diff options
| -rw-r--r-- | kernel/bpf/verifier.c | 34 |
1 files changed, 14 insertions, 20 deletions
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 5b293b4abb70..37e0affa515e 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -769,7 +769,7 @@ static int add_subprog(struct bpf_verifier_env *env, int off) ret = find_subprog(env, off); if (ret >= 0) return 0; - if (env->subprog_cnt > BPF_MAX_SUBPROGS) { + if (env->subprog_cnt >= BPF_MAX_SUBPROGS) { verbose(env, "too many subprograms\n"); return -E2BIG; } @@ -810,16 +810,18 @@ static int check_subprogs(struct bpf_verifier_env *env) return ret; } + /* Add a fake 'exit' subprog which could simplify subprog iteration + * logic. 'subprog_cnt' should not be increased. + */ + subprog[env->subprog_cnt].start = insn_cnt; + if (env->log.level > 1) for (i = 0; i < env->subprog_cnt; i++) verbose(env, "func#%d @%d\n", i, subprog[i].start); /* now check that all jumps are within the same subprog */ - subprog_start = 0; - if (env->subprog_cnt == cur_subprog + 1) - subprog_end = insn_cnt; - else - subprog_end = subprog[cur_subprog + 1].start; + subprog_start = subprog[cur_subprog].start; + subprog_end = subprog[cur_subprog + 1].start; for (i = 0; i < insn_cnt; i++) { u8 code = insn[i].code; @@ -843,11 +845,9 @@ next: verbose(env, "last insn is not an exit or jmp\n"); return -EINVAL; } - cur_subprog++; subprog_start = subprog_end; - if (env->subprog_cnt == cur_subprog + 1) - subprog_end = insn_cnt; - else + cur_subprog++; + if (cur_subprog < env->subprog_cnt) subprog_end = subprog[cur_subprog + 1].start; } } @@ -1502,7 +1502,6 @@ static int check_max_stack_depth(struct bpf_verifier_env *env) int depth = 0, frame = 0, idx = 0, i = 0, subprog_end; struct bpf_subprog_info *subprog = env->subprog_info; struct bpf_insn *insn = env->prog->insnsi; - int insn_cnt = env->prog->len; int ret_insn[MAX_CALL_FRAMES]; int ret_prog[MAX_CALL_FRAMES]; @@ -1517,10 +1516,7 @@ process_func: return -EACCES; } continue_func: - if (env->subprog_cnt == idx + 1) - subprog_end = insn_cnt; - else - subprog_end = subprog[idx + 1].start; + subprog_end = subprog[idx + 1].start; for (; i < subprog_end; i++) { if (insn[i].code != (BPF_JMP | BPF_CALL)) continue; @@ -5141,7 +5137,8 @@ static void adjust_subprog_starts(struct bpf_verifier_env *env, u32 off, u32 len if (len == 1) return; - for (i = 0; i < env->subprog_cnt; i++) { + /* NOTE: fake 'exit' subprog should be updated as well. */ + for (i = 0; i <= env->subprog_cnt; i++) { if (env->subprog_info[i].start < off) continue; env->subprog_info[i].start += len - 1; @@ -5339,10 +5336,7 @@ static int jit_subprogs(struct bpf_verifier_env *env) for (i = 0; i < env->subprog_cnt; i++) { subprog_start = subprog_end; - if (env->subprog_cnt == i + 1) - subprog_end = prog->len; - else - subprog_end = env->subprog_info[i + 1].start; + subprog_end = env->subprog_info[i + 1].start; len = subprog_end - subprog_start; func[i] = bpf_prog_alloc(bpf_prog_size(len), GFP_USER); |