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Patch "fbdev: controlfb: Add missing modes to fix out of bounds access" has been added to the 4.14-stable tree

PATCH [email protected] 1 participant 1 message Dec 18, 2017

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This is a note to let you know that I've just added the patch titled

fbdev: controlfb: Add missing modes to fix out of bounds access

to the 4.14-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
fbdev-controlfb-add-missing-modes-to-fix-out-of-bounds-access.patch
and it can be found in the queue-4.14 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

Quoted 1 line

From foo@baz Mon Dec 18 13:28:59 CET 2017

From: Geert Uytterhoeven <[email protected]>
Date: Thu, 9 Nov 2017 18:09:33 +0100
Subject: fbdev: controlfb: Add missing modes to fix out of bounds access

From: Geert Uytterhoeven <[email protected]>

[ 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.

---
 drivers/video/fbdev/controlfb.h |    2 ++
 1 file changed, 2 insertions(+)
drivers/video/fbdev/controlfb.h +2 -0
@@ -141,5 +141,7 @@ static struct max_cmodes control_mac_mod
 	{{ 1, 2}},	/* 1152x870, 75Hz */
 	{{ 0, 1}},	/* 1280x960, 75Hz */
 	{{ 0, 1}},	/* 1280x1024, 75Hz */
+	{{ 1, 2}},	/* 1152x768, 60Hz */
+	{{ 0, 1}},	/* 1600x1024, 60Hz */
 };
 

Patches currently in stable-queue which might be from [email protected] are

queue-4.14/fbdev-controlfb-add-missing-modes-to-fix-out-of-bounds-access.patch queue-4.14/mtd-spi-nor-stm32-quadspi-fix-uninitialized-error-return-code.patch