106 lines
3.0 KiB
C#
106 lines
3.0 KiB
C#
/*
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Copyright (C) 2011 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 Mono.Cecil;
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using de4dot.blocks;
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namespace de4dot.deobfuscators.dotNET_Reactor {
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class MethodsDecrypter {
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ModuleDefinition module;
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MethodDefinition methodsDecrypterMethod;
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public bool Detected {
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get { return methodsDecrypterMethod != null; }
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}
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public MethodsDecrypter(ModuleDefinition module) {
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this.module = module;
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}
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public void find() {
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var checkedMethods = new Dictionary<MethodReferenceAndDeclaringTypeKey, bool>();
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var callCounter = new CallCounter();
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int typesLeft = 30;
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foreach (var type in module.GetTypes()) {
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if (typesLeft-- <= 0)
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break;
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var cctor = DotNetUtils.getMethod(type, ".cctor");
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if (cctor == null || cctor.Body == null)
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continue;
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foreach (var info in DotNetUtils.getCalledMethods(module, cctor)) {
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var method = info.Item2;
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var key = new MethodReferenceAndDeclaringTypeKey(method);
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if (!checkedMethods.ContainsKey(key)) {
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checkedMethods[key] = true;
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if (!couldBeMethodsDecrypter(method))
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continue;
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}
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callCounter.add(method);
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}
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}
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methodsDecrypterMethod = (MethodDefinition)callCounter.most();
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}
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bool couldBeMethodsDecrypter(MethodDefinition method) {
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if (!method.IsStatic)
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return false;
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if (method.Body == null)
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return false;
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if (method.Body.Instructions.Count < 2000)
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return false;
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var localTypes = new Dictionary<string, bool>(StringComparer.Ordinal);
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foreach (var local in method.Body.Variables)
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localTypes[local.VariableType.FullName] = true;
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var requiredTypes = new string[] {
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"System.Byte[]",
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"System.Diagnostics.StackFrame",
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"System.IntPtr",
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"System.IO.BinaryReader",
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"System.IO.MemoryStream",
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"System.Reflection.Assembly",
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"System.Security.Cryptography.CryptoStream",
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"System.Security.Cryptography.ICryptoTransform",
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"System.Security.Cryptography.RijndaelManaged",
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};
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foreach (var typeName in requiredTypes) {
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if (!localTypes.ContainsKey(typeName))
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return false;
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}
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if (!isResourceString(DotNetUtils.getCodeStrings(method)))
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return false;
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return true;
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}
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bool isResourceString(IList<string> strings) {
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foreach (var s in strings) {
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if (DotNetUtils.getResource(module, s) != null)
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return true;
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}
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return false;
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}
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}
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}
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