Commit 01c0b426 authored by Takashi Iwai's avatar Takashi Iwai

ALSA: pcm: Fix UAF in snd_pcm_oss_get_formats()

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...

Cc: <>
Signed-off-by: default avatarTakashi Iwai <>
parent a2ff19f7
......@@ -1762,10 +1762,9 @@ static int snd_pcm_oss_get_formats(struct snd_pcm_oss_file *pcm_oss_file)
return -ENOMEM;
err = snd_pcm_hw_refine(substream, params);
format_mask = hw_param_mask_c(params, SNDRV_PCM_HW_PARAM_FORMAT);
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;
return err < 0 ? err : formats;
static int snd_pcm_oss_set_format(struct snd_pcm_oss_file *pcm_oss_file, int format)
Markdown is supported
0% or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment