[PATCH v2] ALSA: pcm: fix divide error in snd_pcm_lib_ioctl

Zubin Mithra zsm at chromium.org
Fri Aug 27 17:37:35 CEST 2021


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")
Signed-off-by: Zubin Mithra <zsm at 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



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