126 lines
3.6 KiB
C#
126 lines
3.6 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.CodeFort {
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class ProxyCallFixer : ProxyCallFixer3 {
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MethodDefAndDeclaringTypeDict<bool> proxyTargetMethods = new MethodDefAndDeclaringTypeDict<bool>();
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TypeDef proxyMethodsType;
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public TypeDef ProxyMethodsType {
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get { return proxyMethodsType; }
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}
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public ProxyCallFixer(ModuleDefMD module)
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: base(module) {
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}
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public bool IsProxyTargetMethod(IMethod method) {
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return proxyTargetMethods.Find(method);
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}
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public void FindDelegateCreator() {
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foreach (var type in module.Types) {
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var creatorMethod = CheckType(type);
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if (creatorMethod == null)
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continue;
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SetDelegateCreatorMethod(creatorMethod);
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return;
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}
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}
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static MethodDef CheckType(TypeDef type) {
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if (type.Fields.Count != 1)
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return null;
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if (type.Fields[0].FieldSig.GetFieldType().GetFullName() != "System.Reflection.Module")
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return null;
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return CheckMethods(type);
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}
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static MethodDef CheckMethods(TypeDef type) {
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if (type.Methods.Count != 3)
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return null;
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MethodDef creatorMethod = null;
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foreach (var method in type.Methods) {
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if (method.Name == ".cctor")
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continue;
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if (DotNetUtils.IsMethod(method, "System.Void", "(System.Int32)")) {
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creatorMethod = method;
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continue;
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}
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if (DotNetUtils.IsMethod(method, "System.MulticastDelegate", "(System.Type,System.Reflection.MethodInfo,System.Int32)"))
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continue;
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return null;
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}
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return creatorMethod;
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}
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protected override object CheckCctor(ref TypeDef type, MethodDef cctor) {
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var instrs = cctor.Body.Instructions;
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if (instrs.Count != 3)
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return null;
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var ldci4 = instrs[0];
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if (!ldci4.IsLdcI4())
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return null;
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var call = instrs[1];
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if (call.OpCode.Code != Code.Call)
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return null;
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if (!IsDelegateCreatorMethod(call.Operand as MethodDef))
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return null;
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int rid = ldci4.GetLdcI4Value();
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if (cctor.DeclaringType.Rid != rid)
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throw new ApplicationException("Invalid rid");
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return rid;
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}
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protected override void GetCallInfo(object context, FieldDef field, out IMethod calledMethod, out OpCode callOpcode) {
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uint rid = 0;
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foreach (var c in field.Name.String)
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rid = (rid << 4) + (uint)HexToInt((char)((byte)c + 0x2F));
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rid &= 0x00FFFFFF;
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calledMethod = module.ResolveMemberRef(rid);
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var calledMethodDef = DotNetUtils.GetMethod2(module, calledMethod);
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if (calledMethodDef != null) {
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proxyMethodsType = calledMethodDef.DeclaringType;
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proxyTargetMethods.Add(calledMethodDef, true);
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calledMethod = calledMethodDef;
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}
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callOpcode = OpCodes.Call;
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}
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static int HexToInt(char c) {
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if ('0' <= c && c <= '9')
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return c - '0';
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if ('a' <= c && c <= 'f')
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return c - 'a' + 10;
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if ('A' <= c && c <= 'F')
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return c - 'A' + 10;
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throw new ApplicationException("Invalid hex digit");
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}
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}
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}
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