122 lines
3.4 KiB
C#
122 lines
3.4 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 ICSharpCode.SharpZipLib.Zip.Compression;
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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.Babel_NET {
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class InflaterCreator {
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public static Inflater Create(MethodDef method, bool noHeader) {
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return Create(FindInflaterType(method), noHeader);
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}
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public static Inflater Create(TypeDef inflaterType, bool noHeader) {
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if (inflaterType == null)
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return CreateNormal(noHeader);
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var initHeaderMethod = FindInitHeaderMethod(inflaterType);
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if (initHeaderMethod == null)
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return CreateNormal(noHeader, "Could not find inflater init header method");
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var magic = GetMagic(initHeaderMethod);
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if (!magic.HasValue)
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return CreateNormal(noHeader);
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return new BabelInflater(noHeader, magic.Value);
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}
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static Inflater CreateNormal(bool noHeader) {
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return CreateNormal(noHeader, null);
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}
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static Inflater CreateNormal(bool noHeader, string errorMessage) {
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if (errorMessage != null)
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Logger.w("{0}", errorMessage);
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return new Inflater(noHeader);
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}
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static TypeDef FindInflaterType(MethodDef method) {
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if (method == null || method.Body == null)
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return null;
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foreach (var instr in method.Body.Instructions) {
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if (instr.OpCode.Code != Code.Call)
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continue;
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var calledMethod = instr.Operand as MethodDef;
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if (calledMethod == null || !calledMethod.IsStatic)
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continue;
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var type = calledMethod.DeclaringType;
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foreach (var nested in type.NestedTypes) {
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if (DeobUtils.HasInteger(nested.FindMethod(".ctor"), 0x8001))
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return type;
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}
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}
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return null;
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}
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static MethodDef FindInitHeaderMethod(TypeDef inflaterType) {
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foreach (var nested in inflaterType.NestedTypes) {
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var method = FindInitHeaderMethod2(nested);
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if (method != null)
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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 FindInitHeaderMethod2(TypeDef nested) {
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foreach (var method in nested.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.Boolean", "()"))
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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 int? GetMagic(MethodDef method) {
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if (method == null || method.Body == null)
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return null;
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var instrs = method.Body.Instructions;
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for (int i = 0; i < instrs.Count - 3; i++) {
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var ldci4_1 = instrs[i];
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if (!ldci4_1.IsLdcI4() || ldci4_1.GetLdcI4Value() != 16)
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continue;
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var callvirt = instrs[i + 1];
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if (callvirt.OpCode.Code != Code.Callvirt)
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continue;
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var ldci4_2 = instrs[i + 2];
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if (!ldci4_2.IsLdcI4())
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continue;
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if (instrs[i + 3].OpCode.Code != Code.Xor)
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continue;
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return ldci4_2.GetLdcI4Value();
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}
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return null;
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}
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}
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}
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