288 lines
8.4 KiB
C#
288 lines
8.4 KiB
C#
/*
|
|
Copyright (C) 2011-2015 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;
|
|
using System.Collections.Generic;
|
|
using System.IO;
|
|
using System.Runtime.Serialization.Formatters.Binary;
|
|
using dnlib.IO;
|
|
using dnlib.DotNet;
|
|
using dnlib.DotNet.Emit;
|
|
using de4dot.blocks;
|
|
|
|
namespace de4dot.code.deobfuscators.Babel_NET {
|
|
class ConstantsDecrypter {
|
|
ModuleDefMD module;
|
|
ResourceDecrypter resourceDecrypter;
|
|
InitializedDataCreator initializedDataCreator;
|
|
TypeDef decrypterType;
|
|
MethodDef int32Decrypter;
|
|
MethodDef int64Decrypter;
|
|
MethodDef singleDecrypter;
|
|
MethodDef doubleDecrypter;
|
|
MethodDef arrayDecrypter;
|
|
EmbeddedResource encryptedResource;
|
|
int[] decryptedInts;
|
|
long[] decryptedLongs;
|
|
float[] decryptedFloats;
|
|
double[] decryptedDoubles;
|
|
|
|
public bool Detected {
|
|
get { return decrypterType != null; }
|
|
}
|
|
|
|
public bool CanDecrypt {
|
|
get { return encryptedResource != null; }
|
|
}
|
|
|
|
public Resource Resource {
|
|
get { return encryptedResource; }
|
|
}
|
|
|
|
public TypeDef Type {
|
|
get { return decrypterType; }
|
|
}
|
|
|
|
public MethodDef Int32Decrypter {
|
|
get { return int32Decrypter; }
|
|
}
|
|
|
|
public MethodDef Int64Decrypter {
|
|
get { return int64Decrypter; }
|
|
}
|
|
|
|
public MethodDef SingleDecrypter {
|
|
get { return singleDecrypter; }
|
|
}
|
|
|
|
public MethodDef DoubleDecrypter {
|
|
get { return doubleDecrypter; }
|
|
}
|
|
|
|
public MethodDef ArrayDecrypter {
|
|
get { return arrayDecrypter; }
|
|
}
|
|
|
|
public ConstantsDecrypter(ModuleDefMD module, ResourceDecrypter resourceDecrypter, InitializedDataCreator initializedDataCreator) {
|
|
this.module = module;
|
|
this.resourceDecrypter = resourceDecrypter;
|
|
this.initializedDataCreator = initializedDataCreator;
|
|
}
|
|
|
|
public void Find() {
|
|
foreach (var type in module.Types) {
|
|
if (!IsConstantDecrypter(type))
|
|
continue;
|
|
|
|
int32Decrypter = DotNetUtils.GetMethod(type, "System.Int32", "(System.Int32)");
|
|
int64Decrypter = DotNetUtils.GetMethod(type, "System.Int64", "(System.Int32)");
|
|
singleDecrypter = DotNetUtils.GetMethod(type, "System.Single", "(System.Int32)");
|
|
doubleDecrypter = DotNetUtils.GetMethod(type, "System.Double", "(System.Int32)");
|
|
arrayDecrypter = DotNetUtils.GetMethod(type, "System.Array", "(System.Byte[])");
|
|
decrypterType = type;
|
|
return;
|
|
}
|
|
}
|
|
|
|
bool IsConstantDecrypter(TypeDef type) {
|
|
if (type.HasEvents)
|
|
return false;
|
|
if (type.NestedTypes.Count != 1)
|
|
return false;
|
|
|
|
var nested = type.NestedTypes[0];
|
|
if (!CheckNestedFields(nested))
|
|
return false;
|
|
|
|
resourceDecrypter.DecryptMethod = ResourceDecrypter.FindDecrypterMethod(nested.FindMethod(".ctor"));
|
|
|
|
if (DotNetUtils.GetMethod(type, "System.Int32", "(System.Int32)") == null)
|
|
return false;
|
|
if (DotNetUtils.GetMethod(type, "System.Int64", "(System.Int32)") == null)
|
|
return false;
|
|
if (DotNetUtils.GetMethod(type, "System.Single", "(System.Int32)") == null)
|
|
return false;
|
|
if (DotNetUtils.GetMethod(type, "System.Double", "(System.Int32)") == null)
|
|
return false;
|
|
if (DotNetUtils.GetMethod(type, "System.Array", "(System.Byte[])") == null)
|
|
return false;
|
|
|
|
return true;
|
|
}
|
|
|
|
static string[] requiredTypes = new string[] {
|
|
"System.Int32[]",
|
|
"System.Int64[]",
|
|
"System.Single[]",
|
|
"System.Double[]",
|
|
};
|
|
bool CheckNestedFields(TypeDef nested) {
|
|
if (!new FieldTypes(nested).All(requiredTypes))
|
|
return false;
|
|
foreach (var field in nested.Fields) {
|
|
if (new SigComparer().Equals(nested, field.FieldSig.GetFieldType()))
|
|
return true;
|
|
}
|
|
return false;
|
|
}
|
|
|
|
public void Initialize(ISimpleDeobfuscator simpleDeobfuscator, IDeobfuscator deob) {
|
|
if (decrypterType == null)
|
|
return;
|
|
|
|
encryptedResource = BabelUtils.FindEmbeddedResource(module, decrypterType, simpleDeobfuscator, deob);
|
|
if (encryptedResource == null) {
|
|
Logger.w("Could not find encrypted constants resource");
|
|
return;
|
|
}
|
|
|
|
var decrypted = resourceDecrypter.Decrypt(encryptedResource.Data.ReadAllBytes());
|
|
var reader = new BinaryReader(new MemoryStream(decrypted));
|
|
int count;
|
|
|
|
count = reader.ReadInt32();
|
|
decryptedInts = new int[count];
|
|
while (count-- > 0)
|
|
decryptedInts[count] = reader.ReadInt32();
|
|
|
|
count = reader.ReadInt32();
|
|
decryptedLongs = new long[count];
|
|
while (count-- > 0)
|
|
decryptedLongs[count] = reader.ReadInt64();
|
|
|
|
count = reader.ReadInt32();
|
|
decryptedFloats = new float[count];
|
|
while (count-- > 0)
|
|
decryptedFloats[count] = reader.ReadSingle();
|
|
|
|
count = reader.ReadInt32();
|
|
decryptedDoubles = new double[count];
|
|
while (count-- > 0)
|
|
decryptedDoubles[count] = reader.ReadDouble();
|
|
}
|
|
|
|
public int DecryptInt32(int index) {
|
|
return decryptedInts[index];
|
|
}
|
|
|
|
public long DecryptInt64(int index) {
|
|
return decryptedLongs[index];
|
|
}
|
|
|
|
public float DecryptSingle(int index) {
|
|
return decryptedFloats[index];
|
|
}
|
|
|
|
public double DecryptDouble(int index) {
|
|
return decryptedDoubles[index];
|
|
}
|
|
|
|
struct ArrayInfo {
|
|
public FieldDef encryptedField;
|
|
public SZArraySig arrayType;
|
|
public int start, len;
|
|
|
|
public ArrayInfo(int start, int len, FieldDef encryptedField, SZArraySig arrayType) {
|
|
this.start = start;
|
|
this.len = len;
|
|
this.encryptedField = encryptedField;
|
|
this.arrayType = arrayType;
|
|
}
|
|
}
|
|
|
|
public void Deobfuscate(Blocks blocks) {
|
|
if (arrayDecrypter == null)
|
|
return;
|
|
|
|
var infos = new List<ArrayInfo>();
|
|
foreach (var block in blocks.MethodBlocks.GetAllBlocks()) {
|
|
var instrs = block.Instructions;
|
|
infos.Clear();
|
|
for (int i = 0; i < instrs.Count - 6; i++) {
|
|
int index = i;
|
|
|
|
var ldci4 = instrs[index++];
|
|
if (!ldci4.IsLdcI4())
|
|
continue;
|
|
|
|
var newarr = instrs[index++];
|
|
if (newarr.OpCode.Code != Code.Newarr)
|
|
continue;
|
|
if (newarr.Operand == null || newarr.Operand.ToString() != "System.Byte")
|
|
continue;
|
|
|
|
if (instrs[index++].OpCode.Code != Code.Dup)
|
|
continue;
|
|
|
|
var ldtoken = instrs[index++];
|
|
if (ldtoken.OpCode.Code != Code.Ldtoken)
|
|
continue;
|
|
var field = ldtoken.Operand as FieldDef;
|
|
if (field == null)
|
|
continue;
|
|
|
|
var call1 = instrs[index++];
|
|
if (call1.OpCode.Code != Code.Call && call1.OpCode.Code != Code.Callvirt)
|
|
continue;
|
|
if (!DotNetUtils.IsMethod(call1.Operand as IMethod, "System.Void", "(System.Array,System.RuntimeFieldHandle)"))
|
|
continue;
|
|
|
|
var call2 = instrs[index++];
|
|
if (call2.OpCode.Code != Code.Call && call2.OpCode.Code != Code.Callvirt)
|
|
continue;
|
|
if (!MethodEqualityComparer.CompareDeclaringTypes.Equals(call2.Operand as IMethod, arrayDecrypter))
|
|
continue;
|
|
|
|
var castclass = instrs[index++];
|
|
if (castclass.OpCode.Code != Code.Castclass)
|
|
continue;
|
|
var arrayType = (castclass.Operand as ITypeDefOrRef).TryGetSZArraySig();
|
|
if (arrayType == null)
|
|
continue;
|
|
if (arrayType.Next.ElementType.GetPrimitiveSize() == -1) {
|
|
Logger.w("Can't decrypt non-primitive type array in method {0:X8}", blocks.Method.MDToken.ToInt32());
|
|
continue;
|
|
}
|
|
|
|
infos.Add(new ArrayInfo(i, index - i, field, arrayType));
|
|
}
|
|
|
|
infos.Reverse();
|
|
foreach (var info in infos) {
|
|
var elemSize = info.arrayType.Next.ElementType.GetPrimitiveSize();
|
|
var decrypted = DecryptArray(info.encryptedField.InitialValue, elemSize);
|
|
|
|
initializedDataCreator.AddInitializeArrayCode(block, info.start, info.len, info.arrayType.Next.ToTypeDefOrRef(), decrypted);
|
|
Logger.v("Decrypted {0} array: {1} elements", info.arrayType.Next.ToString(), decrypted.Length / elemSize);
|
|
}
|
|
}
|
|
}
|
|
|
|
byte[] DecryptArray(byte[] encryptedData, int elemSize) {
|
|
var decrypted = resourceDecrypter.Decrypt(encryptedData);
|
|
var ary = (Array)new BinaryFormatter().Deserialize(new MemoryStream(decrypted));
|
|
if (ary is byte[])
|
|
return (byte[])ary;
|
|
var newAry = new byte[ary.Length * elemSize];
|
|
Buffer.BlockCopy(ary, 0, newAry, 0, newAry.Length);
|
|
return newAry;
|
|
}
|
|
}
|
|
}
|