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authorTakashi Iwai <tiwai@suse.de>2018-03-10 23:04:23 +0100
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2018-03-22 09:23:30 +0100
commit422d4f1c0711b7563fa9833af971b51114796ad1 (patch)
treecb33233bd54f155a5113653daaf98f554331d005 /sound/core
parentd7230d5286cec2301912714581024e9f0e22083b (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>
Diffstat (limited to 'sound/core')
-rw-r--r--sound/core/oss/pcm_oss.c10
1 files changed, 6 insertions, 4 deletions
diff --git a/sound/core/oss/pcm_oss.c b/sound/core/oss/pcm_oss.c
index 494b7b533366..daa1feac66bf 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)