/**
    * Copyright 2014 Internet2
    *
    * Licensed 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.
   */
  /*
   * $Header: /home/hagleyj/i2mi/grouper-misc/grouperClient/src/ext/edu/internet2/middleware/grouperClientExt/org/apache/commons/httpclient/auth/NTLM.java,v 1.1 2008-11-30 10:57:20 mchyzer Exp $
   * $Revision: 1.1 $
   * $Date: 2008-11-30 10:57:20 $
   *
   * ====================================================================
   *
   *  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 edu.internet2.middleware.grouperClientExt.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 edu.internet2.middleware.grouperClientExt.org.apache.commons.codec.binary.Base64;
  import edu.internet2.middleware.grouperClientExt.org.apache.commons.httpclient.HttpException;
  import edu.internet2.middleware.grouperClientExt.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:adrian@ephox.com">Adrian Sutton</a>
   * @author <a href="mailto:jsdever@apache.org">Jeff Dever</a>
   * @author <a href="mailto:mbowler@GargoyleSoftware.com">Mike Bowler</a>
   *
   * @version $Revision: 1.1 $ $Date: 2008-11-30 10:57:20 $
   * @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]);
 
         // Host offset (always 32).
         byte[] hostOff = convertShort(32);
         addByte(hostOff[0]);
         addByte(hostOff[1]);
         addByte((byte) 0);
         addByte((byte) 0);
 
         // Host String.
         addBytes(hostBytes);
 
         // Domain String.
         addBytes(domainBytes);
 
         return getResponse();
     }
 
     /** 
      * Extracts the server nonce out of the given message type 2.
      * 
      * @param message the String containing the base64 encoded message.
      * @return an array of 8 bytes that the server sent to be used when
      * hashing the password.
      */
     public byte[] parseType2Message(String message) {
         // Decode the message first.
         byte[] msg = Base64.decodeBase64(EncodingUtil.getBytes(message, DEFAULT_CHARSET));
         byte[] nonce = new byte[8];
         // The nonce is the 8 bytes starting from the byte in position 24.
         for (int i = 0; i < 8; i++) {
             nonce[i] = msg[i + 24];
         }
         return nonce;
     }
 
     /** 
      * Creates the type 3 message using the given server nonce.  The type 3 message includes all the
      * information for authentication, host, domain, username and the result of encrypting the
      * nonce sent by the server using the user's password as the key.
      *
      * @param user The user name.  This should not include the domain name.
      * @param password The password.
      * @param host The host that is originating the authentication request.
      * @param domain The domain to authenticate within.
      * @param nonce the 8 byte array the server sent.
      * @return The type 3 message.
      * @throws AuthenticationException If {@encrypt(byte[],byte[])} fails.
      */
     public String getType3Message(String user, String password,
             String host, String domain, byte[] nonce)
     throws AuthenticationException {
 
         int ntRespLen = 0;
         int lmRespLen = 24;
         domain = domain.toUpperCase();
         host = host.toUpperCase();
         user = user.toUpperCase();
         byte[] domainBytes = EncodingUtil.getBytes(domain, DEFAULT_CHARSET);
         byte[] hostBytes = EncodingUtil.getBytes(host, DEFAULT_CHARSET);
         byte[] userBytes = EncodingUtil.getBytes(user, credentialCharset);
         int domainLen = domainBytes.length;
         int hostLen = hostBytes.length;
         int userLen = userBytes.length;
         int finalLength = 64 + ntRespLen + lmRespLen + domainLen 
             + userLen + hostLen;
         prepareResponse(finalLength);
         byte[] ntlmssp = EncodingUtil.getBytes("NTLMSSP", DEFAULT_CHARSET);
         addBytes(ntlmssp);
         addByte((byte) 0);
         addByte((byte) 3);
         addByte((byte) 0);
         addByte((byte) 0);
         addByte((byte) 0);
 
         // LM Resp Length (twice)
         addBytes(convertShort(24));
         addBytes(convertShort(24));
 
         // LM Resp Offset
         addBytes(convertShort(finalLength - 24));
         addByte((byte) 0);
         addByte((byte) 0);
 
         // NT Resp Length (twice)
         addBytes(convertShort(0));
         addBytes(convertShort(0));
 
         // NT Resp Offset
         addBytes(convertShort(finalLength));
         addByte((byte) 0);
         addByte((byte) 0);
 
         // Domain length (twice)
         addBytes(convertShort(domainLen));
         addBytes(convertShort(domainLen));
         
         // Domain offset.
         addBytes(convertShort(64));
         addByte((byte) 0);
         addByte((byte) 0);
 
         // User Length (twice)
         addBytes(convertShort(userLen));
         addBytes(convertShort(userLen));
 
         // User offset
         addBytes(convertShort(64 + domainLen));
         addByte((byte) 0);
         addByte((byte) 0);
 
         // Host length (twice)
         addBytes(convertShort(hostLen));
         addBytes(convertShort(hostLen));
 
         // Host offset
         addBytes(convertShort(64 + domainLen + userLen));
 
         for (int i = 0; i < 6; i++) {
             addByte((byte) 0);
         }
 
         // Message length
         addBytes(convertShort(finalLength));
         addByte((byte) 0);
         addByte((byte) 0);
 
         // Flags
         addByte((byte) 6);
         addByte((byte) 82);
         addByte((byte) 0);
         addByte((byte) 0);
 
         addBytes(domainBytes);
         addBytes(userBytes);
         addBytes(hostBytes);
         addBytes(hashPassword(password, nonce));
         return getResponse();
     }
 
     /** 
      * Creates the LANManager and NT response for the given password using the
      * given nonce.
      * @param password the password to create a hash for.
      * @param nonce the nonce sent by the server.
      * @return The response.
      * @throws HttpException If {@link #encrypt(byte[],byte[])} fails.
      */
     private byte[] hashPassword(String password, byte[] nonce)
         throws AuthenticationException {
         byte[] passw = EncodingUtil.getBytes(password.toUpperCase(), credentialCharset);
         byte[] lmPw1 = new byte[7];
         byte[] lmPw2 = new byte[7];
 
         int len = passw.length;
         if (len > 7) {
             len = 7;
         }
 
         int idx;
         for (idx = 0; idx < len; idx++) {
             lmPw1[idx] = passw[idx];
         }
         for (; idx < 7; idx++) {
             lmPw1[idx] = (byte) 0;
         }
 
         len = passw.length;
         if (len > 14) {
             len = 14;
         }
         for (idx = 7; idx < len; idx++) {
             lmPw2[idx - 7] = passw[idx];
         }
         for (; idx < 14; idx++) {
             lmPw2[idx - 7] = (byte) 0;
         }
 
         // Create LanManager hashed Password
         byte[] magic = {
             (byte) 0x4B, (byte) 0x47, (byte) 0x53, (byte) 0x21, 
             (byte) 0x40, (byte) 0x23, (byte) 0x24, (byte) 0x25
         };
 
         byte[] lmHpw1;
         lmHpw1 = encrypt(lmPw1, magic);
 
         byte[] lmHpw2 = encrypt(lmPw2, magic);
 
         byte[] lmHpw = new byte[21];
         for (int i = 0; i < lmHpw1.length; i++) {
             lmHpw[i] = lmHpw1[i];
         }
         for (int i = 0; i < lmHpw2.length; i++) {
             lmHpw[i + 8] = lmHpw2[i];
         }
         for (int i = 0; i < 5; i++) {
             lmHpw[i + 16] = (byte) 0;
         }
 
         // Create the responses.
         byte[] lmResp = new byte[24];
         calcResp(lmHpw, nonce, lmResp);
 
         return lmResp;
     }
 
     /** 
      * Takes a 21 byte array and treats it as 3 56-bit DES keys.  The 8 byte
      * plaintext is encrypted with each key and the resulting 24 bytes are
      * stored in the results array.
      * 
      * @param keys The keys.
      * @param plaintext The plain text to encrypt.
      * @param results Where the results are stored.
      * @throws AuthenticationException If {@link #encrypt(byte[],byte[])} fails.
      */
     private void calcResp(byte[] keys, byte[] plaintext, byte[] results)
         throws AuthenticationException {
         byte[] keys1 = new byte[7];
         byte[] keys2 = new byte[7];
         byte[] keys3 = new byte[7];
         for (int i = 0; i < 7; i++) {
             keys1[i] = keys[i];
         }
 
         for (int i = 0; i < 7; i++) {
             keys2[i] = keys[i + 7];
         }
 
         for (int i = 0; i < 7; i++) {
             keys3[i] = keys[i + 14];
         }
         byte[] results1 = encrypt(keys1, plaintext);
 
         byte[] results2 = encrypt(keys2, plaintext);
 
         byte[] results3 = encrypt(keys3, plaintext);
 
         for (int i = 0; i < 8; i++) {
             results[i] = results1[i];
         }
         for (int i = 0; i < 8; i++) {
             results[i + 8] = results2[i];
         }
         for (int i = 0; i < 8; i++) {
             results[i + 16] = results3[i];
         }
     }
 
     /** 
      * Converts a given number to a two byte array in little endian order.
      * @param num the number to convert.
      * @return The byte representation of <i>num</i> in little endian order.
      */
     private byte[] convertShort(int num) {
         byte[] val = new byte[2];
         String hex = Integer.toString(num, 16);
         while (hex.length() < 4) {
             hex = "0" + hex;
         }
         String low = hex.substring(2, 4);
         String high = hex.substring(0, 2);
 
         val[0] = (byte) Integer.parseInt(low, 16);
         val[1] = (byte) Integer.parseInt(high, 16);
         return val;
     }
     
     /**
      * @return Returns the credentialCharset.
      */
     public String getCredentialCharset() {
         return credentialCharset;
     }
 
     /**
      * @param credentialCharset The credentialCharset to set.
      */
     public void setCredentialCharset(String credentialCharset) {
         this.credentialCharset = credentialCharset;
     }
 
 }