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40acc1aa3e
commit e2cb6b891ad2b8caa9131e3be70f45243df82a80 upstream.
There is a possible race condition vulnerability between issuing a HCI
command and removing the cont. Specifically, functions hci_req_sync()
and hci_dev_do_close() can race each other like below:
thread-A in hci_req_sync() | thread-B in hci_dev_do_close()
| hci_req_sync_lock(hdev);
test_bit(HCI_UP, &hdev->flags); |
... | test_and_clear_bit(HCI_UP, &hdev->flags)
hci_req_sync_lock(hdev); |
|
In this commit we alter the sequence in function hci_req_sync(). Hence,
the thread-A cannot issue th.
Signed-off-by: Lin Ma <linma@zju.edu.cn>
Cc: Marcel Holtmann <marcel@holtmann.org>
Fixes: 7c6a329e4447 ("[Bluetooth] Fix regression from using default link policy")
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>