diff options
| author | Takashi Iwai <tiwai@suse.de> | 2018-03-10 23:04:23 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2018-03-22 09:17:59 +0100 |
| commit | 238ba452eb4bbd6378f9d4857e0532a806b79013 (patch) | |
| tree | 3ccc770e1d8f7da6c1559ff8b7c712cbc47646e3 | |
| parent | 8f6cfbea4e1621f078a08dfb2b444162ba2f7441 (diff) | |
ALSA: pcm: Fix UAF in snd_pcm_oss_get_formats()
commit 01c0b4265cc16bc1f43f475c5944c55c10d5768f upstream.
snd_pcm_oss_get_formats() has an obvious use-after-free around
snd_mask_test() calls, as spotted by syzbot. The passed format_mask
argument is a pointer to the hw_params object that is freed before the
loop. What a surprise that it has been present since the original
code of decades ago...
Reported-by: syzbot+4090700a4f13fccaf648@syzkaller.appspotmail.com
Cc: <stable@vger.kernel.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | sound/core/oss/pcm_oss.c | 10 |
1 files changed, 6 insertions, 4 deletions
diff --git a/sound/core/oss/pcm_oss.c b/sound/core/oss/pcm_oss.c index 3321348fd86b..3e7c3573871d 100644 --- a/sound/core/oss/pcm_oss.c +++ b/sound/core/oss/pcm_oss.c @@ -1814,10 +1814,9 @@ static int snd_pcm_oss_get_formats(struct snd_pcm_oss_file *pcm_oss_file) return -ENOMEM; _snd_pcm_hw_params_any(params); err = snd_pcm_hw_refine(substream, params); - format_mask = *hw_param_mask(params, SNDRV_PCM_HW_PARAM_FORMAT); - kfree(params); if (err < 0) - return err; + goto error; + format_mask = *hw_param_mask(params, SNDRV_PCM_HW_PARAM_FORMAT); for (fmt = 0; fmt < 32; ++fmt) { if (snd_mask_test(&format_mask, fmt)) { int f = snd_pcm_oss_format_to(fmt); @@ -1825,7 +1824,10 @@ static int snd_pcm_oss_get_formats(struct snd_pcm_oss_file *pcm_oss_file) formats |= f; } } - return formats; + + error: + kfree(params); + return err < 0 ? err : formats; } static int snd_pcm_oss_set_format(struct snd_pcm_oss_file *pcm_oss_file, int format) |