Subject: CVE-2021-47332: ALSA: usx2y: Don't call free_pages_exact() with NULL address

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

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

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

ALSA: usx2y: Don't call free_pages_exact() with NULL address

Unlike some other functions, we can't pass NULL pointer to
free_pages_exact().  Add a proper NULL check for avoiding possible
Oops.

The Linux kernel CVE team has assigned CVE-2021-47332 to this issue.

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

	Fixed in 5.4.134 with commit 88262229b778
	Fixed in 5.10.52 with commit 7d7f30cf182e
	Fixed in 5.12.19 with commit bee295f5e035
	Fixed in 5.13.4 with commit 82e5ee742fdd
	Fixed in 5.14 with commit cae0cf651adc

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-2021-47332
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/usb/usx2y/usb_stream.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/88262229b778f4f7a896da828d966f94dcb35d19
	https://git.kernel.org/stable/c/7d7f30cf182e55023fa8fde4c084b2d37c6be69d
	https://git.kernel.org/stable/c/bee295f5e03510252d18b25cc1d26230256eb87a
	https://git.kernel.org/stable/c/82e5ee742fdd8874fe996181b87fafe1eb5f1196
	https://git.kernel.org/stable/c/cae0cf651adccee2c3f376e78f30fbd788d0829f