/*

 * 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.net.Socket;

import java.security.*;

import java.security.cert.*;

import javax.net.ssl.*;

import sun.security.util.AnchorCertificates;

import sun.security.util.HostnameChecker;

/**

 * This class implements the SunJSSE X.509 trust manager using the internal

 * validator API in J2SE core. The logic in this class is minimal.<p>

 * <p>

 * This class supports both the Simple validation algorithm from previous

 * JSSE versions and PKIX validation. Currently, it is not possible for the

 * application to specify PKIX parameters other than trust anchors. This will

 * be fixed in a future release using new APIs. When that happens, it may also

 * make sense to separate the Simple and PKIX trust managers into separate

 * classes.

 *

 * @author Andreas Sterbenz

 */

final class X509TrustManagerImpl extends X509ExtendedTrustManager

        implements X509TrustManager {

    private final String validatorType;

    /**

     * The Set of trusted X509Certificates.

     */

    private final Collection<X509Certificate> trustedCerts;

    private final PKIXBuilderParameters pkixParams;

    // note that we need separate validator for client and server due to

    // the different extension checks. They are initialized lazily on demand.

    private volatile Validator clientValidator, serverValidator;

    X509TrustManagerImpl(String validatorType,

            Collection<X509Certificate> trustedCerts) {

        this.validatorType = validatorType;

        this.pkixParams = null;

        if (trustedCerts == null) {

            trustedCerts = Collections.<X509Certificate>emptySet();

        }

        this.trustedCerts = trustedCerts;

        }

    }

    X509TrustManagerImpl(String validatorType, PKIXBuilderParameters params) {

        this.validatorType = validatorType;

        this.pkixParams = params;

        // create server validator eagerly so that we can conveniently

        // get the trusted certificates

        // clients need it anyway eventually, and servers will not mind

        // the little extra footprint

        Validator v = getValidator(Validator.VAR_TLS_SERVER);

        trustedCerts = v.getTrustedCertificates();

        serverValidator = v;

        }

    }

    @Override

    public void checkClientTrusted(X509Certificate[] chain, String authType)

            throws CertificateException {

        checkTrusted(chain, authType, (Socket)null, true);

    }

    @Override

    public void checkServerTrusted(X509Certificate[] chain, String authType)

            throws CertificateException {

        checkTrusted(chain, authType, (Socket)null, false);

    }

    @Override

    public X509Certificate[] getAcceptedIssuers() {

        X509Certificate[] certsArray = new X509Certificate[trustedCerts.size()];

        trustedCerts.toArray(certsArray);

        return certsArray;

    }

    @Override

    public void checkClientTrusted(X509Certificate[] chain, String authType,

                Socket socket) throws CertificateException {

        checkTrusted(chain, authType, socket, true);

    }

    @Override

    public void checkServerTrusted(X509Certificate[] chain, String authType,

            Socket socket) throws CertificateException {

        checkTrusted(chain, authType, socket, false);

    }

    @Override

    public void checkClientTrusted(X509Certificate[] chain, String authType,

            SSLEngine engine) throws CertificateException {

        checkTrusted(chain, authType, engine, true);

    }

    @Override

    public void checkServerTrusted(X509Certificate[] chain, String authType,

            SSLEngine engine) throws CertificateException {

        checkTrusted(chain, authType, engine, false);

    }

    private Validator checkTrustedInit(X509Certificate[] chain,

                                        String authType, boolean isClient) {

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

            throw new IllegalArgumentException(

                "null or zero-length certificate chain");

        }

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

            throw new IllegalArgumentException(

                "null or zero-length authentication type");

        }

        Validator v = null;

        if (isClient) {

            v = clientValidator;

            if (v == null) {

                synchronized (this) {

                    v = clientValidator;

                    if (v == null) {

                        v = getValidator(Validator.VAR_TLS_CLIENT);

                        clientValidator = v;

                    }

                }

            }

        } else {

            // assume double checked locking with a volatile flag works

            // (guaranteed under the new Tiger memory model)

            v = serverValidator;

            if (v == null) {

                synchronized (this) {

                    v = serverValidator;

                    if (v == null) {

                        v = getValidator(Validator.VAR_TLS_SERVER);

                        serverValidator = v;

                    }

                }

            }

        }

        return v;

    }

    private void checkTrusted(X509Certificate[] chain, String authType,

                Socket socket, boolean isClient) throws CertificateException {

        Validator v = checkTrustedInit(chain, authType, isClient);

        X509Certificate[] trustedChain = null;

        if ((socket != null) && socket.isConnected() &&

                                        (socket instanceof SSLSocket)) {

            SSLSocket sslSocket = (SSLSocket)socket;

            SSLSession session = sslSocket.getHandshakeSession();

            if (session == null) {

                throw new CertificateException("No handshake session");

            }

            // create the algorithm constraints

            boolean isExtSession = (session instanceof ExtendedSSLSession);

                ExtendedSSLSession extSession = (ExtendedSSLSession)session;

                String[] localSupportedSignAlgs =

                        extSession.getLocalSupportedSignatureAlgorithms();

                constraints = new SSLAlgorithmConstraints(

                                sslSocket, localSupportedSignAlgs, false);

            } else {

                constraints = new SSLAlgorithmConstraints(sslSocket, false);

            }

            // Grab any stapled OCSP responses for use in validation

            List<byte[]> responseList = Collections.emptyList();

            if (!isClient && isExtSession) {

                responseList =

                        ((ExtendedSSLSession)session).getStatusResponses();

            }

            trustedChain = validate(v, chain, responseList,

                    constraints, isClient ? null : authType);

            // check if EE certificate chains to a public root CA (as

            // pre-installed in cacerts)

            // check endpoint identity

            String identityAlg = sslSocket.getSSLParameters().

                    getEndpointIdentificationAlgorithm();

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

                checkIdentity(session, trustedChain[0], identityAlg, isClient,

                        getRequestedServerNames(socket), chainsToPublicCA);

            }

        } else {

            trustedChain = validate(v, chain, Collections.emptyList(),

                    null, isClient ? null : authType);

        }

        }

    }

    private void checkTrusted(X509Certificate[] chain, String authType,

            SSLEngine engine, boolean isClient) throws CertificateException {

        Validator v = checkTrustedInit(chain, authType, isClient);

        X509Certificate[] trustedChain = null;

        if (engine != null) {

            SSLSession session = engine.getHandshakeSession();

            if (session == null) {

                throw new CertificateException("No handshake session");

            }

            // create the algorithm constraints

            boolean isExtSession = (session instanceof ExtendedSSLSession);

                ExtendedSSLSession extSession = (ExtendedSSLSession)session;

                String[] localSupportedSignAlgs =

                        extSession.getLocalSupportedSignatureAlgorithms();

                constraints = new SSLAlgorithmConstraints(

                                engine, localSupportedSignAlgs, false);

            } else {

                constraints = new SSLAlgorithmConstraints(engine, false);

            }

            // Grab any stapled OCSP responses for use in validation

            List<byte[]> responseList = Collections.emptyList();

            if (!isClient && isExtSession) {

                responseList =

                        ((ExtendedSSLSession)session).getStatusResponses();

            }

            trustedChain = validate(v, chain, responseList,

                    constraints, isClient ? null : authType);

            // check if EE certificate chains to a public root CA (as

            // pre-installed in cacerts)

            // check endpoint identity

            String identityAlg = engine.getSSLParameters().

                    getEndpointIdentificationAlgorithm();

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

                checkIdentity(session, trustedChain[0], identityAlg, isClient,

                        getRequestedServerNames(engine), chainsToPublicCA);

            }

        } else {

            trustedChain = validate(v, chain, Collections.emptyList(),

                    null, isClient ? null : authType);

        }

        }

    }

    private Validator getValidator(String variant) {

        Validator v;

        if (pkixParams == null) {

            v = Validator.getInstance(validatorType, variant, trustedCerts);

        } else {

            v = Validator.getInstance(validatorType, variant, pkixParams);

        }

        return v;

    }

    private static X509Certificate[] validate(Validator v,

            X509Certificate[] chain, List<byte[]> responseList,

            AlgorithmConstraints constraints, String authType)

            throws CertificateException {

        Object o = JsseJce.beginFipsProvider();

        try {

            return v.validate(chain, null, responseList, constraints, authType);

        } finally {

            JsseJce.endFipsProvider(o);

        }

    }

    // Get string representation of HostName from a list of server names.

    //

    // We are only accepting host_name name type in the list.

    private static String getHostNameInSNI(List<SNIServerName> sniNames) {

        SNIHostName hostname = null;

        for (SNIServerName sniName : sniNames) {

            if (sniName.getType() != StandardConstants.SNI_HOST_NAME) {

                continue;

            }

            if (sniName instanceof SNIHostName) {

                hostname = (SNIHostName)sniName;

            } else {

                try {

                    hostname = new SNIHostName(sniName.getEncoded());

                } catch (IllegalArgumentException iae) {

                    // unlikely to happen, just in case ...

                    }

                }

            }

            // no more than server name of the same name type

            break;

        }

        if (hostname != null) {

            return hostname.getAsciiName();

        }

        return null;

    }

    // Also used by X509KeyManagerImpl

    static List<SNIServerName> getRequestedServerNames(Socket socket) {

        if (socket != null && socket.isConnected() &&

                                        socket instanceof SSLSocket) {

            SSLSocket sslSocket = (SSLSocket)socket;

            SSLSession session = sslSocket.getHandshakeSession();

            if (session != null && (session instanceof ExtendedSSLSession)) {

                ExtendedSSLSession extSession = (ExtendedSSLSession)session;

                return extSession.getRequestedServerNames();

            }

        }

        return Collections.<SNIServerName>emptyList();

    }

    // Also used by X509KeyManagerImpl

    static List<SNIServerName> getRequestedServerNames(SSLEngine engine) {

        if (engine != null) {

            SSLSession session = engine.getHandshakeSession();

            if (session != null && (session instanceof ExtendedSSLSession)) {

                ExtendedSSLSession extSession = (ExtendedSSLSession)session;

                return extSession.getRequestedServerNames();

            }

        }

        return Collections.<SNIServerName>emptyList();

    }

    /*

     * Per RFC 6066, if an application negotiates a server name using an

     * application protocol and then upgrades to TLS, and if a server_name

     * extension is sent, then the extension SHOULD contain the same name

     * that was negotiated in the application protocol.  If the server_name

     * is established in the TLS session handshake, the client SHOULD NOT

     * attempt to request a different server name at the application layer.

     *

     * According to the above spec, we only need to check either the identity

     * in server_name extension or the peer host of the connection.  Peer host

     * is not always a reliable fully qualified domain name. The HostName in

     * server_name extension is more reliable than peer host. So we prefer

     * the identity checking aginst the server_name extension if present, and

     * may failove to peer host checking.

     */

    private static void checkIdentity(SSLSession session,

            X509Certificate cert,

            String algorithm,

            boolean isClient,

            List<SNIServerName> sniNames,

            boolean chainsToPublicCA) throws CertificateException {

        boolean identifiable = false;

        String peerHost = session.getPeerHost();

        if (isClient) {

            String hostname = getHostNameInSNI(sniNames);

            if (hostname != null) {

                try {

                    checkIdentity(hostname, cert, algorithm, chainsToPublicCA);

                    identifiable = true;

                } catch (CertificateException ce) {

                    if (hostname.equalsIgnoreCase(peerHost)) {

                        throw ce;

                    }

                    // otherwisw, failover to check peer host

                }

            }

        }

        if (!identifiable) {

            checkIdentity(peerHost, cert, algorithm, chainsToPublicCA);

        }

    }

    /*

     * Identify the peer by its certificate and hostname.

     *

     * Lifted from sun.net.www.protocol.https.HttpsClient.

     */

    static void checkIdentity(String hostname, X509Certificate cert,

            String algorithm) throws CertificateException {

        checkIdentity(hostname, cert, algorithm, false);

    }

    private static void checkIdentity(String hostname, X509Certificate cert,

            String algorithm, boolean chainsToPublicCA)

            throws CertificateException {

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

            // if IPv6 strip off the "[]"

            if ((hostname != null) && hostname.startsWith("[") &&

                    hostname.endsWith("]")) {

                hostname = hostname.substring(1, hostname.length() - 1);

            }

            if (algorithm.equalsIgnoreCase("HTTPS")) {

                HostnameChecker.getInstance(HostnameChecker.TYPE_TLS).match(

                        hostname, cert, chainsToPublicCA);

            } else if (algorithm.equalsIgnoreCase("LDAP") ||

                    algorithm.equalsIgnoreCase("LDAPS")) {

                HostnameChecker.getInstance(HostnameChecker.TYPE_LDAP).match(

                        hostname, cert, chainsToPublicCA);

            } else {

                throw new CertificateException(

                        "Unknown identification algorithm: " + algorithm);

            }

        }

    }

}