Subject: CVE-2022-49016: net: mdiobus: fix unbalanced node reference count

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

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

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

net: mdiobus: fix unbalanced node reference count

I got the following report while doing device(mscc-miim) load test
with CONFIG_OF_UNITTEST and CONFIG_OF_DYNAMIC enabled:

  OF: ERROR: memory leak, expected refcount 1 instead of 2,
  of_node_get()/of_node_put() unbalanced - destroy cset entry:
  attach overlay node /spi/soc@0/mdio@7107009c/ethernet-phy@0

If the 'fwnode' is not an acpi node, the refcount is get in
fwnode_mdiobus_phy_device_register(), but it has never been
put when the device is freed in the normal path. So call
fwnode_handle_put() in phy_device_release() to avoid leak.

If it's an acpi node, it has never been get, but it's put
in the error path, so call fwnode_handle_get() before
phy_device_register() to keep get/put operation balanced.

The Linux kernel CVE team has assigned CVE-2022-49016 to this issue.

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

	Issue introduced in 5.14 with commit bc1bee3b87ee and fixed in 5.15.82 with commit 543d917f691a
	Issue introduced in 5.14 with commit bc1bee3b87ee and fixed in 6.0.12 with commit 2708b3574404
	Issue introduced in 5.14 with commit bc1bee3b87ee and fixed in 6.1 with commit cdde1560118f

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-2022-49016
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/mdio/fwnode_mdio.c
	drivers/net/phy/phy_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/543d917f691ab06885ee779c862065899eaa4251
	https://git.kernel.org/stable/c/2708b357440427d6a9fee667eb7b8307f4625adc
	https://git.kernel.org/stable/c/cdde1560118f82498fc9e9a7c1ef7f0ef7755891