365 lines
9.9 KiB
C#
365 lines
9.9 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 System;
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using System.Collections.Generic;
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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.DeepSea {
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class ResourceResolver : ResolverBase {
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Data30 data30;
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Data40 data40;
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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 Data30 {
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public EmbeddedResource resource;
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}
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class Data40 {
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public FieldDef resourceField;
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public MethodDef resolveHandler2;
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public MethodDef getDataMethod;
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public int magic;
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}
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class Data41 {
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public FieldDef resourceField;
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public MethodDef 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 MethodDef handler;
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public IList<object> args;
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public HandlerInfo(MethodDef 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 MethodDef InitMethod2 {
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get {
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if (data40 != null)
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return data40.resolveHandler2;
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if (data41 != null)
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return data41.resolveHandler2;
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return null;
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}
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}
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public MethodDef GetDataMethod {
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get { return data40 != null ? data40.getDataMethod : null; }
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}
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public EmbeddedResource Resource {
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get { return data30 != null ? data30.resource : null; }
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}
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public ResourceResolver(ModuleDefMD 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(MethodDef 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(MethodDef 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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simpleDeobfuscator.Deobfuscate(handler);
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if ((data40 = CheckHandlerV40(handler)) != null) {
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version = ResourceVersion.V40;
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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(MethodDef 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 MethodDef;
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if (calledMethod == null)
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continue;
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if (GetLdtokenField(calledMethod) == null)
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continue;
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var args = DsUtils.GetArgValues(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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bool isOtherRetail;
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int magicArgIndex = GetMagicArgIndex41Retail(info.handler, out isOtherRetail);
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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.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 if (isOtherRetail)
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data41.magic = data41.resourceField.InitialValue.Length - (int)val;
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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(MethodDef method, out bool isOtherRetail) {
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isOtherRetail = false;
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var instrs = method.Body.Instructions;
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for (int i = 0; i < instrs.Count - 4; i++) {
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isOtherRetail = false;
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var ld = instrs[i];
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if (ld.IsLdarg())
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isOtherRetail = true;
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else if (!ld.IsLdloc())
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continue;
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var add = instrs[i + 1];
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if (add.OpCode.Code != Code.Add)
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continue;
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var ldarg = instrs[i + 2];
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if (!ldarg.IsLdarg())
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continue;
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var sub = instrs[i + 3];
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if (sub.OpCode.Code != Code.Sub)
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continue;
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var ldci4 = instrs[i + 4];
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if (!ldci4.IsLdcI4() || ldci4.GetLdcI4Value() != 0xFF)
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continue;
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return ldarg.GetParameterIndex();
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}
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return -1;
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}
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static int GetMagicArgIndex41Trial(MethodDef 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 (!ldarg.IsLdarg())
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continue;
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if (!instrs[i + 1].IsLdcI4())
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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 ldarg.GetParameterIndex();
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}
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return -1;
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}
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static FieldDef GetLdtokenField(MethodDef 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 FieldDef;
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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 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(MethodDef handler) {
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return new LocalTypes(handler).All(handlerLocalTypes_V3);
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}
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static Data40 CheckHandlerV40(MethodDef handler) {
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var data40 = new Data40();
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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 FieldDef;
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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 MethodDef;
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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 (!ldci4_len.IsLdcI4())
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continue;
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if (ldci4_len.GetLdcI4Value() != 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 (!ldci4_magic.IsLdcI4())
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continue;
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data40.magic = ldci4_magic.GetLdcI4Value();
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var call = instrs[index++];
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if (call.OpCode.Code == Code.Tailcall)
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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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var resolveHandler2 = call.Operand as MethodDef;
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if (!DotNetUtils.IsMethod(resolveHandler2, "System.Reflection.Assembly", methodSig))
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continue;
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data40.resourceField = field;
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data40.getDataMethod = method;
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data40.resolveHandler2 = resolveHandler2;
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return data40;
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}
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return null;
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}
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static FieldDef GetResourceField(MethodDef 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 FieldDef;
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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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data30 = new Data30();
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data30.resource = DeobUtils.GetEmbeddedResourceFromCodeStrings(module, resolveHandler);
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if (data30.resource == null) {
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Logger.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 (data30.resource == null)
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return false;
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DeobUtils.DecryptAndAddResources(module, data30.resource.Name.String, () => DecryptResourceV3(data30.resource));
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rsrc = data30.resource;
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return true;
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case ResourceVersion.V40:
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return DecryptResource(data40.resourceField, data40.magic);
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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(FieldDef 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.MDToken.ToInt32(), (uint)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.FieldSig.Type = module.CorLibTypes.Byte;
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resourceField.RVA = 0;
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return true;
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}
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}
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}
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