Subject: CVE-2021-47558: net: stmmac: Disable Tx queues when reconfiguring the interface

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

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

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

net: stmmac: Disable Tx queues when reconfiguring the interface

The Tx queues were not disabled in situations where the driver needed to
stop the interface to apply a new configuration. This could result in a
kernel panic when doing any of the 3 following actions:
* reconfiguring the number of queues (ethtool -L)
* reconfiguring the size of the ring buffers (ethtool -G)
* installing/removing an XDP program (ip l set dev ethX xdp)

Prevent the panic by making sure netif_tx_disable is called when stopping
an interface.

Without this patch, the following kernel panic can be observed when doing
any of the actions above:

Unable to handle kernel paging request at virtual address ffff80001238d040
[....]
 Call trace:
  dwmac4_set_addr+0x8/0x10
  dev_hard_start_xmit+0xe4/0x1ac
  sch_direct_xmit+0xe8/0x39c
  __dev_queue_xmit+0x3ec/0xaf0
  dev_queue_xmit+0x14/0x20
[...]
[ end trace 0000000000000002 ]---

The Linux kernel CVE team has assigned CVE-2021-47558 to this issue.

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

	Issue introduced in 5.10 with commit 0366f7e06a6b and fixed in 5.15.6 with commit a92f0eebb8dc
	Issue introduced in 5.10 with commit 0366f7e06a6b and fixed in 5.16 with commit b270bfe69736

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-2021-47558
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/stmicro/stmmac/stmmac_main.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/a92f0eebb8dc008b9e8c51c6f7b8c93b27a29a43
	https://git.kernel.org/stable/c/b270bfe697367776eca2e6759a71d700fb8d82a2