CVE-2024-54683 netfilter: IDLETIMER: Fix for possible ABBA deadlock
A race condition in the Linux kernel netfilter IDLETIMER module can cause an ABBA deadlock, leading to a denial of service.
- 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-2024-54683?
CVE-2024-54683 is a medium-severity vulnerability in Linux kernel, published on 11 Jan 2025. 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:
netfilter: IDLETIMER: Fix for possible ABBA deadlock
Deletion of the last rule referencing a given idletimer may happen at the same time as a read of its file in sysfs:
| ====================================================== | WARNING: possible circular locking dependency detected | 6.12.0-rc7-01692-g5e9a28f41134-dirty #594 Not tainted | ------------------------------------------------------ | iptables/3303 is trying to acquire lock: | ffff8881057e04b8 (kn->active#48){++++}-{0:0}, at: __kernfs_remove+0x20 | | but task is already holding lock: | ffffffffa0249068 (list_mutex){+.+.}-{3:3}, at: idletimer_tg_destroy_v] | | which lock already depends on the new lock.
A simple reproducer is:
| #!/bin/bash | | while true; do | iptables -A INPUT -i foo -j IDLETIMER --timeout 10 --label "testme" | iptables -D INPUT -i foo -j IDLETIMER --timeout 10 --label "testme" | done & | while true; do | cat /sys/class/xt_idletimer/timers/testme >/dev/null | done
Avoid this by freeing list_mutex right after deleting the element from the list, then continuing with the teardown.
Weakness: CWE-667
Which versions are affected by CVE-2024-54683?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2024-54683?
Apply the vendor's patch.
Is CVE-2024-54683 being exploited?
There is no known exploitation of CVE-2024-54683 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as AZL-55751, AZL-55771, BELL-CVE-2024-54683, DEBIAN-CVE-2024-54683, GHSA-4qcv-j3wr-hw24, ROOT-OS-DEBIAN-11-CVE-2024-54683 and 3 more.