J. Duke | 319a3b9 | 2007-12-01 00:00:00 +0000 | [diff] [blame^] | 1 | /* |
| 2 | * Copyright 1999-2003 Sun Microsystems, Inc. All Rights Reserved. |
| 3 | * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| 4 | * |
| 5 | * This code is free software; you can redistribute it and/or modify it |
| 6 | * under the terms of the GNU General Public License version 2 only, as |
| 7 | * published by the Free Software Foundation. Sun designates this |
| 8 | * particular file as subject to the "Classpath" exception as provided |
| 9 | * by Sun in the LICENSE file that accompanied this code. |
| 10 | * |
| 11 | * This code is distributed in the hope that it will be useful, but WITHOUT |
| 12 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| 13 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| 14 | * version 2 for more details (a copy is included in the LICENSE file that |
| 15 | * accompanied this code). |
| 16 | * |
| 17 | * You should have received a copy of the GNU General Public License version |
| 18 | * 2 along with this work; if not, write to the Free Software Foundation, |
| 19 | * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| 20 | * |
| 21 | * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, |
| 22 | * CA 95054 USA or visit www.sun.com if you need additional information or |
| 23 | * have any questions. |
| 24 | */ |
| 25 | |
| 26 | package javax.security.sasl; |
| 27 | |
| 28 | /** |
| 29 | * Performs SASL authentication as a client. |
| 30 | *<p> |
| 31 | * A protocol library such as one for LDAP gets an instance of this |
| 32 | * class in order to perform authentication defined by a specific SASL |
| 33 | * mechanism. Invoking methods on the <tt>SaslClient</tt> instance |
| 34 | * process challenges and create responses according to the SASL |
| 35 | * mechanism implemented by the <tt>SaslClient</tt>. |
| 36 | * As the authentication proceeds, the instance |
| 37 | * encapsulates the state of a SASL client's authentication exchange. |
| 38 | *<p> |
| 39 | * Here's an example of how an LDAP library might use a <tt>SaslClient</tt>. |
| 40 | * It first gets an instance of a <tt>SaslClient</tt>: |
| 41 | *<blockquote><pre> |
| 42 | * SaslClient sc = Sasl.createSaslClient(mechanisms, |
| 43 | * authorizationId, protocol, serverName, props, callbackHandler); |
| 44 | *</pre></blockquote> |
| 45 | * It can then proceed to use the client for authentication. |
| 46 | * For example, an LDAP library might use the client as follows: |
| 47 | *<blockquote><pre> |
| 48 | * // Get initial response and send to server |
| 49 | * byte[] response = (sc.hasInitialResponse() ? sc.evaluateChallenge(new byte[0]) : |
| 50 | * null); |
| 51 | * LdapResult res = ldap.sendBindRequest(dn, sc.getName(), response); |
| 52 | * while (!sc.isComplete() && |
| 53 | * (res.status == SASL_BIND_IN_PROGRESS || res.status == SUCCESS)) { |
| 54 | * response = sc.evaluateChallenge(res.getBytes()); |
| 55 | * if (res.status == SUCCESS) { |
| 56 | * // we're done; don't expect to send another BIND |
| 57 | * if (response != null) { |
| 58 | * throw new SaslException( |
| 59 | * "Protocol error: attempting to send response after completion"); |
| 60 | * } |
| 61 | * break; |
| 62 | * } |
| 63 | * res = ldap.sendBindRequest(dn, sc.getName(), response); |
| 64 | * } |
| 65 | * if (sc.isComplete() && res.status == SUCCESS) { |
| 66 | * String qop = (String) sc.getNegotiatedProperty(Sasl.QOP); |
| 67 | * if (qop != null |
| 68 | * && (qop.equalsIgnoreCase("auth-int") |
| 69 | * || qop.equalsIgnoreCase("auth-conf"))) { |
| 70 | * |
| 71 | * // Use SaslClient.wrap() and SaslClient.unwrap() for future |
| 72 | * // communication with server |
| 73 | * ldap.in = new SecureInputStream(sc, ldap.in); |
| 74 | * ldap.out = new SecureOutputStream(sc, ldap.out); |
| 75 | * } |
| 76 | * } |
| 77 | *</pre></blockquote> |
| 78 | * |
| 79 | * If the mechanism has an initial response, the library invokes |
| 80 | * <tt>evaluateChallenge()</tt> with an empty |
| 81 | * challenge and to get initial response. |
| 82 | * Protocols such as IMAP4, which do not include an initial response with |
| 83 | * their first authentication command to the server, initiates the |
| 84 | * authentication without first calling <tt>hasInitialResponse()</tt> |
| 85 | * or <tt>evaluateChallenge()</tt>. |
| 86 | * When the server responds to the command, it sends an initial challenge. |
| 87 | * For a SASL mechanism in which the client sends data first, the server should |
| 88 | * have issued a challenge with no data. This will then result in a call |
| 89 | * (on the client) to <tt>evaluateChallenge()</tt> with an empty challenge. |
| 90 | * |
| 91 | * @since 1.5 |
| 92 | * |
| 93 | * @see Sasl |
| 94 | * @see SaslClientFactory |
| 95 | * |
| 96 | * @author Rosanna Lee |
| 97 | * @author Rob Weltman |
| 98 | */ |
| 99 | public abstract interface SaslClient { |
| 100 | |
| 101 | /** |
| 102 | * Returns the IANA-registered mechanism name of this SASL client. |
| 103 | * (e.g. "CRAM-MD5", "GSSAPI"). |
| 104 | * @return A non-null string representing the IANA-registered mechanism name. |
| 105 | */ |
| 106 | public abstract String getMechanismName(); |
| 107 | |
| 108 | /** |
| 109 | * Determines whether this mechanism has an optional initial response. |
| 110 | * If true, caller should call <tt>evaluateChallenge()</tt> with an |
| 111 | * empty array to get the initial response. |
| 112 | * |
| 113 | * @return true if this mechanism has an initial response. |
| 114 | */ |
| 115 | public abstract boolean hasInitialResponse(); |
| 116 | |
| 117 | /** |
| 118 | * Evaluates the challenge data and generates a response. |
| 119 | * If a challenge is received from the server during the authentication |
| 120 | * process, this method is called to prepare an appropriate next |
| 121 | * response to submit to the server. |
| 122 | * |
| 123 | * @param challenge The non-null challenge sent from the server. |
| 124 | * The challenge array may have zero length. |
| 125 | * |
| 126 | * @return The possibly null reponse to send to the server. |
| 127 | * It is null if the challenge accompanied a "SUCCESS" status and the challenge |
| 128 | * only contains data for the client to update its state and no response |
| 129 | * needs to be sent to the server. The response is a zero-length byte |
| 130 | * array if the client is to send a response with no data. |
| 131 | * @exception SaslException If an error occurred while processing |
| 132 | * the challenge or generating a response. |
| 133 | */ |
| 134 | public abstract byte[] evaluateChallenge(byte[] challenge) |
| 135 | throws SaslException; |
| 136 | |
| 137 | /** |
| 138 | * Determines whether the authentication exchange has completed. |
| 139 | * This method may be called at any time, but typically, it |
| 140 | * will not be called until the caller has received indication |
| 141 | * from the server |
| 142 | * (in a protocol-specific manner) that the exchange has completed. |
| 143 | * |
| 144 | * @return true if the authentication exchange has completed; false otherwise. |
| 145 | */ |
| 146 | public abstract boolean isComplete(); |
| 147 | |
| 148 | /** |
| 149 | * Unwraps a byte array received from the server. |
| 150 | * This method can be called only after the authentication exchange has |
| 151 | * completed (i.e., when <tt>isComplete()</tt> returns true) and only if |
| 152 | * the authentication exchange has negotiated integrity and/or privacy |
| 153 | * as the quality of protection; otherwise, an |
| 154 | * <tt>IllegalStateException</tt> is thrown. |
| 155 | *<p> |
| 156 | * <tt>incoming</tt> is the contents of the SASL buffer as defined in RFC 2222 |
| 157 | * without the leading four octet field that represents the length. |
| 158 | * <tt>offset</tt> and <tt>len</tt> specify the portion of <tt>incoming</tt> |
| 159 | * to use. |
| 160 | * |
| 161 | * @param incoming A non-null byte array containing the encoded bytes |
| 162 | * from the server. |
| 163 | * @param offset The starting position at <tt>incoming</tt> of the bytes to use. |
| 164 | * @param len The number of bytes from <tt>incoming</tt> to use. |
| 165 | * @return A non-null byte array containing the decoded bytes. |
| 166 | * @exception SaslException if <tt>incoming</tt> cannot be successfully |
| 167 | * unwrapped. |
| 168 | * @exception IllegalStateException if the authentication exchange has |
| 169 | * not completed, or if the negotiated quality of protection |
| 170 | * has neither integrity nor privacy. |
| 171 | */ |
| 172 | public abstract byte[] unwrap(byte[] incoming, int offset, int len) |
| 173 | throws SaslException; |
| 174 | |
| 175 | /** |
| 176 | * Wraps a byte array to be sent to the server. |
| 177 | * This method can be called only after the authentication exchange has |
| 178 | * completed (i.e., when <tt>isComplete()</tt> returns true) and only if |
| 179 | * the authentication exchange has negotiated integrity and/or privacy |
| 180 | * as the quality of protection; otherwise, an |
| 181 | * <tt>IllegalStateException</tt> is thrown. |
| 182 | *<p> |
| 183 | * The result of this method will make up the contents of the SASL buffer |
| 184 | * as defined in RFC 2222 without the leading four octet field that |
| 185 | * represents the length. |
| 186 | * <tt>offset</tt> and <tt>len</tt> specify the portion of <tt>outgoing</tt> |
| 187 | * to use. |
| 188 | * |
| 189 | * @param outgoing A non-null byte array containing the bytes to encode. |
| 190 | * @param offset The starting position at <tt>outgoing</tt> of the bytes to use. |
| 191 | * @param len The number of bytes from <tt>outgoing</tt> to use. |
| 192 | * @return A non-null byte array containing the encoded bytes. |
| 193 | * @exception SaslException if <tt>outgoing</tt> cannot be successfully |
| 194 | * wrapped. |
| 195 | * @exception IllegalStateException if the authentication exchange has |
| 196 | * not completed, or if the negotiated quality of protection |
| 197 | * has neither integrity nor privacy. |
| 198 | */ |
| 199 | public abstract byte[] wrap(byte[] outgoing, int offset, int len) |
| 200 | throws SaslException; |
| 201 | |
| 202 | /** |
| 203 | * Retrieves the negotiated property. |
| 204 | * This method can be called only after the authentication exchange has |
| 205 | * completed (i.e., when <tt>isComplete()</tt> returns true); otherwise, an |
| 206 | * <tt>IllegalStateException</tt> is thrown. |
| 207 | * |
| 208 | * @param propName The non-null property name. |
| 209 | * @return The value of the negotiated property. If null, the property was |
| 210 | * not negotiated or is not applicable to this mechanism. |
| 211 | * @exception IllegalStateException if this authentication exchange |
| 212 | * has not completed |
| 213 | */ |
| 214 | |
| 215 | public abstract Object getNegotiatedProperty(String propName); |
| 216 | |
| 217 | /** |
| 218 | * Disposes of any system resources or security-sensitive information |
| 219 | * the SaslClient might be using. Invoking this method invalidates |
| 220 | * the SaslClient instance. This method is idempotent. |
| 221 | * @throws SaslException If a problem was encountered while disposing |
| 222 | * the resources. |
| 223 | */ |
| 224 | public abstract void dispose() throws SaslException; |
| 225 | } |