Bluetooth: Fix memory leak with L2CAP signal channels

The wrong type of L2CAP signalling packets on the wrong type of
either BR/EDR or LE links need to be dropped. When that happens
the packet is dropped, but the memory not freed. So actually
free the memory as well.
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Gustavo Padovan <gustavo.padovan@collabora.co.uk>

net/bluetooth/l2cap_core.c

@@ -5330,7 +5330,7 @@ static inline void l2cap_le_sig_channel(struct l2cap_conn *conn,
 	l2cap_raw_recv(conn, skb);
 
 	if (hcon->type != LE_LINK)
-		return;
+		goto drop;
 
 	while (len >= L2CAP_CMD_HDR_SIZE) {
 		u16 cmd_len;
@@ -5363,6 +5363,7 @@ static inline void l2cap_le_sig_channel(struct l2cap_conn *conn,
 		len  -= cmd_len;
 	}
 
+drop:
 	kfree_skb(skb);
 }
 
@@ -5378,7 +5379,7 @@ static inline void l2cap_sig_channel(struct l2cap_conn *conn,
 	l2cap_raw_recv(conn, skb);
 
 	if (hcon->type != ACL_LINK)
-		return;
+		goto drop;
 
 	while (len >= L2CAP_CMD_HDR_SIZE) {
 		u16 cmd_len;
@@ -5411,6 +5412,7 @@ static inline void l2cap_sig_channel(struct l2cap_conn *conn,
 		len  -= cmd_len;
 	}
 
+drop:
 	kfree_skb(skb);
 }