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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org,
        Christian Gromm <christian.gromm@microchip.com>,
        Dan Carpenter <dan.carpenter@oracle.com>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 4.19 30/52] staging: most: sound: add sanity check for function argument
Date:   Fri,  5 Mar 2021 13:22:01 +0100
Message-Id: <20210305120855.157148641@linuxfoundation.org>
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From: Christian Gromm <christian.gromm@microchip.com>

[ 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>
---
 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 89b02fc305b8..fd9245d7eeb9 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];
-- 
2.30.1