fbdev: controlfb: Add missing modes to fix out of bounds access
authorGeert Uytterhoeven <geert@linux-m68k.org>
Thu, 9 Nov 2017 17:09:33 +0000 (18:09 +0100)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Wed, 20 Dec 2017 09:10:23 +0000 (10:10 +0100)
[ Upstream commit ac831a379d34109451b3c41a44a20ee10ecb615f ]

Dan's static analysis says:

    drivers/video/fbdev/controlfb.c:560 control_setup()
    error: buffer overflow 'control_mac_modes' 20 <= 21

Indeed, control_mac_modes[] has only 20 elements, while VMODE_MAX is 22,
which may lead to an out of bounds read when parsing vmode commandline
options.

The bug was introduced in v2.4.5.6, when 2 new modes were added to
macmodes.h, but control_mac_modes[] wasn't updated:

https://kernel.opensuse.org/cgit/kernel/diff/include/video/macmodes.h?h=v2.5.2&id=29f279c764808560eaceb88fef36cbc35c529aad

Augment control_mac_modes[] with the two new video modes to fix this.

Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Dan Carpenter <dan.carpenter@oracle.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
drivers/video/fbdev/controlfb.h

index 6026c60fc1007e007ec568d23ad26fa3910795e6..261522fabdac89ae2644089aba612dee880b4d24 100644 (file)
@@ -141,5 +141,7 @@ static struct max_cmodes control_mac_modes[] = {
        {{ 1, 2}},      /* 1152x870, 75Hz */
        {{ 0, 1}},      /* 1280x960, 75Hz */
        {{ 0, 1}},      /* 1280x1024, 75Hz */
+       {{ 1, 2}},      /* 1152x768, 60Hz */
+       {{ 0, 1}},      /* 1600x1024, 60Hz */
 };