From: Wei Chen harperchen1110@gmail.com
[ Upstream commit f90bd245de82c095187d8c2cabb8b488a39eaecc ]
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: Wei Chen harperchen1110@gmail.com Signed-off-by: Helge Deller deller@gmx.de Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/video/fbdev/tgafb.c | 3 +++ 1 file changed, 3 insertions(+)
diff --git a/drivers/video/fbdev/tgafb.c b/drivers/video/fbdev/tgafb.c index 14d37c49633c6..b44004880f0d1 100644 --- a/drivers/video/fbdev/tgafb.c +++ b/drivers/video/fbdev/tgafb.c @@ -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;