234 lines
6.5 KiB
C#
234 lines
6.5 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 dot10.DotNet;
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using de4dot.blocks;
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namespace de4dot.code.deobfuscators.Agile_NET {
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class CliSecureRtType {
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ModuleDefMD module;
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TypeDef cliSecureRtType;
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MethodDef postInitializeMethod;
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MethodDef initializeMethod;
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MethodDef stringDecrypterMethod;
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MethodDef loadMethod;
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bool foundSig;
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public bool Detected {
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get { return foundSig || cliSecureRtType != null; }
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}
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public TypeDef Type {
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get { return cliSecureRtType; }
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}
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public MethodDef StringDecrypterMethod {
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get { return stringDecrypterMethod; }
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}
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public MethodDef PostInitializeMethod {
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get { return postInitializeMethod; }
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}
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public MethodDef InitializeMethod {
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get { return initializeMethod; }
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}
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public MethodDef LoadMethod {
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get { return loadMethod; }
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}
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public CliSecureRtType(ModuleDefMD module) {
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this.module = module;
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}
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public CliSecureRtType(ModuleDefMD module, CliSecureRtType oldOne) {
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this.module = module;
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cliSecureRtType = lookup(oldOne.cliSecureRtType, "Could not find CliSecureRt type");
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postInitializeMethod = lookup(oldOne.postInitializeMethod, "Could not find postInitializeMethod method");
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initializeMethod = lookup(oldOne.initializeMethod, "Could not find initializeMethod method");
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stringDecrypterMethod = lookup(oldOne.stringDecrypterMethod, "Could not find stringDecrypterMethod method");
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loadMethod = lookup(oldOne.loadMethod, "Could not find loadMethod method");
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foundSig = oldOne.foundSig;
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}
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T lookup<T>(T def, string errorMessage) where T : class, ICodedToken {
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return DeobUtils.lookup(module, def, errorMessage);
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}
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public void find(byte[] moduleBytes) {
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if (cliSecureRtType != null)
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return;
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if (find2())
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return;
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if (find3())
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return;
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findNativeCode(moduleBytes);
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}
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static readonly string[] requiredFields1 = new string[] {
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"System.Boolean",
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};
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static readonly string[] requiredFields2 = new string[] {
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"System.Boolean",
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"System.Reflection.Assembly",
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};
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static readonly string[] requiredFields3 = new string[] {
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"System.Boolean",
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"System.Byte[]",
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};
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static readonly string[] requiredFields4 = new string[] {
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"System.Boolean",
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"System.Reflection.Assembly",
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"System.Byte[]",
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};
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bool find2() {
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foreach (var cctor in DeobUtils.getInitCctors(module, 3)) {
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foreach (var calledMethod in DotNetUtils.getCalledMethods(module, cctor)) {
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var type = calledMethod.DeclaringType;
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if (type.IsPublic)
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continue;
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var fieldTypes = new FieldTypes(type);
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if (!fieldTypes.exactly(requiredFields1) && !fieldTypes.exactly(requiredFields2) &&
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!fieldTypes.exactly(requiredFields3) && !fieldTypes.exactly(requiredFields4))
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continue;
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if (!hasInitializeMethod(type, "_Initialize") && !hasInitializeMethod(type, "_Initialize64"))
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continue;
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stringDecrypterMethod = findStringDecrypterMethod(type);
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initializeMethod = calledMethod;
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postInitializeMethod = findMethod(type, "System.Void", "PostInitialize", "()");
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loadMethod = findMethod(type, "System.IntPtr", "Load", "()");
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cliSecureRtType = type;
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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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bool find3() {
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foreach (var type in module.Types) {
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if (type.Fields.Count != 1)
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continue;
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if (type.Fields[0].FieldSig.GetFieldType().GetFullName() != "System.Byte[]")
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continue;
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if (type.Methods.Count != 2)
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continue;
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if (type.FindStaticConstructor() == null)
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continue;
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var cs = type.FindMethod("cs");
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if (cs == null)
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continue;
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stringDecrypterMethod = cs;
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cliSecureRtType = type;
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return true;
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}
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return false;
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}
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static MethodDef findStringDecrypterMethod(TypeDef type) {
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foreach (var method in type.Methods) {
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if (method.Body == null || !method.IsStatic)
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continue;
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if (!DotNetUtils.isMethod(method, "System.String", "(System.String)"))
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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 MethodDef findMethod(TypeDef type, string returnType, string name, string parameters) {
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var methodName = returnType + " " + type.FullName + "::" + name + parameters;
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foreach (var method in type.Methods) {
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if (method.Body == null || !method.IsStatic)
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continue;
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if (method.FullName != methodName)
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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 hasInitializeMethod(TypeDef type, string name) {
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var method = DotNetUtils.getPInvokeMethod(type, name);
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if (method == null)
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return false;
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var sig = method.MethodSig;
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if (sig.Params.Count != 1)
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return false;
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if (sig.Params[0].GetElementType() != ElementType.I)
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return false;
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var retType = sig.RetType.GetElementType();
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if (retType != ElementType.Void && retType != ElementType.I4)
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return false;
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return true;
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}
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bool findNativeCode(byte[] moduleBytes) {
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var bytes = moduleBytes != null ? moduleBytes : DeobUtils.readModule(module);
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using (var peImage = new MyPEImage(bytes))
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return foundSig = MethodsDecrypter.detect(peImage);
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}
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public bool isAtLeastVersion50() {
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return DotNetUtils.hasPinvokeMethod(cliSecureRtType, "LoadLibraryA");
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}
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public void findStringDecrypterMethod() {
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if (cliSecureRtType != null)
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return;
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foreach (var type in module.Types) {
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if (type.Fields.Count != 0)
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continue;
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if (type.Methods.Count != 1)
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continue;
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var cs = type.Methods[0];
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if (!isOldStringDecrypterMethod(cs))
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continue;
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cliSecureRtType = type;
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stringDecrypterMethod = cs;
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return;
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}
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}
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static bool isOldStringDecrypterMethod(MethodDef method) {
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if (method == null || method.Body == null || !method.IsStatic)
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return false;
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if (!DotNetUtils.isMethod(method, "System.String", "(System.String)"))
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return false;
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if (!DeobUtils.hasInteger(method, 0xFF))
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return false;
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return true;
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}
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}
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}
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