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// Transport Security Layer (TLS)
// Copyright (c) 2003-2004 Carlos Guzman Alvarez
// Copyright (C) 2006 Novell, Inc (http://www.novell.com)
//
// Permission is hereby granted, free of charge, to any person obtaining
// a copy of this software and associated documentation files (the
// "Software"), to deal in the Software without restriction, including
// without limitation the rights to use, copy, modify, merge, publish,
// distribute, sublicense, and/or sell copies of the Software, and to
// permit persons to whom the Software is furnished to do so, subject to
// the following conditions:
//
// The above copyright notice and this permission notice shall be
// included in all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
// EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
// NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
// LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
// OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
// WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
//
using System;
using System.IO;
using System.Security.Cryptography;
namespace Mono.Security.Protocol.Tls
{
internal class TlsCipherSuite : CipherSuite
{
private const int MacHeaderLength = 13;
private byte[] header;
#region Constructors
public TlsCipherSuite(
short code, string name, CipherAlgorithmType cipherAlgorithmType,
HashAlgorithmType hashAlgorithmType, ExchangeAlgorithmType exchangeAlgorithmType,
bool exportable, bool blockMode, byte keyMaterialSize,
byte expandedKeyMaterialSize, short effectiveKeyBytes,
byte ivSize, byte blockSize)
:base(code, name, cipherAlgorithmType, hashAlgorithmType,
exchangeAlgorithmType, exportable, blockMode, keyMaterialSize,
expandedKeyMaterialSize, effectiveKeyBytes, ivSize, blockSize)
{
}
#endregion
#region MAC Generation Methods
public override byte[] ComputeServerRecordMAC(ContentType contentType, byte[] fragment)
{
if (header == null)
header = new byte [MacHeaderLength];
ulong seqnum = (Context is ClientContext) ? Context.ReadSequenceNumber : Context.WriteSequenceNumber;
Write (header, 0, seqnum);
header [8] = (byte) contentType;
Write (header, 9, this.Context.Protocol);
Write (header, 11, (short)fragment.Length);
HashAlgorithm mac = this.ServerHMAC;
mac.TransformBlock (header, 0, header.Length, header, 0);
mac.TransformBlock (fragment, 0, fragment.Length, fragment, 0);
// hack, else the method will allocate a new buffer of the same length (negative half the optimization)
mac.TransformFinalBlock (CipherSuite.EmptyArray, 0, 0);
return mac.Hash;
}
public override byte[] ComputeClientRecordMAC(ContentType contentType, byte[] fragment)
{
if (header == null)
header = new byte [MacHeaderLength];
ulong seqnum = (Context is ClientContext) ? Context.WriteSequenceNumber : Context.ReadSequenceNumber;
Write (header, 0, seqnum);
header [8] = (byte) contentType;
Write (header, 9, this.Context.Protocol);
Write (header, 11, (short)fragment.Length);
HashAlgorithm mac = this.ClientHMAC;
mac.TransformBlock (header, 0, header.Length, header, 0);
mac.TransformBlock (fragment, 0, fragment.Length, fragment, 0);
// hack, else the method will allocate a new buffer of the same length (negative half the optimization)
mac.TransformFinalBlock (CipherSuite.EmptyArray, 0, 0);
return mac.Hash;
}
#endregion
#region Key Generation Methods
public override void ComputeMasterSecret(byte[] preMasterSecret)
{
// Create master secret
this.Context.MasterSecret = new byte[preMasterSecret.Length];
this.Context.MasterSecret = this.PRF(
preMasterSecret, "master secret", this.Context.RandomCS, 48);
DebugHelper.WriteLine(">>>> MasterSecret", this.Context.MasterSecret);
}
public override void ComputeKeys()
{
// Create keyblock
TlsStream keyBlock = new TlsStream(
this.PRF(
this.Context.MasterSecret,
"key expansion",
this.Context.RandomSC,
this.KeyBlockSize));
this.Context.Negotiating.ClientWriteMAC = keyBlock.ReadBytes(this.HashSize);
this.Context.Negotiating.ServerWriteMAC = keyBlock.ReadBytes(this.HashSize);
this.Context.ClientWriteKey = keyBlock.ReadBytes(this.KeyMaterialSize);
this.Context.ServerWriteKey = keyBlock.ReadBytes(this.KeyMaterialSize);
if (!this.IsExportable)
{
if (this.IvSize != 0)
{
this.Context.ClientWriteIV = keyBlock.ReadBytes(this.IvSize);
this.Context.ServerWriteIV = keyBlock.ReadBytes(this.IvSize);
}
else
{
this.Context.ClientWriteIV = CipherSuite.EmptyArray;
this.Context.ServerWriteIV = CipherSuite.EmptyArray;
}
}
else
{
// Generate final write keys
byte[] finalClientWriteKey = PRF(this.Context.ClientWriteKey, "client write key", this.Context.RandomCS, this.ExpandedKeyMaterialSize);
byte[] finalServerWriteKey = PRF(this.Context.ServerWriteKey, "server write key", this.Context.RandomCS, this.ExpandedKeyMaterialSize);
this.Context.ClientWriteKey = finalClientWriteKey;
this.Context.ServerWriteKey = finalServerWriteKey;
if (this.IvSize > 0)
{
// Generate IV block
byte[] ivBlock = PRF(CipherSuite.EmptyArray, "IV block", this.Context.RandomCS, this.IvSize*2);
// Generate IV keys
this.Context.ClientWriteIV = new byte[this.IvSize];
Buffer.BlockCopy(ivBlock, 0, this.Context.ClientWriteIV, 0, this.Context.ClientWriteIV.Length);
this.Context.ServerWriteIV = new byte[this.IvSize];
Buffer.BlockCopy(ivBlock, this.IvSize, this.Context.ServerWriteIV, 0, this.Context.ServerWriteIV.Length);
}
else
{
this.Context.ClientWriteIV = CipherSuite.EmptyArray;
this.Context.ServerWriteIV = CipherSuite.EmptyArray;
}
}
DebugHelper.WriteLine(">>>> KeyBlock", keyBlock.ToArray());
DebugHelper.WriteLine(">>>> ClientWriteKey", this.Context.ClientWriteKey);
DebugHelper.WriteLine(">>>> ClientWriteIV", this.Context.ClientWriteIV);
DebugHelper.WriteLine(">>>> ClientWriteMAC", this.Context.Negotiating.ClientWriteMAC);
DebugHelper.WriteLine(">>>> ServerWriteKey", this.Context.ServerWriteKey);
DebugHelper.WriteLine(">>>> ServerWriteIV", this.Context.ServerWriteIV);
DebugHelper.WriteLine(">>>> ServerWriteMAC", this.Context.Negotiating.ServerWriteMAC);
ClientSessionCache.SetContextInCache (this.Context);
// Clear no more needed data
keyBlock.Reset();
}
#endregion
}
}
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