mcs/class/Mono.Security/Mono.Security.Protocol.Tls/RecordProtocol.cs

   1 /* Transport Security Layer (TLS)\r
   2  * Copyright (c) 2003-2004 Carlos Guzman Alvarez\r
   3  * \r
   4  * Permission is hereby granted, free of charge, to any person \r
   5  * obtaining a copy of this software and associated documentation \r
   6  * files (the "Software"), to deal in the Software without restriction, \r
   7  * including without limitation the rights to use, copy, modify, merge, \r
   8  * publish, distribute, sublicense, and/or sell copies of the Software, \r
   9  * and to permit persons to whom the Software is furnished to do so, \r
  10  * subject to the following conditions:\r
  11  * \r
  12  * The above copyright notice and this permission notice shall be included \r
  13  * in all copies or substantial portions of the Software.\r
  14  * \r
  15  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, \r
  16  * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES \r
  17  * OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND \r
  18  * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT \r
  19  * HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, \r
  20  * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, \r
  21  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER \r
  22  * DEALINGS IN THE SOFTWARE.\r
  23  */\r
  24 \r
  25 using System;\r
  26 using System.IO;\r
  27 using System.Security.Cryptography;\r
  28 using System.Security.Cryptography.X509Certificates;\r
  29 \r
  30 using Mono.Security.Protocol.Tls.Handshake;\r
  31 \r
  32 namespace Mono.Security.Protocol.Tls\r
  33 {\r
  34         internal abstract class RecordProtocol\r
  35         {\r
  36                 #region Fields\r
  37 \r
  38                 protected Stream        innerStream;\r
  39                 protected Context       context;\r
  40 \r
  41                 #endregion\r
  42 \r
  43                 #region Properties\r
  44 \r
  45                 public Stream InnerStream\r
  46                 {\r
  47                         get { return this.innerStream; }\r
  48                         set { this.innerStream = value; }\r
  49                 }\r
  50 \r
  51                 public Context Context\r
  52                 {\r
  53                         get { return this.context; }\r
  54                         set { this.context = value; }\r
  55                 }\r
  56 \r
  57                 #endregion\r
  58 \r
  59                 #region Constructors\r
  60 \r
  61                 public RecordProtocol(Stream innerStream, Context context)\r
  62                 {\r
  63                         this.innerStream        = innerStream;\r
  64                         this.context            = context;\r
  65                 }\r
  66 \r
  67                 #endregion\r
  68 \r
  69                 #region Abstract Methods\r
  70 \r
  71                 public abstract void SendRecord(HandshakeType type);\r
  72                 protected abstract void ProcessHandshakeMessage(TlsStream handMsg);\r
  73                                 \r
  74                 #endregion\r
  75 \r
  76                 #region Reveive Record Methods\r
  77 \r
  78                 public byte[] ReceiveRecord()\r
  79                 {\r
  80                         if (this.context.ConnectionEnd)\r
  81                         {\r
  82                                 throw this.context.CreateException("The session is finished and it's no longer valid.");\r
  83                         }\r
  84                         \r
  85                         // Try to read the Record Content Type\r
  86                         int type = this.innerStream.ReadByte();\r
  87 \r
  88                         // There are no more data for read\r
  89                         if (type == -1)\r
  90                         {\r
  91                                 return null;\r
  92                         }\r
  93 \r
  94                         ContentType     contentType     = (ContentType)type;\r
  95                         short           protocol        = this.readShort();\r
  96                         short           length          = this.readShort();\r
  97                         \r
  98                         // Read Record data\r
  99                         int             received        = 0;\r
 100                         byte[]  buffer          = new byte[length];\r
 101                         while (received != length)\r
 102                         {\r
 103                                 received += this.innerStream.Read(\r
 104                                         buffer, received, buffer.Length - received);\r
 105                         }\r
 106 \r
 107                         TlsStream message = new TlsStream(buffer);\r
 108                 \r
 109                         // Check that the message has a valid protocol version\r
 110                         if (protocol != this.context.Protocol && \r
 111                                 this.context.ProtocolNegotiated)\r
 112                         {\r
 113                                 throw this.context.CreateException("Invalid protocol version on message received from server");\r
 114                         }\r
 115 \r
 116                         // Decrypt message contents if needed\r
 117                         if (contentType == ContentType.Alert && length == 2)\r
 118                         {\r
 119                         }\r
 120                         else\r
 121                         {\r
 122                                 if (this.context.IsActual &&\r
 123                                         contentType != ContentType.ChangeCipherSpec)\r
 124                                 {\r
 125                                         message = this.decryptRecordFragment(\r
 126                                                 contentType, \r
 127                                                 message.ToArray());\r
 128                                 }\r
 129                         }\r
 130 \r
 131                         // Set last handshake message received to None\r
 132                         this.context.LastHandshakeMsg = HandshakeType.None;\r
 133                         \r
 134                         // Process record\r
 135                         byte[] result = message.ToArray();\r
 136 \r
 137                         switch (contentType)\r
 138                         {\r
 139                                 case ContentType.Alert:\r
 140                                         this.processAlert(\r
 141                                                 (AlertLevel)message.ReadByte(),\r
 142                                                 (AlertDescription)message.ReadByte());\r
 143                                         break;\r
 144 \r
 145                                 case ContentType.ChangeCipherSpec:\r
 146                                         // Reset sequence numbers\r
 147                                         this.context.ReadSequenceNumber = 0;\r
 148                                         break;\r
 149 \r
 150                                 case ContentType.ApplicationData:\r
 151                                         break;\r
 152 \r
 153                                 case ContentType.Handshake:\r
 154                                         while (!message.EOF)\r
 155                                         {\r
 156                                                 this.ProcessHandshakeMessage(message);\r
 157                                         }\r
 158 \r
 159                                         // Update handshakes of current messages\r
 160                                         this.context.HandshakeMessages.Write(message.ToArray());\r
 161                                         break;\r
 162 \r
 163                                 default:\r
 164                                         throw this.context.CreateException("Unknown record received from server.");\r
 165                         }\r
 166 \r
 167                         return result;\r
 168                 }\r
 169 \r
 170                 private short readShort()\r
 171                 {\r
 172                         byte[] b = new byte[2];\r
 173                         this.innerStream.Read(b, 0, b.Length);\r
 174 \r
 175                         short val = BitConverter.ToInt16(b, 0);\r
 176 \r
 177                         return System.Net.IPAddress.HostToNetworkOrder(val);\r
 178                 }\r
 179 \r
 180                 private void processAlert(\r
 181                         AlertLevel                      alertLevel, \r
 182                         AlertDescription        alertDesc)\r
 183                 {\r
 184                         switch (alertLevel)\r
 185                         {\r
 186                                 case AlertLevel.Fatal:\r
 187                                         throw this.context.CreateException(alertLevel, alertDesc);                                      \r
 188 \r
 189                                 case AlertLevel.Warning:\r
 190                                 default:\r
 191                                 switch (alertDesc)\r
 192                                 {\r
 193                                         case AlertDescription.CloseNotify:\r
 194                                                 this.context.ConnectionEnd = true;\r
 195                                                 break;\r
 196                                 }\r
 197                                 break;\r
 198                         }\r
 199                 }\r
 200 \r
 201                 #endregion\r
 202 \r
 203                 #region Send Alert Methods\r
 204 \r
 205                 public void SendAlert(AlertDescription description)\r
 206                 {\r
 207                         this.SendAlert(new Alert(this.Context, description));\r
 208                 }\r
 209 \r
 210                 public void SendAlert(\r
 211                         AlertLevel                      level, \r
 212                         AlertDescription        description)\r
 213                 {\r
 214                         this.SendAlert(new Alert(this.Context, level, description));\r
 215                 }\r
 216 \r
 217                 public void SendAlert(Alert alert)\r
 218                 {                       \r
 219                         // Write record\r
 220                         this.SendRecord(ContentType.Alert, alert.ToArray());\r
 221 \r
 222                         // Update session\r
 223                         alert.Update();\r
 224 \r
 225                         // Reset message contents\r
 226                         alert.Reset();\r
 227                 }\r
 228 \r
 229                 #endregion\r
 230 \r
 231                 #region Send Record Methods\r
 232 \r
 233                 public void SendChangeCipherSpec()\r
 234                 {\r
 235                         // Send Change Cipher Spec message\r
 236                         this.SendRecord(ContentType.ChangeCipherSpec, new byte[] {1});\r
 237 \r
 238                         // Reset sequence numbers\r
 239                         this.context.WriteSequenceNumber = 0;\r
 240 \r
 241                         // Make the pending state to be the current state\r
 242                         this.context.IsActual = true;\r
 243 \r
 244                         // Send Finished message\r
 245                         this.SendRecord(HandshakeType.Finished);                        \r
 246                 }\r
 247 \r
 248                 public void SendRecord(ContentType contentType, byte[] recordData)\r
 249                 {\r
 250                         if (this.context.ConnectionEnd)\r
 251                         {\r
 252                                 throw this.context.CreateException("The session is finished and it's no longer valid.");\r
 253                         }\r
 254 \r
 255                         byte[] record = this.EncodeRecord(contentType, recordData);\r
 256 \r
 257                         this.innerStream.Write(record, 0, record.Length);\r
 258                 }\r
 259 \r
 260                 public byte[] EncodeRecord(ContentType contentType, byte[] recordData)\r
 261                 {\r
 262                         return this.EncodeRecord(\r
 263                                 contentType,\r
 264                                 recordData,\r
 265                                 0,\r
 266                                 recordData.Length);\r
 267                 }\r
 268 \r
 269                 public byte[] EncodeRecord(\r
 270                         ContentType     contentType, \r
 271                         byte[]          recordData,\r
 272                         int                     offset,\r
 273                         int                     count)\r
 274                 {\r
 275                         if (this.context.ConnectionEnd)\r
 276                         {\r
 277                                 throw this.context.CreateException("The session is finished and it's no longer valid.");\r
 278                         }\r
 279 \r
 280                         TlsStream record = new TlsStream();\r
 281 \r
 282                         int     position = offset;\r
 283 \r
 284                         while (position < ( offset + count ))\r
 285                         {\r
 286                                 short   fragmentLength = 0;\r
 287                                 byte[]  fragment;\r
 288 \r
 289                                 if ((count - position) > Context.MAX_FRAGMENT_SIZE)\r
 290                                 {\r
 291                                         fragmentLength = Context.MAX_FRAGMENT_SIZE;\r
 292                                 }\r
 293                                 else\r
 294                                 {\r
 295                                         fragmentLength = (short)(count - position);\r
 296                                 }\r
 297 \r
 298                                 // Fill the fragment data\r
 299                                 fragment = new byte[fragmentLength];\r
 300                                 Buffer.BlockCopy(recordData, position, fragment, 0, fragmentLength);\r
 301 \r
 302                                 if (this.context.IsActual)\r
 303                                 {\r
 304                                         // Encrypt fragment\r
 305                                         fragment = this.encryptRecordFragment(contentType, fragment);\r
 306                                 }\r
 307 \r
 308                                 // Write tls message\r
 309                                 record.Write((byte)contentType);\r
 310                                 record.Write(this.context.Protocol);\r
 311                                 record.Write((short)fragment.Length);\r
 312                                 record.Write(fragment);\r
 313 \r
 314                                 // Update buffer position\r
 315                                 position += fragmentLength;\r
 316                         }\r
 317 \r
 318                         return record.ToArray();\r
 319                 }\r
 320                 \r
 321                 #endregion\r
 322 \r
 323                 #region Cryptography Methods\r
 324 \r
 325                 private byte[] encryptRecordFragment(\r
 326                         ContentType     contentType, \r
 327                         byte[]          fragment)\r
 328                 {\r
 329                         // Calculate message MAC\r
 330                         byte[] mac      = this.context.Cipher.ComputeClientRecordMAC(contentType, fragment);\r
 331 \r
 332                         // Encrypt the message\r
 333                         byte[] ecr = this.context.Cipher.EncryptRecord(fragment, mac);\r
 334 \r
 335                         // Set new IV\r
 336                         if (this.context.Cipher.CipherMode == CipherMode.CBC)\r
 337                         {\r
 338                                 byte[] iv = new byte[this.context.Cipher.IvSize];\r
 339                                 System.Array.Copy(ecr, ecr.Length - iv.Length, iv, 0, iv.Length);\r
 340                                 this.context.Cipher.UpdateClientCipherIV(iv);\r
 341                         }\r
 342 \r
 343                         // Update sequence number\r
 344                         this.context.WriteSequenceNumber++;\r
 345 \r
 346                         return ecr;\r
 347                 }\r
 348 \r
 349                 private TlsStream decryptRecordFragment(\r
 350                         ContentType     contentType, \r
 351                         byte[]          fragment)\r
 352                 {\r
 353                         byte[]  dcrFragment     = null;\r
 354                         byte[]  dcrMAC          = null;\r
 355 \r
 356                         // Decrypt message\r
 357                         this.context.Cipher.DecryptRecord(fragment, ref dcrFragment, ref dcrMAC);\r
 358 \r
 359                         // Set new IV\r
 360                         if (this.context.Cipher.CipherMode == CipherMode.CBC)\r
 361                         {\r
 362                                 byte[] iv = new byte[this.context.Cipher.IvSize];\r
 363                                 System.Array.Copy(fragment, fragment.Length - iv.Length, iv, 0, iv.Length);\r
 364                                 this.context.Cipher.UpdateServerCipherIV(iv);\r
 365                         }\r
 366                         \r
 367                         // Check MAC code\r
 368                         byte[] mac = this.context.Cipher.ComputeServerRecordMAC(contentType, dcrFragment);\r
 369 \r
 370                         // Check that the mac is correct\r
 371                         if (mac.Length != dcrMAC.Length)\r
 372                         {\r
 373                                 throw new TlsException("Invalid MAC received from server.");\r
 374                         }\r
 375                         for (int i = 0; i < mac.Length; i++)\r
 376                         {\r
 377                                 if (mac[i] != dcrMAC[i])\r
 378                                 {\r
 379                                         throw new TlsException("Invalid MAC received from server.");\r
 380                                 }\r
 381                         }\r
 382 \r
 383                         // Update sequence number\r
 384                         this.context.ReadSequenceNumber++;\r
 385 \r
 386                         return new TlsStream(dcrFragment);\r
 387                 }\r
 388 \r
 389                 #endregion\r
 390         }\r
 391 }\r