/*

 * Copyright (c) 1996, 2012, Oracle and/or its affiliates. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.  Oracle designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Oracle in the LICENSE file that accompanied this code.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

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 */

package sun.security.ssl;

import java.io.*;

import java.util.*;

import java.security.*;

import java.security.cert.*;

import java.security.interfaces.*;

import java.security.spec.ECParameterSpec;

import javax.crypto.SecretKey;

import javax.crypto.spec.SecretKeySpec;

import javax.net.ssl.*;

import javax.security.auth.Subject;

import sun.security.ssl.HandshakeMessage.*;

import sun.security.ssl.CipherSuite.*;

import sun.security.ssl.SignatureAndHashAlgorithm.*;

import static sun.security.ssl.CipherSuite.*;

import static sun.security.ssl.CipherSuite.KeyExchange.*;

/**

 * ServerHandshaker does the protocol handshaking from the point

 * of view of a server.  It is driven asychronously by handshake messages

 * as delivered by the parent Handshaker class, and also uses

 * common functionality (e.g. key generation) that is provided there.

 *

 * @author David Brownell

 */

final class ServerHandshaker extends Handshaker {

    // is the server going to require the client to authenticate?

    private byte                doClientAuth;

    // our authentication info

    private X509Certificate[]   certs;

    private PrivateKey          privateKey;

    private SecretKey[]       kerberosKeys;

    // flag to check for clientCertificateVerify message

    private boolean             needClientVerify = false;

    /*

     * For exportable ciphersuites using non-exportable key sizes, we use

     * ephemeral RSA keys. We could also do anonymous RSA in the same way

     * but there are no such ciphersuites currently defined.

     */

    private PrivateKey          tempPrivateKey;

    private PublicKey           tempPublicKey;

    /*

     * For anonymous and ephemeral Diffie-Hellman key exchange, we use

     * ephemeral Diffie-Hellman keys.

     */

    private DHCrypt dh;

    // Helper for ECDH based key exchanges

    private ECDHCrypt ecdh;

    // version request by the client in its ClientHello

    // we remember it for the RSA premaster secret version check

    private ProtocolVersion clientRequestedVersion;

    private SupportedEllipticCurvesExtension supportedCurves;

    // the preferable signature algorithm used by ServerKeyExchange message

    SignatureAndHashAlgorithm preferableSignatureAlgorithm;

    /*

     * Constructor ... use the keys found in the auth context.

     */

    ServerHandshaker(SSLSocketImpl socket, SSLContextImpl context,

            ProtocolList enabledProtocols, byte clientAuth,

            ProtocolVersion activeProtocolVersion, boolean isInitialHandshake,

            boolean secureRenegotiation,

            byte[] clientVerifyData, byte[] serverVerifyData) {

        super(socket, context, enabledProtocols,

                (clientAuth != SSLEngineImpl.clauth_none), false,

                activeProtocolVersion, isInitialHandshake, secureRenegotiation,

                clientVerifyData, serverVerifyData);

        doClientAuth = clientAuth;

    }

    /*

     * Constructor ... use the keys found in the auth context.

     */

    ServerHandshaker(SSLEngineImpl engine, SSLContextImpl context,

            ProtocolList enabledProtocols, byte clientAuth,

            ProtocolVersion activeProtocolVersion,

            boolean isInitialHandshake, boolean secureRenegotiation,

            byte[] clientVerifyData, byte[] serverVerifyData) {

        super(engine, context, enabledProtocols,

                (clientAuth != SSLEngineImpl.clauth_none), false,

                activeProtocolVersion, isInitialHandshake, secureRenegotiation,

                clientVerifyData, serverVerifyData);

        doClientAuth = clientAuth;

    }

    /*

     * As long as handshaking has not started, we can change

     * whether client authentication is required.  Otherwise,

     * we will need to wait for the next handshake.

     */

    void setClientAuth(byte clientAuth) {

        doClientAuth = clientAuth;

    }

    /*

     * This routine handles all the server side handshake messages, one at

     * a time.  Given the message type (and in some cases the pending cipher

     * spec) it parses the type-specific message.  Then it calls a function

     * that handles that specific message.

     *

     * It updates the state machine as each message is processed, and writes

     * responses as needed using the connection in the constructor.

     */

    void processMessage(byte type, int message_len)

            throws IOException {

        //

        // In SSLv3 and TLS, messages follow strictly increasing

        // numerical order _except_ for one annoying special case.

        //

        if ((state > type)

                && (state != HandshakeMessage.ht_client_key_exchange

                    && type != HandshakeMessage.ht_certificate_verify)) {

            throw new SSLProtocolException(

                    "Handshake message sequence violation, state = " + state

                    + ", type = " + type);

        }

        switch (type) {

            case HandshakeMessage.ht_client_hello:

                ClientHello ch = new ClientHello(input, message_len);

                /*

                 * send it off for processing.

                 */

                this.clientHello(ch);

                break;

            case HandshakeMessage.ht_certificate:

                if (doClientAuth == SSLEngineImpl.clauth_none) {

                    fatalSE(Alerts.alert_unexpected_message,

                                "client sent unsolicited cert chain");

                    // NOTREACHED

                }

                this.clientCertificate(new CertificateMsg(input));

                break;

            case HandshakeMessage.ht_client_key_exchange:

                SecretKey preMasterSecret;

                switch (keyExchange) {

                case K_RSA:

                case K_RSA_EXPORT:

                    /*

                     * The client's pre-master secret is decrypted using

                     * either the server's normal private RSA key, or the

                     * temporary one used for non-export or signing-only

                     * certificates/keys.

                     */

                    RSAClientKeyExchange pms = new RSAClientKeyExchange(

                            protocolVersion, clientRequestedVersion,

                            sslContext.getSecureRandom(), input,

                            message_len, privateKey);

                    preMasterSecret = this.clientKeyExchange(pms);

                    break;

                case K_KRB5:

                case K_KRB5_EXPORT:

                    preMasterSecret = this.clientKeyExchange(

                        new KerberosClientKeyExchange(protocolVersion,

                            clientRequestedVersion,

                            sslContext.getSecureRandom(),

                            input,

                            kerberosKeys));

                    break;

                case K_DHE_RSA:

                case K_DHE_DSS:

                case K_DH_ANON:

                    /*

                     * The pre-master secret is derived using the normal

                     * Diffie-Hellman calculation.   Note that the main

                     * protocol difference in these five flavors is in how

                     * the ServerKeyExchange message was constructed!

                     */

                    preMasterSecret = this.clientKeyExchange(

                            new DHClientKeyExchange(input));

                    break;

                case K_ECDH_RSA:

                case K_ECDH_ECDSA:

                case K_ECDHE_RSA:

                case K_ECDHE_ECDSA:

                case K_ECDH_ANON:

                    preMasterSecret = this.clientKeyExchange

                                            (new ECDHClientKeyExchange(input));

                    break;

                default:

                    throw new SSLProtocolException

                        ("Unrecognized key exchange: " + keyExchange);

                }

                //

                // All keys are calculated from the premaster secret

                // and the exchanged nonces in the same way.

                //

                calculateKeys(preMasterSecret, clientRequestedVersion);

                break;

            case HandshakeMessage.ht_certificate_verify:

                this.clientCertificateVerify(new CertificateVerify(input,

                            localSupportedSignAlgs, protocolVersion));

                break;

            case HandshakeMessage.ht_finished:

                this.clientFinished(

                    new Finished(protocolVersion, input, cipherSuite));

                break;

            default:

                throw new SSLProtocolException(

                        "Illegal server handshake msg, " + type);

        }

        //

        // Move the state machine forward except for that annoying

        // special case.  This means that clients could send extra

        // cert verify messages; not a problem so long as all of

        // them actually check out.

        //

        if (state < type && type != HandshakeMessage.ht_certificate_verify) {

            state = type;

        }

    }

    /*

     * ClientHello presents the server with a bunch of options, to which the

     * server replies with a ServerHello listing the ones which this session

     * will use.  If needed, it also writes its Certificate plus in some cases

     * a ServerKeyExchange message.  It may also write a CertificateRequest,

     * to elicit a client certificate.

     *

     * All these messages are terminated by a ServerHelloDone message.  In

     * most cases, all this can be sent in a single Record.

     */

    private void clientHello(ClientHello mesg) throws IOException {

        if (debug != null && Debug.isOn("handshake")) {

            mesg.print(System.out);

        }

        // Does the message include security renegotiation indication?

        boolean renegotiationIndicated = false;

        // check the TLS_EMPTY_RENEGOTIATION_INFO_SCSV

        CipherSuiteList cipherSuites = mesg.getCipherSuites();

        if (cipherSuites.contains(CipherSuite.C_SCSV)) {

            renegotiationIndicated = true;

            if (isInitialHandshake) {

                secureRenegotiation = true;

            } else {

                // abort the handshake with a fatal handshake_failure alert

                if (secureRenegotiation) {

                    fatalSE(Alerts.alert_handshake_failure,

                        "The SCSV is present in a secure renegotiation");

                } else {

                    fatalSE(Alerts.alert_handshake_failure,

                        "The SCSV is present in a insecure renegotiation");

                }

            }

        }

        // check the "renegotiation_info" extension

        RenegotiationInfoExtension clientHelloRI = (RenegotiationInfoExtension)

                    mesg.extensions.get(ExtensionType.EXT_RENEGOTIATION_INFO);

        if (clientHelloRI != null) {

            renegotiationIndicated = true;

            if (isInitialHandshake) {

                // verify the length of the "renegotiated_connection" field

                if (!clientHelloRI.isEmpty()) {

                    // abort the handshake with a fatal handshake_failure alert

                    fatalSE(Alerts.alert_handshake_failure,

                        "The renegotiation_info field is not empty");

                }

                secureRenegotiation = true;

            } else {

                if (!secureRenegotiation) {

                    // unexpected RI extension for insecure renegotiation,

                    // abort the handshake with a fatal handshake_failure alert

                    fatalSE(Alerts.alert_handshake_failure,

                        "The renegotiation_info is present in a insecure " +

                        "renegotiation");

                }

                // verify the client_verify_data value

                if (!Arrays.equals(clientVerifyData,

                                clientHelloRI.getRenegotiatedConnection())) {

                    fatalSE(Alerts.alert_handshake_failure,

                        "Incorrect verify data in ClientHello " +

                        "renegotiation_info message");

                }

            }

        } else if (!isInitialHandshake && secureRenegotiation) {

           // if the connection's "secure_renegotiation" flag is set to TRUE

           // and the "renegotiation_info" extension is not present, abort

           // the handshake.

            fatalSE(Alerts.alert_handshake_failure,

                        "Inconsistent secure renegotiation indication");

        }

        // if there is no security renegotiation indication or the previous

        // handshake is insecure.

        if (!renegotiationIndicated || !secureRenegotiation) {

            if (isInitialHandshake) {

                if (!allowLegacyHelloMessages) {

                    // abort the handshake with a fatal handshake_failure alert

                    fatalSE(Alerts.alert_handshake_failure,

                        "Failed to negotiate the use of secure renegotiation");

                }

                // continue with legacy ClientHello

                if (debug != null && Debug.isOn("handshake")) {

                    System.out.println("Warning: No renegotiation " +

                        "indication in ClientHello, allow legacy ClientHello");

                }

            } else if (!allowUnsafeRenegotiation) {

                // abort the handshake

                if (activeProtocolVersion.v >= ProtocolVersion.TLS10.v) {

                    // response with a no_renegotiation warning,

                    warningSE(Alerts.alert_no_renegotiation);

                    // invalidate the handshake so that the caller can

                    // dispose this object.

                    invalidated = true;

                    // If there is still unread block in the handshake

                    // input stream, it would be truncated with the disposal

                    // and the next handshake message will become incomplete.

                    //

                    // However, according to SSL/TLS specifications, no more

                    // handshake message could immediately follow ClientHello

                    // or HelloRequest. But in case of any improper messages,

                    // we'd better check to ensure there is no remaining bytes

                    // in the handshake input stream.

                    if (input.available() > 0) {

                        fatalSE(Alerts.alert_unexpected_message,

                            "ClientHello followed by an unexpected  " +

                            "handshake message");

                    }

                    return;

                } else {

                    // For SSLv3, send the handshake_failure fatal error.

                    // Note that SSLv3 does not define a no_renegotiation

                    // alert like TLSv1. However we cannot ignore the message

                    // simply, otherwise the other side was waiting for a

                    // response that would never come.

                    fatalSE(Alerts.alert_handshake_failure,

                        "Renegotiation is not allowed");

                }

            } else {   // !isInitialHandshake && allowUnsafeRenegotiation

                // continue with unsafe renegotiation.

                if (debug != null && Debug.isOn("handshake")) {

                    System.out.println(

                            "Warning: continue with insecure renegotiation");

                }

            }

        }

        /*

         * Always make sure this entire record has been digested before we

         * start emitting output, to ensure correct digesting order.

         */

        input.digestNow();

        /*

         * FIRST, construct the ServerHello using the options and priorities

         * from the ClientHello.  Update the (pending) cipher spec as we do

         * so, and save the client's version to protect against rollback

         * attacks.

         *

         * There are a bunch of minor tasks here, and one major one: deciding

         * if the short or the full handshake sequence will be used.

         */

        ServerHello m1 = new ServerHello();

        clientRequestedVersion = mesg.protocolVersion;

        // select a proper protocol version.

        ProtocolVersion selectedVersion =

               selectProtocolVersion(clientRequestedVersion);

        if (selectedVersion == null ||

                selectedVersion.v == ProtocolVersion.SSL20Hello.v) {

            fatalSE(Alerts.alert_handshake_failure,

                "Client requested protocol " + clientRequestedVersion +

                " not enabled or not supported");

        }

        handshakeHash.protocolDetermined(selectedVersion);

        setVersion(selectedVersion);

        m1.protocolVersion = protocolVersion;

        //

        // random ... save client and server values for later use

        // in computing the master secret (from pre-master secret)

        // and thence the other crypto keys.

        //

        // NOTE:  this use of three inputs to generating _each_ set

        // of ciphers slows things down, but it does increase the

        // security since each connection in the session can hold

        // its own authenticated (and strong) keys.  One could make

        // creation of a session a rare thing...

        //

        clnt_random = mesg.clnt_random;

        svr_random = new RandomCookie(sslContext.getSecureRandom());

        m1.svr_random = svr_random;

        session = null; // forget about the current session

        //

        // Here we go down either of two paths:  (a) the fast one, where

        // the client's asked to rejoin an existing session, and the server

        // permits this; (b) the other one, where a new session is created.

        //

        if (mesg.sessionId.length() != 0) {

            // client is trying to resume a session, let's see...

            SSLSessionImpl previous = ((SSLSessionContextImpl)sslContext

                        .engineGetServerSessionContext())

                        .get(mesg.sessionId.getId());

            //

            // Check if we can use the fast path, resuming a session.  We

            // can do so iff we have a valid record for that session, and

            // the cipher suite for that session was on the list which the

            // client requested, and if we're not forgetting any needed

            // authentication on the part of the client.

            //

            if (previous != null) {

                resumingSession = previous.isRejoinable();

                if (resumingSession) {

                    ProtocolVersion oldVersion = previous.getProtocolVersion();

                    // cannot resume session with different version

                    if (oldVersion != protocolVersion) {

                        resumingSession = false;

                    }

                }

                if (resumingSession &&

                        (doClientAuth == SSLEngineImpl.clauth_required)) {

                    try {

                        previous.getPeerPrincipal();

                    } catch (SSLPeerUnverifiedException e) {

                        resumingSession = false;

                    }

                }

                // validate subject identity

                if (resumingSession) {

                    CipherSuite suite = previous.getSuite();

                    if (suite.keyExchange == K_KRB5 ||

                        suite.keyExchange == K_KRB5_EXPORT) {

                        Principal localPrincipal = previous.getLocalPrincipal();

                        Subject subject = null;

                        try {

                            subject = AccessController.doPrivileged(

                                new PrivilegedExceptionAction<Subject>() {

                                public Subject run() throws Exception {

                                    return

                                        Krb5Helper.getServerSubject(getAccSE());

                            }});

                        } catch (PrivilegedActionException e) {

                            subject = null;

                            if (debug != null && Debug.isOn("session")) {

                                System.out.println("Attempt to obtain" +

                                                " subject failed!");

                            }

                        }

                        if (subject != null) {

                            // Eliminate dependency on KerberosPrincipal

                            Set<Principal> principals =

                                subject.getPrincipals(Principal.class);

                            if (!principals.contains(localPrincipal)) {

                                resumingSession = false;