Subject: CVE-2023-52581: netfilter: nf_tables: fix memleak when more than 255 elements expired

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

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

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

netfilter: nf_tables: fix memleak when more than 255 elements expired

When more than 255 elements expired we're supposed to switch to a new gc
container structure.

This never happens: u8 type will wrap before reaching the boundary
and nft_trans_gc_space() always returns true.

This means we recycle the initial gc container structure and
lose track of the elements that came before.

While at it, don't deref 'gc' after we've passed it to call_rcu.

The Linux kernel CVE team has assigned CVE-2023-52581 to this issue.

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

	Issue introduced in 6.5 with commit 5f68718b34a5 and fixed in 6.5.6 with commit 4aea243b6853
	Issue introduced in 6.5 with commit 5f68718b34a5 and fixed in 6.6 with commit cf5000a7787c
	Issue introduced in 6.4.11 with commit 0624f190b574

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-2023-52581
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:
	include/net/netfilter/nf_tables.h
	net/netfilter/nf_tables_api.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/7cf055b43756b10aa2b851c927c940f5ed652125
	https://git.kernel.org/stable/c/a995a68e8a3b48533e47c856865d109a1f1a9d01
	https://git.kernel.org/stable/c/09c85f2d21ab6b5acba31a037985b13e8e6565b8
	https://git.kernel.org/stable/c/ef99506eaf1dc31feff1adfcfd68bc5535a22171
	https://git.kernel.org/stable/c/7e5d732e6902eb6a37b35480796838a145ae5f07
	https://git.kernel.org/stable/c/4aea243b6853d06c1d160a9955b759189aa02b14
	https://git.kernel.org/stable/c/cf5000a7787cbc10341091d37245a42c119d26c5