diff options
| author | Robb Glasser <rglasser@google.com> | 2017-12-05 09:16:55 -0800 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2017-12-14 09:28:12 +0100 |
| commit | 45ddff3ce4e9a3d7e935d5b596686d9e176ed4a9 (patch) | |
| tree | 0da5e6d0740a6f3342f04680d4685f33632478c0 /sound | |
| parent | 8974b0320cc83b99a86d5fcca51e7c875254ec0d (diff) | |
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>
Diffstat (limited to 'sound')
| -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 8e980aa678d0..074363b63cc4 100644 --- a/sound/core/pcm.c +++ b/sound/core/pcm.c @@ -149,7 +149,9 @@ 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; |