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

[Jiri Olsa <jolsa@kernel.org>]

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