Subject: CVE-2021-46949: sfc: farch: fix TX queue lookup in TX flush done 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 flush done handling

We're starting from a TXQ instance number ('qid'), not a TXQ type, so
 efx_get_tx_queue() is inappropriate (and could return NULL, leading
 to panics).

The Linux kernel CVE team has assigned CVE-2021-46949 to this issue.

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

	Issue introduced in 5.10 with commit 12804793b17c and fixed in 5.10.36 with commit fb791572d674
	Issue introduced in 5.10 with commit 12804793b17c and fixed in 5.11.20 with commit a1570985ec04
	Issue introduced in 5.10 with commit 12804793b17c and fixed in 5.12.3 with commit 98d911807489
	Issue introduced in 5.10 with commit 12804793b17c and fixed in 5.13 with commit 5b1faa92289b

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-2021-46949
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/fb791572d6747ef385f628450f8d57cd132e6e5a
	https://git.kernel.org/stable/c/a1570985ec04116cc665b760faf666a104154170
	https://git.kernel.org/stable/c/98d91180748986bfb6dfb3e72765f3225719a647
	https://git.kernel.org/stable/c/5b1faa92289b53cad654123ed2bc8e10f6ddd4ac