/// <summary>
/// Writes the PFS image to the given stream
/// </summary>
public void WriteImage(Stream stream)
{
WriteData(stream);
if (hdr.Mode.HasFlag(PfsMode.Signed))
{
Log("Signing...");
var signKey = Crypto.PfsGenSignKey(properties.EKPFS, hdr.Seed);
foreach (var sig in data_sigs.Concat(final_sigs))
{
var sig_buffer = new byte[sig.Size];
stream.Position = sig.Block * properties.BlockSize;
stream.Read(sig_buffer, 0, sig.Size);
stream.Position = sig.SigOffset;
stream.Write(Crypto.HmacSha256(signKey, sig_buffer), 0, 32);
stream.WriteLE((int)sig.Block);
}
}
if (hdr.Mode.HasFlag(PfsMode.Encrypted))
{
Log("Encrypting...");
var(tweakKey, dataKey) = Crypto.PfsGenEncKey(properties.EKPFS, hdr.Seed);
var transformer = new XtsBlockTransform(dataKey, tweakKey);
byte[] sectorBuffer = new byte[xtsSectorSize];
foreach (var xtsSector in XtsSectorGen())
{
stream.Position = xtsSector * xtsSectorSize;
stream.Read(sectorBuffer, 0, xtsSectorSize);
transformer.EncryptSector(sectorBuffer, (ulong)xtsSector);
stream.Position = xtsSector * xtsSectorSize;
stream.Write(sectorBuffer, 0, xtsSectorSize);
}
}
}
public void TestRoundTrip()
{
byte[] dataKey = new byte[16];
byte[] tweakKey = new byte[16];
var transformer = new XtsBlockTransform(dataKey, tweakKey);
byte[] data = new byte[]
{
0x0, 0x1, 0x2, 0x3, 0x4, 0x5, 0x6, 0x7, 0x8, 0x9, 0xA, 0xB, 0xC, 0xD, 0xE, 0xF,
0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17, 0x18, 0x19, 0x1A, 0x1B, 0x1C, 0x1D, 0x1E, 0x1F,
};
byte[] expected = data.ToArray();
transformer.EncryptSector(data, 0);
CollectionAssert.AreNotEqual(expected, data);
transformer.DecryptSector(data, 0);
CollectionAssert.AreEqual(expected, data);
transformer.EncryptSector(data, 1);
CollectionAssert.AreNotEqual(expected, data);
transformer.DecryptSector(data, 1);
CollectionAssert.AreEqual(expected, data);
}
public void WriteImage(Stream stream)
{
Log("Writing header...");
hdr.WriteToStream(stream);
Log("Writing inodes...");
WriteInodes(stream);
Log("Writing superroot dirents");
WriteSuperrootDirents(stream);
var fpt_file = new FSFile(s => fpt.WriteToStream(s), "flat_path_table", fpt.Size);
fpt_file.ino = fpt_ino;
allNodes.Insert(0, fpt_file);
Log("Writing data blocks...");
for (var x = 0; x < allNodes.Count; x++)
{
var f = allNodes[x];
stream.Position = f.ino.StartBlock * hdr.BlockSize;
WriteFSNode(stream, f);
}
stream.SetLength(hdr.Ndblock * hdr.BlockSize);
if (hdr.Mode.HasFlag(PfsMode.Signed))
{
Log("Signing...");
var signKey = Crypto.PfsGenSignKey(properties.EKPFS, hdr.Seed);
foreach (var sig in sig_order)
{
var sig_buffer = new byte[sig.Size];
stream.Position = sig.Block * properties.BlockSize;
stream.Read(sig_buffer, 0, sig.Size);
stream.Position = sig.SigOffset;
stream.Write(Crypto.HmacSha256(signKey, sig_buffer), 0, 32);
stream.WriteLE((int)sig.Block);
}
}
if (hdr.Mode.HasFlag(PfsMode.Encrypted))
{
Log("Encrypting...");
var encKey = Crypto.PfsGenEncKey(properties.EKPFS, hdr.Seed);
var dataKey = new byte[16];
var tweakKey = new byte[16];
Buffer.BlockCopy(encKey, 0, tweakKey, 0, 16);
Buffer.BlockCopy(encKey, 16, dataKey, 0, 16);
stream.Position = hdr.BlockSize;
var transformer = new XtsBlockTransform(dataKey, tweakKey);
const int sectorSize = 0x1000;
long xtsSector = 16;
long totalSectors = (stream.Length + 0xFFF) / sectorSize;
byte[] sectorBuffer = new byte[sectorSize];
while (xtsSector < totalSectors)
{
if (xtsSector / 0x10 == emptyBlock)
{
xtsSector += 16;
}
stream.Position = xtsSector * sectorSize;
stream.Read(sectorBuffer, 0, sectorSize);
transformer.EncryptSector(sectorBuffer, (ulong)xtsSector);
stream.Position = xtsSector * sectorSize;
stream.Write(sectorBuffer, 0, sectorSize);
xtsSector += 1;
}
}
}