Subject: CVE-2021-46948: sfc: farch: fix TX queue lookup in TX event handling

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

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

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

sfc: farch: fix TX queue lookup in TX event handling

We're starting from a TXQ label, not a TXQ type, so
 efx_channel_get_tx_queue() is inappropriate (and could return NULL,
 leading to panics).

The Linux kernel CVE team has assigned CVE-2021-46948 to this issue.

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

	Issue introduced in 5.10 with commit 12804793b17c and fixed in 5.10.36 with commit bf2b941d0a6f
	Issue introduced in 5.10 with commit 12804793b17c and fixed in 5.11.20 with commit 35c7a83ad1bb
	Issue introduced in 5.10 with commit 12804793b17c and fixed in 5.12.3 with commit e531db1ea6f9
	Issue introduced in 5.10 with commit 12804793b17c and fixed in 5.13 with commit 83b09a180741

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-2021-46948
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/sfc/farch.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/bf2b941d0a6f2d3b9f5fa3c4c21bdd54f71ce253
	https://git.kernel.org/stable/c/35c7a83ad1bb1d48ae249346e61b1132bcbf9052
	https://git.kernel.org/stable/c/e531db1ea6f98c9612cb2de093a107c7eadfb96c
	https://git.kernel.org/stable/c/83b09a1807415608b387c7bc748d329fefc5617e