From 947c2318b072f3d3c30ef75ce38af267c61a580d Mon Sep 17 00:00:00 2001
From: Zheyu Ma <zheyuma97@gmail.com>
Date: Tue, 6 Sep 2022 11:09:13 +0000
Subject: [PATCH] video: fbdev: i740fb: Error out if 'pixclock' equals zero
mainline inclusion
from mainline-v5.18-rc5
commit 15cf0b82271b1823fb02ab8c377badba614d95d5
category: bugfix
bugzilla: https://gitee.com/src-openeuler/kernel/issues/I5OVRU
CVE: CVE-2022-3061
---------------------------
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 error.
Fix this by checking whether 'pixclock' is zero in the function
i740fb_check_var().
The following log reveals it:
divide error: 0000 [#1] PREEMPT SMP KASAN PTI
RIP: 0010:i740fb_decode_var drivers/video/fbdev/i740fb.c:444 [inline]
RIP: 0010:i740fb_set_par+0x272f/0x3bb0 drivers/video/fbdev/i740fb.c:739
Call Trace:
fb_set_var+0x604/0xeb0 drivers/video/fbdev/core/fbmem.c:1036
do_fb_ioctl+0x234/0x670 drivers/video/fbdev/core/fbmem.c:1112
fb_ioctl+0xdd/0x130 drivers/video/fbdev/core/fbmem.c:1191
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:874 [inline]
Signed-off-by: Zheyu Ma <zheyuma97@gmail.com>
Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: Xia Longlong <xialonglong1@huawei.com>
Reviewed-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Reviewed-by: Xiu Jianfeng <xiujianfeng@huawei.com>
Signed-off-by: Yongqiang Liu <liuyongqiang13@huawei.com>
---
drivers/video/fbdev/i740fb.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/drivers/video/fbdev/i740fb.c b/drivers/video/fbdev/i740fb.c
index f6d7b04d6dff..719a3c99f1bd 100644
--- a/drivers/video/fbdev/i740fb.c
+++ b/drivers/video/fbdev/i740fb.c
@@ -656,6 +656,9 @@ static int i740fb_decode_var(const struct fb_var_screeninfo *var,
static int i740fb_check_var(struct fb_var_screeninfo *var, struct fb_info *info)
{
+ if (!var->pixclock)
+ return -EINVAL;
+
switch (var->bits_per_pixel) {
case 8:
var->red.offset = var->green.offset = var->blue.offset = 0;
--
GitLab