/*

 * 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

 * particular file as subject to the "Classpath" exception as provided

 *

 * 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.

 *

 */

package sun.security.ssl;

import java.util.*;

import java.security.*;

import java.security.cert.*;

import javax.net.ssl.*;

import com.sun.net.ssl.internal.ssl.X509ExtendedTrustManager;

import sun.security.validator.*;

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>

 *

 * 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

 * @author Xuelei Fan

 */

final class X509TrustManagerImpl extends X509ExtendedTrustManager

        implements X509TrustManager {

    /**

     * Flag indicating whether to enable revocation check for the PKIX trust

     * manager. Typically, this will only work if the PKIX implementation

     * supports CRL distribution points as we do not manually setup CertStores.

     */

    private final static boolean checkRevocation =

        Debug.getBooleanProperty("com.sun.net.ssl.checkRevocation", false);

    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;

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

    X509TrustManagerImpl(String validatorType, KeyStore ks)

            throws KeyStoreException {

        this.validatorType = validatorType;

        this.pkixParams = null;

        if (ks == null) {

            trustedCerts = Collections.<X509Certificate>emptySet();

        } else {

            trustedCerts = KeyStores.getTrustedCerts(ks);

        }

        showTrustedCerts();

    }

    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;

        showTrustedCerts();

    }

    private void showTrustedCerts() {

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

            for (X509Certificate cert : trustedCerts) {

                System.out.println("adding as trusted cert:");

                System.out.println("  Subject: "

                                        + cert.getSubjectX500Principal());

                System.out.println("  Issuer:  "

                                        + cert.getIssuerX500Principal());

                System.out.println("  Algorithm: "

                                        + cert.getPublicKey().getAlgorithm()

                                        + "; Serial number: 0x"

                                        + cert.getSerialNumber().toString(16));

                System.out.println("  Valid from "

                                        + cert.getNotBefore() + " until "

                                        + cert.getNotAfter());

                System.out.println();

            }

        }

    }

    private Validator getValidator(String variant) {

        Validator v;

        if (pkixParams == null) {

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

            // if the PKIX validator is created from a KeyStore,

            // disable revocation checking

            if (v instanceof PKIXValidator) {

                PKIXValidator pkixValidator = (PKIXValidator)v;

                pkixValidator.getParameters().setRevocationEnabled

                                                            (checkRevocation);

            }

        } else {

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

        }

        return v;

    }

    private static X509Certificate[] validate(Validator v,

            X509Certificate[] chain, String authType) throws CertificateException {

        Object o = JsseJce.beginFipsProvider();

        try {

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

        } finally {

            JsseJce.endFipsProvider(o);

        }

    }

    /**

     * Returns true if the client certificate can be trusted.

     *

     * @param chain certificates which establish an identity for the client.

     *      Chains of arbitrary length are supported, and certificates

     *      marked internally as trusted will short-circuit signature checks.

     * @throws IllegalArgumentException if null or zero-length chain

     *         is passed in for the chain parameter or if null or zero-length

     *         string is passed in for the authType parameter.

     * @throws CertificateException if the certificate chain is not trusted

     *      by this TrustManager.

     */

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

            throws CertificateException {

        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");

        }

        // assume double checked locking with a volatile flag works

        // (guaranteed under the new Tiger memory model)

        Validator v = clientValidator;

        if (v == null) {

            synchronized (this) {

                v = clientValidator;

                if (v == null) {

                    v = getValidator(Validator.VAR_TLS_CLIENT);

                    clientValidator = v;

                }

            }

        }

        X509Certificate[] trustedChain = validate(v, chain, null);

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

            System.out.println("Found trusted certificate:");

            System.out.println(trustedChain[trustedChain.length - 1]);

        }

    }

    /**

     * Returns true if the server certifcate can be trusted.

     *

     * @param chain certificates which establish an identity for the server.

     *      Chains of arbitrary length are supported, and certificates

     *      marked internally as trusted will short-circuit signature checks.

     * @throws IllegalArgumentException if null or zero-length chain

     *         is passed in for the chain parameter or if null or zero-length

     *         string is passed in for the authType parameter.

     * @throws CertificateException if the certificate chain is not trusted

     *      by this TrustManager.

     */

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

            throws CertificateException {

        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");

        }

        // assume double checked locking with a volatile flag works

        // (guaranteed under the new Tiger memory model)

        Validator v = serverValidator;

        if (v == null) {

            synchronized (this) {

                v = serverValidator;

                if (v == null) {

                    v = getValidator(Validator.VAR_TLS_SERVER);

                    serverValidator = v;

                }

            }

        }

        X509Certificate[] trustedChain = validate(v, chain, authType);

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

            System.out.println("Found trusted certificate:");

            System.out.println(trustedChain[trustedChain.length - 1]);

        }

    }

    /**

     * Returns a list of CAs accepted to authenticate entities for the

     * specified purpose.

     *

     * @param purpose activity for which CAs should be trusted

     * @return list of CAs accepted for authenticating such tasks

     */

    public X509Certificate[] getAcceptedIssuers() {

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

        trustedCerts.toArray(certsArray);

        return certsArray;

    }

    /**

     * Given the partial or complete certificate chain provided by the

     * peer, check its identity and build a certificate path to a trusted

     * root, return if it can be validated and is trusted for client SSL

     * authentication based on the authentication type.

     */

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

        String hostname, String algorithm) throws CertificateException {

        checkClientTrusted(chain, authType);

        checkIdentity(hostname, chain[0], algorithm);

    }

    /**

     * Given the partial or complete certificate chain provided by the

     * peer, check its identity and build a certificate path to a trusted

     * root, return if it can be validated and is trusted for server SSL

     * authentication based on the authentication type.

     */

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

        String hostname, String algorithm) throws CertificateException {

        checkServerTrusted(chain, authType);

        checkIdentity(hostname, chain[0], algorithm);

    }

    // Identify the peer by its certificate and hostname.

    private void checkIdentity(String hostname, X509Certificate cert,

        String algorithm) 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);

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

                HostnameChecker.getInstance(HostnameChecker.TYPE_LDAP).match(

                        hostname, cert);

            } else {

                throw new CertificateException(

                        "Unknown identification algorithm: " + algorithm);

            }

        }

    }

}