diff options
| author | Takashi Iwai <tiwai@suse.de> | 2016-02-01 14:06:42 +0300 |
|---|---|---|
| committer | Willy Tarreau <w@1wt.eu> | 2016-03-12 16:25:45 +0300 |
| commit | 92b51a4da1c46bdd9897dda12ca569856c0a93d7 (patch) | |
| tree | d202e3a4c92dd838fca99fa37a4bda7da4906670 | |
| parent | 7c0ceeeba07e2681e0a16237b900e4eaf5b1b720 (diff) | |
| download | linux-92b51a4da1c46bdd9897dda12ca569856c0a93d7.tar.xz | |
ALSA: seq: Fix race at closing in virmidi driver
commit 2d1b5c08366acd46c35a2e9aba5d650cb5bf5c19 upstream.
The virmidi driver has an open race at closing its assigned rawmidi
device, and this may lead to use-after-free in
snd_seq_deliver_single_event().
Plug the hole by properly protecting the linked list deletion and
calling in the right order in snd_virmidi_input_close().
BugLink: http://lkml.kernel.org/r/CACT4Y+Zd66+w12fNN85-425cVQT=K23kWbhnCEcMB8s3us-Frw@mail.gmail.com
Reported-by: Dmitry Vyukov <dvyukov@google.com>
Tested-by: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: Willy Tarreau <w@1wt.eu>
| -rw-r--r-- | sound/core/seq/seq_virmidi.c | 6 |
1 files changed, 5 insertions, 1 deletions
diff --git a/sound/core/seq/seq_virmidi.c b/sound/core/seq/seq_virmidi.c index 86e7739269ca..081a099a974c 100644 --- a/sound/core/seq/seq_virmidi.c +++ b/sound/core/seq/seq_virmidi.c @@ -253,9 +253,13 @@ static int snd_virmidi_output_open(struct snd_rawmidi_substream *substream) */ static int snd_virmidi_input_close(struct snd_rawmidi_substream *substream) { + struct snd_virmidi_dev *rdev = substream->rmidi->private_data; struct snd_virmidi *vmidi = substream->runtime->private_data; - snd_midi_event_free(vmidi->parser); + + write_lock_irq(&rdev->filelist_lock); list_del(&vmidi->list); + write_unlock_irq(&rdev->filelist_lock); + snd_midi_event_free(vmidi->parser); substream->runtime->private_data = NULL; kfree(vmidi); return 0; |