crypto/sasl/ClientMechanism.java

/* ClientMechanism.java --
   Copyright (C) 2003, 2005, 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
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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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terms of your choice, provided that you also meet, for each linked
independent module, the terms and conditions of the license of that
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or based on this library.  If you modify this library, you may extend
this exception to your version of the library, but you are not
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exception statement from your version.  */


package gnu.javax.crypto.sasl;

import gnu.java.security.Registry;

import java.util.HashMap;
import java.util.Map;

import javax.security.auth.callback.CallbackHandler;
import javax.security.sasl.Sasl;
import javax.security.sasl.SaslClient;
import javax.security.sasl.SaslException;

/**
 * A base class to facilitate implementing SASL client-side mechanisms.
 */
public abstract class ClientMechanism
    implements SaslClient
{
  /** Name of this mechanism. */
  protected String mechanism;
  /** The authorisation identity. */
  protected String authorizationID;
  /** Name of protocol using this mechanism. */
  protected String protocol;
  /** Name of server to authenticate to. */
  protected String serverName;
  /** Properties of qualities desired for this mechanism. */
  protected Map properties;
  /** Callback handler to use with this mechanism instance. */
  protected CallbackHandler handler;
  /** Channel binding data to use with this mechanism instance. */
  protected byte[] channelBinding;
  /** Whether authentication phase is completed (true) or not (false). */
  protected boolean complete = false;
  /** The state of the authentication automaton. */
  protected int state = -1;

  protected ClientMechanism(final String mechanism)
  {
    super();

    this.mechanism = mechanism;
    this.state = -1;
  }

  protected abstract void initMechanism() throws SaslException;

  protected abstract void resetMechanism() throws SaslException;

  public abstract byte[] evaluateChallenge(byte[] challenge)
      throws SaslException;

  public abstract boolean hasInitialResponse();

  public boolean isComplete()
  {
    return complete;
  }

  public byte[] unwrap(final byte[] incoming, final int offset, final int len)
      throws SaslException
  {
    if (! isComplete())
      throw new IllegalMechanismStateException();
    return this.engineUnwrap(incoming, offset, len);
  }

  public byte[] wrap(final byte[] outgoing, final int offset, final int len)
      throws SaslException
  {
    if (! isComplete())
      throw new IllegalMechanismStateException();
    return this.engineWrap(outgoing, offset, len);
  }

  public String getMechanismName()
  {
    return mechanism;
  }

  public Object getNegotiatedProperty(final String propName)
  {
    if (! isComplete())
      throw new IllegalStateException();
    if (Sasl.QOP.equals(propName))
      return getNegotiatedQOP();
    if (Sasl.STRENGTH.equals(propName))
      return getNegotiatedStrength();
    if (Sasl.SERVER_AUTH.equals(propName))
      return getNegotiatedServerAuth();
    if (Sasl.MAX_BUFFER.equals(propName))
      return getNegotiatedMaxBuffer();
    if (Sasl.RAW_SEND_SIZE.equals(propName))
      return getNegotiatedRawSendSize();
    if (Sasl.POLICY_NOPLAINTEXT.equals(propName))
      return getNegotiatedPolicyNoPlainText();
    if (Sasl.POLICY_NOACTIVE.equals(propName))
      return getNegotiatedPolicyNoActive();
    if (Sasl.POLICY_NODICTIONARY.equals(propName))
      return getNegotiatedPolicyNoDictionary();
    if (Sasl.POLICY_NOANONYMOUS.equals(propName))
      return getNegotiatedPolicyNoAnonymous();
    if (Sasl.POLICY_FORWARD_SECRECY.equals(propName))
      return getNegotiatedPolicyForwardSecrecy();
    if (Sasl.POLICY_PASS_CREDENTIALS.equals(propName))
      return getNegotiatedPolicyPassCredentials();
    if (Sasl.REUSE.equals(propName))
      return getReuse();
    return null;
  }

  public void dispose() throws SaslException
  {
  }

  public String getAuthorizationID()
  {
    return authorizationID;
  }

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

  protected String getNegotiatedStrength()
  {
    return Registry.STRENGTH_LOW;
  }

  protected String getNegotiatedServerAuth()
  {
    return Registry.SERVER_AUTH_FALSE;
  }

  protected String getNegotiatedMaxBuffer()
  {
    return null;
  }

  protected String getNegotiatedRawSendSize()
  {
    return String.valueOf(Registry.SASL_BUFFER_MAX_LIMIT);
  }

  protected String getNegotiatedPolicyNoPlainText()
  {
    return null;
  }

  protected String getNegotiatedPolicyNoActive()
  {
    return null;
  }

  protected String getNegotiatedPolicyNoDictionary()
  {
    return null;
  }

  protected String getNegotiatedPolicyNoAnonymous()
  {
    return null;
  }

  protected String getNegotiatedPolicyForwardSecrecy()
  {
    return null;
  }

  protected String getNegotiatedPolicyPassCredentials()
  {
    return null;
  }

  protected String getReuse()
  {
    return Registry.REUSE_FALSE;
  }

  protected byte[] engineUnwrap(final byte[] incoming, final int offset,
                                final int len) throws SaslException
  {
    final byte[] result = new byte[len];
    System.arraycopy(incoming, offset, result, 0, len);
    return result;
  }

  protected byte[] engineWrap(final byte[] outgoing, final int offset,
                              final int len) throws SaslException
  {
    final byte[] result = new byte[len];
    System.arraycopy(outgoing, offset, result, 0, len);
    return result;
  }

  /**
   * Initialises the mechanism with designated attributes. Permissible names and
   * values are mechanism specific.
   *
   * @param attributes a set of name-value pairs that describes the desired
   *          future behaviour of this instance.
   * @throws IllegalMechanismStateException if the instance is already
   *           initialised.
   * @throws SaslException if an exception occurs during the process.
   */
  public void init(final Map attributes) throws SaslException
  {
    if (state != -1)
      throw new IllegalMechanismStateException("init()");
    if (properties == null)
      properties = new HashMap();
    else
      properties.clear();
    if (attributes != null)
      {
        authorizationID = (String) attributes.get(Registry.SASL_AUTHORISATION_ID);
        protocol = (String) attributes.get(Registry.SASL_PROTOCOL);
        serverName = (String) attributes.get(Registry.SASL_SERVER_NAME);
        handler = (CallbackHandler) attributes.get(Registry.SASL_CALLBACK_HANDLER);
        channelBinding = (byte[]) attributes.get(Registry.SASL_CHANNEL_BINDING);
        properties.putAll(attributes);
      }
    else
      handler = null;

    if (authorizationID == null)
      authorizationID = "";
    if (protocol == null)
      protocol = "";
    if (serverName == null)
      serverName = "";
    if (channelBinding == null)
      channelBinding = new byte[0];
    initMechanism();
    complete = false;
    state = 0;
  }

  /**
   * Resets the mechanism instance for re-initialisation and use with other
   * characteristics.
   *
   * @throws SaslException if an exception occurs during the process.
   */
  public void reset() throws SaslException
  {
    resetMechanism();
    properties.clear();
    authorizationID = protocol = serverName = null;
    channelBinding = null;
    complete = false;
    state = -1;
  }
}