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| author | Takashi Iwai <tiwai@suse.de> | 2016-02-01 12:06:42 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2016-02-19 14:22:39 -0800 |
| commit | 14bdca3fa46eb56d2f042ce9f0a8b42f800a9a12 (patch) | |
| tree | 1223e15503bc1261e55eeace114cb68f9b9f0a41 | |
| parent | 4df6314c220c4943f82fdcb882b48561f5ffebbc (diff) | |
| download | linux-stable-14bdca3fa46eb56d2f042ce9f0a8b42f800a9a12.tar.gz linux-stable-14bdca3fa46eb56d2f042ce9f0a8b42f800a9a12.tar.bz2 linux-stable-14bdca3fa46eb56d2f042ce9f0a8b42f800a9a12.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: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -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; |