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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
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* particular file as subject to the "Classpath" exception as provided
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*
* 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).
*
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* 2 along with this work; if not, write to the Free Software Foundation,
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*
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package sun.security.provider.certpath;
import java.io.*;
import java.net.URI;
import java.security.*;
import java.security.cert.*;
import javax.security.auth.x500.X500Principal;
import java.util.*;
import sun.security.util.Debug;
import sun.security.util.DerOutputStream;
import static sun.security.x509.PKIXExtensions.*;
import sun.security.x509.*;
/**
* Class to obtain CRLs via the CRLDistributionPoints extension.
* Note that the functionality of this class must be explicitly enabled
* via a system property, see the USE_CRLDP variable below.
*
* This class uses the URICertStore class to fetch CRLs. The URICertStore
* class also implements CRL caching: see the class description for more
* information.
*
* @author Andreas Sterbenz
* @author Sean Mullan
* @since 1.4.2
*/
public class DistributionPointFetcher {
private static final Debug debug = Debug.getInstance("certpath");
private static final boolean[] ALL_REASONS =
{true, true, true, true, true, true, true, true, true};
/**
* Private instantiation only.
*/
private DistributionPointFetcher() {}
/**
* Return the X509CRLs matching this selector. The selector must be
* an X509CRLSelector with certificateChecking set.
*/
public static Collection<X509CRL> getCRLs(X509CRLSelector selector,
boolean signFlag,
PublicKey prevKey,
String provider,
List<CertStore> certStores,
boolean[] reasonsMask,
Set<TrustAnchor> trustAnchors,
Date validity)
throws CertStoreException
{
X509Certificate cert = selector.getCertificateChecking();
if (cert == null) {
return Collections.emptySet();
}
try {
X509CertImpl certImpl = X509CertImpl.toImpl(cert);
if (debug != null) {
debug.println("DistributionPointFetcher.getCRLs: Checking "
+ "CRLDPs for " + certImpl.getSubjectX500Principal());
}
CRLDistributionPointsExtension ext =
certImpl.getCRLDistributionPointsExtension();
if (ext == null) {
if (debug != null) {
debug.println("No CRLDP ext");
}
return Collections.emptySet();
}
List<DistributionPoint> points =
ext.get(CRLDistributionPointsExtension.POINTS);
Set<X509CRL> results = new HashSet<>();
for (Iterator<DistributionPoint> t = points.iterator();
t.hasNext() && !Arrays.equals(reasonsMask, ALL_REASONS); ) {
DistributionPoint point = t.next();
Collection<X509CRL> crls = getCRLs(selector, certImpl,
point, reasonsMask, signFlag, prevKey, provider,
certStores, trustAnchors, validity);
results.addAll(crls);
}
if (debug != null) {
debug.println("Returning " + results.size() + " CRLs");
}
return results;
} catch (CertificateException | IOException e) {
return Collections.emptySet();
}
}
/**
* Download CRLs from the given distribution point, verify and return them.
* See the top of the class for current limitations.
*
* @throws CertStoreException if there is an error retrieving the CRLs
* from one of the GeneralNames and no other CRLs are retrieved from
* the other GeneralNames. If more than one GeneralName throws an
* exception then the one from the last GeneralName is thrown.
*/
private static Collection<X509CRL> getCRLs(X509CRLSelector selector,
X509CertImpl certImpl, DistributionPoint point, boolean[] reasonsMask,
boolean signFlag, PublicKey prevKey, String provider,
List<CertStore> certStores, Set<TrustAnchor> trustAnchors,
Date validity) throws CertStoreException {
// check for full name
GeneralNames fullName = point.getFullName();
if (fullName == null) {
// check for relative name
RDN relativeName = point.getRelativeName();
if (relativeName == null) {
return Collections.emptySet();
}
try {
GeneralNames crlIssuers = point.getCRLIssuer();
if (crlIssuers == null) {
fullName = getFullNames
((X500Name) certImpl.getIssuerDN(), relativeName);
} else {
// should only be one CRL Issuer
if (crlIssuers.size() != 1) {
return Collections.emptySet();
} else {
fullName = getFullNames
((X500Name) crlIssuers.get(0).getName(), relativeName);
}
}
} catch (IOException ioe) {
return Collections.emptySet();
}
}
Collection<X509CRL> possibleCRLs = new ArrayList<>();
CertStoreException savedCSE = null;
for (Iterator<GeneralName> t = fullName.iterator(); t.hasNext(); ) {
try {
GeneralName name = t.next();
if (name.getType() == GeneralNameInterface.NAME_DIRECTORY) {
X500Name x500Name = (X500Name) name.getName();
possibleCRLs.addAll(
getCRLs(x500Name, certImpl.getIssuerX500Principal(),
certStores));
} else if (name.getType() == GeneralNameInterface.NAME_URI) {
URIName uriName = (URIName)name.getName();
X509CRL crl = getCRL(uriName);
if (crl != null) {
possibleCRLs.add(crl);
}
}
} catch (CertStoreException cse) {
savedCSE = cse;
}
}
// only throw CertStoreException if no CRLs are retrieved
if (possibleCRLs.isEmpty() && savedCSE != null) {
throw savedCSE;
}
Collection<X509CRL> crls = new ArrayList<>(2);
for (X509CRL crl : possibleCRLs) {
try {
// make sure issuer is not set
// we check the issuer in verifyCRLs method
selector.setIssuerNames(null);
if (selector.match(crl) && verifyCRL(certImpl, point, crl,
reasonsMask, signFlag, prevKey, provider, trustAnchors,
certStores, validity)) {
crls.add(crl);
}
} catch (IOException | CRLException e) {
// don't add the CRL
if (debug != null) {
debug.println("Exception verifying CRL: " + e.getMessage());
e.printStackTrace();
}
}
}
return crls;
}
/**
* Download CRL from given URI.
*/
private static X509CRL getCRL(URIName name) throws CertStoreException {
URI uri = name.getURI();
if (debug != null) {
debug.println("Trying to fetch CRL from DP " + uri);
}
CertStore ucs = null;
try {
ucs = URICertStore.getInstance
(new URICertStore.URICertStoreParameters(uri));
} catch (InvalidAlgorithmParameterException |
NoSuchAlgorithmException e) {
if (debug != null) {
debug.println("Can't create URICertStore: " + e.getMessage());
}
return null;
}
Collection<? extends CRL> crls = ucs.getCRLs(null);
if (crls.isEmpty()) {
return null;
} else {
return (X509CRL) crls.iterator().next();
}
}
/**
* Fetch CRLs from certStores.
*
* @throws CertStoreException if there is an error retrieving the CRLs from
* one of the CertStores and no other CRLs are retrieved from
* the other CertStores. If more than one CertStore throws an
* exception then the one from the last CertStore is thrown.
*/
private static Collection<X509CRL> getCRLs(X500Name name,
X500Principal certIssuer,
List<CertStore> certStores)
throws CertStoreException
{
if (debug != null) {
debug.println("Trying to fetch CRL from DP " + name);
}
X509CRLSelector xcs = new X509CRLSelector();
xcs.addIssuer(name.asX500Principal());
xcs.addIssuer(certIssuer);
Collection<X509CRL> crls = new ArrayList<>();
CertStoreException savedCSE = null;
for (CertStore store : certStores) {
try {
for (CRL crl : store.getCRLs(xcs)) {
crls.add((X509CRL)crl);
}
} catch (CertStoreException cse) {
if (debug != null) {
debug.println("Exception while retrieving " +
"CRLs: " + cse);
cse.printStackTrace();
}
savedCSE = new PKIX.CertStoreTypeException(store.getType(),cse);
}
}
// only throw CertStoreException if no CRLs are retrieved
if (crls.isEmpty() && savedCSE != null) {
throw savedCSE;
} else {
return crls;
}
}
/**
* Verifies a CRL for the given certificate's Distribution Point to
* ensure it is appropriate for checking the revocation status.
*
* @param certImpl the certificate whose revocation status is being checked
* @param point one of the distribution points of the certificate
* @param crl the CRL
* @param reasonsMask the interim reasons mask
* @param signFlag true if prevKey can be used to verify the CRL
* @param prevKey the public key that verifies the certificate's signature
* @param provider the Signature provider to use
* @param trustAnchors a {@code Set} of {@code TrustAnchor}s
* @param certStores a {@code List} of {@code CertStore}s to be used in
* finding certificates and CRLs
* @param validity the time for which the validity of the CRL issuer's
* certification path should be determined
* @return true if ok, false if not
*/
static boolean verifyCRL(X509CertImpl certImpl, DistributionPoint point,
X509CRL crl, boolean[] reasonsMask, boolean signFlag,
PublicKey prevKey, String provider,
Set<TrustAnchor> trustAnchors, List<CertStore> certStores,
Date validity) throws CRLException, IOException {
boolean indirectCRL = false;
X509CRLImpl crlImpl = X509CRLImpl.toImpl(crl);
IssuingDistributionPointExtension idpExt =
crlImpl.getIssuingDistributionPointExtension();
X500Name certIssuer = (X500Name) certImpl.getIssuerDN();
X500Name crlIssuer = (X500Name) crlImpl.getIssuerDN();
// if crlIssuer is set, verify that it matches the issuer of the
// CRL and the CRL contains an IDP extension with the indirectCRL
// boolean asserted. Otherwise, verify that the CRL issuer matches the
// certificate issuer.
GeneralNames pointCrlIssuers = point.getCRLIssuer();
X500Name pointCrlIssuer = null;
if (pointCrlIssuers != null) {
if (idpExt == null ||
((Boolean) idpExt.get
(IssuingDistributionPointExtension.INDIRECT_CRL)).equals
(Boolean.FALSE)) {
return false;
}
boolean match = false;
for (Iterator<GeneralName> t = pointCrlIssuers.iterator();
!match && t.hasNext(); ) {
GeneralNameInterface name = t.next().getName();
if (crlIssuer.equals(name) == true) {
pointCrlIssuer = (X500Name) name;
match = true;
}
}
if (match == false) {
return false;
}
// we accept the case that a CRL issuer provide status
// information for itself.
if (issues(certImpl, crlImpl, provider)) {
// reset the public key used to verify the CRL's signature
prevKey = certImpl.getPublicKey();
} else {
indirectCRL = true;
}
} else if (crlIssuer.equals(certIssuer) == false) {
if (debug != null) {
debug.println("crl issuer does not equal cert issuer");
}
return false;
} else {
// in case of self-issued indirect CRL issuer.
KeyIdentifier certAKID = certImpl.getAuthKeyId();
KeyIdentifier crlAKID = crlImpl.getAuthKeyId();
if (certAKID == null || crlAKID == null) {
// cannot recognize indirect CRL without AKID
// we accept the case that a CRL issuer provide status
// information for itself.
if (issues(certImpl, crlImpl, provider)) {
// reset the public key used to verify the CRL's signature
prevKey = certImpl.getPublicKey();
}
} else if (!certAKID.equals(crlAKID)) {
// we accept the case that a CRL issuer provide status
// information for itself.
if (issues(certImpl, crlImpl, provider)) {
// reset the public key used to verify the CRL's signature
prevKey = certImpl.getPublicKey();
} else {
indirectCRL = true;
}
}
}
if (!indirectCRL && !signFlag) {
// cert's key cannot be used to verify the CRL
return false;
}
if (idpExt != null) {
DistributionPointName idpPoint = (DistributionPointName)
idpExt.get(IssuingDistributionPointExtension.POINT);
if (idpPoint != null) {
GeneralNames idpNames = idpPoint.getFullName();
if (idpNames == null) {
RDN relativeName = idpPoint.getRelativeName();
if (relativeName == null) {
if (debug != null) {
debug.println("IDP must be relative or full DN");
}
return false;
}
if (debug != null) {
debug.println("IDP relativeName:" + relativeName);
}
idpNames = getFullNames(crlIssuer, relativeName);
}
// if the DP name is present in the IDP CRL extension and the
// DP field is present in the DP, then verify that one of the
// names in the IDP matches one of the names in the DP
if (point.getFullName() != null ||
point.getRelativeName() != null) {
GeneralNames pointNames = point.getFullName();
if (pointNames == null) {
RDN relativeName = point.getRelativeName();
if (relativeName == null) {
if (debug != null) {
debug.println("DP must be relative or full DN");
}
return false;
}
if (debug != null) {
debug.println("DP relativeName:" + relativeName);
}
if (indirectCRL) {
if (pointCrlIssuers.size() != 1) {
// RFC 3280: there must be only 1 CRL issuer
// name when relativeName is present
if (debug != null) {
debug.println("must only be one CRL " +
"issuer when relative name present");
}
return false;
}
pointNames = getFullNames
(pointCrlIssuer, relativeName);
} else {
pointNames = getFullNames(certIssuer, relativeName);
}
}
boolean match = false;
for (Iterator<GeneralName> i = idpNames.iterator();
!match && i.hasNext(); ) {
GeneralNameInterface idpName = i.next().getName();
if (debug != null) {
debug.println("idpName: " + idpName);
}
for (Iterator<GeneralName> p = pointNames.iterator();
!match && p.hasNext(); ) {
GeneralNameInterface pointName = p.next().getName();
if (debug != null) {
debug.println("pointName: " + pointName);
}
match = idpName.equals(pointName);
}
}
if (!match) {
if (debug != null) {
debug.println("IDP name does not match DP name");
}
return false;
}
// if the DP name is present in the IDP CRL extension and the
// DP field is absent from the DP, then verify that one of the
// names in the IDP matches one of the names in the crlIssuer
// field of the DP
} else {
// verify that one of the names in the IDP matches one of
// the names in the cRLIssuer of the cert's DP
boolean match = false;
for (Iterator<GeneralName> t = pointCrlIssuers.iterator();
!match && t.hasNext(); ) {
GeneralNameInterface crlIssuerName = t.next().getName();
for (Iterator<GeneralName> i = idpNames.iterator();
!match && i.hasNext(); ) {
GeneralNameInterface idpName = i.next().getName();
match = crlIssuerName.equals(idpName);
}
}
if (!match) {
return false;
}
}
}
// if the onlyContainsUserCerts boolean is asserted, verify that the
// cert is not a CA cert
Boolean b = (Boolean)
idpExt.get(IssuingDistributionPointExtension.ONLY_USER_CERTS);
if (b.equals(Boolean.TRUE) && certImpl.getBasicConstraints() != -1) {
if (debug != null) {
debug.println("cert must be a EE cert");
}
return false;
}
// if the onlyContainsCACerts boolean is asserted, verify that the
// cert is a CA cert
b = (Boolean)
idpExt.get(IssuingDistributionPointExtension.ONLY_CA_CERTS);
if (b.equals(Boolean.TRUE) && certImpl.getBasicConstraints() == -1) {
if (debug != null) {
debug.println("cert must be a CA cert");
}
return false;
}
// verify that the onlyContainsAttributeCerts boolean is not
// asserted
b = (Boolean) idpExt.get
(IssuingDistributionPointExtension.ONLY_ATTRIBUTE_CERTS);
if (b.equals(Boolean.TRUE)) {
if (debug != null) {
debug.println("cert must not be an AA cert");
}
return false;
}
}
// compute interim reasons mask
boolean[] interimReasonsMask = new boolean[9];
ReasonFlags reasons = null;
if (idpExt != null) {
reasons = (ReasonFlags)
idpExt.get(IssuingDistributionPointExtension.REASONS);
}
boolean[] pointReasonFlags = point.getReasonFlags();
if (reasons != null) {
if (pointReasonFlags != null) {
// set interim reasons mask to the intersection of
// reasons in the DP and onlySomeReasons in the IDP
boolean[] idpReasonFlags = reasons.getFlags();
for (int i = 0; i < idpReasonFlags.length; i++) {
if (idpReasonFlags[i] && pointReasonFlags[i]) {
interimReasonsMask[i] = true;
}
}
} else {
// set interim reasons mask to the value of
// onlySomeReasons in the IDP (and clone it since we may
// modify it)
interimReasonsMask = reasons.getFlags().clone();
}
} else if (idpExt == null || reasons == null) {
if (pointReasonFlags != null) {
// set interim reasons mask to the value of DP reasons
interimReasonsMask = pointReasonFlags.clone();
} else {
// set interim reasons mask to the special value all-reasons
interimReasonsMask = new boolean[9];
Arrays.fill(interimReasonsMask, true);
}
}
// verify that interim reasons mask includes one or more reasons
// not included in the reasons mask
boolean oneOrMore = false;
for (int i = 0; i < interimReasonsMask.length && !oneOrMore; i++) {
if (!reasonsMask[i] && interimReasonsMask[i]) {
oneOrMore = true;
}
}
if (!oneOrMore) {
return false;
}
// Obtain and validate the certification path for the complete
// CRL issuer (if indirect CRL). If a key usage extension is present
// in the CRL issuer's certificate, verify that the cRLSign bit is set.
if (indirectCRL) {
X509CertSelector certSel = new X509CertSelector();
certSel.setSubject(crlIssuer.asX500Principal());
boolean[] crlSign = {false,false,false,false,false,false,true};
certSel.setKeyUsage(crlSign);
// Currently by default, forward builder does not enable
// subject/authority key identifier identifying for target
// certificate, instead, it only compares the CRL issuer and
// the target certificate subject. If the certificate of the
// delegated CRL issuer is a self-issued certificate, the
// builder is unable to find the proper CRL issuer by issuer
// name only, there is a potential dead loop on finding the
// proper issuer. It is of great help to narrow the target
// scope down to aware of authority key identifiers in the
// selector, for the purposes of breaking the dead loop.
AuthorityKeyIdentifierExtension akidext =
crlImpl.getAuthKeyIdExtension();
if (akidext != null) {
KeyIdentifier akid = (KeyIdentifier)akidext.get(
AuthorityKeyIdentifierExtension.KEY_ID);
if (akid != null) {
DerOutputStream derout = new DerOutputStream();
derout.putOctetString(akid.getIdentifier());
certSel.setSubjectKeyIdentifier(derout.toByteArray());
}
SerialNumber asn = (SerialNumber)akidext.get(
AuthorityKeyIdentifierExtension.SERIAL_NUMBER);
if (asn != null) {
certSel.setSerialNumber(asn.getNumber());
}
// the subject criterion will be set by builder automatically.
}
// by far, we have validated the previous certificate, we can
// trust it during validating the CRL issuer.
// Except the performance improvement, another benefit is to break
// the dead loop while looking for the issuer back and forth
// between the delegated self-issued certificate and its issuer.
Set<TrustAnchor> newTrustAnchors = new HashSet<>(trustAnchors);
if (prevKey != null) {
// Add the previous certificate as a trust anchor.
X500Principal principal = certImpl.getIssuerX500Principal();
TrustAnchor temporary =
new TrustAnchor(principal, prevKey, null);
newTrustAnchors.add(temporary);
}
PKIXBuilderParameters params = null;
try {
params = new PKIXBuilderParameters(newTrustAnchors, certSel);
} catch (InvalidAlgorithmParameterException iape) {
throw new CRLException(iape);
}
params.setCertStores(certStores);
params.setSigProvider(provider);
params.setDate(validity);
try {
CertPathBuilder builder = CertPathBuilder.getInstance("PKIX");
PKIXCertPathBuilderResult result =
(PKIXCertPathBuilderResult) builder.build(params);
prevKey = result.getPublicKey();
} catch (GeneralSecurityException e) {
throw new CRLException(e);
}
}
// check the crl signature algorithm
try {
AlgorithmChecker.check(prevKey, crl);
} catch (CertPathValidatorException cpve) {
if (debug != null) {
debug.println("CRL signature algorithm check failed: " + cpve);
}
return false;
}
// validate the signature on the CRL
try {
crl.verify(prevKey, provider);
} catch (GeneralSecurityException e) {
if (debug != null) {
debug.println("CRL signature failed to verify");
}
return false;
}
// reject CRL if any unresolved critical extensions remain in the CRL.
Set<String> unresCritExts = crl.getCriticalExtensionOIDs();
// remove any that we have processed
if (unresCritExts != null) {
unresCritExts.remove(IssuingDistributionPoint_Id.toString());
if (!unresCritExts.isEmpty()) {
if (debug != null) {
debug.println("Unrecognized critical extension(s) in CRL: "
+ unresCritExts);
for (String ext : unresCritExts) {
debug.println(ext);
}
}
return false;
}
}
// update reasonsMask
for (int i = 0; i < interimReasonsMask.length; i++) {
if (!reasonsMask[i] && interimReasonsMask[i]) {
reasonsMask[i] = true;
}
}
return true;
}
/**
* Append relative name to the issuer name and return a new
* GeneralNames object.
*/
private static GeneralNames getFullNames(X500Name issuer, RDN rdn)
throws IOException
{
List<RDN> rdns = new ArrayList<>(issuer.rdns());
rdns.add(rdn);
X500Name fullName = new X500Name(rdns.toArray(new RDN[0]));
GeneralNames fullNames = new GeneralNames();
fullNames.add(new GeneralName(fullName));
return fullNames;
}
/**
* Verifies whether a CRL is issued by a certain certificate
*
* @param cert the certificate
* @param crl the CRL to be verified
* @param provider the name of the signature provider
*/
private static boolean issues(X509CertImpl cert, X509CRLImpl crl,
String provider) throws IOException
{
boolean matched = false;
AdaptableX509CertSelector issuerSelector =
new AdaptableX509CertSelector();
// check certificate's key usage
boolean[] usages = cert.getKeyUsage();
if (usages != null) {
usages[6] = true; // cRLSign
issuerSelector.setKeyUsage(usages);
}
// check certificate's subject
X500Principal crlIssuer = crl.getIssuerX500Principal();
issuerSelector.setSubject(crlIssuer);
/*
* Facilitate certification path construction with authority
* key identifier and subject key identifier.
*
* In practice, conforming CAs MUST use the key identifier method,
* and MUST include authority key identifier extension in all CRLs
* issued. [section 5.2.1, RFC 2459]
*/
AuthorityKeyIdentifierExtension crlAKID = crl.getAuthKeyIdExtension();
if (crlAKID != null) {
issuerSelector.parseAuthorityKeyIdentifierExtension(crlAKID);
}
matched = issuerSelector.match(cert);
// if AKID is unreliable, verify the CRL signature with the cert
if (matched && (crlAKID == null ||
cert.getAuthorityKeyIdentifierExtension() == null)) {
try {
crl.verify(cert.getPublicKey(), provider);
matched = true;
} catch (GeneralSecurityException e) {
matched = false;
}
}
return matched;
}
}