/*

 * Copyright (c) 2018, 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.IOException;

import java.math.BigInteger;

import java.nio.ByteBuffer;

import java.security.GeneralSecurityException;

import java.security.ProviderException;

import java.security.SecureRandom;

import java.text.MessageFormat;

import java.util.Locale;

import java.util.Optional;

import javax.crypto.SecretKey;

import javax.net.ssl.SSLHandshakeException;

import sun.security.ssl.PskKeyExchangeModesExtension.PskKeyExchangeModesSpec;

import sun.security.ssl.SSLHandshake.HandshakeMessage;

/**

 * Pack of the NewSessionTicket handshake message.

 */

final class NewSessionTicket {

    private static final int MAX_TICKET_LIFETIME = 604800;  // seconds, 7 days

    static final SSLConsumer handshakeConsumer =

        new NewSessionTicketConsumer();

    static final SSLProducer kickstartProducer =

        new NewSessionTicketKickstartProducer();

    static final HandshakeProducer handshakeProducer =

        new NewSessionTicketProducer();

    /**

     * The NewSessionTicketMessage handshake message.

     */

    static final class NewSessionTicketMessage extends HandshakeMessage {

        final int ticketLifetime;

        final int ticketAgeAdd;

        final byte[] ticketNonce;

        final byte[] ticket;

        final SSLExtensions extensions;

        NewSessionTicketMessage(HandshakeContext context,

                int ticketLifetime, SecureRandom generator,

                byte[] ticketNonce, byte[] ticket) {

            super(context);

            this.ticketLifetime = ticketLifetime;

            this.ticketAgeAdd = generator.nextInt();

            this.ticketNonce = ticketNonce;

            this.ticket = ticket;

            this.extensions = new SSLExtensions(this);

        }

        NewSessionTicketMessage(HandshakeContext context,

                ByteBuffer m) throws IOException {

            super(context);

            // struct {

            //     uint32 ticket_lifetime;

            //     uint32 ticket_age_add;

            //     opaque ticket_nonce<0..255>;

            //     opaque ticket<1..2^16-1>;

            //     Extension extensions<0..2^16-2>;

            // } NewSessionTicket;

            if (m.remaining() < 14) {

                context.conContext.fatal(Alert.ILLEGAL_PARAMETER,

                    "Invalid NewSessionTicket message: no sufficient data");

            }

            this.ticketLifetime = Record.getInt32(m);

            this.ticketAgeAdd = Record.getInt32(m);

            this.ticketNonce = Record.getBytes8(m);

            if (m.remaining() < 5) {

                context.conContext.fatal(Alert.ILLEGAL_PARAMETER,

                    "Invalid NewSessionTicket message: no sufficient data");

            }

            this.ticket = Record.getBytes16(m);

            if (ticket.length == 0) {

                context.conContext.fatal(Alert.ILLEGAL_PARAMETER,

                    "No ticket in the NewSessionTicket handshake message");

            }

            if (m.remaining() < 2) {

                context.conContext.fatal(Alert.ILLEGAL_PARAMETER,

                    "Invalid NewSessionTicket message: no sufficient data");

            }

            SSLExtension[] supportedExtensions =

                    context.sslConfig.getEnabledExtensions(

                            SSLHandshake.NEW_SESSION_TICKET);

            this.extensions = new SSLExtensions(this, m, supportedExtensions);

        }

        @Override

        public SSLHandshake handshakeType() {

            return SSLHandshake.NEW_SESSION_TICKET;

        }

        @Override

        public int messageLength() {

            int extLen = extensions.length();

            if (extLen == 0) {

                extLen = 2;     // empty extensions

            }

            return 8 + ticketNonce.length + 1 +

                       ticket.length + 2 + extLen;

        }

        @Override

        public void send(HandshakeOutStream hos) throws IOException {

            hos.putInt32(ticketLifetime);

            hos.putInt32(ticketAgeAdd);

            hos.putBytes8(ticketNonce);

            hos.putBytes16(ticket);

            // Is it an empty extensions?

            if (extensions.length() == 0) {

                hos.putInt16(0);

            } else {

                extensions.send(hos);

            }

        }

        @Override

        public String toString() {

            MessageFormat messageFormat = new MessageFormat(

                "\"NewSessionTicket\": '{'\n" +

                "  \"ticket_lifetime\"      : \"{0}\",\n" +

                "  \"ticket_age_add\"       : \"{1}\",\n" +

                "  \"ticket_nonce\"         : \"{2}\",\n" +

                "  \"ticket\"               : \"{3}\",\n" +

                "  \"extensions\"           : [\n" +

                "{4}\n" +

                "  ]\n" +

                "'}'",

                Locale.ENGLISH);

            Object[] messageFields = {

                ticketLifetime,

                "<omitted>",    //ticketAgeAdd should not be logged

                Utilities.toHexString(ticketNonce),

                Utilities.toHexString(ticket),

                Utilities.indent(extensions.toString(), "    ")

            };

            return messageFormat.format(messageFields);

        }

    }

    private static SecretKey derivePreSharedKey(CipherSuite.HashAlg hashAlg,

            SecretKey resumptionMasterSecret, byte[] nonce) throws IOException {

        try {

            HKDF hkdf = new HKDF(hashAlg.name);

            byte[] hkdfInfo = SSLSecretDerivation.createHkdfInfo(

                    "tls13 resumption".getBytes(), nonce, hashAlg.hashLength);

            return hkdf.expand(resumptionMasterSecret, hkdfInfo,

                    hashAlg.hashLength, "TlsPreSharedKey");

        } catch  (GeneralSecurityException gse) {

            throw (SSLHandshakeException) new SSLHandshakeException(

                    "Could not derive PSK").initCause(gse);

        }

    }

    private static final

            class NewSessionTicketKickstartProducer implements SSLProducer {

        // Prevent instantiation of this class.

        private NewSessionTicketKickstartProducer() {

            // blank

        }

        @Override

        public byte[] produce(ConnectionContext context) throws IOException {

            // The producing happens in server side only.

            ServerHandshakeContext shc = (ServerHandshakeContext)context;

            // Is this session resumable?

            if (!shc.handshakeSession.isRejoinable()) {

                return null;

            }

            // What's the requested PSK key exchange modes?

            //

            // Note that currently, the NewSessionTicket post-handshake is

            // produced and delivered only in the current handshake context

            // if required.

            PskKeyExchangeModesSpec pkemSpec =

                    (PskKeyExchangeModesSpec)shc.handshakeExtensions.get(

                            SSLExtension.PSK_KEY_EXCHANGE_MODES);

            if (pkemSpec == null || !pkemSpec.contains(

                PskKeyExchangeModesExtension.PskKeyExchangeMode.PSK_DHE_KE)) {

                // Client doesn't support PSK with (EC)DHE key establishment.

                return null;

            }

            // get a new session ID

            SSLSessionContextImpl sessionCache = (SSLSessionContextImpl)

                shc.sslContext.engineGetServerSessionContext();

            SessionId newId = new SessionId(true,

                shc.sslContext.getSecureRandom());

            Optional<SecretKey> resumptionMasterSecret =

                shc.handshakeSession.getResumptionMasterSecret();

            if (!resumptionMasterSecret.isPresent()) {

                if (SSLLogger.isOn && SSLLogger.isOn("ssl,handshake")) {

                    SSLLogger.fine(

                        "Session has no resumption secret. No ticket sent.");

                }

                return null;

            }

            // construct the PSK and handshake message

            BigInteger nonce = shc.handshakeSession.incrTicketNonceCounter();

            byte[] nonceArr = nonce.toByteArray();

            SecretKey psk = derivePreSharedKey(

                    shc.negotiatedCipherSuite.hashAlg,

                    resumptionMasterSecret.get(), nonceArr);

            int sessionTimeoutSeconds = sessionCache.getSessionTimeout();

            if (sessionTimeoutSeconds > MAX_TICKET_LIFETIME) {

                if (SSLLogger.isOn && SSLLogger.isOn("ssl,handshake")) {

                    SSLLogger.fine(

                        "Session timeout is too long. No ticket sent.");

                }

                return null;

            }

            NewSessionTicketMessage nstm = new NewSessionTicketMessage(shc,

                sessionTimeoutSeconds, shc.sslContext.getSecureRandom(),

                nonceArr, newId.getId());

            if (SSLLogger.isOn && SSLLogger.isOn("ssl,handshake")) {

                SSLLogger.fine(

                        "Produced NewSessionTicket handshake message", nstm);

            }

            // create and cache the new session

            // The new session must be a child of the existing session so

            // they will be invalidated together, etc.

            SSLSessionImpl sessionCopy = new SSLSessionImpl(shc,

                    shc.handshakeSession.getSuite(), newId,

                    shc.handshakeSession.getCreationTime());

            shc.handshakeSession.addChild(sessionCopy);

            sessionCopy.setPreSharedKey(psk);

            sessionCopy.setPskIdentity(newId.getId());

            sessionCopy.setTicketAgeAdd(nstm.ticketAgeAdd);

            sessionCache.put(sessionCopy);

            // Output the handshake message.

            nstm.write(shc.handshakeOutput);

            shc.handshakeOutput.flush();

            // The message has been delivered.

            return null;

        }

    }

    /**

     * The "NewSessionTicket" handshake message producer.

     */

    private static final class NewSessionTicketProducer

            implements HandshakeProducer {

        // Prevent instantiation of this class.

        private NewSessionTicketProducer() {

            // blank

        }

        @Override

        public byte[] produce(ConnectionContext context,

                HandshakeMessage message) throws IOException {

            // NSTM may be sent in response to handshake messages.

            // For example: key update

            throw new ProviderException(

                "NewSessionTicket handshake producer not implemented");

        }

    }

    private static final

            class NewSessionTicketConsumer implements SSLConsumer {

        // Prevent instantiation of this class.

        private NewSessionTicketConsumer() {

            // blank

        }

        @Override

        public void consume(ConnectionContext context,

                            ByteBuffer message) throws IOException {

            // Note: Although the resumption master secret depends on the

            // client's second flight, servers which do not request client

            // authentication MAY compute the remainder of the transcript

            // independently and then send a NewSessionTicket immediately

            // upon sending its Finished rather than waiting for the client

            // Finished.

            //

            // The consuming happens in client side only.  As the server

            // may send the NewSessionTicket before handshake complete, the

            // context may be a PostHandshakeContext or HandshakeContext

            // instance.

            HandshakeContext hc = (HandshakeContext)context;

            NewSessionTicketMessage nstm =

                    new NewSessionTicketMessage(hc, message);

            if (SSLLogger.isOn && SSLLogger.isOn("ssl,handshake")) {

                SSLLogger.fine(

                "Consuming NewSessionTicket message", nstm);

            }

            // discard tickets with timeout 0

            if (nstm.ticketLifetime <= 0 ||

                nstm.ticketLifetime > MAX_TICKET_LIFETIME) {

                if (SSLLogger.isOn && SSLLogger.isOn("ssl,handshake")) {

                    SSLLogger.fine(

                    "Discarding NewSessionTicket with lifetime "

                        + nstm.ticketLifetime, nstm);

                }

                return;

            }

            SSLSessionContextImpl sessionCache = (SSLSessionContextImpl)

                hc.sslContext.engineGetClientSessionContext();

            if (sessionCache.getSessionTimeout() > MAX_TICKET_LIFETIME) {

                if (SSLLogger.isOn && SSLLogger.isOn("ssl,handshake")) {

                    SSLLogger.fine(

                    "Session cache lifetime is too long. Discarding ticket.");

                }

                return;

            }

            SSLSessionImpl sessionToSave = hc.conContext.conSession;

            Optional<SecretKey> resumptionMasterSecret =

                sessionToSave.getResumptionMasterSecret();

            if (!resumptionMasterSecret.isPresent()) {

                if (SSLLogger.isOn && SSLLogger.isOn("ssl,handshake")) {

                    SSLLogger.fine(

                    "Session has no resumption master secret. Ignoring ticket.");

                }

                return;

            }

            // derive the PSK

            SecretKey psk = derivePreSharedKey(

                sessionToSave.getSuite().hashAlg, resumptionMasterSecret.get(),

                nstm.ticketNonce);

            // create and cache the new session

            // The new session must be a child of the existing session so

            // they will be invalidated together, etc.

            SessionId newId =

                new SessionId(true, hc.sslContext.getSecureRandom());

            SSLSessionImpl sessionCopy = new SSLSessionImpl(

                    hc, sessionToSave.getSuite(), newId,

                    sessionToSave.getCreationTime());

            sessionToSave.addChild(sessionCopy);

            sessionCopy.setPreSharedKey(psk);

            sessionCopy.setTicketAgeAdd(nstm.ticketAgeAdd);

            sessionCopy.setPskIdentity(nstm.ticket);

            sessionCache.put(sessionCopy);

            // clean handshake context

            hc.conContext.finishPostHandshake();

        }

    }

}