kfunc_addr(const struct bpf_prog *prog, u32 func_id,
+ u16 btf_fd_idx, u8 **func_addr)
+{
+ const struct bpf_kfunc_desc *desc;
+
+ desc = find_kfunc_desc(prog, func_id, btf_fd_idx);
+ if (!desc)
+ return -EFAULT;
+
+ *func_addr = (u8 *)desc->addr;
+ return 0;
+}
+
+static struct btf *__find_kfunc_desc_btf(struct bpf_verifier_env *env,
+ s16 offset)
+{
+ struct bpf_kfunc_btf kf_btf = { .offset = offset };
+ struct bpf_kfunc_btf_tab *tab;
+ struct bpf_kfunc_btf *b;
+ struct module *mod;
+ struct btf *btf;
+ int btf_fd;
+
+ tab = env->prog->aux->kfunc_btf_tab;
+ b = bsearch(&kf_btf, tab->descs, tab->nr_descs,
+ sizeof(tab->descs[0]), kfunc_btf_cmp_by_off);
+ if (!b) {
+ if (tab->nr_descs == MAX_KFUNC_BTFS) {
+ verbose(env, "too many different module BTFs\n");
+ return ERR_PTR(-E2BIG);
+ }
+
+ if (bpfptr_is_null(env->fd_array)) {
+ verbose(env, "kfunc offset > 0 without fd_array is invalid\n");
+ return ERR_PTR(-EPROTO);
+ }
+
+ if (copy_from_bpfptr_offset(&btf_fd, env->fd_array,
+ offset * sizeof(btf_fd),
+ sizeof(btf_fd)))
+ return ERR_PTR(-EFAULT);
+
+ btf = btf_get_by_fd(btf_fd);
+ if (IS_ERR(btf)) {
+ verbose(env, "invalid module BTF fd specified\n");
+ return btf;
+ }
+
+ if (!btf_is_module(btf)) {
+ verbose(env, "BTF fd for kfunc is not a module BTF\n");
+ btf_put(btf);
+ return ERR_PTR(-EINVAL);
+ }
+
+ mod = btf_try_get_module(btf);
+ if (!mod) {
+ btf_put(btf);
+ return ERR_PTR(-ENXIO);
+ }
+
+ b = &tab->descs[tab->nr_descs++];
+ b->btf = btf;
+ b->module = mod;
+ b->offset = offset;
+
+ sort(tab->descs, tab->nr_descs, sizeof(tab->descs[0]),
+ kfunc_btf_cmp_by_off, NULL);
+ }
+ return b->btf;
+}
+
+void bpf_free_kfunc_btf_tab(struct bpf_kfunc_btf_tab *tab)
+{
+ if (!tab)
+ return;
+
+ while (tab->nr_descs--) {
+ module_put(tab->descs[tab->nr_descs].module);
+ btf_put(tab->descs[tab->nr_descs].btf);
+ }
+ kfree(tab);
+}
+
+static struct btf *find_kfunc_desc_btf(struct bpf_verifier_env *env, s16 offset)
+{
+ if (offset) {
+ if (offset < 0) {
+ /* In the future, this can be allowed to increase limit
+ * of fd index into fd_array, interpreted as u16.
+ */
+ verbose(env, "negative offset disallowed for kernel module function call\n");
+ return ERR_PTR(-EINVAL);
+ }
+
+ return __find_kfunc_desc_btf(env, offset);
+ }
+ return btf_vmlinux ?: ERR_PTR(-ENOENT);
+}
+
+static int add_kfunc_call(struct bpf_verifier_env *env, u32 func_id, s16 offset)
+{
+ const struct btf_type *func, *func_proto;
+ struct bpf_kfunc_btf_tab *btf_tab;
+ struct bpf_kfunc_desc_tab *tab;
+ struct bpf_prog_aux *prog_aux;
+ struct bpf_kfunc_desc *desc;
+ const char *func_name;
+ struct btf *desc_btf;
+ unsigned long call_imm;
+ unsigned long addr;
+ int err;
+
+ prog_aux = env->prog->aux;
+ tab = prog_aux->kfunc_tab;
+ btf_tab = prog_aux->kfunc_btf_tab;
+ if (!tab) {
+ if (!btf_vmlinux) {
+ verbose(env, "calling kernel function is not supported without CONFIG_DEBUG_INFO_BTF\n");
+ return -ENOTSUPP;
+ }
+
+ if (!env->prog->jit_requested) {
+ verbose(env, "JIT is required for calling kernel function\n");
+ return -ENOTSUPP;
+ }
+
+ if (!bpf_jit_supports_kfunc_call()) {
+ verbose(env, "JIT does not support calling kernel function\n");
+ return -ENOTSUPP;
+ }
+
+ if (!env->prog->gpl_compatible) {
+ verbose(env, "cannot call kernel function from non-GPL compatible program\n");
+ return -EINVAL;
+ }
+
+ tab = kzalloc(sizeof(*tab), GFP_KERNEL);
+ if (!tab)
+ return -ENOMEM;
+ prog_aux->kfunc_tab = tab;
+ }
+
+ /* func_id == 0 is always invalid, but instead of returning an error, be
+ * conservative and wait until the code elimination pass before returning
+ * error, so that invalid calls that get pruned out can be in BPF programs
+ * loaded from userspace. It is also required that offset be untouched
+ * for such calls.
+ */
+ if (!func_id && !offset)
+ return 0;
+
+ if (!btf_tab && offset) {
+ btf_tab = kzalloc(sizeof(*btf_tab), GFP_KERNEL);
+ if (!btf_tab)
+ return -ENOMEM;
+ prog_aux->kfunc_btf_tab = btf_tab;
+ }
+
+ desc_btf = find_kfunc_desc_btf(env, offset);
+ if (IS_ERR(desc_btf)) {
+ verbose(env, "failed to find BTF for kernel function\n");
+ return PTR_ERR(desc_btf);
+ }
+
+ if (find_kfunc_desc(env->prog, func_id, offset))
+ return 0;
+
+ if (tab->nr_descs == MAX_KFUNC_DESCS) {
+ verbose(env, "too many different kernel function calls\n");
+ return -E2BIG;
+ }
+
+ func = btf_type_by_id(desc_btf, func_id);
+ if (!func || !btf_type_is_func(func)) {
+ verbose(env, "kernel btf_id %u is not a function\n",
+ func_id);
+ return -EINVAL;
+ }
+ func_proto = btf_type_by_id(desc_btf, func->type);
+ if (!func_proto || !btf_type_is_func_proto(func_proto)) {
+ verbose(env, "kernel function btf_id %u does not have a valid func_proto\n",
+ func_id);
+ return -EINVAL;
+ }
+
+ func_name = btf_name_by_offset(desc_btf, func->name_off);
+ addr = kallsyms_lookup_name(func_name);
+ if (!addr) {
+ verbose(env, "cannot find address for kernel function %s\n",
+ func_name);
+ return -EINVAL;
+ }
+ specialize_kfunc(env, func_id, offset, &addr);
+
+ if (bpf_jit_supports_far_kfunc_call()) {
+ call_imm = func_id;
+ } else {
+ call_imm = BPF_CALL_IMM(addr);
+ /* Check whether the relative offset overflows desc->imm */
+ if ((unsigned long)(s32)call_imm != call_imm) {
+ verbose(env, "address of kernel function %s is out of range\n",
+ func_name);
+ return -EINVAL;
+ }
+ }
+
+ if (bpf_dev_bound_kfunc_id(func_id)) {
+ err = bpf_dev_bound_kfunc_check(&env->log, prog_aux);
+ if (err)
+ return err;
+ }
+
+ desc = &tab->descs[tab->nr_descs++];
+ desc->func_id = func_id;
+ desc->imm = call_imm;
+ desc->offset = offset;
+ desc->addr = addr;
+ err = btf_distill_func_proto(&env->log, desc_btf,
+ func_proto, func_name,
+ &desc->func_model);
+ if (!err)
+ sort(tab->descs, tab->nr_descs, sizeof(tab->descs[0]),
+ kfunc_desc_cmp_by_id_off, NULL);
+ return err;
+}
+
+static int kfunc_desc_cmp_by_imm_off(const void *a, const void *b)
+{
+ const struct bpf_kfunc_desc *d0 = a;
+ const struct bpf_kfunc_desc *d1 = b;
+
+ if (d0->imm != d1->imm)
+ return d0->imm < d1->imm ? -1 : 1;
+ if (d0->offset != d1->offset)
+ return d0->offset < d1->offset ? -1 : 1;
+ return 0;
+}
+
+static void sort_kfunc_descs_by_imm_off(struct bpf_prog *prog)
+{
+ struct bpf_kfunc_desc_tab *tab;
+
+ tab = prog->aux->kfunc_tab;
+ if (!tab)
+ return;
+
+ sort(tab->descs, tab->nr_descs, sizeof(tab->descs[0]),
+ kfunc_desc_cmp_by_imm_off, NULL);
+}
+
+bool bpf_prog_has_kfunc_call(const struct bpf_prog *prog)
+{
+ return !!prog->aux->kfunc_tab;
+}
+
+const struct btf_func_model *
+bpf_jit_find_kfunc_model(const struct bpf_prog *prog,
+ const struct bpf_insn *insn)
+{
+ const struct bpf_kfunc_desc desc = {
+ .imm = insn->imm,
+ .offset = insn->off,
+ };
+ const struct bpf_kfunc_desc *res;
+ struct bpf_kfunc_desc_tab *tab;
+
+ tab = prog->aux->kfunc_tab;
+ res = bsearch(&desc, tab->descs, tab->nr_descs,
+ sizeof(tab->descs[0]), kfunc_desc_cmp_by_imm_off);
+
+ return res ? &res->func_model : NULL;
+}
+
+static int add_subprog_and_kfunc(struct bpf_verifier_env *env)
+{
+ struct bpf_subprog_info *subprog = env->subprog_info;
+ struct bpf_insn *insn = env->prog->insnsi;
+ int i, ret, insn_cnt = env->prog->len;
+
+ /* Add entry function. */
+ ret = add_subprog(env, 0);
+ if (ret)
+ return ret;
+
+ for (i = 0; i < insn_cnt; i++, insn++) {
+ if (!bpf_pseudo_func(insn) && !bpf_pseudo_call(insn) &&
+ !bpf_pseudo_kfunc_call(insn))
+ continue;
+
+ if (!env->bpf_capable) {
+ verbose(env, "loading/calling other bpf or kernel functions are allowed for CAP_BPF and CAP_SYS_ADMIN\n");
+ return -EPERM;
+ }
+
+ if (bpf_pseudo_func(insn) || bpf_pseudo_call(insn))
+ ret = add_subprog(env, i + insn->imm + 1);
+ else
+ ret = add_kfunc_call(env, insn->imm, insn->off);
+
+ if (ret < 0)
+ return ret;
+ }
+
+ /* Add a fake 'exit' subprog which could simplify subprog iteration
+ * logic. 'subprog_cnt' should not be increased.
+ */
+ subprog[env->subprog_cnt].start = insn_cnt;
+
+ if (env->log.level & BPF_LOG_LEVEL2)
+ for (i = 0; i < env->subprog_cnt; i++)
+ verbose(env, "func#%d @%d\n", i, subprog[i].start);
+
+ return 0;
+}
+
+static int check_subprogs(struct bpf_verifier_env *env)
+{
+ int i, subprog_start, subprog_end, off, cur_subprog = 0;
+ struct bpf_subprog_info *subprog = env->subprog_info;
+ struct bpf_insn *insn = env->prog->insnsi;
+ int insn_cnt = env->prog->len;
+
+ /* now check that all jumps are within the same subprog */
+ subprog_start = subprog[cur_subprog].start;
+ subprog_end = subprog[cur_subprog + 1].start;
+ for (i = 0; i < insn_cnt; i++) {
+ u8 code = insn[i].code;
+
+ if (code == (BPF_JMP | BPF_CALL) &&
+ insn[i].src_reg == 0 &&
+ insn[i].imm == BPF_FUNC_tail_call)
+ subprog[cur_subprog].has_tail_call = true;
+ if (BPF_CLASS(code) == BPF_LD &&
+ (BPF_MODE(code) == BPF_ABS || BPF_MODE(code) == BPF_IND))
+ subprog[cur_subprog].has_ld_abs = true;
+ if (BPF_CLASS(code) != BPF_JMP && BPF_CLASS(code) != BPF_JMP32)
+ goto next;
+ if (BPF_OP(code) == BPF_EXIT || BPF_OP(code) == BPF_CALL)
+ goto next;
+ if (code == (BPF_JMP32 | BPF_JA))
+ off = i + insn[i].imm + 1;
+ else
+ off = i + insn[i].off + 1;
+ if (off < subprog_start || off >= subprog_end) {
+ verbose(env, "jump out of range from insn %d to %d\n", i, off);
+ return -EINVAL;
+ }
+next:
+ if (i == subprog_end - 1) {
+ /* to avoid fall-through from one subprog into another
+ * the last insn of the subprog should be either exit
+ * or unconditional jump back
+ */
+ if (code != (BPF_JMP | BPF_EXIT) &&
+ code != (BPF_JMP32 | BPF_JA) &&
+ code != (BPF_JMP | BPF_JA)) {
+ verbose(env, "last insn is not an exit or jmp\n");
+ return -EINVAL;
+ }
+ subprog_start = subprog_end;
+ cur_subprog++;
+ if (cur_subprog < env->subprog_cnt)
+ subprog_end = subprog[cur_subprog + 1].start;
+ }
+ }
+ return 0;
+}
+
+/* Parentage chain of this register (or stack slot) should take care of all
+ * issues like callee-saved registers, stack slot allocation time, etc.
+ */
+static int mark_reg_read(struct bpf_verifier_env *env,
+ const struct bpf_reg_state *state,
+ struct bpf_reg_state *parent, u8 flag)
+{
+ bool writes = parent == state->parent; /* Observe write marks */
+ int cnt = 0;
+
+ while (parent) {
+ /* if read wasn't screened by an earlier write ... */
+ if (writes && state->live & REG_LIVE_WRITTEN)
+ break;
+ if (parent->live & REG_LIVE_DONE) {
+ verbose(env, "verifier BUG type %s var_off %lld off %d\n",
+ reg_type_str(env, parent->type),
+ parent->var_off.value, parent->off);
+ return -EFAULT;
+ }
+ /* The first condition is more likely to be true than the
+ * second, checked it first.
+ */
+ if ((parent->live & REG_LIVE_READ) == flag ||
+ parent->live & REG_LIVE_READ64)
+ /* The parentage chain never changes and
+ * this parent was already marked as LIVE_READ.
+ * There is no need to keep walking the chain again and
+ * keep re-marking all parents as LIVE_READ.
+ * This case happens when the same register is read
+ * multiple times without writes into it in-between.
+ * Also, if parent has the stronger REG_LIVE_READ64 set,
+ * then no need to set the weak REG_LIVE_READ32.
+ */
+ break;
+ /* ... then we depend on parent's value */
+ parent->live |= flag;
+ /* REG_LIVE_READ64 overrides REG_LIVE_READ32. */
+ if (flag == REG_LIVE_READ64)
+ parent->live &= ~REG_LIVE_READ32;
+ state = parent;
+ parent = state->parent;
+ writes = true;
+ cnt++;
+ }
+
+ if (env->longest_mark_read_walk < cnt)
+ env->longest_mark_read_walk = cnt;
+ return 0;
+}
+
+static int mark_dynptr_read(struct bpf_verifier_env *env, struct bpf_reg_state *reg)
+{
+ struct bpf_func_state *state = func(env, reg);
+ int spi, ret;
+
+ /* For CONST_PTR_TO_DYNPTR, it must have already been done by
+ * check_reg_arg in check_helper_call and mark_btf_func_reg_size in
+ * check_kfunc_call.
+ */
+ if (reg->type == CONST_PTR_TO_DYNPTR)
+ return 0;
+ spi = dynptr_get_spi(env, reg);
+ if (spi < 0)
+ return spi;
+ /* Caller ensures dynptr is valid and initialized, which means spi is in
+ * bounds and spi is the first dynptr slot. Simply mark stack slot as
+ * read.
+ */
+ ret = mark_reg_read(env, &state->stack[spi].spilled_ptr,
+ state->stack[spi].spilled_ptr.parent, REG_LIVE_READ64);
+ if (ret)
+ return ret;
+ return mark_reg_read(env, &state->stack[spi - 1].spilled_ptr,
+ state->stack[spi - 1].spilled_ptr.parent, REG_LIVE_READ64);
+}
+
+static int mark_iter_read(struct bpf_verifier_env *env, struct bpf_reg_state *reg,
+ int spi, int nr_slots)
+{
+ struct bpf_func_state *state = func(env, reg);
+ int err, i;
+
+ for (i = 0; i < nr_slots; i++) {
+ struct bpf_reg_state *st = &state->stack[spi - i].spilled_ptr;
+
+ err = mark_reg_read(env, st, st->parent, REG_LIVE_READ64);
+ if (err)
+ return err;
+
+ mark_stack_slot_scratched(env, spi - i);
+ }
+
+ return 0;
+}
+
+/* This function is supposed to be used by the following 32-bit optimization
+ * code only. It returns TRUE if the source or destination register operates
+ * on 64-bit, otherwise return FALSE.
+ */
+static bool is_reg64(struct bpf_verifier_env *env, struct bpf_insn *insn,
+ u32 regno, struct bpf_reg_state *reg, enum reg_arg_type t)
+{
+ u8 code, class, op;
+
+ code = insn->code;
+ class = BPF_CLASS(code);
+ op = BPF_OP(code);
+ if (class == BPF_JMP) {
+ /* BPF_EXIT for "main" will reach here. Return TRUE
+ * conservatively.
+ */
+ if (op == BPF_EXIT)
+ return true;
+ if (op == BPF_CALL) {
+ /* BPF to BPF call will reach here because of marking
+ * caller saved clobber with DST_OP_NO_MARK for which we
+ * don't care the register def because they are anyway
+ * marked as NOT_INIT already.
+ */
+ if (insn->src_reg == BPF_PSEUDO_CALL)
+ return false;
+ /* Helper call will reach here because of arg type
+ * check, conservatively return TRUE.
+ */
+ if (t == SRC_OP)
+ return true;
+
+ return false;
+ }
+ }
+
+ if (class == BPF_ALU64 && op == BPF_END && (insn->imm == 16 || insn->imm == 32))
+ return false;
+
+ if (class == BPF_ALU64 || class == BPF_JMP ||
+ (class == BPF_ALU && op == BPF_END && insn->imm == 64))
+ return true;
+
+ if (class == BPF_ALU || class == BPF_JMP32)
+ return false;
+
+ if (class == BPF_LDX) {
+ if (t != SRC_OP)
+ return BPF_SIZE(code) == BPF_DW;
+ /* LDX source must be ptr. */
+ return true;
+ }
+
+ if (class == BPF_STX) {
+ /* BPF_STX (including atomic variants) has multiple source
+ * operands, one of which is a ptr. Check whether the caller is
+ * asking about it.
+ */
+ if (t == SRC_OP && reg->type != SCALAR_VALUE)
+ return true;
+ return BPF_SIZE(code) == BPF_DW;
+ }
+
+ if (class == BPF_LD) {
+ u8 mode = BPF_MODE(code);
+
+ /* LD_IMM64 */
+ if (mode == BPF_IMM)
+ return true;
+
+ /* Both LD_IND and LD_ABS return 32-bit data. */
+ if (t != SRC_OP)
+ return false;
+
+ /* Implicit ctx ptr. */
+ if (regno == BPF_REG_6)
+ return true;
+
+ /* Explicit source could be any width. */
+ return true;
+ }
+
+ if (class == BPF_ST)
+ /* The only source register for BPF_ST is a ptr. */
+ return true;
+
+ /* Conservatively return true at default. */
+ return true;
+}
+
+/* Return the regno defined by the insn, or -1. */
+static int insn_def_regno(const struct bpf_insn *insn)
+{
+ switch (BPF_CLASS(insn->code)) {
+ case BPF_JMP:
+ case BPF_JMP32:
+ case BPF_ST:
+ return -1;
+ case BPF_STX:
+ if (BPF_MODE(insn->code) == BPF_ATOMIC &&
+ (insn->imm & BPF_FETCH)) {
+ if (insn->imm == BPF_CMPXCHG)
+ return BPF_REG_0;
+ else
+ return insn->src_reg;
+ } else {
+ return -1;
+ }
+ default:
+ return insn->dst_reg;
+ }
+}
+
+/* Return TRUE if INSN has defined any 32-bit value explicitly. */
+static bool insn_has_def32(struct bpf_verifier_env *env, struct bpf_insn *insn)
+{
+ int dst_reg = insn_def_regno(insn);
+
+ if (dst_reg == -1)
+ return false;
+
+ return !is_reg64(env, insn, dst_reg, NULL, DST_OP);
+}
+
+static void mark_insn_zext(struct bpf_verifier_env *env,
+ struct bpf_reg_state *reg)
+{
+ s32 def_idx = reg->subreg_def;
+
+ if (def_idx == DEF_NOT_SUBREG)
+ return;
+
+ env->insn_aux_data[def_idx - 1].zext_dst = true;
+ /* The dst will be zero extended, so won't be sub-register anymore. */
+ reg->subreg_def = DEF_NOT_SUBREG;
+}
+
+static int __check_reg_arg(struct bpf_verifier_env *env, struct bpf_reg_state *regs, u32 regno,
+ enum reg_arg_type t)
+{
+ struct bpf_insn *insn = env->prog->insnsi + env->insn_idx;
+ struct bpf_reg_state *reg;
+ bool rw64;
+
+ if (regno >= MAX_BPF_REG) {
+ verbose(env, "R%d is invalid\n", regno);
+ return -EINVAL;
+ }
+
+ mark_reg_scratched(env, regno);
+
+ reg = &regs[regno];
+ rw64 = is_reg64(env, insn, regno, reg, t);
+ if (t == SRC_OP) {
+ /* check whether register used as source operand can be read */
+ if (reg->type == NOT_INIT) {
+ verbose(env, "R%d !read_ok\n", regno);
+ return -EACCES;
+ }
+ /* We don't need to worry about FP liveness because it's read-only */
+ if (regno == BPF_REG_FP)
+ return 0;
+
+ if (rw64)
+ mark_insn_zext(env, reg);
+
+ return mark_reg_read(env, reg, reg->parent,
+ rw64 ? REG_LIVE_READ64 : REG_LIVE_READ32);
+ } else {
+ /* check whether register used as dest operand can be written to */
+ if (regno == BPF_REG_FP) {
+ verbose(env, "frame pointer is read only\n");
+ return -EACCES;
+ }
+ reg->live |= REG_LIVE_WRITTEN;
+ reg->subreg_def = rw64 ? DEF_NOT_SUBREG : env->insn_idx + 1;
+ if (t == DST_OP)
+ mark_reg_unknown(env, regs, regno);
+ }
+ return 0;
+}
+
+static int check_reg_arg(struct bpf_verifier_env *env, u32 regno,
+ enum reg_arg_type t)
+{
+ struct bpf_verifier_state *vstate = env->cur_state;
+ struct bpf_func_state *state = vstate->frame[vstate->curframe];
+
+ return __check_reg_arg(env, state->regs, regno, t);
+}
+
+static void mark_jmp_point(struct bpf_verifier_env *env, int idx)
+{
+ env->insn_aux_data[idx].jmp_point = true;
+}
+
+static bool is_jmp_point(struct bpf_verifier_env *env, int insn_idx)
+{
+ return env->insn_aux_data[insn_idx].jmp_point;
+}
+
+/* for any branch, call, exit record the history of jmps in the given state */
+static int push_jmp_history(struct bpf_verifier_env *env,
+ struct bpf_verifier_state *cur)
+{
+ u32 cnt = cur->jmp_history_cnt;
+ struct bpf_idx_pair *p;
+ size_t alloc_size;
+
+ if (!is_jmp_point(env, env->insn_idx))
+ return 0;
+
+ cnt++;
+ alloc_size = kmalloc_size_roundup(size_mul(cnt, sizeof(*p)));
+ p = krealloc(cur->jmp_history, alloc_size, GFP_USER);
+ if (!p)
+ return -ENOMEM;
+ p[cnt - 1].idx = env->insn_idx;
+ p[cnt - 1].prev_idx = env->prev_insn_idx;
+ cur->jmp_history = p;
+ cur->jmp_history_cnt = cnt;
+ return 0;
+}
+
+/* Backtrack one insn at a time. If idx is not at the top of recorded
+ * history then previous instruction came from straight line execution.
+ * Return -ENOENT if we exhausted all instructions within given state.
+ *
+ * It's legal to have a bit of a looping with the same starting and ending
+ * insn index within the same state, e.g.: 3->4->5->3, so just because current
+ * instruction index is the same as state's first_idx doesn't mean we are
+ * done. If there is still some jump history left, we should keep going. We
+ * need to take into account that we might have a jump history between given
+ * state's parent and itself, due to checkpointing. In this case, we'll have
+ * history entry recording a jump from last instruction of parent state and
+ * first instruction of given state.
+ */
+static int get_prev_insn_idx(struct bpf_verifier_state *st, int i,
+ u32 *history)
+{
+ u32 cnt = *history;
+
+ if (i == st->first_insn_idx) {
+ if (cnt == 0)
+ return -ENOENT;
+ if (cnt == 1 && st->jmp_history[0].idx == i)
+ return -ENOENT;
+ }
+
+ if (cnt && st->jmp_history[cnt - 1].idx == i) {
+ i = st->jmp_history[cnt - 1].prev_idx;
+ (*history)--;
+ } else {
+ i--;
+ }
+ return i;
+}
+
+static const char *disasm_kfunc_name(void *data, const struct bpf_insn *insn)
+{
+ const struct btf_type *func;
+ struct btf *desc_btf;
+
+ if (insn->src_reg != BPF_PSEUDO_KFUNC_CALL)
+ return NULL;
+
+ desc_btf = find_kfunc_desc_btf(data, insn->off);
+ if (IS_ERR(desc_btf))
+ return "<error>";
+
+ func = btf_type_by_id(desc_btf, insn->imm);
+ return btf_name_by_offset(desc_btf, func->name_off);
+}
+
+static inline void bt_init(struct backtrack_state *bt, u32 frame)
+{
+ bt->frame = frame;
+}
+
+static inline void bt_reset(struct backtrack_state *bt)
+{
+ struct bpf_verifier_env *env = bt->env;
+
+ memset(bt, 0, sizeof(*bt));
+ bt->env = env;
+}
+
+static inline u32 bt_empty(struct backtrack_state *bt)
+{
+ u64 mask = 0;
+ int i;
+
+ for (i = 0; i <= bt->frame; i++)
+ mask |= bt->reg_masks[i] | bt->stack_masks[i];
+
+ return mask == 0;
+}
+
+static inline int bt_subprog_enter(struct backtrack_state *bt)
+{
+ if (bt->frame == MAX_CALL_FRAMES - 1) {
+ verbose(bt->env, "BUG subprog enter from frame %d\n", bt->frame);
+ WARN_ONCE(1, "verifier backtracking bug");
+ return -EFAULT;
+ }
+ bt->frame++;
+ return 0;
+}
+
+static inline int bt_subprog_exit(struct backtrack_state *bt)
+{
+ if (bt->frame == 0) {
+ verbose(bt->env, "BUG subprog exit from frame 0\n");
+ WARN_ONCE(1, "verifier backtracking bug");
+ return -EFAULT;
+ }
+ bt->frame--;
+ return 0;
+}
+
+static inline void bt_set_frame_reg(struct backtrack_state *bt, u32 frame, u32 reg)
+{
+ bt->reg_masks[frame] |= 1 << reg;
+}
+
+static inline void bt_clear_frame_reg(struct backtrack_state *bt, u32 frame, u32 reg)
+{
+ bt->reg_masks[frame] &= ~(1 << reg);
+}
+
+static inline void bt_set_reg(struct backtrack_state *bt, u32 reg)
+{
+ bt_set_frame_reg(bt, bt->frame, reg);
+}
+
+static inline void bt_clear_reg(struct backtrack_state *bt, u32 reg)
+{
+ bt_clear_frame_reg(bt, bt->frame, reg);
+}
+
+static inline void bt_set_frame_slot(struct backtrack_state *bt, u32 frame, u32 slot)
+{
+ bt->stack_masks[frame] |= 1ull << slot;
+}
+
+static inline void bt_clear_frame_slot(struct backtrack_state *bt, u32 frame, u32 slot)
+{
+ bt->stack_masks[frame] &= ~(1ull << slot);
+}
+
+static inline void bt_set_slot(struct backtrack_state *bt, u32 slot)
+{
+ bt_set_frame_slot(bt, bt->frame, slot);
+}
+
+static inline void bt_clear_slot(struct backtrack_state *bt, u32 slot)
+{
+ bt_clear_frame_slot(bt, bt->frame, slot);
+}
+
+static inline u32 bt_frame_reg_mask(struct backtrack_state *bt, u32 frame)
+{
+ return bt->reg_masks[frame];
+}
+
+static inline u32 bt_reg_mask(struct backtrack_state *bt)
+{
+ return bt->reg_masks[bt->frame];
+}
+
+static inline u64 bt_frame_stack_mask(struct backtrack_state *bt, u32 frame)
+{
+ return bt->stack_masks[frame];
+}
+
+static inline u64 bt_stack_mask(struct backtrack_state *bt)
+{
+ return bt->stack_masks[bt->frame];
+}
+
+static inline bool bt_is_reg_set(struct backtrack_state *bt, u32 reg)
+{
+ return bt->reg_masks[bt->frame] & (1 << reg);
+}
+
+static inline bool bt_is_slot_set(struct backtrack_state *bt, u32 slot)
+{
+ return bt->stack_masks[bt->frame] & (1ull << slot);
+}
+
+/* format registers bitmask, e.g., "r0,r2,r4" for 0x15 mask */
+static void fmt_reg_mask(char *buf, ssize_t buf_sz, u32 reg_mask)
+{
+ DECLARE_BITMAP(mask, 64);
+ bool first = true;
+ int i, n;
+
+ buf[0] = '\0';
+
+ bitmap_from_u64(mask, reg_mask);
+ for_each_set_bit(i, mask, 32) {
+ n = snprintf(buf, buf_sz, "%sr%d", first ? "" : ",", i);
+ first = false;
+ buf += n;
+ buf_sz -= n;
+ if (buf_sz < 0)
+ break;
+ }
+}
+/* format stack slots bitmask, e.g., "-8,-24,-40" for 0x15 mask */
+static void fmt_stack_mask(char *buf, ssize_t buf_sz, u64 stack_mask)
+{
+ DECLARE_BITMAP(mask, 64);
+ bool first = true;
+ int i, n;
+
+ buf[0] = '\0';
+
+ bitmap_from_u64(mask, stack_mask);
+ for_each_set_bit(i, mask, 64) {
+ n = snprintf(buf, buf_sz, "%s%d", first ? "" : ",", -(i + 1) * 8);
+ first = false;
+ buf += n;
+ buf_sz -= n;
+ if (buf_sz < 0)
+ break;
+ }
+}
+
+static bool calls_callback(struct bpf_verifier_env *env, int insn_idx);
+
+/* For given verifier state backtrack_insn() is called from the last insn to
+ * the first insn. Its purpose is to compute a bitmask of registers and
+ * stack slots that needs precision in the parent verifier state.
+ *
+ * @idx is an index of the instruction we are currently processing;
+ * @subseq_idx is an index of the subsequent instruction that:
+ * - *would be* executed next, if jump history is viewed in forward order;
+ * - *was* processed previously during backtracking.
+ */
+static int backtrack_insn(struct bpf_verifier_env *env, int idx, int subseq_idx,
+ struct backtrack_state *bt)
+{
+ const struct bpf_insn_cbs cbs = {
+ .cb_call = disasm_kfunc_name,
+ .cb_print = verbose,
+ .private_data = env,
+ };
+ struct bpf_insn *insn = env->prog->insnsi + idx;
+ u8 class = BPF_CLASS(insn->code);
+ u8 opcode = BPF_OP(insn->code);
+ u8 mode = BPF_MODE(insn->code);
+ u32 dreg = insn->dst_reg;
+ u32 sreg = insn->src_reg;
+ u32 spi, i;
+
+ if (insn->code == 0)
+ return 0;
+ if (env->log.level & BPF_LOG_LEVEL2) {
+ fmt_reg_mask(env->tmp_str_buf, TMP_STR_BUF_LEN, bt_reg_mask(bt));
+ verbose(env, "mark_precise: frame%d: regs=%s ",
+ bt->frame, env->tmp_str_buf);
+ fmt_stack_mask(env->tmp_str_buf, TMP_STR_BUF_LEN, bt_stack_mask(bt));
+ verbose(env, "stack=%s before ", env->tmp_str_buf);
+ verbose(env, "%d: ", idx);
+ print_bpf_insn(&cbs, insn, env->allow_ptr_leaks);
+ }
+
+ if (class == BPF_ALU || class == BPF_ALU64) {
+ if (!bt_is_reg_set(bt, dreg))
+ return 0;
+ if (opcode == BPF_END || opcode == BPF_NEG) {
+ /* sreg is reserved and unused
+ * dreg still need precision before this insn
+ */
+ return 0;
+ } else if (opcode == BPF_MOV) {
+ if (BPF_SRC(insn->code) == BPF_X) {
+ /* dreg = sreg or dreg = (s8, s16, s32)sreg
+ * dreg needs precision after this insn
+ * sreg needs precision before this insn
+ */
+ bt_clear_reg(bt, dreg);
+ bt_set_reg(bt, sreg);
+ } else {
+ /* dreg = K
+ * dreg needs precision after this insn.
+ * Corresponding register is already marked
+ * as precise=true in this verifier state.
+ * No further markings in parent are necessary
+ */
+ bt_clear_reg(bt, dreg);
+ }
+ } else {
+ if (BPF_SRC(insn->code) == BPF_X) {
+ /* dreg += sreg
+ * both dreg and sreg need precision
+ * before this insn
+ */
+ bt_set_reg(bt, sreg);
+ } /* else dreg += K
+ * dreg still needs precision before this insn
+ */
+ }
+ } else if (class == BPF_LDX) {
+ if (!bt_is_reg_set(bt, dreg))
+ return 0;
+ bt_clear_reg(bt, dreg);
+
+ /* scalars can only be spilled into stack w/o losing precision.
+ * Load from any other memory can be zero extended.
+ * The desire to keep that precision is already indicated
+ * by 'precise' mark in corresponding register of this state.
+ * No further tracking necessary.
+ */
+ if (insn->src_reg != BPF_REG_FP)
+ return 0;
+
+ /* dreg = *(u64 *)[fp - off] was a fill from the stack.
+ * that [fp - off] slot contains scalar that needs to be
+ * tracked with precision
+ */
+ spi = (-insn->off - 1) / BPF_REG_SIZE;
+ if (spi >= 64) {
+ verbose(env, "BUG spi %d\n", spi);
+ WARN_ONCE(1, "verifier backtracking bug");
+ return -EFAULT;
+ }
+ bt_set_slot(bt, spi);
+ } else if (class == BPF_STX || class == BPF_ST) {
+ if (bt_is_reg_set(bt, dreg))
+ /* stx & st shouldn't be using _scalar_ dst_reg
+ * to access memory. It means backtracking
+ * encountered a case of pointer subtraction.
+ */
+ return -ENOTSUPP;
+ /* scalars can only be spilled into stack */
+ if (insn->dst_reg != BPF_REG_FP)
+ return 0;
+ spi = (-insn->off - 1) / BPF_REG_SIZE;
+ if (spi >= 64) {
+ verbose(env, "BUG spi %d\n", spi);
+ WARN_ONCE(1, "verifier backtracking bug");
+ return -EFAULT;
+ }
+ if (!bt_is_slot_set(bt, spi))
+ return 0;
+ bt_clear_slot(bt, spi);
+ if (class == BPF_STX)
+ bt_set_reg(bt, sreg);
+ } else if (class == BPF_JMP || class == BPF_JMP32) {
+ if (bpf_pseudo_call(insn)) {
+ int subprog_insn_idx, subprog;
+
+ subprog_insn_idx = idx + insn->imm + 1;
+ subprog = find_subprog(env, subprog_insn_idx);
+ if (subprog < 0)
+ return -EFAULT;
+
+ if (subprog_is_global(env, subprog)) {
+ /* check that jump history doesn't have any
+ * extra instructions from subprog; the next
+ * instruction after call to global subprog
+ * should be literally next instruction in
+ * caller program
+ */
+ WARN_ONCE(idx + 1 != subseq_idx, "verifier backtracking bug");
+ /* r1-r5 are invalidated after subprog call,
+ * so for global func call it shouldn't be set
+ * anymore
+ */
+ if (bt_reg_mask(bt) & BPF_REGMASK_ARGS) {
+ verbose(env, "BUG regs %x\n", bt_reg_mask(bt));
+ WARN_ONCE(1, "verifier backtracking bug");
+ return -EFAULT;
+ }
+ /* global subprog always sets R0 */
+ bt_clear_reg(bt, BPF_REG_0);
+ return 0;
+ } else {
+ /* static subprog call instruction, which
+ * means that we are exiting current subprog,
+ * so only r1-r5 could be still requested as
+ * precise, r0 and r6-r10 or any stack slot in
+ * the current frame should be zero by now
+ */
+ if (bt_reg_mask(bt) & ~BPF_REGMASK_ARGS) {
+ verbose(env, "BUG regs %x\n", bt_reg_mask(bt));
+ WARN_ONCE(1, "verifier backtracking bug");
+ return -EFAULT;
+ }
+ /* we don't track register spills perfectly,
+ * so fallback to force-precise instead of failing */
+ if (bt_stack_mask(bt) != 0)
+ return -ENOTSUPP;
+ /* propagate r1-r5 to the caller */
+ for (i = BPF_REG_1; i <= BPF_REG_5; i++) {
+ if (bt_is_reg_set(bt, i)) {
+ bt_clear_reg(bt, i);
+ bt_set_frame_reg(bt, bt->frame - 1, i);
+ }
+ }
+ if (bt_subprog_exit(bt))
+ return -EFAULT;
+ return 0;
+ }
+ } else if (is_sync_callback_calling_insn(insn) && idx != subseq_idx - 1) {
+ /* exit from callback subprog to callback-calling helper or
+ * kfunc call. Use idx/subseq_idx check to discern it from
+ * straight line code backtracking.
+ * Unlike the subprog call handling above, we shouldn't
+ * propagate precision of r1-r5 (if any requested), as they are
+ * not actually arguments passed directly to callback subprogs
+ */
+ if (bt_reg_mask(bt) & ~BPF_REGMASK_ARGS) {
+ verbose(env, "BUG regs %x\n", bt_reg_mask(bt));
+ WARN_ONCE(1, "verifier backtracking bug");
+ return -EFAULT;
+ }
+ if (bt_stack_mask(bt) != 0)
+ return -ENOTSUPP;
+ /* clear r1-r5 in callback subprog's mask */
+ for (i = BPF_REG_1; i <= BPF_REG_5; i++)
+ bt_clear_reg(bt, i);
+ if (bt_subprog_exit(bt))
+ return -EFAULT;
+ return 0;
+ } else if (opcode == BPF_CALL) {
+ /* kfunc with imm==0 is invalid and fixup_kfunc_call will
+ * catch this error later. Make backtracking conservative
+ * with ENOTSUPP.
+ */
+ if (insn->src_reg == BPF_PSEUDO_KFUNC_CALL && insn->imm == 0)
+ return -ENOTSUPP;
+ /* regular helper call sets R0 */
+ bt_clear_reg(bt, BPF_REG_0);
+ if (bt_reg_mask(bt) & BPF_REGMASK_ARGS) {
+ /* if backtracing was looking for registers R1-R5
+ * they should have been found already.
+ */
+ verbose(env, "BUG regs %x\n", bt_reg_mask(bt));
+ WARN_ONCE(1, "verifier backtracking bug");
+ return -EFAULT;
+ }
+ } else if (opcode == BPF_EXIT) {
+ bool r0_precise;
+
+ /* Backtracking to a nested function call, 'idx' is a part of
+ * the inner frame 'subseq_idx' is a part of the outer frame.
+ * In case of a regular function call, instructions giving
+ * precision to registers R1-R5 should have been found already.
+ * In case of a callback, it is ok to have R1-R5 marked for
+ * backtracking, as these registers are set by the function
+ * invoking callback.
+ */
+ if (subseq_idx >= 0 && calls_callback(env, subseq_idx))
+ for (i = BPF_REG_1; i <= BPF_REG_5; i++)
+ bt_clear_reg(bt, i);
+ if (bt_reg_mask(bt) & BPF_REGMASK_ARGS) {
+ verbose(env, "BUG regs %x\n", bt_reg_mask(bt));
+ WARN_ONCE(1, "verifier backtracking bug");
+ return -EFAULT;
+ }
+
+ /* BPF_EXIT in subprog or callback always returns
+ * right after the call instruction, so by checking
+ * whether the instruction at subseq_idx-1 is subprog
+ * call or not we can distinguish actual exit from
+ * *subprog* from exit from *callback*. In the former
+ * case, we need to propagate r0 precision, if
+ * necessary. In the former we never do that.
+ */
+ r0_precise = subseq_idx - 1 >= 0 &&
+ bpf_pseudo_call(&env->prog->insnsi[subseq_idx - 1]) &&
+ bt_is_reg_set(bt, BPF_REG_0);
+
+ bt_clear_reg(bt, BPF_REG_0);
+ if (bt_subprog_enter(bt))
+ return -EFAULT;
+
+ if (r0_precise)
+ bt_set_reg(bt, BPF_REG_0);
+ /* r6-r9 and stack slots will stay set in caller frame
+ * bitmasks until we return back from callee(s)
+ */
+ return 0;
+ } else if (BPF_SRC(insn->code) == BPF_X) {
+ if (!bt_is_reg_set(bt, dreg) && !bt_is_reg_set(bt, sreg))
+ return 0;
+ /* dreg <cond> sreg
+ * Both dreg and sreg need precision before
+ * this insn. If only sreg was marked precise
+ * before it would be equally necessary to
+ * propagate it to dreg.
+ */
+ bt_set_reg(bt, dreg);
+ bt_set_reg(bt, sreg);
+ /* else dreg <cond> K
+ * Only dreg still needs precision before
+ * this insn, so for the K-based conditional
+ * there is nothing new to be marked.
+ */
+ }
+ } else if (class == BPF_LD) {
+ if (!bt_is_reg_set(bt, dreg))
+ return 0;
+ bt_clear_reg(bt, dreg);
+ /* It's ld_imm64 or ld_abs or ld_ind.
+ * For ld_imm64 no further tracking of precision
+ * into parent is necessary
+ */
+ if (mode == BPF_IND || mode == BPF_ABS)
+ /* to be analyzed */
+ return -ENOTSUPP;
+ }
+ return 0;
+}
+
+/* the scalar precision tracking algorithm:
+ * . at the start all registers have precise=false.
+ * . scalar ranges are tracked as normal through alu and jmp insns.
+ * . once precise value of the scalar register is used in:
+ * . ptr + scalar alu
+ * . if (scalar cond K|scalar)
+ * . helper_call(.., scalar, ...) where ARG_CONST is expected
+ * backtrack through the verifier states and mark all registers and
+ * stack slots with spilled constants that these scalar regisers
+ * should be precise.
+ * . during state pruning two registers (or spilled stack slots)
+ * are equivalent if both are not precise.
+ *
+ * Note the verifier cannot simply walk register parentage chain,
+ * since many different registers and stack slots could have been
+ * used to compute single precise scalar.
+ *
+ * The approach of starting with precise=true for all registers and then
+ * backtrack to mark a register as not precise when the verifier detects
+ * that program doesn't care about specific value (e.g., when helper
+ * takes register as ARG_ANYTHING parameter) is not safe.
+ *
+ * It's ok to walk single parentage chain of the verifier states.
+ * It's possible that this backtracking will go all the way till 1st insn.
+ * All other branches will be explored for needing precision later.
+ *
+ * The backtracking needs to deal with cases like:
+ * R8=map_value(id=0,off=0,ks=4,vs=1952,imm=0) R9_w=map_value(id=0,off=40,ks=4,vs=1952,imm=0)
+ * r9 -= r8
+ * r5 = r9
+ * if r5 > 0x79f goto pc+7
+ * R5_w=inv(id=0,umax_value=1951,var_off=(0x0; 0x7ff))
+ * r5 += 1
+ * ...
+ * call bpf_perf_event_output#25
+ * where .arg5_type = ARG_CONST_SIZE_OR_ZERO
+ *
+ * and this case:
+ * r6 = 1
+ * call foo // uses callee's r6 inside to compute r0
+ * r0 += r6
+ * if r0 == 0 goto
+ *
+ * to track above reg_mask/stack_mask needs to be independent for each frame.
+ *
+ * Also if parent's curframe > frame where backtracking started,
+ * the verifier need to mark registers in both frames, otherwise callees
+ * may incorrectly prune callers. This is similar to
+ * commit 7640ead93924 ("bpf: verifier: make sure callees don't prune with caller differences")
+ *
+ * For now backtracking falls back into conservative marking.
+ */
+static void mark_all_scalars_precise(struct bpf_verifier_env *env,
+ struct bpf_verifier_state *st)
+{
+ struct bpf_func_state *func;
+ struct bpf_reg_state *reg;
+ int i, j;
+
+ if (env->log.level & BPF_LOG_LEVEL2) {
+ verbose(env, "mark_precise: frame%d: falling back to forcing all scalars precise\n",
+ st->curframe);
+ }
+
+ /* big hammer: mark all scalars precise in this path.
+ * pop_stack may still get !precise scalars.
+ * We also skip current state and go straight to first parent state,
+ * because precision markings in current non-checkpointed state are
+ * not needed. See why in the comment in __mark_chain_precision below.
+ */
+ for (st = st->parent; st; st = st->parent) {
+ for (i = 0; i <= st->curframe; i++) {
+ func = st->frame[i];
+ for (j = 0; j < BPF_REG_FP; j++) {
+ reg = &func->regs[j];
+ if (reg->type != SCALAR_VALUE || reg->precise)
+ continue;
+ reg->precise = true;
+ if (env->log.level & BPF_LOG_LEVEL2) {
+ verbose(env, "force_precise: frame%d: forcing r%d to be precise\n",
+ i, j);
+ }
+ }
+ for (j = 0; j < func->allocated_stack / BPF_REG_SIZE; j++) {
+ if (!is_spilled_reg(&func->stack[j]))
+ continue;
+ reg = &func->stack[j].spilled_ptr;
+ if (reg->type != SCALAR_VALUE || reg->precise)
+ continue;
+ reg->precise = true;
+ if (env->log.level & BPF_LOG_LEVEL2) {
+ verbose(env, "force_precise: frame%d: forcing fp%d to be precise\n",
+ i, -(j + 1) * 8);
+ }
+ }
+ }
+ }
+}
+
+static void mark_all_scalars_imprecise(struct bpf_verifier_env *env, struct bpf_verifier_state *st)
+{
+ struct bpf_func_state *func;
+ struct bpf_reg_state *reg;
+ int i, j;
+
+ for (i = 0; i <= st->curframe; i++) {
+ func = st->frame[i];
+ for (j = 0; j < BPF_REG_FP; j++) {
+ reg = &func->regs[j];
+ if (reg->type != SCALAR_VALUE)
+ continue;
+ reg->precise = false;
+ }
+ for (j = 0; j < func->allocated_stack / BPF_REG_SIZE; j++) {
+ if (!is_spilled_reg(&func->stack[j]))
+ continue;
+ reg = &func->stack[j].spilled_ptr;
+ if (reg->type != SCALAR_VALUE)
+ continue;
+ reg->precise = false;
+ }
+ }
+}
+
+static bool idset_contains(struct bpf_idset *s, u32 id)
+{
+ u32 i;
+
+ for (i = 0; i < s->count; ++i)
+ if (s->ids[i] == id)
+ return true;
+
+ return false;
+}
+
+static int idset_push(struct bpf_idset *s, u32 id)
+{
+ if (WARN_ON_ONCE(s->count >= ARRAY_SIZE(s->ids)))
+ return -EFAULT;
+ s->ids[s->count++] = id;
+ return 0;
+}
+
+static void idset_reset(struct bpf_idset *s)
+{
+ s->count = 0;
+}
+
+/* Collect a set of IDs for all registers currently marked as precise in env->bt.
+ * Mark all registers with these IDs as precise.
+ */
+static int mark_precise_scalar_ids(struct bpf_verifier_env *env, struct bpf_verifier_state *st)
+{
+ struct bpf_idset *precise_ids = &env->idset_scratch;
+ struct backtrack_state *bt = &env->bt;
+ struct bpf_func_state *func;
+ struct bpf_reg_state *reg;
+ DECLARE_BITMAP(mask, 64);
+ int i, fr;
+
+ idset_reset(precise_ids);
+
+ for (fr = bt->frame; fr >= 0; fr--) {
+ func = st->frame[fr];
+
+ bitmap_from_u64(mask, bt_frame_reg_mask(bt, fr));
+ for_each_set_bit(i, mask, 32) {
+ reg = &func->regs[i];
+ if (!reg->id || reg->type != SCALAR_VALUE)
+ continue;
+ if (idset_push(precise_ids, reg->id))
+ return -EFAULT;
+ }
+
+ bitmap_from_u64(mask, bt_frame_stack_mask(bt, fr));
+ for_each_set_bit(i, mask, 64) {
+ if (i >= func->allocated_stack / BPF_REG_SIZE)
+ break;
+ if (!is_spilled_scalar_reg(&func->stack[i]))
+ continue;
+ reg = &func->stack[i].spilled_ptr;
+ if (!reg->id)
+ continue;
+ if (idset_push(precise_ids, reg->id))
+ return -EFAULT;
+ }
+ }
+
+ for (fr = 0; fr <= st->curframe; ++fr) {
+ func = st->frame[fr];
+
+ for (i = BPF_REG_0; i < BPF_REG_10; ++i) {
+ reg = &func->regs[i];
+ if (!reg->id)
+ continue;
+ if (!idset_contains(precise_ids, reg->id))
+ continue;
+ bt_set_frame_reg(bt, fr, i);
+ }
+ for (i = 0; i < func->allocated_stack / BPF_REG_SIZE; ++i) {
+ if (!is_spilled_scalar_reg(&func->stack[i]))
+ continue;
+ reg = &func->stack[i].spilled_ptr;
+ if (!reg->id)
+ continue;
+ if (!idset_contains(precise_ids, reg->id))
+ continue;
+ bt_set_frame_slot(bt, fr, i);
+ }
+ }
+
+ return 0;
+}
+
+/*
+ * __mark_chain_precision() backtracks BPF program instruction sequence and
+ * chain of verifier states making sure that register *regno* (if regno >= 0)
+ * and/or stack slot *spi* (if spi >= 0) are marked as precisely tracked
+ * SCALARS, as well as any other registers and slots that contribute to
+ * a tracked state of given registers/stack slots, depending on specific BPF
+ * assembly instructions (see backtrack_insns() for exact instruction handling
+ * logic). This backtracking relies on recorded jmp_history and is able to
+ * traverse entire chain of parent states. This process ends only when all the
+ * necessary registers/slots and their transitive dependencies are marked as
+ * precise.
+ *
+ * One important and subtle aspect is that precise marks *do not matter* in
+ * the currently verified state (current state). It is important to understand
+ * why this is the case.
+ *
+ * First, note that current state is the state that is not yet "checkpointed",
+ * i.e., it is not yet put into env->explored_states, and it has no children
+ * states as well. It's ephemeral, and can end up either a) being discarded if
+ * compatible explored state is found at some point or BPF_EXIT instruction is
+ * reached or b) checkpointed and put into env->explored_states, branching out
+ * into one or more children states.
+ *
+ * In the former case, precise markings in current state are completely
+ * ignored by state comparison code (see regsafe() for details). Only
+ * checkpointed ("old") state precise markings are important, and if old
+ * state's register/slot is precise, regsafe() assumes current state's
+ * register/slot as precise and checks value ranges exactly and precisely. If
+ * states turn out to be compatible, current state's necessary precise
+ * markings and any required parent states' precise markings are enforced
+ * after the fact with propagate_precision() logic, after the fact. But it's
+ * important to realize that in this case, even after marking current state
+ * registers/slots as precise, we immediately discard current state. So what
+ * actually matters is any of the precise markings propagated into current
+ * state's parent states, which are always checkpointed (due to b) case above).
+ * As such, for scenario a) it doesn't matter if current state has precise
+ * markings set or not.
+ *
+ * Now, for the scenario b), checkpointing and forking into child(ren)
+ * state(s). Note that before current state gets to checkpointing step, any
+ * processed instruction always assumes precise SCALAR register/slot
+ * knowledge: if precise value or range is useful to prune jump branch, BPF
+ * verifier takes this opportunity enthusiastically. Similarly, when
+ * register's value is used to calculate offset or memory address, exact
+ * knowledge of SCALAR range is assumed, checked, and enforced. So, similar to
+ * what we mentioned above about state comparison ignoring precise markings
+ * during state comparison, BPF verifier ignores and also assumes precise
+ * markings *at will* during instruction verification process. But as verifier
+ * assumes precision, it also propagates any precision dependencies across
+ * parent states, which are not yet finalized, so can be further restricted
+ * based on new knowledge gained from restrictions enforced by their children
+ * states. This is so that once those parent states are finalized, i.e., when
+ * they have no more active children state, state comparison logic in
+ * is_state_visited() would enforce strict and precise SCALAR ranges, if
+ * required for correctness.
+ *
+ * To build a bit more intuition, note also that once a state is checkpointed,
+ * the path we took to get to that state is not important. This is crucial
+ * property for state pruning. When state is checkpointed and finalized at
+ * some instruction index, it can be correctly and safely used to "short
+ * circuit" any *compatible* state that reaches exactly the same instruction
+ * index. I.e., if we jumped to that instruction from a completely different
+ * code path than original finalized state was derived from, it doesn't
+ * matter, current state can be discarded because from that instruction
+ * forward having a compatible state will ensure we will safely reach the
+ * exit. States describe preconditions for further exploration, but completely
+ * forget the history of how we got here.
+ *
+ * This also means that even if we needed precise SCALAR range to get to
+ * finalized state, but from that point forward *that same* SCALAR register is
+ * never used in a precise context (i.e., it's precise value is not needed for
+ * correctness), it's correct and safe to mark such register as "imprecise"
+ * (i.e., precise marking set to false). This is what we rely on when we do
+ * not set precise marking in current state. If no child state requires
+ * precision for any given SCALAR register, it's safe to dictate that it can
+ * be imprecise. If any child state does require this register to be precise,
+ * we'll mark it precise later retroactively during precise markings
+ * propagation from child state to parent states.
+ *
+ * Skipping precise marking setting in current state is a mild version of
+ * relying on the above observation. But we can utilize this property even
+ * more aggressively by proactively forgetting any precise marking in the
+ * current state (which we inherited from the parent state), right before we
+ * checkpoint it and branch off into new child state. This is done by
+ * mark_all_scalars_imprecise() to hopefully get more permissive and generic
+ * finalized states which help in short circuiting more future states.
+ */
+static int __mark_chain_precision(struct bpf_verifier_env *env, int regno)
+{
+ struct backtrack_state *bt = &env->bt;
+ struct bpf_verifier_state *st = env->cur_state;
+ int first_idx = st->first_insn_idx;
+ int last_idx = env->insn_idx;
+ int subseq_idx = -1;
+ struct bpf_func_state *func;
+ struct bpf_reg_state *reg;
+ bool skip_first = true;
+ int i, fr, err;
+
+ if (!env->bpf_capable)
+ return 0;
+
+ /* set frame number from which we are starting to backtrack */
+ bt_init(bt, env->cur_state->curframe);
+
+ /* Do sanity checks against current state of register and/or stack
+ * slot, but don't set precise flag in current state, as precision
+ * tracking in the current state is unnecessary.
+ */
+ func = st->frame[bt->frame];
+ if (regno >= 0) {
+ reg = &func->regs[regno];
+ if (reg->type != SCALAR_VALUE) {
+ WARN_ONCE(1, "backtracing misuse");
+ return -EFAULT;
+ }
+ bt_set_reg(bt, regno);
+ }
+
+ if (bt_empty(bt))
+ return 0;
+
+ for (;;) {
+ DECLARE_BITMAP(mask, 64);
+ u32 history = st->jmp_history_cnt;
+
+ if (env->log.level & BPF_LOG_LEVEL2) {
+ verbose(env, "mark_precise: frame%d: last_idx %d first_idx %d subseq_idx %d \n",
+ bt->frame, last_idx, first_idx, subseq_idx);
+ }
+
+ /* If some register with scalar ID is marked as precise,
+ * make sure that all registers sharing this ID are also precise.
+ * This is needed to estimate effect of find_equal_scalars().
+ * Do this at the last instruction of each state,
+ * bpf_reg_state::id fields are valid for these instructions.
+ *
+ * Allows to track precision in situation like below:
+ *
+ * r2 = unknown value
+ * ...
+ * --- state #0 ---
+ * ...
+ * r1 = r2 // r1 and r2 now share the same ID
+ * ...
+ * --- state #1 {r1.id = A, r2.id = A} ---
+ * ...
+ * if (r2 > 10) goto exit; // find_equal_scalars() assigns range to r1
+ * ...
+ * --- state #2 {r1.id = A, r2.id = A} ---
+ * r3 = r10
+ * r3 += r1 // need to mark both r1 and r2
+ */
+ if (mark_precise_scalar_ids(env, st))
+ return -EFAULT;
+
+ if (last_idx < 0) {
+ /* we are at the entry into subprog, which
+ * is expected for global funcs, but only if
+ * requested precise registers are R1-R5
+ * (which are global func's input arguments)
+ */
+ if (st->curframe == 0 &&
+ st->frame[0]->subprogno > 0 &&
+ st->frame[0]->callsite == BPF_MAIN_FUNC &&
+ bt_stack_mask(bt) == 0 &&
+ (bt_reg_mask(bt) & ~BPF_REGMASK_ARGS) == 0) {
+ bitmap_from_u64(mask, bt_reg_mask(bt));
+ for_each_set_bit(i, mask, 32) {
+ reg = &st->frame[0]->regs[i];
+ bt_clear_reg(bt, i);
+ if (reg->type == SCALAR_VALUE)
+ reg->precise = true;
+ }
+ return 0;
+ }
+
+ verbose(env, "BUG backtracking func entry subprog %d reg_mask %x stack_mask %llx\n",
+ st->frame[0]->subprogno, bt_reg_mask(bt), bt_stack_mask(bt));
+ WARN_ONCE(1, "verifier backtracking bug");
+ return -EFAULT;
+ }
+
+ for (i = last_idx;;) {
+ if (skip_first) {
+ err = 0;
+ skip_first = false;
+ } else {
+ err = backtrack_insn(env, i, subseq_idx, bt);
+ }
+ if (err == -ENOTSUPP) {
+ mark_all_scalars_precise(env, env->cur_state);
+ bt_reset(bt);
+ return 0;
+ } else if (err) {
+ return err;
+ }
+ if (bt_empty(bt))
+ /* Found assignment(s) into tracked register in this state.
+ * Since this state is already marked, just return.
+ * Nothing to be tracked further in the parent state.
+ */
+ return 0;
+ subseq_idx = i;
+ i = get_prev_insn_idx(st, i, &history);
+ if (i == -ENOENT)
+ break;
+ if (i >= env->prog->len) {
+ /* This can happen if backtracking reached insn 0
+ * and there are still reg_mask or stack_mask
+ * to backtrack.
+ * It means the backtracking missed the spot where
+ * particular register was initialized with a constant.
+ */
+ verbose(env, "BUG backtracking idx %d\n", i);
+ WARN_ONCE(1, "verifier backtracking bug");
+ return -EFAULT;
+ }
+ }
+ st = st->parent;
+ if (!st)
+ break;
+
+ for (fr = bt->frame; fr >= 0; fr--) {
+ func = st->frame[fr];
+ bitmap_from_u64(mask, bt_frame_reg_mask(bt, fr));
+ for_each_set_bit(i, mask, 32) {
+ reg = &func->regs[i];
+ if (reg->type != SCALAR_VALUE) {
+ bt_clear_frame_reg(bt, fr, i);
+ continue;
+ }
+ if (reg->precise)
+ bt_clear_frame_reg(bt, fr, i);
+ else
+ reg->precise = true;
+ }
+
+ bitmap_from_u64(mask, bt_frame_stack_mask(bt, fr));
+ for_each_set_bit(i, mask, 64) {
+ if (i >= func->allocated_stack / BPF_REG_SIZE) {
+ /* the sequence of instructions:
+ * 2: (bf) r3 = r10
+ * 3: (7b) *(u64 *)(r3 -8) = r0
+ * 4: (79) r4 = *(u64 *)(r10 -8)
+ * doesn't contain jmps. It's backtracked
+ * as a single block.
+ * During backtracking insn 3 is not recognized as
+ * stack access, so at the end of backtracking
+ * stack slot fp-8 is still marked in stack_mask.
+ * However the parent state may not have accessed
+ * fp-8 and it's "unallocated" stack space.
+ * In such case fallback to conservative.
+ */
+ mark_all_scalars_precise(env, env->cur_state);
+ bt_reset(bt);
+ return 0;
+ }
+
+ if (!is_spilled_scalar_reg(&func->stack[i])) {
+ bt_clear_frame_slot(bt, fr, i);
+ continue;
+ }
+ reg = &func->stack[i].spilled_ptr;
+ if (reg->precise)
+ bt_clear_frame_slot(bt, fr, i);
+ else
+ reg->precise = true;
+ }
+ if (env->log.level & BPF_LOG_LEVEL2) {
+ fmt_reg_mask(env->tmp_str_buf, TMP_STR_BUF_LEN,
+ bt_frame_reg_mask(bt, fr));
+ verbose(env, "mark_precise: frame%d: parent state regs=%s ",
+ fr, env->tmp_str_buf);
+ fmt_stack_mask(env->tmp_str_buf, TMP_STR_BUF_LEN,
+ bt_frame_stack_mask(bt, fr));
+ verbose(env, "stack=%s: ", env->tmp_str_buf);
+ print_verifier_state(env, func, true);
+ }
+ }
+
+ if (bt_empty(bt))
+ return 0;
+
+ subseq_idx = first_idx;
+ last_idx = st->last_insn_idx;
+ first_idx = st->first_insn_idx;
+ }
+
+ /* if we still have requested precise regs or slots, we missed
+ * something (e.g., stack access through non-r10 register), so
+ * fallback to marking all precise
+ */
+ if (!bt_empty(bt)) {
+ mark_all_scalars_precise(env, env->cur_state);
+ bt_reset(bt);
+ }
+
+ return 0;
+}
+
+int mark_chain_precision(struct bpf_verifier_env *env, int regno)
+{
+ return __mark_chain_precision(env, regno);
+}
+
+/* mark_chain_precision_batch() assumes that env->bt is set in the caller to
+ * desired reg and stack masks across all relevant frames
+ */
+static int mark_chain_precision_batch(struct bpf_verifier_env *env)
+{
+ return __mark_chain_precision(env, -1);
+}
+
+static bool is_spillable_regtype(enum bpf_reg_type type)
+{
+ switch (base_type(type)) {
+ case PTR_TO_MAP_VALUE:
+ case PTR_TO_STACK:
+ case PTR_TO_CTX:
+ case PTR_TO_PACKET:
+ case PTR_TO_PACKET_META:
+ case PTR_TO_PACKET_END:
+ case PTR_TO_FLOW_KEYS:
+ case CONST_PTR_TO_MAP:
+ case PTR_TO_SOCKET:
+ case PTR_TO_SOCK_COMMON:
+ case PTR_TO_TCP_SOCK:
+ case PTR_TO_XDP_SOCK:
+ case PTR_TO_BTF_ID:
+ case PTR_TO_BUF:
+ case PTR_TO_MEM:
+ case PTR_TO_FUNC:
+ case PTR_TO_MAP_KEY:
+ return true;
+ default:
+ return false;
+ }
+}
+
+/* Does this register contain a constant zero? */
+static bool register_is_null(struct bpf_reg_state *reg)
+{
+ return reg->type == SCALAR_VALUE && tnum_equals_const(reg->var_off, 0);
+}
+
+static bool register_is_const(struct bpf_reg_state *reg)
+{
+ return reg->type == SCALAR_VALUE && tnum_is_const(reg->var_off);
+}
+
+static bool __is_scalar_unbounded(struct bpf_reg_state *reg)
+{
+ return tnum_is_unknown(reg->var_off) &&
+ reg->smin_value == S64_MIN && reg->smax_value == S64_MAX &&
+ reg->umin_value == 0 && reg->umax_value == U64_MAX &&
+ reg->s32_min_value == S32_MIN && reg->s32_max_value == S32_MAX &&
+ reg->u32_min_value == 0 && reg->u32_max_value == U32_MAX;
+}
+
+static bool register_is_bounded(struct bpf_reg_state *reg)
+{
+ return reg->type == SCALAR_VALUE && !__is_scalar_unbounded(reg);
+}
+
+static bool __is_pointer_value(bool allow_ptr_leaks,
+ const struct bpf_reg_state *reg)
+{
+ if (allow_ptr_leaks)
+ return false;
+
+ return reg->type != SCALAR_VALUE;
+}
+
+/* Copy src state preserving dst->parent and dst->live fields */
+static void copy_register_state(struct bpf_reg_state *dst, const struct bpf_reg_state *src)
+{
+ struct bpf_reg_state *parent = dst->parent;
+ enum bpf_reg_liveness live = dst->live;
+
+ *dst = *src;
+ dst->parent = parent;
+ dst->live = live;
+}
+
+static void save_register_state(struct bpf_func_state *state,
+ int spi, struct bpf_reg_state *reg,
+ int size)
+{
+ int i;
+
+ copy_register_state(&state->stack[spi].spilled_ptr, reg);
+ if (size == BPF_REG_SIZE)
+ state->stack[spi].spilled_ptr.live |= REG_LIVE_WRITTEN;
+
+ for (i = BPF_REG_SIZE; i > BPF_REG_SIZE - size; i--)
+ state->stack[spi].slot_type[i - 1] = STACK_SPILL;
+
+ /* size < 8 bytes spill */
+ for (; i; i--)
+ scrub_spilled_slot(&state->stack[spi].slot_type[i - 1]);
+}
+
+static bool is_bpf_st_mem(struct bpf_insn *insn)
+{
+ return BPF_CLASS(insn->code) == BPF_ST && BPF_MODE(insn->code) == BPF_MEM;
+}
+
+/* check_stack_{read,write}_fixed_off functions track spill/fill of registers,
+ * stack boundary and alignment are checked in check_mem_access()
+ */
+static int check_stack_write_fixed_off(struct bpf_verifier_env *env,
+ /* stack frame we're writing to */
+ struct bpf_func_state *state,
+ int off, int size, int value_regno,
+ int insn_idx)
+{
+ struct bpf_func_state *cur; /* state of the current function */
+ int i, slot = -off - 1, spi = slot / BPF_REG_SIZE, err;
+ struct bpf_insn *insn = &env->prog->insnsi[insn_idx];
+ struct bpf_reg_state *reg = NULL;
+ u32 dst_reg = insn->dst_reg;
+
+ /* caller checked that off % size == 0 and -MAX_BPF_STACK <= off < 0,
+ * so it's aligned access and [off, off + size) are within stack limits
+ */
+ if (!env->allow_ptr_leaks &&
+ is_spilled_reg(&state->stack[spi]) &&
+ size != BPF_REG_SIZE) {
+ verbose(env, "attempt to corrupt spilled pointer on stack\n");
+ return -EACCES;
+ }
+
+ cur = env->cur_state->frame[env->cur_state->curframe];
+ if (value_regno >= 0)
+ reg = &cur->regs[value_regno];
+ if (!env->bypass_spec_v4) {
+ bool sanitize = reg && is_spillable_regtype(reg->type);
+
+ for (i = 0; i < size; i++) {
+ u8 type = state->stack[spi].slot_type[i];
+
+ if (type != STACK_MISC && type != STACK_ZERO) {
+ sanitize = true;
+ break;
+ }
+ }
+
+ if (sanitize)
+ env->insn_aux_data[insn_idx].sanitize_stack_spill = true;
+ }
+
+ err = destroy_if_dynptr_stack_slot(env, state, spi);
+ if (err)
+ return err;
+
+ mark_stack_slot_scratched(env, spi);
+ if (reg && !(off % BPF_REG_SIZE) && register_is_bounded(reg) &&
+ !register_is_null(reg) && env->bpf_capable) {
+ if (dst_reg != BPF_REG_FP) {
+ /* The backtracking logic can only recognize explicit
+ * stack slot address like [fp - 8]. Other spill of
+ * scalar via different register has to be conservative.
+ * Backtrack from here and mark all registers as precise
+ * that contributed into 'reg' being a constant.
+ */
+ err = mark_chain_precision(env, value_regno);
+ if (err)
+ return err;
+ }
+ save_register_state(state, spi, reg, size);
+ /* Break the relation on a narrowing spill. */
+ if (fls64(reg->umax_value) > BITS_PER_BYTE * size)
+ state->stack[spi].spilled_ptr.id = 0;
+ } else if (!reg && !(off % BPF_REG_SIZE) && is_bpf_st_mem(insn) &&
+ insn->imm != 0 && env->bpf_capable) {
+ struct bpf_reg_state fake_reg = {};
+
+ __mark_reg_known(&fake_reg, insn->imm);
+ fake_reg.type = SCALAR_VALUE;
+ save_register_state(state, spi, &fake_reg, size);
+ } else if (reg && is_spillable_regtype(reg->type)) {
+ /* register containing pointer is being spilled into stack */
+ if (size != BPF_REG_SIZE) {
+ verbose_linfo(env, insn_idx, "; ");
+ verbose(env, "invalid size of register spill\n");
+ return -EACCES;
+ }
+ if (state != cur && reg->type == PTR_TO_STACK) {
+ verbose(env, "cannot spill pointers to stack into stack frame of the caller\n");
+ return -EINVAL;
+ }
+ save_register_state(state, spi, reg, size);
+ } else {
+ u8 type = STACK_MISC;
+
+ /* regular write of data into stack destroys any spilled ptr */
+ state->stack[spi].spilled_ptr.type = NOT_INIT;
+ /* Mark slots as STACK_MISC if they belonged to spilled ptr/dynptr/iter. */
+ if (is_stack_slot_special(&state->stack[spi]))
+ for (i = 0; i < BPF_REG_SIZE; i++)
+ scrub_spilled_slot(&state->stack[spi].slot_type[i]);
+
+ /* only mark the slot as written if all 8 bytes were written
+ * otherwise read propagation may incorrectly stop too soon
+ * when stack slots are partially written.
+ * This heuristic means that read propagation will be
+ * conservative, since it will add reg_live_read marks
+ * to stack slots all the way to first state when programs
+ * writes+reads less than 8 bytes
+ */
+ if (size == BPF_REG_SIZE)
+ state->stack[spi].spilled_ptr.live |= REG_LIVE_WRITTEN;
+
+ /* when we zero initialize stack slots mark them as such */
+ if ((reg && register_is_null(reg)) ||
+ (!reg && is_bpf_st_mem(insn) && insn->imm == 0)) {
+ /* backtracking doesn't work for STACK_ZERO yet. */
+ err = mark_chain_precision(env, value_regno);
+ if (err)
+ return err;
+ type = STACK_ZERO;
+ }
+
+ /* Mark slots affected by this stack write. */
+ for (i = 0; i < size; i++)
+ state->stack[spi].slot_type[(slot - i) % BPF_REG_SIZE] =
+ type;
+ }
+ return 0;
+}
+
+/* Write the stack: 'stack[ptr_regno + off] = value_regno'. 'ptr_regno' is
+ * known to contain a variable offset.
+ * This function checks whether the write is permitted and conservatively
+ * tracks the effects of the write, considering that each stack slot in the
+ * dynamic range is potentially written to.
+ *
+ * 'off' includes 'regno->off'.
+ * 'value_regno' can be -1, meaning that an unknown value is being written to
+ * the stack.
+ *
+ * Spilled pointers in range are not marked as written because we don't know
+ * what's going to be actually written. This means that read propagation for
+ * future reads cannot be terminated by this write.
+ *
+ * For privileged programs, uninitialized stack slots are considered
+ * initialized by this write (even though we don't know exactly what offsets
+ * are going to be written to). The idea is that we don't want the verifier to
+ * reject future reads that access slots written to through variable offsets.
+ */
+static int check_stack_write_var_off(struct bpf_verifier_env *env,
+ /* func where register points to */
+ struct bpf_func_state *state,
+ int ptr_regno, int off, int size,
+ int value_regno, int insn_idx)
+{
+ struct bpf_func_state *cur; /* state of the current function */
+ int min_off, max_off;
+ int i, err;
+ struct bpf_reg_state *ptr_reg = NULL, *value_reg = NULL;
+ struct bpf_insn *insn = &env->prog->insnsi[insn_idx];
+ bool writing_zero = false;
+ /* set if the fact that we're writing a zero is used to let any
+ * stack slots remain STACK_ZERO
+ */
+ bool zero_used = false;
+
+ cur = env->cur_state->frame[env->cur_state->curframe];
+ ptr_reg = &cur->regs[ptr_regno];
+ min_off = ptr_reg->smin_value + off;
+ max_off = ptr_reg->smax_value + off + size;
+ if (value_regno >= 0)
+ value_reg = &cur->regs[value_regno];
+ if ((value_reg && register_is_null(value_reg)) ||
+ (!value_reg && is_bpf_st_mem(insn) && insn->imm == 0))
+ writing_zero = true;
+
+ for (i = min_off; i < max_off; i++) {
+ int spi;
+
+ spi = __get_spi(i);
+ err = destroy_if_dynptr_stack_slot(env, state, spi);
+ if (err)
+ return err;
+ }
+
+ /* Variable offset writes destroy any spilled pointers in range. */
+ for (i = min_off; i < max_off; i++) {
+ u8 new_type, *stype;
+ int slot, spi;
+
+ slot = -i - 1;
+ spi = slot / BPF_REG_SIZE;
+ stype = &state->stack[spi].slot_type[slot % BPF_REG_SIZE];
+ mark_stack_slot_scratched(env, spi);
+
+ if (!env->allow_ptr_leaks && *stype != STACK_MISC && *stype != STACK_ZERO) {
+ /* Reject the write if range we may write to has not
+ * been initialized beforehand. If we didn't reject
+ * here, the ptr status would be erased below (even
+ * though not all slots are actually overwritten),
+ * possibly opening the door to leaks.
+ *
+ * We do however catch STACK_INVALID case below, and
+ * only allow reading possibly uninitialized memory
+ * later for CAP_PERFMON, as the write may not happen to
+ * that slot.
+ */
+ verbose(env, "spilled ptr in range of var-offset stack write; insn %d, ptr off: %d",
+ insn_idx, i);
+ return -EINVAL;
+ }
+
+ /* Erase all spilled pointers. */
+ state->stack[spi].spilled_ptr.type = NOT_INIT;
+
+ /* Update the slot type. */
+ new_type = STACK_MISC;
+ if (writing_zero && *stype == STACK_ZERO) {
+ new_type = STACK_ZERO;
+ zero_used = true;
+ }
+ /* If the slot is STACK_INVALID, we check whether it's OK to
+ * pretend that it will be initialized by this write. The slot
+ * might not actually be written to, and so if we mark it as
+ * initialized future reads might leak uninitialized memory.
+ * For privileged programs, we will accept such reads to slots
+ * that may or may not be written because, if we're reject
+ * them, the error would be too confusing.
+ */
+ if (*stype == STACK_INVALID && !env->allow_uninit_stack) {
+ verbose(env, "uninit stack in range of var-offset write prohibited for !root; insn %d, off: %d",
+ insn_idx, i);
+ return -EINVAL;
+ }
+ *stype = new_type;
+ }
+ if (zero_used) {
+ /* backtracking doesn't work for STACK_ZERO yet. */
+ err = mark_chain_precision(env, value_regno);
+ if (err)
+ return err;
+ }
+ return 0;
+}
+
+/* When register 'dst_regno' is assigned some values from stack[min_off,
+ * max_off), we set the register's type according to the types of the
+ * respective stack slots. If all the stack values are known to be zeros, then
+ * so is the destination reg. Otherwise, the register is considered to be
+ * SCALAR. This function does not deal with register filling; the caller must
+ * ensure that all spilled registers in the stack range have been marked as
+ * read.
+ */
+static void mark_reg_stack_read(struct bpf_verifier_env *env,
+ /* func where src register points to */
+ struct bpf_func_state *ptr_state,
+ int min_off, int max_off, int dst_regno)
+{
+ struct bpf_verifier_state *vstate = env->cur_state;
+ struct bpf_func_state *state = vstate->frame[vstate->curframe];
+ int i, slot, spi;
+ u8 *stype;
+ int zeros = 0;
+
+ for (i = min_off; i < max_off; i++) {
+ slot = -i - 1;
+ spi = slot / BPF_REG_SIZE;
+ mark_stack_slot_scratched(env, spi);
+ stype = ptr_state->stack[spi].slot_type;
+ if (stype[slot % BPF_REG_SIZE] != STACK_ZERO)
+ break;
+ zeros++;
+ }
+ if (zeros == max_off - min_off) {
+ /* any access_size read into register is zero extended,
+ * so the whole register == const_zero
+ */
+ __mark_reg_const_zero(&state->regs[dst_regno]);
+ /* backtracking doesn't support STACK_ZERO yet,
+ * so mark it precise here, so that later
+ * backtracking can stop here.
+ * Backtracking may not need this if this register
+ * doesn't participate in pointer adjustment.
+ * Forward propagation of precise flag is not
+ * necessary either. This mark is only to stop
+ * backtracking. Any register that contributed
+ * to const 0 was marked precise before spill.
+ */
+ state->regs[dst_regno].precise = true;
+ } else {
+ /* have read misc data from the stack */
+ mark_reg_unknown(env, state->regs, dst_regno);
+ }
+ state->regs[dst_regno].live |= REG_LIVE_WRITTEN;
+}
+
+/* Read the stack at 'off' and put the results into the register indicated by
+ * 'dst_regno'. It handles reg filling if the addressed stack slot is a
+ * spilled reg.
+ *
+ * 'dst_regno' can be -1, meaning that the read value is not going to a
+ * register.
+ *
+ * The access is assumed to be within the current stack bounds.
+ */
+static int check_stack_read_fixed_off(struct bpf_verifier_env *env,
+ /* func where src register points to */
+ struct bpf_func_state *reg_state,
+ int off, int size, int dst_regno)
+{
+ struct bpf_verifier_state *vstate = env->cur_state;
+ struct bpf_func_state *state = vstate->frame[vstate->curframe];
+ int i, slot = -off - 1, spi = slot / BPF_REG_SIZE;
+ struct bpf_reg_state *reg;
+ u8 *stype, type;
+
+ stype = reg_state->stack[spi].slot_type;
+ reg = &reg_state->stack[spi].spilled_ptr;
+
+ mark_stack_slot_scratched(env, spi);
+
+ if (is_spilled_reg(&reg_state->stack[spi])) {
+ u8 spill_size = 1;
+
+ for (i = BPF_REG_SIZE - 1; i > 0 && stype[i - 1] == STACK_SPILL; i--)
+ spill_size++;
+
+ if (size != BPF_REG_SIZE || spill_size != BPF_REG_SIZE) {
+ if (reg->type != SCALAR_VALUE) {
+ verbose_linfo(env, env->insn_idx, "; ");
+ verbose(env, "invalid size of register fill\n");
+ return -EACCES;
+ }
+
+ mark_reg_read(env, reg, reg->parent, REG_LIVE_READ64);
+ if (dst_regno < 0)
+ return 0;
+
+ if (!(off % BPF_REG_SIZE) && size == spill_size) {
+ /* The earlier check_reg_arg() has decided the
+ * subreg_def for this insn. Save it first.
+ */
+ s32 subreg_def = state->regs[dst_regno].subreg_def;
+
+ copy_register_state(&state->regs[dst_regno], reg);
+ state->regs[dst_regno].subreg_def = subreg_def;
+ } else {
+ for (i = 0; i < size; i++) {
+ type = stype[(slot - i) % BPF_REG_SIZE];
+ if (type == STACK_SPILL)
+ continue;
+ if (type == STACK_MISC)
+ continue;
+ if (type == STACK_INVALID && env->allow_uninit_stack)
+ continue;
+ verbose(env, "invalid read from stack off %d+%d size %d\n",
+ off, i, size);
+ return -EACCES;
+ }
+ mark_reg_unknown(env, state->regs, dst_regno);
+ }
+ state->regs[dst_regno].live |= REG_LIVE_WRITTEN;
+ return 0;
+ }
+
+ if (dst_regno >= 0) {
+ /* restore register state from stack */
+ copy_register_state(&state->regs[dst_regno], reg);
+ /* mark reg as written since spilled pointer state likely
+ * has its liveness marks cleared by is_state_visited()
+ * which resets stack/reg liveness for state transitions
+ */
+ state->regs[dst_regno].live |= REG_LIVE_WRITTEN;
+ } else if (__is_pointer_value(env->allow_ptr_leaks, reg)) {
+ /* If dst_regno==-1, the caller is asking us whether
+ * it is acceptable to use this value as a SCALAR_VALUE
+ * (e.g. for XADD).
+ * We must not allow unprivileged callers to do that
+ * with spilled pointers.
+ */
+ verbose(env, "leaking pointer from stack off %d\n",
+ off);
+ return -EACCES;
+ }
+ mark_reg_read(env, reg, reg->parent, REG_LIVE_READ64);
+ } else {
+ for (i = 0; i < size; i++) {
+ type = stype[(slot - i) % BPF_REG_SIZE];
+ if (type == STACK_MISC)
+ continue;
+ if (type == STACK_ZERO)
+ continue;
+ if (type == STACK_INVALID && env->allow_uninit_stack)
+ continue;
+ verbose(env, "invalid read from stack off %d+%d size %d\n",
+ off, i, size);
+ return -EACCES;
+ }
+ mark_reg_read(env, reg, reg->parent, REG_LIVE_READ64);
+ if (dst_regno >= 0)
+ mark_reg_stack_read(env, reg_state, off, off + size, dst_regno);
+ }
+ return 0;
+}
+
+enum bpf_access_src {
+ ACCESS_DIRECT = 1, /* the access is performed by an instruction */
+ ACCESS_HELPER = 2, /* the access is performed by a helper */
+};
+
+static int check_stack_range_initialized(struct bpf_verifier_env *env,
+ int regno, int off, int access_size,
+ bool zero_size_allowed,
+ enum bpf_access_src type,
+ struct bpf_call_arg_meta *meta);
+
+static struct bpf_reg_state *reg_state(struct bpf_verifier_env *env, int regno)
+{
+ return cur_regs(env) + regno;
+}
+
+/* Read the stack at 'ptr_regno + off' and put the result into the register
+ * 'dst_regno'.
+ * 'off' includes the pointer register's fixed offset(i.e. 'ptr_regno.off'),
+ * but not its variable offset.
+ * 'size' is assumed to be <= reg size and the access is assumed to be aligned.
+ *
+ * As opposed to check_stack_read_fixed_off, this function doesn't deal with
+ * filling registers (i.e. reads of spilled register cannot be detected when
+ * the offset is not fixed). We conservatively mark 'dst_regno' as containing
+ * SCALAR_VALUE. That's why we assert that the 'ptr_regno' has a variable
+ * offset; for a fixed offset check_stack_read_fixed_off should be used
+ * instead.
+ */
+static int check_stack_read_var_off(struct bpf_verifier_env *env,
+ int ptr_regno, int off, int size, int dst_regno)
+{
+ /* The state of the source register. */
+ struct bpf_reg_state *reg = reg_state(env, ptr_regno);
+ struct bpf_func_state *ptr_state = func(env, reg);
+ int err;
+ int min_off, max_off;
+
+ /* Note that we pass a NULL meta, so raw access will not be permitted.
+ */
+ err = check_stack_range_initialized(env, ptr_regno, off, size,
+ false, ACCESS_DIRECT, NULL);
+ if (err)
+ return err;
+
+ min_off = reg->smin_value + off;
+ max_off = reg->smax_value + off;
+ mark_reg_stack_read(env, ptr_state, min_off, max_off + size, dst_regno);
+ return 0;
+}
+
+/* check_stack_read dispatches to check_stack_read_fixed_off or
+ * check_stack_read_var_off.
+ *
+ * The caller must ensure that the offset falls within the allocated stack
+ * bounds.
+ *
+ * 'dst_regno' is a register which will receive the value from the stack. It
+ * can be -1, meaning that the read value is not going to a register.
+ */
+static int check_stack_read(struct bpf_verifier_env *env,
+ int ptr_regno, int off, int size,
+ int dst_regno)
+{
+ struct bpf_reg_state *reg = reg_state(env, ptr_regno);
+ struct bpf_func_state *state = func(env, reg);
+ int err;
+ /* Some accesses are only permitted with a static offset. */
+ bool var_off = !tnum_is_const(reg->var_off);
+
+ /* The offset is required to be static when reads don't go to a
+ * register, in order to not leak pointers (see
+ * check_stack_read_fixed_off).
+ */
+ if (dst_regno < 0 && var_off) {
+ char tn_buf[48];
+
+ tnum_strn(tn_buf, sizeof(tn_buf), reg->var_off);
+ verbose(env, "variable offset stack pointer cannot be passed into helper function; var_off=%s off=%d size=%d\n",
+ tn_buf, off, size);
+ return -EACCES;
+ }
+ /* Variable offset is prohibited for unprivileged mode for simplicity
+ * since it requires corresponding support in Spectre masking for stack
+ * ALU. See also retrieve_ptr_limit(). The check in
+ * check_stack_access_for_ptr_arithmetic() called by
+ * adjust_ptr_min_max_vals() prevents users from creating stack pointers
+ * with variable offsets, therefore no check is required here. Further,
+ * just checking it here would be insufficient as speculative stack
+ * writes could still lead to unsafe speculative behaviour.
+ */
+ if (!var_off) {
+ off += reg->var_off.value;
+ err = check_stack_read_fixed_off(env, state, off, size,
+ dst_regno);
+ } else {
+ /* Variable offset stack reads need more conservative handling
+ * than fixed offset ones. Note that dst_regno >= 0 on this
+ * branch.
+ */
+ err = check_stack_read_var_off(env, ptr_regno, off, size,
+ dst_regno);
+ }
+ return err;
+}
+
+
+/* check_stack_write dispatches to check_stack_write_fixed_off or
+ * check_stack_write_var_off.
+ *
+ * 'ptr_regno' is the register used as a pointer into the stack.
+ * 'off' includes 'ptr_regno->off', but not its variable offset (if any).
+ * 'value_regno' is the register whose value we're writing to the stack. It can
+ * be -1, meaning that we're not writing from a register.
+ *
+ * The caller must ensure that the offset falls within the maximum stack size.
+ */
+static int check_stack_write(struct bpf_verifier_env *env,
+ int ptr_regno, int off, int size,
+ int value_regno, int insn_idx)
+{
+ struct bpf_reg_state *reg = reg_state(env, ptr_regno);
+ struct bpf_func_state *state = func(env, reg);
+ int err;
+
+ if (tnum_is_const(reg->var_off)) {
+ off += reg->var_off.value;
+ err = check_stack_write_fixed_off(env, state, off, size,
+ value_regno, insn_idx);
+ } else {
+ /* Variable offset stack reads need more conservative handling
+ * than fixed offset ones.
+ */
+ err = check_stack_write_var_off(env, state,
+ ptr_regno, off, size,
+ value_regno, insn_idx);
+ }
+ return err;
+}
+
+static int check_map_access_type(struct bpf_verifier_env *env, u32 regno,
+ int off, int size, enum bpf_access_type type)
+{
+ struct bpf_reg_state *regs = cur_regs(env);
+ struct bpf_map *map = regs[regno].map_ptr;
+ u32 cap = bpf_map_flags_to_cap(map);
+
+ if (type == BPF_WRITE && !(cap & BPF_MAP_CAN_WRITE)) {
+ verbose(env, "write into map forbidden, value_size=%d off=%d size=%d\n",
+ map->value_size, off, size);
+ return -EACCES;
+ }
+
+ if (type == BPF_READ && !(cap & BPF_MAP_CAN_READ)) {
+ verbose(env, "read from map forbidden, value_size=%d off=%d size=%d\n",
+ map->value_size, off, size);
+ return -EACCES;
+ }
+
+ return 0;
+}
+
+/* check read/write into memory region (e.g., map value, ringbuf sample, etc) */
+static int __check_mem_access(struct bpf_verifier_env *env, int regno,
+ int off, int size, u32 mem_size,
+ bool zero_size_allowed)
+{
+ bool size_ok = size > 0 || (size == 0 && zero_size_allowed);
+ struct bpf_reg_state *reg;
+
+ if (off >= 0 && size_ok && (u64)off + size <= mem_size)
+ return 0;
+
+ reg = &cur_regs(env)[regno];
+ switch (reg->type) {
+ case PTR_TO_MAP_KEY:
+ verbose(env, "invalid access to map key, key_size=%d off=%d size=%d\n",
+ mem_size, off, size);
+ break;
+ case PTR_TO_MAP_VALUE:
+ verbose(env, "invalid access to map value, value_size=%d off=%d size=%d\n",
+ mem_size, off, size);
+ break;
+ case PTR_TO_PACKET:
+ case PTR_TO_PACKET_META:
+ case PTR_TO_PACKET_END:
+ verbose(env, "invalid access to packet, off=%d size=%d, R%d(id=%d,off=%d,r=%d)\n",
+ off, size, regno, reg->id, off, mem_size);
+ break;
+ case PTR_TO_MEM:
+ default:
+ verbose(env, "invalid access to memory, mem_size=%u off=%d size=%d\n",
+ mem_size, off, size);
+ }
+
+ return -EACCES;
+}
+
+/* check read/write into a memory region with possible variable offset */
+static int check_mem_region_access(struct bpf_verifier_env *env, u32 regno,
+ int off, int size, u32 mem_size,
+ bool zero_size_allowed)
+{
+ struct bpf_verifier_state *vstate = env->cur_state;
+ struct bpf_func_state *state = vstate->frame[vstate->curframe];
+ struct bpf_reg_state *reg = &state->regs[regno];
+ int err;
+
+ /* We may have adjusted the register pointing to memory region, so we
+ * need to try adding each of min_value and max_value to off
+ * to make sure our theoretical access will be safe.
+ *
+ * The minimum value is only important with signed
+ * comparisons where we can't assume the floor of a
+ * value is 0. If we are using signed variables for our
+ * index'es we need to make sure that whatever we use
+ * will have a set floor within our range.
+ */
+ if (reg->smin_value < 0 &&
+ (reg->smin_value == S64_MIN ||
+ (off + reg->smin_value != (s64)(s32)(off + reg->smin_value)) ||
+ reg->smin_value + off < 0)) {
+ verbose(env, "R%d min value is negative, either use unsigned index or do a if (index >=0) check.\n",
+ regno);
+ return -EACCES;
+ }
+ err = __check_mem_access(env, regno, reg->smin_value + off, size,
+ mem_size, zero_size_allowed);
+ if (err) {
+ verbose(env, "R%d min value is outside of the allowed memory range\n",
+ regno);
+ return err;
+ }
+
+ /* If we haven't set a max value then we need to bail since we can't be
+ * sure we won't do bad things.
+ * If reg->umax_value + off could overflow, treat that as unbounded too.
+ */
+ if (reg->umax_value >= BPF_MAX_VAR_OFF) {
+ verbose(env, "R%d unbounded memory access, make sure to bounds check any such access\n",
+ regno);
+ return -EACCES;
+ }
+ err = __check_mem_access(env, regno, reg->umax_value + off, size,
+ mem_size, zero_size_allowed);
+ if (err) {
+ verbose(env, "R%d max value is outside of the allowed memory range\n",
+ regno);
+ return err;
+ }
+
+ return 0;
+}
+
+static int __check_ptr_off_reg(struct bpf_verifier_env *env,
+ const struct bpf_reg_state *reg, int regno,
+ bool fixed_off_ok)
+{
+ /* Access to this pointer-typed register or passing it to a helper
+ * is only allowed in its original, unmodified form.
+ */
+
+ if (reg->off < 0) {
+ verbose(env, "negative offset %s ptr R%d off=%d disallowed\n",
+ reg_type_str(env, reg->type), regno, reg->off);
+ return -EACCES;
+ }
+
+ if (!fixed_off_ok && reg->off) {
+ verbose(env, "dereference of modified %s ptr R%d off=%d disallowed\n",
+ reg_type_str(env, reg->type), regno, reg->off);
+ return -EACCES;
+ }
+
+ if (!tnum_is_const(reg->var_off) || reg->var_off.value) {
+ char tn_buf[48];
+
+ tnum_strn(tn_buf, sizeof(tn_buf), reg->var_off);
+ verbose(env, "variable %s access var_off=%s disallowed\n",
+ reg_type_str(env, reg->type), tn_buf);
+ return -EACCES;
+ }
+
+ return 0;
+}
+
+int check_ptr_off_reg(struct bpf_verifier_env *env,
+ const struct bpf_reg_state *reg, int regno)
+{
+ return __check_ptr_off_reg(env, reg, regno, false);
+}
+
+static int map_kptr_match_type(struct bpf_verifier_env *env,
+ struct btf_field *kptr_field,
+ struct bpf_reg_state *reg, u32 regno)
+{
+ const char *targ_name = btf_type_name(kptr_field->kptr.btf, kptr_field->kptr.btf_id);
+ int perm_flags;
+ const char *reg_name = "";
+
+ if (btf_is_kernel(reg->btf)) {
+ perm_flags = PTR_MAYBE_NULL | PTR_TRUSTED | MEM_RCU;
+
+ /* Only unreferenced case accepts untrusted pointers */
+ if (kptr_field->type == BPF_KPTR_UNREF)
+ perm_flags |= PTR_UNTRUSTED;
+ } else {
+ perm_flags = PTR_MAYBE_NULL | MEM_ALLOC;
+ }
+
+ if (base_type(reg->type) != PTR_TO_BTF_ID || (type_flag(reg->type) & ~perm_flags))
+ goto bad_type;
+
+ /* We need to verify reg->type and reg->btf, before accessing reg->btf */
+ reg_name = btf_type_name(reg->btf, reg->btf_id);
+
+ /* For ref_ptr case, release function check should ensure we get one
+ * referenced PTR_TO_BTF_ID, and that its fixed offset is 0. For the
+ * normal store of unreferenced kptr, we must ensure var_off is zero.
+ * Since ref_ptr cannot be accessed directly by BPF insns, checks for
+ * reg->off and reg->ref_obj_id are not needed here.
+ */
+ if (__check_ptr_off_reg(env, reg, regno, true))
+ return -EACCES;
+
+ /* A full type match is needed, as BTF can be vmlinux, module or prog BTF, and
+ * we also need to take into account the reg->off.
+ *
+ * We want to support cases like:
+ *
+ * struct foo {
+ * struct bar br;
+ * struct baz bz;
+ * };
+ *
+ * struct foo *v;
+ * v = func(); // PTR_TO_BTF_ID
+ * val->foo = v; // reg->off is zero, btf and btf_id match type
+ * val->bar = &v->br; // reg->off is still zero, but we need to retry with
+ * // first member type of struct after comparison fails
+ * val->baz = &v->bz; // reg->off is non-zero, so struct needs to be walked
+ * // to match type
+ *
+ * In the kptr_ref case, check_func_arg_reg_off already ensures reg->off
+ * is zero. We must also ensure that btf_struct_ids_match does not walk
+ * the struct to match type against first member of struct, i.e. reject
+ * second case from above. Hence, when type is BPF_KPTR_REF, we set
+ * strict mode to true for type match.
+ */
+ if (!btf_struct_ids_match(&env->log, reg->btf, reg->btf_id, reg->off,
+ kptr_field->kptr.btf, kptr_field->kptr.btf_id,
+ kptr_field->type == BPF_KPTR_REF))
+ goto bad_type;
+ return 0;
+bad_type:
+ verbose(env, "invalid kptr access, R%d type=%s%s ", regno,
+ reg_type_str(env, reg->type), reg_name);
+ verbose(env, "expected=%s%s", reg_type_str(env, PTR_TO_BTF_ID), targ_name);
+ if (kptr_field->type == BPF_KPTR_UNREF)
+ verbose(env, " or %s%s\n", reg_type_str(env, PTR_TO_BTF_ID | PTR_UNTRUSTED),
+ targ_name);
+ else
+ verbose(env, "\n");
+ return -EINVAL;
+}
+
+/* The non-sleepable programs and sleepable programs with explicit bpf_rcu_read_lock()
+ * can dereference RCU protected pointers and result is PTR_TRUSTED.
+ */
+static bool in_rcu_cs(struct bpf_verifier_env *env)
+{
+ return env->cur_state->active_rcu_lock ||
+ env->cur_state->active_lock.ptr ||
+ !env->prog->aux->sleepable;
+}
+
+/* Once GCC supports btf_type_tag the following mechanism will be replaced with tag check */
+BTF_SET_START(rcu_protected_types)
+BTF_ID(struct, prog_test_ref_kfunc)
+BTF_ID(struct, cgroup)
+BTF_ID(struct, bpf_cpumask)
+BTF_ID(struct, task_struct)
+BTF_SET_END(rcu_protected_types)
+
+static bool rcu_protected_object(const struct btf *btf, u32 btf_id)
+{
+ if (!btf_is_kernel(btf))
+ return false;
+ return btf_id_set_contains(&rcu_protected_types, btf_id);
+}
+
+static bool rcu_safe_kptr(const struct btf_field *field)
+{
+ const struct btf_field_kptr *kptr = &field->kptr;
+
+ return field->type == BPF_KPTR_REF && rcu_protected_object(kptr->btf, kptr->btf_id);
+}
+
+static int check_map_kptr_access(struct bpf_verifier_env *env, u32 regno,
+ int value_regno, int insn_idx,
+ struct btf_field *kptr_field)
+{
+ struct bpf_insn *insn = &env->prog->insnsi[insn_idx];
+ int class = BPF_CLASS(insn->code);
+ struct bpf_reg_state *val_reg;
+
+ /* Things we already checked for in check_map_access and caller:
+ * - Reject cases where variable offset may touch kptr
+ * - size of access (must be BPF_DW)
+ * - tnum_is_const(reg->var_off)
+ * - kptr_field->offset == off + reg->var_off.value
+ */
+ /* Only BPF_[LDX,STX,ST] | BPF_MEM | BPF_DW is supported */
+ if (BPF_MODE(insn->code) != BPF_MEM) {
+ verbose(env, "kptr in map can only be accessed using BPF_MEM instruction mode\n");
+ return -EACCES;
+ }
+
+ /* We only allow loading referenced kptr, since it will be marked as
+ * untrusted, similar to unreferenced kptr.
+ */
+ if (class != BPF_LDX && kptr_field->type == BPF_KPTR_REF) {
+ verbose(env, "store to referenced kptr disallowed\n");
+ return -EACCES;
+ }
+
+ if (class == BPF_LDX) {
+ val_reg = reg_state(env, value_regno);
+ /* We can simply mark the value_regno receiving the pointer
+ * value from map as PTR_TO_BTF_ID, with the correct type.
+ */
+ mark_btf_ld_reg(env, cur_regs(env), value_regno, PTR_TO_BTF_ID, kptr_field->kptr.btf,
+ kptr_field->kptr.btf_id,
+ rcu_safe_kptr(kptr_field) && in_rcu_cs(env) ?
+ PTR_MAYBE_NULL | MEM_RCU :
+ PTR_MAYBE_NULL | PTR_UNTRUSTED);
+ /* For mark_ptr_or_null_reg */
+ val_reg->id = ++env->id_gen;
+ } else if (class == BPF_STX) {
+ val_reg = reg_state(env, value_regno);
+ if (!register_is_null(val_reg) &&
+ map_kptr_match_type(env, kptr_field, val_reg, value_regno))
+ return -EACCES;
+ } else if (class == BPF_ST) {
+ if (insn->imm) {
+ verbose(env, "BPF_ST imm must be 0 when storing to kptr at off=%u\n",
+ kptr_field->offset);
+ return -EACCES;
+ }
+ } else {
+ verbose(env, "kptr in map can only be accessed using BPF_LDX/BPF_STX/BPF_ST\n");
+ return -EACCES;
+ }
+ return 0;
+}
+
+/* check read/write into a map element with possible variable offset */
+static int check_map_access(struct bpf_verifier_env *env, u32 regno,
+ int off, int size, bool zero_size_allowed,
+ enum bpf_access_src src)
+{
+ struct bpf_verifier_state *vstate = env->cur_state;
+ struct bpf_func_state *state = vstate->frame[vstate->curframe];
+ struct bpf_reg_state *reg = &state->regs[regno];
+ struct bpf_map *map = reg->map_ptr;
+ struct btf_record *rec;
+ int err, i;
+
+ err = check_mem_region_access(env, regno, off, size, map->value_size,
+ zero_size_allowed);
+ if (err)
+ return err;
+
+ if (IS_ERR_OR_NULL(map->record))
+ return 0;
+ rec = map->record;
+ for (i = 0; i < rec->cnt; i++) {
+ struct btf_field *field = &rec->fields[i];
+ u32 p = field->offset;
+
+ /* If any part of a field can be touched by load/store, reject
+ * this program. To check that [x1, x2) overlaps with [y1, y2),
+ * it is sufficient to check x1 < y2 && y1 < x2.
+ */
+ if (reg->smin_value + off < p + btf_field_type_size(field->type) &&
+ p < reg->umax_value + off + size) {
+ switch (field->type) {
+ case BPF_KPTR_UNREF:
+ case BPF_KPTR_REF:
+ if (src != ACCESS_DIRECT) {
+ verbose(env, "kptr cannot be accessed indirectly by helper\n");
+ return -EACCES;
+ }
+ if (!tnum_is_const(reg->var_off)) {
+ verbose(env, "kptr access cannot have variable offset\n");
+ return -EACCES;
+ }
+ if (p != off + reg->var_off.value) {
+ verbose(env, "kptr access misaligned expected=%u off=%llu\n",
+ p, off + reg->var_off.value);
+ return -EACCES;
+ }
+ if (size != bpf_size_to_bytes(BPF_DW)) {
+ verbose(env, "kptr access size must be BPF_DW\n");
+ return -EACCES;
+ }
+ break;
+ default:
+ verbose(env, "%s cannot be accessed directly by load/store\n",
+ btf_field_type_name(field->type));
+ return -EACCES;
+ }
+ }
+ }
+ return 0;
+}
+
+#define MAX_PACKET_OFF 0xffff
+
+static bool may_access_direct_pkt_data(struct bpf_verifier_env *env,
+ const struct bpf_call_arg_meta *meta,
+ enum bpf_access_type t)
+{
+ enum bpf_prog_type prog_type = resolve_prog_type(env->prog);
+
+ switch (prog_type) {
+ /* Program types only with direct read access go here! */
+ case BPF_PROG_TYPE_LWT_IN:
+ case BPF_PROG_TYPE_LWT_OUT:
+ case BPF_PROG_TYPE_LWT_SEG6LOCAL:
+ case BPF_PROG_TYPE_SK_REUSEPORT:
+ case BPF_PROG_TYPE_FLOW_DISSECTOR:
+ case BPF_PROG_TYPE_CGROUP_SKB:
+ if (t == BPF_WRITE)
+ return false;
+ fallthrough;
+
+ /* Program types with direct read + write access go here! */
+ case BPF_PROG_TYPE_SCHED_CLS:
+ case BPF_PROG_TYPE_SCHED_ACT:
+ case BPF_PROG_TYPE_XDP:
+ case BPF_PROG_TYPE_LWT_XMIT:
+ case BPF_PROG_TYPE_SK_SKB:
+ case BPF_PROG_TYPE_SK_MSG:
+ if (meta)
+ return meta->pkt_access;
+
+ env->seen_direct_write = true;
+ return true;
+
+ case BPF_PROG_TYPE_CGROUP_SOCKOPT:
+ if (t == BPF_WRITE)
+ env->seen_direct_write = true;
+
+ return true;
+
+ default:
+ return false;
+ }
+}
+
+static int check_packet_access(struct bpf_verifier_env *env, u32 regno, int off,
+ int size, bool zero_size_allowed)
+{
+ struct bpf_reg_state *regs = cur_regs(env);
+ struct bpf_reg_state *reg = &regs[regno];
+ int err;
+
+ /* We may have added a variable offset to the packet pointer; but any
+ * reg->range we have comes after that. We are only checking the fixed
+ * offset.
+ */
+
+ /* We don't allow negative numbers, because we aren't tracking enough
+ * detail to prove they're safe.
+ */
+ if (reg->smin_value < 0) {
+ verbose(env, "R%d min value is negative, either use unsigned index or do a if (index >=0) check.\n",
+ regno);
+ return -EACCES;
+ }
+
+ err = reg->range < 0 ? -EINVAL :
+ __check_mem_access(env, regno, off, size, reg->range,
+ zero_size_allowed);
+ if (err) {
+ verbose(env, "R%d offset is outside of the packet\n", regno);
+ return err;
+ }
+
+ /* __check_mem_access has made sure "off + size - 1" is within u16.
+ * reg->umax_value can't be bigger than MAX_PACKET_OFF which is 0xffff,
+ * otherwise find_good_pkt_pointers would have refused to set range info
+ * that __check_mem_access would have rejected this pkt access.
+ * Therefore, "off + reg->umax_value + size - 1" won't overflow u32.
+ */
+ env->prog->aux->max_pkt_offset =
+ max_t(u32, env->prog->aux->max_pkt_offset,
+ off + reg->umax_value + size - 1);
+
+ return err;
+}
+
+/* check access to 'struct bpf_context' fields. Supports fixed offsets only */
+static int check_ctx_access(struct bpf_verifier_env *env, int insn_idx, int off, int size,
+ enum bpf_access_type t, enum bpf_reg_type *reg_type,
+ struct btf **btf, u32 *btf_id)
+{
+ struct bpf_insn_access_aux info = {
+ .reg_type = *reg_type,
+ .log = &env->log,
+ };
+
+ if (env->ops->is_valid_access &&
+ env->ops->is_valid_access(off, size, t, env->prog, &info)) {
+ /* A non zero info.ctx_field_size indicates that this field is a
+ * candidate for later verifier transformation to load the whole
+ * field and then apply a mask when accessed with a narrower
+ * access than actual ctx access size. A zero info.ctx_field_size
+ * will only allow for whole field access and rejects any other
+ * type of narrower access.
+ */
+ *reg_type = info.reg_type;
+
+ if (base_type(*reg_type) == PTR_TO_BTF_ID) {
+ *btf = info.btf;
+ *btf_id = info.btf_id;
+ } else {
+ env->insn_aux_data[insn_idx].ctx_field_size = info.ctx_field_size;
+ }
+ /* remember the offset of last byte accessed in ctx */
+ if (env->prog->aux->max_ctx_offset < off + size)
+ env->prog->aux->max_ctx_offset = off + size;
+ return 0;
+ }
+
+ verbose(env, "invalid bpf_context access off=%d size=%d\n", off, size);
+ return -EACCES;
+}
+
+static int check_flow_keys_access(struct bpf_verifier_env *env, int off,
+ int size)
+{
+ if (size < 0 || off < 0 ||
+ (u64)off + size > sizeof(struct bpf_flow_keys)) {
+ verbose(env, "invalid access to flow keys off=%d size=%d\n",
+ off, size);
+ return -EACCES;
+ }
+ return 0;
+}
+
+static int check_sock_access(struct bpf_verifier_env *env, int insn_idx,
+ u32 regno, int off, int size,
+ enum bpf_access_type t)
+{
+ struct bpf_reg_state *regs = cur_regs(env);
+ struct bpf_reg_state *reg = &regs[regno];
+ struct bpf_insn_access_aux info = {};
+ bool valid;
+
+ if (reg->smin_value < 0) {
+ verbose(env, "R%d min value is negative, either use unsigned index or do a if (index >=0) check.\n",
+ regno);
+ return -EACCES;
+ }
+
+ switch (reg->type) {
+ case PTR_TO_SOCK_COMMON:
+ valid = bpf_sock_common_is_valid_access(off, size, t, &info);
+ break;
+ case PTR_TO_SOCKET:
+ valid = bpf_sock_is_valid_access(off, size, t, &info);
+ break;
+ case PTR_TO_TCP_SOCK:
+ valid = bpf_tcp_sock_is_valid_access(off, size, t, &info);
+ break;
+ case PTR_TO_XDP_SOCK:
+ valid = bpf_xdp_sock_is_valid_access(off, size, t, &info);
+ break;
+ default:
+ valid = false;
+ }
+
+
+ if (valid) {
+ env->insn_aux_data[insn_idx].ctx_field_size =
+ info.ctx_field_size;
+ return 0;
+ }
+
+ verbose(env, "R%d invalid %s access off=%d size=%d\n",
+ regno, reg_type_str(env, reg->type), off, size);
+
+ return -EACCES;
+}
+
+static bool is_pointer_value(struct bpf_verifier_env *env, int regno)
+{
+ return __is_pointer_value(env->allow_ptr_leaks, reg_state(env, regno));
+}
+
+static bool is_ctx_reg(struct bpf_verifier_env *env, int regno)
+{
+ const struct bpf_reg_state *reg = reg_state(env, regno);
+
+ return reg->type == PTR_TO_CTX;
+}
+
+static bool is_sk_reg(struct bpf_verifier_env *env, int regno)
+{
+ const struct bpf_reg_state *reg = reg_state(env, regno);
+
+ return type_is_sk_pointer(reg->type);
+}
+
+static bool is_pkt_reg(struct bpf_verifier_env *env, int regno)
+{
+ const struct bpf_reg_state *reg = reg_state(env, regno);
+
+ return type_is_pkt_pointer(reg->type);
+}
+
+static bool is_flow_key_reg(struct bpf_verifier_env *env, int regno)
+{
+ const struct bpf_reg_state *reg = reg_state(env, regno);
+
+ /* Separate to is_ctx_reg() since we still want to allow BPF_ST here. */
+ return reg->type == PTR_TO_FLOW_KEYS;
+}
+
+static u32 *reg2btf_ids[__BPF_REG_TYPE_MAX] = {
+#ifdef CONFIG_NET
+ [PTR_TO_SOCKET] = &btf_sock_ids[BTF_SOCK_TYPE_SOCK],
+ [PTR_TO_SOCK_COMMON] = &btf_sock_ids[BTF_SOCK_TYPE_SOCK_COMMON],
+ [PTR_TO_TCP_SOCK] = &btf_sock_ids[BTF_SOCK_TYPE_TCP],
+#endif
+ [CONST_PTR_TO_MAP] = btf_bpf_map_id,
+};
+
+static bool is_trusted_reg(const struct bpf_reg_state *reg)
+{
+ /* A referenced register is always trusted. */
+ if (reg->ref_obj_id)
+ return true;
+
+ /* Types listed in the reg2btf_ids are always trusted */
+ if (reg2btf_ids[base_type(reg->type)])
+ return true;
+
+ /* If a register is not referenced, it is trusted if it has the
+ * MEM_ALLOC or PTR_TRUSTED type modifiers, and no others. Some of the
+ * other type modifiers may be safe, but we elect to take an opt-in
+ * approach here as some (e.g. PTR_UNTRUSTED and PTR_MAYBE_NULL) are
+ * not.
+ *
+ * Eventually, we should make PTR_TRUSTED the single source of truth
+ * for whether a register is trusted.
+ */
+ return type_flag(reg->type) & BPF_REG_TRUSTED_MODIFIERS &&
+ !bpf_type_has_unsafe_modifiers(reg->type);
+}
+
+static bool is_rcu_reg(const struct bpf_reg_state *reg)
+{
+ return reg->type & MEM_RCU;
+}
+
+static void clear_trusted_flags(enum bpf_type_flag *flag)
+{
+ *flag &= ~(BPF_REG_TRUSTED_MODIFIERS | MEM_RCU);
+}
+
+static int check_pkt_ptr_alignment(struct bpf_verifier_env *env,
+ const struct bpf_reg_state *reg,
+ int off, int size, bool strict)
+{
+ struct tnum reg_off;
+ int ip_align;
+
+ /* Byte size accesses are always allowed. */
+ if (!strict || size == 1)
+ return 0;
+
+ /* For platforms that do not have a Kconfig enabling
+ * CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS the value of
+ * NET_IP_ALIGN is universally set to '2'. And on platforms
+ * that do set CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS, we get
+ * to this code only in strict mode where we want to emulate
+ * the NET_IP_ALIGN==2 checking. Therefore use an
+ * unconditional IP align value of '2'.
+ */
+ ip_align = 2;
+
+ reg_off = tnum_add(reg->var_off, tnum_const(ip_align + reg->off + off));
+ if (!tnum_is_aligned(reg_off, size)) {
+ char tn_buf[48];
+
+ tnum_strn(tn_buf, sizeof(tn_buf), reg->var_off);
+ verbose(env,
+ "misaligned packet access off %d+%s+%d+%d size %d\n",
+ ip_align, tn_buf, reg->off, off, size);
+ return -EACCES;
+ }
+
+ return 0;
+}
+
+static int check_generic_ptr_alignment(struct bpf_verifier_env *env,
+ const struct bpf_reg_state *reg,
+ const char *pointer_desc,
+ int off, int size, bool strict)
+{
+ struct tnum reg_off;
+
+ /* Byte size accesses are always allowed. */
+ if (!strict || size == 1)
+ return 0;
+
+ reg_off = tnum_add(reg->var_off, tnum_const(reg->off + off));
+ if (!tnum_is_aligned(reg_off, size)) {
+ char tn_buf[48];
+
+ tnum_strn(tn_buf, sizeof(tn_buf), reg->var_off);
+ verbose(env, "misaligned %saccess off %s+%d+%d size %d\n",
+ pointer_desc, tn_buf, reg->off, off, size);
+ return -EACCES;
+ }
+
+ return 0;
+}
+
+static int check_ptr_alignment(struct bpf_verifier_env *env,
+ const struct bpf_reg_state *reg, int off,
+ int size, bool strict_alignment_once)
+{
+ bool strict = env->strict_alignment || strict_alignment_once;
+ const char *pointer_desc = "";
+
+ switch (reg->type) {
+ case PTR_TO_PACKET:
+ case PTR_TO_PACKET_META:
+ /* Special case, because of NET_IP_ALIGN. Given metadata sits
+ * right in front, treat it the very same way.
+ */
+ return check_pkt_ptr_alignment(env, reg, off, size, strict);
+ case PTR_TO_FLOW_KEYS:
+ pointer_desc = "flow keys ";
+ break;
+ case PTR_TO_MAP_KEY:
+ pointer_desc = "key ";
+ break;
+ case PTR_TO_MAP_VALUE:
+ pointer_desc = "value ";
+ break;
+ case PTR_TO_CTX:
+ pointer_desc = "context ";
+ break;
+ case PTR_TO_STACK:
+ pointer_desc = "stack ";
+ /* The stack spill tracking logic in check_stack_write_fixed_off()
+ * and check_stack_read_fixed_off() relies on stack accesses being
+ * aligned.
+ */
+ strict = true;
+ break;
+ case PTR_TO_SOCKET:
+ pointer_desc = "sock ";
+ break;
+ case PTR_TO_SOCK_COMMON:
+ pointer_desc = "sock_common ";
+ break;
+ case PTR_TO_TCP_SOCK:
+ pointer_desc = "tcp_sock ";
+ break;
+ case PTR_TO_XDP_SOCK:
+ pointer_desc = "xdp_sock ";
+ break;
+ default:
+ break;
+ }
+ return check_generic_ptr_alignment(env, reg, pointer_desc, off, size,
+ strict);
+}
+
+/* starting from main bpf function walk all instructions of the function
+ * and recursively walk all callees that given function can call.
+ * Ignore jump and exit insns.
+ * Since recursion is prevented by check_cfg() this algorithm
+ * only needs a local stack of MAX_CALL_FRAMES to remember callsites
+ */
+static int check_max_stack_depth_subprog(struct bpf_verifier_env *env, int idx)
+{
+ struct bpf_subprog_info *subprog = env->subprog_info;
+ struct bpf_insn *insn = env->prog->insnsi;
+ int depth = 0, frame = 0, i, subprog_end;
+ bool tail_call_reachable = false;
+ int ret_insn[MAX_CALL_FRAMES];
+ int ret_prog[MAX_CALL_FRAMES];
+ int j;
+
+ i = subprog[idx].start;
+process_func:
+ /* protect against potential stack overflow that might happen when
+ * bpf2bpf calls get combined with tailcalls. Limit the caller's stack
+ * depth for such case down to 256 so that the worst case scenario
+ * would result in 8k stack size (32 which is tailcall limit * 256 =
+ * 8k).
+ *
+ * To get the idea what might happen, see an example:
+ * func1 -> sub rsp, 128
+ * subfunc1 -> sub rsp, 256
+ * tailcall1 -> add rsp, 256
+ * func2 -> sub rsp, 192 (total stack size = 128 + 192 = 320)
+ * subfunc2 -> sub rsp, 64
+ * subfunc22 -> sub rsp, 128
+ * tailcall2 -> add rsp, 128
+ * func3 -> sub rsp, 32 (total stack size 128 + 192 + 64 + 32 = 416)
+ *
+ * tailcall will unwind the current stack frame but it will not get rid
+ * of caller's stack as shown on the example above.
+ */
+ if (idx && subprog[idx].has_tail_call && depth >= 256) {
+ verbose(env,
+ "tail_calls are not allowed when call stack of previous frames is %d bytes. Too large\n",
+ depth);
+ return -EACCES;
+ }
+ /* round up to 32-bytes, since this is granularity
+ * of interpreter stack size
+ */
+ depth += round_up(max_t(u32, subprog[idx].stack_depth, 1), 32);
+ if (depth > MAX_BPF_STACK) {
+ verbose(env, "combined stack size of %d calls is %d. Too large\n",
+ frame + 1, depth);
+ return -EACCES;
+ }
+continue_func:
+ subprog_end = subprog[idx + 1].start;
+ for (; i < subprog_end; i++) {
+ int next_insn, sidx;
+
+ if (!bpf_pseudo_call(insn + i) && !bpf_pseudo_func(insn + i))
+ continue;
+ /* remember insn and function to return to */
+ ret_insn[frame] = i + 1;
+ ret_prog[frame] = idx;
+
+ /* find the callee */
+ next_insn = i + insn[i].imm + 1;
+ sidx = find_subprog(env, next_insn);
+ if (sidx < 0) {
+ WARN_ONCE(1, "verifier bug. No program starts at insn %d\n",
+ next_insn);
+ return -EFAULT;
+ }
+ if (subprog[sidx].is_async_cb) {
+ if (subprog[sidx].has_tail_call) {
+ verbose(env, "verifier bug. subprog has tail_call and async cb\n");
+ return -EFAULT;
+ }
+ /* async callbacks don't increase bpf prog stack size unless called directly */
+ if (!bpf_pseudo_call(insn + i))
+ continue;
+ }
+ i = next_insn;
+ idx = sidx;
+
+ if (subprog[idx].has_tail_call)
+ tail_call_reachable = true;
+
+ frame++;
+ if (frame >= MAX_CALL_FRAMES) {
+ verbose(env, "the call stack of %d frames is too deep !\n",
+ frame);
+ return -E2BIG;
+ }
+ goto process_func;
+ }
+ /* if tail call got detected across bpf2bpf calls then mark each of the
+ * currently present subprog frames as tail call reachable subprogs;
+ * this info will be utilized by JIT so that we will be preserving the
+ * tail call counter throughout bpf2bpf calls combined with tailcalls
+ */
+ if (tail_call_reachable)
+ for (j = 0; j < frame; j++)
+ subprog[ret_prog[j]].tail_call_reachable = true;
+ if (subprog[0].tail_call_reachable)
+ env->prog->aux->tail_call_reachable = true;
+
+ /* end of for() loop means the last insn of the 'subprog'
+ * was reached. Doesn't matter whether it was JA or EXIT
+ */
+ if (frame == 0)
+ return 0;
+ depth -= round_up(max_t(u32, subprog[idx].stack_depth, 1), 32);
+ frame--;
+ i = ret_insn[frame];
+ idx = ret_prog[frame];
+ goto continue_func;
+}
+
+static int check_max_stack_depth(struct bpf_verifier_env *env)
+{
+ struct bpf_subprog_info *si = env->subprog_info;
+ int ret;
+
+ for (int i = 0; i < env->subprog_cnt; i++) {
+ if (!i || si[i].is_async_cb) {
+ ret = check_max_stack_depth_subprog(env, i);
+ if (ret < 0)
+ return ret;
+ }
+ continue;
+ }
+ return 0;
+}
+
+#ifndef CONFIG_BPF_JIT_ALWAYS_ON
+static int get_callee_stack_depth(struct bpf_verifier_env *env,
+ const struct bpf_insn *insn, int idx)
+{
+ int start = idx + insn->imm + 1, subprog;
+
+ subprog = find_subprog(env, start);
+ if (subprog < 0) {
+ WARN_ONCE(1, "verifier bug. No program starts at insn %d\n",
+ start);
+ return -EFAULT;
+ }
+ return env->subprog_info[subprog].stack_depth;
+}
+#endif
+
+static int __check_buffer_access(struct bpf_verifier_env *env,
+ const char *buf_info,
+ const struct bpf_reg_state *reg,
+ int regno, int off, int size)
+{
+ if (off < 0) {
+ verbose(env,
+ "R%d invalid %s buffer access: off=%d, size=%d\n",
+ regno, buf_info, off, size);
+ return -EACCES;
+ }
+ if (!tnum_is_const(reg->var_off) || reg->var_off.value) {
+ char tn_buf[48];
+
+ tnum_strn(tn_buf, sizeof(tn_buf), reg->var_off);
+ verbose(env,
+ "R%d invalid variable buffer offset: off=%d, var_off=%s\n",
+ regno, off, tn_buf);
+ return -EACCES;
+ }
+
+ return 0;
+}
+
+static int check_tp_buffer_access(struct bpf_verifier_env *env,
+ const struct bpf_reg_state *reg,
+ int regno, int off, int size)
+{
+ int err;
+
+ err = __check_buffer_access(env, "tracepoint", reg, regno, off, size);
+ if (err)
+ return err;
+
+ if (off + size > env->prog->aux->max_tp_access)
+ env->prog->aux->max_tp_access = off + size;
+
+ return 0;
+}
+
+static int check_buffer_access(struct bpf_verifier_env *env,
+ const struct bpf_reg_state *reg,
+ int regno, int off, int size,
+ bool zero_size_allowed,
+ u32 *max_access)
+{
+ const char *buf_info = type_is_rdonly_mem(reg->type) ? "rdonly" : "rdwr";
+ int err;
+
+ err = __check_buffer_access(env, buf_info, reg, regno, off, size);
+ if (err)
+ return err;
+
+ if (off + size > *max_access)
+ *max_access = off + size;
+
+ return 0;
+}
+
+/* BPF architecture zero extends alu32 ops into 64-bit registesr */
+static void zext_32_to_64(struct bpf_reg_state *reg)
+{
+ reg->var_off = tnum_subreg(reg->var_off);
+ __reg_assign_32_into_64(reg);
+}
+
+/* truncate register to smaller size (in bytes)
+ * must be called with size < BPF_REG_SIZE
+ */
+static void coerce_reg_to_size(struct bpf_reg_state *reg, int size)
+{
+ u64 mask;
+
+ /* clear high bits in bit representation */
+ reg->var_off = tnum_cast(reg->var_off, size);
+
+ /* fix arithmetic bounds */
+ mask = ((u64)1 << (size * 8)) - 1;
+ if ((reg->umin_value & ~mask) == (reg->umax_value & ~mask)) {
+ reg->umin_value &= mask;
+ reg->umax_value &= mask;
+ } else {
+ reg->umin_value = 0;
+ reg->umax_value = mask;
+ }
+ reg->smin_value = reg->umin_value;
+ reg->smax_value = reg->umax_value;
+
+ /* If size is smaller than 32bit register the 32bit register
+ * values are also truncated so we push 64-bit bounds into
+ * 32-bit bounds. Above were truncated < 32-bits already.
+ */
+ if (size >= 4)
+ return;
+ __reg_combine_64_into_32(reg);
+}
+
+static void set_sext64_default_val(struct bpf_reg_state *reg, int size)
+{
+ if (size == 1) {
+ reg->smin_value = reg->s32_min_value = S8_MIN;
+ reg->smax_value = reg->s32_max_value = S8_MAX;
+ } else if (size == 2) {
+ reg->smin_value = reg->s32_min_value = S16_MIN;
+ reg->smax_value = reg->s32_max_value = S16_MAX;
+ } else {
+ /* size == 4 */
+ reg->smin_value = reg->s32_min_value = S32_MIN;
+ reg->smax_value = reg->s32_max_value = S32_MAX;
+ }
+ reg->umin_value = reg->u32_min_value = 0;
+ reg->umax_value = U64_MAX;
+ reg->u32_max_value = U32_MAX;
+ reg->var_off = tnum_unknown;
+}
+
+static void coerce_reg_to_size_sx(struct bpf_reg_state *reg, int size)
+{
+ s64 init_s64_max, init_s64_min, s64_max, s64_min, u64_cval;
+ u64 top_smax_value, top_smin_value;
+ u64 num_bits = size * 8;
+
+ if (tnum_is_const(reg->var_off)) {
+ u64_cval = reg->var_off.value;
+ if (size == 1)
+ reg->var_off = tnum_const((s8)u64_cval);
+ else if (size == 2)
+ reg->var_off = tnum_const((s16)u64_cval);
+ else
+ /* size == 4 */
+ reg->var_off = tnum_const((s32)u64_cval);
+
+ u64_cval = reg->var_off.value;
+ reg->smax_value = reg->smin_value = u64_cval;
+ reg->umax_value = reg->umin_value = u64_cval;
+ reg->s32_max_value = reg->s32_min_value = u64_cval;
+ reg->u32_max_value = reg->u32_min_value = u64_cval;
+ return;
+ }
+
+ top_smax_value = ((u64)reg->smax_value >> num_bits) << num_bits;
+ top_smin_value = ((u64)reg->smin_value >> num_bits) << num_bits;
+
+ if (top_smax_value != top_smin_value)
+ goto out;
+
+ /* find the s64_min and s64_min after sign extension */
+ if (size == 1) {
+ init_s64_max = (s8)reg->smax_value;
+ init_s64_min = (s8)reg->smin_value;
+ } else if (size == 2) {
+ init_s64_max = (s16)reg->smax_value;
+ init_s64_min = (s16)reg->smin_value;
+ } else {
+ init_s64_max = (s32)reg->smax_value;
+ init_s64_min = (s32)reg->smin_value;
+ }
+
+ s64_max = max(init_s64_max, init_s64_min);
+ s64_min = min(init_s64_max, init_s64_min);
+
+ /* both of s64_max/s64_min positive or negative */
+ if ((s64_max >= 0) == (s64_min >= 0)) {
+ reg->smin_value = reg->s32_min_value = s64_min;
+ reg->smax_value = reg->s32_max_value = s64_max;
+ reg->umin_value = reg->u32_min_value = s64_min;
+ reg->umax_value = reg->u32_max_value = s64_max;
+ reg->var_off = tnum_range(s64_min, s64_max);
+ return;
+ }
+
+out:
+ set_sext64_default_val(reg, size);
+}
+
+static void set_sext32_default_val(struct bpf_reg_state *reg, int size)
+{
+ if (size == 1) {
+ reg->s32_min_value = S8_MIN;
+ reg->s32_max_value = S8_MAX;
+ } else {
+ /* size == 2 */
+ reg->s32_min_value = S16_MIN;
+ reg->s32_max_value = S16_MAX;
+ }
+ reg->u32_min_value = 0;
+ reg->u32_max_value = U32_MAX;
+}
+
+static void coerce_subreg_to_size_sx(struct bpf_reg_state *reg, int size)
+{
+ s32 init_s32_max, init_s32_min, s32_max, s32_min, u32_val;
+ u32 top_smax_value, top_smin_value;
+ u32 num_bits = size * 8;
+
+ if (tnum_is_const(reg->var_off)) {
+ u32_val = reg->var_off.value;
+ if (size == 1)
+ reg->var_off = tnum_const((s8)u32_val);
+ else
+ reg->var_off = tnum_const((s16)u32_val);
+
+ u32_val = reg->var_off.value;
+ reg->s32_min_value = reg->s32_max_value = u32_val;
+ reg->u32_min_value = reg->u32_max_value = u32_val;
+ return;
+ }
+
+ top_smax_value = ((u32)reg->s32_max_value >> num_bits) << num_bits;
+ top_smin_value = ((u32)reg->s32_min_value >> num_bits) << num_bits;
+
+ if (top_smax_value != top_smin_value)
+ goto out;
+
+ /* find the s32_min and s32_min after sign extension */
+ if (size == 1) {
+ init_s32_max = (s8)reg->s32_max_value;
+ init_s32_min = (s8)reg->s32_min_value;
+ } else {
+ /* size == 2 */
+ init_s32_max = (s16)reg->s32_max_value;
+ init_s32_min = (s16)reg->s32_min_value;
+ }
+ s32_max = max(init_s32_max, init_s32_min);
+ s32_min = min(init_s32_max, init_s32_min);
+
+ if ((s32_min >= 0) == (s32_max >= 0)) {
+ reg->s32_min_value = s32_min;
+ reg->s32_max_value = s32_max;
+ reg->u32_min_value = (u32)s32_min;
+ reg->u32_max_value = (u32)s32_max;
+ return;
+ }
+
+out:
+ set_sext32_default_val(reg, size);
+}
+
+static bool bpf_map_is_rdonly(const struct bpf_map *map)
+{
+ /* A map is considered read-only if the following condition are true:
+ *
+ * 1) BPF program side cannot change any of the map content. The
+ * BPF_F_RDONLY_PROG flag is throughout the lifetime of a map
+ * and was set at map creation time.
+ * 2) The map value(s) have been initialized from user space by a
+ * loader and then "frozen", such that no new map update/delete
+ * operations from syscall side are possible for the rest of
+ * the map's lifetime from that point onwards.
+ * 3) Any parallel/pending map update/delete operations from syscall
+ * side have been completed. Only after that point, it's safe to
+ * assume that map value(s) are immutable.
+ */
+ return (map->map_flags & BPF_F_RDONLY_PROG) &&
+ READ_ONCE(map->frozen) &&
+ !bpf_map_write_active(map);
+}
+
+static int bpf_map_direct_read(struct bpf_map *map, int off, int size, u64 *val,
+ bool is_ldsx)
+{
+ void *ptr;
+ u64 addr;
+ int err;
+
+ err = map->ops->map_direct_value_addr(map, &addr, off);
+ if (err)
+ return err;
+ ptr = (void *)(long)addr + off;
+
+ switch (size) {
+ case sizeof(u8):
+ *val = is_ldsx ? (s64)*(s8 *)ptr : (u64)*(u8 *)ptr;
+ break;
+ case sizeof(u16):
+ *val = is_ldsx ? (s64)*(s16 *)ptr : (u64)*(u16 *)ptr;
+ break;
+ case sizeof(u32):
+ *val = is_ldsx ? (s64)*(s32 *)ptr : (u64)*(u32 *)ptr;
+ break;
+ case sizeof(u64):
+ *val = *(u64 *)ptr;
+ break;
+ default:
+ return -EINVAL;
+ }
+ return 0;
+}
+
+#define BTF_TYPE_SAFE_RCU(__type) __PASTE(__type, __safe_rcu)
+#define BTF_TYPE_SAFE_RCU_OR_NULL(__type) __PASTE(__type, __safe_rcu_or_null)
+#define BTF_TYPE_SAFE_TRUSTED(__type) __PASTE(__type, __safe_trusted)
+
+/*
+ * Allow list few fields as RCU trusted or full trusted.
+ * This logic doesn't allow mix tagging and will be removed once GCC supports
+ * btf_type_tag.
+ */
+
+/* RCU trusted: these fields are trusted in RCU CS and never NULL */
+BTF_TYPE_SAFE_RCU(struct task_struct) {
+ const cpumask_t *cpus_ptr;
+ struct css_set __rcu *cgroups;
+ struct task_struct __rcu *real_parent;
+ struct task_struct *group_leader;
+};
+
+BTF_TYPE_SAFE_RCU(struct cgroup) {
+ /* cgrp->kn is always accessible as documented in kernel/cgroup/cgroup.c */
+ struct kernfs_node *kn;
+};
+
+BTF_TYPE_SAFE_RCU(struct css_set) {
+ struct cgroup *dfl_cgrp;
+};
+
+/* RCU trusted: these fields are trusted in RCU CS and can be NULL */
+BTF_TYPE_SAFE_RCU_OR_NULL(struct mm_struct) {
+ struct file __rcu *exe_file;
+};
+
+/* skb->sk, req->sk are not RCU protected, but we mark them as such
+ * because bpf prog accessible sockets are SOCK_RCU_FREE.
+ */
+BTF_TYPE_SAFE_RCU_OR_NULL(struct sk_buff) {
+ struct sock *sk;
+};
+
+BTF_TYPE_SAFE_RCU_OR_NULL(struct request_sock) {
+ struct sock *sk;
+};
+
+/* full trusted: these fields are trusted even outside of RCU CS and never NULL */
+BTF_TYPE_SAFE_TRUSTED(struct bpf_iter_meta) {
+ struct seq_file *seq;
+};
+
+BTF_TYPE_SAFE_TRUSTED(struct bpf_iter__task) {
+ struct bpf_iter_meta *meta;
+ struct task_struct *task;
+};
+
+BTF_TYPE_SAFE_TRUSTED(struct linux_binprm) {
+ struct file *file;
+};
+
+BTF_TYPE_SAFE_TRUSTED(struct file) {
+ struct inode *f_inode;
+};
+
+BTF_TYPE_SAFE_TRUSTED(struct dentry) {
+ /* no negative dentry-s in places where bpf can see it */
+ struct inode *d_inode;
+};
+
+BTF_TYPE_SAFE_TRUSTED(struct socket) {
+ struct sock *sk;
+};
+
+static bool type_is_rcu(struct bpf_verifier_env *env,
+ struct bpf_reg_state *reg,
+ const char *field_name, u32 btf_id)
+{
+ BTF_TYPE_EMIT(BTF_TYPE_SAFE_RCU(struct task_struct));
+ BTF_TYPE_EMIT(BTF_TYPE_SAFE_RCU(struct cgroup));
+ BTF_TYPE_EMIT(BTF_TYPE_SAFE_RCU(struct css_set));
+
+ return btf_nested_type_is_trusted(&env->log, reg, field_name, btf_id, "__safe_rcu");
+}
+
+static bool type_is_rcu_or_null(struct bpf_verifier_env *env,
+ struct bpf_reg_state *reg,
+ const char *field_name, u32 btf_id)
+{
+ BTF_TYPE_EMIT(BTF_TYPE_SAFE_RCU_OR_NULL(struct mm_struct));
+ BTF_TYPE_EMIT(BTF_TYPE_SAFE_RCU_OR_NULL(struct sk_buff));
+ BTF_TYPE_EMIT(BTF_TYPE_SAFE_RCU_OR_NULL(struct request_sock));
+
+ return btf_nested_type_is_trusted(&env->log, reg, field_name, btf_id, "__safe_rcu_or_null");
+}
+
+static bool type_is_trusted(struct bpf_verifier_env *env,
+ struct bpf_reg_state *reg,
+ const char *field_name, u32 btf_id)
+{
+ BTF_TYPE_EMIT(BTF_TYPE_SAFE_TRUSTED(struct bpf_iter_meta));
+ BTF_TYPE_EMIT(BTF_TYPE_SAFE_TRUSTED(struct bpf_iter__task));
+ BTF_TYPE_EMIT(BTF_TYPE_SAFE_TRUSTED(struct linux_binprm));
+ BTF_TYPE_EMIT(BTF_TYPE_SAFE_TRUSTED(struct file));
+ BTF_TYPE_EMIT(BTF_TYPE_SAFE_TRUSTED(struct dentry));
+ BTF_TYPE_EMIT(BTF_TYPE_SAFE_TRUSTED(struct socket));
+
+ return btf_nested_type_is_trusted(&env->log, reg, field_name, btf_id, "__safe_trusted");
+}
+
+static int check_ptr_to_btf_access(struct bpf_verifier_env *env,
+ struct bpf_reg_state *regs,
+ int regno, int off, int size,
+ enum bpf_access_type atype,
+ int value_regno)
+{
+ struct bpf_reg_state *reg = regs + regno;
+ const struct btf_type *t = btf_type_by_id(reg->btf, reg->btf_id);
+ const char *tname = btf_name_by_offset(reg->btf, t->name_off);
+ const char *field_name = NULL;
+ enum bpf_type_flag flag = 0;
+ u32 btf_id = 0;
+ int ret;
+
+ if (!env->allow_ptr_leaks) {
+ verbose(env,
+ "'struct %s' access is allowed only to CAP_PERFMON and CAP_SYS_ADMIN\n",
+ tname);
+ return -EPERM;
+ }
+ if (!env->prog->gpl_compatible && btf_is_kernel(reg->btf)) {
+ verbose(env,
+ "Cannot access kernel 'struct %s' from non-GPL compatible program\n",
+ tname);
+ return -EINVAL;
+ }
+ if (off < 0) {
+ verbose(env,
+ "R%d is ptr_%s invalid negative access: off=%d\n",
+ regno, tname, off);
+ return -EACCES;
+ }
+ if (!tnum_is_const(reg->var_off) || reg->var_off.value) {
+ char tn_buf[48];
+
+ tnum_strn(tn_buf, sizeof(tn_buf), reg->var_off);
+ verbose(env,
+ "R%d is ptr_%s invalid variable offset: off=%d, var_off=%s\n",
+ regno, tname, off, tn_buf);
+ return -EACCES;
+ }
+
+ if (reg->type & MEM_USER) {
+ verbose(env,
+ "R%d is ptr_%s access user memory: off=%d\n",
+ regno, tname, off);
+ return -EACCES;
+ }
+
+ if (reg->type & MEM_PERCPU) {
+ verbose(env,
+ "R%d is ptr_%s access percpu memory: off=%d\n",
+ regno, tname, off);
+ return -EACCES;
+ }
+
+ if (env->ops->btf_struct_access && !type_is_alloc(reg->type) && atype == BPF_WRITE) {
+ if (!btf_is_kernel(reg->btf)) {
+ verbose(env, "verifier internal error: reg->btf must be kernel btf\n");
+ return -EFAULT;
+ }
+ ret = env->ops->btf_struct_access(&env->log, reg, off, size);
+ } else {
+ /* Writes are permitted with default btf_struct_access for
+ * program allocated objects (which always have ref_obj_id > 0),
+ * but not for untrusted PTR_TO_BTF_ID | MEM_ALLOC.
+ */
+ if (atype != BPF_READ && !type_is_ptr_alloc_obj(reg->type)) {
+ verbose(env, "only read is supported\n");
+ return -EACCES;
+ }
+
+ if (type_is_alloc(reg->type) && !type_is_non_owning_ref(reg->type) &&
+ !reg->ref_obj_id) {
+ verbose(env, "verifier internal error: ref_obj_id for allocated object must be non-zero\n");
+ return -EFAULT;
+ }
+
+ ret = btf_struct_access(&env->log, reg, off, size, atype, &btf_id, &flag, &field_name);
+ }
+
+ if (ret < 0)
+ return ret;
+
+ if (ret != PTR_TO_BTF_ID) {
+ /* just mark; */
+
+ } else if (type_flag(reg->type) & PTR_UNTRUSTED) {
+ /* If this is an untrusted pointer, all pointers formed by walking it
+ * also inherit the untrusted flag.
+ */
+ flag = PTR_UNTRUSTED;
+
+ } else if (is_trusted_reg(reg) || is_rcu_reg(reg)) {
+ /* By default any pointer obtained from walking a trusted pointer is no
+ * longer trusted, unless the field being accessed has explicitly been
+ * marked as inheriting its parent's state of trust (either full or RCU).
+ * For example:
+ * 'cgroups' pointer is untrusted if task->cgroups dereference
+ * happened in a sleepable program outside of bpf_rcu_read_lock()
+ * section. In a non-sleepable program it's trusted while in RCU CS (aka MEM_RCU).
+ * Note bpf_rcu_read_unlock() converts MEM_RCU pointers to PTR_UNTRUSTED.
+ *
+ * A regular RCU-protected pointer with __rcu tag can also be deemed
+ * trusted if we are in an RCU CS. Such pointer can be NULL.
+ */
+ if (type_is_trusted(env, reg, field_name, btf_id)) {
+ flag |= PTR_TRUSTED;
+ } else if (in_rcu_cs(env) && !type_may_be_null(reg->type)) {
+ if (type_is_rcu(env, reg, field_name, btf_id)) {
+ /* ignore __rcu tag and mark it MEM_RCU */
+ flag |= MEM_RCU;
+ } else if (flag & MEM_RCU ||
+ type_is_rcu_or_null(env, reg, field_name, btf_id)) {
+ /* __rcu tagged pointers can be NULL */
+ flag |= MEM_RCU | PTR_MAYBE_NULL;
+
+ /* We always trust them */
+ if (type_is_rcu_or_null(env, reg, field_name, btf_id) &&
+ flag & PTR_UNTRUSTED)
+ flag &= ~PTR_UNTRUSTED;
+ } else if (flag & (MEM_PERCPU | MEM_USER)) {
+ /* keep as-is */
+ } else {
+ /* walking unknown pointers yields old deprecated PTR_TO_BTF_ID */
+ clear_trusted_flags(&flag);
+ }
+ } else {
+ /*
+ * If not in RCU CS or MEM_RCU pointer can be NULL then
+ * aggressively mark as untrusted otherwise such
+ * pointers will be plain PTR_TO_BTF_ID without flags
+ * and will be allowed to be passed into helpers for
+ * compat reasons.
+ */
+ flag = PTR_UNTRUSTED;
+ }
+ } else {
+ /* Old compat. Deprecated */
+ clear_trusted_flags(&flag);
+ }
+
+ if (atype == BPF_READ && value_regno >= 0)
+ mark_btf_ld_reg(env, regs, value_regno, ret, reg->btf, btf_id, flag);
+
+ return 0;
+}
+
+static int check_ptr_to_map_access(struct bpf_verifier_env *env,
+ struct bpf_reg_state *regs,
+ int regno, int off, int size,
+ enum bpf_access_type atype,
+ int value_regno)
+{
+ struct bpf_reg_state *reg = regs + regno;
+ struct bpf_map *map = reg->map_ptr;
+ struct bpf_reg_state map_reg;
+ enum bpf_type_flag flag = 0;
+ const struct btf_type *t;
+ const char *tname;
+ u32 btf_id;
+ int ret;
+
+ if (!btf_vmlinux) {
+ verbose(env, "map_ptr access not supported without CONFIG_DEBUG_INFO_BTF\n");
+ return -ENOTSUPP;
+ }
+
+ if (!map->ops->map_btf_id || !*map->ops->map_btf_id) {
+ verbose(env, "map_ptr access not supported for map type %d\n",
+ map->map_type);
+ return -ENOTSUPP;
+ }
+
+ t = btf_type_by_id(btf_vmlinux, *map->ops->map_btf_id);
+ tname = btf_name_by_offset(btf_vmlinux, t->name_off);
+
+ if (!env->allow_ptr_leaks) {
+ verbose(env,
+ "'struct %s' access is allowed only to CAP_PERFMON and CAP_SYS_ADMIN\n",
+ tname);
+ return -EPERM;
+ }
+
+ if (off < 0) {
+ verbose(env, "R%d is %s invalid negative access: off=%d\n",
+ regno, tname, off);
+ return -EACCES;
+ }
+
+ if (atype != BPF_READ) {
+ verbose(env, "only read from %s is supported\n", tname);
+ return -EACCES;
+ }
+
+ /* Simulate access to a PTR_TO_BTF_ID */
+ memset(&map_reg, 0, sizeof(map_reg));
+ mark_btf_ld_reg(env, &map_reg, 0, PTR_TO_BTF_ID, btf_vmlinux, *map->ops->map_btf_id, 0);
+ ret = btf_struct_access(&env->log, &map_reg, off, size, atype, &btf_id, &flag, NULL);
+ if (ret < 0)
+ return ret;
+
+ if (value_regno >= 0)
+ mark_btf_ld_reg(env, regs, value_regno, ret, btf_vmlinux, btf_id, flag);
+
+ return 0;
+}
+
+/* Check that the stack access at the given offset is within bounds. The
+ * maximum valid offset is -1.
+ *
+ * The minimum valid offset is -MAX_BPF_STACK for writes, and
+ * -state->allocated_stack for reads.
+ */
+static int check_stack_slot_within_bounds(struct bpf_verifier_env *env,
+ s64 off,
+ struct bpf_func_state *state,
+ enum bpf_access_type t)
+{
+ int min_valid_off;
+
+ if (t == BPF_WRITE || env->allow_uninit_stack)
+ min_valid_off = -MAX_BPF_STACK;
+ else
+ min_valid_off = -state->allocated_stack;
+
+ if (off < min_valid_off || off > -1)
+ return -EACCES;
+ return 0;
+}
+
+/* Check that the stack access at 'regno + off' falls within the maximum stack
+ * bounds.
+ *
+ * 'off' includes `regno->offset`, but not its dynamic part (if any).
+ */
+static int check_stack_access_within_bounds(
+ struct bpf_verifier_env *env,
+ int regno, int off, int access_size,
+ enum bpf_access_src src, enum bpf_access_type type)
+{
+ struct bpf_reg_state *regs = cur_regs(env);
+ struct bpf_reg_state *reg = regs + regno;
+ struct bpf_func_state *state = func(env, reg);
+ s64 min_off, max_off;
+ int err;
+ char *err_extra;
+
+ if (src == ACCESS_HELPER)
+ /* We don't know if helpers are reading or writing (or both). */
+ err_extra = " indirect access to";
+ else if (type == BPF_READ)
+ err_extra = " read from";
+ else
+ err_extra = " write to";
+
+ if (tnum_is_const(reg->var_off)) {
+ min_off = (s64)reg->var_off.value + off;
+ max_off = min_off + access_size;
+ } else {
+ if (reg->smax_value >= BPF_MAX_VAR_OFF ||
+ reg->smin_value <= -BPF_MAX_VAR_OFF) {
+ verbose(env, "invalid unbounded variable-offset%s stack R%d\n",
+ err_extra, regno);
+ return -EACCES;
+ }
+ min_off = reg->smin_value + off;
+ max_off = reg->smax_value + off + access_size;
+ }
+
+ err = check_stack_slot_within_bounds(env, min_off, state, type);
+ if (!err && max_off > 0)
+ err = -EINVAL; /* out of stack access into non-negative offsets */
+
+ if (err) {
+ if (tnum_is_const(reg->var_off)) {
+ verbose(env, "invalid%s stack R%d off=%d size=%d\n",
+ err_extra, regno, off, access_size);
+ } else {
+ char tn_buf[48];
+
+ tnum_strn(tn_buf, sizeof(tn_buf), reg->var_off);
+ verbose(env, "invalid variable-offset%s stack R%d var_off=%s size=%d\n",
+ err_extra, regno, tn_buf, access_size);
+ }
+ return err;
+ }
+
+ return grow_stack_state(env, state, round_up(-min_off, BPF_REG_SIZE));
+}
+
+/* check whether memory at (regno + off) is accessible for t = (read | write)
+ * if t==write, value_regno is a register which value is stored into memory
+ * if t==read, value_regno is a register which will receive the value from memory
+ * if t==write && value_regno==-1, some unknown value is stored into memory
+ * if t==read && value_regno==-1, don't care what we read from memory
+ */
+static int check_mem_access(struct bpf_verifier_env *env, int insn_idx, u32 regno,
+ int off, int bpf_size, enum bpf_access_type t,
+ int value_regno, bool strict_alignment_once, bool is_ldsx)
+{
+ struct bpf_reg_state *regs = cur_regs(env);
+ struct bpf_reg_state *reg = regs + regno;
+ int size, err = 0;
+
+ size = bpf_size_to_bytes(bpf_size);
+ if (size < 0)
+ return size;
+
+ /* alignment checks will add in reg->off themselves */
+ err = check_ptr_alignment(env, reg, off, size, strict_alignment_once);
+ if (err)
+ return err;
+
+ /* for access checks, reg->off is just part of off */
+ off += reg->off;
+
+ if (reg->type == PTR_TO_MAP_KEY) {
+ if (t == BPF_WRITE) {
+ verbose(env, "write to change key R%d not allowed\n", regno);
+ return -EACCES;
+ }
+
+ err = check_mem_region_access(env, regno, off, size,
+ reg->map_ptr->key_size, false);
+ if (err)
+ return err;
+ if (value_regno >= 0)
+ mark_reg_unknown(env, regs, value_regno);
+ } else if (reg->type == PTR_TO_MAP_VALUE) {
+ struct btf_field *kptr_field = NULL;
+
+ if (t == BPF_WRITE && value_regno >= 0 &&
+ is_pointer_value(env, value_regno)) {
+ verbose(env, "R%d leaks addr into map\n", value_regno);
+ return -EACCES;
+ }
+ err = check_map_access_type(env, regno, off, size, t);
+ if (err)
+ return err;
+ err = check_map_access(env, regno, off, size, false, ACCESS_DIRECT);
+ if (err)
+ return err;
+ if (tnum_is_const(reg->var_off))
+ kptr_field = btf_record_find(reg->map_ptr->record,
+ off + reg->var_off.value, BPF_KPTR);
+ if (kptr_field) {
+ err = check_map_kptr_access(env, regno, value_regno, insn_idx, kptr_field);
+ } else if (t == BPF_READ && value_regno >= 0) {
+ struct bpf_map *map = reg->map_ptr;
+
+ /* if map is read-only, track its contents as scalars */
+ if (tnum_is_const(reg->var_off) &&
+ bpf_map_is_rdonly(map) &&
+ map->ops->map_direct_value_addr) {
+ int map_off = off + reg->var_off.value;
+ u64 val = 0;
+
+ err = bpf_map_direct_read(map, map_off, size,
+ &val, is_ldsx);
+ if (err)
+ return err;
+
+ regs[value_regno].type = SCALAR_VALUE;
+ __mark_reg_known(&regs[value_regno], val);
+ } else {
+ mark_reg_unknown(env, regs, value_regno);
+ }
+ }
+ } else if (base_type(reg->type) == PTR_TO_MEM) {
+ bool rdonly_mem = type_is_rdonly_mem(reg->type);
+
+ if (type_may_be_null(reg->type)) {
+ verbose(env, "R%d invalid mem access '%s'\n", regno,
+ reg_type_str(env, reg->type));
+ return -EACCES;
+ }
+
+ if (t == BPF_WRITE && rdonly_mem) {
+ verbose(env, "R%d cannot write into %s\n",
+ regno, reg_type_str(env, reg->type));
+ return -EACCES;
+ }
+
+ if (t == BPF_WRITE && value_regno >= 0 &&
+ is_pointer_value(env, value_regno)) {
+ verbose(env, "R%d leaks addr into mem\n", value_regno);
+ return -EACCES;
+ }
+
+ err = check_mem_region_access(env, regno, off, size,
+ reg->mem_size, false);
+ if (!err && value_regno >= 0 && (t == BPF_READ || rdonly_mem))
+ mark_reg_unknown(env, regs, value_regno);
+ } else if (reg->type == PTR_TO_CTX) {
+ enum bpf_reg_type reg_type = SCALAR_VALUE;
+ struct btf *btf = NULL;
+ u32 btf_id = 0;
+
+ if (t == BPF_WRITE && value_regno >= 0 &&
+ is_pointer_value(env, value_regno)) {
+ verbose(env, "R%d leaks addr into ctx\n", value_regno);
+ return -EACCES;
+ }
+
+ err = check_ptr_off_reg(env, reg, regno);
+ if (err < 0)
+ return err;
+
+ err = check_ctx_access(env, insn_idx, off, size, t, &reg_type, &btf,
+ &btf_id);
+ if (err)
+ verbose_linfo(env, insn_idx, "; ");
+ if (!err && t == BPF_READ && value_regno >= 0) {
+ /* ctx access returns either a scalar, or a
+ * PTR_TO_PACKET[_META,_END]. In the latter
+ * case, we know the offset is zero.
+ */
+ if (reg_type == SCALAR_VALUE) {
+ mark_reg_unknown(env, regs, value_regno);
+ } else {
+ mark_reg_known_zero(env, regs,
+ value_regno);
+ if (type_may_be_null(reg_type))
+ regs[value_regno].id = ++env->id_gen;
+ /* A load of ctx field could have different
+ * actual load size with the one encoded in the
+ * insn. When the dst is PTR, it is for sure not
+ * a sub-register.
+ */
+ regs[value_regno].subreg_def = DEF_NOT_SUBREG;
+ if (base_type(reg_type) == PTR_TO_BTF_ID) {
+ regs[value_regno].btf = btf;
+ regs[value_regno].btf_id = btf_id;
+ }
+ }
+ regs[value_regno].type = reg_type;
+ }
+
+ } else if (reg->type == PTR_TO_STACK) {
+ /* Basic bounds checks. */
+ err = check_stack_access_within_bounds(env, regno, off, size, ACCESS_DIRECT, t);
+ if (err)
+ return err;
+
+ if (t == BPF_READ)
+ err = check_stack_read(env, regno, off, size,
+ value_regno);
+ else
+ err = check_stack_write(env, regno, off, size,
+ value_regno, insn_idx);
+ } else if (reg_is_pkt_pointer(reg)) {
+ if (t == BPF_WRITE && !may_access_direct_pkt_data(env, NULL, t)) {
+ verbose(env, "cannot write into packet\n");
+ return -EACCES;
+ }
+ if (t == BPF_WRITE && value_regno >= 0 &&
+ is_pointer_value(env, value_regno)) {
+ verbose(env, "R%d leaks addr into packet\n",
+ value_regno);
+ return -EACCES;
+ }
+ err = check_packet_access(env, regno, off, size, false);
+ if (!err && t == BPF_READ && value_regno >= 0)
+ mark_reg_unknown(env, regs, value_regno);
+ } else if (reg->type == PTR_TO_FLOW_KEYS) {
+ if (t == BPF_WRITE && value_regno >= 0 &&
+ is_pointer_value(env, value_regno)) {
+ verbose(env, "R%d leaks addr into flow keys\n",
+ value_regno);
+ return -EACCES;
+ }
+
+ err = check_flow_keys_access(env, off, size);
+ if (!err && t == BPF_READ && value_regno >= 0)
+ mark_reg_unknown(env, regs, value_regno);
+ } else if (type_is_sk_pointer(reg->type)) {
+ if (t == BPF_WRITE) {
+ verbose(env, "R%d cannot write into %s\n",
+ regno, reg_type_str(env, reg->type));
+ return -EACCES;
+ }
+ err = check_sock_access(env, insn_idx, regno, off, size, t);
+ if (!err && value_regno >= 0)
+ mark_reg_unknown(env, regs, value_regno);
+ } else if (reg->type == PTR_TO_TP_BUFFER) {
+ err = check_tp_buffer_access(env, reg, regno, off, size);
+ if (!err && t == BPF_READ && value_regno >= 0)
+ mark_reg_unknown(env, regs, value_regno);
+ } else if (base_type(reg->type) == PTR_TO_BTF_ID &&
+ !type_may_be_null(reg->type)) {
+ err = check_ptr_to_btf_access(env, regs, regno, off, size, t,
+ value_regno);
+ } else if (reg->type == CONST_PTR_TO_MAP) {
+ err = check_ptr_to_map_access(env, regs, regno, off, size, t,
+ value_regno);
+ } else if (base_type(reg->type) == PTR_TO_BUF) {
+ bool rdonly_mem = type_is_rdonly_mem(reg->type);
+ u32 *max_access;
+
+ if (rdonly_mem) {
+ if (t == BPF_WRITE) {
+ verbose(env, "R%d cannot write into %s\n",
+ regno, reg_type_str(env, reg->type));
+ return -EACCES;
+ }
+ max_access = &env->prog->aux->max_rdonly_access;
+ } else {
+ max_access = &env->prog->aux->max_rdwr_access;
+ }
+
+ err = check_buffer_access(env, reg, regno, off, size, false,
+ max_access);
+
+ if (!err && value_regno >= 0 && (rdonly_mem || t == BPF_READ))
+ mark_reg_unknown(env, regs, value_regno);
+ } else {
+ verbose(env, "R%d invalid mem access '%s'\n", regno,
+ reg_type_str(env, reg->type));
+ return -EACCES;
+ }
+
+ if (!err && size < BPF_REG_SIZE && value_regno >= 0 && t == BPF_READ &&
+ regs[value_regno].type == SCALAR_VALUE) {
+ if (!is_ldsx)
+ /* b/h/w load zero-extends, mark upper bits as known 0 */
+ coerce_reg_to_size(&regs[value_regno], size);
+ else
+ coerce_reg_to_size_sx(&regs[value_regno], size);
+ }
+ return err;
+}
+
+static int check_atomic(struct bpf_verifier_env *env, int insn_idx, struct bpf_insn *insn)
+{
+ int load_reg;
+ int err;
+
+ switch (insn->imm) {
+ case BPF_ADD:
+ case BPF_ADD | BPF_FETCH:
+ case BPF_AND:
+ case BPF_AND | BPF_FETCH:
+ case BPF_OR:
+ case BPF_OR | BPF_FETCH:
+ case BPF_XOR:
+ case BPF_XOR | BPF_FETCH:
+ case BPF_XCHG:
+ case BPF_CMPXCHG:
+ break;
+ default:
+ verbose(env, "BPF_ATOMIC uses invalid atomic opcode %02x\n", insn->imm);
+ return -EINVAL;
+ }
+
+ if (BPF_SIZE(insn->code) != BPF_W && BPF_SIZE(insn->code) != BPF_DW) {
+ verbose(env, "invalid atomic operand size\n");
+ return -EINVAL;
+ }
+
+ /* check src1 operand */
+ err = check_reg_arg(env, insn->src_reg, SRC_OP);
+ if (err)
+ return err;
+
+ /* check src2 operand */
+ err = check_reg_arg(env, insn->dst_reg, SRC_OP);
+ if (err)
+ return err;
+
+ if (insn->imm == BPF_CMPXCHG) {
+ /* Check comparison of R0 with memory location */
+ const u32 aux_reg = BPF_REG_0;
+
+ err = check_reg_arg(env, aux_reg, SRC_OP);
+ if (err)
+ return err;
+
+ if (is_pointer_value(env, aux_reg)) {
+ verbose(env, "R%d leaks addr into mem\n", aux_reg);
+ return -EACCES;
+ }
+ }
+
+ if (is_pointer_value(env, insn->src_reg)) {
+ verbose(env, "R%d leaks addr into mem\n", insn->src_reg);
+ return -EACCES;
+ }
+
+ if (is_ctx_reg(env, insn->dst_reg) ||
+ is_pkt_reg(env, insn->dst_reg) ||
+ is_flow_key_reg(env, insn->dst_reg) ||
+ is_sk_reg(env, insn->dst_reg)) {
+ verbose(env, "BPF_ATOMIC stores into R%d %s is not allowed\n",
+ insn->dst_reg,
+ reg_type_str(env, reg_state(env, insn->dst_reg)->type));
+ return -EACCES;
+ }
+
+ if (insn->imm & BPF_FETCH) {
+ if (insn->imm == BPF_CMPXCHG)
+ load_reg = BPF_REG_0;
+ else
+ load_reg = insn->src_reg;
+
+ /* check and record load of old value */
+ err = check_reg_arg(env, load_reg, DST_OP);
+ if (err)
+ return err;
+ } else {
+ /* This instruction accesses a memory location but doesn't
+ * actually load it into a register.
+ */
+ load_reg = -1;
+ }
+
+ /* Check whether we can read the memory, with second call for fetch
+ * case to simulate the register fill.
+ */
+ err = check_mem_access(env, insn_idx, insn->dst_reg, insn->off,
+ BPF_SIZE(insn->code), BPF_READ, -1, true, false);
+ if (!err && load_reg >= 0)
+ err = check_mem_access(env, insn_idx, insn->dst_reg, insn->off,
+ BPF_SIZE(insn->code), BPF_READ, load_reg,
+ true, false);
+ if (err)
+ return err;
+
+ /* Check whether we can write into the same memory. */
+ err = check_mem_access(env, insn_idx, insn->dst_reg, insn->off,
+ BPF_SIZE(insn->code), BPF_WRITE, -1, true, false);
+ if (err)
+ return err;
+
+ return 0;
+}
+
+/* When register 'regno' is used to read the stack (either directly or through
+ * a helper function) make sure that it's within stack boundary and, depending
+ * on the access type and privileges, that all elements of the stack are
+ * initialized.
+ *
+ * 'off' includes 'regno->off', but not its dynamic part (if any).
+ *
+ * All registers that have been spilled on the stack in the slots within the
+ * read offsets are marked as read.
+ */
+static int check_stack_range_initialized(
+ struct bpf_verifier_env *env, int regno, int off,
+ int access_size, bool zero_size_allowed,
+ enum bpf_access_src type, struct bpf_call_arg_meta *meta)
+{
+ struct bpf_reg_state *reg = reg_state(env, regno);
+ struct bpf_func_state *state = func(env, reg);
+ int err, min_off, max_off, i, j, slot, spi;
+ char *err_extra = type == ACCESS_HELPER ? " indirect" : "";
+ enum bpf_access_type bounds_check_type;
+ /* Some accesses can write anything into the stack, others are
+ * read-only.
+ */
+ bool clobber = false;
+
+ if (access_size == 0 && !zero_size_allowed) {
+ verbose(env, "invalid zero-sized read\n");
+ return -EACCES;
+ }
+
+ if (type == ACCESS_HELPER) {
+ /* The bounds checks for writes are more permissive than for
+ * reads. However, if raw_mode is not set, we'll do extra
+ * checks below.
+ */
+ bounds_check_type = BPF_WRITE;
+ clobber = true;
+ } else {
+ bounds_check_type = BPF_READ;
+ }
+ err = check_stack_access_within_bounds(env, regno, off, access_size,
+ type, bounds_check_type);
+ if (err)
+ return err;
+
+
+ if (tnum_is_const(reg->var_off)) {
+ min_off = max_off = reg->var_off.value + off;
+ } else {
+ /* Variable offset is prohibited for unprivileged mode for
+ * simplicity since it requires corresponding support in
+ * Spectre masking for stack ALU.
+ * See also retrieve_ptr_limit().
+ */
+ if (!env->bypass_spec_v1) {
+ char tn_buf[48];
+
+ tnum_strn(tn_buf, sizeof(tn_buf), reg->var_off);
+ verbose(env, "R%d%s variable offset stack access prohibited for !root, var_off=%s\n",
+ regno, err_extra, tn_buf);
+ return -EACCES;
+ }
+ /* Only initialized buffer on stack is allowed to be accessed
+ * with variable offset. With uninitialized buffer it's hard to
+ * guarantee that whole memory is marked as initialized on
+ * helper return since specific bounds are unknown what may
+ * cause uninitialized stack leaking.
+ */
+ if (meta && meta->raw_mode)
+ meta = NULL;
+
+ min_off = reg->smin_value + off;
+ max_off = reg->smax_value + off;
+ }
+
+ if (meta && meta->raw_mode) {
+ /* Ensure we won't be overwriting dynptrs when simulating byte
+ * by byte access in check_helper_call using meta.access_size.
+ * This would be a problem if we have a helper in the future
+ * which takes:
+ *
+ * helper(uninit_mem, len, dynptr)
+ *
+ * Now, uninint_mem may overlap with dynptr pointer. Hence, it
+ * may end up writing to dynptr itself when touching memory from
+ * arg 1. This can be relaxed on a case by case basis for known
+ * safe cases, but reject due to the possibilitiy of aliasing by
+ * default.
+ */
+ for (i = min_off; i < max_off + access_size; i++) {
+ int stack_off = -i - 1;
+
+ spi = __get_spi(i);
+ /* raw_mode may write past allocated_stack */
+ if (state->allocated_stack <= stack_off)
+ continue;
+ if (state->stack[spi].slot_type[stack_off % BPF_REG_SIZE] == STACK_DYNPTR) {
+ verbose(env, "potential write to dynptr at off=%d disallowed\n", i);
+ return -EACCES;
+ }
+ }
+ meta->access_size = access_size;
+ meta->regno = regno;
+ return 0;
+ }
+
+ for (i = min_off; i < max_off + access_size; i++) {
+ u8 *stype;
+
+ slot = -i - 1;
+ spi = slot / BPF_REG_SIZE;
+ if (state->allocated_stack <= slot) {
+ verbose(env, "verifier bug: allocated_stack too small");
+ return -EFAULT;
+ }
+
+ stype = &state->stack[spi].slot_type[slot % BPF_REG_SIZE];
+ if (*stype == STACK_MISC)
+ goto mark;
+ if ((*stype == STACK_ZERO) ||
+ (*stype == STACK_INVALID && env->allow_uninit_stack)) {
+ if (clobber) {
+ /* helper can write anything into the stack */
+ *stype = STACK_MISC;
+ }
+ goto mark;
+ }
+
+ if (is_spilled_reg(&state->stack[spi]) &&
+ (state->stack[spi].spilled_ptr.type == SCALAR_VALUE ||
+ env->allow_ptr_leaks)) {
+ if (clobber) {
+ __mark_reg_unknown(env, &state->stack[spi].spilled_ptr);
+ for (j = 0; j < BPF_REG_SIZE; j++)
+ scrub_spilled_slot(&state->stack[spi].slot_type[j]);
+ }
+ goto mark;
+ }
+
+ if (tnum_is_const(reg->var_off)) {
+ verbose(env, "invalid%s read from stack R%d off %d+%d size %d\n",
+ err_extra, regno, min_off, i - min_off, access_size);
+ } else {
+ char tn_buf[48];
+
+ tnum_strn(tn_buf, sizeof(tn_buf), reg->var_off);
+ verbose(env, "invalid%s read from stack R%d var_off %s+%d size %d\n",
+ err_extra, regno, tn_buf, i - min_off, access_size);
+ }
+ return -EACCES;
+mark:
+ /* reading any byte out of 8-byte 'spill_slot' will cause
+ * the whole slot to be marked as 'read'
+ */
+ mark_reg_read(env, &state->stack[spi].spilled_ptr,
+ state->stack[spi].spilled_ptr.parent,
+ REG_LIVE_READ64);
+ /* We do not set REG_LIVE_WRITTEN for stack slot, as we can not
+ * be sure that whether stack slot is written to or not. Hence,
+ * we must still conservatively propagate reads upwards even if
+ * helper may write to the entire memory range.
+ */
+ }
+ return 0;
+}
+
+static int check_helper_mem_access(struct bpf_verifier_env *env, int regno,
+ int access_size, bool zero_size_allowed,
+ struct bpf_call_arg_meta *meta)
+{
+ struct bpf_reg_state *regs = cur_regs(env), *reg = &regs[regno];
+ u32 *max_access;
+
+ switch (base_type(reg->type)) {
+ case PTR_TO_PACKET:
+ case PTR_TO_PACKET_META:
+ return check_packet_access(env, regno, reg->off, access_size,
+ zero_size_allowed);
+ case PTR_TO_MAP_KEY:
+ if (meta && meta->raw_mode) {
+ verbose(env, "R%d cannot write into %s\n", regno,
+ reg_type_str(env, reg->type));
+ return -EACCES;
+ }
+ return check_mem_region_access(env, regno, reg->off, access_size,
+ reg->map_ptr->key_size, false);
+ case PTR_TO_MAP_VALUE:
+ if (check_map_access_type(env, regno, reg->off, access_size,
+ meta && meta->raw_mode ? BPF_WRITE :
+ BPF_READ))
+ return -EACCES;
+ return check_map_access(env, regno, reg->off, access_size,
+ zero_size_allowed, ACCESS_HELPER);
+ case PTR_TO_MEM:
+ if (type_is_rdonly_mem(reg->type)) {
+ if (meta && meta->raw_mode) {
+ verbose(env, "R%d cannot write into %s\n", regno,
+ reg_type_str(env, reg->type));
+ return -EACCES;
+ }
+ }
+ return check_mem_region_access(env, regno, reg->off,
+ access_size, reg->mem_size,
+ zero_size_allowed);
+ case PTR_TO_BUF:
+ if (type_is_rdonly_mem(reg->type)) {
+ if (meta && meta->raw_mode) {
+ verbose(env, "R%d cannot write into %s\n", regno,
+ reg_type_str(env, reg->type));
+ return -EACCES;
+ }
+
+ max_access = &env->prog->aux->max_rdonly_access;
+ } else {
+ max_access = &env->prog->aux->max_rdwr_access;
+ }
+ return check_buffer_access(env, reg, regno, reg->off,
+ access_size, zero_size_allowed,
+ max_access);
+ case PTR_TO_STACK:
+ return check_stack_range_initialized(
+ env,
+ regno, reg->off, access_size,
+ zero_size_allowed, ACCESS_HELPER, meta);
+ case PTR_TO_BTF_ID:
+ return check_ptr_to_btf_access(env, regs, regno, reg->off,
+ access_size, BPF_READ, -1);
+ case PTR_TO_CTX:
+ /* in case the function doesn't know how to access the context,
+ * (because we are in a program of type SYSCALL for example), we
+ * can not statically check its size.
+ * Dynamically check it now.
+ */
+ if (!env->ops->convert_ctx_access) {
+ enum bpf_access_type atype = meta && meta->raw_mode ? BPF_WRITE : BPF_READ;
+ int offset = access_size - 1;
+
+ /* Allow zero-byte read from PTR_TO_CTX */
+ if (access_size == 0)
+ return zero_size_allowed ? 0 : -EACCES;
+
+ return check_mem_access(env, env->insn_idx, regno, offset, BPF_B,
+ atype, -1, false, false);
+ }
+
+ fallthrough;
+ default: /* scalar_value or invalid ptr */
+ /* Allow zero-byte read from NULL, regardless of pointer type */
+ if (zero_size_allowed && access_size == 0 &&
+ register_is_null(reg))
+ return 0;
+
+ verbose(env, "R%d type=%s ", regno,
+ reg_type_str(env, reg->type));
+ verbose(env, "expected=%s\n", reg_type_str(env, PTR_TO_STACK));
+ return -EACCES;
+ }
+}
+
+static int check_mem_size_reg(struct bpf_verifier_env *env,
+ struct bpf_reg_state *reg, u32 regno,
+ bool zero_size_allowed,
+ struct bpf_call_arg_meta *meta)
+{
+ int err;
+
+ /* This is used to refine r0 return value bounds for helpers
+ * that enforce this value as an upper bound on return values.
+ * See do_refine_retval_range() for helpers that can refine
+ * the return value. C type of helper is u32 so we pull register
+ * bound from umax_value however, if negative verifier errors
+ * out. Only upper bounds can be learned because retval is an
+ * int type and negative retvals are allowed.
+ */
+ meta->msize_max_value = reg->umax_value;
+
+ /* The register is SCALAR_VALUE; the access check
+ * happens using its boundaries.
+ */
+ if (!tnum_is_const(reg->var_off))
+ /* For unprivileged variable accesses, disable raw
+ * mode so that the program is required to
+ * initialize all the memory that the helper could
+ * just partially fill up.
+ */
+ meta = NULL;
+
+ if (reg->smin_value < 0) {
+ verbose(env, "R%d min value is negative, either use unsigned or 'var &= const'\n",
+ regno);
+ return -EACCES;
+ }
+
+ if (reg->umin_value == 0) {
+ err = check_helper_mem_access(env, regno - 1, 0,
+ zero_size_allowed,
+ meta);
+ if (err)
+ return err;
+ }
+
+ if (reg->umax_value >= BPF_MAX_VAR_SIZ) {
+ verbose(env, "R%d unbounded memory access, use 'var &= const' or 'if (var < const)'\n",
+ regno);
+ return -EACCES;
+ }
+ err = check_helper_mem_access(env, regno - 1,
+ reg->umax_value,
+ zero_size_allowed, meta);
+ if (!err)
+ err = mark_chain_precision(env, regno);
+ return err;
+}
+
+int check_mem_reg(struct bpf_verifier_env *env, struct bpf_reg_state *reg,
+ u32 regno, u32 mem_size)
+{
+ bool may_be_null = type_may_be_null(reg->type);
+ struct bpf_reg_state saved_reg;
+ struct bpf_call_arg_meta meta;
+ int err;
+
+ if (register_is_null(reg))
+ return 0;
+
+ memset(&meta, 0, sizeof(meta));
+ /* Assuming that the register contains a value check if the memory
+ * access is safe. Temporarily save and restore the register's state as
+ * the conversion shouldn't be visible to a caller.
+ */
+ if (may_be_null) {
+ saved_reg = *reg;
+ mark_ptr_not_null_reg(reg);
+ }
+
+ err = check_helper_mem_access(env, regno, mem_size, true, &meta);
+ /* Check access for BPF_WRITE */
+ meta.raw_mode = true;
+ err = err ?: check_helper_mem_access(env, regno, mem_size, true, &meta);
+
+ if (may_be_null)
+ *reg = saved_reg;
+
+ return err;
+}
+
+static int check_kfunc_mem_size_reg(struct bpf_verifier_env *env, struct bpf_reg_state *reg,
+ u32 regno)
+{
+ struct bpf_reg_state *mem_reg = &cur_regs(env)[regno - 1];
+ bool may_be_null = type_may_be_null(mem_reg->type);
+ struct bpf_reg_state saved_reg;
+ struct bpf_call_arg_meta meta;
+ int err;
+
+ WARN_ON_ONCE(regno < BPF_REG_2 || regno > BPF_REG_5);
+
+ memset(&meta, 0, sizeof(meta));
+
+ if (may_be_null) {
+ saved_reg = *mem_reg;
+ mark_ptr_not_null_reg(mem_reg);
+ }
+
+ err = check_mem_size_reg(env, reg, regno, true, &meta);
+ /* Check access for BPF_WRITE */
+ meta.raw_mode = true;
+ err = err ?: check_mem_size_reg(env, reg, regno, true, &meta);
+
+ if (may_be_null)
+ *mem_reg = saved_reg;
+ return err;
+}
+
+/* Implementation details:
+ * bpf_map_lookup returns PTR_TO_MAP_VALUE_OR_NULL.
+ * bpf_obj_new returns PTR_TO_BTF_ID | MEM_ALLOC | PTR_MAYBE_NULL.
+ * Two bpf_map_lookups (even with the same key) will have different reg->id.
+ * Two separate bpf_obj_new will also have different reg->id.
+ * For traditional PTR_TO_MAP_VALUE or PTR_TO_BTF_ID | MEM_ALLOC, the verifier
+ * clears reg->id after value_or_null->value transition, since the verifier only
+ * cares about the range of access to valid map value pointer and doesn't care
+ * about actual address of the map element.
+ * For maps with 'struct bpf_spin_lock' inside map value the verifier keeps
+ * reg->id > 0 after value_or_null->value transition. By doing so
+ * two bpf_map_lookups will be considered two different pointers that
+ * point to different bpf_spin_locks. Likewise for pointers to allocated objects
+ * returned from bpf_obj_new.
+ * The verifier allows taking only one bpf_spin_lock at a time to avoid
+ * dead-locks.
+ * Since only one bpf_spin_lock is allowed the checks are simpler than
+ * reg_is_refcounted() logic. The verifier needs to remember only
+ * one spin_lock instead of array of acquired_refs.
+ * cur_state->active_lock remembers which map value element or allocated
+ * object got locked and clears it after bpf_spin_unlock.
+ */
+static int process_spin_lock(struct bpf_verifier_env *env, int regno,
+ bool is_lock)
+{
+ struct bpf_reg_state *regs = cur_regs(env), *reg = &regs[regno];
+ struct bpf_verifier_state *cur = env->cur_state;
+ bool is_const = tnum_is_const(reg->var_off);
+ u64 val = reg->var_off.value;
+ struct bpf_map *map = NULL;
+ struct btf *btf = NULL;
+ struct btf_record *rec;
+
+ if (!is_const) {
+ verbose(env,
+ "R%d doesn't have constant offset. bpf_spin_lock has to be at the constant offset\n",
+ regno);
+ return -EINVAL;
+ }
+ if (reg->type == PTR_TO_MAP_VALUE) {
+ map = reg->map_ptr;
+ if (!map->btf) {
+ verbose(env,
+ "map '%s' has to have BTF in order to use bpf_spin_lock\n",
+ map->name);
+ return -EINVAL;
+ }
+ } else {
+ btf = reg->btf;
+ }
+
+ rec = reg_btf_record(reg);
+ if (!btf_record_has_field(rec, BPF_SPIN_LOCK)) {
+ verbose(env, "%s '%s' has no valid bpf_spin_lock\n", map ? "map" : "local",
+ map ? map->name : "kptr");
+ return -EINVAL;
+ }
+ if (rec->spin_lock_off != val + reg->off) {
+ verbose(env, "off %lld doesn't point to 'struct bpf_spin_lock' that is at %d\n",
+ val + reg->off, rec->spin_lock_off);
+ return -EINVAL;
+ }
+ if (is_lock) {
+ if (cur->active_lock.ptr) {
+ verbose(env,
+ "Locking two bpf_spin_locks are not allowed\n");
+ return -EINVAL;
+ }
+ if (map)
+ cur->active_lock.ptr = map;
+ else
+ cur->active_lock.ptr = btf;
+ cur->active_lock.id = reg->id;
+ } else {
+ void *ptr;
+
+ if (map)
+ ptr = map;
+ else
+ ptr = btf;
+
+ if (!cur->active_lock.ptr) {
+ verbose(env, "bpf_spin_unlock without taking a lock\n");
+ return -EINVAL;
+ }
+ if (cur->active_lock.ptr != ptr ||
+ cur->active_lock.id != reg->id) {
+ verbose(env, "bpf_spin_unlock of different lock\n");
+ return -EINVAL;
+ }
+
+ invalidate_non_owning_refs(env);
+
+ cur->active_lock.ptr = NULL;
+ cur->active_lock.id = 0;
+ }
+ return 0;
+}
+
+static int process_timer_func(struct bpf_verifier_env *env, int regno,
+ struct bpf_call_arg_meta *meta)
+{
+ struct bpf_reg_state *regs = cur_regs(env), *reg = &regs[regno];
+ bool is_const = tnum_is_const(reg->var_off);
+ struct bpf_map *map = reg->map_ptr;
+ u64 val = reg->var_off.value;
+
+ if (!is_const) {
+ verbose(env,
+ "R%d doesn't have constant offset. bpf_timer has to be at the constant offset\n",
+ regno);
+ return -EINVAL;
+ }
+ if (!map->btf) {
+ verbose(env, "map '%s' has to have BTF in order to use bpf_timer\n",
+ map->name);
+ return -EINVAL;
+ }
+ if (!btf_record_has_field(map->record, BPF_TIMER)) {
+ verbose(env, "map '%s' has no valid bpf_timer\n", map->name);
+ return -EINVAL;
+ }
+ if (map->record->timer_off != val + reg->off) {
+ verbose(env, "off %lld doesn't point to 'struct bpf_timer' that is at %d\n",
+ val + reg->off, map->record->timer_off);
+ return -EINVAL;
+ }
+ if (meta->map_ptr) {
+ verbose(env, "verifier bug. Two map pointers in a timer helper\n");
+ return -EFAULT;
+ }
+ meta->map_uid = reg->map_uid;
+ meta->map_ptr = map;
+ return 0;
+}
+
+static int process_kptr_func(struct bpf_verifier_env *env, int regno,
+ struct bpf_call_arg_meta *meta)
+{
+ struct bpf_reg_state *regs = cur_regs(env), *reg = &regs[regno];
+ struct bpf_map *map_ptr = reg->map_ptr;
+ struct btf_field *kptr_field;
+ u32 kptr_off;
+
+ if (!tnum_is_const(reg->var_off)) {
+ verbose(env,
+ "R%d doesn't have constant offset. kptr has to be at the constant offset\n",
+ regno);
+ return -EINVAL;
+ }
+ if (!map_ptr->btf) {
+ verbose(env, "map '%s' has to have BTF in order to use bpf_kptr_xchg\n",
+ map_ptr->name);
+ return -EINVAL;
+ }
+ if (!btf_record_has_field(map_ptr->record, BPF_KPTR)) {
+ verbose(env, "map '%s' has no valid kptr\n", map_ptr->name);
+ return -EINVAL;
+ }
+
+ meta->map_ptr = map_ptr;
+ kptr_off = reg->off + reg->var_off.value;
+ kptr_field = btf_record_find(map_ptr->record, kptr_off, BPF_KPTR);
+ if (!kptr_field) {
+ verbose(env, "off=%d doesn't point to kptr\n", kptr_off);
+ return -EACCES;
+ }
+ if (kptr_field->type != BPF_KPTR_REF) {
+ verbose(env, "off=%d kptr isn't referenced kptr\n", kptr_off);
+ return -EACCES;
+ }
+ meta->kptr_field = kptr_field;
+ return 0;
+}
+
+/* There are two register types representing a bpf_dynptr, one is PTR_TO_STACK
+ * which points to a stack slot, and the other is CONST_PTR_TO_DYNPTR.
+ *
+ * In both cases we deal with the first 8 bytes, but need to mark the next 8
+ * bytes as STACK_DYNPTR in case of PTR_TO_STACK. In case of
+ * CONST_PTR_TO_DYNPTR, we are guaranteed to get the beginning of the object.
+ *
+ * Mutability of bpf_dynptr is at two levels, one is at the level of struct
+ * bpf_dynptr itself, i.e. whether the helper is receiving a pointer to struct
+ * bpf_dynptr or pointer to const struct bpf_dynptr. In the former case, it can
+ * mutate the view of the dynptr and also possibly destroy it. In the latter
+ * case, it cannot mutate the bpf_dynptr itself but it can still mutate the
+ * memory that dynptr points to.
+ *
+ * The verifier will keep track both levels of mutation (bpf_dynptr's in
+ * reg->type and the memory's in reg->dynptr.type), but there is no support for
+ * readonly dynptr view yet, hence only the first case is tracked and checked.
+ *
+ * This is consistent with how C applies the const modifier to a struct object,
+ * where the pointer itself inside bpf_dynptr becomes const but not what it
+ * points to.
+ *
+ * Helpers which do not mutate the bpf_dynptr set MEM_RDONLY in their argument
+ * type, and declare it as 'const struct bpf_dynptr *' in their prototype.
+ */
+static int process_dynptr_func(struct bpf_verifier_env *env, int regno, int insn_idx,
+ enum bpf_arg_type arg_type, int clone_ref_obj_id)
+{
+ struct bpf_reg_state *regs = cur_regs(env), *reg = &regs[regno];
+ int err;
+
+ /* MEM_UNINIT and MEM_RDONLY are exclusive, when applied to an
+ * ARG_PTR_TO_DYNPTR (or ARG_PTR_TO_DYNPTR | DYNPTR_TYPE_*):
+ */
+ if ((arg_type & (MEM_UNINIT | MEM_RDONLY)) == (MEM_UNINIT | MEM_RDONLY)) {
+ verbose(env, "verifier internal error: misconfigured dynptr helper type flags\n");
+ return -EFAULT;
+ }
+
+ /* MEM_UNINIT - Points to memory that is an appropriate candidate for
+ * constructing a mutable bpf_dynptr object.
+ *
+ * Currently, this is only possible with PTR_TO_STACK
+ * pointing to a region of at least 16 bytes which doesn't
+ * contain an existing bpf_dynptr.
+ *
+ * MEM_RDONLY - Points to a initialized bpf_dynptr that will not be
+ * mutated or destroyed. However, the memory it points to
+ * may be mutated.
+ *
+ * None - Points to a initialized dynptr that can be mutated and
+ * destroyed, including mutation of the memory it points
+ * to.
+ */
+ if (arg_type & MEM_UNINIT) {
+ int i;
+
+ if (!is_dynptr_reg_valid_uninit(env, reg)) {
+ verbose(env, "Dynptr has to be an uninitialized dynptr\n");
+ return -EINVAL;
+ }
+
+ /* we write BPF_DW bits (8 bytes) at a time */
+ for (i = 0; i < BPF_DYNPTR_SIZE; i += 8) {
+ err = check_mem_access(env, insn_idx, regno,
+ i, BPF_DW, BPF_WRITE, -1, false, false);
+ if (err)
+ return err;
+ }
+
+ err = mark_stack_slots_dynptr(env, reg, arg_type, insn_idx, clone_ref_obj_id);
+ } else /* MEM_RDONLY and None case from above */ {
+ /* For the reg->type == PTR_TO_STACK case, bpf_dynptr is never const */
+ if (reg->type == CONST_PTR_TO_DYNPTR && !(arg_type & MEM_RDONLY)) {
+ verbose(env, "cannot pass pointer to const bpf_dynptr, the helper mutates it\n");
+ return -EINVAL;
+ }
+
+ if (!is_dynptr_reg_valid_init(env, reg)) {
+ verbose(env,
+ "Expected an initialized dynptr as arg #%d\n",
+ regno);
+ return -EINVAL;
+ }
+
+ /* Fold modifiers (in this case, MEM_RDONLY) when checking expected type */
+ if (!is_dynptr_type_expected(env, reg, arg_type & ~MEM_RDONLY)) {
+ verbose(env,
+ "Expected a dynptr of type %s as arg #%d\n",
+ dynptr_type_str(arg_to_dynptr_type(arg_type)), regno);
+ return -EINVAL;
+ }
+
+ err = mark_dynptr_read(env, reg);
+ }
+ return err;
+}
+
+static u32 iter_ref_obj_id(struct bpf_verifier_env *env, struct bpf_reg_state *reg, int spi)
+{
+ struct bpf_func_state *state = func(env, reg);
+
+ return state->stack[spi].spilled_ptr.ref_obj_id;
+}
+
+static bool is_iter_kfunc(struct bpf_kfunc_call_arg_meta *meta)
+{
+ return meta->kfunc_flags & (KF_ITER_NEW | KF_ITER_NEXT | KF_ITER_DESTROY);
+}
+
+static bool is_iter_new_kfunc(struct bpf_kfunc_call_arg_meta *meta)
+{
+ return meta->kfunc_flags & KF_ITER_NEW;
+}
+
+static bool is_iter_next_kfunc(struct bpf_kfunc_call_arg_meta *meta)
+{
+ return meta->kfunc_flags & KF_ITER_NEXT;
+}
+
+static bool is_iter_destroy_kfunc(struct bpf_kfunc_call_arg_meta *meta)
+{
+ return meta->kfunc_flags & KF_ITER_DESTROY;
+}
+
+static bool is_kfunc_arg_iter(struct bpf_kfunc_call_arg_meta *meta, int arg)
+{
+ /* btf_check_iter_kfuncs() guarantees that first argument of any iter
+ * kfunc is iter state pointer
+ */
+ return arg == 0 && is_iter_kfunc(meta);
+}
+
+static int process_iter_arg(struct bpf_verifier_env *env, int regno, int insn_idx,
+ struct bpf_kfunc_call_arg_meta *meta)
+{
+ struct bpf_reg_state *regs = cur_regs(env), *reg = &regs[regno];
+ const struct btf_type *t;
+ const struct btf_param *arg;
+ int spi, err, i, nr_slots;
+ u32 btf_id;
+
+ /* btf_check_iter_kfuncs() ensures we don't need to validate anything here */
+ arg = &btf_params(meta->func_proto)[0];
+ t = btf_type_skip_modifiers(meta->btf, arg->type, NULL); /* PTR */
+ t = btf_type_skip_modifiers(meta->btf, t->type, &btf_id); /* STRUCT */
+ nr_slots = t->size / BPF_REG_SIZE;
+
+ if (is_iter_new_kfunc(meta)) {
+ /* bpf_iter_<type>_new() expects pointer to uninit iter state */
+ if (!is_iter_reg_valid_uninit(env, reg, nr_slots)) {
+ verbose(env, "expected uninitialized iter_%s as arg #%d\n",
+ iter_type_str(meta->btf, btf_id), regno);
+ return -EINVAL;
+ }
+
+ for (i = 0; i < nr_slots * 8; i += BPF_REG_SIZE) {
+ err = check_mem_access(env, insn_idx, regno,
+ i, BPF_DW, BPF_WRITE, -1, false, false);
+ if (err)
+ return err;
+ }
+
+ err = mark_stack_slots_iter(env, reg, insn_idx, meta->btf, btf_id, nr_slots);
+ if (err)
+ return err;
+ } else {
+ /* iter_next() or iter_destroy() expect initialized iter state*/
+ if (!is_iter_reg_valid_init(env, reg, meta->btf, btf_id, nr_slots)) {
+ verbose(env, "expected an initialized iter_%s as arg #%d\n",
+ iter_type_str(meta->btf, btf_id), regno);
+ return -EINVAL;
+ }
+
+ spi = iter_get_spi(env, reg, nr_slots);
+ if (spi < 0)
+ return spi;
+
+ err = mark_iter_read(env, reg, spi, nr_slots);
+ if (err)
+ return err;
+
+ /* remember meta->iter info for process_iter_next_call() */
+ meta->iter.spi = spi;
+ meta->iter.frameno = reg->frameno;
+ meta->ref_obj_id = iter_ref_obj_id(env, reg, spi);
+
+ if (is_iter_destroy_kfunc(meta)) {
+ err = unmark_stack_slots_iter(env, reg, nr_slots);
+ if (err)
+ return err;
+ }
+ }
+
+ return 0;
+}
+
+/* Look for a previous loop entry at insn_idx: nearest parent state
+ * stopped at insn_idx with callsites matching those in cur->frame.
+ */
+static struct bpf_verifier_state *find_prev_entry(struct bpf_verifier_env *env,
+ struct bpf_verifier_state *cur,
+ int insn_idx)
+{
+ struct bpf_verifier_state_list *sl;
+ struct bpf_verifier_state *st;
+
+ /* Explored states are pushed in stack order, most recent states come first */
+ sl = *explored_state(env, insn_idx);
+ for (; sl; sl = sl->next) {
+ /* If st->branches != 0 state is a part of current DFS verification path,
+ * hence cur & st for a loop.
+ */
+ st = &sl->state;
+ if (st->insn_idx == insn_idx && st->branches && same_callsites(st, cur) &&
+ st->dfs_depth < cur->dfs_depth)
+ return st;
+ }
+
+ return NULL;
+}
+
+static void reset_idmap_scratch(struct bpf_verifier_env *env);
+static bool regs_exact(const struct bpf_reg_state *rold,
+ const struct bpf_reg_state *rcur,
+ struct bpf_idmap *idmap);
+
+static void maybe_widen_reg(struct bpf_verifier_env *env,
+ struct bpf_reg_state *rold, struct bpf_reg_state *rcur,
+ struct bpf_idmap *idmap)
+{
+ if (rold->type != SCALAR_VALUE)
+ return;
+ if (rold->type != rcur->type)
+ return;
+ if (rold->precise || rcur->precise || regs_exact(rold, rcur, idmap))
+ return;
+ __mark_reg_unknown(env, rcur);
+}
+
+static int widen_imprecise_scalars(struct bpf_verifier_env *env,
+ struct bpf_verifier_state *old,
+ struct bpf_verifier_state *cur)
+{
+ struct bpf_func_state *fold, *fcur;
+ int i, fr;
+
+ reset_idmap_scratch(env);
+ for (fr = old->curframe; fr >= 0; fr--) {
+ fold = old->frame[fr];
+ fcur = cur->frame[fr];
+
+ for (i = 0; i < MAX_BPF_REG; i++)
+ maybe_widen_reg(env,
+ &fold->regs[i],
+ &fcur->regs[i],
+ &env->idmap_scratch);
+
+ for (i = 0; i < fold->allocated_stack / BPF_REG_SIZE; i++) {
+ if (!is_spilled_reg(&fold->stack[i]) ||
+ !is_spilled_reg(&fcur->stack[i]))
+ continue;
+
+ maybe_widen_reg(env,
+ &fold->stack[i].spilled_ptr,
+ &fcur->stack[i].spilled_ptr,
+ &env->idmap_scratch);
+ }
+ }
+ return 0;
+}
+
+/* process_iter_next_call() is called when verifier gets to iterator's next
+ * "method" (e.g., bpf_iter_num_next() for numbers iterator) call. We'll refer
+ * to it as just "iter_next()" in comments below.
+ *
+ * BPF verifier relies on a crucial contract for any iter_next()
+ * implementation: it should *eventually* return NULL, and once that happens
+ * it should keep returning NULL. That is, once iterator exhausts elements to
+ * iterate, it should never reset or spuriously return new elements.
+ *
+ * With the assumption of such contract, process_iter_next_call() simulates
+ * a fork in the verifier state to validate loop logic correctness and safety
+ * without having to simulate infinite amount of iterations.
+ *
+ * In current state, we first assume that iter_next() returned NULL and
+ * iterator state is set to DRAINED (BPF_ITER_STATE_DRAINED). In such
+ * conditions we should not form an infinite loop and should eventually reach
+ * exit.
+ *
+ * Besides that, we also fork current state and enqueue it for later
+ * verification. In a forked state we keep iterator state as ACTIVE
+ * (BPF_ITER_STATE_ACTIVE) and assume non-NULL return from iter_next(). We
+ * also bump iteration depth to prevent erroneous infinite loop detection
+ * later on (see iter_active_depths_differ() comment for details). In this
+ * state we assume that we'll eventually loop back to another iter_next()
+ * calls (it could be in exactly same location or in some other instruction,
+ * it doesn't matter, we don't make any unnecessary assumptions about this,
+ * everything revolves around iterator state in a stack slot, not which
+ * instruction is calling iter_next()). When that happens, we either will come
+ * to iter_next() with equivalent state and can conclude that next iteration
+ * will proceed in exactly the same way as we just verified, so it's safe to
+ * assume that loop converges. If not, we'll go on another iteration
+ * simulation with a different input state, until all possible starting states
+ * are validated or we reach maximum number of instructions limit.
+ *
+ * This way, we will either exhaustively discover all possible input states
+ * that iterator loop can start with and eventually will converge, or we'll
+ * effectively regress into bounded loop simulation logic and either reach
+ * maximum number of instructions if loop is not provably convergent, or there
+ * is some statically known limit on number of iterations (e.g., if there is
+ * an explicit `if n > 100 then break;` statement somewhere in the loop).
+ *
+ * Iteration convergence logic in is_state_visited() relies on exact
+ * states comparison, which ignores read and precision marks.
+ * This is necessary because read and precision marks are not finalized
+ * while in the loop. Exact comparison might preclude convergence for
+ * simple programs like below:
+ *
+ * i = 0;
+ * while(iter_next(&it))
+ * i++;
+ *
+ * At each iteration step i++ would produce a new distinct state and
+ * eventually instruction processing limit would be reached.
+ *
+ * To avoid such behavior speculatively forget (widen) range for
+ * imprecise scalar registers, if those registers were not precise at the
+ * end of the previous iteration and do not match exactly.
+ *
+ * This is a conservative heuristic that allows to verify wide range of programs,
+ * however it precludes verification of programs that conjure an
+ * imprecise value on the first loop iteration and use it as precise on a second.
+ * For example, the following safe program would fail to verify:
+ *
+ * struct bpf_num_iter it;
+ * int arr[10];
+ * int i = 0, a = 0;
+ * bpf_iter_num_new(&it, 0, 10);
+ * while (bpf_iter_num_next(&it)) {
+ * if (a == 0) {
+ * a = 1;
+ * i = 7; // Because i changed verifier would forget
+ * // it's range on second loop entry.
+ * } else {
+ * arr[i] = 42; // This would fail to verify.
+ * }
+ * }
+ * bpf_iter_num_destroy(&it);
+ */
+static int process_iter_next_call(struct bpf_verifier_env *env, int insn_idx,
+ struct bpf_kfunc_call_arg_meta *meta)
+{
+ struct bpf_verifier_state *cur_st = env->cur_state, *queued_st, *prev_st;
+ struct bpf_func_state *cur_fr = cur_st->frame[cur_st->curframe], *queued_fr;
+ struct bpf_reg_state *cur_iter, *queued_iter;
+ int iter_frameno = meta->iter.frameno;
+ int iter_spi = meta->iter.spi;
+
+ BTF_TYPE_EMIT(struct bpf_iter);
+
+ cur_iter = &env->cur_state->frame[iter_frameno]->stack[iter_spi].spilled_ptr;
+
+ if (cur_iter->iter.state != BPF_ITER_STATE_ACTIVE &&
+ cur_iter->iter.state != BPF_ITER_STATE_DRAINED) {
+ verbose(env, "verifier internal error: unexpected iterator state %d (%s)\n",
+ cur_iter->iter.state, iter_state_str(cur_iter->iter.state));
+ return -EFAULT;
+ }
+
+ if (cur_iter->iter.state == BPF_ITER_STATE_ACTIVE) {
+ /* Because iter_next() call is a checkpoint is_state_visitied()
+ * should guarantee parent state with same call sites and insn_idx.
+ */
+ if (!cur_st->parent || cur_st->parent->insn_idx != insn_idx ||
+ !same_callsites(cur_st->parent, cur_st)) {
+ verbose(env, "bug: bad parent state for iter next call");
+ return -EFAULT;
+ }
+ /* Note cur_st->parent in the call below, it is necessary to skip
+ * checkpoint created for cur_st by is_state_visited()
+ * right at this instruction.
+ */
+ prev_st = find_prev_entry(env, cur_st->parent, insn_idx);
+ /* branch out active iter state */
+ queued_st = push_stack(env, insn_idx + 1, insn_idx, false);
+ if (!queued_st)
+ return -ENOMEM;
+
+ queued_iter = &queued_st->frame[iter_frameno]->stack[iter_spi].spilled_ptr;
+ queued_iter->iter.state = BPF_ITER_STATE_ACTIVE;
+ queued_iter->iter.depth++;
+ if (prev_st)
+ widen_imprecise_scalars(env, prev_st, queued_st);
+
+ queued_fr = queued_st->frame[queued_st->curframe];
+ mark_ptr_not_null_reg(&queued_fr->regs[BPF_REG_0]);
+ }
+
+ /* switch to DRAINED state, but keep the depth unchanged */
+ /* mark current iter state as drained and assume returned NULL */
+ cur_iter->iter.state = BPF_ITER_STATE_DRAINED;
+ __mark_reg_const_zero(&cur_fr->regs[BPF_REG_0]);
+
+ return 0;
+}
+
+static bool arg_type_is_mem_size(enum bpf_arg_type type)
+{
+ return type == ARG_CONST_SIZE ||
+ type == ARG_CONST_SIZE_OR_ZERO;
+}
+
+static bool arg_type_is_release(enum bpf_arg_type type)
+{
+ return type & OBJ_RELEASE;
+}
+
+static bool arg_type_is_dynptr(enum bpf_arg_type type)
+{
+ return base_type(type) == ARG_PTR_TO_DYNPTR;
+}
+
+static int int_ptr_type_to_size(enum bpf_arg_type type)
+{
+ if (type == ARG_PTR_TO_INT)
+ return sizeof(u32);
+ else if (type == ARG_PTR_TO_LONG)
+ return sizeof(u64);
+
+ return -EINVAL;
+}
+
+static int resolve_map_arg_type(struct bpf_verifier_env *env,
+ const struct bpf_call_arg_meta *meta,
+ enum bpf_arg_type *arg_type)
+{
+ if (!meta->map_ptr) {
+ /* kernel subsystem misconfigured verifier */
+ verbose(env, "invalid map_ptr to access map->type\n");
+ return -EACCES;
+ }
+
+ switch (meta->map_ptr->map_type) {
+ case BPF_MAP_TYPE_SOCKMAP:
+ case BPF_MAP_TYPE_SOCKHASH:
+ if (*arg_type == ARG_PTR_TO_MAP_VALUE) {
+ *arg_type = ARG_PTR_TO_BTF_ID_SOCK_COMMON;
+ } else {
+ verbose(env, "invalid arg_type for sockmap/sockhash\n");
+ return -EINVAL;
+ }
+ break;
+ case BPF_MAP_TYPE_BLOOM_FILTER:
+ if (meta->func_id == BPF_FUNC_map_peek_elem)
+ *arg_type = ARG_PTR_TO_MAP_VALUE;
+ break;
+ default:
+ break;
+ }
+ return 0;
+}
+
+struct bpf_reg_types {
+ const enum bpf_reg_type types[10];
+ u32 *btf_id;
+};
+
+static const struct bpf_reg_types sock_types = {
+ .types = {
+ PTR_TO_SOCK_COMMON,
+ PTR_TO_SOCKET,
+ PTR_TO_TCP_SOCK,
+ PTR_TO_XDP_SOCK,
+ },
+};
+
+#ifdef CONFIG_NET
+static const struct bpf_reg_types btf_id_sock_common_types = {
+ .types = {
+ PTR_TO_SOCK_COMMON,
+ PTR_TO_SOCKET,
+ PTR_TO_TCP_SOCK,
+ PTR_TO_XDP_SOCK,
+ PTR_TO_BTF_ID,
+ PTR_TO_BTF_ID | PTR_TRUSTED,
+ },
+ .btf_id = &btf_sock_ids[BTF_SOCK_TYPE_SOCK_COMMON],
+};
+#endif
+
+static const struct bpf_reg_types mem_types = {
+ .types = {
+ PTR_TO_STACK,
+ PTR_TO_PACKET,
+ PTR_TO_PACKET_META,
+ PTR_TO_MAP_KEY,
+ PTR_TO_MAP_VALUE,
+ PTR_TO_MEM,
+ PTR_TO_MEM | MEM_RINGBUF,
+ PTR_TO_BUF,
+ PTR_TO_BTF_ID | PTR_TRUSTED,
+ },
+};
+
+static const struct bpf_reg_types int_ptr_types = {
+ .types = {
+ PTR_TO_STACK,
+ PTR_TO_PACKET,
+ PTR_TO_PACKET_META,
+ PTR_TO_MAP_KEY,
+ PTR_TO_MAP_VALUE,
+ },
+};
+
+static const struct bpf_reg_types spin_lock_types = {
+ .types = {
+ PTR_TO_MAP_VALUE,
+ PTR_TO_BTF_ID | MEM_ALLOC,
+ }
+};
+
+static const struct bpf_reg_types fullsock_types = { .types = { PTR_TO_SOCKET } };
+static const struct bpf_reg_types scalar_types = { .types = { SCALAR_VALUE } };
+static const struct bpf_reg_types context_types = { .types = { PTR_TO_CTX } };
+static const struct bpf_reg_types ringbuf_mem_types = { .types = { PTR_TO_MEM | MEM_RINGBUF } };
+static const struct bpf_reg_types const_map_ptr_types = { .types = { CONST_PTR_TO_MAP } };
+static const struct bpf_reg_types btf_ptr_types = {
+ .types = {
+ PTR_TO_BTF_ID,
+ PTR_TO_BTF_ID | PTR_TRUSTED,
+ PTR_TO_BTF_ID | MEM_RCU,
+ },
+};
+static const struct bpf_reg_types percpu_btf_ptr_types = {
+ .types = {
+ PTR_TO_BTF_ID | MEM_PERCPU,
+ PTR_TO_BTF_ID | MEM_PERCPU | PTR_TRUSTED,
+ }
+};
+static const struct bpf_reg_types func_ptr_types = { .types = { PTR_TO_FUNC } };
+static const struct bpf_reg_types stack_ptr_types = { .types = { PTR_TO_STACK } };
+static const struct bpf_reg_types const_str_ptr_types = { .types = { PTR_TO_MAP_VALUE } };
+static const struct bpf_reg_types timer_types = { .types = { PTR_TO_MAP_VALUE } };
+static const struct bpf_reg_types kptr_types = { .types = { PTR_TO_MAP_VALUE } };
+static const struct bpf_reg_types dynptr_types = {
+ .types = {
+ PTR_TO_STACK,
+ CONST_PTR_TO_DYNPTR,
+ }
+};
+
+static const struct bpf_reg_types *compatible_reg_types[__BPF_ARG_TYPE_MAX] = {
+ [ARG_PTR_TO_MAP_KEY] = &mem_types,
+ [ARG_PTR_TO_MAP_VALUE] = &mem_types,
+ [ARG_CONST_SIZE] = &scalar_types,
+ [ARG_CONST_SIZE_OR_ZERO] = &scalar_types,
+ [ARG_CONST_ALLOC_SIZE_OR_ZERO] = &scalar_types,
+ [ARG_CONST_MAP_PTR] = &const_map_ptr_types,
+ [ARG_PTR_TO_CTX] = &context_types,
+ [ARG_PTR_TO_SOCK_COMMON] = &sock_types,
+#ifdef CONFIG_NET
+ [ARG_PTR_TO_BTF_ID_SOCK_COMMON] = &btf_id_sock_common_types,
+#endif
+ [ARG_PTR_TO_SOCKET] = &fullsock_types,
+ [ARG_PTR_TO_BTF_ID] = &btf_ptr_types,
+ [ARG_PTR_TO_SPIN_LOCK] = &spin_lock_types,
+ [ARG_PTR_TO_MEM] = &mem_types,
+ [ARG_PTR_TO_RINGBUF_MEM] = &ringbuf_mem_types,
+ [ARG_PTR_TO_INT] = &int_ptr_types,
+ [ARG_PTR_TO_LONG] = &int_ptr_types,
+ [ARG_PTR_TO_PERCPU_BTF_ID] = &percpu_btf_ptr_types,
+ [ARG_PTR_TO_FUNC] = &func_ptr_types,
+ [ARG_PTR_TO_STACK] = &stack_ptr_types,
+ [ARG_PTR_TO_CONST_STR] = &const_str_ptr_types,
+ [ARG_PTR_TO_TIMER] = &timer_types,
+ [ARG_PTR_TO_KPTR] = &kptr_types,
+ [ARG_PTR_TO_DYNPTR] = &dynptr_types,
+};
+
+static int check_reg_type(struct bpf_verifier_env *env, u32 regno,
+ enum bpf_arg_type arg_type,
+ const u32 *arg_btf_id,
+ struct bpf_call_arg_meta *meta)
+{
+ struct bpf_reg_state *regs = cur_regs(env), *reg = &regs[regno];
+ enum bpf_reg_type expected, type = reg->type;
+ const struct bpf_reg_types *compatible;
+ int i, j;
+
+ compatible = compatible_reg_types[base_type(arg_type)];
+ if (!compatible) {
+ verbose(env, "verifier internal error: unsupported arg type %d\n", arg_type);
+ return -EFAULT;
+ }
+
+ /* ARG_PTR_TO_MEM + RDONLY is compatible with PTR_TO_MEM and PTR_TO_MEM + RDONLY,
+ * but ARG_PTR_TO_MEM is compatible only with PTR_TO_MEM and NOT with PTR_TO_MEM + RDONLY
+ *
+ * Same for MAYBE_NULL:
+ *
+ * ARG_PTR_TO_MEM + MAYBE_NULL is compatible with PTR_TO_MEM and PTR_TO_MEM + MAYBE_NULL,
+ * but ARG_PTR_TO_MEM is compatible only with PTR_TO_MEM but NOT with PTR_TO_MEM + MAYBE_NULL
+ *
+ * ARG_PTR_TO_MEM is compatible with PTR_TO_MEM that is tagged with a dynptr type.
+ *
+ * Therefore we fold these flags depending on the arg_type before comparison.
+ */
+ if (arg_type & MEM_RDONLY)
+ type &= ~MEM_RDONLY;
+ if (arg_type & PTR_MAYBE_NULL)
+ type &= ~PTR_MAYBE_NULL;
+ if (base_type(arg_type) == ARG_PTR_TO_MEM)
+ type &= ~DYNPTR_TYPE_FLAG_MASK;
+
+ if (meta->func_id == BPF_FUNC_kptr_xchg && type_is_alloc(type))
+ type &= ~MEM_ALLOC;
+
+ for (i = 0; i < ARRAY_SIZE(compatible->types); i++) {
+ expected = compatible->types[i];
+ if (expected == NOT_INIT)
+ break;
+
+ if (type == expected)
+ goto found;
+ }
+
+ verbose(env, "R%d type=%s expected=", regno, reg_type_str(env, reg->type));
+ for (j = 0; j + 1 < i; j++)
+ verbose(env, "%s, ", reg_type_str(env, compatible->types[j]));
+ verbose(env, "%s\n", reg_type_str(env, compatible->types[j]));
+ return -EACCES;
+
+found:
+ if (base_type(reg->type) != PTR_TO_BTF_ID)
+ return 0;
+
+ if (compatible == &mem_types) {
+ if (!(arg_type & MEM_RDONLY)) {
+ verbose(env,
+ "%s() may write into memory pointed by R%d type=%s\n",
+ func_id_name(meta->func_id),
+ regno, reg_type_str(env, reg->type));
+ return -EACCES;
+ }
+ return 0;
+ }
+
+ switch ((int)reg->type) {
+ case PTR_TO_BTF_ID:
+ case PTR_TO_BTF_ID | PTR_TRUSTED:
+ case PTR_TO_BTF_ID | MEM_RCU:
+ case PTR_TO_BTF_ID | PTR_MAYBE_NULL:
+ case PTR_TO_BTF_ID | PTR_MAYBE_NULL | MEM_RCU:
+ {
+ /* For bpf_sk_release, it needs to match against first member
+ * 'struct sock_common', hence make an exception for it. This
+ * allows bpf_sk_release to work for multiple socket types.
+ */
+ bool strict_type_match = arg_type_is_release(arg_type) &&
+ meta->func_id != BPF_FUNC_sk_release;
+
+ if (type_may_be_null(reg->type) &&
+ (!type_may_be_null(arg_type) || arg_type_is_release(arg_type))) {
+ verbose(env, "Possibly NULL pointer passed to helper arg%d\n", regno);
+ return -EACCES;
+ }
+
+ if (!arg_btf_id) {
+ if (!compatible->btf_id) {
+ verbose(env, "verifier internal error: missing arg compatible BTF ID\n");
+ return -EFAULT;
+ }
+ arg_btf_id = compatible->btf_id;
+ }
+
+ if (meta->func_id == BPF_FUNC_kptr_xchg) {
+ if (map_kptr_match_type(env, meta->kptr_field, reg, regno))
+ return -EACCES;
+ } else {
+ if (arg_btf_id == BPF_PTR_POISON) {
+ verbose(env, "verifier internal error:");
+ verbose(env, "R%d has non-overwritten BPF_PTR_POISON type\n",
+ regno);
+ return -EACCES;
+ }
+
+ if (!btf_struct_ids_match(&env->log, reg->btf, reg->btf_id, reg->off,
+ btf_vmlinux, *arg_btf_id,
+ strict_type_match)) {
+ verbose(env, "R%d is of type %s but %s is expected\n",
+ regno, btf_type_name(reg->btf, reg->btf_id),
+ btf_type_name(btf_vmlinux, *arg_btf_id));
+ return -EACCES;
+ }
+ }
+ break;
+ }
+ case PTR_TO_BTF_ID | MEM_ALLOC:
+ if (meta->func_id != BPF_FUNC_spin_lock && meta->func_id != BPF_FUNC_spin_unlock &&
+ meta->func_id != BPF_FUNC_kptr_xchg) {
+ verbose(env, "verifier internal error: unimplemented handling of MEM_ALLOC\n");
+ return -EFAULT;
+ }
+ if (meta->func_id == BPF_FUNC_kptr_xchg) {
+ if (map_kptr_match_type(env, meta->kptr_field, reg, regno))
+ return -EACCES;
+ }
+ break;
+ case PTR_TO_BTF_ID | MEM_PERCPU:
+ case PTR_TO_BTF_ID | MEM_PERCPU | PTR_TRUSTED:
+ /* Handled by helper specific checks */
+ break;
+ default:
+ verbose(env, "verifier internal error: invalid PTR_TO_BTF_ID register for type match\n");
+ return -EFAULT;
+ }
+ return 0;
+}
+
+static struct btf_field *
+reg_find_field_offset(const struct bpf_reg_state *reg, s32 off, u32 fields)
+{
+ struct btf_field *field;
+ struct btf_record *rec;
+
+ rec = reg_btf_record(reg);
+ if (!rec)
+ return NULL;
+
+ field = btf_record_find(rec, off, fields);
+ if (!field)
+ return NULL;
+
+ return field;
+}
+
+int check_func_arg_reg_off(struct bpf_verifier_env *env,
+ const struct bpf_reg_state *reg, int regno,
+ enum bpf_arg_type arg_type)
+{
+ u32 type = reg->type;
+
+ /* When referenced register is passed to release function, its fixed
+ * offset must be 0.
+ *
+ * We will check arg_type_is_release reg has ref_obj_id when storing
+ * meta->release_regno.
+ */
+ if (arg_type_is_release(arg_type)) {
+ /* ARG_PTR_TO_DYNPTR with OBJ_RELEASE is a bit special, as it
+ * may not directly point to the object being released, but to
+ * dynptr pointing to such object, which might be at some offset
+ * on the stack. In that case, we simply to fallback to the
+ * default handling.
+ */
+ if (arg_type_is_dynptr(arg_type) && type == PTR_TO_STACK)
+ return 0;
+
+ /* Doing check_ptr_off_reg check for the offset will catch this
+ * because fixed_off_ok is false, but checking here allows us
+ * to give the user a better error message.
+ */
+ if (reg->off) {
+ verbose(env, "R%d must have zero offset when passed to release func or trusted arg to kfunc\n",
+ regno);
+ return -EINVAL;
+ }
+ return __check_ptr_off_reg(env, reg, regno, false);
+ }
+
+ switch (type) {
+ /* Pointer types where both fixed and variable offset is explicitly allowed: */
+ case PTR_TO_STACK:
+ case PTR_TO_PACKET:
+ case PTR_TO_PACKET_META:
+ case PTR_TO_MAP_KEY:
+ case PTR_TO_MAP_VALUE:
+ case PTR_TO_MEM:
+ case PTR_TO_MEM | MEM_RDONLY:
+ case PTR_TO_MEM | MEM_RINGBUF:
+ case PTR_TO_BUF:
+ case PTR_TO_BUF | MEM_RDONLY:
+ case SCALAR_VALUE:
+ return 0;
+ /* All the rest must be rejected, except PTR_TO_BTF_ID which allows
+ * fixed offset.
+ */
+ case PTR_TO_BTF_ID:
+ case PTR_TO_BTF_ID | MEM_ALLOC:
+ case PTR_TO_BTF_ID | PTR_TRUSTED:
+ case PTR_TO_BTF_ID | MEM_RCU:
+ case PTR_TO_BTF_ID | MEM_ALLOC | NON_OWN_REF:
+ case PTR_TO_BTF_ID | MEM_ALLOC | NON_OWN_REF | MEM_RCU:
+ /* When referenced PTR_TO_BTF_ID is passed to release function,
+ * its fixed offset must be 0. In the other cases, fixed offset
+ * can be non-zero. This was already checked above. So pass
+ * fixed_off_ok as true to allow fixed offset for all other
+ * cases. var_off always must be 0 for PTR_TO_BTF_ID, hence we
+ * still need to do checks instead of returning.
+ */
+ return __check_ptr_off_reg(env, reg, regno, true);
+ default:
+ return __check_ptr_off_reg(env, reg, regno, false);
+ }
+}
+
+static struct bpf_reg_state *get_dynptr_arg_reg(struct bpf_verifier_env *env,
+ const struct bpf_func_proto *fn,
+ struct bpf_reg_state *regs)
+{
+ struct bpf_reg_state *state = NULL;
+ int i;
+
+ for (i = 0; i < MAX_BPF_FUNC_REG_ARGS; i++)
+ if (arg_type_is_dynptr(fn->arg_type[i])) {
+ if (state) {
+ verbose(env, "verifier internal error: multiple dynptr args\n");
+ return NULL;
+ }
+ state = &regs[BPF_REG_1 + i];
+ }
+
+ if (!state)
+ verbose(env, "verifier internal error: no dynptr arg found\n");
+
+ return state;
+}
+
+static int dynptr_id(struct bpf_verifier_env *env, struct bpf_reg_state *reg)
+{
+ struct bpf_func_state *state = func(env, reg);
+ int spi;
+
+ if (reg->type == CONST_PTR_TO_DYNPTR)
+ return reg->id;
+ spi = dynptr_get_spi(env, reg);
+ if (spi < 0)
+ return spi;
+ return state->stack[spi].spilled_ptr.id;
+}
+
+static int dynptr_ref_obj_id(struct bpf_verifier_env *env, struct bpf_reg_state *reg)
+{
+ struct bpf_func_state *state = func(env, reg);
+ int spi;
+
+ if (reg->type == CONST_PTR_TO_DYNPTR)
+ return reg->ref_obj_id;
+ spi = dynptr_get_spi(env, reg);
+ if (spi < 0)
+ return spi;
+ return state->stack[spi].spilled_ptr.ref_obj_id;
+}
+
+static enum bpf_dynptr_type dynptr_get_type(struct bpf_verifier_env *env,
+ struct bpf_reg_state *reg)
+{
+ struct bpf_func_state *state = func(env, reg);
+ int spi;
+
+ if (reg->type == CONST_PTR_TO_DYNPTR)
+ return reg->dynptr.type;
+
+ spi = __get_spi(reg->off);
+ if (spi < 0) {
+ verbose(env, "verifier internal error: invalid spi when querying dynptr type\n");
+ return BPF_DYNPTR_TYPE_INVALID;
+ }
+
+ return state->stack[spi].spilled_ptr.dynptr.type;
+}
+
+static int check_func_arg(struct bpf_verifier_env *env, u32 arg,
+ struct bpf_call_arg_meta *meta,
+ const struct bpf_func_proto *fn,
+ int insn_idx)
+{
+ u32 regno = BPF_REG_1 + arg;
+ struct bpf_reg_state *regs = cur_regs(env), *reg = &regs[regno];
+ enum bpf_arg_type arg_type = fn->arg_type[arg];
+ enum bpf_reg_type type = reg->type;
+ u32 *arg_btf_id = NULL;
+ int err = 0;
+
+ if (arg_type == ARG_DONTCARE)
+ return 0;
+
+ err = check_reg_arg(env, regno, SRC_OP);
+ if (err)
+ return err;
+
+ if (arg_type == ARG_ANYTHING) {
+ if (is_pointer_value(env, regno)) {
+ verbose(env, "R%d leaks addr into helper function\n",
+ regno);
+ return -EACCES;
+ }
+ return 0;
+ }
+
+ if (type_is_pkt_pointer(type) &&
+ !may_access_direct_pkt_data(env, meta, BPF_READ)) {
+ verbose(env, "helper access to the packet is not allowed\n");
+ return -EACCES;
+ }
+
+ if (base_type(arg_type) == ARG_PTR_TO_MAP_VALUE) {
+ err = resolve_map_arg_type(env, meta, &arg_type);
+ if (err)
+ return err;
+ }
+
+ if (register_is_null(reg) && type_may_be_null(arg_type))
+ /* A NULL register has a SCALAR_VALUE type, so skip
+ * type checking.
+ */
+ goto skip_type_check;
+
+ /* arg_btf_id and arg_size are in a union. */
+ if (base_type(arg_type) == ARG_PTR_TO_BTF_ID ||
+ base_type(arg_type) == ARG_PTR_TO_SPIN_LOCK)
+ arg_btf_id = fn->arg_btf_id[arg];
+
+ err = check_reg_type(env, regno, arg_type, arg_btf_id, meta);
+ if (err)
+ return err;
+
+ err = check_func_arg_reg_off(env, reg, regno, arg_type);
+ if (err)
+ return err;
+
+skip_type_check:
+ if (arg_type_is_release(arg_type)) {
+ if (arg_type_is_dynptr(arg_type)) {
+ struct bpf_func_state *state = func(env, reg);
+ int spi;
+
+ /* Only dynptr created on stack can be released, thus
+ * the get_spi and stack state checks for spilled_ptr
+ * should only be done before process_dynptr_func for
+ * PTR_TO_STACK.
+ */
+ if (reg->type == PTR_TO_STACK) {
+ spi = dynptr_get_spi(env, reg);
+ if (spi < 0 || !state->stack[spi].spilled_ptr.ref_obj_id) {
+ verbose(env, "arg %d is an unacquired reference\n", regno);
+ return -EINVAL;
+ }
+ } else {
+ verbose(env, "cannot release unowned const bpf_dynptr\n");
+ return -EINVAL;
+ }
+ } else if (!reg->ref_obj_id && !register_is_null(reg)) {
+ verbose(env, "R%d must be referenced when passed to release function\n",
+ regno);
+ return -EINVAL;
+ }
+ if (meta->release_regno) {
+ verbose(env, "verifier internal error: more than one release argument\n");
+ return -EFAULT;
+ }
+ meta->release_regno = regno;
+ }
+
+ if (reg->ref_obj_id) {
+ if (meta->ref_obj_id) {
+ verbose(env, "verifier internal error: more than one arg with ref_obj_id R%d %u %u\n",
+ regno, reg->ref_obj_id,
+ meta->ref_obj_id);
+ return -EFAULT;
+ }
+ meta->ref_obj_id = reg->ref_obj_id;
+ }
+
+ switch (base_type(arg_type)) {
+ case ARG_CONST_MAP_PTR:
+ /* bpf_map_xxx(map_ptr) call: remember that map_ptr */
+ if (meta->map_ptr) {
+ /* Use map_uid (which is unique id of inner map) to reject:
+ * inner_map1 = bpf_map_lookup_elem(outer_map, key1)
+ * inner_map2 = bpf_map_lookup_elem(outer_map, key2)
+ * if (inner_map1 && inner_map2) {
+ * timer = bpf_map_lookup_elem(inner_map1);
+ * if (timer)
+ * // mismatch would have been allowed
+ * bpf_timer_init(timer, inner_map2);
+ * }
+ *
+ * Comparing map_ptr is enough to distinguish normal and outer maps.
+ */
+ if (meta->map_ptr != reg->map_ptr ||
+ meta->map_uid != reg->map_uid) {
+ verbose(env,
+ "timer pointer in R1 map_uid=%d doesn't match map pointer in R2 map_uid=%d\n",
+ meta->map_uid, reg->map_uid);
+ return -EINVAL;
+ }
+ }
+ meta->map_ptr = reg->map_ptr;
+ meta->map_uid = reg->map_uid;
+ break;
+ case ARG_PTR_TO_MAP_KEY:
+ /* bpf_map_xxx(..., map_ptr, ..., key) call:
+ * check that [key, key + map->key_size) are within
+ * stack limits and initialized
+ */
+ if (!meta->map_ptr) {
+ /* in function declaration map_ptr must come before
+ * map_key, so that it's verified and known before
+ * we have to check map_key here. Otherwise it means
+ * that kernel subsystem misconfigured verifier
+ */
+ verbose(env, "invalid map_ptr to access map->key\n");
+ return -EACCES;
+ }
+ err = check_helper_mem_access(env, regno,
+ meta->map_ptr->key_size, false,
+ NULL);
+ break;
+ case ARG_PTR_TO_MAP_VALUE:
+ if (type_may_be_null(arg_type) && register_is_null(reg))
+ return 0;
+
+ /* bpf_map_xxx(..., map_ptr, ..., value) call:
+ * check [value, value + map->value_size) validity
+ */
+ if (!meta->map_ptr) {
+ /* kernel subsystem misconfigured verifier */
+ verbose(env, "invalid map_ptr to access map->value\n");
+ return -EACCES;
+ }
+ meta->raw_mode = arg_type & MEM_UNINIT;
+ err = check_helper_mem_access(env, regno,
+ meta->map_ptr->value_size, false,
+ meta);
+ break;
+ case ARG_PTR_TO_PERCPU_BTF_ID:
+ if (!reg->btf_id) {
+ verbose(env, "Helper has invalid btf_id in R%d\n", regno);
+ return -EACCES;
+ }
+ meta->ret_btf = reg->btf;
+ meta->ret_btf_id = reg->btf_id;
+ break;
+ case ARG_PTR_TO_SPIN_LOCK:
+ if (in_rbtree_lock_required_cb(env)) {
+ verbose(env, "can't spin_{lock,unlock} in rbtree cb\n");
+ return -EACCES;
+ }
+ if (meta->func_id == BPF_FUNC_spin_lock) {
+ err = process_spin_lock(env, regno, true);
+ if (err)
+ return err;
+ } else if (meta->func_id == BPF_FUNC_spin_unlock) {
+ err = process_spin_lock(env, regno, false);
+ if (err)
+ return err;
+ } else {
+ verbose(env, "verifier internal error\n");
+ return -EFAULT;
+ }
+ break;
+ case ARG_PTR_TO_TIMER:
+ err = process_timer_func(env, regno, meta);
+ if (err)
+ return err;
+ break;
+ case ARG_PTR_TO_FUNC:
+ meta->subprogno = reg->subprogno;
+ break;
+ case ARG_PTR_TO_MEM:
+ /* The access to this pointer is only checked when we hit the
+ * next is_mem_size argument below.
+ */
+ meta->raw_mode = arg_type & MEM_UNINIT;
+ if (arg_type & MEM_FIXED_SIZE) {
+ err = check_helper_mem_access(env, regno,
+ fn->arg_size[arg], false,
+ meta);
+ }
+ break;
+ case ARG_CONST_SIZE:
+ err = check_mem_size_reg(env, reg, regno, false, meta);
+ break;
+ case ARG_CONST_SIZE_OR_ZERO:
+ err = check_mem_size_reg(env, reg, regno, true, meta);
+ break;
+ case ARG_PTR_TO_DYNPTR:
+ err = process_dynptr_func(env, regno, insn_idx, arg_type, 0);
+ if (err)
+ return err;
+ break;
+ case ARG_CONST_ALLOC_SIZE_OR_ZERO:
+ if (!tnum_is_const(reg->var_off)) {
+ verbose(env, "R%d is not a known constant'\n",
+ regno);
+ return -EACCES;
+ }
+ meta->mem_size = reg->var_off.value;
+ err = mark_chain_precision(env, regno);
+ if (err)
+ return err;
+ break;
+ case ARG_PTR_TO_INT:
+ case ARG_PTR_TO_LONG:
+ {
+ int size = int_ptr_type_to_size(arg_type);
+
+ err = check_helper_mem_access(env, regno, size, false, meta);
+ if (err)
+ return err;
+ err = check_ptr_alignment(env, reg, 0, size, true);
+ break;
+ }
+ case ARG_PTR_TO_CONST_STR:
+ {
+ struct bpf_map *map = reg->map_ptr;
+ int map_off;
+ u64 map_addr;
+ char *str_ptr;
+
+ if (!bpf_map_is_rdonly(map)) {
+ verbose(env, "R%d does not point to a readonly map'\n", regno);
+ return -EACCES;
+ }
+
+ if (!tnum_is_const(reg->var_off)) {
+ verbose(env, "R%d is not a constant address'\n", regno);
+ return -EACCES;
+ }
+
+ if (!map->ops->map_direct_value_addr) {
+ verbose(env, "no direct value access support for this map type\n");
+ return -EACCES;
+ }
+
+ err = check_map_access(env, regno, reg->off,
+ map->value_size - reg->off, false,
+ ACCESS_HELPER);
+ if (err)
+ return err;
+
+ map_off = reg->off + reg->var_off.value;
+ err = map->ops->map_direct_value_addr(map, &map_addr, map_off);
+ if (err) {
+ verbose(env, "direct value access on string failed\n");
+ return err;
+ }
+
+ str_ptr = (char *)(long)(map_addr);
+ if (!strnchr(str_ptr + map_off, map->value_size - map_off, 0)) {
+ verbose(env, "string is not zero-terminated\n");
+ return -EINVAL;
+ }
+ break;
+ }
+ case ARG_PTR_TO_KPTR:
+ err = process_kptr_func(env, regno, meta);
+ if (err)
+ return err;
+ break;
+ }
+
+ return err;
+}
+
+static bool may_update_sockmap(struct bpf_verifier_env *env, int func_id)
+{
+ enum bpf_attach_type eatype = env->prog->expected_attach_type;
+ enum bpf_prog_type type = resolve_prog_type(env->prog);
+
+ if (func_id != BPF_FUNC_map_update_elem)
+ return false;
+
+ /* It's not possible to get access to a locked struct sock in these
+ * contexts, so updating is safe.
+ */
+ switch (type) {
+ case BPF_PROG_TYPE_TRACING:
+ if (eatype == BPF_TRACE_ITER)
+ return true;
+ break;
+ case BPF_PROG_TYPE_SOCKET_FILTER:
+ case BPF_PROG_TYPE_SCHED_CLS:
+ case BPF_PROG_TYPE_SCHED_ACT:
+ case BPF_PROG_TYPE_XDP:
+ case BPF_PROG_TYPE_SK_REUSEPORT:
+ case BPF_PROG_TYPE_FLOW_DISSECTOR:
+ case BPF_PROG_TYPE_SK_LOOKUP:
+ return true;
+ default:
+ break;
+ }
+
+ verbose(env, "cannot update sockmap in this context\n");
+ return false;
+}
+
+static bool allow_tail_call_in_subprogs(struct bpf_verifier_env *env)
+{
+ return env->prog->jit_requested &&
+ bpf_jit_supports_subprog_tailcalls();
+}
+
+static int check_map_func_compatibility(struct bpf_verifier_env *env,
+ struct bpf_map *map, int func_id)
+{
+ if (!map)
+ return 0;
+
+ /* We need a two way check, first is from map perspective ... */
+ switch (map->map_type) {
+ case BPF_MAP_TYPE_PROG_ARRAY:
+ if (func_id != BPF_FUNC_tail_call)
+ goto error;
+ break;
+ case BPF_MAP_TYPE_PERF_EVENT_ARRAY:
+ if (func_id != BPF_FUNC_perf_event_read &&
+ func_id != BPF_FUNC_perf_event_output &&
+ func_id != BPF_FUNC_skb_output &&
+ func_id != BPF_FUNC_perf_event_read_value &&
+ func_id != BPF_FUNC_xdp_output)
+ goto error;
+ break;
+ case BPF_MAP_TYPE_RINGBUF:
+ if (func_id != BPF_FUNC_ringbuf_output &&
+ func_id != BPF_FUNC_ringbuf_reserve &&
+ func_id != BPF_FUNC_ringbuf_query &&
+ func_id != BPF_FUNC_ringbuf_reserve_dynptr &&
+ func_id != BPF_FUNC_ringbuf_submit_dynptr &&
+ func_id != BPF_FUNC_ringbuf_discard_dynptr)
+ goto error;
+ break;
+ case BPF_MAP_TYPE_USER_RINGBUF:
+ if (func_id != BPF_FUNC_user_ringbuf_drain)
+ goto error;
+ break;
+ case BPF_MAP_TYPE_STACK_TRACE:
+ if (func_id != BPF_FUNC_get_stackid)
+ goto error;
+ break;
+ case BPF_MAP_TYPE_CGROUP_ARRAY:
+ if (func_id != BPF_FUNC_skb_under_cgroup &&
+ func_id != BPF_FUNC_current_task_under_cgroup)
+ goto error;
+ break;
+ case BPF_MAP_TYPE_CGROUP_STORAGE:
+ case BPF_MAP_TYPE_PERCPU_CGROUP_STORAGE:
+ if (func_id != BPF_FUNC_get_local_storage)
+ goto error;
+ break;
+ case BPF_MAP_TYPE_DEVMAP:
+ case BPF_MAP_TYPE_DEVMAP_HASH:
+ if (func_id != BPF_FUNC_redirect_map &&
+ func_id != BPF_FUNC_map_lookup_elem)
+ goto error;
+ break;
+ /* Restrict bpf side of cpumap and xskmap, open when use-cases
+ * appear.
+ */
+ case BPF_MAP_TYPE_CPUMAP:
+ if (func_id != BPF_FUNC_redirect_map)
+ goto error;
+ break;
+ case BPF_MAP_TYPE_XSKMAP:
+ if (func_id != BPF_FUNC_redirect_map &&
+ func_id != BPF_FUNC_map_lookup_elem)
+ goto error;
+ break;
+ case BPF_MAP_TYPE_ARRAY_OF_MAPS:
+ case BPF_MAP_TYPE_HASH_OF_MAPS:
+ if (func_id != BPF_FUNC_map_lookup_elem)
+ goto error;
+ break;
+ case BPF_MAP_TYPE_SOCKMAP:
+ if (func_id != BPF_FUNC_sk_redirect_map &&
+ func_id != BPF_FUNC_sock_map_update &&
+ func_id != BPF_FUNC_map_delete_elem &&
+ func_id != BPF_FUNC_msg_redirect_map &&
+ func_id != BPF_FUNC_sk_select_reuseport &&
+ func_id != BPF_FUNC_map_lookup_elem &&
+ !may_update_sockmap(env, func_id))
+ goto error;
+ break;
+ case BPF_MAP_TYPE_SOCKHASH:
+ if (func_id != BPF_FUNC_sk_redirect_hash &&
+ func_id != BPF_FUNC_sock_hash_update &&
+ func_id != BPF_FUNC_map_delete_elem &&
+ func_id != BPF_FUNC_msg_redirect_hash &&
+ func_id != BPF_FUNC_sk_select_reuseport &&
+ func_id != BPF_FUNC_map_lookup_elem &&
+ !may_update_sockmap(env, func_id))
+ goto error;
+ break;
+ case BPF_MAP_TYPE_REUSEPORT_SOCKARRAY:
+ if (func_id != BPF_FUNC_sk_select_reuseport)
+ goto error;
+ break;
+ case BPF_MAP_TYPE_QUEUE:
+ case BPF_MAP_TYPE_STACK:
+ if (func_id != BPF_FUNC_map_peek_elem &&
+ func_id != BPF_FUNC_map_pop_elem &&
+ func_id != BPF_FUNC_map_push_elem)
+ goto error;
+ break;
+ case BPF_MAP_TYPE_SK_STORAGE:
+ if (func_id != BPF_FUNC_sk_storage_get &&
+ func_id != BPF_FUNC_sk_storage_delete &&
+ func_id != BPF_FUNC_kptr_xchg)
+ goto error;
+ break;
+ case BPF_MAP_TYPE_INODE_STORAGE:
+ if (func_id != BPF_FUNC_inode_storage_get &&
+ func_id != BPF_FUNC_inode_storage_delete &&
+ func_id != BPF_FUNC_kptr_xchg)
+ goto error;
+ break;
+ case BPF_MAP_TYPE_TASK_STORAGE:
+ if (func_id != BPF_FUNC_task_storage_get &&
+ func_id != BPF_FUNC_task_storage_delete &&
+ func_id != BPF_FUNC_kptr_xchg)
+ goto error;
+ break;
+ case BPF_MAP_TYPE_CGRP_STORAGE:
+ if (func_id != BPF_FUNC_cgrp_storage_get &&
+ func_id != BPF_FUNC_cgrp_storage_delete &&
+ func_id != BPF_FUNC_kptr_xchg)
+ goto error;
+ break;
+ case BPF_MAP_TYPE_BLOOM_FILTER:
+ if (func_id != BPF_FUNC_map_peek_elem &&
+ func_id != BPF_FUNC_map_push_elem)
+ goto error;
+ break;
+ default:
+ break;
+ }
+
+ /* ... and second from the function itself. */
+ switch (func_id) {
+ case BPF_FUNC_tail_call:
+ if (map->map_type != BPF_MAP_TYPE_PROG_ARRAY)
+ goto error;
+ if (env->subprog_cnt > 1 && !allow_tail_call_in_subprogs(env)) {
+ verbose(env, "tail_calls are not allowed in non-JITed programs with bpf-to-bpf calls\n");
+ return -EINVAL;
+ }
+ break;
+ case BPF_FUNC_perf_event_read:
+ case BPF_FUNC_perf_event_output:
+ case BPF_FUNC_perf_event_read_value:
+ case BPF_FUNC_skb_output:
+ case BPF_FUNC_xdp_output:
+ if (map->map_type != BPF_MAP_TYPE_PERF_EVENT_ARRAY)
+ goto error;
+ break;
+ case BPF_FUNC_ringbuf_output:
+ case BPF_FUNC_ringbuf_reserve:
+ case BPF_FUNC_ringbuf_query:
+ case BPF_FUNC_ringbuf_reserve_dynptr:
+ case BPF_FUNC_ringbuf_submit_dynptr:
+ case BPF_FUNC_ringbuf_discard_dynptr:
+ if (map->map_type != BPF_MAP_TYPE_RINGBUF)
+ goto error;
+ break;
+ case BPF_FUNC_user_ringbuf_drain:
+ if (map->map_type != BPF_MAP_TYPE_USER_RINGBUF)
+ goto error;
+ break;
+ case BPF_FUNC_get_stackid:
+ if (map->map_type != BPF_MAP_TYPE_STACK_TRACE)
+ goto error;
+ break;
+ case BPF_FUNC_current_task_under_cgroup:
+ case BPF_FUNC_skb_under_cgroup:
+ if (map->map_type != BPF_MAP_TYPE_CGROUP_ARRAY)
+ goto error;
+ break;
+ case BPF_FUNC_redirect_map:
+ if (map->map_type != BPF_MAP_TYPE_DEVMAP &&
+ map->map_type != BPF_MAP_TYPE_DEVMAP_HASH &&
+ map->map_type != BPF_MAP_TYPE_CPUMAP &&
+ map->map_type != BPF_MAP_TYPE_XSKMAP)
+ goto error;
+ break;
+ case BPF_FUNC_sk_redirect_map:
+ case BPF_FUNC_msg_redirect_map:
+ case BPF_FUNC_sock_map_update:
+ if (map->map_type != BPF_MAP_TYPE_SOCKMAP)
+ goto error;
+ break;
+ case BPF_FUNC_sk_redirect_hash:
+ case BPF_FUNC_msg_redirect_hash:
+ case BPF_FUNC_sock_hash_update:
+ if (map->map_type != BPF_MAP_TYPE_SOCKHASH)
+ goto error;
+ break;
+ case BPF_FUNC_get_local_storage:
+ if (map->map_type != BPF_MAP_TYPE_CGROUP_STORAGE &&
+ map->map_type != BPF_MAP_TYPE_PERCPU_CGROUP_STORAGE)
+ goto error;
+ break;
+ case BPF_FUNC_sk_select_reuseport:
+ if (map->map_type != BPF_MAP_TYPE_REUSEPORT_SOCKARRAY &&
+ map->map_type != BPF_MAP_TYPE_SOCKMAP &&
+ map->map_type != BPF_MAP_TYPE_SOCKHASH)
+ goto error;
+ break;
+ case BPF_FUNC_map_pop_elem:
+ if (map->map_type != BPF_MAP_TYPE_QUEUE &&
+ map->map_type != BPF_MAP_TYPE_STACK)
+ goto error;
+ break;
+ case BPF_FUNC_map_peek_elem:
+ case BPF_FUNC_map_push_elem:
+ if (map->map_type != BPF_MAP_TYPE_QUEUE &&
+ map->map_type != BPF_MAP_TYPE_STACK &&
+ map->map_type != BPF_MAP_TYPE_BLOOM_FILTER)
+ goto error;
+ break;
+ case BPF_FUNC_map_lookup_percpu_elem:
+ if (map->map_type != BPF_MAP_TYPE_PERCPU_ARRAY &&
+ map->map_type != BPF_MAP_TYPE_PERCPU_HASH &&
+ map->map_type != BPF_MAP_TYPE_LRU_PERCPU_HASH)
+ goto error;
+ break;
+ case BPF_FUNC_sk_storage_get:
+ case BPF_FUNC_sk_storage_delete:
+ if (map->map_type != BPF_MAP_TYPE_SK_STORAGE)
+ goto error;
+ break;
+ case BPF_FUNC_inode_storage_get:
+ case BPF_FUNC_inode_storage_delete:
+ if (map->map_type != BPF_MAP_TYPE_INODE_STORAGE)
+ goto error;
+ break;
+ case BPF_FUNC_task_storage_get:
+ case BPF_FUNC_task_storage_delete:
+ if (map->map_type != BPF_MAP_TYPE_TASK_STORAGE)
+ goto error;
+ break;
+ case BPF_FUNC_cgrp_storage_get:
+ case BPF_FUNC_cgrp_storage_delete:
+ if (map->map_type != BPF_MAP_TYPE_CGRP_STORAGE)
+ goto error;
+ break;
+ default:
+ break;
+ }
+
+ return 0;
+error:
+ verbose(env, "cannot pass map_type %d into func %s#%d\n",
+ map->map_type, func_id_name(func_id), func_id);
+ return -EINVAL;
+}
+
+static bool check_raw_mode_ok(const struct bpf_func_proto *fn)
+{
+ int count = 0;
+
+ if (fn->arg1_type == ARG_PTR_TO_UNINIT_MEM)
+ count++;
+ if (fn->arg2_type == ARG_PTR_TO_UNINIT_MEM)
+ count++;
+ if (fn->arg3_type == ARG_PTR_TO_UNINIT_MEM)
+ count++;
+ if (fn->arg4_type == ARG_PTR_TO_UNINIT_MEM)
+ count++;
+ if (fn->arg5_type == ARG_PTR_TO_UNINIT_MEM)
+ count++;
+
+ /* We only support one arg being in raw mode at the moment,
+ * which is sufficient for the helper functions we have
+ * right now.
+ */
+ return count <= 1;
+}
+
+static bool check_args_pair_invalid(const struct bpf_func_proto *fn, int arg)
+{
+ bool is_fixed = fn->arg_type[arg] & MEM_FIXED_SIZE;
+ bool has_size = fn->arg_size[arg] != 0;
+ bool is_next_size = false;
+
+ if (arg + 1 < ARRAY_SIZE(fn->arg_type))
+ is_next_size = arg_type_is_mem_size(fn->arg_type[arg + 1]);
+
+ if (base_type(fn->arg_type[arg]) != ARG_PTR_TO_MEM)
+ return is_next_size;
+
+ return has_size == is_next_size || is_next_size == is_fixed;
+}
+
+static bool check_arg_pair_ok(const struct bpf_func_proto *fn)
+{
+ /* bpf_xxx(..., buf, len) call will access 'len'
+ * bytes from memory 'buf'. Both arg types need
+ * to be paired, so make sure there's no buggy
+ * helper function specification.
+ */
+ if (arg_type_is_mem_size(fn->arg1_type) ||
+ check_args_pair_invalid(fn, 0) ||
+ check_args_pair_invalid(fn, 1) ||
+ check_args_pair_invalid(fn, 2) ||
+ check_args_pair_invalid(fn, 3) ||
+ check_args_pair_invalid(fn, 4))
+ return false;
+
+ return true;
+}
+
+static bool check_btf_id_ok(const struct bpf_func_proto *fn)
+{
+ int i;
+
+ for (i = 0; i < ARRAY_SIZE(fn->arg_type); i++) {
+ if (base_type(fn->arg_type[i]) == ARG_PTR_TO_BTF_ID)
+ return !!fn->arg_btf_id[i];
+ if (base_type(fn->arg_type[i]) == ARG_PTR_TO_SPIN_LOCK)
+ return fn->arg_btf_id[i] == BPF_PTR_POISON;
+ if (base_type(fn->arg_type[i]) != ARG_PTR_TO_BTF_ID && fn->arg_btf_id[i] &&
+ /* arg_btf_id and arg_size are in a union. */
+ (base_type(fn->arg_type[i]) != ARG_PTR_TO_MEM ||
+ !(fn->arg_type[i] & MEM_FIXED_SIZE)))
+ return false;
+ }
+
+ return true;
+}
+
+static int check_func_proto(const struct bpf_func_proto *fn, int func_id)
+{
+ return check_raw_mode_ok(fn) &&
+ check_arg_pair_ok(fn) &&
+ check_btf_id_ok(fn) ? 0 : -EINVAL;
+}
+
+/* Packet data might have moved, any old PTR_TO_PACKET[_META,_END]
+ * are now invalid, so turn them into unknown SCALAR_VALUE.
+ *
+ * This also applies to dynptr slices belonging to skb and xdp dynptrs,
+ * since these slices point to packet data.
+ */
+static void clear_all_pkt_pointers(struct bpf_verifier_env *env)
+{
+ struct bpf_func_state *state;
+ struct bpf_reg_state *reg;
+
+ bpf_for_each_reg_in_vstate(env->cur_state, state, reg, ({
+ if (reg_is_pkt_pointer_any(reg) || reg_is_dynptr_slice_pkt(reg))
+ mark_reg_invalid(env, reg);
+ }));
+}
+
+enum {
+ AT_PKT_END = -1,
+ BEYOND_PKT_END = -2,
+};
+
+static void mark_pkt_end(struct bpf_verifier_state *vstate, int regn, bool range_open)
+{
+ struct bpf_func_state *state = vstate->frame[vstate->curframe];
+ struct bpf_reg_state *reg = &state->regs[regn];
+
+ if (reg->type != PTR_TO_PACKET)
+ /* PTR_TO_PACKET_META is not supported yet */
+ return;
+
+ /* The 'reg' is pkt > pkt_end or pkt >= pkt_end.
+ * How far beyond pkt_end it goes is unknown.
+ * if (!range_open) it's the case of pkt >= pkt_end
+ * if (range_open) it's the case of pkt > pkt_end
+ * hence this pointer is at least 1 byte bigger than pkt_end
+ */
+ if (range_open)
+ reg->range = BEYOND_PKT_END;
+ else
+ reg->range = AT_PKT_END;
+}
+
+/* The pointer with the specified id has released its reference to kernel
+ * resources. Identify all copies of the same pointer and clear the reference.
+ */
+static int release_reference(struct bpf_verifier_env *env,
+ int ref_obj_id)
+{
+ struct bpf_func_state *state;
+ struct bpf_reg_state *reg;
+ int err;
+
+ err = release_reference_state(cur_func(env), ref_obj_id);
+ if (err)
+ return err;
+
+ bpf_for_each_reg_in_vstate(env->cur_state, state, reg, ({
+ if (reg->ref_obj_id == ref_obj_id)
+ mark_reg_invalid(env, reg);
+ }));
+
+ return 0;
+}
+
+static void invalidate_non_owning_refs(struct bpf_verifier_env *env)
+{
+ struct bpf_func_state *unused;
+ struct bpf_reg_state *reg;
+
+ bpf_for_each_reg_in_vstate(env->cur_state, unused, reg, ({
+ if (type_is_non_owning_ref(reg->type))
+ mark_reg_invalid(env, reg);
+ }));
+}
+
+static void clear_caller_saved_regs(struct bpf_verifier_env *env,
+ struct bpf_reg_state *regs)
+{
+ int i;
+
+ /* after the call registers r0 - r5 were scratched */
+ for (i = 0; i < CALLER_SAVED_REGS; i++) {
+ mark_reg_not_init(env, regs, caller_saved[i]);
+ __check_reg_arg(env, regs, caller_saved[i], DST_OP_NO_MARK);
+ }
+}
+
+typedef int (*set_callee_state_fn)(struct bpf_verifier_env *env,
+ struct bpf_func_state *caller,
+ struct bpf_func_state *callee,
+ int insn_idx);
+
+static int set_callee_state(struct bpf_verifier_env *env,
+ struct bpf_func_state *caller,
+ struct bpf_func_state *callee, int insn_idx);
+
+static int setup_func_entry(struct bpf_verifier_env *env, int subprog, int callsite,
+ set_callee_state_fn set_callee_state_cb,
+ struct bpf_verifier_state *state)
+{
+ struct bpf_func_state *caller, *callee;
+ int err;
+
+ if (state->curframe + 1 >= MAX_CALL_FRAMES) {
+ verbose(env, "the call stack of %d frames is too deep\n",
+ state->curframe + 2);
+ return -E2BIG;
+ }
+
+ if (state->frame[state->curframe + 1]) {
+ verbose(env, "verifier bug. Frame %d already allocated\n",
+ state->curframe + 1);
+ return -EFAULT;
+ }
+
+ caller = state->frame[state->curframe];
+ callee = kzalloc(sizeof(*callee), GFP_KERNEL);
+ if (!callee)
+ return -ENOMEM;
+ state->frame[state->curframe + 1] = callee;
+
+ /* callee cannot access r0, r6 - r9 for reading and has to write
+ * into its own stack before reading from it.
+ * callee can read/write into caller's stack
+ */
+ init_func_state(env, callee,
+ /* remember the callsite, it will be used by bpf_exit */
+ callsite,
+ state->curframe + 1 /* frameno within this callchain */,
+ subprog /* subprog number within this prog */);
+ /* Transfer references to the callee */
+ err = copy_reference_state(callee, caller);
+ err = err ?: set_callee_state_cb(env, caller, callee, callsite);
+ if (err)
+ goto err_out;
+
+ /* only increment it after check_reg_arg() finished */
+ state->curframe++;
+
+ return 0;
+
+err_out:
+ free_func_state(callee);
+ state->frame[state->curframe + 1] = NULL;
+ return err;
+}
+
+static int push_callback_call(struct bpf_verifier_env *env, struct bpf_insn *insn,
+ int insn_idx, int subprog,
+ set_callee_state_fn set_callee_state_cb)
+{
+ struct bpf_verifier_state *state = env->cur_state, *callback_state;
+ struct bpf_func_state *caller, *callee;
+ int err;
+
+ caller = state->frame[state->curframe];
+ err = btf_check_subprog_call(env, subprog, caller->regs);
+ if (err == -EFAULT)
+ return err;
+
+ /* set_callee_state is used for direct subprog calls, but we are
+ * interested in validating only BPF helpers that can call subprogs as
+ * callbacks
+ */
+ if (bpf_pseudo_kfunc_call(insn) &&
+ !is_sync_callback_calling_kfunc(insn->imm)) {
+ verbose(env, "verifier bug: kfunc %s#%d not marked as callback-calling\n",
+ func_id_name(insn->imm), insn->imm);
+ return -EFAULT;
+ } else if (!bpf_pseudo_kfunc_call(insn) &&
+ !is_callback_calling_function(insn->imm)) { /* helper */
+ verbose(env, "verifier bug: helper %s#%d not marked as callback-calling\n",
+ func_id_name(insn->imm), insn->imm);
+ return -EFAULT;
+ }
+
+ if (insn->code == (BPF_JMP | BPF_CALL) &&
+ insn->src_reg == 0 &&
+ insn->imm == BPF_FUNC_timer_set_callback) {
+ struct bpf_verifier_state *async_cb;
+
+ /* there is no real recursion here. timer callbacks are async */
+ env->subprog_info[subprog].is_async_cb = true;
+ async_cb = push_async_cb(env, env->subprog_info[subprog].start,
+ insn_idx, subprog);
+ if (!async_cb)
+ return -EFAULT;
+ callee = async_cb->frame[0];
+ callee->async_entry_cnt = caller->async_entry_cnt + 1;
+
+ /* Convert bpf_timer_set_callback() args into timer callback args */
+ err = set_callee_state_cb(env, caller, callee, insn_idx);
+ if (err)
+ return err;
+
+ return 0;
+ }
+
+ /* for callback functions enqueue entry to callback and
+ * proceed with next instruction within current frame.
+ */
+ callback_state = push_stack(env, env->subprog_info[subprog].start, insn_idx, false);
+ if (!callback_state)
+ return -ENOMEM;
+
+ err = setup_func_entry(env, subprog, insn_idx, set_callee_state_cb,
+ callback_state);
+ if (err)
+ return err;
+
+ callback_state->callback_unroll_depth++;
+ callback_state->frame[callback_state->curframe - 1]->callback_depth++;
+ caller->callback_depth = 0;
+ return 0;
+}
+
+static int check_func_call(struct bpf_verifier_env *env, struct bpf_insn *insn,
+ int *insn_idx)
+{
+ struct bpf_verifier_state *state = env->cur_state;
+ struct bpf_func_state *caller;
+ int err, subprog, target_insn;
+
+ target_insn = *insn_idx + insn->imm + 1;
+ subprog = find_subprog(env, target_insn);
+ if (subprog < 0) {
+ verbose(env, "verifier bug. No program starts at insn %d\n", target_insn);
+ return -EFAULT;
+ }
+
+ caller = state->frame[state->curframe];
+ err = btf_check_subprog_call(env, subprog, caller->regs);
+ if (err == -EFAULT)
+ return err;
+ if (subprog_is_global(env, subprog)) {
+ if (err) {
+ verbose(env, "Caller passes invalid args into func#%d\n", subprog);
+ return err;
+ }
+
+ if (env->log.level & BPF_LOG_LEVEL)
+ verbose(env, "Func#%d is global and valid. Skipping.\n", subprog);
+ clear_caller_saved_regs(env, caller->regs);
+
+ /* All global functions return a 64-bit SCALAR_VALUE */
+ mark_reg_unknown(env, caller->regs, BPF_REG_0);
+ caller->regs[BPF_REG_0].subreg_def = DEF_NOT_SUBREG;
+
+ /* continue with next insn after call */
+ return 0;
+ }
+
+ /* for regular function entry setup new frame and continue
+ * from that frame.
+ */
+ err = setup_func_entry(env, subprog, *insn_idx, set_callee_state, state);
+ if (err)
+ return err;
+
+ clear_caller_saved_regs(env, caller->regs);
+
+ /* and go analyze first insn of the callee */
+ *insn_idx = env->subprog_info[subprog].start - 1;
+
+ if (env->log.level & BPF_LOG_LEVEL) {
+ verbose(env, "caller:\n");
+ print_verifier_state(env, caller, true);
+ verbose(env, "callee:\n");
+ print_verifier_state(env, state->frame[state->curframe], true);
+ }
+
+ return 0;
+}
+
+int map_set_for_each_callback_args(struct bpf_verifier_env *env,
+ struct bpf_func_state *caller,
+ struct bpf_func_state *callee)
+{
+ /* bpf_for_each_map_elem(struct bpf_map *map, void *callback_fn,
+ * void *callback_ctx, u64 flags);
+ * callback_fn(struct bpf_map *map, void *key, void *value,
+ * void *callback_ctx);
+ */
+ callee->regs[BPF_REG_1] = caller->regs[BPF_REG_1];
+
+ callee->regs[BPF_REG_2].type = PTR_TO_MAP_KEY;
+ __mark_reg_known_zero(&callee->regs[BPF_REG_2]);
+ callee->regs[BPF_REG_2].map_ptr = caller->regs[BPF_REG_1].map_ptr;
+
+ callee->regs[BPF_REG_3].type = PTR_TO_MAP_VALUE;
+ __mark_reg_known_zero(&callee->regs[BPF_REG_3]);
+ callee->regs[BPF_REG_3].map_ptr = caller->regs[BPF_REG_1].map_ptr;
+
+ /* pointer to stack or null */
+ callee->regs[BPF_REG_4] = caller->regs[BPF_REG_3];
+
+ /* unused */
+ __mark_reg_not_init(env, &callee->regs[BPF_REG_5]);
+ return 0;
+}
+
+static int set_callee_state(struct bpf_verifier_env *env,
+ struct bpf_func_state *caller,
+ struct bpf_func_state *callee, int insn_idx)
+{
+ int i;
+
+ /* copy r1 - r5 args that callee can access. The copy includes parent
+ * pointers, which connects us up to the liveness chain
+ */
+ for (i = BPF_REG_1; i <= BPF_REG_5; i++)
+ callee->regs[i] = caller->regs[i];
+ return 0;
+}
+
+static int set_map_elem_callback_state(struct bpf_verifier_env *env,
+ struct bpf_func_state *caller,
+ struct bpf_func_state *callee,
+ int insn_idx)
+{
+ struct bpf_insn_aux_data *insn_aux = &env->insn_aux_data[insn_idx];
+ struct bpf_map *map;
+ int err;
+
+ if (bpf_map_ptr_poisoned(insn_aux)) {
+ verbose(env, "tail_call abusing map_ptr\n");
+ return -EINVAL;
+ }
+
+ map = BPF_MAP_PTR(insn_aux->map_ptr_state);
+ if (!map->ops->map_set_for_each_callback_args ||
+ !map->ops->map_for_each_callback) {
+ verbose(env, "callback function not allowed for map\n");
+ return -ENOTSUPP;
+ }
+
+ err = map->ops->map_set_for_each_callback_args(env, caller, callee);
+ if (err)
+ return err;
+
+ callee->in_callback_fn = true;
+ callee->callback_ret_range = tnum_range(0, 1);
+ return 0;
+}
+
+static int set_loop_callback_state(struct bpf_verifier_env *env,
+ struct bpf_func_state *caller,
+ struct bpf_func_state *callee,
+ int insn_idx)
+{
+ /* bpf_loop(u32 nr_loops, void *callback_fn, void *callback_ctx,
+ * u64 flags);
+ * callback_fn(u32 index, void *callback_ctx);
+ */
+ callee->regs[BPF_REG_1].type = SCALAR_VALUE;
+ callee->regs[BPF_REG_2] = caller->regs[BPF_REG_3];
+
+ /* unused */
+ __mark_reg_not_init(env, &callee->regs[BPF_REG_3]);
+ __mark_reg_not_init(env, &callee->regs[BPF_REG_4]);
+ __mark_reg_not_init(env, &callee->regs[BPF_REG_5]);
+
+ callee->in_callback_fn = true;
+ callee->callback_ret_range = tnum_range(0, 1);
+ return 0;
+}
+
+static int set_timer_callback_state(struct bpf_verifier_env *env,
+ struct bpf_func_state *caller,
+ struct bpf_func_state *callee,
+ int insn_idx)
+{
+ struct bpf_map *map_ptr = caller->regs[BPF_REG_1].map_ptr;
+
+ /* bpf_timer_set_callback(struct bpf_timer *timer, void *callback_fn);
+ * callback_fn(struct bpf_map *map, void *key, void *value);
+ */
+ callee->regs[BPF_REG_1].type = CONST_PTR_TO_MAP;
+ __mark_reg_known_zero(&callee->regs[BPF_REG_1]);
+ callee->regs[BPF_REG_1].map_ptr = map_ptr;
+
+ callee->regs[BPF_REG_2].type = PTR_TO_MAP_KEY;
+ __mark_reg_known_zero(&callee->regs[BPF_REG_2]);
+ callee->regs[BPF_REG_2].map_ptr = map_ptr;
+
+ callee->regs[BPF_REG_3].type = PTR_TO_MAP_VALUE;
+ __mark_reg_known_zero(&callee->regs[BPF_REG_3]);
+ callee->regs[BPF_REG_3].map_ptr = map_ptr;
+
+ /* unused */
+ __mark_reg_not_init(env, &callee->regs[BPF_REG_4]);
+ __mark_reg_not_init(env, &callee->regs[BPF_REG_5]);
+ callee->in_async_callback_fn = true;
+ callee->callback_ret_range = tnum_range(0, 1);
+ return 0;
+}
+
+static int set_find_vma_callback_state(struct bpf_verifier_env *env,
+ struct bpf_func_state *caller,
+ struct bpf_func_state *callee,
+ int insn_idx)
+{
+ /* bpf_find_vma(struct task_struct *task, u64 addr,
+ * void *callback_fn, void *callback_ctx, u64 flags)
+ * (callback_fn)(struct task_struct *task,
+ * struct vm_area_struct *vma, void *callback_ctx);
+ */
+ callee->regs[BPF_REG_1] = caller->regs[BPF_REG_1];
+
+ callee->regs[BPF_REG_2].type = PTR_TO_BTF_ID;
+ __mark_reg_known_zero(&callee->regs[BPF_REG_2]);
+ callee->regs[BPF_REG_2].btf = btf_vmlinux;
+ callee->regs[BPF_REG_2].btf_id = btf_tracing_ids[BTF_TRACING_TYPE_VMA],
+
+ /* pointer to stack or null */
+ callee->regs[BPF_REG_3] = caller->regs[BPF_REG_4];
+
+ /* unused */
+ __mark_reg_not_init(env, &callee->regs[BPF_REG_4]);
+ __mark_reg_not_init(env, &callee->regs[BPF_REG_5]);
+ callee->in_callback_fn = true;
+ callee->callback_ret_range = tnum_range(0, 1);
+ return 0;
+}
+
+static int set_user_ringbuf_callback_state(struct bpf_verifier_env *env,
+ struct bpf_func_state *caller,
+ struct bpf_func_state *callee,
+ int insn_idx)
+{
+ /* bpf_user_ringbuf_drain(struct bpf_map *map, void *callback_fn, void
+ * callback_ctx, u64 flags);
+ * callback_fn(const struct bpf_dynptr_t* dynptr, void *callback_ctx);
+ */
+ __mark_reg_not_init(env, &callee->regs[BPF_REG_0]);
+ mark_dynptr_cb_reg(env, &callee->regs[BPF_REG_1], BPF_DYNPTR_TYPE_LOCAL);
+ callee->regs[BPF_REG_2] = caller->regs[BPF_REG_3];
+
+ /* unused */
+ __mark_reg_not_init(env, &callee->regs[BPF_REG_3]);
+ __mark_reg_not_init(env, &callee->regs[BPF_REG_4]);
+ __mark_reg_not_init(env, &callee->regs[BPF_REG_5]);
+
+ callee->in_callback_fn = true;
+ callee->callback_ret_range = tnum_range(0, 1);
+ return 0;
+}
+
+static int set_rbtree_add_callback_state(struct bpf_verifier_env *env,
+ struct bpf_func_state *caller,
+ struct bpf_func_state *callee,
+ int insn_idx)
+{
+ /* void bpf_rbtree_add_impl(struct bpf_rb_root *root, struct bpf_rb_node *node,
+ * bool (less)(struct bpf_rb_node *a, const struct bpf_rb_node *b));
+ *
+ * 'struct bpf_rb_node *node' arg to bpf_rbtree_add_impl is the same PTR_TO_BTF_ID w/ offset
+ * that 'less' callback args will be receiving. However, 'node' arg was release_reference'd
+ * by this point, so look at 'root'
+ */
+ struct btf_field *field;
+
+ field = reg_find_field_offset(&caller->regs[BPF_REG_1], caller->regs[BPF_REG_1].off,
+ BPF_RB_ROOT);
+ if (!field || !field->graph_root.value_btf_id)
+ return -EFAULT;
+
+ mark_reg_graph_node(callee->regs, BPF_REG_1, &field->graph_root);
+ ref_set_non_owning(env, &callee->regs[BPF_REG_1]);
+ mark_reg_graph_node(callee->regs, BPF_REG_2, &field->graph_root);
+ ref_set_non_owning(env, &callee->regs[BPF_REG_2]);
+
+ __mark_reg_not_init(env, &callee->regs[BPF_REG_3]);
+ __mark_reg_not_init(env, &callee->regs[BPF_REG_4]);
+ __mark_reg_not_init(env, &callee->regs[BPF_REG_5]);
+ callee->in_callback_fn = true;
+ callee->callback_ret_range = tnum_range(0, 1);
+ return 0;
+}
+
+static bool is_rbtree_lock_required_kfunc(u32 btf_id);
+
+/* Are we currently verifying the callback for a rbtree helper that must
+ * be called with lock held? If so, no need to complain about unreleased
+ * lock
+ */
+static bool in_rbtree_lock_required_cb(struct bpf_verifier_env *env)
+{
+ struct bpf_verifier_state *state = env->cur_state;
+ struct bpf_insn *insn = env->prog->insnsi;
+ struct bpf_func_state *callee;
+ int kfunc_btf_id;
+
+ if (!state->curframe)
+ return false;
+
+ callee = state->frame[state->curframe];
+
+ if (!callee->in_callback_fn)
+ return false;
+
+ kfunc_btf_id = insn[callee->callsite].imm;
+ return is_rbtree_lock_required_kfunc(kfunc_btf_id);
+}
+
+static int prepare_func_exit(struct bpf_verifier_env *env, int *insn_idx)
+{
+ struct bpf_verifier_state *state = env->cur_state, *prev_st;
+ struct bpf_func_state *caller, *callee;
+ struct bpf_reg_state *r0;
+ bool in_callback_fn;
+ int err;
+
+ callee = state->frame[state->curframe];
+ r0 = &callee->regs[BPF_REG_0];
+ if (r0->type == PTR_TO_STACK) {
+ /* technically it's ok to return caller's stack pointer
+ * (or caller's caller's pointer) back to the caller,
+ * since these pointers are valid. Only current stack
+ * pointer will be invalid as soon as function exits,
+ * but let's be conservative
+ */
+ verbose(env, "cannot return stack pointer to the caller\n");
+ return -EINVAL;
+ }
+
+ caller = state->frame[state->curframe - 1];
+ if (callee->in_callback_fn) {
+ /* enforce R0 return value range [0, 1]. */
+ struct tnum range = callee->callback_ret_range;
+
+ if (r0->type != SCALAR_VALUE) {
+ verbose(env, "R0 not a scalar value\n");
+ return -EACCES;
+ }
+
+ /* we are going to rely on register's precise value */
+ err = mark_reg_read(env, r0, r0->parent, REG_LIVE_READ64);
+ err = err ?: mark_chain_precision(env, BPF_REG_0);
+ if (err)
+ return err;
+
+ if (!tnum_in(range, r0->var_off)) {
+ verbose_invalid_scalar(env, r0, &range, "callback return", "R0");
+ return -EINVAL;
+ }
+ if (!calls_callback(env, callee->callsite)) {
+ verbose(env, "BUG: in callback at %d, callsite %d !calls_callback\n",
+ *insn_idx, callee->callsite);
+ return -EFAULT;
+ }
+ } else {
+ /* return to the caller whatever r0 had in the callee */
+ caller->regs[BPF_REG_0] = *r0;
+ }
+
+ /* callback_fn frame should have released its own additions to parent's
+ * reference state at this point, or check_reference_leak would
+ * complain, hence it must be the same as the caller. There is no need
+ * to copy it back.
+ */
+ if (!callee->in_callback_fn) {
+ /* Transfer references to the caller */
+ err = copy_reference_state(caller, callee);
+ if (err)
+ return err;
+ }
+
+ /* for callbacks like bpf_loop or bpf_for_each_map_elem go back to callsite,
+ * there function call logic would reschedule callback visit. If iteration
+ * converges is_state_visited() would prune that visit eventually.
+ */
+ in_callback_fn = callee->in_callback_fn;
+ if (in_callback_fn)
+ *insn_idx = callee->callsite;
+ else
+ *insn_idx = callee->callsite + 1;
+
+ if (env->log.level & BPF_LOG_LEVEL) {
+ verbose(env, "returning from callee:\n");
+ print_verifier_state(env, callee, true);
+ verbose(env, "to caller at %d:\n", *insn_idx);
+ print_verifier_state(env, caller, true);
+ }
+ /* clear everything in the callee */
+ free_func_state(callee);
+ state->frame[state->curframe--] = NULL;
+
+ /* for callbacks widen imprecise scalars to make programs like below verify:
+ *
+ * struct ctx { int i; }
+ * void cb(int idx, struct ctx *ctx) { ctx->i++; ... }
+ * ...
+ * struct ctx = { .i = 0; }
+ * bpf_loop(100, cb, &ctx, 0);
+ *
+ * This is similar to what is done in process_iter_next_call() for open
+ * coded iterators.
+ */
+ prev_st = in_callback_fn ? find_prev_entry(env, state, *insn_idx) : NULL;
+ if (prev_st) {
+ err = widen_imprecise_scalars(env, prev_st, state);
+ if (err)
+ return err;
+ }
+ return 0;
+}
+
+static void do_refine_retval_range(struct bpf_reg_state *regs, int ret_type,
+ int func_id,
+ struct bpf_call_arg_meta *meta)
+{
+ struct bpf_reg_state *ret_reg = &regs[BPF_REG_0];
+
+ if (ret_type != RET_INTEGER)
+ return;
+
+ switch (func_id) {
+ case BPF_FUNC_get_stack:
+ case BPF_FUNC_get_task_stack:
+ case BPF_FUNC_probe_read_str:
+ case BPF_FUNC_probe_read_kernel_str:
+ case BPF_FUNC_probe_read_user_str:
+ ret_reg->smax_value = meta->msize_max_value;
+ ret_reg->s32_max_value = meta->msize_max_value;
+ ret_reg->smin_value = -MAX_ERRNO;
+ ret_reg->s32_min_value = -MAX_ERRNO;
+ reg_bounds_sync(ret_reg);
+ break;
+ case BPF_FUNC_get_smp_processor_id:
+ ret_reg->umax_value = nr_cpu_ids - 1;
+ ret_reg->u32_max_value = nr_cpu_ids - 1;
+ ret_reg->smax_value = nr_cpu_ids - 1;
+ ret_reg->s32_max_value = nr_cpu_ids - 1;
+ ret_reg->umin_value = 0;
+ ret_reg->u32_min_value = 0;
+ ret_reg->smin_value = 0;
+ ret_reg->s32_min_value = 0;
+ reg_bounds_sync(ret_reg);
+ break;
+ }
+}
+
+static int
+record_func_map(struct bpf_verifier_env *env, struct bpf_call_arg_meta *meta,
+ int func_id, int insn_idx)
+{
+ struct bpf_insn_aux_data *aux = &env->insn_aux_data[insn_idx];
+ struct bpf_map *map = meta->map_ptr;
+
+ if (func_id != BPF_FUNC_tail_call &&
+ func_id != BPF_FUNC_map_lookup_elem &&
+ func_id != BPF_FUNC_map_update_elem &&
+ func_id != BPF_FUNC_map_delete_elem &&
+ func_id != BPF_FUNC_map_push_elem &&
+ func_id != BPF_FUNC_map_pop_elem &&
+ func_id != BPF_FUNC_map_peek_elem &&
+ func_id != BPF_FUNC_for_each_map_elem &&
+ func_id != BPF_FUNC_redirect_map &&
+ func_id != BPF_FUNC_map_lookup_percpu_elem)
+ return 0;
+
+ if (map == NULL) {
+ verbose(env, "kernel subsystem misconfigured verifier\n");
+ return -EINVAL;
+ }
+
+ /* In case of read-only, some additional restrictions
+ * need to be applied in order to prevent altering the
+ * state of the map from program side.
+ */
+ if ((map->map_flags & BPF_F_RDONLY_PROG) &&
+ (func_id == BPF_FUNC_map_delete_elem ||
+ func_id == BPF_FUNC_map_update_elem ||
+ func_id == BPF_FUNC_map_push_elem ||
+ func_id == BPF_FUNC_map_pop_elem)) {
+ verbose(env, "write into map forbidden\n");
+ return -EACCES;
+ }
+
+ if (!BPF_MAP_PTR(aux->map_ptr_state))
+ bpf_map_ptr_store(aux, meta->map_ptr,
+ !meta->map_ptr->bypass_spec_v1);
+ else if (BPF_MAP_PTR(aux->map_ptr_state) != meta->map_ptr)
+ bpf_map_ptr_store(aux, BPF_MAP_PTR_POISON,
+ !meta->map_ptr->bypass_spec_v1);
+ return 0;
+}
+
+static int
+record_func_key(struct bpf_verifier_env *env, struct bpf_call_arg_meta *meta,
+ int func_id, int insn_idx)
+{
+ struct bpf_insn_aux_data *aux = &env->insn_aux_data[insn_idx];
+ struct bpf_reg_state *regs = cur_regs(env), *reg;
+ struct bpf_map *map = meta->map_ptr;
+ u64 val, max;
+ int err;
+
+ if (func_id != BPF_FUNC_tail_call)
+ return 0;
+ if (!map || map->map_type != BPF_MAP_TYPE_PROG_ARRAY) {
+ verbose(env, "kernel subsystem misconfigured verifier\n");
+ return -EINVAL;
+ }
+
+ reg = &regs[BPF_REG_3];
+ val = reg->var_off.value;
+ max = map->max_entries;
+
+ if (!(register_is_const(reg) && val < max)) {
+ bpf_map_key_store(aux, BPF_MAP_KEY_POISON);
+ return 0;
+ }
+
+ err = mark_chain_precision(env, BPF_REG_3);
+ if (err)
+ return err;
+ if (bpf_map_key_unseen(aux))
+ bpf_map_key_store(aux, val);
+ else if (!bpf_map_key_poisoned(aux) &&
+ bpf_map_key_immediate(aux) != val)
+ bpf_map_key_store(aux, BPF_MAP_KEY_POISON);
+ return 0;
+}
+
+static int check_reference_leak(struct bpf_verifier_env *env)
+{
+ struct bpf_func_state *state = cur_func(env);
+ bool refs_lingering = false;
+ int i;
+
+ if (state->frameno && !state->in_callback_fn)
+ return 0;
+
+ for (i = 0; i < state->acquired_refs; i++) {
+ if (state->in_callback_fn && state->refs[i].callback_ref != state->frameno)
+ continue;
+ verbose(env, "Unreleased reference id=%d alloc_insn=%d\n",
+ state->refs[i].id, state->refs[i].insn_idx);
+ refs_lingering = true;
+ }
+ return refs_lingering ? -EINVAL : 0;
+}
+
+static int check_bpf_snprintf_call(struct bpf_verifier_env *env,
+ struct bpf_reg_state *regs)
+{
+ struct bpf_reg_state *fmt_reg = &regs[BPF_REG_3];
+ struct bpf_reg_state *data_len_reg = &regs[BPF_REG_5];
+ struct bpf_map *fmt_map = fmt_reg->map_ptr;
+ struct bpf_bprintf_data data = {};
+ int err, fmt_map_off, num_args;
+ u64 fmt_addr;
+ char *fmt;
+
+ /* data must be an array of u64 */
+ if (data_len_reg->var_off.value % 8)
+ return -EINVAL;
+ num_args = data_len_reg->var_off.value / 8;
+
+ /* fmt being ARG_PTR_TO_CONST_STR guarantees that var_off is const
+ * and map_direct_value_addr is set.
+ */
+ fmt_map_off = fmt_reg->off + fmt_reg->var_off.value;
+ err = fmt_map->ops->map_direct_value_addr(fmt_map, &fmt_addr,
+ fmt_map_off);
+ if (err) {
+ verbose(env, "verifier bug\n");
+ return -EFAULT;
+ }
+ fmt = (char *)(long)fmt_addr + fmt_map_off;
+
+ /* We are also guaranteed that fmt+fmt_map_off is NULL terminated, we
+ * can focus on validating the format specifiers.
+ */
+ err = bpf_bprintf_prepare(fmt, UINT_MAX, NULL, num_args, &data);
+ if (err < 0)
+ verbose(env, "Invalid format string\n");
+
+ return err;
+}
+
+static int check_get_func_ip(struct bpf_verifier_env *env)
+{
+ enum bpf_prog_type type = resolve_prog_type(env->prog);
+ int func_id = BPF_FUNC_get_func_ip;
+
+ if (type == BPF_PROG_TYPE_TRACING) {
+ if (!bpf_prog_has_trampoline(env->prog)) {
+ verbose(env, "func %s#%d supported only for fentry/fexit/fmod_ret programs\n",
+ func_id_name(func_id), func_id);
+ return -ENOTSUPP;
+ }
+ return 0;
+ } else if (type == BPF_PROG_TYPE_KPROBE) {
+ return 0;
+ }
+
+ verbose(env, "func %s#%d not supported for program type %d\n",
+ func_id_name(func_id), func_id, type);
+ return -ENOTSUPP;
+}
+
+static struct bpf_insn_aux_data *cur_aux(struct bpf_verifier_env *env)
+{
+ return &env->insn_aux_data[env->insn_idx];
+}
+
+static bool loop_flag_is_zero(struct bpf_verifier_env *env)
+{
+ struct bpf_reg_state *regs = cur_regs(env);
+ struct bpf_reg_state *reg = &regs[BPF_REG_4];
+ bool reg_is_null = register_is_null(reg);
+
+ if (reg_is_null)
+ mark_chain_precision(env, BPF_REG_4);
+
+ return reg_is_null;
+}
+
+static void update_loop_inline_state(struct bpf_verifier_env *env, u32 subprogno)
+{
+ struct bpf_loop_inline_state *state = &cur_aux(env)->loop_inline_state;
+
+ if (!state->initialized) {
+ state->initialized = 1;
+ state->fit_for_inline = loop_flag_is_zero(env);
+ state->callback_subprogno = subprogno;
+ return;
+ }
+
+ if (!state->fit_for_inline)
+ return;
+
+ state->fit_for_inline = (loop_flag_is_zero(env) &&
+ state->callback_subprogno == subprogno);
+}
+
+static int check_helper_call(struct bpf_verifier_env *env, struct bpf_insn *insn,
+ int *insn_idx_p)
+{
+ enum bpf_prog_type prog_type = resolve_prog_type(env->prog);
+ const struct bpf_func_proto *fn = NULL;
+ enum bpf_return_type ret_type;
+ enum bpf_type_flag ret_flag;
+ struct bpf_reg_state *regs;
+ struct bpf_call_arg_meta meta;
+ int insn_idx = *insn_idx_p;
+ bool changes_data;
+ int i, err, func_id;
+
+ /* find function prototype */
+ func_id = insn->imm;
+ if (func_id < 0 || func_id >= __BPF_FUNC_MAX_ID) {
+ verbose(env, "invalid func %s#%d\n", func_id_name(func_id),
+ func_id);
+ return -EINVAL;
+ }
+
+ if (env->ops->get_func_proto)
+ fn = env->ops->get_func_proto(func_id, env->prog);
+ if (!fn) {
+ verbose(env, "unknown func %s#%d\n", func_id_name(func_id),
+ func_id);
+ return -EINVAL;
+ }
+
+ /* eBPF programs must be GPL compatible to use GPL-ed functions */
+ if (!env->prog->gpl_compatible && fn->gpl_only) {
+ verbose(env, "cannot call GPL-restricted function from non-GPL compatible program\n");
+ return -EINVAL;
+ }
+
+ if (fn->allowed && !fn->allowed(env->prog)) {
+ verbose(env, "helper call is not allowed in probe\n");
+ return -EINVAL;
+ }
+
+ if (!env->prog->aux->sleepable && fn->might_sleep) {
+ verbose(env, "helper call might sleep in a non-sleepable prog\n");
+ return -EINVAL;
+ }
+
+ /* With LD_ABS/IND some JITs save/restore skb from r1. */
+ changes_data = bpf_helper_changes_pkt_data(fn->func);
+ if (changes_data && fn->arg1_type != ARG_PTR_TO_CTX) {
+ verbose(env, "kernel subsystem misconfigured func %s#%d: r1 != ctx\n",
+ func_id_name(func_id), func_id);
+ return -EINVAL;
+ }
+
+ memset(&meta, 0, sizeof(meta));
+ meta.pkt_access = fn->pkt_access;
+
+ err = check_func_proto(fn, func_id);
+ if (err) {
+ verbose(env, "kernel subsystem misconfigured func %s#%d\n",
+ func_id_name(func_id), func_id);
+ return err;
+ }
+
+ if (env->cur_state->active_rcu_lock) {
+ if (fn->might_sleep) {
+ verbose(env, "sleepable helper %s#%d in rcu_read_lock region\n",
+ func_id_name(func_id), func_id);
+ return -EINVAL;
+ }
+
+ if (env->prog->aux->sleepable && is_storage_get_function(func_id))
+ env->insn_aux_data[insn_idx].storage_get_func_atomic = true;
+ }
+
+ meta.func_id = func_id;
+ /* check args */
+ for (i = 0; i < MAX_BPF_FUNC_REG_ARGS; i++) {
+ err = check_func_arg(env, i, &meta, fn, insn_idx);
+ if (err)
+ return err;
+ }
+
+ err = record_func_map(env, &meta, func_id, insn_idx);
+ if (err)
+ return err;
+
+ err = record_func_key(env, &meta, func_id, insn_idx);
+ if (err)
+ return err;
+
+ /* Mark slots with STACK_MISC in case of raw mode, stack offset
+ * is inferred from register state.
+ */
+ for (i = 0; i < meta.access_size; i++) {
+ err = check_mem_access(env, insn_idx, meta.regno, i, BPF_B,
+ BPF_WRITE, -1, false, false);
+ if (err)
+ return err;
+ }
+
+ regs = cur_regs(env);
+
+ if (meta.release_regno) {
+ err = -EINVAL;
+ /* This can only be set for PTR_TO_STACK, as CONST_PTR_TO_DYNPTR cannot
+ * be released by any dynptr helper. Hence, unmark_stack_slots_dynptr
+ * is safe to do directly.
+ */
+ if (arg_type_is_dynptr(fn->arg_type[meta.release_regno - BPF_REG_1])) {
+ if (regs[meta.release_regno].type == CONST_PTR_TO_DYNPTR) {
+ verbose(env, "verifier internal error: CONST_PTR_TO_DYNPTR cannot be released\n");
+ return -EFAULT;
+ }
+ err = unmark_stack_slots_dynptr(env, &regs[meta.release_regno]);
+ } else if (meta.ref_obj_id) {
+ err = release_reference(env, meta.ref_obj_id);
+ } else if (register_is_null(&regs[meta.release_regno])) {
+ /* meta.ref_obj_id can only be 0 if register that is meant to be
+ * released is NULL, which must be > R0.
+ */
+ err = 0;
+ }
+ if (err) {
+ verbose(env, "func %s#%d reference has not been acquired before\n",
+ func_id_name(func_id), func_id);
+ return err;
+ }
+ }
+
+ switch (func_id) {
+ case BPF_FUNC_tail_call:
+ err = check_reference_leak(env);
+ if (err) {
+ verbose(env, "tail_call would lead to reference leak\n");
+ return err;
+ }
+ break;
+ case BPF_FUNC_get_local_storage:
+ /* check that flags argument in get_local_storage(map, flags) is 0,
+ * this is required because get_local_storage() can't return an error.
+ */
+ if (!register_is_null(&regs[BPF_REG_2])) {
+ verbose(env, "get_local_storage() doesn't support non-zero flags\n");
+ return -EINVAL;
+ }
+ break;
+ case BPF_FUNC_for_each_map_elem:
+ err = push_callback_call(env, insn, insn_idx, meta.subprogno,
+ set_map_elem_callback_state);
+ break;
+ case BPF_FUNC_timer_set_callback:
+ err = push_callback_call(env, insn, insn_idx, meta.subprogno,
+ set_timer_callback_state);
+ break;
+ case BPF_FUNC_find_vma:
+ err = push_callback_call(env, insn, insn_idx, meta.subprogno,
+ set_find_vma_callback_state);
+ break;
+ case BPF_FUNC_snprintf:
+ err = check_bpf_snprintf_call(env, regs);
+ break;
+ case BPF_FUNC_loop:
+ update_loop_inline_state(env, meta.subprogno);
+ /* Verifier relies on R1 value to determine if bpf_loop() iteration
+ * is finished, thus mark it precise.
+ */
+ err = mark_chain_precision(env, BPF_REG_1);
+ if (err)
+ return err;
+ if (cur_func(env)->callback_depth < regs[BPF_REG_1].umax_value) {
+ err = push_callback_call(env, insn, insn_idx, meta.subprogno,
+ set_loop_callback_state);
+ } else {
+ cur_func(env)->callback_depth = 0;
+ if (env->log.level & BPF_LOG_LEVEL2)
+ verbose(env, "frame%d bpf_loop iteration limit reached\n",
+ env->cur_state->curframe);
+ }
+ break;
+ case BPF_FUNC_dynptr_from_mem:
+ if (regs[BPF_REG_1].type != PTR_TO_MAP_VALUE) {
+ verbose(env, "Unsupported reg type %s for bpf_dynptr_from_mem data\n",
+ reg_type_str(env, regs[BPF_REG_1].type));
+ return -EACCES;
+ }
+ break;
+ case BPF_FUNC_set_retval:
+ if (prog_type == BPF_PROG_TYPE_LSM &&
+ env->prog->expected_attach_type == BPF_LSM_CGROUP) {
+ if (!env->prog->aux->attach_func_proto->type) {
+ /* Make sure programs that attach to void
+ * hooks don't try to modify return value.
+ */
+ verbose(env, "BPF_LSM_CGROUP that attach to void LSM hooks can't modify return value!\n");
+ return -EINVAL;
+ }
+ }
+ break;
+ case BPF_FUNC_dynptr_data:
+ {
+ struct bpf_reg_state *reg;
+ int id, ref_obj_id;
+
+ reg = get_dynptr_arg_reg(env, fn, regs);
+ if (!reg)
+ return -EFAULT;
+
+
+ if (meta.dynptr_id) {
+ verbose(env, "verifier internal error: meta.dynptr_id already set\n");
+ return -EFAULT;
+ }
+ if (meta.ref_obj_id) {
+ verbose(env, "verifier internal error: meta.ref_obj_id already set\n");
+ return -EFAULT;
+ }
+
+ id = dynptr_id(env, reg);
+ if (id < 0) {
+ verbose(env, "verifier internal error: failed to obtain dynptr id\n");
+ return id;
+ }
+
+ ref_obj_id = dynptr_ref_obj_id(env, reg);
+ if (ref_obj_id < 0) {
+ verbose(env, "verifier internal error: failed to obtain dynptr ref_obj_id\n");
+ return ref_obj_id;
+ }
+
+ meta.dynptr_id = id;
+ meta.ref_obj_id = ref_obj_id;
+
+ break;
+ }
+ case BPF_FUNC_dynptr_write:
+ {
+ enum bpf_dynptr_type dynptr_type;
+ struct bpf_reg_state *reg;
+
+ reg = get_dynptr_arg_reg(env, fn, regs);
+ if (!reg)
+ return -EFAULT;
+
+ dynptr_type = dynptr_get_type(env, reg);
+ if (dynptr_type == BPF_DYNPTR_TYPE_INVALID)
+ return -EFAULT;
+
+ if (dynptr_type == BPF_DYNPTR_TYPE_SKB)
+ /* this will trigger clear_all_pkt_pointers(), which will
+ * invalidate all dynptr slices associated with the skb
+ */
+ changes_data = true;
+
+ break;
+ }
+ case BPF_FUNC_user_ringbuf_drain:
+ err = push_callback_call(env, insn, insn_idx, meta.subprogno,
+ set_user_ringbuf_callback_state);
+ break;
+ }
+
+ if (err)
+ return err;
+
+ /* reset caller saved regs */
+ for (i = 0; i < CALLER_SAVED_REGS; i++) {
+ mark_reg_not_init(env, regs, caller_saved[i]);
+ check_reg_arg(env, caller_saved[i], DST_OP_NO_MARK);
+ }
+
+ /* helper call returns 64-bit value. */
+ regs[BPF_REG_0].subreg_def = DEF_NOT_SUBREG;
+
+ /* update return register (already marked as written above) */
+ ret_type = fn->ret_type;
+ ret_flag = type_flag(ret_type);
+
+ switch (base_type(ret_type)) {
+ case RET_INTEGER:
+ /* sets type to SCALAR_VALUE */
+ mark_reg_unknown(env, regs, BPF_REG_0);
+ break;
+ case RET_VOID:
+ regs[BPF_REG_0].type = NOT_INIT;
+ break;
+ case RET_PTR_TO_MAP_VALUE:
+ /* There is no offset yet applied, variable or fixed */
+ mark_reg_known_zero(env, regs, BPF_REG_0);
+ /* remember map_ptr, so that check_map_access()
+ * can check 'value_size' boundary of memory access
+ * to map element returned from bpf_map_lookup_elem()
+ */
+ if (meta.map_ptr == NULL) {
+ verbose(env,
+ "kernel subsystem misconfigured verifier\n");
+ return -EINVAL;
+ }
+ regs[BPF_REG_0].map_ptr = meta.map_ptr;
+ regs[BPF_REG_0].map_uid = meta.map_uid;
+ regs[BPF_REG_0].type = PTR_TO_MAP_VALUE | ret_flag;
+ if (!type_may_be_null(ret_type) &&
+ btf_record_has_field(meta.map_ptr->record, BPF_SPIN_LOCK)) {
+ regs[BPF_REG_0].id = ++env->id_gen;
+ }
+ break;
+ case RET_PTR_TO_SOCKET:
+ mark_reg_known_zero(env, regs, BPF_REG_0);
+ regs[BPF_REG_0].type = PTR_TO_SOCKET | ret_flag;
+ break;
+ case RET_PTR_TO_SOCK_COMMON:
+ mark_reg_known_zero(env, regs, BPF_REG_0);
+ regs[BPF_REG_0].type = PTR_TO_SOCK_COMMON | ret_flag;
+ break;
+ case RET_PTR_TO_TCP_SOCK:
+ mark_reg_known_zero(env, regs, BPF_REG_0);
+ regs[BPF_REG_0].type = PTR_TO_TCP_SOCK | ret_flag;
+ break;
+ case RET_PTR_TO_MEM:
+ mark_reg_known_zero(env, regs, BPF_REG_0);
+ regs[BPF_REG_0].type = PTR_TO_MEM | ret_flag;
+ regs[BPF_REG_0].mem_size = meta.mem_size;
+ break;
+ case RET_PTR_TO_MEM_OR_BTF_ID:
+ {
+ const struct btf_type *t;
+
+ mark_reg_known_zero(env, regs, BPF_REG_0);
+ t = btf_type_skip_modifiers(meta.ret_btf, meta.ret_btf_id, NULL);
+ if (!btf_type_is_struct(t)) {
+ u32 tsize;
+ const struct btf_type *ret;
+ const char *tname;
+
+ /* resolve the type size of ksym. */
+ ret = btf_resolve_size(meta.ret_btf, t, &tsize);
+ if (IS_ERR(ret)) {
+ tname = btf_name_by_offset(meta.ret_btf, t->name_off);
+ verbose(env, "unable to resolve the size of type '%s': %ld\n",
+ tname, PTR_ERR(ret));
+ return -EINVAL;
+ }
+ regs[BPF_REG_0].type = PTR_TO_MEM | ret_flag;
+ regs[BPF_REG_0].mem_size = tsize;
+ } else {
+ /* MEM_RDONLY may be carried from ret_flag, but it
+ * doesn't apply on PTR_TO_BTF_ID. Fold it, otherwise
+ * it will confuse the check of PTR_TO_BTF_ID in
+ * check_mem_access().
+ */
+ ret_flag &= ~MEM_RDONLY;
+
+ regs[BPF_REG_0].type = PTR_TO_BTF_ID | ret_flag;
+ regs[BPF_REG_0].btf = meta.ret_btf;
+ regs[BPF_REG_0].btf_id = meta.ret_btf_id;
+ }
+ break;
+ }
+ case RET_PTR_TO_BTF_ID:
+ {
+ struct btf *ret_btf;
+ int ret_btf_id;
+
+ mark_reg_known_zero(env, regs, BPF_REG_0);
+ regs[BPF_REG_0].type = PTR_TO_BTF_ID | ret_flag;
+ if (func_id == BPF_FUNC_kptr_xchg) {
+ ret_btf = meta.kptr_field->kptr.btf;
+ ret_btf_id = meta.kptr_field->kptr.btf_id;
+ if (!btf_is_kernel(ret_btf))
+ regs[BPF_REG_0].type |= MEM_ALLOC;
+ } else {
+ if (fn->ret_btf_id == BPF_PTR_POISON) {
+ verbose(env, "verifier internal error:");
+ verbose(env, "func %s has non-overwritten BPF_PTR_POISON return type\n",
+ func_id_name(func_id));
+ return -EINVAL;
+ }
+ ret_btf = btf_vmlinux;
+ ret_btf_id = *fn->ret_btf_id;
+ }
+ if (ret_btf_id == 0) {
+ verbose(env, "invalid return type %u of func %s#%d\n",
+ base_type(ret_type), func_id_name(func_id),
+ func_id);
+ return -EINVAL;
+ }
+ regs[BPF_REG_0].btf = ret_btf;
+ regs[BPF_REG_0].btf_id = ret_btf_id;
+ break;
+ }
+ default:
+ verbose(env, "unknown return type %u of func %s#%d\n",
+ base_type(ret_type), func_id_name(func_id), func_id);
+ return -EINVAL;
+ }
+
+ if (type_may_be_null(regs[BPF_REG_0].type))
+ regs[BPF_REG_0].id = ++env->id_gen;
+
+ if (helper_multiple_ref_obj_use(func_id, meta.map_ptr)) {
+ verbose(env, "verifier internal error: func %s#%d sets ref_obj_id more than once\n",
+ func_id_name(func_id), func_id);
+ return -EFAULT;
+ }
+
+ if (is_dynptr_ref_function(func_id))
+ regs[BPF_REG_0].dynptr_id = meta.dynptr_id;
+
+ if (is_ptr_cast_function(func_id) || is_dynptr_ref_function(func_id)) {
+ /* For release_reference() */
+ regs[BPF_REG_0].ref_obj_id = meta.ref_obj_id;
+ } else if (is_acquire_function(func_id, meta.map_ptr)) {
+ int id = acquire_reference_state(env, insn_idx);
+
+ if (id < 0)
+ return id;
+ /* For mark_ptr_or_null_reg() */
+ regs[BPF_REG_0].id = id;
+ /* For release_reference() */
+ regs[BPF_REG_0].ref_obj_id = id;
+ }
+
+ do_refine_retval_range(regs, fn->ret_type, func_id, &meta);
+
+ err = check_map_func_compatibility(env, meta.map_ptr, func_id);
+ if (err)
+ return err;
+
+ if ((func_id == BPF_FUNC_get_stack ||
+ func_id == BPF_FUNC_get_task_stack) &&
+ !env->prog->has_callchain_buf) {
+ const char *err_str;
+
+#ifdef CONFIG_PERF_EVENTS
+ err = get_callchain_buffers(sysctl_perf_event_max_stack);
+ err_str = "cannot get callchain buffer for func %s#%d\n";
+#else
+ err = -ENOTSUPP;
+ err_str = "func %s#%d not supported without CONFIG_PERF_EVENTS\n";
+#endif
+ if (err) {
+ verbose(env, err_str, func_id_name(func_id), func_id);
+ return err;
+ }
+
+ env->prog->has_callchain_buf = true;
+ }
+
+ if (func_id == BPF_FUNC_get_stackid || func_id == BPF_FUNC_get_stack)
+ env->prog->call_get_stack = true;
+
+ if (func_id == BPF_FUNC_get_func_ip) {
+ if (check_get_func_ip(env))
+ return -ENOTSUPP;
+ env->prog->call_get_func_ip = true;
+ }
+
+ if (changes_data)
+ clear_all_pkt_pointers(env);
+ return 0;
+}
+
+/* mark_btf_func_reg_size() is used when the reg size is determined by
+ * the BTF func_proto's return value size and argument.
+ */
+static void mark_btf_func_reg_size(struct bpf_verifier_env *env, u32 regno,
+ size_t reg_size)
+{
+ struct bpf_reg_state *reg = &cur_regs(env)[regno];
+
+ if (regno == BPF_REG_0) {
+ /* Function return value */
+ reg->live |= REG_LIVE_WRITTEN;
+ reg->subreg_def = reg_size == sizeof(u64) ?
+ DEF_NOT_SUBREG : env->insn_idx + 1;
+ } else {
+ /* Function argument */
+ if (reg_size == sizeof(u64)) {
+ mark_insn_zext(env, reg);
+ mark_reg_read(env, reg, reg->parent, REG_LIVE_READ64);
+ } else {
+ mark_reg_read(env, reg, reg->parent, REG_LIVE_READ32);
+ }
+ }
+}
+
+static bool is_kfunc_acquire(struct bpf_kfunc_call_arg_meta *meta)
+{
+ return meta->kfunc_flags & KF_ACQUIRE;
+}
+
+static bool is_kfunc_release(struct bpf_kfunc_call_arg_meta *meta)
+{
+ return meta->kfunc_flags & KF_RELEASE;
+}
+
+static bool is_kfunc_trusted_args(struct bpf_kfunc_call_arg_meta *meta)
+{
+ return (meta->kfunc_flags & KF_TRUSTED_ARGS) || is_kfunc_release(meta);
+}
+
+static bool is_kfunc_sleepable(struct bpf_kfunc_call_arg_meta *meta)
+{
+ return meta->kfunc_flags & KF_SLEEPABLE;
+}
+
+static bool is_kfunc_destructive(struct bpf_kfunc_call_arg_meta *meta)
+{
+ return meta->kfunc_flags & KF_DESTRUCTIVE;
+}
+
+static bool is_kfunc_rcu(struct bpf_kfunc_call_arg_meta *meta)
+{
+ return meta->kfunc_flags & KF_RCU;
+}
+
+static bool __kfunc_param_match_suffix(const struct btf *btf,
+ const struct btf_param *arg,
+ const char *suffix)
+{
+ int suffix_len = strlen(suffix), len;
+ const char *param_name;
+
+ /* In the future, this can be ported to use BTF tagging */
+ param_name = btf_name_by_offset(btf, arg->name_off);
+ if (str_is_empty(param_name))
+ return false;
+ len = strlen(param_name);
+ if (len < suffix_len)
+ return false;
+ param_name += len - suffix_len;
+ return !strncmp(param_name, suffix, suffix_len);
+}
+
+static bool is_kfunc_arg_mem_size(const struct btf *btf,
+ const struct btf_param *arg,
+ const struct bpf_reg_state *reg)
+{
+ const struct btf_type *t;
+
+ t = btf_type_skip_modifiers(btf, arg->type, NULL);
+ if (!btf_type_is_scalar(t) || reg->type != SCALAR_VALUE)
+ return false;
+
+ return __kfunc_param_match_suffix(btf, arg, "__sz");
+}
+
+static bool is_kfunc_arg_const_mem_size(const struct btf *btf,
+ const struct btf_param *arg,
+ const struct bpf_reg_state *reg)
+{
+ const struct btf_type *t;
+
+ t = btf_type_skip_modifiers(btf, arg->type, NULL);
+ if (!btf_type_is_scalar(t) || reg->type != SCALAR_VALUE)
+ return false;
+
+ return __kfunc_param_match_suffix(btf, arg, "__szk");
+}
+
+static bool is_kfunc_arg_optional(const struct btf *btf, const struct btf_param *arg)
+{
+ return __kfunc_param_match_suffix(btf, arg, "__opt");
+}
+
+static bool is_kfunc_arg_constant(const struct btf *btf, const struct btf_param *arg)
+{
+ return __kfunc_param_match_suffix(btf, arg, "__k");
+}
+
+static bool is_kfunc_arg_ignore(const struct btf *btf, const struct btf_param *arg)
+{
+ return __kfunc_param_match_suffix(btf, arg, "__ign");
+}
+
+static bool is_kfunc_arg_alloc_obj(const struct btf *btf, const struct btf_param *arg)
+{
+ return __kfunc_param_match_suffix(btf, arg, "__alloc");
+}
+
+static bool is_kfunc_arg_uninit(const struct btf *btf, const struct btf_param *arg)
+{
+ return __kfunc_param_match_suffix(btf, arg, "__uninit");
+}
+
+static bool is_kfunc_arg_refcounted_kptr(const struct btf *btf, const struct btf_param *arg)
+{
+ return __kfunc_param_match_suffix(btf, arg, "__refcounted_kptr");
+}
+
+static bool is_kfunc_arg_scalar_with_name(const struct btf *btf,
+ const struct btf_param *arg,
+ const char *name)
+{
+ int len, target_len = strlen(name);
+ const char *param_name;
+
+ param_name = btf_name_by_offset(btf, arg->name_off);
+ if (str_is_empty(param_name))
+ return false;
+ len = strlen(param_name);
+ if (len != target_len)
+ return false;
+ if (strcmp(param_name, name))
+ return false;
+
+ return true;
+}
+
+enum {
+ KF_ARG_DYNPTR_ID,
+ KF_ARG_LIST_HEAD_ID,
+ KF_ARG_LIST_NODE_ID,
+ KF_ARG_RB_ROOT_ID,
+ KF_ARG_RB_NODE_ID,
+};
+
+BTF_ID_LIST(kf_arg_btf_ids)
+BTF_ID(struct, bpf_dynptr_kern)
+BTF_ID(struct, bpf_list_head)
+BTF_ID(struct, bpf_list_node)
+BTF_ID(struct, bpf_rb_root)
+BTF_ID(struct, bpf_rb_node)
+
+static bool __is_kfunc_ptr_arg_type(const struct btf *btf,
+ const struct btf_param *arg, int type)
+{
+ const struct btf_type *t;
+ u32 res_id;
+
+ t = btf_type_skip_modifiers(btf, arg->type, NULL);
+ if (!t)
+ return false;
+ if (!btf_type_is_ptr(t))
+ return false;
+ t = btf_type_skip_modifiers(btf, t->type, &res_id);
+ if (!t)
+ return false;
+ return btf_types_are_same(btf, res_id, btf_vmlinux, kf_arg_btf_ids[type]);
+}
+
+static bool is_kfunc_arg_dynptr(const struct btf *btf, const struct btf_param *arg)
+{
+ return __is_kfunc_ptr_arg_type(btf, arg, KF_ARG_DYNPTR_ID);
+}
+
+static bool is_kfunc_arg_list_head(const struct btf *btf, const struct btf_param *arg)
+{
+ return __is_kfunc_ptr_arg_type(btf, arg, KF_ARG_LIST_HEAD_ID);
+}
+
+static bool is_kfunc_arg_list_node(const struct btf *btf, const struct btf_param *arg)
+{
+ return __is_kfunc_ptr_arg_type(btf, arg, KF_ARG_LIST_NODE_ID);
+}
+
+static bool is_kfunc_arg_rbtree_root(const struct btf *btf, const struct btf_param *arg)
+{
+ return __is_kfunc_ptr_arg_type(btf, arg, KF_ARG_RB_ROOT_ID);
+}
+
+static bool is_kfunc_arg_rbtree_node(const struct btf *btf, const struct btf_param *arg)
+{
+ return __is_kfunc_ptr_arg_type(btf, arg, KF_ARG_RB_NODE_ID);
+}
+
+static bool is_kfunc_arg_callback(struct bpf_verifier_env *env, const struct btf *btf,
+ const struct btf_param *arg)
+{
+ const struct btf_type *t;
+
+ t = btf_type_resolve_func_ptr(btf, arg->type, NULL);
+ if (!t)
+ return false;
+
+ return true;
+}
+
+/* Returns true if struct is composed of scalars, 4 levels of nesting allowed */
+static bool __btf_type_is_scalar_struct(struct bpf_verifier_env *env,
+ const struct btf *btf,
+ const struct btf_type *t, int rec)
+{
+ const struct btf_type *member_type;
+ const struct btf_member *member;
+ u32 i;
+
+ if (!btf_type_is_struct(t))
+ return false;
+
+ for_each_member(i, t, member) {
+ const struct btf_array *array;
+
+ member_type = btf_type_skip_modifiers(btf, member->type, NULL);
+ if (btf_type_is_struct(member_type)) {
+ if (rec >= 3) {
+ verbose(env, "max struct nesting depth exceeded\n");
+ return false;
+ }
+ if (!__btf_type_is_scalar_struct(env, btf, member_type, rec + 1))
+ return false;
+ continue;
+ }
+ if (btf_type_is_array(member_type)) {
+ array = btf_array(member_type);
+ if (!array->nelems)
+ return false;
+ member_type = btf_type_skip_modifiers(btf, array->type, NULL);
+ if (!btf_type_is_scalar(member_type))
+ return false;
+ continue;
+ }
+ if (!btf_type_is_scalar(member_type))
+ return false;
+ }
+ return true;
+}
+
+enum kfunc_ptr_arg_type {
+ KF_ARG_PTR_TO_CTX,
+ KF_ARG_PTR_TO_ALLOC_BTF_ID, /* Allocated object */
+ KF_ARG_PTR_TO_REFCOUNTED_KPTR, /* Refcounted local kptr */
+ KF_ARG_PTR_TO_DYNPTR,
+ KF_ARG_PTR_TO_ITER,
+ KF_ARG_PTR_TO_LIST_HEAD,
+ KF_ARG_PTR_TO_LIST_NODE,
+ KF_ARG_PTR_TO_BTF_ID, /* Also covers reg2btf_ids conversions */
+ KF_ARG_PTR_TO_MEM,
+ KF_ARG_PTR_TO_MEM_SIZE, /* Size derived from next argument, skip it */
+ KF_ARG_PTR_TO_CALLBACK,
+ KF_ARG_PTR_TO_RB_ROOT,
+ KF_ARG_PTR_TO_RB_NODE,
+};
+
+enum special_kfunc_type {
+ KF_bpf_obj_new_impl,
+ KF_bpf_obj_drop_impl,
+ KF_bpf_refcount_acquire_impl,
+ KF_bpf_list_push_front_impl,
+ KF_bpf_list_push_back_impl,
+ KF_bpf_list_pop_front,
+ KF_bpf_list_pop_back,
+ KF_bpf_cast_to_kern_ctx,
+ KF_bpf_rdonly_cast,
+ KF_bpf_rcu_read_lock,
+ KF_bpf_rcu_read_unlock,
+ KF_bpf_rbtree_remove,
+ KF_bpf_rbtree_add_impl,
+ KF_bpf_rbtree_first,
+ KF_bpf_dynptr_from_skb,
+ KF_bpf_dynptr_from_xdp,
+ KF_bpf_dynptr_slice,
+ KF_bpf_dynptr_slice_rdwr,
+ KF_bpf_dynptr_clone,
+};
+
+BTF_SET_START(special_kfunc_set)
+BTF_ID(func, bpf_obj_new_impl)
+BTF_ID(func, bpf_obj_drop_impl)
+BTF_ID(func, bpf_refcount_acquire_impl)
+BTF_ID(func, bpf_list_push_front_impl)
+BTF_ID(func, bpf_list_push_back_impl)
+BTF_ID(func, bpf_list_pop_front)
+BTF_ID(func, bpf_list_pop_back)
+BTF_ID(func, bpf_cast_to_kern_ctx)
+BTF_ID(func, bpf_rdonly_cast)
+BTF_ID(func, bpf_rbtree_remove)
+BTF_ID(func, bpf_rbtree_add_impl)
+BTF_ID(func, bpf_rbtree_first)
+BTF_ID(func, bpf_dynptr_from_skb)
+BTF_ID(func, bpf_dynptr_from_xdp)
+BTF_ID(func, bpf_dynptr_slice)
+BTF_ID(func, bpf_dynptr_slice_rdwr)
+BTF_ID(func, bpf_dynptr_clone)
+BTF_SET_END(special_kfunc_set)
+
+BTF_ID_LIST(special_kfunc_list)
+BTF_ID(func, bpf_obj_new_impl)
+BTF_ID(func, bpf_obj_drop_impl)
+BTF_ID(func, bpf_refcount_acquire_impl)
+BTF_ID(func, bpf_list_push_front_impl)
+BTF_ID(func, bpf_list_push_back_impl)
+BTF_ID(func, bpf_list_pop_front)
+BTF_ID(func, bpf_list_pop_back)
+BTF_ID(func, bpf_cast_to_kern_ctx)
+BTF_ID(func, bpf_rdonly_cast)
+BTF_ID(func, bpf_rcu_read_lock)
+BTF_ID(func, bpf_rcu_read_unlock)
+BTF_ID(func, bpf_rbtree_remove)
+BTF_ID(func, bpf_rbtree_add_impl)
+BTF_ID(func, bpf_rbtree_first)
+BTF_ID(func, bpf_dynptr_from_skb)
+BTF_ID(func, bpf_dynptr_from_xdp)
+BTF_ID(func, bpf_dynptr_slice)
+BTF_ID(func, bpf_dynptr_slice_rdwr)
+BTF_ID(func, bpf_dynptr_clone)
+
+static bool is_kfunc_ret_null(struct bpf_kfunc_call_arg_meta *meta)
+{
+ if (meta->func_id == special_kfunc_list[KF_bpf_refcount_acquire_impl] &&
+ meta->arg_owning_ref) {
+ return false;
+ }
+
+ return meta->kfunc_flags & KF_RET_NULL;
+}
+
+static bool is_kfunc_bpf_rcu_read_lock(struct bpf_kfunc_call_arg_meta *meta)
+{
+ return meta->func_id == special_kfunc_list[KF_bpf_rcu_read_lock];
+}
+
+static bool is_kfunc_bpf_rcu_read_unlock(struct bpf_kfunc_call_arg_meta *meta)
+{
+ return meta->func_id == special_kfunc_list[KF_bpf_rcu_read_unlock];
+}
+
+static enum kfunc_ptr_arg_type
+get_kfunc_ptr_arg_type(struct bpf_verifier_env *env,
+ struct bpf_kfunc_call_arg_meta *meta,
+ const struct btf_type *t, const struct btf_type *ref_t,
+ const char *ref_tname, const struct btf_param *args,
+ int argno, int nargs)
+{
+ u32 regno = argno + 1;
+ struct bpf_reg_state *regs = cur_regs(env);
+ struct bpf_reg_state *reg = &regs[regno];
+ bool arg_mem_size = false;
+
+ if (meta->func_id == special_kfunc_list[KF_bpf_cast_to_kern_ctx])
+ return KF_ARG_PTR_TO_CTX;
+
+ /* In this function, we verify the kfunc's BTF as per the argument type,
+ * leaving the rest of the verification with respect to the register
+ * type to our caller. When a set of conditions hold in the BTF type of
+ * arguments, we resolve it to a known kfunc_ptr_arg_type.
+ */
+ if (btf_get_prog_ctx_type(&env->log, meta->btf, t, resolve_prog_type(env->prog), argno))
+ return KF_ARG_PTR_TO_CTX;
+
+ if (is_kfunc_arg_alloc_obj(meta->btf, &args[argno]))
+ return KF_ARG_PTR_TO_ALLOC_BTF_ID;
+
+ if (is_kfunc_arg_refcounted_kptr(meta->btf, &args[argno]))
+ return KF_ARG_PTR_TO_REFCOUNTED_KPTR;
+
+ if (is_kfunc_arg_dynptr(meta->btf, &args[argno]))
+ return KF_ARG_PTR_TO_DYNPTR;
+
+ if (is_kfunc_arg_iter(meta, argno))
+ return KF_ARG_PTR_TO_ITER;
+
+ if (is_kfunc_arg_list_head(meta->btf, &args[argno]))
+ return KF_ARG_PTR_TO_LIST_HEAD;
+
+ if (is_kfunc_arg_list_node(meta->btf, &args[argno]))
+ return KF_ARG_PTR_TO_LIST_NODE;
+
+ if (is_kfunc_arg_rbtree_root(meta->btf, &args[argno]))
+ return KF_ARG_PTR_TO_RB_ROOT;
+
+ if (is_kfunc_arg_rbtree_node(meta->btf, &args[argno]))
+ return KF_ARG_PTR_TO_RB_NODE;
+
+ if ((base_type(reg->type) == PTR_TO_BTF_ID || reg2btf_ids[base_type(reg->type)])) {
+ if (!btf_type_is_struct(ref_t)) {
+ verbose(env, "kernel function %s args#%d pointer type %s %s is not supported\n",
+ meta->func_name, argno, btf_type_str(ref_t), ref_tname);
+ return -EINVAL;
+ }
+ return KF_ARG_PTR_TO_BTF_ID;
+ }
+
+ if (is_kfunc_arg_callback(env, meta->btf, &args[argno]))
+ return KF_ARG_PTR_TO_CALLBACK;
+
+
+ if (argno + 1 < nargs &&
+ (is_kfunc_arg_mem_size(meta->btf, &args[argno + 1], &regs[regno + 1]) ||
+ is_kfunc_arg_const_mem_size(meta->btf, &args[argno + 1], &regs[regno + 1])))
+ arg_mem_size = true;
+
+ /* This is the catch all argument type of register types supported by
+ * check_helper_mem_access. However, we only allow when argument type is
+ * pointer to scalar, or struct composed (recursively) of scalars. When
+ * arg_mem_size is true, the pointer can be void *.
+ */
+ if (!btf_type_is_scalar(ref_t) && !__btf_type_is_scalar_struct(env, meta->btf, ref_t, 0) &&
+ (arg_mem_size ? !btf_type_is_void(ref_t) : 1)) {
+ verbose(env, "arg#%d pointer type %s %s must point to %sscalar, or struct with scalar\n",
+ argno, btf_type_str(ref_t), ref_tname, arg_mem_size ? "void, " : "");
+ return -EINVAL;
+ }
+ return arg_mem_size ? KF_ARG_PTR_TO_MEM_SIZE : KF_ARG_PTR_TO_MEM;
+}
+
+static int process_kf_arg_ptr_to_btf_id(struct bpf_verifier_env *env,
+ struct bpf_reg_state *reg,
+ const struct btf_type *ref_t,
+ const char *ref_tname, u32 ref_id,
+ struct bpf_kfunc_call_arg_meta *meta,
+ int argno)
+{
+ const struct btf_type *reg_ref_t;
+ bool strict_type_match = false;
+ const struct btf *reg_btf;
+ const char *reg_ref_tname;
+ u32 reg_ref_id;
+
+ if (base_type(reg->type) == PTR_TO_BTF_ID) {
+ reg_btf = reg->btf;
+ reg_ref_id = reg->btf_id;
+ } else {
+ reg_btf = btf_vmlinux;
+ reg_ref_id = *reg2btf_ids[base_type(reg->type)];
+ }
+
+ /* Enforce strict type matching for calls to kfuncs that are acquiring
+ * or releasing a reference, or are no-cast aliases. We do _not_
+ * enforce strict matching for plain KF_TRUSTED_ARGS kfuncs by default,
+ * as we want to enable BPF programs to pass types that are bitwise
+ * equivalent without forcing them to explicitly cast with something
+ * like bpf_cast_to_kern_ctx().
+ *
+ * For example, say we had a type like the following:
+ *
+ * struct bpf_cpumask {
+ * cpumask_t cpumask;
+ * refcount_t usage;
+ * };
+ *
+ * Note that as specified in <linux/cpumask.h>, cpumask_t is typedef'ed
+ * to a struct cpumask, so it would be safe to pass a struct
+ * bpf_cpumask * to a kfunc expecting a struct cpumask *.
+ *
+ * The philosophy here is similar to how we allow scalars of different
+ * types to be passed to kfuncs as long as the size is the same. The
+ * only difference here is that we're simply allowing
+ * btf_struct_ids_match() to walk the struct at the 0th offset, and
+ * resolve types.
+ */
+ if (is_kfunc_acquire(meta) ||
+ (is_kfunc_release(meta) && reg->ref_obj_id) ||
+ btf_type_ids_nocast_alias(&env->log, reg_btf, reg_ref_id, meta->btf, ref_id))
+ strict_type_match = true;
+
+ WARN_ON_ONCE(is_kfunc_trusted_args(meta) && reg->off);
+
+ reg_ref_t = btf_type_skip_modifiers(reg_btf, reg_ref_id, &reg_ref_id);
+ reg_ref_tname = btf_name_by_offset(reg_btf, reg_ref_t->name_off);
+ if (!btf_struct_ids_match(&env->log, reg_btf, reg_ref_id, reg->off, meta->btf, ref_id, strict_type_match)) {
+ verbose(env, "kernel function %s args#%d expected pointer to %s %s but R%d has a pointer to %s %s\n",
+ meta->func_name, argno, btf_type_str(ref_t), ref_tname, argno + 1,
+ btf_type_str(reg_ref_t), reg_ref_tname);
+ return -EINVAL;
+ }
+ return 0;
+}
+
+static int ref_set_non_owning(struct bpf_verifier_env *env, struct bpf_reg_state *reg)
+{
+ struct bpf_verifier_state *state = env->cur_state;
+ struct btf_record *rec = reg_btf_record(reg);
+
+ if (!state->active_lock.ptr) {
+ verbose(env, "verifier internal error: ref_set_non_owning w/o active lock\n");
+ return -EFAULT;
+ }
+
+ if (type_flag(reg->type) & NON_OWN_REF) {
+ verbose(env, "verifier internal error: NON_OWN_REF already set\n");
+ return -EFAULT;
+ }
+
+ reg->type |= NON_OWN_REF;
+ if (rec->refcount_off >= 0)
+ reg->type |= MEM_RCU;
+
+ return 0;
+}
+
+static int ref_convert_owning_non_owning(struct bpf_verifier_env *env, u32 ref_obj_id)
+{
+ struct bpf_func_state *state, *unused;
+ struct bpf_reg_state *reg;
+ int i;
+
+ state = cur_func(env);
+
+ if (!ref_obj_id) {
+ verbose(env, "verifier internal error: ref_obj_id is zero for "
+ "owning -> non-owning conversion\n");
+ return -EFAULT;
+ }
+
+ for (i = 0; i < state->acquired_refs; i++) {
+ if (state->refs[i].id != ref_obj_id)
+ continue;
+
+ /* Clear ref_obj_id here so release_reference doesn't clobber
+ * the whole reg
+ */
+ bpf_for_each_reg_in_vstate(env->cur_state, unused, reg, ({
+ if (reg->ref_obj_id == ref_obj_id) {
+ reg->ref_obj_id = 0;
+ ref_set_non_owning(env, reg);
+ }
+ }));
+ return 0;
+ }
+
+ verbose(env, "verifier internal error: ref state missing for ref_obj_id\n");
+ return -EFAULT;
+}
+
+/* Implementation details:
+ *
+ * Each register points to some region of memory, which we define as an
+ * allocation. Each allocation may embed a bpf_spin_lock which protects any
+ * special BPF objects (bpf_list_head, bpf_rb_root, etc.) part of the same
+ * allocation. The lock and the data it protects are colocated in the same
+ * memory region.
+ *
+ * Hence, everytime a register holds a pointer value pointing to such
+ * allocation, the verifier preserves a unique reg->id for it.
+ *
+ * The verifier remembers the lock 'ptr' and the lock 'id' whenever
+ * bpf_spin_lock is called.
+ *
+ * To enable this, lock state in the verifier captures two values:
+ * active_lock.ptr = Register's type specific pointer
+ * active_lock.id = A unique ID for each register pointer value
+ *
+ * Currently, PTR_TO_MAP_VALUE and PTR_TO_BTF_ID | MEM_ALLOC are the two
+ * supported register types.
+ *
+ * The active_lock.ptr in case of map values is the reg->map_ptr, and in case of
+ * allocated objects is the reg->btf pointer.
+ *
+ * The active_lock.id is non-unique for maps supporting direct_value_addr, as we
+ * can establish the provenance of the map value statically for each distinct
+ * lookup into such maps. They always contain a single map value hence unique
+ * IDs for each pseudo load pessimizes the algorithm and rejects valid programs.
+ *
+ * So, in case of global variables, they use array maps with max_entries = 1,
+ * hence their active_lock.ptr becomes map_ptr and id = 0 (since they all point
+ * into the same map value as max_entries is 1, as described above).
+ *
+ * In case of inner map lookups, the inner map pointer has same map_ptr as the
+ * outer map pointer (in verifier context), but each lookup into an inner map
+ * assigns a fresh reg->id to the lookup, so while lookups into distinct inner
+ * maps from the same outer map share the same map_ptr as active_lock.ptr, they
+ * will get different reg->id assigned to each lookup, hence different
+ * active_lock.id.
+ *
+ * In case of allocated objects, active_lock.ptr is the reg->btf, and the
+ * reg->id is a unique ID preserved after the NULL pointer check on the pointer
+ * returned from bpf_obj_new. Each allocation receives a new reg->id.
+ */
+static int check_reg_allocation_locked(struct bpf_verifier_env *env, struct bpf_reg_state *reg)
+{
+ void *ptr;
+ u32 id;
+
+ switch ((int)reg->type) {
+ case PTR_TO_MAP_VALUE:
+ ptr = reg->map_ptr;
+ break;
+ case PTR_TO_BTF_ID | MEM_ALLOC:
+ ptr = reg->btf;
+ break;
+ default:
+ verbose(env, "verifier internal error: unknown reg type for lock check\n");
+ return -EFAULT;
+ }
+ id = reg->id;
+
+ if (!env->cur_state->active_lock.ptr)
+ return -EINVAL;
+ if (env->cur_state->active_lock.ptr != ptr ||
+ env->cur_state->active_lock.id != id) {
+ verbose(env, "held lock and object are not in the same allocation\n");
+ return -EINVAL;
+ }
+ return 0;
+}
+
+static bool is_bpf_list_api_kfunc(u32 btf_id)
+{
+ return btf_id == special_kfunc_list[KF_bpf_list_push_front_impl] ||
+ btf_id == special_kfunc_list[KF_bpf_list_push_back_impl] ||
+ btf_id == special_kfunc_list[KF_bpf_list_pop_front] ||
+ btf_id == special_kfunc_list[KF_bpf_list_pop_back];
+}
+
+static bool is_bpf_rbtree_api_kfunc(u32 btf_id)
+{
+ return btf_id == special_kfunc_list[KF_bpf_rbtree_add_impl] ||
+ btf_id == special_kfunc_list[KF_bpf_rbtree_remove] ||
+ btf_id == special_kfunc_list[KF_bpf_rbtree_first];
+}
+
+static bool is_bpf_graph_api_kfunc(u32 btf_id)
+{
+ return is_bpf_list_api_kfunc(btf_id) || is_bpf_rbtree_api_kfunc(btf_id) ||
+ btf_id == special_kfunc_list[KF_bpf_refcount_acquire_impl];
+}
+
+static bool is_sync_callback_calling_kfunc(u32 btf_id)
+{
+ return btf_id == special_kfunc_list[KF_bpf_rbtree_add_impl];
+}
+
+static bool is_rbtree_lock_required_kfunc(u32 btf_id)
+{
+ return is_bpf_rbtree_api_kfunc(btf_id);
+}
+
+static bool check_kfunc_is_graph_root_api(struct bpf_verifier_env *env,
+ enum btf_field_type head_field_type,
+ u32 kfunc_btf_id)
+{
+ bool ret;
+
+ switch (head_field_type) {
+ case BPF_LIST_HEAD:
+ ret = is_bpf_list_api_kfunc(kfunc_btf_id);
+ break;
+ case BPF_RB_ROOT:
+ ret = is_bpf_rbtree_api_kfunc(kfunc_btf_id);
+ break;
+ default:
+ verbose(env, "verifier internal error: unexpected graph root argument type %s\n",
+ btf_field_type_name(head_field_type));
+ return false;
+ }
+
+ if (!ret)
+ verbose(env, "verifier internal error: %s head arg for unknown kfunc\n",
+ btf_field_type_name(head_field_type));
+ return ret;
+}
+
+static bool check_kfunc_is_graph_node_api(struct bpf_verifier_env *env,
+ enum btf_field_type node_field_type,
+ u32 kfunc_btf_id)
+{
+ bool ret;
+
+ switch (node_field_type) {
+ case BPF_LIST_NODE:
+ ret = (kfunc_btf_id == special_kfunc_list[KF_bpf_list_push_front_impl] ||
+ kfunc_btf_id == special_kfunc_list[KF_bpf_list_push_back_impl]);
+ break;
+ case BPF_RB_NODE:
+ ret = (kfunc_btf_id == special_kfunc_list[KF_bpf_rbtree_remove] ||
+ kfunc_btf_id == special_kfunc_list[KF_bpf_rbtree_add_impl]);
+ break;
+ default:
+ verbose(env, "verifier internal error: unexpected graph node argument type %s\n",
+ btf_field_type_name(node_field_type));
+ return false;
+ }
+
+ if (!ret)
+ verbose(env, "verifier internal error: %s node arg for unknown kfunc\n",
+ btf_field_type_name(node_field_type));
+ return ret;
+}
+
+static int
+__process_kf_arg_ptr_to_graph_root(struct bpf_verifier_env *env,
+ struct bpf_reg_state *reg, u32 regno,
+ struct bpf_kfunc_call_arg_meta *meta,
+ enum btf_field_type head_field_type,
+ struct btf_field **head_field)
+{
+ const char *head_type_name;
+ struct btf_field *field;
+ struct btf_record *rec;
+ u32 head_off;
+
+ if (meta->btf != btf_vmlinux) {
+ verbose(env, "verifier internal error: unexpected btf mismatch in kfunc call\n");
+ return -EFAULT;
+ }
+
+ if (!check_kfunc_is_graph_root_api(env, head_field_type, meta->func_id))
+ return -EFAULT;
+
+ head_type_name = btf_field_type_name(head_field_type);
+ if (!tnum_is_const(reg->var_off)) {
+ verbose(env,
+ "R%d doesn't have constant offset. %s has to be at the constant offset\n",
+ regno, head_type_name);
+ return -EINVAL;
+ }
+
+ rec = reg_btf_record(reg);
+ head_off = reg->off + reg->var_off.value;
+ field = btf_record_find(rec, head_off, head_field_type);
+ if (!field) {
+ verbose(env, "%s not found at offset=%u\n", head_type_name, head_off);
+ return -EINVAL;
+ }
+
+ /* All functions require bpf_list_head to be protected using a bpf_spin_lock */
+ if (check_reg_allocation_locked(env, reg)) {
+ verbose(env, "bpf_spin_lock at off=%d must be held for %s\n",
+ rec->spin_lock_off, head_type_name);
+ return -EINVAL;
+ }
+
+ if (*head_field) {
+ verbose(env, "verifier internal error: repeating %s arg\n", head_type_name);
+ return -EFAULT;
+ }
+ *head_field = field;
+ return 0;
+}
+
+static int process_kf_arg_ptr_to_list_head(struct bpf_verifier_env *env,
+ struct bpf_reg_state *reg, u32 regno,
+ struct bpf_kfunc_call_arg_meta *meta)
+{
+ return __process_kf_arg_ptr_to_graph_root(env, reg, regno, meta, BPF_LIST_HEAD,
+ &meta->arg_list_head.field);
+}
+
+static int process_kf_arg_ptr_to_rbtree_root(struct bpf_verifier_env *env,
+ struct bpf_reg_state *reg, u32 regno,
+ struct bpf_kfunc_call_arg_meta *meta)
+{
+ return __process_kf_arg_ptr_to_graph_root(env, reg, regno, meta, BPF_RB_ROOT,
+ &meta->arg_rbtree_root.field);
+}
+
+static int
+__process_kf_arg_ptr_to_graph_node(struct bpf_verifier_env *env,
+ struct bpf_reg_state *reg, u32 regno,
+ struct bpf_kfunc_call_arg_meta *meta,
+ enum btf_field_type head_field_type,
+ enum btf_field_type node_field_type,
+ struct btf_field **node_field)
+{
+ const char *node_type_name;
+ const struct btf_type *et, *t;
+ struct btf_field *field;
+ u32 node_off;
+
+ if (meta->btf != btf_vmlinux) {
+ verbose(env, "verifier internal error: unexpected btf mismatch in kfunc call\n");
+ return -EFAULT;
+ }
+
+ if (!check_kfunc_is_graph_node_api(env, node_field_type, meta->func_id))
+ return -EFAULT;
+
+ node_type_name = btf_field_type_name(node_field_type);
+ if (!tnum_is_const(reg->var_off)) {
+ verbose(env,
+ "R%d doesn't have constant offset. %s has to be at the constant offset\n",
+ regno, node_type_name);
+ return -EINVAL;
+ }
+
+ node_off = reg->off + reg->var_off.value;
+ field = reg_find_field_offset(reg, node_off, node_field_type);
+ if (!field || field->offset != node_off) {
+ verbose(env, "%s not found at offset=%u\n", node_type_name, node_off);
+ return -EINVAL;
+ }
+
+ field = *node_field;
+
+ et = btf_type_by_id(field->graph_root.btf, field->graph_root.value_btf_id);
+ t = btf_type_by_id(reg->btf, reg->btf_id);
+ if (!btf_struct_ids_match(&env->log, reg->btf, reg->btf_id, 0, field->graph_root.btf,
+ field->graph_root.value_btf_id, true)) {
+ verbose(env, "operation on %s expects arg#1 %s at offset=%d "
+ "in struct %s, but arg is at offset=%d in struct %s\n",
+ btf_field_type_name(head_field_type),
+ btf_field_type_name(node_field_type),
+ field->graph_root.node_offset,
+ btf_name_by_offset(field->graph_root.btf, et->name_off),
+ node_off, btf_name_by_offset(reg->btf, t->name_off));
+ return -EINVAL;
+ }
+ meta->arg_btf = reg->btf;
+ meta->arg_btf_id = reg->btf_id;
+
+ if (node_off != field->graph_root.node_offset) {
+ verbose(env, "arg#1 offset=%d, but expected %s at offset=%d in struct %s\n",
+ node_off, btf_field_type_name(node_field_type),
+ field->graph_root.node_offset,
+ btf_name_by_offset(field->graph_root.btf, et->name_off));
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
+static int process_kf_arg_ptr_to_list_node(struct bpf_verifier_env *env,
+ struct bpf_reg_state *reg, u32 regno,
+ struct bpf_kfunc_call_arg_meta *meta)
+{
+ return __process_kf_arg_ptr_to_graph_node(env, reg, regno, meta,
+ BPF_LIST_HEAD, BPF_LIST_NODE,
+ &meta->arg_list_head.field);
+}
+
+static int process_kf_arg_ptr_to_rbtree_node(struct bpf_verifier_env *env,
+ struct bpf_reg_state *reg, u32 regno,
+ struct bpf_kfunc_call_arg_meta *meta)
+{
+ return __process_kf_arg_ptr_to_graph_node(env, reg, regno, meta,
+ BPF_RB_ROOT, BPF_RB_NODE,
+ &meta->arg_rbtree_root.field);
+}
+
+static int check_kfunc_args(struct bpf_verifier_env *env, struct bpf_kfunc_call_arg_meta *meta,
+ int insn_idx)
+{
+ const char *func_name = meta->func_name, *ref_tname;
+ const struct btf *btf = meta->btf;
+ const struct btf_param *args;
+ struct btf_record *rec;
+ u32 i, nargs;
+ int ret;
+
+ args = (const struct btf_param *)(meta->func_proto + 1);
+ nargs = btf_type_vlen(meta->func_proto);
+ if (nargs > MAX_BPF_FUNC_REG_ARGS) {
+ verbose(env, "Function %s has %d > %d args\n", func_name, nargs,
+ MAX_BPF_FUNC_REG_ARGS);
+ return -EINVAL;
+ }
+
+ /* Check that BTF function arguments match actual types that the
+ * verifier sees.
+ */
+ for (i = 0; i < nargs; i++) {
+ struct bpf_reg_state *regs = cur_regs(env), *reg = &regs[i + 1];
+ const struct btf_type *t, *ref_t, *resolve_ret;
+ enum bpf_arg_type arg_type = ARG_DONTCARE;
+ u32 regno = i + 1, ref_id, type_size;
+ bool is_ret_buf_sz = false;
+ int kf_arg_type;
+
+ t = btf_type_skip_modifiers(btf, args[i].type, NULL);
+
+ if (is_kfunc_arg_ignore(btf, &args[i]))
+ continue;
+
+ if (btf_type_is_scalar(t)) {
+ if (reg->type != SCALAR_VALUE) {
+ verbose(env, "R%d is not a scalar\n", regno);
+ return -EINVAL;
+ }
+
+ if (is_kfunc_arg_constant(meta->btf, &args[i])) {
+ if (meta->arg_constant.found) {
+ verbose(env, "verifier internal error: only one constant argument permitted\n");
+ return -EFAULT;
+ }
+ if (!tnum_is_const(reg->var_off)) {
+ verbose(env, "R%d must be a known constant\n", regno);
+ return -EINVAL;
+ }
+ ret = mark_chain_precision(env, regno);
+ if (ret < 0)
+ return ret;
+ meta->arg_constant.found = true;
+ meta->arg_constant.value = reg->var_off.value;
+ } else if (is_kfunc_arg_scalar_with_name(btf, &args[i], "rdonly_buf_size")) {
+ meta->r0_rdonly = true;
+ is_ret_buf_sz = true;
+ } else if (is_kfunc_arg_scalar_with_name(btf, &args[i], "rdwr_buf_size")) {
+ is_ret_buf_sz = true;
+ }
+
+ if (is_ret_buf_sz) {
+ if (meta->r0_size) {
+ verbose(env, "2 or more rdonly/rdwr_buf_size parameters for kfunc");
+ return -EINVAL;
+ }
+
+ if (!tnum_is_const(reg->var_off)) {
+ verbose(env, "R%d is not a const\n", regno);
+ return -EINVAL;
+ }
+
+ meta->r0_size = reg->var_off.value;
+ ret = mark_chain_precision(env, regno);
+ if (ret)
+ return ret;
+ }
+ continue;
+ }
+
+ if (!btf_type_is_ptr(t)) {
+ verbose(env, "Unrecognized arg#%d type %s\n", i, btf_type_str(t));
+ return -EINVAL;
+ }
+
+ if ((is_kfunc_trusted_args(meta) || is_kfunc_rcu(meta)) &&
+ (register_is_null(reg) || type_may_be_null(reg->type))) {
+ verbose(env, "Possibly NULL pointer passed to trusted arg%d\n", i);
+ return -EACCES;
+ }
+
+ if (reg->ref_obj_id) {
+ if (is_kfunc_release(meta) && meta->ref_obj_id) {
+ verbose(env, "verifier internal error: more than one arg with ref_obj_id R%d %u %u\n",
+ regno, reg->ref_obj_id,
+ meta->ref_obj_id);
+ return -EFAULT;
+ }
+ meta->ref_obj_id = reg->ref_obj_id;
+ if (is_kfunc_release(meta))
+ meta->release_regno = regno;
+ }
+
+ ref_t = btf_type_skip_modifiers(btf, t->type, &ref_id);
+ ref_tname = btf_name_by_offset(btf, ref_t->name_off);
+
+ kf_arg_type = get_kfunc_ptr_arg_type(env, meta, t, ref_t, ref_tname, args, i, nargs);
+ if (kf_arg_type < 0)
+ return kf_arg_type;
+
+ switch (kf_arg_type) {
+ case KF_ARG_PTR_TO_ALLOC_BTF_ID:
+ case KF_ARG_PTR_TO_BTF_ID:
+ if (!is_kfunc_trusted_args(meta) && !is_kfunc_rcu(meta))
+ break;
+
+ if (!is_trusted_reg(reg)) {
+ if (!is_kfunc_rcu(meta)) {
+ verbose(env, "R%d must be referenced or trusted\n", regno);
+ return -EINVAL;
+ }
+ if (!is_rcu_reg(reg)) {
+ verbose(env, "R%d must be a rcu pointer\n", regno);
+ return -EINVAL;
+ }
+ }
+
+ fallthrough;
+ case KF_ARG_PTR_TO_CTX:
+ /* Trusted arguments have the same offset checks as release arguments */
+ arg_type |= OBJ_RELEASE;
+ break;
+ case KF_ARG_PTR_TO_DYNPTR:
+ case KF_ARG_PTR_TO_ITER:
+ case KF_ARG_PTR_TO_LIST_HEAD:
+ case KF_ARG_PTR_TO_LIST_NODE:
+ case KF_ARG_PTR_TO_RB_ROOT:
+ case KF_ARG_PTR_TO_RB_NODE:
+ case KF_ARG_PTR_TO_MEM:
+ case KF_ARG_PTR_TO_MEM_SIZE:
+ case KF_ARG_PTR_TO_CALLBACK:
+ case KF_ARG_PTR_TO_REFCOUNTED_KPTR:
+ /* Trusted by default */
+ break;
+ default:
+ WARN_ON_ONCE(1);
+ return -EFAULT;
+ }
+
+ if (is_kfunc_release(meta) && reg->ref_obj_id)
+ arg_type |= OBJ_RELEASE;
+ ret = check_func_arg_reg_off(env, reg, regno, arg_type);
+ if (ret < 0)
+ return ret;
+
+ switch (kf_arg_type) {
+ case KF_ARG_PTR_TO_CTX:
+ if (reg->type != PTR_TO_CTX) {
+ verbose(env, "arg#%d expected pointer to ctx, but got %s\n", i, btf_type_str(t));
+ return -EINVAL;
+ }
+
+ if (meta->func_id == special_kfunc_list[KF_bpf_cast_to_kern_ctx]) {
+ ret = get_kern_ctx_btf_id(&env->log, resolve_prog_type(env->prog));
+ if (ret < 0)
+ return -EINVAL;
+ meta->ret_btf_id = ret;
+ }
+ break;
+ case KF_ARG_PTR_TO_ALLOC_BTF_ID:
+ if (reg->type != (PTR_TO_BTF_ID | MEM_ALLOC)) {
+ verbose(env, "arg#%d expected pointer to allocated object\n", i);
+ return -EINVAL;
+ }
+ if (!reg->ref_obj_id) {
+ verbose(env, "allocated object must be referenced\n");
+ return -EINVAL;
+ }
+ if (meta->btf == btf_vmlinux &&
+ meta->func_id == special_kfunc_list[KF_bpf_obj_drop_impl]) {
+ meta->arg_btf = reg->btf;
+ meta->arg_btf_id = reg->btf_id;
+ }
+ break;
+ case KF_ARG_PTR_TO_DYNPTR:
+ {
+ enum bpf_arg_type dynptr_arg_type = ARG_PTR_TO_DYNPTR;
+ int clone_ref_obj_id = 0;
+
+ if (reg->type != PTR_TO_STACK &&
+ reg->type != CONST_PTR_TO_DYNPTR) {
+ verbose(env, "arg#%d expected pointer to stack or dynptr_ptr\n", i);
+ return -EINVAL;
+ }
+
+ if (reg->type == CONST_PTR_TO_DYNPTR)
+ dynptr_arg_type |= MEM_RDONLY;
+
+ if (is_kfunc_arg_uninit(btf, &args[i]))
+ dynptr_arg_type |= MEM_UNINIT;
+
+ if (meta->func_id == special_kfunc_list[KF_bpf_dynptr_from_skb]) {
+ dynptr_arg_type |= DYNPTR_TYPE_SKB;
+ } else if (meta->func_id == special_kfunc_list[KF_bpf_dynptr_from_xdp]) {
+ dynptr_arg_type |= DYNPTR_TYPE_XDP;
+ } else if (meta->func_id == special_kfunc_list[KF_bpf_dynptr_clone] &&
+ (dynptr_arg_type & MEM_UNINIT)) {
+ enum bpf_dynptr_type parent_type = meta->initialized_dynptr.type;
+
+ if (parent_type == BPF_DYNPTR_TYPE_INVALID) {
+ verbose(env, "verifier internal error: no dynptr type for parent of clone\n");
+ return -EFAULT;
+ }
+
+ dynptr_arg_type |= (unsigned int)get_dynptr_type_flag(parent_type);
+ clone_ref_obj_id = meta->initialized_dynptr.ref_obj_id;
+ if (dynptr_type_refcounted(parent_type) && !clone_ref_obj_id) {
+ verbose(env, "verifier internal error: missing ref obj id for parent of clone\n");
+ return -EFAULT;
+ }
+ }
+
+ ret = process_dynptr_func(env, regno, insn_idx, dynptr_arg_type, clone_ref_obj_id);
+ if (ret < 0)
+ return ret;
+
+ if (!(dynptr_arg_type & MEM_UNINIT)) {
+ int id = dynptr_id(env, reg);
+
+ if (id < 0) {
+ verbose(env, "verifier internal error: failed to obtain dynptr id\n");
+ return id;
+ }
+ meta->initialized_dynptr.id = id;
+ meta->initialized_dynptr.type = dynptr_get_type(env, reg);
+ meta->initialized_dynptr.ref_obj_id = dynptr_ref_obj_id(env, reg);
+ }
+
+ break;
+ }
+ case KF_ARG_PTR_TO_ITER:
+ ret = process_iter_arg(env, regno, insn_idx, meta);
+ if (ret < 0)
+ return ret;
+ break;
+ case KF_ARG_PTR_TO_LIST_HEAD:
+ if (reg->type != PTR_TO_MAP_VALUE &&
+ reg->type != (PTR_TO_BTF_ID | MEM_ALLOC)) {
+ verbose(env, "arg#%d expected pointer to map value or allocated object\n", i);
+ return -EINVAL;
+ }
+ if (reg->type == (PTR_TO_BTF_ID | MEM_ALLOC) && !reg->ref_obj_id) {
+ verbose(env, "allocated object must be referenced\n");
+ return -EINVAL;
+ }
+ ret = process_kf_arg_ptr_to_list_head(env, reg, regno, meta);
+ if (ret < 0)
+ return ret;
+ break;
+ case KF_ARG_PTR_TO_RB_ROOT:
+ if (reg->type != PTR_TO_MAP_VALUE &&
+ reg->type != (PTR_TO_BTF_ID | MEM_ALLOC)) {
+ verbose(env, "arg#%d expected pointer to map value or allocated object\n", i);
+ return -EINVAL;
+ }
+ if (reg->type == (PTR_TO_BTF_ID | MEM_ALLOC) && !reg->ref_obj_id) {
+ verbose(env, "allocated object must be referenced\n");
+ return -EINVAL;
+ }
+ ret = process_kf_arg_ptr_to_rbtree_root(env, reg, regno, meta);
+ if (ret < 0)
+ return ret;
+ break;
+ case KF_ARG_PTR_TO_LIST_NODE:
+ if (reg->type != (PTR_TO_BTF_ID | MEM_ALLOC)) {
+ verbose(env, "arg#%d expected pointer to allocated object\n", i);
+ return -EINVAL;
+ }
+ if (!reg->ref_obj_id) {
+ verbose(env, "allocated object must be referenced\n");
+ return -EINVAL;
+ }
+ ret = process_kf_arg_ptr_to_list_node(env, reg, regno, meta);
+ if (ret < 0)
+ return ret;
+ break;
+ case KF_ARG_PTR_TO_RB_NODE:
+ if (meta->func_id == special_kfunc_list[KF_bpf_rbtree_remove]) {
+ if (!type_is_non_owning_ref(reg->type) || reg->ref_obj_id) {
+ verbose(env, "rbtree_remove node input must be non-owning ref\n");
+ return -EINVAL;
+ }
+ if (in_rbtree_lock_required_cb(env)) {
+ verbose(env, "rbtree_remove not allowed in rbtree cb\n");
+ return -EINVAL;
+ }
+ } else {
+ if (reg->type != (PTR_TO_BTF_ID | MEM_ALLOC)) {
+ verbose(env, "arg#%d expected pointer to allocated object\n", i);
+ return -EINVAL;
+ }
+ if (!reg->ref_obj_id) {
+ verbose(env, "allocated object must be referenced\n");
+ return -EINVAL;
+ }
+ }
+
+ ret = process_kf_arg_ptr_to_rbtree_node(env, reg, regno, meta);
+ if (ret < 0)
+ return ret;
+ break;
+ case KF_ARG_PTR_TO_BTF_ID:
+ /* Only base_type is checked, further checks are done here */
+ if ((base_type(reg->type) != PTR_TO_BTF_ID ||
+ (bpf_type_has_unsafe_modifiers(reg->type) && !is_rcu_reg(reg))) &&
+ !reg2btf_ids[base_type(reg->type)]) {
+ verbose(env, "arg#%d is %s ", i, reg_type_str(env, reg->type));
+ verbose(env, "expected %s or socket\n",
+ reg_type_str(env, base_type(reg->type) |
+ (type_flag(reg->type) & BPF_REG_TRUSTED_MODIFIERS)));
+ return -EINVAL;
+ }
+ ret = process_kf_arg_ptr_to_btf_id(env, reg, ref_t, ref_tname, ref_id, meta, i);
+ if (ret < 0)
+ return ret;
+ break;
+ case KF_ARG_PTR_TO_MEM:
+ resolve_ret = btf_resolve_size(btf, ref_t, &type_size);
+ if (IS_ERR(resolve_ret)) {
+ verbose(env, "arg#%d reference type('%s %s') size cannot be determined: %ld\n",
+ i, btf_type_str(ref_t), ref_tname, PTR_ERR(resolve_ret));
+ return -EINVAL;
+ }
+ ret = check_mem_reg(env, reg, regno, type_size);
+ if (ret < 0)
+ return ret;
+ break;
+ case KF_ARG_PTR_TO_MEM_SIZE:
+ {
+ struct bpf_reg_state *buff_reg = &regs[regno];
+ const struct btf_param *buff_arg = &args[i];
+ struct bpf_reg_state *size_reg = &regs[regno + 1];
+ const struct btf_param *size_arg = &args[i + 1];
+
+ if (!register_is_null(buff_reg) || !is_kfunc_arg_optional(meta->btf, buff_arg)) {
+ ret = check_kfunc_mem_size_reg(env, size_reg, regno + 1);
+ if (ret < 0) {
+ verbose(env, "arg#%d arg#%d memory, len pair leads to invalid memory access\n", i, i + 1);
+ return ret;
+ }
+ }
+
+ if (is_kfunc_arg_const_mem_size(meta->btf, size_arg, size_reg)) {
+ if (meta->arg_constant.found) {
+ verbose(env, "verifier internal error: only one constant argument permitted\n");
+ return -EFAULT;
+ }
+ if (!tnum_is_const(size_reg->var_off)) {
+ verbose(env, "R%d must be a known constant\n", regno + 1);
+ return -EINVAL;
+ }
+ meta->arg_constant.found = true;
+ meta->arg_constant.value = size_reg->var_off.value;
+ }
+
+ /* Skip next '__sz' or '__szk' argument */
+ i++;
+ break;
+ }
+ case KF_ARG_PTR_TO_CALLBACK:
+ if (reg->type != PTR_TO_FUNC) {
+ verbose(env, "arg%d expected pointer to func\n", i);
+ return -EINVAL;
+ }
+ meta->subprogno = reg->subprogno;
+ break;
+ case KF_ARG_PTR_TO_REFCOUNTED_KPTR:
+ if (!type_is_ptr_alloc_obj(reg->type)) {
+ verbose(env, "arg#%d is neither owning or non-owning ref\n", i);
+ return -EINVAL;
+ }
+ if (!type_is_non_owning_ref(reg->type))
+ meta->arg_owning_ref = true;
+
+ rec = reg_btf_record(reg);
+ if (!rec) {
+ verbose(env, "verifier internal error: Couldn't find btf_record\n");
+ return -EFAULT;
+ }
+
+ if (rec->refcount_off < 0) {
+ verbose(env, "arg#%d doesn't point to a type with bpf_refcount field\n", i);
+ return -EINVAL;
+ }
+
+ meta->arg_btf = reg->btf;
+ meta->arg_btf_id = reg->btf_id;
+ break;
+ }
+ }
+
+ if (is_kfunc_release(meta) && !meta->release_regno) {
+ verbose(env, "release kernel function %s expects refcounted PTR_TO_BTF_ID\n",
+ func_name);
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
+static int fetch_kfunc_meta(struct bpf_verifier_env *env,
+ struct bpf_insn *insn,
+ struct bpf_kfunc_call_arg_meta *meta,
+ const char **kfunc_name)
+{
+ const struct btf_type *func, *func_proto;
+ u32 func_id, *kfunc_flags;
+ const char *func_name;
+ struct btf *desc_btf;
+
+ if (kfunc_name)
+ *kfunc_name = NULL;
+
+ if (!insn->imm)
+ return -EINVAL;
+
+ desc_btf = find_kfunc_desc_btf(env, insn->off);
+ if (IS_ERR(desc_btf))
+ return PTR_ERR(desc_btf);
+
+ func_id = insn->imm;
+ func = btf_type_by_id(desc_btf, func_id);
+ func_name = btf_name_by_offset(desc_btf, func->name_off);
+ if (kfunc_name)
+ *kfunc_name = func_name;
+ func_proto = btf_type_by_id(desc_btf, func->type);
+
+ kfunc_flags = btf_kfunc_id_set_contains(desc_btf, func_id, env->prog);
+ if (!kfunc_flags) {
+ return -EACCES;
+ }
+
+ memset(meta, 0, sizeof(*meta));
+ meta->btf = desc_btf;
+ meta->func_id = func_id;
+ meta->kfunc_flags = *kfunc_flags;
+ meta->func_proto = func_proto;
+ meta->func_name = func_name;
+
+ return 0;
+}
+
+static int check_kfunc_call(struct bpf_verifier_env *env, struct bpf_insn *insn,
+ int *insn_idx_p)
+{
+ const struct btf_type *t, *ptr_type;
+ u32 i, nargs, ptr_type_id, release_ref_obj_id;
+ struct bpf_reg_state *regs = cur_regs(env);
+ const char *func_name, *ptr_type_name;
+ bool sleepable, rcu_lock, rcu_unlock;
+ struct bpf_kfunc_call_arg_meta meta;
+ struct bpf_insn_aux_data *insn_aux;
+ int err, insn_idx = *insn_idx_p;
+ const struct btf_param *args;
+ const struct btf_type *ret_t;
+ struct btf *desc_btf;
+
+ /* skip for now, but return error when we find this in fixup_kfunc_call */
+ if (!insn->imm)
+ return 0;
+
+ err = fetch_kfunc_meta(env, insn, &meta, &func_name);
+ if (err == -EACCES && func_name)
+ verbose(env, "calling kernel function %s is not allowed\n", func_name);
+ if (err)
+ return err;
+ desc_btf = meta.btf;
+ insn_aux = &env->insn_aux_data[insn_idx];
+
+ insn_aux->is_iter_next = is_iter_next_kfunc(&meta);
+
+ if (is_kfunc_destructive(&meta) && !capable(CAP_SYS_BOOT)) {
+ verbose(env, "destructive kfunc calls require CAP_SYS_BOOT capability\n");
+ return -EACCES;
+ }
+
+ sleepable = is_kfunc_sleepable(&meta);
+ if (sleepable && !env->prog->aux->sleepable) {
+ verbose(env, "program must be sleepable to call sleepable kfunc %s\n", func_name);
+ return -EACCES;
+ }
+
+ /* Check the arguments */
+ err = check_kfunc_args(env, &meta, insn_idx);
+ if (err < 0)
+ return err;
+
+ if (meta.func_id == special_kfunc_list[KF_bpf_rbtree_add_impl]) {
+ err = push_callback_call(env, insn, insn_idx, meta.subprogno,
+ set_rbtree_add_callback_state);
+ if (err) {
+ verbose(env, "kfunc %s#%d failed callback verification\n",
+ func_name, meta.func_id);
+ return err;
+ }
+ }
+
+ rcu_lock = is_kfunc_bpf_rcu_read_lock(&meta);
+ rcu_unlock = is_kfunc_bpf_rcu_read_unlock(&meta);
+
+ if (env->cur_state->active_rcu_lock) {
+ struct bpf_func_state *state;
+ struct bpf_reg_state *reg;
+
+ if (in_rbtree_lock_required_cb(env) && (rcu_lock || rcu_unlock)) {
+ verbose(env, "Calling bpf_rcu_read_{lock,unlock} in unnecessary rbtree callback\n");
+ return -EACCES;
+ }
+
+ if (rcu_lock) {
+ verbose(env, "nested rcu read lock (kernel function %s)\n", func_name);
+ return -EINVAL;
+ } else if (rcu_unlock) {
+ bpf_for_each_reg_in_vstate(env->cur_state, state, reg, ({
+ if (reg->type & MEM_RCU) {
+ reg->type &= ~(MEM_RCU | PTR_MAYBE_NULL);
+ reg->type |= PTR_UNTRUSTED;
+ }
+ }));
+ env->cur_state->active_rcu_lock = false;
+ } else if (sleepable) {
+ verbose(env, "kernel func %s is sleepable within rcu_read_lock region\n", func_name);
+ return -EACCES;
+ }
+ } else if (rcu_lock) {
+ env->cur_state->active_rcu_lock = true;
+ } else if (rcu_unlock) {
+ verbose(env, "unmatched rcu read unlock (kernel function %s)\n", func_name);
+ return -EINVAL;
+ }
+
+ /* In case of release function, we get register number of refcounted
+ * PTR_TO_BTF_ID in bpf_kfunc_arg_meta, do the release now.
+ */
+ if (meta.release_regno) {
+ err = release_reference(env, regs[meta.release_regno].ref_obj_id);
+ if (err) {
+ verbose(env, "kfunc %s#%d reference has not been acquired before\n",
+ func_name, meta.func_id);
+ return err;
+ }
+ }
+
+ if (meta.func_id == special_kfunc_list[KF_bpf_list_push_front_impl] ||
+ meta.func_id == special_kfunc_list[KF_bpf_list_push_back_impl] ||
+ meta.func_id == special_kfunc_list[KF_bpf_rbtree_add_impl]) {
+ release_ref_obj_id = regs[BPF_REG_2].ref_obj_id;
+ insn_aux->insert_off = regs[BPF_REG_2].off;
+ insn_aux->kptr_struct_meta = btf_find_struct_meta(meta.arg_btf, meta.arg_btf_id);
+ err = ref_convert_owning_non_owning(env, release_ref_obj_id);
+ if (err) {
+ verbose(env, "kfunc %s#%d conversion of owning ref to non-owning failed\n",
+ func_name, meta.func_id);
+ return err;
+ }
+
+ err = release_reference(env, release_ref_obj_id);
+ if (err) {
+ verbose(env, "kfunc %s#%d reference has not been acquired before\n",
+ func_name, meta.func_id);
+ return err;
+ }
+ }
+
+ for (i = 0; i < CALLER_SAVED_REGS; i++)
+ mark_reg_not_init(env, regs, caller_saved[i]);
+
+ /* Check return type */
+ t = btf_type_skip_modifiers(desc_btf, meta.func_proto->type, NULL);
+
+ if (is_kfunc_acquire(&meta) && !btf_type_is_struct_ptr(meta.btf, t)) {
+ /* Only exception is bpf_obj_new_impl */
+ if (meta.btf != btf_vmlinux ||
+ (meta.func_id != special_kfunc_list[KF_bpf_obj_new_impl] &&
+ meta.func_id != special_kfunc_list[KF_bpf_refcount_acquire_impl])) {
+ verbose(env, "acquire kernel function does not return PTR_TO_BTF_ID\n");
+ return -EINVAL;
+ }
+ }
+
+ if (btf_type_is_scalar(t)) {
+ mark_reg_unknown(env, regs, BPF_REG_0);
+ mark_btf_func_reg_size(env, BPF_REG_0, t->size);
+ } else if (btf_type_is_ptr(t)) {
+ ptr_type = btf_type_skip_modifiers(desc_btf, t->type, &ptr_type_id);
+
+ if (meta.btf == btf_vmlinux && btf_id_set_contains(&special_kfunc_set, meta.func_id)) {
+ if (meta.func_id == special_kfunc_list[KF_bpf_obj_new_impl]) {
+ struct btf *ret_btf;
+ u32 ret_btf_id;
+
+ if (unlikely(!bpf_global_ma_set))
+ return -ENOMEM;
+
+ if (((u64)(u32)meta.arg_constant.value) != meta.arg_constant.value) {
+ verbose(env, "local type ID argument must be in range [0, U32_MAX]\n");
+ return -EINVAL;
+ }
+
+ ret_btf = env->prog->aux->btf;
+ ret_btf_id = meta.arg_constant.value;
+
+ /* This may be NULL due to user not supplying a BTF */
+ if (!ret_btf) {
+ verbose(env, "bpf_obj_new requires prog BTF\n");
+ return -EINVAL;
+ }
+
+ ret_t = btf_type_by_id(ret_btf, ret_btf_id);
+ if (!ret_t || !__btf_type_is_struct(ret_t)) {
+ verbose(env, "bpf_obj_new type ID argument must be of a struct\n");
+ return -EINVAL;
+ }
+
+ mark_reg_known_zero(env, regs, BPF_REG_0);
+ regs[BPF_REG_0].type = PTR_TO_BTF_ID | MEM_ALLOC;
+ regs[BPF_REG_0].btf = ret_btf;
+ regs[BPF_REG_0].btf_id = ret_btf_id;
+
+ insn_aux->obj_new_size = ret_t->size;
+ insn_aux->kptr_struct_meta =
+ btf_find_struct_meta(ret_btf, ret_btf_id);
+ } else if (meta.func_id == special_kfunc_list[KF_bpf_refcount_acquire_impl]) {
+ mark_reg_known_zero(env, regs, BPF_REG_0);
+ regs[BPF_REG_0].type = PTR_TO_BTF_ID | MEM_ALLOC;
+ regs[BPF_REG_0].btf = meta.arg_btf;
+ regs[BPF_REG_0].btf_id = meta.arg_btf_id;
+
+ insn_aux->kptr_struct_meta =
+ btf_find_struct_meta(meta.arg_btf,
+ meta.arg_btf_id);
+ } else if (meta.func_id == special_kfunc_list[KF_bpf_list_pop_front] ||
+ meta.func_id == special_kfunc_list[KF_bpf_list_pop_back]) {
+ struct btf_field *field = meta.arg_list_head.field;
+
+ mark_reg_graph_node(regs, BPF_REG_0, &field->graph_root);
+ } else if (meta.func_id == special_kfunc_list[KF_bpf_rbtree_remove] ||
+ meta.func_id == special_kfunc_list[KF_bpf_rbtree_first]) {
+ struct btf_field *field = meta.arg_rbtree_root.field;
+
+ mark_reg_graph_node(regs, BPF_REG_0, &field->graph_root);
+ } else if (meta.func_id == special_kfunc_list[KF_bpf_cast_to_kern_ctx]) {
+ mark_reg_known_zero(env, regs, BPF_REG_0);
+ regs[BPF_REG_0].type = PTR_TO_BTF_ID | PTR_TRUSTED;
+ regs[BPF_REG_0].btf = desc_btf;
+ regs[BPF_REG_0].btf_id = meta.ret_btf_id;
+ } else if (meta.func_id == special_kfunc_list[KF_bpf_rdonly_cast]) {
+ ret_t = btf_type_by_id(desc_btf, meta.arg_constant.value);
+ if (!ret_t || !btf_type_is_struct(ret_t)) {
+ verbose(env,
+ "kfunc bpf_rdonly_cast type ID argument must be of a struct\n");
+ return -EINVAL;
+ }
+
+ mark_reg_known_zero(env, regs, BPF_REG_0);
+ regs[BPF_REG_0].type = PTR_TO_BTF_ID | PTR_UNTRUSTED;
+ regs[BPF_REG_0].btf = desc_btf;
+ regs[BPF_REG_0].btf_id = meta.arg_constant.value;
+ } else if (meta.func_id == special_kfunc_list[KF_bpf_dynptr_slice] ||
+ meta.func_id == special_kfunc_list[KF_bpf_dynptr_slice_rdwr]) {
+ enum bpf_type_flag type_flag = get_dynptr_type_flag(meta.initialized_dynptr.type);
+
+ mark_reg_known_zero(env, regs, BPF_REG_0);
+
+ if (!meta.arg_constant.found) {
+ verbose(env, "verifier internal error: bpf_dynptr_slice(_rdwr) no constant size\n");
+ return -EFAULT;
+ }
+
+ regs[BPF_REG_0].mem_size = meta.arg_constant.value;
+
+ /* PTR_MAYBE_NULL will be added when is_kfunc_ret_null is checked */
+ regs[BPF_REG_0].type = PTR_TO_MEM | type_flag;
+
+ if (meta.func_id == special_kfunc_list[KF_bpf_dynptr_slice]) {
+ regs[BPF_REG_0].type |= MEM_RDONLY;
+ } else {
+ /* this will set env->seen_direct_write to true */
+ if (!may_access_direct_pkt_data(env, NULL, BPF_WRITE)) {
+ verbose(env, "the prog does not allow writes to packet data\n");
+ return -EINVAL;
+ }
+ }
+
+ if (!meta.initialized_dynptr.id) {
+ verbose(env, "verifier internal error: no dynptr id\n");
+ return -EFAULT;
+ }
+ regs[BPF_REG_0].dynptr_id = meta.initialized_dynptr.id;
+
+ /* we don't need to set BPF_REG_0's ref obj id
+ * because packet slices are not refcounted (see
+ * dynptr_type_refcounted)
+ */
+ } else {
+ verbose(env, "kernel function %s unhandled dynamic return type\n",
+ meta.func_name);
+ return -EFAULT;
+ }
+ } else if (!__btf_type_is_struct(ptr_type)) {
+ if (!meta.r0_size) {
+ __u32 sz;
+
+ if (!IS_ERR(btf_resolve_size(desc_btf, ptr_type, &sz))) {
+ meta.r0_size = sz;
+ meta.r0_rdonly = true;
+ }
+ }
+ if (!meta.r0_size) {
+ ptr_type_name = btf_name_by_offset(desc_btf,
+ ptr_type->name_off);
+ verbose(env,
+ "kernel function %s returns pointer type %s %s is not supported\n",
+ func_name,
+ btf_type_str(ptr_type),
+ ptr_type_name);
+ return -EINVAL;
+ }
+
+ mark_reg_known_zero(env, regs, BPF_REG_0);
+ regs[BPF_REG_0].type = PTR_TO_MEM;
+ regs[BPF_REG_0].mem_size = meta.r0_size;
+
+ if (meta.r0_rdonly)
+ regs[BPF_REG_0].type |= MEM_RDONLY;
+
+ /* Ensures we don't access the memory after a release_reference() */
+ if (meta.ref_obj_id)
+ regs[BPF_REG_0].ref_obj_id = meta.ref_obj_id;
+ } else {
+ mark_reg_known_zero(env, regs, BPF_REG_0);
+ regs[BPF_REG_0].btf = desc_btf;
+ regs[BPF_REG_0].type = PTR_TO_BTF_ID;
+ regs[BPF_REG_0].btf_id = ptr_type_id;
+ }
+
+ if (is_kfunc_ret_null(&meta)) {
+ regs[BPF_REG_0].type |= PTR_MAYBE_NULL;
+ /* For mark_ptr_or_null_reg, see 93c230e3f5bd6 */
+ regs[BPF_REG_0].id = ++env->id_gen;
+ }
+ mark_btf_func_reg_size(env, BPF_REG_0, sizeof(void *));
+ if (is_kfunc_acquire(&meta)) {
+ int id = acquire_reference_state(env, insn_idx);
+
+ if (id < 0)
+ return id;
+ if (is_kfunc_ret_null(&meta))
+ regs[BPF_REG_0].id = id;
+ regs[BPF_REG_0].ref_obj_id = id;
+ } else if (meta.func_id == special_kfunc_list[KF_bpf_rbtree_first]) {
+ ref_set_non_owning(env, &regs[BPF_REG_0]);
+ }
+
+ if (reg_may_point_to_spin_lock(&regs[BPF_REG_0]) && !regs[BPF_REG_0].id)
+ regs[BPF_REG_0].id = ++env->id_gen;
+ } else if (btf_type_is_void(t)) {
+ if (meta.btf == btf_vmlinux && btf_id_set_contains(&special_kfunc_set, meta.func_id)) {
+ if (meta.func_id == special_kfunc_list[KF_bpf_obj_drop_impl]) {
+ insn_aux->kptr_struct_meta =
+ btf_find_struct_meta(meta.arg_btf,
+ meta.arg_btf_id);
+ }
+ }
+ }
+
+ nargs = btf_type_vlen(meta.func_proto);
+ args = (const struct btf_param *)(meta.func_proto + 1);
+ for (i = 0; i < nargs; i++) {
+ u32 regno = i + 1;
+
+ t = btf_type_skip_modifiers(desc_btf, args[i].type, NULL);
+ if (btf_type_is_ptr(t))
+ mark_btf_func_reg_size(env, regno, sizeof(void *));
+ else
+ /* scalar. ensured by btf_check_kfunc_arg_match() */
+ mark_btf_func_reg_size(env, regno, t->size);
+ }
+
+ if (is_iter_next_kfunc(&meta)) {
+ err = process_iter_next_call(env, insn_idx, &meta);
+ if (err)
+ return err;
+ }
+
+ return 0;
+}
+
+static bool signed_add_overflows(s64 a, s64 b)
+{
+ /* Do the add in u64, where overflow is well-defined */
+ s64 res = (s64)((u64)a + (u64)b);
+
+ if (b < 0)
+ return res > a;
+ return res < a;
+}
+
+static bool signed_add32_overflows(s32 a, s32 b)
+{
+ /* Do the add in u32, where overflow is well-defined */
+ s32 res = (s32)((u32)a + (u32)b);
+
+ if (b < 0)
+ return res > a;
+ return res < a;
+}
+
+static bool signed_sub_overflows(s64 a, s64 b)
+{
+ /* Do the sub in u64, where overflow is well-defined */
+ s64 res = (s64)((u64)a - (u64)b);
+
+ if (b < 0)
+ return res < a;
+ return res > a;
+}
+
+static bool signed_sub32_overflows(s32 a, s32 b)
+{
+ /* Do the sub in u32, where overflow is well-defined */
+ s32 res = (s32)((u32)a - (u32)b);
+
+ if (b < 0)
+ return res < a;
+ return res > a;
+}
+
+static bool check_reg_sane_offset(struct bpf_verifier_env *env,
+ const struct bpf_reg_state *reg,
+ enum bpf_reg_type type)
+{
+ bool known = tnum_is_const(reg->var_off);
+ s64 val = reg->var_off.value;
+ s64 smin = reg->smin_value;
+
+ if (known && (val >= BPF_MAX_VAR_OFF || val <= -BPF_MAX_VAR_OFF)) {
+ verbose(env, "math between %s pointer and %lld is not allowed\n",
+ reg_type_str(env, type), val);
+ return false;
+ }
+
+ if (reg->off >= BPF_MAX_VAR_OFF || reg->off <= -BPF_MAX_VAR_OFF) {
+ verbose(env, "%s pointer offset %d is not allowed\n",
+ reg_type_str(env, type), reg->off);
+ return false;
+ }
+
+ if (smin == S64_MIN) {
+ verbose(env, "math between %s pointer and register with unbounded min value is not allowed\n",
+ reg_type_str(env, type));
+ return false;
+ }
+
+ if (smin >= BPF_MAX_VAR_OFF || smin <= -BPF_MAX_VAR_OFF) {
+ verbose(env, "value %lld makes %s pointer be out of bounds\n",
+ smin, reg_type_str(env, type));
+ return false;
+ }
+
+ return true;
+}
+
+enum {
+ REASON_BOUNDS = -1,
+ REASON_TYPE = -2,
+ REASON_PATHS = -3,
+ REASON_LIMIT = -4,
+ REASON_STACK = -5,
+};
+
+static int retrieve_ptr_limit(const struct bpf_reg_state *ptr_reg,
+ u32 *alu_limit, bool mask_to_left)
+{
+ u32 max = 0, ptr_limit = 0;
+
+ switch (ptr_reg->type) {
+ case PTR_TO_STACK:
+ /* Offset 0 is out-of-bounds, but acceptable start for the
+ * left direction, see BPF_REG_FP. Also, unknown scalar
+ * offset where we would need to deal with min/max bounds is
+ * currently prohibited for unprivileged.
+ */
+ max = MAX_BPF_STACK + mask_to_left;
+ ptr_limit = -(ptr_reg->var_off.value + ptr_reg->off);
+ break;
+ case PTR_TO_MAP_VALUE:
+ max = ptr_reg->map_ptr->value_size;
+ ptr_limit = (mask_to_left ?
+ ptr_reg->smin_value :
+ ptr_reg->umax_value) + ptr_reg->off;
+ break;
+ default:
+ return REASON_TYPE;
+ }
+
+ if (ptr_limit >= max)
+ return REASON_LIMIT;
+ *alu_limit = ptr_limit;
+ return 0;
+}
+
+static bool can_skip_alu_sanitation(const struct bpf_verifier_env *env,
+ const struct bpf_insn *insn)
+{
+ return env->bypass_spec_v1 || BPF_SRC(insn->code) == BPF_K;
+}
+
+static int update_alu_sanitation_state(struct bpf_insn_aux_data *aux,
+ u32 alu_state, u32 alu_limit)
+{
+ /* If we arrived here from different branches with different
+ * state or limits to sanitize, then this won't work.
+ */
+ if (aux->alu_state &&
+ (aux->alu_state != alu_state ||
+ aux->alu_limit != alu_limit))
+ return REASON_PATHS;
+
+ /* Corresponding fixup done in do_misc_fixups(). */
+ aux->alu_state = alu_state;
+ aux->alu_limit = alu_limit;
+ return 0;
+}
+
+static int sanitize_val_alu(struct bpf_verifier_env *env,
+ struct bpf_insn *insn)
+{
+ struct bpf_insn_aux_data *aux = cur_aux(env);
+
+ if (can_skip_alu_sanitation(env, insn))
+ return 0;
+
+ return update_alu_sanitation_state(aux, BPF_ALU_NON_POINTER, 0);
+}
+
+static bool sanitize_needed(u8 opcode)
+{
+ return opcode == BPF_ADD || opcode == BPF_SUB;
+}
+
+struct bpf_sanitize_info {
+ struct bpf_insn_aux_data aux;
+ bool mask_to_left;
+};
+
+static struct bpf_verifier_state *
+sanitize_speculative_path(struct bpf_verifier_env *env,
+ const struct bpf_insn *insn,
+ u32 next_idx, u32 curr_idx)
+{
+ struct bpf_verifier_state *branch;
+ struct bpf_reg_state *regs;
+
+ branch = push_stack(env, next_idx, curr_idx, true);
+ if (branch && insn) {
+ regs = branch->frame[branch->curframe]->regs;
+ if (BPF_SRC(insn->code) == BPF_K) {
+ mark_reg_unknown(env, regs, insn->dst_reg);
+ } else if (BPF_SRC(insn->code) == BPF_X) {
+ mark_reg_unknown(env, regs, insn->dst_reg);
+ mark_reg_unknown(env, regs, insn->src_reg);
+ }
+ }
+ return branch;
+}
+
+static int sanitize_ptr_alu(struct bpf_verifier_env *env,
+ struct bpf_insn *insn,
+ const struct bpf_reg_state *ptr_reg,
+ const struct bpf_reg_state *off_reg,
+ struct bpf_reg_state *dst_reg,
+ struct bpf_sanitize_info *info,
+ const bool commit_window)
+{
+ struct bpf_insn_aux_data *aux = commit_window ? cur_aux(env) : &info->aux;
+ struct bpf_verifier_state *vstate = env->cur_state;
+ bool off_is_imm = tnum_is_const(off_reg->var_off);
+ bool off_is_neg = off_reg->smin_value < 0;
+ bool ptr_is_dst_reg = ptr_reg == dst_reg;
+ u8 opcode = BPF_OP(insn->code);
+ u32 alu_state, alu_limit;
+ struct bpf_reg_state tmp;
+ bool ret;
+ int err;
+
+ if (can_skip_alu_sanitation(env, insn))
+ return 0;
+
+ /* We already marked aux for masking from non-speculative
+ * paths, thus we got here in the first place. We only care
+ * to explore bad access from here.
+ */
+ if (vstate->speculative)
+ goto do_sim;
+
+ if (!commit_window) {
+ if (!tnum_is_const(off_reg->var_off) &&
+ (off_reg->smin_value < 0) != (off_reg->smax_value < 0))
+ return REASON_BOUNDS;
+
+ info->mask_to_left = (opcode == BPF_ADD && off_is_neg) ||
+ (opcode == BPF_SUB && !off_is_neg);
+ }
+
+ err = retrieve_ptr_limit(ptr_reg, &alu_limit, info->mask_to_left);
+ if (err < 0)
+ return err;
+
+ if (commit_window) {
+ /* In commit phase we narrow the masking window based on
+ * the observed pointer move after the simulated operation.
+ */
+ alu_state = info->aux.alu_state;
+ alu_limit = abs(info->aux.alu_limit - alu_limit);
+ } else {
+ alu_state = off_is_neg ? BPF_ALU_NEG_VALUE : 0;
+ alu_state |= off_is_imm ? BPF_ALU_IMMEDIATE : 0;
+ alu_state |= ptr_is_dst_reg ?
+ BPF_ALU_SANITIZE_SRC : BPF_ALU_SANITIZE_DST;
+
+ /* Limit pruning on unknown scalars to enable deep search for
+ * potential masking differences from other program paths.
+ */
+ if (!off_is_imm)
+ env->explore_alu_limits = true;
+ }
+
+ err = update_alu_sanitation_state(aux, alu_state, alu_limit);
+ if (err < 0)
+ return err;
+do_sim:
+ /* If we're in commit phase, we're done here given we already
+ * pushed the truncated dst_reg into the speculative verification
+ * stack.
+ *
+ * Also, when register is a known constant, we rewrite register-based
+ * operation to immediate-based, and thus do not need masking (and as
+ * a consequence, do not need to simulate the zero-truncation either).
+ */
+ if (commit_window || off_is_imm)
+ return 0;
+
+ /* Simulate and find potential out-of-bounds access under
+ * speculative execution from truncation as a result of
+ * masking when off was not within expected range. If off
+ * sits in dst, then we temporarily need to move ptr there
+ * to simulate dst (== 0) +/-= ptr. Needed, for example,
+ * for cases where we use K-based arithmetic in one direction
+ * and truncated reg-based in the other in order to explore
+ * bad access.
+ */
+ if (!ptr_is_dst_reg) {
+ tmp = *dst_reg;
+ copy_register_state(dst_reg, ptr_reg);
+ }
+ ret = sanitize_speculative_path(env, NULL, env->insn_idx + 1,
+ env->insn_idx);
+ if (!ptr_is_dst_reg && ret)
+ *dst_reg = tmp;
+ return !ret ? REASON_STACK : 0;
+}
+
+static void sanitize_mark_insn_seen(struct bpf_verifier_env *env)
+{
+ struct bpf_verifier_state *vstate = env->cur_state;
+
+ /* If we simulate paths under speculation, we don't update the
+ * insn as 'seen' such that when we verify unreachable paths in
+ * the non-speculative domain, sanitize_dead_code() can still
+ * rewrite/sanitize them.
+ */
+ if (!vstate->speculative)
+ env->insn_aux_data[env->insn_idx].seen = env->pass_cnt;
+}
+
+static int sanitize_err(struct bpf_verifier_env *env,
+ const struct bpf_insn *insn, int reason,
+ const struct bpf_reg_state *off_reg,
+ const struct bpf_reg_state *dst_reg)
+{
+ static const char *err = "pointer arithmetic with it prohibited for !root";
+ const char *op = BPF_OP(insn->code) == BPF_ADD ? "add" : "sub";
+ u32 dst = insn->dst_reg, src = insn->src_reg;
+
+ switch (reason) {
+ case REASON_BOUNDS:
+ verbose(env, "R%d has unknown scalar with mixed signed bounds, %s\n",
+ off_reg == dst_reg ? dst : src, err);
+ break;
+ case REASON_TYPE:
+ verbose(env, "R%d has pointer with unsupported alu operation, %s\n",
+ off_reg == dst_reg ? src : dst, err);
+ break;
+ case REASON_PATHS:
+ verbose(env, "R%d tried to %s from different maps, paths or scalars, %s\n",
+ dst, op, err);
+ break;
+ case REASON_LIMIT:
+ verbose(env, "R%d tried to %s beyond pointer bounds, %s\n",
+ dst, op, err);
+ break;
+ case REASON_STACK:
+ verbose(env, "R%d could not be pushed for speculative verification, %s\n",
+ dst, err);
+ break;
+ default:
+ verbose(env, "verifier internal error: unknown reason (%d)\n",
+ reason);
+ break;
+ }
+
+ return -EACCES;
+}
+
+/* check that stack access falls within stack limits and that 'reg' doesn't
+ * have a variable offset.
+ *
+ * Variable offset is prohibited for unprivileged mode for simplicity since it
+ * requires corresponding support in Spectre masking for stack ALU. See also
+ * retrieve_ptr_limit().
+ *
+ *
+ * 'off' includes 'reg->off'.
+ */
+static int check_stack_access_for_ptr_arithmetic(
+ struct bpf_verifier_env *env,
+ int regno,
+ const struct bpf_reg_state *reg,
+ int off)
+{
+ if (!tnum_is_const(reg->var_off)) {
+ char tn_buf[48];
+
+ tnum_strn(tn_buf, sizeof(tn_buf), reg->var_off);
+ verbose(env, "R%d variable stack access prohibited for !root, var_off=%s off=%d\n",
+ regno, tn_buf, off);
+ return -EACCES;
+ }
+
+ if (off >= 0 || off < -MAX_BPF_STACK) {
+ verbose(env, "R%d stack pointer arithmetic goes out of range, "
+ "prohibited for !root; off=%d\n", regno, off);
+ return -EACCES;
+ }
+
+ return 0;
+}
+
+static int sanitize_check_bounds(struct bpf_verifier_env *env,
+ const struct bpf_insn *insn,
+ const struct bpf_reg_state *dst_reg)
+{
+ u32 dst = insn->dst_reg;
+
+ /* For unprivileged we require that resulting offset must be in bounds
+ * in order to be able to sanitize access later on.
+ */
+ if (env->bypass_spec_v1)
+ return 0;
+
+ switch (dst_reg->type) {
+ case PTR_TO_STACK:
+ if (check_stack_access_for_ptr_arithmetic(env, dst, dst_reg,
+ dst_reg->off + dst_reg->var_off.value))
+ return -EACCES;
+ break;
+ case PTR_TO_MAP_VALUE:
+ if (check_map_access(env, dst, dst_reg->off, 1, false, ACCESS_HELPER)) {
+ verbose(env, "R%d pointer arithmetic of map value goes out of range, "
+ "prohibited for !root\n", dst);
+ return -EACCES;
+ }
+ break;
+ default:
+ break;
+ }
+
+ return 0;
+}
+
+/* Handles arithmetic on a pointer and a scalar: computes new min/max and var_off.
+ * Caller should also handle BPF_MOV case separately.
+ * If we return -EACCES, caller may want to try again treating pointer as a
+ * scalar. So we only emit a diagnostic if !env->allow_ptr_leaks.
+ */
+static int adjust_ptr_min_max_vals(struct bpf_verifier_env *env,
+ struct bpf_insn *insn,
+ const struct bpf_reg_state *ptr_reg,
+ const struct bpf_reg_state *off_reg)
+{
+ struct bpf_verifier_state *vstate = env->cur_state;
+ struct bpf_func_state *state = vstate->frame[vstate->curframe];
+ struct bpf_reg_state *regs = state->regs, *dst_reg;
+ bool known = tnum_is_const(off_reg->var_off);
+ s64 smin_val = off_reg->smin_value, smax_val = off_reg->smax_value,
+ smin_ptr = ptr_reg->smin_value, smax_ptr = ptr_reg->smax_value;
+ u64 umin_val = off_reg->umin_value, umax_val = off_reg->umax_value,
+ umin_ptr = ptr_reg->umin_value, umax_ptr = ptr_reg->umax_value;
+ struct bpf_sanitize_info info = {};
+ u8 opcode = BPF_OP(insn->code);
+ u32 dst = insn->dst_reg;
+ int ret;
+
+ dst_reg = &regs[dst];
+
+ if ((known && (smin_val != smax_val || umin_val != umax_val)) ||
+ smin_val > smax_val || umin_val > umax_val) {
+ /* Taint dst register if offset had invalid bounds derived from
+ * e.g. dead branches.
+ */
+ __mark_reg_unknown(env, dst_reg);
+ return 0;
+ }
+
+ if (BPF_CLASS(insn->code) != BPF_ALU64) {
+ /* 32-bit ALU ops on pointers produce (meaningless) scalars */
+ if (opcode == BPF_SUB && env->allow_ptr_leaks) {
+ __mark_reg_unknown(env, dst_reg);
+ return 0;
+ }
+
+ verbose(env,
+ "R%d 32-bit pointer arithmetic prohibited\n",
+ dst);
+ return -EACCES;
+ }
+
+ if (ptr_reg->type & PTR_MAYBE_NULL) {
+ verbose(env, "R%d pointer arithmetic on %s prohibited, null-check it first\n",
+ dst, reg_type_str(env, ptr_reg->type));
+ return -EACCES;
+ }
+
+ switch (base_type(ptr_reg->type)) {
+ case PTR_TO_FLOW_KEYS:
+ if (known)
+ break;
+ fallthrough;
+ case CONST_PTR_TO_MAP:
+ /* smin_val represents the known value */
+ if (known && smin_val == 0 && opcode == BPF_ADD)
+ break;
+ fallthrough;
+ case PTR_TO_PACKET_END:
+ case PTR_TO_SOCKET:
+ case PTR_TO_SOCK_COMMON:
+ case PTR_TO_TCP_SOCK:
+ case PTR_TO_XDP_SOCK:
+ verbose(env, "R%d pointer arithmetic on %s prohibited\n",
+ dst, reg_type_str(env, ptr_reg->type));
+ return -EACCES;
+ default:
+ break;
+ }
+
+ /* In case of 'scalar += pointer', dst_reg inherits pointer type and id.
+ * The id may be overwritten later if we create a new variable offset.
+ */
+ dst_reg->type = ptr_reg->type;
+ dst_reg->id = ptr_reg->id;
+
+ if (!check_reg_sane_offset(env, off_reg, ptr_reg->type) ||
+ !check_reg_sane_offset(env, ptr_reg, ptr_reg->type))
+ return -EINVAL;
+
+ /* pointer types do not carry 32-bit bounds at the moment. */
+ __mark_reg32_unbounded(dst_reg);
+
+ if (sanitize_needed(opcode)) {
+ ret = sanitize_ptr_alu(env, insn, ptr_reg, off_reg, dst_reg,
+ &info, false);
+ if (ret < 0)
+ return sanitize_err(env, insn, ret, off_reg, dst_reg);
+ }
+
+ switch (opcode) {
+ case BPF_ADD:
+ /* We can take a fixed offset as long as it doesn't overflow
+ * the s32 'off' field
+ */
+ if (known && (ptr_reg->off + smin_val ==
+ (s64)(s32)(ptr_reg->off + smin_val))) {
+ /* pointer += K. Accumulate it into fixed offset */
+ dst_reg->smin_value = smin_ptr;
+ dst_reg->smax_value = smax_ptr;
+ dst_reg->umin_value = umin_ptr;
+ dst_reg->umax_value = umax_ptr;
+ dst_reg->var_off = ptr_reg->var_off;
+ dst_reg->off = ptr_reg->off + smin_val;
+ dst_reg->raw = ptr_reg->raw;
+ break;
+ }
+ /* A new variable offset is created. Note that off_reg->off
+ * == 0, since it's a scalar.
+ * dst_reg gets the pointer type and since some positive
+ * integer value was added to the pointer, give it a new 'id'
+ * if it's a PTR_TO_PACKET.
+ * this creates a new 'base' pointer, off_reg (variable) gets
+ * added into the variable offset, and we copy the fixed offset
+ * from ptr_reg.
+ */
+ if (signed_add_overflows(smin_ptr, smin_val) ||
+ signed_add_overflows(smax_ptr, smax_val)) {
+ dst_reg->smin_value = S64_MIN;
+ dst_reg->smax_value = S64_MAX;
+ } else {
+ dst_reg->smin_value = smin_ptr + smin_val;
+ dst_reg->smax_value = smax_ptr + smax_val;
+ }
+ if (umin_ptr + umin_val < umin_ptr ||
+ umax_ptr + umax_val < umax_ptr) {
+ dst_reg->umin_value = 0;
+ dst_reg->umax_value = U64_MAX;
+ } else {
+ dst_reg->umin_value = umin_ptr + umin_val;
+ dst_reg->umax_value = umax_ptr + umax_val;
+ }
+ dst_reg->var_off = tnum_add(ptr_reg->var_off, off_reg->var_off);
+ dst_reg->off = ptr_reg->off;
+ dst_reg->raw = ptr_reg->raw;
+ if (reg_is_pkt_pointer(ptr_reg)) {
+ dst_reg->id = ++env->id_gen;
+ /* something was added to pkt_ptr, set range to zero */
+ memset(&dst_reg->raw, 0, sizeof(dst_reg->raw));
+ }
+ break;
+ case BPF_SUB:
+ if (dst_reg == off_reg) {
+ /* scalar -= pointer. Creates an unknown scalar */
+ verbose(env, "R%d tried to subtract pointer from scalar\n",
+ dst);
+ return -EACCES;
+ }
+ /* We don't allow subtraction from FP, because (according to
+ * test_verifier.c test "invalid fp arithmetic", JITs might not
+ * be able to deal with it.
+ */
+ if (ptr_reg->type == PTR_TO_STACK) {
+ verbose(env, "R%d subtraction from stack pointer prohibited\n",
+ dst);
+ return -EACCES;
+ }
+ if (known && (ptr_reg->off - smin_val ==
+ (s64)(s32)(ptr_reg->off - smin_val))) {
+ /* pointer -= K. Subtract it from fixed offset */
+ dst_reg->smin_value = smin_ptr;
+ dst_reg->smax_value = smax_ptr;
+ dst_reg->umin_value = umin_ptr;
+ dst_reg->umax_value = umax_ptr;
+ dst_reg->var_off = ptr_reg->var_off;
+ dst_reg->id = ptr_reg->id;
+ dst_reg->off = ptr_reg->off - smin_val;
+ dst_reg->raw = ptr_reg->raw;
+ break;
+ }
+ /* A new variable offset is created. If the subtrahend is known
+ * nonnegative, then any reg->range we had before is still good.
+ */
+ if (signed_sub_overflows(smin_ptr, smax_val) ||
+ signed_sub_overflows(smax_ptr, smin_val)) {
+ /* Overflow possible, we know nothing */
+ dst_reg->smin_value = S64_MIN;
+ dst_reg->smax_value = S64_MAX;
+ } else {
+ dst_reg->smin_value = smin_ptr - smax_val;
+ dst_reg->smax_value = smax_ptr - smin_val;
+ }
+ if (umin_ptr < umax_val) {
+ /* Overflow possible, we know nothing */
+ dst_reg->umin_value = 0;
+ dst_reg->umax_value = U64_MAX;
+ } else {
+ /* Cannot overflow (as long as bounds are consistent) */
+ dst_reg->umin_value = umin_ptr - umax_val;
+ dst_reg->umax_value = umax_ptr - umin_val;
+ }
+ dst_reg->var_off = tnum_sub(ptr_reg->var_off, off_reg->var_off);
+ dst_reg->off = ptr_reg->off;
+ dst_reg->raw = ptr_reg->raw;
+ if (reg_is_pkt_pointer(ptr_reg)) {
+ dst_reg->id = ++env->id_gen;
+ /* something was added to pkt_ptr, set range to zero */
+ if (smin_val < 0)
+ memset(&dst_reg->raw, 0, sizeof(dst_reg->raw));
+ }
+ break;
+ case BPF_AND:
+ case BPF_OR:
+ case BPF_XOR:
+ /* bitwise ops on pointers are troublesome, prohibit. */
+ verbose(env, "R%d bitwise operator %s on pointer prohibited\n",
+ dst, bpf_alu_string[opcode >> 4]);
+ return -EACCES;
+ default:
+ /* other operators (e.g. MUL,LSH) produce non-pointer results */
+ verbose(env, "R%d pointer arithmetic with %s operator prohibited\n",
+ dst, bpf_alu_string[opcode >> 4]);
+ return -EACCES;
+ }
+
+ if (!check_reg_sane_offset(env, dst_reg, ptr_reg->type))
+ return -EINVAL;
+ reg_bounds_sync(dst_reg);
+ if (sanitize_check_bounds(env, insn, dst_reg) < 0)
+ return -EACCES;
+ if (sanitize_needed(opcode)) {
+ ret = sanitize_ptr_alu(env, insn, dst_reg, off_reg, dst_reg,
+ &info, true);
+ if (ret < 0)
+ return sanitize_err(env, insn, ret, off_reg, dst_reg);
+ }
+
+ return 0;
+}
+
+static void scalar32_min_max_add(struct bpf_reg_state *dst_reg,
+ struct bpf_reg_state *src_reg)
+{
+ s32 smin_val = src_reg->s32_min_value;
+ s32 smax_val = src_reg->s32_max_value;
+ u32 umin_val = src_reg->u32_min_value;
+ u32 umax_val = src_reg->u32_max_value;
+
+ if (signed_add32_overflows(dst_reg->s32_min_value, smin_val) ||
+ signed_add32_overflows(dst_reg->s32_max_value, smax_val)) {
+ dst_reg->s32_min_value = S32_MIN;
+ dst_reg->s32_max_value = S32_MAX;
+ } else {
+ dst_reg->s32_min_value += smin_val;
+ dst_reg->s32_max_value += smax_val;
+ }
+ if (dst_reg->u32_min_value + umin_val < umin_val ||
+ dst_reg->u32_max_value + umax_val < umax_val) {
+ dst_reg->u32_min_value = 0;
+ dst_reg->u32_max_value = U32_MAX;
+ } else {
+ dst_reg->u32_min_value += umin_val;
+ dst_reg->u32_max_value += umax_val;
+ }
+}
+
+static void scalar_min_max_add(struct bpf_reg_state *dst_reg,
+ struct bpf_reg_state *src_reg)
+{
+ s64 smin_val = src_reg->smin_value;
+ s64 smax_val = src_reg->smax_value;
+ u64 umin_val = src_reg->umin_value;
+ u64 umax_val = src_reg->umax_value;
+
+ if (signed_add_overflows(dst_reg->smin_value, smin_val) ||
+ signed_add_overflows(dst_reg->smax_value, smax_val)) {
+ dst_reg->smin_value = S64_MIN;
+ dst_reg->smax_value = S64_MAX;
+ } else {
+ dst_reg->smin_value += smin_val;
+ dst_reg->smax_value += smax_val;
+ }
+ if (dst_reg->umin_value + umin_val < umin_val ||
+ dst_reg->umax_value + umax_val < umax_val) {
+ dst_reg->umin_value = 0;
+ dst_reg->umax_value = U64_MAX;
+ } else {
+ dst_reg->umin_value += umin_val;
+ dst_reg->umax_value += umax_val;
+ }
+}
+
+static void scalar32_min_max_sub(struct bpf_reg_state *dst_reg,
+ struct bpf_reg_state *src_reg)
+{
+ s32 smin_val = src_reg->s32_min_value;
+ s32 smax_val = src_reg->s32_max_value;
+ u32 umin_val = src_reg->u32_min_value;
+ u32 umax_val = src_reg->u32_max_value;
+
+ if (signed_sub32_overflows(dst_reg->s32_min_value, smax_val) ||
+ signed_sub32_overflows(dst_reg->s32_max_value, smin_val)) {
+ /* Overflow possible, we know nothing */
+ dst_reg->s32_min_value = S32_MIN;
+ dst_reg->s32_max_value = S32_MAX;
+ } else {
+ dst_reg->s32_min_value -= smax_val;
+ dst_reg->s32_max_value -= smin_val;
+ }
+ if (dst_reg->u32_min_value < umax_val) {
+ /* Overflow possible, we know nothing */
+ dst_reg->u32_min_value = 0;
+ dst_reg->u32_max_value = U32_MAX;
+ } else {
+ /* Cannot overflow (as long as bounds are consistent) */
+ dst_reg->u32_min_value -= umax_val;
+ dst_reg->u32_max_value -= umin_val;
+ }
+}
+
+static void scalar_min_max_sub(struct bpf_reg_state *dst_reg,
+ struct bpf_reg_state *src_reg)
+{
+ s64 smin_val = src_reg->smin_value;
+ s64 smax_val = src_reg->smax_value;
+ u64 umin_val = src_reg->umin_value;
+ u64 umax_val = src_reg->umax_value;
+
+ if (signed_sub_overflows(dst_reg->smin_value, smax_val) ||
+ signed_sub_overflows(dst_reg->smax_value, smin_val)) {
+ /* Overflow possible, we know nothing */
+ dst_reg->smin_value = S64_MIN;
+ dst_reg->smax_value = S64_MAX;
+ } else {
+ dst_reg->smin_value -= smax_val;
+ dst_reg->smax_value -= smin_val;
+ }
+ if (dst_reg->umin_value < umax_val) {
+ /* Overflow possible, we know nothing */
+ dst_reg->umin_value = 0;
+ dst_reg->umax_value = U64_MAX;
+ } else {
+ /* Cannot overflow (as long as bounds are consistent) */
+ dst_reg->umin_value -= umax_val;
+ dst_reg->umax_value -= umin_val;
+ }
+}
+
+static void scalar32_min_max_mul(struct bpf_reg_state *dst_reg,
+ struct bpf_reg_state *src_reg)
+{
+ s32 smin_val = src_reg->s32_min_value;
+ u32 umin_val = src_reg->u32_min_value;
+ u32 umax_val = src_reg->u32_max_value;
+
+ if (smin_val < 0 || dst_reg->s32_min_value < 0) {
+ /* Ain't nobody got time to multiply that sign */
+ __mark_reg32_unbounded(dst_reg);
+ return;
+ }
+ /* Both values are positive, so we can work with unsigned and
+ * copy the result to signed (unless it exceeds S32_MAX).
+ */
+ if (umax_val > U16_MAX || dst_reg->u32_max_value > U16_MAX) {
+ /* Potential overflow, we know nothing */
+ __mark_reg32_unbounded(dst_reg);
+ return;
+ }
+ dst_reg->u32_min_value *= umin_val;
+ dst_reg->u32_max_value *= umax_val;
+ if (dst_reg->u32_max_value > S32_MAX) {
+ /* Overflow possible, we know nothing */
+ dst_reg->s32_min_value = S32_MIN;
+ dst_reg->s32_max_value = S32_MAX;
+ } else {
+ dst_reg->s32_min_value = dst_reg->u32_min_value;
+ dst_reg->s32_max_value = dst_reg->u32_max_value;
+ }
+}
+
+static void scalar_min_max_mul(struct bpf_reg_state *dst_reg,
+ struct bpf_reg_state *src_reg)
+{
+ s64 smin_val = src_reg->smin_value;
+ u64 umin_val = src_reg->umin_value;
+ u64 umax_val = src_reg->umax_value;
+
+ if (smin_val < 0 || dst_reg->smin_value < 0) {
+ /* Ain't nobody got time to multiply that sign */
+ __mark_reg64_unbounded(dst_reg);
+ return;
+ }
+ /* Both values are positive, so we can work with unsigned and
+ * copy the result to signed (unless it exceeds S64_MAX).
+ */
+ if (umax_val > U32_MAX || dst_reg->umax_value > U32_MAX) {
+ /* Potential overflow, we know nothing */
+ __mark_reg64_unbounded(dst_reg);
+ return;
+ }
+ dst_reg->umin_value *= umin_val;
+ dst_reg->umax_value *= umax_val;
+ if (dst_reg->umax_value > S64_MAX) {
+ /* Overflow possible, we know nothing */
+ dst_reg->smin_value = S64_MIN;
+ dst_reg->smax_value = S64_MAX;
+ } else {
+ dst_reg->smin_value = dst_reg->umin_value;
+ dst_reg->smax_value = dst_reg->umax_value;
+ }
+}
+
+static void scalar32_min_max_and(struct bpf_reg_state *dst_reg,
+ struct bpf_reg_state *src_reg)
+{
+ bool src_known = tnum_subreg_is_const(src_reg->var_off);
+ bool dst_known = tnum_subreg_is_const(dst_reg->var_off);
+ struct tnum var32_off = tnum_subreg(dst_reg->var_off);
+ s32 smin_val = src_reg->s32_min_value;
+ u32 umax_val = src_reg->u32_max_value;
+
+ if (src_known && dst_known) {
+ __mark_reg32_known(dst_reg, var32_off.value);
+ return;
+ }
+
+ /* We get our minimum from the var_off, since that's inherently
+ * bitwise. Our maximum is the minimum of the operands' maxima.
+ */
+ dst_reg->u32_min_value = var32_off.value;
+ dst_reg->u32_max_value = min(dst_reg->u32_max_value, umax_val);
+ if (dst_reg->s32_min_value < 0 || smin_val < 0) {
+ /* Lose signed bounds when ANDing negative numbers,
+ * ain't nobody got time for that.
+ */
+ dst_reg->s32_min_value = S32_MIN;
+ dst_reg->s32_max_value = S32_MAX;
+ } else {
+ /* ANDing two positives gives a positive, so safe to
+ * cast result into s64.
+ */
+ dst_reg->s32_min_value = dst_reg->u32_min_value;
+ dst_reg->s32_max_value = dst_reg->u32_max_value;
+ }
+}
+
+static void scalar_min_max_and(struct bpf_reg_state *dst_reg,
+ struct bpf_reg_state *src_reg)
+{
+ bool src_known = tnum_is_const(src_reg->var_off);
+ bool dst_known = tnum_is_const(dst_reg->var_off);
+ s64 smin_val = src_reg->smin_value;
+ u64 umax_val = src_reg->umax_value;
+
+ if (src_known && dst_known) {
+ __mark_reg_known(dst_reg, dst_reg->var_off.value);
+ return;
+ }
+
+ /* We get our minimum from the var_off, since that's inherently
+ * bitwise. Our maximum is the minimum of the operands' maxima.
+ */
+ dst_reg->umin_value = dst_reg->var_off.value;
+ dst_reg->umax_value = min(dst_reg->umax_value, umax_val);
+ if (dst_reg->smin_value < 0 || smin_val < 0) {
+ /* Lose signed bounds when ANDing negative numbers,
+ * ain't nobody got time for that.
+ */
+ dst_reg->smin_value = S64_MIN;
+ dst_reg->smax_value = S64_MAX;
+ } else {
+ /* ANDing two positives gives a positive, so safe to
+ * cast result into s64.
+ */
+ dst_reg->smin_value = dst_reg->umin_value;
+ dst_reg->smax_value = dst_reg->umax_value;
+ }
+ /* We may learn something more from the var_off */
+ __update_reg_bounds(dst_reg);
+}
+
+static void scalar32_min_max_or(struct bpf_reg_state *dst_reg,
+ struct bpf_reg_state *src_reg)
+{
+ bool src_known = tnum_subreg_is_const(src_reg->var_off);
+ bool dst_known = tnum_subreg_is_const(dst_reg->var_off);
+ struct tnum var32_off = tnum_subreg(dst_reg->var_off);
+ s32 smin_val = src_reg->s32_min_value;
+ u32 umin_val = src_reg->u32_min_value;
+
+ if (src_known && dst_known) {
+ __mark_reg32_known(dst_reg, var32_off.value);
+ return;
+ }
+
+ /* We get our maximum from the var_off, and our minimum is the
+ * maximum of the operands' minima
+ */
+ dst_reg->u32_min_value = max(dst_reg->u32_min_value, umin_val);
+ dst_reg->u32_max_value = var32_off.value | var32_off.mask;
+ if (dst_reg->s32_min_value < 0 || smin_val < 0) {
+ /* Lose signed bounds when ORing negative numbers,
+ * ain't nobody got time for that.
+ */
+ dst_reg->s32_min_value = S32_MIN;
+ dst_reg->s32_max_value = S32_MAX;
+ } else {
+ /* ORing two positives gives a positive, so safe to
+ * cast result into s64.
+ */
+ dst_reg->s32_min_value = dst_reg->u32_min_value;
+ dst_reg->s32_max_value = dst_reg->u32_max_value;
+ }
+}
+
+static void scalar_min_max_or(struct bpf_reg_state *dst_reg,
+ struct bpf_reg_state *src_reg)
+{
+ bool src_known = tnum_is_const(src_reg->var_off);
+ bool dst_known = tnum_is_const(dst_reg->var_off);
+ s64 smin_val = src_reg->smin_value;
+ u64 umin_val = src_reg->umin_value;
+
+ if (src_known && dst_known) {
+ __mark_reg_known(dst_reg, dst_reg->var_off.value);
+ return;
+ }
+
+ /* We get our maximum from the var_off, and our minimum is the
+ * maximum of the operands' minima
+ */
+ dst_reg->umin_value = max(dst_reg->umin_value, umin_val);
+ dst_reg->umax_value = dst_reg->var_off.value | dst_reg->var_off.mask;
+ if (dst_reg->smin_value < 0 || smin_val < 0) {
+ /* Lose signed bounds when ORing negative numbers,
+ * ain't nobody got time for that.
+ */
+ dst_reg->smin_value = S64_MIN;
+ dst_reg->smax_value = S64_MAX;
+ } else {
+ /* ORing two positives gives a positive, so safe to
+ * cast result into s64.
+ */
+ dst_reg->smin_value = dst_reg->umin_value;
+ dst_reg->smax_value = dst_reg->umax_value;
+ }
+ /* We may learn something more from the var_off */
+ __update_reg_bounds(dst_reg);
+}
+
+static void scalar32_min_max_xor(struct bpf_reg_state *dst_reg,
+ struct bpf_reg_state *src_reg)
+{
+ bool src_known = tnum_subreg_is_const(src_reg->var_off);
+ bool dst_known = tnum_subreg_is_const(dst_reg->var_off);
+ struct tnum var32_off = tnum_subreg(dst_reg->var_off);
+ s32 smin_val = src_reg->s32_min_value;
+
+ if (src_known && dst_known) {
+ __mark_reg32_known(dst_reg, var32_off.value);
+ return;
+ }
+
+ /* We get both minimum and maximum from the var32_off. */
+ dst_reg->u32_min_value = var32_off.value;
+ dst_reg->u32_max_value = var32_off.value | var32_off.mask;
+
+ if (dst_reg->s32_min_value >= 0 && smin_val >= 0) {
+ /* XORing two positive sign numbers gives a positive,
+ * so safe to cast u32 result into s32.
+ */
+ dst_reg->s32_min_value = dst_reg->u32_min_value;
+ dst_reg->s32_max_value = dst_reg->u32_max_value;
+ } else {
+ dst_reg->s32_min_value = S32_MIN;
+ dst_reg->s32_max_value = S32_MAX;
+ }
+}
+
+static void scalar_min_max_xor(struct bpf_reg_state *dst_reg,
+ struct bpf_reg_state *src_reg)
+{
+ bool src_known = tnum_is_const(src_reg->var_off);
+ bool dst_known = tnum_is_const(dst_reg->var_off);
+ s64 smin_val = src_reg->smin_value;
+
+ if (src_known && dst_known) {
+ /* dst_reg->var_off.value has been updated earlier */
+ __mark_reg_known(dst_reg, dst_reg->var_off.value);
+ return;
+ }
+
+ /* We get both minimum and maximum from the var_off. */
+ dst_reg->umin_value = dst_reg->var_off.value;
+ dst_reg->umax_value = dst_reg->var_off.value | dst_reg->var_off.mask;
+
+ if (dst_reg->smin_value >= 0 && smin_val >= 0) {
+ /* XORing two positive sign numbers gives a positive,
+ * so safe to cast u64 result into s64.
+ */
+ dst_reg->smin_value = dst_reg->umin_value;
+ dst_reg->smax_value = dst_reg->umax_value;
+ } else {
+ dst_reg->smin_value = S64_MIN;
+ dst_reg->smax_value = S64_MAX;
+ }
+
+ __update_reg_bounds(dst_reg);
+}
+
+static void __scalar32_min_max_lsh(struct bpf_reg_state *dst_reg,
+ u64 umin_val, u64 umax_val)
+{
+ /* We lose all sign bit information (except what we can pick
+ * up from var_off)
+ */
+ dst_reg->s32_min_value = S32_MIN;
+ dst_reg->s32_max_value = S32_MAX;
+ /* If we might shift our top bit out, then we know nothing */
+ if (umax_val > 31 || dst_reg->u32_max_value > 1ULL << (31 - umax_val)) {
+ dst_reg->u32_min_value = 0;
+ dst_reg->u32_max_value = U32_MAX;
+ } else {
+ dst_reg->u32_min_value <<= umin_val;
+ dst_reg->u32_max_value <<= umax_val;
+ }
+}
+
+static void scalar32_min_max_lsh(struct bpf_reg_state *dst_reg,
+ struct bpf_reg_state *src_reg)
+{
+ u32 umax_val = src_reg->u32_max_value;
+ u32 umin_val = src_reg->u32_min_value;
+ /* u32 alu operation will zext upper bits */
+ struct tnum subreg = tnum_subreg(dst_reg->var_off);
+
+ __scalar32_min_max_lsh(dst_reg, umin_val, umax_val);
+ dst_reg->var_off = tnum_subreg(tnum_lshift(subreg, umin_val));
+ /* Not required but being careful mark reg64 bounds as unknown so
+ * that we are forced to pick them up from tnum and zext later and
+ * if some path skips this step we are still safe.
+ */
+ __mark_reg64_unbounded(dst_reg);
+ __update_reg32_bounds(dst_reg);
+}
+
+static void __scalar64_min_max_lsh(struct bpf_reg_state *dst_reg,
+ u64 umin_val, u64 umax_val)
+{
+ /* Special case <<32 because it is a common compiler pattern to sign
+ * extend subreg by doing <<32 s>>32. In this case if 32bit bounds are
+ * positive we know this shift will also be positive so we can track
+ * bounds correctly. Otherwise we lose all sign bit information except
+ * what we can pick up from var_off. Perhaps we can generalize this
+ * later to shifts of any length.
+ */
+ if (umin_val == 32 && umax_val == 32 && dst_reg->s32_max_value >= 0)
+ dst_reg->smax_value = (s64)dst_reg->s32_max_value << 32;
+ else
+ dst_reg->smax_value = S64_MAX;
+
+ if (umin_val == 32 && umax_val == 32 && dst_reg->s32_min_value >= 0)
+ dst_reg->smin_value = (s64)dst_reg->s32_min_value << 32;
+ else
+ dst_reg->smin_value = S64_MIN;
+
+ /* If we might shift our top bit out, then we know nothing */
+ if (dst_reg->umax_value > 1ULL << (63 - umax_val)) {
+ dst_reg->umin_value = 0;
+ dst_reg->umax_value = U64_MAX;
+ } else {
+ dst_reg->umin_value <<= umin_val;
+ dst_reg->umax_value <<= umax_val;
+ }
+}
+
+static void scalar_min_max_lsh(struct bpf_reg_state *dst_reg,
+ struct bpf_reg_state *src_reg)
+{
+ u64 umax_val = src_reg->umax_value;
+ u64 umin_val = src_reg->umin_value;
+
+ /* scalar64 calc uses 32bit unshifted bounds so must be called first */
+ __scalar64_min_max_lsh(dst_reg, umin_val, umax_val);
+ __scalar32_min_max_lsh(dst_reg, umin_val, umax_val);
+
+ dst_reg->var_off = tnum_lshift(dst_reg->var_off, umin_val);
+ /* We may learn something more from the var_off */
+ __update_reg_bounds(dst_reg);
+}
+
+static void scalar32_min_max_rsh(struct bpf_reg_state *dst_reg,
+ struct bpf_reg_state *src_reg)
+{
+ struct tnum subreg = tnum_subreg(dst_reg->var_off);
+ u32 umax_val = src_reg->u32_max_value;
+ u32 umin_val = src_reg->u32_min_value;
+
+ /* BPF_RSH is an unsigned shift. If the value in dst_reg might
+ * be negative, then either:
+ * 1) src_reg might be zero, so the sign bit of the result is
+ * unknown, so we lose our signed bounds
+ * 2) it's known negative, thus the unsigned bounds capture the
+ * signed bounds
+ * 3) the signed bounds cross zero, so they tell us nothing
+ * about the result
+ * If the value in dst_reg is known nonnegative, then again the
+ * unsigned bounds capture the signed bounds.
+ * Thus, in all cases it suffices to blow away our signed bounds
+ * and rely on inferring new ones from the unsigned bounds and
+ * var_off of the result.
+ */
+ dst_reg->s32_min_value = S32_MIN;
+ dst_reg->s32_max_value = S32_MAX;
+
+ dst_reg->var_off = tnum_rshift(subreg, umin_val);
+ dst_reg->u32_min_value >>= umax_val;
+ dst_reg->u32_max_value >>= umin_val;
+
+ __mark_reg64_unbounded(dst_reg);
+ __update_reg32_bounds(dst_reg);
+}
+
+static void scalar_min_max_rsh(struct bpf_reg_state *dst_reg,
+ struct bpf_reg_state *src_reg)
+{
+ u64 umax_val = src_reg->umax_value;
+ u64 umin_val = src_reg->umin_value;
+
+ /* BPF_RSH is an unsigned shift. If the value in dst_reg might
+ * be negative, then either:
+ * 1) src_reg might be zero, so the sign bit of the result is
+ * unknown, so we lose our signed bounds
+ * 2) it's known negative, thus the unsigned bounds capture the
+ * signed bounds
+ * 3) the signed bounds cross zero, so they tell us nothing
+ * about the result
+ * If the value in dst_reg is known nonnegative, then again the
+ * unsigned bounds capture the signed bounds.
+ * Thus, in all cases it suffices to blow away our signed bounds
+ * and rely on inferring new ones from the unsigned bounds and
+ * var_off of the result.
+ */
+ dst_reg->smin_value = S64_MIN;
+ dst_reg->smax_value = S64_MAX;
+ dst_reg->var_off = tnum_rshift(dst_reg->var_off, umin_val);
+ dst_reg->umin_value >>= umax_val;
+ dst_reg->umax_value >>= umin_val;
+
+ /* Its not easy to operate on alu32 bounds here because it depends
+ * on bits being shifted in. Take easy way out and mark unbounded
+ * so we can recalculate later from tnum.
+ */
+ __mark_reg32_unbounded(dst_reg);
+ __update_reg_bounds(dst_reg);
+}
+
+static void scalar32_min_max_arsh(struct bpf_reg_state *dst_reg,
+ struct bpf_reg_state *src_reg)
+{
+ u64 umin_val = src_reg->u32_min_value;
+
+ /* Upon reaching here, src_known is true and
+ * umax_val is equal to umin_val.
+ */
+ dst_reg->s32_min_value = (u32)(((s32)dst_reg->s32_min_value) >> umin_val);
+ dst_reg->s32_max_value = (u32)(((s32)dst_reg->s32_max_value) >> umin_val);
+
+ dst_reg->var_off = tnum_arshift(tnum_subreg(dst_reg->var_off), umin_val, 32);
+
+ /* blow away the dst_reg umin_value/umax_value and rely on
+ * dst_reg var_off to refine the result.
+ */
+ dst_reg->u32_min_value = 0;
+ dst_reg->u32_max_value = U32_MAX;
+
+ __mark_reg64_unbounded(dst_reg);
+ __update_reg32_bounds(dst_reg);
+}
+
+static void scalar_min_max_arsh(struct bpf_reg_state *dst_reg,
+ struct bpf_reg_state *src_reg)
+{
+ u64 umin_val = src_reg->umin_value;
+
+ /* Upon reaching here, src_known is true and umax_val is equal
+ * to umin_val.
+ */
+ dst_reg->smin_value >>= umin_val;
+ dst_reg->smax_value >>= umin_val;
+
+ dst_reg->var_off = tnum_arshift(dst_reg->var_off, umin_val, 64);
+
+ /* blow away the dst_reg umin_value/umax_value and rely on
+ * dst_reg var_off to refine the result.
+ */
+ dst_reg->umin_value = 0;
+ dst_reg->umax_value = U64_MAX;
+
+ /* Its not easy to operate on alu32 bounds here because it depends
+ * on bits being shifted in from upper 32-bits. Take easy way out
+ * and mark unbounded so we can recalculate later from tnum.
+ */
+ __mark_reg32_unbounded(dst_reg);
+ __update_reg_bounds(dst_reg);
+}
+
+/* WARNING: This function does calculations on 64-bit values, but the actual
+ * execution may occur on 32-bit values. Therefore, things like bitshifts
+ * need extra checks in the 32-bit case.
+ */
+static int adjust_scalar_min_max_vals(struct bpf_verifier_env *env,
+ struct bpf_insn *insn,
+ struct bpf_reg_state *dst_reg,
+ struct bpf_reg_state src_reg)
+{
+ struct bpf_reg_state *regs = cur_regs(env);
+ u8 opcode = BPF_OP(insn->code);
+ bool src_known;
+ s64 smin_val, smax_val;
+ u64 umin_val, umax_val;
+ s32 s32_min_val, s32_max_val;
+ u32 u32_min_val, u32_max_val;
+ u64 insn_bitness = (BPF_CLASS(insn->code) == BPF_ALU64) ? 64 : 32;
+ bool alu32 = (BPF_CLASS(insn->code) != BPF_ALU64);
+ int ret;
+
+ smin_val = src_reg.smin_value;
+ smax_val = src_reg.smax_value;
+ umin_val = src_reg.umin_value;
+ umax_val = src_reg.umax_value;
+
+ s32_min_val = src_reg.s32_min_value;
+ s32_max_val = src_reg.s32_max_value;
+ u32_min_val = src_reg.u32_min_value;
+ u32_max_val = src_reg.u32_max_value;
+
+ if (alu32) {
+ src_known = tnum_subreg_is_const(src_reg.var_off);
+ if ((src_known &&
+ (s32_min_val != s32_max_val || u32_min_val != u32_max_val)) ||
+ s32_min_val > s32_max_val || u32_min_val > u32_max_val) {
+ /* Taint dst register if offset had invalid bounds
+ * derived from e.g. dead branches.
+ */
+ __mark_reg_unknown(env, dst_reg);
+ return 0;
+ }
+ } else {
+ src_known = tnum_is_const(src_reg.var_off);
+ if ((src_known &&
+ (smin_val != smax_val || umin_val != umax_val)) ||
+ smin_val > smax_val || umin_val > umax_val) {
+ /* Taint dst register if offset had invalid bounds
+ * derived from e.g. dead branches.
+ */
+ __mark_reg_unknown(env, dst_reg);
+ return 0;
+ }
+ }
+
+ if (!src_known &&
+ opcode != BPF_ADD && opcode != BPF_SUB && opcode != BPF_AND) {
+ __mark_reg_unknown(env, dst_reg);
+ return 0;
+ }
+
+ if (sanitize_needed(opcode)) {
+ ret = sanitize_val_alu(env, insn);
+ if (ret < 0)
+ return sanitize_err(env, insn, ret, NULL, NULL);
+ }
+
+ /* Calculate sign/unsigned bounds and tnum for alu32 and alu64 bit ops.
+ * There are two classes of instructions: The first class we track both
+ * alu32 and alu64 sign/unsigned bounds independently this provides the
+ * greatest amount of precision when alu operations are mixed with jmp32
+ * operations. These operations are BPF_ADD, BPF_SUB, BPF_MUL, BPF_ADD,
+ * and BPF_OR. This is possible because these ops have fairly easy to
+ * understand and calculate behavior in both 32-bit and 64-bit alu ops.
+ * See alu32 verifier tests for examples. The second class of
+ * operations, BPF_LSH, BPF_RSH, and BPF_ARSH, however are not so easy
+ * with regards to tracking sign/unsigned bounds because the bits may
+ * cross subreg boundaries in the alu64 case. When this happens we mark
+ * the reg unbounded in the subreg bound space and use the resulting
+ * tnum to calculate an approximation of the sign/unsigned bounds.
+ */
+ switch (opcode) {
+ case BPF_ADD:
+ scalar32_min_max_add(dst_reg, &src_reg);
+ scalar_min_max_add(dst_reg, &src_reg);
+ dst_reg->var_off = tnum_add(dst_reg->var_off, src_reg.var_off);
+ break;
+ case BPF_SUB:
+ scalar32_min_max_sub(dst_reg, &src_reg);
+ scalar_min_max_sub(dst_reg, &src_reg);
+ dst_reg->var_off = tnum_sub(dst_reg->var_off, src_reg.var_off);
+ break;
+ case BPF_MUL:
+ dst_reg->var_off = tnum_mul(dst_reg->var_off, src_reg.var_off);
+ scalar32_min_max_mul(dst_reg, &src_reg);
+ scalar_min_max_mul(dst_reg, &src_reg);
+ break;
+ case BPF_AND:
+ dst_reg->var_off = tnum_and(dst_reg->var_off, src_reg.var_off);
+ scalar32_min_max_and(dst_reg, &src_reg);
+ scalar_min_max_and(dst_reg, &src_reg);
+ break;
+ case BPF_OR:
+ dst_reg->var_off = tnum_or(dst_reg->var_off, src_reg.var_off);
+ scalar32_min_max_or(dst_reg, &src_reg);
+ scalar_min_max_or(dst_reg, &src_reg);
+ break;
+ case BPF_XOR:
+ dst_reg->var_off = tnum_xor(dst_reg->var_off, src_reg.var_off);
+ scalar32_min_max_xor(dst_reg, &src_reg);
+ scalar_min_max_xor(dst_reg, &src_reg);
+ break;
+ case BPF_LSH:
+ if (umax_val >= insn_bitness) {
+ /* Shifts greater than 31 or 63 are undefined.
+ * This includes shifts by a negative number.
+ */
+ mark_reg_unknown(env, regs, insn->dst_reg);
+ break;
+ }
+ if (alu32)
+ scalar32_min_max_lsh(dst_reg, &src_reg);
+ else
+ scalar_min_max_lsh(dst_reg, &src_reg);
+ break;
+ case BPF_RSH:
+ if (umax_val >= insn_bitness) {
+ /* Shifts greater than 31 or 63 are undefined.
+ * This includes shifts by a negative number.
+ */
+ mark_reg_unknown(env, regs, insn->dst_reg);
+ break;
+ }
+ if (alu32)
+ scalar32_min_max_rsh(dst_reg, &src_reg);
+ else
+ scalar_min_max_rsh(dst_reg, &src_reg);
+ break;
+ case BPF_ARSH:
+ if (umax_val >= insn_bitness) {
+ /* Shifts greater than 31 or 63 are undefined.
+ * This includes shifts by a negative number.
+ */
+ mark_reg_unknown(env, regs, insn->dst_reg);
+ break;
+ }
+ if (alu32)
+ scalar32_min_max_arsh(dst_reg, &src_reg);
+ else
+ scalar_min_max_arsh(dst_reg, &src_reg);
+ break;
+ default:
+ mark_reg_unknown(env, regs, insn->dst_reg);
+ break;
+ }
+
+ /* ALU32 ops are zero extended into 64bit register */
+ if (alu32)
+ zext_32_to_64(dst_reg);
+ reg_bounds_sync(dst_reg);
+ return 0;
+}
+
+/* Handles ALU ops other than BPF_END, BPF_NEG and BPF_MOV: computes new min/max
+ * and var_off.
+ */
+static int adjust_reg_min_max_vals(struct bpf_verifier_env *env,
+ struct bpf_insn *insn)
+{
+ struct bpf_verifier_state *vstate = env->cur_state;
+ struct bpf_func_state *state = vstate->frame[vstate->curframe];
+ struct bpf_reg_state *regs = state->regs, *dst_reg, *src_reg;
+ struct bpf_reg_state *ptr_reg = NULL, off_reg = {0};
+ u8 opcode = BPF_OP(insn->code);
+ int err;
+
+ dst_reg = &regs[insn->dst_reg];
+ src_reg = NULL;
+ if (dst_reg->type != SCALAR_VALUE)
+ ptr_reg = dst_reg;
+ else
+ /* Make sure ID is cleared otherwise dst_reg min/max could be
+ * incorrectly propagated into other registers by find_equal_scalars()
+ */
+ dst_reg->id = 0;
+ if (BPF_SRC(insn->code) == BPF_X) {
+ src_reg = &regs[insn->src_reg];
+ if (src_reg->type != SCALAR_VALUE) {
+ if (dst_reg->type != SCALAR_VALUE) {
+ /* Combining two pointers by any ALU op yields
+ * an arbitrary scalar. Disallow all math except
+ * pointer subtraction
+ */
+ if (opcode == BPF_SUB && env->allow_ptr_leaks) {
+ mark_reg_unknown(env, regs, insn->dst_reg);
+ return 0;
+ }
+ verbose(env, "R%d pointer %s pointer prohibited\n",
+ insn->dst_reg,
+ bpf_alu_string[opcode >> 4]);
+ return -EACCES;
+ } else {
+ /* scalar += pointer
+ * This is legal, but we have to reverse our
+ * src/dest handling in computing the range
+ */
+ err = mark_chain_precision(env, insn->dst_reg);
+ if (err)
+ return err;
+ return adjust_ptr_min_max_vals(env, insn,
+ src_reg, dst_reg);
+ }
+ } else if (ptr_reg) {
+ /* pointer += scalar */
+ err = mark_chain_precision(env, insn->src_reg);
+ if (err)
+ return err;
+ return adjust_ptr_min_max_vals(env, insn,
+ dst_reg, src_reg);
+ } else if (dst_reg->precise) {
+ /* if dst_reg is precise, src_reg should be precise as well */
+ err = mark_chain_precision(env, insn->src_reg);
+ if (err)
+ return err;
+ }
+ } else {
+ /* Pretend the src is a reg with a known value, since we only
+ * need to be able to read from this state.
+ */
+ off_reg.type = SCALAR_VALUE;
+ __mark_reg_known(&off_reg, insn->imm);
+ src_reg = &off_reg;
+ if (ptr_reg) /* pointer += K */
+ return adjust_ptr_min_max_vals(env, insn,
+ ptr_reg, src_reg);
+ }
+
+ /* Got here implies adding two SCALAR_VALUEs */
+ if (WARN_ON_ONCE(ptr_reg)) {
+ print_verifier_state(env, state, true);
+ verbose(env, "verifier internal error: unexpected ptr_reg\n");
+ return -EINVAL;
+ }
+ if (WARN_ON(!src_reg)) {
+ print_verifier_state(env, state, true);
+ verbose(env, "verifier internal error: no src_reg\n");
+ return -EINVAL;
+ }
+ return adjust_scalar_min_max_vals(env, insn, dst_reg, *src_reg);
+}
+
+/* check validity of 32-bit and 64-bit arithmetic operations */
+static int check_alu_op(struct bpf_verifier_env *env, struct bpf_insn *insn)
+{
+ struct bpf_reg_state *regs = cur_regs(env);
+ u8 opcode = BPF_OP(insn->code);
+ int err;
+
+ if (opcode == BPF_END || opcode == BPF_NEG) {
+ if (opcode == BPF_NEG) {
+ if (BPF_SRC(insn->code) != BPF_K ||
+ insn->src_reg != BPF_REG_0 ||
+ insn->off != 0 || insn->imm != 0) {
+ verbose(env, "BPF_NEG uses reserved fields\n");
+ return -EINVAL;
+ }
+ } else {
+ if (insn->src_reg != BPF_REG_0 || insn->off != 0 ||
+ (insn->imm != 16 && insn->imm != 32 && insn->imm != 64) ||
+ (BPF_CLASS(insn->code) == BPF_ALU64 &&
+ BPF_SRC(insn->code) != BPF_TO_LE)) {
+ verbose(env, "BPF_END uses reserved fields\n");
+ return -EINVAL;
+ }
+ }
+
+ /* check src operand */
+ err = check_reg_arg(env, insn->dst_reg, SRC_OP);
+ if (err)
+ return err;
+
+ if (is_pointer_value(env, insn->dst_reg)) {
+ verbose(env, "R%d pointer arithmetic prohibited\n",
+ insn->dst_reg);
+ return -EACCES;
+ }
+
+ /* check dest operand */
+ err = check_reg_arg(env, insn->dst_reg, DST_OP);
+ if (err)
+ return err;
+
+ } else if (opcode == BPF_MOV) {
+
+ if (BPF_SRC(insn->code) == BPF_X) {
+ if (insn->imm != 0) {
+ verbose(env, "BPF_MOV uses reserved fields\n");
+ return -EINVAL;
+ }
+
+ if (BPF_CLASS(insn->code) == BPF_ALU) {
+ if (insn->off != 0 && insn->off != 8 && insn->off != 16) {
+ verbose(env, "BPF_MOV uses reserved fields\n");
+ return -EINVAL;
+ }
+ } else {
+ if (insn->off != 0 && insn->off != 8 && insn->off != 16 &&
+ insn->off != 32) {
+ verbose(env, "BPF_MOV uses reserved fields\n");
+ return -EINVAL;
+ }
+ }
+
+ /* check src operand */
+ err = check_reg_arg(env, insn->src_reg, SRC_OP);
+ if (err)
+ return err;
+ } else {
+ if (insn->src_reg != BPF_REG_0 || insn->off != 0) {
+ verbose(env, "BPF_MOV uses reserved fields\n");
+ return -EINVAL;
+ }
+ }
+
+ /* check dest operand, mark as required later */
+ err = check_reg_arg(env, insn->dst_reg, DST_OP_NO_MARK);
+ if (err)
+ return err;
+
+ if (BPF_SRC(insn->code) == BPF_X) {
+ struct bpf_reg_state *src_reg = regs + insn->src_reg;
+ struct bpf_reg_state *dst_reg = regs + insn->dst_reg;
+ bool need_id = src_reg->type == SCALAR_VALUE && !src_reg->id &&
+ !tnum_is_const(src_reg->var_off);
+
+ if (BPF_CLASS(insn->code) == BPF_ALU64) {
+ if (insn->off == 0) {
+ /* case: R1 = R2
+ * copy register state to dest reg
+ */
+ if (need_id)
+ /* Assign src and dst registers the same ID
+ * that will be used by find_equal_scalars()
+ * to propagate min/max range.
+ */
+ src_reg->id = ++env->id_gen;
+ copy_register_state(dst_reg, src_reg);
+ dst_reg->live |= REG_LIVE_WRITTEN;
+ dst_reg->subreg_def = DEF_NOT_SUBREG;
+ } else {
+ /* case: R1 = (s8, s16 s32)R2 */
+ if (is_pointer_value(env, insn->src_reg)) {
+ verbose(env,
+ "R%d sign-extension part of pointer\n",
+ insn->src_reg);
+ return -EACCES;
+ } else if (src_reg->type == SCALAR_VALUE) {
+ bool no_sext;
+
+ no_sext = src_reg->umax_value < (1ULL << (insn->off - 1));
+ if (no_sext && need_id)
+ src_reg->id = ++env->id_gen;
+ copy_register_state(dst_reg, src_reg);
+ if (!no_sext)
+ dst_reg->id = 0;
+ coerce_reg_to_size_sx(dst_reg, insn->off >> 3);
+ dst_reg->live |= REG_LIVE_WRITTEN;
+ dst_reg->subreg_def = DEF_NOT_SUBREG;
+ } else {
+ mark_reg_unknown(env, regs, insn->dst_reg);
+ }
+ }
+ } else {
+ /* R1 = (u32) R2 */
+ if (is_pointer_value(env, insn->src_reg)) {
+ verbose(env,
+ "R%d partial copy of pointer\n",
+ insn->src_reg);
+ return -EACCES;
+ } else if (src_reg->type == SCALAR_VALUE) {
+ if (insn->off == 0) {
+ bool is_src_reg_u32 = src_reg->umax_value <= U32_MAX;
+
+ if (is_src_reg_u32 && need_id)
+ src_reg->id = ++env->id_gen;
+ copy_register_state(dst_reg, src_reg);
+ /* Make sure ID is cleared if src_reg is not in u32
+ * range otherwise dst_reg min/max could be incorrectly
+ * propagated into src_reg by find_equal_scalars()
+ */
+ if (!is_src_reg_u32)
+ dst_reg->id = 0;
+ dst_reg->live |= REG_LIVE_WRITTEN;
+ dst_reg->subreg_def = env->insn_idx + 1;
+ } else {
+ /* case: W1 = (s8, s16)W2 */
+ bool no_sext = src_reg->umax_value < (1ULL << (insn->off - 1));
+
+ if (no_sext && need_id)
+ src_reg->id = ++env->id_gen;
+ copy_register_state(dst_reg, src_reg);
+ if (!no_sext)
+ dst_reg->id = 0;
+ dst_reg->live |= REG_LIVE_WRITTEN;
+ dst_reg->subreg_def = env->insn_idx + 1;
+ coerce_subreg_to_size_sx(dst_reg, insn->off >> 3);
+ }
+ } else {
+ mark_reg_unknown(env, regs,
+ insn->dst_reg);
+ }
+ zext_32_to_64(dst_reg);
+ reg_bounds_sync(dst_reg);
+ }
+ } else {
+ /* case: R = imm
+ * remember the value we stored into this reg
+ */
+ /* clear any state __mark_reg_known doesn't set */
+ mark_reg_unknown(env, regs, insn->dst_reg);
+ regs[insn->dst_reg].type = SCALAR_VALUE;
+ if (BPF_CLASS(insn->code) == BPF_ALU64) {
+ __mark_reg_known(regs + insn->dst_reg,
+ insn->imm);
+ } else {
+ __mark_reg_known(regs + insn->dst_reg,
+ (u32)insn->imm);
+ }
+ }
+
+ } else if (opcode > BPF_END) {
+ verbose(env, "invalid BPF_ALU opcode %x\n", opcode);
+ return -EINVAL;
+
+ } else { /* all other ALU ops: and, sub, xor, add, ... */
+
+ if (BPF_SRC(insn->code) == BPF_X) {
+ if (insn->imm != 0 || insn->off > 1 ||
+ (insn->off == 1 && opcode != BPF_MOD && opcode != BPF_DIV)) {
+ verbose(env, "BPF_ALU uses reserved fields\n");
+ return -EINVAL;
+ }
+ /* check src1 operand */
+ err = check_reg_arg(env, insn->src_reg, SRC_OP);
+ if (err)
+ return err;
+ } else {
+ if (insn->src_reg != BPF_REG_0 || insn->off > 1 ||
+ (insn->off == 1 && opcode != BPF_MOD && opcode != BPF_DIV)) {
+ verbose(env, "BPF_ALU uses reserved fields\n");
+ return -EINVAL;
+ }
+ }
+
+ /* check src2 operand */
+ err = check_reg_arg(env, insn->dst_reg, SRC_OP);
+ if (err)
+ return err;
+
+ if ((opcode == BPF_MOD || opcode == BPF_DIV) &&
+ BPF_SRC(insn->code) == BPF_K && insn->imm == 0) {
+ verbose(env, "div by zero\n");
+ return -EINVAL;
+ }
+
+ if ((opcode == BPF_LSH || opcode == BPF_RSH ||
+ opcode == BPF_ARSH) && BPF_SRC(insn->code) == BPF_K) {
+ int size = BPF_CLASS(insn->code) == BPF_ALU64 ? 64 : 32;
+
+ if (insn->imm < 0 || insn->imm >= size) {
+ verbose(env, "invalid shift %d\n", insn->imm);
+ return -EINVAL;
+ }
+ }
+
+ /* check dest operand */
+ err = check_reg_arg(env, insn->dst_reg, DST_OP_NO_MARK);
+ if (err)
+ return err;
+
+ return adjust_reg_min_max_vals(env, insn);
+ }
+
+ return 0;
+}
+
+static void find_good_pkt_pointers(struct bpf_verifier_state *vstate,
+ struct bpf_reg_state *dst_reg,
+ enum bpf_reg_type type,
+ bool range_right_open)
+{
+ struct bpf_func_state *state;
+ struct bpf_reg_state *reg;
+ int new_range;
+
+ if (dst_reg->off < 0 ||
+ (dst_reg->off == 0 && range_right_open))
+ /* This doesn't give us any range */
+ return;
+
+ if (dst_reg->umax_value > MAX_PACKET_OFF ||
+ dst_reg->umax_value + dst_reg->off > MAX_PACKET_OFF)
+ /* Risk of overflow. For instance, ptr + (1<<63) may be less
+ * than pkt_end, but that's because it's also less than pkt.
+ */
+ return;
+
+ new_range = dst_reg->off;
+ if (range_right_open)
+ new_range++;
+
+ /* Examples for register markings:
+ *
+ * pkt_data in dst register:
+ *
+ * r2 = r3;
+ * r2 += 8;
+ * if (r2 > pkt_end) goto <handle exception>
+ * <access okay>
+ *
+ * r2 = r3;
+ * r2 += 8;
+ * if (r2 < pkt_end) goto <access okay>
+ * <handle exception>
+ *
+ * Where:
+ * r2 == dst_reg, pkt_end == src_reg
+ * r2=pkt(id=n,off=8,r=0)
+ * r3=pkt(id=n,off=0,r=0)
+ *
+ * pkt_data in src register:
+ *
+ * r2 = r3;
+ * r2 += 8;
+ * if (pkt_end >= r2) goto <access okay>
+ * <handle exception>
+ *
+ * r2 = r3;
+ * r2 += 8;
+ * if (pkt_end <= r2) goto <handle exception>
+ * <access okay>
+ *
+ * Where:
+ * pkt_end == dst_reg, r2 == src_reg
+ * r2=pkt(id=n,off=8,r=0)
+ * r3=pkt(id=n,off=0,r=0)
+ *
+ * Find register r3 and mark its range as r3=pkt(id=n,off=0,r=8)
+ * or r3=pkt(id=n,off=0,r=8-1), so that range of bytes [r3, r3 + 8)
+ * and [r3, r3 + 8-1) respectively is safe to access depending on
+ * the check.
+ */
+
+ /* If our ids match, then we must have the same max_value. And we
+ * don't care about the other reg's fixed offset, since if it's too big
+ * the range won't allow anything.
+ * dst_reg->off is known < MAX_PACKET_OFF, therefore it fits in a u16.
+ */
+ bpf_for_each_reg_in_vstate(vstate, state, reg, ({
+ if (reg->type == type && reg->id == dst_reg->id)
+ /* keep the maximum range already checked */
+ reg->range = max(reg->range, new_range);
+ }));
+}
+
+static int is_branch32_taken(struct bpf_reg_state *reg, u32 val, u8 opcode)
+{
+ struct tnum subreg = tnum_subreg(reg->var_off);
+ s32 sval = (s32)val;
+
+ switch (opcode) {
+ case BPF_JEQ:
+ if (tnum_is_const(subreg))
+ return !!tnum_equals_const(subreg, val);
+ else if (val < reg->u32_min_value || val > reg->u32_max_value)
+ return 0;
+ break;
+ case BPF_JNE:
+ if (tnum_is_const(subreg))
+ return !tnum_equals_const(subreg, val);
+ else if (val < reg->u32_min_value || val > reg->u32_max_value)
+ return 1;
+ break;
+ case BPF_JSET:
+ if ((~subreg.mask & subreg.value) & val)
+ return 1;
+ if (!((subreg.mask | subreg.value) & val))
+ return 0;
+ break;
+ case BPF_JGT:
+ if (reg->u32_min_value > val)
+ return 1;
+ else if (reg->u32_max_value <= val)
+ return 0;
+ break;
+ case BPF_JSGT:
+ if (reg->s32_min_value > sval)
+ return 1;
+ else if (reg->s32_max_value <= sval)
+ return 0;
+ break;
+ case BPF_JLT:
+ if (reg->u32_max_value < val)
+ return 1;
+ else if (reg->u32_min_value >= val)
+ return 0;
+ break;
+ case BPF_JSLT:
+ if (reg->s32_max_value < sval)
+ return 1;
+ else if (reg->s32_min_value >= sval)
+ return 0;
+ break;
+ case BPF_JGE:
+ if (reg->u32_min_value >= val)
+ return 1;
+ else if (reg->u32_max_value < val)
+ return 0;
+ break;
+ case BPF_JSGE:
+ if (reg->s32_min_value >= sval)
+ return 1;
+ else if (reg->s32_max_value < sval)
+ return 0;
+ break;
+ case BPF_JLE:
+ if (reg->u32_max_value <= val)
+ return 1;
+ else if (reg->u32_min_value > val)
+ return 0;
+ break;
+ case BPF_JSLE:
+ if (reg->s32_max_value <= sval)
+ return 1;
+ else if (reg->s32_min_value > sval)
+ return 0;
+ break;
+ }
+
+ return -1;
+}
+
+
+static int is_branch64_taken(struct bpf_reg_state *reg, u64 val, u8 opcode)
+{
+ s64 sval = (s64)val;
+
+ switch (opcode) {
+ case BPF_JEQ:
+ if (tnum_is_const(reg->var_off))
+ return !!tnum_equals_const(reg->var_off, val);
+ else if (val < reg->umin_value || val > reg->umax_value)
+ return 0;
+ break;
+ case BPF_JNE:
+ if (tnum_is_const(reg->var_off))
+ return !tnum_equals_const(reg->var_off, val);
+ else if (val < reg->umin_value || val > reg->umax_value)
+ return 1;
+ break;
+ case BPF_JSET:
+ if ((~reg->var_off.mask & reg->var_off.value) & val)
+ return 1;
+ if (!((reg->var_off.mask | reg->var_off.value) & val))
+ return 0;
+ break;
+ case BPF_JGT:
+ if (reg->umin_value > val)
+ return 1;
+ else if (reg->umax_value <= val)
+ return 0;
+ break;
+ case BPF_JSGT:
+ if (reg->smin_value > sval)
+ return 1;
+ else if (reg->smax_value <= sval)
+ return 0;
+ break;
+ case BPF_JLT:
+ if (reg->umax_value < val)
+ return 1;
+ else if (reg->umin_value >= val)
+ return 0;
+ break;
+ case BPF_JSLT:
+ if (reg->smax_value < sval)
+ return 1;
+ else if (reg->smin_value >= sval)
+ return 0;
+ break;
+ case BPF_JGE:
+ if (reg->umin_value >= val)
+ return 1;
+ else if (reg->umax_value < val)
+ return 0;
+ break;
+ case BPF_JSGE:
+ if (reg->smin_value >= sval)
+ return 1;
+ else if (reg->smax_value < sval)
+ return 0;
+ break;
+ case BPF_JLE:
+ if (reg->umax_value <= val)
+ return 1;
+ else if (reg->umin_value > val)
+ return 0;
+ break;
+ case BPF_JSLE:
+ if (reg->smax_value <= sval)
+ return 1;
+ else if (reg->smin_value > sval)
+ return 0;
+ break;
+ }
+
+ return -1;
+}
+
+/* compute branch direction of the expression "if (reg opcode val) goto target;"
+ * and return:
+ * 1 - branch will be taken and "goto target" will be executed
+ * 0 - branch will not be taken and fall-through to next insn
+ * -1 - unknown. Example: "if (reg < 5)" is unknown when register value
+ * range [0,10]
+ */
+static int is_branch_taken(struct bpf_reg_state *reg, u64 val, u8 opcode,
+ bool is_jmp32)
+{
+ if (__is_pointer_value(false, reg)) {
+ if (!reg_not_null(reg))
+ return -1;
+
+ /* If pointer is valid tests against zero will fail so we can
+ * use this to direct branch taken.
+ */
+ if (val != 0)
+ return -1;
+
+ switch (opcode) {
+ case BPF_JEQ:
+ return 0;
+ case BPF_JNE:
+ return 1;
+ default:
+ return -1;
+ }
+ }
+
+ if (is_jmp32)
+ return is_branch32_taken(reg, val, opcode);
+ return is_branch64_taken(reg, val, opcode);
+}
+
+static int flip_opcode(u32 opcode)
+{
+ /* How can we transform "a <op> b" into "b <op> a"? */
+ static const u8 opcode_flip[16] = {
+ /* these stay the same */
+ [BPF_JEQ >> 4] = BPF_JEQ,
+ [BPF_JNE >> 4] = BPF_JNE,
+ [BPF_JSET >> 4] = BPF_JSET,
+ /* these swap "lesser" and "greater" (L and G in the opcodes) */
+ [BPF_JGE >> 4] = BPF_JLE,
+ [BPF_JGT >> 4] = BPF_JLT,
+ [BPF_JLE >> 4] = BPF_JGE,
+ [BPF_JLT >> 4] = BPF_JGT,
+ [BPF_JSGE >> 4] = BPF_JSLE,
+ [BPF_JSGT >> 4] = BPF_JSLT,
+ [BPF_JSLE >> 4] = BPF_JSGE,
+ [BPF_JSLT >> 4] = BPF_JSGT
+ };
+ return opcode_flip[opcode >> 4];
+}
+
+static int is_pkt_ptr_branch_taken(struct bpf_reg_state *dst_reg,
+ struct bpf_reg_state *src_reg,
+ u8 opcode)
+{
+ struct bpf_reg_state *pkt;
+
+ if (src_reg->type == PTR_TO_PACKET_END) {
+ pkt = dst_reg;
+ } else if (dst_reg->type == PTR_TO_PACKET_END) {
+ pkt = src_reg;
+ opcode = flip_opcode(opcode);
+ } else {
+ return -1;
+ }
+
+ if (pkt->range >= 0)
+ return -1;
+
+ switch (opcode) {
+ case BPF_JLE:
+ /* pkt <= pkt_end */
+ fallthrough;
+ case BPF_JGT:
+ /* pkt > pkt_end */
+ if (pkt->range == BEYOND_PKT_END)
+ /* pkt has at last one extra byte beyond pkt_end */
+ return opcode == BPF_JGT;
+ break;
+ case BPF_JLT:
+ /* pkt < pkt_end */
+ fallthrough;
+ case BPF_JGE:
+ /* pkt >= pkt_end */
+ if (pkt->range == BEYOND_PKT_END || pkt->range == AT_PKT_END)
+ return opcode == BPF_JGE;
+ break;
+ }
+ return -1;
+}
+
+/* Adjusts the register min/max values in the case that the dst_reg is the
+ * variable register that we are working on, and src_reg is a constant or we're
+ * simply doing a BPF_K check.
+ * In JEQ/JNE cases we also adjust the var_off values.
+ */
+static void reg_set_min_max(struct bpf_reg_state *true_reg,
+ struct bpf_reg_state *false_reg,
+ u64 val, u32 val32,
+ u8 opcode, bool is_jmp32)
+{
+ struct tnum false_32off = tnum_subreg(false_reg->var_off);
+ struct tnum false_64off = false_reg->var_off;
+ struct tnum true_32off = tnum_subreg(true_reg->var_off);
+ struct tnum true_64off = true_reg->var_off;
+ s64 sval = (s64)val;
+ s32 sval32 = (s32)val32;
+
+ /* If the dst_reg is a pointer, we can't learn anything about its
+ * variable offset from the compare (unless src_reg were a pointer into
+ * the same object, but we don't bother with that.
+ * Since false_reg and true_reg have the same type by construction, we
+ * only need to check one of them for pointerness.
+ */
+ if (__is_pointer_value(false, false_reg))
+ return;
+
+ switch (opcode) {
+ /* JEQ/JNE comparison doesn't change the register equivalence.
+ *
+ * r1 = r2;
+ * if (r1 == 42) goto label;
+ * ...
+ * label: // here both r1 and r2 are known to be 42.
+ *
+ * Hence when marking register as known preserve it's ID.
+ */
+ case BPF_JEQ:
+ if (is_jmp32) {
+ __mark_reg32_known(true_reg, val32);
+ true_32off = tnum_subreg(true_reg->var_off);
+ } else {
+ ___mark_reg_known(true_reg, val);
+ true_64off = true_reg->var_off;
+ }
+ break;
+ case BPF_JNE:
+ if (is_jmp32) {
+ __mark_reg32_known(false_reg, val32);
+ false_32off = tnum_subreg(false_reg->var_off);
+ } else {
+ ___mark_reg_known(false_reg, val);
+ false_64off = false_reg->var_off;
+ }
+ break;
+ case BPF_JSET:
+ if (is_jmp32) {
+ false_32off = tnum_and(false_32off, tnum_const(~val32));
+ if (is_power_of_2(val32))
+ true_32off = tnum_or(true_32off,
+ tnum_const(val32));
+ } else {
+ false_64off = tnum_and(false_64off, tnum_const(~val));
+ if (is_power_of_2(val))
+ true_64off = tnum_or(true_64off,
+ tnum_const(val));
+ }
+ break;
+ case BPF_JGE:
+ case BPF_JGT:
+ {
+ if (is_jmp32) {
+ u32 false_umax = opcode == BPF_JGT ? val32 : val32 - 1;
+ u32 true_umin = opcode == BPF_JGT ? val32 + 1 : val32;
+
+ false_reg->u32_max_value = min(false_reg->u32_max_value,
+ false_umax);
+ true_reg->u32_min_value = max(true_reg->u32_min_value,
+ true_umin);
+ } else {
+ u64 false_umax = opcode == BPF_JGT ? val : val - 1;
+ u64 true_umin = opcode == BPF_JGT ? val + 1 : val;
+
+ false_reg->umax_value = min(false_reg->umax_value, false_umax);
+ true_reg->umin_value = max(true_reg->umin_value, true_umin);
+ }
+ break;
+ }
+ case BPF_JSGE:
+ case BPF_JSGT:
+ {
+ if (is_jmp32) {
+ s32 false_smax = opcode == BPF_JSGT ? sval32 : sval32 - 1;
+ s32 true_smin = opcode == BPF_JSGT ? sval32 + 1 : sval32;
+
+ false_reg->s32_max_value = min(false_reg->s32_max_value, false_smax);
+ true_reg->s32_min_value = max(true_reg->s32_min_value, true_smin);
+ } else {
+ s64 false_smax = opcode == BPF_JSGT ? sval : sval - 1;
+ s64 true_smin = opcode == BPF_JSGT ? sval + 1 : sval;
+
+ false_reg->smax_value = min(false_reg->smax_value, false_smax);
+ true_reg->smin_value = max(true_reg->smin_value, true_smin);
+ }
+ break;
+ }
+ case BPF_JLE:
+ case BPF_JLT:
+ {
+ if (is_jmp32) {
+ u32 false_umin = opcode == BPF_JLT ? val32 : val32 + 1;
+ u32 true_umax = opcode == BPF_JLT ? val32 - 1 : val32;
+
+ false_reg->u32_min_value = max(false_reg->u32_min_value,
+ false_umin);
+ true_reg->u32_max_value = min(true_reg->u32_max_value,
+ true_umax);
+ } else {
+ u64 false_umin = opcode == BPF_JLT ? val : val + 1;
+ u64 true_umax = opcode == BPF_JLT ? val - 1 : val;
+
+ false_reg->umin_value = max(false_reg->umin_value, false_umin);
+ true_reg->umax_value = min(true_reg->umax_value, true_umax);
+ }
+ break;
+ }
+ case BPF_JSLE:
+ case BPF_JSLT:
+ {
+ if (is_jmp32) {
+ s32 false_smin = opcode == BPF_JSLT ? sval32 : sval32 + 1;
+ s32 true_smax = opcode == BPF_JSLT ? sval32 - 1 : sval32;
+
+ false_reg->s32_min_value = max(false_reg->s32_min_value, false_smin);
+ true_reg->s32_max_value = min(true_reg->s32_max_value, true_smax);
+ } else {
+ s64 false_smin = opcode == BPF_JSLT ? sval : sval + 1;
+ s64 true_smax = opcode == BPF_JSLT ? sval - 1 : sval;
+
+ false_reg->smin_value = max(false_reg->smin_value, false_smin);
+ true_reg->smax_value = min(true_reg->smax_value, true_smax);
+ }
+ break;
+ }
+ default:
+ return;
+ }
+
+ if (is_jmp32) {
+ false_reg->var_off = tnum_or(tnum_clear_subreg(false_64off),
+ tnum_subreg(false_32off));
+ true_reg->var_off = tnum_or(tnum_clear_subreg(true_64off),
+ tnum_subreg(true_32off));
+ __reg_combine_32_into_64(false_reg);
+ __reg_combine_32_into_64(true_reg);
+ } else {
+ false_reg->var_off = false_64off;
+ true_reg->var_off = true_64off;
+ __reg_combine_64_into_32(false_reg);
+ __reg_combine_64_into_32(true_reg);
+ }
+}
+
+/* Same as above, but for the case that dst_reg holds a constant and src_reg is
+ * the variable reg.
+ */
+static void reg_set_min_max_inv(struct bpf_reg_state *true_reg,
+ struct bpf_reg_state *false_reg,
+ u64 val, u32 val32,
+ u8 opcode, bool is_jmp32)
+{
+ opcode = flip_opcode(opcode);
+ /* This uses zero as "not present in table"; luckily the zero opcode,
+ * BPF_JA, can't get here.
+ */
+ if (opcode)
+ reg_set_min_max(true_reg, false_reg, val, val32, opcode, is_jmp32);
+}
+
+/* Regs are known to be equal, so intersect their min/max/var_off */
+static void __reg_combine_min_max(struct bpf_reg_state *src_reg,
+ struct bpf_reg_state *dst_reg)
+{
+ src_reg->umin_value = dst_reg->umin_value = max(src_reg->umin_value,
+ dst_reg->umin_value);
+ src_reg->umax_value = dst_reg->umax_value = min(src_reg->umax_value,
+ dst_reg->umax_value);
+ src_reg->smin_value = dst_reg->smin_value = max(src_reg->smin_value,
+ dst_reg->smin_value);
+ src_reg->smax_value = dst_reg->smax_value = min(src_reg->smax_value,
+ dst_reg->smax_value);
+ src_reg->var_off = dst_reg->var_off = tnum_intersect(src_reg->var_off,
+ dst_reg->var_off);
+ reg_bounds_sync(src_reg);
+ reg_bounds_sync(dst_reg);
+}
+
+static void reg_combine_min_max(struct bpf_reg_state *true_src,
+ struct bpf_reg_state *true_dst,
+ struct bpf_reg_state *false_src,
+ struct bpf_reg_state *false_dst,
+ u8 opcode)
+{
+ switch (opcode) {
+ case BPF_JEQ:
+ __reg_combine_min_max(true_src, true_dst);
+ break;
+ case BPF_JNE:
+ __reg_combine_min_max(false_src, false_dst);
+ break;
+ }
+}
+
+static void mark_ptr_or_null_reg(struct bpf_func_state *state,
+ struct bpf_reg_state *reg, u32 id,
+ bool is_null)
+{
+ if (type_may_be_null(reg->type) && reg->id == id &&
+ (is_rcu_reg(reg) || !WARN_ON_ONCE(!reg->id))) {
+ /* Old offset (both fixed and variable parts) should have been
+ * known-zero, because we don't allow pointer arithmetic on
+ * pointers that might be NULL. If we see this happening, don't
+ * convert the register.
+ *
+ * But in some cases, some helpers that return local kptrs
+ * advance offset for the returned pointer. In those cases, it
+ * is fine to expect to see reg->off.
+ */
+ if (WARN_ON_ONCE(reg->smin_value || reg->smax_value || !tnum_equals_const(reg->var_off, 0)))
+ return;
+ if (!(type_is_ptr_alloc_obj(reg->type) || type_is_non_owning_ref(reg->type)) &&
+ WARN_ON_ONCE(reg->off))
+ return;
+
+ if (is_null) {
+ reg->type = SCALAR_VALUE;
+ /* We don't need id and ref_obj_id from this point
+ * onwards anymore, thus we should better reset it,
+ * so that state pruning has chances to take effect.
+ */
+ reg->id = 0;
+ reg->ref_obj_id = 0;
+
+ return;
+ }
+
+ mark_ptr_not_null_reg(reg);
+
+ if (!reg_may_point_to_spin_lock(reg)) {
+ /* For not-NULL ptr, reg->ref_obj_id will be reset
+ * in release_reference().
+ *
+ * reg->id is still used by spin_lock ptr. Other
+ * than spin_lock ptr type, reg->id can be reset.
+ */
+ reg->id = 0;
+ }
+ }
+}
+
+/* The logic is similar to find_good_pkt_pointers(), both could eventually
+ * be folded together at some point.
+ */
+static void mark_ptr_or_null_regs(struct bpf_verifier_state *vstate, u32 regno,
+ bool is_null)
+{
+ struct bpf_func_state *state = vstate->frame[vstate->curframe];
+ struct bpf_reg_state *regs = state->regs, *reg;
+ u32 ref_obj_id = regs[regno].ref_obj_id;
+ u32 id = regs[regno].id;
+
+ if (ref_obj_id && ref_obj_id == id && is_null)
+ /* regs[regno] is in the " == NULL" branch.
+ * No one could have freed the reference state before
+ * doing the NULL check.
+ */
+ WARN_ON_ONCE(release_reference_state(state, id));
+
+ bpf_for_each_reg_in_vstate(vstate, state, reg, ({
+ mark_ptr_or_null_reg(state, reg, id, is_null);
+ }));
+}
+
+static bool try_match_pkt_pointers(const struct bpf_insn *insn,
+ struct bpf_reg_state *dst_reg,
+ struct bpf_reg_state *src_reg,
+ struct bpf_verifier_state *this_branch,
+ struct bpf_verifier_state *other_branch)
+{
+ if (BPF_SRC(insn->code) != BPF_X)
+ return false;
+
+ /* Pointers are always 64-bit. */
+ if (BPF_CLASS(insn->code) == BPF_JMP32)
+ return false;
+
+ switch (BPF_OP(insn->code)) {
+ case BPF_JGT:
+ if ((dst_reg->type == PTR_TO_PACKET &&
+ src_reg->type == PTR_TO_PACKET_END) ||
+ (dst_reg->type == PTR_TO_PACKET_META &&
+ reg_is_init_pkt_pointer(src_reg, PTR_TO_PACKET))) {
+ /* pkt_data' > pkt_end, pkt_meta' > pkt_data */
+ find_good_pkt_pointers(this_branch, dst_reg,
+ dst_reg->type, false);
+ mark_pkt_end(other_branch, insn->dst_reg, true);
+ } else if ((dst_reg->type == PTR_TO_PACKET_END &&
+ src_reg->type == PTR_TO_PACKET) ||
+ (reg_is_init_pkt_pointer(dst_reg, PTR_TO_PACKET) &&
+ src_reg->type == PTR_TO_PACKET_META)) {
+ /* pkt_end > pkt_data', pkt_data > pkt_meta' */
+ find_good_pkt_pointers(other_branch, src_reg,
+ src_reg->type, true);
+ mark_pkt_end(this_branch, insn->src_reg, false);
+ } else {
+ return false;
+ }
+ break;
+ case BPF_JLT:
+ if ((dst_reg->type == PTR_TO_PACKET &&
+ src_reg->type == PTR_TO_PACKET_END) ||
+ (dst_reg->type == PTR_TO_PACKET_META &&
+ reg_is_init_pkt_pointer(src_reg, PTR_TO_PACKET))) {
+ /* pkt_data' < pkt_end, pkt_meta' < pkt_data */
+ find_good_pkt_pointers(other_branch, dst_reg,
+ dst_reg->type, true);
+ mark_pkt_end(this_branch, insn->dst_reg, false);
+ } else if ((dst_reg->type == PTR_TO_PACKET_END &&
+ src_reg->type == PTR_TO_PACKET) ||
+ (reg_is_init_pkt_pointer(dst_reg, PTR_TO_PACKET) &&
+ src_reg->type == PTR_TO_PACKET_META)) {
+ /* pkt_end < pkt_data', pkt_data > pkt_meta' */
+ find_good_pkt_pointers(this_branch, src_reg,
+ src_reg->type, false);
+ mark_pkt_end(other_branch, insn->src_reg, true);
+ } else {
+ return false;
+ }
+ break;
+ case BPF_JGE:
+ if ((dst_reg->type == PTR_TO_PACKET &&
+ src_reg->type == PTR_TO_PACKET_END) ||
+ (dst_reg->type == PTR_TO_PACKET_META &&
+ reg_is_init_pkt_pointer(src_reg, PTR_TO_PACKET))) {
+ /* pkt_data' >= pkt_end, pkt_meta' >= pkt_data */
+ find_good_pkt_pointers(this_branch, dst_reg,
+ dst_reg->type, true);
+ mark_pkt_end(other_branch, insn->dst_reg, false);
+ } else if ((dst_reg->type == PTR_TO_PACKET_END &&
+ src_reg->type == PTR_TO_PACKET) ||
+ (reg_is_init_pkt_pointer(dst_reg, PTR_TO_PACKET) &&
+ src_reg->type == PTR_TO_PACKET_META)) {
+ /* pkt_end >= pkt_data', pkt_data >= pkt_meta' */
+ find_good_pkt_pointers(other_branch, src_reg,
+ src_reg->type, false);
+ mark_pkt_end(this_branch, insn->src_reg, true);
+ } else {
+ return false;
+ }
+ break;
+ case BPF_JLE:
+ if ((dst_reg->type == PTR_TO_PACKET &&
+ src_reg->type == PTR_TO_PACKET_END) ||
+ (dst_reg->type == PTR_TO_PACKET_META &&
+ reg_is_init_pkt_pointer(src_reg, PTR_TO_PACKET))) {
+ /* pkt_data' <= pkt_end, pkt_meta' <= pkt_data */
+ find_good_pkt_pointers(other_branch, dst_reg,
+ dst_reg->type, false);
+ mark_pkt_end(this_branch, insn->dst_reg, true);
+ } else if ((dst_reg->type == PTR_TO_PACKET_END &&
+ src_reg->type == PTR_TO_PACKET) ||
+ (reg_is_init_pkt_pointer(dst_reg, PTR_TO_PACKET) &&
+ src_reg->type == PTR_TO_PACKET_META)) {
+ /* pkt_end <= pkt_data', pkt_data <= pkt_meta' */
+ find_good_pkt_pointers(this_branch, src_reg,
+ src_reg->type, true);
+ mark_pkt_end(other_branch, insn->src_reg, false);
+ } else {
+ return false;
+ }
+ break;
+ default:
+ return false;
+ }
+
+ return true;
+}
+
+static void find_equal_scalars(struct bpf_verifier_state *vstate,
+ struct bpf_reg_state *known_reg)
+{
+ struct bpf_func_state *state;
+ struct bpf_reg_state *reg;
+
+ bpf_for_each_reg_in_vstate(vstate, state, reg, ({
+ if (reg->type == SCALAR_VALUE && reg->id == known_reg->id)
+ copy_register_state(reg, known_reg);
+ }));
+}
+
+static int check_cond_jmp_op(struct bpf_verifier_env *env,
+ struct bpf_insn *insn, int *insn_idx)
+{
+ struct bpf_verifier_state *this_branch = env->cur_state;
+ struct bpf_verifier_state *other_branch;
+ struct bpf_reg_state *regs = this_branch->frame[this_branch->curframe]->regs;
+ struct bpf_reg_state *dst_reg, *other_branch_regs, *src_reg = NULL;
+ struct bpf_reg_state *eq_branch_regs;
+ u8 opcode = BPF_OP(insn->code);
+ bool is_jmp32;
+ int pred = -1;
+ int err;
+
+ /* Only conditional jumps are expected to reach here. */
+ if (opcode == BPF_JA || opcode > BPF_JSLE) {
+ verbose(env, "invalid BPF_JMP/JMP32 opcode %x\n", opcode);
+ return -EINVAL;
+ }
+
+ /* check src2 operand */
+ err = check_reg_arg(env, insn->dst_reg, SRC_OP);
+ if (err)
+ return err;
+
+ dst_reg = &regs[insn->dst_reg];
+ if (BPF_SRC(insn->code) == BPF_X) {
+ if (insn->imm != 0) {
+ verbose(env, "BPF_JMP/JMP32 uses reserved fields\n");
+ return -EINVAL;
+ }
+
+ /* check src1 operand */
+ err = check_reg_arg(env, insn->src_reg, SRC_OP);
+ if (err)
+ return err;
+
+ src_reg = &regs[insn->src_reg];
+ if (!(reg_is_pkt_pointer_any(dst_reg) && reg_is_pkt_pointer_any(src_reg)) &&
+ is_pointer_value(env, insn->src_reg)) {
+ verbose(env, "R%d pointer comparison prohibited\n",
+ insn->src_reg);
+ return -EACCES;
+ }
+ } else {
+ if (insn->src_reg != BPF_REG_0) {
+ verbose(env, "BPF_JMP/JMP32 uses reserved fields\n");
+ return -EINVAL;
+ }
+ }
+
+ is_jmp32 = BPF_CLASS(insn->code) == BPF_JMP32;
+
+ if (BPF_SRC(insn->code) == BPF_K) {
+ pred = is_branch_taken(dst_reg, insn->imm, opcode, is_jmp32);
+ } else if (src_reg->type == SCALAR_VALUE &&
+ is_jmp32 && tnum_is_const(tnum_subreg(src_reg->var_off))) {
+ pred = is_branch_taken(dst_reg,
+ tnum_subreg(src_reg->var_off).value,
+ opcode,
+ is_jmp32);
+ } else if (src_reg->type == SCALAR_VALUE &&
+ !is_jmp32 && tnum_is_const(src_reg->var_off)) {
+ pred = is_branch_taken(dst_reg,
+ src_reg->var_off.value,
+ opcode,
+ is_jmp32);
+ } else if (dst_reg->type == SCALAR_VALUE &&
+ is_jmp32 && tnum_is_const(tnum_subreg(dst_reg->var_off))) {
+ pred = is_branch_taken(src_reg,
+ tnum_subreg(dst_reg->var_off).value,
+ flip_opcode(opcode),
+ is_jmp32);
+ } else if (dst_reg->type == SCALAR_VALUE &&
+ !is_jmp32 && tnum_is_const(dst_reg->var_off)) {
+ pred = is_branch_taken(src_reg,
+ dst_reg->var_off.value,
+ flip_opcode(opcode),
+ is_jmp32);
+ } else if (reg_is_pkt_pointer_any(dst_reg) &&
+ reg_is_pkt_pointer_any(src_reg) &&
+ !is_jmp32) {
+ pred = is_pkt_ptr_branch_taken(dst_reg, src_reg, opcode);
+ }
+
+ if (pred >= 0) {
+ /* If we get here with a dst_reg pointer type it is because
+ * above is_branch_taken() special cased the 0 comparison.
+ */
+ if (!__is_pointer_value(false, dst_reg))
+ err = mark_chain_precision(env, insn->dst_reg);
+ if (BPF_SRC(insn->code) == BPF_X && !err &&
+ !__is_pointer_value(false, src_reg))
+ err = mark_chain_precision(env, insn->src_reg);
+ if (err)
+ return err;
+ }
+
+ if (pred == 1) {
+ /* Only follow the goto, ignore fall-through. If needed, push
+ * the fall-through branch for simulation under speculative
+ * execution.
+ */
+ if (!env->bypass_spec_v1 &&
+ !sanitize_speculative_path(env, insn, *insn_idx + 1,
+ *insn_idx))
+ return -EFAULT;
+ if (env->log.level & BPF_LOG_LEVEL)
+ print_insn_state(env, this_branch->frame[this_branch->curframe]);
+ *insn_idx += insn->off;
+ return 0;
+ } else if (pred == 0) {
+ /* Only follow the fall-through branch, since that's where the
+ * program will go. If needed, push the goto branch for
+ * simulation under speculative execution.
+ */
+ if (!env->bypass_spec_v1 &&
+ !sanitize_speculative_path(env, insn,
+ *insn_idx + insn->off + 1,
+ *insn_idx))
+ return -EFAULT;
+ if (env->log.level & BPF_LOG_LEVEL)
+ print_insn_state(env, this_branch->frame[this_branch->curframe]);
+ return 0;
+ }
+
+ other_branch = push_stack(env, *insn_idx + insn->off + 1, *insn_idx,
+ false);
+ if (!other_branch)
+ return -EFAULT;
+ other_branch_regs = other_branch->frame[other_branch->curframe]->regs;
+
+ /* detect if we are comparing against a constant value so we can adjust
+ * our min/max values for our dst register.
+ * this is only legit if both are scalars (or pointers to the same
+ * object, I suppose, see the PTR_MAYBE_NULL related if block below),
+ * because otherwise the different base pointers mean the offsets aren't
+ * comparable.
+ */
+ if (BPF_SRC(insn->code) == BPF_X) {
+ struct bpf_reg_state *src_reg = &regs[insn->src_reg];
+
+ if (dst_reg->type == SCALAR_VALUE &&
+ src_reg->type == SCALAR_VALUE) {
+ if (tnum_is_const(src_reg->var_off) ||
+ (is_jmp32 &&
+ tnum_is_const(tnum_subreg(src_reg->var_off))))
+ reg_set_min_max(&other_branch_regs[insn->dst_reg],
+ dst_reg,
+ src_reg->var_off.value,
+ tnum_subreg(src_reg->var_off).value,
+ opcode, is_jmp32);
+ else if (tnum_is_const(dst_reg->var_off) ||
+ (is_jmp32 &&
+ tnum_is_const(tnum_subreg(dst_reg->var_off))))
+ reg_set_min_max_inv(&other_branch_regs[insn->src_reg],
+ src_reg,
+ dst_reg->var_off.value,
+ tnum_subreg(dst_reg->var_off).value,
+ opcode, is_jmp32);
+ else if (!is_jmp32 &&
+ (opcode == BPF_JEQ || opcode == BPF_JNE))
+ /* Comparing for equality, we can combine knowledge */
+ reg_combine_min_max(&other_branch_regs[insn->src_reg],
+ &other_branch_regs[insn->dst_reg],
+ src_reg, dst_reg, opcode);
+ if (src_reg->id &&
+ !WARN_ON_ONCE(src_reg->id != other_branch_regs[insn->src_reg].id)) {
+ find_equal_scalars(this_branch, src_reg);
+ find_equal_scalars(other_branch, &other_branch_regs[insn->src_reg]);
+ }
+
+ }
+ } else if (dst_reg->type == SCALAR_VALUE) {
+ reg_set_min_max(&other_branch_regs[insn->dst_reg],
+ dst_reg, insn->imm, (u32)insn->imm,
+ opcode, is_jmp32);
+ }
+
+ if (dst_reg->type == SCALAR_VALUE && dst_reg->id &&
+ !WARN_ON_ONCE(dst_reg->id != other_branch_regs[insn->dst_reg].id)) {
+ find_equal_scalars(this_branch, dst_reg);
+ find_equal_scalars(other_branch, &other_branch_regs[insn->dst_reg]);
+ }
+
+ /* if one pointer register is compared to another pointer
+ * register check if PTR_MAYBE_NULL could be lifted.
+ * E.g. register A - maybe null
+ * register B - not null
+ * for JNE A, B, ... - A is not null in the false branch;
+ * for JEQ A, B, ... - A is not null in the true branch.
+ *
+ * Since PTR_TO_BTF_ID points to a kernel struct that does
+ * not need to be null checked by the BPF program, i.e.,
+ * could be null even without PTR_MAYBE_NULL marking, so
+ * only propagate nullness when neither reg is that type.
+ */
+ if (!is_jmp32 && BPF_SRC(insn->code) == BPF_X &&
+ __is_pointer_value(false, src_reg) && __is_pointer_value(false, dst_reg) &&
+ type_may_be_null(src_reg->type) != type_may_be_null(dst_reg->type) &&
+ base_type(src_reg->type) != PTR_TO_BTF_ID &&
+ base_type(dst_reg->type) != PTR_TO_BTF_ID) {
+ eq_branch_regs = NULL;
+ switch (opcode) {
+ case BPF_JEQ:
+ eq_branch_regs = other_branch_regs;
+ break;
+ case BPF_JNE:
+ eq_branch_regs = regs;
+ break;
+ default:
+ /* do nothing */
+ break;
+ }
+ if (eq_branch_regs) {
+ if (type_may_be_null(src_reg->type))
+ mark_ptr_not_null_reg(&eq_branch_regs[insn->src_reg]);
+ else
+ mark_ptr_not_null_reg(&eq_branch_regs[insn->dst_reg]);
+ }
+ }
+
+ /* detect if R == 0 where R is returned from bpf_map_lookup_elem().
+ * NOTE: these optimizations below are related with pointer comparison
+ * which will never be JMP32.
+ */
+ if (!is_jmp32 && BPF_SRC(insn->code) == BPF_K &&
+ insn->imm == 0 && (opcode == BPF_JEQ || opcode == BPF_JNE) &&
+ type_may_be_null(dst_reg->type)) {
+ /* Mark all identical registers in each branch as either
+ * safe or unknown depending R == 0 or R != 0 conditional.
+ */
+ mark_ptr_or_null_regs(this_branch, insn->dst_reg,
+ opcode == BPF_JNE);
+ mark_ptr_or_null_regs(other_branch, insn->dst_reg,
+ opcode == BPF_JEQ);
+ } else if (!try_match_pkt_pointers(insn, dst_reg, &regs[insn->src_reg],
+ this_branch, other_branch) &&
+ is_pointer_value(env, insn->dst_reg)) {
+ verbose(env, "R%d pointer comparison prohibited\n",
+ insn->dst_reg);
+ return -EACCES;
+ }
+ if (env->log.level & BPF_LOG_LEVEL)
+ print_insn_state(env, this_branch->frame[this_branch->curframe]);
+ return 0;
+}
+
+/* verify BPF_LD_IMM64 instruction */
+static int check_ld_imm(struct bpf_verifier_env *env, struct bpf_insn *insn)
+{
+ struct bpf_insn_aux_data *aux = cur_aux(env);
+ struct bpf_reg_state *regs = cur_regs(env);
+ struct bpf_reg_state *dst_reg;
+ struct bpf_map *map;
+ int err;
+
+ if (BPF_SIZE(insn->code) != BPF_DW) {
+ verbose(env, "invalid BPF_LD_IMM insn\n");
+ return -EINVAL;
+ }
+ if (insn->off != 0) {
+ verbose(env, "BPF_LD_IMM64 uses reserved fields\n");
+ return -EINVAL;
+ }
+
+ err = check_reg_arg(env, insn->dst_reg, DST_OP);
+ if (err)
+ return err;
+
+ dst_reg = &regs[insn->dst_reg];
+ if (insn->src_reg == 0) {
+ u64 imm = ((u64)(insn + 1)->imm << 32) | (u32)insn->imm;
+
+ dst_reg->type = SCALAR_VALUE;
+ __mark_reg_known(&regs[insn->dst_reg], imm);
+ return 0;
+ }
+
+ /* All special src_reg cases are listed below. From this point onwards
+ * we either succeed and assign a corresponding dst_reg->type after
+ * zeroing the offset, or fail and reject the program.
+ */
+ mark_reg_known_zero(env, regs, insn->dst_reg);
+
+ if (insn->src_reg == BPF_PSEUDO_BTF_ID) {
+ dst_reg->type = aux->btf_var.reg_type;
+ switch (base_type(dst_reg->type)) {
+ case PTR_TO_MEM:
+ dst_reg->mem_size = aux->btf_var.mem_size;
+ break;
+ case PTR_TO_BTF_ID:
+ dst_reg->btf = aux->btf_var.btf;
+ dst_reg->btf_id = aux->btf_var.btf_id;
+ break;
+ default:
+ verbose(env, "bpf verifier is misconfigured\n");
+ return -EFAULT;
+ }
+ return 0;
+ }
+
+ if (insn->src_reg == BPF_PSEUDO_FUNC) {
+ struct bpf_prog_aux *aux = env->prog->aux;
+ u32 subprogno = find_subprog(env,
+ env->insn_idx + insn->imm + 1);
+
+ if (!aux->func_info) {
+ verbose(env, "missing btf func_info\n");
+ return -EINVAL;
+ }
+ if (aux->func_info_aux[subprogno].linkage != BTF_FUNC_STATIC) {
+ verbose(env, "callback function not static\n");
+ return -EINVAL;
+ }
+
+ dst_reg->type = PTR_TO_FUNC;
+ dst_reg->subprogno = subprogno;
+ return 0;
+ }
+
+ map = env->used_maps[aux->map_index];
+ dst_reg->map_ptr = map;
+
+ if (insn->src_reg == BPF_PSEUDO_MAP_VALUE ||
+ insn->src_reg == BPF_PSEUDO_MAP_IDX_VALUE) {
+ dst_reg->type = PTR_TO_MAP_VALUE;
+ dst_reg->off = aux->map_off;
+ WARN_ON_ONCE(map->max_entries != 1);
+ /* We want reg->id to be same (0) as map_value is not distinct */
+ } else if (insn->src_reg == BPF_PSEUDO_MAP_FD ||
+ insn->src_reg == BPF_PSEUDO_MAP_IDX) {
+ dst_reg->type = CONST_PTR_TO_MAP;
+ } else {
+ verbose(env, "bpf verifier is misconfigured\n");
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
+static bool may_access_skb(enum bpf_prog_type type)
+{
+ switch (type) {
+ case BPF_PROG_TYPE_SOCKET_FILTER:
+ case BPF_PROG_TYPE_SCHED_CLS:
+ case BPF_PROG_TYPE_SCHED_ACT:
+ return true;
+ default:
+ return false;
+ }
+}
+
+/* verify safety of LD_ABS|LD_IND instructions:
+ * - they can only appear in the programs where ctx == skb
+ * - since they are wrappers of function calls, they scratch R1-R5 registers,
+ * preserve R6-R9, and store return value into R0
+ *
+ * Implicit input:
+ * ctx == skb == R6 == CTX
+ *
+ * Explicit input:
+ * SRC == any register
+ * IMM == 32-bit immediate
+ *
+ * Output:
+ * R0 - 8/16/32-bit skb data converted to cpu endianness
+ */
+static int check_ld_abs(struct bpf_verifier_env *env, struct bpf_insn *insn)
+{
+ struct bpf_reg_state *regs = cur_regs(env);
+ static const int ctx_reg = BPF_REG_6;
+ u8 mode = BPF_MODE(insn->code);
+ int i, err;
+
+ if (!may_access_skb(resolve_prog_type(env->prog))) {
+ verbose(env, "BPF_LD_[ABS|IND] instructions not allowed for this program type\n");
+ return -EINVAL;
+ }
+
+ if (!env->ops->gen_ld_abs) {
+ verbose(env, "bpf verifier is misconfigured\n");
+ return -EINVAL;
+ }
+
+ if (insn->dst_reg != BPF_REG_0 || insn->off != 0 ||
+ BPF_SIZE(insn->code) == BPF_DW ||
+ (mode == BPF_ABS && insn->src_reg != BPF_REG_0)) {
+ verbose(env, "BPF_LD_[ABS|IND] uses reserved fields\n");
+ return -EINVAL;
+ }
+
+ /* check whether implicit source operand (register R6) is readable */
+ err = check_reg_arg(env, ctx_reg, SRC_OP);
+ if (err)
+ return err;
+
+ /* Disallow usage of BPF_LD_[ABS|IND] with reference tracking, as
+ * gen_ld_abs() may terminate the program at runtime, leading to
+ * reference leak.
+ */
+ err = check_reference_leak(env);
+ if (err) {
+ verbose(env, "BPF_LD_[ABS|IND] cannot be mixed with socket references\n");
+ return err;
+ }
+
+ if (env->cur_state->active_lock.ptr) {
+ verbose(env, "BPF_LD_[ABS|IND] cannot be used inside bpf_spin_lock-ed region\n");
+ return -EINVAL;
+ }
+
+ if (env->cur_state->active_rcu_lock) {
+ verbose(env, "BPF_LD_[ABS|IND] cannot be used inside bpf_rcu_read_lock-ed region\n");
+ return -EINVAL;
+ }
+
+ if (regs[ctx_reg].type != PTR_TO_CTX) {
+ verbose(env,
+ "at the time of BPF_LD_ABS|IND R6 != pointer to skb\n");
+ return -EINVAL;
+ }
+
+ if (mode == BPF_IND) {
+ /* check explicit source operand */
+ err = check_reg_arg(env, insn->src_reg, SRC_OP);
+ if (err)
+ return err;
+ }
+
+ err = check_ptr_off_reg(env, &regs[ctx_reg], ctx_reg);
+ if (err < 0)
+ return err;
+
+ /* reset caller saved regs to unreadable */
+ for (i = 0; i < CALLER_SAVED_REGS; i++) {
+ mark_reg_not_init(env, regs, caller_saved[i]);
+ check_reg_arg(env, caller_saved[i], DST_OP_NO_MARK);
+ }
+
+ /* mark destination R0 register as readable, since it contains
+ * the value fetched from the packet.
+ * Already marked as written above.
+ */
+ mark_reg_unknown(env, regs, BPF_REG_0);
+ /* ld_abs load up to 32-bit skb data. */
+ regs[BPF_REG_0].subreg_def = env->insn_idx + 1;
+ return 0;
+}
+
+static int check_return_code(struct bpf_verifier_env *env)
+{
+ struct tnum enforce_attach_type_range = tnum_unknown;
+ const struct bpf_prog *prog = env->prog;
+ struct bpf_reg_state *reg;
+ struct tnum range = tnum_range(0, 1), const_0 = tnum_const(0);
+ enum bpf_prog_type prog_type = resolve_prog_type(env->prog);
+ int err;
+ struct bpf_func_state *frame = env->cur_state->frame[0];
+ const bool is_subprog = frame->subprogno;
+
+ /* LSM and struct_ops func-ptr's return type could be "void" */
+ if (!is_subprog) {
+ switch (prog_type) {
+ case BPF_PROG_TYPE_LSM:
+ if (prog->expected_attach_type == BPF_LSM_CGROUP)
+ /* See below, can be 0 or 0-1 depending on hook. */
+ break;
+ fallthrough;
+ case BPF_PROG_TYPE_STRUCT_OPS:
+ if (!prog->aux->attach_func_proto->type)
+ return 0;
+ break;
+ default:
+ break;
+ }
+ }
+
+ /* eBPF calling convention is such that R0 is used
+ * to return the value from eBPF program.
+ * Make sure that it's readable at this time
+ * of bpf_exit, which means that program wrote
+ * something into it earlier
+ */
+ err = check_reg_arg(env, BPF_REG_0, SRC_OP);
+ if (err)
+ return err;
+
+ if (is_pointer_value(env, BPF_REG_0)) {
+ verbose(env, "R0 leaks addr as return value\n");
+ return -EACCES;
+ }
+
+ reg = cur_regs(env) + BPF_REG_0;
+
+ if (frame->in_async_callback_fn) {
+ /* enforce return zero from async callbacks like timer */
+ if (reg->type != SCALAR_VALUE) {
+ verbose(env, "In async callback the register R0 is not a known value (%s)\n",
+ reg_type_str(env, reg->type));
+ return -EINVAL;
+ }
+
+ if (!tnum_in(const_0, reg->var_off)) {
+ verbose_invalid_scalar(env, reg, &const_0, "async callback", "R0");
+ return -EINVAL;
+ }
+ return 0;
+ }
+
+ if (is_subprog) {
+ if (reg->type != SCALAR_VALUE) {
+ verbose(env, "At subprogram exit the register R0 is not a scalar value (%s)\n",
+ reg_type_str(env, reg->type));
+ return -EINVAL;
+ }
+ return 0;
+ }
+
+ switch (prog_type) {
+ case BPF_PROG_TYPE_CGROUP_SOCK_ADDR:
+ if (env->prog->expected_attach_type == BPF_CGROUP_UDP4_RECVMSG ||
+ env->prog->expected_attach_type == BPF_CGROUP_UDP6_RECVMSG ||
+ env->prog->expected_attach_type == BPF_CGROUP_INET4_GETPEERNAME ||
+ env->prog->expected_attach_type == BPF_CGROUP_INET6_GETPEERNAME ||
+ env->prog->expected_attach_type == BPF_CGROUP_INET4_GETSOCKNAME ||
+ env->prog->expected_attach_type == BPF_CGROUP_INET6_GETSOCKNAME)
+ range = tnum_range(1, 1);
+ if (env->prog->expected_attach_type == BPF_CGROUP_INET4_BIND ||
+ env->prog->expected_attach_type == BPF_CGROUP_INET6_BIND)
+ range = tnum_range(0, 3);
+ break;
+ case BPF_PROG_TYPE_CGROUP_SKB:
+ if (env->prog->expected_attach_type == BPF_CGROUP_INET_EGRESS) {
+ range = tnum_range(0, 3);
+ enforce_attach_type_range = tnum_range(2, 3);
+ }
+ break;
+ case BPF_PROG_TYPE_CGROUP_SOCK:
+ case BPF_PROG_TYPE_SOCK_OPS:
+ case BPF_PROG_TYPE_CGROUP_DEVICE:
+ case BPF_PROG_TYPE_CGROUP_SYSCTL:
+ case BPF_PROG_TYPE_CGROUP_SOCKOPT:
+ break;
+ case BPF_PROG_TYPE_RAW_TRACEPOINT:
+ if (!env->prog->aux->attach_btf_id)
+ return 0;
+ range = tnum_const(0);
+ break;
+ case BPF_PROG_TYPE_TRACING:
+ switch (env->prog->expected_attach_type) {
+ case BPF_TRACE_FENTRY:
+ case BPF_TRACE_FEXIT:
+ range = tnum_const(0);
+ break;
+ case BPF_TRACE_RAW_TP:
+ case BPF_MODIFY_RETURN:
+ return 0;
+ case BPF_TRACE_ITER:
+ break;
+ default:
+ return -ENOTSUPP;
+ }
+ break;
+ case BPF_PROG_TYPE_SK_LOOKUP:
+ range = tnum_range(SK_DROP, SK_PASS);
+ break;
+
+ case BPF_PROG_TYPE_LSM:
+ if (env->prog->expected_attach_type != BPF_LSM_CGROUP) {
+ /* Regular BPF_PROG_TYPE_LSM programs can return
+ * any value.
+ */
+ return 0;
+ }
+ if (!env->prog->aux->attach_func_proto->type) {
+ /* Make sure programs that attach to void
+ * hooks don't try to modify return value.
+ */
+ range = tnum_range(1, 1);
+ }
+ break;
+
+ case BPF_PROG_TYPE_NETFILTER:
+ range = tnum_range(NF_DROP, NF_ACCEPT);
+ break;
+ case BPF_PROG_TYPE_EXT:
+ /* freplace program can return anything as its return value
+ * depends on the to-be-replaced kernel func or bpf program.
+ */
+ default:
+ return 0;
+ }
+
+ if (reg->type != SCALAR_VALUE) {
+ verbose(env, "At program exit the register R0 is not a known value (%s)\n",
+ reg_type_str(env, reg->type));
+ return -EINVAL;
+ }
+
+ if (!tnum_in(range, reg->var_off)) {
+ verbose_invalid_scalar(env, reg, &range, "program exit", "R0");
+ if (prog->expected_attach_type == BPF_LSM_CGROUP &&
+ prog_type == BPF_PROG_TYPE_LSM &&
+ !prog->aux->attach_func_proto->type)
+ verbose(env, "Note, BPF_LSM_CGROUP that attach to void LSM hooks can't modify return value!\n");
+ return -EINVAL;
+ }
+
+ if (!tnum_is_unknown(enforce_attach_type_range) &&
+ tnum_in(enforce_attach_type_range, reg->var_off))
+ env->prog->enforce_expected_attach_type = 1;
+ return 0;
+}
+
+/* non-recursive DFS pseudo code
+ * 1 procedure DFS-iterative(G,v):
+ * 2 label v as discovered
+ * 3 let S be a stack
+ * 4 S.push(v)
+ * 5 while S is not empty
+ * 6 t <- S.peek()
+ * 7 if t is what we're looking for:
+ * 8 return t
+ * 9 for all edges e in G.adjacentEdges(t) do
+ * 10 if edge e is already labelled
+ * 11 continue with the next edge
+ * 12 w <- G.adjacentVertex(t,e)
+ * 13 if vertex w is not discovered and not explored
+ * 14 label e as tree-edge
+ * 15 label w as discovered
+ * 16 S.push(w)
+ * 17 continue at 5
+ * 18 else if vertex w is discovered
+ * 19 label e as back-edge
+ * 20 else
+ * 21 // vertex w is explored
+ * 22 label e as forward- or cross-edge
+ * 23 label t as explored
+ * 24 S.pop()
+ *
+ * convention:
+ * 0x10 - discovered
+ * 0x11 - discovered and fall-through edge labelled
+ * 0x12 - discovered and fall-through and branch edges labelled
+ * 0x20 - explored
+ */
+
+enum {
+ DISCOVERED = 0x10,
+ EXPLORED = 0x20,
+ FALLTHROUGH = 1,
+ BRANCH = 2,
+};
+
+static void mark_prune_point(struct bpf_verifier_env *env, int idx)
+{
+ env->insn_aux_data[idx].prune_point = true;
+}
+
+static bool is_prune_point(struct bpf_verifier_env *env, int insn_idx)
+{
+ return env->insn_aux_data[insn_idx].prune_point;
+}
+
+static void mark_force_checkpoint(struct bpf_verifier_env *env, int idx)
+{
+ env->insn_aux_data[idx].force_checkpoint = true;
+}
+
+static bool is_force_checkpoint(struct bpf_verifier_env *env, int insn_idx)
+{
+ return env->insn_aux_data[insn_idx].force_checkpoint;
+}
+
+static void mark_calls_callback(struct bpf_verifier_env *env, int idx)
+{
+ env->insn_aux_data[idx].calls_callback = true;
+}
+
+static bool calls_callback(struct bpf_verifier_env *env, int insn_idx)
+{
+ return env->insn_aux_data[insn_idx].calls_callback;
+}
+
+enum {
+ DONE_EXPLORING = 0,
+ KEEP_EXPLORING = 1,
+};
+
+/* t, w, e - match pseudo-code above:
+ * t - index of current instruction
+ * w - next instruction
+ * e - edge
+ */
+static int push_insn(int t, int w, int e, struct bpf_verifier_env *env)
+{
+ int *insn_stack = env->cfg.insn_stack;
+ int *insn_state = env->cfg.insn_state;
+
+ if (e == FALLTHROUGH && insn_state[t] >= (DISCOVERED | FALLTHROUGH))
+ return DONE_EXPLORING;
+
+ if (e == BRANCH && insn_state[t] >= (DISCOVERED | BRANCH))
+ return DONE_EXPLORING;
+
+ if (w < 0 || w >= env->prog->len) {
+ verbose_linfo(env, t, "%d: ", t);
+ verbose(env, "jump out of range from insn %d to %d\n", t, w);
+ return -EINVAL;
+ }
+
+ if (e == BRANCH) {
+ /* mark branch target for state pruning */
+ mark_prune_point(env, w);
+ mark_jmp_point(env, w);
+ }
+
+ if (insn_state[w] == 0) {
+ /* tree-edge */
+ insn_state[t] = DISCOVERED | e;
+ insn_state[w] = DISCOVERED;
+ if (env->cfg.cur_stack >= env->prog->len)
+ return -E2BIG;
+ insn_stack[env->cfg.cur_stack++] = w;
+ return KEEP_EXPLORING;
+ } else if ((insn_state[w] & 0xF0) == DISCOVERED) {
+ if (env->bpf_capable)
+ return DONE_EXPLORING;
+ verbose_linfo(env, t, "%d: ", t);
+ verbose_linfo(env, w, "%d: ", w);
+ verbose(env, "back-edge from insn %d to %d\n", t, w);
+ return -EINVAL;
+ } else if (insn_state[w] == EXPLORED) {
+ /* forward- or cross-edge */
+ insn_state[t] = DISCOVERED | e;
+ } else {
+ verbose(env, "insn state internal bug\n");
+ return -EFAULT;
+ }
+ return DONE_EXPLORING;
+}
+
+static int visit_func_call_insn(int t, struct bpf_insn *insns,
+ struct bpf_verifier_env *env,
+ bool visit_callee)
+{
+ int ret, insn_sz;
+
+ insn_sz = bpf_is_ldimm64(&insns[t]) ? 2 : 1;
+ ret = push_insn(t, t + insn_sz, FALLTHROUGH, env);
+ if (ret)
+ return ret;
+
+ mark_prune_point(env, t + insn_sz);
+ /* when we exit from subprog, we need to record non-linear history */
+ mark_jmp_point(env, t + insn_sz);
+
+ if (visit_callee) {
+ mark_prune_point(env, t);
+ ret = push_insn(t, t + insns[t].imm + 1, BRANCH, env);
+ }
+ return ret;
+}
+
+/* Visits the instruction at index t and returns one of the following:
+ * < 0 - an error occurred
+ * DONE_EXPLORING - the instruction was fully explored
+ * KEEP_EXPLORING - there is still work to be done before it is fully explored
+ */
+static int visit_insn(int t, struct bpf_verifier_env *env)
+{
+ struct bpf_insn *insns = env->prog->insnsi, *insn = &insns[t];
+ int ret, off, insn_sz;
+
+ if (bpf_pseudo_func(insn))
+ return visit_func_call_insn(t, insns, env, true);
+
+ /* All non-branch instructions have a single fall-through edge. */
+ if (BPF_CLASS(insn->code) != BPF_JMP &&
+ BPF_CLASS(insn->code) != BPF_JMP32) {
+ insn_sz = bpf_is_ldimm64(insn) ? 2 : 1;
+ return push_insn(t, t + insn_sz, FALLTHROUGH, env);
+ }
+
+ switch (BPF_OP(insn->code)) {
+ case BPF_EXIT:
+ return DONE_EXPLORING;
+
+ case BPF_CALL:
+ if (insn->src_reg == 0 && insn->imm == BPF_FUNC_timer_set_callback)
+ /* Mark this call insn as a prune point to trigger
+ * is_state_visited() check before call itself is
+ * processed by __check_func_call(). Otherwise new
+ * async state will be pushed for further exploration.
+ */
+ mark_prune_point(env, t);
+ /* For functions that invoke callbacks it is not known how many times
+ * callback would be called. Verifier models callback calling functions
+ * by repeatedly visiting callback bodies and returning to origin call
+ * instruction.
+ * In order to stop such iteration verifier needs to identify when a
+ * state identical some state from a previous iteration is reached.
+ * Check below forces creation of checkpoint before callback calling
+ * instruction to allow search for such identical states.
+ */
+ if (is_sync_callback_calling_insn(insn)) {
+ mark_calls_callback(env, t);
+ mark_force_checkpoint(env, t);
+ mark_prune_point(env, t);
+ mark_jmp_point(env, t);
+ }
+ if (insn->src_reg == BPF_PSEUDO_KFUNC_CALL) {
+ struct bpf_kfunc_call_arg_meta meta;
+
+ ret = fetch_kfunc_meta(env, insn, &meta, NULL);
+ if (ret == 0 && is_iter_next_kfunc(&meta)) {
+ mark_prune_point(env, t);
+ /* Checking and saving state checkpoints at iter_next() call
+ * is crucial for fast convergence of open-coded iterator loop
+ * logic, so we need to force it. If we don't do that,
+ * is_state_visited() might skip saving a checkpoint, causing
+ * unnecessarily long sequence of not checkpointed
+ * instructions and jumps, leading to exhaustion of jump
+ * history buffer, and potentially other undesired outcomes.
+ * It is expected that with correct open-coded iterators
+ * convergence will happen quickly, so we don't run a risk of
+ * exhausting memory.
+ */
+ mark_force_checkpoint(env, t);
+ }
+ }
+ return visit_func_call_insn(t, insns, env, insn->src_reg == BPF_PSEUDO_CALL);
+
+ case BPF_JA:
+ if (BPF_SRC(insn->code) != BPF_K)
+ return -EINVAL;
+
+ if (BPF_CLASS(insn->code) == BPF_JMP)
+ off = insn->off;
+ else
+ off = insn->imm;
+
+ /* unconditional jump with single edge */
+ ret = push_insn(t, t + off + 1, FALLTHROUGH, env);
+ if (ret)
+ return ret;
+
+ mark_prune_point(env, t + off + 1);
+ mark_jmp_point(env, t + off + 1);
+
+ return ret;
+
+ default:
+ /* conditional jump with two edges */
+ mark_prune_point(env, t);
+
+ ret = push_insn(t, t + 1, FALLTHROUGH, env);
+ if (ret)
+ return ret;
+
+ return push_insn(t, t + insn->off + 1, BRANCH, env);
+ }
+}
+
+/* non-recursive depth-first-search to detect loops in BPF program
+ * loop == back-edge in directed graph
+ */
+static int check_cfg(struct bpf_verifier_env *env)
+{
+ int insn_cnt = env->prog->len;
+ int *insn_stack, *insn_state;
+ int ret = 0;
+ int i;
+
+ insn_state = env->cfg.insn_state = kvcalloc(insn_cnt, sizeof(int), GFP_KERNEL);
+ if (!insn_state)
+ return -ENOMEM;
+
+ insn_stack = env->cfg.insn_stack = kvcalloc(insn_cnt, sizeof(int), GFP_KERNEL);
+ if (!insn_stack) {
+ kvfree(insn_state);
+ return -ENOMEM;
+ }
+
+ insn_state[0] = DISCOVERED; /* mark 1st insn as discovered */
+ insn_stack[0] = 0; /* 0 is the first instruction */
+ env->cfg.cur_stack = 1;
+
+ while (env->cfg.cur_stack > 0) {
+ int t = insn_stack[env->cfg.cur_stack - 1];
+
+ ret = visit_insn(t, env);
+ switch (ret) {
+ case DONE_EXPLORING:
+ insn_state[t] = EXPLORED;
+ env->cfg.cur_stack--;
+ break;
+ case KEEP_EXPLORING:
+ break;
+ default:
+ if (ret > 0) {
+ verbose(env, "visit_insn internal bug\n");
+ ret = -EFAULT;
+ }
+ goto err_free;
+ }
+ }
+
+ if (env->cfg.cur_stack < 0) {
+ verbose(env, "pop stack internal bug\n");
+ ret = -EFAULT;
+ goto err_free;
+ }
+
+ for (i = 0; i < insn_cnt; i++) {
+ struct bpf_insn *insn = &env->prog->insnsi[i];
+
+ if (insn_state[i] != EXPLORED) {
+ verbose(env, "unreachable insn %d\n", i);
+ ret = -EINVAL;
+ goto err_free;
+ }
+ if (bpf_is_ldimm64(insn)) {
+ if (insn_state[i + 1] != 0) {
+ verbose(env, "jump into the middle of ldimm64 insn %d\n", i);
+ ret = -EINVAL;
+ goto err_free;
+ }
+ i++; /* skip second half of ldimm64 */
+ }
+ }
+ ret = 0; /* cfg looks good */
+
+err_free:
+ kvfree(insn_state);
+ kvfree(insn_stack);
+ env->cfg.insn_state = env->cfg.insn_stack = NULL;
+ return ret;
+}
+
+static int check_abnormal_return(struct bpf_verifier_env *env)
+{
+ int i;
+
+ for (i = 1; i < env->subprog_cnt; i++) {
+ if (env->subprog_info[i].has_ld_abs) {
+ verbose(env, "LD_ABS is not allowed in subprogs without BTF\n");
+ return -EINVAL;
+ }
+ if (env->subprog_info[i].has_tail_call) {
+ verbose(env, "tail_call is not allowed in subprogs without BTF\n");
+ return -EINVAL;
+ }
+ }
+ return 0;
+}
+
+/* The minimum supported BTF func info size */
+#define MIN_BPF_FUNCINFO_SIZE 8
+#define MAX_FUNCINFO_REC_SIZE 252
+
+static int check_btf_func(struct bpf_verifier_env *env,
+ const union bpf_attr *attr,
+ bpfptr_t uattr)
+{
+ const struct btf_type *type, *func_proto, *ret_type;
+ u32 i, nfuncs, urec_size, min_size;
+ u32 krec_size = sizeof(struct bpf_func_info);
+ struct bpf_func_info *krecord;
+ struct bpf_func_info_aux *info_aux = NULL;
+ struct bpf_prog *prog;
+ const struct btf *btf;
+ bpfptr_t urecord;
+ u32 prev_offset = 0;
+ bool scalar_return;
+ int ret = -ENOMEM;
+
+ nfuncs = attr->func_info_cnt;
+ if (!nfuncs) {
+ if (check_abnormal_return(env))
+ return -EINVAL;
+ return 0;
+ }
+
+ if (nfuncs != env->subprog_cnt) {
+ verbose(env, "number of funcs in func_info doesn't match number of subprogs\n");
+ return -EINVAL;
+ }
+
+ urec_size = attr->func_info_rec_size;
+ if (urec_size < MIN_BPF_FUNCINFO_SIZE ||
+ urec_size > MAX_FUNCINFO_REC_SIZE ||
+ urec_size % sizeof(u32)) {
+ verbose(env, "invalid func info rec size %u\n", urec_size);
+ return -EINVAL;
+ }
+
+ prog = env->prog;
+ btf = prog->aux->btf;
+
+ urecord = make_bpfptr(attr->func_info, uattr.is_kernel);
+ min_size = min_t(u32, krec_size, urec_size);
+
+ krecord = kvcalloc(nfuncs, krec_size, GFP_KERNEL | __GFP_NOWARN);
+ if (!krecord)
+ return -ENOMEM;
+ info_aux = kcalloc(nfuncs, sizeof(*info_aux), GFP_KERNEL | __GFP_NOWARN);
+ if (!info_aux)
+ goto err_free;
+
+ for (i = 0; i < nfuncs; i++) {
+ ret = bpf_check_uarg_tail_zero(urecord, krec_size, urec_size);
+ if (ret) {
+ if (ret == -E2BIG) {
+ verbose(env, "nonzero tailing record in func info");
+ /* set the size kernel expects so loader can zero
+ * out the rest of the record.
+ */
+ if (copy_to_bpfptr_offset(uattr,
+ offsetof(union bpf_attr, func_info_rec_size),
+ &min_size, sizeof(min_size)))
+ ret = -EFAULT;
+ }
+ goto err_free;
+ }
+
+ if (copy_from_bpfptr(&krecord[i], urecord, min_size)) {
+ ret = -EFAULT;
+ goto err_free;
+ }
+
+ /* check insn_off */
+ ret = -EINVAL;
+ if (i == 0) {
+ if (krecord[i].insn_off) {
+ verbose(env,
+ "nonzero insn_off %u for the first func info record",
+ krecord[i].insn_off);
+ goto err_free;
+ }
+ } else if (krecord[i].insn_off <= prev_offset) {
+ verbose(env,
+ "same or smaller insn offset (%u) than previous func info record (%u)",
+ krecord[i].insn_off, prev_offset);
+ goto err_free;
+ }
+
+ if (env->subprog_info[i].start != krecord[i].insn_off) {
+ verbose(env, "func_info BTF section doesn't match subprog layout in BPF program\n");
+ goto err_free;
+ }
+
+ /* check type_id */
+ type = btf_type_by_id(btf, krecord[i].type_id);
+ if (!type || !btf_type_is_func(type)) {
+ verbose(env, "invalid type id %d in func info",
+ krecord[i].type_id);
+ goto err_free;
+ }
+ info_aux[i].linkage = BTF_INFO_VLEN(type->info);
+
+ func_proto = btf_type_by_id(btf, type->type);
+ if (unlikely(!func_proto || !btf_type_is_func_proto(func_proto)))
+ /* btf_func_check() already verified it during BTF load */
+ goto err_free;
+ ret_type = btf_type_skip_modifiers(btf, func_proto->type, NULL);
+ scalar_return =
+ btf_type_is_small_int(ret_type) || btf_is_any_enum(ret_type);
+ if (i && !scalar_return && env->subprog_info[i].has_ld_abs) {
+ verbose(env, "LD_ABS is only allowed in functions that return 'int'.\n");
+ goto err_free;
+ }
+ if (i && !scalar_return && env->subprog_info[i].has_tail_call) {
+ verbose(env, "tail_call is only allowed in functions that return 'int'.\n");
+ goto err_free;
+ }
+
+ prev_offset = krecord[i].insn_off;
+ bpfptr_add(&urecord, urec_size);
+ }
+
+ prog->aux->func_info = krecord;
+ prog->aux->func_info_cnt = nfuncs;
+ prog->aux->func_info_aux = info_aux;
+ return 0;
+
+err_free:
+ kvfree(krecord);
+ kfree(info_aux);
+ return ret;
+}
+
+static void adjust_btf_func(struct bpf_verifier_env *env)
+{
+ struct bpf_prog_aux *aux = env->prog->aux;
+ int i;
+
+ if (!aux->func_info)
+ return;
+
+ for (i = 0; i < env->subprog_cnt; i++)
+ aux->func_info[i].insn_off = env->subprog_info[i].start;
+}
+
+#define MIN_BPF_LINEINFO_SIZE offsetofend(struct bpf_line_info, line_col)
+#define MAX_LINEINFO_REC_SIZE MAX_FUNCINFO_REC_SIZE
+
+static int check_btf_line(struct bpf_verifier_env *env,
+ const union bpf_attr *attr,
+ bpfptr_t uattr)
+{
+ u32 i, s, nr_linfo, ncopy, expected_size, rec_size, prev_offset = 0;
+ struct bpf_subprog_info *sub;
+ struct bpf_line_info *linfo;
+ struct bpf_prog *prog;
+ const struct btf *btf;
+ bpfptr_t ulinfo;
+ int err;
+
+ nr_linfo = attr->line_info_cnt;
+ if (!nr_linfo)
+ return 0;
+ if (nr_linfo > INT_MAX / sizeof(struct bpf_line_info))
+ return -EINVAL;
+
+ rec_size = attr->line_info_rec_size;
+ if (rec_size < MIN_BPF_LINEINFO_SIZE ||
+ rec_size > MAX_LINEINFO_REC_SIZE ||
+ rec_size & (sizeof(u32) - 1))
+ return -EINVAL;
+
+ /* Need to zero it in case the userspace may
+ * pass in a smaller bpf_line_info object.
+ */
+ linfo = kvcalloc(nr_linfo, sizeof(struct bpf_line_info),
+ GFP_KERNEL | __GFP_NOWARN);
+ if (!linfo)
+ return -ENOMEM;
+
+ prog = env->prog;
+ btf = prog->aux->btf;
+
+ s = 0;
+ sub = env->subprog_info;
+ ulinfo = make_bpfptr(attr->line_info, uattr.is_kernel);
+ expected_size = sizeof(struct bpf_line_info);
+ ncopy = min_t(u32, expected_size, rec_size);
+ for (i = 0; i < nr_linfo; i++) {
+ err = bpf_check_uarg_tail_zero(ulinfo, expected_size, rec_size);
+ if (err) {
+ if (err == -E2BIG) {
+ verbose(env, "nonzero tailing record in line_info");
+ if (copy_to_bpfptr_offset(uattr,
+ offsetof(union bpf_attr, line_info_rec_size),
+ &expected_size, sizeof(expected_size)))
+ err = -EFAULT;
+ }
+ goto err_free;
+ }
+
+ if (copy_from_bpfptr(&linfo[i], ulinfo, ncopy)) {
+ err = -EFAULT;
+ goto err_free;
+ }
+
+ /*
+ * Check insn_off to ensure
+ * 1) strictly increasing AND
+ * 2) bounded by prog->len
+ *
+ * The linfo[0].insn_off == 0 check logically falls into
+ * the later "missing bpf_line_info for func..." case
+ * because the first linfo[0].insn_off must be the
+ * first sub also and the first sub must have
+ * subprog_info[0].start == 0.
+ */
+ if ((i && linfo[i].insn_off <= prev_offset) ||
+ linfo[i].insn_off >= prog->len) {
+ verbose(env, "Invalid line_info[%u].insn_off:%u (prev_offset:%u prog->len:%u)\n",
+ i, linfo[i].insn_off, prev_offset,
+ prog->len);
+ err = -EINVAL;
+ goto err_free;
+ }
+
+ if (!prog->insnsi[linfo[i].insn_off].code) {
+ verbose(env,
+ "Invalid insn code at line_info[%u].insn_off\n",
+ i);
+ err = -EINVAL;
+ goto err_free;
+ }
+
+ if (!btf_name_by_offset(btf, linfo[i].line_off) ||
+ !btf_name_by_offset(btf, linfo[i].file_name_off)) {
+ verbose(env, "Invalid line_info[%u].line_off or .file_name_off\n", i);
+ err = -EINVAL;
+ goto err_free;
+ }
+
+ if (s != env->subprog_cnt) {
+ if (linfo[i].insn_off == sub[s].start) {
+ sub[s].linfo_idx = i;
+ s++;
+ } else if (sub[s].start < linfo[i].insn_off) {
+ verbose(env, "missing bpf_line_info for func#%u\n", s);
+ err = -EINVAL;
+ goto err_free;
+ }
+ }
+
+ prev_offset = linfo[i].insn_off;
+ bpfptr_add(&ulinfo, rec_size);
+ }
+
+ if (s != env->subprog_cnt) {
+ verbose(env, "missing bpf_line_info for %u funcs starting from func#%u\n",
+ env->subprog_cnt - s, s);
+ err = -EINVAL;
+ goto err_free;
+ }
+
+ prog->aux->linfo = linfo;
+ prog->aux->nr_linfo = nr_linfo;
+
+ return 0;
+
+err_free:
+ kvfree(linfo);
+ return err;
+}
+
+#define MIN_CORE_RELO_SIZE sizeof(struct bpf_core_relo)
+#define MAX_CORE_RELO_SIZE MAX_FUNCINFO_REC_SIZE
+
+static int check_core_relo(struct bpf_verifier_env *env,
+ const union bpf_attr *attr,
+ bpfptr_t uattr)
+{
+ u32 i, nr_core_relo, ncopy, expected_size, rec_size;
+ struct bpf_core_relo core_relo = {};
+ struct bpf_prog *prog = env->prog;
+ const struct btf *btf = prog->aux->btf;
+ struct bpf_core_ctx ctx = {
+ .log = &env->log,
+ .btf = btf,
+ };
+ bpfptr_t u_core_relo;
+ int err;
+
+ nr_core_relo = attr->core_relo_cnt;
+ if (!nr_core_relo)
+ return 0;
+ if (nr_core_relo > INT_MAX / sizeof(struct bpf_core_relo))
+ return -EINVAL;
+
+ rec_size = attr->core_relo_rec_size;
+ if (rec_size < MIN_CORE_RELO_SIZE ||
+ rec_size > MAX_CORE_RELO_SIZE ||
+ rec_size % sizeof(u32))
+ return -EINVAL;
+
+ u_core_relo = make_bpfptr(attr->core_relos, uattr.is_kernel);
+ expected_size = sizeof(struct bpf_core_relo);
+ ncopy = min_t(u32, expected_size, rec_size);
+
+ /* Unlike func_info and line_info, copy and apply each CO-RE
+ * relocation record one at a time.
+ */
+ for (i = 0; i < nr_core_relo; i++) {
+ /* future proofing when sizeof(bpf_core_relo) changes */
+ err = bpf_check_uarg_tail_zero(u_core_relo, expected_size, rec_size);
+ if (err) {
+ if (err == -E2BIG) {
+ verbose(env, "nonzero tailing record in core_relo");
+ if (copy_to_bpfptr_offset(uattr,
+ offsetof(union bpf_attr, core_relo_rec_size),
+ &expected_size, sizeof(expected_size)))
+ err = -EFAULT;
+ }
+ break;
+ }
+
+ if (copy_from_bpfptr(&core_relo, u_core_relo, ncopy)) {
+ err = -EFAULT;
+ break;
+ }
+
+ if (core_relo.insn_off % 8 || core_relo.insn_off / 8 >= prog->len) {
+ verbose(env, "Invalid core_relo[%u].insn_off:%u prog->len:%u\n",
+ i, core_relo.insn_off, prog->len);
+ err = -EINVAL;
+ break;
+ }
+
+ err = bpf_core_apply(&ctx, &core_relo, i,
+ &prog->insnsi[core_relo.insn_off / 8]);
+ if (err)
+ break;
+ bpfptr_add(&u_core_relo, rec_size);
+ }
+ return err;
+}
+
+static int check_btf_info(struct bpf_verifier_env *env,
+ const union bpf_attr *attr,
+ bpfptr_t uattr)
+{
+ struct btf *btf;
+ int err;
+
+ if (!attr->func_info_cnt && !attr->line_info_cnt) {
+ if (check_abnormal_return(env))
+ return -EINVAL;
+ return 0;
+ }
+
+ btf = btf_get_by_fd(attr->prog_btf_fd);
+ if (IS_ERR(btf))
+ return PTR_ERR(btf);
+ if (btf_is_kernel(btf)) {
+ btf_put(btf);
+ return -EACCES;
+ }
+ env->prog->aux->btf = btf;
+
+ err = check_btf_func(env, attr, uattr);
+ if (err)
+ return err;
+
+ err = check_btf_line(env, attr, uattr);
+ if (err)
+ return err;
+
+ err = check_core_relo(env, attr, uattr);
+ if (err)
+ return err;
+
+ return 0;
+}
+
+/* check %cur's range satisfies %old's */
+static bool range_within(struct bpf_reg_state *old,
+ struct bpf_reg_state *cur)
+{
+ return old->umin_value <= cur->umin_value &&
+ old->umax_value >= cur->umax_value &&
+ old->smin_value <= cur->smin_value &&
+ old->smax_value >= cur->smax_value &&
+ old->u32_min_value <= cur->u32_min_value &&
+ old->u32_max_value >= cur->u32_max_value &&
+ old->s32_min_value <= cur->s32_min_value &&
+ old->s32_max_value >= cur->s32_max_value;
+}
+
+/* If in the old state two registers had the same id, then they need to have
+ * the same id in the new state as well. But that id could be different from
+ * the old state, so we need to track the mapping from old to new ids.
+ * Once we have seen that, say, a reg with old id 5 had new id 9, any subsequent
+ * regs with old id 5 must also have new id 9 for the new state to be safe. But
+ * regs with a different old id could still have new id 9, we don't care about
+ * that.
+ * So we look through our idmap to see if this old id has been seen before. If
+ * so, we require the new id to match; otherwise, we add the id pair to the map.
+ */
+static bool check_ids(u32 old_id, u32 cur_id, struct bpf_idmap *idmap)
+{
+ struct bpf_id_pair *map = idmap->map;
+ unsigned int i;
+
+ /* either both IDs should be set or both should be zero */
+ if (!!old_id != !!cur_id)
+ return false;
+
+ if (old_id == 0) /* cur_id == 0 as well */
+ return true;
+
+ for (i = 0; i < BPF_ID_MAP_SIZE; i++) {
+ if (!map[i].old) {
+ /* Reached an empty slot; haven't seen this id before */
+ map[i].old = old_id;
+ map[i].cur = cur_id;
+ return true;
+ }
+ if (map[i].old == old_id)
+ return map[i].cur == cur_id;
+ if (map[i].cur == cur_id)
+ return false;
+ }
+ /* We ran out of idmap slots, which should be impossible */
+ WARN_ON_ONCE(1);
+ return false;
+}
+
+/* Similar to check_ids(), but allocate a unique temporary ID
+ * for 'old_id' or 'cur_id' of zero.
+ * This makes pairs like '0 vs unique ID', 'unique ID vs 0' valid.
+ */
+static bool check_scalar_ids(u32 old_id, u32 cur_id, struct bpf_idmap *idmap)
+{
+ old_id = old_id ? old_id : ++idmap->tmp_id_gen;
+ cur_id = cur_id ? cur_id : ++idmap->tmp_id_gen;
+
+ return check_ids(old_id, cur_id, idmap);
+}
+
+static void clean_func_state(struct bpf_verifier_env *env,
+ struct bpf_func_state *st)
+{
+ enum bpf_reg_liveness live;
+ int i, j;
+
+ for (i = 0; i < BPF_REG_FP; i++) {
+ live = st->regs[i].live;
+ /* liveness must not touch this register anymore */
+ st->regs[i].live |= REG_LIVE_DONE;
+ if (!(live & REG_LIVE_READ))
+ /* since the register is unused, clear its state
+ * to make further comparison simpler
+ */
+ __mark_reg_not_init(env, &st->regs[i]);
+ }
+
+ for (i = 0; i < st->allocated_stack / BPF_REG_SIZE; i++) {
+ live = st->stack[i].spilled_ptr.live;
+ /* liveness must not touch this stack slot anymore */
+ st->stack[i].spilled_ptr.live |= REG_LIVE_DONE;
+ if (!(live & REG_LIVE_READ)) {
+ __mark_reg_not_init(env, &st->stack[i].spilled_ptr);
+ for (j = 0; j < BPF_REG_SIZE; j++)
+ st->stack[i].slot_type[j] = STACK_INVALID;
+ }
+ }
+}
+
+static void clean_verifier_state(struct bpf_verifier_env *env,
+ struct bpf_verifier_state *st)
+{
+ int i;
+
+ if (st->frame[0]->regs[0].live & REG_LIVE_DONE)
+ /* all regs in this state in all frames were already marked */
+ return;
+
+ for (i = 0; i <= st->curframe; i++)
+ clean_func_state(env, st->frame[i]);
+}
+
+/* the parentage chains form a tree.
+ * the verifier states are added to state lists at given insn and
+ * pushed into state stack for future exploration.
+ * when the verifier reaches bpf_exit insn some of the verifer states
+ * stored in the state lists have their final liveness state already,
+ * but a lot of states will get revised from liveness point of view when
+ * the verifier explores other branches.
+ * Example:
+ * 1: r0 = 1
+ * 2: if r1 == 100 goto pc+1
+ * 3: r0 = 2
+ * 4: exit
+ * when the verifier reaches exit insn the register r0 in the state list of
+ * insn 2 will be seen as !REG_LIVE_READ. Then the verifier pops the other_branch
+ * of insn 2 and goes exploring further. At the insn 4 it will walk the
+ * parentage chain from insn 4 into insn 2 and will mark r0 as REG_LIVE_READ.
+ *
+ * Since the verifier pushes the branch states as it sees them while exploring
+ * the program the condition of walking the branch instruction for the second
+ * time means that all states below this branch were already explored and
+ * their final liveness marks are already propagated.
+ * Hence when the verifier completes the search of state list in is_state_visited()
+ * we can call this clean_live_states() function to mark all liveness states
+ * as REG_LIVE_DONE to indicate that 'parent' pointers of 'struct bpf_reg_state'
+ * will not be used.
+ * This function also clears the registers and stack for states that !READ
+ * to simplify state merging.
+ *
+ * Important note here that walking the same branch instruction in the callee
+ * doesn't meant that the states are DONE. The verifier has to compare
+ * the callsites
+ */
+static void clean_live_states(struct bpf_verifier_env *env, int insn,
+ struct bpf_verifier_state *cur)
+{
+ struct bpf_verifier_state_list *sl;
+
+ sl = *explored_state(env, insn);
+ while (sl) {
+ if (sl->state.branches)
+ goto next;
+ if (sl->state.insn_idx != insn ||
+ !same_callsites(&sl->state, cur))
+ goto next;
+ clean_verifier_state(env, &sl->state);
+next:
+ sl = sl->next;
+ }
+}
+
+static bool regs_exact(const struct bpf_reg_state *rold,
+ const struct bpf_reg_state *rcur,
+ struct bpf_idmap *idmap)
+{
+ return memcmp(rold, rcur, offsetof(struct bpf_reg_state, id)) == 0 &&
+ check_ids(rold->id, rcur->id, idmap) &&
+ check_ids(rold->ref_obj_id, rcur->ref_obj_id, idmap);
+}
+
+/* Returns true if (rold safe implies rcur safe) */
+static bool regsafe(struct bpf_verifier_env *env, struct bpf_reg_state *rold,
+ struct bpf_reg_state *rcur, struct bpf_idmap *idmap, bool exact)
+{
+ if (exact)
+ return regs_exact(rold, rcur, idmap);
+
+ if (!(rold->live & REG_LIVE_READ))
+ /* explored state didn't use this */
+ return true;
+ if (rold->type == NOT_INIT)
+ /* explored state can't have used this */
+ return true;
+ if (rcur->type == NOT_INIT)
+ return false;
+
+ /* Enforce that register types have to match exactly, including their
+ * modifiers (like PTR_MAYBE_NULL, MEM_RDONLY, etc), as a general
+ * rule.
+ *
+ * One can make a point that using a pointer register as unbounded
+ * SCALAR would be technically acceptable, but this could lead to
+ * pointer leaks because scalars are allowed to leak while pointers
+ * are not. We could make this safe in special cases if root is
+ * calling us, but it's probably not worth the hassle.
+ *
+ * Also, register types that are *not* MAYBE_NULL could technically be
+ * safe to use as their MAYBE_NULL variants (e.g., PTR_TO_MAP_VALUE
+ * is safe to be used as PTR_TO_MAP_VALUE_OR_NULL, provided both point
+ * to the same map).
+ * However, if the old MAYBE_NULL register then got NULL checked,
+ * doing so could have affected others with the same id, and we can't
+ * check for that because we lost the id when we converted to
+ * a non-MAYBE_NULL variant.
+ * So, as a general rule we don't allow mixing MAYBE_NULL and
+ * non-MAYBE_NULL registers as well.
+ */
+ if (rold->type != rcur->type)
+ return false;
+
+ switch (base_type(rold->type)) {
+ case SCALAR_VALUE:
+ if (env->explore_alu_limits) {
+ /* explore_alu_limits disables tnum_in() and range_within()
+ * logic and requires everything to be strict
+ */
+ return memcmp(rold, rcur, offsetof(struct bpf_reg_state, id)) == 0 &&
+ check_scalar_ids(rold->id, rcur->id, idmap);
+ }
+ if (!rold->precise)
+ return true;
+ /* Why check_ids() for scalar registers?
+ *
+ * Consider the following BPF code:
+ * 1: r6 = ... unbound scalar, ID=a ...
+ * 2: r7 = ... unbound scalar, ID=b ...
+ * 3: if (r6 > r7) goto +1
+ * 4: r6 = r7
+ * 5: if (r6 > X) goto ...
+ * 6: ... memory operation using r7 ...
+ *
+ * First verification path is [1-6]:
+ * - at (4) same bpf_reg_state::id (b) would be assigned to r6 and r7;
+ * - at (5) r6 would be marked <= X, find_equal_scalars() would also mark
+ * r7 <= X, because r6 and r7 share same id.
+ * Next verification path is [1-4, 6].
+ *
+ * Instruction (6) would be reached in two states:
+ * I. r6{.id=b}, r7{.id=b} via path 1-6;
+ * II. r6{.id=a}, r7{.id=b} via path 1-4, 6.
+ *
+ * Use check_ids() to distinguish these states.
+ * ---
+ * Also verify that new value satisfies old value range knowledge.
+ */
+ return range_within(rold, rcur) &&
+ tnum_in(rold->var_off, rcur->var_off) &&
+ check_scalar_ids(rold->id, rcur->id, idmap);
+ case PTR_TO_MAP_KEY:
+ case PTR_TO_MAP_VALUE:
+ case PTR_TO_MEM:
+ case PTR_TO_BUF:
+ case PTR_TO_TP_BUFFER:
+ /* If the new min/max/var_off satisfy the old ones and
+ * everything else matches, we are OK.
+ */
+ return memcmp(rold, rcur, offsetof(struct bpf_reg_state, var_off)) == 0 &&
+ range_within(rold, rcur) &&
+ tnum_in(rold->var_off, rcur->var_off) &&
+ check_ids(rold->id, rcur->id, idmap) &&
+ check_ids(rold->ref_obj_id, rcur->ref_obj_id, idmap);
+ case PTR_TO_PACKET_META:
+ case PTR_TO_PACKET:
+ /* We must have at least as much range as the old ptr
+ * did, so that any accesses which were safe before are
+ * still safe. This is true even if old range < old off,
+ * since someone could have accessed through (ptr - k), or
+ * even done ptr -= k in a register, to get a safe access.
+ */
+ if (rold->range > rcur->range)
+ return false;
+ /* If the offsets don't match, we can't trust our alignment;
+ * nor can we be sure that we won't fall out of range.
+ */
+ if (rold->off != rcur->off)
+ return false;
+ /* id relations must be preserved */
+ if (!check_ids(rold->id, rcur->id, idmap))
+ return false;
+ /* new val must satisfy old val knowledge */
+ return range_within(rold, rcur) &&
+ tnum_in(rold->var_off, rcur->var_off);
+ case PTR_TO_STACK:
+ /* two stack pointers are equal only if they're pointing to
+ * the same stack frame, since fp-8 in foo != fp-8 in bar
+ */
+ return regs_exact(rold, rcur, idmap) && rold->frameno == rcur->frameno;
+ default:
+ return regs_exact(rold, rcur, idmap);
+ }
+}
+
+static bool stacksafe(struct bpf_verifier_env *env, struct bpf_func_state *old,
+ struct bpf_func_state *cur, struct bpf_idmap *idmap, bool exact)
+{
+ int i, spi;
+
+ /* walk slots of the explored stack and ignore any additional
+ * slots in the current stack, since explored(safe) state
+ * didn't use them
+ */
+ for (i = 0; i < old->allocated_stack; i++) {
+ struct bpf_reg_state *old_reg, *cur_reg;
+
+ spi = i / BPF_REG_SIZE;
+
+ if (exact &&
+ old->stack[spi].slot_type[i % BPF_REG_SIZE] !=
+ cur->stack[spi].slot_type[i % BPF_REG_SIZE])
+ return false;
+
+ if (!(old->stack[spi].spilled_ptr.live & REG_LIVE_READ) && !exact) {
+ i += BPF_REG_SIZE - 1;
+ /* explored state didn't use this */
+ continue;
+ }
+
+ if (old->stack[spi].slot_type[i % BPF_REG_SIZE] == STACK_INVALID)
+ continue;
+
+ if (env->allow_uninit_stack &&
+ old->stack[spi].slot_type[i % BPF_REG_SIZE] == STACK_MISC)
+ continue;
+
+ /* explored stack has more populated slots than current stack
+ * and these slots were used
+ */
+ if (i >= cur->allocated_stack)
+ return false;
+
+ /* if old state was safe with misc data in the stack
+ * it will be safe with zero-initialized stack.
+ * The opposite is not true
+ */
+ if (old->stack[spi].slot_type[i % BPF_REG_SIZE] == STACK_MISC &&
+ cur->stack[spi].slot_type[i % BPF_REG_SIZE] == STACK_ZERO)
+ continue;
+ if (old->stack[spi].slot_type[i % BPF_REG_SIZE] !=
+ cur->stack[spi].slot_type[i % BPF_REG_SIZE])
+ /* Ex: old explored (safe) state has STACK_SPILL in
+ * this stack slot, but current has STACK_MISC ->
+ * this verifier states are not equivalent,
+ * return false to continue verification of this path
+ */
+ return false;
+ if (i % BPF_REG_SIZE != BPF_REG_SIZE - 1)
+ continue;
+ /* Both old and cur are having same slot_type */
+ switch (old->stack[spi].slot_type[BPF_REG_SIZE - 1]) {
+ case STACK_SPILL:
+ /* when explored and current stack slot are both storing
+ * spilled registers, check that stored pointers types
+ * are the same as well.
+ * Ex: explored safe path could have stored
+ * (bpf_reg_state) {.type = PTR_TO_STACK, .off = -8}
+ * but current path has stored:
+ * (bpf_reg_state) {.type = PTR_TO_STACK, .off = -16}
+ * such verifier states are not equivalent.
+ * return false to continue verification of this path
+ */
+ if (!regsafe(env, &old->stack[spi].spilled_ptr,
+ &cur->stack[spi].spilled_ptr, idmap, exact))
+ return false;
+ break;
+ case STACK_DYNPTR:
+ old_reg = &old->stack[spi].spilled_ptr;
+ cur_reg = &cur->stack[spi].spilled_ptr;
+ if (old_reg->dynptr.type != cur_reg->dynptr.type ||
+ old_reg->dynptr.first_slot != cur_reg->dynptr.first_slot ||
+ !check_ids(old_reg->ref_obj_id, cur_reg->ref_obj_id, idmap))
+ return false;
+ break;
+ case STACK_ITER:
+ old_reg = &old->stack[spi].spilled_ptr;
+ cur_reg = &cur->stack[spi].spilled_ptr;
+ /* iter.depth is not compared between states as it
+ * doesn't matter for correctness and would otherwise
+ * prevent convergence; we maintain it only to prevent
+ * infinite loop check triggering, see
+ * iter_active_depths_differ()
+ */
+ if (old_reg->iter.btf != cur_reg->iter.btf ||
+ old_reg->iter.btf_id != cur_reg->iter.btf_id ||
+ old_reg->iter.state != cur_reg->iter.state ||
+ /* ignore {old_reg,cur_reg}->iter.depth, see above */
+ !check_ids(old_reg->ref_obj_id, cur_reg->ref_obj_id, idmap))
+ return false;
+ break;
+ case STACK_MISC:
+ case STACK_ZERO:
+ case STACK_INVALID:
+ continue;
+ /* Ensure that new unhandled slot types return false by default */
+ default:
+ return false;
+ }
+ }
+ return true;
+}
+
+static bool refsafe(struct bpf_func_state *old, struct bpf_func_state *cur,
+ struct bpf_idmap *idmap)
+{
+ int i;
+
+ if (old->acquired_refs != cur->acquired_refs)
+ return false;
+
+ for (i = 0; i < old->acquired_refs; i++) {
+ if (!check_ids(old->refs[i].id, cur->refs[i].id, idmap))
+ return false;
+ }
+
+ return true;
+}
+
+/* compare two verifier states
+ *
+ * all states stored in state_list are known to be valid, since
+ * verifier reached 'bpf_exit' instruction through them
+ *
+ * this function is called when verifier exploring different branches of
+ * execution popped from the state stack. If it sees an old state that has
+ * more strict register state and more strict stack state then this execution
+ * branch doesn't need to be explored further, since verifier already
+ * concluded that more strict state leads to valid finish.
+ *
+ * Therefore two states are equivalent if register state is more conservative
+ * and explored stack state is more conservative than the current one.
+ * Example:
+ * explored current
+ * (slot1=INV slot2=MISC) == (slot1=MISC slot2=MISC)
+ * (slot1=MISC slot2=MISC) != (slot1=INV slot2=MISC)
+ *
+ * In other words if current stack state (one being explored) has more
+ * valid slots than old one that already passed validation, it means
+ * the verifier can stop exploring and conclude that current state is valid too
+ *
+ * Similarly with registers. If explored state has register type as invalid
+ * whereas register type in current state is meaningful, it means that
+ * the current state will reach 'bpf_exit' instruction safely
+ */
+static bool func_states_equal(struct bpf_verifier_env *env, struct bpf_func_state *old,
+ struct bpf_func_state *cur, bool exact)
+{
+ int i;
+
+ for (i = 0; i < MAX_BPF_REG; i++)
+ if (!regsafe(env, &old->regs[i], &cur->regs[i],
+ &env->idmap_scratch, exact))
+ return false;
+
+ if (!stacksafe(env, old, cur, &env->idmap_scratch, exact))
+ return false;
+
+ if (!refsafe(old, cur, &env->idmap_scratch))
+ return false;
+
+ return true;
+}
+
+static void reset_idmap_scratch(struct bpf_verifier_env *env)
+{
+ env->idmap_scratch.tmp_id_gen = env->id_gen;
+ memset(&env->idmap_scratch.map, 0, sizeof(env->idmap_scratch.map));
+}
+
+static bool states_equal(struct bpf_verifier_env *env,
+ struct bpf_verifier_state *old,
+ struct bpf_verifier_state *cur,
+ bool exact)
+{
+ int i;
+
+ if (old->curframe != cur->curframe)
+ return false;
+
+ reset_idmap_scratch(env);
+
+ /* Verification state from speculative execution simulation
+ * must never prune a non-speculative execution one.
+ */
+ if (old->speculative && !cur->speculative)
+ return false;
+
+ if (old->active_lock.ptr != cur->active_lock.ptr)
+ return false;
+
+ /* Old and cur active_lock's have to be either both present
+ * or both absent.
+ */
+ if (!!old->active_lock.id != !!cur->active_lock.id)
+ return false;
+
+ if (old->active_lock.id &&
+ !check_ids(old->active_lock.id, cur->active_lock.id, &env->idmap_scratch))
+ return false;
+
+ if (old->active_rcu_lock != cur->active_rcu_lock)
+ return false;
+
+ /* for states to be equal callsites have to be the same
+ * and all frame states need to be equivalent
+ */
+ for (i = 0; i <= old->curframe; i++) {
+ if (old->frame[i]->callsite != cur->frame[i]->callsite)
+ return false;
+ if (!func_states_equal(env, old->frame[i], cur->frame[i], exact))
+ return false;
+ }
+ return true;
+}
+
+/* Return 0 if no propagation happened. Return negative error code if error
+ * happened. Otherwise, return the propagated bit.
+ */
+static int propagate_liveness_reg(struct bpf_verifier_env *env,
+ struct bpf_reg_state *reg,
+ struct bpf_reg_state *parent_reg)
+{
+ u8 parent_flag = parent_reg->live & REG_LIVE_READ;
+ u8 flag = reg->live & REG_LIVE_READ;
+ int err;
+
+ /* When comes here, read flags of PARENT_REG or REG could be any of
+ * REG_LIVE_READ64, REG_LIVE_READ32, REG_LIVE_NONE. There is no need
+ * of propagation if PARENT_REG has strongest REG_LIVE_READ64.
+ */
+ if (parent_flag == REG_LIVE_READ64 ||
+ /* Or if there is no read flag from REG. */
+ !flag ||
+ /* Or if the read flag from REG is the same as PARENT_REG. */
+ parent_flag == flag)
+ return 0;
+
+ err = mark_reg_read(env, reg, parent_reg, flag);
+ if (err)
+ return err;
+
+ return flag;
+}
+
+/* A write screens off any subsequent reads; but write marks come from the
+ * straight-line code between a state and its parent. When we arrive at an
+ * equivalent state (jump target or such) we didn't arrive by the straight-line
+ * code, so read marks in the state must propagate to the parent regardless
+ * of the state's write marks. That's what 'parent == state->parent' comparison
+ * in mark_reg_read() is for.
+ */
+static int propagate_liveness(struct bpf_verifier_env *env,
+ const struct bpf_verifier_state *vstate,
+ struct bpf_verifier_state *vparent)
+{
+ struct bpf_reg_state *state_reg, *parent_reg;
+ struct bpf_func_state *state, *parent;
+ int i, frame, err = 0;
+
+ if (vparent->curframe != vstate->curframe) {
+ WARN(1, "propagate_live: parent frame %d current frame %d\n",
+ vparent->curframe, vstate->curframe);
+ return -EFAULT;
+ }
+ /* Propagate read liveness of registers... */
+ BUILD_BUG_ON(BPF_REG_FP + 1 != MAX_BPF_REG);
+ for (frame = 0; frame <= vstate->curframe; frame++) {
+ parent = vparent->frame[frame];
+ state = vstate->frame[frame];
+ parent_reg = parent->regs;
+ state_reg = state->regs;
+ /* We don't need to worry about FP liveness, it's read-only */
+ for (i = frame < vstate->curframe ? BPF_REG_6 : 0; i < BPF_REG_FP; i++) {
+ err = propagate_liveness_reg(env, &state_reg[i],
+ &parent_reg[i]);
+ if (err < 0)
+ return err;
+ if (err == REG_LIVE_READ64)
+ mark_insn_zext(env, &parent_reg[i]);
+ }
+
+ /* Propagate stack slots. */
+ for (i = 0; i < state->allocated_stack / BPF_REG_SIZE &&
+ i < parent->allocated_stack / BPF_REG_SIZE; i++) {
+ parent_reg = &parent->stack[i].spilled_ptr;
+ state_reg = &state->stack[i].spilled_ptr;
+ err = propagate_liveness_reg(env, state_reg,
+ parent_reg);
+ if (err < 0)
+ return err;
+ }
+ }
+ return 0;
+}
+
+/* find precise scalars in the previous equivalent state and
+ * propagate them into the current state
+ */
+static int propagate_precision(struct bpf_verifier_env *env,
+ const struct bpf_verifier_state *old)
+{
+ struct bpf_reg_state *state_reg;
+ struct bpf_func_state *state;
+ int i, err = 0, fr;
+ bool first;
+
+ for (fr = old->curframe; fr >= 0; fr--) {
+ state = old->frame[fr];
+ state_reg = state->regs;
+ first = true;
+ for (i = 0; i < BPF_REG_FP; i++, state_reg++) {
+ if (state_reg->type != SCALAR_VALUE ||
+ !state_reg->precise ||
+ !(state_reg->live & REG_LIVE_READ))
+ continue;
+ if (env->log.level & BPF_LOG_LEVEL2) {
+ if (first)
+ verbose(env, "frame %d: propagating r%d", fr, i);
+ else
+ verbose(env, ",r%d", i);
+ }
+ bt_set_frame_reg(&env->bt, fr, i);
+ first = false;
+ }
+
+ for (i = 0; i < state->allocated_stack / BPF_REG_SIZE; i++) {
+ if (!is_spilled_reg(&state->stack[i]))
+ continue;
+ state_reg = &state->stack[i].spilled_ptr;
+ if (state_reg->type != SCALAR_VALUE ||
+ !state_reg->precise ||
+ !(state_reg->live & REG_LIVE_READ))
+ continue;
+ if (env->log.level & BPF_LOG_LEVEL2) {
+ if (first)
+ verbose(env, "frame %d: propagating fp%d",
+ fr, (-i - 1) * BPF_REG_SIZE);
+ else
+ verbose(env, ",fp%d", (-i - 1) * BPF_REG_SIZE);
+ }
+ bt_set_frame_slot(&env->bt, fr, i);
+ first = false;
+ }
+ if (!first)
+ verbose(env, "\n");
+ }
+
+ err = mark_chain_precision_batch(env);
+ if (err < 0)
+ return err;
+
+ return 0;
+}
+
+static bool states_maybe_looping(struct bpf_verifier_state *old,
+ struct bpf_verifier_state *cur)
+{
+ struct bpf_func_state *fold, *fcur;
+ int i, fr = cur->curframe;
+
+ if (old->curframe != fr)
+ return false;
+
+ fold = old->frame[fr];
+ fcur = cur->frame[fr];
+ for (i = 0; i < MAX_BPF_REG; i++)
+ if (memcmp(&fold->regs[i], &fcur->regs[i],
+ offsetof(struct bpf_reg_state, parent)))
+ return false;
+ return true;
+}
+
+static bool is_iter_next_insn(struct bpf_verifier_env *env, int insn_idx)
+{
+ return env->insn_aux_data[insn_idx].is_iter_next;
+}
+
+/* is_state_visited() handles iter_next() (see process_iter_next_call() for
+ * terminology) calls specially: as opposed to bounded BPF loops, it *expects*
+ * states to match, which otherwise would look like an infinite loop. So while
+ * iter_next() calls are taken care of, we still need to be careful and
+ * prevent erroneous and too eager declaration of "ininite loop", when
+ * iterators are involved.
+ *
+ * Here's a situation in pseudo-BPF assembly form:
+ *
+ * 0: again: ; set up iter_next() call args
+ * 1: r1 = &it ; <CHECKPOINT HERE>
+ * 2: call bpf_iter_num_next ; this is iter_next() call
+ * 3: if r0 == 0 goto done
+ * 4: ... something useful here ...
+ * 5: goto again ; another iteration
+ * 6: done:
+ * 7: r1 = &it
+ * 8: call bpf_iter_num_destroy ; clean up iter state
+ * 9: exit
+ *
+ * This is a typical loop. Let's assume that we have a prune point at 1:,
+ * before we get to `call bpf_iter_num_next` (e.g., because of that `goto
+ * again`, assuming other heuristics don't get in a way).
+ *
+ * When we first time come to 1:, let's say we have some state X. We proceed
+ * to 2:, fork states, enqueue ACTIVE, validate NULL case successfully, exit.
+ * Now we come back to validate that forked ACTIVE state. We proceed through
+ * 3-5, come to goto, jump to 1:. Let's assume our state didn't change, so we
+ * are converging. But the problem is that we don't know that yet, as this
+ * convergence has to happen at iter_next() call site only. So if nothing is
+ * done, at 1: verifier will use bounded loop logic and declare infinite
+ * looping (and would be *technically* correct, if not for iterator's
+ * "eventual sticky NULL" contract, see process_iter_next_call()). But we
+ * don't want that. So what we do in process_iter_next_call() when we go on
+ * another ACTIVE iteration, we bump slot->iter.depth, to mark that it's
+ * a different iteration. So when we suspect an infinite loop, we additionally
+ * check if any of the *ACTIVE* iterator states depths differ. If yes, we
+ * pretend we are not looping and wait for next iter_next() call.
+ *
+ * This only applies to ACTIVE state. In DRAINED state we don't expect to
+ * loop, because that would actually mean infinite loop, as DRAINED state is
+ * "sticky", and so we'll keep returning into the same instruction with the
+ * same state (at least in one of possible code paths).
+ *
+ * This approach allows to keep infinite loop heuristic even in the face of
+ * active iterator. E.g., C snippet below is and will be detected as
+ * inifintely looping:
+ *
+ * struct bpf_iter_num it;
+ * int *p, x;
+ *
+ * bpf_iter_num_new(&it, 0, 10);
+ * while ((p = bpf_iter_num_next(&t))) {
+ * x = p;
+ * while (x--) {} // <<-- infinite loop here
+ * }
+ *
+ */
+static bool iter_active_depths_differ(struct bpf_verifier_state *old, struct bpf_verifier_state *cur)
+{
+ struct bpf_reg_state *slot, *cur_slot;
+ struct bpf_func_state *state;
+ int i, fr;
+
+ for (fr = old->curframe; fr >= 0; fr--) {
+ state = old->frame[fr];
+ for (i = 0; i < state->allocated_stack / BPF_REG_SIZE; i++) {
+ if (state->stack[i].slot_type[0] != STACK_ITER)
+ continue;
+
+ slot = &state->stack[i].spilled_ptr;
+ if (slot->iter.state != BPF_ITER_STATE_ACTIVE)
+ continue;
+
+ cur_slot = &cur->frame[fr]->stack[i].spilled_ptr;
+ if (cur_slot->iter.depth != slot->iter.depth)
+ return true;
+ }
+ }
+ return false;
+}
+
+static int is_state_visited(struct bpf_verifier_env *env, int insn_idx)
+{
+ struct bpf_verifier_state_list *new_sl;
+ struct bpf_verifier_state_list *sl, **pprev;
+ struct bpf_verifier_state *cur = env->cur_state, *new, *loop_entry;
+ int i, j, n, err, states_cnt = 0;
+ bool force_new_state = env->test_state_freq || is_force_checkpoint(env, insn_idx);
+ bool add_new_state = force_new_state;
+ bool force_exact;
+
+ /* bpf progs typically have pruning point every 4 instructions
+ * http://vger.kernel.org/bpfconf2019.html#session-1
+ * Do not add new state for future pruning if the verifier hasn't seen
+ * at least 2 jumps and at least 8 instructions.
+ * This heuristics helps decrease 'total_states' and 'peak_states' metric.
+ * In tests that amounts to up to 50% reduction into total verifier
+ * memory consumption and 20% verifier time speedup.
+ */
+ if (env->jmps_processed - env->prev_jmps_processed >= 2 &&
+ env->insn_processed - env->prev_insn_processed >= 8)
+ add_new_state = true;
+
+ pprev = explored_state(env, insn_idx);
+ sl = *pprev;
+
+ clean_live_states(env, insn_idx, cur);
+
+ while (sl) {
+ states_cnt++;
+ if (sl->state.insn_idx != insn_idx)
+ goto next;
+
+ if (sl->state.branches) {
+ struct bpf_func_state *frame = sl->state.frame[sl->state.curframe];
+
+ if (frame->in_async_callback_fn &&
+ frame->async_entry_cnt != cur->frame[cur->curframe]->async_entry_cnt) {
+ /* Different async_entry_cnt means that the verifier is
+ * processing another entry into async callback.
+ * Seeing the same state is not an indication of infinite
+ * loop or infinite recursion.
+ * But finding the same state doesn't mean that it's safe
+ * to stop processing the current state. The previous state
+ * hasn't yet reached bpf_exit, since state.branches > 0.
+ * Checking in_async_callback_fn alone is not enough either.
+ * Since the verifier still needs to catch infinite loops
+ * inside async callbacks.
+ */
+ goto skip_inf_loop_check;
+ }
+ /* BPF open-coded iterators loop detection is special.
+ * states_maybe_looping() logic is too simplistic in detecting
+ * states that *might* be equivalent, because it doesn't know
+ * about ID remapping, so don't even perform it.
+ * See process_iter_next_call() and iter_active_depths_differ()
+ * for overview of the logic. When current and one of parent
+ * states are detected as equivalent, it's a good thing: we prove
+ * convergence and can stop simulating further iterations.
+ * It's safe to assume that iterator loop will finish, taking into
+ * account iter_next() contract of eventually returning
+ * sticky NULL result.
+ *
+ * Note, that states have to be compared exactly in this case because
+ * read and precision marks might not be finalized inside the loop.
+ * E.g. as in the program below:
+ *
+ * 1. r7 = -16
+ * 2. r6 = bpf_get_prandom_u32()
+ * 3. while (bpf_iter_num_next(&fp[-8])) {
+ * 4. if (r6 != 42) {
+ * 5. r7 = -32
+ * 6. r6 = bpf_get_prandom_u32()
+ * 7. continue
+ * 8. }
+ * 9. r0 = r10
+ * 10. r0 += r7
+ * 11. r8 = *(u64 *)(r0 + 0)
+ * 12. r6 = bpf_get_prandom_u32()
+ * 13. }
+ *
+ * Here verifier would first visit path 1-3, create a checkpoint at 3
+ * with r7=-16, continue to 4-7,3. Existing checkpoint at 3 does
+ * not have read or precision mark for r7 yet, thus inexact states
+ * comparison would discard current state with r7=-32
+ * => unsafe memory access at 11 would not be caught.
+ */
+ if (is_iter_next_insn(env, insn_idx)) {
+ if (states_equal(env, &sl->state, cur, true)) {
+ struct bpf_func_state *cur_frame;
+ struct bpf_reg_state *iter_state, *iter_reg;
+ int spi;
+
+ cur_frame = cur->frame[cur->curframe];
+ /* btf_check_iter_kfuncs() enforces that
+ * iter state pointer is always the first arg
+ */
+ iter_reg = &cur_frame->regs[BPF_REG_1];
+ /* current state is valid due to states_equal(),
+ * so we can assume valid iter and reg state,
+ * no need for extra (re-)validations
+ */
+ spi = __get_spi(iter_reg->off + iter_reg->var_off.value);
+ iter_state = &func(env, iter_reg)->stack[spi].spilled_ptr;
+ if (iter_state->iter.state == BPF_ITER_STATE_ACTIVE) {
+ update_loop_entry(cur, &sl->state);
+ goto hit;
+ }
+ }
+ goto skip_inf_loop_check;
+ }
+ if (calls_callback(env, insn_idx)) {
+ if (states_equal(env, &sl->state, cur, true))
+ goto hit;
+ goto skip_inf_loop_check;
+ }
+ /* attempt to detect infinite loop to avoid unnecessary doomed work */
+ if (states_maybe_looping(&sl->state, cur) &&
+ states_equal(env, &sl->state, cur, false) &&
+ !iter_active_depths_differ(&sl->state, cur) &&
+ sl->state.callback_unroll_depth == cur->callback_unroll_depth) {
+ verbose_linfo(env, insn_idx, "; ");
+ verbose(env, "infinite loop detected at insn %d\n", insn_idx);
+ verbose(env, "cur state:");
+ print_verifier_state(env, cur->frame[cur->curframe], true);
+ verbose(env, "old state:");
+ print_verifier_state(env, sl->state.frame[cur->curframe], true);
+ return -EINVAL;
+ }
+ /* if the verifier is processing a loop, avoid adding new state
+ * too often, since different loop iterations have distinct
+ * states and may not help future pruning.
+ * This threshold shouldn't be too low to make sure that
+ * a loop with large bound will be rejected quickly.
+ * The most abusive loop will be:
+ * r1 += 1
+ * if r1 < 1000000 goto pc-2
+ * 1M insn_procssed limit / 100 == 10k peak states.
+ * This threshold shouldn't be too high either, since states
+ * at the end of the loop are likely to be useful in pruning.
+ */
+skip_inf_loop_check:
+ if (!force_new_state &&
+ env->jmps_processed - env->prev_jmps_processed < 20 &&
+ env->insn_processed - env->prev_insn_processed < 100)
+ add_new_state = false;
+ goto miss;
+ }
+ /* If sl->state is a part of a loop and this loop's entry is a part of
+ * current verification path then states have to be compared exactly.
+ * 'force_exact' is needed to catch the following case:
+ *
+ * initial Here state 'succ' was processed first,
+ * | it was eventually tracked to produce a
+ * V state identical to 'hdr'.
+ * .---------> hdr All branches from 'succ' had been explored
+ * | | and thus 'succ' has its .branches == 0.
+ * | V
+ * | .------... Suppose states 'cur' and 'succ' correspond
+ * | | | to the same instruction + callsites.
+ * | V V In such case it is necessary to check
+ * | ... ... if 'succ' and 'cur' are states_equal().
+ * | | | If 'succ' and 'cur' are a part of the
+ * | V V same loop exact flag has to be set.
+ * | succ <- cur To check if that is the case, verify
+ * | | if loop entry of 'succ' is in current
+ * | V DFS path.
+ * | ...
+ * | |
+ * '----'
+ *
+ * Additional details are in the comment before get_loop_entry().
+ */
+ loop_entry = get_loop_entry(&sl->state);
+ force_exact = loop_entry && loop_entry->branches > 0;
+ if (states_equal(env, &sl->state, cur, force_exact)) {
+ if (force_exact)
+ update_loop_entry(cur, loop_entry);
+hit:
+ sl->hit_cnt++;
+ /* reached equivalent register/stack state,
+ * prune the search.
+ * Registers read by the continuation are read by us.
+ * If we have any write marks in env->cur_state, they
+ * will prevent corresponding reads in the continuation
+ * from reaching our parent (an explored_state). Our
+ * own state will get the read marks recorded, but
+ * they'll be immediately forgotten as we're pruning
+ * this state and will pop a new one.
+ */
+ err = propagate_liveness(env, &sl->state, cur);
+
+ /* if previous state reached the exit with precision and
+ * current state is equivalent to it (except precsion marks)
+ * the precision needs to be propagated back in
+ * the current state.
+ */
+ err = err ? : push_jmp_history(env, cur);
+ err = err ? : propagate_precision(env, &sl->state);
+ if (err)
+ return err;
+ return 1;
+ }
+miss:
+ /* when new state is not going to be added do not increase miss count.
+ * Otherwise several loop iterations will remove the state
+ * recorded earlier. The goal of these heuristics is to have
+ * states from some iterations of the loop (some in the beginning
+ * and some at the end) to help pruning.
+ */
+ if (add_new_state)
+ sl->miss_cnt++;
+ /* heuristic to determine whether this state is beneficial
+ * to keep checking from state equivalence point of view.
+ * Higher numbers increase max_states_per_insn and verification time,
+ * but do not meaningfully decrease insn_processed.
+ * 'n' controls how many times state could miss before eviction.
+ * Use bigger 'n' for checkpoints because evicting checkpoint states
+ * too early would hinder iterator convergence.
+ */
+ n = is_force_checkpoint(env, insn_idx) && sl->state.branches > 0 ? 64 : 3;
+ if (sl->miss_cnt > sl->hit_cnt * n + n) {
+ /* the state is unlikely to be useful. Remove it to
+ * speed up verification
+ */
+ *pprev = sl->next;
+ if (sl->state.frame[0]->regs[0].live & REG_LIVE_DONE &&
+ !sl->state.used_as_loop_entry) {
+ u32 br = sl->state.branches;
+
+ WARN_ONCE(br,
+ "BUG live_done but branches_to_explore %d\n",
+ br);
+ free_verifier_state(&sl->state, false);
+ kfree(sl);
+ env->peak_states--;
+ } else {
+ /* cannot free this state, since parentage chain may
+ * walk it later. Add it for free_list instead to
+ * be freed at the end of verification
+ */
+ sl->next = env->free_list;
+ env->free_list = sl;
+ }
+ sl = *pprev;
+ continue;
+ }
+next:
+ pprev = &sl->next;
+ sl = *pprev;
+ }
+
+ if (env->max_states_per_insn < states_cnt)
+ env->max_states_per_insn = states_cnt;
+
+ if (!env->bpf_capable && states_cnt > BPF_COMPLEXITY_LIMIT_STATES)
+ return 0;
+
+ if (!add_new_state)
+ return 0;
+
+ /* There were no equivalent states, remember the current one.
+ * Technically the current state is not proven to be safe yet,
+ * but it will either reach outer most bpf_exit (which means it's safe)
+ * or it will be rejected. When there are no loops the verifier won't be
+ * seeing this tuple (frame[0].callsite, frame[1].callsite, .. insn_idx)
+ * again on the way to bpf_exit.
+ * When looping the sl->state.branches will be > 0 and this state
+ * will not be considered for equivalence until branches == 0.
+ */
+ new_sl = kzalloc(sizeof(struct bpf_verifier_state_list), GFP_KERNEL);
+ if (!new_sl)
+ return -ENOMEM;
+ env->total_states++;
+ env->peak_states++;
+ env->prev_jmps_processed = env->jmps_processed;
+ env->prev_insn_processed = env->insn_processed;
+
+ /* forget precise markings we inherited, see __mark_chain_precision */
+ if (env->bpf_capable)
+ mark_all_scalars_imprecise(env, cur);
+
+ /* add new state to the head of linked list */
+ new = &new_sl->state;
+ err = copy_verifier_state(new, cur);
+ if (err) {
+ free_verifier_state(new, false);
+ kfree(new_sl);
+ return err;
+ }
+ new->insn_idx = insn_idx;
+ WARN_ONCE(new->branches != 1,
+ "BUG is_state_visited:branches_to_explore=%d insn %d\n", new->branches, insn_idx);
+
+ cur->parent = new;
+ cur->first_insn_idx = insn_idx;
+ cur->dfs_depth = new->dfs_depth + 1;
+ clear_jmp_history(cur);
+ new_sl->next = *explored_state(env, insn_idx);
+ *explored_state(env, insn_idx) = new_sl;
+ /* connect new state to parentage chain. Current frame needs all
+ * registers connected. Only r6 - r9 of the callers are alive (pushed
+ * to the stack implicitly by JITs) so in callers' frames connect just
+ * r6 - r9 as an optimization. Callers will have r1 - r5 connected to
+ * the state of the call instruction (with WRITTEN set), and r0 comes
+ * from callee with its full parentage chain, anyway.
+ */
+ /* clear write marks in current state: the writes we did are not writes
+ * our child did, so they don't screen off its reads from us.
+ * (There are no read marks in current state, because reads always mark
+ * their parent and current state never has children yet. Only
+ * explored_states can get read marks.)
+ */
+ for (j = 0; j <= cur->curframe; j++) {
+ for (i = j < cur->curframe ? BPF_REG_6 : 0; i < BPF_REG_FP; i++)
+ cur->frame[j]->regs[i].parent = &new->frame[j]->regs[i];
+ for (i = 0; i < BPF_REG_FP; i++)
+ cur->frame[j]->regs[i].live = REG_LIVE_NONE;
+ }
+
+ /* all stack frames are accessible from callee, clear them all */
+ for (j = 0; j <= cur->curframe; j++) {
+ struct bpf_func_state *frame = cur->frame[j];
+ struct bpf_func_state *newframe = new->frame[j];
+
+ for (i = 0; i < frame->allocated_stack / BPF_REG_SIZE; i++) {
+ frame->stack[i].spilled_ptr.live = REG_LIVE_NONE;
+ frame->stack[i].spilled_ptr.parent =
+ &newframe->stack[i].spilled_ptr;
+ }
+ }
+ return 0;
+}
+
+/* Return true if it's OK to have the same insn return a different type. */
+static bool reg_type_mismatch_ok(enum bpf_reg_type type)
+{
+ switch (base_type(type)) {
+ case PTR_TO_CTX:
+ case PTR_TO_SOCKET:
+ case PTR_TO_SOCK_COMMON:
+ case PTR_TO_TCP_SOCK:
+ case PTR_TO_XDP_SOCK:
+ case PTR_TO_BTF_ID:
+ return false;
+ default:
+ return true;
+ }
+}
+
+/* If an instruction was previously used with particular pointer types, then we
+ * need to be careful to avoid cases such as the below, where it may be ok
+ * for one branch accessing the pointer, but not ok for the other branch:
+ *
+ * R1 = sock_ptr
+ * goto X;
+ * ...
+ * R1 = some_other_valid_ptr;
+ * goto X;
+ * ...
+ * R2 = *(u32 *)(R1 + 0);
+ */
+static bool reg_type_mismatch(enum bpf_reg_type src, enum bpf_reg_type prev)
+{
+ return src != prev && (!reg_type_mismatch_ok(src) ||
+ !reg_type_mismatch_ok(prev));
+}
+
+static int save_aux_ptr_type(struct bpf_verifier_env *env, enum bpf_reg_type type,
+ bool allow_trust_missmatch)
+{
+ enum bpf_reg_type *prev_type = &env->insn_aux_data[env->insn_idx].ptr_type;
+
+ if (*prev_type == NOT_INIT) {
+ /* Saw a valid insn
+ * dst_reg = *(u32 *)(src_reg + off)
+ * save type to validate intersecting paths
+ */
+ *prev_type = type;
+ } else if (reg_type_mismatch(type, *prev_type)) {
+ /* Abuser program is trying to use the same insn
+ * dst_reg = *(u32*) (src_reg + off)
+ * with different pointer types:
+ * src_reg == ctx in one branch and
+ * src_reg == stack|map in some other branch.
+ * Reject it.
+ */
+ if (allow_trust_missmatch &&
+ base_type(type) == PTR_TO_BTF_ID &&
+ base_type(*prev_type) == PTR_TO_BTF_ID) {
+ /*
+ * Have to support a use case when one path through
+ * the program yields TRUSTED pointer while another
+ * is UNTRUSTED. Fallback to UNTRUSTED to generate
+ * BPF_PROBE_MEM/BPF_PROBE_MEMSX.
+ */
+ *prev_type = PTR_TO_BTF_ID | PTR_UNTRUSTED;
+ } else {
+ verbose(env, "same insn cannot be used with different pointers\n");
+ return -EINVAL;
+ }
+ }
+
+ return 0;
+}
+
+static int do_check(struct bpf_verifier_env *env)
+{
+ bool pop_log = !(env->log.level & BPF_LOG_LEVEL2);
+ struct bpf_verifier_state *state = env->cur_state;
+ struct bpf_insn *insns = env->prog->insnsi;
+ struct bpf_reg_state *regs;
+ int insn_cnt = env->prog->len;
+ bool do_print_state = false;
+ int prev_insn_idx = -1;
+
+ for (;;) {
+ struct bpf_insn *insn;
+ u8 class;
+ int err;
+
+ env->prev_insn_idx = prev_insn_idx;
+ if (env->insn_idx >= insn_cnt) {
+ verbose(env, "invalid insn idx %d insn_cnt %d\n",
+ env->insn_idx, insn_cnt);
+ return -EFAULT;
+ }
+
+ insn = &insns[env->insn_idx];
+ class = BPF_CLASS(insn->code);
+
+ if (++env->insn_processed > BPF_COMPLEXITY_LIMIT_INSNS) {
+ verbose(env,
+ "BPF program is too large. Processed %d insn\n",
+ env->insn_processed);
+ return -E2BIG;
+ }
+
+ state->last_insn_idx = env->prev_insn_idx;
+
+ if (is_prune_point(env, env->insn_idx)) {
+ err = is_state_visited(env, env->insn_idx);
+ if (err < 0)
+ return err;
+ if (err == 1) {
+ /* found equivalent state, can prune the search */
+ if (env->log.level & BPF_LOG_LEVEL) {
+ if (do_print_state)
+ verbose(env, "\nfrom %d to %d%s: safe\n",
+ env->prev_insn_idx, env->insn_idx,
+ env->cur_state->speculative ?
+ " (speculative execution)" : "");
+ else
+ verbose(env, "%d: safe\n", env->insn_idx);
+ }
+ goto process_bpf_exit;
+ }
+ }
+
+ if (is_jmp_point(env, env->insn_idx)) {
+ err = push_jmp_history(env, state);
+ if (err)
+ return err;
+ }
+
+ if (signal_pending(current))
+ return -EAGAIN;
+
+ if (need_resched())
+ cond_resched();
+
+ if (env->log.level & BPF_LOG_LEVEL2 && do_print_state) {
+ verbose(env, "\nfrom %d to %d%s:",
+ env->prev_insn_idx, env->insn_idx,
+ env->cur_state->speculative ?
+ " (speculative execution)" : "");
+ print_verifier_state(env, state->frame[state->curframe], true);
+ do_print_state = false;
+ }
+
+ if (env->log.level & BPF_LOG_LEVEL) {
+ const struct bpf_insn_cbs cbs = {
+ .cb_call = disasm_kfunc_name,
+ .cb_print = verbose,
+ .private_data = env,
+ };
+
+ if (verifier_state_scratched(env))
+ print_insn_state(env, state->frame[state->curframe]);
+
+ verbose_linfo(env, env->insn_idx, "; ");
+ env->prev_log_pos = env->log.end_pos;
+ verbose(env, "%d: ", env->insn_idx);
+ print_bpf_insn(&cbs, insn, env->allow_ptr_leaks);
+ env->prev_insn_print_pos = env->log.end_pos - env->prev_log_pos;
+ env->prev_log_pos = env->log.end_pos;
+ }
+
+ if (bpf_prog_is_offloaded(env->prog->aux)) {
+ err = bpf_prog_offload_verify_insn(env, env->insn_idx,
+ env->prev_insn_idx);
+ if (err)
+ return err;
+ }
+
+ regs = cur_regs(env);
+ sanitize_mark_insn_seen(env);
+ prev_insn_idx = env->insn_idx;
+
+ if (class == BPF_ALU || class == BPF_ALU64) {
+ err = check_alu_op(env, insn);
+ if (err)
+ return err;
+
+ } else if (class == BPF_LDX) {
+ enum bpf_reg_type src_reg_type;
+
+ /* check for reserved fields is already done */
+
+ /* check src operand */
+ err = check_reg_arg(env, insn->src_reg, SRC_OP);
+ if (err)
+ return err;
+
+ err = check_reg_arg(env, insn->dst_reg, DST_OP_NO_MARK);
+ if (err)
+ return err;
+
+ src_reg_type = regs[insn->src_reg].type;
+
+ /* check that memory (src_reg + off) is readable,
+ * the state of dst_reg will be updated by this func
+ */
+ err = check_mem_access(env, env->insn_idx, insn->src_reg,
+ insn->off, BPF_SIZE(insn->code),
+ BPF_READ, insn->dst_reg, false,
+ BPF_MODE(insn->code) == BPF_MEMSX);
+ if (err)
+ return err;
+
+ err = save_aux_ptr_type(env, src_reg_type, true);
+ if (err)
+ return err;
+ } else if (class == BPF_STX) {
+ enum bpf_reg_type dst_reg_type;
+
+ if (BPF_MODE(insn->code) == BPF_ATOMIC) {
+ err = check_atomic(env, env->insn_idx, insn);
+ if (err)
+ return err;
+ env->insn_idx++;
+ continue;
+ }
+
+ if (BPF_MODE(insn->code) != BPF_MEM || insn->imm != 0) {
+ verbose(env, "BPF_STX uses reserved fields\n");
+ return -EINVAL;
+ }
+
+ /* check src1 operand */
+ err = check_reg_arg(env, insn->src_reg, SRC_OP);
+ if (err)
+ return err;
+ /* check src2 operand */
+ err = check_reg_arg(env, insn->dst_reg, SRC_OP);
+ if (err)
+ return err;
+
+ dst_reg_type = regs[insn->dst_reg].type;
+
+ /* check that memory (dst_reg + off) is writeable */
+ err = check_mem_access(env, env->insn_idx, insn->dst_reg,
+ insn->off, BPF_SIZE(insn->code),
+ BPF_WRITE, insn->src_reg, false, false);
+ if (err)
+ return err;
+
+ err = save_aux_ptr_type(env, dst_reg_type, false);
+ if (err)
+ return err;
+ } else if (class == BPF_ST) {
+ enum bpf_reg_type dst_reg_type;
+
+ if (BPF_MODE(insn->code) != BPF_MEM ||
+ insn->src_reg != BPF_REG_0) {
+ verbose(env, "BPF_ST uses reserved fields\n");
+ return -EINVAL;
+ }
+ /* check src operand */
+ err = check_reg_arg(env, insn->dst_reg, SRC_OP);
+ if (err)
+ return err;
+
+ dst_reg_type = regs[insn->dst_reg].type;
+
+ /* check that memory (dst_reg + off) is writeable */
+ err = check_mem_access(env, env->insn_idx, insn->dst_reg,
+ insn->off, BPF_SIZE(insn->code),
+ BPF_WRITE, -1, false, false);
+ if (err)
+ return err;
+
+ err = save_aux_ptr_type(env, dst_reg_type, false);
+ if (err)
+ return err;
+ } else if (class == BPF_JMP || class == BPF_JMP32) {
+ u8 opcode = BPF_OP(insn->code);
+
+ env->jmps_processed++;
+ if (opcode == BPF_CALL) {
+ if (BPF_SRC(insn->code) != BPF_K ||
+ (insn->src_reg != BPF_PSEUDO_KFUNC_CALL
+ && insn->off != 0) ||
+ (insn->src_reg != BPF_REG_0 &&
+ insn->src_reg != BPF_PSEUDO_CALL &&
+ insn->src_reg != BPF_PSEUDO_KFUNC_CALL) ||
+ insn->dst_reg != BPF_REG_0 ||
+ class == BPF_JMP32) {
+ verbose(env, "BPF_CALL uses reserved fields\n");
+ return -EINVAL;
+ }
+
+ if (env->cur_state->active_lock.ptr) {
+ if ((insn->src_reg == BPF_REG_0 && insn->imm != BPF_FUNC_spin_unlock) ||
+ (insn->src_reg == BPF_PSEUDO_CALL) ||
+ (insn->src_reg == BPF_PSEUDO_KFUNC_CALL &&
+ (insn->off != 0 || !is_bpf_graph_api_kfunc(insn->imm)))) {
+ verbose(env, "function calls are not allowed while holding a lock\n");
+ return -EINVAL;
+ }
+ }
+ if (insn->src_reg == BPF_PSEUDO_CALL)
+ err = check_func_call(env, insn, &env->insn_idx);
+ else if (insn->src_reg == BPF_PSEUDO_KFUNC_CALL)
+ err = check_kfunc_call(env, insn, &env->insn_idx);
+ else
+ err = check_helper_call(env, insn, &env->insn_idx);
+ if (err)
+ return err;
+
+ mark_reg_scratched(env, BPF_REG_0);
+ } else if (opcode == BPF_JA) {
+ if (BPF_SRC(insn->code) != BPF_K ||
+ insn->src_reg != BPF_REG_0 ||
+ insn->dst_reg != BPF_REG_0 ||
+ (class == BPF_JMP && insn->imm != 0) ||
+ (class == BPF_JMP32 && insn->off != 0)) {
+ verbose(env, "BPF_JA uses reserved fields\n");
+ return -EINVAL;
+ }
+
+ if (class == BPF_JMP)
+ env->insn_idx += insn->off + 1;
+ else
+ env->insn_idx += insn->imm + 1;
+ continue;
+
+ } else if (opcode == BPF_EXIT) {
+ if (BPF_SRC(insn->code) != BPF_K ||
+ insn->imm != 0 ||
+ insn->src_reg != BPF_REG_0 ||
+ insn->dst_reg != BPF_REG_0 ||
+ class == BPF_JMP32) {
+ verbose(env, "BPF_EXIT uses reserved fields\n");
+ return -EINVAL;
+ }
+
+ if (env->cur_state->active_lock.ptr &&
+ !in_rbtree_lock_required_cb(env)) {
+ verbose(env, "bpf_spin_unlock is missing\n");
+ return -EINVAL;
+ }
+
+ if (env->cur_state->active_rcu_lock &&
+ !in_rbtree_lock_required_cb(env)) {
+ verbose(env, "bpf_rcu_read_unlock is missing\n");
+ return -EINVAL;
+ }
+
+ /* We must do check_reference_leak here before
+ * prepare_func_exit to handle the case when
+ * state->curframe > 0, it may be a callback
+ * function, for which reference_state must
+ * match caller reference state when it exits.
+ */
+ err = check_reference_leak(env);
+ if (err)
+ return err;
+
+ if (state->curframe) {
+ /* exit from nested function */
+ err = prepare_func_exit(env, &env->insn_idx);
+ if (err)
+ return err;
+ do_print_state = true;
+ continue;
+ }
+
+ err = check_return_code(env);
+ if (err)
+ return err;
+process_bpf_exit:
+ mark_verifier_state_scratched(env);
+ update_branch_counts(env, env->cur_state);
+ err = pop_stack(env, &prev_insn_idx,
+ &env->insn_idx, pop_log);
+ if (err < 0) {
+ if (err != -ENOENT)
+ return err;
+ break;
+ } else {
+ do_print_state = true;
+ continue;
+ }
+ } else {
+ err = check_cond_jmp_op(env, insn, &env->insn_idx);
+ if (err)
+ return err;
+ }
+ } else if (class == BPF_LD) {
+ u8 mode = BPF_MODE(insn->code);
+
+ if (mode == BPF_ABS || mode == BPF_IND) {
+ err = check_ld_abs(env, insn);
+ if (err)
+ return err;
+
+ } else if (mode == BPF_IMM) {
+ err = check_ld_imm(env, insn);
+ if (err)
+ return err;
+
+ env->insn_idx++;
+ sanitize_mark_insn_seen(env);
+ } else {
+ verbose(env, "invalid BPF_LD mode\n");
+ return -EINVAL;
+ }
+ } else {
+ verbose(env, "unknown insn class %d\n", class);
+ return -EINVAL;
+ }
+
+ env->insn_idx++;
+ }
+
+ return 0;
+}
+
+static int find_btf_percpu_datasec(struct btf *btf)
+{
+ const struct btf_type *t;
+ const char *tname;
+ int i, n;
+
+ /*
+ * Both vmlinux and module each have their own ".data..percpu"
+ * DATASECs in BTF. So for module's case, we need to skip vmlinux BTF
+ * types to look at only module's own BTF types.
+ */
+ n = btf_nr_types(btf);
+ if (btf_is_module(btf))
+ i = btf_nr_types(btf_vmlinux);
+ else
+ i = 1;
+
+ for(; i < n; i++) {
+ t = btf_type_by_id(btf, i);
+ if (BTF_INFO_KIND(t->info) != BTF_KIND_DATASEC)
+ continue;
+
+ tname = btf_name_by_offset(btf, t->name_off);
+ if (!strcmp(tname, ".data..percpu"))
+ return i;
+ }
+
+ return -ENOENT;
+}
+
+/* replace pseudo btf_id with kernel symbol address */
+static int check_pseudo_btf_id(struct bpf_verifier_env *env,
+ struct bpf_insn *insn,
+ struct bpf_insn_aux_data *aux)
+{
+ const struct btf_var_secinfo *vsi;
+ const struct btf_type *datasec;
+ struct btf_mod_pair *btf_mod;
+ const struct btf_type *t;
+ const char *sym_name;
+ bool percpu = false;
+ u32 type, id = insn->imm;
+ struct btf *btf;
+ s32 datasec_id;
+ u64 addr;
+ int i, btf_fd, err;
+
+ btf_fd = insn[1].imm;
+ if (btf_fd) {
+ btf = btf_get_by_fd(btf_fd);
+ if (IS_ERR(btf)) {
+ verbose(env, "invalid module BTF object FD specified.\n");
+ return -EINVAL;
+ }
+ } else {
+ if (!btf_vmlinux) {
+ verbose(env, "kernel is missing BTF, make sure CONFIG_DEBUG_INFO_BTF=y is specified in Kconfig.\n");
+ return -EINVAL;
+ }
+ btf = btf_vmlinux;
+ btf_get(btf);
+ }
+
+ t = btf_type_by_id(btf, id);
+ if (!t) {
+ verbose(env, "ldimm64 insn specifies invalid btf_id %d.\n", id);
+ err = -ENOENT;
+ goto err_put;
+ }
+
+ if (!btf_type_is_var(t) && !btf_type_is_func(t)) {
+ verbose(env, "pseudo btf_id %d in ldimm64 isn't KIND_VAR or KIND_FUNC\n", id);
+ err = -EINVAL;
+ goto err_put;
+ }
+
+ sym_name = btf_name_by_offset(btf, t->name_off);
+ addr = kallsyms_lookup_name(sym_name);
+ if (!addr) {
+ verbose(env, "ldimm64 failed to find the address for kernel symbol '%s'.\n",
+ sym_name);
+ err = -ENOENT;
+ goto err_put;
+ }
+ insn[0].imm = (u32)addr;
+ insn[1].imm = addr >> 32;
+
+ if (btf_type_is_func(t)) {
+ aux->btf_var.reg_type = PTR_TO_MEM | MEM_RDONLY;
+ aux->btf_var.mem_size = 0;
+ goto check_btf;
+ }
+
+ datasec_id = find_btf_percpu_datasec(btf);
+ if (datasec_id > 0) {
+ datasec = btf_type_by_id(btf, datasec_id);
+ for_each_vsi(i, datasec, vsi) {
+ if (vsi->type == id) {
+ percpu = true;
+ break;
+ }
+ }
+ }
+
+ type = t->type;
+ t = btf_type_skip_modifiers(btf, type, NULL);
+ if (percpu) {
+ aux->btf_var.reg_type = PTR_TO_BTF_ID | MEM_PERCPU;
+ aux->btf_var.btf = btf;
+ aux->btf_var.btf_id = type;
+ } else if (!btf_type_is_struct(t)) {
+ const struct btf_type *ret;
+ const char *tname;
+ u32 tsize;
+
+ /* resolve the type size of ksym. */
+ ret = btf_resolve_size(btf, t, &tsize);
+ if (IS_ERR(ret)) {
+ tname = btf_name_by_offset(btf, t->name_off);
+ verbose(env, "ldimm64 unable to resolve the size of type '%s': %ld\n",
+ tname, PTR_ERR(ret));
+ err = -EINVAL;
+ goto err_put;
+ }
+ aux->btf_var.reg_type = PTR_TO_MEM | MEM_RDONLY;
+ aux->btf_var.mem_size = tsize;
+ } else {
+ aux->btf_var.reg_type = PTR_TO_BTF_ID;
+ aux->btf_var.btf = btf;
+ aux->btf_var.btf_id = type;
+ }
+check_btf:
+ /* check whether we recorded this BTF (and maybe module) already */
+ for (i = 0; i < env->used_btf_cnt; i++) {
+ if (env->used_btfs[i].btf == btf) {
+ btf_put(btf);
+ return 0;
+ }
+ }
+
+ if (env->used_btf_cnt >= MAX_USED_BTFS) {
+ err = -E2BIG;
+ goto err_put;
+ }
+
+ btf_mod = &env->used_btfs[env->used_btf_cnt];
+ btf_mod->btf = btf;
+ btf_mod->module = NULL;
+
+ /* if we reference variables from kernel module, bump its refcount */
+ if (btf_is_module(btf)) {
+ btf_mod->module = btf_try_get_module(btf);
+ if (!btf_mod->module) {
+ err = -ENXIO;
+ goto err_put;
+ }
+ }
+
+ env->used_btf_cnt++;
+
+ return 0;
+err_put:
+ btf_put(btf);
+ return err;
+}
+
+static bool is_tracing_prog_type(enum bpf_prog_type type)
+{
+ switch (type) {
+ case BPF_PROG_TYPE_KPROBE:
+ case BPF_PROG_TYPE_TRACEPOINT:
+ case BPF_PROG_TYPE_PERF_EVENT:
+ case BPF_PROG_TYPE_RAW_TRACEPOINT:
+ case BPF_PROG_TYPE_RAW_TRACEPOINT_WRITABLE:
+ return true;
+ default:
+ return false;
+ }
+}
+
+static int check_map_prog_compatibility(struct bpf_verifier_env *env,
+ struct bpf_map *map,
+ struct bpf_prog *prog)
+
+{
+ enum bpf_prog_type prog_type = resolve_prog_type(prog);
+
+ if (btf_record_has_field(map->record, BPF_LIST_HEAD) ||
+ btf_record_has_field(map->record, BPF_RB_ROOT)) {
+ if (is_tracing_prog_type(prog_type)) {
+ verbose(env, "tracing progs cannot use bpf_{list_head,rb_root} yet\n");
+ return -EINVAL;
+ }
+ }
+
+ if (btf_record_has_field(map->record, BPF_SPIN_LOCK)) {
+ if (prog_type == BPF_PROG_TYPE_SOCKET_FILTER) {
+ verbose(env, "socket filter progs cannot use bpf_spin_lock yet\n");
+ return -EINVAL;
+ }
+
+ if (is_tracing_prog_type(prog_type)) {
+ verbose(env, "tracing progs cannot use bpf_spin_lock yet\n");
+ return -EINVAL;
+ }
+ }
+
+ if (btf_record_has_field(map->record, BPF_TIMER)) {
+ if (is_tracing_prog_type(prog_type)) {
+ verbose(env, "tracing progs cannot use bpf_timer yet\n");
+ return -EINVAL;
+ }
+ }
+
+ if ((bpf_prog_is_offloaded(prog->aux) || bpf_map_is_offloaded(map)) &&
+ !bpf_offload_prog_map_match(prog, map)) {
+ verbose(env, "offload device mismatch between prog and map\n");
+ return -EINVAL;
+ }
+
+ if (map->map_type == BPF_MAP_TYPE_STRUCT_OPS) {
+ verbose(env, "bpf_struct_ops map cannot be used in prog\n");
+ return -EINVAL;
+ }
+
+ if (prog->aux->sleepable)
+ switch (map->map_type) {
+ case BPF_MAP_TYPE_HASH:
+ case BPF_MAP_TYPE_LRU_HASH:
+ case BPF_MAP_TYPE_ARRAY:
+ case BPF_MAP_TYPE_PERCPU_HASH:
+ case BPF_MAP_TYPE_PERCPU_ARRAY:
+ case BPF_MAP_TYPE_LRU_PERCPU_HASH:
+ case BPF_MAP_TYPE_ARRAY_OF_MAPS:
+ case BPF_MAP_TYPE_HASH_OF_MAPS:
+ case BPF_MAP_TYPE_RINGBUF:
+ case BPF_MAP_TYPE_USER_RINGBUF:
+ case BPF_MAP_TYPE_INODE_STORAGE:
+ case BPF_MAP_TYPE_SK_STORAGE:
+ case BPF_MAP_TYPE_TASK_STORAGE:
+ case BPF_MAP_TYPE_CGRP_STORAGE:
+ break;
+ default:
+ verbose(env,
+ "Sleepable programs can only use array, hash, ringbuf and local storage maps\n");
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
+static bool bpf_map_is_cgroup_storage(struct bpf_map *map)
+{
+ return (map->map_type == BPF_MAP_TYPE_CGROUP_STORAGE ||
+ map->map_type == BPF_MAP_TYPE_PERCPU_CGROUP_STORAGE);
+}
+
+/* find and rewrite pseudo imm in ld_imm64 instructions:
+ *
+ * 1. if it accesses map FD, replace it with actual map pointer.
+ * 2. if it accesses btf_id of a VAR, replace it with pointer to the var.
+ *
+ * NOTE: btf_vmlinux is required for converting pseudo btf_id.
+ */
+static int resolve_pseudo_ldimm64(struct bpf_verifier_env *env)
+{
+ struct bpf_insn *insn = env->prog->insnsi;
+ int insn_cnt = env->prog->len;
+ int i, j, err;
+
+ err = bpf_prog_calc_tag(env->prog);
+ if (err)
+ return err;
+
+ for (i = 0; i < insn_cnt; i++, insn++) {
+ if (BPF_CLASS(insn->code) == BPF_LDX &&
+ ((BPF_MODE(insn->code) != BPF_MEM && BPF_MODE(insn->code) != BPF_MEMSX) ||
+ insn->imm != 0)) {
+ verbose(env, "BPF_LDX uses reserved fields\n");
+ return -EINVAL;
+ }
+
+ if (insn[0].code == (BPF_LD | BPF_IMM | BPF_DW)) {
+ struct bpf_insn_aux_data *aux;
+ struct bpf_map *map;
+ struct fd f;
+ u64 addr;
+ u32 fd;
+
+ if (i == insn_cnt - 1 || insn[1].code != 0 ||
+ insn[1].dst_reg != 0 || insn[1].src_reg != 0 ||
+ insn[1].off != 0) {
+ verbose(env, "invalid bpf_ld_imm64 insn\n");
+ return -EINVAL;
+ }
+
+ if (insn[0].src_reg == 0)
+ /* valid generic load 64-bit imm */
+ goto next_insn;
+
+ if (insn[0].src_reg == BPF_PSEUDO_BTF_ID) {
+ aux = &env->insn_aux_data[i];
+ err = check_pseudo_btf_id(env, insn, aux);
+ if (err)
+ return err;
+ goto next_insn;
+ }
+
+ if (insn[0].src_reg == BPF_PSEUDO_FUNC) {
+ aux = &env->insn_aux_data[i];
+ aux->ptr_type = PTR_TO_FUNC;
+ goto next_insn;
+ }
+
+ /* In final convert_pseudo_ld_imm64() step, this is
+ * converted into regular 64-bit imm load insn.
+ */
+ switch (insn[0].src_reg) {
+ case BPF_PSEUDO_MAP_VALUE:
+ case BPF_PSEUDO_MAP_IDX_VALUE:
+ break;
+ case BPF_PSEUDO_MAP_FD:
+ case BPF_PSEUDO_MAP_IDX:
+ if (insn[1].imm == 0)
+ break;
+ fallthrough;
+ default:
+ verbose(env, "unrecognized bpf_ld_imm64 insn\n");
+ return -EINVAL;
+ }
+
+ switch (insn[0].src_reg) {
+ case BPF_PSEUDO_MAP_IDX_VALUE:
+ case BPF_PSEUDO_MAP_IDX:
+ if (bpfptr_is_null(env->fd_array)) {
+ verbose(env, "fd_idx without fd_array is invalid\n");
+ return -EPROTO;
+ }
+ if (copy_from_bpfptr_offset(&fd, env->fd_array,
+ insn[0].imm * sizeof(fd),
+ sizeof(fd)))
+ return -EFAULT;
+ break;
+ default:
+ fd = insn[0].imm;
+ break;
+ }
+
+ f = fdget(fd);
+ map = __bpf_map_get(f);
+ if (IS_ERR(map)) {
+ verbose(env, "fd %d is not pointing to valid bpf_map\n",
+ insn[0].imm);
+ return PTR_ERR(map);
+ }
+
+ err = check_map_prog_compatibility(env, map, env->prog);
+ if (err) {
+ fdput(f);
+ return err;
+ }
+
+ aux = &env->insn_aux_data[i];
+ if (insn[0].src_reg == BPF_PSEUDO_MAP_FD ||
+ insn[0].src_reg == BPF_PSEUDO_MAP_IDX) {
+ addr = (unsigned long)map;
+ } else {
+ u32 off = insn[1].imm;
+
+ if (off >= BPF_MAX_VAR_OFF) {
+ verbose(env, "direct value offset of %u is not allowed\n", off);
+ fdput(f);
+ return -EINVAL;
+ }
+
+ if (!map->ops->map_direct_value_addr) {
+ verbose(env, "no direct value access support for this map type\n");
+ fdput(f);
+ return -EINVAL;
+ }
+
+ err = map->ops->map_direct_value_addr(map, &addr, off);
+ if (err) {
+ verbose(env, "invalid access to map value pointer, value_size=%u off=%u\n",
+ map->value_size, off);
+ fdput(f);
+ return err;
+ }
+
+ aux->map_off = off;
+ addr += off;
+ }
+
+ insn[0].imm = (u32)addr;
+ insn[1].imm = addr >> 32;
+
+ /* check whether we recorded this map already */
+ for (j = 0; j < env->used_map_cnt; j++) {
+ if (env->used_maps[j] == map) {
+ aux->map_index = j;
+ fdput(f);
+ goto next_insn;
+ }
+ }
+
+ if (env->used_map_cnt >= MAX_USED_MAPS) {
+ fdput(f);
+ return -E2BIG;
+ }
+
+ /* hold the map. If the program is rejected by verifier,
+ * the map will be released by release_maps() or it
+ * will be used by the valid program until it's unloaded
+ * and all maps are released in free_used_maps()
+ */
+ bpf_map_inc(map);
+
+ aux->map_index = env->used_map_cnt;
+ env->used_maps[env->used_map_cnt++] = map;
+
+ if (bpf_map_is_cgroup_storage(map) &&
+ bpf_cgroup_storage_assign(env->prog->aux, map)) {
+ verbose(env, "only one cgroup storage of each type is allowed\n");
+ fdput(f);
+ return -EBUSY;
+ }
+
+ fdput(f);
+next_insn:
+ insn++;
+ i++;
+ continue;
+ }
+
+ /* Basic sanity check before we invest more work here. */
+ if (!bpf_opcode_in_insntable(insn->code)) {
+ verbose(env, "unknown opcode %02x\n", insn->code);
+ return -EINVAL;
+ }
+ }
+
+ /* now all pseudo BPF_LD_IMM64 instructions load valid
+ * 'struct bpf_map *' into a register instead of user map_fd.
+ * These pointers will be used later by verifier to validate map access.
+ */
+ return 0;
+}
+
+/* drop refcnt of maps used by the rejected program */
+static void release_maps(struct bpf_verifier_env *env)
+{
+ __bpf_free_used_maps(env->prog->aux, env->used_maps,
+ env->used_map_cnt);
+}
+
+/* drop refcnt of maps used by the rejected program */
+static void release_btfs(struct bpf_verifier_env *env)
+{
+ __bpf_free_used_btfs(env->prog->aux, env->used_btfs,
+ env->used_btf_cnt);
+}
+
+/* convert pseudo BPF_LD_IMM64 into generic BPF_LD_IMM64 */
+static void convert_pseudo_ld_imm64(struct bpf_verifier_env *env)
+{
+ struct bpf_insn *insn = env->prog->insnsi;
+ int insn_cnt = env->prog->len;
+ int i;
+
+ for (i = 0; i < insn_cnt; i++, insn++) {
+ if (insn->code != (BPF_LD | BPF_IMM | BPF_DW))
+ continue;
+ if (insn->src_reg == BPF_PSEUDO_FUNC)
+ continue;
+ insn->src_reg = 0;
+ }
+}
+
+/* single env->prog->insni[off] instruction was replaced with the range
+ * insni[off, off + cnt). Adjust corresponding insn_aux_data by copying
+ * [0, off) and [off, end) to new locations, so the patched range stays zero
+ */
+static void adjust_insn_aux_data(struct bpf_verifier_env *env,
+ struct bpf_insn_aux_data *new_data,
+ struct bpf_prog *new_prog, u32 off, u32 cnt)
+{
+ struct bpf_insn_aux_data *old_data = env->insn_aux_data;
+ struct bpf_insn *insn = new_prog->insnsi;
+ u32 old_seen = old_data[off].seen;
+ u32 prog_len;
+ int i;
+
+ /* aux info at OFF always needs adjustment, no matter fast path
+ * (cnt == 1) is taken or not. There is no guarantee INSN at OFF is the
+ * original insn at old prog.
+ */
+ old_data[off].zext_dst = insn_has_def32(env, insn + off + cnt - 1);
+
+ if (cnt == 1)
+ return;
+ prog_len = new_prog->len;
+
+ memcpy(new_data, old_data, sizeof(struct bpf_insn_aux_data) * off);
+ memcpy(new_data + off + cnt - 1, old_data + off,
+ sizeof(struct bpf_insn_aux_data) * (prog_len - off - cnt + 1));
+ for (i = off; i < off + cnt - 1; i++) {
+ /* Expand insni[off]'s seen count to the patched range. */
+ new_data[i].seen = old_seen;
+ new_data[i].zext_dst = insn_has_def32(env, insn + i);
+ }
+ env->insn_aux_data = new_data;
+ vfree(old_data);
+}
+
+static void adjust_subprog_starts(struct bpf_verifier_env *env, u32 off, u32 len)
+{
+ int i;
+
+ if (len == 1)
+ return;
+ /* NOTE: fake 'exit' subprog should be updated as well. */
+ for (i = 0; i <= env->subprog_cnt; i++) {
+ if (env->subprog_info[i].start <= off)
+ continue;
+ env->subprog_info[i].start += len - 1;
+ }
+}
+
+static void adjust_poke_descs(struct bpf_prog *prog, u32 off, u32 len)
+{
+ struct bpf_jit_poke_descriptor *tab = prog->aux->poke_tab;
+ int i, sz = prog->aux->size_poke_tab;
+ struct bpf_jit_poke_descriptor *desc;
+
+ for (i = 0; i < sz; i++) {
+ desc = &tab[i];
+ if (desc->insn_idx <= off)
+ continue;
+ desc->insn_idx += len - 1;
+ }
+}
+
+static struct bpf_prog *bpf_patch_insn_data(struct bpf_verifier_env *env, u32 off,
+ const struct bpf_insn *patch, u32 len)
+{
+ struct bpf_prog *new_prog;
+ struct bpf_insn_aux_data *new_data = NULL;
+
+ if (len > 1) {
+ new_data = vzalloc(array_size(env->prog->len + len - 1,
+ sizeof(struct bpf_insn_aux_data)));
+ if (!new_data)
+ return NULL;
+ }
+
+ new_prog = bpf_patch_insn_single(env->prog, off, patch, len);
+ if (IS_ERR(new_prog)) {
+ if (PTR_ERR(new_prog) == -ERANGE)
+ verbose(env,
+ "insn %d cannot be patched due to 16-bit range\n",
+ env->insn_aux_data[off].orig_idx);
+ vfree(new_data);
+ return NULL;
+ }
+ adjust_insn_aux_data(env, new_data, new_prog, off, len);
+ adjust_subprog_starts(env, off, len);
+ adjust_poke_descs(new_prog, off, len);
+ return new_prog;
+}
+
+static int adjust_subprog_starts_after_remove(struct bpf_verifier_env *env,
+ u32 off, u32 cnt)
+{
+ int i, j;
+
+ /* find first prog starting at or after off (first to remove) */
+ for (i = 0; i < env->subprog_cnt; i++)
+ if (env->subprog_info[i].start >= off)
+ break;
+ /* find first prog starting at or after off + cnt (first to stay) */
+ for (j = i; j < env->subprog_cnt; j++)
+ if (env->subprog_info[j].start >= off + cnt)
+ break;
+ /* if j doesn't start exactly at off + cnt, we are just removing
+ * the front of previous prog
+ */
+ if (env->subprog_info[j].start != off + cnt)
+ j--;
+
+ if (j > i) {
+ struct bpf_prog_aux *aux = env->prog->aux;
+ int move;
+
+ /* move fake 'exit' subprog as well */
+ move = env->subprog_cnt + 1 - j;
+
+ memmove(env->subprog_info + i,
+ env->subprog_info + j,
+ sizeof(*env->subprog_info) * move);
+ env->subprog_cnt -= j - i;
+
+ /* remove func_info */
+ if (aux->func_info) {
+ move = aux->func_info_cnt - j;
+
+ memmove(aux->func_info + i,
+ aux->func_info + j,
+ sizeof(*aux->func_info) * move);
+ aux->func_info_cnt -= j - i;
+ /* func_info->insn_off is set after all code rewrites,
+ * in adjust_btf_func() - no need to adjust
+ */
+ }
+ } else {
+ /* convert i from "first prog to remove" to "first to adjust" */
+ if (env->subprog_info[i].start == off)
+ i++;
+ }
+
+ /* update fake 'exit' subprog as well */
+ for (; i <= env->subprog_cnt; i++)
+ env->subprog_info[i].start -= cnt;
+
+ return 0;
+}
+
+static int bpf_adj_linfo_after_remove(struct bpf_verifier_env *env, u32 off,
+ u32 cnt)
+{
+ struct bpf_prog *prog = env->prog;
+ u32 i, l_off, l_cnt, nr_linfo;
+ struct bpf_line_info *linfo;
+
+ nr_linfo = prog->aux->nr_linfo;
+ if (!nr_linfo)
+ return 0;
+
+ linfo = prog->aux->linfo;
+
+ /* find first line info to remove, count lines to be removed */
+ for (i = 0; i < nr_linfo; i++)
+ if (linfo[i].insn_off >= off)
+ break;
+
+ l_off = i;
+ l_cnt = 0;
+ for (; i < nr_linfo; i++)
+ if (linfo[i].insn_off < off + cnt)
+ l_cnt++;
+ else
+ break;
+
+ /* First live insn doesn't match first live linfo, it needs to "inherit"
+ * last removed linfo. prog is already modified, so prog->len == off
+ * means no live instructions after (tail of the program was removed).
+ */
+ if (prog->len != off && l_cnt &&
+ (i == nr_linfo || linfo[i].insn_off != off + cnt)) {
+ l_cnt--;
+ linfo[--i].insn_off = off + cnt;
+ }
+
+ /* remove the line info which refer to the removed instructions */
+ if (l_cnt) {
+ memmove(linfo + l_off, linfo + i,
+ sizeof(*linfo) * (nr_linfo - i));
+
+ prog->aux->nr_linfo -= l_cnt;
+ nr_linfo = prog->aux->nr_linfo;
+ }
+
+ /* pull all linfo[i].insn_off >= off + cnt in by cnt */
+ for (i = l_off; i < nr_linfo; i++)
+ linfo[i].insn_off -= cnt;
+
+ /* fix up all subprogs (incl. 'exit') which start >= off */
+ for (i = 0; i <= env->subprog_cnt; i++)
+ if (env->subprog_info[i].linfo_idx > l_off) {
+ /* program may have started in the removed region but
+ * may not be fully removed
+ */
+ if (env->subprog_info[i].linfo_idx >= l_off + l_cnt)
+ env->subprog_info[i].linfo_idx -= l_cnt;
+ else
+ env->subprog_info[i].linfo_idx = l_off;
+ }
+
+ return 0;
+}
+
+static int verifier_remove_insns(struct bpf_verifier_env *env, u32 off, u32 cnt)
+{
+ struct bpf_insn_aux_data *aux_data = env->insn_aux_data;
+ unsigned int orig_prog_len = env->prog->len;
+ int err;
+
+ if (bpf_prog_is_offloaded(env->prog->aux))
+ bpf_prog_offload_remove_insns(env, off, cnt);
+
+ err = bpf_remove_insns(env->prog, off, cnt);
+ if (err)
+ return err;
+
+ err = adjust_subprog_starts_after_remove(env, off, cnt);
+ if (err)
+ return err;
+
+ err = bpf_adj_linfo_after_remove(env, off, cnt);
+ if (err)
+ return err;
+
+ memmove(aux_data + off, aux_data + off + cnt,
+ sizeof(*aux_data) * (orig_prog_len - off - cnt));
+
+ return 0;
+}
+
+/* The verifier does more data flow analysis than llvm and will not
+ * explore branches that are dead at run time. Malicious programs can
+ * have dead code too. Therefore replace all dead at-run-time code
+ * with 'ja -1'.
+ *
+ * Just nops are not optimal, e.g. if they would sit at the end of the
+ * program and through another bug we would manage to jump there, then
+ * we'd execute beyond program memory otherwise. Returning exception
+ * code also wouldn't work since we can have subprogs where the dead
+ * code could be located.
+ */
+static void sanitize_dead_code(struct bpf_verifier_env *env)
+{
+ struct bpf_insn_aux_data *aux_data = env->insn_aux_data;
+ struct bpf_insn trap = BPF_JMP_IMM(BPF_JA, 0, 0, -1);
+ struct bpf_insn *insn = env->prog->insnsi;
+ const int insn_cnt = env->prog->len;
+ int i;
+
+ for (i = 0; i < insn_cnt; i++) {
+ if (aux_data[i].seen)
+ continue;
+ memcpy(insn + i, &trap, sizeof(trap));
+ aux_data[i].zext_dst = false;
+ }
+}
+
+static bool insn_is_cond_jump(u8 code)
+{
+ u8 op;
+
+ op = BPF_OP(code);
+ if (BPF_CLASS(code) == BPF_JMP32)
+ return op != BPF_JA;
+
+ if (BPF_CLASS(code) != BPF_JMP)
+ return false;
+
+ return op != BPF_JA && op != BPF_EXIT && op != BPF_CALL;
+}
+
+static void opt_hard_wire_dead_code_branches(struct bpf_verifier_env *env)
+{
+ struct bpf_insn_aux_data *aux_data = env->insn_aux_data;
+ struct bpf_insn ja = BPF_JMP_IMM(BPF_JA, 0, 0, 0);
+ struct bpf_insn *insn = env->prog->insnsi;
+ const int insn_cnt = env->prog->len;
+ int i;
+
+ for (i = 0; i < insn_cnt; i++, insn++) {
+ if (!insn_is_cond_jump(insn->code))
+ continue;
+
+ if (!aux_data[i + 1].seen)
+ ja.off = insn->off;
+ else if (!aux_data[i + 1 + insn->off].seen)
+ ja.off = 0;
+ else
+ continue;
+
+ if (bpf_prog_is_offloaded(env->prog->aux))
+ bpf_prog_offload_replace_insn(env, i, &ja);
+
+ memcpy(insn, &ja, sizeof(ja));
+ }
+}
+
+static int opt_remove_dead_code(struct bpf_verifier_env *env)
+{
+ struct bpf_insn_aux_data *aux_data = env->insn_aux_data;
+ int insn_cnt = env->prog->len;
+ int i, err;
+
+ for (i = 0; i < insn_cnt; i++) {
+ int j;
+
+ j = 0;
+ while (i + j < insn_cnt && !aux_data[i + j].seen)
+ j++;
+ if (!j)
+ continue;
+
+ err = verifier_remove_insns(env, i, j);
+ if (err)
+ return err;
+ insn_cnt = env->prog->len;
+ }
+
+ return 0;
+}
+
+static int opt_remove_nops(struct bpf_verifier_env *env)
+{
+ const struct bpf_insn ja = BPF_JMP_IMM(BPF_JA, 0, 0, 0);
+ struct bpf_insn *insn = env->prog->insnsi;
+ int insn_cnt = env->prog->len;
+ int i, err;
+
+ for (i = 0; i < insn_cnt; i++) {
+ if (memcmp(&insn[i], &ja, sizeof(ja)))
+ continue;
+
+ err = verifier_remove_insns(env, i, 1);
+ if (err)
+ return err;
+ insn_cnt--;
+ i--;
+ }
+
+ return 0;
+}
+
+static int opt_subreg_zext_lo32_rnd_hi32(struct bpf_verifier_env *env,
+ const union bpf_attr *attr)
+{
+ struct bpf_insn *patch, zext_patch[2], rnd_hi32_patch[4];
+ struct bpf_insn_aux_data *aux = env->insn_aux_data;
+ int i, patch_len, delta = 0, len = env->prog->len;
+ struct bpf_insn *insns = env->prog->insnsi;
+ struct bpf_prog *new_prog;
+ bool rnd_hi32;
+
+ rnd_hi32 = attr->prog_flags & BPF_F_TEST_RND_HI32;
+ zext_patch[1] = BPF_ZEXT_REG(0);
+ rnd_hi32_patch[1] = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, 0);
+ rnd_hi32_patch[2] = BPF_ALU64_IMM(BPF_LSH, BPF_REG_AX, 32);
+ rnd_hi32_patch[3] = BPF_ALU64_REG(BPF_OR, 0, BPF_REG_AX);
+ for (i = 0; i < len; i++) {
+ int adj_idx = i + delta;
+ struct bpf_insn insn;
+ int load_reg;
+
+ insn = insns[adj_idx];
+ load_reg = insn_def_regno(&insn);
+ if (!aux[adj_idx].zext_dst) {
+ u8 code, class;
+ u32 imm_rnd;
+
+ if (!rnd_hi32)
+ continue;
+
+ code = insn.code;
+ class = BPF_CLASS(code);
+ if (load_reg == -1)
+ continue;
+
+ /* NOTE: arg "reg" (the fourth one) is only used for
+ * BPF_STX + SRC_OP, so it is safe to pass NULL
+ * here.
+ */
+ if (is_reg64(env, &insn, load_reg, NULL, DST_OP)) {
+ if (class == BPF_LD &&
+ BPF_MODE(code) == BPF_IMM)
+ i++;
+ continue;
+ }
+
+ /* ctx load could be transformed into wider load. */
+ if (class == BPF_LDX &&
+ aux[adj_idx].ptr_type == PTR_TO_CTX)
+ continue;
+
+ imm_rnd = get_random_u32();
+ rnd_hi32_patch[0] = insn;
+ rnd_hi32_patch[1].imm = imm_rnd;
+ rnd_hi32_patch[3].dst_reg = load_reg;
+ patch = rnd_hi32_patch;
+ patch_len = 4;
+ goto apply_patch_buffer;
+ }
+
+ /* Add in an zero-extend instruction if a) the JIT has requested
+ * it or b) it's a CMPXCHG.
+ *
+ * The latter is because: BPF_CMPXCHG always loads a value into
+ * R0, therefore always zero-extends. However some archs'
+ * equivalent instruction only does this load when the
+ * comparison is successful. This detail of CMPXCHG is
+ * orthogonal to the general zero-extension behaviour of the
+ * CPU, so it's treated independently of bpf_jit_needs_zext.
+ */
+ if (!bpf_jit_needs_zext() && !is_cmpxchg_insn(&insn))
+ continue;
+
+ /* Zero-extension is done by the caller. */
+ if (bpf_pseudo_kfunc_call(&insn))
+ continue;
+
+ if (WARN_ON(load_reg == -1)) {
+ verbose(env, "verifier bug. zext_dst is set, but no reg is defined\n");
+ return -EFAULT;
+ }
+
+ zext_patch[0] = insn;
+ zext_patch[1].dst_reg = load_reg;
+ zext_patch[1].src_reg = load_reg;
+ patch = zext_patch;
+ patch_len = 2;
+apply_patch_buffer:
+ new_prog = bpf_patch_insn_data(env, adj_idx, patch, patch_len);
+ if (!new_prog)
+ return -ENOMEM;
+ env->prog = new_prog;
+ insns = new_prog->insnsi;
+ aux = env->insn_aux_data;
+ delta += patch_len - 1;
+ }
+
+ return 0;
+}
+
+/* convert load instructions that access fields of a context type into a
+ * sequence of instructions that access fields of the underlying structure:
+ * struct __sk_buff -> struct sk_buff
+ * struct bpf_sock_ops -> struct sock
+ */
+static int convert_ctx_accesses(struct bpf_verifier_env *env)
+{
+ const struct bpf_verifier_ops *ops = env->ops;
+ int i, cnt, size, ctx_field_size, delta = 0;
+ const int insn_cnt = env->prog->len;
+ struct bpf_insn insn_buf[16], *insn;
+ u32 target_size, size_default, off;
+ struct bpf_prog *new_prog;
+ enum bpf_access_type type;
+ bool is_narrower_load;
+
+ if (ops->gen_prologue || env->seen_direct_write) {
+ if (!ops->gen_prologue) {
+ verbose(env, "bpf verifier is misconfigured\n");
+ return -EINVAL;
+ }
+ cnt = ops->gen_prologue(insn_buf, env->seen_direct_write,
+ env->prog);
+ if (cnt >= ARRAY_SIZE(insn_buf)) {
+ verbose(env, "bpf verifier is misconfigured\n");
+ return -EINVAL;
+ } else if (cnt) {
+ new_prog = bpf_patch_insn_data(env, 0, insn_buf, cnt);
+ if (!new_prog)
+ return -ENOMEM;
+
+ env->prog = new_prog;
+ delta += cnt - 1;
+ }
+ }
+
+ if (bpf_prog_is_offloaded(env->prog->aux))
+ return 0;
+
+ insn = env->prog->insnsi + delta;
+
+ for (i = 0; i < insn_cnt; i++, insn++) {
+ bpf_convert_ctx_access_t convert_ctx_access;
+ u8 mode;
+
+ if (insn->code == (BPF_LDX | BPF_MEM | BPF_B) ||
+ insn->code == (BPF_LDX | BPF_MEM | BPF_H) ||
+ insn->code == (BPF_LDX | BPF_MEM | BPF_W) ||
+ insn->code == (BPF_LDX | BPF_MEM | BPF_DW) ||
+ insn->code == (BPF_LDX | BPF_MEMSX | BPF_B) ||
+ insn->code == (BPF_LDX | BPF_MEMSX | BPF_H) ||
+ insn->code == (BPF_LDX | BPF_MEMSX | BPF_W)) {
+ type = BPF_READ;
+ } else if (insn->code == (BPF_STX | BPF_MEM | BPF_B) ||
+ insn->code == (BPF_STX | BPF_MEM | BPF_H) ||
+ insn->code == (BPF_STX | BPF_MEM | BPF_W) ||
+ insn->code == (BPF_STX | BPF_MEM | BPF_DW) ||
+ insn->code == (BPF_ST | BPF_MEM | BPF_B) ||
+ insn->code == (BPF_ST | BPF_MEM | BPF_H) ||
+ insn->code == (BPF_ST | BPF_MEM | BPF_W) ||
+ insn->code == (BPF_ST | BPF_MEM | BPF_DW)) {
+ type = BPF_WRITE;
+ } else {
+ continue;
+ }
+
+ if (type == BPF_WRITE &&
+ env->insn_aux_data[i + delta].sanitize_stack_spill) {
+ struct bpf_insn patch[] = {
+ *insn,
+ BPF_ST_NOSPEC(),
+ };
+
+ cnt = ARRAY_SIZE(patch);
+ new_prog = bpf_patch_insn_data(env, i + delta, patch, cnt);
+ if (!new_prog)
+ return -ENOMEM;
+
+ delta += cnt - 1;
+ env->prog = new_prog;
+ insn = new_prog->insnsi + i + delta;
+ continue;
+ }
+
+ switch ((int)env->insn_aux_data[i + delta].ptr_type) {
+ case PTR_TO_CTX:
+ if (!ops->convert_ctx_access)
+ continue;
+ convert_ctx_access = ops->convert_ctx_access;
+ break;
+ case PTR_TO_SOCKET:
+ case PTR_TO_SOCK_COMMON:
+ convert_ctx_access = bpf_sock_convert_ctx_access;
+ break;
+ case PTR_TO_TCP_SOCK:
+ convert_ctx_access = bpf_tcp_sock_convert_ctx_access;
+ break;
+ case PTR_TO_XDP_SOCK:
+ convert_ctx_access = bpf_xdp_sock_convert_ctx_access;
+ break;
+ case PTR_TO_BTF_ID:
+ case PTR_TO_BTF_ID | PTR_UNTRUSTED:
+ /* PTR_TO_BTF_ID | MEM_ALLOC always has a valid lifetime, unlike
+ * PTR_TO_BTF_ID, and an active ref_obj_id, but the same cannot
+ * be said once it is marked PTR_UNTRUSTED, hence we must handle
+ * any faults for loads into such types. BPF_WRITE is disallowed
+ * for this case.
+ */
+ case PTR_TO_BTF_ID | MEM_ALLOC | PTR_UNTRUSTED:
+ if (type == BPF_READ) {
+ if (BPF_MODE(insn->code) == BPF_MEM)
+ insn->code = BPF_LDX | BPF_PROBE_MEM |
+ BPF_SIZE((insn)->code);
+ else
+ insn->code = BPF_LDX | BPF_PROBE_MEMSX |
+ BPF_SIZE((insn)->code);
+ env->prog->aux->num_exentries++;
+ }
+ continue;
+ default:
+ continue;
+ }
+
+ ctx_field_size = env->insn_aux_data[i + delta].ctx_field_size;
+ size = BPF_LDST_BYTES(insn);
+ mode = BPF_MODE(insn->code);
+
+ /* If the read access is a narrower load of the field,
+ * convert to a 4/8-byte load, to minimum program type specific
+ * convert_ctx_access changes. If conversion is successful,
+ * we will apply proper mask to the result.
+ */
+ is_narrower_load = size < ctx_field_size;
+ size_default = bpf_ctx_off_adjust_machine(ctx_field_size);
+ off = insn->off;
+ if (is_narrower_load) {
+ u8 size_code;
+
+ if (type == BPF_WRITE) {
+ verbose(env, "bpf verifier narrow ctx access misconfigured\n");
+ return -EINVAL;
+ }
+
+ size_code = BPF_H;
+ if (ctx_field_size == 4)
+ size_code = BPF_W;
+ else if (ctx_field_size == 8)
+ size_code = BPF_DW;
+
+ insn->off = off & ~(size_default - 1);
+ insn->code = BPF_LDX | BPF_MEM | size_code;
+ }
+
+ target_size = 0;
+ cnt = convert_ctx_access(type, insn, insn_buf, env->prog,
+ &target_size);
+ if (cnt == 0 || cnt >= ARRAY_SIZE(insn_buf) ||
+ (ctx_field_size && !target_size)) {
+ verbose(env, "bpf verifier is misconfigured\n");
+ return -EINVAL;
+ }
+
+ if (is_narrower_load && size < target_size) {
+ u8 shift = bpf_ctx_narrow_access_offset(
+ off, size, size_default) * 8;
+ if (shift && cnt + 1 >= ARRAY_SIZE(insn_buf)) {
+ verbose(env, "bpf verifier narrow ctx load misconfigured\n");
+ return -EINVAL;
+ }
+ if (ctx_field_size <= 4) {
+ if (shift)
+ insn_buf[cnt++] = BPF_ALU32_IMM(BPF_RSH,
+ insn->dst_reg,
+ shift);
+ insn_buf[cnt++] = BPF_ALU32_IMM(BPF_AND, insn->dst_reg,
+ (1 << size * 8) - 1);
+ } else {
+ if (shift)
+ insn_buf[cnt++] = BPF_ALU64_IMM(BPF_RSH,
+ insn->dst_reg,
+ shift);
+ insn_buf[cnt++] = BPF_ALU32_IMM(BPF_AND, insn->dst_reg,
+ (1ULL << size * 8) - 1);
+ }
+ }
+ if (mode == BPF_MEMSX)
+ insn_buf[cnt++] = BPF_RAW_INSN(BPF_ALU64 | BPF_MOV | BPF_X,
+ insn->dst_reg, insn->dst_reg,
+ size * 8, 0);
+
+ new_prog = bpf_patch_insn_data(env, i + delta, insn_buf, cnt);
+ if (!new_prog)
+ return -ENOMEM;
+
+ delta += cnt - 1;
+
+ /* keep walking new program and skip insns we just inserted */
+ env->prog = new_prog;
+ insn = new_prog->insnsi + i + delta;
+ }
+
+ return 0;
+}
+
+static int jit_subprogs(struct bpf_verifier_env *env)
+{
+ struct bpf_prog *prog = env->prog, **func, *tmp;
+ int i, j, subprog_start, subprog_end = 0, len, subprog;
+ struct bpf_map *map_ptr;
+ struct bpf_insn *insn;
+ void *old_bpf_func;
+ int err, num_exentries;
+
+ if (env->subprog_cnt <= 1)
+ return 0;
+
+ for (i = 0, insn = prog->insnsi; i < prog->len; i++, insn++) {
+ if (!bpf_pseudo_func(insn) && !bpf_pseudo_call(insn))
+ continue;
+
+ /* Upon error here we cannot fall back to interpreter but
+ * need a hard reject of the program. Thus -EFAULT is
+ * propagated in any case.
+ */
+ subprog = find_subprog(env, i + insn->imm + 1);
+ if (subprog < 0) {
+ WARN_ONCE(1, "verifier bug. No program starts at insn %d\n",
+ i + insn->imm + 1);
+ return -EFAULT;
+ }
+ /* temporarily remember subprog id inside insn instead of
+ * aux_data, since next loop will split up all insns into funcs
+ */
+ insn->off = subprog;
+ /* remember original imm in case JIT fails and fallback
+ * to interpreter will be needed
+ */
+ env->insn_aux_data[i].call_imm = insn->imm;
+ /* point imm to __bpf_call_base+1 from JITs point of view */
+ insn->imm = 1;
+ if (bpf_pseudo_func(insn))
+ /* jit (e.g. x86_64) may emit fewer instructions
+ * if it learns a u32 imm is the same as a u64 imm.
+ * Force a non zero here.
+ */
+ insn[1].imm = 1;
+ }
+
+ err = bpf_prog_alloc_jited_linfo(prog);
+ if (err)
+ goto out_undo_insn;
+
+ err = -ENOMEM;
+ func = kcalloc(env->subprog_cnt, sizeof(prog), GFP_KERNEL);
+ if (!func)
+ goto out_undo_insn;
+
+ for (i = 0; i < env->subprog_cnt; i++) {
+ subprog_start = subprog_end;
+ subprog_end = env->subprog_info[i + 1].start;
+
+ len = subprog_end - subprog_start;
+ /* bpf_prog_run() doesn't call subprogs directly,
+ * hence main prog stats include the runtime of subprogs.
+ * subprogs don't have IDs and not reachable via prog_get_next_id
+ * func[i]->stats will never be accessed and stays NULL
+ */
+ func[i] = bpf_prog_alloc_no_stats(bpf_prog_size(len), GFP_USER);
+ if (!func[i])
+ goto out_free;
+ memcpy(func[i]->insnsi, &prog->insnsi[subprog_start],
+ len * sizeof(struct bpf_insn));
+ func[i]->type = prog->type;
+ func[i]->len = len;
+ if (bpf_prog_calc_tag(func[i]))
+ goto out_free;
+ func[i]->is_func = 1;
+ func[i]->aux->func_idx = i;
+ /* Below members will be freed only at prog->aux */
+ func[i]->aux->btf = prog->aux->btf;
+ func[i]->aux->func_info = prog->aux->func_info;
+ func[i]->aux->func_info_cnt = prog->aux->func_info_cnt;
+ func[i]->aux->poke_tab = prog->aux->poke_tab;
+ func[i]->aux->size_poke_tab = prog->aux->size_poke_tab;
+
+ for (j = 0; j < prog->aux->size_poke_tab; j++) {
+ struct bpf_jit_poke_descriptor *poke;
+
+ poke = &prog->aux->poke_tab[j];
+ if (poke->insn_idx < subprog_end &&
+ poke->insn_idx >= subprog_start)
+ poke->aux = func[i]->aux;
+ }
+
+ func[i]->aux->name[0] = 'F';
+ func[i]->aux->stack_depth = env->subprog_info[i].stack_depth;
+ func[i]->jit_requested = 1;
+ func[i]->blinding_requested = prog->blinding_requested;
+ func[i]->aux->kfunc_tab = prog->aux->kfunc_tab;
+ func[i]->aux->kfunc_btf_tab = prog->aux->kfunc_btf_tab;
+ func[i]->aux->linfo = prog->aux->linfo;
+ func[i]->aux->nr_linfo = prog->aux->nr_linfo;
+ func[i]->aux->jited_linfo = prog->aux->jited_linfo;
+ func[i]->aux->linfo_idx = env->subprog_info[i].linfo_idx;
+ num_exentries = 0;
+ insn = func[i]->insnsi;
+ for (j = 0; j < func[i]->len; j++, insn++) {
+ if (BPF_CLASS(insn->code) == BPF_LDX &&
+ (BPF_MODE(insn->code) == BPF_PROBE_MEM ||
+ BPF_MODE(insn->code) == BPF_PROBE_MEMSX))
+ num_exentries++;
+ }
+ func[i]->aux->num_exentries = num_exentries;
+ func[i]->aux->tail_call_reachable = env->subprog_info[i].tail_call_reachable;
+ func[i] = bpf_int_jit_compile(func[i]);
+ if (!func[i]->jited) {
+ err = -ENOTSUPP;
+ goto out_free;
+ }
+ cond_resched();
+ }
+
+ /* at this point all bpf functions were successfully JITed
+ * now populate all bpf_calls with correct addresses and
+ * run last pass of JIT
+ */
+ for (i = 0; i < env->subprog_cnt; i++) {
+ insn = func[i]->insnsi;
+ for (j = 0; j < func[i]->len; j++, insn++) {
+ if (bpf_pseudo_func(insn)) {
+ subprog = insn->off;
+ insn[0].imm = (u32)(long)func[subprog]->bpf_func;
+ insn[1].imm = ((u64)(long)func[subprog]->bpf_func) >> 32;
+ continue;
+ }
+ if (!bpf_pseudo_call(insn))
+ continue;
+ subprog = insn->off;
+ insn->imm = BPF_CALL_IMM(func[subprog]->bpf_func);
+ }
+
+ /* we use the aux data to keep a list of the start addresses
+ * of the JITed images for each function in the program
+ *
+ * for some architectures, such as powerpc64, the imm field
+ * might not be large enough to hold the offset of the start
+ * address of the callee's JITed image from __bpf_call_base
+ *
+ * in such cases, we can lookup the start address of a callee
+ * by using its subprog id, available from the off field of
+ * the call instruction, as an index for this list
+ */
+ func[i]->aux->func = func;
+ func[i]->aux->func_cnt = env->subprog_cnt;
+ }
+ for (i = 0; i < env->subprog_cnt; i++) {
+ old_bpf_func = func[i]->bpf_func;
+ tmp = bpf_int_jit_compile(func[i]);
+ if (tmp != func[i] || func[i]->bpf_func != old_bpf_func) {
+ verbose(env, "JIT doesn't support bpf-to-bpf calls\n");
+ err = -ENOTSUPP;
+ goto out_free;
+ }
+ cond_resched();
+ }
+
+ /* finally lock prog and jit images for all functions and
+ * populate kallsysm. Begin at the first subprogram, since
+ * bpf_prog_load will add the kallsyms for the main program.
+ */
+ for (i = 1; i < env->subprog_cnt; i++) {
+ bpf_prog_lock_ro(func[i]);
+ bpf_prog_kallsyms_add(func[i]);
+ }
+
+ /* Last step: make now unused interpreter insns from main
+ * prog consistent for later dump requests, so they can
+ * later look the same as if they were interpreted only.
+ */
+ for (i = 0, insn = prog->insnsi; i < prog->len; i++, insn++) {
+ if (bpf_pseudo_func(insn)) {
+ insn[0].imm = env->insn_aux_data[i].call_imm;
+ insn[1].imm = insn->off;
+ insn->off = 0;
+ continue;
+ }
+ if (!bpf_pseudo_call(insn))
+ continue;
+ insn->off = env->insn_aux_data[i].call_imm;
+ subprog = find_subprog(env, i + insn->off + 1);
+ insn->imm = subprog;
+ }
+
+ prog->jited = 1;
+ prog->bpf_func = func[0]->bpf_func;
+ prog->jited_len = func[0]->jited_len;
+ prog->aux->extable = func[0]->aux->extable;
+ prog->aux->num_exentries = func[0]->aux->num_exentries;
+ prog->aux->func = func;
+ prog->aux->func_cnt = env->subprog_cnt;
+ bpf_prog_jit_attempt_done(prog);
+ return 0;
+out_free:
+ /* We failed JIT'ing, so at this point we need to unregister poke
+ * descriptors from subprogs, so that kernel is not attempting to
+ * patch it anymore as we're freeing the subprog JIT memory.
+ */
+ for (i = 0; i < prog->aux->size_poke_tab; i++) {
+ map_ptr = prog->aux->poke_tab[i].tail_call.map;
+ map_ptr->ops->map_poke_untrack(map_ptr, prog->aux);
+ }
+ /* At this point we're guaranteed that poke descriptors are not
+ * live anymore. We can just unlink its descriptor table as it's
+ * released with the main prog.
+ */
+ for (i = 0; i < env->subprog_cnt; i++) {
+ if (!func[i])
+ continue;
+ func[i]->aux->poke_tab = NULL;
+ bpf_jit_free(func[i]);
+ }
+ kfree(func);
+out_undo_insn:
+ /* cleanup main prog to be interpreted */
+ prog->jit_requested = 0;
+ prog->blinding_requested = 0;
+ for (i = 0, insn = prog->insnsi; i < prog->len; i++, insn++) {
+ if (!bpf_pseudo_call(insn))
+ continue;
+ insn->off = 0;
+ insn->imm = env->insn_aux_data[i].call_imm;
+ }
+ bpf_prog_jit_attempt_done(prog);
+ return err;
+}
+
+static int fixup_call_args(struct bpf_verifier_env *env)
+{
+#ifndef CONFIG_BPF_JIT_ALWAYS_ON
+ struct bpf_prog *prog = env->prog;
+ struct bpf_insn *insn = prog->insnsi;
+ bool has_kfunc_call = bpf_prog_has_kfunc_call(prog);
+ int i, depth;
+#endif
+ int err = 0;
+
+ if (env->prog->jit_requested &&
+ !bpf_prog_is_offloaded(env->prog->aux)) {
+ err = jit_subprogs(env);
+ if (err == 0)
+ return 0;
+ if (err == -EFAULT)
+ return err;
+ }
+#ifndef CONFIG_BPF_JIT_ALWAYS_ON
+ if (has_kfunc_call) {
+ verbose(env, "calling kernel functions are not allowed in non-JITed programs\n");
+ return -EINVAL;
+ }
+ if (env->subprog_cnt > 1 && env->prog->aux->tail_call_reachable) {
+ /* When JIT fails the progs with bpf2bpf calls and tail_calls
+ * have to be rejected, since interpreter doesn't support them yet.
+ */
+ verbose(env, "tail_calls are not allowed in non-JITed programs with bpf-to-bpf calls\n");
+ return -EINVAL;
+ }
+ for (i = 0; i < prog->len; i++, insn++) {
+ if (bpf_pseudo_func(insn)) {
+ /* When JIT fails the progs with callback calls
+ * have to be rejected, since interpreter doesn't support them yet.
+ */
+ verbose(env, "callbacks are not allowed in non-JITed programs\n");
+ return -EINVAL;
+ }
+
+ if (!bpf_pseudo_call(insn))
+ continue;
+ depth = get_callee_stack_depth(env, insn, i);
+ if (depth < 0)
+ return depth;
+ bpf_patch_call_args(insn, depth);
+ }
+ err = 0;
+#endif
+ return err;
+}
+
+/* replace a generic kfunc with a specialized version if necessary */
+static void specialize_kfunc(struct bpf_verifier_env *env,
+ u32 func_id, u16 offset, unsigned long *addr)
+{
+ struct bpf_prog *prog = env->prog;
+ bool seen_direct_write;
+ void *xdp_kfunc;
+ bool is_rdonly;
+
+ if (bpf_dev_bound_kfunc_id(func_id)) {
+ xdp_kfunc = bpf_dev_bound_resolve_kfunc(prog, func_id);
+ if (xdp_kfunc) {
+ *addr = (unsigned long)xdp_kfunc;
+ return;
+ }
+ /* fallback to default kfunc when not supported by netdev */
+ }
+
+ if (offset)
+ return;
+
+ if (func_id == special_kfunc_list[KF_bpf_dynptr_from_skb]) {
+ seen_direct_write = env->seen_direct_write;
+ is_rdonly = !may_access_direct_pkt_data(env, NULL, BPF_WRITE);
+
+ if (is_rdonly)
+ *addr = (unsigned long)bpf_dynptr_from_skb_rdonly;
+
+ /* restore env->seen_direct_write to its original value, since
+ * may_access_direct_pkt_data mutates it
+ */
+ env->seen_direct_write = seen_direct_write;
+ }
+}
+
+static void __fixup_collection_insert_kfunc(struct bpf_insn_aux_data *insn_aux,
+ u16 struct_meta_reg,
+ u16 node_offset_reg,
+ struct bpf_insn *insn,
+ struct bpf_insn *insn_buf,
+ int *cnt)
+{
+ struct btf_struct_meta *kptr_struct_meta = insn_aux->kptr_struct_meta;
+ struct bpf_insn addr[2] = { BPF_LD_IMM64(struct_meta_reg, (long)kptr_struct_meta) };
+
+ insn_buf[0] = addr[0];
+ insn_buf[1] = addr[1];
+ insn_buf[2] = BPF_MOV64_IMM(node_offset_reg, insn_aux->insert_off);
+ insn_buf[3] = *insn;
+ *cnt = 4;
+}
+
+static int fixup_kfunc_call(struct bpf_verifier_env *env, struct bpf_insn *insn,
+ struct bpf_insn *insn_buf, int insn_idx, int *cnt)
+{
+ const struct bpf_kfunc_desc *desc;
+
+ if (!insn->imm) {
+ verbose(env, "invalid kernel function call not eliminated in verifier pass\n");
+ return -EINVAL;
+ }
+
+ *cnt = 0;
+
+ /* insn->imm has the btf func_id. Replace it with an offset relative to
+ * __bpf_call_base, unless the JIT needs to call functions that are
+ * further than 32 bits away (bpf_jit_supports_far_kfunc_call()).
+ */
+ desc = find_kfunc_desc(env->prog, insn->imm, insn->off);
+ if (!desc) {
+ verbose(env, "verifier internal error: kernel function descriptor not found for func_id %u\n",
+ insn->imm);
+ return -EFAULT;
+ }
+
+ if (!bpf_jit_supports_far_kfunc_call())
+ insn->imm = BPF_CALL_IMM(desc->addr);
+ if (insn->off)
+ return 0;
+ if (desc->func_id == special_kfunc_list[KF_bpf_obj_new_impl]) {
+ struct btf_struct_meta *kptr_struct_meta = env->insn_aux_data[insn_idx].kptr_struct_meta;
+ struct bpf_insn addr[2] = { BPF_LD_IMM64(BPF_REG_2, (long)kptr_struct_meta) };
+ u64 obj_new_size = env->insn_aux_data[insn_idx].obj_new_size;
+
+ insn_buf[0] = BPF_MOV64_IMM(BPF_REG_1, obj_new_size);
+ insn_buf[1] = addr[0];
+ insn_buf[2] = addr[1];
+ insn_buf[3] = *insn;
+ *cnt = 4;
+ } else if (desc->func_id == special_kfunc_list[KF_bpf_obj_drop_impl] ||
+ desc->func_id == special_kfunc_list[KF_bpf_refcount_acquire_impl]) {
+ struct btf_struct_meta *kptr_struct_meta = env->insn_aux_data[insn_idx].kptr_struct_meta;
+ struct bpf_insn addr[2] = { BPF_LD_IMM64(BPF_REG_2, (long)kptr_struct_meta) };
+
+ if (desc->func_id == special_kfunc_list[KF_bpf_refcount_acquire_impl] &&
+ !kptr_struct_meta) {
+ verbose(env, "verifier internal error: kptr_struct_meta expected at insn_idx %d\n",
+ insn_idx);
+ return -EFAULT;
+ }
+
+ insn_buf[0] = addr[0];
+ insn_buf[1] = addr[1];
+ insn_buf[2] = *insn;
+ *cnt = 3;
+ } else if (desc->func_id == special_kfunc_list[KF_bpf_list_push_back_impl] ||
+ desc->func_id == special_kfunc_list[KF_bpf_list_push_front_impl] ||
+ desc->func_id == special_kfunc_list[KF_bpf_rbtree_add_impl]) {
+ struct btf_struct_meta *kptr_struct_meta = env->insn_aux_data[insn_idx].kptr_struct_meta;
+ int struct_meta_reg = BPF_REG_3;
+ int node_offset_reg = BPF_REG_4;
+
+ /* rbtree_add has extra 'less' arg, so args-to-fixup are in diff regs */
+ if (desc->func_id == special_kfunc_list[KF_bpf_rbtree_add_impl]) {
+ struct_meta_reg = BPF_REG_4;
+ node_offset_reg = BPF_REG_5;
+ }
+
+ if (!kptr_struct_meta) {
+ verbose(env, "verifier internal error: kptr_struct_meta expected at insn_idx %d\n",
+ insn_idx);
+ return -EFAULT;
+ }
+
+ __fixup_collection_insert_kfunc(&env->insn_aux_data[insn_idx], struct_meta_reg,
+ node_offset_reg, insn, insn_buf, cnt);
+ } else if (desc->func_id == special_kfunc_list[KF_bpf_cast_to_kern_ctx] ||
+ desc->func_id == special_kfunc_list[KF_bpf_rdonly_cast]) {
+ insn_buf[0] = BPF_MOV64_REG(BPF_REG_0, BPF_REG_1);
+ *cnt = 1;
+ }
+ return 0;
+}
+
+/* Do various post-verification rewrites in a single program pass.
+ * These rewrites simplify JIT and interpreter implementations.
+ */
+static int do_misc_fixups(struct bpf_verifier_env *env)
+{
+ struct bpf_prog *prog = env->prog;
+ enum bpf_attach_type eatype = prog->expected_attach_type;
+ enum bpf_prog_type prog_type = resolve_prog_type(prog);
+ struct bpf_insn *insn = prog->insnsi;
+ const struct bpf_func_proto *fn;
+ const int insn_cnt = prog->len;
+ const struct bpf_map_ops *ops;
+ struct bpf_insn_aux_data *aux;
+ struct bpf_insn insn_buf[16];
+ struct bpf_prog *new_prog;
+ struct bpf_map *map_ptr;
+ int i, ret, cnt, delta = 0;
+
+ for (i = 0; i < insn_cnt; i++, insn++) {
+ /* Make divide-by-zero exceptions impossible. */
+ if (insn->code == (BPF_ALU64 | BPF_MOD | BPF_X) ||
+ insn->code == (BPF_ALU64 | BPF_DIV | BPF_X) ||
+ insn->code == (BPF_ALU | BPF_MOD | BPF_X) ||
+ insn->code == (BPF_ALU | BPF_DIV | BPF_X)) {
+ bool is64 = BPF_CLASS(insn->code) == BPF_ALU64;
+ bool isdiv = BPF_OP(insn->code) == BPF_DIV;
+ struct bpf_insn *patchlet;
+ struct bpf_insn chk_and_div[] = {
+ /* [R,W]x div 0 -> 0 */
+ BPF_RAW_INSN((is64 ? BPF_JMP : BPF_JMP32) |
+ BPF_JNE | BPF_K, insn->src_reg,
+ 0, 2, 0),
+ BPF_ALU32_REG(BPF_XOR, insn->dst_reg, insn->dst_reg),
+ BPF_JMP_IMM(BPF_JA, 0, 0, 1),
+ *insn,
+ };
+ struct bpf_insn chk_and_mod[] = {
+ /* [R,W]x mod 0 -> [R,W]x */
+ BPF_RAW_INSN((is64 ? BPF_JMP : BPF_JMP32) |
+ BPF_JEQ | BPF_K, insn->src_reg,
+ 0, 1 + (is64 ? 0 : 1), 0),
+ *insn,
+ BPF_JMP_IMM(BPF_JA, 0, 0, 1),
+ BPF_MOV32_REG(insn->dst_reg, insn->dst_reg),
+ };
+
+ patchlet = isdiv ? chk_and_div : chk_and_mod;
+ cnt = isdiv ? ARRAY_SIZE(chk_and_div) :
+ ARRAY_SIZE(chk_and_mod) - (is64 ? 2 : 0);
+
+ new_prog = bpf_patch_insn_data(env, i + delta, patchlet, cnt);
+ if (!new_prog)
+ return -ENOMEM;
+
+ delta += cnt - 1;
+ env->prog = prog = new_prog;
+ insn = new_prog->insnsi + i + delta;
+ continue;
+ }
+
+ /* Implement LD_ABS and LD_IND with a rewrite, if supported by the program type. */
+ if (BPF_CLASS(insn->code) == BPF_LD &&
+ (BPF_MODE(insn->code) == BPF_ABS ||
+ BPF_MODE(insn->code) == BPF_IND)) {
+ cnt = env->ops->gen_ld_abs(insn, insn_buf);
+ if (cnt == 0 || cnt >= ARRAY_SIZE(insn_buf)) {
+ verbose(env, "bpf verifier is misconfigured\n");
+ return -EINVAL;
+ }
+
+ new_prog = bpf_patch_insn_data(env, i + delta, insn_buf, cnt);
+ if (!new_prog)
+ return -ENOMEM;
+
+ delta += cnt - 1;
+ env->prog = prog = new_prog;
+ insn = new_prog->insnsi + i + delta;
+ continue;
+ }
+
+ /* Rewrite pointer arithmetic to mitigate speculation attacks. */
+ if (insn->code == (BPF_ALU64 | BPF_ADD | BPF_X) ||
+ insn->code == (BPF_ALU64 | BPF_SUB | BPF_X)) {
+ const u8 code_add = BPF_ALU64 | BPF_ADD | BPF_X;
+ const u8 code_sub = BPF_ALU64 | BPF_SUB | BPF_X;
+ struct bpf_insn *patch = &insn_buf[0];
+ bool issrc, isneg, isimm;
+ u32 off_reg;
+
+ aux = &env->insn_aux_data[i + delta];
+ if (!aux->alu_state ||
+ aux->alu_state == BPF_ALU_NON_POINTER)
+ continue;
+
+ isneg = aux->alu_state & BPF_ALU_NEG_VALUE;
+ issrc = (aux->alu_state & BPF_ALU_SANITIZE) ==
+ BPF_ALU_SANITIZE_SRC;
+ isimm = aux->alu_state & BPF_ALU_IMMEDIATE;
+
+ off_reg = issrc ? insn->src_reg : insn->dst_reg;
+ if (isimm) {
+ *patch++ = BPF_MOV32_IMM(BPF_REG_AX, aux->alu_limit);
+ } else {
+ if (isneg)
+ *patch++ = BPF_ALU64_IMM(BPF_MUL, off_reg, -1);
+ *patch++ = BPF_MOV32_IMM(BPF_REG_AX, aux->alu_limit);
+ *patch++ = BPF_ALU64_REG(BPF_SUB, BPF_REG_AX, off_reg);
+ *patch++ = BPF_ALU64_REG(BPF_OR, BPF_REG_AX, off_reg);
+ *patch++ = BPF_ALU64_IMM(BPF_NEG, BPF_REG_AX, 0);
+ *patch++ = BPF_ALU64_IMM(BPF_ARSH, BPF_REG_AX, 63);
+ *patch++ = BPF_ALU64_REG(BPF_AND, BPF_REG_AX, off_reg);
+ }
+ if (!issrc)
+ *patch++ = BPF_MOV64_REG(insn->dst_reg, insn->src_reg);
+ insn->src_reg = BPF_REG_AX;
+ if (isneg)
+ insn->code = insn->code == code_add ?
+ code_sub : code_add;
+ *patch++ = *insn;
+ if (issrc && isneg && !isimm)
+ *patch++ = BPF_ALU64_IMM(BPF_MUL, off_reg, -1);
+ cnt = patch - insn_buf;
+
+ new_prog = bpf_patch_insn_data(env, i + delta, insn_buf, cnt);
+ if (!new_prog)
+ return -ENOMEM;
+
+ delta += cnt - 1;
+ env->prog = prog = new_prog;
+ insn = new_prog->insnsi + i + delta;
+ continue;
+ }
+
+ if (insn->code != (BPF_JMP | BPF_CALL))
+ continue;
+ if (insn->src_reg == BPF_PSEUDO_CALL)
+ continue;
+ if (insn->src_reg == BPF_PSEUDO_KFUNC_CALL) {
+ ret = fixup_kfunc_call(env, insn, insn_buf, i + delta, &cnt);
+ if (ret)
+ return ret;
+ if (cnt == 0)
+ continue;
+
+ new_prog = bpf_patch_insn_data(env, i + delta, insn_buf, cnt);
+ if (!new_prog)
+ return -ENOMEM;
+
+ delta += cnt - 1;
+ env->prog = prog = new_prog;
+ insn = new_prog->insnsi + i + delta;
+ continue;
+ }
+
+ if (insn->imm == BPF_FUNC_get_route_realm)
+ prog->dst_needed = 1;
+ if (insn->imm == BPF_FUNC_get_prandom_u32)
+ bpf_user_rnd_init_once();
+ if (insn->imm == BPF_FUNC_override_return)
+ prog->kprobe_override = 1;
+ if (insn->imm == BPF_FUNC_tail_call) {
+ /* If we tail call into other programs, we
+ * cannot make any assumptions since they can
+ * be replaced dynamically during runtime in
+ * the program array.
+ */
+ prog->cb_access = 1;
+ if (!allow_tail_call_in_subprogs(env))
+ prog->aux->stack_depth = MAX_BPF_STACK;
+ prog->aux->max_pkt_offset = MAX_PACKET_OFF;
+
+ /* mark bpf_tail_call as different opcode to avoid
+ * conditional branch in the interpreter for every normal
+ * call and to prevent accidental JITing by JIT compiler
+ * that doesn't support bpf_tail_call yet
+ */
+ insn->imm = 0;
+ insn->code = BPF_JMP | BPF_TAIL_CALL;
+
+ aux = &env->insn_aux_data[i + delta];
+ if (env->bpf_capable && !prog->blinding_requested &&
+ prog->jit_requested &&
+ !bpf_map_key_poisoned(aux) &&
+ !bpf_map_ptr_poisoned(aux) &&
+ !bpf_map_ptr_unpriv(aux)) {
+ struct bpf_jit_poke_descriptor desc = {
+ .reason = BPF_POKE_REASON_TAIL_CALL,
+ .tail_call.map = BPF_MAP_PTR(aux->map_ptr_state),
+ .tail_call.key = bpf_map_key_immediate(aux),
+ .insn_idx = i + delta,
+ };
+
+ ret = bpf_jit_add_poke_descriptor(prog, &desc);
+ if (ret < 0) {
+ verbose(env, "adding tail call poke descriptor failed\n");
+ return ret;
+ }
+
+ insn->imm = ret + 1;
+ continue;
+ }
+
+ if (!bpf_map_ptr_unpriv(aux))
+ continue;
+
+ /* instead of changing every JIT dealing with tail_call
+ * emit two extra insns:
+ * if (index >= max_entries) goto out;
+ * index &= array->index_mask;
+ * to avoid out-of-bounds cpu speculation
+ */
+ if (bpf_map_ptr_poisoned(aux)) {
+ verbose(env, "tail_call abusing map_ptr\n");
+ return -EINVAL;
+ }
+
+ map_ptr = BPF_MAP_PTR(aux->map_ptr_state);
+ insn_buf[0] = BPF_JMP_IMM(BPF_JGE, BPF_REG_3,
+ map_ptr->max_entries, 2);
+ insn_buf[1] = BPF_ALU32_IMM(BPF_AND, BPF_REG_3,
+ container_of(map_ptr,
+ struct bpf_array,
+ map)->index_mask);
+ insn_buf[2] = *insn;
+ cnt = 3;
+ new_prog = bpf_patch_insn_data(env, i + delta, insn_buf, cnt);
+ if (!new_prog)
+ return -ENOMEM;
+
+ delta += cnt - 1;
+ env->prog = prog = new_prog;
+ insn = new_prog->insnsi + i + delta;
+ continue;
+ }
+
+ if (insn->imm == BPF_FUNC_timer_set_callback) {
+ /* The verifier will process callback_fn as many times as necessary
+ * with different maps and the register states prepared by
+ * set_timer_callback_state will be accurate.
+ *
+ * The following use case is valid:
+ * map1 is shared by prog1, prog2, prog3.
+ * prog1 calls bpf_timer_init for some map1 elements
+ * prog2 calls bpf_timer_set_callback for some map1 elements.
+ * Those that were not bpf_timer_init-ed will return -EINVAL.
+ * prog3 calls bpf_timer_start for some map1 elements.
+ * Those that were not both bpf_timer_init-ed and
+ * bpf_timer_set_callback-ed will return -EINVAL.
+ */
+ struct bpf_insn ld_addrs[2] = {
+ BPF_LD_IMM64(BPF_REG_3, (long)prog->aux),
+ };
+
+ insn_buf[0] = ld_addrs[0];
+ insn_buf[1] = ld_addrs[1];
+ insn_buf[2] = *insn;
+ cnt = 3;
+
+ new_prog = bpf_patch_insn_data(env, i + delta, insn_buf, cnt);
+ if (!new_prog)
+ return -ENOMEM;
+
+ delta += cnt - 1;
+ env->prog = prog = new_prog;
+ insn = new_prog->insnsi + i + delta;
+ goto patch_call_imm;
+ }
+
+ if (is_storage_get_function(insn->imm)) {
+ if (!env->prog->aux->sleepable ||
+ env->insn_aux_data[i + delta].storage_get_func_atomic)
+ insn_buf[0] = BPF_MOV64_IMM(BPF_REG_5, (__force __s32)GFP_ATOMIC);
+ else
+ insn_buf[0] = BPF_MOV64_IMM(BPF_REG_5, (__force __s32)GFP_KERNEL);
+ insn_buf[1] = *insn;
+ cnt = 2;
+
+ new_prog = bpf_patch_insn_data(env, i + delta, insn_buf, cnt);
+ if (!new_prog)
+ return -ENOMEM;
+
+ delta += cnt - 1;
+ env->prog = prog = new_prog;
+ insn = new_prog->insnsi + i + delta;
+ goto patch_call_imm;
+ }
+
+ /* BPF_EMIT_CALL() assumptions in some of the map_gen_lookup
+ * and other inlining handlers are currently limited to 64 bit
+ * only.
+ */
+ if (prog->jit_requested && BITS_PER_LONG == 64 &&
+ (insn->imm == BPF_FUNC_map_lookup_elem ||
+ insn->imm == BPF_FUNC_map_update_elem ||
+ insn->imm == BPF_FUNC_map_delete_elem ||
+ insn->imm == BPF_FUNC_map_push_elem ||
+ insn->imm == BPF_FUNC_map_pop_elem ||
+ insn->imm == BPF_FUNC_map_peek_elem ||
+ insn->imm == BPF_FUNC_redirect_map ||
+ insn->imm == BPF_FUNC_for_each_map_elem ||
+ insn->imm == BPF_FUNC_map_lookup_percpu_elem)) {
+ aux = &env->insn_aux_data[i + delta];
+ if (bpf_map_ptr_poisoned(aux))
+ goto patch_call_imm;
+
+ map_ptr = BPF_MAP_PTR(aux->map_ptr_state);
+ ops = map_ptr->ops;
+ if (insn->imm == BPF_FUNC_map_lookup_elem &&
+ ops->map_gen_lookup) {
+ cnt = ops->map_gen_lookup(map_ptr, insn_buf);
+ if (cnt == -EOPNOTSUPP)
+ goto patch_map_ops_generic;
+ if (cnt <= 0 || cnt >= ARRAY_SIZE(insn_buf)) {
+ verbose(env, "bpf verifier is misconfigured\n");
+ return -EINVAL;
+ }
+
+ new_prog = bpf_patch_insn_data(env, i + delta,
+ insn_buf, cnt);
+ if (!new_prog)
+ return -ENOMEM;
+
+ delta += cnt - 1;
+ env->prog = prog = new_prog;
+ insn = new_prog->insnsi + i + delta;
+ continue;
+ }
+
+ BUILD_BUG_ON(!__same_type(ops->map_lookup_elem,
+ (void *(*)(struct bpf_map *map, void *key))NULL));
+ BUILD_BUG_ON(!__same_type(ops->map_delete_elem,
+ (long (*)(struct bpf_map *map, void *key))NULL));
+ BUILD_BUG_ON(!__same_type(ops->map_update_elem,
+ (long (*)(struct bpf_map *map, void *key, void *value,
+ u64 flags))NULL));
+ BUILD_BUG_ON(!__same_type(ops->map_push_elem,
+ (long (*)(struct bpf_map *map, void *value,
+ u64 flags))NULL));
+ BUILD_BUG_ON(!__same_type(ops->map_pop_elem,
+ (long (*)(struct bpf_map *map, void *value))NULL));
+ BUILD_BUG_ON(!__same_type(ops->map_peek_elem,
+ (long (*)(struct bpf_map *map, void *value))NULL));
+ BUILD_BUG_ON(!__same_type(ops->map_redirect,
+ (long (*)(struct bpf_map *map, u64 index, u64 flags))NULL));
+ BUILD_BUG_ON(!__same_type(ops->map_for_each_callback,
+ (long (*)(struct bpf_map *map,
+ bpf_callback_t callback_fn,
+ void *callback_ctx,
+ u64 flags))NULL));
+ BUILD_BUG_ON(!__same_type(ops->map_lookup_percpu_elem,
+ (void *(*)(struct bpf_map *map, void *key, u32 cpu))NULL));
+
+patch_map_ops_generic:
+ switch (insn->imm) {
+ case BPF_FUNC_map_lookup_elem:
+ insn->imm = BPF_CALL_IMM(ops->map_lookup_elem);
+ continue;
+ case BPF_FUNC_map_update_elem:
+ insn->imm = BPF_CALL_IMM(ops->map_update_elem);
+ continue;
+ case BPF_FUNC_map_delete_elem:
+ insn->imm = BPF_CALL_IMM(ops->map_delete_elem);
+ continue;
+ case BPF_FUNC_map_push_elem:
+ insn->imm = BPF_CALL_IMM(ops->map_push_elem);
+ continue;
+ case BPF_FUNC_map_pop_elem:
+ insn->imm = BPF_CALL_IMM(ops->map_pop_elem);
+ continue;
+ case BPF_FUNC_map_peek_elem:
+ insn->imm = BPF_CALL_IMM(ops->map_peek_elem);
+ continue;
+ case BPF_FUNC_redirect_map:
+ insn->imm = BPF_CALL_IMM(ops->map_redirect);
+ continue;
+ case BPF_FUNC_for_each_map_elem:
+ insn->imm = BPF_CALL_IMM(ops->map_for_each_callback);
+ continue;
+ case BPF_FUNC_map_lookup_percpu_elem:
+ insn->imm = BPF_CALL_IMM(ops->map_lookup_percpu_elem);
+ continue;
+ }
+
+ goto patch_call_imm;
+ }
+
+ /* Implement bpf_jiffies64 inline. */
+ if (prog->jit_requested && BITS_PER_LONG == 64 &&
+ insn->imm == BPF_FUNC_jiffies64) {
+ struct bpf_insn ld_jiffies_addr[2] = {
+ BPF_LD_IMM64(BPF_REG_0,
+ (unsigned long)&jiffies),
+ };
+
+ insn_buf[0] = ld_jiffies_addr[0];
+ insn_buf[1] = ld_jiffies_addr[1];
+ insn_buf[2] = BPF_LDX_MEM(BPF_DW, BPF_REG_0,
+ BPF_REG_0, 0);
+ cnt = 3;
+
+ new_prog = bpf_patch_insn_data(env, i + delta, insn_buf,
+ cnt);
+ if (!new_prog)
+ return -ENOMEM;
+
+ delta += cnt - 1;
+ env->prog = prog = new_prog;
+ insn = new_prog->insnsi + i + delta;
+ continue;
+ }
+
+ /* Implement bpf_get_func_arg inline. */
+ if (prog_type == BPF_PROG_TYPE_TRACING &&
+ insn->imm == BPF_FUNC_get_func_arg) {
+ /* Load nr_args from ctx - 8 */
+ insn_buf[0] = BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_1, -8);
+ insn_buf[1] = BPF_JMP32_REG(BPF_JGE, BPF_REG_2, BPF_REG_0, 6);
+ insn_buf[2] = BPF_ALU64_IMM(BPF_LSH, BPF_REG_2, 3);
+ insn_buf[3] = BPF_ALU64_REG(BPF_ADD, BPF_REG_2, BPF_REG_1);
+ insn_buf[4] = BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_2, 0);
+ insn_buf[5] = BPF_STX_MEM(BPF_DW, BPF_REG_3, BPF_REG_0, 0);
+ insn_buf[6] = BPF_MOV64_IMM(BPF_REG_0, 0);
+ insn_buf[7] = BPF_JMP_A(1);
+ insn_buf[8] = BPF_MOV64_IMM(BPF_REG_0, -EINVAL);
+ cnt = 9;
+
+ new_prog = bpf_patch_insn_data(env, i + delta, insn_buf, cnt);
+ if (!new_prog)
+ return -ENOMEM;
+
+ delta += cnt - 1;
+ env->prog = prog = new_prog;
+ insn = new_prog->insnsi + i + delta;
+ continue;
+ }
+
+ /* Implement bpf_get_func_ret inline. */
+ if (prog_type == BPF_PROG_TYPE_TRACING &&
+ insn->imm == BPF_FUNC_get_func_ret) {
+ if (eatype == BPF_TRACE_FEXIT ||
+ eatype == BPF_MODIFY_RETURN) {
+ /* Load nr_args from ctx - 8 */
+ insn_buf[0] = BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_1, -8);
+ insn_buf[1] = BPF_ALU64_IMM(BPF_LSH, BPF_REG_0, 3);
+ insn_buf[2] = BPF_ALU64_REG(BPF_ADD, BPF_REG_0, BPF_REG_1);
+ insn_buf[3] = BPF_LDX_MEM(BPF_DW, BPF_REG_3, BPF_REG_0, 0);
+ insn_buf[4] = BPF_STX_MEM(BPF_DW, BPF_REG_2, BPF_REG_3, 0);
+ insn_buf[5] = BPF_MOV64_IMM(BPF_REG_0, 0);
+ cnt = 6;
+ } else {
+ insn_buf[0] = BPF_MOV64_IMM(BPF_REG_0, -EOPNOTSUPP);
+ cnt = 1;
+ }
+
+ new_prog = bpf_patch_insn_data(env, i + delta, insn_buf, cnt);
+ if (!new_prog)
+ return -ENOMEM;
+
+ delta += cnt - 1;
+ env->prog = prog = new_prog;
+ insn = new_prog->insnsi + i + delta;
+ continue;
+ }
+
+ /* Implement get_func_arg_cnt inline. */
+ if (prog_type == BPF_PROG_TYPE_TRACING &&
+ insn->imm == BPF_FUNC_get_func_arg_cnt) {
+ /* Load nr_args from ctx - 8 */
+ insn_buf[0] = BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_1, -8);
+
+ new_prog = bpf_patch_insn_data(env, i + delta, insn_buf, 1);
+ if (!new_prog)
+ return -ENOMEM;
+
+ env->prog = prog = new_prog;
+ insn = new_prog->insnsi + i + delta;
+ continue;
+ }
+
+ /* Implement bpf_get_func_ip inline. */
+ if (prog_type == BPF_PROG_TYPE_TRACING &&
+ insn->imm == BPF_FUNC_get_func_ip) {
+ /* Load IP address from ctx - 16 */
+ insn_buf[0] = BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_1, -16);
+
+ new_prog = bpf_patch_insn_data(env, i + delta, insn_buf, 1);
+ if (!new_prog)
+ return -ENOMEM;
+
+ env->prog = prog = new_prog;
+ insn = new_prog->insnsi + i + delta;
+ continue;
+ }
+
+patch_call_imm:
+ fn = env->ops->get_func_proto(insn->imm, env->prog);
+ /* all functions that have prototype and verifier allowed
+ * programs to call them, must be real in-kernel functions
+ */
+ if (!fn->func) {
+ verbose(env,
+ "kernel subsystem misconfigured func %s#%d\n",
+ func_id_name(insn->imm), insn->imm);
+ return -EFAULT;
+ }
+ insn->imm = fn->func - __bpf_call_base;
+ }
+
+ /* Since poke tab is now finalized, publish aux to tracker. */
+ for (i = 0; i < prog->aux->size_poke_tab; i++) {
+ map_ptr = prog->aux->poke_tab[i].tail_call.map;
+ if (!map_ptr->ops->map_poke_track ||
+ !map_ptr->ops->map_poke_untrack ||
+ !map_ptr->ops->map_poke_run) {
+ verbose(env, "bpf verifier is misconfigured\n");
+ return -EINVAL;
+ }
+
+ ret = map_ptr->ops->map_poke_track(map_ptr, prog->aux);
+ if (ret < 0) {
+ verbose(env, "tracking tail call prog failed\n");
+ return ret;
+ }
+ }
+
+ sort_kfunc_descs_by_imm_off(env->prog);
+
+ return 0;
+}
+
+static struct bpf_prog *inline_bpf_loop(struct bpf_verifier_env *env,
+ int position,
+ s32 stack_base,
+ u32 callback_subprogno,
+ u32 *cnt)
+{
+ s32 r6_offset = stack_base + 0 * BPF_REG_SIZE;
+ s32 r7_offset = stack_base + 1 * BPF_REG_SIZE;
+ s32 r8_offset = stack_base + 2 * BPF_REG_SIZE;
+ int reg_loop_max = BPF_REG_6;
+ int reg_loop_cnt = BPF_REG_7;
+ int reg_loop_ctx = BPF_REG_8;
+
+ struct bpf_prog *new_prog;
+ u32 callback_start;
+ u32 call_insn_offset;
+ s32 callback_offset;
+
+ /* This represents an inlined version of bpf_iter.c:bpf_loop,
+ * be careful to modify this code in sync.
+ */
+ struct bpf_insn insn_buf[] = {
+ /* Return error and jump to the end of the patch if
+ * expected number of iterations is too big.
+ */
+ BPF_JMP_IMM(BPF_JLE, BPF_REG_1, BPF_MAX_LOOPS, 2),
+ BPF_MOV32_IMM(BPF_REG_0, -E2BIG),
+ BPF_JMP_IMM(BPF_JA, 0, 0, 16),
+ /* spill R6, R7, R8 to use these as loop vars */
+ BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_6, r6_offset),
+ BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_7, r7_offset),
+ BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_8, r8_offset),
+ /* initialize loop vars */
+ BPF_MOV64_REG(reg_loop_max, BPF_REG_1),
+ BPF_MOV32_IMM(reg_loop_cnt, 0),
+ BPF_MOV64_REG(reg_loop_ctx, BPF_REG_3),
+ /* loop header,
+ * if reg_loop_cnt >= reg_loop_max skip the loop body
+ */
+ BPF_JMP_REG(BPF_JGE, reg_loop_cnt, reg_loop_max, 5),
+ /* callback call,
+ * correct callback offset would be set after patching
+ */
+ BPF_MOV64_REG(BPF_REG_1, reg_loop_cnt),
+ BPF_MOV64_REG(BPF_REG_2, reg_loop_ctx),
+ BPF_CALL_REL(0),
+ /* increment loop counter */
+ BPF_ALU64_IMM(BPF_ADD, reg_loop_cnt, 1),
+ /* jump to loop header if callback returned 0 */
+ BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, -6),
+ /* return value of bpf_loop,
+ * set R0 to the number of iterations
+ */
+ BPF_MOV64_REG(BPF_REG_0, reg_loop_cnt),
+ /* restore original values of R6, R7, R8 */
+ BPF_LDX_MEM(BPF_DW, BPF_REG_6, BPF_REG_10, r6_offset),
+ BPF_LDX_MEM(BPF_DW, BPF_REG_7, BPF_REG_10, r7_offset),
+ BPF_LDX_MEM(BPF_DW, BPF_REG_8, BPF_REG_10, r8_offset),
+ };
+
+ *cnt = ARRAY_SIZE(insn_buf);
+ new_prog = bpf_patch_insn_data(env, position, insn_buf, *cnt);
+ if (!new_prog)
+ return new_prog;
+
+ /* callback start is known only after patching */
+ callback_start = env->subprog_info[callback_subprogno].start;
+ /* Note: insn_buf[12] is an offset of BPF_CALL_REL instruction */
+ call_insn_offset = position + 12;
+ callback_offset = callback_start - call_insn_offset - 1;
+ new_prog->insnsi[call_insn_offset].imm = callback_offset;
+
+ return new_prog;
+}
+
+static bool is_bpf_loop_call(struct bpf_insn *insn)
+{
+ return insn->code == (BPF_JMP | BPF_CALL) &&
+ insn->src_reg == 0 &&
+ insn->imm == BPF_FUNC_loop;
+}
+
+/* For all sub-programs in the program (including main) check
+ * insn_aux_data to see if there are bpf_loop calls that require
+ * inlining. If such calls are found the calls are replaced with a
+ * sequence of instructions produced by `inline_bpf_loop` function and
+ * subprog stack_depth is increased by the size of 3 registers.
+ * This stack space is used to spill values of the R6, R7, R8. These
+ * registers are used to store the loop bound, counter and context
+ * variables.
+ */
+static int optimize_bpf_loop(struct bpf_verifier_env *env)
+{
+ struct bpf_subprog_info *subprogs = env->subprog_info;
+ int i, cur_subprog = 0, cnt, delta = 0;
+ struct bpf_insn *insn = env->prog->insnsi;
+ int insn_cnt = env->prog->len;
+ u16 stack_depth = subprogs[cur_subprog].stack_depth;
+ u16 stack_depth_roundup = round_up(stack_depth, 8) - stack_depth;
+ u16 stack_depth_extra = 0;
+
+ for (i = 0; i < insn_cnt; i++, insn++) {
+ struct bpf_loop_inline_state *inline_state =
+ &env->insn_aux_data[i + delta].loop_inline_state;
+
+ if (is_bpf_loop_call(insn) && inline_state->fit_for_inline) {
+ struct bpf_prog *new_prog;
+
+ stack_depth_extra = BPF_REG_SIZE * 3 + stack_depth_roundup;
+ new_prog = inline_bpf_loop(env,
+ i + delta,
+ -(stack_depth + stack_depth_extra),
+ inline_state->callback_subprogno,
+ &cnt);
+ if (!new_prog)
+ return -ENOMEM;
+
+ delta += cnt - 1;
+ env->prog = new_prog;
+ insn = new_prog->insnsi + i + delta;
+ }
+
+ if (subprogs[cur_subprog + 1].start == i + delta + 1) {
+ subprogs[cur_subprog].stack_depth += stack_depth_extra;
+ cur_subprog++;
+ stack_depth = subprogs[cur_subprog].stack_depth;
+ stack_depth_roundup = round_up(stack_depth, 8) - stack_depth;
+ stack_depth_extra = 0;
+ }
+ }
+
+ env->prog->aux->stack_depth = env->subprog_info[0].stack_depth;
+
+ return 0;
+}
+
+static void free_states(struct bpf_verifier_env *env)
+{
+ struct bpf_verifier_state_list *sl, *sln;
+ int i;
+
+ sl = env->free_list;
+ while (sl) {
+ sln = sl->next;
+ free_verifier_state(&sl->state, false);
+ kfree(sl);
+ sl = sln;
+ }
+ env->free_list = NULL;
+
+ if (!env->explored_states)
+ return;
+
+ for (i = 0; i < state_htab_size(env); i++) {
+ sl = env->explored_states[i];
+
+ while (sl) {
+ sln = sl->next;
+ free_verifier_state(&sl->state, false);
+ kfree(sl);
+ sl = sln;
+ }
+ env->explored_states[i] = NULL;
+ }
+}
+
+static int do_check_common(struct bpf_verifier_env *env, int subprog)
+{
+ bool pop_log = !(env->log.level & BPF_LOG_LEVEL2);
+ struct bpf_verifier_state *state;
+ struct bpf_reg_state *regs;
+ int ret, i;
+
+ env->prev_linfo = NULL;
+ env->pass_cnt++;
+
+ state = kzalloc(sizeof(struct bpf_verifier_state), GFP_KERNEL);
+ if (!state)
+ return -ENOMEM;
+ state->curframe = 0;
+ state->speculative = false;
+ state->branches = 1;
+ state->frame[0] = kzalloc(sizeof(struct bpf_func_state), GFP_KERNEL);
+ if (!state->frame[0]) {
+ kfree(state);
+ return -ENOMEM;
+ }
+ env->cur_state = state;
+ init_func_state(env, state->frame[0],
+ BPF_MAIN_FUNC /* callsite */,
+ 0 /* frameno */,
+ subprog);
+ state->first_insn_idx = env->subprog_info[subprog].start;
+ state->last_insn_idx = -1;
+
+ regs = state->frame[state->curframe]->regs;
+ if (subprog || env->prog->type == BPF_PROG_TYPE_EXT) {
+ ret = btf_prepare_func_args(env, subprog, regs);
+ if (ret)
+ goto out;
+ for (i = BPF_REG_1; i <= BPF_REG_5; i++) {
+ if (regs[i].type == PTR_TO_CTX)
+ mark_reg_known_zero(env, regs, i);
+ else if (regs[i].type == SCALAR_VALUE)
+ mark_reg_unknown(env, regs, i);
+ else if (base_type(regs[i].type) == PTR_TO_MEM) {
+ const u32 mem_size = regs[i].mem_size;
+
+ mark_reg_known_zero(env, regs, i);
+ regs[i].mem_size = mem_size;
+ regs[i].id = ++env->id_gen;
+ }
+ }
+ } else {
+ /* 1st arg to a function */
+ regs[BPF_REG_1].type = PTR_TO_CTX;
+ mark_reg_known_zero(env, regs, BPF_REG_1);
+ ret = btf_check_subprog_arg_match(env, subprog, regs);
+ if (ret == -EFAULT)
+ /* unlikely verifier bug. abort.
+ * ret == 0 and ret < 0 are sadly acceptable for
+ * main() function due to backward compatibility.
+ * Like socket filter program may be written as:
+ * int bpf_prog(struct pt_regs *ctx)
+ * and never dereference that ctx in the program.
+ * 'struct pt_regs' is a type mismatch for socket
+ * filter that should be using 'struct __sk_buff'.
+ */
+ goto out;
+ }
+
+ ret = do_check(env);
+out:
+ /* check for NULL is necessary, since cur_state can be freed inside
+ * do_check() under memory pressure.
+ */
+ if (env->cur_state) {
+ free_verifier_state(env->cur_state, true);
+ env->cur_state = NULL;
+ }
+ while (!pop_stack(env, NULL, NULL, false));
+ if (!ret && pop_log)
+ bpf_vlog_reset(&env->log, 0);
+ free_states(env);
+ return ret;
+}
+
+/* Verify all global functions in a BPF program one by one based on their BTF.
+ * All global functions must pass verification. Otherwise the whole program is rejected.
+ * Consider:
+ * int bar(int);
+ * int foo(int f)
+ * {
+ * return bar(f);
+ * }
+ * int bar(int b)
+ * {
+ * ...
+ * }
+ * foo() will be verified first for R1=any_scalar_value. During verification it
+ * will be assumed that bar() already verified successfully and call to bar()
+ * from foo() will be checked for type match only. Later bar() will be verified
+ * independently to check that it's safe for R1=any_scalar_value.
+ */
+static int do_check_subprogs(struct bpf_verifier_env *env)
+{
+ struct bpf_prog_aux *aux = env->prog->aux;
+ int i, ret;
+
+ if (!aux->func_info)
+ return 0;
+
+ for (i = 1; i < env->subprog_cnt; i++) {
+ if (aux->func_info_aux[i].linkage != BTF_FUNC_GLOBAL)
+ continue;
+ env->insn_idx = env->subprog_info[i].start;
+ WARN_ON_ONCE(env->insn_idx == 0);
+ ret = do_check_common(env, i);
+ if (ret) {
+ return ret;
+ } else if (env->log.level & BPF_LOG_LEVEL) {
+ verbose(env,
+ "Func#%d is safe for any args that match its prototype\n",
+ i);
+ }
+ }
+ return 0;
+}
+
+static int do_check_main(struct bpf_verifier_env *env)
+{
+ int ret;
+
+ env->insn_idx = 0;
+ ret = do_check_common(env, 0);
+ if (!ret)
+ env->prog->aux->stack_depth = env->subprog_info[0].stack_depth;
+ return ret;
+}
+
+
+static void print_verification_stats(struct bpf_verifier_env *env)
+{
+ int i;
+
+ if (env->log.level & BPF_LOG_STATS) {
+ verbose(env, "verification time %lld usec\n",
+ div_u64(env->verification_time, 1000));
+ verbose(env, "stack depth ");
+ for (i = 0; i < env->subprog_cnt; i++) {
+ u32 depth = env->subprog_info[i].stack_depth;
+
+ verbose(env, "%d", depth);
+ if (i + 1 < env->subprog_cnt)
+ verbose(env, "+");
+ }
+ verbose(env, "\n");
+ }
+ verbose(env, "processed %d insns (limit %d) max_states_per_insn %d "
+ "total_states %d peak_states %d mark_read %d\n",
+ env->insn_processed, BPF_COMPLEXITY_LIMIT_INSNS,
+ env->max_states_per_insn, env->total_states,
+ env->peak_states, env->longest_mark_read_walk);
+}
+
+static int check_struct_ops_btf_id(struct bpf_verifier_env *env)
+{
+ const struct btf_type *t, *func_proto;
+ const struct bpf_struct_ops *st_ops;
+ const struct btf_member *member;
+ struct bpf_prog *prog = env->prog;
+ u32 btf_id, member_idx;
+ const char *mname;
+
+ if (!prog->gpl_compatible) {
+ verbose(env, "struct ops programs must have a GPL compatible license\n");
+ return -EINVAL;
+ }
+
+ btf_id = prog->aux->attach_btf_id;
+ st_ops = bpf_struct_ops_find(btf_id);
+ if (!st_ops) {
+ verbose(env, "attach_btf_id %u is not a supported struct\n",
+ btf_id);
+ return -ENOTSUPP;
+ }
+
+ t = st_ops->type;
+ member_idx = prog->expected_attach_type;
+ if (member_idx >= btf_type_vlen(t)) {
+ verbose(env, "attach to invalid member idx %u of struct %s\n",
+ member_idx, st_ops->name);
+ return -EINVAL;
+ }
+
+ member = &btf_type_member(t)[member_idx];
+ mname = btf_name_by_offset(btf_vmlinux, member->name_off);
+ func_proto = btf_type_resolve_func_ptr(btf_vmlinux, member->type,
+ NULL);
+ if (!func_proto) {
+ verbose(env, "attach to invalid member %s(@idx %u) of struct %s\n",
+ mname, member_idx, st_ops->name);
+ return -EINVAL;
+ }
+
+ if (st_ops->check_member) {
+ int err = st_ops->check_member(t, member, prog);
+
+ if (err) {
+ verbose(env, "attach to unsupported member %s of struct %s\n",
+ mname, st_ops->name);
+ return err;
+ }
+ }
+
+ prog->aux->attach_func_proto = func_proto;
+ prog->aux->attach_func_name = mname;
+ env->ops = st_ops->verifier_ops;
+
+ return 0;
+}
+#define SECURITY_PREFIX "security_"
+
+static int check_attach_modify_return(unsigned long addr, const char *func_name)
+{
+ if (within_error_injection_list(addr) ||
+ !strncmp(SECURITY_PREFIX, func_name, sizeof(SECURITY_PREFIX) - 1))
+ return 0;
+
+ return -EINVAL;
+}
+
+/* list of non-sleepable functions that are otherwise on
+ * ALLOW_ERROR_INJECTION list
+ */
+BTF_SET_START(btf_non_sleepable_error_inject)
+/* Three functions below can be called from sleepable and non-sleepable context.
+ * Assume non-sleepable from bpf safety point of view.
+ */
+BTF_ID(func, __filemap_add_folio)
+BTF_ID(func, should_fail_alloc_page)
+BTF_ID(func, should_failslab)
+BTF_SET_END(btf_non_sleepable_error_inject)
+
+static int check_non_sleepable_error_inject(u32 btf_id)
+{
+ return btf_id_set_contains(&btf_non_sleepable_error_inject, btf_id);
+}
+
+int bpf_check_attach_target(struct bpf_verifier_log *log,
+ const struct bpf_prog *prog,
+ const struct bpf_prog *tgt_prog,
+ u32 btf_id,
+ struct bpf_attach_target_info *tgt_info)
+{
+ bool prog_extension = prog->type == BPF_PROG_TYPE_EXT;
+ const char prefix[] = "btf_trace_";
+ int ret = 0, subprog = -1, i;
+ const struct btf_type *t;
+ bool conservative = true;
+ const char *tname;
+ struct btf *btf;
+ long addr = 0;
+ struct module *mod = NULL;
+
+ if (!btf_id) {
+ bpf_log(log, "Tracing programs must provide btf_id\n");
+ return -EINVAL;
+ }
+ btf = tgt_prog ? tgt_prog->aux->btf : prog->aux->attach_btf;
+ if (!btf) {
+ bpf_log(log,
+ "FENTRY/FEXIT program can only be attached to another program annotated with BTF\n");
+ return -EINVAL;
+ }
+ t = btf_type_by_id(btf, btf_id);
+ if (!t) {
+ bpf_log(log, "attach_btf_id %u is invalid\n", btf_id);
+ return -EINVAL;
+ }
+ tname = btf_name_by_offset(btf, t->name_off);
+ if (!tname) {
+ bpf_log(log, "attach_btf_id %u doesn't have a name\n", btf_id);
+ return -EINVAL;
+ }
+ if (tgt_prog) {
+ struct bpf_prog_aux *aux = tgt_prog->aux;
+
+ if (bpf_prog_is_dev_bound(prog->aux) &&
+ !bpf_prog_dev_bound_match(prog, tgt_prog)) {
+ bpf_log(log, "Target program bound device mismatch");
+ return -EINVAL;
+ }
+
+ for (i = 0; i < aux->func_info_cnt; i++)
+ if (aux->func_info[i].type_id == btf_id) {
+ subprog = i;
+ break;
+ }
+ if (subprog == -1) {
+ bpf_log(log, "Subprog %s doesn't exist\n", tname);
+ return -EINVAL;
+ }
+ conservative = aux->func_info_aux[subprog].unreliable;
+ if (prog_extension) {
+ if (conservative) {
+ bpf_log(log,
+ "Cannot replace static functions\n");
+ return -EINVAL;
+ }
+ if (!prog->jit_requested) {
+ bpf_log(log,
+ "Extension programs should be JITed\n");
+ return -EINVAL;
+ }
+ }
+ if (!tgt_prog->jited) {
+ bpf_log(log, "Can attach to only JITed progs\n");
+ return -EINVAL;
+ }
+ if (tgt_prog->type == prog->type) {
+ /* Cannot fentry/fexit another fentry/fexit program.
+ * Cannot attach program extension to another extension.
+ * It's ok to attach fentry/fexit to extension program.
+ */
+ bpf_log(log, "Cannot recursively attach\n");
+ return -EINVAL;
+ }
+ if (tgt_prog->type == BPF_PROG_TYPE_TRACING &&
+ prog_extension &&
+ (tgt_prog->expected_attach_type == BPF_TRACE_FENTRY ||
+ tgt_prog->expected_attach_type == BPF_TRACE_FEXIT)) {
+ /* Program extensions can extend all program types
+ * except fentry/fexit. The reason is the following.
+ * The fentry/fexit programs are used for performance
+ * analysis, stats and can be attached to any program
+ * type except themselves. When extension program is
+ * replacing XDP function it is necessary to allow
+ * performance analysis of all functions. Both original
+ * XDP program and its program extension. Hence
+ * attaching fentry/fexit to BPF_PROG_TYPE_EXT is
+ * allowed. If extending of fentry/fexit was allowed it
+ * would be possible to create long call chain
+ * fentry->extension->fentry->extension beyond
+ * reasonable stack size. Hence extending fentry is not
+ * allowed.
+ */
+ bpf_log(log, "Cannot extend fentry/fexit\n");
+ return -EINVAL;
+ }
+ } else {
+ if (prog_extension) {
+ bpf_log(log, "Cannot replace kernel functions\n");
+ return -EINVAL;
+ }
+ }
+
+ switch (prog->expected_attach_type) {
+ case BPF_TRACE_RAW_TP:
+ if (tgt_prog) {
+ bpf_log(log,
+ "Only FENTRY/FEXIT progs are attachable to another BPF prog\n");
+ return -EINVAL;
+ }
+ if (!btf_type_is_typedef(t)) {
+ bpf_log(log, "attach_btf_id %u is not a typedef\n",
+ btf_id);
+ return -EINVAL;
+ }
+ if (strncmp(prefix, tname, sizeof(prefix) - 1)) {
+ bpf_log(log, "attach_btf_id %u points to wrong type name %s\n",
+ btf_id, tname);
+ return -EINVAL;
+ }
+ tname += sizeof(prefix) - 1;
+ t = btf_type_by_id(btf, t->type);
+ if (!btf_type_is_ptr(t))
+ /* should never happen in valid vmlinux build */
+ return -EINVAL;
+ t = btf_type_by_id(btf, t->type);
+ if (!btf_type_is_func_proto(t))
+ /* should never happen in valid vmlinux build */
+ return -EINVAL;
+
+ break;
+ case BPF_TRACE_ITER:
+ if (!btf_type_is_func(t)) {
+ bpf_log(log, "attach_btf_id %u is not a function\n",
+ btf_id);
+ return -EINVAL;
+ }
+ t = btf_type_by_id(btf, t->type);
+ if (!btf_type_is_func_proto(t))
+ return -EINVAL;
+ ret = btf_distill_func_proto(log, btf, t, tname, &tgt_info->fmodel);
+ if (ret)
+ return ret;
+ break;
+ default:
+ if (!prog_extension)
+ return -EINVAL;
+ fallthrough;
+ case BPF_MODIFY_RETURN:
+ case BPF_LSM_MAC:
+ case BPF_LSM_CGROUP:
+ case BPF_TRACE_FENTRY:
+ case BPF_TRACE_FEXIT:
+ if (!btf_type_is_func(t)) {
+ bpf_log(log, "attach_btf_id %u is not a function\n",
+ btf_id);
+ return -EINVAL;
+ }
+ if (prog_extension &&
+ btf_check_type_match(log, prog, btf, t))
+ return -EINVAL;
+ t = btf_type_by_id(btf, t->type);
+ if (!btf_type_is_func_proto(t))
+ return -EINVAL;
+
+ if ((prog->aux->saved_dst_prog_type || prog->aux->saved_dst_attach_type) &&
+ (!tgt_prog || prog->aux->saved_dst_prog_type != tgt_prog->type ||
+ prog->aux->saved_dst_attach_type != tgt_prog->expected_attach_type))
+ return -EINVAL;
+
+ if (tgt_prog && conservative)
+ t = NULL;
+
+ ret = btf_distill_func_proto(log, btf, t, tname, &tgt_info->fmodel);
+ if (ret < 0)
+ return ret;
+
+ if (tgt_prog) {
+ if (subprog == 0)
+ addr = (long) tgt_prog->bpf_func;
+ else
+ addr = (long) tgt_prog->aux->func[subprog]->bpf_func;
+ } else {
+ if (btf_is_module(btf)) {
+ mod = btf_try_get_module(btf);
+ if (mod)
+ addr = find_kallsyms_symbol_value(mod, tname);
+ else
+ addr = 0;
+ } else {
+ addr = kallsyms_lookup_name(tname);
+ }
+ if (!addr) {
+ module_put(mod);
+ bpf_log(log,
+ "The address of function %s cannot be found\n",
+ tname);
+ return -ENOENT;
+ }
+ }
+
+ if (prog->aux->sleepable) {
+ ret = -EINVAL;
+ switch (prog->type) {
+ case BPF_PROG_TYPE_TRACING:
+
+ /* fentry/fexit/fmod_ret progs can be sleepable if they are
+ * attached to ALLOW_ERROR_INJECTION and are not in denylist.
+ */
+ if (!check_non_sleepable_error_inject(btf_id) &&
+ within_error_injection_list(addr))
+ ret = 0;
+ /* fentry/fexit/fmod_ret progs can also be sleepable if they are
+ * in the fmodret id set with the KF_SLEEPABLE flag.
+ */
+ else {
+ u32 *flags = btf_kfunc_is_modify_return(btf, btf_id,
+ prog);
+
+ if (flags && (*flags & KF_SLEEPABLE))
+ ret = 0;
+ }
+ break;
+ case BPF_PROG_TYPE_LSM:
+ /* LSM progs check that they are attached to bpf_lsm_*() funcs.
+ * Only some of them are sleepable.
+ */
+ if (bpf_lsm_is_sleepable_hook(btf_id))
+ ret = 0;
+ break;
+ default:
+ break;
+ }
+ if (ret) {
+ module_put(mod);
+ bpf_log(log, "%s is not sleepable\n", tname);
+ return ret;
+ }
+ } else if (prog->expected_attach_type == BPF_MODIFY_RETURN) {
+ if (tgt_prog) {
+ module_put(mod);
+ bpf_log(log, "can't modify return codes of BPF programs\n");
+ return -EINVAL;
+ }
+ ret = -EINVAL;
+ if (btf_kfunc_is_modify_return(btf, btf_id, prog) ||
+ !check_attach_modify_return(addr, tname))
+ ret = 0;
+ if (ret) {
+ module_put(mod);
+ bpf_log(log, "%s() is not modifiable\n", tname);
+ return ret;
+ }
+ }
+
+ break;
+ }
+ tgt_info->tgt_addr = addr;
+ tgt_info->tgt_name = tname;
+ tgt_info->tgt_type = t;
+ tgt_info->tgt_mod = mod;
+ return 0;
+}
+
+BTF_SET_START(btf_id_deny)
+BTF_ID_UNUSED
+#ifdef CONFIG_SMP
+BTF_ID(func, migrate_disable)
+BTF_ID(func, migrate_enable)
+#endif
+#if !defined CONFIG_PREEMPT_RCU && !defined CONFIG_TINY_RCU
+BTF_ID(func, rcu_read_unlock_strict)
+#endif
+#if defined(CONFIG_DEBUG_PREEMPT) || defined(CONFIG_TRACE_PREEMPT_TOGGLE)
+BTF_ID(func, preempt_count_add)
+BTF_ID(func, preempt_count_sub)
+#endif
+#ifdef CONFIG_PREEMPT_RCU
+BTF_ID(func, __rcu_read_lock)
+BTF_ID(func, __rcu_read_unlock)
+#endif
+BTF_SET_END(btf_id_deny)
+
+static bool can_be_sleepable(struct bpf_prog *prog)
+{
+ if (prog->type == BPF_PROG_TYPE_TRACING) {
+ switch (prog->expected_attach_type) {
+ case BPF_TRACE_FENTRY:
+ case BPF_TRACE_FEXIT:
+ case BPF_MODIFY_RETURN:
+ case BPF_TRACE_ITER:
+ return true;
+ default:
+ return false;
+ }
+ }
+ return prog->type == BPF_PROG_TYPE_LSM ||
+ prog->type == BPF_PROG_TYPE_KPROBE /* only for uprobes */ ||
+ prog->type == BPF_PROG_TYPE_STRUCT_OPS;
+}
+
+static int check_attach_btf_id(struct bpf_verifier_env *env)
+{
+ struct bpf_prog *prog = env->prog;
+ struct bpf_prog *tgt_prog = prog->aux->dst_prog;
+ struct bpf_attach_target_info tgt_info = {};
+ u32 btf_id = prog->aux->attach_btf_id;
+ struct bpf_trampoline *tr;
+ int ret;
+ u64 key;
+
+ if (prog->type == BPF_PROG_TYPE_SYSCALL) {
+ if (prog->aux->sleepable)
+ /* attach_btf_id checked to be zero already */
+ return 0;
+ verbose(env, "Syscall programs can only be sleepable\n");
+ return -EINVAL;
+ }
+
+ if (prog->aux->sleepable && !can_be_sleepable(prog)) {
+ verbose(env, "Only fentry/fexit/fmod_ret, lsm, iter, uprobe, and struct_ops programs can be sleepable\n");
+ return -EINVAL;
+ }
+
+ if (prog->type == BPF_PROG_TYPE_STRUCT_OPS)
+ return check_struct_ops_btf_id(env);
+
+ if (prog->type != BPF_PROG_TYPE_TRACING &&
+ prog->type != BPF_PROG_TYPE_LSM &&
+ prog->type != BPF_PROG_TYPE_EXT)
+ return 0;
+
+ ret = bpf_check_attach_target(&env->log, prog, tgt_prog, btf_id, &tgt_info);
+ if (ret)
+ return ret;
+
+ if (tgt_prog && prog->type == BPF_PROG_TYPE_EXT) {
+ /* to make freplace equivalent to their targets, they need to
+ * inherit env->ops and expected_attach_type for the rest of the
+ * verification
+ */
+ env->ops = bpf_verifier_ops[tgt_prog->type];
+ prog->expected_attach_type = tgt_prog->expected_attach_type;
+ }
+
+ /* store info about the attachment target that will be used later */
+ prog->aux->attach_func_proto = tgt_info.tgt_type;
+ prog->aux->attach_func_name = tgt_info.tgt_name;
+ prog->aux->mod = tgt_info.tgt_mod;
+
+ if (tgt_prog) {
+ prog->aux->saved_dst_prog_type = tgt_prog->type;
+ prog->aux->saved_dst_attach_type = tgt_prog->expected_attach_type;
+ }
+
+ if (prog->expected_attach_type == BPF_TRACE_RAW_TP) {
+ prog->aux->attach_btf_trace = true;
+ return 0;
+ } else if (prog->expected_attach_type == BPF_TRACE_ITER) {
+ if (!bpf_iter_prog_supported(prog))
+ return -EINVAL;
+ return 0;
+ }
+
+ if (prog->type == BPF_PROG_TYPE_LSM) {
+ ret = bpf_lsm_verify_prog(&env->log, prog);
+ if (ret < 0)
+ return ret;
+ } else if (prog->type == BPF_PROG_TYPE_TRACING &&
+ btf_id_set_contains(&btf_id_deny, btf_id)) {
+ return -EINVAL;
+ }
+
+ key = bpf_trampoline_compute_key(tgt_prog, prog->aux->attach_btf, btf_id);
+ tr = bpf_trampoline_get(key, &tgt_info);
+ if (!tr)
+ return -ENOMEM;
+
+ if (tgt_prog && tgt_prog->aux->tail_call_reachable)
+ tr->flags = BPF_TRAMP_F_TAIL_CALL_CTX;
+
+ prog->aux->dst_trampoline = tr;
+ return 0;
+}
+
+struct btf *bpf_get_btf_vmlinux(void)
+{
+ if (!btf_vmlinux && IS_ENABLED(CONFIG_DEBUG_INFO_BTF)) {
+ mutex_lock(&bpf_verifier_lock);
+ if (!btf_vmlinux)
+ btf_vmlinux = btf_parse_vmlinux();
+ mutex_unlock(&bpf_verifier_lock);
+ }
+ return btf_vmlinux;
+}
+
+int bpf_check(struct bpf_prog **prog, union bpf_attr *attr, bpfptr_t uattr, __u32 uattr_size)
+{
+ u64 start_time = ktime_get_ns();
+ struct bpf_verifier_env *env;
+ int i, len, ret = -EINVAL, err;
+ u32 log_true_size;
+ bool is_priv;
+
+ /* no program is valid */
+ if (ARRAY_SIZE(bpf_verifier_ops) == 0)
+ return -EINVAL;
+
+ /* 'struct bpf_verifier_env' can be global, but since it's not small,
+ * allocate/free it every time bpf_check() is called
+ */
+ env = kzalloc(sizeof(struct bpf_verifier_env), GFP_KERNEL);
+ if (!env)
+ return -ENOMEM;
+
+ env->bt.env = env;
+
+ len = (*prog)->len;
+ env->insn_aux_data =
+ vzalloc(array_size(sizeof(struct bpf_insn_aux_data), len));
+ ret = -ENOMEM;
+ if (!env->insn_aux_data)
+ goto err_free_env;
+ for (i = 0; i < len; i++)
+ env->insn_aux_data[i].orig_idx = i;
+ env->prog = *prog;
+ env->ops = bpf_verifier_ops[env->prog->type];
+ env->fd_array = make_bpfptr(attr->fd_array, uattr.is_kernel);
+ is_priv = bpf_capable();
+
+ bpf_get_btf_vmlinux();
+
+ /* grab the mutex to protect few globals used by verifier */
+ if (!is_priv)
+ mutex_lock(&bpf_verifier_lock);
+
+ /* user could have requested verbose verifier output
+ * and supplied buffer to store the verification trace
+ */
+ ret = bpf_vlog_init(&env->log, attr->log_level,
+ (char __user *) (unsigned long) attr->log_buf,
+ attr->log_size);
+ if (ret)
+ goto err_unlock;
+
+ mark_verifier_state_clean(env);
+
+ if (IS_ERR(btf_vmlinux)) {
+ /* Either gcc or pahole or kernel are broken. */
+ verbose(env, "in-kernel BTF is malformed\n");
+ ret = PTR_ERR(btf_vmlinux);
+ goto skip_full_check;
+ }
+
+ env->strict_alignment = !!(attr->prog_flags & BPF_F_STRICT_ALIGNMENT);
+ if (!IS_ENABLED(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS))
+ env->strict_alignment = true;
+ if (attr->prog_flags & BPF_F_ANY_ALIGNMENT)
+ env->strict_alignment = false;
+
+ env->allow_ptr_leaks = bpf_allow_ptr_leaks();
+ env->allow_uninit_stack = bpf_allow_uninit_stack();
+ env->bypass_spec_v1 = bpf_bypass_spec_v1();
+ env->bypass_spec_v4 = bpf_bypass_spec_v4();
+ env->bpf_capable = bpf_capable();
+
+ if (is_priv)
+ env->test_state_freq = attr->prog_flags & BPF_F_TEST_STATE_FREQ;
+
+ env->explored_states = kvcalloc(state_htab_size(env),
+ sizeof(struct bpf_verifier_state_list *),
+ GFP_USER);
+ ret = -ENOMEM;
+ if (!env->explored_states)
+ goto skip_full_check;
+
+ ret = add_subprog_and_kfunc(env);
+ if (ret < 0)
+ goto skip_full_check;
+
+ ret = check_subprogs(env);
+ if (ret < 0)
+ goto skip_full_check;
+
+ ret = check_btf_info(env, attr, uattr);
+ if (ret < 0)
+ goto skip_full_check;
+
+ ret = check_attach_btf_id(env);
+ if (ret)
+ goto skip_full_check;
+
+ ret = resolve_pseudo_ldimm64(env);
+ if (ret < 0)
+ goto skip_full_check;
+
+ if (bpf_prog_is_offloaded(env->prog->aux)) {
+ ret = bpf_prog_offload_verifier_prep(env->prog);
+ if (ret)
+ goto skip_full_check;
+ }
+
+ ret = check_cfg(env);
+ if (ret < 0)
+ goto skip_full_check;
+
+ ret = do_check_subprogs(env);
+ ret = ret ?: do_check_main(env);
+
+ if (ret == 0 && bpf_prog_is_offloaded(env->prog->aux))
+ ret = bpf_prog_offload_finalize(env);
+
+skip_full_check:
+ kvfree(env->explored_states);
+
+ if (ret == 0)
+ ret = check_max_stack_depth(env);
+
+ /* instruction rewrites happen after this point */
+ if (ret == 0)
+ ret = optimize_bpf_loop(env);
+
+ if (is_priv) {
+ if (ret == 0)
+ opt_hard_wire_dead_code_branches(env);
+ if (ret == 0)
+ ret = opt_remove_dead_code(env);
+ if (ret == 0)
+ ret = opt_remove_nops(env);
+ } else {
+ if (ret == 0)
+ sanitize_dead_code(env);
+ }
+
+ if (ret == 0)
+ /* program is valid, convert *(u32*)(ctx + off) accesses */
+ ret = convert_ctx_accesses(env);
+
+ if (ret == 0)
+ ret = do_misc_fixups(env);
+
+ /* do 32-bit optimization after insn patching has done so those patched
+ * insns could be handled correctly.
+ */
+ if (ret == 0 && !bpf_prog_is_offloaded(env->prog->aux)) {
+ ret = opt_subreg_zext_lo32_rnd_hi32(env, attr);
+ env->prog->aux->verifier_zext = bpf_jit_needs_zext() ? !ret
+ : false;
+ }
+
+ if (ret == 0)
+ ret = fixup_call_args(env);
+
+ env->verification_time = ktime_get_ns() - start_time;
+ print_verification_stats(env);
+ env->prog->aux->verified_insns = env->insn_processed;
+
+ /* preserve original error even if log finalization is successful */
+ err = bpf_vlog_finalize(&env->log, &log_true_size);
+ if (err)
+ ret = err;
+
+ if (uattr_size >= offsetofend(union bpf_attr, log_true_size) &&
+ copy_to_bpfptr_offset(uattr, offsetof(union bpf_attr, log_true_size),
+ &log_true_size, sizeof(log_true_size))) {
+ ret = -EFAULT;
+ goto err_release_maps;
+ }
+
+ if (ret)
+ goto err_release_maps;
+
+ if (env->used_map_cnt) {
+ /* if program passed verifier, update used_maps in bpf_prog_info */
+ env->prog->aux->used_maps = kmalloc_array(env->used_map_cnt,
+ sizeof(env->used_maps[0]),
+ GFP_KERNEL);
+
+ if (!env->prog->aux->used_maps) {
+ ret = -ENOMEM;
+ goto err_release_maps;
+ }
+
+ memcpy(env->prog->aux->used_maps, env->used_maps,
+ sizeof(env->used_maps[0]) * env->used_map_cnt);
+ env->prog->aux->used_map_cnt = env->used_map_cnt;
+ }
+ if (env->used_btf_cnt) {
+ /* if program passed verifier, update used_btfs in bpf_prog_aux */
+ env->prog->aux->used_btfs = kmalloc_array(env->used_btf_cnt,
+ sizeof(env->used_btfs[0]),
+ GFP_KERNEL);
+ if (!env->prog->aux->used_btfs) {
+ ret = -ENOMEM;
+ goto err_release_maps;
+ }
+
+ memcpy(env->prog->aux->used_btfs, env->used_btfs,
+ sizeof(env->used_btfs[0]) * env->used_btf_cnt);
+ env->prog->aux->used_btf_cnt = env->used_btf_cnt;
+ }
+ if (env->used_map_cnt || env->used_btf_cnt) {
+ /* program is valid. Convert pseudo bpf_ld_imm64 into generic
+ * bpf_ld_imm64 instructions
+ */
+ convert_pseudo_ld_imm64(env);
+ }
+
+ adjust_btf_func(env);
+
+err_release_maps:
+ if (!env->prog->aux->used_maps)
+ /* if we didn't copy map pointers into bpf_prog_info, release
+ * them now. Otherwise free_used_maps() will release them.
+ */
+ release_maps(env);
+ if (!env->prog->aux->used_btfs)
+ release_btfs(env);
+
+ /* extension progs temporarily inherit the attach_type of their targets
+ for verification purposes, so set it back to zero before returning
+ */
+ if (env->prog->type == BPF_PROG_TYPE_EXT)
+ env->prog->expected_attach_type = 0;
+
+ *prog = env->prog;
+err_unlock:
+ if (!is_priv)
+ mutex_unlock(&bpf_verifier_lock);
+ vfree(env->insn_aux_data);
+err_free_env:
+ kfree(env);
+ return ret;
+}