Subject: CVE-2023-52753: drm/amd/display: Avoid NULL dereference of timing generator

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

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

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

drm/amd/display: Avoid NULL dereference of timing generator

[Why & How]
Check whether assigned timing generator is NULL or not before
accessing its funcs to prevent NULL dereference.

The Linux kernel CVE team has assigned CVE-2023-52753 to this issue.

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

	Fixed in 4.19.300 with commit 09909f515032
	Fixed in 5.4.262 with commit eac3e4760aa1
	Fixed in 5.10.202 with commit 79b6a90f4f24
	Fixed in 5.15.140 with commit 4e497f1acd99
	Fixed in 6.1.64 with commit 8a06894666e0
	Fixed in 6.5.13 with commit 6d8653b1a7a8
	Fixed in 6.6.3 with commit df8bc953eed7
	Fixed in 6.7 with commit b1904ed480ce

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-2023-52753
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/amd/display/dc/core/dc_stream.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/09909f515032fa80b921fd3118efe66b185d10fd
	https://git.kernel.org/stable/c/eac3e4760aa12159f7f5475d55a67b7933abc195
	https://git.kernel.org/stable/c/79b6a90f4f2433312154cd68452b0ba501fa74db
	https://git.kernel.org/stable/c/4e497f1acd99075b13605b2e7fa0cba721a2cfd9
	https://git.kernel.org/stable/c/8a06894666e0b462c9316b26ab615cefdd0d676c
	https://git.kernel.org/stable/c/6d8653b1a7a8dc938b566ae8c4f373b36e792c68
	https://git.kernel.org/stable/c/df8bc953eed72371e43ca407bd063507f760cf89
	https://git.kernel.org/stable/c/b1904ed480cee3f9f4036ea0e36d139cb5fee2d6