From 213e2df4733275165038d77289812d4473b0b010 Mon Sep 17 00:00:00 2001 From: Zheyu Ma Date: Mon, 4 Apr 2022 16:47:19 +0800 Subject: [PATCH] video: fbdev: kyro: Error out if 'lineclock' equals zero The userspace program could pass any values to the driver through ioctl() interface. If the driver doesn't check the value of 'lineclock', it may cause divide error. Fix this by checking whether 'lineclock' is zero. The following log reveals it: divide error: 0000 [#1] PREEMPT SMP KASAN PTI RIP: 0010:kyrofb_set_par+0x30d/0xd80 Call Trace: fb_set_var+0x604/0xeb0 do_fb_ioctl+0x234/0x670 fb_ioctl+0xdd/0x130 do_syscall_64+0x3b/0x90 Signed-off-by: Zheyu Ma Signed-off-by: Helge Deller --- drivers/video/fbdev/kyro/fbdev.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/video/fbdev/kyro/fbdev.c b/drivers/video/fbdev/kyro/fbdev.c index 25801e8e3f74a..d57772f96ad26 100644 --- a/drivers/video/fbdev/kyro/fbdev.c +++ b/drivers/video/fbdev/kyro/fbdev.c @@ -494,6 +494,8 @@ static int kyrofb_set_par(struct fb_info *info) info->var.hsync_len + info->var.left_margin)) / 1000; + if (!lineclock) + return -EINVAL; /* time for a frame in ns (precision in 32bpp) */ frameclock = lineclock * (info->var.yres + -- 2.30.2