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package sun.security.validator;
import java.util.*;
import java.security.*;
import java.security.cert.*;
import javax.security.auth.x500.X500Principal;
import sun.security.action.GetBooleanAction;
import sun.security.provider.certpath.AlgorithmChecker;
import sun.security.provider.certpath.PKIXTimestampParameters;
/**
* Validator implementation built on the PKIX CertPath API. This
* implementation will be emphasized going forward.
* <p>
* Note that the validate() implementation tries to use a PKIX validator
* if that appears possible and a PKIX builder otherwise. This increases
* performance and currently also leads to better exception messages
* in case of failures.
* <p>
* {@code PKIXValidator} objects are immutable once they have been created.
* Please DO NOT add methods that can change the state of an instance once
* it has been created.
*
* @author Andreas Sterbenz
*/
public final class PKIXValidator extends Validator {
/**
* Flag indicating whether to enable revocation check for the PKIX trust
* manager. Typically, this will only work if the PKIX implementation
* supports CRL distribution points as we do not manually setup CertStores.
*/
private static final boolean checkTLSRevocation =
AccessController.doPrivileged
(new GetBooleanAction("com.sun.net.ssl.checkRevocation"));
private final Set<X509Certificate> trustedCerts;
private final PKIXBuilderParameters parameterTemplate;
private int certPathLength = -1;
// needed only for the validator
private final Map<X500Principal, List<PublicKey>> trustedSubjects;
private final CertificateFactory factory;
private final boolean plugin;
PKIXValidator(String variant, Collection<X509Certificate> trustedCerts) {
super(TYPE_PKIX, variant);
this.trustedCerts = (trustedCerts instanceof Set) ?
(Set<X509Certificate>)trustedCerts :
new HashSet<X509Certificate>(trustedCerts);
Set<TrustAnchor> trustAnchors = new HashSet<>();
for (X509Certificate cert : trustedCerts) {
trustAnchors.add(new TrustAnchor(cert, null));
}
try {
parameterTemplate = new PKIXBuilderParameters(trustAnchors, null);
factory = CertificateFactory.getInstance("X.509");
} catch (InvalidAlgorithmParameterException e) {
throw new RuntimeException("Unexpected error: " + e.toString(), e);
} catch (CertificateException e) {
throw new RuntimeException("Internal error", e);
}
setDefaultParameters(variant);
plugin = variant.equals(VAR_PLUGIN_CODE_SIGNING);
trustedSubjects = setTrustedSubjects();
}
PKIXValidator(String variant, PKIXBuilderParameters params) {
super(TYPE_PKIX, variant);
trustedCerts = new HashSet<X509Certificate>();
for (TrustAnchor anchor : params.getTrustAnchors()) {
X509Certificate cert = anchor.getTrustedCert();
if (cert != null) {
trustedCerts.add(cert);
}
}
parameterTemplate = params;
try {
factory = CertificateFactory.getInstance("X.509");
} catch (CertificateException e) {
throw new RuntimeException("Internal error", e);
}
plugin = variant.equals(VAR_PLUGIN_CODE_SIGNING);
trustedSubjects = setTrustedSubjects();
}
/**
* Populate the trustedSubjects Map using the DN and public keys from
* the list of trusted certificates
*
* @return Map containing each subject DN and one or more public keys
* tied to those DNs.
*/
private Map<X500Principal, List<PublicKey>> setTrustedSubjects() {
Map<X500Principal, List<PublicKey>> subjectMap = new HashMap<>();
for (X509Certificate cert : trustedCerts) {
X500Principal dn = cert.getSubjectX500Principal();
List<PublicKey> keys;
if (subjectMap.containsKey(dn)) {
keys = subjectMap.get(dn);
} else {
keys = new ArrayList<PublicKey>();
subjectMap.put(dn, keys);
}
keys.add(cert.getPublicKey());
}
return subjectMap;
}
public Collection<X509Certificate> getTrustedCertificates() {
return trustedCerts;
}
/**
* Returns the length of the last certification path that is validated by
* CertPathValidator. This is intended primarily as a callback mechanism
* for PKIXCertPathCheckers to determine the length of the certification
* path that is being validated. It is necessary since engineValidate()
* may modify the length of the path.
*
* @return the length of the last certification path passed to
* CertPathValidator.validate, or -1 if it has not been invoked yet
*/
public int getCertPathLength() { // mutable, should be private
return certPathLength;
}
/**
* Set J2SE global default PKIX parameters. Currently, hardcoded to disable
* revocation checking. In the future, this should be configurable.
*/
private void setDefaultParameters(String variant) {
if ((variant == Validator.VAR_TLS_SERVER) ||
(variant == Validator.VAR_TLS_CLIENT)) {
parameterTemplate.setRevocationEnabled(checkTLSRevocation);
} else {
parameterTemplate.setRevocationEnabled(false);
}
}
/**
* Return the PKIX parameters used by this instance. An application may
* modify the parameters but must make sure not to perform any concurrent
* validations.
*/
public PKIXBuilderParameters getParameters() { // mutable, should be private
return parameterTemplate;
}
@Override
X509Certificate[] engineValidate(X509Certificate[] chain,
Collection<X509Certificate> otherCerts,
List<byte[]> responseList,
AlgorithmConstraints constraints,
Object parameter) throws CertificateException {
if ((chain == null) || (chain.length == 0)) {
throw new CertificateException
("null or zero-length certificate chain");
}
// Check if 'parameter' affects 'pkixParameters'
PKIXBuilderParameters pkixParameters = null;
if (parameter instanceof Timestamp && plugin) {
try {
pkixParameters = new PKIXTimestampParameters(
(PKIXBuilderParameters) parameterTemplate.clone(),
(Timestamp) parameter);
} catch (InvalidAlgorithmParameterException e) {
// ignore exception
}
} else {
pkixParameters = (PKIXBuilderParameters) parameterTemplate.clone();
}
// add new algorithm constraints checker
if (constraints != null) {
pkixParameters.addCertPathChecker(new AlgorithmChecker(constraints));
}
// attach it to the PKIXBuilderParameters.
if (!responseList.isEmpty()) {
addResponses(pkixParameters, chain, responseList);
}
// check that chain is in correct order and check if chain contains
// trust anchor
X500Principal prevIssuer = null;
for (int i = 0; i < chain.length; i++) {
X509Certificate cert = chain[i];
X500Principal dn = cert.getSubjectX500Principal();
if (i != 0 && !dn.equals(prevIssuer)) {
// chain is not ordered correctly, call builder instead
return doBuild(chain, otherCerts, pkixParameters);
}
// Check if chain[i] is already trusted. It may be inside
// trustedCerts, or has the same dn and public key as a cert
// inside trustedCerts. The latter happens when a CA has
// updated its cert with a stronger signature algorithm in JRE
// but the weak one is still in circulation.
if (trustedCerts.contains(cert) || // trusted cert
(trustedSubjects.containsKey(dn) && // replacing ...
trustedSubjects.get(dn).contains( // ... weak cert
cert.getPublicKey()))) {
if (i == 0) {
return new X509Certificate[] {chain[0]};
}
// Remove and call validator on partial chain [0 .. i-1]
X509Certificate[] newChain = new X509Certificate[i];
System.arraycopy(chain, 0, newChain, 0, i);
return doValidate(newChain, pkixParameters);
}
prevIssuer = cert.getIssuerX500Principal();
}
// apparently issued by trust anchor?
X509Certificate last = chain[chain.length - 1];
X500Principal issuer = last.getIssuerX500Principal();
X500Principal subject = last.getSubjectX500Principal();
if (trustedSubjects.containsKey(issuer) &&
isSignatureValid(trustedSubjects.get(issuer), last)) {
return doValidate(chain, pkixParameters);
}
// don't fallback to builder if called from plugin/webstart
if (plugin) {
// Validate chain even if no trust anchor is found. This
// allows plugin/webstart to make sure the chain is
// otherwise valid
if (chain.length > 1) {
X509Certificate[] newChain =
new X509Certificate[chain.length-1];
System.arraycopy(chain, 0, newChain, 0, newChain.length);
// temporarily set last cert as sole trust anchor
try {
pkixParameters.setTrustAnchors
(Collections.singleton(new TrustAnchor
(chain[chain.length-1], null)));
} catch (InvalidAlgorithmParameterException iape) {
// should never occur, but ...
throw new CertificateException(iape);
}
doValidate(newChain, pkixParameters);
}
// if the rest of the chain is valid, throw exception
// indicating no trust anchor was found
throw new ValidatorException
(ValidatorException.T_NO_TRUST_ANCHOR);
}
// otherwise, fall back to builder
return doBuild(chain, otherCerts, pkixParameters);
}
private boolean isSignatureValid(List<PublicKey> keys,
X509Certificate sub) {
if (plugin) {
for (PublicKey key: keys) {
try {
sub.verify(key);
return true;
} catch (Exception ex) {
continue;
}
}
return false;
}
return true; // only check if PLUGIN is set
}
private static X509Certificate[] toArray(CertPath path, TrustAnchor anchor)
throws CertificateException {
List<? extends java.security.cert.Certificate> list =
path.getCertificates();
X509Certificate[] chain = new X509Certificate[list.size() + 1];
list.toArray(chain);
X509Certificate trustedCert = anchor.getTrustedCert();
if (trustedCert == null) {
throw new ValidatorException
("TrustAnchor must be specified as certificate");
}
chain[chain.length - 1] = trustedCert;
return chain;
}
/**
* Set the check date (for debugging).
*/
private void setDate(PKIXBuilderParameters params) {
@SuppressWarnings("deprecation")
Date date = validationDate;
if (date != null) {
params.setDate(date);
}
}
private X509Certificate[] doValidate(X509Certificate[] chain,
PKIXBuilderParameters params) throws CertificateException {
try {
setDate(params);
// do the validation
CertPathValidator validator = CertPathValidator.getInstance("PKIX");
CertPath path = factory.generateCertPath(Arrays.asList(chain));
certPathLength = chain.length;
PKIXCertPathValidatorResult result =
(PKIXCertPathValidatorResult)validator.validate(path, params);
return toArray(path, result.getTrustAnchor());
} catch (GeneralSecurityException e) {
throw new ValidatorException
("PKIX path validation failed: " + e.toString(), e);
}
}
private X509Certificate[] doBuild(X509Certificate[] chain,
Collection<X509Certificate> otherCerts,
PKIXBuilderParameters params) throws CertificateException {
try {
setDate(params);
// setup target constraints
X509CertSelector selector = new X509CertSelector();
selector.setCertificate(chain[0]);
params.setTargetCertConstraints(selector);
// setup CertStores
Collection<X509Certificate> certs =
new ArrayList<X509Certificate>();
certs.addAll(Arrays.asList(chain));
if (otherCerts != null) {
certs.addAll(otherCerts);
}
CertStore store = CertStore.getInstance("Collection",
new CollectionCertStoreParameters(certs));
params.addCertStore(store);
// do the build
CertPathBuilder builder = CertPathBuilder.getInstance("PKIX");
PKIXCertPathBuilderResult result =
(PKIXCertPathBuilderResult)builder.build(params);
return toArray(result.getCertPath(), result.getTrustAnchor());
} catch (GeneralSecurityException e) {
throw new ValidatorException
("PKIX path building failed: " + e.toString(), e);
}
}
/**
* For OCSP Stapling, add responses that came in during the handshake
* into a {@code PKIXRevocationChecker} so we can evaluate them.
*
* @param pkixParams the pkixParameters object that will be used in
* path validation.
* @param chain the chain of certificates to verify
* @param responseList a {@code List} of zero or more byte arrays, each
* one being a DER-encoded OCSP response (per RFC 6960). Entries
* in the List must match the order of the certificates in the
* chain parameter.
*/
private static void addResponses(PKIXBuilderParameters pkixParams,
X509Certificate[] chain, List<byte[]> responseList) {
if (pkixParams.isRevocationEnabled()) {
try {
// Make a modifiable copy of the CertPathChecker list
PKIXRevocationChecker revChecker = null;
List<PKIXCertPathChecker> checkerList =
new ArrayList<>(pkixParams.getCertPathCheckers());
// Find the first PKIXRevocationChecker in the list
for (PKIXCertPathChecker checker : checkerList) {
if (checker instanceof PKIXRevocationChecker) {
revChecker = (PKIXRevocationChecker)checker;
break;
}
}
// If we still haven't found one, make one
if (revChecker == null) {
revChecker = (PKIXRevocationChecker)CertPathValidator.
getInstance("PKIX").getRevocationChecker();
checkerList.add(revChecker);
}
// Each response in the list should be in parallel with
// the certificate list. If there is a zero-length response
// treat it as being absent. If the user has provided their
// own PKIXRevocationChecker with pre-populated responses, do
// not overwrite them with the ones from the handshake.
Map<X509Certificate, byte[]> responseMap =
revChecker.getOcspResponses();
int limit = Integer.min(chain.length, responseList.size());
for (int idx = 0; idx < limit; idx++) {
byte[] respBytes = responseList.get(idx);
if (respBytes != null && respBytes.length > 0 &&
!responseMap.containsKey(chain[idx])) {
responseMap.put(chain[idx], respBytes);
}
}
// Add the responses and push it all back into the
// PKIXBuilderParameters
revChecker.setOcspResponses(responseMap);
pkixParams.setCertPathCheckers(checkerList);
} catch (NoSuchAlgorithmException exc) {
// This should not occur, but if it does happen then
// stapled OCSP responses won't be part of revocation checking.
// Clients can still fall back to other means of revocation
// checking.
}
}
}
}