// Derived class can override this method to modify the buffer.
public virtual DataFragment Close(Cipher cipher, MAC mac, int sequence)
{
if (!_isOpen)
{
throw new SSHException("internal state error");
}
int blocksize = cipher == null ? 8 : cipher.BlockSize;
int payloadLength = _writer.Length - (SEQUENCE_MARGIN + LENGTH_MARGIN + PADDING_MARGIN);
int paddingLength = 11 - payloadLength % blocksize;
while (paddingLength < 4)
{
paddingLength += blocksize;
}
int packetLength = PADDING_MARGIN + payloadLength + paddingLength;
int imageLength = packetLength + LENGTH_MARGIN;
//fill padding
byte[] tmp = new byte[4];
Rng rng = RngManager.GetSecureRng();
for (int i = 0; i < paddingLength; i += 4)
{
rng.GetBytes(tmp);
_writer.Write(tmp);
}
//manipulate stream
byte[] rawbuf = _writer.UnderlyingBuffer;
SSHUtil.WriteIntToByteArray(rawbuf, 0, sequence);
SSHUtil.WriteIntToByteArray(rawbuf, SEQUENCE_MARGIN, packetLength);
rawbuf[SEQUENCE_MARGIN + LENGTH_MARGIN] = (byte)paddingLength;
//mac
if (mac != null)
{
byte[] macCode = mac.ComputeHash(rawbuf, 0, packetLength + LENGTH_MARGIN + SEQUENCE_MARGIN);
Array.Copy(macCode, 0, rawbuf, packetLength + LENGTH_MARGIN + SEQUENCE_MARGIN, macCode.Length);
imageLength += macCode.Length;
}
//encrypt
if (cipher != null)
{
cipher.Encrypt(rawbuf, SEQUENCE_MARGIN, packetLength + LENGTH_MARGIN, rawbuf, SEQUENCE_MARGIN);
}
_dataFragment.Init(rawbuf, SEQUENCE_MARGIN, imageLength);
_isOpen = false;
return(_dataFragment);
}
public void Close(Cipher cipher, Random rnd, MAC mac, int sequence, DataFragment result)
{
if (!_is_open)
{
throw new SSHException("internal state error");
}
int blocksize = cipher == null? 8 : cipher.BlockSize;
int payload_length = _writer.Length - (SEQUENCE_MARGIN + LENGTH_MARGIN + PADDING_MARGIN);
int r = 11 - payload_length % blocksize;
while (r < 4)
{
r += blocksize;
}
_paddingLength = r;
_packetLength = PADDING_MARGIN + payload_length + _paddingLength;
int image_length = _packetLength + LENGTH_MARGIN;
//fill padding
for (int i = 0; i < _paddingLength; i += 4)
{
_writer.Write(rnd.Next());
}
//manipulate stream
byte[] rawbuf = _writer.UnderlyingBuffer;
SSHUtil.WriteIntToByteArray(rawbuf, 0, sequence);
SSHUtil.WriteIntToByteArray(rawbuf, SEQUENCE_MARGIN, _packetLength);
rawbuf[SEQUENCE_MARGIN + LENGTH_MARGIN] = (byte)_paddingLength;
//mac
if (mac != null)
{
_mac = mac.ComputeHash(rawbuf, 0, _packetLength + LENGTH_MARGIN + SEQUENCE_MARGIN);
Array.Copy(_mac, 0, rawbuf, _packetLength + LENGTH_MARGIN + SEQUENCE_MARGIN, _mac.Length);
image_length += _mac.Length;
}
//encrypt
if (cipher != null)
{
cipher.Encrypt(rawbuf, SEQUENCE_MARGIN, _packetLength + LENGTH_MARGIN, rawbuf, SEQUENCE_MARGIN);
}
result.Init(rawbuf, SEQUENCE_MARGIN, image_length);
_is_open = false;
}
