https://openjdk.java.net/ 
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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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package sun.security.provider.certpath;

import java.io.IOException;
import java.security.AccessController;
import java.security.GeneralSecurityException;
import java.security.cert.*;
import java.util.*;

import sun.security.action.GetBooleanAction;
import sun.security.provider.certpath.PKIX.BuilderParams;
import sun.security.util.Debug;
import sun.security.x509.GeneralNames;
import sun.security.x509.GeneralNameInterface;
import sun.security.x509.GeneralSubtrees;
import sun.security.x509.NameConstraintsExtension;
import sun.security.x509.SubjectAlternativeNameExtension;
import sun.security.x509.X500Name;
import sun.security.x509.X509CertImpl;


Abstract class representing a builder, which is able to retrieve
matching certificates and is able to verify a particular certificate.

Author:     Sean Mullan,      Yassir Elley
Since:      1.4
/**
 * Abstract class representing a builder, which is able to retrieve
 * matching certificates and is able to verify a particular certificate.
 *
 * @since       1.4
 * @author      Sean Mullan
 * @author      Yassir Elley
 */

public abstract class Builder {

    private static final Debug debug = Debug.getInstance("certpath");
    private Set<String> matchingPolicies;
    final BuilderParams buildParams;
    final X509CertSelector targetCertConstraints;

    
Flag indicating whether support for the caIssuers field of the
Authority Information Access extension shall be enabled. Currently
disabled by default for compatibility reasons.

/**
     * Flag indicating whether support for the caIssuers field of the
     * Authority Information Access extension shall be enabled. Currently
     * disabled by default for compatibility reasons.
     */
    final static boolean USE_AIA = AccessController.doPrivileged
        (new GetBooleanAction("com.sun.security.enableAIAcaIssuers"));

    
Initialize the builder with the input parameters.

Params:
  • params – the parameter set used to build a certification path
/**
     * Initialize the builder with the input parameters.
     *
     * @param params the parameter set used to build a certification path
     */
    Builder(BuilderParams buildParams) {
        this.buildParams = buildParams;
        this.targetCertConstraints =
            (X509CertSelector)buildParams.targetCertConstraints();
    }

    
Retrieves certificates from the list of certStores using the buildParams
and the currentState as a filter

Params:
  • currentState – the current State
  • certStores – list of CertStores
/**
     * Retrieves certificates from the list of certStores using the buildParams
     * and the currentState as a filter
     *
     * @param currentState the current State
     * @param certStores list of CertStores
     */
    abstract Collection<X509Certificate> getMatchingCerts
        (State currentState, List<CertStore> certStores)
        throws CertStoreException, CertificateException, IOException;

    
Verifies the cert against the currentState, using the certPathList
generated thus far to help with loop detection

Params:
  • cert – the certificate to be verified
  • currentState – the current state against which the cert is verified
  • certPathList – the certPathList generated thus far
/**
     * Verifies the cert against the currentState, using the certPathList
     * generated thus far to help with loop detection
     *
     * @param cert the certificate to be verified
     * @param currentState the current state against which the cert is verified
     * @param certPathList the certPathList generated thus far
     */
    abstract void verifyCert(X509Certificate cert, State currentState,
                             List<X509Certificate> certPathList)
        throws GeneralSecurityException;

    
Verifies whether the input certificate completes the path.
When building in the forward direction, a trust anchor will
complete the path.

Params:
  • cert – the certificate to test
Returns:a boolean value indicating whether the cert completes the path.
/**
     * Verifies whether the input certificate completes the path.
     * When building in the forward direction, a trust anchor will
     * complete the path.
     *
     * @param cert the certificate to test
     * @return a boolean value indicating whether the cert completes the path.
     */
    abstract boolean isPathCompleted(X509Certificate cert);

    
Adds the certificate to the certPathList

Params:
  • cert – the certificate to be added
  • certPathList – the certification path list
/**
     * Adds the certificate to the certPathList
     *
     * @param cert the certificate to be added
     * @param certPathList the certification path list
     */
    abstract void addCertToPath(X509Certificate cert,
                                LinkedList<X509Certificate> certPathList);

    
Removes final certificate from the certPathList

Params:
  • certPathList – the certification path list
/**
     * Removes final certificate from the certPathList
     *
     * @param certPathList the certification path list
     */
    abstract void removeFinalCertFromPath
        (LinkedList<X509Certificate> certPathList);

    
get distance of one GeneralName from another

Params:
  • base – GeneralName at base of subtree
  • test – GeneralName to be tested against base
  • incomparable – the value to return if the names are
 incomparable
Returns:distance of test name from base, where 0
        means exact match, 1 means test is an immediate
        child of base, 2 means test is a grandchild, etc.
        -1 means test is a parent of base, -2 means test
        is a grandparent, etc.
/**
     * get distance of one GeneralName from another
     *
     * @param base GeneralName at base of subtree
     * @param test GeneralName to be tested against base
     * @param incomparable the value to return if the names are
     *  incomparable
     * @return distance of test name from base, where 0
     *         means exact match, 1 means test is an immediate
     *         child of base, 2 means test is a grandchild, etc.
     *         -1 means test is a parent of base, -2 means test
     *         is a grandparent, etc.
     */
    static int distance(GeneralNameInterface base,
                        GeneralNameInterface test, int incomparable)
    {
        switch (base.constrains(test)) {
        case GeneralNameInterface.NAME_DIFF_TYPE:
            if (debug != null) {
                debug.println("Builder.distance(): Names are different types");
            }
            return incomparable;
        case GeneralNameInterface.NAME_SAME_TYPE:
            if (debug != null) {
                debug.println("Builder.distance(): Names are same type but " +
                    "in different subtrees");
            }
            return incomparable;
        case GeneralNameInterface.NAME_MATCH:
            return 0;
        case GeneralNameInterface.NAME_WIDENS:
            break;
        case GeneralNameInterface.NAME_NARROWS:
            break;
        default: // should never occur
            return incomparable;
        }

        /* names are in same subtree */
        return test.subtreeDepth() - base.subtreeDepth();
    }

    
get hop distance of one GeneralName from another in links where
the names need not have an ancestor/descendant relationship.
For example, the hop distance from ou=D,ou=C,o=B,c=US to
ou=F,ou=E,ou=C,o=B,c=US is 3: D->C, C->E, E->F.  The hop distance
from ou=C,o=B,c=US to ou=D,ou=C,o=B,c=US is -1: C->D

Params:
  • base – GeneralName
  • test – GeneralName to be tested against base
  • incomparable – the value to return if the names are
 incomparable
Returns:distance of test name from base measured in hops in the
        namespace hierarchy, where 0 means exact match.  Result
        is positive if path is some number of up hops followed by
        some number of down hops; result is negative if path is
        some number of down hops.
/**
     * get hop distance of one GeneralName from another in links where
     * the names need not have an ancestor/descendant relationship.
     * For example, the hop distance from ou=D,ou=C,o=B,c=US to
     * ou=F,ou=E,ou=C,o=B,c=US is 3: D->C, C->E, E->F.  The hop distance
     * from ou=C,o=B,c=US to ou=D,ou=C,o=B,c=US is -1: C->D
     *
     * @param base GeneralName
     * @param test GeneralName to be tested against base
     * @param incomparable the value to return if the names are
     *  incomparable
     * @return distance of test name from base measured in hops in the
     *         namespace hierarchy, where 0 means exact match.  Result
     *         is positive if path is some number of up hops followed by
     *         some number of down hops; result is negative if path is
     *         some number of down hops.
     */
    static int hops(GeneralNameInterface base, GeneralNameInterface test,
                    int incomparable)
    {
        int baseRtest = base.constrains(test);
        switch (baseRtest) {
        case GeneralNameInterface.NAME_DIFF_TYPE:
            if (debug != null) {
                debug.println("Builder.hops(): Names are different types");
            }
            return incomparable;
        case GeneralNameInterface.NAME_SAME_TYPE:
            /* base and test are in different subtrees */
            break;
        case GeneralNameInterface.NAME_MATCH:
            /* base matches test */
            return 0;
        case GeneralNameInterface.NAME_WIDENS:
            /* base is ancestor of test */
            return (test.subtreeDepth()-base.subtreeDepth());
        case GeneralNameInterface.NAME_NARROWS:
            /* base is descendant of test */
            return (test.subtreeDepth()-base.subtreeDepth());
        default: // should never occur
            return incomparable;
        }

        /* names are in different subtrees */
        if (base.getType() != GeneralNameInterface.NAME_DIRECTORY) {
            if (debug != null) {
                debug.println("Builder.hops(): hopDistance not implemented " +
                    "for this name type");
            }
            return incomparable;
        }
        X500Name baseName = (X500Name)base;
        X500Name testName = (X500Name)test;
        X500Name commonName = baseName.commonAncestor(testName);
        if (commonName == null) {
            if (debug != null) {
                debug.println("Builder.hops(): Names are in different " +
                    "namespaces");
            }
            return incomparable;
        } else {
            int commonDistance = commonName.subtreeDepth();
            int baseDistance = baseName.subtreeDepth();
            int testDistance = testName.subtreeDepth();
            return (baseDistance + testDistance - (2 * commonDistance));
        }
    }

    
Determine how close a given certificate gets you toward
a given target.

Params:
  • constraints – Current NameConstraints; if null,
       then caller must verify NameConstraints
       independently, realizing that this certificate
       may not actually lead to the target at all.
  • cert – Candidate certificate for chain
  • target – GeneralNameInterface name of target
Throws:
Returns:distance from this certificate to target:

    

  • -1 means certificate could be CA for target, but
    there are no NameConstraints limiting how close

  •  0 means certificate subject or subjectAltName
     matches target

  •  1 means certificate is permitted to be CA for
     target.

  •  2 means certificate is permitted to be CA for
     parent of target.

  • >0 in general, means certificate is permitted
    to be a CA for this distance higher in the naming
    hierarchy than the target, plus 1.



Note that the subject and/or subjectAltName of the
candidate cert does not have to be an ancestor of the
target in order to be a CA that can issue a certificate to
the target. In these cases, the target distance is calculated
by inspecting the NameConstraints extension in the candidate
certificate. For example, suppose the target is an X.500 DN with
a value of "CN=mullan,OU=ireland,O=sun,C=us" and the
NameConstraints extension in the candidate certificate
includes a permitted component of "O=sun,C=us", which implies
that the candidate certificate is allowed to issue certs in
the "O=sun,C=us" namespace. The target distance is 3
((distance of permitted NC from target) + 1).
The (+1) is added to distinguish the result from the case
which returns (0).
/**
     * Determine how close a given certificate gets you toward
     * a given target.
     *
     * @param constraints Current NameConstraints; if null,
     *        then caller must verify NameConstraints
     *        independently, realizing that this certificate
     *        may not actually lead to the target at all.
     * @param cert Candidate certificate for chain
     * @param target GeneralNameInterface name of target
     * @return distance from this certificate to target:
     * <ul>
     * <li>-1 means certificate could be CA for target, but
     *     there are no NameConstraints limiting how close
     * <li> 0 means certificate subject or subjectAltName
     *      matches target
     * <li> 1 means certificate is permitted to be CA for
     *      target.
     * <li> 2 means certificate is permitted to be CA for
     *      parent of target.
     * <li>&gt;0 in general, means certificate is permitted
     *     to be a CA for this distance higher in the naming
     *     hierarchy than the target, plus 1.
     * </ul>
     * <p>Note that the subject and/or subjectAltName of the
     * candidate cert does not have to be an ancestor of the
     * target in order to be a CA that can issue a certificate to
     * the target. In these cases, the target distance is calculated
     * by inspecting the NameConstraints extension in the candidate
     * certificate. For example, suppose the target is an X.500 DN with
     * a value of "CN=mullan,OU=ireland,O=sun,C=us" and the
     * NameConstraints extension in the candidate certificate
     * includes a permitted component of "O=sun,C=us", which implies
     * that the candidate certificate is allowed to issue certs in
     * the "O=sun,C=us" namespace. The target distance is 3
     * ((distance of permitted NC from target) + 1).
     * The (+1) is added to distinguish the result from the case
     * which returns (0).
     * @throws IOException if certificate does not get closer
     */
    static int targetDistance(NameConstraintsExtension constraints,
                              X509Certificate cert, GeneralNameInterface target)
            throws IOException
    {
        /* ensure that certificate satisfies existing name constraints */
        if (constraints != null && !constraints.verify(cert)) {
            throw new IOException("certificate does not satisfy existing name "
                + "constraints");
        }

        X509CertImpl certImpl;
        try {
            certImpl = X509CertImpl.toImpl(cert);
        } catch (CertificateException e) {
            throw new IOException("Invalid certificate", e);
        }
        /* see if certificate subject matches target */
        X500Name subject = X500Name.asX500Name(certImpl.getSubjectX500Principal());
        if (subject.equals(target)) {
            /* match! */
            return 0;
        }

        SubjectAlternativeNameExtension altNameExt =
            certImpl.getSubjectAlternativeNameExtension();
        if (altNameExt != null) {
            GeneralNames altNames = altNameExt.get(
                    SubjectAlternativeNameExtension.SUBJECT_NAME);
            /* see if any alternative name matches target */
            if (altNames != null) {
                for (int j = 0, n = altNames.size(); j < n; j++) {
                    GeneralNameInterface altName = altNames.get(j).getName();
                    if (altName.equals(target)) {
                        return 0;
                    }
                }
            }
        }


        /* no exact match; see if certificate can get us to target */

        /* first, get NameConstraints out of certificate */
        NameConstraintsExtension ncExt = certImpl.getNameConstraintsExtension();
        if (ncExt == null) {
            return -1;
        }

        /* merge certificate's NameConstraints with current NameConstraints */
        if (constraints != null) {
            constraints.merge(ncExt);
        } else {
            // Make sure we do a clone here, because we're probably
            // going to modify this object later and we don't want to
            // be sharing it with a Certificate object!
            constraints = (NameConstraintsExtension) ncExt.clone();
        }

        if (debug != null) {
            debug.println("Builder.targetDistance() merged constraints: "
                + String.valueOf(constraints));
        }
        /* reduce permitted by excluded */
        GeneralSubtrees permitted =
                constraints.get(NameConstraintsExtension.PERMITTED_SUBTREES);
        GeneralSubtrees excluded =
                constraints.get(NameConstraintsExtension.EXCLUDED_SUBTREES);
        if (permitted != null) {
            permitted.reduce(excluded);
        }
        if (debug != null) {
            debug.println("Builder.targetDistance() reduced constraints: "
                + permitted);
        }
        /* see if new merged constraints allow target */
        if (!constraints.verify(target)) {
            throw new IOException("New certificate not allowed to sign "
                + "certificate for target");
        }
        /* find distance to target, if any, in permitted */
        if (permitted == null) {
            /* certificate is unconstrained; could sign for anything */
            return -1;
        }
        for (int i = 0, n = permitted.size(); i < n; i++) {
            GeneralNameInterface perName = permitted.get(i).getName().getName();
            int distance = distance(perName, target, -1);
            if (distance >= 0) {
                return (distance + 1);
            }
        }
        /* no matching type in permitted; cert holder could certify target */
        return -1;
    }

    
This method can be used as an optimization to filter out
certificates that do not have policies which are valid.
It returns the set of policies (String OIDs) that should exist in
the certificate policies extension of the certificate that is
needed by the builder. The logic applied is as follows:


  1) If some initial policies have been set *and* policy mappings are
  inhibited, then acceptable certificates are those that include
  the ANY_POLICY OID or with policies that intersect with the
  initial policies.
  2) If no initial policies have been set *or* policy mappings are
  not inhibited then we don't have much to work with. All we know is
  that a certificate must have *some* policy because if it didn't
  have any policy then the policy tree would become null (and validation
  would fail).

Returns:the Set of policies any of which must exist in a
cert's certificate policies extension in order for a cert to be selected.
/**
     * This method can be used as an optimization to filter out
     * certificates that do not have policies which are valid.
     * It returns the set of policies (String OIDs) that should exist in
     * the certificate policies extension of the certificate that is
     * needed by the builder. The logic applied is as follows:
     * <p>
     *   1) If some initial policies have been set *and* policy mappings are
     *   inhibited, then acceptable certificates are those that include
     *   the ANY_POLICY OID or with policies that intersect with the
     *   initial policies.
     *   2) If no initial policies have been set *or* policy mappings are
     *   not inhibited then we don't have much to work with. All we know is
     *   that a certificate must have *some* policy because if it didn't
     *   have any policy then the policy tree would become null (and validation
     *   would fail).
     *
     * @return the Set of policies any of which must exist in a
     * cert's certificate policies extension in order for a cert to be selected.
     */
    Set<String> getMatchingPolicies() {
        if (matchingPolicies != null) {
            Set<String> initialPolicies = buildParams.initialPolicies();
            if ((!initialPolicies.isEmpty()) &&
                (!initialPolicies.contains(PolicyChecker.ANY_POLICY)) &&
                (buildParams.policyMappingInhibited()))
            {
                matchingPolicies = new HashSet<>(initialPolicies);
                matchingPolicies.add(PolicyChecker.ANY_POLICY);
            } else {
                // we just return an empty set to make sure that there is
                // at least a certificate policies extension in the cert
                matchingPolicies = Collections.<String>emptySet();
            }
        }
        return matchingPolicies;
    }

    
Search the specified CertStores and add all certificates matching
selector to resultCerts. Self-signed certs are not useful here
and therefore ignored.
If the targetCert criterion of the selector is set, only that cert
is examined and the CertStores are not searched.
If checkAll is true, all CertStores are searched for matching certs.
If false, the method returns as soon as the first CertStore returns
a matching cert(s).
Returns true iff resultCerts changed (a cert was added to the collection)

/**
     * Search the specified CertStores and add all certificates matching
     * selector to resultCerts. Self-signed certs are not useful here
     * and therefore ignored.
     *
     * If the targetCert criterion of the selector is set, only that cert
     * is examined and the CertStores are not searched.
     *
     * If checkAll is true, all CertStores are searched for matching certs.
     * If false, the method returns as soon as the first CertStore returns
     * a matching cert(s).
     *
     * Returns true iff resultCerts changed (a cert was added to the collection)
     */
    boolean addMatchingCerts(X509CertSelector selector,
                             Collection<CertStore> certStores,
                             Collection<X509Certificate> resultCerts,
                             boolean checkAll)
    {
        X509Certificate targetCert = selector.getCertificate();
        if (targetCert != null) {
            // no need to search CertStores
            if (selector.match(targetCert) && !X509CertImpl.isSelfSigned
                (targetCert, buildParams.sigProvider())) {
                if (debug != null) {
                    debug.println("Builder.addMatchingCerts: " +
                        "adding target cert" +
                        "\n  SN: " + Debug.toHexString(
                                            targetCert.getSerialNumber()) +
                        "\n  Subject: " + targetCert.getSubjectX500Principal() +
                        "\n  Issuer: " + targetCert.getIssuerX500Principal());
                }
                return resultCerts.add(targetCert);
            }
            return false;
        }
        boolean add = false;
        for (CertStore store : certStores) {
            try {
                Collection<? extends Certificate> certs =
                                        store.getCertificates(selector);
                for (Certificate cert : certs) {
                    if (!X509CertImpl.isSelfSigned
                        ((X509Certificate)cert, buildParams.sigProvider())) {
                        if (resultCerts.add((X509Certificate)cert)) {
                            add = true;
                        }
                    }
                }
                if (!checkAll && add) {
                    return true;
                }
            } catch (CertStoreException cse) {
                // if getCertificates throws a CertStoreException, we ignore
                // it and move on to the next CertStore
                if (debug != null) {
                    debug.println("Builder.addMatchingCerts, non-fatal " +
                        "exception retrieving certs: " + cse);
                    cse.printStackTrace();
                }
            }
        }
        return add;
    }
}