194 lines
6.1 KiB
C#
194 lines
6.1 KiB
C#
/*
|
|
Copyright (C) 2011 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 <http://www.gnu.org/licenses/>.
|
|
*/
|
|
|
|
using System.Collections.Generic;
|
|
using Mono.Cecil;
|
|
using Mono.Cecil.Cil;
|
|
using de4dot.blocks;
|
|
|
|
namespace de4dot.deobfuscators.SmartAssembly {
|
|
class StringsEncoderInfo {
|
|
// SmartAssembly.HouseOfCards.Strings, the class that creates the string decrypter
|
|
// delegates
|
|
public TypeDefinition StringsType { get; set; }
|
|
public TypeDefinition GetStringDelegate { get; set; }
|
|
public MethodDefinition CreateStringDelegateMethod { get; set; }
|
|
|
|
// The class that decodes the strings. Called by the strings delegate or normal code.
|
|
public TypeDefinition StringDecrypterClass { get; set; }
|
|
}
|
|
|
|
class StringEncoderClassFinder {
|
|
ModuleDefinition module;
|
|
ISimpleDeobfuscator simpleDeobfuscator;
|
|
IList<StringsEncoderInfo> stringsEncoderInfos = new List<StringsEncoderInfo>();
|
|
|
|
public IList<StringsEncoderInfo> StringsEncoderInfos {
|
|
get { return stringsEncoderInfos; }
|
|
}
|
|
|
|
public StringEncoderClassFinder(ModuleDefinition module, ISimpleDeobfuscator simpleDeobfuscator) {
|
|
this.module = module;
|
|
this.simpleDeobfuscator = simpleDeobfuscator;
|
|
}
|
|
|
|
TypeDefinition getType(TypeReference typeReference) {
|
|
return DotNetUtils.getType(module, typeReference);
|
|
}
|
|
|
|
public void find() {
|
|
findHouseOfCardsStrings_v2();
|
|
if (stringsEncoderInfos.Count == 0)
|
|
findHouseOfCardsStrings_v1();
|
|
|
|
findStringDecrypterClasses();
|
|
}
|
|
|
|
// Finds SmartAssembly.HouseOfCards.Strings. It's the class that creates the string
|
|
// decrypter delegates.
|
|
void findHouseOfCardsStrings_v2() {
|
|
foreach (var type in module.Types) {
|
|
if (type.Methods.Count != 1)
|
|
continue;
|
|
foreach (var method in DotNetUtils.findMethods(type.Methods, "System.Void", new string[] { "System.Type" })) {
|
|
if (checkDelegateCreatorMethod(type, method))
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
|
|
void findHouseOfCardsStrings_v1() {
|
|
foreach (var type in module.Types) {
|
|
if (type.Methods.Count != 1)
|
|
continue;
|
|
foreach (var method in DotNetUtils.findMethods(type.Methods, "System.Void", new string[] { })) {
|
|
if (checkDelegateCreatorMethod(type, method))
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
|
|
bool checkDelegateCreatorMethod(TypeDefinition type, MethodDefinition method) {
|
|
simpleDeobfuscator.deobfuscate(method);
|
|
|
|
var getStringDelegate = findGetStringDelegate(method);
|
|
if (getStringDelegate == null)
|
|
return false;
|
|
|
|
var stringDecrypterClass = findStringDecrypterClass(method);
|
|
if (stringDecrypterClass == null)
|
|
return false;
|
|
|
|
stringsEncoderInfos.Add(new StringsEncoderInfo {
|
|
StringsType = type,
|
|
GetStringDelegate = getStringDelegate,
|
|
StringDecrypterClass = stringDecrypterClass,
|
|
CreateStringDelegateMethod = method,
|
|
});
|
|
|
|
return true;
|
|
}
|
|
|
|
// Finds the SmartAssembly.Delegates.GetString delegate
|
|
TypeDefinition findGetStringDelegate(MethodDefinition stringsCreateDelegateMethod) {
|
|
if (!stringsCreateDelegateMethod.HasBody)
|
|
return null;
|
|
|
|
foreach (var ldtoken in stringsCreateDelegateMethod.Body.Instructions) {
|
|
if (ldtoken.OpCode.Code != Code.Ldtoken)
|
|
continue;
|
|
var typeToken = ldtoken.Operand as TypeReference;
|
|
if (typeToken == null)
|
|
continue;
|
|
var delegateType = getType(typeToken);
|
|
if (!DotNetUtils.isDelegateType(delegateType))
|
|
continue;
|
|
var invoke = DotNetUtils.getMethod(delegateType, "Invoke");
|
|
if (invoke == null || !DotNetUtils.isMethod(invoke, "System.String", "(System.Int32)"))
|
|
continue;
|
|
|
|
return delegateType;
|
|
}
|
|
|
|
return null;
|
|
}
|
|
|
|
// Finds the SmartAssembly.StringsEncoding.Strings class. This class decrypts the
|
|
// strings in the resources. It gets called by the SmartAssembly.Delegates.GetString
|
|
// delegate instances which were created by SmartAssembly.HouseOfCards.Strings.
|
|
TypeDefinition findStringDecrypterClass(MethodDefinition stringsCreateDelegateMethod) {
|
|
if (!stringsCreateDelegateMethod.HasBody)
|
|
return null;
|
|
|
|
foreach (var ldtoken in stringsCreateDelegateMethod.Body.Instructions) {
|
|
if (ldtoken.OpCode.Code != Code.Ldtoken)
|
|
continue;
|
|
var typeToken = ldtoken.Operand as TypeReference;
|
|
if (typeToken == null)
|
|
continue;
|
|
var type = getType(typeToken);
|
|
if (type == null || DotNetUtils.isDelegateType(type))
|
|
continue;
|
|
if (!couldBeStringDecrypterClass(type))
|
|
continue;
|
|
|
|
return type;
|
|
}
|
|
|
|
return null;
|
|
}
|
|
|
|
void findStringDecrypterClasses() {
|
|
var foundClasses = new Dictionary<TypeDefinition, bool>();
|
|
foreach (var info in stringsEncoderInfos)
|
|
foundClasses[info.StringDecrypterClass] = true;
|
|
|
|
foreach (var type in module.Types) {
|
|
if (!foundClasses.ContainsKey(type) && couldBeStringDecrypterClass(type)) {
|
|
stringsEncoderInfos.Add(new StringsEncoderInfo {
|
|
StringsType = null,
|
|
GetStringDelegate = null,
|
|
StringDecrypterClass = type,
|
|
});
|
|
}
|
|
}
|
|
}
|
|
|
|
bool couldBeStringDecrypterClass(TypeDefinition type) {
|
|
if (DotNetUtils.findFieldType(type, "System.Collections.Hashtable", true) == null &&
|
|
DotNetUtils.findFieldType(type, "System.Collections.Generic.Dictionary`2<System.Int32,System.String>", true) == null) {
|
|
return false;
|
|
}
|
|
if (DotNetUtils.getMethod(type, ".cctor") == null)
|
|
return false;
|
|
|
|
var methods = new List<MethodDefinition>(DotNetUtils.getNormalMethods(type));
|
|
if (methods.Count != 1)
|
|
return false;
|
|
var method = methods[0];
|
|
if (!DotNetUtils.isMethod(method, "System.String", "(System.Int32)"))
|
|
return false;
|
|
if (!method.IsStatic || !method.HasBody)
|
|
return false;
|
|
|
|
return true;
|
|
}
|
|
}
|
|
}
|