CVE-2024-54683 Information
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->active48)++++-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 estme\n| iptables -D INPUT -i foo -j IDLETIMER –timeout 10 –label estme\n| 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.
Reference
https://git.kernel.org/stable/c/45fe76573a2557f632e248cc141342233f422b9a https://git.kernel.org/stable/c/8c2c8445cda8f59c38dec7dc10509bcb23ae26a0 https://git.kernel.org/stable/c/f36b01994d68ffc253c8296e2228dfe6e6431c03
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