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@outlook.com>
Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Fullway Wang 2024-01-18 11:49:40 +08:00 committed by Greg Kroah-Hartman
parent 54b79d8786
commit bc3c2e58d7
1 changed files with 3 additions and 0 deletions

View File

@ -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) {