https://openjdk.java.net/ 
/*
 * Copyright (c) 2000, 2012, 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
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 */

package sun.security.provider.certpath;

import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.security.cert.CertificateEncodingException;
import java.security.cert.Certificate;
import java.security.cert.CertificateException;
import java.security.cert.CertificateFactory;
import java.security.cert.CertPath;
import java.security.cert.X509Certificate;
import java.util.*;

import sun.security.pkcs.ContentInfo;
import sun.security.pkcs.PKCS7;
import sun.security.pkcs.SignerInfo;
import sun.security.x509.AlgorithmId;
import sun.security.util.DerValue;
import sun.security.util.DerOutputStream;
import sun.security.util.DerInputStream;


A CertPath (certification path) consisting exclusively of X509Certificates. 

By convention, X.509 CertPaths are stored from target
to trust anchor.
That is, the issuer of one certificate is the subject of the following
one. However, unvalidated X.509 CertPaths may not follow
this convention. PKIX CertPathValidators will detect any
departure from this convention and throw a
CertPathValidatorException.

Author:     Yassir Elley
Since:      1.4
/**
 * A {@link java.security.cert.CertPath CertPath} (certification path)
 * consisting exclusively of
 * {@link java.security.cert.X509Certificate X509Certificate}s.
 * <p>
 * By convention, X.509 <code>CertPath</code>s are stored from target
 * to trust anchor.
 * That is, the issuer of one certificate is the subject of the following
 * one. However, unvalidated X.509 <code>CertPath</code>s may not follow
 * this convention. PKIX <code>CertPathValidator</code>s will detect any
 * departure from this convention and throw a
 * <code>CertPathValidatorException</code>.
 *
 * @author      Yassir Elley
 * @since       1.4
 */
public class X509CertPath extends CertPath {

    private static final long serialVersionUID = 4989800333263052980L;

    
List of certificates in this chain

/**
     * List of certificates in this chain
     */
    private List<X509Certificate> certs;

    
The names of our encodings.  PkiPath is the default.

/**
     * The names of our encodings.  PkiPath is the default.
     */
    private static final String COUNT_ENCODING = "count";
    private static final String PKCS7_ENCODING = "PKCS7";
    private static final String PKIPATH_ENCODING = "PkiPath";

    
List of supported encodings

/**
     * List of supported encodings
     */
    private static final Collection<String> encodingList;

    static {
        List<String> list = new ArrayList<>(2);
        list.add(PKIPATH_ENCODING);
        list.add(PKCS7_ENCODING);
        encodingList = Collections.unmodifiableCollection(list);
    }

    
Creates an X509CertPath from a List of
X509Certificates.


The certificates are copied out of the supplied List
object.

Params:
  • certs – a List of X509Certificates
Throws:
/**
     * Creates an <code>X509CertPath</code> from a <code>List</code> of
     * <code>X509Certificate</code>s.
     * <p>
     * The certificates are copied out of the supplied <code>List</code>
     * object.
     *
     * @param certs a <code>List</code> of <code>X509Certificate</code>s
     * @exception CertificateException if <code>certs</code> contains an element
     *                      that is not an <code>X509Certificate</code>
     */
    @SuppressWarnings("unchecked")
    public X509CertPath(List<? extends Certificate> certs) throws CertificateException {
        super("X.509");

        // Ensure that the List contains only X509Certificates
        //
        // Note; The certs parameter is not necessarily to be of Certificate
        // for some old code. For compatibility, to make sure the exception
        // is CertificateException, rather than ClassCastException, please
        // don't use
        //     for (Certificate obj : certs)
        for (Object obj : certs) {
            if (obj instanceof X509Certificate == false) {
                throw new CertificateException
                    ("List is not all X509Certificates: "
                    + obj.getClass().getName());
            }
        }

        // Assumes that the resulting List is thread-safe. This is true
        // because we ensure that it cannot be modified after construction
        // and the methods in the Sun JDK 1.4 implementation of ArrayList that
        // allow read-only access are thread-safe.
        this.certs = Collections.unmodifiableList(
                new ArrayList<X509Certificate>((List<X509Certificate>)certs));
    }

    
Creates an X509CertPath, reading the encoded form
from an InputStream. The data is assumed to be in
the default encoding.

Params:
  • is – the InputStream to read the data from
Throws:
/**
     * Creates an <code>X509CertPath</code>, reading the encoded form
     * from an <code>InputStream</code>. The data is assumed to be in
     * the default encoding.
     *
     * @param is the <code>InputStream</code> to read the data from
     * @exception CertificateException if an exception occurs while decoding
     */
    public X509CertPath(InputStream is) throws CertificateException {
        this(is, PKIPATH_ENCODING);
    }

    
Creates an X509CertPath, reading the encoded form
from an InputStream. The data is assumed to be in the specified
encoding.

Params:
  • is – the InputStream to read the data from
  • encoding – the encoding used
Throws:
  • CertificateException – if an exception occurs while decoding or
  the encoding requested is not supported
/**
     * Creates an <code>X509CertPath</code>, reading the encoded form
     * from an InputStream. The data is assumed to be in the specified
     * encoding.
     *
     * @param is the <code>InputStream</code> to read the data from
     * @param encoding the encoding used
     * @exception CertificateException if an exception occurs while decoding or
     *   the encoding requested is not supported
     */
    public X509CertPath(InputStream is, String encoding)
            throws CertificateException {
        super("X.509");

        switch (encoding) {
            case PKIPATH_ENCODING:
                certs = parsePKIPATH(is);
                break;
            case PKCS7_ENCODING:
                certs = parsePKCS7(is);
                break;
            default:
                throw new CertificateException("unsupported encoding");
        }
    }

    
Parse a PKIPATH format CertPath from an InputStream. Return an
unmodifiable List of the certificates.

Params:
  • is – the InputStream to read the data from
Throws:
Returns:an unmodifiable List of the certificates
/**
     * Parse a PKIPATH format CertPath from an InputStream. Return an
     * unmodifiable List of the certificates.
     *
     * @param is the <code>InputStream</code> to read the data from
     * @return an unmodifiable List of the certificates
     * @exception CertificateException if an exception occurs
     */
    private static List<X509Certificate> parsePKIPATH(InputStream is)
            throws CertificateException {
        List<X509Certificate> certList = null;
        CertificateFactory certFac = null;

        if (is == null) {
            throw new CertificateException("input stream is null");
        }

        try {
            DerInputStream dis = new DerInputStream(readAllBytes(is));
            DerValue[] seq = dis.getSequence(3);
            if (seq.length == 0) {
                return Collections.<X509Certificate>emptyList();
            }

            certFac = CertificateFactory.getInstance("X.509");
            certList = new ArrayList<X509Certificate>(seq.length);

            // append certs in reverse order (target to trust anchor)
            for (int i = seq.length-1; i >= 0; i--) {
                certList.add((X509Certificate)certFac.generateCertificate
                    (new ByteArrayInputStream(seq[i].toByteArray())));
            }

            return Collections.unmodifiableList(certList);

        } catch (IOException ioe) {
            throw new CertificateException("IOException parsing PkiPath data: "
                    + ioe, ioe);
        }
    }

    
Parse a PKCS#7 format CertPath from an InputStream. Return an
unmodifiable List of the certificates.

Params:
  • is – the InputStream to read the data from
Throws:
Returns:an unmodifiable List of the certificates
/**
     * Parse a PKCS#7 format CertPath from an InputStream. Return an
     * unmodifiable List of the certificates.
     *
     * @param is the <code>InputStream</code> to read the data from
     * @return an unmodifiable List of the certificates
     * @exception CertificateException if an exception occurs
     */
    private static List<X509Certificate> parsePKCS7(InputStream is)
            throws CertificateException {
        List<X509Certificate> certList;

        if (is == null) {
            throw new CertificateException("input stream is null");
        }

        try {
            if (is.markSupported() == false) {
                // Copy the entire input stream into an InputStream that does
                // support mark
                is = new ByteArrayInputStream(readAllBytes(is));
            }
            PKCS7 pkcs7 = new PKCS7(is);

            X509Certificate[] certArray = pkcs7.getCertificates();
            // certs are optional in PKCS #7
            if (certArray != null) {
                certList = Arrays.asList(certArray);
            } else {
                // no certs provided
                certList = new ArrayList<X509Certificate>(0);
            }
        } catch (IOException ioe) {
            throw new CertificateException("IOException parsing PKCS7 data: " +
                                        ioe);
        }
        // Assumes that the resulting List is thread-safe. This is true
        // because we ensure that it cannot be modified after construction
        // and the methods in the Sun JDK 1.4 implementation of ArrayList that
        // allow read-only access are thread-safe.
        return Collections.unmodifiableList(certList);
    }

    /*
     * Reads the entire contents of an InputStream into a byte array.
     *
     * @param is the InputStream to read from
     * @return the bytes read from the InputStream
     */
    private static byte[] readAllBytes(InputStream is) throws IOException {
        byte[] buffer = new byte[8192];
        ByteArrayOutputStream baos = new ByteArrayOutputStream(2048);
        int n;
        while ((n = is.read(buffer)) != -1) {
            baos.write(buffer, 0, n);
        }
        return baos.toByteArray();
    }

    
Returns the encoded form of this certification path, using the
default encoding.

Throws:
Returns:the encoded bytes
/**
     * Returns the encoded form of this certification path, using the
     * default encoding.
     *
     * @return the encoded bytes
     * @exception CertificateEncodingException if an encoding error occurs
     */
    @Override
    public byte[] getEncoded() throws CertificateEncodingException {
        // @@@ Should cache the encoded form
        return encodePKIPATH();
    }

    
Encode the CertPath using PKIPATH format.

Throws:
Returns:a byte array containing the binary encoding of the PkiPath object
/**
     * Encode the CertPath using PKIPATH format.
     *
     * @return a byte array containing the binary encoding of the PkiPath object
     * @exception CertificateEncodingException if an exception occurs
     */
    private byte[] encodePKIPATH() throws CertificateEncodingException {

        ListIterator<X509Certificate> li = certs.listIterator(certs.size());
        try {
            DerOutputStream bytes = new DerOutputStream();
            // encode certs in reverse order (trust anchor to target)
            // according to PkiPath format
            while (li.hasPrevious()) {
                X509Certificate cert = li.previous();
                // check for duplicate cert
                if (certs.lastIndexOf(cert) != certs.indexOf(cert)) {
                    throw new CertificateEncodingException
                        ("Duplicate Certificate");
                }
                // get encoded certificates
                byte[] encoded = cert.getEncoded();
                bytes.write(encoded);
            }

            // Wrap the data in a SEQUENCE
            DerOutputStream derout = new DerOutputStream();
            derout.write(DerValue.tag_SequenceOf, bytes);
            return derout.toByteArray();

        } catch (IOException ioe) {
           throw new CertificateEncodingException("IOException encoding " +
                   "PkiPath data: " + ioe, ioe);
        }
    }

    
Encode the CertPath using PKCS#7 format.

Throws:
Returns:a byte array containing the binary encoding of the PKCS#7 object
/**
     * Encode the CertPath using PKCS#7 format.
     *
     * @return a byte array containing the binary encoding of the PKCS#7 object
     * @exception CertificateEncodingException if an exception occurs
     */
    private byte[] encodePKCS7() throws CertificateEncodingException {
        PKCS7 p7 = new PKCS7(new AlgorithmId[0],
                             new ContentInfo(ContentInfo.DATA_OID, null),
                             certs.toArray(new X509Certificate[certs.size()]),
                             new SignerInfo[0]);
        DerOutputStream derout = new DerOutputStream();
        try {
            p7.encodeSignedData(derout);
        } catch (IOException ioe) {
            throw new CertificateEncodingException(ioe.getMessage());
        }
        return derout.toByteArray();
    }

    
Returns the encoded form of this certification path, using the
specified encoding.

Params:
  • encoding – the name of the encoding to use
Throws:
Returns:the encoded bytes
/**
     * Returns the encoded form of this certification path, using the
     * specified encoding.
     *
     * @param encoding the name of the encoding to use
     * @return the encoded bytes
     * @exception CertificateEncodingException if an encoding error occurs or
     *   the encoding requested is not supported
     */
    @Override
    public byte[] getEncoded(String encoding)
            throws CertificateEncodingException {
        switch (encoding) {
            case PKIPATH_ENCODING:
                return encodePKIPATH();
            case PKCS7_ENCODING:
                return encodePKCS7();
            default:
                throw new CertificateEncodingException("unsupported encoding");
        }
    }

    
Returns the encodings supported by this certification path, with the
default encoding first.

Returns:an Iterator over the names of the supported
        encodings (as Strings)
/**
     * Returns the encodings supported by this certification path, with the
     * default encoding first.
     *
     * @return an <code>Iterator</code> over the names of the supported
     *         encodings (as Strings)
     */
    public static Iterator<String> getEncodingsStatic() {
        return encodingList.iterator();
    }

    
Returns an iteration of the encodings supported by this certification
path, with the default encoding first.


Attempts to modify the returned Iterator via its
remove method result in an
UnsupportedOperationException.

Returns:an Iterator over the names of the supported
        encodings (as Strings)
/**
     * Returns an iteration of the encodings supported by this certification
     * path, 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
     *         encodings (as Strings)
     */
    @Override
    public Iterator<String> getEncodings() {
        return getEncodingsStatic();
    }

    
Returns the list of certificates in this certification path.
The List returned must be immutable and thread-safe.

Returns:an immutable List of X509Certificates
        (may be empty, but not null)
/**
     * Returns the list of certificates in this certification path.
     * The <code>List</code> returned must be immutable and thread-safe.
     *
     * @return an immutable <code>List</code> of <code>X509Certificate</code>s
     *         (may be empty, but not null)
     */
    @Override
    public List<X509Certificate> getCertificates() {
        return certs;
    }
}