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 * 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,

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 *

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package sun.security.provider.certpath;

import java.io.IOException;

import java.security.PublicKey;

import java.security.cert.CertificateException;

import java.security.cert.CertPathValidatorException;

import java.security.cert.PKIXCertPathChecker;

import java.security.cert.PKIXRevocationChecker;

import java.security.cert.TrustAnchor;

import java.security.cert.X509Certificate;

import java.util.ArrayList;

import java.util.HashSet;

import java.util.List;

import java.util.ListIterator;

import java.util.Set;

import javax.security.auth.x500.X500Principal;

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

import sun.security.util.Debug;

import sun.security.x509.NameConstraintsExtension;

import sun.security.x509.SubjectKeyIdentifierExtension;

import sun.security.x509.X509CertImpl;

/**

 * A specification of a reverse PKIX validation state

 * which is initialized by each build and updated each time a

 * certificate is added to the current path.

 * @since       1.4

 * @author      Sean Mullan

 * @author      Yassir Elley

 */

class ReverseState implements State {

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

    /* The subject DN of the last cert in the path */

    X500Principal subjectDN;

    /* The subject public key of the last cert */

    PublicKey pubKey;

    /* The subject key identifier extension (if any) of the last cert */

    SubjectKeyIdentifierExtension subjKeyId;

    /* The PKIX constrained/excluded subtrees state variable */

    NameConstraintsExtension nc;

    /* The PKIX explicit policy, policy mapping, and inhibit_any-policy

       state variables */

    int explicitPolicy;

    int policyMapping;

    int inhibitAnyPolicy;

    int certIndex;

    PolicyNodeImpl rootNode;

    /* The number of remaining CA certs which may follow in the path.

     * -1: previous cert was an EE cert

     * 0: only EE certs may follow.

     * >0 and <Integer.MAX_VALUE:no more than this number of CA certs may follow

     * Integer.MAX_VALUE: unlimited

     */

    int remainingCACerts;

    /* The list of user-defined checkers retrieved from the PKIXParameters

     * instance */

    ArrayList<PKIXCertPathChecker> userCheckers;

    /* Flag indicating if state is initial (path is just starting) */

    private boolean init = true;

    /* the checker used for revocation status */

    RevocationChecker revChecker;

    /* the algorithm checker */

    AlgorithmChecker algorithmChecker;

    /* the untrusted certificates checker */

    UntrustedChecker untrustedChecker;

    /* the trust anchor used to validate the path */

    TrustAnchor trustAnchor;

    /* Flag indicating if current cert can vouch for the CRL for

     * the next cert

     */

    boolean crlSign = true;

    /**

     * Returns a boolean flag indicating if the state is initial

     * (just starting)

     *

     * @return boolean flag indicating if the state is initial (just starting)

     */

    @Override

    public boolean isInitial() {

        return init;

    }

    /**

     * Display state for debugging purposes

     */

    @Override

    public String toString() {

        StringBuilder sb = new StringBuilder();

        sb.append("State [");

        sb.append("\n  subjectDN of last cert: ").append(subjectDN);

        sb.append("\n  subjectKeyIdentifier: ").append

                 (String.valueOf(subjKeyId));

        sb.append("\n  nameConstraints: ").append(String.valueOf(nc));

        sb.append("\n  certIndex: ").append(certIndex);

        sb.append("\n  explicitPolicy: ").append(explicitPolicy);

        sb.append("\n  policyMapping:  ").append(policyMapping);

        sb.append("\n  inhibitAnyPolicy:  ").append(inhibitAnyPolicy);

        sb.append("\n  rootNode: ").append(rootNode);

        sb.append("\n  remainingCACerts: ").append(remainingCACerts);

        sb.append("\n  crlSign: ").append(crlSign);

        sb.append("\n  init: ").append(init);

        sb.append("\n]\n");

        return sb.toString();

    }

    /**

     * Initialize the state.

     *

     * @param buildParams builder parameters

     */

    public void initState(BuilderParams buildParams)

        throws CertPathValidatorException

    {

        /*

         * Initialize number of remainingCACerts.

         * Note that -1 maxPathLen implies unlimited.

         * 0 implies only an EE cert is acceptable.

         */

        int maxPathLen = buildParams.maxPathLength();

        remainingCACerts = (maxPathLen == -1) ? Integer.MAX_VALUE

                                              : maxPathLen;

        /* Initialize explicit policy state variable */

        if (buildParams.explicitPolicyRequired()) {

            explicitPolicy = 0;

        } else {

            // unconstrained if maxPathLen is -1,

            // otherwise, we want to initialize this to the value of the

            // longest possible path + 1 (i.e. maxpathlen + finalcert + 1)

            explicitPolicy = (maxPathLen == -1) ? maxPathLen : maxPathLen + 2;

        }

        /* Initialize policy mapping state variable */

        if (buildParams.policyMappingInhibited()) {

            policyMapping = 0;

        } else {

            policyMapping = (maxPathLen == -1) ? maxPathLen : maxPathLen + 2;

        }

        /* Initialize inhibit any policy state variable */

        if (buildParams.anyPolicyInhibited()) {

            inhibitAnyPolicy = 0;

        } else {

            inhibitAnyPolicy = (maxPathLen == -1) ? maxPathLen : maxPathLen + 2;

        }

        /* Initialize certIndex */

        certIndex = 1;

        /* Initialize policy tree */

        Set<String> initExpPolSet = new HashSet<>(1);

        initExpPolSet.add(PolicyChecker.ANY_POLICY);

        rootNode = new PolicyNodeImpl(null, PolicyChecker.ANY_POLICY, null,

                                      false, initExpPolSet, false);

        /*

         * Initialize each user-defined checker

         * Shallow copy the checkers

         */

        userCheckers = new ArrayList<>(buildParams.certPathCheckers());

        /* initialize each checker (just in case) */

        for (PKIXCertPathChecker checker : userCheckers) {

            checker.init(false);

        }

        /* Start by trusting the cert to sign CRLs */

        crlSign = true;

        init = true;

    }

    /**

     * Update the state with the specified trust anchor.

     *

     * @param anchor the most-trusted CA

     * @param buildParams builder parameters

     */

    public void updateState(TrustAnchor anchor, BuilderParams buildParams)

        throws CertificateException, IOException, CertPathValidatorException

    {

        trustAnchor = anchor;

        X509Certificate trustedCert = anchor.getTrustedCert();

        if (trustedCert != null) {

            updateState(trustedCert);

        } else {

            X500Principal caName = anchor.getCA();

            updateState(anchor.getCAPublicKey(), caName);

        }

        // The user specified AlgorithmChecker and RevocationChecker may not be

        // able to set the trust anchor until now.

        boolean revCheckerAdded = false;

        for (PKIXCertPathChecker checker : userCheckers) {

            if (checker instanceof AlgorithmChecker) {

                ((AlgorithmChecker)checker).trySetTrustAnchor(anchor);

            } else if (checker instanceof PKIXRevocationChecker) {

                if (revCheckerAdded) {

                    throw new CertPathValidatorException(

                        "Only one PKIXRevocationChecker can be specified");

                }

                // if it's our own, initialize it

                if (checker instanceof RevocationChecker) {

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

                }

                ((PKIXRevocationChecker)checker).init(false);

                revCheckerAdded = true;

            }

        }

        // only create a RevocationChecker if revocation is enabled and

        // a PKIXRevocationChecker has not already been added

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

            revChecker = new RevocationChecker(anchor, buildParams);

            revChecker.init(false);

        }

        init = false;

    }

    /**

     * Update the state. This method is used when the most-trusted CA is

     * a trusted public-key and caName, instead of a trusted cert.

     *

     * @param pubKey the public key of the trusted CA

     * @param subjectDN the subject distinguished name of the trusted CA

     */

    private void updateState(PublicKey pubKey, X500Principal subjectDN) {

        /* update subject DN */

        this.subjectDN = subjectDN;

        /* update subject public key */

        this.pubKey = pubKey;

    }

    /**

     * Update the state with the next certificate added to the path.

     *

     * @param cert the certificate which is used to update the state

     */

    public void updateState(X509Certificate cert)

        throws CertificateException, IOException, CertPathValidatorException {

        if (cert == null) {

            return;

        }

        /* update subject DN */

        subjectDN = cert.getSubjectX500Principal();

        /* check for key needing to inherit alg parameters */

        X509CertImpl icert = X509CertImpl.toImpl(cert);

        PublicKey newKey = cert.getPublicKey();

        if (PKIX.isDSAPublicKeyWithoutParams(newKey)) {

            newKey = BasicChecker.makeInheritedParamsKey(newKey, pubKey);

        }

        /* update subject public key */

        pubKey = newKey;

        /*

         * if this is a trusted cert (init == true), then we

         * don't update any of the remaining fields

         */

        if (init) {

            init = false;

            return;

        }

        /* update subject key identifier */

        subjKeyId = icert.getSubjectKeyIdentifierExtension();

        /* update crlSign */

        crlSign = RevocationChecker.certCanSignCrl(cert);

        /* update current name constraints */

        if (nc != null) {

            nc.merge(icert.getNameConstraintsExtension());

        } else {

            nc = icert.getNameConstraintsExtension();

            if (nc != null) {

                // 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!

                nc = (NameConstraintsExtension) nc.clone();

            }

        }

        /* update policy state variables */

        explicitPolicy =

            PolicyChecker.mergeExplicitPolicy(explicitPolicy, icert, false);

        policyMapping =

            PolicyChecker.mergePolicyMapping(policyMapping, icert);

        inhibitAnyPolicy =

            PolicyChecker.mergeInhibitAnyPolicy(inhibitAnyPolicy, icert);

        certIndex++;

        /*

         * Update remaining CA certs

         */

        remainingCACerts =

            ConstraintsChecker.mergeBasicConstraints(cert, remainingCACerts);

        init = false;

    }

    /**

     * Returns a boolean flag indicating if a key lacking necessary key

     * algorithm parameters has been encountered.

     *

     * @return boolean flag indicating if key lacking parameters encountered.

     */

    @Override

    public boolean keyParamsNeeded() {

        /* when building in reverse, we immediately get parameters needed

         * or else throw an exception

         */

        return false;

    }

    /*

     * Clone current state. The state is cloned as each cert is

     * added to the path. This is necessary if backtracking occurs,

     * and a prior state needs to be restored.

     *

     * Note that this is a SMART clone. Not all fields are fully copied,

     * because some of them (e.g., subjKeyId) will

     * not have their contents modified by subsequent calls to updateState.

     */

    @Override

    @SuppressWarnings("unchecked") // Safe casts assuming clone() works correctly

    public Object clone() {

        try {

            ReverseState clonedState = (ReverseState) super.clone();

            /* clone checkers, if cloneable */

            clonedState.userCheckers =

                        (ArrayList<PKIXCertPathChecker>)userCheckers.clone();

            ListIterator<PKIXCertPathChecker> li =

                        clonedState.userCheckers.listIterator();

            while (li.hasNext()) {

                PKIXCertPathChecker checker = li.next();

                if (checker instanceof Cloneable) {

                    li.set((PKIXCertPathChecker)checker.clone());

                }

            }

            /* make copy of name constraints */

            if (nc != null) {

                clonedState.nc = (NameConstraintsExtension) nc.clone();

            }

            /* make copy of policy tree */

            if (rootNode != null) {

                clonedState.rootNode = rootNode.copyTree();

            }

            return clonedState;

        } catch (CloneNotSupportedException e) {

            throw new InternalError(e.toString(), e);

        }

    }

}