/*

 * Copyright (c) 1996, 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.math.BigInteger;

import java.net.InetAddress;

import java.security.Principal;

import java.security.PrivateKey;

import java.security.cert.CertificateEncodingException;

import java.security.cert.X509Certificate;

import java.util.ArrayList;

import java.util.Queue;

import java.util.Collection;

import java.util.Collections;

import java.util.Enumeration;

import java.util.List;

import java.util.Optional;

import java.util.concurrent.ConcurrentHashMap;

import java.util.concurrent.ConcurrentLinkedQueue;

import javax.crypto.SecretKey;

import javax.net.ssl.ExtendedSSLSession;

import javax.net.ssl.SNIServerName;

import javax.net.ssl.SSLPeerUnverifiedException;

import javax.net.ssl.SSLPermission;

import javax.net.ssl.SSLSessionBindingEvent;

import javax.net.ssl.SSLSessionBindingListener;

import javax.net.ssl.SSLSessionContext;

/**

 * Implements the SSL session interface, and exposes the session context

 * which is maintained by SSL servers.

 *

 * <P> Servers have the ability to manage the sessions associated with

 * their authentication context(s).  They can do this by enumerating the

 * IDs of the sessions which are cached, examining those sessions, and then

 * perhaps invalidating a given session so that it can't be used again.

 * If servers do not explicitly manage the cache, sessions will linger

 * until memory is low enough that the runtime environment purges cache

 * entries automatically to reclaim space.

 *

 * <P><em> The only reason this class is not package-private is that

 * there's no other public way to get at the server session context which

 * is associated with any given authentication context. </em>

 *

 * @author David Brownell

 */

final class SSLSessionImpl extends ExtendedSSLSession {

    /*

     * we only really need a single null session

     */

    static final SSLSessionImpl         nullSession = new SSLSessionImpl();

    /*

     * The state of a single session, as described in section 7.1

     * of the SSLv3 spec.

     */

    private final ProtocolVersion       protocolVersion;

    private final SessionId             sessionId;

    private X509Certificate[]   peerCerts;

    private CipherSuite         cipherSuite;

    private SecretKey           masterSecret;

    final boolean               useExtendedMasterSecret;

    /*

     * Information not part of the SSLv3 protocol spec, but used

     * to support session management policies.

     */

    private final long          creationTime;

    private long                lastUsedTime = 0;

    private final String        host;

    private final int           port;

    private SSLSessionContextImpl       context;

    private boolean             invalidated;

    private X509Certificate[]   localCerts;

    private PrivateKey          localPrivateKey;

    private final Collection<SignatureScheme>     localSupportedSignAlgs;

    private String[]            peerSupportedSignAlgs;      // for certificate

    private boolean             useDefaultPeerSignAlgs = false;

    private List<byte[]>        statusResponses;

    private SecretKey           resumptionMasterSecret;

    private SecretKey           preSharedKey;

    private byte[]              pskIdentity;

    private final long          ticketCreationTime = System.currentTimeMillis();

    private int                 ticketAgeAdd;

    private int                 negotiatedMaxFragLen = -1;

    private int                 maximumPacketSize;

    private final Queue<SSLSessionImpl> childSessions =

                                        new ConcurrentLinkedQueue<>();

    /*

     * Is the session currently re-established with a session-resumption

     * abbreviated initial handshake?

     *

     * Note that currently we only set this variable in client side.

     */

    private boolean isSessionResumption = false;

    /*

     * Use of session caches is globally enabled/disabled.

     */

    private static boolean      defaultRejoinable = true;

    // server name indication

    final SNIServerName         serverNameIndication;

    private final List<SNIServerName>    requestedServerNames;

    // Counter used to create unique nonces in NewSessionTicket

    private BigInteger ticketNonceCounter = BigInteger.ONE;

    /*

     * Create a new non-rejoinable session, using the default (null)

     * cipher spec.  This constructor returns a session which could

     * be used either by a client or by a server, as a connection is

     * first opened and before handshaking begins.

     */

    private SSLSessionImpl() {

        this.protocolVersion = ProtocolVersion.NONE;

        this.cipherSuite = CipherSuite.C_NULL;

        this.sessionId = new SessionId(false, null);

        this.host = null;

        this.port = -1;

        this.localSupportedSignAlgs = Collections.emptySet();

        this.serverNameIndication = null;

        this.requestedServerNames = Collections.<SNIServerName>emptyList();

        this.useExtendedMasterSecret = false;

        this.creationTime = System.currentTimeMillis();

    }

    /*

     * Create a new session, using a given cipher spec.  This will

     * be rejoinable if session caching is enabled; the constructor

     * is intended mostly for use by serves.

     */

    SSLSessionImpl(HandshakeContext hc, CipherSuite cipherSuite) {

        this(hc, cipherSuite,

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

    }

    /*

     * Record a new session, using a given cipher spec and session ID.

     */

    SSLSessionImpl(HandshakeContext hc, CipherSuite cipherSuite, SessionId id) {

        this(hc, cipherSuite, id, System.currentTimeMillis());

    }

    /*

     * Record a new session, using a given cipher spec, session ID,

     * and creation time

     */

    SSLSessionImpl(HandshakeContext hc,

            CipherSuite cipherSuite, SessionId id, long creationTime) {

        this.protocolVersion = hc.negotiatedProtocol;

        this.cipherSuite = cipherSuite;

        this.sessionId = id;

        this.host = hc.conContext.transport.getPeerHost();

        this.port = hc.conContext.transport.getPeerPort();

        this.localSupportedSignAlgs = hc.localSupportedSignAlgs == null ?

                Collections.emptySet() :

                Collections.unmodifiableCollection(hc.localSupportedSignAlgs);

        this.serverNameIndication = hc.negotiatedServerName;

        this.requestedServerNames = Collections.<SNIServerName>unmodifiableList(

                hc.getRequestedServerNames());

        if (hc.sslConfig.isClientMode) {

            this.useExtendedMasterSecret =

                (hc.handshakeExtensions.get(

                        SSLExtension.CH_EXTENDED_MASTER_SECRET) != null) &&

                (hc.handshakeExtensions.get(

                        SSLExtension.SH_EXTENDED_MASTER_SECRET) != null);

        } else {

            this.useExtendedMasterSecret =

                (hc.handshakeExtensions.get(

                        SSLExtension.CH_EXTENDED_MASTER_SECRET) != null) &&

                (!hc.negotiatedProtocol.useTLS13PlusSpec());

        }

        this.creationTime = creationTime;

        if (SSLLogger.isOn && SSLLogger.isOn("session")) {

             SSLLogger.finest("Session initialized:  " + this);

        }

    }

    void setMasterSecret(SecretKey secret) {

        masterSecret = secret;

    }

    void setResumptionMasterSecret(SecretKey secret) {

        resumptionMasterSecret = secret;

    }

    void setPreSharedKey(SecretKey key) {

        preSharedKey = key;

    }

    void addChild(SSLSessionImpl session) {

        childSessions.add(session);

    }

    void setTicketAgeAdd(int ticketAgeAdd) {

        this.ticketAgeAdd = ticketAgeAdd;

    }

    void setPskIdentity(byte[] pskIdentity) {

        this.pskIdentity = pskIdentity;

    }

    BigInteger incrTicketNonceCounter() {

        BigInteger result = ticketNonceCounter;

        ticketNonceCounter = ticketNonceCounter.add(BigInteger.valueOf(1));

        return result;

    }

    /**

     * Returns the master secret ... treat with extreme caution!

     */

    SecretKey getMasterSecret() {

        return masterSecret;

    }

    Optional<SecretKey> getResumptionMasterSecret() {

        return Optional.ofNullable(resumptionMasterSecret);

    }

    synchronized Optional<SecretKey> getPreSharedKey() {

        return Optional.ofNullable(preSharedKey);

    }

    synchronized Optional<SecretKey> consumePreSharedKey() {

        Optional<SecretKey> result = Optional.ofNullable(preSharedKey);

        preSharedKey = null;

        return result;

    }

    int getTicketAgeAdd() {

        return ticketAgeAdd;

    }

    /*

     * Get the PSK identity. Take care not to use it in multiple connections.

     */

    synchronized Optional<byte[]> getPskIdentity() {

        return Optional.ofNullable(pskIdentity);

    }

    /* PSK identities created from new_session_ticket messages should only

     * be used once. This method will return the identity and then clear it

     * so it cannot be used again.

     */

    synchronized Optional<byte[]> consumePskIdentity() {

        Optional<byte[]> result = Optional.ofNullable(pskIdentity);

        pskIdentity = null;

        return result;

    }

    void setPeerCertificates(X509Certificate[] peer) {

        if (peerCerts == null) {

            peerCerts = peer;

        }

    }

    void setLocalCertificates(X509Certificate[] local) {

        localCerts = local;

    }

    void setLocalPrivateKey(PrivateKey privateKey) {

        localPrivateKey = privateKey;

    }

    void setPeerSupportedSignatureAlgorithms(

            Collection<SignatureScheme> signatureSchemes) {

        peerSupportedSignAlgs =

            SignatureScheme.getAlgorithmNames(signatureSchemes);

    }

    // TLS 1.2 only

    //

    // Per RFC 5246, If the client supports only the default hash

    // and signature algorithms, it MAY omit the

    // signature_algorithms extension.  If the client does not

    // support the default algorithms, or supports other hash

    // and signature algorithms (and it is willing to use them

    // for verifying messages sent by the server, i.e., server

    // certificates and server key exchange), it MUST send the

    // signature_algorithms extension, listing the algorithms it

    // is willing to accept.

    void setUseDefaultPeerSignAlgs() {

        useDefaultPeerSignAlgs = true;

        peerSupportedSignAlgs = new String[] {

            "SHA1withRSA", "SHA1withDSA", "SHA1withECDSA"};

    }

    // Returns the connection session.

    SSLSessionImpl finish() {

        if (useDefaultPeerSignAlgs) {

            this.peerSupportedSignAlgs = new String[0];

        }

        return this;

    }

    /**

     * Provide status response data obtained during the SSL handshake.

     *

     * @param responses a {@link List} of responses in binary form.

     */

    void setStatusResponses(List<byte[]> responses) {

        if (responses != null && !responses.isEmpty()) {

            statusResponses = responses;

        } else {

            statusResponses = Collections.emptyList();

        }

    }

    /**

     * Returns true iff this session may be resumed ... sessions are

     * usually resumable.  Security policies may suggest otherwise,

     * for example sessions that haven't been used for a while (say,

     * a working day) won't be resumable, and sessions might have a

     * maximum lifetime in any case.

     */

    boolean isRejoinable() {

        return sessionId != null && sessionId.length() != 0 &&

            !invalidated && isLocalAuthenticationValid();

    }

    @Override

    public synchronized boolean isValid() {

        return isRejoinable();

    }

    /**

     * Check if the authentication used when establishing this session

     * is still valid. Returns true if no authentication was used

     */

    private boolean isLocalAuthenticationValid() {

        if (localPrivateKey != null) {

            try {

                // if the private key is no longer valid, getAlgorithm()

                // should throw an exception

                // (e.g. Smartcard has been removed from the reader)

                localPrivateKey.getAlgorithm();

            } catch (Exception e) {

                invalidate();

                return false;

            }

        }

        return true;

    }

    /**

     * Returns the ID for this session.  The ID is fixed for the

     * duration of the session; neither it, nor its value, changes.

     */

    @Override

    public byte[] getId() {

        return sessionId.getId();

    }

    /**

     * For server sessions, this returns the set of sessions which

     * are currently valid in this process.  For client sessions,

     * this returns null.

     */

    @Override

    public SSLSessionContext getSessionContext() {

        /*

         * An interim security policy until we can do something

         * more specific in 1.2. Only allow trusted code (code which

         * can set system properties) to get an

         * SSLSessionContext. This is to limit the ability of code to

         * look up specific sessions or enumerate over them. Otherwise,

         * code can only get session objects from successful SSL

         * connections which implies that they must have had permission

         * to make the network connection in the first place.

         */

        SecurityManager sm;

        if ((sm = System.getSecurityManager()) != null) {

            sm.checkPermission(new SSLPermission("getSSLSessionContext"));

        }

        return context;

    }

    SessionId getSessionId() {

        return sessionId;

    }

    /**

     * Returns the cipher spec in use on this session

     */

    CipherSuite getSuite() {

        return cipherSuite;

    }

    /**

     * Resets the cipher spec in use on this session

     */

    void setSuite(CipherSuite suite) {

       cipherSuite = suite;

        if (SSLLogger.isOn && SSLLogger.isOn("session")) {

             SSLLogger.finest("Negotiating session:  " + this);

       }

    }

    /**

     * Return true if the session is currently re-established with a

     * session-resumption abbreviated initial handshake.

     */

    boolean isSessionResumption() {

        return isSessionResumption;

    }

    /**

     * Resets whether the session is re-established with a session-resumption

     * abbreviated initial handshake.

     */

    void setAsSessionResumption(boolean flag) {

        isSessionResumption = flag;

    }

    /**

     * Returns the name of the cipher suite in use on this session

     */

    @Override

    public String getCipherSuite() {

        return getSuite().name;

    }

    ProtocolVersion getProtocolVersion() {

        return protocolVersion;

    }

    /**

     * Returns the standard name of the protocol in use on this session

     */

    @Override

    public String getProtocol() {

        return getProtocolVersion().name;

    }

    /**

     * Returns the hashcode for this session

     */

    @Override

    public int hashCode() {

        return sessionId.hashCode();

    }

    /**

     * Returns true if sessions have same ids, false otherwise.

     */

    @Override

    public boolean equals(Object obj) {

        if (obj == this) {

            return true;

        }

        if (obj instanceof SSLSessionImpl) {

            SSLSessionImpl sess = (SSLSessionImpl) obj;

            return (sessionId != null) && (sessionId.equals(

                        sess.getSessionId()));

        }

        return false;

    }