linux-cve-announce - CVE-2022-49622: netfilter: nf_tables: avoid skb access on nf

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Message-ID: <2025022615-CVE-2022-49622-bd19@gregkh>
Date: Wed, 26 Feb 2025 03:23:05 +0100
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-cve-announce@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Subject: CVE-2022-49622: netfilter: nf_tables: avoid skb access on nf_stolen

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

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

netfilter: nf_tables: avoid skb access on nf_stolen

When verdict is NF_STOLEN, the skb might have been freed.

When tracing is enabled, this can result in a use-after-free:
1. access to skb->nf_trace
2. access to skb->mark
3. computation of trace id
4. dump of packet payload

To avoid 1, keep a cached copy of skb->nf_trace in the
trace state struct.
Refresh this copy whenever verdict is != STOLEN.

Avoid 2 by skipping skb->mark access if verdict is STOLEN.

3 is avoided by precomputing the trace id.

Only dump the packet when verdict is not "STOLEN".

The Linux kernel CVE team has assigned CVE-2022-49622 to this issue.

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

	Fixed in 5.18.13 with commit 0016d5d46d7440729a3132f61a8da3bf7f84e2ba
	Fixed in 5.19 with commit e34b9ed96ce3b06c79bf884009b16961ca478f87

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-2022-49622
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_core.c
	net/netfilter/nf_tables_trace.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/0016d5d46d7440729a3132f61a8da3bf7f84e2ba
	https://git.kernel.org/stable/c/e34b9ed96ce3b06c79bf884009b16961ca478f87