[PATCH bpf-next] bpf: Enforce 'return 0' in BTF-enabled raw_tp programs
From: Alexei Starovoitov <ast@kernel.org>
Date: 2019-10-29 03:24:32
Also in:
bpf
Subsystem:
bpf [core], bpf [general] (safe dynamic programs and tools), the rest · Maintainers:
Alexei Starovoitov, Daniel Borkmann, Andrii Nakryiko, Eduard Zingerman, Kumar Kartikeya Dwivedi, Linus Torvalds
The return value of raw_tp programs is ignored by __bpf_trace_run() that calls them. The verifier also allows any value to be returned. For BTF-enabled raw_tp lets enforce 'return 0', so that return value can be used for something in the future. Signed-off-by: Alexei Starovoitov <ast@kernel.org> --- kernel/bpf/verifier.c | 5 +++++ 1 file changed, 5 insertions(+)
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index c59778c0fc4d..6b0de04f8b91 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c@@ -6279,6 +6279,11 @@ static int check_return_code(struct bpf_verifier_env *env) case BPF_PROG_TYPE_CGROUP_SYSCTL: case BPF_PROG_TYPE_CGROUP_SOCKOPT: break; + case BPF_PROG_TYPE_RAW_TRACEPOINT: + if (!env->prog->aux->attach_btf_id) + return 0; + range = tnum_const(0); + break; default: return 0; }
--
2.17.1