Description (CNA)
In the Linux kernel, the following vulnerability has been resolved: bridge: cfm: Fix race condition in peer_mep deletion When a peer MEP is being deleted, cancel_delayed_work_sync() is called on ccm_rx_dwork before freeing. However, br_cfm_frame_rx() runs in softirq context under rcu_read_lock (without RTNL) and can re-schedule ccm_rx_dwork via ccm_rx_timer_start() between cancel_delayed_work_sync() returning and kfree_rcu() being called. The following is a simple race scenario: cpu0 cpu1 mep_delete_implementation() cancel_delayed_work_sync(ccm_rx_dwork); br_cfm_frame_rx() // peer_mep still in hlist if (peer_mep->ccm_defect) ccm_rx_timer_start() queue_delayed_work(ccm_rx_dwork) hlist_del_rcu(&peer_mep->head); kfree_rcu(peer_mep, rcu); ccm_rx_work_expired() // on freed peer_mep To prevent this, cancel_delayed_work_sync() is replaced with disable_delayed_work_sync() in both peer MEP deletion paths, so that subsequent queue_delayed_work() calls from br_cfm_frame_rx() are silently rejected. The cc_peer_disable() helper retains cancel_delayed_work_sync() because it is also used for the CC enable/disable toggle path where the work must remain re-schedulable.
Affected (CNA)
| Vendor / product | Versions |
|---|---|
| Linux / Linux | affected dc32cbb3dbd7da38c700d6e0fc6354df24920525 before e89dbd2736a45f0507949af4748cbbf3ff793146; affected dc32cbb3dbd7da38c700d6e0fc6354df24920525 before d8f35767bacb3c7769d470a41cf161e3f3c07e70; affected dc32cbb3dbd7da38c700d6e0fc6354df24920525 before 1fd81151f65927fd9edb8ecd12ad45527dbbe5ab; affected dc32cbb3dbd7da38c700d6e0fc6354df24920525 before 3715a00855316066cdda69d43648336367422127 |
| Linux / Linux | affected 5.11; unaffected 0 before 5.11; unaffected 6.12.78 through 6.12.*; unaffected 6.18.20 through 6.18.*; unaffected 6.19.10 through 6.19.*; unaffected 7.0 through * |
CWE
No CWE identifiers supplied.