Subject: CVE-2021-47518: nfc: fix potential NULL pointer deref in nfc_genl_dump_ses_done

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

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

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

nfc: fix potential NULL pointer deref in nfc_genl_dump_ses_done

The done() netlink callback nfc_genl_dump_ses_done() should check if
received argument is non-NULL, because its allocation could fail earlier
in dumpit() (nfc_genl_dump_ses()).

The Linux kernel CVE team has assigned CVE-2021-47518 to this issue.

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

	Issue introduced in 3.12 with commit ac22ac466a65 and fixed in 4.4.295 with commit 87cdb8789c38
	Issue introduced in 3.12 with commit ac22ac466a65 and fixed in 4.9.293 with commit 69bb79a8f5bb
	Issue introduced in 3.12 with commit ac22ac466a65 and fixed in 4.14.258 with commit 811a75767477
	Issue introduced in 3.12 with commit ac22ac466a65 and fixed in 4.19.221 with commit 3b861a40325e
	Issue introduced in 3.12 with commit ac22ac466a65 and fixed in 5.4.165 with commit 48fcd08fdbe0
	Issue introduced in 3.12 with commit ac22ac466a65 and fixed in 5.10.85 with commit 83ea620a1be8
	Issue introduced in 3.12 with commit ac22ac466a65 and fixed in 5.15.8 with commit fae9705d2810
	Issue introduced in 3.12 with commit ac22ac466a65 and fixed in 5.16 with commit 4cd8371a234d

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-2021-47518
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/nfc/netlink.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/87cdb8789c38e44ae5454aafe277997c950d00ed
	https://git.kernel.org/stable/c/69bb79a8f5bb9f436b6f1434ca9742591b7bbe18
	https://git.kernel.org/stable/c/811a7576747760bcaf60502f096d1e6e91d566fa
	https://git.kernel.org/stable/c/3b861a40325eac9c4c13b6c53874ad90617e944d
	https://git.kernel.org/stable/c/48fcd08fdbe05e35b650a252ec2a2d96057a1c7a
	https://git.kernel.org/stable/c/83ea620a1be840bf05089a5061fb8323ca42f38c
	https://git.kernel.org/stable/c/fae9705d281091254d4a81fa2da9d22346097dca
	https://git.kernel.org/stable/c/4cd8371a234d051f9c9557fcbb1f8c523b1c0d10