internal SSHPacket ReadMessage()
{
lock (kexlock)
{
try
{
SSHPacket packet = GetSSHPacket(false);
packet.ReadFromStream(transport.GetStream(), incomingCipherLength);
// Mark the current position so we can read more data
packet.Mark();
packet.MoveToPosition(0);
// Decrypt the data if we have a valid cipher
if (decryption != null)
{
decryption.Transform(packet.Array, 0, packet.Array, 0, incomingCipherLength);
}
int msglen = (int)packet.ReadUINT32();
int padlen = packet.ReadByte();
int remaining = (msglen - (incomingCipherLength - 4));
// Verify that the packet length is good
if (remaining < 0)
{
InternalDisconnect();
throw new SSHException("EOF whilst reading message data block", SSHException.UNEXPECTED_TERMINATION);
}
else if (remaining > packet.Limit - packet.Length)
{
InternalDisconnect();
throw new SSHException("Incoming packet length violates SSH protocol",
SSHException.UNEXPECTED_TERMINATION);
}
// Read, decrypt and save the remaining data
packet.MoveToMark();
packet.ReadFromStream(transport.GetStream(), remaining);
if (decryption != null)
{
decryption.Transform(packet.Array, incomingCipherLength, packet.Array, incomingCipherLength, remaining);
}
// Tell the packet where the payload ends
//packet.PayloadLength = (int)msglen - padlen - 1;
if (incomingMac != null)
{
packet.ReadFromStream(transport.GetStream(), incomingMacLength);
// Verify the mac
if (!incomingMac.Verify(incomingSequence, packet.Array, 0, incomingCipherLength + remaining,
packet.Array, incomingCipherLength + remaining))
{
Disconnect("Corrupt Mac on input", DisconnectionReason.MAC_ERROR);
throw new SSHException("Corrupt Mac on input", SSHException.PROTOCOL_VIOLATION);
}
}
if (++incomingSequence > 4294967295)
{
incomingSequence = 0;
}
incomingBytes += incomingCipherLength + remaining + incomingMacLength;
// Uncompress the message payload if necersary
/*if (incomingCompression != null)
* {
* return incomingCompression.uncompress(payload, 0, payload.Length);
* }*/
numIncomingBytesSinceKEX += (uint)packet.Length;
numIncomingSSHPacketsSinceKEX++;
if (numIncomingBytesSinceKEX >= MAX_NUM_BYTES_BEFORE_REKEY ||
numIncomingSSHPacketsSinceKEX >= MAX_NUM_PACKETS_BEFORE_REKEY)
{
SendKeyExchangeInit();
}
// Get the packet ready for reading
packet.MoveToPosition(6);
return(packet);
}
catch (System.ObjectDisposedException ex)
{
InternalDisconnect();
throw new SSHException("Unexpected terminaton: " + ex.Message,
SSHException.UNEXPECTED_TERMINATION);
}
catch (System.IO.IOException ex)
{
InternalDisconnect();
throw new SSHException("Unexpected terminaton: "
+ (ex.Message != null? ex.Message:ex.GetType().FullName)
+ " sequenceNo = " + incomingSequence + " bytesIn = "
+ incomingBytes + " bytesOut = " + outgoingBytes,
SSHException.UNEXPECTED_TERMINATION);
}
}
}