CVE-2024-54683

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

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

The product does not properly acquire or release a lock on a resource, leading to unexpected resource state changes and behaviors.

Affected Software

Extended Description

Locking is a type of synchronization behavior that ensures that multiple independently-operating processes or threads do not interfere with each other when accessing the same resource. All processes/threads are expected to follow the same steps for locking. If these steps are not followed precisely - or if no locking is done at all - then another process/thread could modify the shared resource in a way that is not visible or predictable to the original process. This can lead to data or memory corruption, denial of service, etc.

Potential Mitigations

Related Attack Patterns

• https://cwe.mitre.org/data/definitions/25.html
• https://cwe.mitre.org/data/definitions/26.html
• https://cwe.mitre.org/data/definitions/27.html

References

• https://git.kernel.org/stable/c/45fe76573a2557f632e248cc141342233f422b9a
• https://git.kernel.org/stable/c/8c2c8445cda8f59c38dec7dc10509bcb23ae26a0
• https://git.kernel.org/stable/c/f36b01994d68ffc253c8296e2228dfe6e6431c03