106 lines
3.2 KiB
C#
106 lines
3.2 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 Mono.Cecil;
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using Mono.Cecil.Cil;
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using de4dot.blocks;
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namespace de4dot.deobfuscators.dotNET_Reactor {
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// Find the class that returns a RuntimeTypeHandle/RuntimeFieldHandle. The value passed to
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// its methods is the original metadata token, which will be different when we save the file.
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class MetadataTokenObfuscator {
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ModuleDefinition module;
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TypeDefinition type;
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MethodDefinition typeMethod;
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MethodDefinition fieldMethod;
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public TypeDefinition Type {
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get { return type; }
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}
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public MetadataTokenObfuscator(ModuleDefinition module) {
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this.module = module;
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find();
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}
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void find() {
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foreach (var type in module.Types) {
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var fields = type.Fields;
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if (fields.Count != 1)
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continue;
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if (fields[0].FieldType.FullName != "System.ModuleHandle")
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continue;
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if (type.HasProperties || type.HasEvents)
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continue;
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MethodDefinition fieldMethod = null, typeMethod = null;
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foreach (var method in type.Methods) {
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if (method.Parameters.Count != 1)
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continue;
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if (method.Parameters[0].ParameterType.FullName != "System.Int32")
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continue;
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if (method.MethodReturnType.ReturnType.FullName == "System.RuntimeTypeHandle")
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typeMethod = method;
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else if (method.MethodReturnType.ReturnType.FullName == "System.RuntimeFieldHandle")
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fieldMethod = method;
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}
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if (typeMethod == null || fieldMethod == null)
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continue;
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this.type = type;
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this.typeMethod = typeMethod;
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this.fieldMethod = fieldMethod;
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return;
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}
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}
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public void deobfuscate(Blocks blocks) {
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if (type == null)
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return;
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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 - 1; i++) {
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var instr = instrs[i];
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if (instr.OpCode.Code != Code.Ldc_I4)
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continue;
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var call = instrs[i + 1];
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if (call.OpCode.Code != Code.Call)
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continue;
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var method = call.Operand as MethodReference;
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if (method == null)
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continue;
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if (!MemberReferenceHelper.compareTypes(type, method.DeclaringType))
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continue;
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var methodDef = DotNetUtils.getMethod(module, method);
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if (methodDef == null)
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continue;
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if (methodDef != typeMethod && methodDef != fieldMethod)
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continue;
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int token = (int)instrs[i].Operand;
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instrs[i] = new Instr(Instruction.Create(OpCodes.Nop));
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instrs[i + 1] = new Instr(new Instruction(OpCodes.Ldtoken, module.LookupToken(token) as MemberReference));
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}
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}
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}
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}
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}
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