linux-cve-announce - CVE-2022-49904: net, neigh: Fix null-ptr-deref in neigh_table

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Message-ID: <2025050102-CVE-2022-49904-5009@gregkh>
Date: Thu,  1 May 2025 16:11:34 +0200
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-cve-announce@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...nel.org>
Subject: CVE-2022-49904: net, neigh: Fix null-ptr-deref in neigh_table_clear()

From: Greg Kroah-Hartman <gregkh@...nel.org>

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

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

net, neigh: Fix null-ptr-deref in neigh_table_clear()

When IPv6 module gets initialized but hits an error in the middle,
kenel panic with:

KASAN: null-ptr-deref in range [0x0000000000000598-0x000000000000059f]
CPU: 1 PID: 361 Comm: insmod
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996)
RIP: 0010:__neigh_ifdown.isra.0+0x24b/0x370
RSP: 0018:ffff888012677908 EFLAGS: 00000202
...
Call Trace:
 <TASK>
 neigh_table_clear+0x94/0x2d0
 ndisc_cleanup+0x27/0x40 [ipv6]
 inet6_init+0x21c/0x2cb [ipv6]
 do_one_initcall+0xd3/0x4d0
 do_init_module+0x1ae/0x670
...
Kernel panic - not syncing: Fatal exception

When ipv6 initialization fails, it will try to cleanup and calls:

neigh_table_clear()
  neigh_ifdown(tbl, NULL)
    pneigh_queue_purge(&tbl->proxy_queue, dev_net(dev == NULL))
    # dev_net(NULL) triggers null-ptr-deref.

Fix it by passing NULL to pneigh_queue_purge() in neigh_ifdown() if dev
is NULL, to make kernel not panic immediately.

The Linux kernel CVE team has assigned CVE-2022-49904 to this issue.


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

	Issue introduced in 4.14.292 with commit 9bbaed571c4bf1b62ac8703cb359dc090efc3455 and fixed in 4.14.299 with commit 0d38b4ca6679e72860ff8730e79bb99d0e9fa3b0
	Issue introduced in 4.19.257 with commit 05fdce1ae744dee43c9181fd063c9c0db4f777f2 and fixed in 4.19.265 with commit b736592de2aa53aee2d48d6b129bc0c892007bbe
	Issue introduced in 5.4.212 with commit 51be9dd391fd25872b95708a0250f2f7722d2d8e and fixed in 5.4.224 with commit b49f6b2f21f543d4dc88fb7b1ec2adccb822f27c
	Issue introduced in 5.10.141 with commit c35adafe42bd6c3bf2aca0a3f523dabc38fc23c8 and fixed in 5.10.154 with commit 1c89642e7f2b7ecc9635610653f5c2f0276c0051
	Issue introduced in 5.15.65 with commit db6fa03d80ab076238fc806c9925d1f8b9639d1b and fixed in 5.15.78 with commit 2b45d6d0c41cb9593868e476681efb1aae5078a1
	Issue introduced in 6.0 with commit 66ba215cb51323e4e55e38fd5f250e0fae0cbc94 and fixed in 6.0.8 with commit a99a8ec4c62180c889482a2ff6465033e0743458
	Issue introduced in 6.0 with commit 66ba215cb51323e4e55e38fd5f250e0fae0cbc94 and fixed in 6.1 with commit f8017317cb0b279b8ab98b0f3901a2e0ac880dad
	Issue introduced in 5.19.7 with commit 2dd5ed474115150d8175825bc3b56c6385c3a83b

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-2022-49904
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/neighbour.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/0d38b4ca6679e72860ff8730e79bb99d0e9fa3b0
	https://git.kernel.org/stable/c/b736592de2aa53aee2d48d6b129bc0c892007bbe
	https://git.kernel.org/stable/c/b49f6b2f21f543d4dc88fb7b1ec2adccb822f27c
	https://git.kernel.org/stable/c/1c89642e7f2b7ecc9635610653f5c2f0276c0051
	https://git.kernel.org/stable/c/2b45d6d0c41cb9593868e476681efb1aae5078a1
	https://git.kernel.org/stable/c/a99a8ec4c62180c889482a2ff6465033e0743458
	https://git.kernel.org/stable/c/f8017317cb0b279b8ab98b0f3901a2e0ac880dad