/*

 * Copyright (c) 2016, 2020, 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.util;

import java.io.File;

import java.io.FileInputStream;

import java.security.AccessController;

import java.security.KeyStore;

import java.security.PrivilegedAction;

import java.security.cert.X509Certificate;

import java.util.Collections;

import java.util.Enumeration;

import java.util.HashSet;

import java.util.Set;

import javax.security.auth.x500.X500Principal;

import sun.security.x509.X509CertImpl;

/**

 * The purpose of this class is to determine the trust anchor certificates is in

 * the cacerts file.  This is used for PKIX CertPath checking.

 */

public class AnchorCertificates {

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

    private static final String HASH = "SHA-256";

    private static Set<String> certs = Collections.emptySet();

    private static Set<X500Principal> certIssuers = Collections.emptySet();

    static  {

        AccessController.doPrivileged(new PrivilegedAction<Void>() {

            @Override

            public Void run() {

                File f = new File(System.getProperty("java.home"),

                        "lib/security/cacerts");

                KeyStore cacerts;

                try {

                    cacerts = KeyStore.getInstance("JKS");

                    try (FileInputStream fis = new FileInputStream(f)) {

                        cacerts.load(fis, null);

                        certs = new HashSet<>();

                        certIssuers = new HashSet<>();

                        Enumeration<String> list = cacerts.aliases();

                        while (list.hasMoreElements()) {

                            String alias = list.nextElement();

                            // Check if this cert is labeled a trust anchor.

                            if (alias.contains(" [jdk")) {

                                X509Certificate cert = (X509Certificate) cacerts

                                        .getCertificate(alias);

                                certs.add(X509CertImpl.getFingerprint(HASH, cert));

                                certIssuers.add(cert.getSubjectX500Principal());

                            }

                        }

                    }

                } catch (Exception e) {

                    if (debug != null) {

                        debug.println("Error parsing cacerts");

                        e.printStackTrace();

                    }

                }

                return null;

            }

        });

    }

    /**

     * Checks if a certificate is a JDK trust anchor.

     *

     * @param cert the certificate to check

     * @return true if the certificate is a JDK trust anchor

     */

    public static boolean contains(X509Certificate cert) {

        String key = X509CertImpl.getFingerprint(HASH, cert);

        boolean result = certs.contains(key);

        if (result && debug != null) {

            debug.println("AnchorCertificate.contains: matched " +

                    cert.getSubjectDN());

        }

        return result;

    }

    /**

     * Checks if a JDK trust anchor is the issuer of a certificate.

     *

     * @param cert the certificate to check

     * @return true if the certificate is issued by a trust anchor

     */

    public static boolean issuerOf(X509Certificate cert) {

        return certIssuers.contains(cert.getIssuerX500Principal());

    }

    private AnchorCertificates() {}

}