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authorZheyu Ma <zheyuma97@gmail.com>2021-07-14 04:09:22 +0000
committerSam Ravnborg <sam@ravnborg.org>2021-07-19 20:46:32 +0200
commit98a65439172dc69cb16834e62e852afc2adb83ed (patch)
treeabd0b244c63d26fecbb8f577bcf8931fb1059f41 /drivers/video
parent5cc4e71f0199391b0e311c44e79736c13eea269d (diff)
video: fbdev: kyro: fix a DoS bug by restricting user input
The user can pass in any value to the driver through the 'ioctl' interface. The driver dost not check, which may cause DoS bugs. The following log reveals it: divide error: 0000 [#1] PREEMPT SMP KASAN PTI RIP: 0010:SetOverlayViewPort+0x133/0x5f0 drivers/video/fbdev/kyro/STG4000OverlayDevice.c:476 Call Trace: kyro_dev_overlay_viewport_set drivers/video/fbdev/kyro/fbdev.c:378 [inline] kyrofb_ioctl+0x2eb/0x330 drivers/video/fbdev/kyro/fbdev.c:603 do_fb_ioctl+0x1f3/0x700 drivers/video/fbdev/core/fbmem.c:1171 fb_ioctl+0xeb/0x130 drivers/video/fbdev/core/fbmem.c:1185 vfs_ioctl fs/ioctl.c:48 [inline] __do_sys_ioctl fs/ioctl.c:753 [inline] __se_sys_ioctl fs/ioctl.c:739 [inline] __x64_sys_ioctl+0x19b/0x220 fs/ioctl.c:739 do_syscall_64+0x32/0x80 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xae Signed-off-by: Zheyu Ma <zheyuma97@gmail.com> Signed-off-by: Sam Ravnborg <sam@ravnborg.org> Link: https://patchwork.freedesktop.org/patch/msgid/1626235762-2590-1-git-send-email-zheyuma97@gmail.com
Diffstat (limited to 'drivers/video')
-rw-r--r--drivers/video/fbdev/kyro/fbdev.c5
1 files changed, 5 insertions, 0 deletions
diff --git a/drivers/video/fbdev/kyro/fbdev.c b/drivers/video/fbdev/kyro/fbdev.c
index 8fbde92ae8b9..4b8c7c16b1df 100644
--- a/drivers/video/fbdev/kyro/fbdev.c
+++ b/drivers/video/fbdev/kyro/fbdev.c
@@ -372,6 +372,11 @@ static int kyro_dev_overlay_viewport_set(u32 x, u32 y, u32 ulWidth, u32 ulHeight
/* probably haven't called CreateOverlay yet */
return -EINVAL;
+ if (ulWidth == 0 || ulWidth == 0xffffffff ||
+ ulHeight == 0 || ulHeight == 0xffffffff ||
+ (x < 2 && ulWidth + 2 == 0))
+ return -EINVAL;
+
/* Stop Ramdac Output */
DisableRamdacOutput(deviceInfo.pSTGReg);