/*

 * 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,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

 * or visit www.oracle.com if you need additional information or have any

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 */

/*

 *

 *  (C) Copyright IBM Corp. 1999 All Rights Reserved.

 *  Copyright 1997 The Open Group Research Institute.  All rights reserved.

 */

package sun.security.krb5;

import sun.security.krb5.internal.*;

import sun.security.krb5.internal.crypto.KeyUsage;

import sun.security.util.DerInputStream;

abstract class KrbKdcRep {

    static void check(

                      boolean isAsReq,

                      KDCReq req,

                      KDCRep rep,

                      EncryptionKey replyKey

                      ) throws KrbApErrException {

        // cname change in AS-REP is allowed only if the client

        // sent CANONICALIZE and the server supports RFC 6806 - Section 11

        // FAST scheme (ENC-PA-REP flag).

        if (isAsReq && !req.reqBody.cname.equals(rep.cname) &&

                (!req.reqBody.kdcOptions.get(KDCOptions.CANONICALIZE) ||

                 !rep.encKDCRepPart.flags.get(Krb5.TKT_OPTS_ENC_PA_REP))) {

            rep.encKDCRepPart.key.destroy();

            throw new KrbApErrException(Krb5.KRB_AP_ERR_MODIFIED);

        }

        // sname change in TGS-REP is allowed only if client

        // sent CANONICALIZE and new sname is a referral of

        // the form krbtgt/TO-REALM.COM@FROM-REALM.COM.

        if (!req.reqBody.sname.equals(rep.encKDCRepPart.sname)) {

            String[] snameStrings = rep.encKDCRepPart.sname.getNameStrings();

            if (isAsReq || !req.reqBody.kdcOptions.get(KDCOptions.CANONICALIZE) ||

                    snameStrings == null || snameStrings.length != 2 ||

                    !snameStrings[0].equals(PrincipalName.TGS_DEFAULT_SRV_NAME) ||

                    !rep.encKDCRepPart.sname.getRealmString().equals(

                            req.reqBody.sname.getRealmString())) {

                rep.encKDCRepPart.key.destroy();

                throw new KrbApErrException(Krb5.KRB_AP_ERR_MODIFIED);

            }

        }

        if (req.reqBody.getNonce() != rep.encKDCRepPart.nonce) {

            rep.encKDCRepPart.key.destroy();

            throw new KrbApErrException(Krb5.KRB_AP_ERR_MODIFIED);

        }

        if (

            ((req.reqBody.addresses != null && rep.encKDCRepPart.caddr != null) &&

             !req.reqBody.addresses.equals(rep.encKDCRepPart.caddr))) {

            rep.encKDCRepPart.key.destroy();

            throw new KrbApErrException(Krb5.KRB_AP_ERR_MODIFIED);

        }

        // We allow KDC to return a non-forwardable ticket if request has -f

        for (int i = 2; i < 6; i++) {

            if (req.reqBody.kdcOptions.get(i) !=

                   rep.encKDCRepPart.flags.get(i)) {

                if (Krb5.DEBUG) {

                    System.out.println("> KrbKdcRep.check: at #" + i

                            + ". request for " + req.reqBody.kdcOptions.get(i)

                            + ", received " + rep.encKDCRepPart.flags.get(i));

                }

                throw new KrbApErrException(Krb5.KRB_AP_ERR_MODIFIED);

            }

        }

        // Reply to a renewable request should be renewable, but if request does

        // not contain renewable, KDC is free to issue a renewable ticket (for

        // example, if ticket_lifetime is too big).

        if (req.reqBody.kdcOptions.get(KDCOptions.RENEWABLE) &&

                !rep.encKDCRepPart.flags.get(KDCOptions.RENEWABLE)) {

            throw new KrbApErrException(Krb5.KRB_AP_ERR_MODIFIED);

        }

        if ((req.reqBody.from == null) || req.reqBody.from.isZero()) {

            // verify this is allowed

            if ((rep.encKDCRepPart.starttime != null) &&

                    !rep.encKDCRepPart.starttime.inClockSkew()) {

                rep.encKDCRepPart.key.destroy();

                throw new KrbApErrException(Krb5.KRB_AP_ERR_SKEW);

            }

        }

        if ((req.reqBody.from != null) && !req.reqBody.from.isZero()) {

            // verify this is allowed

            if ((rep.encKDCRepPart.starttime != null) &&

                    !req.reqBody.from.equals(rep.encKDCRepPart.starttime)) {

                rep.encKDCRepPart.key.destroy();

                throw new KrbApErrException(Krb5.KRB_AP_ERR_MODIFIED);

            }

        }

        if (!req.reqBody.till.isZero() &&

                rep.encKDCRepPart.endtime.greaterThan(req.reqBody.till)) {

            rep.encKDCRepPart.key.destroy();

            throw new KrbApErrException(Krb5.KRB_AP_ERR_MODIFIED);

        }

        if (req.reqBody.kdcOptions.get(KDCOptions.RENEWABLE)) {

            if (req.reqBody.rtime != null && !req.reqBody.rtime.isZero()) {

                // verify this is required

                if ((rep.encKDCRepPart.renewTill == null) ||

                        rep.encKDCRepPart.renewTill.greaterThan(req.reqBody.rtime)

                        ) {

                    rep.encKDCRepPart.key.destroy();

                    throw new KrbApErrException(Krb5.KRB_AP_ERR_MODIFIED);

                }

            }

        }

        // RFC 6806 - Section 11 mechanism check

        if (rep.encKDCRepPart.flags.get(Krb5.TKT_OPTS_ENC_PA_REP) &&

                req.reqBody.kdcOptions.get(KDCOptions.CANONICALIZE)) {

            boolean reqPaReqEncPaRep = false;

            boolean repPaReqEncPaRepValid = false;

            // PA_REQ_ENC_PA_REP only required for AS requests

            for (PAData pa : req.pAData) {

                if (pa.getType() == Krb5.PA_REQ_ENC_PA_REP) {

                    reqPaReqEncPaRep = true;

                    break;

                }

            }

            if (rep.encKDCRepPart.pAData != null) {

                for (PAData pa : rep.encKDCRepPart.pAData) {

                    if (pa.getType() == Krb5.PA_REQ_ENC_PA_REP) {

                        try {

                            Checksum repCksum = new Checksum(

                                    new DerInputStream(

                                            pa.getValue()).getDerValue());

                            repPaReqEncPaRepValid =

                                            req.asn1Encode(), replyKey,

                                            KeyUsage.KU_AS_REQ);

                        } catch (Exception e) {

                            if (Krb5.DEBUG) {

                                e.printStackTrace();

                            }

                        }

                        break;

                    }

                }

            }

            if (reqPaReqEncPaRep && !repPaReqEncPaRepValid) {

                throw new KrbApErrException(Krb5.KRB_AP_ERR_MODIFIED);

            }

        }

    }

}