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 // Copyright (C) 2006 Novell, Inc (http://www.novell.com)
   4 //
   5 // Permission is hereby granted, free of charge, to any person obtaining
   6 // a copy of this software and associated documentation files (the
   7 // "Software"), to deal in the Software without restriction, including
   8 // without limitation the rights to use, copy, modify, merge, publish,
   9 // distribute, sublicense, and/or sell copies of the Software, and to
  10 // permit persons to whom the Software is furnished to do so, subject to
  11 // the following conditions:
  12 //
  13 // The above copyright notice and this permission notice shall be
  14 // included in all copies or substantial portions of the Software.
  15 //
  16 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  17 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  18 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  19 // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  20 // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  21 // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  22 // WITH THE SOFTWARE OR THE USE OR OTHER 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.Negotiating.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                         int clen = this.Context.ClientRandom.Length;
  67                         int slen = this.Context.ServerRandom.Length;
  68                         int rlen = clen + slen;
  69                         byte[] cs = new byte[rlen];
  70                         Buffer.BlockCopy (this.Context.ClientRandom, 0, cs, 0, clen);
  71                         Buffer.BlockCopy (this.Context.ServerRandom, 0, cs, clen, slen);
  72                         this.Context.RandomCS = cs;
  73
  74                         // Server Random + Client Random
  75                         byte[] sc = new byte[rlen];
  76                         Buffer.BlockCopy (this.Context.ServerRandom, 0, sc, 0, slen);
  77                         Buffer.BlockCopy (this.Context.ClientRandom, 0, sc, slen, clen);
  78                         this.Context.RandomSC = sc;
  79                 }
  80
  81                 #endregion
  82
  83                 #region Protected Methods
  84
  85                 protected override void ProcessAsSsl3()
  86                 {
  87                         this.ProcessAsTls1();
  88                 }
  89
  90                 protected override void ProcessAsTls1()
  91                 {
  92                         // Read protocol version
  93                         this.processProtocol(this.ReadInt16());
  94
  95                         // Read random  - Unix time + Random bytes
  96                         this.random     = this.ReadBytes(32);
  97
  98                         // Read Session id
  99                         int length = (int) ReadByte ();
 100                         if (length > 0)
 101                         {
 102                                 this.sessionId = this.ReadBytes(length);
 103                                 ClientSessionCache.Add (this.Context.ClientSettings.TargetHost, this.sessionId);
 104                                 this.Context.AbbreviatedHandshake = Compare (this.sessionId, this.Context.SessionId);
 105                         }
 106                         else
 107                         {
 108                                 this.Context.AbbreviatedHandshake = false;
 109                         }
 110
 111                         // Read cipher suite
 112                         short cipherCode = this.ReadInt16();
 113                         if (this.Context.SupportedCiphers.IndexOf(cipherCode) == -1)
 114                         {
 115                                 // The server has sent an invalid ciphersuite
 116                                 throw new TlsException(AlertDescription.InsuficientSecurity, "Invalid cipher suite received from server");
 117                         }
 118                         this.cipherSuite = this.Context.SupportedCiphers[cipherCode];
 119
 120                         // Read compression methods ( always 0 )
 121                         this.compressionMethod = (SecurityCompressionType)this.ReadByte();
 122                 }
 123
 124                 #endregion
 125
 126                 #region Private Methods
 127
 128                 private void processProtocol(short protocol)
 129                 {
 130                         SecurityProtocolType serverProtocol = this.Context.DecodeProtocolCode(protocol);
 131
 132                         if ((serverProtocol & this.Context.SecurityProtocolFlags) == serverProtocol ||
 133                                 (this.Context.SecurityProtocolFlags & SecurityProtocolType.Default) == SecurityProtocolType.Default)
 134                         {
 135                                 this.Context.SecurityProtocol = serverProtocol;
 136                                 this.Context.SupportedCiphers.Clear();
 137                                 this.Context.SupportedCiphers = null;
 138                                 this.Context.SupportedCiphers = CipherSuiteFactory.GetSupportedCiphers(serverProtocol);
 139
 140                                 DebugHelper.WriteLine("Selected protocol {0}", serverProtocol);
 141                         }
 142                         else
 143                         {
 144                                 throw new TlsException(
 145                                         AlertDescription.ProtocolVersion,
 146                                         "Incorrect protocol version received from server");
 147                         }
 148                 }
 149
 150                 #endregion
 151         }
 152 }