ntlm.java

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/*
 * $Header: /home/jerenkrantz/tmp/commons/commons-convert/cvs/home/cvs/jakarta-commons//httpclient/src/java/org/apache/commons/httpclient/auth/NTLM.java,v 1.11 2004/05/13 04:02:00 mbecke Exp $
 * $Revision: 480424 $
 * $Date: 2006-11-29 06:56:49 +0100 (Wed, 29 Nov 2006) $
 *
 * ====================================================================
 *
 *  Licensed to the Apache Software Foundation (ASF) under one or more
 *  contributor license agreements.  See the NOTICE file distributed with
 *  this work for additional information regarding copyright ownership.
 *  The ASF licenses this file to You under the Apache License, Version 2.0
 *  (the "License"); you may not use this file except in compliance with
 *  the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 * ====================================================================
 *
 * This software consists of voluntary contributions made by many
 * individuals on behalf of the Apache Software Foundation.  For more
 * information on the Apache Software Foundation, please see
 * <http://www.apache.org/>.
 *
 */

package org.apache.commons.httpclient.auth;

import java.security.InvalidKeyException;
import java.security.NoSuchAlgorithmException;

import javax.crypto.BadPaddingException;
import javax.crypto.Cipher;
import javax.crypto.IllegalBlockSizeException;
import javax.crypto.NoSuchPaddingException;
import javax.crypto.spec.SecretKeySpec;

import org.apache.commons.codec.binary.Base64;
import org.apache.commons.httpclient.util.EncodingUtil;

/**
 * Provides an implementation of the NTLM authentication protocol.
 * <p>
 * This class provides methods for generating authentication
 * challenge responses for the NTLM authentication protocol.  The NTLM
 * protocol is a proprietary Microsoft protocol and as such no RFC
 * exists for it.  This class is based upon the reverse engineering
 * efforts of a wide range of people.</p>
 *
 * <p>Please note that an implementation of JCE must be correctly installed and configured when
 * using NTLM support.</p>
 *
 * <p>This class should not be used externally to HttpClient as it's API is specifically
 * designed to work with HttpClient's use case, in particular it's connection management.</p>
 *
 * @author <a href="mailto:[e-mail]">Adrian Sutton</a>
 * @author <a href="mailto:[e-mail]">Jeff Dever</a>
 * @author <a href="mailto:[e-mail]">Mike Bowler</a>
 *
 * @version $Revision: 480424 $ $Date: 2006-11-29 06:56:49 +0100 (Wed, 29 Nov 2006) $
 * @since 3.0
 */
final class NTLM {

    /** Character encoding */
    public static final String DEFAULT_CHARSET = "ASCII";

    /** The current response */
    private byte[] currentResponse;

    /** The current position */
    private int currentPosition = 0;

    /** The character set to use for encoding the credentials */
    private String credentialCharset = DEFAULT_CHARSET;
    
    /**
     * Returns the response for the given message.
     *
     * @param message the message that was received from the server.
     * @param username the username to authenticate with.
     * @param password the password to authenticate with.
     * @param host The host.
     * @param domain the NT domain to authenticate in.
     * @return The response.
     * @throws HttpException If the messages cannot be retrieved.
     */
    public final String getResponseFor(String message,
            String username, String password, String host, String domain)
            throws AuthenticationException {
                
        final String response;
        if (message == null || message.trim().equals("")) {
            response = getType1Message(host, domain);
        } else {
            response = getType3Message(username, password, host, domain,
                    parseType2Message(message));
        }
        return response;
    }

    /**
     * Return the cipher for the specified key.
     * @param key The key.
     * @return Cipher The cipher.
     * @throws AuthenticationException If the cipher cannot be retrieved.
     */
    private Cipher getCipher(byte[] key) throws AuthenticationException {
        try {
            final Cipher ecipher = Cipher.getInstance("DES/ECB/NoPadding");
            key = setupKey(key);
            ecipher.init(Cipher.ENCRYPT_MODE, new SecretKeySpec(key, "DES"));
            return ecipher;
        } catch (NoSuchAlgorithmException e) {
            throw new AuthenticationException("DES encryption is not available.", e);
        } catch (InvalidKeyException e) {
            throw new AuthenticationException("Invalid key for DES encryption.", e);
        } catch (NoSuchPaddingException e) {
            throw new AuthenticationException(
                "NoPadding option for DES is not available.", e);
        }
    }

    /** 
     * Adds parity bits to the key.
     * @param key56 The key
     * @return The modified key.
     */
    private byte[] setupKey(byte[] key56) {
        byte[] key = new byte[8];
        key[0] = (byte) ((key56[0] >> 1) & 0xff);
        key[1] = (byte) ((((key56[0] & 0x01) << 6) 
            | (((key56[1] & 0xff) >> 2) & 0xff)) & 0xff);
        key[2] = (byte) ((((key56[1] & 0x03) << 5) 
            | (((key56[2] & 0xff) >> 3) & 0xff)) & 0xff);
        key[3] = (byte) ((((key56[2] & 0x07) << 4) 
            | (((key56[3] & 0xff) >> 4) & 0xff)) & 0xff);
        key[4] = (byte) ((((key56[3] & 0x0f) << 3) 
            | (((key56[4] & 0xff) >> 5) & 0xff)) & 0xff);
        key[5] = (byte) ((((key56[4] & 0x1f) << 2) 
            | (((key56[5] & 0xff) >> 6) & 0xff)) & 0xff);
        key[6] = (byte) ((((key56[5] & 0x3f) << 1) 
            | (((key56[6] & 0xff) >> 7) & 0xff)) & 0xff);
        key[7] = (byte) (key56[6] & 0x7f);
        
        for (int i = 0; i < key.length; i++) {
            key[i] = (byte) (key[i] << 1);
        }
        return key;
    }

    /**
     * Encrypt the data.
     * @param key The key.
     * @param bytes The data
     * @return byte[] The encrypted data
     * @throws HttpException If {@link Cipher.doFinal(byte[])} fails
     */
    private byte[] encrypt(byte[] key, byte[] bytes)
        throws AuthenticationException {
        Cipher ecipher = getCipher(key);
        try {
            byte[] enc = ecipher.doFinal(bytes);
            return enc;
        } catch (IllegalBlockSizeException e) {
            throw new AuthenticationException("Invalid block size for DES encryption.", e);
        } catch (BadPaddingException e) {
            throw new AuthenticationException("Data not padded correctly for DES encryption.", e);
        }
    }

    /** 
     * Prepares the object to create a response of the given length.
     * @param length the length of the response to prepare.
     */
    private void prepareResponse(int length) {
        currentResponse = new byte[length];
        currentPosition = 0;
    }

    /** 
     * Adds the given byte to the response.
     * @param b the byte to add.
     */
    private void addByte(byte b) {
        currentResponse[currentPosition] = b;
        currentPosition++;
    }

    /** 
     * Adds the given bytes to the response.
     * @param bytes the bytes to add.
     */
    private void addBytes(byte[] bytes) {
        for (int i = 0; i < bytes.length; i++) {
            currentResponse[currentPosition] = bytes[i];
            currentPosition++;
        }
    }

    /** 
     * Returns the response that has been generated after shrinking the array if
     * required and base64 encodes the response.
     * @return The response as above.
     */
    private String getResponse() {
        byte[] resp;
        if (currentResponse.length > currentPosition) {
            byte[] tmp = new byte[currentPosition];
            for (int i = 0; i < currentPosition; i++) {
                tmp[i] = currentResponse[i];
            }
            resp = tmp;
        } else {
            resp = currentResponse;
        }
        return EncodingUtil.getAsciiString(Base64.encodeBase64(resp));
    }
    
    /**
     * Creates the first message (type 1 message) in the NTLM authentication sequence.
     * This message includes the user name, domain and host for the authentication session.
     *
     * @param host the computer name of the host requesting authentication.
     * @param domain The domain to authenticate with.
     * @return String the message to add to the HTTP request header.
     */
    public String getType1Message(String host, String domain) {
        host = host.toUpperCase();
        domain = domain.toUpperCase();
        byte[] hostBytes = EncodingUtil.getBytes(host, DEFAULT_CHARSET);
        byte[] domainBytes = EncodingUtil.getBytes(domain, DEFAULT_CHARSET);

        int finalLength = 32 + hostBytes.length + domainBytes.length;
        prepareResponse(finalLength);
        
        // The initial id string.
        byte[] protocol = EncodingUtil.getBytes("NTLMSSP", DEFAULT_CHARSET);
        addBytes(protocol);
        addByte((byte) 0);

        // Type
        addByte((byte) 1);
        addByte((byte) 0);
        addByte((byte) 0);
        addByte((byte) 0);

        // Flags
        addByte((byte) 6);
        addByte((byte) 82);
        addByte((byte) 0);
        addByte((byte) 0);

        // Domain length (first time).
        int iDomLen = domainBytes.length;
        byte[] domLen = convertShort(iDomLen);
        addByte(domLen[0]);
        addByte(domLen[1]);

        // Domain length (second time).
        addByte(domLen[0]);
        addByte(domLen[1]);

        // Domain offset.
        byte[] domOff = convertShort(hostBytes.length + 32);
        addByte(domOff[0]);
        addByte(domOff[1]);
        addByte((byte) 0);
        addByte((byte) 0);

        // Host length (first time).
        byte[] hostLen = convertShort(hostBytes.length);
        addByte(hostLen[0]);
        addByte(hostLen[1]);

        // Host length (second time).
        addByte(hostLen[0]);
        addByte(hostLen[1]);