linux-cve-announce - CVE-2023-52991: net: fix NULL pointer in skb_segment

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Message-ID: <2025032709-CVE-2023-52991-6358@gregkh>
Date: Thu, 27 Mar 2025 17:43:38 +0100
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-cve-announce@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Subject: CVE-2023-52991: net: fix NULL pointer in skb_segment_list

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

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

net: fix NULL pointer in skb_segment_list

Commit 3a1296a38d0c ("net: Support GRO/GSO fraglist chaining.")
introduced UDP listifyed GRO. The segmentation relies on frag_list being
untouched when passing through the network stack. This assumption can be
broken sometimes, where frag_list itself gets pulled into linear area,
leaving frag_list being NULL. When this happens it can trigger
following NULL pointer dereference, and panic the kernel. Reverse the
test condition should fix it.

[19185.577801][    C1] BUG: kernel NULL pointer dereference, address:
...
[19185.663775][    C1] RIP: 0010:skb_segment_list+0x1cc/0x390
...
[19185.834644][    C1] Call Trace:
[19185.841730][    C1]  <TASK>
[19185.848563][    C1]  __udp_gso_segment+0x33e/0x510
[19185.857370][    C1]  inet_gso_segment+0x15b/0x3e0
[19185.866059][    C1]  skb_mac_gso_segment+0x97/0x110
[19185.874939][    C1]  __skb_gso_segment+0xb2/0x160
[19185.883646][    C1]  udp_queue_rcv_skb+0xc3/0x1d0
[19185.892319][    C1]  udp_unicast_rcv_skb+0x75/0x90
[19185.900979][    C1]  ip_protocol_deliver_rcu+0xd2/0x200
[19185.910003][    C1]  ip_local_deliver_finish+0x44/0x60
[19185.918757][    C1]  __netif_receive_skb_one_core+0x8b/0xa0
[19185.927834][    C1]  process_backlog+0x88/0x130
[19185.935840][    C1]  __napi_poll+0x27/0x150
[19185.943447][    C1]  net_rx_action+0x27e/0x5f0
[19185.951331][    C1]  ? mlx5_cq_tasklet_cb+0x70/0x160 [mlx5_core]
[19185.960848][    C1]  __do_softirq+0xbc/0x25d
[19185.968607][    C1]  irq_exit_rcu+0x83/0xb0
[19185.976247][    C1]  common_interrupt+0x43/0xa0
[19185.984235][    C1]  asm_common_interrupt+0x22/0x40
...
[19186.094106][    C1]  </TASK>

The Linux kernel CVE team has assigned CVE-2023-52991 to this issue.


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

	Issue introduced in 5.6 with commit 3a1296a38d0cf62bffb9a03c585cbd5dbf15d596 and fixed in 5.10.167 with commit 6446369fb9f083ce032448c5047da08e298b22e6
	Issue introduced in 5.6 with commit 3a1296a38d0cf62bffb9a03c585cbd5dbf15d596 and fixed in 5.15.92 with commit 046de74f9af92ae9ffce75fa22a1795223f4fb54
	Issue introduced in 5.6 with commit 3a1296a38d0cf62bffb9a03c585cbd5dbf15d596 and fixed in 6.1.10 with commit 888dad6f3e85e3b2f8389bd6478f181efc72534d
	Issue introduced in 5.6 with commit 3a1296a38d0cf62bffb9a03c585cbd5dbf15d596 and fixed in 6.2 with commit 876e8ca8366735a604bac86ff7e2732fc9d85d2d

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-2023-52991
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/skbuff.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/6446369fb9f083ce032448c5047da08e298b22e6
	https://git.kernel.org/stable/c/046de74f9af92ae9ffce75fa22a1795223f4fb54
	https://git.kernel.org/stable/c/888dad6f3e85e3b2f8389bd6478f181efc72534d
	https://git.kernel.org/stable/c/876e8ca8366735a604bac86ff7e2732fc9d85d2d