CVE-2022-50339

/// Technical description

In the Linux kernel, the following vulnerability has been resolved:

Bluetooth: avoid hci_dev_test_and_set_flag() in mgmt_init_hdev()

syzbot is again reporting attempt to cancel uninitialized work

at mgmt_index_removed() [1], for setting of HCI_MGMT flag from

mgmt_init_hdev() from hci_mgmt_cmd() from hci_sock_sendmsg() can

race with testing of HCI_MGMT flag from mgmt_index_removed() from

hci_sock_bind() due to lack of serialization via hci_dev_lock().

Since mgmt_init_hdev() is called with mgmt_chan_list_lock held, we can

safely split hci_dev_test_and_set_flag() into hci_dev_test_flag() and

hci_dev_set_flag(). Thus, in order to close this race, set HCI_MGMT flag

after INIT_DELAYED_WORK() completed.

This is a local fix based on mgmt_chan_list_lock. Lack of serialization

via hci_dev_lock() might be causing different race conditions somewhere

else. But a global fix based on hci_dev_lock() should deserve a future

patch.

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References