141 lines
3.9 KiB
C#
141 lines
3.9 KiB
C#
/*
|
|
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 <http://www.gnu.org/licenses/>.
|
|
*/
|
|
|
|
using System.Collections.Generic;
|
|
using System.IO;
|
|
using Mono.Cecil;
|
|
using de4dot.blocks;
|
|
|
|
namespace de4dot.code.deobfuscators.Babel_NET {
|
|
class StringDecrypter {
|
|
ModuleDefinition module;
|
|
Dictionary<int, string> offsetToString = new Dictionary<int, string>();
|
|
TypeDefinition decrypterType;
|
|
MethodDefinition decryptMethod;
|
|
EmbeddedResource encryptedResource;
|
|
|
|
public bool Detected {
|
|
get { return decrypterType != null; }
|
|
}
|
|
|
|
public TypeDefinition Type {
|
|
get { return decrypterType; }
|
|
}
|
|
|
|
public MethodDefinition DecryptMethod {
|
|
get { return decryptMethod; }
|
|
}
|
|
|
|
public EmbeddedResource Resource {
|
|
get { return encryptedResource; }
|
|
}
|
|
|
|
public StringDecrypter(ModuleDefinition module) {
|
|
this.module = module;
|
|
}
|
|
|
|
public void find() {
|
|
foreach (var type in module.Types) {
|
|
if (!isDecrypterType(type))
|
|
continue;
|
|
|
|
var method = DotNetUtils.getMethod(type, "System.String", "(System.Int32)");
|
|
if (method == null)
|
|
continue;
|
|
|
|
decrypterType = type;
|
|
decryptMethod = method;
|
|
return;
|
|
}
|
|
}
|
|
|
|
bool isDecrypterType(TypeDefinition type) {
|
|
if (type.HasEvents)
|
|
return false;
|
|
if (type.NestedTypes.Count != 1)
|
|
return false;
|
|
if (type.Fields.Count != 0)
|
|
return false;
|
|
|
|
var nested = type.NestedTypes[0];
|
|
if (nested.HasProperties || nested.HasEvents)
|
|
return false;
|
|
|
|
if (nested.Fields.Count == 1) {
|
|
// 4.2+ (maybe 4.0+)
|
|
|
|
if (!MemberReferenceHelper.compareTypes(nested.Fields[0].FieldType, nested))
|
|
return false;
|
|
|
|
if (DotNetUtils.getMethod(nested, "System.Reflection.Emit.MethodBuilder", "(System.Reflection.Emit.TypeBuilder)") == null)
|
|
return false;
|
|
}
|
|
else if (nested.Fields.Count == 2) {
|
|
// 3.5 and maybe earlier
|
|
|
|
var field1 = nested.Fields[0];
|
|
var field2 = nested.Fields[1];
|
|
if (field1.FieldType.FullName != "System.Collections.Hashtable" && field2.FieldType.FullName != "System.Collections.Hashtable")
|
|
return false;
|
|
if (!MemberReferenceHelper.compareTypes(field1.FieldType, nested) && !MemberReferenceHelper.compareTypes(field2.FieldType, nested))
|
|
return false;
|
|
}
|
|
else
|
|
return false;
|
|
|
|
if (DotNetUtils.getMethod(nested, ".ctor") == null)
|
|
return false;
|
|
if (DotNetUtils.getMethod(nested, "System.String", "(System.Int32)") == null)
|
|
return false;
|
|
|
|
return true;
|
|
}
|
|
|
|
public void initialize() {
|
|
if (decrypterType == null)
|
|
return;
|
|
if (encryptedResource != null)
|
|
return;
|
|
encryptedResource = findResource();
|
|
if (encryptedResource == null)
|
|
return;
|
|
|
|
var decrypted = new ResourceDecrypter(module).decrypt(encryptedResource.GetResourceData());
|
|
var reader = new BinaryReader(new MemoryStream(decrypted));
|
|
while (reader.BaseStream.Position < reader.BaseStream.Length)
|
|
offsetToString[(int)reader.BaseStream.Position] = reader.ReadString();
|
|
}
|
|
|
|
EmbeddedResource findResource() {
|
|
foreach (var method in decrypterType.Methods) {
|
|
foreach (var s in DotNetUtils.getCodeStrings(method)) {
|
|
var resource = DotNetUtils.getResource(module, s) as EmbeddedResource;
|
|
if (resource != null)
|
|
return resource;
|
|
}
|
|
}
|
|
return null;
|
|
}
|
|
|
|
public string decrypt(int offset) {
|
|
return offsetToString[offset];
|
|
}
|
|
}
|
|
}
|