/*
* 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
* or visit www.oracle.com if you need additional information or have any
* questions.
*/
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;
}
}