de4dot-cex/de4dot.code/deobfuscators/Babel_NET/ResourceResolver.cs
2012-01-07 20:27:07 +01:00

141 lines
4.0 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.IO;
using Mono.Cecil;
using Mono.Cecil.Cil;
using de4dot.blocks;
namespace de4dot.code.deobfuscators.Babel_NET {
class ResourceResolver {
ModuleDefinition module;
TypeDefinition resolverType;
MethodDefinition registerMethod;
EmbeddedResource encryptedResource;
public bool Detected {
get { return resolverType != null; }
}
public TypeDefinition Type {
get { return resolverType; }
}
public MethodDefinition InitMethod {
get { return registerMethod; }
}
public ResourceResolver(ModuleDefinition module) {
this.module = module;
}
public void find() {
var requiredTypes = new string[] {
"System.Reflection.Assembly",
"System.Object",
"System.Int32",
"System.String[]",
};
foreach (var type in module.Types) {
if (type.HasEvents)
continue;
if (!new FieldTypes(type).exactly(requiredTypes))
continue;
MethodDefinition regMethod, handler;
if (!findRegisterMethod(type, out regMethod, out handler))
continue;
var resource = findEmbeddedResource(type);
if (resource == null)
continue;
resolverType = type;
registerMethod = regMethod;
encryptedResource = resource;
return;
}
}
bool findRegisterMethod(TypeDefinition type, out MethodDefinition regMethod, out MethodDefinition handler) {
foreach (var method in type.Methods) {
if (!method.IsStatic || method.Body == null)
continue;
if (method.Body.ExceptionHandlers.Count != 1)
continue;
foreach (var instr in method.Body.Instructions) {
if (instr.OpCode.Code != Code.Ldftn)
continue;
var handlerRef = instr.Operand as MethodReference;
if (handlerRef == null)
continue;
if (!DotNetUtils.isMethod(handlerRef, "System.Reflection.Assembly", "(System.Object,System.ResolveEventArgs)"))
continue;
if (!MemberReferenceHelper.compareTypes(type, handlerRef.DeclaringType))
continue;
handler = DotNetUtils.getMethod(type, handlerRef);
if (handler == null)
continue;
if (handler.Body == null || handler.Body.ExceptionHandlers.Count != 1)
continue;
regMethod = method;
return true;
}
}
regMethod = null;
handler = null;
return false;
}
EmbeddedResource findEmbeddedResource(TypeDefinition type) {
foreach (var method in type.Methods) {
if (!DotNetUtils.isMethod(method, "System.String", "()"))
continue;
foreach (var s in DotNetUtils.getCodeStrings(method)) {
var resource = DotNetUtils.getResource(module, s) as EmbeddedResource;
if (resource != null)
return resource;
}
}
return null;
}
public EmbeddedResource mergeResources() {
if (encryptedResource == null)
return null;
DeobUtils.decryptAndAddResources(module, encryptedResource.Name, () => decryptResourceAssembly());
var result = encryptedResource;
encryptedResource = null;
return result;
}
byte[] decryptResourceAssembly() {
var decrypted = new ResourceDecrypter(module).decrypt(encryptedResource.GetResourceData());
var reader = new BinaryReader(new MemoryStream(decrypted));
int numResources = reader.ReadInt32();
for (int i = 0; i < numResources; i++)
reader.ReadString();
return reader.ReadBytes((int)(reader.BaseStream.Length - reader.BaseStream.Position));
}
}
}