[PATCH AUTOSEL 4.19 10/26] staging: most: sound: add sanity check for function argument

[Sasha Levin]

From: Christian Gromm <christian.gromm@xxxxxxxxxxxxx>

[ Upstream commit 45b754ae5b82949dca2b6e74fa680313cefdc813 ]

This patch checks the function parameter 'bytes' before doing the
subtraction to prevent memory corruption.

Signed-off-by: Christian Gromm <christian.gromm@xxxxxxxxxxxxx>
Reported-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
Link: https://lore.kernel.org/r/1612282865-21846-1-git-send-email-christian.gromm@xxxxxxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 drivers/staging/most/sound/sound.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/staging/most/sound/sound.c b/drivers/staging/most/sound/sound.c
index 89b02fc305b8b..fd9245d7eeb9a 100644
--- a/drivers/staging/most/sound/sound.c
+++ b/drivers/staging/most/sound/sound.c
@@ -86,6 +86,8 @@ static void swap_copy24(u8 *dest, const u8 *source, unsigned int bytes)
 {
 	unsigned int i = 0;
 
+	if (bytes < 2)
+		return;
 	while (i < bytes - 2) {
 		dest[i] = source[i + 2];
 		dest[i + 1] = source[i + 1];
-- 
2.27.0