snd_pcm_oss_get_formats() has an obvious UAF 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@xxxxxxxxxxxxxxxxxxxxxxxxx
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Takashi Iwai <tiwai@xxxxxxx>
---
sound/core/oss/pcm_oss.c | 10 ++++++----
1 file changed, 6 insertions(+), 4 deletions(-)
diff --git a/sound/core/oss/pcm_oss.c b/sound/core/oss/pcm_oss.c
index b044c0a5a674..02298c9c6020 100644
--- a/sound/core/oss/pcm_oss.c
+++ b/sound/core/oss/pcm_oss.c
@@ -1762,10 +1762,9 @@ 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_c(params, SNDRV_PCM_HW_PARAM_FORMAT);
- kfree(params);
if (err < 0)
- return err;
+ goto error;
+ format_mask = hw_param_mask_c(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);
@@ -1773,7 +1772,10 @@ 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)
--
2.16.2
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