Description

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

apparmor: Fix null pointer deref when receiving skb during sock creation

The panic below is observed when receiving ICMP packets with secmark set
while an ICMP raw socket is being created. SK_CTX(sk)->label is updated
in apparmor_socket_post_create(), but the packet is delivered to the
socket before that, causing the null pointer dereference.
Drop the packet if label context is not set.

BUG: kernel NULL pointer dereference, address: 000000000000004c
#PF: supervisor read access in kernel mode
#PF: error_code(0x0000) - not-present page
PGD 0 P4D 0
Oops: 0000 [#1] PREEMPT SMP NOPTI
CPU: 0 PID: 407 Comm: a.out Not tainted 6.4.12-arch1-1 #1 3e6fa2753a2d75925c34ecb78e22e85a65d083df
Hardware name: VMware, Inc. VMware Virtual Platform/440BX Desktop Reference Platform, BIOS 6.00 05/28/2020
RIP: 0010:aa_label_next_confined+0xb/0x40
Code: 00 00 48 89 ef e8 d5 25 0c 00 e9 66 ff ff ff 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 66 0f 1f 00 0f 1f 44 00 00 89 f0 <8b> 77 4c 39 c6 7e 1f 48 63 d0 48 8d 14 d7 eb 0b 83 c0 01 48 83 c2
RSP: 0018:ffffa92940003b08 EFLAGS: 00010246
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 000000000000000e
RDX: ffffa92940003be8 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffff8b57471e7800 R08: ffff8b574c642400 R09: 0000000000000002
R10: ffffffffbd820eeb R11: ffffffffbeb7ff00 R12: ffff8b574c642400
R13: 0000000000000001 R1...

Classification

CVE ID: CVE-2023-52889

Affected Products

Vendor: Linux

Product: Linux

Exploit Prediction Scoring System (EPSS)

EPSS Score: 0.04% (probability of being exploited)

EPSS Percentile: 5.08% (scored less or equal to compared to others)

EPSS Date: 2025-02-04 (when was this score calculated)

References

https://git.kernel.org/stable/c/0abe35bc48d4ec80424b1f4b3560c0e082cbd5c1
https://git.kernel.org/stable/c/347dcb84a4874b5fb375092c08d8cc4069b94f81
https://git.kernel.org/stable/c/290a6b88e8c19b6636ed1acc733d1458206f7697
https://git.kernel.org/stable/c/ead2ad1d9f045f26fdce3ef1644913b3a6cd38f2
https://git.kernel.org/stable/c/6c920754f62cefc63fccdc38a062c7c3452e2961
https://git.kernel.org/stable/c/46c17ead5b7389e22e7dc9903fd0ba865d05bda2
https://git.kernel.org/stable/c/fce09ea314505a52f2436397608fa0a5d0934fb1

Timeline