[PATCHv8 bpf-next 01/13] bpf: Allow return values 0 and 1 for kprobe session

[Jiri Olsa]

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

Fixes: 535a3692ba72 ("bpf: Add support for kprobe session attach")
Acked-by: Andrii Nakryiko <and...@kernel.org>
Signed-off-by: Jiri Olsa <jo...@kernel.org>
---
 kernel/bpf/verifier.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index f514247ba8ba..5c941fd1b141 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -15915,6 +15915,15 @@ 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:
+                       range = retval_range(0, 1);
+                       break;
+               default:
+                       return 0;
+               }
+               break;
        case BPF_PROG_TYPE_SK_LOOKUP:
                range = retval_range(SK_DROP, SK_PASS);
                break;
-- 
2.46.2