diff options
| author | Yonghong Song <yhs@fb.com> | 2021-02-26 12:49:20 -0800 |
|---|---|---|
| committer | Alexei Starovoitov <ast@kernel.org> | 2021-02-26 13:23:52 -0800 |
| commit | efdb22de7dcd3b24b8154b3c3ba496f62afea00c (patch) | |
| tree | 37efc018f6e6244e1afd33de75cdb0c8bc09c562 /kernel | |
| parent | 86fd166575c38c17ecd3a6b8fb9c64fa19871486 (diff) | |
bpf: Factor out visit_func_call_insn() in check_cfg()
During verifier check_cfg(), all instructions are
visited to ensure verifier can handle program control flows.
This patch factored out function visit_func_call_insn()
so it can be reused in later patch to visit callback function
calls. There is no functionality change for this patch.
Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20210226204920.3884136-1-yhs@fb.com
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/bpf/verifier.c | 35 |
1 files changed, 23 insertions, 12 deletions
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 9336bac39027..b14fab7a7a16 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -8592,6 +8592,27 @@ static int push_insn(int t, int w, int e, struct bpf_verifier_env *env, return DONE_EXPLORING; } +static int visit_func_call_insn(int t, int insn_cnt, + struct bpf_insn *insns, + struct bpf_verifier_env *env, + bool visit_callee) +{ + int ret; + + ret = push_insn(t, t + 1, FALLTHROUGH, env, false); + if (ret) + return ret; + + if (t + 1 < insn_cnt) + init_explored_state(env, t + 1); + if (visit_callee) { + init_explored_state(env, t); + ret = push_insn(t, t + insns[t].imm + 1, BRANCH, + env, false); + } + return ret; +} + /* Visits the instruction at index t and returns one of the following: * < 0 - an error occurred * DONE_EXPLORING - the instruction was fully explored @@ -8612,18 +8633,8 @@ static int visit_insn(int t, int insn_cnt, struct bpf_verifier_env *env) return DONE_EXPLORING; case BPF_CALL: - ret = push_insn(t, t + 1, FALLTHROUGH, env, false); - if (ret) - return ret; - - if (t + 1 < insn_cnt) - init_explored_state(env, t + 1); - if (insns[t].src_reg == BPF_PSEUDO_CALL) { - init_explored_state(env, t); - ret = push_insn(t, t + insns[t].imm + 1, BRANCH, - env, false); - } - return ret; + return visit_func_call_insn(t, insn_cnt, insns, env, + insns[t].src_reg == BPF_PSEUDO_CALL); case BPF_JA: if (BPF_SRC(insns[t].code) != BPF_K) |