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Commit f453f32f authored by Helge Deller's avatar Helge Deller Committed by Greg Kroah-Hartman
Browse files

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: default avatarHelge Deller <deller@gmx.de>
Reviewed-by: default avatarGeert Uytterhoeven <geert@linux-m68k.org>
Cc: stable@vger.kernel.org # v5.4+
Signed-off-by: default avatarHugo SIMELIERE <hsimeliere.opensource@witekio.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 54eaaac6

drivers/video/fbdev/core/fbmem.c

+11 −0
Original line number Diff line number Diff line
@@ -1006,6 +1006,17 @@ fb_set_var(struct fb_info *info, struct fb_var_screeninfo *var) 
		if (ret)

			goto done;



		/* 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);

			ret = -EINVAL;

			goto done;

		}



		if ((var->activate & FB_ACTIVATE_MASK) == FB_ACTIVATE_NOW) {

			struct fb_var_screeninfo old_var;

			struct fb_videomode mode;