/*
Copyright (C) 2011-2013 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 System.Text;
using dnlib.IO;
using dnlib.DotNet;
using dnlib.DotNet.MD;
using dnlib.DotNet.Emit;
using de4dot.blocks;
namespace de4dot.code.deobfuscators.Confuser {
// Since v1.8 r75367
class ConstantsDecrypterV18 : IVersionProvider {
ModuleDefMD module;
byte[] fileData;
ISimpleDeobfuscator simpleDeobfuscator;
FieldDef dictField, dataField;
MethodDef installMethod;
MethodDefAndDeclaringTypeDict decrypters = new MethodDefAndDeclaringTypeDict();
uint key0, key0d;
MethodDef nativeMethod;
TypeDef lzmaType;
EmbeddedResource resource;
byte[] constants;
ConfuserVersion version = ConfuserVersion.Unknown;
public enum ConfuserVersion {
Unknown,
v18_r75367_normal,
v18_r75367_dynamic,
v18_r75367_native,
v18_r75369_normal,
v18_r75369_dynamic,
v18_r75369_native,
v19_r77172_normal,
v19_r77172_dynamic,
v19_r77172_native,
}
public class DecrypterInfo {
readonly ConstantsDecrypterV18 constantsDecrypter;
public readonly MethodDef method;
public ulong key0l, key1l, key2l;
public uint key0, key0d;
readonly ConfuserVersion version;
public DecrypterInfo(ConstantsDecrypterV18 constantsDecrypter, MethodDef method, ConfuserVersion version) {
this.constantsDecrypter = constantsDecrypter;
this.method = method;
this.version = version;
}
public string DecryptString(uint magic1, ulong magic2) {
return Encoding.UTF8.GetString(Decrypt(magic1, magic2));
}
public int DecryptInt32(uint magic1, ulong magic2) {
return BitConverter.ToInt32(Decrypt(magic1, magic2), 0);
}
public long DecryptInt64(uint magic1, ulong magic2) {
return BitConverter.ToInt64(Decrypt(magic1, magic2), 0);
}
public float DecryptSingle(uint magic1, ulong magic2) {
return BitConverter.ToSingle(Decrypt(magic1, magic2), 0);
}
public double DecryptDouble(uint magic1, ulong magic2) {
return BitConverter.ToDouble(Decrypt(magic1, magic2), 0);
}
byte[] Decrypt(uint magic1, ulong magic2) {
ulong info = Hash(method.DeclaringType.MDToken.ToUInt32() * magic1) ^ magic2;
int offset = (int)(info >> 32);
int len = (int)info;
var decrypted = new byte[len];
byte[] key = BitConverter.GetBytes(method.MDToken.ToUInt32() ^ key0d);
for (int i = 0; i < len; i++)
decrypted[i] = (byte)(constantsDecrypter.constants[offset + i] ^ key[(offset + i) & 3]);
return decrypted;
}
ulong Hash(uint magic) {
switch (version) {
case ConfuserVersion.v18_r75367_normal:
case ConfuserVersion.v18_r75367_dynamic:
case ConfuserVersion.v18_r75367_native:
return Hash1(key0l ^ magic);
case ConfuserVersion.v18_r75369_normal:
case ConfuserVersion.v18_r75369_dynamic:
case ConfuserVersion.v18_r75369_native:
case ConfuserVersion.v19_r77172_normal:
case ConfuserVersion.v19_r77172_dynamic:
case ConfuserVersion.v19_r77172_native:
return Hash1(key0l * magic);
default:
throw new ApplicationException("Invalid version");
}
}
ulong Hash1(ulong h0) {
ulong h1 = key1l;
ulong h2 = key2l;
h1 *= h0;
h2 *= h0;
h0 *= h0;
ulong hash = 14695981039346656037UL;
while (h0 != 0) {
hash *= 1099511628211UL;
hash = (hash ^ h0) + (h1 ^ h2) * key0;
h1 *= 0x811C9DC5;
h2 *= 0xA2CEBAB2;
h0 >>= 8;
}
return hash;
}
}
public IEnumerable Types {
get {
var types = new List();
foreach (var info in decrypters.GetValues())
types.Add(info.method.DeclaringType);
return types;
}
}
public IEnumerable Fields {
get {
return new List {
dataField,
dictField,
};
}
}
public MethodDef NativeMethod {
get { return nativeMethod; }
}
public TypeDef LzmaType {
get { return lzmaType; }
}
public EmbeddedResource Resource {
get { return resource; }
}
public IEnumerable Decrypters {
get { return decrypters.GetValues(); }
}
public bool Detected {
get { return installMethod != null; }
}
public ConstantsDecrypterV18(ModuleDefMD module, byte[] fileData, ISimpleDeobfuscator simpleDeobfuscator) {
this.module = module;
this.fileData = fileData;
this.simpleDeobfuscator = simpleDeobfuscator;
}
public void Find() {
var cctor = DotNetUtils.GetModuleTypeCctor(module);
if (cctor == null)
return;
simpleDeobfuscator.Deobfuscate(cctor, true);
if ((dictField = ConstantsDecrypterUtils.FindDictField(cctor, cctor.DeclaringType)) == null)
return;
if ((dataField = ConstantsDecrypterUtils.FindDataField_v18_r75367(cctor, cctor.DeclaringType)) == null &&
(dataField = ConstantsDecrypterUtils.FindDataField_v19_r77172(cctor, cctor.DeclaringType)) == null)
return;
nativeMethod = FindNativeMethod(cctor, cctor.DeclaringType);
var method = GetDecryptMethod();
if (method == null)
return;
simpleDeobfuscator.Deobfuscate(method);
var info = new DecrypterInfo(this, method, ConfuserVersion.Unknown);
if (FindKeys_v18_r75367(info))
InitVersion(cctor, ConfuserVersion.v18_r75367_normal, ConfuserVersion.v18_r75367_dynamic, ConfuserVersion.v18_r75367_native);
else if (FindKeys_v18_r75369(info)) {
lzmaType = ConfuserUtils.FindLzmaType(cctor);
if (lzmaType == null)
InitVersion(cctor, ConfuserVersion.v18_r75369_normal, ConfuserVersion.v18_r75369_dynamic, ConfuserVersion.v18_r75369_native);
else
InitVersion(cctor, ConfuserVersion.v19_r77172_normal, ConfuserVersion.v19_r77172_dynamic, ConfuserVersion.v19_r77172_native);
}
else
return;
installMethod = cctor;
}
void InitVersion(MethodDef installMethod, ConfuserVersion normal, ConfuserVersion dynamic, ConfuserVersion native) {
if (nativeMethod != null)
version = native;
else if (DeobUtils.HasInteger(installMethod, 0x10000))
version = normal;
else
version = dynamic;
}
public void Initialize() {
if (installMethod == null)
return;
if (!FindKeys())
throw new ApplicationException("Could not find keys");
if ((resource = FindResource(key0)) == null)
throw new ApplicationException("Could not find resource");
constants = DecryptResource(resource.GetResourceData());
FindDecrypters();
}
EmbeddedResource FindResource(uint magic) {
var name = Encoding.UTF8.GetString(BitConverter.GetBytes(magic));
return DotNetUtils.GetResource(module, name) as EmbeddedResource;
}
bool FindKeys() {
if (!FindKey0(installMethod, out key0))
return false;
if (!FindKey0d(installMethod, out key0d))
return false;
return true;
}
static bool FindKey0(MethodDef method, out uint key) {
var instrs = method.Body.Instructions;
for (int i = 0; i < instrs.Count; i++) {
int index = ConfuserUtils.FindCallMethod(instrs, i, Code.Call, "System.Text.Encoding System.Text.Encoding::get_UTF8()");
if (index < 0)
break;
int index2 = ConfuserUtils.FindCallMethod(instrs, i, Code.Call, "System.Byte[] System.BitConverter::GetBytes(System.Int32)");
if (index2 - index != 2)
continue;
var ldci4 = instrs[index + 1];
if (!ldci4.IsLdcI4())
continue;
key = (uint)ldci4.GetLdcI4Value();
return true;
}
key = 0;
return false;
}
static bool FindKey0d(MethodDef method, out uint key) {
var instrs = method.Body.Instructions;
for (int i = 0; i < instrs.Count; i++) {
int index = ConfuserUtils.FindCallMethod(instrs, i, Code.Callvirt, "System.Reflection.Module System.Reflection.MemberInfo::get_Module()");
if (index < 0)
break;
int index2 = ConfuserUtils.FindCallMethod(instrs, i, Code.Callvirt, "System.Int32 System.Reflection.MemberInfo::get_MetadataToken()");
if (index2 - index != 3)
continue;
var ldci4 = instrs[index + 1];
if (!ldci4.IsLdcI4())
continue;
if (!instrs[index + 2].IsLdloc())
continue;
key = (uint)ldci4.GetLdcI4Value();
return true;
}
key = 0;
return false;
}
static MethodDef FindNativeMethod(MethodDef method, TypeDef declaringType) {
var instrs = method.Body.Instructions;
for (int i = 0; i < instrs.Count; i++) {
if (!instrs[i].IsLdloc())
continue;
var call = instrs[i + 1];
if (call.OpCode.Code != Code.Call)
continue;
var calledMethod = call.Operand as MethodDef;
if (calledMethod == null || !calledMethod.IsStatic || !calledMethod.IsNative)
continue;
if (!DotNetUtils.IsMethod(calledMethod, "System.Int32", "(System.Int32)"))
continue;
return calledMethod;
}
return null;
}
MethodDef GetDecryptMethod() {
foreach (var type in module.Types) {
if (type.Attributes != (TypeAttributes.Abstract | TypeAttributes.Sealed))
continue;
if (!CheckMethods(type.Methods))
continue;
foreach (var method in type.Methods) {
if (IsDecryptMethodSignature(method))
return method;
}
}
return null;
}
static bool CheckMethods(IEnumerable methods) {
int numMethods = 0;
foreach (var method in methods) {
if (method.Name == ".ctor" || method.Name == ".cctor")
return false;
if (!IsDecryptMethodSignature(method))
return false;
numMethods++;
}
return numMethods > 0;
}
static bool IsDecryptMethodSignature(MethodDef method) {
if (method == null || method.Body == null)
return false;
if (method.Attributes != (MethodAttributes.Static | MethodAttributes.HideBySig | MethodAttributes.CompilerControlled))
return false;
var sig = method.MethodSig;
if (sig == null)
return false;
if (sig.Params.Count != 2)
return false;
if (sig.Params[0].GetElementType() != ElementType.U4)
return false;
if (sig.Params[1].GetElementType() != ElementType.U8)
return false;
if (!(sig.RetType.RemovePinnedAndModifiers() is GenericMVar))
return false;
if (sig.GenParamCount != 1)
return false;
return true;
}
void FindDecrypters() {
foreach (var type in module.Types) {
if (type.Attributes != (TypeAttributes.Abstract | TypeAttributes.Sealed))
continue;
if (!CheckMethods(type.Methods))
continue;
foreach (var method in type.Methods) {
var info = CreateDecrypterInfo(method);
if (info != null)
decrypters.Add(info.method, info);
}
}
}
DecrypterInfo CreateDecrypterInfo(MethodDef method) {
if (!IsDecryptMethodSignature(method))
return null;
simpleDeobfuscator.Deobfuscate(method);
var info = new DecrypterInfo(this, method, version);
if (!FindKeys(info))
return null;
return info;
}
bool FindKeys(DecrypterInfo info) {
switch (version) {
case ConfuserVersion.v18_r75367_normal:
case ConfuserVersion.v18_r75367_dynamic:
case ConfuserVersion.v18_r75367_native:
return FindKeys_v18_r75367(info);
case ConfuserVersion.v18_r75369_normal:
case ConfuserVersion.v18_r75369_dynamic:
case ConfuserVersion.v18_r75369_native:
case ConfuserVersion.v19_r77172_normal:
case ConfuserVersion.v19_r77172_dynamic:
case ConfuserVersion.v19_r77172_native:
return FindKeys_v18_r75369(info);
default:
throw new ApplicationException("Invalid version");
}
}
static bool FindKeys_v18_r75367(DecrypterInfo info) {
if (!FindLKeys_v18_r75367(info))
return false;
if (!FindKey0_v18_r75367(info))
return false;
if (!FindKey0d_v18_r75367(info))
return false;
return true;
}
static bool FindKeys_v18_r75369(DecrypterInfo info) {
if (!FindLKeys_v18_r75369(info))
return false;
if (!FindKey0_v18_r75369(info))
return false;
if (!FindKey0d_v18_r75367(info))
return false;
return true;
}
static bool FindLKeys_v18_r75367(DecrypterInfo info) {
var instrs = info.method.Body.Instructions;
for (int i = 0; i < instrs.Count - 10; i++) {
var ldci4_1 = instrs[i];
if (!ldci4_1.IsLdcI4())
continue;
if (!instrs[i + 1].IsLdloc())
continue;
if (instrs[i + 2].OpCode.Code != Code.Xor)
continue;
if (instrs[i + 3].OpCode.Code != Code.Conv_U8)
continue;
if (!instrs[i + 4].IsStloc())
continue;
var ldci4_2 = instrs[i + 5];
if (!ldci4_2.IsLdcI4())
continue;
if (instrs[i + 6].OpCode.Code != Code.Conv_I8)
continue;
if (!instrs[i + 7].IsStloc())
continue;
var ldci4_3 = instrs[i + 8];
if (!ldci4_3.IsLdcI4())
continue;
if (instrs[i + 9].OpCode.Code != Code.Conv_I8)
continue;
if (!instrs[i + 10].IsStloc())
continue;
info.key0l = (uint)ldci4_1.GetLdcI4Value();
info.key1l = (uint)ldci4_2.GetLdcI4Value();
info.key2l = (uint)ldci4_3.GetLdcI4Value();
return true;
}
return false;
}
static bool FindKey0_v18_r75367(DecrypterInfo info) {
var instrs = info.method.Body.Instructions;
for (int i = 0; i < instrs.Count - 4; i++) {
if (instrs[i].OpCode.Code != Code.Xor)
continue;
var ldci4 = instrs[i + 1];
if (!ldci4.IsLdcI4())
continue;
if (instrs[i + 2].OpCode.Code != Code.Conv_I8)
continue;
if (instrs[i + 3].OpCode.Code != Code.Mul)
continue;
if (instrs[i + 4].OpCode.Code != Code.Add)
continue;
info.key0 = (uint)ldci4.GetLdcI4Value();
return true;
}
return false;
}
static bool FindKey0d_v18_r75367(DecrypterInfo info) {
var instrs = info.method.Body.Instructions;
for (int i = 0; i < instrs.Count; i++) {
int index = ConfuserUtils.FindCallMethod(instrs, i, Code.Callvirt, "System.Int32 System.Reflection.MemberInfo::get_MetadataToken()");
if (index < 0)
break;
int index2 = ConfuserUtils.FindCallMethod(instrs, index, Code.Call, "System.Byte[] System.BitConverter::GetBytes(System.Int32)");
if (index2 < 0)
break;
if (index2 - index != 3)
continue;
var ldci4 = instrs[index + 1];
if (!ldci4.IsLdcI4())
continue;
if (instrs[index + 2].OpCode.Code != Code.Xor)
continue;
info.key0d = (uint)ldci4.GetLdcI4Value();
return true;
}
return false;
}
static bool FindLKeys_v18_r75369(DecrypterInfo info) {
var instrs = info.method.Body.Instructions;
for (int i = 0; i < instrs.Count - 8; i++) {
var ldci8_1 = instrs[i];
if (ldci8_1.OpCode.Code != Code.Ldc_I8)
continue;
if (!instrs[i + 1].IsLdloc())
continue;
if (instrs[i + 2].OpCode.Code != Code.Conv_U8)
continue;
if (instrs[i + 3].OpCode.Code != Code.Mul)
continue;
if (!instrs[i + 4].IsStloc())
continue;
var ldci8_2 = instrs[i + 5];
if (ldci8_2.OpCode.Code != Code.Ldc_I8)
continue;
if (!instrs[i + 6].IsStloc())
continue;
var ldci8_3 = instrs[i + 7];
if (ldci8_3.OpCode.Code != Code.Ldc_I8)
continue;
if (!instrs[i + 8].IsStloc())
continue;
info.key0l = (ulong)(long)ldci8_1.Operand;
info.key1l = (ulong)(long)ldci8_2.Operand;
info.key2l = (ulong)(long)ldci8_3.Operand;
return true;
}
return false;
}
static bool FindKey0_v18_r75369(DecrypterInfo info) {
var instrs = info.method.Body.Instructions;
for (int i = 0; i < instrs.Count - 4; i++) {
if (!instrs[i].IsLdloc())
continue;
if (instrs[i + 1].OpCode.Code != Code.Xor)
continue;
var ldci4 = instrs[i + 2];
if (!ldci4.IsLdcI4())
continue;
if (instrs[i + 3].OpCode.Code != Code.Conv_U8)
continue;
if (instrs[i + 4].OpCode.Code != Code.Mul)
continue;
info.key0 = (uint)ldci4.GetLdcI4Value();
return true;
}
return false;
}
byte[] Decompress(byte[] compressed) {
if (lzmaType != null)
return ConfuserUtils.SevenZipDecompress(compressed);
return DeobUtils.Inflate(compressed, true);
}
byte[] DecryptResource(byte[] encrypted) {
switch (version) {
case ConfuserVersion.v18_r75367_normal:
case ConfuserVersion.v18_r75369_normal:
case ConfuserVersion.v19_r77172_normal:
return DecryptResource_v18_r75367_normal(encrypted);
case ConfuserVersion.v18_r75367_dynamic:
case ConfuserVersion.v18_r75369_dynamic:
case ConfuserVersion.v19_r77172_dynamic:
return DecryptResource_v18_r75367_dynamic(encrypted);
case ConfuserVersion.v18_r75367_native:
case ConfuserVersion.v18_r75369_native:
case ConfuserVersion.v19_r77172_native:
return DecryptResource_v18_r75367_native(encrypted);
default:
throw new ApplicationException("Unknown version");
}
}
byte[] GetSigKey() {
return module.ReadBlob(key0d ^ installMethod.MDToken.ToUInt32());
}
byte[] DecryptResource_v18_r75367_normal(byte[] encrypted) {
var key = GetSigKey();
var decrypted = ConfuserUtils.Decrypt(BitConverter.ToUInt32(key, 12) * (uint)key0, encrypted);
return Decompress(DeobUtils.AesDecrypt(decrypted, key, DeobUtils.Md5Sum(key)));
}
static int GetDynamicStartIndex(IList instrs, int ldlocIndex) {
for (int i = ldlocIndex - 1; i >= 0; i--) {
if (instrs[i].OpCode.FlowControl != FlowControl.Next)
return i + 1;
}
return 0;
}
int GetDynamicEndIndex(int startIndex, Local local) {
if (startIndex < 0)
return -1;
var instrs = installMethod.Body.Instructions;
for (int i = startIndex; i < instrs.Count; i++) {
var instr = instrs[i];
if (instr.IsStloc() && instr.GetLocal(installMethod.Body.Variables) == local)
return i;
}
return -1;
}
Local GetDynamicLocal(out int instrIndex) {
var instrs = installMethod.Body.Instructions;
for (int i = 0; i < instrs.Count; i++) {
i = ConfuserUtils.FindCallMethod(instrs, i, Code.Callvirt, "System.Void System.IO.BinaryWriter::Write(System.Byte)");
if (i < 0)
break;
int index = i - 2;
if (index < 0)
continue;
var ldloc = instrs[index];
if (!ldloc.IsLdloc())
continue;
if (instrs[index + 1].OpCode.Code != Code.Conv_U1)
continue;
instrIndex = index;
return ldloc.GetLocal(installMethod.Body.Variables);
}
instrIndex = 0;
return null;
}
byte[] DecryptResource_v18_r75367_dynamic(byte[] encrypted) {
int ldlocIndex;
var local = GetDynamicLocal(out ldlocIndex);
if (local == null)
throw new ApplicationException("Could not find local");
var instrs = installMethod.Body.Instructions;
int startIndex = GetDynamicStartIndex(instrs, ldlocIndex);
int endIndex = GetDynamicEndIndex(startIndex, local);
if (endIndex < 0)
throw new ApplicationException("Could not find endIndex");
var constReader = new ConstantsReader(installMethod);
return DecryptResource(encrypted, magic => {
constReader.SetConstantInt32(local, magic);
int index = startIndex, result;
if (!constReader.GetNextInt32(ref index, out result))
throw new ApplicationException("Could not get constant");
if (index != endIndex)
throw new ApplicationException("Wrong constant");
return (byte)result;
});
}
byte[] DecryptResource_v18_r75367_native(byte[] encrypted) {
using (var x86Emu = new x86Emulator(fileData))
return DecryptResource(encrypted, magic => (byte)x86Emu.Emulate((uint)nativeMethod.RVA, magic));
}
byte[] DecryptResource(byte[] encrypted, Func decryptFunc) {
var key = GetSigKey();
byte[] decrypted = DecryptAndDecompress(encrypted, key);
var reader = MemoryImageStream.Create(decrypted);
var result = new MemoryStream();
var writer = new BinaryWriter(result);
while (reader.Position < reader.Length) {
uint magic = reader.Read7BitEncodedUInt32();
writer.Write(decryptFunc(magic));
}
return result.ToArray();
}
byte[] DecryptAndDecompress(byte[] encrypted, byte[] key) {
byte[] iv = DeobUtils.Md5Sum(key);
try {
return Decompress(DeobUtils.AesDecrypt(encrypted, key, iv));
}
catch {
return DeobUtils.AesDecrypt(Decompress(encrypted), key, iv);
}
}
static bool VerifyGenericArg(MethodSpec gim, ElementType etype) {
if (gim == null)
return false;
var gims = gim.GenericInstMethodSig;
if (gims == null || gims.GenericArguments.Count != 1)
return false;
return gims.GenericArguments[0].GetElementType() == etype;
}
public string DecryptString(MethodDef method, MethodSpec gim, uint magic1, ulong magic2) {
if (!VerifyGenericArg(gim, ElementType.String))
return null;
var info = decrypters.Find(method);
return info.DecryptString(magic1, magic2);
}
public object DecryptInt32(MethodDef method, MethodSpec gim, uint magic1, ulong magic2) {
if (!VerifyGenericArg(gim, ElementType.I4))
return null;
var info = decrypters.Find(method);
return info.DecryptInt32(magic1, magic2);
}
public object DecryptInt64(MethodDef method, MethodSpec gim, uint magic1, ulong magic2) {
if (!VerifyGenericArg(gim, ElementType.I8))
return null;
var info = decrypters.Find(method);
return info.DecryptInt64(magic1, magic2);
}
public object DecryptSingle(MethodDef method, MethodSpec gim, uint magic1, ulong magic2) {
if (!VerifyGenericArg(gim, ElementType.R4))
return null;
var info = decrypters.Find(method);
return info.DecryptSingle(magic1, magic2);
}
public object DecryptDouble(MethodDef method, MethodSpec gim, uint magic1, ulong magic2) {
if (!VerifyGenericArg(gim, ElementType.R8))
return null;
var info = decrypters.Find(method);
return info.DecryptDouble(magic1, magic2);
}
public void CleanUp() {
if (installMethod == null)
return;
//TODO: Only remove its code
installMethod.Body.Instructions.Clear();
installMethod.Body.Instructions.Add(Instruction.Create(OpCodes.Ret));
}
public bool GetRevisionRange(out int minRev, out int maxRev) {
switch (version) {
case ConfuserVersion.Unknown:
minRev = maxRev = 0;
return false;
case ConfuserVersion.v18_r75367_normal:
case ConfuserVersion.v18_r75367_dynamic:
case ConfuserVersion.v18_r75367_native:
minRev = 75367;
maxRev = 75367;
return true;
case ConfuserVersion.v18_r75369_normal:
case ConfuserVersion.v18_r75369_dynamic:
case ConfuserVersion.v18_r75369_native:
minRev = 75369;
maxRev = 77124;
return true;
case ConfuserVersion.v19_r77172_normal:
case ConfuserVersion.v19_r77172_dynamic:
case ConfuserVersion.v19_r77172_native:
minRev = 77172;
maxRev = int.MaxValue;
return true;
default: throw new ApplicationException("Invalid version");
}
}
}
}