Commit f90bd245 authored by Wei Chen's avatar Wei Chen Committed by Helge Deller
Browse files

fbdev: tgafb: Fix potential divide by zero 



fb_set_var would by called when user invokes ioctl with cmd
FBIOPUT_VSCREENINFO. User-provided data would finally reach
tgafb_check_var. In case var->pixclock is assigned to zero,
divide by zero would occur when checking whether reciprocal
of var->pixclock is too high.

Similar crashes have happened in other fbdev drivers. There
is no check and modification on var->pixclock along the call
chain to tgafb_check_var. We believe it could also be triggered
in driver tgafb from user site.

Signed-off-by: default avatarWei Chen <harperchen1110@gmail.com>
Signed-off-by: default avatarHelge Deller <deller@gmx.de>
parent 33bf61c0

drivers/video/fbdev/tgafb.c

+3 −0
Original line number Diff line number Diff line
@@ -173,6 +173,9 @@ tgafb_check_var(struct fb_var_screeninfo *var, struct fb_info *info) 
{

	struct tga_par *par = (struct tga_par *)info->par;



	if (!var->pixclock)

		return -EINVAL;



	if (par->tga_type == TGA_TYPE_8PLANE) {

		if (var->bits_per_pixel != 8)

			return -EINVAL;