Subject: CVE-2021-47445: drm/msm: Fix null pointer dereference on pointer edp

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

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

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

drm/msm: Fix null pointer dereference on pointer edp

The initialization of pointer dev dereferences pointer edp before
edp is null checked, so there is a potential null pointer deference
issue. Fix this by only dereferencing edp after edp has been null
checked.

Addresses-Coverity: ("Dereference before null check")

The Linux kernel CVE team has assigned CVE-2021-47445 to this issue.

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

	Issue introduced in 4.0 with commit ab5b0107ccf3 and fixed in 4.4.290 with commit f175b9a83e5c
	Issue introduced in 4.0 with commit ab5b0107ccf3 and fixed in 4.9.288 with commit bacac7d26849
	Issue introduced in 4.0 with commit ab5b0107ccf3 and fixed in 4.14.252 with commit 0cd063aa0a09
	Issue introduced in 4.0 with commit ab5b0107ccf3 and fixed in 4.19.213 with commit 7f642b93710b
	Issue introduced in 4.0 with commit ab5b0107ccf3 and fixed in 5.4.155 with commit f302be08e3de
	Issue introduced in 4.0 with commit ab5b0107ccf3 and fixed in 5.10.75 with commit 91a340768b01
	Issue introduced in 4.0 with commit ab5b0107ccf3 and fixed in 5.14.14 with commit 46c8ddede027
	Issue introduced in 4.0 with commit ab5b0107ccf3 and fixed in 5.15 with commit 2133c4fc8e13

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-2021-47445
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/msm/edp/edp_ctrl.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/f175b9a83e5c252d7c74acddc792840016caae0a
	https://git.kernel.org/stable/c/bacac7d26849c8e903ceb7466d9ce8dc3c2797eb
	https://git.kernel.org/stable/c/0cd063aa0a09822cc1620fc59a67fe2f9f6338ac
	https://git.kernel.org/stable/c/7f642b93710b6b1119bdff90be01e6b5a2a5d669
	https://git.kernel.org/stable/c/f302be08e3de94db8863a0b2958b2bb3e8e998e6
	https://git.kernel.org/stable/c/91a340768b012f5b910a203a805b97a345b3db37
	https://git.kernel.org/stable/c/46c8ddede0273d1d132beefa9de8b820326982be
	https://git.kernel.org/stable/c/2133c4fc8e1348dcb752f267a143fe2254613b34