* Copyright (c) 2015, 2018, Oracle and/or its affiliates. All rights reserved.

import java.nio.ByteBuffer;

import java.text.MessageFormat;

import java.util.LinkedList;

import java.util.List;

import java.util.Locale;

import javax.net.ssl.SSLProtocolException;

import sun.security.ssl.SSLExtension.ExtensionConsumer;

import sun.security.ssl.SSLExtension.SSLExtensionSpec;

import sun.security.ssl.SSLHandshake.HandshakeMessage;

/**

 * Pack of the "signature_algorithms" extensions [RFC 5246].

 */

final class SignatureAlgorithmsExtension {

    static final HandshakeProducer chNetworkProducer =

            new CHSignatureSchemesProducer();

    static final ExtensionConsumer chOnLoadConcumer =

            new CHSignatureSchemesConsumer();

    static final HandshakeAbsence chOnLoadAbsence =

            new CHSignatureSchemesAbsence();

    static final HandshakeConsumer chOnTradeConsumer =

            new CHSignatureSchemesUpdate();

    static final HandshakeProducer crNetworkProducer =

            new CRSignatureSchemesProducer();

    static final ExtensionConsumer crOnLoadConcumer =

            new CRSignatureSchemesConsumer();

    static final HandshakeAbsence crOnLoadAbsence =

            new CRSignatureSchemesAbsence();

    static final HandshakeConsumer crOnTradeConsumer =

            new CRSignatureSchemesUpdate();

    static final SSLStringize ssStringize =

            new SignatureSchemesStringize();

    /**

     * The "signature_algorithms" extension.

     */

    static final class SignatureSchemesSpec implements SSLExtensionSpec {

        final int[] signatureSchemes;

        SignatureSchemesSpec(List<SignatureScheme> schemes) {

            if (schemes != null) {

                signatureSchemes = new int[schemes.size()];

                int i = 0;

                for (SignatureScheme scheme : schemes) {

                    signatureSchemes[i++] = scheme.id;

                }

            } else {

                this.signatureSchemes = new int[0];

            }

        }

        SignatureSchemesSpec(ByteBuffer buffer) throws IOException {

            if (buffer.remaining() < 2) {      // 2: the length of the list

                throw new SSLProtocolException(

                    "Invalid signature_algorithms: insufficient data");

            }

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

            if (buffer.hasRemaining()) {

                throw new SSLProtocolException(

                    "Invalid signature_algorithms: unknown extra data");

            }

            if (algs == null || algs.length == 0 || (algs.length & 0x01) != 0) {

                throw new SSLProtocolException(

                    "Invalid signature_algorithms: incomplete data");

            }

            int[] schemes = new int[algs.length / 2];

            for (int i = 0, j = 0; i < algs.length;) {

                byte hash = algs[i++];

                byte sign = algs[i++];

                schemes[j++] = ((hash & 0xFF) << 8) | (sign & 0xFF);

            }

            this.signatureSchemes = schemes;

        }

        @Override

        public String toString() {

            MessageFormat messageFormat = new MessageFormat(

                "\"signature schemes\": '['{0}']'", Locale.ENGLISH);

            if (signatureSchemes == null || signatureSchemes.length == 0) {

                Object[] messageFields = {

                        "<no supported signature schemes specified>"

                    };

                return messageFormat.format(messageFields);

            } else {

                StringBuilder builder = new StringBuilder(512);

                boolean isFirst = true;

                for (int pv : signatureSchemes) {

                    if (isFirst) {

                        isFirst = false;

                    } else {

                        builder.append(", ");

                    }

                    builder.append(SignatureScheme.nameOf(pv));

                }

                Object[] messageFields = {

                        builder.toString()

                    };

                return messageFormat.format(messageFields);

            }

        }

    private static final

            class SignatureSchemesStringize implements SSLStringize {

        @Override

        public String toString(ByteBuffer buffer) {

            try {

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

            } catch (IOException ioe) {

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

                return ioe.getMessage();

            }

        }

    }

    /**

     * Network data producer of a "signature_algorithms" extension in

     * the ClientHello handshake message.

     */

    private static final

            class CHSignatureSchemesProducer implements HandshakeProducer {

        // Prevent instantiation of this class.

        private CHSignatureSchemesProducer() {

            // 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_SIGNATURE_ALGORITHMS)) {

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

                    SSLLogger.fine(

                        "Ignore unavailable signature_algorithms extension");

                }

                return null;

            }

            // Produce the extension.

            if (chc.localSupportedSignAlgs == null) {

                chc.localSupportedSignAlgs =

                    SignatureScheme.getSupportedAlgorithms(

                            chc.algorithmConstraints, chc.activeProtocols);

            }

            int vectorLen = SignatureScheme.sizeInRecord() *

                    chc.localSupportedSignAlgs.size();

            byte[] extData = new byte[vectorLen + 2];

            ByteBuffer m = ByteBuffer.wrap(extData);

            Record.putInt16(m, vectorLen);

            for (SignatureScheme ss : chc.localSupportedSignAlgs) {

                Record.putInt16(m, ss.id);

            }

            // Update the context.

            chc.handshakeExtensions.put(

                    SSLExtension.CH_SIGNATURE_ALGORITHMS,

                    new SignatureSchemesSpec(chc.localSupportedSignAlgs));

            return extData;

        }

    }

    /**

     * Network data consumer of a "signature_algorithms" extension in

     * the ClientHello handshake message.

     */

    private static final

            class CHSignatureSchemesConsumer implements ExtensionConsumer {

        // Prevent instantiation of this class.

        private CHSignatureSchemesConsumer() {

            // blank

        @Override

        public void consume(ConnectionContext context,

            HandshakeMessage message, ByteBuffer buffer) throws IOException {

            // The comsuming happens in server side only.

            ServerHandshakeContext shc = (ServerHandshakeContext)context;

            // Is it a supported and enabled extension?

            if (!shc.sslConfig.isAvailable(

                    SSLExtension.CH_SIGNATURE_ALGORITHMS)) {

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

                    SSLLogger.fine(

                        "Ignore unavailable signature_algorithms extension");

                }

                return;     // ignore the extension

            }

            // Parse the extension.

            SignatureSchemesSpec spec;

            try {

                spec = new SignatureSchemesSpec(buffer);

            } catch (IOException ioe) {

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

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

            }

            // Update the context.

            shc.handshakeExtensions.put(

                    SSLExtension.CH_SIGNATURE_ALGORITHMS, spec);

            // No impact on session resumption.

    /**

     * After session creation consuming of a "signature_algorithms"

     * extension in the ClientHello handshake message.

     */

    private static final class CHSignatureSchemesUpdate

            implements HandshakeConsumer {

        // Prevent instantiation of this class.

        private CHSignatureSchemesUpdate() {

            // blank

        }

        @Override

        public void consume(ConnectionContext context,

                HandshakeMessage message) throws IOException {

            // The comsuming happens in server side only.

            ServerHandshakeContext shc = (ServerHandshakeContext)context;

            SignatureSchemesSpec spec =

                    (SignatureSchemesSpec)shc.handshakeExtensions.get(

                            SSLExtension.CH_SIGNATURE_ALGORITHMS);

            if (spec == null) {

                // Ignore, no "signature_algorithms" extension requested.

                return;

            }

            // update the context

            List<SignatureScheme> shemes =

                    SignatureScheme.getSupportedAlgorithms(

                            shc.algorithmConstraints, shc.negotiatedProtocol,

                            spec.signatureSchemes);

            shc.peerRequestedSignatureSchemes = shemes;

            // If no "signature_algorithms_cert" extension is present, then

            // the "signature_algorithms" extension also applies to

            // signatures appearing in certificates.

            SignatureSchemesSpec certSpec =

                    (SignatureSchemesSpec)shc.handshakeExtensions.get(

                            SSLExtension.CH_SIGNATURE_ALGORITHMS_CERT);

            if (certSpec == null) {

                shc.peerRequestedCertSignSchemes = shemes;

            }

            shc.handshakeSession.setPeerSupportedSignatureAlgorithms(shemes);

            if (!shc.isResumption && shc.negotiatedProtocol.useTLS13PlusSpec()) {

                if (shc.sslConfig.clientAuthType !=

                        ClientAuthType.CLIENT_AUTH_NONE) {

                    shc.handshakeProducers.putIfAbsent(

                            SSLHandshake.CERTIFICATE_REQUEST.id,

                            SSLHandshake.CERTIFICATE_REQUEST);

                }

                shc.handshakeProducers.put(

                        SSLHandshake.CERTIFICATE.id,

                        SSLHandshake.CERTIFICATE);

                shc.handshakeProducers.putIfAbsent(

                        SSLHandshake.CERTIFICATE_VERIFY.id,

                        SSLHandshake.CERTIFICATE_VERIFY);

            }

        }

    /**

     * The absence processing if a "signature_algorithms" extension is

     * not present in the ClientHello handshake message.

     */

    private static final

            class CHSignatureSchemesAbsence implements HandshakeAbsence {

        @Override

        public void absent(ConnectionContext context,

                HandshakeMessage message) throws IOException {

            // The comsuming happens in server side only.

            ServerHandshakeContext shc = (ServerHandshakeContext)context;

            // This is a mandatory extension for certificate authentication

            // in TLS 1.3.

            //

            // We may support the server authentication other than X.509

            // certificate later.

            if (shc.negotiatedProtocol.useTLS13PlusSpec()) {

                shc.conContext.fatal(Alert.MISSING_EXTENSION,

                    "No mandatory signature_algorithms extension in the " +

                    "received CertificateRequest handshake message");

            }

    /**

     * Network data producer of a "signature_algorithms" extension in

     * the CertificateRequest handshake message.

     */

    private static final

            class CRSignatureSchemesProducer implements HandshakeProducer {

        // Prevent instantiation of this class.

        private CRSignatureSchemesProducer() {

            // blank

        @Override

        public byte[] produce(ConnectionContext context,

                HandshakeMessage message) throws IOException {

            // The producing happens in server side only.

            ServerHandshakeContext shc = (ServerHandshakeContext)context;

            // Is it a supported and enabled extension?

            //

            // Note that this is a mandatory extension for CertificateRequest

            // handshake message in TLS 1.3.

            if (!shc.sslConfig.isAvailable(

                    SSLExtension.CR_SIGNATURE_ALGORITHMS)) {

                shc.conContext.fatal(Alert.MISSING_EXTENSION,

                        "No available signature_algorithms extension " +

                        "for client certificate authentication");

                return null;    // make the compiler happy

            }

            // Produce the extension.

            if (shc.localSupportedSignAlgs == null) {

                shc.localSupportedSignAlgs =

                    SignatureScheme.getSupportedAlgorithms(

                            shc.algorithmConstraints, shc.activeProtocols);

            }

            int vectorLen = SignatureScheme.sizeInRecord() *

                    shc.localSupportedSignAlgs.size();

            byte[] extData = new byte[vectorLen + 2];

            ByteBuffer m = ByteBuffer.wrap(extData);

            Record.putInt16(m, vectorLen);

            for (SignatureScheme ss : shc.localSupportedSignAlgs) {

                Record.putInt16(m, ss.id);

            }

            // Update the context.

            shc.handshakeExtensions.put(

                    SSLExtension.CR_SIGNATURE_ALGORITHMS,

                    new SignatureSchemesSpec(shc.localSupportedSignAlgs));

            return extData;

        }

    }

    /**

     * Network data consumer of a "signature_algorithms" extension in

     * the CertificateRequest handshake message.

     */

    private static final

            class CRSignatureSchemesConsumer implements ExtensionConsumer {

        // Prevent instantiation of this class.

        private CRSignatureSchemesConsumer() {

            // blank

        }

        @Override

        public void consume(ConnectionContext context,

            HandshakeMessage message, ByteBuffer buffer) throws IOException {

            // The comsuming happens in client side only.

            ClientHandshakeContext chc = (ClientHandshakeContext)context;

            // Is it a supported and enabled extension?

            //

            // Note that this is a mandatory extension for CertificateRequest

            // handshake message in TLS 1.3.

            if (!chc.sslConfig.isAvailable(

                    SSLExtension.CR_SIGNATURE_ALGORITHMS)) {

                chc.conContext.fatal(Alert.HANDSHAKE_FAILURE,

                        "No available signature_algorithms extension " +

                        "for client certificate authentication");

                return;     // make the compiler happy

            }

            // Parse the extension.

            SignatureSchemesSpec spec;

            try {

                spec = new SignatureSchemesSpec(buffer);

            } catch (IOException ioe) {

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

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

            }

            List<SignatureScheme> knownSignatureSchemes = new LinkedList<>();

            for (int id : spec.signatureSchemes) {

                SignatureScheme ss = SignatureScheme.valueOf(id);

                if (ss != null) {

                    knownSignatureSchemes.add(ss);

                }

            }

            // Update the context.

            // chc.peerRequestedSignatureSchemes = knownSignatureSchemes;

            chc.handshakeExtensions.put(

                    SSLExtension.CR_SIGNATURE_ALGORITHMS, spec);

            // No impact on session resumption.

        }

    }

    /**

     * After session creation consuming of a "signature_algorithms"

     * extension in the CertificateRequest handshake message.

     */

    private static final class CRSignatureSchemesUpdate

            implements HandshakeConsumer {

        // Prevent instantiation of this class.

        private CRSignatureSchemesUpdate() {

            // blank

        }

        @Override

        public void consume(ConnectionContext context,

                HandshakeMessage message) throws IOException {

            // The comsuming happens in client side only.

            ClientHandshakeContext chc = (ClientHandshakeContext)context;

            SignatureSchemesSpec spec =

                    (SignatureSchemesSpec)chc.handshakeExtensions.get(

                            SSLExtension.CR_SIGNATURE_ALGORITHMS);

            if (spec == null) {

                // Ignore, no "signature_algorithms" extension requested.

                return;

            }

            // update the context

            List<SignatureScheme> shemes =

                    SignatureScheme.getSupportedAlgorithms(

                            chc.algorithmConstraints, chc.negotiatedProtocol,

                            spec.signatureSchemes);

            chc.peerRequestedSignatureSchemes = shemes;

            // If no "signature_algorithms_cert" extension is present, then

            // the "signature_algorithms" extension also applies to

            // signatures appearing in certificates.

            SignatureSchemesSpec certSpec =

                    (SignatureSchemesSpec)chc.handshakeExtensions.get(

                            SSLExtension.CH_SIGNATURE_ALGORITHMS_CERT);

            if (certSpec == null) {

                chc.peerRequestedCertSignSchemes = shemes;

            }

            chc.handshakeSession.setPeerSupportedSignatureAlgorithms(shemes);

        }

    }

    /**

     * The absence processing if a "signature_algorithms" extension is

     * not present in the CertificateRequest handshake message.

     */

    private static final

            class CRSignatureSchemesAbsence implements HandshakeAbsence {

        @Override