Subject: CVE-2024-49911: drm/amd/display: Add NULL check for function pointer in dcn20_set_output_transfer_func

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

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

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

drm/amd/display: Add NULL check for function pointer in dcn20_set_output_transfer_func

This commit adds a null check for the set_output_gamma function pointer
in the dcn20_set_output_transfer_func function. Previously,
set_output_gamma was being checked for null at line 1030, but then it
was being dereferenced without any null check at line 1048. This could
potentially lead to a null pointer dereference error if set_output_gamma
is null.

To fix this, we now ensure that set_output_gamma is not null before
dereferencing it. We do this by adding a null check for set_output_gamma
before the call to set_output_gamma at line 1048.

The Linux kernel CVE team has assigned CVE-2024-49911 to this issue.

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

	Fixed in 6.10.14 with commit 02411e935929
	Fixed in 6.11.3 with commit 827380b114f8
	Fixed in 6.12-rc1 with commit 62ed6f0f198d

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-2024-49911
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/hwss/dcn20/dcn20_hwseq.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/02411e9359297512946705b1cd8cf5e6b0806fa0
	https://git.kernel.org/stable/c/827380b114f83c30b3e56d1a675980b6d65f7c88
	https://git.kernel.org/stable/c/62ed6f0f198da04e884062264df308277628004f