[PATCH 3.18 26/31] ALSA: isa/wavefront: prevent some out of bound writes

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

3.18-stable review patch.  If anyone has any objections, please let me know.

------------------

[ Upstream commit 84d7a4470dbac0dd9389050100b54a1625d04264 ]

"header->number" can be up to USHRT_MAX and it comes from the ioctl so
it needs to be capped.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 sound/isa/wavefront/wavefront_synth.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/sound/isa/wavefront/wavefront_synth.c b/sound/isa/wavefront/wavefront_synth.c
index e5db001363ee..b5fde9fd1ae9 100644
--- a/sound/isa/wavefront/wavefront_synth.c
+++ b/sound/isa/wavefront/wavefront_synth.c
@@ -785,6 +785,9 @@ wavefront_send_patch (snd_wavefront_t *dev, wavefront_patch_info *header)
 	DPRINT (WF_DEBUG_LOAD_PATCH, "downloading patch %d\n",
 				      header->number);
 
+	if (header->number >= ARRAY_SIZE(dev->patch_status))
+		return -EINVAL;
+
 	dev->patch_status[header->number] |= WF_SLOT_FILLED;
 
 	bptr = buf;
@@ -809,6 +812,9 @@ wavefront_send_program (snd_wavefront_t *dev, wavefront_patch_info *header)
 	DPRINT (WF_DEBUG_LOAD_PATCH, "downloading program %d\n",
 		header->number);
 
+	if (header->number >= ARRAY_SIZE(dev->prog_status))
+		return -EINVAL;
+
 	dev->prog_status[header->number] = WF_SLOT_USED;
 
 	/* XXX need to zero existing SLOT_USED bit for program_status[i]
@@ -898,6 +904,9 @@ wavefront_send_sample (snd_wavefront_t *dev,
 		header->number = x;
 	}
 
+	if (header->number >= WF_MAX_SAMPLE)
+		return -EINVAL;
+
 	if (header->size) {
 
 		/* XXX it's a debatable point whether or not RDONLY semantics
-- 
2.19.1