Bluetooth: Don't accept ConfigReq if we aren't in the BT_CONFIG state

If such event happens we shall reply with a Command Reject, because we are
not expecting any configure request.
Signed-off-by: NGustavo F. Padovan <padovan@profusion.mobi>
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>

net/bluetooth/l2cap.c

@@ -3124,8 +3124,14 @@ static inline int l2cap_config_req(struct l2cap_conn *conn, struct l2cap_cmd_hdr
 	if (!sk)
 		return -ENOENT;
 
-	if (sk->sk_state == BT_DISCONN)
+	if (sk->sk_state != BT_CONFIG) {
+		struct l2cap_cmd_rej rej;
+
+		rej.reason = cpu_to_le16(0x0002);
+		l2cap_send_cmd(conn, cmd->ident, L2CAP_COMMAND_REJ,
+				sizeof(rej), &rej);
 		goto unlock;
+	}
 
 	/* Reject if config buffer is too small. */
 	len = cmd_len - sizeof(*req);