Subject: CVE-2021-47003: dmaengine: idxd: Fix potential null dereference on pointer status

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

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

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

dmaengine: idxd: Fix potential null dereference on pointer status

There are calls to idxd_cmd_exec that pass a null status pointer however
a recent commit has added an assignment to *status that can end up
with a null pointer dereference.  The function expects a null status
pointer sometimes as there is a later assignment to *status where
status is first null checked.  Fix the issue by null checking status
before making the assignment.

Addresses-Coverity: ("Explicit null dereferenced")

The Linux kernel CVE team has assigned CVE-2021-47003 to this issue.

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

	Issue introduced in 5.10.17 with commit 40e3b5c12864 and fixed in 5.10.38 with commit 5756f757c725
	Issue introduced in 5.11 with commit 89e3becd8f82 and fixed in 5.11.22 with commit 2280b4cc29d8
	Issue introduced in 5.11 with commit 89e3becd8f82 and fixed in 5.12.5 with commit 7bc402f843e7
	Issue introduced in 5.11 with commit 89e3becd8f82 and fixed in 5.13 with commit 28ac8e03c43d

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-2021-47003
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

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/5756f757c72501ef1a16f5f63f940623044180e9
	https://git.kernel.org/stable/c/2280b4cc29d8cdd2be3d1b2d1ea4f958e2131c97
	https://git.kernel.org/stable/c/7bc402f843e7817a4a808e7b9ab0bcd7ffd55bfa
	https://git.kernel.org/stable/c/28ac8e03c43dfc6a703aa420d18222540b801120