diff options
Diffstat (limited to 'kernel/bpf/core.c')
| -rw-r--r-- | kernel/bpf/core.c | 1945 |
1 files changed, 1945 insertions, 0 deletions
diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c new file mode 100644 index 000000000..4e5b5ae05 --- /dev/null +++ b/kernel/bpf/core.c @@ -0,0 +1,1945 @@ +/* + * Linux Socket Filter - Kernel level socket filtering + * + * Based on the design of the Berkeley Packet Filter. The new + * internal format has been designed by PLUMgrid: + * + * Copyright (c) 2011 - 2014 PLUMgrid, http://plumgrid.com + * + * Authors: + * + * Jay Schulist <jschlst@samba.org> + * Alexei Starovoitov <ast@plumgrid.com> + * Daniel Borkmann <dborkman@redhat.com> + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; either version + * 2 of the License, or (at your option) any later version. + * + * Andi Kleen - Fix a few bad bugs and races. + * Kris Katterjohn - Added many additional checks in bpf_check_classic() + */ + +#include <linux/filter.h> +#include <linux/skbuff.h> +#include <linux/vmalloc.h> +#include <linux/random.h> +#include <linux/moduleloader.h> +#include <linux/bpf.h> +#include <linux/frame.h> +#include <linux/rbtree_latch.h> +#include <linux/kallsyms.h> +#include <linux/rcupdate.h> +#include <linux/perf_event.h> + +#include <asm/barrier.h> +#include <asm/unaligned.h> + +/* Registers */ +#define BPF_R0 regs[BPF_REG_0] +#define BPF_R1 regs[BPF_REG_1] +#define BPF_R2 regs[BPF_REG_2] +#define BPF_R3 regs[BPF_REG_3] +#define BPF_R4 regs[BPF_REG_4] +#define BPF_R5 regs[BPF_REG_5] +#define BPF_R6 regs[BPF_REG_6] +#define BPF_R7 regs[BPF_REG_7] +#define BPF_R8 regs[BPF_REG_8] +#define BPF_R9 regs[BPF_REG_9] +#define BPF_R10 regs[BPF_REG_10] + +/* Named registers */ +#define DST regs[insn->dst_reg] +#define SRC regs[insn->src_reg] +#define FP regs[BPF_REG_FP] +#define AX regs[BPF_REG_AX] +#define ARG1 regs[BPF_REG_ARG1] +#define CTX regs[BPF_REG_CTX] +#define IMM insn->imm + +/* No hurry in this branch + * + * Exported for the bpf jit load helper. + */ +void *bpf_internal_load_pointer_neg_helper(const struct sk_buff *skb, int k, unsigned int size) +{ + u8 *ptr = NULL; + + if (k >= SKF_NET_OFF) + ptr = skb_network_header(skb) + k - SKF_NET_OFF; + else if (k >= SKF_LL_OFF) + ptr = skb_mac_header(skb) + k - SKF_LL_OFF; + + if (ptr >= skb->head && ptr + size <= skb_tail_pointer(skb)) + return ptr; + + return NULL; +} + +struct bpf_prog *bpf_prog_alloc(unsigned int size, gfp_t gfp_extra_flags) +{ + gfp_t gfp_flags = GFP_KERNEL | __GFP_ZERO | gfp_extra_flags; + struct bpf_prog_aux *aux; + struct bpf_prog *fp; + + size = round_up(size, PAGE_SIZE); + fp = __vmalloc(size, gfp_flags, PAGE_KERNEL); + if (fp == NULL) + return NULL; + + aux = kzalloc(sizeof(*aux), GFP_KERNEL | gfp_extra_flags); + if (aux == NULL) { + vfree(fp); + return NULL; + } + + fp->pages = size / PAGE_SIZE; + fp->aux = aux; + fp->aux->prog = fp; + fp->jit_requested = ebpf_jit_enabled(); + + INIT_LIST_HEAD_RCU(&fp->aux->ksym_lnode); + + return fp; +} +EXPORT_SYMBOL_GPL(bpf_prog_alloc); + +struct bpf_prog *bpf_prog_realloc(struct bpf_prog *fp_old, unsigned int size, + gfp_t gfp_extra_flags) +{ + gfp_t gfp_flags = GFP_KERNEL | __GFP_ZERO | gfp_extra_flags; + struct bpf_prog *fp; + u32 pages, delta; + int ret; + + BUG_ON(fp_old == NULL); + + size = round_up(size, PAGE_SIZE); + pages = size / PAGE_SIZE; + if (pages <= fp_old->pages) + return fp_old; + + delta = pages - fp_old->pages; + ret = __bpf_prog_charge(fp_old->aux->user, delta); + if (ret) + return NULL; + + fp = __vmalloc(size, gfp_flags, PAGE_KERNEL); + if (fp == NULL) { + __bpf_prog_uncharge(fp_old->aux->user, delta); + } else { + memcpy(fp, fp_old, fp_old->pages * PAGE_SIZE); + fp->pages = pages; + fp->aux->prog = fp; + + /* We keep fp->aux from fp_old around in the new + * reallocated structure. + */ + fp_old->aux = NULL; + __bpf_prog_free(fp_old); + } + + return fp; +} + +void __bpf_prog_free(struct bpf_prog *fp) +{ + kfree(fp->aux); + vfree(fp); +} + +int bpf_prog_calc_tag(struct bpf_prog *fp) +{ + const u32 bits_offset = SHA_MESSAGE_BYTES - sizeof(__be64); + u32 raw_size = bpf_prog_tag_scratch_size(fp); + u32 digest[SHA_DIGEST_WORDS]; + u32 ws[SHA_WORKSPACE_WORDS]; + u32 i, bsize, psize, blocks; + struct bpf_insn *dst; + bool was_ld_map; + u8 *raw, *todo; + __be32 *result; + __be64 *bits; + + raw = vmalloc(raw_size); + if (!raw) + return -ENOMEM; + + sha_init(digest); + memset(ws, 0, sizeof(ws)); + + /* We need to take out the map fd for the digest calculation + * since they are unstable from user space side. + */ + dst = (void *)raw; + for (i = 0, was_ld_map = false; i < fp->len; i++) { + dst[i] = fp->insnsi[i]; + if (!was_ld_map && + dst[i].code == (BPF_LD | BPF_IMM | BPF_DW) && + dst[i].src_reg == BPF_PSEUDO_MAP_FD) { + was_ld_map = true; + dst[i].imm = 0; + } else if (was_ld_map && + dst[i].code == 0 && + dst[i].dst_reg == 0 && + dst[i].src_reg == 0 && + dst[i].off == 0) { + was_ld_map = false; + dst[i].imm = 0; + } else { + was_ld_map = false; + } + } + + psize = bpf_prog_insn_size(fp); + memset(&raw[psize], 0, raw_size - psize); + raw[psize++] = 0x80; + + bsize = round_up(psize, SHA_MESSAGE_BYTES); + blocks = bsize / SHA_MESSAGE_BYTES; + todo = raw; + if (bsize - psize >= sizeof(__be64)) { + bits = (__be64 *)(todo + bsize - sizeof(__be64)); + } else { + bits = (__be64 *)(todo + bsize + bits_offset); + blocks++; + } + *bits = cpu_to_be64((psize - 1) << 3); + + while (blocks--) { + sha_transform(digest, todo, ws); + todo += SHA_MESSAGE_BYTES; + } + + result = (__force __be32 *)digest; + for (i = 0; i < SHA_DIGEST_WORDS; i++) + result[i] = cpu_to_be32(digest[i]); + memcpy(fp->tag, result, sizeof(fp->tag)); + + vfree(raw); + return 0; +} + +static int bpf_adj_delta_to_imm(struct bpf_insn *insn, u32 pos, u32 delta, + u32 curr, const bool probe_pass) +{ + const s64 imm_min = S32_MIN, imm_max = S32_MAX; + s64 imm = insn->imm; + + if (curr < pos && curr + imm + 1 > pos) + imm += delta; + else if (curr > pos + delta && curr + imm + 1 <= pos + delta) + imm -= delta; + if (imm < imm_min || imm > imm_max) + return -ERANGE; + if (!probe_pass) + insn->imm = imm; + return 0; +} + +static int bpf_adj_delta_to_off(struct bpf_insn *insn, u32 pos, u32 delta, + u32 curr, const bool probe_pass) +{ + const s32 off_min = S16_MIN, off_max = S16_MAX; + s32 off = insn->off; + + if (curr < pos && curr + off + 1 > pos) + off += delta; + else if (curr > pos + delta && curr + off + 1 <= pos + delta) + off -= delta; + if (off < off_min || off > off_max) + return -ERANGE; + if (!probe_pass) + insn->off = off; + return 0; +} + +static int bpf_adj_branches(struct bpf_prog *prog, u32 pos, u32 delta, + const bool probe_pass) +{ + u32 i, insn_cnt = prog->len + (probe_pass ? delta : 0); + struct bpf_insn *insn = prog->insnsi; + int ret = 0; + + for (i = 0; i < insn_cnt; i++, insn++) { + u8 code; + + /* In the probing pass we still operate on the original, + * unpatched image in order to check overflows before we + * do any other adjustments. Therefore skip the patchlet. + */ + if (probe_pass && i == pos) { + i += delta + 1; + insn++; + } + code = insn->code; + if (BPF_CLASS(code) != BPF_JMP || + BPF_OP(code) == BPF_EXIT) + continue; + /* Adjust offset of jmps if we cross patch boundaries. */ + if (BPF_OP(code) == BPF_CALL) { + if (insn->src_reg != BPF_PSEUDO_CALL) + continue; + ret = bpf_adj_delta_to_imm(insn, pos, delta, i, + probe_pass); + } else { + ret = bpf_adj_delta_to_off(insn, pos, delta, i, + probe_pass); + } + if (ret) + break; + } + + return ret; +} + +struct bpf_prog *bpf_patch_insn_single(struct bpf_prog *prog, u32 off, + const struct bpf_insn *patch, u32 len) +{ + u32 insn_adj_cnt, insn_rest, insn_delta = len - 1; + const u32 cnt_max = S16_MAX; + struct bpf_prog *prog_adj; + + /* Since our patchlet doesn't expand the image, we're done. */ + if (insn_delta == 0) { + memcpy(prog->insnsi + off, patch, sizeof(*patch)); + return prog; + } + + insn_adj_cnt = prog->len + insn_delta; + + /* Reject anything that would potentially let the insn->off + * target overflow when we have excessive program expansions. + * We need to probe here before we do any reallocation where + * we afterwards may not fail anymore. + */ + if (insn_adj_cnt > cnt_max && + bpf_adj_branches(prog, off, insn_delta, true)) + return NULL; + + /* Several new instructions need to be inserted. Make room + * for them. Likely, there's no need for a new allocation as + * last page could have large enough tailroom. + */ + prog_adj = bpf_prog_realloc(prog, bpf_prog_size(insn_adj_cnt), + GFP_USER); + if (!prog_adj) + return NULL; + + prog_adj->len = insn_adj_cnt; + + /* Patching happens in 3 steps: + * + * 1) Move over tail of insnsi from next instruction onwards, + * so we can patch the single target insn with one or more + * new ones (patching is always from 1 to n insns, n > 0). + * 2) Inject new instructions at the target location. + * 3) Adjust branch offsets if necessary. + */ + insn_rest = insn_adj_cnt - off - len; + + memmove(prog_adj->insnsi + off + len, prog_adj->insnsi + off + 1, + sizeof(*patch) * insn_rest); + memcpy(prog_adj->insnsi + off, patch, sizeof(*patch) * len); + + /* We are guaranteed to not fail at this point, otherwise + * the ship has sailed to reverse to the original state. An + * overflow cannot happen at this point. + */ + BUG_ON(bpf_adj_branches(prog_adj, off, insn_delta, false)); + + return prog_adj; +} + +void bpf_prog_kallsyms_del_subprogs(struct bpf_prog *fp) +{ + int i; + + for (i = 0; i < fp->aux->func_cnt; i++) + bpf_prog_kallsyms_del(fp->aux->func[i]); +} + +void bpf_prog_kallsyms_del_all(struct bpf_prog *fp) +{ + bpf_prog_kallsyms_del_subprogs(fp); + bpf_prog_kallsyms_del(fp); +} + +#ifdef CONFIG_BPF_JIT +/* All BPF JIT sysctl knobs here. */ +int bpf_jit_enable __read_mostly = IS_BUILTIN(CONFIG_BPF_JIT_ALWAYS_ON); +int bpf_jit_harden __read_mostly; +int bpf_jit_kallsyms __read_mostly; +long bpf_jit_limit __read_mostly; +long bpf_jit_limit_max __read_mostly; + +static __always_inline void +bpf_get_prog_addr_region(const struct bpf_prog *prog, + unsigned long *symbol_start, + unsigned long *symbol_end) +{ + const struct bpf_binary_header *hdr = bpf_jit_binary_hdr(prog); + unsigned long addr = (unsigned long)hdr; + + WARN_ON_ONCE(!bpf_prog_ebpf_jited(prog)); + + *symbol_start = addr; + *symbol_end = addr + hdr->pages * PAGE_SIZE; +} + +static void bpf_get_prog_name(const struct bpf_prog *prog, char *sym) +{ + const char *end = sym + KSYM_NAME_LEN; + + BUILD_BUG_ON(sizeof("bpf_prog_") + + sizeof(prog->tag) * 2 + + /* name has been null terminated. + * We should need +1 for the '_' preceding + * the name. However, the null character + * is double counted between the name and the + * sizeof("bpf_prog_") above, so we omit + * the +1 here. + */ + sizeof(prog->aux->name) > KSYM_NAME_LEN); + + sym += snprintf(sym, KSYM_NAME_LEN, "bpf_prog_"); + sym = bin2hex(sym, prog->tag, sizeof(prog->tag)); + if (prog->aux->name[0]) + snprintf(sym, (size_t)(end - sym), "_%s", prog->aux->name); + else + *sym = 0; +} + +static __always_inline unsigned long +bpf_get_prog_addr_start(struct latch_tree_node *n) +{ + unsigned long symbol_start, symbol_end; + const struct bpf_prog_aux *aux; + + aux = container_of(n, struct bpf_prog_aux, ksym_tnode); + bpf_get_prog_addr_region(aux->prog, &symbol_start, &symbol_end); + + return symbol_start; +} + +static __always_inline bool bpf_tree_less(struct latch_tree_node *a, + struct latch_tree_node *b) +{ + return bpf_get_prog_addr_start(a) < bpf_get_prog_addr_start(b); +} + +static __always_inline int bpf_tree_comp(void *key, struct latch_tree_node *n) +{ + unsigned long val = (unsigned long)key; + unsigned long symbol_start, symbol_end; + const struct bpf_prog_aux *aux; + + aux = container_of(n, struct bpf_prog_aux, ksym_tnode); + bpf_get_prog_addr_region(aux->prog, &symbol_start, &symbol_end); + + if (val < symbol_start) + return -1; + if (val >= symbol_end) + return 1; + + return 0; +} + +static const struct latch_tree_ops bpf_tree_ops = { + .less = bpf_tree_less, + .comp = bpf_tree_comp, +}; + +static DEFINE_SPINLOCK(bpf_lock); +static LIST_HEAD(bpf_kallsyms); +static struct latch_tree_root bpf_tree __cacheline_aligned; + +static void bpf_prog_ksym_node_add(struct bpf_prog_aux *aux) +{ + WARN_ON_ONCE(!list_empty(&aux->ksym_lnode)); + list_add_tail_rcu(&aux->ksym_lnode, &bpf_kallsyms); + latch_tree_insert(&aux->ksym_tnode, &bpf_tree, &bpf_tree_ops); +} + +static void bpf_prog_ksym_node_del(struct bpf_prog_aux *aux) +{ + if (list_empty(&aux->ksym_lnode)) + return; + + latch_tree_erase(&aux->ksym_tnode, &bpf_tree, &bpf_tree_ops); + list_del_rcu(&aux->ksym_lnode); +} + +static bool bpf_prog_kallsyms_candidate(const struct bpf_prog *fp) +{ + return fp->jited && !bpf_prog_was_classic(fp); +} + +static bool bpf_prog_kallsyms_verify_off(const struct bpf_prog *fp) +{ + return list_empty(&fp->aux->ksym_lnode) || + fp->aux->ksym_lnode.prev == LIST_POISON2; +} + +void bpf_prog_kallsyms_add(struct bpf_prog *fp) +{ + if (!bpf_prog_kallsyms_candidate(fp) || + !capable(CAP_SYS_ADMIN)) + return; + + spin_lock_bh(&bpf_lock); + bpf_prog_ksym_node_add(fp->aux); + spin_unlock_bh(&bpf_lock); +} + +void bpf_prog_kallsyms_del(struct bpf_prog *fp) +{ + if (!bpf_prog_kallsyms_candidate(fp)) + return; + + spin_lock_bh(&bpf_lock); + bpf_prog_ksym_node_del(fp->aux); + spin_unlock_bh(&bpf_lock); +} + +static struct bpf_prog *bpf_prog_kallsyms_find(unsigned long addr) +{ + struct latch_tree_node *n; + + if (!bpf_jit_kallsyms_enabled()) + return NULL; + + n = latch_tree_find((void *)addr, &bpf_tree, &bpf_tree_ops); + return n ? + container_of(n, struct bpf_prog_aux, ksym_tnode)->prog : + NULL; +} + +const char *__bpf_address_lookup(unsigned long addr, unsigned long *size, + unsigned long *off, char *sym) +{ + unsigned long symbol_start, symbol_end; + struct bpf_prog *prog; + char *ret = NULL; + + rcu_read_lock(); + prog = bpf_prog_kallsyms_find(addr); + if (prog) { + bpf_get_prog_addr_region(prog, &symbol_start, &symbol_end); + bpf_get_prog_name(prog, sym); + + ret = sym; + if (size) + *size = symbol_end - symbol_start; + if (off) + *off = addr - symbol_start; + } + rcu_read_unlock(); + + return ret; +} + +bool is_bpf_text_address(unsigned long addr) +{ + bool ret; + + rcu_read_lock(); + ret = bpf_prog_kallsyms_find(addr) != NULL; + rcu_read_unlock(); + + return ret; +} + +int bpf_get_kallsym(unsigned int symnum, unsigned long *value, char *type, + char *sym) +{ + unsigned long symbol_start, symbol_end; + struct bpf_prog_aux *aux; + unsigned int it = 0; + int ret = -ERANGE; + + if (!bpf_jit_kallsyms_enabled()) + return ret; + + rcu_read_lock(); + list_for_each_entry_rcu(aux, &bpf_kallsyms, ksym_lnode) { + if (it++ != symnum) + continue; + + bpf_get_prog_addr_region(aux->prog, &symbol_start, &symbol_end); + bpf_get_prog_name(aux->prog, sym); + + *value = symbol_start; + *type = BPF_SYM_ELF_TYPE; + + ret = 0; + break; + } + rcu_read_unlock(); + + return ret; +} + +static atomic_long_t bpf_jit_current; + +/* Can be overridden by an arch's JIT compiler if it has a custom, + * dedicated BPF backend memory area, or if neither of the two + * below apply. + */ +u64 __weak bpf_jit_alloc_exec_limit(void) +{ +#if defined(MODULES_VADDR) + return MODULES_END - MODULES_VADDR; +#else + return VMALLOC_END - VMALLOC_START; +#endif +} + +static int __init bpf_jit_charge_init(void) +{ + /* Only used as heuristic here to derive limit. */ + bpf_jit_limit_max = bpf_jit_alloc_exec_limit(); + bpf_jit_limit = min_t(u64, round_up(bpf_jit_limit_max >> 2, + PAGE_SIZE), LONG_MAX); + return 0; +} +pure_initcall(bpf_jit_charge_init); + +static int bpf_jit_charge_modmem(u32 pages) +{ + if (atomic_long_add_return(pages, &bpf_jit_current) > + (bpf_jit_limit >> PAGE_SHIFT)) { + if (!capable(CAP_SYS_ADMIN)) { + atomic_long_sub(pages, &bpf_jit_current); + return -EPERM; + } + } + + return 0; +} + +static void bpf_jit_uncharge_modmem(u32 pages) +{ + atomic_long_sub(pages, &bpf_jit_current); +} + +struct bpf_binary_header * +bpf_jit_binary_alloc(unsigned int proglen, u8 **image_ptr, + unsigned int alignment, + bpf_jit_fill_hole_t bpf_fill_ill_insns) +{ + struct bpf_binary_header *hdr; + u32 size, hole, start, pages; + + /* Most of BPF filters are really small, but if some of them + * fill a page, allow at least 128 extra bytes to insert a + * random section of illegal instructions. + */ + size = round_up(proglen + sizeof(*hdr) + 128, PAGE_SIZE); + pages = size / PAGE_SIZE; + + if (bpf_jit_charge_modmem(pages)) + return NULL; + hdr = module_alloc(size); + if (!hdr) { + bpf_jit_uncharge_modmem(pages); + return NULL; + } + + /* Fill space with illegal/arch-dep instructions. */ + bpf_fill_ill_insns(hdr, size); + + hdr->pages = pages; + hole = min_t(unsigned int, size - (proglen + sizeof(*hdr)), + PAGE_SIZE - sizeof(*hdr)); + start = (get_random_int() % hole) & ~(alignment - 1); + + /* Leave a random number of instructions before BPF code. */ + *image_ptr = &hdr->image[start]; + + return hdr; +} + +void bpf_jit_binary_free(struct bpf_binary_header *hdr) +{ + u32 pages = hdr->pages; + + module_memfree(hdr); + bpf_jit_uncharge_modmem(pages); +} + +/* This symbol is only overridden by archs that have different + * requirements than the usual eBPF JITs, f.e. when they only + * implement cBPF JIT, do not set images read-only, etc. + */ +void __weak bpf_jit_free(struct bpf_prog *fp) +{ + if (fp->jited) { + struct bpf_binary_header *hdr = bpf_jit_binary_hdr(fp); + + bpf_jit_binary_unlock_ro(hdr); + bpf_jit_binary_free(hdr); + + WARN_ON_ONCE(!bpf_prog_kallsyms_verify_off(fp)); + } + + bpf_prog_unlock_free(fp); +} + +static int bpf_jit_blind_insn(const struct bpf_insn *from, + const struct bpf_insn *aux, + struct bpf_insn *to_buff) +{ + struct bpf_insn *to = to_buff; + u32 imm_rnd = get_random_int(); + s16 off; + + BUILD_BUG_ON(BPF_REG_AX + 1 != MAX_BPF_JIT_REG); + BUILD_BUG_ON(MAX_BPF_REG + 1 != MAX_BPF_JIT_REG); + + /* Constraints on AX register: + * + * AX register is inaccessible from user space. It is mapped in + * all JITs, and used here for constant blinding rewrites. It is + * typically "stateless" meaning its contents are only valid within + * the executed instruction, but not across several instructions. + * There are a few exceptions however which are further detailed + * below. + * + * Constant blinding is only used by JITs, not in the interpreter. + * In restricted circumstances, the verifier can also use the AX + * register for rewrites as long as they do not interfere with + * the above cases! + */ + if (from->dst_reg == BPF_REG_AX || from->src_reg == BPF_REG_AX) + goto out; + + if (from->imm == 0 && + (from->code == (BPF_ALU | BPF_MOV | BPF_K) || + from->code == (BPF_ALU64 | BPF_MOV | BPF_K))) { + *to++ = BPF_ALU64_REG(BPF_XOR, from->dst_reg, from->dst_reg); + goto out; + } + + switch (from->code) { + case BPF_ALU | BPF_ADD | BPF_K: + case BPF_ALU | BPF_SUB | BPF_K: + case BPF_ALU | BPF_AND | BPF_K: + case BPF_ALU | BPF_OR | BPF_K: + case BPF_ALU | BPF_XOR | BPF_K: + case BPF_ALU | BPF_MUL | BPF_K: + case BPF_ALU | BPF_MOV | BPF_K: + case BPF_ALU | BPF_DIV | BPF_K: + case BPF_ALU | BPF_MOD | BPF_K: + *to++ = BPF_ALU32_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm); + *to++ = BPF_ALU32_IMM(BPF_XOR, BPF_REG_AX, imm_rnd); + *to++ = BPF_ALU32_REG(from->code, from->dst_reg, BPF_REG_AX); + break; + + case BPF_ALU64 | BPF_ADD | BPF_K: + case BPF_ALU64 | BPF_SUB | BPF_K: + case BPF_ALU64 | BPF_AND | BPF_K: + case BPF_ALU64 | BPF_OR | BPF_K: + case BPF_ALU64 | BPF_XOR | BPF_K: + case BPF_ALU64 | BPF_MUL | BPF_K: + case BPF_ALU64 | BPF_MOV | BPF_K: + case BPF_ALU64 | BPF_DIV | BPF_K: + case BPF_ALU64 | BPF_MOD | BPF_K: + *to++ = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm); + *to++ = BPF_ALU64_IMM(BPF_XOR, BPF_REG_AX, imm_rnd); + *to++ = BPF_ALU64_REG(from->code, from->dst_reg, BPF_REG_AX); + break; + + case BPF_JMP | BPF_JEQ | BPF_K: + case BPF_JMP | BPF_JNE | BPF_K: + case BPF_JMP | BPF_JGT | BPF_K: + case BPF_JMP | BPF_JLT | BPF_K: + case BPF_JMP | BPF_JGE | BPF_K: + case BPF_JMP | BPF_JLE | BPF_K: + case BPF_JMP | BPF_JSGT | BPF_K: + case BPF_JMP | BPF_JSLT | BPF_K: + case BPF_JMP | BPF_JSGE | BPF_K: + case BPF_JMP | BPF_JSLE | BPF_K: + case BPF_JMP | BPF_JSET | BPF_K: + /* Accommodate for extra offset in case of a backjump. */ + off = from->off; + if (off < 0) + off -= 2; + *to++ = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm); + *to++ = BPF_ALU64_IMM(BPF_XOR, BPF_REG_AX, imm_rnd); + *to++ = BPF_JMP_REG(from->code, from->dst_reg, BPF_REG_AX, off); + break; + + case BPF_LD | BPF_IMM | BPF_DW: + *to++ = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ aux[1].imm); + *to++ = BPF_ALU64_IMM(BPF_XOR, BPF_REG_AX, imm_rnd); + *to++ = BPF_ALU64_IMM(BPF_LSH, BPF_REG_AX, 32); + *to++ = BPF_ALU64_REG(BPF_MOV, aux[0].dst_reg, BPF_REG_AX); + break; + case 0: /* Part 2 of BPF_LD | BPF_IMM | BPF_DW. */ + *to++ = BPF_ALU32_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ aux[0].imm); + *to++ = BPF_ALU32_IMM(BPF_XOR, BPF_REG_AX, imm_rnd); + *to++ = BPF_ALU64_REG(BPF_OR, aux[0].dst_reg, BPF_REG_AX); + break; + + case BPF_ST | BPF_MEM | BPF_DW: + case BPF_ST | BPF_MEM | BPF_W: + case BPF_ST | BPF_MEM | BPF_H: + case BPF_ST | BPF_MEM | BPF_B: + *to++ = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm); + *to++ = BPF_ALU64_IMM(BPF_XOR, BPF_REG_AX, imm_rnd); + *to++ = BPF_STX_MEM(from->code, from->dst_reg, BPF_REG_AX, from->off); + break; + } +out: + return to - to_buff; +} + +static struct bpf_prog *bpf_prog_clone_create(struct bpf_prog *fp_other, + gfp_t gfp_extra_flags) +{ + gfp_t gfp_flags = GFP_KERNEL | __GFP_ZERO | gfp_extra_flags; + struct bpf_prog *fp; + + fp = __vmalloc(fp_other->pages * PAGE_SIZE, gfp_flags, PAGE_KERNEL); + if (fp != NULL) { + /* aux->prog still points to the fp_other one, so + * when promoting the clone to the real program, + * this still needs to be adapted. + */ + memcpy(fp, fp_other, fp_other->pages * PAGE_SIZE); + } + + return fp; +} + +static void bpf_prog_clone_free(struct bpf_prog *fp) +{ + /* aux was stolen by the other clone, so we cannot free + * it from this path! It will be freed eventually by the + * other program on release. + * + * At this point, we don't need a deferred release since + * clone is guaranteed to not be locked. + */ + fp->aux = NULL; + __bpf_prog_free(fp); +} + +void bpf_jit_prog_release_other(struct bpf_prog *fp, struct bpf_prog *fp_other) +{ + /* We have to repoint aux->prog to self, as we don't + * know whether fp here is the clone or the original. + */ + fp->aux->prog = fp; + bpf_prog_clone_free(fp_other); +} + +struct bpf_prog *bpf_jit_blind_constants(struct bpf_prog *prog) +{ + struct bpf_insn insn_buff[16], aux[2]; + struct bpf_prog *clone, *tmp; + int insn_delta, insn_cnt; + struct bpf_insn *insn; + int i, rewritten; + + if (!bpf_jit_blinding_enabled(prog) || prog->blinded) + return prog; + + clone = bpf_prog_clone_create(prog, GFP_USER); + if (!clone) + return ERR_PTR(-ENOMEM); + + insn_cnt = clone->len; + insn = clone->insnsi; + + for (i = 0; i < insn_cnt; i++, insn++) { + /* We temporarily need to hold the original ld64 insn + * so that we can still access the first part in the + * second blinding run. + */ + if (insn[0].code == (BPF_LD | BPF_IMM | BPF_DW) && + insn[1].code == 0) + memcpy(aux, insn, sizeof(aux)); + + rewritten = bpf_jit_blind_insn(insn, aux, insn_buff); + if (!rewritten) + continue; + + tmp = bpf_patch_insn_single(clone, i, insn_buff, rewritten); + if (!tmp) { + /* Patching may have repointed aux->prog during + * realloc from the original one, so we need to + * fix it up here on error. + */ + bpf_jit_prog_release_other(prog, clone); + return ERR_PTR(-ENOMEM); + } + + clone = tmp; + insn_delta = rewritten - 1; + + /* Walk new program and skip insns we just inserted. */ + insn = clone->insnsi + i + insn_delta; + insn_cnt += insn_delta; + i += insn_delta; + } + + clone->blinded = 1; + return clone; +} +#endif /* CONFIG_BPF_JIT */ + +/* Base function for offset calculation. Needs to go into .text section, + * therefore keeping it non-static as well; will also be used by JITs + * anyway later on, so do not let the compiler omit it. This also needs + * to go into kallsyms for correlation from e.g. bpftool, so naming + * must not change. + */ +noinline u64 __bpf_call_base(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5) +{ + return 0; +} +EXPORT_SYMBOL_GPL(__bpf_call_base); + +/* All UAPI available opcodes. */ +#define BPF_INSN_MAP(INSN_2, INSN_3) \ + /* 32 bit ALU operations. */ \ + /* Register based. */ \ + INSN_3(ALU, ADD, X), \ + INSN_3(ALU, SUB, X), \ + INSN_3(ALU, AND, X), \ + INSN_3(ALU, OR, X), \ + INSN_3(ALU, LSH, X), \ + INSN_3(ALU, RSH, X), \ + INSN_3(ALU, XOR, X), \ + INSN_3(ALU, MUL, X), \ + INSN_3(ALU, MOV, X), \ + INSN_3(ALU, DIV, X), \ + INSN_3(ALU, MOD, X), \ + INSN_2(ALU, NEG), \ + INSN_3(ALU, END, TO_BE), \ + INSN_3(ALU, END, TO_LE), \ + /* Immediate based. */ \ + INSN_3(ALU, ADD, K), \ + INSN_3(ALU, SUB, K), \ + INSN_3(ALU, AND, K), \ + INSN_3(ALU, OR, K), \ + INSN_3(ALU, LSH, K), \ + INSN_3(ALU, RSH, K), \ + INSN_3(ALU, XOR, K), \ + INSN_3(ALU, MUL, K), \ + INSN_3(ALU, MOV, K), \ + INSN_3(ALU, DIV, K), \ + INSN_3(ALU, MOD, K), \ + /* 64 bit ALU operations. */ \ + /* Register based. */ \ + INSN_3(ALU64, ADD, X), \ + INSN_3(ALU64, SUB, X), \ + INSN_3(ALU64, AND, X), \ + INSN_3(ALU64, OR, X), \ + INSN_3(ALU64, LSH, X), \ + INSN_3(ALU64, RSH, X), \ + INSN_3(ALU64, XOR, X), \ + INSN_3(ALU64, MUL, X), \ + INSN_3(ALU64, MOV, X), \ + INSN_3(ALU64, ARSH, X), \ + INSN_3(ALU64, DIV, X), \ + INSN_3(ALU64, MOD, X), \ + INSN_2(ALU64, NEG), \ + /* Immediate based. */ \ + INSN_3(ALU64, ADD, K), \ + INSN_3(ALU64, SUB, K), \ + INSN_3(ALU64, AND, K), \ + INSN_3(ALU64, OR, K), \ + INSN_3(ALU64, LSH, K), \ + INSN_3(ALU64, RSH, K), \ + INSN_3(ALU64, XOR, K), \ + INSN_3(ALU64, MUL, K), \ + INSN_3(ALU64, MOV, K), \ + INSN_3(ALU64, ARSH, K), \ + INSN_3(ALU64, DIV, K), \ + INSN_3(ALU64, MOD, K), \ + /* Call instruction. */ \ + INSN_2(JMP, CALL), \ + /* Exit instruction. */ \ + INSN_2(JMP, EXIT), \ + /* Jump instructions. */ \ + /* Register based. */ \ + INSN_3(JMP, JEQ, X), \ + INSN_3(JMP, JNE, X), \ + INSN_3(JMP, JGT, X), \ + INSN_3(JMP, JLT, X), \ + INSN_3(JMP, JGE, X), \ + INSN_3(JMP, JLE, X), \ + INSN_3(JMP, JSGT, X), \ + INSN_3(JMP, JSLT, X), \ + INSN_3(JMP, JSGE, X), \ + INSN_3(JMP, JSLE, X), \ + INSN_3(JMP, JSET, X), \ + /* Immediate based. */ \ + INSN_3(JMP, JEQ, K), \ + INSN_3(JMP, JNE, K), \ + INSN_3(JMP, JGT, K), \ + INSN_3(JMP, JLT, K), \ + INSN_3(JMP, JGE, K), \ + INSN_3(JMP, JLE, K), \ + INSN_3(JMP, JSGT, K), \ + INSN_3(JMP, JSLT, K), \ + INSN_3(JMP, JSGE, K), \ + INSN_3(JMP, JSLE, K), \ + INSN_3(JMP, JSET, K), \ + INSN_2(JMP, JA), \ + /* Store instructions. */ \ + /* Register based. */ \ + INSN_3(STX, MEM, B), \ + INSN_3(STX, MEM, H), \ + INSN_3(STX, MEM, W), \ + INSN_3(STX, MEM, DW), \ + INSN_3(STX, XADD, W), \ + INSN_3(STX, XADD, DW), \ + /* Immediate based. */ \ + INSN_3(ST, MEM, B), \ + INSN_3(ST, MEM, H), \ + INSN_3(ST, MEM, W), \ + INSN_3(ST, MEM, DW), \ + /* Load instructions. */ \ + /* Register based. */ \ + INSN_3(LDX, MEM, B), \ + INSN_3(LDX, MEM, H), \ + INSN_3(LDX, MEM, W), \ + INSN_3(LDX, MEM, DW), \ + /* Immediate based. */ \ + INSN_3(LD, IMM, DW) + +bool bpf_opcode_in_insntable(u8 code) +{ +#define BPF_INSN_2_TBL(x, y) [BPF_##x | BPF_##y] = true +#define BPF_INSN_3_TBL(x, y, z) [BPF_##x | BPF_##y | BPF_##z] = true + static const bool public_insntable[256] = { + [0 ... 255] = false, + /* Now overwrite non-defaults ... */ + BPF_INSN_MAP(BPF_INSN_2_TBL, BPF_INSN_3_TBL), + /* UAPI exposed, but rewritten opcodes. cBPF carry-over. */ + [BPF_LD | BPF_ABS | BPF_B] = true, + [BPF_LD | BPF_ABS | BPF_H] = true, + [BPF_LD | BPF_ABS | BPF_W] = true, + [BPF_LD | BPF_IND | BPF_B] = true, + [BPF_LD | BPF_IND | BPF_H] = true, + [BPF_LD | BPF_IND | BPF_W] = true, + }; +#undef BPF_INSN_3_TBL +#undef BPF_INSN_2_TBL + return public_insntable[code]; +} + +#ifndef CONFIG_BPF_JIT_ALWAYS_ON +/** + * __bpf_prog_run - run eBPF program on a given context + * @ctx: is the data we are operating on + * @insn: is the array of eBPF instructions + * + * Decode and execute eBPF instructions. + */ +static u64 ___bpf_prog_run(u64 *regs, const struct bpf_insn *insn, u64 *stack) +{ +#define BPF_INSN_2_LBL(x, y) [BPF_##x | BPF_##y] = &&x##_##y +#define BPF_INSN_3_LBL(x, y, z) [BPF_##x | BPF_##y | BPF_##z] = &&x##_##y##_##z + static const void *jumptable[256] = { + [0 ... 255] = &&default_label, + /* Now overwrite non-defaults ... */ + BPF_INSN_MAP(BPF_INSN_2_LBL, BPF_INSN_3_LBL), + /* Non-UAPI available opcodes. */ + [BPF_JMP | BPF_CALL_ARGS] = &&JMP_CALL_ARGS, + [BPF_JMP | BPF_TAIL_CALL] = &&JMP_TAIL_CALL, + [BPF_ST | BPF_NOSPEC] = &&ST_NOSPEC, + }; +#undef BPF_INSN_3_LBL +#undef BPF_INSN_2_LBL + u32 tail_call_cnt = 0; + u64 tmp; + +#define CONT ({ insn++; goto select_insn; }) +#define CONT_JMP ({ insn++; goto select_insn; }) + +select_insn: + goto *jumptable[insn->code]; + + /* ALU */ +#define ALU(OPCODE, OP) \ + ALU64_##OPCODE##_X: \ + DST = DST OP SRC; \ + CONT; \ + ALU_##OPCODE##_X: \ + DST = (u32) DST OP (u32) SRC; \ + CONT; \ + ALU64_##OPCODE##_K: \ + DST = DST OP IMM; \ + CONT; \ + ALU_##OPCODE##_K: \ + DST = (u32) DST OP (u32) IMM; \ + CONT; + + ALU(ADD, +) + ALU(SUB, -) + ALU(AND, &) + ALU(OR, |) + ALU(LSH, <<) + ALU(RSH, >>) + ALU(XOR, ^) + ALU(MUL, *) +#undef ALU + ALU_NEG: + DST = (u32) -DST; + CONT; + ALU64_NEG: + DST = -DST; + CONT; + ALU_MOV_X: + DST = (u32) SRC; + CONT; + ALU_MOV_K: + DST = (u32) IMM; + CONT; + ALU64_MOV_X: + DST = SRC; + CONT; + ALU64_MOV_K: + DST = IMM; + CONT; + LD_IMM_DW: + DST = (u64) (u32) insn[0].imm | ((u64) (u32) insn[1].imm) << 32; + insn++; + CONT; + ALU64_ARSH_X: + (*(s64 *) &DST) >>= SRC; + CONT; + ALU64_ARSH_K: + (*(s64 *) &DST) >>= IMM; + CONT; + ALU64_MOD_X: + div64_u64_rem(DST, SRC, &tmp); + DST = tmp; + CONT; + ALU_MOD_X: + tmp = (u32) DST; + DST = do_div(tmp, (u32) SRC); + CONT; + ALU64_MOD_K: + div64_u64_rem(DST, IMM, &tmp); + DST = tmp; + CONT; + ALU_MOD_K: + tmp = (u32) DST; + DST = do_div(tmp, (u32) IMM); + CONT; + ALU64_DIV_X: + DST = div64_u64(DST, SRC); + CONT; + ALU_DIV_X: + tmp = (u32) DST; + do_div(tmp, (u32) SRC); + DST = (u32) tmp; + CONT; + ALU64_DIV_K: + DST = div64_u64(DST, IMM); + CONT; + ALU_DIV_K: + tmp = (u32) DST; + do_div(tmp, (u32) IMM); + DST = (u32) tmp; + CONT; + ALU_END_TO_BE: + switch (IMM) { + case 16: + DST = (__force u16) cpu_to_be16(DST); + break; + case 32: + DST = (__force u32) cpu_to_be32(DST); + break; + case 64: + DST = (__force u64) cpu_to_be64(DST); + break; + } + CONT; + ALU_END_TO_LE: + switch (IMM) { + case 16: + DST = (__force u16) cpu_to_le16(DST); + break; + case 32: + DST = (__force u32) cpu_to_le32(DST); + break; + case 64: + DST = (__force u64) cpu_to_le64(DST); + break; + } + CONT; + + /* CALL */ + JMP_CALL: + /* Function call scratches BPF_R1-BPF_R5 registers, + * preserves BPF_R6-BPF_R9, and stores return value + * into BPF_R0. + */ + BPF_R0 = (__bpf_call_base + insn->imm)(BPF_R1, BPF_R2, BPF_R3, + BPF_R4, BPF_R5); + CONT; + + JMP_CALL_ARGS: + BPF_R0 = (__bpf_call_base_args + insn->imm)(BPF_R1, BPF_R2, + BPF_R3, BPF_R4, + BPF_R5, + insn + insn->off + 1); + CONT; + + JMP_TAIL_CALL: { + struct bpf_map *map = (struct bpf_map *) (unsigned long) BPF_R2; + struct bpf_array *array = container_of(map, struct bpf_array, map); + struct bpf_prog *prog; + u32 index = BPF_R3; + + if (unlikely(index >= array->map.max_entries)) + goto out; + if (unlikely(tail_call_cnt > MAX_TAIL_CALL_CNT)) + goto out; + + tail_call_cnt++; + + prog = READ_ONCE(array->ptrs[index]); + if (!prog) + goto out; + + /* ARG1 at this point is guaranteed to point to CTX from + * the verifier side due to the fact that the tail call is + * handeled like a helper, that is, bpf_tail_call_proto, + * where arg1_type is ARG_PTR_TO_CTX. + */ + insn = prog->insnsi; + goto select_insn; +out: + CONT; + } + /* JMP */ + JMP_JA: + insn += insn->off; + CONT; + JMP_JEQ_X: + if (DST == SRC) { + insn += insn->off; + CONT_JMP; + } + CONT; + JMP_JEQ_K: + if (DST == IMM) { + insn += insn->off; + CONT_JMP; + } + CONT; + JMP_JNE_X: + if (DST != SRC) { + insn += insn->off; + CONT_JMP; + } + CONT; + JMP_JNE_K: + if (DST != IMM) { + insn += insn->off; + CONT_JMP; + } + CONT; + JMP_JGT_X: + if (DST > SRC) { + insn += insn->off; + CONT_JMP; + } + CONT; + JMP_JGT_K: + if (DST > IMM) { + insn += insn->off; + CONT_JMP; + } + CONT; + JMP_JLT_X: + if (DST < SRC) { + insn += insn->off; + CONT_JMP; + } + CONT; + JMP_JLT_K: + if (DST < IMM) { + insn += insn->off; + CONT_JMP; + } + CONT; + JMP_JGE_X: + if (DST >= SRC) { + insn += insn->off; + CONT_JMP; + } + CONT; + JMP_JGE_K: + if (DST >= IMM) { + insn += insn->off; + CONT_JMP; + } + CONT; + JMP_JLE_X: + if (DST <= SRC) { + insn += insn->off; + CONT_JMP; + } + CONT; + JMP_JLE_K: + if (DST <= IMM) { + insn += insn->off; + CONT_JMP; + } + CONT; + JMP_JSGT_X: + if (((s64) DST) > ((s64) SRC)) { + insn += insn->off; + CONT_JMP; + } + CONT; + JMP_JSGT_K: + if (((s64) DST) > ((s64) IMM)) { + insn += insn->off; + CONT_JMP; + } + CONT; + JMP_JSLT_X: + if (((s64) DST) < ((s64) SRC)) { + insn += insn->off; + CONT_JMP; + } + CONT; + JMP_JSLT_K: + if (((s64) DST) < ((s64) IMM)) { + insn += insn->off; + CONT_JMP; + } + CONT; + JMP_JSGE_X: + if (((s64) DST) >= ((s64) SRC)) { + insn += insn->off; + CONT_JMP; + } + CONT; + JMP_JSGE_K: + if (((s64) DST) >= ((s64) IMM)) { + insn += insn->off; + CONT_JMP; + } + CONT; + JMP_JSLE_X: + if (((s64) DST) <= ((s64) SRC)) { + insn += insn->off; + CONT_JMP; + } + CONT; + JMP_JSLE_K: + if (((s64) DST) <= ((s64) IMM)) { + insn += insn->off; + CONT_JMP; + } + CONT; + JMP_JSET_X: + if (DST & SRC) { + insn += insn->off; + CONT_JMP; + } + CONT; + JMP_JSET_K: + if (DST & IMM) { + insn += insn->off; + CONT_JMP; + } + CONT; + JMP_EXIT: + return BPF_R0; + + /* ST, STX and LDX*/ + ST_NOSPEC: + /* Speculation barrier for mitigating Speculative Store Bypass. + * In case of arm64, we rely on the firmware mitigation as + * controlled via the ssbd kernel parameter. Whenever the + * mitigation is enabled, it works for all of the kernel code + * with no need to provide any additional instructions here. + * In case of x86, we use 'lfence' insn for mitigation. We + * reuse preexisting logic from Spectre v1 mitigation that + * happens to produce the required code on x86 for v4 as well. + */ +#ifdef CONFIG_X86 + barrier_nospec(); +#endif + CONT; +#define LDST(SIZEOP, SIZE) \ + STX_MEM_##SIZEOP: \ + *(SIZE *)(unsigned long) (DST + insn->off) = SRC; \ + CONT; \ + ST_MEM_##SIZEOP: \ + *(SIZE *)(unsigned long) (DST + insn->off) = IMM; \ + CONT; \ + LDX_MEM_##SIZEOP: \ + DST = *(SIZE *)(unsigned long) (SRC + insn->off); \ + CONT; + + LDST(B, u8) + LDST(H, u16) + LDST(W, u32) + LDST(DW, u64) +#undef LDST + STX_XADD_W: /* lock xadd *(u32 *)(dst_reg + off16) += src_reg */ + atomic_add((u32) SRC, (atomic_t *)(unsigned long) + (DST + insn->off)); + CONT; + STX_XADD_DW: /* lock xadd *(u64 *)(dst_reg + off16) += src_reg */ + atomic64_add((u64) SRC, (atomic64_t *)(unsigned long) + (DST + insn->off)); + CONT; + + default_label: + /* If we ever reach this, we have a bug somewhere. Die hard here + * instead of just returning 0; we could be somewhere in a subprog, + * so execution could continue otherwise which we do /not/ want. + * + * Note, verifier whitelists all opcodes in bpf_opcode_in_insntable(). + */ + pr_warn("BPF interpreter: unknown opcode %02x\n", insn->code); + BUG_ON(1); + return 0; +} +STACK_FRAME_NON_STANDARD(___bpf_prog_run); /* jump table */ + +#define PROG_NAME(stack_size) __bpf_prog_run##stack_size +#define DEFINE_BPF_PROG_RUN(stack_size) \ +static unsigned int PROG_NAME(stack_size)(const void *ctx, const struct bpf_insn *insn) \ +{ \ + u64 stack[stack_size / sizeof(u64)]; \ + u64 regs[MAX_BPF_EXT_REG]; \ +\ + FP = (u64) (unsigned long) &stack[ARRAY_SIZE(stack)]; \ + ARG1 = (u64) (unsigned long) ctx; \ + return ___bpf_prog_run(regs, insn, stack); \ +} + +#define PROG_NAME_ARGS(stack_size) __bpf_prog_run_args##stack_size +#define DEFINE_BPF_PROG_RUN_ARGS(stack_size) \ +static u64 PROG_NAME_ARGS(stack_size)(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5, \ + const struct bpf_insn *insn) \ +{ \ + u64 stack[stack_size / sizeof(u64)]; \ + u64 regs[MAX_BPF_EXT_REG]; \ +\ + FP = (u64) (unsigned long) &stack[ARRAY_SIZE(stack)]; \ + BPF_R1 = r1; \ + BPF_R2 = r2; \ + BPF_R3 = r3; \ + BPF_R4 = r4; \ + BPF_R5 = r5; \ + return ___bpf_prog_run(regs, insn, stack); \ +} + +#define EVAL1(FN, X) FN(X) +#define EVAL2(FN, X, Y...) FN(X) EVAL1(FN, Y) +#define EVAL3(FN, X, Y...) FN(X) EVAL2(FN, Y) +#define EVAL4(FN, X, Y...) FN(X) EVAL3(FN, Y) +#define EVAL5(FN, X, Y...) FN(X) EVAL4(FN, Y) +#define EVAL6(FN, X, Y...) FN(X) EVAL5(FN, Y) + +EVAL6(DEFINE_BPF_PROG_RUN, 32, 64, 96, 128, 160, 192); +EVAL6(DEFINE_BPF_PROG_RUN, 224, 256, 288, 320, 352, 384); +EVAL4(DEFINE_BPF_PROG_RUN, 416, 448, 480, 512); + +EVAL6(DEFINE_BPF_PROG_RUN_ARGS, 32, 64, 96, 128, 160, 192); +EVAL6(DEFINE_BPF_PROG_RUN_ARGS, 224, 256, 288, 320, 352, 384); +EVAL4(DEFINE_BPF_PROG_RUN_ARGS, 416, 448, 480, 512); + +#define PROG_NAME_LIST(stack_size) PROG_NAME(stack_size), + +static unsigned int (*interpreters[])(const void *ctx, + const struct bpf_insn *insn) = { +EVAL6(PROG_NAME_LIST, 32, 64, 96, 128, 160, 192) +EVAL6(PROG_NAME_LIST, 224, 256, 288, 320, 352, 384) +EVAL4(PROG_NAME_LIST, 416, 448, 480, 512) +}; +#undef PROG_NAME_LIST +#define PROG_NAME_LIST(stack_size) PROG_NAME_ARGS(stack_size), +static u64 (*interpreters_args[])(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5, + const struct bpf_insn *insn) = { +EVAL6(PROG_NAME_LIST, 32, 64, 96, 128, 160, 192) +EVAL6(PROG_NAME_LIST, 224, 256, 288, 320, 352, 384) +EVAL4(PROG_NAME_LIST, 416, 448, 480, 512) +}; +#undef PROG_NAME_LIST + +void bpf_patch_call_args(struct bpf_insn *insn, u32 stack_depth) +{ + stack_depth = max_t(u32, stack_depth, 1); + insn->off = (s16) insn->imm; + insn->imm = interpreters_args[(round_up(stack_depth, 32) / 32) - 1] - + __bpf_call_base_args; + insn->code = BPF_JMP | BPF_CALL_ARGS; +} + +#else +static unsigned int __bpf_prog_ret0_warn(const void *ctx, + const struct bpf_insn *insn) +{ + /* If this handler ever gets executed, then BPF_JIT_ALWAYS_ON + * is not working properly, so warn about it! + */ + WARN_ON_ONCE(1); + return 0; +} +#endif + +bool bpf_prog_array_compatible(struct bpf_array *array, + const struct bpf_prog *fp) +{ + if (fp->kprobe_override) + return false; + + if (!array->owner_prog_type) { + /* There's no owner yet where we could check for + * compatibility. + */ + array->owner_prog_type = fp->type; + array->owner_jited = fp->jited; + + return true; + } + + return array->owner_prog_type == fp->type && + array->owner_jited == fp->jited; +} + +static int bpf_check_tail_call(const struct bpf_prog *fp) +{ + struct bpf_prog_aux *aux = fp->aux; + int i; + + for (i = 0; i < aux->used_map_cnt; i++) { + struct bpf_map *map = aux->used_maps[i]; + struct bpf_array *array; + + if (map->map_type != BPF_MAP_TYPE_PROG_ARRAY) + continue; + + array = container_of(map, struct bpf_array, map); + if (!bpf_prog_array_compatible(array, fp)) + return -EINVAL; + } + + return 0; +} + +static void bpf_prog_select_func(struct bpf_prog *fp) +{ +#ifndef CONFIG_BPF_JIT_ALWAYS_ON + u32 stack_depth = max_t(u32, fp->aux->stack_depth, 1); + + fp->bpf_func = interpreters[(round_up(stack_depth, 32) / 32) - 1]; +#else + fp->bpf_func = __bpf_prog_ret0_warn; +#endif +} + +/** + * bpf_prog_select_runtime - select exec runtime for BPF program + * @fp: bpf_prog populated with internal BPF program + * @err: pointer to error variable + * + * Try to JIT eBPF program, if JIT is not available, use interpreter. + * The BPF program will be executed via BPF_PROG_RUN() macro. + */ +struct bpf_prog *bpf_prog_select_runtime(struct bpf_prog *fp, int *err) +{ + /* In case of BPF to BPF calls, verifier did all the prep + * work with regards to JITing, etc. + */ + if (fp->bpf_func) + goto finalize; + + bpf_prog_select_func(fp); + + /* eBPF JITs can rewrite the program in case constant + * blinding is active. However, in case of error during + * blinding, bpf_int_jit_compile() must always return a + * valid program, which in this case would simply not + * be JITed, but falls back to the interpreter. + */ + if (!bpf_prog_is_dev_bound(fp->aux)) { + fp = bpf_int_jit_compile(fp); +#ifdef CONFIG_BPF_JIT_ALWAYS_ON + if (!fp->jited) { + *err = -ENOTSUPP; + return fp; + } +#endif + } else { + *err = bpf_prog_offload_compile(fp); + if (*err) + return fp; + } + +finalize: + bpf_prog_lock_ro(fp); + + /* The tail call compatibility check can only be done at + * this late stage as we need to determine, if we deal + * with JITed or non JITed program concatenations and not + * all eBPF JITs might immediately support all features. + */ + *err = bpf_check_tail_call(fp); + + return fp; +} +EXPORT_SYMBOL_GPL(bpf_prog_select_runtime); + +static unsigned int __bpf_prog_ret1(const void *ctx, + const struct bpf_insn *insn) +{ + return 1; +} + +static struct bpf_prog_dummy { + struct bpf_prog prog; +} dummy_bpf_prog = { + .prog = { + .bpf_func = __bpf_prog_ret1, + }, +}; + +/* to avoid allocating empty bpf_prog_array for cgroups that + * don't have bpf program attached use one global 'empty_prog_array' + * It will not be modified the caller of bpf_prog_array_alloc() + * (since caller requested prog_cnt == 0) + * that pointer should be 'freed' by bpf_prog_array_free() + */ +static struct { + struct bpf_prog_array hdr; + struct bpf_prog *null_prog; +} empty_prog_array = { + .null_prog = NULL, +}; + +struct bpf_prog_array *bpf_prog_array_alloc(u32 prog_cnt, gfp_t flags) +{ + if (prog_cnt) + return kzalloc(sizeof(struct bpf_prog_array) + + sizeof(struct bpf_prog_array_item) * + (prog_cnt + 1), + flags); + + return &empty_prog_array.hdr; +} + +void bpf_prog_array_free(struct bpf_prog_array __rcu *progs) +{ + if (!progs || + progs == (struct bpf_prog_array __rcu *)&empty_prog_array.hdr) + return; + kfree_rcu(progs, rcu); +} + +int bpf_prog_array_length(struct bpf_prog_array __rcu *array) +{ + struct bpf_prog_array_item *item; + u32 cnt = 0; + + rcu_read_lock(); + item = rcu_dereference(array)->items; + for (; item->prog; item++) + if (item->prog != &dummy_bpf_prog.prog) + cnt++; + rcu_read_unlock(); + return cnt; +} + + +static bool bpf_prog_array_copy_core(struct bpf_prog_array __rcu *array, + u32 *prog_ids, + u32 request_cnt) +{ + struct bpf_prog_array_item *item; + int i = 0; + + item = rcu_dereference_check(array, 1)->items; + for (; item->prog; item++) { + if (item->prog == &dummy_bpf_prog.prog) + continue; + prog_ids[i] = item->prog->aux->id; + if (++i == request_cnt) { + item++; + break; + } + } + + return !!(item->prog); +} + +int bpf_prog_array_copy_to_user(struct bpf_prog_array __rcu *array, + __u32 __user *prog_ids, u32 cnt) +{ + unsigned long err = 0; + bool nospc; + u32 *ids; + + /* users of this function are doing: + * cnt = bpf_prog_array_length(); + * if (cnt > 0) + * bpf_prog_array_copy_to_user(..., cnt); + * so below kcalloc doesn't need extra cnt > 0 check, but + * bpf_prog_array_length() releases rcu lock and + * prog array could have been swapped with empty or larger array, + * so always copy 'cnt' prog_ids to the user. + * In a rare race the user will see zero prog_ids + */ + ids = kcalloc(cnt, sizeof(u32), GFP_USER | __GFP_NOWARN); + if (!ids) + return -ENOMEM; + rcu_read_lock(); + nospc = bpf_prog_array_copy_core(array, ids, cnt); + rcu_read_unlock(); + err = copy_to_user(prog_ids, ids, cnt * sizeof(u32)); + kfree(ids); + if (err) + return -EFAULT; + if (nospc) + return -ENOSPC; + return 0; +} + +void bpf_prog_array_delete_safe(struct bpf_prog_array __rcu *array, + struct bpf_prog *old_prog) +{ + struct bpf_prog_array_item *item = array->items; + + for (; item->prog; item++) + if (item->prog == old_prog) { + WRITE_ONCE(item->prog, &dummy_bpf_prog.prog); + break; + } +} + +int bpf_prog_array_copy(struct bpf_prog_array __rcu *old_array, + struct bpf_prog *exclude_prog, + struct bpf_prog *include_prog, + struct bpf_prog_array **new_array) +{ + int new_prog_cnt, carry_prog_cnt = 0; + struct bpf_prog_array_item *existing; + struct bpf_prog_array *array; + bool found_exclude = false; + int new_prog_idx = 0; + + /* Figure out how many existing progs we need to carry over to + * the new array. + */ + if (old_array) { + existing = old_array->items; + for (; existing->prog; existing++) { + if (existing->prog == exclude_prog) { + found_exclude = true; + continue; + } + if (existing->prog != &dummy_bpf_prog.prog) + carry_prog_cnt++; + if (existing->prog == include_prog) + return -EEXIST; + } + } + + if (exclude_prog && !found_exclude) + return -ENOENT; + + /* How many progs (not NULL) will be in the new array? */ + new_prog_cnt = carry_prog_cnt; + if (include_prog) + new_prog_cnt += 1; + + /* Do we have any prog (not NULL) in the new array? */ + if (!new_prog_cnt) { + *new_array = NULL; + return 0; + } + + /* +1 as the end of prog_array is marked with NULL */ + array = bpf_prog_array_alloc(new_prog_cnt + 1, GFP_KERNEL); + if (!array) + return -ENOMEM; + + /* Fill in the new prog array */ + if (carry_prog_cnt) { + existing = old_array->items; + for (; existing->prog; existing++) + if (existing->prog != exclude_prog && + existing->prog != &dummy_bpf_prog.prog) { + array->items[new_prog_idx++].prog = + existing->prog; + } + } + if (include_prog) + array->items[new_prog_idx++].prog = include_prog; + array->items[new_prog_idx].prog = NULL; + *new_array = array; + return 0; +} + +int bpf_prog_array_copy_info(struct bpf_prog_array __rcu *array, + u32 *prog_ids, u32 request_cnt, + u32 *prog_cnt) +{ + u32 cnt = 0; + + if (array) + cnt = bpf_prog_array_length(array); + + *prog_cnt = cnt; + + /* return early if user requested only program count or nothing to copy */ + if (!request_cnt || !cnt) + return 0; + + /* this function is called under trace/bpf_trace.c: bpf_event_mutex */ + return bpf_prog_array_copy_core(array, prog_ids, request_cnt) ? -ENOSPC + : 0; +} + +static void bpf_prog_free_deferred(struct work_struct *work) +{ + struct bpf_prog_aux *aux; + int i; + + aux = container_of(work, struct bpf_prog_aux, work); + if (bpf_prog_is_dev_bound(aux)) + bpf_prog_offload_destroy(aux->prog); +#ifdef CONFIG_PERF_EVENTS + if (aux->prog->has_callchain_buf) + put_callchain_buffers(); +#endif + for (i = 0; i < aux->func_cnt; i++) + bpf_jit_free(aux->func[i]); + if (aux->func_cnt) { + kfree(aux->func); + bpf_prog_unlock_free(aux->prog); + } else { + bpf_jit_free(aux->prog); + } +} + +/* Free internal BPF program */ +void bpf_prog_free(struct bpf_prog *fp) +{ + struct bpf_prog_aux *aux = fp->aux; + + INIT_WORK(&aux->work, bpf_prog_free_deferred); + schedule_work(&aux->work); +} +EXPORT_SYMBOL_GPL(bpf_prog_free); + +/* RNG for unpriviledged user space with separated state from prandom_u32(). */ +static DEFINE_PER_CPU(struct rnd_state, bpf_user_rnd_state); + +void bpf_user_rnd_init_once(void) +{ + prandom_init_once(&bpf_user_rnd_state); +} + +BPF_CALL_0(bpf_user_rnd_u32) +{ + /* Should someone ever have the rather unwise idea to use some + * of the registers passed into this function, then note that + * this function is called from native eBPF and classic-to-eBPF + * transformations. Register assignments from both sides are + * different, f.e. classic always sets fn(ctx, A, X) here. + */ + struct rnd_state *state; + u32 res; + + state = &get_cpu_var(bpf_user_rnd_state); + res = prandom_u32_state(state); + put_cpu_var(bpf_user_rnd_state); + + return res; +} + +/* Weak definitions of helper functions in case we don't have bpf syscall. */ +const struct bpf_func_proto bpf_map_lookup_elem_proto __weak; +const struct bpf_func_proto bpf_map_update_elem_proto __weak; +const struct bpf_func_proto bpf_map_delete_elem_proto __weak; + +const struct bpf_func_proto bpf_get_prandom_u32_proto __weak; +const struct bpf_func_proto bpf_get_smp_processor_id_proto __weak; +const struct bpf_func_proto bpf_get_numa_node_id_proto __weak; +const struct bpf_func_proto bpf_ktime_get_ns_proto __weak; + +const struct bpf_func_proto bpf_get_current_pid_tgid_proto __weak; +const struct bpf_func_proto bpf_get_current_uid_gid_proto __weak; +const struct bpf_func_proto bpf_get_current_comm_proto __weak; +const struct bpf_func_proto bpf_sock_map_update_proto __weak; +const struct bpf_func_proto bpf_sock_hash_update_proto __weak; +const struct bpf_func_proto bpf_get_current_cgroup_id_proto __weak; +const struct bpf_func_proto bpf_get_local_storage_proto __weak; + +const struct bpf_func_proto * __weak bpf_get_trace_printk_proto(void) +{ + return NULL; +} + +u64 __weak +bpf_event_output(struct bpf_map *map, u64 flags, void *meta, u64 meta_size, + void *ctx, u64 ctx_size, bpf_ctx_copy_t ctx_copy) +{ + return -ENOTSUPP; +} +EXPORT_SYMBOL_GPL(bpf_event_output); + +/* Always built-in helper functions. */ +const struct bpf_func_proto bpf_tail_call_proto = { + .func = NULL, + .gpl_only = false, + .ret_type = RET_VOID, + .arg1_type = ARG_PTR_TO_CTX, + .arg2_type = ARG_CONST_MAP_PTR, + .arg3_type = ARG_ANYTHING, +}; + +/* Stub for JITs that only support cBPF. eBPF programs are interpreted. + * It is encouraged to implement bpf_int_jit_compile() instead, so that + * eBPF and implicitly also cBPF can get JITed! + */ +struct bpf_prog * __weak bpf_int_jit_compile(struct bpf_prog *prog) +{ + return prog; +} + +/* Stub for JITs that support eBPF. All cBPF code gets transformed into + * eBPF by the kernel and is later compiled by bpf_int_jit_compile(). + */ +void __weak bpf_jit_compile(struct bpf_prog *prog) +{ +} + +bool __weak bpf_helper_changes_pkt_data(void *func) +{ + return false; +} + +/* To execute LD_ABS/LD_IND instructions __bpf_prog_run() may call + * skb_copy_bits(), so provide a weak definition of it for NET-less config. + */ +int __weak skb_copy_bits(const struct sk_buff *skb, int offset, void *to, + int len) +{ + return -EFAULT; +} + +/* All definitions of tracepoints related to BPF. */ +#define CREATE_TRACE_POINTS +#include <linux/bpf_trace.h> + +EXPORT_TRACEPOINT_SYMBOL_GPL(xdp_exception); |