Linux vulnerability

What happened

In the Linux kernel, the following vulnerability has been resolved: bluetooth/l2cap: sync sock recv cb and release The problem occurs between the system call to close the sock and hci_rx_work, where the former releases the sock and the latter accesses it without lock protection. CPU0 CPU1 ---- ---- sock_close hci_rx_work l2cap_sock_release hci_acldata_packet l2cap_sock_kill l2cap_recv_frame sk_free l2cap_conless_channel l2cap_sock_recv_cb If hci_rx_work processes the data that needs to be received before the sock is closed, then everything is normal; Otherwise, the work thread may access the released sock when receiving data. Add a chan mutex in the rx callback of the sock to achieve synchronization between the sock release and recv cb. Sock is dead, so set chan data to NULL, avoid others use invalid sock pointer.

Affected versions

Linux: 5b4cedaa14bd1fe3ca1d59c684203a6ae7747faa through before 2243127db6ba20cbef90c6349a2b1000af401d2e (git); 5b4cedaa14bd1fe3ca1d59c684203a6ae7747faa through before 605572e64cd9cebb05ed609d96cff05b50d18cdf (git); 5b4cedaa14bd1fe3ca1d59c684203a6ae7747faa through before b803f30ea23e0968b6c8285c42adf0d862ab2bf6 (git); 5b4cedaa14bd1fe3ca1d59c684203a6ae7747faa through before 3b732449b78183d17178db40be3a4401cf3cd629 (git); 5b4cedaa14bd1fe3ca1d59c684203a6ae7747faa through before 89e856e124f9ae548572c56b1b70c2255705f8fe (git); 3.4 Fixed: See vendor advisory.

Why it matters

Review the vendor advisory and exposure of the affected product to determine operational impact.

Detection & mitigation

• Apply vendor-provided updates or mitigations.
• Review affected product exposure and access logs.