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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

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 * This code is free software; you can redistribute it and/or modify it

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 * 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,

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 *

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package sun.security.provider.certpath;

import java.io.IOException;

import java.security.InvalidAlgorithmParameterException;

import java.security.cert.*;

import java.util.*;

import sun.security.provider.certpath.PKIX.ValidatorParams;

import sun.security.validator.Validator;

import sun.security.x509.X509CertImpl;

import sun.security.util.Debug;

/**

 * This class implements the PKIX validation algorithm for certification

 * paths consisting exclusively of <code>X509Certificates</code>. It uses

 * the specified input parameter set (which must be a

 * <code>PKIXParameters</code> object).

 *

 * @since       1.4

 * @author      Yassir Elley

 */

public final class PKIXCertPathValidator extends CertPathValidatorSpi {

    private static final Debug debug = Debug.getInstance("certpath");

    /**

     * Default constructor.

     */

    public PKIXCertPathValidator() {}

    @Override

    public CertPathChecker engineGetRevocationChecker() {

        return new RevocationChecker();

    }

    /**

     * Validates a certification path consisting exclusively of

     * <code>X509Certificate</code>s using the PKIX validation algorithm,

     * which uses the specified input parameter set.

     * The input parameter set must be a <code>PKIXParameters</code> object.

     *

     * @param cp the X509 certification path

     * @param params the input PKIX parameter set

     * @return the result

     * @throws CertPathValidatorException if cert path does not validate.

     * @throws InvalidAlgorithmParameterException if the specified

     *         parameters are inappropriate for this CertPathValidator

     */

    @Override

    public CertPathValidatorResult engineValidate(CertPath cp,

                                                  CertPathParameters params)

        throws CertPathValidatorException, InvalidAlgorithmParameterException

    {

        ValidatorParams valParams = PKIX.checkParams(cp, params);

        return validate(valParams);

    }

    private static PKIXCertPathValidatorResult validate(ValidatorParams params)

        throws CertPathValidatorException

    {

        if (debug != null)

            debug.println("PKIXCertPathValidator.engineValidate()...");

        // Retrieve the first certificate in the certpath

        // (to be used later in pre-screening)

        AdaptableX509CertSelector selector = null;

        List<X509Certificate> certList = params.certificates();

        if (!certList.isEmpty()) {

            selector = new AdaptableX509CertSelector();

            X509Certificate firstCert = certList.get(0);

            // check trusted certificate's subject

            selector.setSubject(firstCert.getIssuerX500Principal());

            /*

             * Facilitate certification path construction with authority

             * key identifier and subject key identifier.

             */

            try {

                X509CertImpl firstCertImpl = X509CertImpl.toImpl(firstCert);

                selector.setSkiAndSerialNumber(

                            firstCertImpl.getAuthorityKeyIdentifierExtension());

            } catch (CertificateException | IOException e) {

                // ignore

            }

        }

        CertPathValidatorException lastException = null;

        // We iterate through the set of trust anchors until we find

        // one that works at which time we stop iterating

        for (TrustAnchor anchor : params.trustAnchors()) {

            X509Certificate trustedCert = anchor.getTrustedCert();

            if (trustedCert != null) {

                // if this trust anchor is not worth trying,

                // we move on to the next one

                if (selector != null && !selector.match(trustedCert)) {

                    if (debug != null && Debug.isVerbose()) {

                        debug.println("NO - don't try this trustedCert");

                    }

                    continue;

                }

                if (debug != null) {

                    debug.println("YES - try this trustedCert");

                    debug.println("anchor.getTrustedCert()."

                        + "getSubjectX500Principal() = "

                        + trustedCert.getSubjectX500Principal());

                }

            } else {

                if (debug != null) {

                    debug.println("PKIXCertPathValidator.engineValidate(): "

                        + "anchor.getTrustedCert() == null");

                }

            }

            try {

                return validate(anchor, params);

            } catch (CertPathValidatorException cpe) {

                // remember this exception

                lastException = cpe;

            }

        }

        // could not find a trust anchor that verified

        // (a) if we did a validation and it failed, use that exception

        if (lastException != null) {

            throw lastException;

        }

        // (b) otherwise, generate new exception

        throw new CertPathValidatorException

            ("Path does not chain with any of the trust anchors",

             null, null, -1, PKIXReason.NO_TRUST_ANCHOR);

    }

    private static PKIXCertPathValidatorResult validate(TrustAnchor anchor,

                                                        ValidatorParams params)

        throws CertPathValidatorException

    {

        // check if anchor is untrusted

        UntrustedChecker untrustedChecker = new UntrustedChecker();

        X509Certificate anchorCert = anchor.getTrustedCert();

        if (anchorCert != null) {

            untrustedChecker.check(anchorCert);

        }

        int certPathLen = params.certificates().size();

        // create PKIXCertPathCheckers

        List<PKIXCertPathChecker> certPathCheckers = new ArrayList<>();

        // add standard checkers that we will be using

        certPathCheckers.add(untrustedChecker);

        certPathCheckers.add(new AlgorithmChecker(anchor, null, params.date(),

                params.timestamp(), params.variant()));

        certPathCheckers.add(new KeyChecker(certPathLen,

                                            params.targetCertConstraints()));

        certPathCheckers.add(new ConstraintsChecker(certPathLen));

        PolicyNodeImpl rootNode =

            new PolicyNodeImpl(null, PolicyChecker.ANY_POLICY, null, false,

                               Collections.singleton(PolicyChecker.ANY_POLICY),

                               false);

        PolicyChecker pc = new PolicyChecker(params.initialPolicies(),

                                             certPathLen,

                                             params.explicitPolicyRequired(),

                                             params.policyMappingInhibited(),

                                             params.anyPolicyInhibited(),

                                             params.policyQualifiersRejected(),

                                             rootNode);

        certPathCheckers.add(pc);

        // the time that the certificate validity period should be

        // checked against

        Date timeToCheck = null;

        // use timestamp if checking signed code that is timestamped, otherwise

        // use date parameter from PKIXParameters

        if ((params.variant() == Validator.VAR_CODE_SIGNING ||

             params.variant() == Validator.VAR_PLUGIN_CODE_SIGNING) &&

             params.timestamp() != null) {

            timeToCheck = params.timestamp().getTimestamp();

        } else {

            timeToCheck = params.date();

        }

        BasicChecker bc = new BasicChecker(anchor, timeToCheck,

                                           params.sigProvider(), false);

        certPathCheckers.add(bc);

        boolean revCheckerAdded = false;

        List<PKIXCertPathChecker> checkers = params.certPathCheckers();

        for (PKIXCertPathChecker checker : checkers) {

            if (checker instanceof PKIXRevocationChecker) {

                if (revCheckerAdded) {

                    throw new CertPathValidatorException(

                        "Only one PKIXRevocationChecker can be specified");

                }

                revCheckerAdded = true;

                // if it's our own, initialize it

                if (checker instanceof RevocationChecker) {

                    ((RevocationChecker)checker).init(anchor, params);

                }

            }

        }

        // only add a RevocationChecker if revocation is enabled and

        // a PKIXRevocationChecker has not already been added

        if (params.revocationEnabled() && !revCheckerAdded) {

            certPathCheckers.add(new RevocationChecker(anchor, params));

        }

        // add user-specified checkers

        certPathCheckers.addAll(checkers);

        PKIXMasterCertPathValidator.validate(params.certPath(),

                                             params.certificates(),

                                             certPathCheckers);

        return new PKIXCertPathValidatorResult(anchor, pc.getPolicyTree(),

                                               bc.getPublicKey());

    }

}