CVE: CVE-2023-53147
Published: 2025-09-15
Description: In the Linux kernel, the following vulnerability has been resolved:

xfrm: add NULL check in xfrm_update_ae_params

Normally, x->replay_esn and x->preplay_esn should be allocated at
xfrm_alloc_replay_state_esn(...) in xfrm_state_construct(...), hence the
xfrm_update_ae_params(...) is okay to update them. However, the current
implementation of xfrm_new_ae(...) allows a malicious user to directly
dereference a NULL pointer and crash the kernel like below.

BUG: kernel NULL pointer dereference, address: [PII_REDACTED]
PGD 8253067 P4D 8253067 PUD 8e0e067 PMD 0
Oops: 0002 [#1] PREEMPT SMP KASAN NOPTI
CPU: 0 PID: 98 Comm: poc.npd Not tainted 6.4.0-rc7-00072-gdad9774deaf1 #8
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.0-0-gd239552ce722-prebuilt.qemu.o4
RIP: 0010:memcpy_orig+0xad/0x140
Code: e8 4c 89 5f e0 48 8d 7f e0 73 d2 83 c2 20 48 29 d6 48 29 d7 83 fa 10 72 34 4c 8b 06 4c 8b 4e 08 c
RSP: 0018:ffff888008f57658 EFLAGS: 00000202
RAX: [PII_REDACTED] RBX: ffff888008bd0000 RCX: ffffffff8238e571
RDX: [PII_REDACTED] RSI: ffff888007f64844 RDI: [PII_REDACTED]
RBP: [PII_REDACTED] R08: [PII_REDACTED] R09: [PII_REDACTED]
R10: [PII_REDACTED] R11: [PII_REDACTED] R12: ffff888008f57818
R13: ffff888007f64aa4 R14: [PII_REDACTED] R15: [PII_REDACTED]
FS: [PII_REDACTED]4013c0(0000) GS:ffff88806d600000(0000) knlGS:[PII_REDACTED]
CS:  0010 DS: 0000 ES: 0000 CR0: [PII_REDACTED]
CR2: [PII_REDACTED] CR3:[PII_REDACTED]4d8000 CR4:[PII_REDACTED]0006f0
Call Trace:
 <TASK>
 ? __die+0x1f/0x70
 ? page_fault_oops+0x1e8/0x500
 ? __pfx_is_prefetch.constprop.0+0x10/0x10
 ? __pfx_page_fault_oops+0x10/0x10
 ? _raw_spin_unlock_irqrestore+0x11/0x40
 ? fixup_exception+0x36/0x460
 ? _raw_spin_unlock_irqrestore+0x11/0x40
 ? exc_page_fault+0x5e/0xc0
 ? asm_exc_page_fault+0x26/0x30
 ? xfrm_update_ae_params+0xd1/0x260
 ? memcpy_orig+0xad/0x140
 ? __pfx__raw_spin_lock_bh+0x10/0x10
 xfrm_update_ae_params+0xe7/0x260
 xfrm_new_ae+0x298/0x4e0
 ? __pfx_xfrm_new_ae+0x10/0x10
 ? __pfx_xfrm_new_ae+0x10/0x10
 xfrm_user_rcv_msg+0x25a/0x410
 ? __pfx_xfrm_user_rcv_msg+0x10/0x10
 ? __alloc_skb+0xcf/0x210
 ? stack_trace_save+0x90/0xd0
 ? filter_irq_stacks+0x1c/0x70
 ? __stack_depot_save+0x39/0x4e0
 ? __kasan_slab_free+0x10a/0x190
 ? kmem_cache_free+0x9c/0x340
 ? netlink_recvmsg+0x23c/0x660
 ? sock_recvmsg+0xeb/0xf0
 ? __sys_recvfrom+0x13c/0x1f0
 ? __x64_sys_recvfrom+0x71/0x90
 ? do_syscall_64+0x3f/0x90
 ? entry_SYSCALL_64_after_hwframe+0x72/0xdc
 ? copyout+0x3e/0x50
 netlink_rcv_skb+0xd6/0x210
 ? __pfx_xfrm_user_rcv_msg+0x10/0x10
 ? __pfx_netlink_rcv_skb+0x10/0x10
 ? __pfx_sock_has_perm+0x10/0x10
 ? mutex_lock+0x8d/0xe0
 ? __pfx_mutex_lock+0x10/0x10
 xfrm_netlink_rcv+0x44/0x50
 netlink_unicast+0x36f/0x4c0
 ? __pfx_netlink_unicast+0x10/0x10
 ? netlink_recvmsg+0x500/0x660
 netlink_sendmsg+0x3b7/0x700

This Null-ptr-deref bug is assigned CVE-2023-3772. And this commit
adds additional NULL check in xfrm_update_ae_params to fix the NPD.
CVSS Score: 5.5 (MEDIUM)
CWE: CWE-476
References: https://git.kernel.org/stable/c/00374d9b6d9f932802b55181be9831aa948e5b7c; https://git.kernel.org/stable/c/075448a2eb753f813fe873cfa52853e9fef8eedb; https://git.kernel.org/stable/c/44f69c96f8a147413c23c68cda4d6fb5e23137cd