/*
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* CDDL HEADER START
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*
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* The contents of this file are subject to the terms of the
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* Common Development and Distribution License, Version 1.0 only
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* (the "License"). You may not use this file except in compliance
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* with the License.
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*
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* You can obtain a copy of the license at legal-notices/CDDLv1_0.txt
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* or http://forgerock.org/license/CDDLv1.0.html.
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* See the License for the specific language governing permissions
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* and limitations under the License.
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*
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* When distributing Covered Code, include this CDDL HEADER in each
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* file and include the License file at legal-notices/CDDLv1_0.txt.
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* If applicable, add the following below this CDDL HEADER, with the
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* fields enclosed by brackets "[]" replaced with your own identifying
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* information:
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* Portions Copyright [yyyy] [name of copyright owner]
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*
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* CDDL HEADER END
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*
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*
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* Copyright 2006-2009 Sun Microsystems, Inc.
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* Portions Copyright 2011-2014 ForgeRock AS.
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*/
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package org.opends.server.extensions;
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import java.security.MessageDigest;
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import java.security.SecureRandom;
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import java.text.ParseException;
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import java.util.ArrayList;
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import java.util.Arrays;
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import java.util.List;
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import java.util.concurrent.locks.Lock;
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import org.forgerock.i18n.LocalizableMessage;
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import org.opends.server.admin.server.ConfigurationChangeListener;
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import org.opends.server.admin.std.server.CramMD5SASLMechanismHandlerCfg;
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import org.opends.server.admin.std.server.SASLMechanismHandlerCfg;
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import org.opends.server.api.*;
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import org.opends.server.config.ConfigException;
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import org.opends.server.core.BindOperation;
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import org.opends.server.core.DirectoryServer;
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import org.opends.server.core.PasswordPolicyState;
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import org.forgerock.i18n.slf4j.LocalizedLogger;
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import org.opends.server.types.*;
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import org.forgerock.opendj.ldap.ResultCode;
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import org.forgerock.opendj.ldap.ByteString;
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import static org.opends.messages.ExtensionMessages.*;
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import static org.opends.server.util.ServerConstants.*;
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import static org.opends.server.util.StaticUtils.*;
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/**
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* This class provides an implementation of a SASL mechanism that uses digest
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* authentication via CRAM-MD5. This is a password-based mechanism that does
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* not expose the password itself over the wire but rather uses an MD5 hash that
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* proves the client knows the password. This is similar to the DIGEST-MD5
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* mechanism, and the primary differences are that CRAM-MD5 only obtains random
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* data from the server (whereas DIGEST-MD5 uses random data from both the
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* server and the client), CRAM-MD5 does not allow for an authorization ID in
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* addition to the authentication ID where DIGEST-MD5 does, and CRAM-MD5 does
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* not define any integrity and confidentiality mechanisms where DIGEST-MD5
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* does. This implementation is based on the proposal defined in
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* draft-ietf-sasl-crammd5-05.
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*/
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public class CRAMMD5SASLMechanismHandler
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extends SASLMechanismHandler<CramMD5SASLMechanismHandlerCfg>
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implements ConfigurationChangeListener<
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CramMD5SASLMechanismHandlerCfg>
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{
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private static final LocalizedLogger logger = LocalizedLogger.getLoggerForThisClass();
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// An array filled with the inner pad byte.
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private byte[] iPad;
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// An array filled with the outer pad byte.
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private byte[] oPad;
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// The current configuration for this SASL mechanism handler.
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private CramMD5SASLMechanismHandlerCfg currentConfig;
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// The identity mapper that will be used to map ID strings to user entries.
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private IdentityMapper<?> identityMapper;
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// The message digest engine that will be used to create the MD5 digests.
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private MessageDigest md5Digest;
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// The lock that will be used to provide threadsafe access to the message
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// digest.
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private Object digestLock;
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// The random number generator that we will use to create the server
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// challenge.
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private SecureRandom randomGenerator;
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/**
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* Creates a new instance of this SASL mechanism handler. No initialization
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* should be done in this method, as it should all be performed in the
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* <CODE>initializeSASLMechanismHandler</CODE> method.
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*/
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public CRAMMD5SASLMechanismHandler()
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{
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super();
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}
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/**
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* {@inheritDoc}
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*/
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@Override()
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public void initializeSASLMechanismHandler(
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CramMD5SASLMechanismHandlerCfg configuration)
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throws ConfigException, InitializationException
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{
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configuration.addCramMD5ChangeListener(this);
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currentConfig = configuration;
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// Initialize the variables needed for the MD5 digest creation.
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digestLock = new Object();
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randomGenerator = new SecureRandom();
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try
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{
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md5Digest = MessageDigest.getInstance("MD5");
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}
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catch (Exception e)
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{
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logger.traceException(e);
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LocalizableMessage message =
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ERR_SASLCRAMMD5_CANNOT_GET_MESSAGE_DIGEST.get(getExceptionMessage(e));
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throw new InitializationException(message, e);
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}
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// Create and fill the iPad and oPad arrays.
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iPad = new byte[HMAC_MD5_BLOCK_LENGTH];
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oPad = new byte[HMAC_MD5_BLOCK_LENGTH];
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Arrays.fill(iPad, CRAMMD5_IPAD_BYTE);
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Arrays.fill(oPad, CRAMMD5_OPAD_BYTE);
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// Get the identity mapper that should be used to find users.
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DN identityMapperDN = configuration.getIdentityMapperDN();
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identityMapper = DirectoryServer.getIdentityMapper(identityMapperDN);
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DirectoryServer.registerSASLMechanismHandler(SASL_MECHANISM_CRAM_MD5, this);
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}
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/**
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* {@inheritDoc}
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*/
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@Override()
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public void finalizeSASLMechanismHandler()
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{
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currentConfig.removeCramMD5ChangeListener(this);
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DirectoryServer.deregisterSASLMechanismHandler(SASL_MECHANISM_CRAM_MD5);
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}
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/**
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* {@inheritDoc}
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*/
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@Override()
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public void processSASLBind(BindOperation bindOperation)
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{
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// The CRAM-MD5 bind process uses two stages. See if the client provided
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// any credentials. If not, then we're in the first stage so we'll send the
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// challenge to the client.
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ByteString clientCredentials = bindOperation.getSASLCredentials();
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ClientConnection clientConnection = bindOperation.getClientConnection();
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if (clientCredentials == null)
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{
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// The client didn't provide any credentials, so this is the initial
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// request. Generate some random data to send to the client as the
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// challenge and store it in the client connection so we can verify the
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// credentials provided by the client later.
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byte[] challengeBytes = new byte[16];
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randomGenerator.nextBytes(challengeBytes);
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StringBuilder challengeString = new StringBuilder(18);
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challengeString.append('<');
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for (byte b : challengeBytes)
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{
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challengeString.append(byteToLowerHex(b));
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}
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challengeString.append('>');
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ByteString challenge =
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ByteString.valueOf(challengeString.toString());
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clientConnection.setSASLAuthStateInfo(challenge);
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bindOperation.setServerSASLCredentials(challenge);
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bindOperation.setResultCode(ResultCode.SASL_BIND_IN_PROGRESS);
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return;
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}
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// If we've gotten here, then the client did provide credentials. First,
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// make sure that we have a stored version of the credentials associated
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// with the client connection. If not, then it likely means that the client
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// is trying to pull a fast one on us.
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Object saslStateInfo = clientConnection.getSASLAuthStateInfo();
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if (saslStateInfo == null)
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{
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bindOperation.setResultCode(ResultCode.INVALID_CREDENTIALS);
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LocalizableMessage message = ERR_SASLCRAMMD5_NO_STORED_CHALLENGE.get();
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bindOperation.setAuthFailureReason(message);
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return;
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}
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if (! (saslStateInfo instanceof ByteString))
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{
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bindOperation.setResultCode(ResultCode.INVALID_CREDENTIALS);
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LocalizableMessage message = ERR_SASLCRAMMD5_INVALID_STORED_CHALLENGE.get();
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bindOperation.setAuthFailureReason(message);
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return;
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}
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ByteString challenge = (ByteString) saslStateInfo;
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// Wipe out the stored challenge so it can't be used again.
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clientConnection.setSASLAuthStateInfo(null);
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// Now look at the client credentials and make sure that we can decode them.
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// It should be a username followed by a space and a digest string. Since
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// the username itself may contain spaces but the digest string may not,
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// look for the last space and use it as the delimiter.
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String credString = clientCredentials.toString();
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int spacePos = credString.lastIndexOf(' ');
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if (spacePos < 0)
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{
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bindOperation.setResultCode(ResultCode.INVALID_CREDENTIALS);
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LocalizableMessage message = ERR_SASLCRAMMD5_NO_SPACE_IN_CREDENTIALS.get();
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bindOperation.setAuthFailureReason(message);
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return;
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}
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String userName = credString.substring(0, spacePos);
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String digest = credString.substring(spacePos+1);
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// Look at the digest portion of the provided credentials. It must have a
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// length of exactly 32 bytes and be comprised only of hex characters.
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if (digest.length() != (2*MD5_DIGEST_LENGTH))
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{
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bindOperation.setResultCode(ResultCode.INVALID_CREDENTIALS);
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LocalizableMessage message = ERR_SASLCRAMMD5_INVALID_DIGEST_LENGTH.get(
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digest.length(),
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(2*MD5_DIGEST_LENGTH));
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bindOperation.setAuthFailureReason(message);
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return;
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}
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byte[] digestBytes;
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try
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{
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digestBytes = hexStringToByteArray(digest);
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}
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catch (ParseException pe)
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{
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logger.traceException(pe);
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bindOperation.setResultCode(ResultCode.INVALID_CREDENTIALS);
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LocalizableMessage message = ERR_SASLCRAMMD5_INVALID_DIGEST_CONTENT.get(
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pe.getMessage());
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bindOperation.setAuthFailureReason(message);
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return;
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}
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// Get the user entry for the authentication ID. Allow for an
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// authentication ID that is just a username (as per the CRAM-MD5 spec), but
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// also allow a value in the authzid form specified in RFC 2829.
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Entry userEntry = null;
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String lowerUserName = toLowerCase(userName);
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if (lowerUserName.startsWith("dn:"))
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{
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// Try to decode the user DN and retrieve the corresponding entry.
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DN userDN;
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try
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{
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userDN = DN.valueOf(userName.substring(3));
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}
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catch (DirectoryException de)
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{
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logger.traceException(de);
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bindOperation.setResultCode(ResultCode.INVALID_CREDENTIALS);
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LocalizableMessage message = ERR_SASLCRAMMD5_CANNOT_DECODE_USERNAME_AS_DN.get(
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userName, de.getMessageObject());
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bindOperation.setAuthFailureReason(message);
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return;
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}
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if (userDN.isRootDN())
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{
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bindOperation.setResultCode(ResultCode.INVALID_CREDENTIALS);
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LocalizableMessage message = ERR_SASLCRAMMD5_USERNAME_IS_NULL_DN.get();
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bindOperation.setAuthFailureReason(message);
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return;
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}
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DN rootDN = DirectoryServer.getActualRootBindDN(userDN);
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if (rootDN != null)
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{
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userDN = rootDN;
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}
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// Acquire a read lock on the user entry. If this fails, then so will the
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// authentication.
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final Lock readLock = LockManager.lockRead(userDN);
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if (readLock == null)
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{
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bindOperation.setResultCode(ResultCode.BUSY);
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bindOperation.setAuthFailureReason(INFO_SASLCRAMMD5_CANNOT_LOCK_ENTRY.get(userDN));
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return;
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}
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try
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{
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userEntry = DirectoryServer.getEntry(userDN);
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}
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catch (DirectoryException de)
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{
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logger.traceException(de);
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bindOperation.setResultCode(ResultCode.INVALID_CREDENTIALS);
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LocalizableMessage message = ERR_SASLCRAMMD5_CANNOT_GET_ENTRY_BY_DN.get(userDN, de.getMessageObject());
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bindOperation.setAuthFailureReason(message);
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return;
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}
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finally
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{
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LockManager.unlock(userDN, readLock);
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}
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}
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else
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{
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// Use the identity mapper to resolve the username to an entry.
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if (lowerUserName.startsWith("u:"))
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{
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userName = userName.substring(2);
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}
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try
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{
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userEntry = identityMapper.getEntryForID(userName);
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}
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catch (DirectoryException de)
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{
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logger.traceException(de);
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bindOperation.setResultCode(ResultCode.INVALID_CREDENTIALS);
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LocalizableMessage message = ERR_SASLCRAMMD5_CANNOT_MAP_USERNAME.get(userName, de.getMessageObject());
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bindOperation.setAuthFailureReason(message);
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return;
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}
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}
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// At this point, we should have a user entry. If we don't then fail.
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if (userEntry == null)
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{
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bindOperation.setResultCode(ResultCode.INVALID_CREDENTIALS);
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LocalizableMessage message = ERR_SASLCRAMMD5_NO_MATCHING_ENTRIES.get(userName);
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bindOperation.setAuthFailureReason(message);
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return;
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}
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else
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{
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bindOperation.setSASLAuthUserEntry(userEntry);
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}
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// Get the clear-text passwords from the user entry, if there are any.
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List<ByteString> clearPasswords;
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try
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{
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AuthenticationPolicyState authState = AuthenticationPolicyState.forUser(
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userEntry, false);
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if (!authState.isPasswordPolicy())
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{
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bindOperation.setResultCode(ResultCode.INAPPROPRIATE_AUTHENTICATION);
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LocalizableMessage message = ERR_SASL_ACCOUNT_NOT_LOCAL
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.get(SASL_MECHANISM_CRAM_MD5, userEntry.getName());
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bindOperation.setAuthFailureReason(message);
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return;
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}
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PasswordPolicyState pwPolicyState = (PasswordPolicyState) authState;
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clearPasswords = pwPolicyState.getClearPasswords();
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if ((clearPasswords == null) || clearPasswords.isEmpty())
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{
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bindOperation.setResultCode(ResultCode.INVALID_CREDENTIALS);
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LocalizableMessage message = ERR_SASLCRAMMD5_NO_REVERSIBLE_PASSWORDS.get(userEntry.getName());
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bindOperation.setAuthFailureReason(message);
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return;
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}
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}
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catch (Exception e)
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{
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bindOperation.setResultCode(ResultCode.INVALID_CREDENTIALS);
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LocalizableMessage message = ERR_SASLCRAMMD5_CANNOT_GET_REVERSIBLE_PASSWORDS.get( userEntry.getName(), e);
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bindOperation.setAuthFailureReason(message);
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return;
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}
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// Iterate through the clear-text values and see if any of them can be used
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// in conjunction with the challenge to construct the provided digest.
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boolean matchFound = false;
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for (ByteString clearPassword : clearPasswords)
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{
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byte[] generatedDigest = generateDigest(clearPassword, challenge);
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if (Arrays.equals(digestBytes, generatedDigest))
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{
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matchFound = true;
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break;
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}
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}
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if (! matchFound)
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{
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bindOperation.setResultCode(ResultCode.INVALID_CREDENTIALS);
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LocalizableMessage message = ERR_SASLCRAMMD5_INVALID_PASSWORD.get();
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bindOperation.setAuthFailureReason(message);
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return;
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}
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// If we've gotten here, then the authentication was successful.
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bindOperation.setResultCode(ResultCode.SUCCESS);
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AuthenticationInfo authInfo = new AuthenticationInfo(userEntry,
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SASL_MECHANISM_CRAM_MD5, DirectoryServer.isRootDN(userEntry.getName()));
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bindOperation.setAuthenticationInfo(authInfo);
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}
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/**
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* Generates the appropriate HMAC-MD5 digest for a CRAM-MD5 authentication
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* with the given information.
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*
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* @param password The clear-text password to use when generating the
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* digest.
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* @param challenge The server-supplied challenge to use when generating the
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* digest.
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*
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* @return The generated HMAC-MD5 digest for CRAM-MD5 authentication.
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*/
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private byte[] generateDigest(ByteString password, ByteString challenge)
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{
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// Get the byte arrays backing the password and challenge.
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byte[] p = password.toByteArray();
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byte[] c = challenge.toByteArray();
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// Grab a lock to protect the MD5 digest generation.
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synchronized (digestLock)
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{
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// If the password is longer than the HMAC-MD5 block length, then use an
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// MD5 digest of the password rather than the password itself.
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if (p.length > HMAC_MD5_BLOCK_LENGTH)
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{
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p = md5Digest.digest(p);
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}
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// Create byte arrays with data needed for the hash generation.
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byte[] iPadAndData = new byte[HMAC_MD5_BLOCK_LENGTH + c.length];
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System.arraycopy(iPad, 0, iPadAndData, 0, HMAC_MD5_BLOCK_LENGTH);
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System.arraycopy(c, 0, iPadAndData, HMAC_MD5_BLOCK_LENGTH, c.length);
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byte[] oPadAndHash = new byte[HMAC_MD5_BLOCK_LENGTH + MD5_DIGEST_LENGTH];
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System.arraycopy(oPad, 0, oPadAndHash, 0, HMAC_MD5_BLOCK_LENGTH);
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// Iterate through the bytes in the key and XOR them with the iPad and
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// oPad as appropriate.
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for (int i=0; i < p.length; i++)
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{
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iPadAndData[i] ^= p[i];
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oPadAndHash[i] ^= p[i];
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}
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// Copy an MD5 digest of the iPad-XORed key and the data into the array to
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// be hashed.
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System.arraycopy(md5Digest.digest(iPadAndData), 0, oPadAndHash,
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HMAC_MD5_BLOCK_LENGTH, MD5_DIGEST_LENGTH);
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// Return an MD5 digest of the resulting array.
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return md5Digest.digest(oPadAndHash);
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}
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}
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/**
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* {@inheritDoc}
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*/
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@Override()
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public boolean isPasswordBased(String mechanism)
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{
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// This is a password-based mechanism.
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return true;
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}
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/**
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* {@inheritDoc}
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*/
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@Override()
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public boolean isSecure(String mechanism)
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{
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// This may be considered a secure mechanism.
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return true;
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}
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/**
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* {@inheritDoc}
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*/
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@Override()
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public boolean isConfigurationAcceptable(
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SASLMechanismHandlerCfg configuration,
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List<LocalizableMessage> unacceptableReasons)
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{
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CramMD5SASLMechanismHandlerCfg config =
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(CramMD5SASLMechanismHandlerCfg) configuration;
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return isConfigurationChangeAcceptable(config, unacceptableReasons);
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}
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/**
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* {@inheritDoc}
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*/
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@Override
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public boolean isConfigurationChangeAcceptable(
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CramMD5SASLMechanismHandlerCfg configuration,
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List<LocalizableMessage> unacceptableReasons)
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{
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return true;
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}
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/**
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* {@inheritDoc}
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*/
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@Override
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public ConfigChangeResult applyConfigurationChange(
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CramMD5SASLMechanismHandlerCfg configuration)
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{
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ResultCode resultCode = ResultCode.SUCCESS;
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boolean adminActionRequired = false;
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ArrayList<LocalizableMessage> messages = new ArrayList<LocalizableMessage>();
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DN identityMapperDN = configuration.getIdentityMapperDN();
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identityMapper = DirectoryServer.getIdentityMapper(identityMapperDN);
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currentConfig = configuration;
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return new ConfigChangeResult(resultCode, adminActionRequired, messages);
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}
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}
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