staging: most: sound: add sanity check for function argument

[ 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@microchip.com>
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Link: https://lore.kernel.org/r/1612282865-21846-1-git-send-email-christian.gromm@microchip.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/drivers/staging/most/aim-sound/sound.c b/drivers/staging/most/aim-sound/sound.c
index 9c645801cff4dbd18c0da93faefe984e6013a688..532ec0f7100eb48e6bf21324f2db7a26de511313 100644 (file)
--- a/drivers/staging/most/aim-sound/sound.c
+++ b/drivers/staging/most/aim-sound/sound.c
@@ -92,6 +92,8 @@ 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];