128 lines
3.6 KiB
C#
128 lines
3.6 KiB
C#
/*
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Copyright (C) 2011-2015 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 dnlib.DotNet;
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using dnlib.DotNet.Emit;
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using de4dot.blocks;
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namespace de4dot.code.deobfuscators.Goliath_NET {
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class StrongNameChecker {
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ModuleDefMD module;
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TypeDef strongNameType;
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MethodDef strongNameCheckMethod;
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public bool Detected {
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get { return strongNameType != null; }
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}
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public TypeDef Type {
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get { return strongNameType; }
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}
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public MethodDef CheckerMethod {
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get { return strongNameCheckMethod; }
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}
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public StrongNameChecker(ModuleDefMD module) {
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this.module = module;
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}
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public void Find() {
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foreach (var type in module.Types) {
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if (type.HasFields || type.HasEvents || type.HasProperties)
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continue;
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var checkMethod = GetAntiTamperingDetectionMethod(type);
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if (checkMethod == null)
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continue;
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if (DotNetUtils.GetMethod(type, "System.Byte[]", "(System.Reflection.Assembly)") == null)
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continue;
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if (DotNetUtils.GetMethod(type, "System.String", "(System.Collections.Generic.Stack`1<System.Int32>)") == null)
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continue;
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if (DotNetUtils.GetMethod(type, "System.Int32", "(System.Int32,System.Byte[])") == null)
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continue;
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strongNameType = type;
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strongNameCheckMethod = checkMethod;
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return;
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}
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}
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MethodDef GetAntiTamperingDetectionMethod(TypeDef type) {
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var requiredLocals = new string[] {
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"System.Reflection.Assembly",
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"System.Collections.Generic.Stack`1<System.Int32>",
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};
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foreach (var method in type.Methods) {
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if (!method.IsStatic || method.Body == null)
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continue;
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if (!DotNetUtils.IsMethod(method, "System.Void", "(System.Type)"))
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continue;
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if (!new LocalTypes(method).All(requiredLocals))
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continue;
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if (!HasThrow(method))
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continue;
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return method;
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}
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return null;
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}
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static bool HasThrow(MethodDef method) {
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if (method == null || method.Body == null)
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return false;
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foreach (var instr in method.Body.Instructions) {
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if (instr.OpCode.Code == Code.Throw)
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return true;
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}
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return false;
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}
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public bool Deobfuscate(Blocks blocks) {
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if (blocks.Method.Name != ".cctor" && blocks.Method.Name != ".ctor")
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return false;
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foreach (var block in blocks.MethodBlocks.GetAllBlocks()) {
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var instrs = block.Instructions;
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for (int i = 0; i < instrs.Count - 2; i++) {
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var ldtoken = instrs[i];
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if (ldtoken.OpCode.Code != Code.Ldtoken)
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continue;
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var call1 = instrs[i + 1];
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if (call1.OpCode.Code != Code.Call && call1.OpCode.Code != Code.Callvirt)
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continue;
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if (!DotNetUtils.IsMethod(call1.Operand as IMethod, "System.Type", "(System.RuntimeTypeHandle)"))
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continue;
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var call2 = instrs[i + 2];
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if (call2.OpCode.Code != Code.Call && call2.OpCode.Code != Code.Callvirt)
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continue;
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if (!MethodEqualityComparer.CompareDeclaringTypes.Equals(call2.Operand as IMethod, strongNameCheckMethod))
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continue;
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block.Remove(i, 3);
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return true;
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}
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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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