[PATCH v2] ALSA: wavefront: Fix integer overflow in sample size validation

[Junrui Luo]

The wavefront_send_sample() function has an integer overflow issue
when validating sample size. The header->size field is u32 but gets
cast to int for comparison with dev->freemem

Fix by using unsigned comparison to avoid integer overflow.

Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Junrui Luo <moonafterrain@xxxxxxxxxxx>
---
Changes in v2:
- Check for negative freemem before size comparison
- Link to v1: https://lore.kernel.org/all/SYBPR01MB7881FA5CEECF0CCEABDD6CC4AFC4A@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx/
---
 sound/isa/wavefront/wavefront_synth.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/sound/isa/wavefront/wavefront_synth.c b/sound/isa/wavefront/wavefront_synth.c
index cd5c177943aa..0d78533e1cfd 100644
--- a/sound/isa/wavefront/wavefront_synth.c
+++ b/sound/isa/wavefront/wavefront_synth.c
@@ -950,9 +950,9 @@ wavefront_send_sample (snd_wavefront_t *dev,
 	if (header->size) {
 		dev->freemem = wavefront_freemem (dev);
 
-		if (dev->freemem < (int)header->size) {
+		if (dev->freemem < 0 || dev->freemem < header->size) {
 			dev_err(dev->card->dev,
-				"insufficient memory to load %d byte sample.\n",
+				"insufficient memory to load %u byte sample.\n",
 				header->size);
 			return -ENOMEM;
 		}
-- 
2.51.1.dirty