diff options
| author | Robb Glasser <rglasser@google.com> | 2017-08-11 11:33:31 -0700 |
|---|---|---|
| committer | Moyster <oysterized@gmail.com> | 2017-11-09 13:15:11 +0100 |
| commit | a7af0f1f7823ddabff5f92ad8526cbb3cbcc015e (patch) | |
| tree | 8a89df699a20175c2e3a406ee3c5976d333802b8 | |
| parent | 5043daa42364c738092bfffe5c602540dfff8f0c (diff) | |
ALSA: pcm: prevent UAF in snd_pcm_info
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`.
Bug: 36006981
Signed-off-by: Robb Glasser <rglasser@google.com>
Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
Change-Id: I445d24bc21dc0af6d9522a8daabe64969042236a
| -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 e1e9e0c99..5e95bc66f 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; |