/*
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.Collections.Generic;
using System.IO;
using System.IO.Compression;
using System.Security.Cryptography;
using dot10.DotNet;
using dot10.DotNet.Emit;
using ICSharpCode.SharpZipLib.Zip.Compression;
using de4dot.blocks;
namespace de4dot.code.deobfuscators {
static class DeobUtils {
public static void decryptAndAddResources(ModuleDef module, string encryptedName, Func decryptResource) {
Logger.v("Decrypting resources, name: {0}", Utils.toCsharpString(encryptedName));
var decryptedResourceData = decryptResource();
if (decryptedResourceData == null)
throw new ApplicationException("decryptedResourceData is null");
var resourceModule = ModuleDefMD.Load(decryptedResourceData);
Logger.Instance.indent();
foreach (var rsrc in resourceModule.Resources) {
Logger.v("Adding decrypted resource {0}", Utils.toCsharpString(rsrc.Name));
module.Resources.Add(rsrc);
}
Logger.Instance.deIndent();
}
public static T lookup(ModuleDefMD module, T def, string errorMessage) where T : class, ICodedToken {
if (def == null)
return null;
var newDef = module.ResolveToken(def.MDToken.Raw) as T;
if (newDef == null)
throw new ApplicationException(errorMessage);
return newDef;
}
public static byte[] readModule(ModuleDef module) {
return Utils.readFile(module.Location);
}
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[] md5Sum(byte[] data) {
return MD5.Create().ComputeHash(data);
}
public static byte[] sha1Sum(byte[] data) {
return SHA1.Create().ComputeHash(data);
}
public static byte[] sha256Sum(byte[] data) {
return SHA256.Create().ComputeHash(data);
}
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, uint[] key) {
const uint DELTA = 0x9E3779B9;
int n = v.Length;
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);
}
// Code converted from C implementation @ http://en.wikipedia.org/wiki/XTEA (decipher() func)
public static void xteaDecrypt(ref uint v0, ref uint v1, uint[] key, int rounds) {
const uint delta = 0x9E3779B9;
uint sum = (uint)(delta * rounds);
for (int i = 0; i < rounds; i++) {
v1 -= (((v0 << 4) ^ (v0 >> 5)) + v0) ^ (sum + key[(sum >> 11) & 3]);
sum -= delta;
v0 -= (((v1 << 4) ^ (v1 >> 5)) + v1) ^ (sum + key[sum & 3]);
}
}
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 noHeader) {
return inflate(data, 0, data.Length, noHeader);
}
public static byte[] inflate(byte[] data, int start, int len, bool noHeader) {
return inflate(data, start, len, new Inflater(noHeader));
}
public static byte[] inflate(byte[] data, Inflater inflater) {
return inflate(data, 0, data.Length, inflater);
}
public static byte[] inflate(byte[] data, int start, int len, Inflater inflater) {
var buffer = new byte[0x1000];
var memStream = new MemoryStream();
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 byte[] gunzip(Stream input, int decompressedSize) {
using (var gzip = new GZipStream(input, CompressionMode.Decompress)) {
var decompressed = new byte[decompressedSize];
if (gzip.Read(decompressed, 0, decompressedSize) != decompressedSize)
throw new ApplicationException("Could not gzip decompress");
return decompressed;
}
}
public static EmbeddedResource getEmbeddedResourceFromCodeStrings(ModuleDef module, MethodDef 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(byte[] data, ref int index) {
byte b = data[index++];
if ((b & 0x80) == 0)
return b;
if ((b & 0x40) == 0)
return (((int)b & 0x3F) << 8) + data[index++];
return (((int)b & 0x1F) << 24) +
((int)data[index++] << 16) +
((int)data[index++] << 8) +
data[index++];
}
public static bool hasInteger(MethodDef method, uint value) {
return hasInteger(method, (int)value);
}
public static bool hasInteger(MethodDef method, int value) {
return indexOfLdci4Instruction(method, value) >= 0;
}
public static int indexOfLdci4Instruction(MethodDef method, int value) {
if (method == null || method.Body == null)
return -1;
var instrs = method.Body.Instructions;
for (int i = 0; i < instrs.Count; i++) {
var instr = instrs[i];
if (!instr.IsLdcI4())
continue;
if (instr.GetLdcI4Value() == value)
return i;
}
return -1;
}
public static IEnumerable getInitCctors(ModuleDef module, int maxCctors) {
var cctor = DotNetUtils.getModuleTypeCctor(module);
if (cctor != null)
yield return cctor;
var entryPoint = module.EntryPoint;
if (entryPoint != null) {
cctor = entryPoint.DeclaringType.FindStaticConstructor();
if (cctor != null)
yield return cctor;
}
foreach (var type in module.GetTypes()) {
if (type == module.GlobalType)
continue;
cctor = type.FindStaticConstructor();
if (cctor == null)
continue;
yield return cctor;
if (!type.IsEnum && --maxCctors <= 0)
break;
}
}
public static List getAllResolveHandlers(MethodDef method) {
var list = new List();
if (method == null || method.Body == null)
return list;
foreach (var instr in method.Body.Instructions) {
if (instr.OpCode.Code != Code.Ldftn && instr.OpCode.Code != Code.Ldvirtftn)
continue;
var handler = instr.Operand as MethodDef;
if (handler == null)
continue;
if (!DotNetUtils.isMethod(handler, "System.Reflection.Assembly", "(System.Object,System.ResolveEventArgs)"))
continue;
list.Add(handler);
}
return list;
}
public static MethodDef getResolveMethod(MethodDef method) {
var handlers = DeobUtils.getAllResolveHandlers(method);
if (handlers.Count == 0)
return null;
return handlers[0];
}
}
}