/*

 * Copyright (c) 1998, 2018, 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.provider;

import java.io.*;

import java.util.*;

import java.security.cert.*;

import sun.security.util.Pem;

import sun.security.pkcs.PKCS7;

import sun.security.provider.certpath.X509CertPath;

import sun.security.provider.certpath.X509CertificatePair;

import sun.security.util.DerValue;

import sun.security.util.Cache;

import java.util.Base64;

import sun.security.pkcs.ParsingException;

/**

 * This class defines a certificate factory for X.509 v3 certificates {@literal &}

 * certification paths, and X.509 v2 certificate revocation lists (CRLs).

 *

 * @author Jan Luehe

 * @author Hemma Prafullchandra

 * @author Sean Mullan

 *

 *

 * @see java.security.cert.CertificateFactorySpi

 * @see java.security.cert.Certificate

 * @see java.security.cert.CertPath

 * @see java.security.cert.CRL

 * @see java.security.cert.X509Certificate

 * @see java.security.cert.X509CRL

 * @see sun.security.x509.X509CertImpl

 * @see sun.security.x509.X509CRLImpl

 */

public class X509Factory extends CertificateFactorySpi {

    public static final String BEGIN_CERT = "-----BEGIN CERTIFICATE-----";

    public static final String END_CERT = "-----END CERTIFICATE-----";

    private static final int ENC_MAX_LENGTH = 4096 * 1024; // 4 MB MAX

    private static final Cache<Object, X509CertImpl> certCache

        = Cache.newSoftMemoryCache(750);

    private static final Cache<Object, X509CRLImpl> crlCache

        = Cache.newSoftMemoryCache(750);

    /**

     * Generates an X.509 certificate object and initializes it with

     * the data read from the input stream <code>is</code>.

     *

     * @param is an input stream with the certificate data.

     *

     * @return an X.509 certificate object initialized with the data

     * from the input stream.

     *

     * @exception CertificateException on parsing errors.

     */

    @Override

    public Certificate engineGenerateCertificate(InputStream is)

        throws CertificateException

    {

        if (is == null) {

            // clear the caches (for debugging)

            certCache.clear();

            X509CertificatePair.clearCache();

            throw new CertificateException("Missing input stream");

        }

        try {

            byte[] encoding = readOneBlock(is);

            if (encoding != null) {

                X509CertImpl cert = getFromCache(certCache, encoding);

                if (cert != null) {

                    return cert;

                }

                cert = new X509CertImpl(encoding);

                addToCache(certCache, cert.getEncodedInternal(), cert);

                return cert;

            } else {

                throw new IOException("Empty input");

            }

        } catch (IOException ioe) {

            throw new CertificateException("Could not parse certificate: " +

                    ioe.toString(), ioe);

        }

    }

    /**

     * Read from the stream until length bytes have been read or EOF has

     * been reached. Return the number of bytes actually read.

     */

    private static int readFully(InputStream in, ByteArrayOutputStream bout,

            int length) throws IOException {

        int read = 0;

        byte[] buffer = new byte[2048];

        while (length > 0) {

            int n = in.read(buffer, 0, length<2048?length:2048);

            if (n <= 0) {

                break;

            }

            bout.write(buffer, 0, n);

            read += n;

            length -= n;

        }

        return read;

    }

    /**

     * Return an interned X509CertImpl for the given certificate.

     * If the given X509Certificate or X509CertImpl is already present

     * in the cert cache, the cached object is returned. Otherwise,

     * if it is a X509Certificate, it is first converted to a X509CertImpl.

     * Then the X509CertImpl is added to the cache and returned.

     *

     * Note that all certificates created via generateCertificate(InputStream)

     * are already interned and this method does not need to be called.

     * It is useful for certificates that cannot be created via

     * generateCertificate() and for converting other X509Certificate

     * implementations to an X509CertImpl.

     *

     * @param c The source X509Certificate

     * @return An X509CertImpl object that is either a cached certificate or a

     *      newly built X509CertImpl from the provided X509Certificate

     * @throws CertificateException if failures occur while obtaining the DER

     *      encoding for certificate data.

     */

    public static synchronized X509CertImpl intern(X509Certificate c)

            throws CertificateException {

        if (c == null) {

            return null;

        }

        boolean isImpl = c instanceof X509CertImpl;

        byte[] encoding;

        if (isImpl) {

            encoding = ((X509CertImpl)c).getEncodedInternal();

        } else {

            encoding = c.getEncoded();

        }

        X509CertImpl newC = getFromCache(certCache, encoding);

        if (newC != null) {

            return newC;

        }

        if (isImpl) {

            newC = (X509CertImpl)c;

        } else {

            newC = new X509CertImpl(encoding);

            encoding = newC.getEncodedInternal();

        }

        addToCache(certCache, encoding, newC);

        return newC;

    }

    /**

     * Return an interned X509CRLImpl for the given certificate.

     * For more information, see intern(X509Certificate).

     *

     * @param c The source X509CRL

     * @return An X509CRLImpl object that is either a cached CRL or a

     *      newly built X509CRLImpl from the provided X509CRL

     * @throws CRLException if failures occur while obtaining the DER

     *      encoding for CRL data.

     */

    public static synchronized X509CRLImpl intern(X509CRL c)

            throws CRLException {

        if (c == null) {

            return null;

        }

        boolean isImpl = c instanceof X509CRLImpl;

        byte[] encoding;

        if (isImpl) {

            encoding = ((X509CRLImpl)c).getEncodedInternal();

        } else {

            encoding = c.getEncoded();

        }

        X509CRLImpl newC = getFromCache(crlCache, encoding);

        if (newC != null) {

            return newC;

        }

        if (isImpl) {

            newC = (X509CRLImpl)c;

        } else {

            newC = new X509CRLImpl(encoding);

            encoding = newC.getEncodedInternal();

        }

        addToCache(crlCache, encoding, newC);

        return newC;

    }

    /**

     * Get the X509CertImpl or X509CRLImpl from the cache.

     */

    private static synchronized <K,V> V getFromCache(Cache<K,V> cache,

            byte[] encoding) {

        Object key = new Cache.EqualByteArray(encoding);

        return cache.get(key);

    }

    /**

     * Add the X509CertImpl or X509CRLImpl to the cache.

     */

    private static synchronized <V> void addToCache(Cache<Object, V> cache,

            byte[] encoding, V value) {

        if (encoding.length > ENC_MAX_LENGTH) {

            return;

        }

        Object key = new Cache.EqualByteArray(encoding);

        cache.put(key, value);

    }

    /**

     * Generates a <code>CertPath</code> object and initializes it with

     * the data read from the <code>InputStream</code> inStream. The data

     * is assumed to be in the default encoding.

     *

     * @param inStream an <code>InputStream</code> containing the data

     * @return a <code>CertPath</code> initialized with the data from the

     *   <code>InputStream</code>

     * @exception CertificateException if an exception occurs while decoding

     * @since 1.4

     */

    @Override

    public CertPath engineGenerateCertPath(InputStream inStream)

        throws CertificateException

    {

        if (inStream == null) {

            throw new CertificateException("Missing input stream");

        }

        try {

            byte[] encoding = readOneBlock(inStream);

            if (encoding != null) {

                return new X509CertPath(new ByteArrayInputStream(encoding));

            } else {

                throw new IOException("Empty input");

            }

        } catch (IOException ioe) {

            throw new CertificateException(ioe.getMessage());

        }

    }

    /**

     * Generates a <code>CertPath</code> object and initializes it with

     * the data read from the <code>InputStream</code> inStream. The data

     * is assumed to be in the specified encoding.

     *

     * @param inStream an <code>InputStream</code> containing the data

     * @param encoding the encoding used for the data

     * @return a <code>CertPath</code> initialized with the data from the

     *   <code>InputStream</code>

     * @exception CertificateException if an exception occurs while decoding or

     *   the encoding requested is not supported

     * @since 1.4

     */

    @Override

    public CertPath engineGenerateCertPath(InputStream inStream,

        String encoding) throws CertificateException

    {

        if (inStream == null) {

            throw new CertificateException("Missing input stream");

        }

        try {

            byte[] data = readOneBlock(inStream);

            if (data != null) {

                return new X509CertPath(new ByteArrayInputStream(data), encoding);

            } else {

                throw new IOException("Empty input");

            }

        } catch (IOException ioe) {

            throw new CertificateException(ioe.getMessage());

        }

    }

    /**

     * Generates a <code>CertPath</code> object and initializes it with

     * a <code>List</code> of <code>Certificate</code>s.

     * <p>

     * The certificates supplied must be of a type supported by the

     * <code>CertificateFactory</code>. They will be copied out of the supplied

     * <code>List</code> object.

     *

     * @param certificates a <code>List</code> of <code>Certificate</code>s

     * @return a <code>CertPath</code> initialized with the supplied list of

     *   certificates

     * @exception CertificateException if an exception occurs

     * @since 1.4

     */

    @Override

    public CertPath

        engineGenerateCertPath(List<? extends Certificate> certificates)

        throws CertificateException

    {

        return(new X509CertPath(certificates));

    }

    /**

     * Returns an iteration of the <code>CertPath</code> encodings supported

     * by this certificate factory, with the default encoding first.

     * <p>

     * Attempts to modify the returned <code>Iterator</code> via its

     * <code>remove</code> method result in an

     * <code>UnsupportedOperationException</code>.

     *

     * @return an <code>Iterator</code> over the names of the supported

     *         <code>CertPath</code> encodings (as <code>String</code>s)

     * @since 1.4

     */

    @Override

    public Iterator<String> engineGetCertPathEncodings() {

        return(X509CertPath.getEncodingsStatic());

    }

    /**

     * Returns a (possibly empty) collection view of X.509 certificates read

     * from the given input stream <code>is</code>.

     *

     * @param is the input stream with the certificates.

     *

     * @return a (possibly empty) collection view of X.509 certificate objects

     * initialized with the data from the input stream.

     *

     * @exception CertificateException on parsing errors.

     */

    @Override

    public Collection<? extends java.security.cert.Certificate>

            engineGenerateCertificates(InputStream is)

            throws CertificateException {

        if (is == null) {

            throw new CertificateException("Missing input stream");

        }

        try {

            return parseX509orPKCS7Cert(is);

        } catch (IOException ioe) {

            throw new CertificateException(ioe);

        }

    }

    /**

     * Generates an X.509 certificate revocation list (CRL) object and

     * initializes it with the data read from the given input stream

     * <code>is</code>.

     *

     * @param is an input stream with the CRL data.

     *

     * @return an X.509 CRL object initialized with the data

     * from the input stream.

     *

     * @exception CRLException on parsing errors.

     */

    @Override

    public CRL engineGenerateCRL(InputStream is)

        throws CRLException

    {

        if (is == null) {

            // clear the cache (for debugging)

            crlCache.clear();

            throw new CRLException("Missing input stream");

        }

        try {

            byte[] encoding = readOneBlock(is);

            if (encoding != null) {

                X509CRLImpl crl = getFromCache(crlCache, encoding);

                if (crl != null) {

                    return crl;

                }

                crl = new X509CRLImpl(encoding);

                addToCache(crlCache, crl.getEncodedInternal(), crl);

                return crl;

            } else {

                throw new IOException("Empty input");

            }

        } catch (IOException ioe) {

            throw new CRLException(ioe.getMessage());

        }

    }

    /**

     * Returns a (possibly empty) collection view of X.509 CRLs read

     * from the given input stream <code>is</code>.

     *

     * @param is the input stream with the CRLs.

     *

     * @return a (possibly empty) collection view of X.509 CRL objects

     * initialized with the data from the input stream.

     *

     * @exception CRLException on parsing errors.

     */

    @Override

    public Collection<? extends java.security.cert.CRL> engineGenerateCRLs(

            InputStream is) throws CRLException

    {

        if (is == null) {

            throw new CRLException("Missing input stream");

        }

        try {

            return parseX509orPKCS7CRL(is);

        } catch (IOException ioe) {

            throw new CRLException(ioe.getMessage());

        }

    }

    /*

     * Parses the data in the given input stream as a sequence of DER

     * encoded X.509 certificates (in binary or base 64 encoded format) OR

     * as a single PKCS#7 encoded blob (in binary or base64 encoded format).

     */

    private Collection<? extends java.security.cert.Certificate>

        parseX509orPKCS7Cert(InputStream is)

        throws CertificateException, IOException

    {

        int peekByte;

        byte[] data;

        PushbackInputStream pbis = new PushbackInputStream(is);

        Collection<X509CertImpl> coll = new ArrayList<>();

        // Test the InputStream for end-of-stream.  If the stream's

        // initial state is already at end-of-stream then return

        // an empty collection.  Otherwise, push the byte back into the

        // stream and let readOneBlock look for the first certificate.

        peekByte = pbis.read();

        if (peekByte == -1) {

            return new ArrayList<>(0);

        } else {

            pbis.unread(peekByte);

            data = readOneBlock(pbis);

        }

        // If we end up with a null value after reading the first block

        // then we know the end-of-stream has been reached and no certificate

        // data has been found.

        if (data == null) {

            throw new CertificateException("No certificate data found");

        }

        try {

            PKCS7 pkcs7 = new PKCS7(data);

            X509Certificate[] certs = pkcs7.getCertificates();

            // certs are optional in PKCS #7

            if (certs != null) {

                return Arrays.asList(certs);

            } else {

                // no certificates provided

                return new ArrayList<>(0);

            }

        } catch (ParsingException e) {

            while (data != null) {

                coll.add(new X509CertImpl(data));

                data = readOneBlock(pbis);

            }

        }

        return coll;

    }

    /*

     * Parses the data in the given input stream as a sequence of DER encoded

     * X.509 CRLs (in binary or base 64 encoded format) OR as a single PKCS#7

     * encoded blob (in binary or base 64 encoded format).

     */

    private Collection<? extends java.security.cert.CRL>

        parseX509orPKCS7CRL(InputStream is)

        throws CRLException, IOException

    {

        int peekByte;

        byte[] data;

        PushbackInputStream pbis = new PushbackInputStream(is);

        Collection<X509CRLImpl> coll = new ArrayList<>();

        // Test the InputStream for end-of-stream.  If the stream's

        // initial state is already at end-of-stream then return

        // an empty collection.  Otherwise, push the byte back into the

        // stream and let readOneBlock look for the first CRL.

        peekByte = pbis.read();

        if (peekByte == -1) {

            return new ArrayList<>(0);

        } else {

            pbis.unread(peekByte);

            data = readOneBlock(pbis);

        }

        // If we end up with a null value after reading the first block

        // then we know the end-of-stream has been reached and no CRL

        // data has been found.

        if (data == null) {

            throw new CRLException("No CRL data found");