private void Reinitialize(Protocol protocol, ProtocolConfig config, State state)
{
bool fallback = state == State.Switch && (protocol.Modifiers & PatternModifiers.Fallback) != 0;
if (fallback && handshakeState == null)
{
throw new InvalidOperationException("Cannot perform the fallback handshake on an uninitialized server.");
}
if (protocol.HandshakePattern.Patterns.Count() == 1)
{
throw new NotSupportedException("One-way patterns are not yet supported.");
}
if (transport != null)
{
throw new InvalidOperationException($"Cannot change protocol after the handshake has been completed.");
}
if (this.state != State.Initial)
{
throw new InvalidOperationException($"Cannot change protocol more than once.");
}
this.protocol = protocol;
this.config = config;
this.state = state;
this.fallback = fallback;
if (!fallback && handshakeState != null)
{
handshakeState.Dispose();
handshakeState = null;
}
isNextMessageEncrypted = IsInitialMessageEncrypted(protocol);
}
/// <summary>
/// Releases all resources used by the current
/// instance of the <see cref="NoiseSocket"/> class.
/// </summary>
public void Dispose()
{
if (!disposed)
{
if (!leaveOpen)
{
stream.Dispose();
}
handshakeState?.Dispose();
transport?.Dispose();
disposed = true;
}
}
/// <summary>
/// Perform handshake protocol if it has not been already run.
/// </summary>
/// <remarks>
/// Most uses of this package need not call Handshake explicitly:
/// the first Read or Write will call it automatically.
/// </remarks>
internal void HandShake()
{
// Locking the handshakeMutex
this.handshakeMutex.WaitOne();
HandshakeState handshakeState = null;
try
{
Strobe c1;
Strobe c2;
byte[] receivedPayload = null;
// did we already go through the handshake?
if (this.handshakeComplite)
{
return;
}
KeyPair remoteKeyPair = null;
if (this.config.RemoteKey != null)
{
if (this.config.RemoteKey.Length != Asymmetric.DhLen)
{
throw new Exception($"disco: the provided remote key is not {Asymmetric.DhLen}-byte");
}
remoteKeyPair = new KeyPair {
PublicKey = new byte[this.config.RemoteKey.Length]
};
Array.Copy(this.config.RemoteKey, remoteKeyPair.PublicKey, this.config.RemoteKey.Length);
}
handshakeState = DiscoHelper.InitializeDisco(
this.config.HandshakePattern,
this.isClient,
this.config.Prologue,
this.config.KeyPair,
null,
remoteKeyPair,
null);
// pre-shared key
handshakeState.Psk = this.config.PreSharedKey;
do
{
// start handshake
if (handshakeState.ShouldWrite)
{
// we're writing the next message pattern
// if it's the message pattern and we're sending a static key, we also send a proof
// TODO: is this the best way of sending a proof :/ ?
byte[] bufToWrite;
if (handshakeState.MessagePatterns.Length <= 2 && this.config.StaticPublicKeyProof != null)
{
(c1, c2) = handshakeState.WriteMessage(this.config.StaticPublicKeyProof, out bufToWrite);
}
else
{
(c1, c2) = handshakeState.WriteMessage(new byte[] { }, out bufToWrite);
}
// header (length)
var length = new[] { (byte)(bufToWrite.Length >> 8), (byte)(bufToWrite.Length % 256) };
// write
var dataToWrite = length.Concat(bufToWrite).ToArray();
this.connectionStream.Write(dataToWrite, 0, dataToWrite.Length);
}
else
{
var bufHeader = this.ReadFromUntil(this.connectionStream, 2);
var length = (bufHeader[0] << 8) | bufHeader[1];
if (length > Config.NoiseMessageLength)
{
throw new Exception("disco: Disco message received exceeds DiscoMessageLength");
}
var noiseMessage = this.ReadFromUntil(this.connectionStream, length);
(c1, c2) = handshakeState.ReadMessage(noiseMessage, out receivedPayload);
}
}while (c1 == null);
// Has the other peer been authenticated so far?
if (!this.isRemoteAuthenticated && this.config.PublicKeyVerifier != null)
{
byte isRemoteStaticKeySet = 0;
// test if remote static key is empty
foreach (var val in handshakeState.Rs.PublicKey)
{
isRemoteStaticKeySet |= val;
}
if (isRemoteStaticKeySet != 0)
{
// a remote static key has been received. Verify it
if (!this.config.PublicKeyVerifier(handshakeState.Rs.PublicKey, receivedPayload))
{
throw new Exception("disco: the received public key could not be authenticated");
}
this.isRemoteAuthenticated = true;
this.RemotePublicKey = handshakeState.Rs.PublicKey;
}
}
// Processing the final handshake message returns two CipherState objects
// the first for encrypting transport messages from initiator to responder
// and the second for messages in the other direction.
if (c2 != null)
{
if (this.isClient)
{
(this.strobeOut, this.strobeIn) = (c1, c2);
}
else
{
(this.strobeOut, this.strobeIn) = (c2, c1);
}
}
else
{
this.IsHalfDuplex = true;
this.strobeIn = c1;
this.strobeOut = c1;
}
// TODO: preserve c.hs.symmetricState.h
// At that point the HandshakeState should be deleted except for the hash value h, which may be used for post-handshake channel binding (see Section 11.2).
handshakeState.Dispose();
// no errors :)
this.handshakeComplite = true;
}
finally
{
handshakeState?.Dispose();
this.handshakeMutex.ReleaseMutex();
}
}
/// <summary>
/// Disco peer initialization
/// </summary>
/// <param name="handshakeType">Noise handshake pattern</param>
/// <param name="initiator">This party initiates connection</param>
/// <param name="prologue">Prologue string, some data prior to handshake</param>
/// <param name="s">local static key</param>
/// <param name="e">local ephemeral key</param>
/// <param name="rs">remote static key</param>
/// <param name="re">remote ephemeral key</param>
/// <returns>Initialized Disco handshake state</returns>
public static HandshakeState InitializeDisco(
NoiseHandshakeType handshakeType,
bool initiator,
byte[] prologue,
KeyPair s,
KeyPair e,
KeyPair rs,
KeyPair re)
{
var handshakePattern = HandshakePattern.GetPattern(handshakeType);
var handshakeState = new HandshakeState
{
SymmetricState = new SymmetricState($"Noise_{handshakePattern.Name}_25519_STROBEv1.0.2"),
Initiator = initiator,
ShouldWrite = initiator
};
try
{
if (prologue != null)
{
handshakeState.SymmetricState.MixHash(prologue);
}
if (s != null)
{
handshakeState.S = s;
}
if (e != null)
{
throw new NotSupportedException("disco: fallback patterns are not implemented");
}
if (rs != null)
{
handshakeState.Rs = rs;
}
if (re != null)
{
throw new NotSupportedException("disco: fallback patterns are not implemented");
}
//Calls MixHash() once for each public key listed in the pre-messages from handshake_pattern,
//with the specified public key as input (see Section 7 for an explanation of pre-messages).
//If both initiator and responder have pre-messages, the initiator's public keys are hashed first.
// initiator pre-message pattern
foreach (var token in handshakePattern.PreMessagePatterns[0])
{
if (token == Tokens.TokenS)
{
if (initiator)
{
if (s == null)
{
throw new Exception("disco: the static key of the client should be set");
}
handshakeState.SymmetricState.MixHash(s.PublicKey);
}
else
{
if (rs == null)
{
throw new Exception("disco: the remote static key of the server should be set");
}
handshakeState.SymmetricState.MixHash(rs.PublicKey);
}
}
else
{
throw new Exception("disco: token of pre-message not supported");
}
}
// responder pre-message pattern
foreach (var token in handshakePattern.PreMessagePatterns[1])
{
if (token == Tokens.TokenS)
{
if (initiator)
{
if (rs == null)
{
throw new Exception("disco: the remote static key of the client should be set");
}
handshakeState.SymmetricState.MixHash(rs.PublicKey);
}
else
{
if (s == null)
{
throw new Exception("disco: the static key of the server should be set");
}
handshakeState.SymmetricState.MixHash(s.PublicKey);
}
}
else
{
throw new NotSupportedException("disco: token of pre - message not supported");
}
}
handshakeState.MessagePatterns = handshakePattern.MessagePatterns;
return(handshakeState);
}
catch (Exception)
{
handshakeState.Dispose();
throw;
}
}