/*
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 System.IO;
using dot10.DotNet;
using de4dot.blocks;
using de4dot.PE;
namespace de4dot.code.deobfuscators.Agile_NET {
class CliSecureRtType {
ModuleDefinition 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 IEnumerable DecryptModuleReferences {
get {
var list = new List();
addModuleReference(list, "_Initialize");
addModuleReference(list, "_Initialize64");
return list;
}
}
void addModuleReference(List list, string methodName) {
var method = DotNetUtils.getPInvokeMethod(cliSecureRtType, methodName);
if (method == null)
return;
list.Add(method.PInvokeInfo.Module);
}
public CliSecureRtType(ModuleDefinition module) {
this.module = module;
}
public CliSecureRtType(ModuleDefinition 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 : MemberReference {
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].FieldType.FullName != "System.Byte[]")
continue;
if (type.Methods.Count != 2)
continue;
if (DotNetUtils.getMethod(type, ".cctor") == null)
continue;
var cs = DotNetUtils.getMethod(type, "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;
if (method.Parameters.Count != 1)
return false;
if (method.Parameters[0].ParameterType.FullName != "System.IntPtr")
return false;
var retType = method.MethodReturnType.ReturnType.FullName;
if (retType != "System.Void" && retType != "System.Int32")
return false;
return true;
}
bool findNativeCode(byte[] moduleBytes) {
var stream = moduleBytes != null ?
(Stream)new MemoryStream(moduleBytes) :
(Stream)new FileStream(module.FullyQualifiedName, FileMode.Open, FileAccess.Read, FileShare.Read);
using (stream) {
var peImage = new PeImage(stream);
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;
}
}
}