ALSA: isa/wavefront: prevent out of bounds write in ioctl

[ Upstream commit 7f0d5053c5a9d23fe5c2d337495a9d79038d267b ]

The "header->number" comes from the ioctl and it needs to be clamped to
prevent out of bounds writes.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Link: https://lore.kernel.org/r/20200501094011.GA960082@mwanda
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/sound/isa/wavefront/wavefront_synth.c b/sound/isa/wavefront/wavefront_synth.c
index c5b1d59..d6420d2 100644 (file)
--- a/sound/isa/wavefront/wavefront_synth.c
+++ b/sound/isa/wavefront/wavefront_synth.c
@@ -1171,7 +1171,10 @@ wavefront_send_alias (snd_wavefront_t *dev, wavefront_patch_info *header)
                                      "alias for %d\n",
                                      header->number,
                                      header->hdr.a.OriginalSample);
-    
+
+       if (header->number >= WF_MAX_SAMPLE)
+               return -EINVAL;
+
        munge_int32 (header->number, &alias_hdr[0], 2);
        munge_int32 (header->hdr.a.OriginalSample, &alias_hdr[2], 2);
        munge_int32 (*((unsigned int *)&header->hdr.a.sampleStartOffset),
@@ -1202,6 +1205,9 @@ wavefront_send_multisample (snd_wavefront_t *dev, wavefront_patch_info *header)
        int num_samples;
        unsigned char *msample_hdr;
 
+       if (header->number >= WF_MAX_SAMPLE)
+               return -EINVAL;
+
        msample_hdr = kmalloc(WF_MSAMPLE_BYTES, GFP_KERNEL);
        if (! msample_hdr)
                return -ENOMEM;