Subject: CVE-2021-47601: tee: amdtee: fix an IS_ERR() vs NULL bug

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

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

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

tee: amdtee: fix an IS_ERR() vs NULL bug

The __get_free_pages() function does not return error pointers it returns
NULL so fix this condition to avoid a NULL dereference.

The Linux kernel CVE team has assigned CVE-2021-47601 to this issue.

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

	Issue introduced in 5.6 with commit 757cc3e9ff1d and fixed in 5.10.88 with commit 640e28d618e8
	Issue introduced in 5.6 with commit 757cc3e9ff1d and fixed in 5.15.11 with commit 832f3655c613
	Issue introduced in 5.6 with commit 757cc3e9ff1d and fixed in 5.16 with commit 9d7482771fac

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-2021-47601
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/tee/amdtee/core.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/640e28d618e82be78fb43b4bf5113bc90d6aa442
	https://git.kernel.org/stable/c/832f3655c6138c23576ed268e31cc76e0f05f2b1
	https://git.kernel.org/stable/c/9d7482771fac8d8e38e763263f2ca0ca12dd22c6