usr/src/cmd/krb5/krb5kdc/do_tgs_req.c

   1 /*
   2  * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
   3  * Use is subject to license terms.
   4  */
   5
   6
   7 /*
   8  * kdc/do_tgs_req.c
   9  *
  10  * Copyright 1990,1991,2001 by the Massachusetts Institute of Technology.
  11  * All Rights Reserved.
  12  *
  13  * Export of this software from the United States of America may
  14  *   require a specific license from the United States Government.
  15  *   It is the responsibility of any person or organization contemplating
  16  *   export to obtain such a license before exporting.
  17  *
  18  * WITHIN THAT CONSTRAINT, permission to use, copy, modify, and
  19  * distribute this software and its documentation for any purpose and
  20  * without fee is hereby granted, provided that the above copyright
  21  * notice appear in all copies and that both that copyright notice and
  22  * this permission notice appear in supporting documentation, and that
  23  * the name of M.I.T. not be used in advertising or publicity pertaining
  24  * to distribution of the software without specific, written prior
  25  * permission.  Furthermore if you modify this software you must label
  26  * your software as modified software and not distribute it in such a
  27  * fashion that it might be confused with the original M.I.T. software.
  28  * M.I.T. makes no representations about the suitability of
  29  * this software for any purpose.  It is provided "as is" without express
  30  * or implied warranty.
  31  *
  32  *
  33  * KDC Routines to deal with TGS_REQ's
  34  */
  35
  36 #include "k5-int.h"
  37 #include "com_err.h"
  38
  39 #include <syslog.h>
  40 #ifdef HAVE_NETINET_IN_H
  41 #include <sys/types.h>
  42 #include <netinet/in.h>
  43 #ifndef hpux
  44 #include <arpa/inet.h>
  45 #endif
  46 #endif
  47
  48 #include "kdc_util.h"
  49 #include "policy.h"
  50 #include "extern.h"
  51 #include "adm_proto.h"
  52
  53 extern krb5_error_code setup_server_realm(krb5_principal);
  54
  55 static void find_alternate_tgs (krb5_kdc_req *, krb5_db_entry *,
  56                                 krb5_boolean *, int *,
  57                                 const krb5_fulladdr *from, char *cname);
  58
  59 static krb5_error_code prepare_error_tgs (krb5_kdc_req *, krb5_ticket *,
  60                                           int, const char *, krb5_data **,
  61                                           const char *);
  62
  63 /*ARGSUSED*/
  64 krb5_error_code
  65 process_tgs_req(krb5_data *pkt, const krb5_fulladdr *from,
  66                 krb5_data **response)
  67 {
  68     krb5_keyblock * subkey;
  69     krb5_kdc_req *request = 0;
  70     krb5_db_entry server;
  71     krb5_kdc_rep reply;
  72     krb5_enc_kdc_rep_part reply_encpart;
  73     krb5_ticket ticket_reply, *header_ticket = 0;
  74     int st_idx = 0;
  75     krb5_enc_tkt_part enc_tkt_reply;
  76     krb5_transited enc_tkt_transited;
  77     int newtransited = 0;
  78     krb5_error_code retval = 0;
  79     int nprincs = 0;
  80     krb5_boolean more;
  81     krb5_timestamp kdc_time, authtime=0;
  82     krb5_keyblock session_key;
  83     krb5_timestamp until, rtime;
  84     krb5_keyblock encrypting_key;
  85     krb5_key_data  *server_key;
  86     char *cname = 0, *sname = 0, *tmp = 0;
  87     const char *fromstring = 0;
  88     krb5_last_req_entry *nolrarray[2], nolrentry;
  89 /*    krb5_address *noaddrarray[1]; */
  90     krb5_enctype useenctype;
  91     int errcode, errcode2;
  92     register int i;
  93     int firstpass = 1;
  94     const char  *status = 0;
  95     char ktypestr[128];
  96     char rep_etypestr[128];
  97     char fromstringbuf[70];
  98     long long tmp_server_times, tmp_realm_times;
  99
 100     (void) memset(&encrypting_key, 0, sizeof(krb5_keyblock));
 101     (void) memset(&session_key, 0, sizeof(krb5_keyblock));
 102
 103     retval = decode_krb5_tgs_req(pkt, &request);
 104     if (retval)
 105         return retval;
 106
 107     ktypes2str(ktypestr, sizeof(ktypestr),
 108                request->nktypes, request->ktype);
 109     /*
 110      * setup_server_realm() sets up the global realm-specific data pointer.
 111      */
 112     if ((retval = setup_server_realm(request->server)))
 113         return retval;
 114
 115     fromstring = inet_ntop(ADDRTYPE2FAMILY(from->address->addrtype),
 116                            from->address->contents,
 117                            fromstringbuf, sizeof(fromstringbuf));
 118     if (!fromstring)
 119         fromstring = "<unknown>";
 120
 121     if ((errcode = krb5_unparse_name(kdc_context, request->server, &sname))) {
 122         status = "UNPARSING SERVER";
 123         goto cleanup;
 124     }
 125     limit_string(sname);
 126
 127    /* errcode = kdc_process_tgs_req(request, from, pkt, &req_authdat); */
 128     errcode = kdc_process_tgs_req(request, from, pkt, &header_ticket, &subkey);
 129
 130     if (header_ticket && header_ticket->enc_part2 &&
 131         (errcode2 = krb5_unparse_name(kdc_context,
 132                                       header_ticket->enc_part2->client,
 133                                       &cname))) {
 134         status = "UNPARSING CLIENT";
 135         errcode = errcode2;
 136         goto cleanup;
 137     }
 138     limit_string(cname);
 139
 140     if (errcode) {
 141         status = "PROCESS_TGS";
 142         goto cleanup;
 143     }
 144
 145     if (!header_ticket) {
 146         errcode = KRB5_NO_TKT_SUPPLIED; /* XXX? */
 147         status="UNEXPECTED NULL in header_ticket";
 148         goto cleanup;
 149     }
 150
 151     /*
 152      * We've already dealt with the AP_REQ authentication, so we can
 153      * use header_ticket freely.  The encrypted part (if any) has been
 154      * decrypted with the session key.
 155      */
 156
 157     authtime = header_ticket->enc_part2->times.authtime;
 158
 159     /* XXX make sure server here has the proper realm...taken from AP_REQ
 160        header? */
 161
 162     nprincs = 1;
 163     if ((errcode = krb5_db_get_principal(kdc_context, request->server, &server,
 164                                         &nprincs, &more))) {
 165         status = "LOOKING_UP_SERVER";
 166         nprincs = 0;
 167         goto cleanup;
 168     }
 169 tgt_again:
 170     if (more) {
 171         status = "NON_UNIQUE_PRINCIPAL";
 172         errcode = KRB5KDC_ERR_PRINCIPAL_NOT_UNIQUE;
 173         goto cleanup;
 174     } else if (nprincs != 1) {
 175         /*
 176          * might be a request for a TGT for some other realm; we
 177          * should do our best to find such a TGS in this db
 178          */
 179         if (firstpass && krb5_is_tgs_principal(request->server) == TRUE) {
 180             if (krb5_princ_size(kdc_context, request->server) == 2) {
 181                 krb5_data *server_1 =
 182                     krb5_princ_component(kdc_context, request->server, 1);
 183                 krb5_data *tgs_1 =
 184                     krb5_princ_component(kdc_context, tgs_server, 1);
 185
 186                 if (!tgs_1 || server_1->length != tgs_1->length ||
 187                     memcmp(server_1->data, tgs_1->data, tgs_1->length)) {
 188                     krb5_db_free_principal(kdc_context, &server, nprincs);
 189                     find_alternate_tgs(request, &server, &more, &nprincs,
 190                                       from, cname);
 191                     firstpass = 0;
 192                     goto tgt_again;
 193                 }
 194             }
 195         }
 196         krb5_db_free_principal(kdc_context, &server, nprincs);
 197         status = "UNKNOWN_SERVER";
 198         errcode = KRB5KDC_ERR_S_PRINCIPAL_UNKNOWN;
 199         goto cleanup;
 200     }
 201
 202     if ((errcode = krb5_timeofday(kdc_context, &kdc_time))) {
 203         status = "TIME_OF_DAY";
 204         goto cleanup;
 205     }
 206
 207     if ((retval = validate_tgs_request(request, server, header_ticket,
 208                                       kdc_time, &status))) {
 209         if (!status)
 210             status = "UNKNOWN_REASON";
 211         errcode = retval + ERROR_TABLE_BASE_krb5;
 212         goto cleanup;
 213     }
 214
 215     /*
 216      * We pick the session keytype here....
 217      *
 218      * Some special care needs to be taken in the user-to-user
 219      * case, since we don't know what keytypes the application server
 220      * which is doing user-to-user authentication can support.  We
 221      * know that it at least must be able to support the encryption
 222      * type of the session key in the TGT, since otherwise it won't be
 223      * able to decrypt the U2U ticket!  So we use that in preference
 224      * to anything else.
 225      */
 226     useenctype = 0;
 227     if (isflagset(request->kdc_options, KDC_OPT_ENC_TKT_IN_SKEY)) {
 228         krb5_keyblock * st_sealing_key;
 229         krb5_kvno       st_srv_kvno;
 230         krb5_enctype    etype;
 231
 232         /*
 233          * Get the key for the second ticket, and decrypt it.
 234          */
 235         if ((errcode = kdc_get_server_key(request->second_ticket[st_idx],
 236                                          &st_sealing_key,
 237                                          &st_srv_kvno))) {
 238             status = "2ND_TKT_SERVER";
 239             goto cleanup;
 240         }
 241         errcode = krb5_decrypt_tkt_part(kdc_context, st_sealing_key,
 242                                        request->second_ticket[st_idx]);
 243         krb5_free_keyblock(kdc_context, st_sealing_key);
 244         if (errcode) {
 245             status = "2ND_TKT_DECRYPT";
 246             goto cleanup;
 247         }
 248
 249         etype = request->second_ticket[st_idx]->enc_part2->session->enctype;
 250         if (!krb5_c_valid_enctype(etype)) {
 251             status = "BAD_ETYPE_IN_2ND_TKT";
 252             errcode = KRB5KDC_ERR_ETYPE_NOSUPP;
 253             goto cleanup;
 254         }
 255
 256         for (i = 0; i < request->nktypes; i++) {
 257             if (request->ktype[i] == etype) {
 258                 useenctype = etype;
 259                 break;
 260             }
 261         }
 262     }
 263
 264     /*
 265      * Select the keytype for the ticket session key.
 266      */
 267     if ((useenctype == 0) &&
 268         (useenctype = select_session_keytype(kdc_context, &server,
 269                                              request->nktypes,
 270                                              request->ktype)) == 0) {
 271         /* unsupported ktype */
 272         status = "BAD_ENCRYPTION_TYPE";
 273         errcode = KRB5KDC_ERR_ETYPE_NOSUPP;
 274         goto cleanup;
 275     }
 276
 277     errcode = krb5_c_make_random_key(kdc_context, useenctype, &session_key);
 278
 279     if (errcode) {
 280         /* random key failed */
 281         status = "RANDOM_KEY_FAILED";
 282         goto cleanup;
 283     }
 284
 285     ticket_reply.server = request->server; /* XXX careful for realm... */
 286
 287     enc_tkt_reply.flags = 0;
 288     enc_tkt_reply.times.starttime = 0;
 289
 290     /*
 291      * Fix header_ticket's starttime; if it's zero, fill in the
 292      * authtime's value.
 293      */
 294     if (!(header_ticket->enc_part2->times.starttime))
 295         header_ticket->enc_part2->times.starttime =
 296             header_ticket->enc_part2->times.authtime;
 297
 298     /* don't use new addresses unless forwarded, see below */
 299
 300     enc_tkt_reply.caddrs = header_ticket->enc_part2->caddrs;
 301     /* noaddrarray[0] = 0; */
 302     reply_encpart.caddrs = 0;           /* optional...don't put it in */
 303
 304     /* It should be noted that local policy may affect the  */
 305     /* processing of any of these flags.  For example, some */
 306     /* realms may refuse to issue renewable tickets         */
 307
 308     if (isflagset(request->kdc_options, KDC_OPT_FORWARDABLE))
 309         setflag(enc_tkt_reply.flags, TKT_FLG_FORWARDABLE);
 310
 311     if (isflagset(request->kdc_options, KDC_OPT_FORWARDED)) {
 312         setflag(enc_tkt_reply.flags, TKT_FLG_FORWARDED);
 313
 314         /* include new addresses in ticket & reply */
 315
 316         enc_tkt_reply.caddrs = request->addresses;
 317         reply_encpart.caddrs = request->addresses;
 318     }
 319     if (isflagset(header_ticket->enc_part2->flags, TKT_FLG_FORWARDED))
 320         setflag(enc_tkt_reply.flags, TKT_FLG_FORWARDED);
 321
 322     if (isflagset(request->kdc_options, KDC_OPT_PROXIABLE))
 323         setflag(enc_tkt_reply.flags, TKT_FLG_PROXIABLE);
 324
 325     if (isflagset(request->kdc_options, KDC_OPT_PROXY)) {
 326         setflag(enc_tkt_reply.flags, TKT_FLG_PROXY);
 327
 328         /* include new addresses in ticket & reply */
 329
 330         enc_tkt_reply.caddrs = request->addresses;
 331         reply_encpart.caddrs = request->addresses;
 332     }
 333
 334     if (isflagset(request->kdc_options, KDC_OPT_ALLOW_POSTDATE))
 335         setflag(enc_tkt_reply.flags, TKT_FLG_MAY_POSTDATE);
 336
 337     if (isflagset(request->kdc_options, KDC_OPT_POSTDATED)) {
 338         setflag(enc_tkt_reply.flags, TKT_FLG_POSTDATED);
 339         setflag(enc_tkt_reply.flags, TKT_FLG_INVALID);
 340         enc_tkt_reply.times.starttime = request->from;
 341     } else
 342         enc_tkt_reply.times.starttime = kdc_time;
 343
 344     if (isflagset(request->kdc_options, KDC_OPT_VALIDATE)) {
 345         /* BEWARE of allocation hanging off of ticket & enc_part2, it belongs
 346            to the caller */
 347         ticket_reply = *(header_ticket);
 348         enc_tkt_reply = *(header_ticket->enc_part2);
 349         clear(enc_tkt_reply.flags, TKT_FLG_INVALID);
 350     }
 351
 352     if (isflagset(request->kdc_options, KDC_OPT_RENEW)) {
 353         krb5_deltat old_life;
 354
 355         /* BEWARE of allocation hanging off of ticket & enc_part2, it belongs
 356            to the caller */
 357         ticket_reply = *(header_ticket);
 358         enc_tkt_reply = *(header_ticket->enc_part2);
 359
 360         old_life = enc_tkt_reply.times.endtime - enc_tkt_reply.times.starttime;
 361
 362         enc_tkt_reply.times.starttime = kdc_time;
 363         enc_tkt_reply.times.endtime =
 364             min(header_ticket->enc_part2->times.renew_till,
 365                 kdc_time + old_life);
 366     } else {
 367         /* not a renew request */
 368         enc_tkt_reply.times.starttime = kdc_time;
 369         until = (request->till == 0) ? kdc_infinity : request->till;
 370
 371         /* SUNW */
 372         tmp_server_times = (long long) enc_tkt_reply.times.starttime
 373           + server.max_life;
 374
 375         tmp_realm_times = (long long) enc_tkt_reply.times.starttime
 376           + max_life_for_realm;
 377
 378         enc_tkt_reply.times.endtime =
 379           min(until,
 380             min(tmp_server_times,
 381                 min(tmp_realm_times,
 382                         min(header_ticket->enc_part2->times.endtime,
 383                             KRB5_KDB_EXPIRATION)))); /* SUNW */
 384 /*
 385         enc_tkt_reply.times.endtime =
 386             min(until, min(enc_tkt_reply.times.starttime + server.max_life,
 387                            min(enc_tkt_reply.times.starttime + max_life_for_realm,
 388                                min(header_ticket->enc_part2->times.endtime)));
 389 */
 390         if (isflagset(request->kdc_options, KDC_OPT_RENEWABLE_OK) &&
 391             (enc_tkt_reply.times.endtime < request->till) &&
 392             isflagset(header_ticket->enc_part2->flags,
 393                   TKT_FLG_RENEWABLE)) {
 394             setflag(request->kdc_options, KDC_OPT_RENEWABLE);
 395             request->rtime =
 396                 min(request->till,
 397                     min(KRB5_KDB_EXPIRATION,
 398                     header_ticket->enc_part2->times.renew_till));
 399         }
 400     }
 401     rtime = (request->rtime == 0) ? kdc_infinity : request->rtime;
 402
 403     if (isflagset(request->kdc_options, KDC_OPT_RENEWABLE)) {
 404         /* already checked above in policy check to reject request for a
 405            renewable ticket using a non-renewable ticket */
 406         setflag(enc_tkt_reply.flags, TKT_FLG_RENEWABLE);
 407         tmp_realm_times =  (long long) enc_tkt_reply.times.starttime +
 408                 min(server.max_renewable_life,max_renewable_life_for_realm);
 409         enc_tkt_reply.times.renew_till =
 410             min(rtime,
 411                 min(header_ticket->enc_part2->times.renew_till,
 412                                 min (tmp_realm_times, KRB5_KDB_EXPIRATION)));
 413     } else {
 414         enc_tkt_reply.times.renew_till = 0;
 415     }
 416
 417     /*
 418      * Set authtime to be the same as header_ticket's
 419      */
 420     enc_tkt_reply.times.authtime = header_ticket->enc_part2->times.authtime;
 421
 422     /*
 423      * Propagate the preauthentication flags through to the returned ticket.
 424      */
 425     if (isflagset(header_ticket->enc_part2->flags, TKT_FLG_PRE_AUTH))
 426         setflag(enc_tkt_reply.flags, TKT_FLG_PRE_AUTH);
 427
 428     if (isflagset(header_ticket->enc_part2->flags, TKT_FLG_HW_AUTH))
 429         setflag(enc_tkt_reply.flags, TKT_FLG_HW_AUTH);
 430
 431     /* starttime is optional, and treated as authtime if not present.
 432        so we can nuke it if it matches */
 433     if (enc_tkt_reply.times.starttime == enc_tkt_reply.times.authtime)
 434         enc_tkt_reply.times.starttime = 0;
 435
 436     /* assemble any authorization data */
 437     if (request->authorization_data.ciphertext.data) {
 438         krb5_data scratch;
 439
 440         scratch.length = request->authorization_data.ciphertext.length;
 441         if (!(scratch.data =
 442               malloc(request->authorization_data.ciphertext.length))) {
 443             status = "AUTH_NOMEM";
 444             errcode = ENOMEM;
 445             goto cleanup;
 446         }
 447
 448         if ((errcode = krb5_c_decrypt(kdc_context,
 449                                       header_ticket->enc_part2->session,
 450                                       KRB5_KEYUSAGE_TGS_REQ_AD_SESSKEY,
 451                                       0, &request->authorization_data,
 452                                       &scratch))) {
 453             status = "AUTH_ENCRYPT_FAIL";
 454             free(scratch.data);
 455             goto cleanup;
 456         }
 457
 458         /* scratch now has the authorization data, so we decode it */
 459         errcode = decode_krb5_authdata(&scratch, &(request->unenc_authdata));
 460         free(scratch.data);
 461         if (errcode) {
 462             status = "AUTH_DECODE";
 463             goto cleanup;
 464         }
 465
 466         if ((errcode =
 467              concat_authorization_data(request->unenc_authdata,
 468                                        header_ticket->enc_part2->authorization_data,
 469                                        &enc_tkt_reply.authorization_data))) {
 470             status = "CONCAT_AUTH";
 471             goto cleanup;
 472         }
 473     } else
 474         enc_tkt_reply.authorization_data =
 475             header_ticket->enc_part2->authorization_data;
 476
 477     enc_tkt_reply.session = &session_key;
 478     enc_tkt_reply.client = header_ticket->enc_part2->client;
 479     enc_tkt_reply.transited.tr_type = KRB5_DOMAIN_X500_COMPRESS;
 480     enc_tkt_reply.transited.tr_contents = empty_string; /* equivalent of "" */
 481
 482     /*
 483      * Only add the realm of the presented tgt to the transited list if
 484      * it is different than the local realm (cross-realm) and it is different
 485      * than the realm of the client (since the realm of the client is already
 486      * implicitly part of the transited list and should not be explicitly
 487      * listed).
 488      */
 489
 490     /* realm compare is like strcmp, but knows how to deal with these args */
 491     if (realm_compare(header_ticket->server, tgs_server) ||
 492         realm_compare(header_ticket->server, enc_tkt_reply.client)) {
 493         /* tgt issued by local realm or issued by realm of client */
 494         enc_tkt_reply.transited = header_ticket->enc_part2->transited;
 495     } else {
 496         /* tgt issued by some other realm and not the realm of the client */
 497         /* assemble new transited field into allocated storage */
 498         if (header_ticket->enc_part2->transited.tr_type !=
 499             KRB5_DOMAIN_X500_COMPRESS) {
 500             status = "BAD_TRTYPE";
 501             errcode = KRB5KDC_ERR_TRTYPE_NOSUPP;
 502             goto cleanup;
 503         }
 504         enc_tkt_transited.tr_type = KRB5_DOMAIN_X500_COMPRESS;
 505         enc_tkt_transited.magic = 0;
 506         enc_tkt_transited.tr_contents.magic = 0;
 507         enc_tkt_transited.tr_contents.data = 0;
 508         enc_tkt_transited.tr_contents.length = 0;
 509         enc_tkt_reply.transited = enc_tkt_transited;
 510         if ((errcode =
 511              add_to_transited(&header_ticket->enc_part2->transited.tr_contents,
 512                               &enc_tkt_reply.transited.tr_contents,
 513                               header_ticket->server,
 514                               enc_tkt_reply.client,
 515                               request->server))) {
 516             status = "ADD_TR_FAIL";
 517             goto cleanup;
 518         }
 519         newtransited = 1;
 520     }
 521     if (!isflagset (request->kdc_options, KDC_OPT_DISABLE_TRANSITED_CHECK)) {
 522         unsigned int tlen;
 523         char *tdots;
 524
 525         errcode = krb5_check_transited_list (kdc_context,
 526                                              &enc_tkt_reply.transited.tr_contents,
 527                                              krb5_princ_realm (kdc_context, header_ticket->enc_part2->client),
 528                                              krb5_princ_realm (kdc_context, request->server));
 529         tlen = enc_tkt_reply.transited.tr_contents.length;
 530         tdots = tlen > 125 ? "..." : "";
 531         tlen = tlen > 125 ? 125 : tlen;
 532
 533         if (errcode == 0) {
 534             setflag (enc_tkt_reply.flags, TKT_FLG_TRANSIT_POLICY_CHECKED);
 535         } else if (errcode == KRB5KRB_AP_ERR_ILL_CR_TKT)
 536             krb5_klog_syslog (LOG_INFO,
 537                               "bad realm transit path from '%s' to '%s' "
 538                               "via '%.*s%s'",
 539                               cname ? cname : "<unknown client>",
 540                               sname ? sname : "<unknown server>",
 541                               tlen,
 542                               enc_tkt_reply.transited.tr_contents.data,
 543                               tdots);
 544         else {
 545             const char *emsg = krb5_get_error_message(kdc_context, errcode);
 546             krb5_klog_syslog (LOG_ERR,
 547                               "unexpected error checking transit from "
 548                               "'%s' to '%s' via '%.*s%s': %s",
 549                               cname ? cname : "<unknown client>",
 550                               sname ? sname : "<unknown server>",
 551                               tlen,
 552                               enc_tkt_reply.transited.tr_contents.data,
 553                               tdots, emsg);
 554             krb5_free_error_message(kdc_context, emsg);
 555         }
 556     } else
 557         krb5_klog_syslog (LOG_INFO, "not checking transit path");
 558     if (reject_bad_transit
 559         && !isflagset (enc_tkt_reply.flags, TKT_FLG_TRANSIT_POLICY_CHECKED)) {
 560         errcode = KRB5KDC_ERR_POLICY;
 561         status = "BAD_TRANSIT";
 562         goto cleanup;
 563     }
 564
 565     ticket_reply.enc_part2 = &enc_tkt_reply;
 566
 567     /*
 568      * If we are doing user-to-user authentication, then make sure
 569      * that the client for the second ticket matches the request
 570      * server, and then encrypt the ticket using the session key of
 571      * the second ticket.
 572      */
 573     if (isflagset(request->kdc_options, KDC_OPT_ENC_TKT_IN_SKEY)) {
 574         /*
 575          * Make sure the client for the second ticket matches
 576          * requested server.
 577          */
 578         krb5_enc_tkt_part *t2enc = request->second_ticket[st_idx]->enc_part2;
 579         krb5_principal client2 = t2enc->client;
 580         if (!krb5_principal_compare(kdc_context, request->server, client2)) {
 581                 if ((errcode = krb5_unparse_name(kdc_context, client2, &tmp)))
 582                         tmp = 0;
 583                 if (tmp != NULL)
 584                     limit_string(tmp);
 585                 audit_krb5kdc_tgs_req_2ndtktmm(
 586                         (struct in_addr *)from->address->contents,
 587                         (in_port_t)from->port,
 588                         0, cname, sname);
 589                 krb5_klog_syslog(LOG_INFO,
 590                                  "TGS_REQ %s: 2ND_TKT_MISMATCH: "
 591                                  "authtime %d, %s for %s, 2nd tkt client %s",
 592                                  fromstring, authtime,
 593                                  cname ? cname : "<unknown client>",
 594                                  sname ? sname : "<unknown server>",
 595                                  tmp ? tmp : "<unknown>");
 596                 errcode = KRB5KDC_ERR_SERVER_NOMATCH;
 597                 goto cleanup;
 598         }
 599
 600         ticket_reply.enc_part.kvno = 0;
 601         ticket_reply.enc_part.enctype = t2enc->session->enctype;
 602         if ((errcode = krb5_encrypt_tkt_part(kdc_context, t2enc->session,
 603                                              &ticket_reply))) {
 604             status = "2ND_TKT_ENCRYPT";
 605             goto cleanup;
 606         }
 607         st_idx++;
 608     } else {
 609         /*
 610          * Find the server key
 611          */
 612         if ((errcode = krb5_dbe_find_enctype(kdc_context, &server,
 613                                              -1, /* ignore keytype */
 614                                              -1, /* Ignore salttype */
 615                                              0,         /* Get highest kvno */
 616                                              &server_key))) {
 617             status = "FINDING_SERVER_KEY";
 618             goto cleanup;
 619         }
 620         /* convert server.key into a real key (it may be encrypted
 621          *        in the database) */
 622         if ((errcode = krb5_dbekd_decrypt_key_data(kdc_context,
 623                                                    &master_keyblock,
 624                                                    server_key, &encrypting_key,
 625                                                    NULL))) {
 626             status = "DECRYPT_SERVER_KEY";
 627             goto cleanup;
 628         }
 629         errcode = krb5_encrypt_tkt_part(kdc_context, &encrypting_key,
 630                                         &ticket_reply);
 631         krb5_free_keyblock_contents(kdc_context, &encrypting_key);
 632         if (errcode) {
 633             status = "TKT_ENCRYPT";
 634             goto cleanup;
 635         }
 636         ticket_reply.enc_part.kvno = server_key->key_data_kvno;
 637     }
 638
 639     /* Start assembling the response */
 640     reply.msg_type = KRB5_TGS_REP;
 641     reply.padata = 0;           /* always */
 642     reply.client = header_ticket->enc_part2->client;
 643     reply.enc_part.kvno = 0;            /* We are using the session key */
 644     reply.ticket = &ticket_reply;
 645
 646     reply_encpart.session = &session_key;
 647     reply_encpart.nonce = request->nonce;
 648
 649     /* copy the time fields EXCEPT for authtime; its location
 650        is used for ktime */
 651     reply_encpart.times = enc_tkt_reply.times;
 652     reply_encpart.times.authtime = header_ticket->enc_part2->times.authtime;
 653
 654     /* starttime is optional, and treated as authtime if not present.
 655        so we can nuke it if it matches */
 656     if (enc_tkt_reply.times.starttime == enc_tkt_reply.times.authtime)
 657         enc_tkt_reply.times.starttime = 0;
 658
 659     nolrentry.lr_type = KRB5_LRQ_NONE;
 660     nolrentry.value = 0;
 661     nolrarray[0] = &nolrentry;
 662     nolrarray[1] = 0;
 663     reply_encpart.last_req = nolrarray; /* not available for TGS reqs */
 664     reply_encpart.key_exp = 0;          /* ditto */
 665     reply_encpart.flags = enc_tkt_reply.flags;
 666     reply_encpart.server = ticket_reply.server;
 667
 668     /* use the session key in the ticket, unless there's a subsession key
 669        in the AP_REQ */
 670
 671     reply.enc_part.enctype = subkey ? subkey->enctype :
 672                     header_ticket->enc_part2->session->enctype;
 673     errcode = krb5_encode_kdc_rep(kdc_context, KRB5_TGS_REP, &reply_encpart,
 674                                   subkey ? 1 : 0,
 675                                   subkey ? subkey :
 676                                   header_ticket->enc_part2->session,
 677                                   &reply, response);
 678     if (errcode) {
 679         status = "ENCODE_KDC_REP";
 680     } else {
 681         status = "ISSUE";
 682     }
 683
 684     if (ticket_reply.enc_part.ciphertext.data) {
 685      memset(ticket_reply.enc_part.ciphertext.data, 0,
 686            ticket_reply.enc_part.ciphertext.length);
 687     free(ticket_reply.enc_part.ciphertext.data);
 688         ticket_reply.enc_part.ciphertext.data = NULL;
 689     }
 690     /* these parts are left on as a courtesy from krb5_encode_kdc_rep so we
 691        can use them in raw form if needed.  But, we don't... */
 692     if (reply.enc_part.ciphertext.data) {
 693      memset(reply.enc_part.ciphertext.data, 0,
 694            reply.enc_part.ciphertext.length);
 695     free(reply.enc_part.ciphertext.data);
 696         reply.enc_part.ciphertext.data = NULL;
 697     }
 698
 699 cleanup:
 700     if (status) {
 701         const char * emsg = NULL;
 702             audit_krb5kdc_tgs_req((struct in_addr *)from->address->contents,
 703                                 (in_port_t)from->port, 0,
 704                                 cname ? cname : "<unknown client>",
 705                                 sname ? sname : "<unknown client>",
 706                                 errcode);
 707         if (!errcode)
 708             rep_etypes2str(rep_etypestr, sizeof(rep_etypestr), &reply);
 709         if (errcode)
 710             emsg = krb5_get_error_message (kdc_context, errcode);
 711         krb5_klog_syslog(LOG_INFO,
 712                          "TGS_REQ (%s) %s: %s: authtime %d, "
 713                          "%s%s %s for %s%s%s",
 714                          ktypestr,
 715                          fromstring, status, authtime,
 716                          !errcode ? rep_etypestr : "",
 717                          !errcode ? "," : "",
 718                          cname ? cname : "<unknown client>",
 719                          sname ? sname : "<unknown server>",
 720                          errcode ? ", " : "",
 721                          errcode ? emsg : "");
 722         if (errcode)
 723             krb5_free_error_message (kdc_context, emsg);
 724     }
 725
 726     if (errcode) {
 727         int got_err = 0;
 728         if (status == 0) {
 729             status = krb5_get_error_message (kdc_context, errcode);
 730             got_err = 1;
 731         }
 732         errcode -= ERROR_TABLE_BASE_krb5;
 733         if (errcode < 0 || errcode > 128)
 734             errcode = KRB_ERR_GENERIC;
 735
 736         retval = prepare_error_tgs(request, header_ticket, errcode,
 737                                    fromstring, response, status);
 738         if (got_err) {
 739             krb5_free_error_message (kdc_context, status);
 740             status = 0;
 741         }
 742     }
 743
 744     if (header_ticket)
 745         krb5_free_ticket(kdc_context, header_ticket);
 746     if (request)
 747         krb5_free_kdc_req(kdc_context, request);
 748     free(cname);
 749     free(sname);
 750     if (nprincs)
 751         krb5_db_free_principal(kdc_context, &server, 1);
 752     if (session_key.contents)
 753         krb5_free_keyblock_contents(kdc_context, &session_key);
 754     if (newtransited)
 755         free(enc_tkt_reply.transited.tr_contents.data);
 756
 757     return retval;
 758 }
 759
 760 static krb5_error_code
 761 prepare_error_tgs (krb5_kdc_req *request, krb5_ticket *ticket, int error,
 762                    const char *ident, krb5_data **response, const char *status)
 763 {
 764     krb5_error errpkt;
 765     krb5_error_code retval;
 766     krb5_data *scratch;
 767
 768     errpkt.ctime = request->nonce;
 769     errpkt.cusec = 0;
 770
 771     if ((retval = krb5_us_timeofday(kdc_context, &errpkt.stime,
 772                                     &errpkt.susec)))
 773         return(retval);
 774     errpkt.error = error;
 775     errpkt.server = request->server;
 776     if (ticket && ticket->enc_part2)
 777         errpkt.client = ticket->enc_part2->client;
 778     else
 779         errpkt.client = 0;
 780     errpkt.text.length = strlen(status) + 1;
 781     if (!(errpkt.text.data = malloc(errpkt.text.length)))
 782         return ENOMEM;
 783     (void) strcpy(errpkt.text.data, status);
 784
 785     if (!(scratch = (krb5_data *)malloc(sizeof(*scratch)))) {
 786         free(errpkt.text.data);
 787         return ENOMEM;
 788     }
 789     errpkt.e_data.length = 0;
 790     errpkt.e_data.data = 0;
 791
 792     retval = krb5_mk_error(kdc_context, &errpkt, scratch);
 793     free(errpkt.text.data);
 794     if (retval)
 795         free(scratch);
 796     else
 797         *response = scratch;
 798
 799     return retval;
 800 }
 801
 802 /*
 803  * The request seems to be for a ticket-granting service somewhere else,
 804  * but we don't have a ticket for the final TGS.  Try to give the requestor
 805  * some intermediate realm.
 806  */
 807 static void
 808 find_alternate_tgs(krb5_kdc_req *request, krb5_db_entry *server,
 809                    krb5_boolean *more, int *nprincs,
 810                    const krb5_fulladdr *from, char *cname)
 811 {
 812     krb5_error_code retval;
 813     krb5_principal *plist, *pl2;
 814     krb5_data tmp;
 815
 816     *nprincs = 0;
 817     *more = FALSE;
 818
 819     /*
 820      * Call to krb5_princ_component is normally not safe but is so
 821      * here only because find_alternate_tgs() is only called from
 822      * somewhere that has already checked the number of components in
 823      * the principal.
 824      */
 825     if ((retval = krb5_walk_realm_tree(kdc_context,
 826                       krb5_princ_realm(kdc_context, request->server),
 827                       krb5_princ_component(kdc_context, request->server, 1),
 828                                       &plist, KRB5_REALM_BRANCH_CHAR)))
 829         return;
 830
 831     /* move to the end */
 832     for (pl2 = plist; *pl2; pl2++);
 833
 834     /* the first entry in this array is for krbtgt/local@local, so we
 835        ignore it */
 836     while (--pl2 > plist) {
 837         *nprincs = 1;
 838         tmp = *krb5_princ_realm(kdc_context, *pl2);
 839         krb5_princ_set_realm(kdc_context, *pl2,
 840                              krb5_princ_realm(kdc_context, tgs_server));
 841         retval = krb5_db_get_principal(kdc_context, *pl2, server, nprincs, more);
 842         krb5_princ_set_realm(kdc_context, *pl2, &tmp);
 843         if (retval) {
 844             *nprincs = 0;
 845             *more = FALSE;
 846             krb5_free_realm_tree(kdc_context, plist);
 847             return;
 848         }
 849         if (*more) {
 850             krb5_db_free_principal(kdc_context, server, *nprincs);
 851             continue;
 852         } else if (*nprincs == 1) {
 853             /* Found it! */
 854             krb5_principal tmpprinc;
 855             char *sname;
 856
 857             tmp = *krb5_princ_realm(kdc_context, *pl2);
 858             krb5_princ_set_realm(kdc_context, *pl2,
 859                                  krb5_princ_realm(kdc_context, tgs_server));
 860             if ((retval = krb5_copy_principal(kdc_context, *pl2, &tmpprinc))) {
 861                 krb5_db_free_principal(kdc_context, server, *nprincs);
 862                 krb5_princ_set_realm(kdc_context, *pl2, &tmp);
 863                 continue;
 864             }
 865             krb5_princ_set_realm(kdc_context, *pl2, &tmp);
 866
 867             krb5_free_principal(kdc_context, request->server);
 868             request->server = tmpprinc;
 869             if (krb5_unparse_name(kdc_context, request->server, &sname)) {
 870
 871                 audit_krb5kdc_tgs_req_alt_tgt(
 872                         (struct in_addr *)from->address->contents,
 873                         (in_port_t)from->port,
 874                         0, cname, "<unparseable>", 0);
 875                 krb5_klog_syslog(LOG_INFO,
 876                        "TGS_REQ: issuing alternate <un-unparseable> TGT");
 877             } else {
 878                 limit_string(sname);
 879                 audit_krb5kdc_tgs_req_alt_tgt(
 880                         (struct in_addr *)from->address->contents,
 881                         (in_port_t)from->port,
 882                         0, cname, sname, 0);
 883                 krb5_klog_syslog(LOG_INFO,
 884                        "TGS_REQ: issuing TGT %s", sname);
 885                 free(sname);
 886             }
 887             return;
 888         }
 889         krb5_db_free_principal(kdc_context, server, *nprincs);
 890         continue;
 891     }
 892
 893     *nprincs = 0;
 894     *more = FALSE;
 895     krb5_free_realm_tree(kdc_context, plist);
 896     return;
 897 }