From: Jiri Olsa jolsa@kernel.org
[ Upstream commit db8eae6bc5c702d8e3ab2d0c6bb5976c131576eb ]
We currently allow to create perf link for program with expected_attach_type == BPF_TRACE_KPROBE_MULTI.
This will cause crash when we call helpers like get_attach_cookie or get_func_ip in such program, because it will call the kprobe_multi's version (current->bpf_ctx context setup) of those helpers while it expects perf_link's current->bpf_ctx context setup.
Making sure that we use BPF_TRACE_KPROBE_MULTI expected_attach_type only for programs attaching through kprobe_multi link.
Fixes: ca74823c6e16 ("bpf: Add cookie support to programs attached with kprobe multi link") Signed-off-by: Jiri Olsa jolsa@kernel.org Signed-off-by: Andrii Nakryiko andrii@kernel.org Signed-off-by: Daniel Borkmann daniel@iogearbox.net Link: https://lore.kernel.org/bpf/20230618131414.75649-1-jolsa@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- kernel/bpf/syscall.c | 5 +++++ 1 file changed, 5 insertions(+)
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index 6c61dba26f4d9..8633ec4f92df3 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -3383,6 +3383,11 @@ static int bpf_prog_attach_check_attach_type(const struct bpf_prog *prog, return prog->enforce_expected_attach_type && prog->expected_attach_type != attach_type ? -EINVAL : 0; + case BPF_PROG_TYPE_KPROBE: + if (prog->expected_attach_type == BPF_TRACE_KPROBE_MULTI && + attach_type != BPF_TRACE_KPROBE_MULTI) + return -EINVAL; + return 0; default: return 0; }