Subject: CVE-2021-47514: devlink: fix netns refcount leak in devlink_nl_cmd_reload()

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

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

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

devlink: fix netns refcount leak in devlink_nl_cmd_reload()

While preparing my patch series adding netns refcount tracking,
I spotted bugs in devlink_nl_cmd_reload()

Some error paths forgot to release a refcount on a netns.

To fix this, we can reduce the scope of get_net()/put_net()
section around the call to devlink_reload().

The Linux kernel CVE team has assigned CVE-2021-47514 to this issue.

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

	Issue introduced in 5.10 with commit ccdf07219da6 and fixed in 5.10.85 with commit 4b7e90672af8
	Issue introduced in 5.10 with commit ccdf07219da6 and fixed in 5.15.8 with commit fe30b70ca84d
	Issue introduced in 5.10 with commit ccdf07219da6 and fixed in 5.16 with commit 4dbb0dad8e63

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-2021-47514
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:
	net/core/devlink.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/4b7e90672af8e0c78205db006f1b0a20ebd07f5f
	https://git.kernel.org/stable/c/fe30b70ca84da9c4aca85c03ad86e7a9b89c5ded
	https://git.kernel.org/stable/c/4dbb0dad8e63fcd0b5a117c2861d2abe7ff5f186