CVE-2024-42232 libceph: fix race between delayed_work() and ceph_monc_stop()
A race condition in the Linux kernel's libceph module allows a use-after-free, potentially enabling local attackers to execute code or escalate privileges.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2024-42232?
CVE-2024-42232 is a critical use after free vulnerability in Linux kernel, published on 7 Aug 2024. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
In the Linux kernel, the following vulnerability has been resolved:
libceph: fix race between delayed_work() and ceph_monc_stop()
The way the delayed work is handled in ceph_monc_stop() is prone to races with mon_fault() and possibly also finish_hunting(). Both of these can requeue the delayed work which wouldn't be canceled by any of the following code in case that happens after cancel_delayed_work_sync() runs -- __close_session() doesn't mess with the delayed work in order to avoid interfering with the hunting interval logic. This part was missed in commit b5d91704f53e ("libceph: behave in mon_fault() if cur_mon < 0") and use-after-free can still ensue on monc and objects that hang off of it, with monc->auth and monc->monmap being particularly susceptible to quickly being reused.
To fix this:
- clear monc->cur_mon and monc->hunting as part of closing the session in ceph_monc_stop() - bail from delayed_work() if monc->cur_mon is cleared, similar to how it's done in mon_fault() and finish_hunting() (based on monc->hunting) - call cancel_delayed_work_sync() after the session is closed
Weakness: CWE-416
Which versions are affected by CVE-2024-42232?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2024-42232?
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-2024-42232 being exploited?
There is no known exploitation of CVE-2024-42232 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as AZL-47561, AZL-47624, BELL-CVE-2024-42232, DEBIAN-CVE-2024-42232, GHSA-5vqw-wppf-x433, UBUNTU-CVE-2024-42232.