From: Fullway Wang Date: Thu, 18 Jan 2024 03:49:40 +0000 (+0800) Subject: fbdev: savage: Error out if pixclock equals zero X-Git-Tag: v6.6.19~283 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=bc3c2e58d73b28b9a8789fca84778ee165a72d13;p=thirdparty%2Fkernel%2Fstable.git fbdev: savage: Error out if pixclock equals zero [ Upstream commit 04e5eac8f3ab2ff52fa191c187a46d4fdbc1e288 ] 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. Although pixclock is checked in savagefb_decode_var(), but it is not checked properly in savagefb_probe(). Fix this by checking whether pixclock is zero in the function savagefb_check_var() before info->var.pixclock is used as the divisor. 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 Signed-off-by: Sasha Levin --- diff --git a/drivers/video/fbdev/savage/savagefb_driver.c b/drivers/video/fbdev/savage/savagefb_driver.c index b5f84bd4804b8..4ba5cd55e5a52 100644 --- a/drivers/video/fbdev/savage/savagefb_driver.c +++ b/drivers/video/fbdev/savage/savagefb_driver.c @@ -869,6 +869,9 @@ static int savagefb_check_var(struct fb_var_screeninfo *var, DBG("savagefb_check_var"); + if (!var->pixclock) + return -EINVAL; + var->transp.offset = 0; var->transp.length = 0; switch (var->bits_per_pixel) {