/* Copyright (C) 2011-2013 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 dnlib.IO; using dnlib.DotNet; using dnlib.DotNet.Emit; using de4dot.blocks; namespace de4dot.code.deobfuscators.Confuser { static class ConfuserUtils { public static int findCallMethod(IList instrs, int index, Code callCode, string methodFullName) { for (int i = index; i < instrs.Count; i++) { if (!isCallMethod(instrs[i], callCode, methodFullName)) continue; return i; } return -1; } public static int findCallMethod(IList instrs, int index, Code callCode, string methodFullName) { for (int i = index; i < instrs.Count; i++) { if (!isCallMethod(instrs[i].Instruction, callCode, methodFullName)) continue; return i; } return -1; } public static bool isCallMethod(Instruction instr, Code callCode, string methodFullName) { if (instr.OpCode.Code != callCode) return false; var calledMethod = instr.Operand as IMethod; return calledMethod != null && calledMethod.FullName == methodFullName; } public static bool removeResourceHookCode(Blocks blocks, MethodDef handler) { return removeResolveHandlerCode(blocks, handler, "System.Void System.AppDomain::add_ResourceResolve(System.ResolveEventHandler)"); } public static bool removeAssemblyHookCode(Blocks blocks, MethodDef handler) { return removeResolveHandlerCode(blocks, handler, "System.Void System.AppDomain::add_AssemblyResolve(System.ResolveEventHandler)"); } static bool removeResolveHandlerCode(Blocks blocks, MethodDef handler, string installHandlerMethod) { bool modified = false; foreach (var block in blocks.MethodBlocks.getAllBlocks()) { var instrs = block.Instructions; for (int i = 0; i < instrs.Count - 4; i++) { var call = instrs[i]; if (call.OpCode.Code != Code.Call) continue; var calledMethod = call.Operand as IMethod; if (calledMethod == null || calledMethod.FullName != "System.AppDomain System.AppDomain::get_CurrentDomain()") continue; if (instrs[i + 1].OpCode.Code != Code.Ldnull) continue; var ldftn = instrs[i + 2]; if (ldftn.OpCode.Code != Code.Ldftn) continue; if (ldftn.Operand != handler) continue; var newobj = instrs[i + 3]; if (newobj.OpCode.Code != Code.Newobj) continue; var ctor = newobj.Operand as IMethod; if (ctor == null || ctor.FullName != "System.Void System.ResolveEventHandler::.ctor(System.Object,System.IntPtr)") continue; var callvirt = instrs[i + 4]; if (callvirt.OpCode.Code != Code.Callvirt) continue; calledMethod = callvirt.Operand as IMethod; if (calledMethod == null || calledMethod.FullName != installHandlerMethod) continue; block.remove(i, 5); modified = true; } } return modified; } public static byte[] decryptCompressedInt32Data(Arg64ConstantsReader constReader, int exprStart, int exprEnd, IBinaryReader reader, byte[] decrypted) { for (int i = 0; i < decrypted.Length; i++) { constReader.Arg = reader.Read7BitEncodedInt32(); int index = exprStart; long result; if (!constReader.getInt64(ref index, out result) || index != exprEnd) throw new ApplicationException("Could not decrypt integer"); decrypted[i] = (byte)result; } return decrypted; } static readonly byte[] defaultDecryptKey = new byte[1]; public static byte[] decrypt(uint seed, byte[] encrypted) { return decrypt(seed, encrypted, defaultDecryptKey); } public static byte[] decrypt(uint seed, byte[] encrypted, byte[] key) { var decrypted = new byte[encrypted.Length]; ushort _m = (ushort)(seed >> 16); ushort _c = (ushort)seed; ushort m = _c; ushort c = _m; for (int i = 0; i < decrypted.Length; i++) { decrypted[i] = (byte)(encrypted[i] ^ (seed * m + c) ^ key[i % key.Length]); m = (ushort)(seed * m + _m); c = (ushort)(seed * c + _c); } return decrypted; } public static int countCalls(MethodDef method, string methodFullName) { if (method == null || method.Body == null) return 0; int count = 0; foreach (var instr in method.Body.Instructions) { if (instr.OpCode.Code != Code.Call && instr.OpCode.Code != Code.Callvirt && instr.OpCode.Code != Code.Newobj) continue; var calledMethod = instr.Operand as IMethod; if (calledMethod != null && calledMethod.FullName == methodFullName) count++; } return count; } public static int countCalls(MethodDef method, MethodDef calledMethod) { if (method == null || method.Body == null) return 0; int count = 0; foreach (var instr in method.Body.Instructions) { if (instr.OpCode.Code != Code.Call && instr.OpCode.Code != Code.Callvirt && instr.OpCode.Code != Code.Newobj) continue; if (instr.Operand == calledMethod) count++; } return count; } public static int countOpCode(MethodDef method, Code code) { if (method == null || method.Body == null) return 0; int count = 0; foreach (var instr in method.Body.Instructions) { if (instr.OpCode.Code == code) count++; } return count; } } }