source: branches/2901_StaticSelectionMethods/HeuristicLab.ExtLibs/HeuristicLab.Cecil/0.9.5/Mono.Cecil-0.9.5/Mono.Cecil/Mono.Security.Cryptography/CryptoService.cs

//
// CryptoService.cs
//
// Author:
//   Jb Evain (jbevain@gmail.com)
//
// Copyright (c) 2008 - 2011 Jb Evain
//
// 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.Reflection;
using System.Security.Cryptography;

#if !READ_ONLY

#if !SILVERLIGHT && !CF
using System.Runtime.Serialization;
using Mono.Security.Cryptography;
#endif

using Mono.Cecil.PE;

namespace Mono.Cecil {

  // Most of this code has been adapted
  // from Jeroen Frijters' fantastic work
  // in IKVM.Reflection.Emit. Thanks!

  static class CryptoService {

#if !SILVERLIGHT && !CF
    public static void StrongName (Stream stream, ImageWriter writer, StrongNameKeyPair key_pair)
    {
      int strong_name_pointer;

      var strong_name = CreateStrongName (key_pair, HashStream (stream, writer, out strong_name_pointer));
      PatchStrongName (stream, strong_name_pointer, strong_name);
    }

    static void PatchStrongName (Stream stream, int strong_name_pointer, byte [] strong_name)
    {
      stream.Seek (strong_name_pointer, SeekOrigin.Begin);
      stream.Write (strong_name, 0, strong_name.Length);
    }

    static byte [] CreateStrongName (StrongNameKeyPair key_pair, byte [] hash)
    {
      const string hash_algo = "SHA1";

      using (var rsa = key_pair.CreateRSA ()) {
        var formatter = new RSAPKCS1SignatureFormatter (rsa);
        formatter.SetHashAlgorithm (hash_algo);

        byte [] signature = formatter.CreateSignature (hash);
        Array.Reverse (signature);

        return signature;
      }
    }

    static byte [] HashStream (Stream stream, ImageWriter writer, out int strong_name_pointer)
    {
      const int buffer_size = 8192;

      var text = writer.text;
      var header_size = (int) writer.GetHeaderSize ();
      var text_section_pointer = (int) text.PointerToRawData;
      var strong_name_directory = writer.GetStrongNameSignatureDirectory ();

      if (strong_name_directory.Size == 0)
        throw new InvalidOperationException ();

      strong_name_pointer = (int) (text_section_pointer
        + (strong_name_directory.VirtualAddress - text.VirtualAddress));
      var strong_name_length = (int) strong_name_directory.Size;

      var sha1 = new SHA1Managed ();
      var buffer = new byte [buffer_size];
      using (var crypto_stream = new CryptoStream (Stream.Null, sha1, CryptoStreamMode.Write)) {

        stream.Seek (0, SeekOrigin.Begin);
        CopyStreamChunk (stream, crypto_stream, buffer, header_size);

        stream.Seek (text_section_pointer, SeekOrigin.Begin);
        CopyStreamChunk (stream, crypto_stream, buffer, (int) strong_name_pointer - text_section_pointer);

        stream.Seek (strong_name_length, SeekOrigin.Current);
        CopyStreamChunk (stream, crypto_stream, buffer, (int) (stream.Length - (strong_name_pointer + strong_name_length)));
      }

      return sha1.Hash;
    }
#endif
    static void CopyStreamChunk (Stream stream, Stream dest_stream, byte [] buffer, int length)
    {
      while (length > 0) {
        int read = stream.Read (buffer, 0, System.Math.Min (buffer.Length, length));
        dest_stream.Write (buffer, 0, read);
        length -= read;
      }
    }

    public static byte [] ComputeHash (string file)
    {
      if (!File.Exists (file))
        return Empty<byte>.Array;

      const int buffer_size = 8192;

      var sha1 = new SHA1Managed ();

      using (var stream = new FileStream (file, FileMode.Open, FileAccess.Read, FileShare.Read)) {

        var buffer = new byte [buffer_size];

        using (var crypto_stream = new CryptoStream (Stream.Null, sha1, CryptoStreamMode.Write))
          CopyStreamChunk (stream, crypto_stream, buffer, (int) stream.Length);
      }

      return sha1.Hash;
    }
  }

#if !SILVERLIGHT && !CF
  static partial class Mixin {

    public static RSA CreateRSA (this StrongNameKeyPair key_pair)
    {
      byte [] key;
      string key_container;

      if (!TryGetKeyContainer (key_pair, out key, out key_container))
        return CryptoConvert.FromCapiKeyBlob (key);

      var parameters = new CspParameters {
        Flags = CspProviderFlags.UseMachineKeyStore,
        KeyContainerName = key_container,
        KeyNumber = 2,
      };

      return new RSACryptoServiceProvider (parameters);
    }

    static bool TryGetKeyContainer (ISerializable key_pair, out byte [] key, out string key_container)
    {
      var info = new SerializationInfo (typeof (StrongNameKeyPair), new FormatterConverter ());
      key_pair.GetObjectData (info, new StreamingContext ());

      key = (byte []) info.GetValue ("_keyPairArray", typeof (byte []));
      key_container = info.GetString ("_keyPairContainer");
      return key_container != null;
    }
  }
#endif
}

#endif