/*
* 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.gss;
import java.net.InetAddress;
import java.net.UnknownHostException;
import javax.security.auth.login.LoginException;
import org.apache.sshd.server.session.ServerSession;
import org.ietf.jgss.GSSCredential;
import org.ietf.jgss.GSSException;
import org.ietf.jgss.GSSManager;
/**
* Class providing basic GSS authentication services. Can be used as-is, but is often extended to provide environment
* specific implementations.
*
* @author Richard Evans
*/
public class GSSAuthenticator {
// Options:
//
// Service principal name: if unset, use host/hostname
private String servicePrincipalName;
// Location of Kerberos key table; if unset use default
private String keytabFile;
/**
* Overridable method to get GSS manager suitable for current environment.
*
* @return A new manager
*/
public GSSManager getGSSManager() {
return GSSManager.getInstance();
}
/**
* Overridable method to get GSS accept credential suitable for the current environment. The default
* implementation uses a Kerberos key table.
*
* @param mgr The GSS manager
* @return The credential; if the result is {@code null} gssapi authentication fails immediately
* @throws UnknownHostException If the local host name could not be determined
* @throws LoginException If the subject could not be found
* @throws GSSException If the credential could not be obtained
*/
public GSSCredential getGSSCredential(GSSManager mgr) throws UnknownHostException, LoginException, GSSException {
String name = servicePrincipalName;
if (name == null) {
name = "host/" + InetAddress.getLocalHost().getCanonicalHostName();
}
return CredentialHelper.creds(mgr, name, keytabFile);
}
/**
* Validate the user name passed in the initial SSH_MSG_USERAUTH_REQUEST message. This is sort of mandated by RFC 4462, but it
* may be more useful to wait for the GSS negotiation to complete. The default implementation here always succeeds.
*
* @param session The current session
* @param user The user name from the initial request
* @return <code>true</code> if the user is valid, <code>false</code> if invalid
*/
public boolean validateInitialUser(ServerSession session, String user) {
return true;
}
/**
* Validate the source identity obtained from the context after negotiation is complete.
* The default implementation here always succeeds.
*
* @param session The current session
* @param identity The identity from the GSS context
* @return <code>true</code> if the identity is valid, <code>false</code> if invalid
*/
public boolean validateIdentity(ServerSession session, String identity) {
return true;
}
/**
* Set the service principal name to be used. The default is host/hostname.
*
* @param servicePrincipalName The principal name
*/
public void setServicePrincipalName(String servicePrincipalName) {
this.servicePrincipalName = servicePrincipalName;
}
/**
* Set the location of the Kerberos keytab. The default is defined by the JRE.
*
* @param keytabFile The location of the keytab
*/
public void setKeytabFile(String keytabFile) {
this.keytabFile = keytabFile;
}
}