bool CompareFields(ItemField x, Item that, ItemField y)
{
if (x.Length != y.Length)
{
Debug.WriteLine($"Field lengths mismatched ('{x.Type}, {x.Length}', '{y.Type}, {y.Length}')");
return(false);
}
if (x.Type != y.Type)
{
Debug.WriteLine($"Field types mismatched ('{x.Type}', '{y.Type}')");
return(false);
}
var a = GetField(x);
var b = that.GetField(y);
var result = a.SequenceEqual(b);
#if DEBUG
if (!result)
{
Debug.WriteLine($"Fields {x.Type} mismatched ('{string.Join(",", a)}', '{string.Join(", ", b)}')");
}
#endif
PwsUtil.TrashMemory(a);
PwsUtil.TrashMemory(b);
return(result);
}
internal byte[] Get(BlowFish bf)
{
if (_length == 0)
{
return(new byte[0]);
}
// we have data to decrypt
var result = new byte[_length];
var decrypted = bf.Decrypt_ECB(_data);
Array.Copy(decrypted, result, _length);
PwsUtil.TrashMemory(decrypted);
return(result);
}
private async Task WriteCbcInternalAsync(byte[] buffer, int bufferIdx, int length, ICryptoTransform algorithm)
{
var bs = algorithm.OutputBlockSize;
var block1 = new byte[16];
var curblock = block1;
try
{
using (var rng = RandomNumberGenerator.Create())
{
rng.GetBytes(curblock);
if (length > 0 ||
bs == 8 && length == 0) // This part for bwd compat w/pre-3 format)
{
var blockLength = (length + (bs - 1)) / bs * bs;
if (blockLength == 0 && bs == 8)
{
blockLength = bs;
}
// Now, encrypt and write the (rest of the) buffer
for (var x = 0; x < blockLength; x += bs)
{
if (length == 0 || length % bs != 0 && length - x < bs)
{
//This is for an uneven last block
rng.GetBytes(curblock);
Array.Copy(buffer, bufferIdx + x, curblock, 0, length % bs);
}
else
{
Array.Copy(buffer, bufferIdx + x, curblock, 0, bs);
}
XorArray(curblock, Ipthing, bs);
algorithm.TransformBlock(curblock, 0, 16, curblock, 0);
Array.Copy(curblock, Ipthing, bs);
await _stream.WriteAsync(curblock, 0, bs);
}
}
}
}
finally
{
PwsUtil.TrashMemory(curblock);
}
}
private async Task WriteCbcInternalAsync(byte type, byte[] buffer, int length, ICryptoTransform algorithm)
{
var bs = algorithm.OutputBlockSize;
var block1 = new byte[16];
var curblock = block1;
try
{
var bufferIdx = 0;
using (var rng = RandomNumberGenerator.Create())
{
rng.GetBytes(curblock);
}
// block length overwrites 4 bytes of the above randomness.
var len = BitConverter.GetBytes(length);
Array.Copy(len, curblock, len.Length);
// following new for format 2.0 - lengthblock bytes 4-7 were unused before.
curblock[sizeof(int)] = type;
if (bs == 16)
{
// In this case, we've too many (11) wasted bytes in the length block
// So we store actual data there:
// (11 = BlockSize - 4 (length) - 1 (type)
var len1 = length > 11 ? 11 : length;
Array.Copy(buffer, 0, curblock, 5, len1);
length -= len1;
bufferIdx += len1;
}
XorArray(curblock, Ipthing, bs); // do the CBC thing
algorithm.TransformBlock(curblock, 0, 16, curblock, 0);
Array.Copy(curblock, Ipthing, bs); // update CBC for next round
await _stream.WriteAsync(curblock, 0, bs);
await WriteCbcInternalAsync(buffer, bufferIdx, length, algorithm);
}
finally
{
PwsUtil.TrashMemory(curblock);
}
}
/*
* Reads an encrypted record into buffer.
* The first block of the record contains the encrypted record length
* We have the usual ugly problem of fixed buffer lengths in C/C++.
* allocate the buffer here, to ensure that it's long enough.
* *** THE CALLER MUST delete[] IT AFTER USE *** UGH++
*
* (unless buffer_len is zero)
*
* Note that the buffer is a byte array, and buffer_len is number of
* bytes. This means that any data can be passed, and we don't
* care at this level if strings are char or wchar_t.
*
* If TERMINAL_BLOCK is non-NULL, the first block read is tested against it,
* and -1 is returned if it matches. (used in V3)
*/
private async Task <PwsRecord> ReadCbcInternalAsync(ICryptoTransform algorithm,
byte[] terminalBlock)
{
var bs = algorithm.InputBlockSize;
var block1 = new byte[16];
var block2 = new byte[16];
var block3 = new byte[16];
var lengthblock = block1;
var numRead = await _stream.ReadAsync(lengthblock, 0, bs);
if (numRead != bs)
{
return(null);
}
if (terminalBlock != null && lengthblock.SequenceEqual(terminalBlock))
{
return(null);
}
var lcpy = block2;
Array.Copy(lengthblock, lcpy, bs);
algorithm.TransformBlock(lengthblock, 0, lengthblock.Length, lengthblock, 0);
XorArray(lengthblock, Ipthing, bs);
Array.Copy(lcpy, Ipthing, bs);
var length = BitConverter.ToUInt32(lengthblock, 0);
var result = new PwsRecord();
// new for 2.0 -- lengthblock[4..7] previously set to zero
result.Type = lengthblock[sizeof(int)]; // type is first byte after the length
if (_stream.Length != 0 && length >= _stream.Length)
{
PwsUtil.TrashMemory(lengthblock);
return(null);
}
var bufferLen = length;
var buffer = new byte[length / bs * bs + 2 * bs]; // round upwards
var bufferidx = 0;
if (bs == 16)
{
// length block contains up to 11 (= 16 - 4 - 1) bytes
// of data
var len1 = length > 11 ? 11 : length;
Array.Copy(lengthblock, 5, buffer, bufferidx, (int)len1);
length -= len1;
bufferidx += (int)len1;
}
var blockLength = (length + (bs - 1)) / bs * bs;
// Following is meant for lengths < BS,
// but results in a block being read even
// if length is zero. This is wasteful,
// but fixing it would break all existing pre-3.0 databases.
if (blockLength == 0 && bs == 8)
{
blockLength = bs;
}
PwsUtil.TrashMemory(lengthblock);
if (length > 0 || bs == 8 && length == 0)
{
// pre-3 pain
var tempcbc = block3;
numRead += await _stream.ReadAsync(buffer, bufferidx, (int)blockLength);
for (var x = 0; x < blockLength; x += bs)
{
Array.Copy(buffer, bufferidx + x, tempcbc, 0, bs);
algorithm.TransformBlock(buffer, bufferidx + x, 16, buffer, bufferidx + x);
XorArray(buffer, bufferidx + x, Ipthing, 0, bs);
Array.Copy(tempcbc, Ipthing, bs);
}
}
if (bufferLen == 0)
{
result.Buffer = new byte[0];
}
else
{
result.Buffer = new byte[bufferLen];
Array.Copy(buffer, result.Buffer, (int)bufferLen);
PwsUtil.TrashMemory(buffer);
}
result.ReadBytes = numRead;
return(result);
}
