CVE-2021-46926: ALSA: hda: intel-sdw-acpi: harden detection of controller

CVE-2021-46926: ALSA: hda: intel-sdw-acpi: harden detection of controller

[Greg Kroah-Hartman]

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

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

ALSA: hda: intel-sdw-acpi: harden detection of controller

The existing code currently sets a pointer to an ACPI handle before
checking that it's actually a SoundWire controller. This can lead to
issues where the graph walk continues and eventually fails, but the
pointer was set already.

This patch changes the logic so that the information provided to
the caller is set when a controller is found.

The Linux kernel CVE team has assigned CVE-2021-46926 to this issue.


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

	Fixed in 5.15.13 with commit cce476954401
	Fixed in 5.16 with commit 385f287f9853

Please see https://www.kernel.org or 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-2021-46926
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:
	sound/hda/intel-sdw-acpi.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/cce476954401e3421afafb25bbaa926050688b1d
	https://git.kernel.org/stable/c/385f287f9853da402d94278e59f594501c1d1dad