private AuthenticationResult ProcessAuthenticationResponse()
{
do {
SSH2DataReader response = new SSH2DataReader(ReceivePacket().Data);
PacketType h = response.ReadPacketType();
if(h==PacketType.SSH_MSG_USERAUTH_FAILURE) {
string msg = Encoding.ASCII.GetString(response.ReadString());
return AuthenticationResult.Failure;
}
else if(h==PacketType.SSH_MSG_USERAUTH_BANNER) {
Debug.WriteLine("USERAUTH_BANNER");
}
else if(h==PacketType.SSH_MSG_USERAUTH_SUCCESS) {
_packetBuilder.Handler = new CallbackSSH2PacketHandler(this);
return AuthenticationResult.Success; //successfully exit
}
else if(h==PacketType.SSH_MSG_USERAUTH_INFO_REQUEST) {
string name = Encoding.ASCII.GetString(response.ReadString());
string inst = Encoding.ASCII.GetString(response.ReadString());
string lang = Encoding.ASCII.GetString(response.ReadString());
int num = response.ReadInt32();
string[] prompts = new string[num];
for(int i=0; i<num; i++) {
prompts[i] = Encoding.ASCII.GetString(response.ReadString());
bool echo = response.ReadBool();
}
_eventReceiver.OnAuthenticationPrompt(prompts);
return AuthenticationResult.Prompt;
}
else
throw new SSHException("protocol error: unexpected packet type "+h);
} while(true);
}
internal void ProcessPacket(ISSHChannelEventReceiver receiver, PacketType pt, int data_length, SSH2DataReader re)
{
//NOTE: the offset of 're' is next to 'receipiant channel' field
_leftWindowSize -= data_length;
if(pt!=PacketType.SSH_MSG_CHANNEL_EOF && pt!=PacketType.SSH_MSG_CHANNEL_CLOSE) { //window adjust is not necessary if the channel is being closed
while(_leftWindowSize <= _windowSize) {
SSH2DataWriter adj = new SSH2DataWriter();
adj.WritePacketType(PacketType.SSH_MSG_CHANNEL_WINDOW_ADJUST);
adj.Write(_remoteID);
adj.Write(_windowSize);
TransmitPacket(adj.ToByteArray());
_leftWindowSize += _windowSize;
//Debug.WriteLine("Window size is adjusted to " + _leftWindowSize);
}
}
if(pt==PacketType.SSH_MSG_CHANNEL_WINDOW_ADJUST) {
int w = re.ReadInt32();
//some servers may not send SSH_MSG_CHANNEL_WINDOW_ADJUST.
//it is dangerous to wait this message in send procedure
_allowedDataSize += w;
//Debug.WriteLine(String.Format("Window Adjust +={0}",w));
}
else if(_negotiationStatus!=0) { //when the negotiation is not completed
if(_type==ChannelType.Shell)
OpenShell(receiver, pt, re);
else if(_type==ChannelType.ForwardedLocalToRemote)
ReceivePortForwardingResponse(receiver, pt, re);
else if(_type==ChannelType.Session)
EstablishSession(receiver, pt, re);
}
else {
switch(pt) {
case PacketType.SSH_MSG_CHANNEL_DATA: {
int len = re.ReadInt32();
receiver.OnData(re.Image, re.Offset, len);
}
break;
case PacketType.SSH_MSG_CHANNEL_EXTENDED_DATA: {
int t = re.ReadInt32();
byte[] data = re.ReadString();
receiver.OnExtendedData(t, data);
}
break;
case PacketType.SSH_MSG_CHANNEL_REQUEST: {
string request = Encoding.ASCII.GetString(re.ReadString());
bool reply = re.ReadBool();
if(request=="exit-status") {
int status = re.ReadInt32();
}
else if(reply) { //we reject unknown requests including keep-alive check
SSH2DataWriter wr = new SSH2DataWriter();
wr.WritePacketType(PacketType.SSH_MSG_CHANNEL_FAILURE);
wr.Write(_remoteID);
TransmitPacket(wr.ToByteArray());
}
}
break;
case PacketType.SSH_MSG_CHANNEL_EOF:
receiver.OnChannelEOF();
break;
case PacketType.SSH_MSG_CHANNEL_CLOSE:
_connection.UnregisterChannelEventReceiver(_localID);
receiver.OnChannelClosed();
break;
case PacketType.SSH_MSG_CHANNEL_FAILURE:
case PacketType.SSH_MSG_CHANNEL_SUCCESS:
receiver.OnMiscPacket((byte)pt, re.Image, re.Offset, re.Rest);
break;
default:
receiver.OnMiscPacket((byte)pt, re.Image, re.Offset, re.Rest);
Debug.WriteLine("Unknown Packet "+pt);
break;
}
}
}
//synchronous reception
internal SSH2Packet ReceivePacket()
{
while(true) {
SSH2Packet p = null;
SynchronizedSSH2PacketHandler handler = (SynchronizedSSH2PacketHandler)_packetBuilder.Handler;
if(!handler.HasPacket) {
handler.Wait();
if(handler.State==ReceiverState.Error)
throw new SSHException(handler.ErrorMessage);
else if(handler.State==ReceiverState.Closed)
throw new SSHException("socket closed");
}
p = handler.PopPacket();
SSH2DataReader r = new SSH2DataReader(p.Data);
PacketType pt = r.ReadPacketType();
if(pt==PacketType.SSH_MSG_IGNORE) {
if(_eventReceiver!=null) _eventReceiver.OnIgnoreMessage(r.ReadString());
}
else if(pt==PacketType.SSH_MSG_DEBUG) {
bool f = r.ReadBool();
if(_eventReceiver!=null) _eventReceiver.OnDebugMessage(f, r.ReadString());
}
else
return p;
}
}
private void ProcessKEXINIT(SSH2Packet packet)
{
_serverKEXINITPayload = packet.Data;
SSH2DataReader re = new SSH2DataReader(_serverKEXINITPayload);
byte[] head = re.Read(17); //Type and cookie
if(head[0]!=(byte)PacketType.SSH_MSG_KEXINIT) throw new SSHException(String.Format("Server response is not SSH_MSG_KEXINIT but {0}", head[0]));
Encoding enc = Encoding.ASCII;
string kex = enc.GetString(re.ReadString());
_cInfo._supportedKEXAlgorithms = kex;
CheckAlgorithmSupport("keyexchange", kex, "diffie-hellman-group1-sha1");
string host_key = enc.GetString(re.ReadString());
_cInfo._supportedHostKeyAlgorithms = host_key;
_cInfo._algorithmForHostKeyVerification = DecideHostKeyAlgorithm(host_key);
string enc_cs = enc.GetString(re.ReadString());
_cInfo._supportedCipherAlgorithms = enc_cs;
_cInfo._algorithmForTransmittion = DecideCipherAlgorithm(enc_cs);
string enc_sc = enc.GetString(re.ReadString());
_cInfo._algorithmForReception = DecideCipherAlgorithm(enc_sc);
string mac_cs = enc.GetString(re.ReadString());
CheckAlgorithmSupport("mac", mac_cs, "hmac-sha1");
string mac_sc = enc.GetString(re.ReadString());
CheckAlgorithmSupport("mac", mac_sc, "hmac-sha1");
string comp_cs = enc.GetString(re.ReadString());
CheckAlgorithmSupport("compression", comp_cs, "none");
string comp_sc = enc.GetString(re.ReadString());
CheckAlgorithmSupport("compression", comp_sc, "none");
string lang_cs = enc.GetString(re.ReadString());
string lang_sc = enc.GetString(re.ReadString());
bool flag = re.ReadBool();
int reserved = re.ReadInt32();
Debug.Assert(re.Rest==0);
if(flag) throw new SSHException("Algorithm negotiation failed");
}