ALSA: compress: prevent potential divide by zero bugs

The problem is seen in the q6asm_dai_compr_set_params() function:

	ret = q6asm_map_memory_regions(dir, prtd->audio_client, prtd->phys,
				       (prtd->pcm_size / prtd->periods),
                                        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
				       prtd->periods);

In this code prtd->pcm_size is the buffer_size and prtd->periods comes
from params->buffer.fragments.  If we allow the number of fragments to
be zero then it results in a divide by zero bug.  One possible fix would
be to use prtd->pcm_count directly instead of using the division to
re-calculate it.  But I decided that it doesn't really make sense to
allow zero fragments.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

diff --git a/sound/core/compress_offload.c b/sound/core/compress_offload.c
index a5b09e75e7874bb6a1facc9a9fd70e6fdac10791..f7d2b373da0aaebd869b06773c24b7994c0cb472 100644 (file)
--- a/sound/core/compress_offload.c
+++ b/sound/core/compress_offload.c
@@ -541,7 +541,8 @@ static int snd_compress_check_input(struct snd_compr_params *params)
 {
        /* first let's check the buffer parameter's */
        if (params->buffer.fragment_size == 0 ||
-           params->buffer.fragments > INT_MAX / params->buffer.fragment_size)
+           params->buffer.fragments > INT_MAX / params->buffer.fragment_size ||
+           params->buffer.fragments == 0)
                return -EINVAL;
 
        /* now codec parameters */