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public final class

SimpleValidator

extends Validator
/*
 * Copyright (c) 2002, 2009, 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.validator;

import java.io.IOException;
import java.util.*;

import java.security.*;
import java.security.cert.*;

import javax.security.auth.x500.X500Principal;

import sun.security.x509.X509CertImpl;
import sun.security.x509.NetscapeCertTypeExtension;
import sun.security.util.DerValue;
import sun.security.util.DerInputStream;
import sun.security.util.DerOutputStream;
import sun.security.util.ObjectIdentifier;

import sun.security.provider.certpath.AlgorithmChecker;

/**
 * A simple validator implementation. It is based on code from the JSSE
 * X509TrustManagerImpl. This implementation is designed for compatibility with
 * deployed certificates and previous J2SE versions. It will never support
 * more advanced features and will be deemphasized in favor of the PKIX
 * validator going forward.
 *
 * @author Andreas Sterbenz
 */

public final class SimpleValidator extends Validator {

   
// Constants for the OIDs we need

   
final static String OID_BASIC_CONSTRAINTS = "2.5.29.19";

   
final static String OID_NETSCAPE_CERT_TYPE = "2.16.840.1.113730.1.1";

   
final static String OID_KEY_USAGE = "2.5.29.15";

   
final static String OID_EXTENDED_KEY_USAGE = "2.5.29.37";

   
final static String OID_EKU_ANY_USAGE = "2.5.29.37.0";

   
final static ObjectIdentifier OBJID_NETSCAPE_CERT_TYPE =
       
NetscapeCertTypeExtension.NetscapeCertType_Id;

   
private final static String NSCT_SSL_CA =
                               
NetscapeCertTypeExtension.SSL_CA;

   
private final static String NSCT_CODE_SIGNING_CA =
                               
NetscapeCertTypeExtension.OBJECT_SIGNING_CA;

   
/**
     * The trusted certificates as:
     * Map (X500Principal)subject of trusted cert -> List of X509Certificate
     * The list is used because there may be multiple certificates
     * with an identical subject DN.
     */

   
private Map<X500Principal, List<X509Certificate>> trustedX500Principals;

   
/**
     * Set of the trusted certificates. Present only for
     * getTrustedCertificates().
     */

   
private Collection<X509Certificate> trustedCerts;

   
SimpleValidator(String variant, Collection<X509Certificate> trustedCerts) {
       
super(TYPE_SIMPLE, variant);
       
this.trustedCerts = trustedCerts;
        trustedX500Principals
=
                       
new HashMap<X500Principal, List<X509Certificate>>();
       
for (X509Certificate cert : trustedCerts) {
            X500Principal principal
= cert.getSubjectX500Principal();
           
List<X509Certificate> list = trustedX500Principals.get(principal);
           
if (list == null) {
               
// this actually should be a set, but duplicate entries
               
// are not a problem and we can avoid the Set overhead
                list
= new ArrayList<X509Certificate>(2);
                trustedX500Principals
.put(principal, list);
           
}
            list
.add(cert);
       
}
   
}

   
public Collection<X509Certificate> getTrustedCertificates() {
       
return trustedCerts;
   
}

   
/**
     * Perform simple validation of chain. The arguments otherCerts and
     * parameter are ignored.
     */

    X509Certificate
[] engineValidate(X509Certificate[] chain,
           
Collection<X509Certificate> otherCerts, Object parameter)
           
throws CertificateException {
       
if ((chain == null) || (chain.length == 0)) {
           
throw new CertificateException
               
("null or zero-length certificate chain");
       
}

       
// make sure chain includes a trusted cert
        chain
= buildTrustedChain(chain);

       
Date date = validationDate;
       
if (date == null) {
            date
= new Date();
       
}
       
// verify top down, starting at the certificate issued by
       
// the trust anchor
       
for (int i = chain.length - 2; i >= 0; i--) {
            X509Certificate issuerCert
= chain[i + 1];
            X509Certificate cert
= chain[i];

           
// check certificate algorithm
           
try {
               
AlgorithmChecker.check(cert);
           
} catch (CertPathValidatorException cpve) {
               
throw new ValidatorException
                       
(ValidatorException.T_ALGORITHM_DISABLED, cert, cpve);
           
}

           
// no validity check for code signing certs
           
if ((variant.equals(VAR_CODE_SIGNING) == false)
                       
&& (variant.equals(VAR_JCE_SIGNING) == false)) {
                cert
.checkValidity(date);
           
}

           
// check name chaining
           
if (cert.getIssuerX500Principal().equals(
                        issuerCert
.getSubjectX500Principal()) == false) {
               
throw new ValidatorException
                       
(ValidatorException.T_NAME_CHAINING, cert);
           
}

           
// check signature
           
try {
                cert
.verify(issuerCert.getPublicKey());
           
} catch (GeneralSecurityException e) {
               
throw new ValidatorException
                       
(ValidatorException.T_SIGNATURE_ERROR, cert, e);
           
}

           
// check extensions for CA certs
           
if (i != 0) {
                checkExtensions
(cert, i);
           
}
       
}

       
return chain;
   
}

   
private void checkExtensions(X509Certificate cert, int index)
           
throws CertificateException {
       
Set<String> critSet = cert.getCriticalExtensionOIDs();
       
if (critSet == null) {
            critSet
= Collections.<String>emptySet();
       
}

       
// Check the basic constraints extension
        checkBasicConstraints
(cert, critSet, index);

       
// Check the key usage and extended key usage extensions
        checkKeyUsage
(cert, critSet);

       
// check Netscape certificate type extension
        checkNetscapeCertType
(cert, critSet);

       
if (!critSet.isEmpty()) {
           
throw new ValidatorException
               
("Certificate contains unknown critical extensions: " + critSet,
               
ValidatorException.T_CA_EXTENSIONS, cert);
       
}
   
}

   
private void checkNetscapeCertType(X509Certificate cert,
           
Set<String> critSet) throws CertificateException {
       
if (variant.equals(VAR_GENERIC)) {
           
// nothing
       
} else if (variant.equals(VAR_TLS_CLIENT)
               
|| variant.equals(VAR_TLS_SERVER)) {
           
if (getNetscapeCertTypeBit(cert, NSCT_SSL_CA) == false) {
               
throw new ValidatorException
                       
("Invalid Netscape CertType extension for SSL CA "
                       
+ "certificate",
                       
ValidatorException.T_CA_EXTENSIONS, cert);
           
}
            critSet
.remove(OID_NETSCAPE_CERT_TYPE);
       
} else if (variant.equals(VAR_CODE_SIGNING)
               
|| variant.equals(VAR_JCE_SIGNING)) {
           
if (getNetscapeCertTypeBit(cert, NSCT_CODE_SIGNING_CA) == false) {
               
throw new ValidatorException
                       
("Invalid Netscape CertType extension for code "
                       
+ "signing CA certificate",
                       
ValidatorException.T_CA_EXTENSIONS, cert);
           
}
            critSet
.remove(OID_NETSCAPE_CERT_TYPE);
       
} else {
           
throw new CertificateException("Unknown variant " + variant);
       
}
   
}

   
/**
     * Get the value of the specified bit in the Netscape certificate type
     * extension. If the extension is not present at all, we return true.
     */

   
static boolean getNetscapeCertTypeBit(X509Certificate cert, String type) {
       
try {
           
NetscapeCertTypeExtension ext;
           
if (cert instanceof X509CertImpl) {
                X509CertImpl certImpl
= (X509CertImpl)cert;
               
ObjectIdentifier oid = OBJID_NETSCAPE_CERT_TYPE;
                ext
= (NetscapeCertTypeExtension)certImpl.getExtension(oid);
               
if (ext == null) {
                   
return true;
               
}
           
} else {
               
byte[] extVal = cert.getExtensionValue(OID_NETSCAPE_CERT_TYPE);
               
if (extVal == null) {
                   
return true;
               
}
               
DerInputStream in = new DerInputStream(extVal);
               
byte[] encoded = in.getOctetString();
                encoded
= new DerValue(encoded).getUnalignedBitString()
                                                               
.toByteArray();
                ext
= new NetscapeCertTypeExtension(encoded);
           
}
           
Boolean val = (Boolean)ext.get(type);
           
return val.booleanValue();
       
} catch (IOException e) {
           
return false;
       
}
   
}

   
private void checkBasicConstraints(X509Certificate cert,
           
Set<String> critSet, int index) throws CertificateException {

        critSet
.remove(OID_BASIC_CONSTRAINTS);
       
int constraints = cert.getBasicConstraints();
       
// reject, if extension missing or not a CA (constraints == -1)
       
if (constraints < 0) {
           
throw new ValidatorException("End user tried to act as a CA",
               
ValidatorException.T_CA_EXTENSIONS, cert);
       
}
       
if (index - 1 > constraints) {
           
throw new ValidatorException("Violated path length constraints",
               
ValidatorException.T_CA_EXTENSIONS, cert);
       
}
   
}

   
/*
     * Verify the key usage and extended key usage for intermediate
     * certificates.
     */

   
private void checkKeyUsage(X509Certificate cert, Set<String> critSet)
           
throws CertificateException {

        critSet
.remove(OID_KEY_USAGE);
       
// EKU irrelevant in CA certificates
        critSet
.remove(OID_EXTENDED_KEY_USAGE);

       
// check key usage extension
       
boolean[] keyUsageInfo = cert.getKeyUsage();
       
if (keyUsageInfo != null) {
           
// keyUsageInfo[5] is for keyCertSign.
           
if ((keyUsageInfo.length < 6) || (keyUsageInfo[5] == false)) {
               
throw new ValidatorException
                       
("Wrong key usage: expected keyCertSign",
                       
ValidatorException.T_CA_EXTENSIONS, cert);
           
}
       
}
   
}

   
/**
     * Build a trusted certificate chain. This method always returns a chain
     * with a trust anchor as the final cert in the chain. If no trust anchor
     * could be found, a CertificateException is thrown.
     */

   
private X509Certificate[] buildTrustedChain(X509Certificate[] chain)
           
throws CertificateException {
       
List<X509Certificate> c = new ArrayList<X509Certificate>(chain.length);
       
// scan chain starting at EE cert
       
// if a trusted certificate is found, append it and return
       
for (int i = 0; i < chain.length; i++) {
            X509Certificate cert
= chain[i];
            X509Certificate trustedCert
= getTrustedCertificate(cert);
           
if (trustedCert != null) {
                c
.add(trustedCert);
               
return c.toArray(CHAIN0);
           
}
            c
.add(cert);
       
}
       
// check if we can append a trusted cert
        X509Certificate cert
= chain[chain.length - 1];
        X500Principal subject
= cert.getSubjectX500Principal();
        X500Principal issuer
= cert.getIssuerX500Principal();
       
if (subject.equals(issuer) == false) {
           
List<X509Certificate> list = trustedX500Principals.get(issuer);
           
if (list != null) {
                X509Certificate trustedCert
= list.iterator().next();
                c
.add(trustedCert);
               
return c.toArray(CHAIN0);
           
}
       
}
       
// no trusted cert found, error
       
throw new ValidatorException(ValidatorException.T_NO_TRUST_ANCHOR);
   
}

   
/**
     * Return a trusted certificate that matches the input certificate,
     * or null if no such certificate can be found. This method also handles
     * cases where a CA re-issues a trust anchor with the same public key and
     * same subject and issuer names but a new validity period, etc.
     */

   
private X509Certificate getTrustedCertificate(X509Certificate cert) {
       
Principal certSubjectName = cert.getSubjectX500Principal();
       
List<X509Certificate> list = trustedX500Principals.get(certSubjectName);
       
if (list == null) {
           
return null;
       
}

       
Principal certIssuerName = cert.getIssuerX500Principal();
       
PublicKey certPublicKey = cert.getPublicKey();

       
for (X509Certificate mycert : list) {
           
if (mycert.equals(cert)) {
               
return cert;
           
}
           
if (!mycert.getIssuerX500Principal().equals(certIssuerName)) {
               
continue;
           
}
           
if (!mycert.getPublicKey().equals(certPublicKey)) {
               
continue;
           
}

           
// All tests pass, this must be the one to use...
           
return mycert;
       
}
       
return null;
   
}

}