From e421946be7d9bf545147bea8419ef8239cb7ca52 Mon Sep 17 00:00:00 2001 From: Fullway Wang Date: Thu, 18 Jan 2024 14:24:43 +0800 Subject: fbdev: sis: Error out if pixclock equals zero 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 Signed-off-by: Helge Deller --- 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) { -- cgit