From: Wei Chen <harperchen1110@gmail.com>
Date: Wed, 15 Mar 2023 08:33:47 +0000 (+0000)
Subject: fbdev: intelfb: Fix potential divide by zero
X-Git-Tag: baikal/mips/sdk5.8.2~38
X-Git-Url: https://git.baikalelectronics.ru/sdk/?a=commitdiff_plain;h=e0447380961c9400d3a6ebb501b1f6c6247fb79a;p=kernel.git

fbdev: intelfb: Fix potential divide by zero

[ Upstream commit d823685486a3446d061fed7c7d2f80af984f119a ]

Variable var->pixclock is controlled by user and can be assigned
to zero. Without proper check, divide by zero would occur in
intelfbhw_validate_mode and intelfbhw_mode_to_hw.

Error out if var->pixclock is zero.

Signed-off-by: Wei Chen <harperchen1110@gmail.com>
Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---

diff --git a/drivers/video/fbdev/intelfb/intelfbdrv.c b/drivers/video/fbdev/intelfb/intelfbdrv.c
index a76c61512c608..274e6bb4a9610 100644
--- a/drivers/video/fbdev/intelfb/intelfbdrv.c
+++ b/drivers/video/fbdev/intelfb/intelfbdrv.c
@@ -1214,6 +1214,9 @@ static int intelfb_check_var(struct fb_var_screeninfo *var,
 
 	dinfo = GET_DINFO(info);
 
+	if (!var->pixclock)
+		return -EINVAL;
+
 	/* update the pitch */
 	if (intelfbhw_validate_mode(dinfo, var) != 0)
 		return -EINVAL;