gcc/libjava/classpath/gnu/javax/crypto/sasl/crammd5/CramMD5Server.java

/* CramMD5Server.java --
   Copyright (C) 2003, 2006 Free Software Foundation, Inc.

This file is a part of GNU Classpath.

GNU Classpath is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or (at
your option) any later version.

GNU Classpath 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 for more details.

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Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301
USA

Linking this library statically or dynamically with other modules is
making a combined work based on this library.  Thus, the terms and
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As a special exception, the copyright holders of this library give you
permission to link this library with independent modules to produce an
executable, regardless of the license terms of these independent
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package gnu.javax.crypto.sasl.crammd5;

import gnu.java.security.Registry;
import gnu.java.security.util.Util;
import gnu.javax.crypto.sasl.NoSuchUserException;
import gnu.javax.crypto.sasl.ServerMechanism;

import java.io.IOException;
import java.io.UnsupportedEncodingException;
import java.security.InvalidKeyException;
import java.util.Arrays;
import java.util.HashMap;
import java.util.Map;

import javax.security.sasl.AuthenticationException;
import javax.security.sasl.SaslException;
import javax.security.sasl.SaslServer;

/**
 * The CRAM-MD5 SASL server-side mechanism.
 */
public class CramMD5Server
    extends ServerMechanism
    implements SaslServer
{
  private byte[] msgID;

  public CramMD5Server()
  {
    super(Registry.SASL_CRAM_MD5_MECHANISM);
  }

  protected void initMechanism() throws SaslException
  {
  }

  protected void resetMechanism() throws SaslException
  {
  }

  public byte[] evaluateResponse(final byte[] response) throws SaslException
  {
    if (state == 0)
      {
        msgID = CramMD5Util.createMsgID();
        state++;
        return msgID;
      }
    final String responseStr = new String(response);
    final int index = responseStr.lastIndexOf(" ");
    final String username = responseStr.substring(0, index);
    final byte[] responseDigest;
    try
      {
        responseDigest = responseStr.substring(index + 1).getBytes("UTF-8");
      }
    catch (UnsupportedEncodingException x)
      {
        throw new AuthenticationException("evaluateResponse()", x);
      }
    // Look up the password
    final char[] password = lookupPassword(username);
    // Compute the digest
    byte[] digest;
    try
      {
        digest = CramMD5Util.createHMac(password, msgID);
      }
    catch (InvalidKeyException x)
      {
        throw new AuthenticationException("evaluateResponse()", x);
      }
    try
      {
        digest = Util.toString(digest).toLowerCase().getBytes("UTF-8");
      }
    catch (UnsupportedEncodingException x)
      {
        throw new AuthenticationException("evaluateResponse()", x);
      }
    // Compare the received and computed digests
    if (! Arrays.equals(digest, responseDigest))
      throw new AuthenticationException("Digest mismatch");
    state++;
    return null;
  }

  public boolean isComplete()
  {
    return (state == 2);
  }

  protected String getNegotiatedQOP()
  {
    return Registry.QOP_AUTH;
  }

  private char[] lookupPassword(final String userName) throws SaslException
  {
    try
      {
        if (! authenticator.contains(userName))
          throw new NoSuchUserException(userName);
        final Map userID = new HashMap();
        userID.put(Registry.SASL_USERNAME, userName);
        final Map credentials = authenticator.lookup(userID);
        final String password = (String) credentials.get(Registry.SASL_PASSWORD);
        if (password == null)
          throw new AuthenticationException("lookupPassword()",
                                            new InternalError());
        return password.toCharArray();
      }
    catch (IOException x)
      {
        if (x instanceof SaslException)
          throw (SaslException) x;
        throw new AuthenticationException("lookupPassword()", x);
      }
  }
}