Bluetooth: Fix a refcnt underflow problem for hci_conn
authorZiyang Xuan <william.xuanziyang@huawei.com>
Wed, 4 Oct 2023 12:42:24 +0000 (20:42 +0800)
committerLuiz Augusto von Dentz <luiz.von.dentz@intel.com>
Wed, 11 Oct 2023 18:17:08 +0000 (11:17 -0700)
commitc7f59461f5a78994613afc112cdd73688aef9076
treed859e9632885ea1b8d1e5046998ac99acc205395
parenta239110ee8e0b0aafa265f0d54f7a16744855e70
Bluetooth: Fix a refcnt underflow problem for hci_conn

Syzbot reports a warning as follows:

WARNING: CPU: 1 PID: 26946 at net/bluetooth/hci_conn.c:619
hci_conn_timeout+0x122/0x210 net/bluetooth/hci_conn.c:619
...
Call Trace:
 <TASK>
 process_one_work+0x884/0x15c0 kernel/workqueue.c:2630
 process_scheduled_works kernel/workqueue.c:2703 [inline]
 worker_thread+0x8b9/0x1290 kernel/workqueue.c:2784
 kthread+0x33c/0x440 kernel/kthread.c:388
 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:304
 </TASK>

It is because the HCI_EV_SIMPLE_PAIR_COMPLETE event handler drops
hci_conn directly without check Simple Pairing whether be enabled. But
the Simple Pairing process can only be used if both sides have the
support enabled in the host stack.

Add hci_conn_ssp_enabled() for hci_conn in HCI_EV_IO_CAPA_REQUEST and
HCI_EV_SIMPLE_PAIR_COMPLETE event handlers to fix the problem.

Fixes: 0493684ed239 ("[Bluetooth] Disable disconnect timer during Simple Pairing")
Signed-off-by: Ziyang Xuan <william.xuanziyang@huawei.com>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
net/bluetooth/hci_event.c