/*
Copyright (C) 2011-2012 de4dot@gmail.com
This file is part of de4dot.
de4dot is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
de4dot is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with de4dot. If not, see .
*/
using System;
using System.Collections.Generic;
using Mono.Cecil;
using Mono.Cecil.Cil;
using de4dot.blocks;
namespace de4dot.code.deobfuscators.CodeFort {
class ProxyCallFixer : ProxyCallFixer3 {
IList memberReferences;
MethodDefinitionAndDeclaringTypeDict proxyTargetMethods = new MethodDefinitionAndDeclaringTypeDict();
TypeDefinition proxyMethodsType;
public TypeDefinition ProxyMethodsType {
get { return proxyMethodsType; }
}
public ProxyCallFixer(ModuleDefinition module)
: base(module) {
}
public bool isProxyTargetMethod(MethodReference method) {
return proxyTargetMethods.find(method);
}
public void findDelegateCreator() {
foreach (var type in module.Types) {
var creatorMethod = checkType(type);
if (creatorMethod == null)
continue;
setDelegateCreatorMethod(creatorMethod);
return;
}
}
static MethodDefinition checkType(TypeDefinition type) {
if (type.Fields.Count != 1)
return null;
if (type.Fields[0].FieldType.FullName != "System.Reflection.Module")
return null;
return checkMethods(type);
}
static MethodDefinition checkMethods(TypeDefinition type) {
if (type.Methods.Count != 3)
return null;
MethodDefinition creatorMethod = null;
foreach (var method in type.Methods) {
if (method.Name == ".cctor")
continue;
if (DotNetUtils.isMethod(method, "System.Void", "(System.Int32)")) {
creatorMethod = method;
continue;
}
if (DotNetUtils.isMethod(method, "System.MulticastDelegate", "(System.Type,System.Reflection.MethodInfo,System.Int32)"))
continue;
return null;
}
return creatorMethod;
}
protected override object checkCctor(TypeDefinition type, MethodDefinition cctor) {
var instrs = cctor.Body.Instructions;
if (instrs.Count != 3)
return null;
var ldci4 = instrs[0];
if (!DotNetUtils.isLdcI4(ldci4))
return null;
var call = instrs[1];
if (call.OpCode.Code != Code.Call)
return null;
if (!isDelegateCreatorMethod(call.Operand as MethodDefinition))
return null;
int rid = DotNetUtils.getLdcI4Value(ldci4);
if (cctor.DeclaringType.MetadataToken.RID != rid)
throw new ApplicationException("Invalid rid");
return rid;
}
protected override void getCallInfo(object context, FieldDefinition field, out MethodReference calledMethod, out OpCode callOpcode) {
if (memberReferences == null)
memberReferences = new List(module.GetMemberReferences());
int rid = 0;
foreach (var c in field.Name)
rid = (rid << 4) + hexToInt((char)((byte)c + 0x2F));
rid &= 0x00FFFFFF;
calledMethod = (MethodReference)memberReferences[rid - 1];
var calledMethodDef = DotNetUtils.getMethod(module, calledMethod);
if (calledMethodDef != null) {
proxyMethodsType = calledMethodDef.DeclaringType;
proxyTargetMethods.add(calledMethodDef, true);
calledMethod = calledMethodDef;
}
callOpcode = OpCodes.Call;
}
static int hexToInt(char c) {
if ('0' <= c && c <= '9')
return c - '0';
if ('a' <= c && c <= 'f')
return c - 'a' + 10;
if ('A' <= c && c <= 'F')
return c - 'A' + 10;
throw new ApplicationException("Invalid hex digit");
}
}
}