/*

 * Copyright (c) 2015, 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

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 */

package sun.security.ssl;

import java.io.IOException;

import java.nio.ByteBuffer;

import java.security.CryptoPrimitive;

import java.security.GeneralSecurityException;

import java.text.MessageFormat;

import java.util.Arrays;

import java.util.Collections;

import java.util.EnumSet;

import java.util.LinkedList;

import java.util.List;

import java.util.Locale;

import java.util.Map;

import javax.net.ssl.SSLProtocolException;

import sun.security.ssl.DHKeyExchange.DHECredentials;

import sun.security.ssl.DHKeyExchange.DHEPossession;

import sun.security.ssl.ECDHKeyExchange.ECDHECredentials;

import sun.security.ssl.ECDHKeyExchange.ECDHEPossession;

import sun.security.ssl.KeyShareExtension.CHKeyShareSpec;

import sun.security.ssl.SSLExtension.ExtensionConsumer;

import sun.security.ssl.SSLExtension.SSLExtensionSpec;

import sun.security.ssl.SSLHandshake.HandshakeMessage;

import sun.security.ssl.SupportedGroupsExtension.NamedGroup;

import sun.security.ssl.SupportedGroupsExtension.NamedGroupType;

import sun.security.ssl.SupportedGroupsExtension.SupportedGroups;

import sun.security.util.HexDumpEncoder;

/**

 * Pack of the "key_share" extensions.

 */

final class KeyShareExtension {

    static final HandshakeProducer chNetworkProducer =

            new CHKeyShareProducer();

    static final ExtensionConsumer chOnLoadConsumer =

            new CHKeyShareConsumer();

    static final SSLStringizer chStringizer =

            new CHKeyShareStringizer();

    static final HandshakeProducer shNetworkProducer =

            new SHKeyShareProducer();

    static final ExtensionConsumer shOnLoadConsumer =

            new SHKeyShareConsumer();

    static final HandshakeAbsence shOnLoadAbsence =

            new SHKeyShareAbsence();

    static final SSLStringizer shStringizer =

            new SHKeyShareStringizer();

    static final HandshakeProducer hrrNetworkProducer =

            new HRRKeyShareProducer();

    static final ExtensionConsumer hrrOnLoadConsumer =

            new HRRKeyShareConsumer();

    static final HandshakeProducer hrrNetworkReproducer =

            new HRRKeyShareReproducer();

    static final SSLStringizer hrrStringizer =

            new HRRKeyShareStringizer();

    /**

     * The key share entry used in "key_share" extensions.

     */

    private static final class KeyShareEntry {

        final int namedGroupId;

        final byte[] keyExchange;

        private KeyShareEntry(int namedGroupId, byte[] keyExchange) {

            this.namedGroupId = namedGroupId;

            this.keyExchange = keyExchange;

        }

        private byte[] getEncoded() {

            byte[] buffer = new byte[keyExchange.length + 4];

                                            //  2: named group id

                                            // +2: key exchange length

            ByteBuffer m = ByteBuffer.wrap(buffer);

            try {

                Record.putInt16(m, namedGroupId);

                Record.putBytes16(m, keyExchange);

            } catch (IOException ioe) {

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

                    SSLLogger.warning(

                        "Unlikely IOException", ioe);

                }

            }

            return buffer;

        }

        private int getEncodedSize() {

            return keyExchange.length + 4;  //  2: named group id

                                            // +2: key exchange length

        }

        @Override

        public String toString() {

            MessageFormat messageFormat = new MessageFormat(

                "\n'{'\n" +

                "  \"named group\": {0}\n" +

                "  \"key_exchange\": '{'\n" +

                "{1}\n" +

                "  '}'\n" +

                "'}',", Locale.ENGLISH);

            HexDumpEncoder hexEncoder = new HexDumpEncoder();

            Object[] messageFields = {

                NamedGroup.nameOf(namedGroupId),

                Utilities.indent(hexEncoder.encode(keyExchange), "    ")

            };

            return messageFormat.format(messageFields);

        }

    }

    /**

     * The "key_share" extension in a ClientHello handshake message.

     */

    static final class CHKeyShareSpec implements SSLExtensionSpec {

        final List<KeyShareEntry> clientShares;

        private CHKeyShareSpec(List<KeyShareEntry> clientShares) {

            this.clientShares = clientShares;

        }

        private CHKeyShareSpec(ByteBuffer buffer) throws IOException {

            // struct {

            //      KeyShareEntry client_shares<0..2^16-1>;

            // } KeyShareClientHello;

            if (buffer.remaining() < 2) {

                throw new SSLProtocolException(

                    "Invalid key_share extension: " +

                    "insufficient data (length=" + buffer.remaining() + ")");

            }

            int listLen = Record.getInt16(buffer);

            if (listLen != buffer.remaining()) {

                throw new SSLProtocolException(

                    "Invalid key_share extension: " +

                    "incorrect list length (length=" + listLen + ")");

            }

            List<KeyShareEntry> keyShares = new LinkedList<>();

            while (buffer.hasRemaining()) {

                int namedGroupId = Record.getInt16(buffer);

                byte[] keyExchange = Record.getBytes16(buffer);

                if (keyExchange.length == 0) {

                    throw new SSLProtocolException(

                        "Invalid key_share extension: empty key_exchange");

                }

                keyShares.add(new KeyShareEntry(namedGroupId, keyExchange));

            }

            this.clientShares = Collections.unmodifiableList(keyShares);

        }

        @Override

        public String toString() {

            MessageFormat messageFormat = new MessageFormat(

                "\"client_shares\": '['{0}\n']'", Locale.ENGLISH);

            StringBuilder builder = new StringBuilder(512);

            for (KeyShareEntry entry : clientShares) {

                builder.append(entry.toString());

            }

            Object[] messageFields = {

                Utilities.indent(builder.toString())

            };

            return messageFormat.format(messageFields);

        }

    }

    private static final class CHKeyShareStringizer implements SSLStringizer {

        @Override

        public String toString(ByteBuffer buffer) {

            try {

                return (new CHKeyShareSpec(buffer)).toString();

            } catch (IOException ioe) {

                // For debug logging only, so please swallow exceptions.

                return ioe.getMessage();

            }

        }

    }

    /**

     * Network data producer of the extension in a ClientHello

     * handshake message.

     */

    private static final

            class CHKeyShareProducer implements HandshakeProducer {

        // Prevent instantiation of this class.

        private CHKeyShareProducer() {

            // blank

        }

        @Override

        public byte[] produce(ConnectionContext context,

                HandshakeMessage message) throws IOException {

            // The producing happens in client side only.

            ClientHandshakeContext chc = (ClientHandshakeContext)context;

            // Is it a supported and enabled extension?

            if (!chc.sslConfig.isAvailable(SSLExtension.CH_KEY_SHARE)) {

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

                    SSLLogger.fine(

                        "Ignore unavailable key_share extension");

                }

                return null;

            }

            List<NamedGroup> namedGroups;

            if (chc.serverSelectedNamedGroup != null) {

                // Response to HelloRetryRequest

                namedGroups = Arrays.asList(chc.serverSelectedNamedGroup);

            } else {

                namedGroups = chc.clientRequestedNamedGroups;

                if (namedGroups == null || namedGroups.isEmpty()) {

                    // No supported groups.

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

                        SSLLogger.warning(

                            "Ignore key_share extension, no supported groups");

                    }

                    return null;

                }

            }

            List<KeyShareEntry> keyShares = new LinkedList<>();

            for (NamedGroup ng : namedGroups) {

                SSLKeyExchange ke = SSLKeyExchange.valueOf(ng);

                if (ke == null) {

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

                        SSLLogger.warning(

                            "No key exchange for named group " + ng.name);

                    }

                    continue;

                }

                SSLPossession[] poses = ke.createPossessions(chc);

                for (SSLPossession pos : poses) {

                    // update the context

                    chc.handshakePossessions.add(pos);

                    if (!(pos instanceof ECDHEPossession) &&

                            !(pos instanceof DHEPossession)) {

                        // May need more possesion types in the future.

                        continue;

                    }

                    keyShares.add(new KeyShareEntry(ng.id, pos.encode()));

                }

                // One key share entry only.  Too much key share entries makes

                // the ClientHello handshake message really big.

                if (!keyShares.isEmpty()) {

                    break;

                }

            }

            int listLen = 0;

            for (KeyShareEntry entry : keyShares) {

                listLen += entry.getEncodedSize();

            }

            byte[] extData = new byte[listLen + 2];     //  2: list length

            ByteBuffer m = ByteBuffer.wrap(extData);

            Record.putInt16(m, listLen);

            for (KeyShareEntry entry : keyShares) {

                m.put(entry.getEncoded());

            }

            // update the context

            chc.handshakeExtensions.put(SSLExtension.CH_KEY_SHARE,

                    new CHKeyShareSpec(keyShares));

            return extData;

        }

    }

    /**

     * Network data consumer of the extension in a ClientHello

     * handshake message.

     */

    private static final class CHKeyShareConsumer implements ExtensionConsumer {

        // Prevent instantiation of this class.

        private CHKeyShareConsumer() {

            // blank

        }

        @Override

        public void consume(ConnectionContext context,

            HandshakeMessage message, ByteBuffer buffer) throws IOException {

            // The consuming happens in server side only.

            ServerHandshakeContext shc = (ServerHandshakeContext)context;

            if (shc.handshakeExtensions.containsKey(SSLExtension.CH_KEY_SHARE)) {

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

                    SSLLogger.fine(

                            "The key_share extension has been loaded");

                }

                return;

            }

            // Is it a supported and enabled extension?

            if (!shc.sslConfig.isAvailable(SSLExtension.CH_KEY_SHARE)) {

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

                    SSLLogger.fine(

                            "Ignore unavailable key_share extension");

                }

                return;     // ignore the extension

            }

            // Parse the extension

            CHKeyShareSpec spec;

            try {

                spec = new CHKeyShareSpec(buffer);

            } catch (IOException ioe) {

                shc.conContext.fatal(Alert.UNEXPECTED_MESSAGE, ioe);

                return;     // fatal() always throws, make the compiler happy.

            }

            List<SSLCredentials> credentials = new LinkedList<>();

            for (KeyShareEntry entry : spec.clientShares) {

                NamedGroup ng = NamedGroup.valueOf(entry.namedGroupId);

                if (ng == null || !SupportedGroups.isActivatable(

                        shc.sslConfig.algorithmConstraints, ng)) {

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

                        SSLLogger.fine(

                                "Ignore unsupported named group: " +

                                NamedGroup.nameOf(entry.namedGroupId));

                    }

                    continue;

                }

                if (ng.type == NamedGroupType.NAMED_GROUP_ECDHE) {

                    try {

                        ECDHECredentials ecdhec =

                            ECDHECredentials.valueOf(ng, entry.keyExchange);

                        if (ecdhec != null) {

                            if (!shc.algorithmConstraints.permits(

                                    EnumSet.of(CryptoPrimitive.KEY_AGREEMENT),

                                    ecdhec.popPublicKey)) {

                                SSLLogger.warning(

                                        "ECDHE key share entry does not " +

                                        "comply to algorithm constraints");

                            } else {

                                credentials.add(ecdhec);

                            }

                        }

                    } catch (IOException | GeneralSecurityException ex) {

                        SSLLogger.warning(

                                "Cannot decode named group: " +

                                NamedGroup.nameOf(entry.namedGroupId));

                    }

                } else if (ng.type == NamedGroupType.NAMED_GROUP_FFDHE) {

                    try {

                        DHECredentials dhec =

                                DHECredentials.valueOf(ng, entry.keyExchange);

                        if (dhec != null) {

                            if (!shc.algorithmConstraints.permits(

                                    EnumSet.of(CryptoPrimitive.KEY_AGREEMENT),

                                    dhec.popPublicKey)) {

                                SSLLogger.warning(

                                        "DHE key share entry does not " +

                                        "comply to algorithm constraints");

                            } else {

                                credentials.add(dhec);

                            }

                        }

                    } catch (IOException | GeneralSecurityException ex) {

                        SSLLogger.warning(

                                "Cannot decode named group: " +

                                NamedGroup.nameOf(entry.namedGroupId));

                    }

                }

            }

            if (!credentials.isEmpty()) {

                shc.handshakeCredentials.addAll(credentials);

            } else {

                // New handshake credentials are required from the client side.

                shc.handshakeProducers.put(

                        SSLHandshake.HELLO_RETRY_REQUEST.id,

                        SSLHandshake.HELLO_RETRY_REQUEST);

            }

            // update the context

            shc.handshakeExtensions.put(SSLExtension.CH_KEY_SHARE, spec);

        }

    }

    /**

     * The key share entry used in ServerHello "key_share" extensions.

     */

    static final class SHKeyShareSpec implements SSLExtensionSpec {

        final KeyShareEntry serverShare;

        SHKeyShareSpec(KeyShareEntry serverShare) {

            this.serverShare = serverShare;

        }

        private SHKeyShareSpec(ByteBuffer buffer) throws IOException {

            // struct {

            //      KeyShareEntry server_share;

            // } KeyShareServerHello;

            if (buffer.remaining() < 5) {       // 5: minimal server_share

                throw new SSLProtocolException(

                    "Invalid key_share extension: " +

                    "insufficient data (length=" + buffer.remaining() + ")");

            }

            int namedGroupId = Record.getInt16(buffer);

            byte[] keyExchange = Record.getBytes16(buffer);

            if (buffer.hasRemaining()) {

                throw new SSLProtocolException(

                    "Invalid key_share extension: unknown extra data");

            }

            this.serverShare = new KeyShareEntry(namedGroupId, keyExchange);

        }

        @Override

        public String toString() {

            MessageFormat messageFormat = new MessageFormat(

                "\"server_share\": '{'\n" +

                "  \"named group\": {0}\n" +

                "  \"key_exchange\": '{'\n" +

                "{1}\n" +

                "  '}'\n" +

                "'}',", Locale.ENGLISH);

            HexDumpEncoder hexEncoder = new HexDumpEncoder();

            Object[] messageFields = {

                NamedGroup.nameOf(serverShare.namedGroupId),

                Utilities.indent(

                        hexEncoder.encode(serverShare.keyExchange), "    ")

            };

            return messageFormat.format(messageFields);

        }

    }

    private static final class SHKeyShareStringizer implements SSLStringizer {

        @Override

        public String toString(ByteBuffer buffer) {

            try {

                return (new SHKeyShareSpec(buffer)).toString();

            } catch (IOException ioe) {

                // For debug logging only, so please swallow exceptions.

                return ioe.getMessage();

            }

        }

    }

    /**

     * Network data producer of the extension in a ServerHello

     * handshake message.

     */

    private static final class SHKeyShareProducer implements HandshakeProducer {

        // Prevent instantiation of this class.

        private SHKeyShareProducer() {

            // blank

        }

        @Override

        public byte[] produce(ConnectionContext context,

                HandshakeMessage message) throws IOException {

            // The producing happens in client side only.

            ServerHandshakeContext shc = (ServerHandshakeContext)context;

            // In response to key_share request only

            CHKeyShareSpec kss =

                    (CHKeyShareSpec)shc.handshakeExtensions.get(

                            SSLExtension.CH_KEY_SHARE);

            if (kss == null) {

                // Unlikely, no key_share extension requested.

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

                    SSLLogger.warning(

                            "Ignore, no client key_share extension");

                }

                return null;

            }

            // Is it a supported and enabled extension?

            if (!shc.sslConfig.isAvailable(SSLExtension.SH_KEY_SHARE)) {

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

                    SSLLogger.warning(

                            "Ignore, no available server key_share extension");

                }

                return null;

            }

            // use requested key share entries

            if ((shc.handshakeCredentials == null) ||

                    shc.handshakeCredentials.isEmpty()) {

                // Unlikely, HelloRetryRequest should be used ealier.

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

                    SSLLogger.warning(

                            "No available client key share entries");

                }

                return null;

            }

            KeyShareEntry keyShare = null;

            for (SSLCredentials cd : shc.handshakeCredentials) {