[PATCH v2] V4L/DVB (13661): rj54n1cb0c: possible integer overflow fix

[Mikhail Lobanov]

An integer overflow may occur due to arithmetic operation
(multiplication) between value '314572800' and variable 'resize',
where the value comes from '12 * RJ54N1_MAX_WIDTH * (1 << 14)'
and when 'resize' is equal to 16319.

Found by Linux Verification Center (linuxtesting.org) with SVACE.

Fixes: a6b5f2008a3d ("V4L/DVB (13661): rj54n1cb0c: Add cropping, auto white balance, restrict sizes, add platform data")
Signed-off-by: Aleksandr Burakov <a.burakov@xxxxxxxxxxxx>
Signed-off-by: Mikhail Lobanov <m.lobanov@xxxxxxxxxxxx>
---
v1->v2: updated multiplication operation to use shorthand assignment for improved code readability
link to v1: https://lore.kernel.org/lkml/20240917140454.7880-1-a.burakov@xxxxxxxxxxxx/
 drivers/media/i2c/rj54n1cb0c.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/media/i2c/rj54n1cb0c.c b/drivers/media/i2c/rj54n1cb0c.c
index a59db10153cd..a612ec1e7157 100644
--- a/drivers/media/i2c/rj54n1cb0c.c
+++ b/drivers/media/i2c/rj54n1cb0c.c
@@ -776,8 +776,8 @@ static int rj54n1_sensor_scale(struct v4l2_subdev *sd, s32 *in_w, s32 *in_h,
 	}
 
 	/* Antiflicker */
-	peak = 12 * RJ54N1_MAX_WIDTH * (1 << 14) * resize / rj54n1->tgclk_mhz /
-		10000;
+	peak = 12 * RJ54N1_MAX_WIDTH * resize / rj54n1->tgclk_mhz / 10000;
+	peak *= 1 << 14;
 	peak_50 = peak / 6;
 	peak_60 = peak / 5;
 
-- 
2.25.1