/*

 * Copyright (c) 1999, 2016, 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.net.Socket;

import java.io.*;

import java.util.*;

import java.security.*;

import java.security.cert.*;

import java.security.cert.Certificate;

import javax.net.ssl.*;

import sun.security.provider.certpath.AlgorithmChecker;

import sun.security.action.GetPropertyAction;

public abstract class SSLContextImpl extends SSLContextSpi {

    private static final Debug debug = Debug.getInstance("ssl");

    private final EphemeralKeyManager ephemeralKeyManager;

    private final SSLSessionContextImpl clientCache;

    private final SSLSessionContextImpl serverCache;

    private boolean isInitialized;

    private X509ExtendedKeyManager keyManager;

    private X509TrustManager trustManager;

    private SecureRandom secureRandom;

    // DTLS cookie exchange manager

    private volatile HelloCookieManager helloCookieManager;

    private final boolean clientEnableStapling = Debug.getBooleanProperty(

            "jdk.tls.client.enableStatusRequestExtension", true);

    private final boolean serverEnableStapling = Debug.getBooleanProperty(

            "jdk.tls.server.enableStatusRequestExtension", false);

    private volatile StatusResponseManager statusResponseManager;

    SSLContextImpl() {

        ephemeralKeyManager = new EphemeralKeyManager();

        clientCache = new SSLSessionContextImpl();

        serverCache = new SSLSessionContextImpl();

    }

    @Override

    protected void engineInit(KeyManager[] km, TrustManager[] tm,

                                SecureRandom sr) throws KeyManagementException {

        isInitialized = false;

        keyManager = chooseKeyManager(km);

        if (tm == null) {

            try {

                TrustManagerFactory tmf = TrustManagerFactory.getInstance(

                        TrustManagerFactory.getDefaultAlgorithm());

                tmf.init((KeyStore)null);

                tm = tmf.getTrustManagers();

            } catch (Exception e) {

                // eat

            }

        }

        trustManager = chooseTrustManager(tm);

        if (sr == null) {

            secureRandom = JsseJce.getSecureRandom();

        } else {

            if (SunJSSE.isFIPS() &&

                        (sr.getProvider() != SunJSSE.cryptoProvider)) {

                throw new KeyManagementException

                    ("FIPS mode: SecureRandom must be from provider "

                    + SunJSSE.cryptoProvider.getName());

            }

            secureRandom = sr;

        }

        /*

         * The initial delay of seeding the random number generator

         * could be long enough to cause the initial handshake on our

         * first connection to timeout and fail. Make sure it is

         * primed and ready by getting some initial output from it.

         */

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

            System.out.println("trigger seeding of SecureRandom");

        }

        secureRandom.nextInt();

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

            System.out.println("done seeding SecureRandom");

        }

        isInitialized = true;

    }

    private X509TrustManager chooseTrustManager(TrustManager[] tm)

            throws KeyManagementException {

        // We only use the first instance of X509TrustManager passed to us.

        for (int i = 0; tm != null && i < tm.length; i++) {

            if (tm[i] instanceof X509TrustManager) {

                if (SunJSSE.isFIPS() &&

                        !(tm[i] instanceof X509TrustManagerImpl)) {

                    throw new KeyManagementException

                        ("FIPS mode: only SunJSSE TrustManagers may be used");

                }

                if (tm[i] instanceof X509ExtendedTrustManager) {

                    return (X509TrustManager)tm[i];

                } else {

                    return new AbstractTrustManagerWrapper(

                                        (X509TrustManager)tm[i]);

                }

            }

        }

        // nothing found, return a dummy X509TrustManager.

        return DummyX509TrustManager.INSTANCE;

    }

    private X509ExtendedKeyManager chooseKeyManager(KeyManager[] kms)

            throws KeyManagementException {

        for (int i = 0; kms != null && i < kms.length; i++) {

            KeyManager km = kms[i];

            if (!(km instanceof X509KeyManager)) {

                continue;

            }

            if (SunJSSE.isFIPS()) {

                // In FIPS mode, require that one of SunJSSE's own keymanagers

                // is used. Otherwise, we cannot be sure that only keys from

                // the FIPS token are used.

                if ((km instanceof X509KeyManagerImpl)

                            || (km instanceof SunX509KeyManagerImpl)) {

                    return (X509ExtendedKeyManager)km;

                } else {

                    // throw exception, we don't want to silently use the

                    // dummy keymanager without telling the user.

                    throw new KeyManagementException

                        ("FIPS mode: only SunJSSE KeyManagers may be used");

                }

            }

            if (km instanceof X509ExtendedKeyManager) {

                return (X509ExtendedKeyManager)km;

            }

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

                System.out.println(

                    "X509KeyManager passed to " +

                    "SSLContext.init():  need an " +

                    "X509ExtendedKeyManager for SSLEngine use");

            }

            return new AbstractKeyManagerWrapper((X509KeyManager)km);

        }

        // nothing found, return a dummy X509ExtendedKeyManager

        return DummyX509KeyManager.INSTANCE;

    }

    abstract SSLEngine createSSLEngineImpl();

    abstract SSLEngine createSSLEngineImpl(String host, int port);

    @Override

    protected SSLEngine engineCreateSSLEngine() {

        if (!isInitialized) {

            throw new IllegalStateException("SSLContext is not initialized");

        }

        return createSSLEngineImpl();

    }

    @Override

    protected SSLEngine engineCreateSSLEngine(String host, int port) {

        if (!isInitialized) {

            throw new IllegalStateException("SSLContext is not initialized");

        }

        return createSSLEngineImpl(host, port);

    }

    @Override

    protected SSLSocketFactory engineGetSocketFactory() {

        if (!isInitialized) {

            throw new IllegalStateException("SSLContext is not initialized");

        }

       return new SSLSocketFactoryImpl(this);

    }

    @Override

    protected SSLServerSocketFactory engineGetServerSocketFactory() {

        if (!isInitialized) {

            throw new IllegalStateException("SSLContext is not initialized");

        }

        return new SSLServerSocketFactoryImpl(this);

    }

    @Override

    protected SSLSessionContext engineGetClientSessionContext() {

        return clientCache;

    }

    @Override

    protected SSLSessionContext engineGetServerSessionContext() {

        return serverCache;

    }

    SecureRandom getSecureRandom() {

        return secureRandom;

    }

    X509ExtendedKeyManager getX509KeyManager() {

        return keyManager;

    }

    X509TrustManager getX509TrustManager() {

        return trustManager;

    }

    EphemeralKeyManager getEphemeralKeyManager() {

        return ephemeralKeyManager;

    }

    // Used for DTLS in server mode only, see ServerHandshaker.

    HelloCookieManager getHelloCookieManager() {

        if (!isInitialized) {

            throw new IllegalStateException("SSLContext is not initialized");

        }

        if (helloCookieManager != null) {

            return helloCookieManager;

        }

        synchronized (this) {

            if (helloCookieManager == null) {

                helloCookieManager = getHelloCookieManager(secureRandom);

            }

        }

        return helloCookieManager;

    }

    HelloCookieManager getHelloCookieManager(SecureRandom secureRandom) {

        throw new UnsupportedOperationException(

                "Cookie exchange applies to DTLS only");

    }

    StatusResponseManager getStatusResponseManager() {

        if (serverEnableStapling && statusResponseManager == null) {

            synchronized (this) {

                if (statusResponseManager == null) {

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

                        System.out.println(

                                "Initializing StatusResponseManager");

                    }

                    statusResponseManager = new StatusResponseManager();

                }

            }

        }

        return statusResponseManager;

    }

    // Get supported ProtocolList.

    abstract ProtocolList getSuportedProtocolList();

    // Get default ProtocolList for server mode.

    abstract ProtocolList getServerDefaultProtocolList();

    // Get default ProtocolList for client mode.

    abstract ProtocolList getClientDefaultProtocolList();

    // Get supported CipherSuiteList.

    abstract CipherSuiteList getSupportedCipherSuiteList();

    // Get default CipherSuiteList for server mode.

    abstract CipherSuiteList getServerDefaultCipherSuiteList();

    // Get default CipherSuiteList for client mode.

    abstract CipherSuiteList getClientDefaultCipherSuiteList();

    // Get default ProtocolList.

    ProtocolList getDefaultProtocolList(boolean roleIsServer) {

        return roleIsServer ? getServerDefaultProtocolList()

                            : getClientDefaultProtocolList();

    }

    // Get default CipherSuiteList.

    CipherSuiteList getDefaultCipherSuiteList(boolean roleIsServer) {

        return roleIsServer ? getServerDefaultCipherSuiteList()

                            : getClientDefaultCipherSuiteList();

    }

    /**

     * Return whether a protocol list is the original default enabled

     * protocols.  See: SSLSocket/SSLEngine.setEnabledProtocols()

     */

    boolean isDefaultProtocolList(ProtocolList protocols) {

        return (protocols == getServerDefaultProtocolList()) ||

               (protocols == getClientDefaultProtocolList());

    }

    /**

     * Return whether a protocol list is the original default enabled

     * protocols.  See: SSLSocket/SSLEngine.setEnabledProtocols()

     */

    boolean isDefaultCipherSuiteList(CipherSuiteList cipherSuites) {

        return (cipherSuites == getServerDefaultCipherSuiteList()) ||

               (cipherSuites == getClientDefaultCipherSuiteList());

    }

    /**

     * Return whether client or server side stapling has been enabled

     * for this SSLContextImpl

     * @param isClient true if the caller is operating in a client side role,

     * false if acting as a server.

     * @return true if stapling has been enabled for the specified role, false

     * otherwise.

     */

    boolean isStaplingEnabled(boolean isClient) {

        return isClient ? clientEnableStapling : serverEnableStapling;

    }

    /*

     * Return the list of all available CipherSuites with a priority of

     * minPriority or above.

     */

    private static CipherSuiteList getApplicableCipherSuiteList(

            ProtocolList protocols, boolean onlyEnabled) {

        int minPriority = CipherSuite.SUPPORTED_SUITES_PRIORITY;

        if (onlyEnabled) {

            minPriority = CipherSuite.DEFAULT_SUITES_PRIORITY;

        }

        Collection<CipherSuite> allowedCipherSuites =

                                    CipherSuite.allowedCipherSuites();

        TreeSet<CipherSuite> suites = new TreeSet<>();

        if (!(protocols.collection().isEmpty()) &&

                protocols.min.v != ProtocolVersion.NONE.v) {

            for (CipherSuite suite : allowedCipherSuites) {

                if (!suite.allowed || suite.priority < minPriority) {

                    continue;

                }

                if (suite.isAvailable() &&

                        !protocols.min.obsoletes(suite) &&

                        protocols.max.supports(suite)) {

                    if (SSLAlgorithmConstraints.DEFAULT.permits(

                            EnumSet.of(CryptoPrimitive.KEY_AGREEMENT),

                            suite.name, null)) {

                        suites.add(suite);

                    }

                } else if (debug != null &&

                        Debug.isOn("sslctx") && Debug.isOn("verbose")) {

                    if (protocols.min.obsoletes(suite)) {

                        System.out.println(

                            "Ignoring obsoleted cipher suite: " + suite);

                    } else if (!protocols.max.supports(suite)) {

                        System.out.println(

                            "Ignoring unsupported cipher suite: " + suite);

                    } else {

                        System.out.println(

                            "Ignoring unavailable cipher suite: " + suite);

                    }

                }

            }

        }

        return new CipherSuiteList(suites);

    }

    private static String[] getAvailableProtocols(

            ProtocolVersion[] protocolCandidates) {

        List<String> availableProtocols = Collections.<String>emptyList();

        if (protocolCandidates !=  null && protocolCandidates.length != 0) {

            availableProtocols = new ArrayList<>(protocolCandidates.length);

            for (ProtocolVersion p : protocolCandidates) {

                if (ProtocolVersion.availableProtocols.contains(p)) {

                    availableProtocols.add(p.name);

                }

            }

        }

        return availableProtocols.toArray(new String[0]);

    }

    /*

     * The SSLContext implementation for SSL/(D)TLS algorithm

     *

     * SSL/TLS protocols specify the forward compatibility and version

     * roll-back attack protections, however, a number of SSL/TLS server

     * vendors did not implement these aspects properly, and some current

     * SSL/TLS servers may refuse to talk to a TLS 1.1 or later client.

     *

     * Considering above interoperability issues, SunJSSE will not set

     * TLS 1.1 and TLS 1.2 as the enabled protocols for client by default.

     *

     * For SSL/TLS servers, there is no such interoperability issues as

     * SSL/TLS clients. In SunJSSE, TLS 1.1 or later version will be the

     * enabled protocols for server by default.

     *

     * We may change the behavior when popular TLS/SSL vendors support TLS

     * forward compatibility properly.

     *

     * SSLv2Hello is no longer necessary.  This interoperability option was

     * put in place in the late 90's when SSLv3/TLS1.0 were relatively new

     * and there were a fair number of SSLv2-only servers deployed.  Because

     * of the security issues in SSLv2, it is rarely (if ever) used, as

     * deployments should now be using SSLv3 and TLSv1.

     *

     * Considering the issues of SSLv2Hello, we should not enable SSLv2Hello

     * by default. Applications still can use it by enabling SSLv2Hello with

     * the series of setEnabledProtocols APIs.

     */

    /*

     * The base abstract SSLContext implementation for the Transport Layer

     * Security (TLS) protocols.

     *

     * This abstract class encapsulates supported and the default server

     * SSL/TLS parameters.

     *

     * @see SSLContext

     */

    private abstract static class AbstractTLSContext extends SSLContextImpl {

        private static final ProtocolList supportedProtocolList;

        private static final ProtocolList serverDefaultProtocolList;

        private static final CipherSuiteList supportedCipherSuiteList;

        private static final CipherSuiteList serverDefaultCipherSuiteList;

        static {

            if (SunJSSE.isFIPS()) {

                supportedProtocolList = new ProtocolList(new String[] {

                    ProtocolVersion.TLS10.name,

                    ProtocolVersion.TLS11.name,

                    ProtocolVersion.TLS12.name

                });

                serverDefaultProtocolList = new ProtocolList(

                        getAvailableProtocols(new ProtocolVersion[] {

                    ProtocolVersion.TLS10,

                    ProtocolVersion.TLS11,

                    ProtocolVersion.TLS12

                }));

            } else {

                supportedProtocolList = new ProtocolList(new String[] {

                    ProtocolVersion.SSL20Hello.name,

                    ProtocolVersion.SSL30.name,

                    ProtocolVersion.TLS10.name,

                    ProtocolVersion.TLS11.name,

                    ProtocolVersion.TLS12.name

                });

                serverDefaultProtocolList = new ProtocolList(

                        getAvailableProtocols(new ProtocolVersion[] {

                    ProtocolVersion.SSL20Hello,

                    ProtocolVersion.SSL30,

                    ProtocolVersion.TLS10,

                    ProtocolVersion.TLS11,

                    ProtocolVersion.TLS12

                }));

            }

            supportedCipherSuiteList = getApplicableCipherSuiteList(

                    supportedProtocolList, false);          // all supported

            serverDefaultCipherSuiteList = getApplicableCipherSuiteList(

                    serverDefaultProtocolList, true);       // enabled only

        }

        @Override

        ProtocolList getSuportedProtocolList() {

            return supportedProtocolList;

        }

        @Override

        CipherSuiteList getSupportedCipherSuiteList() {

            return supportedCipherSuiteList;

        }