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bpf: Force kprobe multi expected_attach_type for kprobe_multi link

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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
This commit is contained in:
Jiri Olsa 2023-06-18 15:14:14 +02:00 committed by Daniel Borkmann
parent 9724160b39
commit db8eae6bc5
1 changed files with 5 additions and 0 deletions
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5
kernel/bpf/syscall.c
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@ -3440,6 +3440,11 @@ static int bpf_prog_attach_check_attach_type(const struct bpf_prog *prog,
return prog->enforce_expected_attach_type && return prog->enforce_expected_attach_type &&
prog->expected_attach_type != attach_type ? prog->expected_attach_type != attach_type ?
-EINVAL : 0; -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: default:
return 0; return 0;
} }