001 /* SaslServer.java
002 Copyright (C) 2003, 2005, Free Software Foundation, Inc.
003
004 This file is part of GNU Classpath.
005
006 GNU Classpath is free software; you can redistribute it and/or modify
007 it under the terms of the GNU General Public License as published by
008 the Free Software Foundation; either version 2, or (at your option)
009 any later version.
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014 General Public License for more details.
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019 02110-1301 USA.
020
021 Linking this library statically or dynamically with other modules is
022 making a combined work based on this library. Thus, the terms and
023 conditions of the GNU General Public License cover the whole
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025
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027 permission to link this library with independent modules to produce an
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036 exception statement from your version. */
037
038
039 package javax.security.sasl;
040
041 /**
042 * <p>Performs SASL authentication as a server.</p>
043 *
044 * <p>A server such as an LDAP server gets an instance of this class in order to
045 * perform authentication defined by a specific SASL mechanism. Invoking methods
046 * on the <code>SaslServer</code> instance generates challenges corresponding to
047 * the SASL mechanism implemented by the <code>SaslServer</code> instance. As
048 * the authentication proceeds, the instance encapsulates the state of a SASL
049 * server's authentication exchange.</p>
050 *
051 * <p>Here's an example of how an LDAP server might use a <code>SaslServer</code>
052 * instance. It first gets an instance of a <code>SaslServer</code> for the SASL
053 * mechanism requested by the client:</p>
054 *
055 * <pre>
056 *SaslServer ss =
057 * Sasl.createSaslServer(mechanism, "ldap", myFQDN, props, callbackHandler);
058 * </pre>
059 *
060 * <p>It can then proceed to use the server for authentication. For example,
061 * suppose the LDAP server received an LDAP BIND request containing the name of
062 * the SASL mechanism and an (optional) initial response. It then might use the
063 * server as follows:</p>
064 *
065 * <pre>
066 *while (!ss.isComplete()) {
067 * try {
068 * byte[] challenge = ss.evaluateResponse(response);
069 * if (ss.isComplete()) {
070 * status = ldap.sendBindResponse(mechanism, challenge, SUCCESS);
071 * } else {
072 * status = ldap.sendBindResponse(mechanism, challenge, SASL_BIND_IN_PROGRESS);
073 * response = ldap.readBindRequest();
074 * }
075 * } catch (SaslException x) {
076 * status = ldap.sendErrorResponse(x);
077 * break;
078 * }
079 *}
080 *if (ss.isComplete() && (status == SUCCESS)) {
081 * String qop = (String) sc.getNegotiatedProperty(Sasl.QOP);
082 * if (qop != null
083 * && (qop.equalsIgnoreCase("auth-int")
084 * || qop.equalsIgnoreCase("auth-conf"))) {
085 * // Use SaslServer.wrap() and SaslServer.unwrap() for future
086 * // communication with client
087 * ldap.in = new SecureInputStream(ss, ldap.in);
088 * ldap.out = new SecureOutputStream(ss, ldap.out);
089 * }
090 *}
091 * </pre>
092 *
093 * @see Sasl
094 * @see SaslServerFactory
095 *
096 * @since 1.5
097 */
098 public interface SaslServer
099 {
100
101 /**
102 * Returns the IANA-registered mechanism name of this SASL server (e.g.
103 * "CRAM-MD5", "GSSAPI").
104 *
105 * @return a non-null string representing the IANA-registered mechanism name.
106 */
107 String getMechanismName();
108
109 /**
110 * Evaluates the response data and generates a challenge. If a response is
111 * received from the client during the authentication process, this method is
112 * called to prepare an appropriate next challenge to submit to the client.
113 * The challenge is <code>null</code> if the authentication has succeeded and
114 * no more challenge data is to be sent to the client. It is non-null if the
115 * authentication must be continued by sending a challenge to the client, or
116 * if the authentication has succeeded but challenge data needs to be
117 * processed by the client. {@link #isComplete()} should be called after each
118 * call to <code>evaluateResponse()</code>,to determine if any further
119 * response is needed from the client.
120 *
121 * @param response the non-null (but possibly empty) response sent by the
122 * client.
123 * @return the possibly <code>null</code> challenge to send to the client.
124 * It is <code>null</code> if the authentication has succeeded and there is
125 * no more challenge data to be sent to the client.
126 * @throws SaslException if an error occurred while processing the response
127 * or generating a challenge.
128 */
129 byte[] evaluateResponse(byte[] response) throws SaslException;
130
131 /**
132 * Determines if the authentication exchange has completed. This method is
133 * typically called after each invocation of {@link #evaluateResponse(byte[])}
134 * to determine whether the authentication has completed successfully or
135 * should be continued.
136 *
137 * @return <code>true</code> if the authentication exchange has completed;
138 * <code>false</code> otherwise.
139 */
140 boolean isComplete();
141
142 /**
143 * Reports the authorization ID in effect for the client of this session This
144 * method can only be called if {@link #isComplete()} returns <code>true</code>.
145 *
146 * @return the authorization ID of the client.
147 * @throws IllegalStateException if this authentication session has not
148 * completed.
149 */
150 String getAuthorizationID();
151
152 /**
153 * <p>Unwraps a byte array received from the client. This method can be called
154 * only after the authentication exchange has completed (i.e., when
155 * {@link #isComplete()} returns <code>true</code>) and only if the
156 * authentication exchange has negotiated integrity and/or privacy as the
157 * quality of protection; otherwise, an {@link IllegalStateException} is
158 * thrown.</p>
159 *
160 * <p><code>incoming</code> is the contents of the SASL buffer as defined in
161 * RFC 2222 without the leading four octet field that represents the length.
162 * <code>offset</code> and <code>len</code> specify the portion of incoming
163 * to use.</p>
164 *
165 * @param incoming a non-null byte array containing the encoded bytes from
166 * the client.
167 * @param offset the starting position at <code>incoming</code> of the bytes
168 * to use.
169 * @param len the number of bytes from <code>incoming</code> to use.
170 * @return a non-null byte array containing the decoded bytes.
171 * @throws SaslException if <code>incoming</code> cannot be successfully
172 * unwrapped.
173 * @throws IllegalStateException if the authentication exchange has not
174 * completed, or if the negotiated quality of protection has neither
175 * integrity nor privacy.
176 */
177 byte[] unwrap(byte[] incoming, int offset, int len) throws SaslException;
178
179 /**
180 * <p>Wraps a byte array to be sent to the client. This method can be called
181 * only after the authentication exchange has completed (i.e., when
182 * {@link #isComplete()} returns <code>true</code>) and only if the
183 * authentication exchange has negotiated integrity and/or privacy as the
184 * quality of protection; otherwise, an {@link IllegalStateException} is
185 * thrown.</p>
186 *
187 * <p>The result of this method will make up the contents of the SASL buffer
188 * as defined in RFC 2222 without the leading four octet field that
189 * represents the length. <code>offset</code> and <code>len</code> specify
190 * the portion of <code>outgoing</code> to use.
191 *
192 * @param outgoing a non-null byte array containing the bytes to encode.
193 * @param offset the starting position at <code>outgoing</code> of the bytes
194 * to use.
195 * @param len the number of bytes from <code>outgoing</code> to use.
196 * @return a non-null byte array containing the encoded bytes.
197 * @throws SaslException if <code>outgoing</code> cannot be successfully
198 * wrapped.
199 * @throws IllegalStateException if the authentication exchange has not
200 * completed, or if the negotiated quality of protection has neither
201 * integrity nor privacy.
202 */
203 byte[] wrap(byte[] outgoing, int offset, int len) throws SaslException;
204
205 /**
206 * Retrieves the negotiated property. This method can be called only after
207 * the authentication exchange has completed (i.e., when
208 * {@link #isComplete()} returns <code>true</code>); otherwise, an
209 * {@link IllegalStateException} is thrown.
210 *
211 * @return the value of the negotiated property. If <code>null</code>, the
212 * property was not negotiated or is not applicable to this mechanism.
213 * @throws IllegalStateException if this authentication exchange has not
214 * completed.
215 */
216 Object getNegotiatedProperty(String propName);
217
218 /**
219 * Disposes of any system resources or security-sensitive information the
220 * <code>SaslServer</code> might be using. Invoking this method invalidates
221 * the <code>SaslServer</code> instance. This method is idempotent.
222 *
223 * @throws SaslException if a problem was encountered while disposing of the
224 * resources.
225 */
226 void dispose() throws SaslException;
227 }