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| author | Yonghong Song <yhs@fb.com> | 2019-05-25 11:57:53 -0700 |
|---|---|---|
| committer | Daniel Borkmann <daniel@iogearbox.net> | 2019-05-28 10:51:33 +0200 |
| commit | e1afb70252a8614e1ef7aec05ff1b84fd324b782 (patch) | |
| tree | f8c6ffc8af4675f6e90878073ca03f59072ac420 /kernel/trace/bpf_trace.c | |
| parent | 0d97dacc46d9af2daba1af224747d452bd988365 (diff) | |
| download | lwn-e1afb70252a8614e1ef7aec05ff1b84fd324b782.tar.gz lwn-e1afb70252a8614e1ef7aec05ff1b84fd324b782.zip | |
bpf: check signal validity in nmi for bpf_send_signal() helper
Commit 8b401f9ed244 ("bpf: implement bpf_send_signal() helper")
introduced bpf_send_signal() helper. If the context is nmi,
the sending signal work needs to be deferred to irq_work.
If the signal is invalid, the error will appear in irq_work
and it won't be propagated to user.
This patch did an early check in the helper itself to notify
user invalid signal, as suggested by Daniel.
Suggested-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Diffstat (limited to 'kernel/trace/bpf_trace.c')
| -rw-r--r-- | kernel/trace/bpf_trace.c | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c index 70029eafc71f..fe73926a07cd 100644 --- a/kernel/trace/bpf_trace.c +++ b/kernel/trace/bpf_trace.c @@ -600,6 +600,12 @@ BPF_CALL_1(bpf_send_signal, u32, sig) return -EPERM; if (in_nmi()) { + /* Do an early check on signal validity. Otherwise, + * the error is lost in deferred irq_work. + */ + if (unlikely(!valid_signal(sig))) + return -EINVAL; + work = this_cpu_ptr(&send_signal_work); if (work->irq_work.flags & IRQ_WORK_BUSY) return -EBUSY; |