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

From: Dan Carpenter <dan.carpenter@oracle.com>
To: Jaroslav Kysela <perex@perex.cz>
Cc: Armijn Hemel <armijn@tjaldur.nl>,
	alsa-devel@alsa-project.org, kernel-janitors@vger.kernel.org,
	Takashi Iwai <tiwai@suse.com>,
	Allison Randal <allison@lohutok.net>
Subject: [PATCH] ALSA: isa/wavefront: prevent out of bounds write in ioctl
Date: Fri, 1 May 2020 12:40:11 +0300	[thread overview]
Message-ID: <20200501094011.GA960082@mwanda> (raw)

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>
---
This code predates git.

 sound/isa/wavefront/wavefront_synth.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/sound/isa/wavefront/wavefront_synth.c b/sound/isa/wavefront/wavefront_synth.c
index c5b1d5900eed2..d6420d224d097 100644
--- 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;
-- 
2.26.2

