From: Fullway Wang <fullwaywang@outlook.com>
To: deller@gmx.de, tzimmermann@suse.de, sam@ravnborg.org, javierm@redhat.com
Cc: linux-fbdev@vger.kernel.org, linux-kernel@vger.kernel.org,
fullwaywang@tencent.com, Fullway Wang <fullwaywang@outlook.com>
Subject: [PATCH] video: fbdev: sis: Error out if pixclock equals zero
Date: Thu, 18 Jan 2024 14:24:43 +0800 [thread overview]
Message-ID: <PH7PR20MB5925C492B7F8CDACB2386DB4BF712@PH7PR20MB5925.namprd20.prod.outlook.com> (raw)
The userspace program could pass any values to the driver through
ioctl() interface. If the driver doesn't check the value of pixclock,
it may cause divide-by-zero error.
In sisfb_check_var(), var->pixclock is used as a divisor to caculate
drate before it is checked against zero. Fix this by checking it
at the beginning.
This is similar to CVE-2022-3061 in i740fb which was fixed by
commit 15cf0b8.
Signed-off-by: Fullway Wang <fullwaywang@outlook.com>
---
drivers/video/fbdev/sis/sis_main.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/drivers/video/fbdev/sis/sis_main.c b/drivers/video/fbdev/sis/sis_main.c
index 803ccb6aa479..009bf1d92644 100644
--- a/drivers/video/fbdev/sis/sis_main.c
+++ b/drivers/video/fbdev/sis/sis_main.c
@@ -1444,6 +1444,8 @@ sisfb_check_var(struct fb_var_screeninfo *var, struct fb_info *info)
vtotal = var->upper_margin + var->lower_margin + var->vsync_len;
+ if (!var->pixclock)
+ return -EINVAL;
pixclock = var->pixclock;
if((var->vmode & FB_VMODE_MASK) == FB_VMODE_NONINTERLACED) {
--
2.39.3 (Apple Git-145)
next reply other threads:[~2024-01-18 6:25 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-01-18 6:24 Fullway Wang [this message]
2024-01-21 8:01 ` [PATCH] video: fbdev: sis: Error out if pixclock equals zero Helge Deller
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