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| author | Robb Glasser <rglasser@google.com> | 2017-12-05 09:16:55 -0800 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2017-12-16 10:32:27 +0100 |
| commit | 14416b2c878b989674761118db8072bf7f0c9501 (patch) | |
| tree | a8becd7337cbb5b4ba6961560bec280d1fe6b2ca | |
| parent | 346178f1aa5e082f5cfbe94affcbfa1e9d6086df (diff) | |
| download | linux-stable-14416b2c878b989674761118db8072bf7f0c9501.tar.gz linux-stable-14416b2c878b989674761118db8072bf7f0c9501.tar.bz2 linux-stable-14416b2c878b989674761118db8072bf7f0c9501.zip | |
ALSA: pcm: prevent UAF in snd_pcm_info
commit 362bca57f5d78220f8b5907b875961af9436e229 upstream.
When the device descriptor is closed, the `substream->runtime` pointer
is freed. But another thread may be in the ioctl handler, case
SNDRV_CTL_IOCTL_PCM_INFO. This case calls snd_pcm_info_user() which
calls snd_pcm_info() which accesses the now freed `substream->runtime`.
Note: this fixes CVE-2017-0861
Signed-off-by: Robb Glasser <rglasser@google.com>
Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | sound/core/pcm.c | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/sound/core/pcm.c b/sound/core/pcm.c index b917a47a7bb6..314a77a9048e 100644 --- a/sound/core/pcm.c +++ b/sound/core/pcm.c @@ -150,7 +150,9 @@ static int snd_pcm_control_ioctl(struct snd_card *card, err = -ENXIO; goto _error; } + mutex_lock(&pcm->open_mutex); err = snd_pcm_info_user(substream, info); + mutex_unlock(&pcm->open_mutex); _error: mutex_unlock(®ister_mutex); return err; |