399 lines
11 KiB
C#
399 lines
11 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 Mono.Cecil;
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using Mono.Cecil.Cil;
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using de4dot.blocks;
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namespace de4dot.code.deobfuscators.DeepSea {
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class ResourceResolver : ResolverBase {
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// V3
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EmbeddedResource resource;
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// V40
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FieldDefinition resourceField;
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MethodDefinition getDataMethod;
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int magicV4;
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// V41
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Data41 data41;
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ResourceVersion version = ResourceVersion.Unknown;
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enum ResourceVersion {
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Unknown,
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V3,
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V40,
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V41,
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}
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class Data41 {
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public FieldDefinition resourceField;
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public MethodDefinition resolveHandler2;
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public int magic;
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public bool isTrial;
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}
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class HandlerInfo {
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public MethodDefinition handler;
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public IList<object> args;
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public HandlerInfo(MethodDefinition handler, IList<object> args) {
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this.handler = handler;
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this.args = args;
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}
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}
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public MethodDefinition GetDataMethod {
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get { return getDataMethod; }
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}
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public EmbeddedResource Resource {
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get { return resource; }
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}
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public ResourceResolver(ModuleDefinition module, ISimpleDeobfuscator simpleDeobfuscator, IDeobfuscator deob)
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: base(module, simpleDeobfuscator, deob) {
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}
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protected override bool checkResolverInitMethodInternal(MethodDefinition resolverInitMethod) {
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return DotNetUtils.callsMethod(resolverInitMethod, "System.Void System.AppDomain::add_ResourceResolve(System.ResolveEventHandler)");
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}
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protected override bool checkHandlerMethodDesktopInternal(MethodDefinition handler) {
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if (checkHandlerV3(handler)) {
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version = ResourceVersion.V3;
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return true;
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}
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FieldDefinition resourceFieldTmp;
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MethodDefinition getDataMethodTmp;
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simpleDeobfuscator.deobfuscate(handler);
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if (checkHandlerV40(handler, out resourceFieldTmp, out getDataMethodTmp, out magicV4)) {
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version = ResourceVersion.V40;
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resourceField = resourceFieldTmp;
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getDataMethod = getDataMethodTmp;
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return true;
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}
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var info = getHandlerArgs41(handler);
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Data41 data41Tmp;
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if (info != null && checkHandlerV41(info, out data41Tmp)) {
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version = ResourceVersion.V41;
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data41 = data41Tmp;
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return true;
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}
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return false;
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}
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HandlerInfo getHandlerArgs41(MethodDefinition handler) {
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var instrs = handler.Body.Instructions;
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for (int i = 0; i < instrs.Count; i++) {
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var instr = instrs[i];
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if (instr.OpCode.Code != Code.Call)
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continue;
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var calledMethod = instr.Operand as MethodDefinition;
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if (calledMethod == null)
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continue;
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var args = getArgValues(DotNetUtils.getArgPushes(instrs, i));
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if (args == null)
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continue;
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return new HandlerInfo(calledMethod, args);
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}
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return null;
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}
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bool checkHandlerV41(HandlerInfo info, out Data41 data41) {
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data41 = new Data41();
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data41.resolveHandler2 = info.handler;
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data41.resourceField = getLdtokenField(info.handler);
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if (data41.resourceField == null)
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return false;
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int magicArgIndex = getMagicArgIndex41Retail(info.handler);
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if (magicArgIndex < 0) {
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magicArgIndex = getMagicArgIndex41Trial(info.handler);
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data41.isTrial = true;
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}
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var asmVer = module.Assembly.Name.Version;
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if (magicArgIndex < 0 || magicArgIndex >= info.args.Count)
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return false;
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var val = info.args[magicArgIndex];
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if (!(val is int))
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return false;
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if (data41.isTrial)
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data41.magic = (int)val >> 3;
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else
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data41.magic = ((asmVer.Major << 3) | (asmVer.Minor << 2) | asmVer.Revision) - (int)val;
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return true;
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}
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static int getMagicArgIndex41Retail(MethodDefinition method) {
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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 add = instrs[i];
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if (add.OpCode.Code != Code.Add)
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continue;
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var ldarg = instrs[i + 1];
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if (!DotNetUtils.isLdarg(ldarg))
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continue;
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var sub = instrs[i + 2];
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if (sub.OpCode.Code != Code.Sub)
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continue;
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var ldci4 = instrs[i + 3];
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if (!DotNetUtils.isLdcI4(ldci4) || DotNetUtils.getLdcI4Value(ldci4) != 0xFF)
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continue;
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return DotNetUtils.getArgIndex(ldarg);
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}
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return -1;
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}
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static int getMagicArgIndex41Trial(MethodDefinition method) {
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var instrs = method.Body.Instructions;
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for (int i = 0; i < instrs.Count - 2; i++) {
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var ldarg = instrs[i];
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if (!DotNetUtils.isLdarg(ldarg))
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continue;
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if (!DotNetUtils.isLdcI4(instrs[i + 1]))
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continue;
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if (instrs[i + 2].OpCode.Code != Code.Shr)
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continue;
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return DotNetUtils.getArgIndex(ldarg);
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}
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return -1;
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}
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static FieldDefinition getLdtokenField(MethodDefinition method) {
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foreach (var instr in method.Body.Instructions) {
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if (instr.OpCode.Code != Code.Ldtoken)
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continue;
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var field = instr.Operand as FieldDefinition;
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if (field == null || field.InitialValue == null || field.InitialValue.Length == 0)
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continue;
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return field;
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}
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return null;
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}
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static IList<object> getArgValues(IList<Instruction> argInstrs) {
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if (argInstrs == null)
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return null;
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var args = new List<object>(argInstrs.Count);
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foreach (var argInstr in argInstrs) {
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object arg;
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getArgValue(argInstr, out arg);
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args.Add(arg);
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}
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return args;
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}
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static bool getArgValue(MethodDefinition method, int index, out object arg) {
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return getArgValue(method.Body.Instructions[index], out arg);
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}
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static bool getArgValue(Instruction instr, out object arg) {
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switch (instr.OpCode.Code) {
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case Code.Ldc_I4_S: arg = (int)(sbyte)instr.Operand; return true;
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case Code.Ldc_I4_M1: arg = -1; return true;
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case Code.Ldc_I4_0: arg = 0; return true;
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case Code.Ldc_I4_1: arg = 1; return true;
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case Code.Ldc_I4_2: arg = 2; return true;
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case Code.Ldc_I4_3: arg = 3; return true;
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case Code.Ldc_I4_4: arg = 4; return true;
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case Code.Ldc_I4_5: arg = 5; return true;
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case Code.Ldc_I4_6: arg = 6; return true;
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case Code.Ldc_I4_7: arg = 7; return true;
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case Code.Ldc_I4_8: arg = 8; return true;
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case Code.Ldnull: arg = null; return true;
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case Code.Ldstr:
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case Code.Ldc_I4:
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case Code.Ldc_I8:
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case Code.Ldc_R4:
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case Code.Ldc_R8:
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arg = instr.Operand;
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return true;
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case Code.Ldarg:
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case Code.Ldarg_S:
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case Code.Ldarg_0:
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case Code.Ldarg_1:
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case Code.Ldarg_2:
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case Code.Ldarg_3:
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case Code.Ldloc:
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case Code.Ldloc_S:
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case Code.Ldloc_0:
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case Code.Ldloc_1:
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case Code.Ldloc_2:
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case Code.Ldloc_3:
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arg = null;
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return true;
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default:
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arg = null;
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return false;
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}
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}
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static string[] handlerLocalTypes_V3 = new string[] {
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"System.AppDomain",
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"System.Byte[]",
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"System.Collections.Generic.Dictionary`2<System.String,System.String>",
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"System.IO.Compression.DeflateStream",
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"System.IO.MemoryStream",
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"System.IO.Stream",
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"System.Reflection.Assembly",
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"System.String",
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"System.String[]",
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};
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static bool checkHandlerV3(MethodDefinition handler) {
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return new LocalTypes(handler).all(handlerLocalTypes_V3);
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}
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static bool checkHandlerV40(MethodDefinition handler, out FieldDefinition resourceField, out MethodDefinition getDataMethod, out int magic) {
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var instrs = handler.Body.Instructions;
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for (int i = 0; i < instrs.Count; i++) {
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int index = i;
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if (instrs[index++].OpCode.Code != Code.Ldarg_1)
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continue;
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var ldtoken = instrs[index++];
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if (ldtoken.OpCode.Code != Code.Ldtoken)
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continue;
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var field = ldtoken.Operand as FieldDefinition;
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string methodSig = "(System.ResolveEventArgs,System.RuntimeFieldHandle,System.Int32,System.String,System.Int32)";
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var method = ldtoken.Operand as MethodDefinition;
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if (method != null) {
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// >= 4.0.4
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if (!DotNetUtils.isMethod(method, "System.Byte[]", "()"))
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continue;
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field = getResourceField(method);
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methodSig = "(System.ResolveEventArgs,System.RuntimeMethodHandle,System.Int32,System.String,System.Int32)";
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}
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else {
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// 4.0.1.18 .. 4.0.3
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}
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if (field == null || field.InitialValue == null || field.InitialValue.Length == 0)
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continue;
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var ldci4_len = instrs[index++];
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if (!DotNetUtils.isLdcI4(ldci4_len))
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continue;
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if (DotNetUtils.getLdcI4Value(ldci4_len) != field.InitialValue.Length)
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continue;
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if (instrs[index++].OpCode.Code != Code.Ldstr)
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continue;
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var ldci4_magic = instrs[index++];
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if (!DotNetUtils.isLdcI4(ldci4_magic))
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continue;
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magic = DotNetUtils.getLdcI4Value(ldci4_magic);
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var call = instrs[index++];
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if (call.OpCode.Code == Code.Tail)
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call = instrs[index++];
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if (call.OpCode.Code != Code.Call)
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continue;
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if (!DotNetUtils.isMethod(call.Operand as MethodReference, "System.Reflection.Assembly", methodSig))
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continue;
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resourceField = field;
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getDataMethod = method;
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return true;
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}
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magic = 0;
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resourceField = null;
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getDataMethod = null;
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return false;
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}
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static FieldDefinition getResourceField(MethodDefinition method) {
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foreach (var instr in method.Body.Instructions) {
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if (instr.OpCode.Code != Code.Ldtoken)
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continue;
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var field = instr.Operand as FieldDefinition;
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if (field == null || field.InitialValue == null || field.InitialValue.Length == 0)
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continue;
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return field;
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}
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return null;
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}
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public void initialize() {
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if (resolveHandler == null)
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return;
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if (version == ResourceVersion.V3) {
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simpleDeobfuscator.deobfuscate(resolveHandler);
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simpleDeobfuscator.decryptStrings(resolveHandler, deob);
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resource = DeobUtils.getEmbeddedResourceFromCodeStrings(module, resolveHandler);
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if (resource == null) {
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Log.w("Could not find resource of encrypted resources");
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return;
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}
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}
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}
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public bool mergeResources(out EmbeddedResource rsrc) {
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rsrc = null;
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switch (version) {
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case ResourceVersion.V3:
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if (resource == null)
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return false;
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DeobUtils.decryptAndAddResources(module, resource.Name, () => decryptResourceV3(resource));
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rsrc = resource;
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return true;
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case ResourceVersion.V40:
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return decryptResource(resourceField, magicV4);
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case ResourceVersion.V41:
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return decryptResource(data41.resourceField, data41.magic);
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default:
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return true;
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}
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}
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bool decryptResource(FieldDefinition resourceField, int magic) {
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if (resourceField == null)
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return false;
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string name = string.Format("Embedded data field {0:X8} RVA {1:X8}", resourceField.MetadataToken.ToInt32(), resourceField.RVA);
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DeobUtils.decryptAndAddResources(module, name, () => decryptResourceV4(resourceField.InitialValue, magic));
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resourceField.InitialValue = new byte[1];
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resourceField.FieldType = module.TypeSystem.Byte;
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return true;
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}
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}
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}
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