From e1e965156438a3662dbb151d892ada834214c833 Mon Sep 17 00:00:00 2001 From: Zheyu Ma Date: Mon, 4 Apr 2022 16:47:22 +0800 Subject: [PATCH] video: fbdev: arkfb: Error out if 'pixclock' equals zero 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. The following log reveals it: divide error: 0000 [#1] PREEMPT SMP KASAN PTI RIP: 0010:arkfb_set_par+0x10fc/0x24f0 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/arkfb.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/video/fbdev/arkfb.c b/drivers/video/fbdev/arkfb.c index edf169d..eb3e47c 100644 --- a/drivers/video/fbdev/arkfb.c +++ b/drivers/video/fbdev/arkfb.c @@ -566,6 +566,9 @@ static int arkfb_check_var(struct fb_var_screeninfo *var, struct fb_info *info) { int rv, mem, step; + if (!var->pixclock) + return -EINVAL; + /* Find appropriate format */ rv = svga_match_format (arkfb_formats, var, NULL); if (rv < 0) -- 2.7.4