/*

 * Copyright (c) 2000, 2014, 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.x509;

import java.io.IOException;

import java.io.OutputStream;

import java.util.ArrayList;

import java.util.Enumeration;

import java.util.HashMap;

import java.util.List;

import java.util.Map;

import java.util.Vector;

import sun.security.util.DerValue;

import sun.security.util.DerOutputStream;

import sun.security.util.ObjectIdentifier;

/**

 * This class defines the Extended Key Usage Extension, which

 * indicates one or more purposes for which the certified public key

 * may be used, in addition to or in place of the basic purposes

 * indicated in the key usage extension field.  This field is defined

 * as follows:<p>

 *

 * id-ce-extKeyUsage OBJECT IDENTIFIER ::= {id-ce 37}<p>

 *

 * ExtKeyUsageSyntax ::= SEQUENCE SIZE (1..MAX) OF KeyPurposeId<p>

 *

 * KeyPurposeId ::= OBJECT IDENTIFIER<p>

 *

 * Key purposes may be defined by any organization with a need. Object

 * identifiers used to identify key purposes shall be assigned in

 * accordance with IANA or ITU-T Rec. X.660 | ISO/IEC/ITU 9834-1.<p>

 *

 * This extension may, at the option of the certificate issuer, be

 * either critical or non-critical.<p>

 *

 * If the extension is flagged critical, then the certificate MUST be

 * used only for one of the purposes indicated.<p>

 *

 * If the extension is flagged non-critical, then it indicates the

 * intended purpose or purposes of the key, and may be used in finding

 * the correct key/certificate of an entity that has multiple

 * keys/certificates. It is an advisory field and does not imply that

 * usage of the key is restricted by the certification authority to

 * the purpose indicated. Certificate using applications may

 * nevertheless require that a particular purpose be indicated in

 * order for the certificate to be acceptable to that application.<p>

 * If a certificate contains both a critical key usage field and a

 * critical extended key usage field, then both fields MUST be

 * processed independently and the certificate MUST only be used for a

 * purpose consistent with both fields.  If there is no purpose

 * consistent with both fields, then the certificate MUST NOT be used

 * for any purpose.<p>

 *

 * @since       1.4

 */

public class ExtendedKeyUsageExtension extends Extension

implements CertAttrSet<String> {

    /**

     * Identifier for this attribute, to be used with the

     * get, set, delete methods of Certificate, x509 type.

     */

    public static final String IDENT = "x509.info.extensions.ExtendedKeyUsage";

    /**

     * Attribute names.

     */

    public static final String NAME = "ExtendedKeyUsage";

    public static final String USAGES = "usages";

    // OID defined in RFC 5280 Sections 4.2.1.12

    // more from http://www.alvestrand.no/objectid/1.3.6.1.5.5.7.3.html

    private static final Map <ObjectIdentifier, String> map =

            new HashMap <ObjectIdentifier, String> ();

    private static final int[] anyExtendedKeyUsageOidData = {2, 5, 29, 37, 0};

    private static final int[] serverAuthOidData = {1, 3, 6, 1, 5, 5, 7, 3, 1};

    private static final int[] clientAuthOidData = {1, 3, 6, 1, 5, 5, 7, 3, 2};

    private static final int[] codeSigningOidData = {1, 3, 6, 1, 5, 5, 7, 3, 3};

    private static final int[] emailProtectionOidData = {1, 3, 6, 1, 5, 5, 7, 3, 4};

    private static final int[] ipsecEndSystemOidData = {1, 3, 6, 1, 5, 5, 7, 3, 5};

    private static final int[] ipsecTunnelOidData = {1, 3, 6, 1, 5, 5, 7, 3, 6};

    private static final int[] ipsecUserOidData = {1, 3, 6, 1, 5, 5, 7, 3, 7};

    private static final int[] timeStampingOidData = {1, 3, 6, 1, 5, 5, 7, 3, 8};

    private static final int[] OCSPSigningOidData = {1, 3, 6, 1, 5, 5, 7, 3, 9};

    static {

        map.put(ObjectIdentifier.newInternal(anyExtendedKeyUsageOidData), "anyExtendedKeyUsage");

        map.put(ObjectIdentifier.newInternal(serverAuthOidData), "serverAuth");

        map.put(ObjectIdentifier.newInternal(clientAuthOidData), "clientAuth");

        map.put(ObjectIdentifier.newInternal(codeSigningOidData), "codeSigning");

        map.put(ObjectIdentifier.newInternal(emailProtectionOidData), "emailProtection");

        map.put(ObjectIdentifier.newInternal(ipsecEndSystemOidData), "ipsecEndSystem");

        map.put(ObjectIdentifier.newInternal(ipsecTunnelOidData), "ipsecTunnel");

        map.put(ObjectIdentifier.newInternal(ipsecUserOidData), "ipsecUser");

        map.put(ObjectIdentifier.newInternal(timeStampingOidData), "timeStamping");

        map.put(ObjectIdentifier.newInternal(OCSPSigningOidData), "OCSPSigning");

    };

    /**

     * Vector of KeyUsages for this object.

     */

    private Vector<ObjectIdentifier> keyUsages;

    // Encode this extension value.

    private void encodeThis() throws IOException {

        if (keyUsages == null || keyUsages.isEmpty()) {

            this.extensionValue = null;

            return;

        }

        DerOutputStream os = new DerOutputStream();

        DerOutputStream tmp = new DerOutputStream();

        for (int i = 0; i < keyUsages.size(); i++) {

            tmp.putOID(keyUsages.elementAt(i));

        }

        os.write(DerValue.tag_Sequence, tmp);

        this.extensionValue = os.toByteArray();

    }

    /**

     * Create a ExtendedKeyUsageExtension object from

     * a Vector of Key Usages; the criticality is set to false.

     *

     * @param keyUsages the Vector of KeyUsages (ObjectIdentifiers)

     */

    public ExtendedKeyUsageExtension(Vector<ObjectIdentifier> keyUsages)

    throws IOException {

        this(Boolean.FALSE, keyUsages);

    }

    /**

     * Create a ExtendedKeyUsageExtension object from

     * a Vector of KeyUsages with specified criticality.

     *

     * @param critical true if the extension is to be treated as critical.

     * @param keyUsages the Vector of KeyUsages (ObjectIdentifiers)

     */

    public ExtendedKeyUsageExtension(Boolean critical, Vector<ObjectIdentifier> keyUsages)

    throws IOException {

        this.keyUsages = keyUsages;

        this.extensionId = PKIXExtensions.ExtendedKeyUsage_Id;

        this.critical = critical.booleanValue();

        encodeThis();

    }

    /**

     * Create the extension from its DER encoded value and criticality.

     *

     * @param critical true if the extension is to be treated as critical.

     * @param value an array of DER encoded bytes of the actual value.

     * @exception ClassCastException if value is not an array of bytes

     * @exception IOException on error.

     */

    public ExtendedKeyUsageExtension(Boolean critical, Object value)

    throws IOException {

        this.extensionId = PKIXExtensions.ExtendedKeyUsage_Id;

        this.critical = critical.booleanValue();

        this.extensionValue = (byte[]) value;

        DerValue val = new DerValue(this.extensionValue);

        if (val.tag != DerValue.tag_Sequence) {

            throw new IOException("Invalid encoding for " +

                                   "ExtendedKeyUsageExtension.");

        }

        keyUsages = new Vector<ObjectIdentifier>();

        while (val.data.available() != 0) {

            DerValue seq = val.data.getDerValue();

            ObjectIdentifier usage = seq.getOID();

            keyUsages.addElement(usage);

        }

    }

    /**

     * Return the extension as user readable string.

     */

    public String toString() {

        if (keyUsages == null) return "";

        String usage = "  ";

        boolean first = true;

        for (ObjectIdentifier oid: keyUsages) {

            if(!first) {

                usage += "\n  ";

            }

            String result = map.get(oid);

            if (result != null) {

                usage += result;

            } else {

                usage += oid.toString();

            }

            first = false;

        }

        return super.toString() + "ExtendedKeyUsages [\n"

               + usage + "\n]\n";

    }

    /**

     * Write the extension to the DerOutputStream.

     *

     * @param out the DerOutputStream to write the extension to.

     * @exception IOException on encoding errors.

     */

    public void encode(OutputStream out) throws IOException {

        DerOutputStream tmp = new DerOutputStream();

        if (extensionValue == null) {

          extensionId = PKIXExtensions.ExtendedKeyUsage_Id;

          critical = false;

          encodeThis();

        }

        super.encode(tmp);

        out.write(tmp.toByteArray());

    }

    /**

     * Set the attribute value.

     */

    @SuppressWarnings("unchecked") // Checked with instanceof

    public void set(String name, Object obj) throws IOException {

        if (name.equalsIgnoreCase(USAGES)) {

            if (!(obj instanceof Vector)) {

                throw new IOException("Attribute value should be of type Vector.");

            }

            this.keyUsages = (Vector<ObjectIdentifier>)obj;

        } else {

          throw new IOException("Attribute name [" + name +

                                "] not recognized by " +

                                "CertAttrSet:ExtendedKeyUsageExtension.");

        }

        encodeThis();

    }

    /**

     * Get the attribute value.

     */

    public Vector<ObjectIdentifier> get(String name) throws IOException {

        if (name.equalsIgnoreCase(USAGES)) {

            //XXXX May want to consider cloning this

            return keyUsages;

        } else {

          throw new IOException("Attribute name [" + name +

                                "] not recognized by " +

                                "CertAttrSet:ExtendedKeyUsageExtension.");

        }

    }

    /**

     * Delete the attribute value.

     */

    public void delete(String name) throws IOException {

        if (name.equalsIgnoreCase(USAGES)) {

            keyUsages = null;

        } else {

          throw new IOException("Attribute name [" + name +

                                "] not recognized by " +

                                "CertAttrSet:ExtendedKeyUsageExtension.");

        }

        encodeThis();

    }

    /**

     * Return an enumeration of names of attributes existing within this

     * attribute.

     */

    public Enumeration<String> getElements() {

        AttributeNameEnumeration elements = new AttributeNameEnumeration();

        elements.addElement(USAGES);

        return (elements.elements());

    }

    /**

     * Return the name of this attribute.

     */

    public String getName() {

        return (NAME);

    }

    public List<String> getExtendedKeyUsage() {

        List<String> al = new ArrayList<String>(keyUsages.size());

        for (ObjectIdentifier oid : keyUsages) {

            al.add(oid.toString());

        }

        return al;

    }

}