diff options
| author | Alexei Starovoitov <ast@kernel.org> | 2019-11-14 10:57:14 -0800 |
|---|---|---|
| committer | Daniel Borkmann <daniel@iogearbox.net> | 2019-11-15 23:44:20 +0100 |
| commit | 9cc31b3a092d9bf2a18f09ad77e727ddb42a5b1e (patch) | |
| tree | 36be1bd2c248be20e0688560b3b678357807444e /kernel/bpf/verifier.c | |
| parent | 9fd4a39dc7fe734d26eb89ea97e8c91331c6378c (diff) | |
bpf: Fix race in btf_resolve_helper_id()
btf_resolve_helper_id() caching logic is a bit racy, since under root the
verifier can verify several programs in parallel. Fix it with READ/WRITE_ONCE.
Fix the type as well, since error is also recorded.
Fixes: a7658e1a4164 ("bpf: Check types of arguments passed into helpers")
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Song Liu <songliubraving@fb.com>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/20191114185720.1641606-15-ast@kernel.org
Diffstat (limited to 'kernel/bpf/verifier.c')
| -rw-r--r-- | kernel/bpf/verifier.c | 8 |
1 files changed, 3 insertions, 5 deletions
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 8f89cfa93e88..e78ec7990767 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -4147,11 +4147,9 @@ static int check_helper_call(struct bpf_verifier_env *env, int func_id, int insn meta.func_id = func_id; /* check args */ for (i = 0; i < 5; i++) { - if (fn->arg_type[i] == ARG_PTR_TO_BTF_ID) { - if (!fn->btf_id[i]) - fn->btf_id[i] = btf_resolve_helper_id(&env->log, fn->func, i); - meta.btf_id = fn->btf_id[i]; - } + err = btf_resolve_helper_id(&env->log, fn, i); + if (err > 0) + meta.btf_id = err; err = check_func_arg(env, BPF_REG_1 + i, fn->arg_type[i], &meta); if (err) return err; |