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Diffstat (limited to '')
| -rw-r--r-- | kernel/bpf/core.c | 2772 |
1 files changed, 2772 insertions, 0 deletions
diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c new file mode 100644 index 000000000..76bf1de26 --- /dev/null +++ b/kernel/bpf/core.c @@ -0,0 +1,2772 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * 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> + * + * Andi Kleen - Fix a few bad bugs and races. + * Kris Katterjohn - Added many additional checks in bpf_check_classic() + */ + +#include <uapi/linux/btf.h> +#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/btf.h> +#include <linux/objtool.h> +#include <linux/rbtree_latch.h> +#include <linux/kallsyms.h> +#include <linux/rcupdate.h> +#include <linux/perf_event.h> +#include <linux/extable.h> +#include <linux/log2.h> +#include <linux/bpf_verifier.h> +#include <linux/nodemask.h> +#include <linux/nospec.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) { + if (unlikely(!skb_mac_header_was_set(skb))) + return NULL; + 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_no_stats(unsigned int size, gfp_t gfp_extra_flags) +{ + gfp_t gfp_flags = GFP_KERNEL_ACCOUNT | __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); + if (fp == NULL) + return NULL; + + aux = kzalloc(sizeof(*aux), GFP_KERNEL_ACCOUNT | gfp_extra_flags); + if (aux == NULL) { + vfree(fp); + return NULL; + } + fp->active = alloc_percpu_gfp(int, GFP_KERNEL_ACCOUNT | gfp_extra_flags); + if (!fp->active) { + vfree(fp); + kfree(aux); + return NULL; + } + + fp->pages = size / PAGE_SIZE; + fp->aux = aux; + fp->aux->prog = fp; + fp->jit_requested = ebpf_jit_enabled(); + fp->blinding_requested = bpf_jit_blinding_enabled(fp); +#ifdef CONFIG_CGROUP_BPF + aux->cgroup_atype = CGROUP_BPF_ATTACH_TYPE_INVALID; +#endif + + INIT_LIST_HEAD_RCU(&fp->aux->ksym.lnode); + mutex_init(&fp->aux->used_maps_mutex); + mutex_init(&fp->aux->dst_mutex); + + return fp; +} + +struct bpf_prog *bpf_prog_alloc(unsigned int size, gfp_t gfp_extra_flags) +{ + gfp_t gfp_flags = GFP_KERNEL_ACCOUNT | __GFP_ZERO | gfp_extra_flags; + struct bpf_prog *prog; + int cpu; + + prog = bpf_prog_alloc_no_stats(size, gfp_extra_flags); + if (!prog) + return NULL; + + prog->stats = alloc_percpu_gfp(struct bpf_prog_stats, gfp_flags); + if (!prog->stats) { + free_percpu(prog->active); + kfree(prog->aux); + vfree(prog); + return NULL; + } + + for_each_possible_cpu(cpu) { + struct bpf_prog_stats *pstats; + + pstats = per_cpu_ptr(prog->stats, cpu); + u64_stats_init(&pstats->syncp); + } + return prog; +} +EXPORT_SYMBOL_GPL(bpf_prog_alloc); + +int bpf_prog_alloc_jited_linfo(struct bpf_prog *prog) +{ + if (!prog->aux->nr_linfo || !prog->jit_requested) + return 0; + + prog->aux->jited_linfo = kvcalloc(prog->aux->nr_linfo, + sizeof(*prog->aux->jited_linfo), + GFP_KERNEL_ACCOUNT | __GFP_NOWARN); + if (!prog->aux->jited_linfo) + return -ENOMEM; + + return 0; +} + +void bpf_prog_jit_attempt_done(struct bpf_prog *prog) +{ + if (prog->aux->jited_linfo && + (!prog->jited || !prog->aux->jited_linfo[0])) { + kvfree(prog->aux->jited_linfo); + prog->aux->jited_linfo = NULL; + } + + kfree(prog->aux->kfunc_tab); + prog->aux->kfunc_tab = NULL; +} + +/* The jit engine is responsible to provide an array + * for insn_off to the jited_off mapping (insn_to_jit_off). + * + * The idx to this array is the insn_off. Hence, the insn_off + * here is relative to the prog itself instead of the main prog. + * This array has one entry for each xlated bpf insn. + * + * jited_off is the byte off to the end of the jited insn. + * + * Hence, with + * insn_start: + * The first bpf insn off of the prog. The insn off + * here is relative to the main prog. + * e.g. if prog is a subprog, insn_start > 0 + * linfo_idx: + * The prog's idx to prog->aux->linfo and jited_linfo + * + * jited_linfo[linfo_idx] = prog->bpf_func + * + * For i > linfo_idx, + * + * jited_linfo[i] = prog->bpf_func + + * insn_to_jit_off[linfo[i].insn_off - insn_start - 1] + */ +void bpf_prog_fill_jited_linfo(struct bpf_prog *prog, + const u32 *insn_to_jit_off) +{ + u32 linfo_idx, insn_start, insn_end, nr_linfo, i; + const struct bpf_line_info *linfo; + void **jited_linfo; + + if (!prog->aux->jited_linfo) + /* Userspace did not provide linfo */ + return; + + linfo_idx = prog->aux->linfo_idx; + linfo = &prog->aux->linfo[linfo_idx]; + insn_start = linfo[0].insn_off; + insn_end = insn_start + prog->len; + + jited_linfo = &prog->aux->jited_linfo[linfo_idx]; + jited_linfo[0] = prog->bpf_func; + + nr_linfo = prog->aux->nr_linfo - linfo_idx; + + for (i = 1; i < nr_linfo && linfo[i].insn_off < insn_end; i++) + /* The verifier ensures that linfo[i].insn_off is + * strictly increasing + */ + jited_linfo[i] = prog->bpf_func + + insn_to_jit_off[linfo[i].insn_off - insn_start - 1]; +} + +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_ACCOUNT | __GFP_ZERO | gfp_extra_flags; + struct bpf_prog *fp; + u32 pages; + + size = round_up(size, PAGE_SIZE); + pages = size / PAGE_SIZE; + if (pages <= fp_old->pages) + return fp_old; + + fp = __vmalloc(size, gfp_flags); + if (fp) { + 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; + fp_old->stats = NULL; + fp_old->active = NULL; + __bpf_prog_free(fp_old); + } + + return fp; +} + +void __bpf_prog_free(struct bpf_prog *fp) +{ + if (fp->aux) { + mutex_destroy(&fp->aux->used_maps_mutex); + mutex_destroy(&fp->aux->dst_mutex); + kfree(fp->aux->poke_tab); + kfree(fp->aux); + } + free_percpu(fp->stats); + free_percpu(fp->active); + vfree(fp); +} + +int bpf_prog_calc_tag(struct bpf_prog *fp) +{ + const u32 bits_offset = SHA1_BLOCK_SIZE - sizeof(__be64); + u32 raw_size = bpf_prog_tag_scratch_size(fp); + u32 digest[SHA1_DIGEST_WORDS]; + u32 ws[SHA1_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; + + sha1_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 || + dst[i].src_reg == BPF_PSEUDO_MAP_VALUE)) { + 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, SHA1_BLOCK_SIZE); + blocks = bsize / SHA1_BLOCK_SIZE; + 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--) { + sha1_transform(digest, todo, ws); + todo += SHA1_BLOCK_SIZE; + } + + result = (__force __be32 *)digest; + for (i = 0; i < SHA1_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, s32 end_old, + s32 end_new, s32 curr, const bool probe_pass) +{ + const s64 imm_min = S32_MIN, imm_max = S32_MAX; + s32 delta = end_new - end_old; + s64 imm = insn->imm; + + if (curr < pos && curr + imm + 1 >= end_old) + imm += delta; + else if (curr >= end_new && curr + imm + 1 < end_new) + 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, s32 end_old, + s32 end_new, s32 curr, const bool probe_pass) +{ + s64 off_min, off_max, off; + s32 delta = end_new - end_old; + + if (insn->code == (BPF_JMP32 | BPF_JA)) { + off = insn->imm; + off_min = S32_MIN; + off_max = S32_MAX; + } else { + off = insn->off; + off_min = S16_MIN; + off_max = S16_MAX; + } + + if (curr < pos && curr + off + 1 >= end_old) + off += delta; + else if (curr >= end_new && curr + off + 1 < end_new) + off -= delta; + if (off < off_min || off > off_max) + return -ERANGE; + if (!probe_pass) { + if (insn->code == (BPF_JMP32 | BPF_JA)) + insn->imm = off; + else + insn->off = off; + } + return 0; +} + +static int bpf_adj_branches(struct bpf_prog *prog, u32 pos, s32 end_old, + s32 end_new, const bool probe_pass) +{ + u32 i, insn_cnt = prog->len + (probe_pass ? end_new - end_old : 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 = end_new; + insn = prog->insnsi + end_old; + } + if (bpf_pseudo_func(insn)) { + ret = bpf_adj_delta_to_imm(insn, pos, end_old, + end_new, i, probe_pass); + if (ret) + return ret; + continue; + } + code = insn->code; + if ((BPF_CLASS(code) != BPF_JMP && + BPF_CLASS(code) != BPF_JMP32) || + 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, end_old, + end_new, i, probe_pass); + } else { + ret = bpf_adj_delta_to_off(insn, pos, end_old, + end_new, i, probe_pass); + } + if (ret) + break; + } + + return ret; +} + +static void bpf_adj_linfo(struct bpf_prog *prog, u32 off, u32 delta) +{ + struct bpf_line_info *linfo; + u32 i, nr_linfo; + + nr_linfo = prog->aux->nr_linfo; + if (!nr_linfo || !delta) + return; + + linfo = prog->aux->linfo; + + for (i = 0; i < nr_linfo; i++) + if (off < linfo[i].insn_off) + break; + + /* Push all off < linfo[i].insn_off by delta */ + for (; i < nr_linfo; i++) + linfo[i].insn_off += delta; +} + +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; + int err; + + /* 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 && + (err = bpf_adj_branches(prog, off, off + 1, off + len, true))) + return ERR_PTR(err); + + /* 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 ERR_PTR(-ENOMEM); + + 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, off + 1, off + len, false)); + + bpf_adj_linfo(prog_adj, off, insn_delta); + + return prog_adj; +} + +int bpf_remove_insns(struct bpf_prog *prog, u32 off, u32 cnt) +{ + /* Branch offsets can't overflow when program is shrinking, no need + * to call bpf_adj_branches(..., true) here + */ + memmove(prog->insnsi + off, prog->insnsi + off + cnt, + sizeof(struct bpf_insn) * (prog->len - off - cnt)); + prog->len -= cnt; + + return WARN_ON_ONCE(bpf_adj_branches(prog, off, off + cnt, off, false)); +} + +static 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_DEFAULT_ON); +int bpf_jit_kallsyms __read_mostly = IS_BUILTIN(CONFIG_BPF_JIT_DEFAULT_ON); +int bpf_jit_harden __read_mostly; +long bpf_jit_limit __read_mostly; +long bpf_jit_limit_max __read_mostly; + +static void +bpf_prog_ksym_set_addr(struct bpf_prog *prog) +{ + WARN_ON_ONCE(!bpf_prog_ebpf_jited(prog)); + + prog->aux->ksym.start = (unsigned long) prog->bpf_func; + prog->aux->ksym.end = prog->aux->ksym.start + prog->jited_len; +} + +static void +bpf_prog_ksym_set_name(struct bpf_prog *prog) +{ + char *sym = prog->aux->ksym.name; + const char *end = sym + KSYM_NAME_LEN; + const struct btf_type *type; + const char *func_name; + + 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)); + + /* prog->aux->name will be ignored if full btf name is available */ + if (prog->aux->func_info_cnt) { + type = btf_type_by_id(prog->aux->btf, + prog->aux->func_info[prog->aux->func_idx].type_id); + func_name = btf_name_by_offset(prog->aux->btf, type->name_off); + snprintf(sym, (size_t)(end - sym), "_%s", func_name); + return; + } + + if (prog->aux->name[0]) + snprintf(sym, (size_t)(end - sym), "_%s", prog->aux->name); + else + *sym = 0; +} + +static unsigned long bpf_get_ksym_start(struct latch_tree_node *n) +{ + return container_of(n, struct bpf_ksym, tnode)->start; +} + +static __always_inline bool bpf_tree_less(struct latch_tree_node *a, + struct latch_tree_node *b) +{ + return bpf_get_ksym_start(a) < bpf_get_ksym_start(b); +} + +static __always_inline int bpf_tree_comp(void *key, struct latch_tree_node *n) +{ + unsigned long val = (unsigned long)key; + const struct bpf_ksym *ksym; + + ksym = container_of(n, struct bpf_ksym, tnode); + + if (val < ksym->start) + return -1; + /* Ensure that we detect return addresses as part of the program, when + * the final instruction is a call for a program part of the stack + * trace. Therefore, do val > ksym->end instead of val >= ksym->end. + */ + if (val > ksym->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; + +void bpf_ksym_add(struct bpf_ksym *ksym) +{ + spin_lock_bh(&bpf_lock); + WARN_ON_ONCE(!list_empty(&ksym->lnode)); + list_add_tail_rcu(&ksym->lnode, &bpf_kallsyms); + latch_tree_insert(&ksym->tnode, &bpf_tree, &bpf_tree_ops); + spin_unlock_bh(&bpf_lock); +} + +static void __bpf_ksym_del(struct bpf_ksym *ksym) +{ + if (list_empty(&ksym->lnode)) + return; + + latch_tree_erase(&ksym->tnode, &bpf_tree, &bpf_tree_ops); + list_del_rcu(&ksym->lnode); +} + +void bpf_ksym_del(struct bpf_ksym *ksym) +{ + spin_lock_bh(&bpf_lock); + __bpf_ksym_del(ksym); + spin_unlock_bh(&bpf_lock); +} + +static bool bpf_prog_kallsyms_candidate(const struct bpf_prog *fp) +{ + return fp->jited && !bpf_prog_was_classic(fp); +} + +void bpf_prog_kallsyms_add(struct bpf_prog *fp) +{ + if (!bpf_prog_kallsyms_candidate(fp) || + !bpf_capable()) + return; + + bpf_prog_ksym_set_addr(fp); + bpf_prog_ksym_set_name(fp); + fp->aux->ksym.prog = true; + + bpf_ksym_add(&fp->aux->ksym); +} + +void bpf_prog_kallsyms_del(struct bpf_prog *fp) +{ + if (!bpf_prog_kallsyms_candidate(fp)) + return; + + bpf_ksym_del(&fp->aux->ksym); +} + +static struct bpf_ksym *bpf_ksym_find(unsigned long addr) +{ + struct latch_tree_node *n; + + n = latch_tree_find((void *)addr, &bpf_tree, &bpf_tree_ops); + return n ? container_of(n, struct bpf_ksym, tnode) : NULL; +} + +const char *__bpf_address_lookup(unsigned long addr, unsigned long *size, + unsigned long *off, char *sym) +{ + struct bpf_ksym *ksym; + char *ret = NULL; + + rcu_read_lock(); + ksym = bpf_ksym_find(addr); + if (ksym) { + unsigned long symbol_start = ksym->start; + unsigned long symbol_end = ksym->end; + + strncpy(sym, ksym->name, KSYM_NAME_LEN); + + 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_ksym_find(addr) != NULL; + rcu_read_unlock(); + + return ret; +} + +static struct bpf_prog *bpf_prog_ksym_find(unsigned long addr) +{ + struct bpf_ksym *ksym = bpf_ksym_find(addr); + + return ksym && ksym->prog ? + container_of(ksym, struct bpf_prog_aux, ksym)->prog : + NULL; +} + +const struct exception_table_entry *search_bpf_extables(unsigned long addr) +{ + const struct exception_table_entry *e = NULL; + struct bpf_prog *prog; + + rcu_read_lock(); + prog = bpf_prog_ksym_find(addr); + if (!prog) + goto out; + if (!prog->aux->num_exentries) + goto out; + + e = search_extable(prog->aux->extable, prog->aux->num_exentries, addr); +out: + rcu_read_unlock(); + return e; +} + +int bpf_get_kallsym(unsigned int symnum, unsigned long *value, char *type, + char *sym) +{ + struct bpf_ksym *ksym; + unsigned int it = 0; + int ret = -ERANGE; + + if (!bpf_jit_kallsyms_enabled()) + return ret; + + rcu_read_lock(); + list_for_each_entry_rcu(ksym, &bpf_kallsyms, lnode) { + if (it++ != symnum) + continue; + + strncpy(sym, ksym->name, KSYM_NAME_LEN); + + *value = ksym->start; + *type = BPF_SYM_ELF_TYPE; + + ret = 0; + break; + } + rcu_read_unlock(); + + return ret; +} + +int bpf_jit_add_poke_descriptor(struct bpf_prog *prog, + struct bpf_jit_poke_descriptor *poke) +{ + struct bpf_jit_poke_descriptor *tab = prog->aux->poke_tab; + static const u32 poke_tab_max = 1024; + u32 slot = prog->aux->size_poke_tab; + u32 size = slot + 1; + + if (size > poke_tab_max) + return -ENOSPC; + if (poke->tailcall_target || poke->tailcall_target_stable || + poke->tailcall_bypass || poke->adj_off || poke->bypass_addr) + return -EINVAL; + + switch (poke->reason) { + case BPF_POKE_REASON_TAIL_CALL: + if (!poke->tail_call.map) + return -EINVAL; + break; + default: + return -EINVAL; + } + + tab = krealloc(tab, size * sizeof(*poke), GFP_KERNEL); + if (!tab) + return -ENOMEM; + + memcpy(&tab[slot], poke, sizeof(*poke)); + prog->aux->size_poke_tab = size; + prog->aux->poke_tab = tab; + + return slot; +} + +/* + * BPF program pack allocator. + * + * Most BPF programs are pretty small. Allocating a hole page for each + * program is sometime a waste. Many small bpf program also adds pressure + * to instruction TLB. To solve this issue, we introduce a BPF program pack + * allocator. The prog_pack allocator uses HPAGE_PMD_SIZE page (2MB on x86) + * to host BPF programs. + */ +#define BPF_PROG_CHUNK_SHIFT 6 +#define BPF_PROG_CHUNK_SIZE (1 << BPF_PROG_CHUNK_SHIFT) +#define BPF_PROG_CHUNK_MASK (~(BPF_PROG_CHUNK_SIZE - 1)) + +struct bpf_prog_pack { + struct list_head list; + void *ptr; + unsigned long bitmap[]; +}; + +void bpf_jit_fill_hole_with_zero(void *area, unsigned int size) +{ + memset(area, 0, size); +} + +#define BPF_PROG_SIZE_TO_NBITS(size) (round_up(size, BPF_PROG_CHUNK_SIZE) / BPF_PROG_CHUNK_SIZE) + +static DEFINE_MUTEX(pack_mutex); +static LIST_HEAD(pack_list); + +/* PMD_SIZE is not available in some special config, e.g. ARCH=arm with + * CONFIG_MMU=n. Use PAGE_SIZE in these cases. + */ +#ifdef PMD_SIZE +#define BPF_PROG_PACK_SIZE (PMD_SIZE * num_possible_nodes()) +#else +#define BPF_PROG_PACK_SIZE PAGE_SIZE +#endif + +#define BPF_PROG_CHUNK_COUNT (BPF_PROG_PACK_SIZE / BPF_PROG_CHUNK_SIZE) + +static struct bpf_prog_pack *alloc_new_pack(bpf_jit_fill_hole_t bpf_fill_ill_insns) +{ + struct bpf_prog_pack *pack; + + pack = kzalloc(struct_size(pack, bitmap, BITS_TO_LONGS(BPF_PROG_CHUNK_COUNT)), + GFP_KERNEL); + if (!pack) + return NULL; + pack->ptr = module_alloc(BPF_PROG_PACK_SIZE); + if (!pack->ptr) { + kfree(pack); + return NULL; + } + bpf_fill_ill_insns(pack->ptr, BPF_PROG_PACK_SIZE); + bitmap_zero(pack->bitmap, BPF_PROG_PACK_SIZE / BPF_PROG_CHUNK_SIZE); + list_add_tail(&pack->list, &pack_list); + + set_vm_flush_reset_perms(pack->ptr); + set_memory_ro((unsigned long)pack->ptr, BPF_PROG_PACK_SIZE / PAGE_SIZE); + set_memory_x((unsigned long)pack->ptr, BPF_PROG_PACK_SIZE / PAGE_SIZE); + return pack; +} + +void *bpf_prog_pack_alloc(u32 size, bpf_jit_fill_hole_t bpf_fill_ill_insns) +{ + unsigned int nbits = BPF_PROG_SIZE_TO_NBITS(size); + struct bpf_prog_pack *pack; + unsigned long pos; + void *ptr = NULL; + + mutex_lock(&pack_mutex); + if (size > BPF_PROG_PACK_SIZE) { + size = round_up(size, PAGE_SIZE); + ptr = module_alloc(size); + if (ptr) { + bpf_fill_ill_insns(ptr, size); + set_vm_flush_reset_perms(ptr); + set_memory_ro((unsigned long)ptr, size / PAGE_SIZE); + set_memory_x((unsigned long)ptr, size / PAGE_SIZE); + } + goto out; + } + list_for_each_entry(pack, &pack_list, list) { + pos = bitmap_find_next_zero_area(pack->bitmap, BPF_PROG_CHUNK_COUNT, 0, + nbits, 0); + if (pos < BPF_PROG_CHUNK_COUNT) + goto found_free_area; + } + + pack = alloc_new_pack(bpf_fill_ill_insns); + if (!pack) + goto out; + + pos = 0; + +found_free_area: + bitmap_set(pack->bitmap, pos, nbits); + ptr = (void *)(pack->ptr) + (pos << BPF_PROG_CHUNK_SHIFT); + +out: + mutex_unlock(&pack_mutex); + return ptr; +} + +void bpf_prog_pack_free(struct bpf_binary_header *hdr) +{ + struct bpf_prog_pack *pack = NULL, *tmp; + unsigned int nbits; + unsigned long pos; + + mutex_lock(&pack_mutex); + if (hdr->size > BPF_PROG_PACK_SIZE) { + module_memfree(hdr); + goto out; + } + + list_for_each_entry(tmp, &pack_list, list) { + if ((void *)hdr >= tmp->ptr && (tmp->ptr + BPF_PROG_PACK_SIZE) > (void *)hdr) { + pack = tmp; + break; + } + } + + if (WARN_ONCE(!pack, "bpf_prog_pack bug\n")) + goto out; + + nbits = BPF_PROG_SIZE_TO_NBITS(hdr->size); + pos = ((unsigned long)hdr - (unsigned long)pack->ptr) >> BPF_PROG_CHUNK_SHIFT; + + WARN_ONCE(bpf_arch_text_invalidate(hdr, hdr->size), + "bpf_prog_pack bug: missing bpf_arch_text_invalidate?\n"); + + bitmap_clear(pack->bitmap, pos, nbits); + if (bitmap_find_next_zero_area(pack->bitmap, BPF_PROG_CHUNK_COUNT, 0, + BPF_PROG_CHUNK_COUNT, 0) == 0) { + list_del(&pack->list); + module_memfree(pack->ptr); + kfree(pack); + } +out: + mutex_unlock(&pack_mutex); +} + +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 >> 1, + PAGE_SIZE), LONG_MAX); + return 0; +} +pure_initcall(bpf_jit_charge_init); + +int bpf_jit_charge_modmem(u32 size) +{ + if (atomic_long_add_return(size, &bpf_jit_current) > READ_ONCE(bpf_jit_limit)) { + if (!bpf_capable()) { + atomic_long_sub(size, &bpf_jit_current); + return -EPERM; + } + } + + return 0; +} + +void bpf_jit_uncharge_modmem(u32 size) +{ + atomic_long_sub(size, &bpf_jit_current); +} + +void *__weak bpf_jit_alloc_exec(unsigned long size) +{ + return module_alloc(size); +} + +void __weak bpf_jit_free_exec(void *addr) +{ + module_memfree(addr); +} + +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; + + WARN_ON_ONCE(!is_power_of_2(alignment) || + alignment > BPF_IMAGE_ALIGNMENT); + + /* 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); + + if (bpf_jit_charge_modmem(size)) + return NULL; + hdr = bpf_jit_alloc_exec(size); + if (!hdr) { + bpf_jit_uncharge_modmem(size); + return NULL; + } + + /* Fill space with illegal/arch-dep instructions. */ + bpf_fill_ill_insns(hdr, size); + + hdr->size = size; + hole = min_t(unsigned int, size - (proglen + sizeof(*hdr)), + PAGE_SIZE - sizeof(*hdr)); + start = prandom_u32_max(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 size = hdr->size; + + bpf_jit_free_exec(hdr); + bpf_jit_uncharge_modmem(size); +} + +/* Allocate jit binary from bpf_prog_pack allocator. + * Since the allocated memory is RO+X, the JIT engine cannot write directly + * to the memory. To solve this problem, a RW buffer is also allocated at + * as the same time. The JIT engine should calculate offsets based on the + * RO memory address, but write JITed program to the RW buffer. Once the + * JIT engine finishes, it calls bpf_jit_binary_pack_finalize, which copies + * the JITed program to the RO memory. + */ +struct bpf_binary_header * +bpf_jit_binary_pack_alloc(unsigned int proglen, u8 **image_ptr, + unsigned int alignment, + struct bpf_binary_header **rw_header, + u8 **rw_image, + bpf_jit_fill_hole_t bpf_fill_ill_insns) +{ + struct bpf_binary_header *ro_header; + u32 size, hole, start; + + WARN_ON_ONCE(!is_power_of_2(alignment) || + alignment > BPF_IMAGE_ALIGNMENT); + + /* add 16 bytes for a random section of illegal instructions */ + size = round_up(proglen + sizeof(*ro_header) + 16, BPF_PROG_CHUNK_SIZE); + + if (bpf_jit_charge_modmem(size)) + return NULL; + ro_header = bpf_prog_pack_alloc(size, bpf_fill_ill_insns); + if (!ro_header) { + bpf_jit_uncharge_modmem(size); + return NULL; + } + + *rw_header = kvmalloc(size, GFP_KERNEL); + if (!*rw_header) { + bpf_arch_text_copy(&ro_header->size, &size, sizeof(size)); + bpf_prog_pack_free(ro_header); + bpf_jit_uncharge_modmem(size); + return NULL; + } + + /* Fill space with illegal/arch-dep instructions. */ + bpf_fill_ill_insns(*rw_header, size); + (*rw_header)->size = size; + + hole = min_t(unsigned int, size - (proglen + sizeof(*ro_header)), + BPF_PROG_CHUNK_SIZE - sizeof(*ro_header)); + start = prandom_u32_max(hole) & ~(alignment - 1); + + *image_ptr = &ro_header->image[start]; + *rw_image = &(*rw_header)->image[start]; + + return ro_header; +} + +/* Copy JITed text from rw_header to its final location, the ro_header. */ +int bpf_jit_binary_pack_finalize(struct bpf_prog *prog, + struct bpf_binary_header *ro_header, + struct bpf_binary_header *rw_header) +{ + void *ptr; + + ptr = bpf_arch_text_copy(ro_header, rw_header, rw_header->size); + + kvfree(rw_header); + + if (IS_ERR(ptr)) { + bpf_prog_pack_free(ro_header); + return PTR_ERR(ptr); + } + return 0; +} + +/* bpf_jit_binary_pack_free is called in two different scenarios: + * 1) when the program is freed after; + * 2) when the JIT engine fails (before bpf_jit_binary_pack_finalize). + * For case 2), we need to free both the RO memory and the RW buffer. + * + * bpf_jit_binary_pack_free requires proper ro_header->size. However, + * bpf_jit_binary_pack_alloc does not set it. Therefore, ro_header->size + * must be set with either bpf_jit_binary_pack_finalize (normal path) or + * bpf_arch_text_copy (when jit fails). + */ +void bpf_jit_binary_pack_free(struct bpf_binary_header *ro_header, + struct bpf_binary_header *rw_header) +{ + u32 size = ro_header->size; + + bpf_prog_pack_free(ro_header); + kvfree(rw_header); + bpf_jit_uncharge_modmem(size); +} + +struct bpf_binary_header * +bpf_jit_binary_pack_hdr(const struct bpf_prog *fp) +{ + unsigned long real_start = (unsigned long)fp->bpf_func; + unsigned long addr; + + addr = real_start & BPF_PROG_CHUNK_MASK; + return (void *)addr; +} + +static inline struct bpf_binary_header * +bpf_jit_binary_hdr(const struct bpf_prog *fp) +{ + unsigned long real_start = (unsigned long)fp->bpf_func; + unsigned long addr; + + addr = real_start & PAGE_MASK; + return (void *)addr; +} + +/* 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_free(hdr); + WARN_ON_ONCE(!bpf_prog_kallsyms_verify_off(fp)); + } + + bpf_prog_unlock_free(fp); +} + +int bpf_jit_get_func_addr(const struct bpf_prog *prog, + const struct bpf_insn *insn, bool extra_pass, + u64 *func_addr, bool *func_addr_fixed) +{ + s16 off = insn->off; + s32 imm = insn->imm; + u8 *addr; + + *func_addr_fixed = insn->src_reg != BPF_PSEUDO_CALL; + if (!*func_addr_fixed) { + /* Place-holder address till the last pass has collected + * all addresses for JITed subprograms in which case we + * can pick them up from prog->aux. + */ + if (!extra_pass) + addr = NULL; + else if (prog->aux->func && + off >= 0 && off < prog->aux->func_cnt) + addr = (u8 *)prog->aux->func[off]->bpf_func; + else + return -EINVAL; + } else { + /* Address of a BPF helper call. Since part of the core + * kernel, it's always at a fixed location. __bpf_call_base + * and the helper with imm relative to it are both in core + * kernel. + */ + addr = (u8 *)__bpf_call_base + imm; + } + + *func_addr = (unsigned long)addr; + return 0; +} + +static int bpf_jit_blind_insn(const struct bpf_insn *from, + const struct bpf_insn *aux, + struct bpf_insn *to_buff, + bool emit_zext) +{ + struct bpf_insn *to = to_buff; + u32 imm_rnd = get_random_u32(); + 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. + * The interpreter uses AX in some occasions as a local temporary + * register e.g. in DIV or MOD instructions. + * + * 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_JMP32 | BPF_JEQ | BPF_K: + case BPF_JMP32 | BPF_JNE | BPF_K: + case BPF_JMP32 | BPF_JGT | BPF_K: + case BPF_JMP32 | BPF_JLT | BPF_K: + case BPF_JMP32 | BPF_JGE | BPF_K: + case BPF_JMP32 | BPF_JLE | BPF_K: + case BPF_JMP32 | BPF_JSGT | BPF_K: + case BPF_JMP32 | BPF_JSLT | BPF_K: + case BPF_JMP32 | BPF_JSGE | BPF_K: + case BPF_JMP32 | BPF_JSLE | BPF_K: + case BPF_JMP32 | BPF_JSET | BPF_K: + /* Accommodate for extra offset in case of a backjump. */ + off = from->off; + if (off < 0) + off -= 2; + *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_JMP32_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); + if (emit_zext) + *to++ = BPF_ZEXT_REG(BPF_REG_AX); + *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); + 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; + fp->stats = NULL; + fp->active = 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 (!prog->blinding_requested || 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++) { + if (bpf_pseudo_func(insn)) { + /* ld_imm64 with an address of bpf subprog is not + * a user controlled constant. Don't randomize it, + * since it will conflict with jit_subprogs() logic. + */ + insn++; + i++; + continue; + } + + /* 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, + clone->aux->verifier_zext); + if (!rewritten) + continue; + + tmp = bpf_patch_insn_single(clone, i, insn_buff, rewritten); + if (IS_ERR(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 tmp; + } + + 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, ARSH, 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, ARSH, 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), \ + /* 32-bit Jump instructions. */ \ + /* Register based. */ \ + INSN_3(JMP32, JEQ, X), \ + INSN_3(JMP32, JNE, X), \ + INSN_3(JMP32, JGT, X), \ + INSN_3(JMP32, JLT, X), \ + INSN_3(JMP32, JGE, X), \ + INSN_3(JMP32, JLE, X), \ + INSN_3(JMP32, JSGT, X), \ + INSN_3(JMP32, JSLT, X), \ + INSN_3(JMP32, JSGE, X), \ + INSN_3(JMP32, JSLE, X), \ + INSN_3(JMP32, JSET, X), \ + /* Immediate based. */ \ + INSN_3(JMP32, JEQ, K), \ + INSN_3(JMP32, JNE, K), \ + INSN_3(JMP32, JGT, K), \ + INSN_3(JMP32, JLT, K), \ + INSN_3(JMP32, JGE, K), \ + INSN_3(JMP32, JLE, K), \ + INSN_3(JMP32, JSGT, K), \ + INSN_3(JMP32, JSLT, K), \ + INSN_3(JMP32, JSGE, K), \ + INSN_3(JMP32, JSLE, K), \ + INSN_3(JMP32, JSET, K), \ + /* 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), \ + INSN_2(JMP32, 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, ATOMIC, W), \ + INSN_3(STX, ATOMIC, 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 +u64 __weak bpf_probe_read_kernel(void *dst, u32 size, const void *unsafe_ptr) +{ + memset(dst, 0, size); + return -EFAULT; +} + +/** + * ___bpf_prog_run - run eBPF program on a given context + * @regs: is the array of MAX_BPF_EXT_REG eBPF pseudo-registers + * @insn: is the array of eBPF instructions + * + * Decode and execute eBPF instructions. + * + * Return: whatever value is in %BPF_R0 at program exit + */ +static u64 ___bpf_prog_run(u64 *regs, const struct bpf_insn *insn) +{ +#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 * const jumptable[256] __annotate_jump_table = { + [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, + [BPF_LDX | BPF_PROBE_MEM | BPF_B] = &&LDX_PROBE_MEM_B, + [BPF_LDX | BPF_PROBE_MEM | BPF_H] = &&LDX_PROBE_MEM_H, + [BPF_LDX | BPF_PROBE_MEM | BPF_W] = &&LDX_PROBE_MEM_W, + [BPF_LDX | BPF_PROBE_MEM | BPF_DW] = &&LDX_PROBE_MEM_DW, + }; +#undef BPF_INSN_3_LBL +#undef BPF_INSN_2_LBL + u32 tail_call_cnt = 0; + +#define CONT ({ insn++; goto select_insn; }) +#define CONT_JMP ({ insn++; goto select_insn; }) + +select_insn: + goto *jumptable[insn->code]; + + /* Explicitly mask the register-based shift amounts with 63 or 31 + * to avoid undefined behavior. Normally this won't affect the + * generated code, for example, in case of native 64 bit archs such + * as x86-64 or arm64, the compiler is optimizing the AND away for + * the interpreter. In case of JITs, each of the JIT backends compiles + * the BPF shift operations to machine instructions which produce + * implementation-defined results in such a case; the resulting + * contents of the register may be arbitrary, but program behaviour + * as a whole remains defined. In other words, in case of JIT backends, + * the AND must /not/ be added to the emitted LSH/RSH/ARSH translation. + */ + /* ALU (shifts) */ +#define SHT(OPCODE, OP) \ + ALU64_##OPCODE##_X: \ + DST = DST OP (SRC & 63); \ + CONT; \ + ALU_##OPCODE##_X: \ + DST = (u32) DST OP ((u32) SRC & 31); \ + CONT; \ + ALU64_##OPCODE##_K: \ + DST = DST OP IMM; \ + CONT; \ + ALU_##OPCODE##_K: \ + DST = (u32) DST OP (u32) IMM; \ + CONT; + /* ALU (rest) */ +#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(XOR, ^) + ALU(MUL, *) + SHT(LSH, <<) + SHT(RSH, >>) +#undef SHT +#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; + ALU_ARSH_X: + DST = (u64) (u32) (((s32) DST) >> (SRC & 31)); + CONT; + ALU_ARSH_K: + DST = (u64) (u32) (((s32) DST) >> IMM); + CONT; + ALU64_ARSH_X: + (*(s64 *) &DST) >>= (SRC & 63); + CONT; + ALU64_ARSH_K: + (*(s64 *) &DST) >>= IMM; + CONT; + ALU64_MOD_X: + div64_u64_rem(DST, SRC, &AX); + DST = AX; + CONT; + ALU_MOD_X: + AX = (u32) DST; + DST = do_div(AX, (u32) SRC); + CONT; + ALU64_MOD_K: + div64_u64_rem(DST, IMM, &AX); + DST = AX; + CONT; + ALU_MOD_K: + AX = (u32) DST; + DST = do_div(AX, (u32) IMM); + CONT; + ALU64_DIV_X: + DST = div64_u64(DST, SRC); + CONT; + ALU_DIV_X: + AX = (u32) DST; + do_div(AX, (u32) SRC); + DST = (u32) AX; + CONT; + ALU64_DIV_K: + DST = div64_u64(DST, IMM); + CONT; + ALU_DIV_K: + AX = (u32) DST; + do_div(AX, (u32) IMM); + DST = (u32) AX; + 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 + * handled 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_JA: + insn += insn->off; + CONT; + JMP32_JA: + insn += insn->imm; + CONT; + JMP_EXIT: + return BPF_R0; + /* JMP */ +#define COND_JMP(SIGN, OPCODE, CMP_OP) \ + JMP_##OPCODE##_X: \ + if ((SIGN##64) DST CMP_OP (SIGN##64) SRC) { \ + insn += insn->off; \ + CONT_JMP; \ + } \ + CONT; \ + JMP32_##OPCODE##_X: \ + if ((SIGN##32) DST CMP_OP (SIGN##32) SRC) { \ + insn += insn->off; \ + CONT_JMP; \ + } \ + CONT; \ + JMP_##OPCODE##_K: \ + if ((SIGN##64) DST CMP_OP (SIGN##64) IMM) { \ + insn += insn->off; \ + CONT_JMP; \ + } \ + CONT; \ + JMP32_##OPCODE##_K: \ + if ((SIGN##32) DST CMP_OP (SIGN##32) IMM) { \ + insn += insn->off; \ + CONT_JMP; \ + } \ + CONT; + COND_JMP(u, JEQ, ==) + COND_JMP(u, JNE, !=) + COND_JMP(u, JGT, >) + COND_JMP(u, JLT, <) + COND_JMP(u, JGE, >=) + COND_JMP(u, JLE, <=) + COND_JMP(u, JSET, &) + COND_JMP(s, JSGT, >) + COND_JMP(s, JSLT, <) + COND_JMP(s, JSGE, >=) + COND_JMP(s, JSLE, <=) +#undef COND_JMP + /* 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. + */ + barrier_nospec(); + 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; \ + LDX_PROBE_MEM_##SIZEOP: \ + bpf_probe_read_kernel(&DST, sizeof(SIZE), \ + (const void *)(long) (SRC + insn->off)); \ + DST = *((SIZE *)&DST); \ + CONT; + + LDST(B, u8) + LDST(H, u16) + LDST(W, u32) + LDST(DW, u64) +#undef LDST + +#define ATOMIC_ALU_OP(BOP, KOP) \ + case BOP: \ + if (BPF_SIZE(insn->code) == BPF_W) \ + atomic_##KOP((u32) SRC, (atomic_t *)(unsigned long) \ + (DST + insn->off)); \ + else \ + atomic64_##KOP((u64) SRC, (atomic64_t *)(unsigned long) \ + (DST + insn->off)); \ + break; \ + case BOP | BPF_FETCH: \ + if (BPF_SIZE(insn->code) == BPF_W) \ + SRC = (u32) atomic_fetch_##KOP( \ + (u32) SRC, \ + (atomic_t *)(unsigned long) (DST + insn->off)); \ + else \ + SRC = (u64) atomic64_fetch_##KOP( \ + (u64) SRC, \ + (atomic64_t *)(unsigned long) (DST + insn->off)); \ + break; + + STX_ATOMIC_DW: + STX_ATOMIC_W: + switch (IMM) { + ATOMIC_ALU_OP(BPF_ADD, add) + ATOMIC_ALU_OP(BPF_AND, and) + ATOMIC_ALU_OP(BPF_OR, or) + ATOMIC_ALU_OP(BPF_XOR, xor) +#undef ATOMIC_ALU_OP + + case BPF_XCHG: + if (BPF_SIZE(insn->code) == BPF_W) + SRC = (u32) atomic_xchg( + (atomic_t *)(unsigned long) (DST + insn->off), + (u32) SRC); + else + SRC = (u64) atomic64_xchg( + (atomic64_t *)(unsigned long) (DST + insn->off), + (u64) SRC); + break; + case BPF_CMPXCHG: + if (BPF_SIZE(insn->code) == BPF_W) + BPF_R0 = (u32) atomic_cmpxchg( + (atomic_t *)(unsigned long) (DST + insn->off), + (u32) BPF_R0, (u32) SRC); + else + BPF_R0 = (u64) atomic64_cmpxchg( + (atomic64_t *)(unsigned long) (DST + insn->off), + (u64) BPF_R0, (u64) SRC); + break; + + default: + goto default_label; + } + 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 (imm: 0x%x)\n", + insn->code, insn->imm); + BUG_ON(1); + return 0; +} + +#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); \ +} + +#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); \ +} + +#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_map_compatible(struct bpf_map *map, + const struct bpf_prog *fp) +{ + enum bpf_prog_type prog_type = resolve_prog_type(fp); + bool ret; + + if (fp->kprobe_override) + return false; + + spin_lock(&map->owner.lock); + if (!map->owner.type) { + /* There's no owner yet where we could check for + * compatibility. + */ + map->owner.type = prog_type; + map->owner.jited = fp->jited; + map->owner.xdp_has_frags = fp->aux->xdp_has_frags; + ret = true; + } else { + ret = map->owner.type == prog_type && + map->owner.jited == fp->jited && + map->owner.xdp_has_frags == fp->aux->xdp_has_frags; + } + spin_unlock(&map->owner.lock); + + return ret; +} + +static int bpf_check_tail_call(const struct bpf_prog *fp) +{ + struct bpf_prog_aux *aux = fp->aux; + int i, ret = 0; + + mutex_lock(&aux->used_maps_mutex); + for (i = 0; i < aux->used_map_cnt; i++) { + struct bpf_map *map = aux->used_maps[i]; + + if (!map_type_contains_progs(map)) + continue; + + if (!bpf_prog_map_compatible(map, fp)) { + ret = -EINVAL; + goto out; + } + } + +out: + mutex_unlock(&aux->used_maps_mutex); + return ret; +} + +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 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() function. + * + * Return: the &fp argument along with &err set to 0 for success or + * a negative errno code on failure + */ +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. + */ + bool jit_needed = false; + + if (fp->bpf_func) + goto finalize; + + if (IS_ENABLED(CONFIG_BPF_JIT_ALWAYS_ON) || + bpf_prog_has_kfunc_call(fp)) + jit_needed = true; + + 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)) { + *err = bpf_prog_alloc_jited_linfo(fp); + if (*err) + return fp; + + fp = bpf_int_jit_compile(fp); + bpf_prog_jit_attempt_done(fp); + if (!fp->jited && jit_needed) { + *err = -ENOTSUPP; + return fp; + } + } 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, + }, +}; + +struct bpf_empty_prog_array bpf_empty_prog_array = { + .null_prog = NULL, +}; +EXPORT_SYMBOL(bpf_empty_prog_array); + +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 &bpf_empty_prog_array.hdr; +} + +void bpf_prog_array_free(struct bpf_prog_array *progs) +{ + if (!progs || progs == &bpf_empty_prog_array.hdr) + return; + kfree_rcu(progs, rcu); +} + +static void __bpf_prog_array_free_sleepable_cb(struct rcu_head *rcu) +{ + struct bpf_prog_array *progs; + + progs = container_of(rcu, struct bpf_prog_array, rcu); + kfree_rcu(progs, rcu); +} + +void bpf_prog_array_free_sleepable(struct bpf_prog_array *progs) +{ + if (!progs || progs == &bpf_empty_prog_array.hdr) + return; + call_rcu_tasks_trace(&progs->rcu, __bpf_prog_array_free_sleepable_cb); +} + +int bpf_prog_array_length(struct bpf_prog_array *array) +{ + struct bpf_prog_array_item *item; + u32 cnt = 0; + + for (item = array->items; item->prog; item++) + if (item->prog != &dummy_bpf_prog.prog) + cnt++; + return cnt; +} + +bool bpf_prog_array_is_empty(struct bpf_prog_array *array) +{ + struct bpf_prog_array_item *item; + + for (item = array->items; item->prog; item++) + if (item->prog != &dummy_bpf_prog.prog) + return false; + return true; +} + +static bool bpf_prog_array_copy_core(struct bpf_prog_array *array, + u32 *prog_ids, + u32 request_cnt) +{ + struct bpf_prog_array_item *item; + int i = 0; + + for (item = array->items; 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 *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. + */ + ids = kcalloc(cnt, sizeof(u32), GFP_USER | __GFP_NOWARN); + if (!ids) + return -ENOMEM; + nospc = bpf_prog_array_copy_core(array, ids, cnt); + 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 *array, + struct bpf_prog *old_prog) +{ + struct bpf_prog_array_item *item; + + for (item = array->items; item->prog; item++) + if (item->prog == old_prog) { + WRITE_ONCE(item->prog, &dummy_bpf_prog.prog); + break; + } +} + +/** + * bpf_prog_array_delete_safe_at() - Replaces the program at the given + * index into the program array with + * a dummy no-op program. + * @array: a bpf_prog_array + * @index: the index of the program to replace + * + * Skips over dummy programs, by not counting them, when calculating + * the position of the program to replace. + * + * Return: + * * 0 - Success + * * -EINVAL - Invalid index value. Must be a non-negative integer. + * * -ENOENT - Index out of range + */ +int bpf_prog_array_delete_safe_at(struct bpf_prog_array *array, int index) +{ + return bpf_prog_array_update_at(array, index, &dummy_bpf_prog.prog); +} + +/** + * bpf_prog_array_update_at() - Updates the program at the given index + * into the program array. + * @array: a bpf_prog_array + * @index: the index of the program to update + * @prog: the program to insert into the array + * + * Skips over dummy programs, by not counting them, when calculating + * the position of the program to update. + * + * Return: + * * 0 - Success + * * -EINVAL - Invalid index value. Must be a non-negative integer. + * * -ENOENT - Index out of range + */ +int bpf_prog_array_update_at(struct bpf_prog_array *array, int index, + struct bpf_prog *prog) +{ + struct bpf_prog_array_item *item; + + if (unlikely(index < 0)) + return -EINVAL; + + for (item = array->items; item->prog; item++) { + if (item->prog == &dummy_bpf_prog.prog) + continue; + if (!index) { + WRITE_ONCE(item->prog, prog); + return 0; + } + index--; + } + return -ENOENT; +} + +int bpf_prog_array_copy(struct bpf_prog_array *old_array, + struct bpf_prog *exclude_prog, + struct bpf_prog *include_prog, + u64 bpf_cookie, + struct bpf_prog_array **new_array) +{ + int new_prog_cnt, carry_prog_cnt = 0; + struct bpf_prog_array_item *existing, *new; + struct bpf_prog_array *array; + bool found_exclude = false; + + /* 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; + new = array->items; + + /* 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) + continue; + + new->prog = existing->prog; + new->bpf_cookie = existing->bpf_cookie; + new++; + } + } + if (include_prog) { + new->prog = include_prog; + new->bpf_cookie = bpf_cookie; + new++; + } + new->prog = NULL; + *new_array = array; + return 0; +} + +int bpf_prog_array_copy_info(struct bpf_prog_array *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; +} + +void __bpf_free_used_maps(struct bpf_prog_aux *aux, + struct bpf_map **used_maps, u32 len) +{ + struct bpf_map *map; + u32 i; + + for (i = 0; i < len; i++) { + map = used_maps[i]; + if (map->ops->map_poke_untrack) + map->ops->map_poke_untrack(map, aux); + bpf_map_put(map); + } +} + +static void bpf_free_used_maps(struct bpf_prog_aux *aux) +{ + __bpf_free_used_maps(aux, aux->used_maps, aux->used_map_cnt); + kfree(aux->used_maps); +} + +void __bpf_free_used_btfs(struct bpf_prog_aux *aux, + struct btf_mod_pair *used_btfs, u32 len) +{ +#ifdef CONFIG_BPF_SYSCALL + struct btf_mod_pair *btf_mod; + u32 i; + + for (i = 0; i < len; i++) { + btf_mod = &used_btfs[i]; + if (btf_mod->module) + module_put(btf_mod->module); + btf_put(btf_mod->btf); + } +#endif +} + +static void bpf_free_used_btfs(struct bpf_prog_aux *aux) +{ + __bpf_free_used_btfs(aux, aux->used_btfs, aux->used_btf_cnt); + kfree(aux->used_btfs); +} + +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); +#ifdef CONFIG_BPF_SYSCALL + bpf_free_kfunc_btf_tab(aux->kfunc_btf_tab); +#endif +#ifdef CONFIG_CGROUP_BPF + if (aux->cgroup_atype != CGROUP_BPF_ATTACH_TYPE_INVALID) + bpf_cgroup_atype_put(aux->cgroup_atype); +#endif + bpf_free_used_maps(aux); + bpf_free_used_btfs(aux); + 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 + if (aux->dst_trampoline) + bpf_trampoline_put(aux->dst_trampoline); + for (i = 0; i < aux->func_cnt; i++) { + /* We can just unlink the subprog poke descriptor table as + * it was originally linked to the main program and is also + * released along with it. + */ + aux->func[i]->aux->poke_tab = NULL; + 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); + } +} + +void bpf_prog_free(struct bpf_prog *fp) +{ + struct bpf_prog_aux *aux = fp->aux; + + if (aux->dst_prog) + bpf_prog_put(aux->dst_prog); + 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; +} + +BPF_CALL_0(bpf_get_raw_cpu_id) +{ + return raw_smp_processor_id(); +} + +/* 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_map_push_elem_proto __weak; +const struct bpf_func_proto bpf_map_pop_elem_proto __weak; +const struct bpf_func_proto bpf_map_peek_elem_proto __weak; +const struct bpf_func_proto bpf_map_lookup_percpu_elem_proto __weak; +const struct bpf_func_proto bpf_spin_lock_proto __weak; +const struct bpf_func_proto bpf_spin_unlock_proto __weak; +const struct bpf_func_proto bpf_jiffies64_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_ktime_get_boot_ns_proto __weak; +const struct bpf_func_proto bpf_ktime_get_coarse_ns_proto __weak; +const struct bpf_func_proto bpf_ktime_get_tai_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_get_current_cgroup_id_proto __weak; +const struct bpf_func_proto bpf_get_current_ancestor_cgroup_id_proto __weak; +const struct bpf_func_proto bpf_get_local_storage_proto __weak; +const struct bpf_func_proto bpf_get_ns_current_pid_tgid_proto __weak; +const struct bpf_func_proto bpf_snprintf_btf_proto __weak; +const struct bpf_func_proto bpf_seq_printf_btf_proto __weak; +const struct bpf_func_proto bpf_set_retval_proto __weak; +const struct bpf_func_proto bpf_get_retval_proto __weak; + +const struct bpf_func_proto * __weak bpf_get_trace_printk_proto(void) +{ + return NULL; +} + +const struct bpf_func_proto * __weak bpf_get_trace_vprintk_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; +} + +/* Return TRUE if the JIT backend wants verifier to enable sub-register usage + * analysis code and wants explicit zero extension inserted by verifier. + * Otherwise, return FALSE. + * + * The verifier inserts an explicit zero extension after BPF_CMPXCHGs even if + * you don't override this. JITs that don't want these extra insns can detect + * them using insn_is_zext. + */ +bool __weak bpf_jit_needs_zext(void) +{ + return false; +} + +/* Return TRUE if the JIT backend supports mixing bpf2bpf and tailcalls. */ +bool __weak bpf_jit_supports_subprog_tailcalls(void) +{ + return false; +} + +bool __weak bpf_jit_supports_kfunc_call(void) +{ + 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; +} + +int __weak bpf_arch_text_poke(void *ip, enum bpf_text_poke_type t, + void *addr1, void *addr2) +{ + return -ENOTSUPP; +} + +void * __weak bpf_arch_text_copy(void *dst, void *src, size_t len) +{ + return ERR_PTR(-ENOTSUPP); +} + +int __weak bpf_arch_text_invalidate(void *dst, size_t len) +{ + return -ENOTSUPP; +} + +DEFINE_STATIC_KEY_FALSE(bpf_stats_enabled_key); +EXPORT_SYMBOL(bpf_stats_enabled_key); + +/* All definitions of tracepoints related to BPF. */ +#define CREATE_TRACE_POINTS +#include <linux/bpf_trace.h> + +EXPORT_TRACEPOINT_SYMBOL_GPL(xdp_exception); +EXPORT_TRACEPOINT_SYMBOL_GPL(xdp_bulk_tx); |