Description (CNA)
In the Linux kernel, the following vulnerability has been resolved: Bluetooth: 6lowpan: avoid untracked enable work lowpan_enable_set() allocates a temporary work item and schedules do_enable_set() on system_wq, then returns to debugfs. The debugfs active operation has ended at that point, but the worker still executes module text and manipulates enable_6lowpan and listen_chan. bt_6lowpan_exit() removes the debugfs files and immediately closes and puts listen_chan. It has no pointer to the queued work item, so it cannot cancel or flush it before tearing down the state that the worker uses. The buggy scenario involves two paths, with each column showing the order within that path: debugfs enable write module exit 1. lowpan_enable_set() allocates 1. bt_6lowpan_exit() removes set_enable work the debugfs file 2. schedule_work() queues 2. bt_6lowpan_exit() closes do_enable_set() and puts listen_chan 3. the write operation returns 3. module teardown can continue 4. do_enable_set() later runs against stale state Run the enable state transition synchronously in lowpan_enable_set() instead. The simple debugfs setter can sleep, and this file already handles the 6LoWPAN control write synchronously under the same set_lock. Once the setter returns, debugfs removal covers the whole operation and exit can no longer race with an untracked work item. Validation reproduced this kernel report: BUG: KASAN: slab-use-after-free in do_enable_set+0x113/0x2e0 Workqueue: events do_enable_set [bluetooth_6lowpan] The buggy address belongs to the object at ffff888109cb8000
Affected (CNA)
| Vendor / product | Versions |
|---|---|
| Linux / Linux | affected 90305829635d90a5053ec99a261035b4ce0a2649 before 333a39f134dd0bc614ef6658e9ccd448080443d1; affected 90305829635d90a5053ec99a261035b4ce0a2649 before 9061d0c19e97bb8d0aa235d0a571a5d6d0be7477; affected 90305829635d90a5053ec99a261035b4ce0a2649 before 31cc289d5b179a37be439043306f518376a58187; affected 90305829635d90a5053ec99a261035b4ce0a2649 before feb3fc2c38ed52003142f31e04109719b200c049; affected 90305829635d90a5053ec99a261035b4ce0a2649 before 352a59dc1f4a41314b6f827c17e16af7ca88271a |
| Linux / Linux | affected 3.19; unaffected 0 before 3.19; unaffected 6.6.160 through 6.6.*; unaffected 6.12.114 through 6.12.*; unaffected 6.18.57 through 6.18.*; unaffected 7.1.5 through 7.1.*; unaffected 7.2 through * |
CWE
No CWE identifiers supplied.
References
- https://git.kernel.org/stable/c/333a39f134dd0bc614ef6658e9ccd448080443d1
- https://git.kernel.org/stable/c/9061d0c19e97bb8d0aa235d0a571a5d6d0be7477
- https://git.kernel.org/stable/c/31cc289d5b179a37be439043306f518376a58187
- https://git.kernel.org/stable/c/feb3fc2c38ed52003142f31e04109719b200c049
- https://git.kernel.org/stable/c/352a59dc1f4a41314b6f827c17e16af7ca88271a