Message-ID: <2025122428-CVE-2023-54004-34a0@gregkh>
Date: Wed, 24 Dec 2025 11:56:48 +0100
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-cve-announce@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...nel.org>
Subject: CVE-2023-54004: udplite: Fix NULL pointer dereference in __sk_mem_raise_allocated().

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

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

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

udplite: Fix NULL pointer dereference in __sk_mem_raise_allocated().

syzbot reported [0] a null-ptr-deref in sk_get_rmem0() while using
IPPROTO_UDPLITE (0x88):

  14:25:52 executing program 1:
  r0 = socket$inet6(0xa, 0x80002, 0x88)

We had a similar report [1] for probably sk_memory_allocated_add()
in __sk_mem_raise_allocated(), and commit c915fe13cbaa ("udplite: fix
NULL pointer dereference") fixed it by setting .memory_allocated for
udplite_prot and udplitev6_prot.

To fix the variant, we need to set either .sysctl_wmem_offset or
.sysctl_rmem.

Now UDP and UDPLITE share the same value for .memory_allocated, so we
use the same .sysctl_wmem_offset for UDP and UDPLITE.

[0]:
general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] PREEMPT SMP KASAN
KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]
CPU: 0 PID: 6829 Comm: syz-executor.1 Not tainted 6.4.0-rc2-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/28/2023
RIP: 0010:sk_get_rmem0 include/net/sock.h:2907 [inline]
RIP: 0010:__sk_mem_raise_allocated+0x806/0x17a0 net/core/sock.c:3006
Code: c1 ea 03 80 3c 02 00 0f 85 23 0f 00 00 48 8b 44 24 08 48 8b 98 38 01 00 00 48 b8 00 00 00 00 00 fc ff df 48 89 da 48 c1 ea 03 <0f> b6 14 02 48 89 d8 83 e0 07 83 c0 03 38 d0 0f 8d 6f 0a 00 00 8b
RSP: 0018:ffffc90005d7f450 EFLAGS: 00010246
RAX: dffffc0000000000 RBX: 0000000000000000 RCX: ffffc90004d92000
RDX: 0000000000000000 RSI: ffffffff88066482 RDI: ffffffff8e2ccbb8
RBP: ffff8880173f7000 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000030000
R13: 0000000000000001 R14: 0000000000000340 R15: 0000000000000001
FS:  0000000000000000(0000) GS:ffff8880b9800000(0063) knlGS:00000000f7f1cb40
CS:  0010 DS: 002b ES: 002b CR0: 0000000080050033
CR2: 000000002e82f000 CR3: 0000000034ff0000 CR4: 00000000003506f0
Call Trace:
 <TASK>
 __sk_mem_schedule+0x6c/0xe0 net/core/sock.c:3077
 udp_rmem_schedule net/ipv4/udp.c:1539 [inline]
 __udp_enqueue_schedule_skb+0x776/0xb30 net/ipv4/udp.c:1581
 __udpv6_queue_rcv_skb net/ipv6/udp.c:666 [inline]
 udpv6_queue_rcv_one_skb+0xc39/0x16c0 net/ipv6/udp.c:775
 udpv6_queue_rcv_skb+0x194/0xa10 net/ipv6/udp.c:793
 __udp6_lib_mcast_deliver net/ipv6/udp.c:906 [inline]
 __udp6_lib_rcv+0x1bda/0x2bd0 net/ipv6/udp.c:1013
 ip6_protocol_deliver_rcu+0x2e7/0x1250 net/ipv6/ip6_input.c:437
 ip6_input_finish+0x150/0x2f0 net/ipv6/ip6_input.c:482
 NF_HOOK include/linux/netfilter.h:303 [inline]
 NF_HOOK include/linux/netfilter.h:297 [inline]
 ip6_input+0xa0/0xd0 net/ipv6/ip6_input.c:491
 ip6_mc_input+0x40b/0xf50 net/ipv6/ip6_input.c:585
 dst_input include/net/dst.h:468 [inline]
 ip6_rcv_finish net/ipv6/ip6_input.c:79 [inline]
 NF_HOOK include/linux/netfilter.h:303 [inline]
 NF_HOOK include/linux/netfilter.h:297 [inline]
 ipv6_rcv+0x250/0x380 net/ipv6/ip6_input.c:309
 __netif_receive_skb_one_core+0x114/0x180 net/core/dev.c:5491
 __netif_receive_skb+0x1f/0x1c0 net/core/dev.c:5605
 netif_receive_skb_internal net/core/dev.c:5691 [inline]
 netif_receive_skb+0x133/0x7a0 net/core/dev.c:5750
 tun_rx_batched+0x4b3/0x7a0 drivers/net/tun.c:1553
 tun_get_user+0x2452/0x39c0 drivers/net/tun.c:1989
 tun_chr_write_iter+0xdf/0x200 drivers/net/tun.c:2035
 call_write_iter include/linux/fs.h:1868 [inline]
 new_sync_write fs/read_write.c:491 [inline]
 vfs_write+0x945/0xd50 fs/read_write.c:584
 ksys_write+0x12b/0x250 fs/read_write.c:637
 do_syscall_32_irqs_on arch/x86/entry/common.c:112 [inline]
 __do_fast_syscall_32+0x65/0xf0 arch/x86/entry/common.c:178
 do_fast_syscall_32+0x33/0x70 arch/x86/entry/common.c:203
 entry_SYSENTER_compat_after_hwframe+0x70/0x82
RIP: 0023:0xf7f21579
Code: b8 01 10 06 03 74 b4 01 10 07 03 74 b0 01 10 08 03 74 d8 01 00 00 00 00 00 00 00 00 00 00 00 00 00 51 52 55 89 e5 0f 34 cd 80 <5d> 5a 59 c3 90 90 90 90 8d b4 26 00 00 00 00 8d b4 26 00 00 00 00
RSP: 002b:00000000f7f1c590 EFLAGS: 00000282 ORIG_RAX: 0000000000000004
RAX: ffffffffffffffda RBX: 00000000000000c8 RCX: 0000000020000040
RDX: 0000000000000083 RSI: 00000000f734e000 RDI: 0000000000000000
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000296 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
 </TASK>
Modules linked in:

The Linux kernel CVE team has assigned CVE-2023-54004 to this issue.


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

	Issue introduced in 4.10 with commit 850cbaddb52dfd4e0c7cabe2c168dd34b44ae0b9 and fixed in 4.19.284 with commit cc56de054d828935aa37734b479f82fa34b5f9bd
	Issue introduced in 4.10 with commit 850cbaddb52dfd4e0c7cabe2c168dd34b44ae0b9 and fixed in 5.4.244 with commit 7e3ae83371a4809da6fa3f10ccc430eecef3034a
	Issue introduced in 4.10 with commit 850cbaddb52dfd4e0c7cabe2c168dd34b44ae0b9 and fixed in 5.10.181 with commit 5014b64e369bdf997935b132a1ac4d64b6e47ad4
	Issue introduced in 4.10 with commit 850cbaddb52dfd4e0c7cabe2c168dd34b44ae0b9 and fixed in 5.15.114 with commit 387bd0a3af3bdd2b16f8dbef0c9fcccac63000a4
	Issue introduced in 4.10 with commit 850cbaddb52dfd4e0c7cabe2c168dd34b44ae0b9 and fixed in 6.1.31 with commit 2a112f04629f7839e7cb509b27b8d3b735afe255
	Issue introduced in 4.10 with commit 850cbaddb52dfd4e0c7cabe2c168dd34b44ae0b9 and fixed in 6.3.5 with commit f04c8eaf45e7dcdfccba936506b1ec592a369fb9
	Issue introduced in 4.10 with commit 850cbaddb52dfd4e0c7cabe2c168dd34b44ae0b9 and fixed in 6.4 with commit ad42a35bdfc6d3c0fc4cb4027d7b2757ce665665

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-2023-54004
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/ipv4/udplite.c
	net/ipv6/udplite.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/cc56de054d828935aa37734b479f82fa34b5f9bd
	https://git.kernel.org/stable/c/7e3ae83371a4809da6fa3f10ccc430eecef3034a
	https://git.kernel.org/stable/c/5014b64e369bdf997935b132a1ac4d64b6e47ad4
	https://git.kernel.org/stable/c/387bd0a3af3bdd2b16f8dbef0c9fcccac63000a4
	https://git.kernel.org/stable/c/2a112f04629f7839e7cb509b27b8d3b735afe255
	https://git.kernel.org/stable/c/f04c8eaf45e7dcdfccba936506b1ec592a369fb9
	https://git.kernel.org/stable/c/ad42a35bdfc6d3c0fc4cb4027d7b2757ce665665

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