Subject: CVE-2021-46919: dmaengine: idxd: fix wq size store permission state

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

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

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

dmaengine: idxd: fix wq size store permission state

WQ size can only be changed when the device is disabled. Current code
allows change when device is enabled but wq is disabled. Change the check
to detect device state.

The Linux kernel CVE team has assigned CVE-2021-46919 to this issue.

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

	Issue introduced in 5.6 with commit c52ca478233c and fixed in 5.10.32 with commit 4ecf25595273
	Issue introduced in 5.6 with commit c52ca478233c and fixed in 5.11.16 with commit 05b7791c4c4a
	Issue introduced in 5.6 with commit c52ca478233c and fixed in 5.12 with commit 0fff71c5a311

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-2021-46919
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/sysfs.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/4ecf25595273203010bc8318c4aee60ad64037ae
	https://git.kernel.org/stable/c/05b7791c4c4aa8304368fdc55ae911f6b34e7281
	https://git.kernel.org/stable/c/0fff71c5a311e1264988179f7dcc217fda15fadd