Commit 997d86cd authored Jun 29, 2022 by Helge Deller Committed by Greg Kroah-Hartman Jul 12, 2022

fbmem: Check virtual screen sizes in fb_set_var()



commit 6c11df58fd1ac0aefcb3b227f72769272b939e56 upstream.

Verify that the fbdev or drm driver correctly adjusted the virtual
screen sizes. On failure report the failing driver and reject the screen
size change.

Signed-off-by: Helge Deller <deller@gmx.de>
Reviewed-by: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: stable@vger.kernel.org # v5.4+
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

parent 407c1b49

drivers/video/fbdev/core/fbmem.c

+10 −0

Original line number	Diff line number	Diff line
		@@ -1014,6 +1014,16 @@ fb_set_var(struct fb_info info, struct fb_var_screeninfo var)
		if (ret)
		return ret;

		/* verify that virtual resolution >= physical resolution */
		if (var->xres_virtual < var->xres \|\|
		var->yres_virtual < var->yres) {
		pr_warn("WARNING: fbcon: Driver '%s' missed to adjust virtual screen size (%ux%u vs. %ux%u)\n",
		info->fix.id,
		var->xres_virtual, var->yres_virtual,
		var->xres, var->yres);
		return -EINVAL;
		}

		if ((var->activate & FB_ACTIVATE_MASK) != FB_ACTIVATE_NOW)
		return 0;