Subject: CVE-2021-47368: enetc: Fix illegal access when reading affinity_hint

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

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

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

enetc: Fix illegal access when reading affinity_hint

irq_set_affinity_hit() stores a reference to the cpumask_t
parameter in the irq descriptor, and that reference can be
accessed later from irq_affinity_hint_proc_show(). Since
the cpu_mask parameter passed to irq_set_affinity_hit() has
only temporary storage (it's on the stack memory), later
accesses to it are illegal. Thus reads from the corresponding
procfs affinity_hint file can result in paging request oops.

The issue is fixed by the get_cpu_mask() helper, which provides
a permanent storage for the cpumask_t parameter.

The Linux kernel CVE team has assigned CVE-2021-47368 to this issue.

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

	Issue introduced in 5.1 with commit d4fd0404c1c9 and fixed in 5.4.150 with commit 4c4c3052911b
	Issue introduced in 5.1 with commit d4fd0404c1c9 and fixed in 5.10.70 with commit 6c3f1b741c6c
	Issue introduced in 5.1 with commit d4fd0404c1c9 and fixed in 5.14.9 with commit 6f329d9da2a5
	Issue introduced in 5.1 with commit d4fd0404c1c9 and fixed in 5.15 with commit 7237a494decf

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-2021-47368
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/net/ethernet/freescale/enetc/enetc.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/4c4c3052911b577920353a7646e4883d5da40c28
	https://git.kernel.org/stable/c/6c3f1b741c6c2914ea120e3a5790d3e900152f7b
	https://git.kernel.org/stable/c/6f329d9da2a5ae032fcde800a99b118124ed5270
	https://git.kernel.org/stable/c/7237a494decfa17d0b9d0076e6cee3235719de90