271 lines
8.5 KiB
C#
271 lines
8.5 KiB
C#
/*
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Copyright (C) 2011-2012 de4dot@gmail.com
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This file is part of de4dot.
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de4dot is free software: you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation, either version 3 of the License, or
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(at your option) any later version.
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de4dot is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with de4dot. If not, see <http://www.gnu.org/licenses/>.
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*/
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using System;
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using System.Collections.Generic;
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using System.IO;
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using System.IO.Compression;
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using System.Security.Cryptography;
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using Mono.Cecil;
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using Mono.Cecil.Cil;
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using ICSharpCode.SharpZipLib.Zip.Compression;
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using de4dot.blocks;
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namespace de4dot.code.deobfuscators {
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static class DeobUtils {
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public static void decryptAndAddResources(ModuleDefinition module, string encryptedName, Func<byte[]> decryptResource) {
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Log.v("Decrypting resources, name: {0}", Utils.toCsharpString(encryptedName));
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var decryptedResourceData = decryptResource();
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if (decryptedResourceData == null)
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throw new ApplicationException("decryptedResourceData is null");
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var resourceModule = ModuleDefinition.ReadModule(new MemoryStream(decryptedResourceData));
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Log.indent();
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foreach (var rsrc in resourceModule.Resources) {
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Log.v("Adding decrypted resource {0}", Utils.toCsharpString(rsrc.Name));
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module.Resources.Add(rsrc);
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}
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Log.deIndent();
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}
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public static T lookup<T>(ModuleDefinition module, T def, string errorMessage) where T : MemberReference {
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if (def == null)
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return null;
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var newDef = module.LookupToken(def.MetadataToken.ToInt32()) as T;
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if (newDef == null)
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throw new ApplicationException(errorMessage);
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return newDef;
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}
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public static ModuleReference lookup(ModuleDefinition module, ModuleReference other, string errorMessage) {
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if (other == null)
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return null;
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foreach (var modRef in module.ModuleReferences) {
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if (modRef.MetadataToken.ToInt32() == other.MetadataToken.ToInt32())
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return modRef;
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}
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throw new ApplicationException(errorMessage);
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}
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public static byte[] readModule(ModuleDefinition module) {
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return Utils.readFile(module.FullyQualifiedName);
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}
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public static bool isCode(short[] nativeCode, byte[] code) {
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if (nativeCode.Length != code.Length)
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return false;
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for (int i = 0; i < nativeCode.Length; i++) {
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if (nativeCode[i] == -1)
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continue;
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if ((byte)nativeCode[i] != code[i])
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return false;
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}
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return true;
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}
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public static byte[] aesDecrypt(byte[] data, byte[] key, byte[] iv) {
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using (var aes = new RijndaelManaged { Mode = CipherMode.CBC }) {
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using (var transform = aes.CreateDecryptor(key, iv)) {
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return transform.TransformFinalBlock(data, 0, data.Length);
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}
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}
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}
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public static byte[] des3Decrypt(byte[] data, byte[] key, byte[] iv) {
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using (var des3 = TripleDES.Create()) {
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using (var transform = des3.CreateDecryptor(key, iv)) {
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return transform.TransformFinalBlock(data, 0, data.Length);
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}
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}
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}
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public static byte[] desDecrypt(byte[] data, int start, int len, byte[] key, byte[] iv) {
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using (var des = new DESCryptoServiceProvider()) {
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using (var transform = des.CreateDecryptor(key, iv)) {
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return transform.TransformFinalBlock(data, start, len);
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}
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}
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}
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// Code converted from C implementation @ http://en.wikipedia.org/wiki/XXTEA (btea() func)
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public static void xxteaDecrypt(uint[] v, uint[] key) {
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const uint DELTA = 0x9E3779B9;
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int n = v.Length;
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uint rounds = (uint)(6 + 52 / n);
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uint sum = rounds * DELTA;
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uint y = v[0];
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uint z;
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//#define MX (((z >> 5 ^ y << 2) + (y >> 3 ^ z << 4)) ^ ((sum ^ y) + (key[(p & 3) ^ e] ^ z)))
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do {
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int e = (int)((sum >> 2) & 3);
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int p;
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for (p = n - 1; p > 0; p--) {
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z = v[p - 1];
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y = v[p] -= (((z >> 5 ^ y << 2) + (y >> 3 ^ z << 4)) ^ ((sum ^ y) + (key[(p & 3) ^ e] ^ z)));
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}
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z = v[n - 1];
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y = v[0] -= (((z >> 5 ^ y << 2) + (y >> 3 ^ z << 4)) ^ ((sum ^ y) + (key[(p & 3) ^ e] ^ z)));
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} while ((sum -= DELTA) != 0);
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}
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public static string getExtension(ModuleKind kind) {
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switch (kind) {
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case ModuleKind.Dll:
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return ".dll";
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case ModuleKind.NetModule:
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return ".netmodule";
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case ModuleKind.Console:
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case ModuleKind.Windows:
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default:
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return ".exe";
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}
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}
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public static byte[] inflate(byte[] data, bool hasHeader) {
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return inflate(data, 0, data.Length, hasHeader);
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}
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public static byte[] inflate(byte[] data, int start, int len, bool hasHeader) {
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var buffer = new byte[0x1000];
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var memStream = new MemoryStream();
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var inflater = new Inflater(hasHeader);
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inflater.SetInput(data, start, len);
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while (true) {
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int count = inflater.Inflate(buffer, 0, buffer.Length);
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if (count == 0)
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break;
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memStream.Write(buffer, 0, count);
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}
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return memStream.ToArray();
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}
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public static byte[] gunzip(Stream input, int decompressedSize) {
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using (var gzip = new GZipStream(input, CompressionMode.Decompress)) {
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var decompressed = new byte[decompressedSize];
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if (gzip.Read(decompressed, 0, decompressedSize) != decompressedSize)
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throw new ApplicationException("Could not gzip decompress");
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return decompressed;
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}
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}
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public static EmbeddedResource getEmbeddedResourceFromCodeStrings(ModuleDefinition module, MethodDefinition method) {
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foreach (var s in DotNetUtils.getCodeStrings(method)) {
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var resource = DotNetUtils.getResource(module, s) as EmbeddedResource;
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if (resource != null)
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return resource;
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}
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return null;
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}
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public static int readVariableLengthInt32(BinaryReader reader) {
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byte b = reader.ReadByte();
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if ((b & 0x80) == 0)
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return b;
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if ((b & 0x40) == 0)
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return (((int)b & 0x3F) << 8) + reader.ReadByte();
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return (((int)b & 0x3F) << 24) +
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((int)reader.ReadByte() << 16) +
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((int)reader.ReadByte() << 8) +
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reader.ReadByte();
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}
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public static int readVariableLengthInt32(byte[] data, ref int index) {
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byte b = data[index++];
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if ((b & 0x80) == 0)
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return b;
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if ((b & 0x40) == 0)
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return (((int)b & 0x3F) << 8) + data[index++];
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return (((int)b & 0x3F) << 24) +
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((int)data[index++] << 16) +
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((int)data[index++] << 8) +
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data[index++];
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}
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public static bool hasInteger(MethodDefinition method, uint value) {
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return hasInteger(method, (int)value);
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}
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public static bool hasInteger(MethodDefinition method, int value) {
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return indexOfLdci4Instruction(method, value) >= 0;
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}
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public static int indexOfLdci4Instruction(MethodDefinition method, int value) {
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if (method == null || method.Body == null)
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return -1;
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var instrs = method.Body.Instructions;
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for (int i = 0; i < instrs.Count; i++) {
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var instr = instrs[i];
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if (!DotNetUtils.isLdcI4(instr))
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continue;
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if (DotNetUtils.getLdcI4Value(instr) == value)
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return i;
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}
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return -1;
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}
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public static IEnumerable<MethodDefinition> getInitCctors(ModuleDefinition module, int maxCctors) {
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var cctor = DotNetUtils.getModuleTypeCctor(module);
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if (cctor != null)
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yield return cctor;
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var entryPoint = module.EntryPoint;
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if (entryPoint != null) {
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cctor = DotNetUtils.getMethod(entryPoint.DeclaringType, ".cctor");
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if (cctor != null)
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yield return cctor;
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}
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foreach (var type in module.GetTypes()) {
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if (type == DotNetUtils.getModuleType(module))
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continue;
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cctor = DotNetUtils.getMethod(type, ".cctor");
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if (cctor == null)
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continue;
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yield return cctor;
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if (!type.IsEnum && --maxCctors <= 0)
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break;
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}
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}
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public static List<MethodDefinition> getAllResolveHandlers(MethodDefinition method) {
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var list = new List<MethodDefinition>();
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if (method == null || method.Body == null)
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return list;
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foreach (var instr in method.Body.Instructions) {
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if (instr.OpCode.Code != Code.Ldftn && instr.OpCode.Code != Code.Ldvirtftn)
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continue;
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var handler = instr.Operand as MethodDefinition;
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if (handler == null)
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continue;
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if (!DotNetUtils.isMethod(handler, "System.Reflection.Assembly", "(System.Object,System.ResolveEventArgs)"))
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continue;
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list.Add(handler);
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}
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return list;
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}
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public static MethodDefinition getResolveMethod(MethodDefinition method) {
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var handlers = DeobUtils.getAllResolveHandlers(method);
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if (handlers.Count == 0)
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return null;
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return handlers[0];
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}
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}
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}
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