Subject: CVE-2021-47087: tee: optee: Fix incorrect page free bug

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

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

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

tee: optee: Fix incorrect page free bug

Pointer to the allocated pages (struct page *page) has already
progressed towards the end of allocation. It is incorrect to perform
__free_pages(page, order) using this pointer as we would free any
arbitrary pages. Fix this by stop modifying the page pointer.

The Linux kernel CVE team has assigned CVE-2021-47087 to this issue.

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

	Issue introduced in 5.4.140 with commit 3c712f14d8a9 and fixed in 5.4.169 with commit 806142c805ca
	Issue introduced in 5.10.58 with commit 1340dc3fb75e and fixed in 5.10.89 with commit ad338d825e3f
	Issue introduced in 5.14 with commit ec185dd3ab25 and fixed in 5.15.12 with commit 91e94e42f6fc
	Issue introduced in 5.14 with commit ec185dd3ab25 and fixed in 5.16 with commit 18549bf4b21c
	Issue introduced in 5.13.10 with commit 255e17923b22

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-2021-47087
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/optee/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/806142c805cacd098e61bdc0f72c778a2389fe4a
	https://git.kernel.org/stable/c/ad338d825e3f7b96ee542bf313728af2d19fe9ad
	https://git.kernel.org/stable/c/91e94e42f6fc49635f1a16d8ae3f79552bcfda29
	https://git.kernel.org/stable/c/18549bf4b21c739a9def39f27dcac53e27286ab5