/*

 * Copyright (c) 2012, 2013, 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.*;

import java.security.AccessController;

import java.security.MessageDigest;

import java.security.NoSuchAlgorithmException;

import java.security.PrivilegedAction;

import java.security.cert.X509Certificate;

import java.security.cert.CertificateException;

import java.util.*;

import sun.security.x509.X509CertImpl;

/**

 * A utility class to check if a certificate is untrusted. This is an internal

 * mechanism that explicitly marks a certificate as untrusted, normally in the

 * case that a certificate is known to be used for malicious reasons.

 *

 * <b>Attention</b>: This check is NOT meant to replace the standard PKI-defined

 * validation check, neither is it used as an alternative to CRL.

 */

public final class UntrustedCertificates {

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

    private static final String ALGORITHM_KEY = "Algorithm";

    private static final Properties props = new Properties();

    private static final String algorithm;

    static {

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

            @Override

            public Void run() {

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

                        "lib/security/blacklisted.certs");

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

                    props.load(fin);

                    // It's said that the fingerprint could contain colons

                    for (Map.Entry<Object,Object> e: props.entrySet()) {

                        e.setValue(stripColons(e.getValue()));

                    }

                } catch (IOException fnfe) {

                    if (debug != null) {

                        debug.println("Error parsing blacklisted.certs");

                    }

                }

                return null;

            }

        });

        algorithm = props.getProperty(ALGORITHM_KEY);

    }

    private static String stripColons(Object input) {

        String s = (String)input;

        char[] letters = s.toCharArray();

        int pos = 0;

        for (int i = 0; i < letters.length; i++) {

            if (letters[i] != ':') {

                if (i != pos) {

                    letters[pos] = letters[i];

                }

                pos++;

            }

        }

        if (pos == letters.length) return s;

        else return new String(letters, 0, pos);

    }

    /**

     * Checks if a certificate is untrusted.

     *

     * @param cert the certificate to check

     * @return true if the certificate is untrusted.

     */

    public static boolean isUntrusted(X509Certificate cert) {

        if (algorithm == null) {

            return false;

        }

        String key;

        if (cert instanceof X509CertImpl) {

            key = ((X509CertImpl)cert).getFingerprint(algorithm);

        } else {

            try {

                key = new X509CertImpl(cert.getEncoded()).getFingerprint(algorithm);

            } catch (CertificateException cee) {

                return false;

            }

        }

        return props.containsKey(key);

    }

    private UntrustedCertificates() {}

}