On 2020/07/15 18:48, Dan Carpenter wrote:
@@ -216,7 +216,7 @@ static void bit_clear_margins(struct vc_data *vc, struct fb_info *info, region.color = color; region.rop = ROP_COPY;
- if (rw && !bottom_only) {
- if ((int) rw > 0 && !bottom_only) { region.dx = info->var.xoffset + rs;
^^^^^^^^^^^^^^^^^^^^^^If you choose a very high positive "rw" then this addition can overflow. info->var.xoffset comes from the user and I don't think it's checked...
Well, I think it would be checked by "struct fb_ops"->check_var hook. For example, vmw_fb_check_var() has
if ((var->xoffset + var->xres) > par->max_width || (var->yoffset + var->yres) > par->max_height) { DRM_ERROR("Requested geom can not fit in framebuffer\n"); return -EINVAL; }
check. Of course, there might be integer overflow in that check... Having sanity check at caller of "struct fb_ops"->check_var might be nice.