Subject: CVE-2023-52736: ALSA: hda: Do not unset preset when cleaning up codec

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

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

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

ALSA: hda: Do not unset preset when cleaning up codec

Several functions that take part in codec's initialization and removal
are re-used by ASoC codec drivers implementations. Drivers mimic the
behavior of hda_codec_driver_probe/remove() found in
sound/pci/hda/hda_bind.c with their component->probe/remove() instead.

One of the reasons for that is the expectation of
snd_hda_codec_device_new() to receive a valid pointer to an instance of
struct snd_card. This expectation can be met only once sound card
components probing commences.

As ASoC sound card may be unbound without codec device being actually
removed from the system, unsetting ->preset in
snd_hda_codec_cleanup_for_unbind() interferes with module unload -> load
scenario causing null-ptr-deref. Preset is assigned only once, during
device/driver matching whereas ASoC codec driver's module reloading may
occur several times throughout the lifetime of an audio stack.

The Linux kernel CVE team has assigned CVE-2023-52736 to this issue.

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

	Fixed in 5.10.169 with commit 7fc4e7191eae
	Fixed in 5.15.95 with commit e909f5f2aa55
	Fixed in 6.1.13 with commit 427ca2530da8
	Fixed in 6.2 with commit 87978e6ad45a

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-2023-52736
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/pci/hda/hda_bind.c
	sound/pci/hda/hda_codec.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/7fc4e7191eae9d9325511e03deadfdb2224914f8
	https://git.kernel.org/stable/c/e909f5f2aa55a8f9aa6919cce08015cb0e8d4668
	https://git.kernel.org/stable/c/427ca2530da8dc61a42620d7113b05e187b6c2c0
	https://git.kernel.org/stable/c/87978e6ad45a16835cc58234451111091be3c59a