001/* SaslServer.java 002 Copyright (C) 2003, 2005, Free Software Foundation, Inc. 003 004This file is part of GNU Classpath. 005 006GNU Classpath is free software; you can redistribute it and/or modify 007it under the terms of the GNU General Public License as published by 008the Free Software Foundation; either version 2, or (at your option) 009any later version. 010 011GNU Classpath is distributed in the hope that it will be useful, but 012WITHOUT ANY WARRANTY; without even the implied warranty of 013MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 014General Public License for more details. 015 016You should have received a copy of the GNU General Public License 017along with GNU Classpath; see the file COPYING. If not, write to the 018Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 01902110-1301 USA. 020 021Linking this library statically or dynamically with other modules is 022making a combined work based on this library. Thus, the terms and 023conditions of the GNU General Public License cover the whole 024combination. 025 026As a special exception, the copyright holders of this library give you 027permission to link this library with independent modules to produce an 028executable, regardless of the license terms of these independent 029modules, and to copy and distribute the resulting executable under 030terms of your choice, provided that you also meet, for each linked 031independent module, the terms and conditions of the license of that 032module. An independent module is a module which is not derived from 033or based on this library. If you modify this library, you may extend 034this exception to your version of the library, but you are not 035obligated to do so. If you do not wish to do so, delete this 036exception statement from your version. */ 037 038 039package 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 */ 098public 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}