diff options
| -rw-r--r-- | include/linux/bpf_verifier.h | 11 | ||||
| -rw-r--r-- | kernel/bpf/verifier.c | 68 |
2 files changed, 79 insertions, 0 deletions
diff --git a/include/linux/bpf_verifier.h b/include/linux/bpf_verifier.h index 9457a22fc6e0..c5cb661712c9 100644 --- a/include/linux/bpf_verifier.h +++ b/include/linux/bpf_verifier.h @@ -59,6 +59,12 @@ struct bpf_insn_aux_data { #define MAX_USED_MAPS 64 /* max number of maps accessed by one eBPF program */ +struct bpf_verifier_env; +struct bpf_ext_analyzer_ops { + int (*insn_hook)(struct bpf_verifier_env *env, + int insn_idx, int prev_insn_idx); +}; + /* single container for all structs * one verifier_env per bpf_check() call */ @@ -68,6 +74,8 @@ struct bpf_verifier_env { int stack_size; /* number of states to be processed */ struct bpf_verifier_state cur_state; /* current verifier state */ struct bpf_verifier_state_list **explored_states; /* search pruning optimization */ + const struct bpf_ext_analyzer_ops *analyzer_ops; /* external analyzer ops */ + void *analyzer_priv; /* pointer to external analyzer's private data */ struct bpf_map *used_maps[MAX_USED_MAPS]; /* array of map's used by eBPF program */ u32 used_map_cnt; /* number of used maps */ u32 id_gen; /* used to generate unique reg IDs */ @@ -76,4 +84,7 @@ struct bpf_verifier_env { struct bpf_insn_aux_data *insn_aux_data; /* array of per-insn state */ }; +int bpf_analyzer(struct bpf_prog *prog, const struct bpf_ext_analyzer_ops *ops, + void *priv); + #endif /* _LINUX_BPF_VERIFIER_H */ diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index dca2b9b1d02e..ee86a77dc40b 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -632,6 +632,10 @@ static int check_packet_access(struct bpf_verifier_env *env, u32 regno, int off, static int check_ctx_access(struct bpf_verifier_env *env, int off, int size, enum bpf_access_type t, enum bpf_reg_type *reg_type) { + /* for analyzer ctx accesses are already validated and converted */ + if (env->analyzer_ops) + return 0; + if (env->prog->aux->ops->is_valid_access && env->prog->aux->ops->is_valid_access(off, size, t, reg_type)) { /* remember the offset of last byte accessed in ctx */ @@ -2225,6 +2229,15 @@ static int is_state_visited(struct bpf_verifier_env *env, int insn_idx) return 0; } +static int ext_analyzer_insn_hook(struct bpf_verifier_env *env, + int insn_idx, int prev_insn_idx) +{ + if (!env->analyzer_ops || !env->analyzer_ops->insn_hook) + return 0; + + return env->analyzer_ops->insn_hook(env, insn_idx, prev_insn_idx); +} + static int do_check(struct bpf_verifier_env *env) { struct bpf_verifier_state *state = &env->cur_state; @@ -2283,6 +2296,10 @@ static int do_check(struct bpf_verifier_env *env) print_bpf_insn(insn); } + err = ext_analyzer_insn_hook(env, insn_idx, prev_insn_idx); + if (err) + return err; + if (class == BPF_ALU || class == BPF_ALU64) { err = check_alu_op(env, insn); if (err) @@ -2845,3 +2862,54 @@ err_free_env: kfree(env); return ret; } + +int bpf_analyzer(struct bpf_prog *prog, const struct bpf_ext_analyzer_ops *ops, + void *priv) +{ + struct bpf_verifier_env *env; + int ret; + + env = kzalloc(sizeof(struct bpf_verifier_env), GFP_KERNEL); + if (!env) + return -ENOMEM; + + env->insn_aux_data = vzalloc(sizeof(struct bpf_insn_aux_data) * + prog->len); + ret = -ENOMEM; + if (!env->insn_aux_data) + goto err_free_env; + env->prog = prog; + env->analyzer_ops = ops; + env->analyzer_priv = priv; + + /* grab the mutex to protect few globals used by verifier */ + mutex_lock(&bpf_verifier_lock); + + log_level = 0; + + env->explored_states = kcalloc(env->prog->len, + sizeof(struct bpf_verifier_state_list *), + GFP_KERNEL); + ret = -ENOMEM; + if (!env->explored_states) + goto skip_full_check; + + ret = check_cfg(env); + if (ret < 0) + goto skip_full_check; + + env->allow_ptr_leaks = capable(CAP_SYS_ADMIN); + + ret = do_check(env); + +skip_full_check: + while (pop_stack(env, NULL) >= 0); + free_states(env); + + mutex_unlock(&bpf_verifier_lock); + vfree(env->insn_aux_data); +err_free_env: + kfree(env); + return ret; +} +EXPORT_SYMBOL_GPL(bpf_analyzer); |