Subject: CVE-2021-47298: bpf, sockmap: Fix potential memory leak on unlikely error case

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

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

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

bpf, sockmap: Fix potential memory leak on unlikely error case

If skb_linearize is needed and fails we could leak a msg on the error
handling. To fix ensure we kfree the msg block before returning error.
Found during code review.

The Linux kernel CVE team has assigned CVE-2021-47298 to this issue.

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

	Issue introduced in 5.10 with commit 4363023d2668 and fixed in 5.10.54 with commit 715f378f4290
	Issue introduced in 5.10 with commit 4363023d2668 and fixed in 5.13.6 with commit 6c508a1c6c62
	Issue introduced in 5.10 with commit 4363023d2668 and fixed in 5.14 with commit 7e6b27a69167

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-2021-47298
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/skmsg.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/715f378f42909c401ec043f5150c4fdf57fb8889
	https://git.kernel.org/stable/c/6c508a1c6c62793dc6e6872cad4b200097bab7c9
	https://git.kernel.org/stable/c/7e6b27a69167f97c56b5437871d29e9722c3e470