/*
Copyright (C) 2011-2012 de4dot@gmail.com
This file is part of de4dot.
de4dot 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.
de4dot 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 de4dot. If not, see .
*/
using System;
using System.IO;
using System.Security.Cryptography;
using Mono.Cecil;
using ICSharpCode.SharpZipLib.Zip.Compression;
using de4dot.blocks;
namespace de4dot.code.deobfuscators {
static class DeobUtils {
public static void decryptAndAddResources(ModuleDefinition module, string encryptedName, Func decryptResource) {
Log.v("Decrypting resources, name: {0}", Utils.toCsharpString(encryptedName));
var decryptedResourceData = decryptResource();
if (decryptedResourceData == null)
throw new ApplicationException("decryptedResourceData is null");
var resourceModule = ModuleDefinition.ReadModule(new MemoryStream(decryptedResourceData));
Log.indent();
foreach (var rsrc in resourceModule.Resources) {
Log.v("Adding decrypted resource {0}", Utils.toCsharpString(rsrc.Name));
module.Resources.Add(rsrc);
}
Log.deIndent();
}
public static T lookup(ModuleDefinition module, T def, string errorMessage) where T : MemberReference {
if (def == null)
return null;
var newDef = module.LookupToken(def.MetadataToken.ToInt32()) as T;
if (newDef == null)
throw new ApplicationException(errorMessage);
return newDef;
}
public static byte[] readModule(ModuleDefinition module) {
return Utils.readFile(module.FullyQualifiedName);
}
public static bool isCode(short[] nativeCode, byte[] code) {
if (nativeCode.Length != code.Length)
return false;
for (int i = 0; i < nativeCode.Length; i++) {
if (nativeCode[i] == -1)
continue;
if ((byte)nativeCode[i] != code[i])
return false;
}
return true;
}
public static byte[] aesDecrypt(byte[] data, byte[] key, byte[] iv) {
using (var aes = new RijndaelManaged { Mode = CipherMode.CBC }) {
using (var transform = aes.CreateDecryptor(key, iv)) {
return transform.TransformFinalBlock(data, 0, data.Length);
}
}
}
public static byte[] des3Decrypt(byte[] data, byte[] key, byte[] iv) {
using (var des3 = TripleDES.Create()) {
using (var transform = des3.CreateDecryptor(key, iv)) {
return transform.TransformFinalBlock(data, 0, data.Length);
}
}
}
public static byte[] desDecrypt(byte[] data, int start, int len, byte[] key, byte[] iv) {
using (var des = new DESCryptoServiceProvider()) {
using (var transform = des.CreateDecryptor(key, iv)) {
return transform.TransformFinalBlock(data, start, len);
}
}
}
// Code converted from C implementation @ http://en.wikipedia.org/wiki/XXTEA (btea() func)
public static void xxteaDecrypt(uint[] v, int n, uint[] key) {
const uint DELTA = 0x9E3779B9;
uint rounds = (uint)(6 + 52 / n);
uint sum = rounds * DELTA;
uint y = v[0];
uint z;
//#define MX (((z >> 5 ^ y << 2) + (y >> 3 ^ z << 4)) ^ ((sum ^ y) + (key[(p & 3) ^ e] ^ z)))
do {
int e = (int)((sum >> 2) & 3);
int p;
for (p = n - 1; p > 0; p--) {
z = v[p - 1];
y = v[p] -= (((z >> 5 ^ y << 2) + (y >> 3 ^ z << 4)) ^ ((sum ^ y) + (key[(p & 3) ^ e] ^ z)));
}
z = v[n - 1];
y = v[0] -= (((z >> 5 ^ y << 2) + (y >> 3 ^ z << 4)) ^ ((sum ^ y) + (key[(p & 3) ^ e] ^ z)));
} while ((sum -= DELTA) != 0);
}
public static string getExtension(ModuleKind kind) {
switch (kind) {
case ModuleKind.Dll:
return ".dll";
case ModuleKind.NetModule:
return ".netmodule";
case ModuleKind.Console:
case ModuleKind.Windows:
default:
return ".exe";
}
}
public static byte[] inflate(byte[] data, bool hasHeader) {
return inflate(data, 0, data.Length, hasHeader);
}
public static byte[] inflate(byte[] data, int start, int len, bool hasHeader) {
var buffer = new byte[0x1000];
var memStream = new MemoryStream();
var inflater = new Inflater(hasHeader);
inflater.SetInput(data, start, len);
while (true) {
int count = inflater.Inflate(buffer, 0, buffer.Length);
if (count == 0)
break;
memStream.Write(buffer, 0, count);
}
return memStream.ToArray();
}
public static EmbeddedResource getEmbeddedResourceFromCodeStrings(ModuleDefinition module, MethodDefinition method) {
foreach (var s in DotNetUtils.getCodeStrings(method)) {
var resource = DotNetUtils.getResource(module, s) as EmbeddedResource;
if (resource != null)
return resource;
}
return null;
}
public static int readVariableLengthInt32(BinaryReader reader) {
byte b = reader.ReadByte();
if ((b & 0x80) == 0)
return b;
if ((b & 0x40) == 0)
return (((int)b & 0x3F) << 8) + reader.ReadByte();
return (((int)b & 0x3F) << 24) +
((int)reader.ReadByte() << 16) +
((int)reader.ReadByte() << 8) +
reader.ReadByte();
}
}
}