diff options
Diffstat (limited to 'kernel/bpf/verifier.c')
| -rw-r--r-- | kernel/bpf/verifier.c | 57 |
1 files changed, 43 insertions, 14 deletions
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 67a13110bc22..cf580e4c00f5 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -2530,6 +2530,16 @@ static int check_reg_arg(struct bpf_verifier_env *env, u32 regno, return 0; } +static void mark_jmp_point(struct bpf_verifier_env *env, int idx) +{ + env->insn_aux_data[idx].jmp_point = true; +} + +static bool is_jmp_point(struct bpf_verifier_env *env, int insn_idx) +{ + return env->insn_aux_data[insn_idx].jmp_point; +} + /* for any branch, call, exit record the history of jmps in the given state */ static int push_jmp_history(struct bpf_verifier_env *env, struct bpf_verifier_state *cur) @@ -2538,6 +2548,9 @@ static int push_jmp_history(struct bpf_verifier_env *env, struct bpf_idx_pair *p; size_t alloc_size; + if (!is_jmp_point(env, env->insn_idx)) + return 0; + cnt++; alloc_size = kmalloc_size_roundup(size_mul(cnt, sizeof(*p))); p = krealloc(cur->jmp_history, alloc_size, GFP_USER); @@ -12140,11 +12153,16 @@ static struct bpf_verifier_state_list **explored_state( return &env->explored_states[(idx ^ state->callsite) % state_htab_size(env)]; } -static void init_explored_state(struct bpf_verifier_env *env, int idx) +static void mark_prune_point(struct bpf_verifier_env *env, int idx) { env->insn_aux_data[idx].prune_point = true; } +static bool is_prune_point(struct bpf_verifier_env *env, int insn_idx) +{ + return env->insn_aux_data[insn_idx].prune_point; +} + enum { DONE_EXPLORING = 0, KEEP_EXPLORING = 1, @@ -12173,9 +12191,11 @@ static int push_insn(int t, int w, int e, struct bpf_verifier_env *env, return -EINVAL; } - if (e == BRANCH) + if (e == BRANCH) { /* mark branch target for state pruning */ - init_explored_state(env, w); + mark_prune_point(env, w); + mark_jmp_point(env, w); + } if (insn_state[w] == 0) { /* tree-edge */ @@ -12213,10 +12233,13 @@ static int visit_func_call_insn(int t, int insn_cnt, if (ret) return ret; - if (t + 1 < insn_cnt) - init_explored_state(env, t + 1); + if (t + 1 < insn_cnt) { + mark_prune_point(env, t + 1); + mark_jmp_point(env, t + 1); + } if (visit_callee) { - init_explored_state(env, t); + mark_prune_point(env, t); + mark_jmp_point(env, t); ret = push_insn(t, t + insns[t].imm + 1, BRANCH, env, /* It's ok to allow recursion from CFG point of * view. __check_func_call() will do the actual @@ -12250,13 +12273,15 @@ static int visit_insn(int t, int insn_cnt, struct bpf_verifier_env *env) return DONE_EXPLORING; case BPF_CALL: - if (insns[t].imm == BPF_FUNC_timer_set_callback) + if (insns[t].imm == BPF_FUNC_timer_set_callback) { /* Mark this call insn to trigger is_state_visited() check * before call itself is processed by __check_func_call(). * Otherwise new async state will be pushed for further * exploration. */ - init_explored_state(env, t); + mark_prune_point(env, t); + mark_jmp_point(env, t); + } return visit_func_call_insn(t, insn_cnt, insns, env, insns[t].src_reg == BPF_PSEUDO_CALL); @@ -12274,18 +12299,22 @@ static int visit_insn(int t, int insn_cnt, struct bpf_verifier_env *env) * but it's marked, since backtracking needs * to record jmp history in is_state_visited(). */ - init_explored_state(env, t + insns[t].off + 1); + mark_prune_point(env, t + insns[t].off + 1); + mark_jmp_point(env, t + insns[t].off + 1); /* tell verifier to check for equivalent states * after every call and jump */ - if (t + 1 < insn_cnt) - init_explored_state(env, t + 1); + if (t + 1 < insn_cnt) { + mark_prune_point(env, t + 1); + mark_jmp_point(env, t + 1); + } return ret; default: /* conditional jump with two edges */ - init_explored_state(env, t); + mark_prune_point(env, t); + mark_jmp_point(env, t); ret = push_insn(t, t + 1, FALLTHROUGH, env, true); if (ret) return ret; @@ -13320,11 +13349,11 @@ static int is_state_visited(struct bpf_verifier_env *env, int insn_idx) bool add_new_state = env->test_state_freq ? true : false; cur->last_insn_idx = env->prev_insn_idx; - if (!env->insn_aux_data[insn_idx].prune_point) + if (!is_prune_point(env, insn_idx)) /* this 'insn_idx' instruction wasn't marked, so we will not * be doing state search here */ - return 0; + return push_jmp_history(env, cur); /* bpf progs typically have pruning point every 4 instructions * http://vger.kernel.org/bpfconf2019.html#session-1 |