Subject: CVE-2021-46918: dmaengine: idxd: clear MSIX permission entry on shutdown

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

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

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

dmaengine: idxd: clear MSIX permission entry on shutdown

Add disabling/clearing of MSIX permission entries on device shutdown to
mirror the enabling of the MSIX entries on probe. Current code left the
MSIX enabled and the pasid entries still programmed at device shutdown.

The Linux kernel CVE team has assigned CVE-2021-46918 to this issue.

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

	Issue introduced in 5.11 with commit 8e50d392652f and fixed in 5.11.16 with commit c84b8982d7aa
	Issue introduced in 5.11 with commit 8e50d392652f and fixed in 5.12 with commit 6df0e6c57dfc

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-2021-46918
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/dma/idxd/device.c
	drivers/dma/idxd/idxd.h
	drivers/dma/idxd/init.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/c84b8982d7aa9b4717dc36a1c6cbc93ee153b500
	https://git.kernel.org/stable/c/6df0e6c57dfc064af330071f372f11aa8c584997