[2/4] fbmem: Check virtual screen sizes in fb_set_var()

[2/4] fbmem: Check virtual screen sizes in fb_set_var()

Origin: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit?id=b81212828ad19ab3eccf00626cd04099215060bf
Bug-Debian-Security: https://security-tracker.debian.org/tracker/CVE-2021-33655

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>
Gbp-Pq: Topic bugfix/all
Gbp-Pq: Name fbmem-check-virtual-screen-sizes-in-fb_set_var.patch