From: Zheyu Ma <zheyuma97@xxxxxxxxx> [ Upstream commit 98a65439172dc69cb16834e62e852afc2adb83ed ] 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@xxxxxxxxx> Signed-off-by: Sam Ravnborg <sam@xxxxxxxxxxxx> Link: https://patchwork.freedesktop.org/patch/msgid/1626235762-2590-1-git-send-email-zheyuma97@xxxxxxxxx Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- drivers/video/fbdev/kyro/fbdev.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/drivers/video/fbdev/kyro/fbdev.c b/drivers/video/fbdev/kyro/fbdev.c index a7bd9f25911b..d7aa431e6846 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); -- 2.30.2
