// sending "exec" service for SCP protocol.
private void ExecCommand(ISSHChannelEventReceiver receiver, PacketType pt, SSH2DataReader reader) {
if(_negotiationStatus==NegotiationStatus.WaitingChannelConfirmation) {
if(pt!=PacketType.SSH_MSG_CHANNEL_OPEN_CONFIRMATION) {
if(pt!=PacketType.SSH_MSG_CHANNEL_OPEN_FAILURE)
receiver.OnChannelError(new SSHException("opening channel failed; packet type="+pt));
else {
int errcode = reader.ReadInt32();
string msg = Encoding.ASCII.GetString(reader.ReadString());
receiver.OnChannelError(new SSHException(msg));
}
Close();
}
else {
_remoteID = reader.ReadInt32();
_allowedDataSize = reader.ReadInt32();
_serverMaxPacketSize = reader.ReadInt32();
// exec command
SSH2DataWriter wr = new SSH2DataWriter();
SSHConnectionParameter param = _connection.Param;
wr.WritePacketType(PacketType.SSH_MSG_CHANNEL_REQUEST);
wr.Write(_remoteID);
wr.Write("exec"); // "exec"
wr.Write(false); // want confirm is disabled. (*)
wr.Write(_command);
if (_connection.IsEventTracerAvailable)
_connection.TraceTransmissionEvent("exec command","cmd={0}", _command);
TransmitPayload(wr.ToByteArray());
//confirmation is omitted
receiver.OnChannelReady();
_negotiationStatus = NegotiationStatus.Ready; //goal!
}
}
else if(_negotiationStatus==NegotiationStatus.WaitingExecCmdConfirmation) {
if(pt!=PacketType.SSH_MSG_CHANNEL_DATA) {
receiver.OnChannelError(new SSHException("exec command failed"));
Close();
}
else {
receiver.OnChannelReady();
_negotiationStatus = NegotiationStatus.Ready; //goal!
}
}
else
throw new SSHException("internal state error");
}
private void OpenShellOrSubsystem(ISSHChannelEventReceiver receiver, PacketType pt, SSH2DataReader reader, string scheme) {
if(_negotiationStatus==NegotiationStatus.WaitingChannelConfirmation) {
if(pt!=PacketType.SSH_MSG_CHANNEL_OPEN_CONFIRMATION) {
if(pt!=PacketType.SSH_MSG_CHANNEL_OPEN_FAILURE)
receiver.OnChannelError(new SSHException("opening channel failed; packet type="+pt));
else {
int errcode = reader.ReadInt32();
string msg = Encoding.ASCII.GetString(reader.ReadString());
receiver.OnChannelError(new SSHException(msg));
}
Close();
}
else {
_remoteID = reader.ReadInt32();
_allowedDataSize = reader.ReadInt32();
_serverMaxPacketSize = reader.ReadInt32();
//open pty
SSH2DataWriter wr = new SSH2DataWriter();
SSHConnectionParameter param = _connection.Param;
wr.WritePacketType(PacketType.SSH_MSG_CHANNEL_REQUEST);
wr.Write(_remoteID);
wr.Write("pty-req");
wr.Write(true);
wr.Write(param.TerminalName);
wr.Write(param.TerminalWidth);
wr.Write(param.TerminalHeight);
wr.Write(param.TerminalPixelWidth);
wr.Write(param.TerminalPixelHeight);
wr.WriteAsString(new byte[0]);
if(_connection.IsEventTracerAvailable)
_connection.TraceTransmissionEvent(PacketType.SSH_MSG_CHANNEL_REQUEST, "pty-req", "terminal={0} width={1} height={2}", param.TerminalName, param.TerminalWidth, param.TerminalHeight);
TransmitPayload(wr.ToByteArray());
_negotiationStatus = NegotiationStatus.WaitingPtyReqConfirmation;
}
}
else if(_negotiationStatus==NegotiationStatus.WaitingPtyReqConfirmation) {
if(pt!=PacketType.SSH_MSG_CHANNEL_SUCCESS) {
receiver.OnChannelError(new SSHException("opening pty failed"));
Close();
}
else {
//agent request (optional)
if(_connection.Param.AgentForward!=null) {
SSH2DataWriter wr = new SSH2DataWriter();
wr.WritePacketType(PacketType.SSH_MSG_CHANNEL_REQUEST);
wr.Write(_remoteID);
wr.Write("*****@*****.**");
wr.Write(true);
_connection.TraceTransmissionEvent(PacketType.SSH_MSG_CHANNEL_REQUEST, "auth-agent-req", "");
TransmitPayload(wr.ToByteArray());
_negotiationStatus = NegotiationStatus.WaitingAuthAgentReqConfirmation;
}
else {
OpenScheme(scheme);
_negotiationStatus = NegotiationStatus.WaitingShellConfirmation;
}
}
}
else if(_negotiationStatus==NegotiationStatus.WaitingAuthAgentReqConfirmation) {
if(pt!=PacketType.SSH_MSG_CHANNEL_SUCCESS && pt!=PacketType.SSH_MSG_CHANNEL_FAILURE) {
receiver.OnChannelError(new SSHException("auth-agent-req error"));
Close();
}
else { //auth-agent-req is optional
_connection.SetAgentForwardConfirmed(pt==PacketType.SSH_MSG_CHANNEL_SUCCESS);
_connection.TraceReceptionEvent(pt, "auth-agent-req");
OpenScheme(scheme);
_negotiationStatus = NegotiationStatus.WaitingShellConfirmation;
}
}
else if(_negotiationStatus==NegotiationStatus.WaitingShellConfirmation) {
if(pt!=PacketType.SSH_MSG_CHANNEL_SUCCESS) {
receiver.OnChannelError(new SSHException("Opening shell failed: packet type="+pt.ToString()));
Close();
}
else {
receiver.OnChannelReady();
_negotiationStatus = NegotiationStatus.Ready; //goal!
}
}
}
private void OpenScheme(string scheme) {
//open shell / subsystem
SSH2DataWriter wr = new SSH2DataWriter();
wr.WritePacketType(PacketType.SSH_MSG_CHANNEL_REQUEST);
wr.Write(_remoteID);
wr.Write(scheme);
wr.Write(true);
if(_command!=null)
wr.Write(_command);
TransmitPayload(wr.ToByteArray());
}
private void AdjustWindowSize(PacketType pt, int data_length) {
_leftWindowSize -= data_length;
if(pt==PacketType.SSH_MSG_CHANNEL_EOF || pt==PacketType.SSH_MSG_CHANNEL_CLOSE) return; //window adjust is not necessary if the channel is being closed
// need not send window size to server when the channel is not opened.
if (_negotiationStatus!=NegotiationStatus.Ready) return;
while(_leftWindowSize <= _windowSize) {
SSH2DataWriter adj = new SSH2DataWriter();
adj.WritePacketType(PacketType.SSH_MSG_CHANNEL_WINDOW_ADJUST);
adj.Write(_remoteID);
adj.Write(_windowSize);
TransmitPayload(adj.ToByteArray());
_leftWindowSize += _windowSize;
if(_connection.IsEventTracerAvailable)
_connection.TraceTransmissionEvent("SSH_MSG_CHANNEL_WINDOW_ADJUST", "adjusted to {0} by increasing {1}", _leftWindowSize, _windowSize);
}
}
private void ProcessChannelLocalData(ISSHChannelEventReceiver receiver, PacketType pt, SSH2DataReader re) {
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);
TransmitPayload(wr.ToByteArray());
}
}
break;
case PacketType.SSH_MSG_CHANNEL_EOF:
receiver.OnChannelEOF();
break;
case PacketType.SSH_MSG_CHANNEL_CLOSE:
_connection.ChannelCollection.UnregisterChannelEventReceiver(_localID);
receiver.OnChannelClosed();
break;
case PacketType.SSH_MSG_CHANNEL_FAILURE:
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;
}
}
private void ProcessAgentForwardRequest(ISSHConnectionEventReceiver receiver, SSH2DataReader reader) {
int remote_channel = reader.ReadInt32();
int window_size = reader.ReadInt32(); //skip initial window size
int servermaxpacketsize = reader.ReadInt32();
TraceReceptionEvent("agent forward request", "");
SSH2DataWriter wr = new SSH2DataWriter();
IAgentForward af = _param.AgentForward;
if(_agentForwardConfirmed && af!=null && af.CanAcceptForwarding()) {
//send OPEN_CONFIRMATION
AgentForwardingChannel ch = new AgentForwardingChannel(af);
SSH2Channel channel = new SSH2Channel(this, ChannelType.AgentForward, this.ChannelCollection.RegisterChannelEventReceiver(null, ch).LocalID, remote_channel, servermaxpacketsize);
ch.SetChannel(channel);
wr.WritePacketType(PacketType.SSH_MSG_CHANNEL_OPEN_CONFIRMATION);
wr.Write(remote_channel);
wr.Write(channel.LocalChannelID);
wr.Write(_param.WindowSize); //initial window size
wr.Write(_param.MaxPacketSize); //max packet size
TraceTransmissionEvent("granados confirmed agent-forwarding request", "");
}
else {
wr.WritePacketType(PacketType.SSH_MSG_CHANNEL_OPEN_FAILURE);
wr.Write(remote_channel);
wr.Write(0);
wr.Write("reject");
wr.Write(""); //lang tag
TraceTransmissionEvent("granados rejected agent-forwarding request", "");
}
TransmitRawPayload(wr.ToByteArray());
}
private bool ProcessPacket(DataFragment packet) {
if(_readerForProcessPacket==null)
_readerForProcessPacket = new SSH2DataReader(packet);
else
_readerForProcessPacket.Recycle(packet); //avoid 'new'
SSH2DataReader r = _readerForProcessPacket; //rename for frequently use
PacketType pt = r.ReadPacketType();
if(pt==PacketType.SSH_MSG_DISCONNECT) {
int errorcode = r.ReadInt32();
_eventReceiver.OnConnectionClosed();
return false;
}
else if(_waitingForPortForwardingResponse) {
if(pt!=PacketType.SSH_MSG_REQUEST_SUCCESS)
_eventReceiver.OnUnknownMessage((byte)pt, r.Image);
_waitingForPortForwardingResponse = false;
return true;
}
else if(pt==PacketType.SSH_MSG_CHANNEL_OPEN) {
string method = Encoding.ASCII.GetString(r.ReadString());
if(method=="forwarded-tcpip")
ProcessPortforwardingRequest(_eventReceiver, r);
else if(method.StartsWith("auth-agent")) //in most cases, method is "*****@*****.**"
ProcessAgentForwardRequest(_eventReceiver, r);
else {
SSH2DataWriter wr = new SSH2DataWriter();
wr.WritePacketType(PacketType.SSH_MSG_CHANNEL_OPEN_FAILURE);
wr.Write(r.ReadInt32());
wr.Write(0);
wr.Write("unknown method");
wr.Write(""); //lang tag
TraceReceptionEvent("SSH_MSG_CHANNEL_OPEN rejected", "method={0}", method);
}
return true;
}
else if(pt>=PacketType.SSH_MSG_CHANNEL_OPEN_CONFIRMATION && pt<=PacketType.SSH_MSG_CHANNEL_FAILURE) {
int local_channel = r.ReadInt32();
ChannelCollection.Entry e = this.ChannelCollection.FindChannelEntry(local_channel);
if(e!=null)
((SSH2Channel)e.Channel).ProcessPacket(e.Receiver, pt, 5+r.Rest, r);
else
Debug.WriteLine("unexpected channel pt="+pt+" local_channel="+local_channel.ToString());
return true;
}
else if(pt==PacketType.SSH_MSG_IGNORE) {
_eventReceiver.OnIgnoreMessage(r.ReadString());
return true;
}
else if(_asyncKeyExchanger!=null) {
_asyncKeyExchanger.AsyncProcessPacket(packet);
return true;
}
else if(pt==PacketType.SSH_MSG_KEXINIT) {
//Debug.WriteLine("Host sent KEXINIT");
_asyncKeyExchanger = new KeyExchanger(this, _sessionID);
_asyncKeyExchanger.AsyncProcessPacket(packet);
return true;
}
else {
_eventReceiver.OnUnknownMessage((byte)pt, r.Image);
return false;
}
}
private void ProcessPortforwardingRequest(ISSHConnectionEventReceiver receiver, SSH2DataReader reader) {
int remote_channel = reader.ReadInt32();
int window_size = reader.ReadInt32(); //skip initial window size
int servermaxpacketsize = reader.ReadInt32();
string host = Encoding.ASCII.GetString(reader.ReadString());
int port = reader.ReadInt32();
string originator_ip = Encoding.ASCII.GetString(reader.ReadString());
int originator_port = reader.ReadInt32();
TraceReceptionEvent("port forwarding request", String.Format("host={0} port={1} originator-ip={2} originator-port={3}", host, port, originator_ip, originator_port));
PortForwardingCheckResult r = receiver.CheckPortForwardingRequest(host,port,originator_ip,originator_port);
SSH2DataWriter wr = new SSH2DataWriter();
if(r.allowed) {
//send OPEN_CONFIRMATION
SSH2Channel channel = new SSH2Channel(this, ChannelType.ForwardedRemoteToLocal, this.ChannelCollection.RegisterChannelEventReceiver(null, r.channel).LocalID, remote_channel, servermaxpacketsize);
wr.WritePacketType(PacketType.SSH_MSG_CHANNEL_OPEN_CONFIRMATION);
wr.Write(remote_channel);
wr.Write(channel.LocalChannelID);
wr.Write(_param.WindowSize); //initial window size
wr.Write(_param.MaxPacketSize); //max packet size
receiver.EstablishPortforwarding(r.channel, channel);
TraceTransmissionEvent("port-forwarding request is confirmed", "host={0} port={1} originator-ip={2} originator-port={3}", host, port, originator_ip, originator_port);
}
else {
wr.WritePacketType(PacketType.SSH_MSG_CHANNEL_OPEN_FAILURE);
wr.Write(remote_channel);
wr.Write(r.reason_code);
wr.Write(r.reason_message);
wr.Write(""); //lang tag
TraceTransmissionEvent("port-forwarding request is rejected", "host={0} port={1} originator-ip={2} originator-port={3}", host, port, originator_ip, originator_port);
}
TransmitRawPayload(wr.ToByteArray());
}
private AuthenticationResult UserAuth() {
const string sn = "ssh-connection";
if(_param.AuthenticationType==AuthenticationType.KeyboardInteractive) {
SSH2DataWriter wr = OpenTransmissionPacket();
wr.WritePacketType(PacketType.SSH_MSG_USERAUTH_REQUEST);
wr.Write(_param.UserName);
wr.Write(sn);
wr.Write("keyboard-interactive");
wr.Write(""); //lang
wr.Write(""); //submethod
TraceTransmissionEvent(PacketType.SSH_MSG_USERAUTH_REQUEST, "starting keyboard-interactive authentication");
TransmitPacket(wr);
_authenticationResult = ProcessAuthenticationResponse();
}
else {
SSH2DataWriter wr = OpenTransmissionPacket();
wr.WritePacketType(PacketType.SSH_MSG_USERAUTH_REQUEST);
wr.Write(_param.UserName);
if(_param.AuthenticationType==AuthenticationType.Password) {
//Password authentication
wr.Write(sn);
wr.Write("password");
wr.Write(false);
wr.Write(_param.Password);
TraceTransmissionEvent(PacketType.SSH_MSG_USERAUTH_REQUEST, "starting password authentication");
}
else {
//public key authentication
SSH2UserAuthKey kp = SSH2UserAuthKey.FromSECSHStyleFile(_param.IdentityFile, _param.Password);
SSH2DataWriter signsource = new SSH2DataWriter();
signsource.WriteAsString(_sessionID);
signsource.WritePacketType(PacketType.SSH_MSG_USERAUTH_REQUEST);
signsource.Write(_param.UserName);
signsource.Write(sn);
signsource.Write("publickey");
signsource.Write(true);
signsource.Write(SSH2Util.PublicKeyAlgorithmName(kp.Algorithm));
signsource.WriteAsString(kp.GetPublicKeyBlob());
SSH2DataWriter signpack = new SSH2DataWriter();
signpack.Write(SSH2Util.PublicKeyAlgorithmName(kp.Algorithm));
signpack.WriteAsString(kp.Sign(signsource.ToByteArray()));
wr.Write(sn);
wr.Write("publickey");
wr.Write(true);
wr.Write(SSH2Util.PublicKeyAlgorithmName(kp.Algorithm));
wr.WriteAsString(kp.GetPublicKeyBlob());
wr.WriteAsString(signpack.ToByteArray());
TraceTransmissionEvent(PacketType.SSH_MSG_USERAUTH_REQUEST, "starting public key authentication");
}
TransmitPacket(wr);
_authenticationResult = ProcessAuthenticationResponse();
if(_authenticationResult==AuthenticationResult.Failure)
throw new SSHException(Strings.GetString("AuthenticationFailed"));
}
return _authenticationResult;
}
private void SendKEXINIT(Mode mode) {
const string kex_algorithm = "diffie-hellman-group1-sha1";
const string mac_algorithm = "hmac-sha1";
SSH2DataWriter wr = new SSH2DataWriter();
wr.WritePacketType(PacketType.SSH_MSG_KEXINIT);
byte[] cookie = new byte[16];
_param.Random.NextBytes(cookie);
wr.Write(cookie);
wr.Write(kex_algorithm); // kex_algorithms
wr.Write(FormatHostKeyAlgorithmDescription()); // server_host_key_algorithms
wr.Write(FormatCipherAlgorithmDescription()); // encryption_algorithms_client_to_server
wr.Write(FormatCipherAlgorithmDescription()); // encryption_algorithms_server_to_client
wr.Write(mac_algorithm); // mac_algorithms_client_to_server
wr.Write(mac_algorithm); // mac_algorithms_server_to_client
wr.Write("none"); // compression_algorithms_client_to_server
wr.Write("none"); // compression_algorithms_server_to_client
wr.Write(""); // languages_client_to_server
wr.Write(""); // languages_server_to_client
wr.Write(false); //Indicates whether a guessed key exchange packet follows
wr.Write(0); //reserved for future extension
_clientKEXINITPayload = wr.ToByteArray();
_status = Status.WAIT_KEXINIT;
if(_connection.IsEventTracerAvailable) {
StringBuilder bld = new StringBuilder();
bld.Append("kex_algorithm="); bld.Append(kex_algorithm);
bld.Append("; server_host_key_algorithms="); bld.Append(FormatHostKeyAlgorithmDescription());
bld.Append("; encryption_algorithms_client_to_server="); bld.Append(FormatCipherAlgorithmDescription());
bld.Append("; encryption_algorithms_server_to_client="); bld.Append(FormatCipherAlgorithmDescription());
bld.Append("; mac_algorithms_client_to_server="); bld.Append(mac_algorithm);
bld.Append("; mac_algorithms_server_to_client="); bld.Append(mac_algorithm);
TraceTransmissionNegotiation(PacketType.SSH_MSG_KEXINIT, bld.ToString());
}
TransmitRawPayload(_clientKEXINITPayload);
}
private DataFragment SendKEXDHINIT(Mode mode) {
//Round1 computes and sends [e]
byte[] sx = new byte[16];
_param.Random.NextBytes(sx);
_x = new BigInteger(sx);
_e = new BigInteger(2).modPow(_x, DH_PRIME);
SSH2DataWriter wr = new SSH2DataWriter();
wr.WritePacketType(PacketType.SSH_MSG_KEXDH_INIT);
wr.WriteBigInteger(_e);
_status = Status.WAIT_KEXDH_REPLY;
TraceTransmissionNegotiation(PacketType.SSH_MSG_KEXDH_INIT, "");
if (mode == Mode.Synchronized)
return SynchronizedTransmitRawPayload(wr.ToByteArray());
else {
TransmitRawPayload(wr.ToByteArray());
return null;
}
}
private DataFragment SendKEXDHINIT(Mode mode)
{
//Round1 computes and sends [e]
byte[] sx = new byte[32];
RngManager.GetSecureRng().GetBytes(sx);
_x = new BigInteger(sx);
_e = new BigInteger(2).modPow(_x, GetDiffieHellmanPrime(_cInfo._kexAlgorithm));
SSH2DataWriter wr = new SSH2DataWriter();
wr.WritePacketType(PacketType.SSH_MSG_KEXDH_INIT);
wr.WriteBigInteger(_e);
_status = Status.WAIT_KEXDH_REPLY;
TraceTransmissionNegotiation(PacketType.SSH_MSG_KEXDH_INIT, "");
if (mode == Mode.Synchronized)
return SynchronizedTransmitRawPayload(wr.ToByteArray());
else {
TransmitRawPayload(wr.ToByteArray());
return null;
}
}