linux-cve-announce - CVE-2023-53831: net: read sk->sk_family once in sk_mc

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Message-ID: <2025120953-CVE-2023-53831-4dc6@gregkh>
Date: Tue,  9 Dec 2025 10:31:15 +0900
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-cve-announce@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...nel.org>
Subject: CVE-2023-53831: net: read sk->sk_family once in sk_mc_loop()

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

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

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

net: read sk->sk_family once in sk_mc_loop()

syzbot is playing with IPV6_ADDRFORM quite a lot these days,
and managed to hit the WARN_ON_ONCE(1) in sk_mc_loop()

We have many more similar issues to fix.

WARNING: CPU: 1 PID: 1593 at net/core/sock.c:782 sk_mc_loop+0x165/0x260
Modules linked in:
CPU: 1 PID: 1593 Comm: kworker/1:3 Not tainted 6.1.40-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/26/2023
Workqueue: events_power_efficient gc_worker
RIP: 0010:sk_mc_loop+0x165/0x260 net/core/sock.c:782
Code: 34 1b fd 49 81 c7 18 05 00 00 4c 89 f8 48 c1 e8 03 42 80 3c 20 00 74 08 4c 89 ff e8 25 36 6d fd 4d 8b 37 eb 13 e8 db 33 1b fd <0f> 0b b3 01 eb 34 e8 d0 33 1b fd 45 31 f6 49 83 c6 38 4c 89 f0 48
RSP: 0018:ffffc90000388530 EFLAGS: 00010246
RAX: ffffffff846d9b55 RBX: 0000000000000011 RCX: ffff88814f884980
RDX: 0000000000000102 RSI: ffffffff87ae5160 RDI: 0000000000000011
RBP: ffffc90000388550 R08: 0000000000000003 R09: ffffffff846d9a65
R10: 0000000000000002 R11: ffff88814f884980 R12: dffffc0000000000
R13: ffff88810dbee000 R14: 0000000000000010 R15: ffff888150084000
FS: 0000000000000000(0000) GS:ffff8881f6b00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000020000180 CR3: 000000014ee5b000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<IRQ>
[<ffffffff8507734f>] ip6_finish_output2+0x33f/0x1ae0 net/ipv6/ip6_output.c:83
[<ffffffff85062766>] __ip6_finish_output net/ipv6/ip6_output.c:200 [inline]
[<ffffffff85062766>] ip6_finish_output+0x6c6/0xb10 net/ipv6/ip6_output.c:211
[<ffffffff85061f8c>] NF_HOOK_COND include/linux/netfilter.h:298 [inline]
[<ffffffff85061f8c>] ip6_output+0x2bc/0x3d0 net/ipv6/ip6_output.c:232
[<ffffffff852071cf>] dst_output include/net/dst.h:444 [inline]
[<ffffffff852071cf>] ip6_local_out+0x10f/0x140 net/ipv6/output_core.c:161
[<ffffffff83618fb4>] ipvlan_process_v6_outbound drivers/net/ipvlan/ipvlan_core.c:483 [inline]
[<ffffffff83618fb4>] ipvlan_process_outbound drivers/net/ipvlan/ipvlan_core.c:529 [inline]
[<ffffffff83618fb4>] ipvlan_xmit_mode_l3 drivers/net/ipvlan/ipvlan_core.c:602 [inline]
[<ffffffff83618fb4>] ipvlan_queue_xmit+0x1174/0x1be0 drivers/net/ipvlan/ipvlan_core.c:677
[<ffffffff8361ddd9>] ipvlan_start_xmit+0x49/0x100 drivers/net/ipvlan/ipvlan_main.c:229
[<ffffffff84763fc0>] netdev_start_xmit include/linux/netdevice.h:4925 [inline]
[<ffffffff84763fc0>] xmit_one net/core/dev.c:3644 [inline]
[<ffffffff84763fc0>] dev_hard_start_xmit+0x320/0x980 net/core/dev.c:3660
[<ffffffff8494c650>] sch_direct_xmit+0x2a0/0x9c0 net/sched/sch_generic.c:342
[<ffffffff8494d883>] qdisc_restart net/sched/sch_generic.c:407 [inline]
[<ffffffff8494d883>] __qdisc_run+0xb13/0x1e70 net/sched/sch_generic.c:415
[<ffffffff8478c426>] qdisc_run+0xd6/0x260 include/net/pkt_sched.h:125
[<ffffffff84796eac>] net_tx_action+0x7ac/0x940 net/core/dev.c:5247
[<ffffffff858002bd>] __do_softirq+0x2bd/0x9bd kernel/softirq.c:599
[<ffffffff814c3fe8>] invoke_softirq kernel/softirq.c:430 [inline]
[<ffffffff814c3fe8>] __irq_exit_rcu+0xc8/0x170 kernel/softirq.c:683
[<ffffffff814c3f09>] irq_exit_rcu+0x9/0x20 kernel/softirq.c:695

The Linux kernel CVE team has assigned CVE-2023-53831 to this issue.


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

	Issue introduced in 2.6.33 with commit 7ad6848c7e81a603605fad3f3575841aab004eea and fixed in 4.14.326 with commit 7586a66b9c4f1b8a825ea1dfa3a91aad5cc7b89b
	Issue introduced in 2.6.33 with commit 7ad6848c7e81a603605fad3f3575841aab004eea and fixed in 4.19.295 with commit e918d0211ffbaf039447334c3460cafee1ce0157
	Issue introduced in 2.6.33 with commit 7ad6848c7e81a603605fad3f3575841aab004eea and fixed in 5.4.257 with commit 41f10a4d78fe69d685a3172e6884297f233dcf95
	Issue introduced in 2.6.33 with commit 7ad6848c7e81a603605fad3f3575841aab004eea and fixed in 5.10.195 with commit 895dc4c47171a20035cdaa8d74c1c1e97f2fc974
	Issue introduced in 2.6.33 with commit 7ad6848c7e81a603605fad3f3575841aab004eea and fixed in 5.15.132 with commit ed4e0adfa407ab65dd73b8862ebf2f308a0349d2
	Issue introduced in 2.6.33 with commit 7ad6848c7e81a603605fad3f3575841aab004eea and fixed in 6.1.54 with commit 9036b6342fcdab190d6edce3dd447859c1de90fc
	Issue introduced in 2.6.33 with commit 7ad6848c7e81a603605fad3f3575841aab004eea and fixed in 6.5.4 with commit b1f5b890b89cb38a6c0bac91984d56cd69808e8c
	Issue introduced in 2.6.33 with commit 7ad6848c7e81a603605fad3f3575841aab004eea and fixed in 6.6 with commit a3e0fdf71bbe031de845e8e08ed7fba49f9c702c

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-2023-53831
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/sock.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/7586a66b9c4f1b8a825ea1dfa3a91aad5cc7b89b
	https://git.kernel.org/stable/c/e918d0211ffbaf039447334c3460cafee1ce0157
	https://git.kernel.org/stable/c/41f10a4d78fe69d685a3172e6884297f233dcf95
	https://git.kernel.org/stable/c/895dc4c47171a20035cdaa8d74c1c1e97f2fc974
	https://git.kernel.org/stable/c/ed4e0adfa407ab65dd73b8862ebf2f308a0349d2
	https://git.kernel.org/stable/c/9036b6342fcdab190d6edce3dd447859c1de90fc
	https://git.kernel.org/stable/c/b1f5b890b89cb38a6c0bac91984d56cd69808e8c
	https://git.kernel.org/stable/c/a3e0fdf71bbe031de845e8e08ed7fba49f9c702c