mcs/class/Mono.Security/Mono.Security.Protocol.Tls.Handshake.Client/TlsServerHello.cs

   1 /* Transport Security Layer (TLS)
   2  * Copyright (c) 2003-2004 Carlos Guzman Alvarez
   3  *
   4  * Permission is hereby granted, free of charge, to any person
   5  * obtaining a copy of this software and associated documentation
   6  * files (the "Software"), to deal in the Software without restriction,
   7  * including without limitation the rights to use, copy, modify, merge,
   8  * publish, distribute, sublicense, and/or sell copies of the Software,
   9  * and to permit persons to whom the Software is furnished to do so,
  10  * subject to the following conditions:
  11  *
  12  * The above copyright notice and this permission notice shall be included
  13  * in all copies or substantial portions of the Software.
  14  *
  15  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  16  * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
  17  * OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  18  * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
  19  * HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
  20  * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  21  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
  22  * DEALINGS IN THE SOFTWARE.
  23  */
  24
  25 using System;
  26
  27 namespace Mono.Security.Protocol.Tls.Handshake.Client
  28 {
  29         internal class TlsServerHello : HandshakeMessage
  30         {
  31                 #region Fields
  32
  33                 private SecurityCompressionType compressionMethod;
  34                 private byte[]                                  random;
  35                 private byte[]                                  sessionId;
  36                 private CipherSuite     cipherSuite;
  37
  38                 #endregion
  39
  40                 #region Constructors
  41
  42                 public TlsServerHello(Context context, byte[] buffer)
  43                         : base(context, HandshakeType.ServerHello, buffer)
  44                 {
  45                 }
  46
  47                 #endregion
  48
  49                 #region Methods
  50
  51                 public override void Update()
  52                 {
  53                         base.Update();
  54
  55                         this.Context.SessionId                  = this.sessionId;
  56                         this.Context.ServerRandom               = this.random;
  57                         this.Context.Cipher                             = this.cipherSuite;
  58                         this.Context.CompressionMethod  = this.compressionMethod;
  59                         this.Context.ProtocolNegotiated = true;
  60
  61                         DebugHelper.WriteLine("Selected Cipher Suite {0}", this.cipherSuite.Name);
  62                         DebugHelper.WriteLine("Client random", this.Context.ClientRandom);
  63                         DebugHelper.WriteLine("Server random", this.Context.ServerRandom);
  64
  65                         // Compute ClientRandom + ServerRandom
  66                         TlsStream random = new TlsStream();
  67                         random.Write(this.Context.ClientRandom);
  68                         random.Write(this.Context.ServerRandom);
  69                         this.Context.RandomCS = random.ToArray();
  70
  71                         // Server Random + Client Random
  72                         random.Reset();
  73                         random.Write(this.Context.ServerRandom);
  74                         random.Write(this.Context.ClientRandom);
  75
  76                         this.Context.RandomSC = random.ToArray();
  77                         random.Reset();
  78                 }
  79
  80                 #endregion
  81
  82                 #region Protected Methods
  83
  84                 protected override void ProcessAsSsl3()
  85                 {
  86                         this.ProcessAsTls1();
  87                 }
  88
  89                 protected override void ProcessAsTls1()
  90                 {
  91                         // Read protocol version
  92                         this.processProtocol(this.ReadInt16());
  93
  94                         // Read random  - Unix time + Random bytes
  95                         this.random     = this.ReadBytes(32);
  96
  97                         // Read Session id
  98                         int length = (int)ReadByte();
  99                         if (length > 0)
 100                         {
 101                                 this.sessionId = this.ReadBytes(length);
 102                         }
 103
 104                         // Read cipher suite
 105                         short cipherCode = this.ReadInt16();
 106                         if (this.Context.SupportedCiphers.IndexOf(cipherCode) == -1)
 107                         {
 108                                 // The server has sent an invalid ciphersuite
 109                                 throw new TlsException(AlertDescription.InsuficientSecurity, "Invalid cipher suite received from server");
 110                         }
 111                         this.cipherSuite = this.Context.SupportedCiphers[cipherCode];
 112
 113                         // Read compression methods ( always 0 )
 114                         this.compressionMethod = (SecurityCompressionType)this.ReadByte();
 115                 }
 116
 117                 #endregion
 118
 119                 #region Private Methods
 120
 121                 private void processProtocol(short protocol)
 122                 {
 123                         SecurityProtocolType serverProtocol = this.Context.DecodeProtocolCode(protocol);
 124
 125                         if ((serverProtocol & this.Context.SecurityProtocolFlags) == serverProtocol ||
 126                                 (this.Context.SecurityProtocolFlags & SecurityProtocolType.Default) == SecurityProtocolType.Default)
 127                         {
 128                                 this.Context.SecurityProtocol = serverProtocol;
 129                                 this.Context.SupportedCiphers.Clear();
 130                                 this.Context.SupportedCiphers = null;
 131                                 this.Context.SupportedCiphers = CipherSuiteFactory.GetSupportedCiphers(serverProtocol);
 132
 133                                 DebugHelper.WriteLine("Selected protocol {0}", serverProtocol);
 134                         }
 135                         else
 136                         {
 137                                 throw new TlsException(
 138                                         AlertDescription.ProtocolVersion,
 139                                         "Incorrect protocol version received from server");
 140                         }
 141                 }
 142
 143                 #endregion
 144         }
 145 }