Bluetooth: Fix CID initialization for fixed channels

Fixed channels have the same source and destination CID. Ensure that the
values get properly initialized when receiving incoming connections and
deriving values from the parent socket.
Signed-off-by: NJohan Hedberg <johan.hedberg@intel.com>
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>

net/bluetooth/l2cap_core.c

@@ -1462,8 +1462,6 @@ static void l2cap_le_conn_ready(struct l2cap_conn *conn)
 	if (!chan)
 		goto clean;
 
-	chan->dcid = L2CAP_CID_ATT;
-
 	bacpy(&chan->src, &hcon->src);
 	bacpy(&chan->dst, &hcon->dst);
 	chan->src_type = bdaddr_type(hcon, hcon->src_type);

net/bluetooth/l2cap_sock.c

@@ -1470,6 +1470,11 @@ static void l2cap_sock_init(struct sock *sk, struct sock *parent)
 		chan->tx_credits = pchan->tx_credits;
 		chan->rx_credits = pchan->rx_credits;
 
+		if (chan->chan_type == L2CAP_CHAN_FIXED) {
+			chan->scid = pchan->scid;
+			chan->dcid = pchan->scid;
+		}
+
 		security_sk_clone(parent, sk);
 	} else {
 		switch (sk->sk_type) {