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 //
   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.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                                 ClientSessionCache.Add (this.Context.ClientSettings.TargetHost, this.sessionId);
 103                                 this.Context.AbbreviatedHandshake = CompareSessionId (this.sessionId, this.Context.SessionId);
 104                         }
 105                         else
 106                         {
 107                                 this.Context.AbbreviatedHandshake = false;
 108                         }
 109
 110                         // Read cipher suite
 111                         short cipherCode = this.ReadInt16();
 112                         if (this.Context.SupportedCiphers.IndexOf(cipherCode) == -1)
 113                         {
 114                                 // The server has sent an invalid ciphersuite
 115                                 throw new TlsException(AlertDescription.InsuficientSecurity, "Invalid cipher suite received from server");
 116                         }
 117                         this.cipherSuite = this.Context.SupportedCiphers[cipherCode];
 118
 119                         // Read compression methods ( always 0 )
 120                         this.compressionMethod = (SecurityCompressionType)this.ReadByte();
 121                 }
 122
 123                 #endregion
 124
 125                 #region Private Methods
 126
 127                 private bool CompareSessionId (byte[] id1, byte[] id2)
 128                 {
 129                         // in our case both null can't exist (or be valid)
 130                         if ((id1 == null) || (id2 == null))
 131                                 return false;
 132
 133                         if (id1.Length != id2.Length)
 134                                 return false;
 135
 136                         for (int i = 0; i < id1.Length; i++) {
 137                                 if (id1 [i] != id2 [i])
 138                                         return false;
 139                         }
 140                         return true;
 141                 }
 142
 143                 private void processProtocol(short protocol)
 144                 {
 145                         SecurityProtocolType serverProtocol = this.Context.DecodeProtocolCode(protocol);
 146
 147                         if ((serverProtocol & this.Context.SecurityProtocolFlags) == serverProtocol ||
 148                                 (this.Context.SecurityProtocolFlags & SecurityProtocolType.Default) == SecurityProtocolType.Default)
 149                         {
 150                                 this.Context.SecurityProtocol = serverProtocol;
 151                                 this.Context.SupportedCiphers.Clear();
 152                                 this.Context.SupportedCiphers = null;
 153                                 this.Context.SupportedCiphers = CipherSuiteFactory.GetSupportedCiphers(serverProtocol);
 154
 155                                 DebugHelper.WriteLine("Selected protocol {0}", serverProtocol);
 156                         }
 157                         else
 158                         {
 159                                 throw new TlsException(
 160                                         AlertDescription.ProtocolVersion,
 161                                         "Incorrect protocol version received from server");
 162                         }
 163                 }
 164
 165                 #endregion
 166         }
 167 }