internal static ECDSAPublicKey ReadFrom(SSH2DataReader reader) {
string curveName = reader.ReadString();
byte[] q = reader.ReadByteString();
EllipticCurve curve = EllipticCurve.FindByName(curveName);
if (curve == null) {
throw new SSHException(Strings.GetString("UnsupportedEllipticCurve") + " : " + curveName);
}
ECPoint p;
if (!ECPoint.Parse(q, curve, out p)) {
throw new SSHException(Strings.GetString("InvalidECPublicKey"));
}
return new ECDSAPublicKey(curve, p);
}
private void SendSign(SSH2DataReader r)
{
byte[] blob = r.ReadByteString();
byte[] data = r.ReadByteString();
//Debug.WriteLine(String.Format("SignRequest blobsize={0} datasize={1}", blob.Length, data.Length));
SSH2UserAuthKey[] keys = _client.GetAvailableSSH2UserAuthKeys();
SSH2UserAuthKey key = FindKey(keys, blob);
if (key == null) {
TransmitWriter(OpenWriter(AgentForwadPacketType.SSH_AGENT_FAILURE));
_client.NotifyPublicKeyDidNotMatch();
}
else {
SSH2DataWriter signpack = new SSH2DataWriter();
signpack.WriteString(SSH2Util.PublicKeyAlgorithmName(key.Algorithm));
signpack.WriteAsString(key.Sign(data));
SSH2DataWriter wr = OpenWriter(AgentForwadPacketType.SSH2_AGENT_SIGN_RESPONSE);
wr.WriteAsString(signpack.ToByteArray());
TransmitWriter(wr);
}
}
internal static EDDSAPublicKey ReadFrom(PublicKeyAlgorithm algorithm, SSH2DataReader reader)
{
EdwardsCurve curve = EdwardsCurve.FindByAlgorithm(algorithm);
if (curve == null) {
throw new SSHException(Strings.GetString("UnsupportedEllipticCurve"));
}
byte[] q = reader.ReadByteString();
return new EDDSAPublicKey(curve, q);
}
private bool ProcessPacket(DataFragment packet)
{
SSH2DataReader r = new SSH2DataReader(packet);
SSH2PacketType pt = (SSH2PacketType) r.ReadByte();
if (pt == SSH2PacketType.SSH_MSG_DISCONNECT) {
int errorcode = r.ReadInt32();
_eventReceiver.OnConnectionClosed();
return false;
}
else if (_waitingForPortForwardingResponse) {
if (pt != SSH2PacketType.SSH_MSG_REQUEST_SUCCESS)
_eventReceiver.OnUnknownMessage((byte)pt, packet.GetBytes());
_waitingForPortForwardingResponse = false;
return true;
}
else if (pt == SSH2PacketType.SSH_MSG_CHANNEL_OPEN) {
string method = 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.WriteByte((byte)SSH2PacketType.SSH_MSG_CHANNEL_OPEN_FAILURE);
wr.WriteInt32(r.ReadInt32());
wr.WriteInt32(0);
wr.WriteString("unknown method");
wr.WriteString(""); //lang tag
TraceReceptionEvent("SSH_MSG_CHANNEL_OPEN rejected", "method={0}", method);
}
return true;
}
else if (pt >= SSH2PacketType.SSH_MSG_CHANNEL_OPEN_CONFIRMATION && pt <= SSH2PacketType.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, r);
else
Debug.WriteLine("unexpected channel pt=" + pt + " local_channel=" + local_channel.ToString());
return true;
}
else if (pt == SSH2PacketType.SSH_MSG_IGNORE) {
_eventReceiver.OnIgnoreMessage(r.ReadByteString());
return true;
}
else if (_asyncKeyExchanger != null) {
_asyncKeyExchanger.AsyncProcessPacket(packet);
return true;
}
else if (pt == SSH2PacketType.SSH_MSG_KEXINIT) {
//Debug.WriteLine("Host sent KEXINIT");
_asyncKeyExchanger = new KeyExchanger(this, _sessionID);
_asyncKeyExchanger.AsyncProcessPacket(packet);
return true;
}
else {
_eventReceiver.OnUnknownMessage((byte)pt, packet.GetBytes());
return false;
}
}
//synchronous reception
internal DataFragment ReceivePacket()
{
while (true) {
DataFragment data = _packetReceiver.WaitResponse();
SSH2PacketType pt = (SSH2PacketType)data[0]; //sneak
//filter unnecessary packet
if (pt == SSH2PacketType.SSH_MSG_IGNORE) {
SSH2DataReader r = new SSH2DataReader(data);
r.ReadByte(); //skip
byte[] msg = r.ReadByteString();
if (_eventReceiver != null)
_eventReceiver.OnIgnoreMessage(msg);
TraceReceptionEvent(pt, msg);
}
else if (pt == SSH2PacketType.SSH_MSG_DEBUG) {
SSH2DataReader r = new SSH2DataReader(data);
r.ReadByte(); //skip
bool f = r.ReadBool();
byte[] msg = r.ReadByteString();
if (_eventReceiver != null)
_eventReceiver.OnDebugMessage(f, msg);
TraceReceptionEvent(pt, msg);
}
else {
return data;
}
}
}
private void ProcessChannelLocalData(ISSHChannelEventReceiver receiver, SSH2PacketType pt, SSH2DataReader re)
{
switch (pt) {
case SSH2PacketType.SSH_MSG_CHANNEL_DATA: {
int len = re.ReadInt32();
DataFragment frag = re.GetRemainingDataView(len);
receiver.OnData(frag.Data, frag.Offset, frag.Length);
}
break;
case SSH2PacketType.SSH_MSG_CHANNEL_EXTENDED_DATA: {
int t = re.ReadInt32();
byte[] data = re.ReadByteString();
receiver.OnExtendedData(t, data);
}
break;
case SSH2PacketType.SSH_MSG_CHANNEL_REQUEST: {
string request = 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
Transmit(
0,
new SSH2Packet(SSH2PacketType.SSH_MSG_CHANNEL_FAILURE)
.WriteInt32(_remoteID)
);
}
}
break;
case SSH2PacketType.SSH_MSG_CHANNEL_EOF:
receiver.OnChannelEOF();
break;
case SSH2PacketType.SSH_MSG_CHANNEL_CLOSE:
_connection.ChannelCollection.UnregisterChannelEventReceiver(_localID);
receiver.OnChannelClosed();
break;
case SSH2PacketType.SSH_MSG_CHANNEL_FAILURE: {
DataFragment frag = re.GetRemainingDataView();
receiver.OnMiscPacket((byte)pt, frag.Data, frag.Offset, frag.Length);
}
break;
default: {
DataFragment frag = re.GetRemainingDataView();
receiver.OnMiscPacket((byte)pt, frag.Data, frag.Offset, frag.Length);
}
Debug.WriteLine("Unknown Packet " + pt);
break;
}
}
private bool VerifyHostKey(byte[] K_S, byte[] signature, byte[] hash)
{
SSH2DataReader re1 = new SSH2DataReader(K_S);
string algorithm = re1.ReadString();
if (algorithm != SSH2Util.PublicKeyAlgorithmName(_cInfo.HostKeyAlgorithm.Value))
throw new SSHException("Protocol Error: Host Key Algorithm Mismatch");
SSH2DataReader re2 = new SSH2DataReader(signature);
algorithm = re2.ReadString();
if (algorithm != SSH2Util.PublicKeyAlgorithmName(_cInfo.HostKeyAlgorithm.Value))
throw new SSHException("Protocol Error: Host Key Algorithm Mismatch");
byte[] sigbody = re2.ReadByteString();
Debug.Assert(re2.RemainingDataLength == 0);
if (_cInfo.HostKeyAlgorithm == PublicKeyAlgorithm.RSA) {
RSAPublicKey pk = ReadRSAPublicKey(re1, sigbody, hash);
pk.VerifyWithSHA1(sigbody, new SHA1CryptoServiceProvider().ComputeHash(hash));
_cInfo.HostKey = pk;
}
else if (_cInfo.HostKeyAlgorithm == PublicKeyAlgorithm.DSA) {
DSAPublicKey pk = ReadDSAPublicKey(re1, sigbody, hash);
pk.Verify(sigbody, new SHA1CryptoServiceProvider().ComputeHash(hash));
_cInfo.HostKey = pk;
}
else
throw new SSHException("Bad host key algorithm " + _cInfo.HostKeyAlgorithm);
//ask the client whether he accepts the host key
if (!_startedByHost && _param.VerifySSHHostKey != null) {
if (!_param.VerifySSHHostKey(_cInfo.GetSSHHostKeyInformationProvider())) {
return false;
}
}
return true;
}
private bool ProcessKEXDHREPLY(DataFragment packet)
{
//Round2 receives response
SSH2DataReader re = null;
SSH2PacketType h;
do {
re = new SSH2DataReader(packet);
h = (SSH2PacketType) re.ReadByte();
if (h == SSH2PacketType.SSH_MSG_KEXDH_REPLY)
break; //successfully exit
else if (h == SSH2PacketType.SSH_MSG_IGNORE || h == SSH2PacketType.SSH_MSG_DEBUG) { //continue
packet = _connection.ReceivePacket();
}
else
throw new SSHException(String.Format("KeyExchange response is not KEXDH_REPLY but {0}", h));
} while (true);
byte[] key_and_cert = re.ReadByteString();
BigInteger f = re.ReadMPInt();
byte[] signature = re.ReadByteString();
Debug.Assert(re.RemainingDataLength == 0);
//Round3 calc hash H
SSH2DataWriter wr = new SSH2DataWriter();
_k = f.ModPow(_x, GetDiffieHellmanPrime(_cInfo.KEXAlgorithm.Value));
wr = new SSH2DataWriter();
wr.WriteString(_cInfo.ClientVersionString);
wr.WriteString(_cInfo.ServerVersionString);
wr.WriteAsString(_clientKEXINITPayload);
wr.WriteAsString(_serverKEXINITPayload);
wr.WriteAsString(key_and_cert);
wr.WriteBigInteger(_e);
wr.WriteBigInteger(f);
wr.WriteBigInteger(_k);
_hash = KexComputeHash(wr.ToByteArray());
_connection.TraceReceptionEvent(h, "verifying host key");
if (!VerifyHostKey(key_and_cert, signature, _hash))
return false;
//Debug.WriteLine("hash="+DebugUtil.DumpByteArray(hash));
if (_sessionID == null)
_sessionID = _hash;
return true;
}
