mcs/class/Mono.Security/Mono.Security.Protocol.Ntlm/ChallengeResponse.cs

   1 //
   2 // Mono.Security.Protocol.Ntlm.ChallengeResponse
   3 //      Implements Challenge Response for NTLM v1
   4 //
   5 // Author:
   6 //      Sebastien Pouliot <sebastien@ximian.com>
   7 //
   8 // (C) 2003 Motus Technologies Inc. (http://www.motus.com)
   9 // (C) 2004 Novell (http://www.novell.com)
  10 //
  11 // References
  12 // a.   NTLM Authentication Scheme for HTTP, Ronald Tschalär
  13 //      http://www.innovation.ch/java/ntlm.html
  14 // b.   The NTLM Authentication Protocol, Copyright © 2003 Eric Glass
  15 //      http://davenport.sourceforge.net/ntlm.html
  16 //
  17
  18 //
  19 // Permission is hereby granted, free of charge, to any person obtaining
  20 // a copy of this software and associated documentation files (the
  21 // "Software"), to deal in the Software without restriction, including
  22 // without limitation the rights to use, copy, modify, merge, publish,
  23 // distribute, sublicense, and/or sell copies of the Software, and to
  24 // permit persons to whom the Software is furnished to do so, subject to
  25 // the following conditions:
  26 //
  27 // The above copyright notice and this permission notice shall be
  28 // included in all copies or substantial portions of the Software.
  29 //
  30 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  31 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  32 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  33 // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  34 // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  35 // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  36 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  37 //
  38
  39 using System;
  40 using System.Globalization;
  41 using System.Security.Cryptography;
  42 using System.Text;
  43
  44 using Mono.Security.Cryptography;
  45
  46 namespace Mono.Security.Protocol.Ntlm {
  47
  48         [Obsolete (Type3Message.LegacyAPIWarning)]
  49 #if INSIDE_SYSTEM
  50         internal
  51 #else
  52         public
  53 #endif
  54         class ChallengeResponse : IDisposable {
  55
  56                 static private byte[] magic = { 0x4B, 0x47, 0x53, 0x21, 0x40, 0x23, 0x24, 0x25 };
  57
  58                 // This is the pre-encrypted magic value with a null DES key (0xAAD3B435B51404EE)
  59                 // Ref: http://packetstormsecurity.nl/Crackers/NT/l0phtcrack/l0phtcrack2.5-readme.html
  60                 static private byte[] nullEncMagic = { 0xAA, 0xD3, 0xB4, 0x35, 0xB5, 0x14, 0x04, 0xEE };
  61
  62                 private bool _disposed;
  63                 private byte[] _challenge;
  64                 private byte[] _lmpwd;
  65                 private byte[] _ntpwd;
  66
  67                 // constructors
  68
  69                 public ChallengeResponse ()
  70                 {
  71                         _disposed = false;
  72                         _lmpwd = new byte [21];
  73                         _ntpwd = new byte [21];
  74                 }
  75
  76                 public ChallengeResponse (string password, byte[] challenge) : this ()
  77                 {
  78                         Password = password;
  79                         Challenge = challenge;
  80                 }
  81
  82                 ~ChallengeResponse ()
  83                 {
  84                         if (!_disposed)
  85                                 Dispose ();
  86                 }
  87
  88                 // properties
  89
  90                 public string Password {
  91                         get { return null; }
  92                         set {
  93                                 if (_disposed)
  94                                         throw new ObjectDisposedException ("too late");
  95
  96                                 // create Lan Manager password
  97                                 DES des = DES.Create ();
  98                                 des.Mode = CipherMode.ECB;
  99                                 ICryptoTransform ct = null;
 100
 101                                 // Note: In .NET DES cannot accept a weak key
 102                                 // this can happen for a null password
 103                                 if ((value == null) || (value.Length < 1)) {
 104                                         Buffer.BlockCopy (nullEncMagic, 0, _lmpwd, 0, 8);
 105                                 }
 106                                 else {
 107                                         des.Key = PasswordToKey (value, 0);
 108                                         ct = des.CreateEncryptor ();
 109                                         ct.TransformBlock (magic, 0, 8, _lmpwd, 0);
 110                                 }
 111
 112                                 // and if a password has less than 8 characters
 113                                 if ((value == null) || (value.Length < 8)) {
 114                                         Buffer.BlockCopy (nullEncMagic, 0, _lmpwd, 8, 8);
 115                                 }
 116                                 else {
 117                                         des.Key = PasswordToKey (value, 7);
 118                                         ct = des.CreateEncryptor ();
 119                                         ct.TransformBlock (magic, 0, 8, _lmpwd, 8);
 120                                 }
 121
 122                                 // create NT password
 123                                 MD4 md4 = MD4.Create ();
 124                                 byte[] data = ((value == null) ? (new byte [0]) : (Encoding.Unicode.GetBytes (value)));
 125                                 byte[] hash = md4.ComputeHash (data);
 126                                 Buffer.BlockCopy (hash, 0, _ntpwd, 0, 16);
 127
 128                                 // clean up
 129                                 Array.Clear (data, 0, data.Length);
 130                                 Array.Clear (hash, 0, hash.Length);
 131                                 des.Clear ();
 132                         }
 133                 }
 134
 135                 public byte[] Challenge {
 136                         get { return null; }
 137                         set {
 138                                 if (value == null)
 139                                         throw new ArgumentNullException ("Challenge");
 140                                 if (_disposed)
 141                                         throw new ObjectDisposedException ("too late");
 142                                 // we don't want the caller to modify the value afterward
 143                                 _challenge = (byte[]) value.Clone ();
 144                         }
 145                 }
 146
 147                 public byte[] LM {
 148                         get {
 149                                 if (_disposed)
 150                                         throw new ObjectDisposedException ("too late");
 151
 152                                 return GetResponse (_lmpwd);
 153                         }
 154                 }
 155
 156                 public byte[] NT {
 157                         get {
 158                                 if (_disposed)
 159                                         throw new ObjectDisposedException ("too late");
 160
 161                                 return GetResponse (_ntpwd);
 162                         }
 163                 }
 164
 165                 // IDisposable method
 166
 167                 public void Dispose ()
 168                 {
 169                         Dispose (true);
 170                         GC.SuppressFinalize (this);
 171                 }
 172
 173                 private void Dispose (bool disposing)
 174                 {
 175                         if (!_disposed) {
 176                                 // cleanup our stuff
 177                                 Array.Clear (_lmpwd, 0, _lmpwd.Length);
 178                                 Array.Clear (_ntpwd, 0, _ntpwd.Length);
 179                                 if (_challenge != null)
 180                                         Array.Clear (_challenge, 0, _challenge.Length);
 181                                 _disposed = true;
 182                         }
 183                 }
 184
 185                 // private methods
 186
 187                 private byte[] GetResponse (byte[] pwd)
 188                 {
 189                         byte[] response = new byte [24];
 190                         DES des = DES.Create ();
 191                         des.Mode = CipherMode.ECB;
 192                         des.Key = PrepareDESKey (pwd, 0);
 193                         ICryptoTransform ct = des.CreateEncryptor ();
 194                         ct.TransformBlock (_challenge, 0, 8, response, 0);
 195                         des.Key = PrepareDESKey (pwd, 7);
 196                         ct = des.CreateEncryptor ();
 197                         ct.TransformBlock (_challenge, 0, 8, response, 8);
 198                         des.Key = PrepareDESKey (pwd, 14);
 199                         ct = des.CreateEncryptor ();
 200                         ct.TransformBlock (_challenge, 0, 8, response, 16);
 201                         return response;
 202                 }
 203
 204                 private byte[] PrepareDESKey (byte[] key56bits, int position)
 205                 {
 206                         // convert to 8 bytes
 207                         byte[] key = new byte [8];
 208                         key [0] = key56bits [position];
 209                         key [1] = (byte) ((key56bits [position] << 7)     | (key56bits [position + 1] >> 1));
 210                         key [2] = (byte) ((key56bits [position + 1] << 6) | (key56bits [position + 2] >> 2));
 211                         key [3] = (byte) ((key56bits [position + 2] << 5) | (key56bits [position + 3] >> 3));
 212                         key [4] = (byte) ((key56bits [position + 3] << 4) | (key56bits [position + 4] >> 4));
 213                         key [5] = (byte) ((key56bits [position + 4] << 3) | (key56bits [position + 5] >> 5));
 214                         key [6] = (byte) ((key56bits [position + 5] << 2) | (key56bits [position + 6] >> 6));
 215                         key [7] = (byte)  (key56bits [position + 6] << 1);
 216                         return key;
 217                 }
 218
 219                 private byte[] PasswordToKey (string password, int position)
 220                 {
 221                         byte[] key7 = new byte [7];
 222                         int len = System.Math.Min (password.Length - position, 7);
 223                         Encoding.ASCII.GetBytes (password.ToUpper (CultureInfo.CurrentCulture), position, len, key7, 0);
 224                         byte[] key8 = PrepareDESKey (key7, 0);
 225                         // cleanup intermediate key material
 226                         Array.Clear (key7, 0, key7.Length);
 227                         return key8;
 228                 }
 229         }
 230 }