Bluetooth: Fix null pointer dereference in hci_event_packet()

AMP_MGR is getting derefernced in hci_phy_link_complete_evt(), when called
from hci_event_packet() and there is a possibility, that hcon->amp_mgr may
not be found when accessing after initialization of hcon.

- net/bluetooth/hci_event.c:4945
The bug seems to get triggered in this line:

bredr_hcon = hcon->amp_mgr->l2cap_conn->hcon;

Fix it by adding a NULL check for the hcon->amp_mgr before checking the ev-status.

Fixes: d5e911928bd8 ("Bluetooth: AMP: Process Physical Link Complete evt")
Reported-and-tested-by: syzbot+0bef568258653cff272f@syzkaller.appspotmail.com
Link: https://syzkaller.appspot.com/bug?extid=0bef568258653cff272f
Signed-off-by: Anmol Karn <anmol.karan123@gmail.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>

diff --git a/net/bluetooth/hci_event.c b/net/bluetooth/hci_event.c
index f049639..e72982b 100644 (file)
--- a/net/bluetooth/hci_event.c
+++ b/net/bluetooth/hci_event.c
@@ -4941,6 +4941,11 @@ static void hci_phy_link_complete_evt(struct hci_dev *hdev,
                return;
        }
 
+       if (!hcon->amp_mgr) {
+               hci_dev_unlock(hdev);
+               return;
+       }
+
        if (ev->status) {
                hci_conn_del(hcon);
                hci_dev_unlock(hdev);