]> git.proxmox.com Git - mirror_ubuntu-eoan-kernel.git/commit
drm/dumb-buffers: Integer overflow in drm_mode_create_ioctl()
authorDan Carpenter <dan.carpenter@oracle.com>
Wed, 16 May 2018 14:00:26 +0000 (17:00 +0300)
committerDaniel Vetter <daniel.vetter@ffwll.ch>
Wed, 16 May 2018 15:56:06 +0000 (17:56 +0200)
commit2b6207291b7b277a5df9d1aab44b56815a292dba
treee82d043e6e1cdd9a0a94b95023e8cd786d8217de
parent72cb0d893343cd33e6ab62cf26f2625d5d3532c9
drm/dumb-buffers: Integer overflow in drm_mode_create_ioctl()

There is a comment here which says that DIV_ROUND_UP() and that's where
the problem comes from.  Say you pick:

args->bpp = UINT_MAX - 7;
args->width = 4;
args->height = 1;

The integer overflow in DIV_ROUND_UP() means "cpp" is UINT_MAX / 8 and
because of how we picked args->width that means cpp < UINT_MAX / 4.

I've fixed it by preventing the integer overflow in DIV_ROUND_UP().  I
removed the check for !cpp because it's not possible after this change.
I also changed all the 0xffffffffU references to U32_MAX.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20180516140026.GA19340@mwanda
drivers/gpu/drm/drm_dumb_buffers.c