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author | Robb Glasser <rglasser@google.com> | 2017-12-05 20:16:55 +0300 |
---|---|---|
committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2017-12-14 11:52:54 +0300 |
commit | 0482dcd51004920b13b59995b7afb66df49937da (patch) | |
tree | 3592386ea45e7ae178dfba73496206eee038d6e3 /sound/core | |
parent | c6705e4c64eb549c1eb86007438034dd7b7a6129 (diff) | |
download | linux-0482dcd51004920b13b59995b7afb66df49937da.tar.xz |
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/core')
-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 7eadb7fd8074..7fea724d093a 100644 --- a/sound/core/pcm.c +++ b/sound/core/pcm.c @@ -153,7 +153,9 @@ 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; |