@Override
public boolean next(Message msg, SSHPacket packet)
throws GeneralSecurityException, TransportException {
if (msg != Message.KEXDH_31)
throw new TransportException(
DisconnectReason.KEY_EXCHANGE_FAILED, "Unexpected packet: " + msg);
log.debug("Received SSH_MSG_KEXDH_REPLY");
final byte[] K_S;
final BigInteger f;
final byte[] sig; // signature sent by server
try {
K_S = packet.readBytes();
f = packet.readMPInt();
sig = packet.readBytes();
hostKey = new Buffer.PlainBuffer(K_S).readPublicKey();
} catch (Buffer.BufferException be) {
throw new TransportException(be);
}
dh.computeK(f);
final Buffer.PlainBuffer buf =
new Buffer.PlainBuffer()
.putString(V_C)
.putString(V_S)
.putString(I_C)
.putString(I_S)
.putString(K_S)
.putMPInt(dh.getE())
.putMPInt(f)
.putMPInt(dh.getK());
sha1.update(buf.array(), buf.rpos(), buf.available());
H = sha1.digest();
Signature signature =
Factory.Named.Util.create(
trans.getConfig().getSignatureFactories(), KeyType.fromKey(hostKey).toString());
signature.init(hostKey, null);
signature.update(H, 0, H.length);
if (!signature.verify(sig))
throw new TransportException(
DisconnectReason.KEY_EXCHANGE_FAILED, "KeyExchange signature verification failed");
return true;
}
@Override
public void init(Transport trans, String V_S, String V_C, byte[] I_S, byte[] I_C)
throws GeneralSecurityException, TransportException {
this.trans = trans;
this.V_S = V_S;
this.V_C = V_C;
this.I_S = Arrays.copyOf(I_S, I_S.length);
this.I_C = Arrays.copyOf(I_C, I_C.length);
sha1.init();
initDH(dh);
log.debug("Sending SSH_MSG_KEXDH_INIT");
trans.write(new SSHPacket(Message.KEXDH_INIT).putMPInt(dh.getE()));
}