/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing,
* software distributed under the License is distributed on an
* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
* KIND, either express or implied. See the License for the
* specific language governing permissions and limitations
* under the License.
*/
package org.apache.sshd.server.auth.keyboard;
import java.util.List;
import org.apache.sshd.server.session.ServerSession;
/**
* Provides pluggable authentication using the "keyboard-interactive"
* method as specified by <A HREF="https://www.ietf.org/rfc/rfc4256.txt">RFC-4256</A>?
*
* @author <a href="mailto:dev@mina.apache.org">Apache MINA SSHD Project</a>
*/
public interface KeyboardInteractiveAuthenticator {
/**
* An authenticator that rejects any attempt to use it
*/
KeyboardInteractiveAuthenticator NONE = new KeyboardInteractiveAuthenticator() {
@Override
public InteractiveChallenge generateChallenge(ServerSession session, String username, String lang, String subMethods) {
return null;
}
@Override
public boolean authenticate(ServerSession session, String username, List<String> responses) throws Exception {
return false;
}
@Override
public String toString() {
return "NONE";
}
};
/**
* Generates the interactive "challenge" to send to the client
*
* @param session The {@link ServerSession} through which the request was received
* @param username The username
* @param lang The language tag
* @param subMethods Sub-methods hints sent by the client
* @return The {@link InteractiveChallenge} - if {@code null} then authentication
* attempt via "keyboard-interactive" method is rejected
*/
InteractiveChallenge generateChallenge(ServerSession session, String username, String lang, String subMethods);
/**
* Called to authenticate the response to the challenge(s) sent previously
*
* @param session The {@link ServerSession} through which the response was received
* @param username The username
* @param responses The received responses - <B>Note:</B> it is up to the authenticator
* to make sure that the number of responses matches the number of prompts sent in
* the initial challenge. The <U>order</U> of the responses matches the order of the
* prompts sent to the client
* @return {@code true} if responses have been validated
* @throws Exception if bad responses and server should terminate the connection
*/
boolean authenticate(ServerSession session, String username, List<String> responses) throws Exception;
}