Subject: CVE-2023-52773: drm/amd/display: fix a NULL pointer dereference in amdgpu_dm_i2c_xfer()

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

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

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

drm/amd/display: fix a NULL pointer dereference in amdgpu_dm_i2c_xfer()

When ddc_service_construct() is called, it explicitly checks both the
link type and whether there is something on the link which will
dictate whether the pin is marked as hw_supported.

If the pin isn't set or the link is not set (such as from
unloading/reloading amdgpu in an IGT test) then fail the
amdgpu_dm_i2c_xfer() call.

The Linux kernel CVE team has assigned CVE-2023-52773 to this issue.

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

	Issue introduced in 6.0 with commit 22676bc500c2 and fixed in 6.1.64 with commit fb5c134ca589
	Issue introduced in 6.0 with commit 22676bc500c2 and fixed in 6.5.13 with commit 5b14cf37b9f0
	Issue introduced in 6.0 with commit 22676bc500c2 and fixed in 6.6.3 with commit 1d07b7e84276
	Issue introduced in 6.0 with commit 22676bc500c2 and fixed in 6.7 with commit b71f4ade1b89

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-2023-52773
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/amdgpu_dm/amdgpu_dm.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/fb5c134ca589fe670430acc9e7ebf2691ca2476d
	https://git.kernel.org/stable/c/5b14cf37b9f01de0b28c6f8960019d4c7883ce42
	https://git.kernel.org/stable/c/1d07b7e84276777dad3c8cfebdf8e739606f90c9
	https://git.kernel.org/stable/c/b71f4ade1b8900d30c661d6c27f87c35214c398c