CVE-2023-52468 class: fix use-after-free in class_register()
A use-after-free in the Linux kernel class_register function can cause a crash when lockdep is enabled and a driver fails to register.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2023-52468?
CVE-2023-52468 is a high-severity use after free vulnerability in Linux kernel, published on 25 Feb 2024. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
In the Linux kernel, the following vulnerability has been resolved:
class: fix use-after-free in class_register()
The lock_class_key is still registered and can be found in lock_keys_hash hlist after subsys_private is freed in error handler path.A task who iterate over the lock_keys_hash later may cause use-after-free.So fix that up and unregister the lock_class_key before kfree(cp).
On our platform, a driver fails to kset_register because of creating duplicate filename '/class/xxx'.With Kasan enabled, it prints a invalid-access bug report.
KASAN bug report:
BUG: KASAN: invalid-access in lockdep_register_key+0x19c/0x1bc Write of size 8 at addr 15ffff808b8c0368 by task modprobe/252 Pointer tag: [15], memory tag: [fe]
CPU: 7 PID: 252 Comm: modprobe Tainted: G W 6.6.0-mainline-maybe-dirty #1
Call trace: dump_backtrace+0x1b0/0x1e4 show_stack+0x2c/0x40 dump_stack_lvl+0xac/0xe0 print_report+0x18c/0x4d8 kasan_report+0xe8/0x148 __hwasan_store8_noabort+0x88/0x98 lockdep_register_key+0x19c/0x1bc class_register+0x94/0x1ec init_module+0xbc/0xf48 [rfkill] do_one_initcall+0x17c/0x72c do_init_module+0x19c/0x3f8 ... Memory state around the buggy address: ffffff808b8c0100: 8a 8a 8a 8a 8a 8a 8a 8a 8a 8a 8a 8a 8a 8a 8a 8a ffffff808b8c0200: 8a 8a 8a 8a 8a 8a 8a 8a fe fe fe fe fe fe fe fe >ffffff808b8c0300: fe fe fe fe fe fe fe fe fe fe fe fe fe fe fe fe ^ ffffff808b8c0400: 03 03 03 03 03 03 03 03 03 03 03 03 03 03 03 03
As CONFIG_KASAN_GENERIC is not set, Kasan reports invalid-access not use-after-free here.In this case, modprobe is manipulating the corrupted lock_keys_hash hlish where lock_class_key is already freed before.
It's worth noting that this only can happen if lockdep is enabled, which is not true for normal system.
Weakness: CWE-416
Which versions are affected by CVE-2023-52468?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2023-52468?
Apply the vendor's patch.
Upgrade to the fixed version. These bugs are found with fuzzing and sanitisers and avoided by memory-safe languages. More about Use after free.
Is CVE-2023-52468 being exploited?
There is no known exploitation of CVE-2023-52468 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as BELL-CVE-2023-52468, DEBIAN-CVE-2023-52468, GHSA-p88p-j9px-cq4j, UBUNTU-CVE-2023-52468.