On Fri, Aug 27, 2021 at 8:37 AM Zubin Mithra zsm@chromium.org wrote:

Syzkaller reported a divide error in snd_pcm_lib_ioctl. fifo_size is of type snd_pcm_uframes_t(unsigned long). If frame_size is 0x100000000, the error occurs.

Fixes: a9960e6a293e ("ALSA: pcm: fix fifo_size frame calculation")

Reviewed-by: Guenter Roeck groeck@chromium.org

Signed-off-by: Zubin Mithra zsm@chromium.org

sound/core/pcm_lib.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/sound/core/pcm_lib.c b/sound/core/pcm_lib.c index 7d5883432085..a144a3f68e9e 100644 --- a/sound/core/pcm_lib.c +++ b/sound/core/pcm_lib.c @@ -1746,7 +1746,7 @@ static int snd_pcm_lib_ioctl_fifo_size(struct snd_pcm_substream *substream, channels = params_channels(params); frame_size = snd_pcm_format_size(format, channels); if (frame_size > 0)

•                   params->fifo_size /= (unsigned)frame_size;
  

•                   params->fifo_size /= frame_size;
    }
    return 0;
  

}

2.33.0.259.gc128427fd7-goog