Subject: CVE-2023-52649: drm/vkms: Avoid reading beyond LUT array

From: Greg Kroah-Hartman <[email-masked]>

Description
===========

In the Linux kernel, the following vulnerability has been resolved:

drm/vkms: Avoid reading beyond LUT array

When the floor LUT index (drm_fixp2int(lut_index) is the last
index of the array the ceil LUT index will point to an entry
beyond the array. Make sure we guard against it and use the
value of the floor LUT index.

v3:
 - Drop bits from commit description that didn't contribute
   anything of value

The Linux kernel CVE team has assigned CVE-2023-52649 to this issue.

Affected and fixed versions
===========================

	Issue introduced in 6.6 with commit db1f254f2cfa and fixed in 6.6.23 with commit 9556c1676730
	Issue introduced in 6.6 with commit db1f254f2cfa and fixed in 6.7.11 with commit 046c1184ce60
	Issue introduced in 6.6 with commit db1f254f2cfa and fixed in 6.8.2 with commit 92800aaeff51
	Issue introduced in 6.6 with commit db1f254f2cfa and fixed in 6.9 with commit 2fee84030d12

Please see https://www.kernel.org for a full list of currently supported
kernel versions by the kernel community.

Unaffected versions might change over time as fixes are backported to
older supported kernel versions.  The official CVE entry at
	https://cve.org/CVERecord/?id=CVE-2023-52649
will be updated if fixes are backported, please check that for the most
up to date information about this issue.

Affected files
==============

The file(s) affected by this issue are:
	drivers/gpu/drm/vkms/vkms_composer.c

Mitigation
==========

The Linux kernel CVE team recommends that you update to the latest
stable kernel version for this, and many other bugfixes.  Individual
changes are never tested alone, but rather are part of a larger kernel
release.  Cherry-picking individual commits is not recommended or
supported by the Linux kernel community at all.  If however, updating to
the latest release is impossible, the individual changes to resolve this
issue can be found at these commits:
	https://git.kernel.org/stable/c/9556c167673057d48ce4a0da675026fe046654c1
	https://git.kernel.org/stable/c/046c1184ce60b0a37d48134f17ddbc1f32ce02bd
	https://git.kernel.org/stable/c/92800aaeff51b8358d1e0a7eb74daf8aa2d7ce9d
	https://git.kernel.org/stable/c/2fee84030d12d9fddfa874e4562d71761a129277