This is a note to let you know that I've just added the patch titled
fbdev: savage: Error out if pixclock equals zero
to the 4.19-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
fbdev-savage-error-out-if-pixclock-equals-zero.patch
and it can be found in the queue-4.19 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit f0b2833f25fcc5a45c0e68aa3f499a96ce198d60
Author: Fullway Wang <fullwaywang@xxxxxxxxxxx>
Date: Thu Jan 18 11:49:40 2024 +0800
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 <fullwaywang@xxxxxxxxxxx>
Signed-off-by: Helge Deller <deller@xxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/video/fbdev/savage/savagefb_driver.c b/drivers/video/fbdev/savage/savagefb_driver.c
index c09d7426cd925..d9eafdb89ceaf 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) {
