[PATCHv4 05/14] bpf: Allow return values 0 and 1 for uprobe/kprobe session

Jiri Olsa
2024-09-17T08:51:35Z

The uprobe and kprobe session program can return only 0 or 1,
instruct verifier to check for that.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
---
kernel/bpf/verifier.c | 10 ++++++++++
1 file changed, 10 insertions(+)

diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index d8520095ca03..988858fc37e5 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -15668,6 +15668,16 @@ static int check_return_code(struct bpf_verifier_env *env, int regno, const char
return -ENOTSUPP;
}
break;
+ case BPF_PROG_TYPE_KPROBE:
+ switch (env->prog->expected_attach_type) {
+ case BPF_TRACE_KPROBE_SESSION:
+ case BPF_TRACE_UPROBE_SESSION:
+ range = retval_range(0, 1);
+ break;
+ default:
+ return 0;
+ }
+ break;
case BPF_PROG_TYPE_SK_LOOKUP:
range = retval_range(SK_DROP, SK_PASS);
break;
--
2.46.0