public bool decrypt(PeImage peImage, ISimpleDeobfuscator simpleDeobfuscator, ref Dictionary<uint, DumpedMethod> dumpedMethods, Dictionary<uint,byte[]> tokenToNativeCode)
{
if (encryptedResource.Method == null)
return false;
encryptedResource.init(simpleDeobfuscator);
if (!encryptedResource.FoundResource)
return false;
var methodsData = encryptedResource.decrypt();
bool hooksJitter = findDnrCompileMethod(encryptedResource.Method.DeclaringType) != null;
xorKey = getXorKey();
xorEncrypt(methodsData);
var methodsDataReader = new BinaryReader(new MemoryStream(methodsData));
int patchCount = methodsDataReader.ReadInt32();
int mode = methodsDataReader.ReadInt32();
int tmp = methodsDataReader.ReadInt32();
methodsDataReader.BaseStream.Position -= 4;
if ((tmp & 0xFF000000) == 0x06000000) {
// It's method token + rva. DNR 3.7.0.3 (and earlier?) - 3.9.0.1
methodsDataReader.BaseStream.Position += 8L * patchCount;
patchCount = methodsDataReader.ReadInt32();
mode = methodsDataReader.ReadInt32();
patchDwords(peImage, methodsDataReader, patchCount);
while (methodsDataReader.BaseStream.Position < methodsData.Length - 1) {
uint token = methodsDataReader.ReadUInt32();
int numDwords = methodsDataReader.ReadInt32();
patchDwords(peImage, methodsDataReader, numDwords / 2);
}
}
else if (!hooksJitter || mode == 1) {
// DNR 3.9.8.0, 4.0, 4.1, 4.2, 4.3, 4.4
patchDwords(peImage, methodsDataReader, patchCount);
while (methodsDataReader.BaseStream.Position < methodsData.Length - 1) {
uint rva = methodsDataReader.ReadUInt32();
uint token = methodsDataReader.ReadUInt32(); // token, unknown, or index
int size = methodsDataReader.ReadInt32();
if (size > 0)
peImage.dotNetSafeWrite(rva, methodsDataReader.ReadBytes(size));
}
}
else {
// DNR 4.0 - 4.4 (jitter is hooked)
var metadataTables = peImage.Cor20Header.createMetadataTables();
var methodDef = metadataTables.getMetadataType(PE.MetadataIndex.iMethodDef);
var rvaToIndex = new Dictionary<uint, int>((int)methodDef.rows);
uint offset = methodDef.fileOffset;
for (int i = 0; i < methodDef.rows; i++) {
uint rva = peImage.offsetReadUInt32(offset);
offset += methodDef.totalSize;
if (rva == 0)
continue;
if ((peImage.readByte(rva) & 3) == 2)
rva++;
else
rva += (uint)(4 * (peImage.readByte(rva + 1) >> 4));
rvaToIndex[rva] = i;
}
patchDwords(peImage, methodsDataReader, patchCount);
int count = methodsDataReader.ReadInt32();
dumpedMethods = new Dictionary<uint, DumpedMethod>();
while (methodsDataReader.BaseStream.Position < methodsData.Length - 1) {
uint rva = methodsDataReader.ReadUInt32();
uint index = methodsDataReader.ReadUInt32();
bool isNativeCode = index >= 0x70000000;
int size = methodsDataReader.ReadInt32();
var methodData = methodsDataReader.ReadBytes(size);
int methodIndex;
if (!rvaToIndex.TryGetValue(rva, out methodIndex)) {
Log.w("Could not find method having code RVA {0:X8}", rva);
continue;
}
uint methodToken = 0x06000001 + (uint)methodIndex;
if (isNativeCode) {
totalEncryptedNativeMethods++;
if (tokenToNativeCode != null)
tokenToNativeCode[methodToken] = methodData;
// Convert return true / false methods. The others are converted to
// throw 0xDEADCODE.
if (DeobUtils.isCode(nativeLdci4, methodData)) {
uint val = BitConverter.ToUInt32(methodData, 4);
// ldc.i4 XXXXXXXXh / ret
methodData = new byte[] { 0x20, 0, 0, 0, 0, 0x2A };
methodData[1] = (byte)val;
methodData[2] = (byte)(val >> 8);
methodData[3] = (byte)(val >> 16);
methodData[4] = (byte)(val >> 24);
}
else if (DeobUtils.isCode(nativeLdci4_0, methodData)) {
// ldc.i4.0 / ret
methodData = new byte[] { 0x16, 0x2A };
}
else {
tokenToNativeMethod[methodToken] = methodData;
// ldc.i4 0xDEADCODE / conv.u4 / throw
methodData = new byte[] { 0x20, 0xDE, 0xC0, 0xAD, 0xDE, 0x6D, 0x7A };
}
}
var dm = new DumpedMethod();
dm.token = methodToken;
dm.code = methodData;
offset = methodDef.fileOffset + (uint)(methodIndex * methodDef.totalSize);
rva = peImage.offsetReadUInt32(offset);
dm.mdImplFlags = peImage.offsetReadUInt16(offset + (uint)methodDef.fields[1].offset);
dm.mdFlags = peImage.offsetReadUInt16(offset + (uint)methodDef.fields[2].offset);
dm.mdName = peImage.offsetRead(offset + (uint)methodDef.fields[3].offset, methodDef.fields[3].size);
dm.mdSignature = peImage.offsetRead(offset + (uint)methodDef.fields[4].offset, methodDef.fields[4].size);
dm.mdParamList = peImage.offsetRead(offset + (uint)methodDef.fields[5].offset, methodDef.fields[5].size);
if ((peImage.readByte(rva) & 3) == 2) {
dm.mhFlags = 2;
dm.mhMaxStack = 8;
dm.mhCodeSize = (uint)dm.code.Length;
dm.mhLocalVarSigTok = 0;
}
else {
dm.mhFlags = peImage.readUInt16(rva);
dm.mhMaxStack = peImage.readUInt16(rva + 2);
dm.mhCodeSize = (uint)dm.code.Length;
dm.mhLocalVarSigTok = peImage.readUInt32(rva + 8);
}
dumpedMethods[dm.token] = dm;
}
}
return true;
}
DumpedMethods createDumpedMethods(PeImage peImage, byte[] fileData, byte[] methodsData)
{
var dumpedMethods = new DumpedMethods();
var methodsDataReader = new BinaryReader(new MemoryStream(methodsData));
var fileDataReader = new BinaryReader(new MemoryStream(fileData));
var metadataTables = peImage.Cor20Header.createMetadataTables();
var methodDef = metadataTables.getMetadataType(MetadataIndex.iMethodDef);
uint methodDefOffset = methodDef.fileOffset;
for (int i = 0; i < methodDef.rows; i++, methodDefOffset += methodDef.totalSize) {
uint bodyRva = peImage.offsetReadUInt32(methodDefOffset);
if (bodyRva == 0)
continue;
uint bodyOffset = peImage.rvaToOffset(bodyRva);
var dm = new DumpedMethod();
dm.token = (uint)(0x06000001 + i);
dm.mdImplFlags = peImage.offsetReadUInt16(methodDefOffset + (uint)methodDef.fields[1].offset);
dm.mdFlags = peImage.offsetReadUInt16(methodDefOffset + (uint)methodDef.fields[2].offset);
dm.mdName = peImage.offsetRead(methodDefOffset + (uint)methodDef.fields[3].offset, methodDef.fields[3].size);
dm.mdSignature = peImage.offsetRead(methodDefOffset + (uint)methodDef.fields[4].offset, methodDef.fields[4].size);
dm.mdParamList = peImage.offsetRead(methodDefOffset + (uint)methodDef.fields[5].offset, methodDef.fields[5].size);
byte b = peImage.offsetReadByte(bodyOffset);
uint codeOffset;
if ((b & 3) == 2) {
if (b != 2)
continue; // not zero byte code size
dm.mhFlags = 2;
dm.mhMaxStack = 8;
dm.mhLocalVarSigTok = 0;
codeOffset = bodyOffset + 1;
}
else {
if (peImage.offsetReadUInt32(bodyOffset + 4) != 0)
continue; // not zero byte code size
dm.mhFlags = peImage.offsetReadUInt16(bodyOffset);
dm.mhMaxStack = peImage.offsetReadUInt16(bodyOffset + 2);
dm.mhLocalVarSigTok = peImage.offsetReadUInt32(bodyOffset + 8);
codeOffset = bodyOffset + (uint)(dm.mhFlags >> 12) * 4;
}
fileDataReader.BaseStream.Position = codeOffset;
if (!decrypter.decrypt(fileDataReader, dm))
continue;
dumpedMethods.add(dm);
}
return dumpedMethods;
}
static void clearDllBit(byte[] peImageData)
{
var mainPeImage = new PeImage(peImageData);
uint characteristicsOffset = mainPeImage.FileHeaderOffset + 18;
ushort characteristics = mainPeImage.offsetReadUInt16(characteristicsOffset);
characteristics &= 0xDFFF;
characteristics |= 2;
mainPeImage.offsetWriteUInt16(characteristicsOffset, characteristics);
}
public bool decrypt(PeImage peImage, ref DumpedMethods dumpedMethods)
{
this.peImage = peImage;
uint offset = peImage.rvaToOffset(peImage.Cor20Header.metadataDirectory.virtualAddress + peImage.Cor20Header.metadataDirectory.size);
if (!readCodeHeader(offset))
return false;
var metadataTables = peImage.Cor20Header.createMetadataTables();
var methodDefTable = metadataTables.getMetadataType(PE.MetadataIndex.iMethodDef);
if (methodDefTable.totalSize != codeHeader.methodDefElemSize)
return false;
var methodInfos = getMethodInfos(offset + 0x30 + codeHeader.totalCodeSize);
offset = methodDefTable.fileOffset - methodDefTable.totalSize;
foreach (var methodInfo in methodInfos) {
offset += methodDefTable.totalSize;
if (methodInfo.flags == 0 || methodInfo.codeOffs == 0)
continue;
uint rva = peImage.offsetReadUInt32(offset);
peImage.writeUint16(rva, (ushort)methodInfo.flags);
peImage.writeUint32(rva + 8, methodInfo.localVarSigTok);
}
dumpedMethods = new DumpedMethods();
offset = methodDefTable.fileOffset;
for (int i = 0; i < methodInfos.Count; i++, offset += methodDefTable.totalSize) {
var methodInfo = methodInfos[i];
if (methodInfo.codeOffs == 0)
continue;
var dm = new DumpedMethod();
dm.token = 0x06000001 + (uint)i;
uint rva = peImage.offsetReadUInt32(offset);
dm.mdImplFlags = peImage.offsetReadUInt16(offset + (uint)methodDefTable.fields[1].offset);
dm.mdFlags = peImage.offsetReadUInt16(offset + (uint)methodDefTable.fields[2].offset);
dm.mdName = peImage.offsetRead(offset + (uint)methodDefTable.fields[3].offset, methodDefTable.fields[3].size);
dm.mdSignature = peImage.offsetRead(offset + (uint)methodDefTable.fields[4].offset, methodDefTable.fields[4].size);
dm.mdParamList = peImage.offsetRead(offset + (uint)methodDefTable.fields[5].offset, methodDefTable.fields[5].size);
dm.code = decrypter.decrypt(methodInfo);
if ((peImage.readByte(rva) & 3) == 2) {
dm.mhFlags = 2;
dm.mhMaxStack = 8;
dm.mhCodeSize = (uint)dm.code.Length;
dm.mhLocalVarSigTok = 0;
}
else {
dm.mhFlags = peImage.readUInt16(rva);
dm.mhMaxStack = peImage.readUInt16(rva + 2);
dm.mhCodeSize = (uint)dm.code.Length;
dm.mhLocalVarSigTok = peImage.readUInt32(rva + 8);
}
dumpedMethods.add(dm);
}
return true;
}
DumpedMethods decryptMethods(PeImage peImage, PeHeader peHeader, McHeader mcHeader)
{
var dumpedMethods = new DumpedMethods();
var methodInfos = new MethodInfos(mainType, peImage, peHeader, mcHeader);
methodInfos.initializeInfos();
var metadataTables = peImage.Cor20Header.createMetadataTables();
var methodDef = metadataTables.getMetadataType(MetadataIndex.iMethodDef);
uint methodDefOffset = methodDef.fileOffset;
for (int i = 0; i < methodDef.rows; i++, methodDefOffset += methodDef.totalSize) {
uint bodyRva = peImage.offsetReadUInt32(methodDefOffset);
if (bodyRva == 0)
continue;
var info = methodInfos.lookup(bodyRva);
if (info == null)
continue;
uint bodyOffset = peImage.rvaToOffset(bodyRva);
ushort magic = peImage.offsetReadUInt16(bodyOffset);
if (magic != 0xFFF3)
continue;
var dm = new DumpedMethod();
dm.token = (uint)(0x06000001 + i);
dm.mdImplFlags = peImage.offsetReadUInt16(methodDefOffset + (uint)methodDef.fields[1].offset);
dm.mdFlags = peImage.offsetReadUInt16(methodDefOffset + (uint)methodDef.fields[2].offset);
dm.mdName = peImage.offsetRead(methodDefOffset + (uint)methodDef.fields[3].offset, methodDef.fields[3].size);
dm.mdSignature = peImage.offsetRead(methodDefOffset + (uint)methodDef.fields[4].offset, methodDef.fields[4].size);
dm.mdParamList = peImage.offsetRead(methodDefOffset + (uint)methodDef.fields[5].offset, methodDef.fields[5].size);
var reader = new BinaryReader(new MemoryStream(info.body));
byte b = reader.ReadByte();
if ((b & 3) == 2) {
dm.mhFlags = 2;
dm.mhMaxStack = 8;
dm.mhCodeSize = (uint)(b >> 2);
dm.mhLocalVarSigTok = 0;
}
else {
reader.BaseStream.Position--;
dm.mhFlags = reader.ReadUInt16();
dm.mhMaxStack = reader.ReadUInt16();
dm.mhCodeSize = reader.ReadUInt32();
dm.mhLocalVarSigTok = reader.ReadUInt32();
uint codeOffset = (uint)(dm.mhFlags >> 12) * 4;
reader.BaseStream.Position += codeOffset - 12;
}
dm.code = reader.ReadBytes((int)dm.mhCodeSize);
if ((dm.mhFlags & 8) != 0) {
reader.BaseStream.Position = (reader.BaseStream.Position + 3) & ~3;
dm.extraSections = reader.ReadBytes((int)(reader.BaseStream.Length - reader.BaseStream.Position));
}
dumpedMethods.add(dm);
}
return dumpedMethods;
}
