From: Fullway Wang fullwaywang@outlook.com

stable inclusion from stable-v4.19.308 commit 224453de8505aede1890f007be973925a3edf6a1 category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/I9E2Y8 CVE: CVE-2024-26778

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=...

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[ 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 Signed-off-by: Cai Xinchen caixinchen1@huawei.com --- drivers/video/fbdev/savage/savagefb_driver.c | 3 +++ 1 file changed, 3 insertions(+)

diff --git a/drivers/video/fbdev/savage/savagefb_driver.c b/drivers/video/fbdev/savage/savagefb_driver.c index c09d7426cd92..d9eafdb89cea 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) {