2021-09-20 18:20:01 +02:00

99 lines
2.8 KiB
C#

/*
Copyright (C) 2014-2019 de4dot@gmail.com
This file is part of dnSpy
dnSpy is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
dnSpy is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with dnSpy. If not, see <http://www.gnu.org/licenses/>.
*/
using System;
using System.IO;
using System.Security.Cryptography;
namespace dnSpy.Debugger.DotNet.Metadata {
readonly struct AssemblyHasher : IDisposable {
readonly HashAlgorithm hasher;
public AssemblyHasher(DmdAssemblyHashAlgorithm hashAlgo) {
switch (hashAlgo) {
case DmdAssemblyHashAlgorithm.MD5:
hasher = MD5.Create();
break;
case DmdAssemblyHashAlgorithm.None:
case DmdAssemblyHashAlgorithm.SHA1:
default:
hasher = SHA1.Create();
break;
case DmdAssemblyHashAlgorithm.SHA256:
hasher = SHA256.Create();
break;
case DmdAssemblyHashAlgorithm.SHA384:
hasher = SHA384.Create();
break;
case DmdAssemblyHashAlgorithm.SHA512:
hasher = SHA512.Create();
break;
}
}
public void Dispose() => (hasher as IDisposable)?.Dispose();
public static byte[]? Hash(byte[]? data, DmdAssemblyHashAlgorithm hashAlgo) {
if (data is null)
return null;
using (var asmHash = new AssemblyHasher(hashAlgo)) {
asmHash.Hash(data);
return asmHash.ComputeHash();
}
}
public void Hash(byte[] data) => Hash(data, 0, data.Length);
public void Hash(byte[] data, int offset, int length) {
if (hasher.TransformBlock(data, offset, length, data, offset) != length)
throw new IOException("Could not calculate hash");
}
public void Hash(Stream stream, uint length, byte[] buffer) {
while (length > 0) {
int len = length > (uint)buffer.Length ? buffer.Length : (int)length;
if (stream.Read(buffer, 0, len) != len)
throw new IOException("Could not read data");
Hash(buffer, 0, len);
length -= (uint)len;
}
}
public byte[] ComputeHash() {
hasher.TransformFinalBlock(new byte[0], 0, 0);
return hasher.Hash!;
}
public static byte[]? CreatePublicKeyToken(byte[]? publicKeyData) {
if (publicKeyData is null || publicKeyData.Length == 0)
return publicKeyData;
var hash = Hash(publicKeyData, DmdAssemblyHashAlgorithm.SHA1)!;
var pkt = new byte[8];
for (int i = 0; i < pkt.Length && i < hash.Length; i++)
pkt[i] = hash[hash.Length - i - 1];
return pkt;
}
}
}