/*
Copyright (C) 2011-2013 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 System.IO;
using dnlib.DotNet;
using de4dot.blocks;
namespace de4dot.code.deobfuscators.Agile_NET {
class CliSecureRtType {
ModuleDefMD module;
TypeDef cliSecureRtType;
MethodDef postInitializeMethod;
MethodDef initializeMethod;
MethodDef stringDecrypterMethod;
MethodDef loadMethod;
bool foundSig;
public bool Detected {
get { return foundSig || cliSecureRtType != null; }
}
public TypeDef Type {
get { return cliSecureRtType; }
}
public MethodDef StringDecrypterMethod {
get { return stringDecrypterMethod; }
}
public MethodDef PostInitializeMethod {
get { return postInitializeMethod; }
}
public MethodDef InitializeMethod {
get { return initializeMethod; }
}
public MethodDef LoadMethod {
get { return loadMethod; }
}
public CliSecureRtType(ModuleDefMD module) {
this.module = module;
}
public CliSecureRtType(ModuleDefMD module, CliSecureRtType oldOne) {
this.module = module;
cliSecureRtType = Lookup(oldOne.cliSecureRtType, "Could not find CliSecureRt type");
postInitializeMethod = Lookup(oldOne.postInitializeMethod, "Could not find postInitializeMethod method");
initializeMethod = Lookup(oldOne.initializeMethod, "Could not find initializeMethod method");
stringDecrypterMethod = Lookup(oldOne.stringDecrypterMethod, "Could not find stringDecrypterMethod method");
loadMethod = Lookup(oldOne.loadMethod, "Could not find loadMethod method");
foundSig = oldOne.foundSig;
}
T Lookup(T def, string errorMessage) where T : class, ICodedToken {
return DeobUtils.Lookup(module, def, errorMessage);
}
public void Find(byte[] moduleBytes) {
if (cliSecureRtType != null)
return;
if (Find2())
return;
if (Find3())
return;
FindNativeCode(moduleBytes);
}
static readonly string[] requiredFields1 = new string[] {
"System.Boolean",
};
static readonly string[] requiredFields2 = new string[] {
"System.Boolean",
"System.Reflection.Assembly",
};
static readonly string[] requiredFields3 = new string[] {
"System.Boolean",
"System.Byte[]",
};
static readonly string[] requiredFields4 = new string[] {
"System.Boolean",
"System.Reflection.Assembly",
"System.Byte[]",
};
bool Find2() {
foreach (var cctor in DeobUtils.GetInitCctors(module, 3)) {
foreach (var calledMethod in DotNetUtils.GetCalledMethods(module, cctor)) {
var type = calledMethod.DeclaringType;
if (type.IsPublic)
continue;
var fieldTypes = new FieldTypes(type);
if (!fieldTypes.Exactly(requiredFields1) && !fieldTypes.Exactly(requiredFields2) &&
!fieldTypes.Exactly(requiredFields3) && !fieldTypes.Exactly(requiredFields4))
continue;
if (!HasInitializeMethod(type, "_Initialize") && !HasInitializeMethod(type, "_Initialize64"))
continue;
stringDecrypterMethod = FindStringDecrypterMethod(type);
initializeMethod = calledMethod;
postInitializeMethod = FindMethod(type, "System.Void", "PostInitialize", "()");
loadMethod = FindMethod(type, "System.IntPtr", "Load", "()");
cliSecureRtType = type;
return true;
}
}
return false;
}
bool Find3() {
foreach (var type in module.Types) {
if (type.Fields.Count != 1)
continue;
if (type.Fields[0].FieldSig.GetFieldType().GetFullName() != "System.Byte[]")
continue;
if (type.Methods.Count != 2)
continue;
if (type.FindStaticConstructor() == null)
continue;
var cs = type.FindMethod("cs");
if (cs == null)
continue;
stringDecrypterMethod = cs;
cliSecureRtType = type;
return true;
}
return false;
}
static MethodDef FindStringDecrypterMethod(TypeDef type) {
foreach (var method in type.Methods) {
if (method.Body == null || !method.IsStatic)
continue;
if (!DotNetUtils.IsMethod(method, "System.String", "(System.String)"))
continue;
return method;
}
return null;
}
static MethodDef FindMethod(TypeDef type, string returnType, string name, string parameters) {
var methodName = returnType + " " + type.FullName + "::" + name + parameters;
foreach (var method in type.Methods) {
if (method.Body == null || !method.IsStatic)
continue;
if (method.FullName != methodName)
continue;
return method;
}
return null;
}
static bool HasInitializeMethod(TypeDef type, string name) {
var method = DotNetUtils.GetPInvokeMethod(type, name);
if (method == null)
return false;
var sig = method.MethodSig;
if (sig.Params.Count != 1)
return false;
if (sig.Params[0].GetElementType() != ElementType.I)
return false;
var retType = sig.RetType.GetElementType();
if (retType != ElementType.Void && retType != ElementType.I4)
return false;
return true;
}
bool FindNativeCode(byte[] moduleBytes) {
var bytes = moduleBytes != null ? moduleBytes : DeobUtils.ReadModule(module);
using (var peImage = new MyPEImage(bytes))
return foundSig = MethodsDecrypter.Detect(peImage);
}
public bool IsAtLeastVersion50() {
return DotNetUtils.HasPinvokeMethod(cliSecureRtType, "LoadLibraryA");
}
public void FindStringDecrypterMethod() {
if (cliSecureRtType != null)
return;
foreach (var type in module.Types) {
if (type.Fields.Count != 0)
continue;
if (type.Methods.Count != 1)
continue;
var cs = type.Methods[0];
if (!IsOldStringDecrypterMethod(cs))
continue;
cliSecureRtType = type;
stringDecrypterMethod = cs;
return;
}
}
static bool IsOldStringDecrypterMethod(MethodDef method) {
if (method == null || method.Body == null || !method.IsStatic)
return false;
if (!DotNetUtils.IsMethod(method, "System.String", "(System.String)"))
return false;
if (!DeobUtils.HasInteger(method, 0xFF))
return false;
return true;
}
}
}