linux-kernel - [PATCH AUTOSEL 4.19 6/9] fbdev: nvidia: Fix potential divide by zero

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:   Wed, 22 Mar 2023 16:03:06 -0400
From:   Sasha Levin <sashal@...nel.org>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc:     Wei Chen <harperchen1110@...il.com>, Helge Deller <deller@....de>,
        Sasha Levin <sashal@...nel.org>, adaplas@...il.com,
        linux-fbdev@...r.kernel.org, dri-devel@...ts.freedesktop.org
Subject: [PATCH AUTOSEL 4.19 6/9] fbdev: nvidia: Fix potential divide by zero

From: Wei Chen <harperchen1110@...il.com>

[ Upstream commit 92e2a00f2987483e1f9253625828622edd442e61 ]

variable var->pixclock can be set by user. In case it
equals to zero, divide by zero would occur in nvidiafb_set_par.

Similar crashes have happened in other fbdev drivers. There
is no check and modification on var->pixclock along the call
chain to nvidia_check_var and nvidiafb_set_par. We believe it
could also be triggered in driver nvidia from user site.

Signed-off-by: Wei Chen <harperchen1110@...il.com>
Signed-off-by: Helge Deller <deller@....de>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 drivers/video/fbdev/nvidia/nvidia.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/video/fbdev/nvidia/nvidia.c b/drivers/video/fbdev/nvidia/nvidia.c
index fbeeed5afe350..aa502b3ba25ae 100644
--- a/drivers/video/fbdev/nvidia/nvidia.c
+++ b/drivers/video/fbdev/nvidia/nvidia.c
@@ -766,6 +766,8 @@ static int nvidiafb_check_var(struct fb_var_screeninfo *var,
 	int pitch, err = 0;
 
 	NVTRACE_ENTER();
+	if (!var->pixclock)
+		return -EINVAL;
 
 	var->transp.offset = 0;
 	var->transp.length = 0;
-- 
2.39.2