Java tutorial
/* * Copyright (c) 2000, 2013, Oracle and/or its affiliates. All rights reserved. * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. * * This code is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License version 2 only, as * published by the Free Software Foundation. Oracle designates this * particular file as subject to the "Classpath" exception as provided * by Oracle in the LICENSE file that accompanied this code. * * This code is distributed in the hope that it will be useful, but WITHOUT * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License * version 2 for more details (a copy is included in the LICENSE file that * accompanied this code). * * You should have received a copy of the GNU General Public License version * 2 along with this work; if not, write to the Free Software Foundation, * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. * * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA * or visit www.oracle.com if you need additional information or have any * questions. */ package javax.security.sasl; /** * Performs SASL authentication as a server. *<p> * A server such an LDAP server gets an instance of this * class in order to perform authentication defined by a specific SASL * mechanism. Invoking methods on the {@code SaslServer} instance * generates challenges according to the SASL * mechanism implemented by the {@code SaslServer}. * As the authentication proceeds, the instance * encapsulates the state of a SASL server's authentication exchange. *<p> * Here's an example of how an LDAP server might use a {@code SaslServer}. * It first gets an instance of a {@code SaslServer} for the SASL mechanism * requested by the client: *<blockquote><pre> * SaslServer ss = Sasl.createSaslServer(mechanism, * "ldap", myFQDN, props, callbackHandler); *</pre></blockquote> * It can then proceed to use the server for authentication. * For example, suppose the LDAP server received an LDAP BIND request * containing the name of the SASL mechanism and an (optional) initial * response. It then might use the server as follows: *<blockquote><pre>{@code * while (!ss.isComplete()) { * try { * byte[] challenge = ss.evaluateResponse(response); * if (ss.isComplete()) { * status = ldap.sendBindResponse(mechanism, challenge, SUCCESS); * } else { * status = ldap.sendBindResponse(mechanism, challenge, SASL_BIND_IN_PROGRESS); * response = ldap.readBindRequest(); * } * } catch (SaslException e) { * status = ldap.sendErrorResponse(e); * break; * } * } * if (ss.isComplete() && status == SUCCESS) { * String qop = (String) sc.getNegotiatedProperty(Sasl.QOP); * if (qop != null * && (qop.equalsIgnoreCase("auth-int") * || qop.equalsIgnoreCase("auth-conf"))) { * * // Use SaslServer.wrap() and SaslServer.unwrap() for future * // communication with client * ldap.in = new SecureInputStream(ss, ldap.in); * ldap.out = new SecureOutputStream(ss, ldap.out); * } * } *}</pre></blockquote> * * @since 1.5 * * @see Sasl * @see SaslServerFactory * * @author Rosanna Lee * @author Rob Weltman */ public abstract interface SaslServer { /** * Returns the IANA-registered mechanism name of this SASL server. * (e.g. "CRAM-MD5", "GSSAPI"). * @return A non-null string representing the IANA-registered mechanism name. */ public abstract String getMechanismName(); /** * Evaluates the response data and generates a challenge. * * If a response is received from the client during the authentication * process, this method is called to prepare an appropriate next * challenge to submit to the client. The challenge is null if the * authentication has succeeded and no more challenge data is to be sent * to the client. It is non-null if the authentication must be continued * by sending a challenge to the client, or if the authentication has * succeeded but challenge data needs to be processed by the client. * {@code isComplete()} should be called * after each call to {@code evaluateResponse()},to determine if any further * response is needed from the client. * * @param response The non-null (but possibly empty) response sent * by the client. * * @return The possibly null challenge to send to the client. * It is null if the authentication has succeeded and there is * no more challenge data to be sent to the client. * @exception SaslException If an error occurred while processing * the response or generating a challenge. */ public abstract byte[] evaluateResponse(byte[] response) throws SaslException; /** * Determines whether the authentication exchange has completed. * This method is typically called after each invocation of * {@code evaluateResponse()} to determine whether the * authentication has completed successfully or should be continued. * @return true if the authentication exchange has completed; false otherwise. */ public abstract boolean isComplete(); /** * Reports the authorization ID in effect for the client of this * session. * This method can only be called if isComplete() returns true. * @return The authorization ID of the client. * @exception IllegalStateException if this authentication session has not completed */ public String getAuthorizationID(); /** * Unwraps a byte array received from the client. * This method can be called only after the authentication exchange has * completed (i.e., when {@code isComplete()} returns true) and only if * the authentication exchange has negotiated integrity and/or privacy * as the quality of protection; otherwise, * an {@code IllegalStateException} is thrown. *<p> * {@code incoming} is the contents of the SASL buffer as defined in RFC 2222 * without the leading four octet field that represents the length. * {@code offset} and {@code len} specify the portion of {@code incoming} * to use. * * @param incoming A non-null byte array containing the encoded bytes * from the client. * @param offset The starting position at {@code incoming} of the bytes to use. * @param len The number of bytes from {@code incoming} to use. * @return A non-null byte array containing the decoded bytes. * @exception SaslException if {@code incoming} cannot be successfully * unwrapped. * @exception IllegalStateException if the authentication exchange has * not completed, or if the negotiated quality of protection * has neither integrity nor privacy */ public abstract byte[] unwrap(byte[] incoming, int offset, int len) throws SaslException; /** * Wraps a byte array to be sent to the client. * This method can be called only after the authentication exchange has * completed (i.e., when {@code isComplete()} returns true) and only if * the authentication exchange has negotiated integrity and/or privacy * as the quality of protection; otherwise, a {@code SaslException} is thrown. *<p> * The result of this method * will make up the contents of the SASL buffer as defined in RFC 2222 * without the leading four octet field that represents the length. * {@code offset} and {@code len} specify the portion of {@code outgoing} * to use. * * @param outgoing A non-null byte array containing the bytes to encode. * @param offset The starting position at {@code outgoing} of the bytes to use. * @param len The number of bytes from {@code outgoing} to use. * @return A non-null byte array containing the encoded bytes. * @exception SaslException if {@code outgoing} cannot be successfully * wrapped. * @exception IllegalStateException if the authentication exchange has * not completed, or if the negotiated quality of protection has * neither integrity nor privacy. */ public abstract byte[] wrap(byte[] outgoing, int offset, int len) throws SaslException; /** * Retrieves the negotiated property. * This method can be called only after the authentication exchange has * completed (i.e., when {@code isComplete()} returns true); otherwise, an * {@code IllegalStateException} is thrown. * <p> * The {@link Sasl} class includes several well-known property names * (For example, {@link Sasl#QOP}). A SASL provider can support other * properties which are specific to the vendor and/or a mechanism. * * @param propName the property * @return The value of the negotiated property. If null, the property was * not negotiated or is not applicable to this mechanism. * @exception IllegalStateException if this authentication exchange has not completed */ public abstract Object getNegotiatedProperty(String propName); /** * Disposes of any system resources or security-sensitive information * the SaslServer might be using. Invoking this method invalidates * the SaslServer instance. This method is idempotent. * @throws SaslException If a problem was encountered while disposing * the resources. */ public abstract void dispose() throws SaslException; }