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| author | Takashi Iwai <tiwai@suse.de> | 2016-02-01 12:06:42 +0100 |
|---|---|---|
| committer | Ben Hutchings <ben@decadent.org.uk> | 2016-02-27 14:28:45 +0000 |
| commit | 18f3124816ccc70a7625a145e732ac902aeb924c (patch) | |
| tree | 70fb276ba24c56cf0949bdb48fc8a4600c8ef95b /sound | |
| parent | a6d0c0291601e0af9b0f08dc58be5731f45e8e38 (diff) | |
| download | linux-18f3124816ccc70a7625a145e732ac902aeb924c.tar.gz linux-18f3124816ccc70a7625a145e732ac902aeb924c.tar.bz2 linux-18f3124816ccc70a7625a145e732ac902aeb924c.zip | |
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>
Diffstat (limited to 'sound')
| -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 4b50e604276d..0fa691e01384 100644 --- a/sound/core/seq/seq_virmidi.c +++ b/sound/core/seq/seq_virmidi.c @@ -254,9 +254,13 @@ 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; |