source4/heimdal/lib/krb5/rd_req.c

   1 /*
   2  * Copyright (c) 1997 - 2001, 2003 - 2005 Kungliga Tekniska Högskolan
   3  * (Royal Institute of Technology, Stockholm, Sweden).
   4  * All rights reserved.
   5  *
   6  * Redistribution and use in source and binary forms, with or without
   7  * modification, are permitted provided that the following conditions
   8  * are met:
   9  *
  10  * 1. Redistributions of source code must retain the above copyright
  11  *    notice, this list of conditions and the following disclaimer.
  12  *
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in the
  15  *    documentation and/or other materials provided with the distribution.
  16  *
  17  * 3. Neither the name of the Institute nor the names of its contributors
  18  *    may be used to endorse or promote products derived from this software
  19  *    without specific prior written permission.
  20  *
  21  * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
  22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
  25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  31  * SUCH DAMAGE.
  32  */
  33
  34 #include <krb5_locl.h>
  35
  36 RCSID("$Id: rd_req.c,v 1.63 2006/04/10 10:14:44 lha Exp $");
  37
  38 static krb5_error_code
  39 decrypt_tkt_enc_part (krb5_context context,
  40                       krb5_keyblock *key,
  41                       EncryptedData *enc_part,
  42                       EncTicketPart *decr_part)
  43 {
  44     krb5_error_code ret;
  45     krb5_data plain;
  46     size_t len;
  47     krb5_crypto crypto;
  48
  49     ret = krb5_crypto_init(context, key, 0, &crypto);
  50     if (ret)
  51         return ret;
  52     ret = krb5_decrypt_EncryptedData (context,
  53                                       crypto,
  54                                       KRB5_KU_TICKET,
  55                                       enc_part,
  56                                       &plain);
  57     krb5_crypto_destroy(context, crypto);
  58     if (ret)
  59         return ret;
  60
  61     ret = krb5_decode_EncTicketPart(context, plain.data, plain.length,
  62                                     decr_part, &len);
  63     krb5_data_free (&plain);
  64     return ret;
  65 }
  66
  67 static krb5_error_code
  68 decrypt_authenticator (krb5_context context,
  69                        EncryptionKey *key,
  70                        EncryptedData *enc_part,
  71                        Authenticator *authenticator,
  72                        krb5_key_usage usage)
  73 {
  74     krb5_error_code ret;
  75     krb5_data plain;
  76     size_t len;
  77     krb5_crypto crypto;
  78
  79     ret = krb5_crypto_init(context, key, 0, &crypto);
  80     if (ret)
  81         return ret;
  82     ret = krb5_decrypt_EncryptedData (context,
  83                                       crypto,
  84                                       usage /* KRB5_KU_AP_REQ_AUTH */,
  85                                       enc_part,
  86                                       &plain);
  87     /* for backwards compatibility, also try the old usage */
  88     if (ret && usage == KRB5_KU_TGS_REQ_AUTH)
  89         ret = krb5_decrypt_EncryptedData (context,
  90                                           crypto,
  91                                           KRB5_KU_AP_REQ_AUTH,
  92                                           enc_part,
  93                                           &plain);
  94     krb5_crypto_destroy(context, crypto);
  95     if (ret)
  96         return ret;
  97
  98     ret = krb5_decode_Authenticator(context, plain.data, plain.length,
  99                                     authenticator, &len);
 100     krb5_data_free (&plain);
 101     return ret;
 102 }
 103
 104 krb5_error_code KRB5_LIB_FUNCTION
 105 krb5_decode_ap_req(krb5_context context,
 106                    const krb5_data *inbuf,
 107                    krb5_ap_req *ap_req)
 108 {
 109     krb5_error_code ret;
 110     size_t len;
 111     ret = decode_AP_REQ(inbuf->data, inbuf->length, ap_req, &len);
 112     if (ret)
 113         return ret;
 114     if (ap_req->pvno != 5){
 115         free_AP_REQ(ap_req);
 116         krb5_clear_error_string (context);
 117         return KRB5KRB_AP_ERR_BADVERSION;
 118     }
 119     if (ap_req->msg_type != krb_ap_req){
 120         free_AP_REQ(ap_req);
 121         krb5_clear_error_string (context);
 122         return KRB5KRB_AP_ERR_MSG_TYPE;
 123     }
 124     if (ap_req->ticket.tkt_vno != 5){
 125         free_AP_REQ(ap_req);
 126         krb5_clear_error_string (context);
 127         return KRB5KRB_AP_ERR_BADVERSION;
 128     }
 129     return 0;
 130 }
 131
 132 static krb5_error_code
 133 check_transited(krb5_context context, Ticket *ticket, EncTicketPart *enc)
 134 {
 135     char **realms;
 136     int num_realms;
 137     krb5_error_code ret;
 138
 139     /*
 140      * Windows 2000 and 2003 uses this inside their TGT so its normaly
 141      * not seen by others, however, samba4 joined with a Windows AD as
 142      * a Domain Controller gets exposed to this.
 143      */
 144     if(enc->transited.tr_type == 0 && enc->transited.contents.length == 0)
 145         return 0;
 146
 147     if(enc->transited.tr_type != DOMAIN_X500_COMPRESS)
 148         return KRB5KDC_ERR_TRTYPE_NOSUPP;
 149
 150     if(enc->transited.contents.length == 0)
 151         return 0;
 152
 153     ret = krb5_domain_x500_decode(context, enc->transited.contents,
 154                                   &realms, &num_realms,
 155                                   enc->crealm,
 156                                   ticket->realm);
 157     if(ret)
 158         return ret;
 159     ret = krb5_check_transited(context, enc->crealm,
 160                                ticket->realm,
 161                                realms, num_realms, NULL);
 162     free(realms);
 163     return ret;
 164 }
 165
 166 static krb5_error_code
 167 find_etypelist(krb5_context context,
 168                krb5_auth_context auth_context,
 169                EtypeList *etypes)
 170 {
 171     krb5_error_code ret;
 172     krb5_authdata *ad;
 173     krb5_authdata adIfRelevant;
 174     unsigned i;
 175
 176     adIfRelevant.len = 0;
 177
 178     etypes->len = 0;
 179     etypes->val = NULL;
 180
 181     ad = auth_context->authenticator->authorization_data;
 182     if (ad == NULL)
 183         return 0;
 184
 185     for (i = 0; i < ad->len; i++) {
 186         if (ad->val[i].ad_type == KRB5_AUTHDATA_IF_RELEVANT) {
 187             ret = decode_AD_IF_RELEVANT(ad->val[i].ad_data.data,
 188                                         ad->val[i].ad_data.length,
 189                                         &adIfRelevant,
 190                                         NULL);
 191             if (ret)
 192                 return ret;
 193
 194             if (adIfRelevant.len == 1 &&
 195                 adIfRelevant.val[0].ad_type ==
 196                         KRB5_AUTHDATA_GSS_API_ETYPE_NEGOTIATION) {
 197                 break;
 198             }
 199             free_AD_IF_RELEVANT(&adIfRelevant);
 200             adIfRelevant.len = 0;
 201         }
 202     }
 203
 204     if (adIfRelevant.len == 0)
 205         return 0;
 206
 207     ret = decode_EtypeList(adIfRelevant.val[0].ad_data.data,
 208                            adIfRelevant.val[0].ad_data.length,
 209                            etypes,
 210                            NULL);
 211
 212     free_AD_IF_RELEVANT(&adIfRelevant);
 213
 214     return ret;
 215 }
 216
 217 krb5_error_code KRB5_LIB_FUNCTION
 218 krb5_decrypt_ticket(krb5_context context,
 219                     Ticket *ticket,
 220                     krb5_keyblock *key,
 221                     EncTicketPart *out,
 222                     krb5_flags flags)
 223 {
 224     EncTicketPart t;
 225     krb5_error_code ret;
 226     ret = decrypt_tkt_enc_part (context, key, &ticket->enc_part, &t);
 227     if (ret)
 228         return ret;
 229
 230     {
 231         krb5_timestamp now;
 232         time_t start = t.authtime;
 233
 234         krb5_timeofday (context, &now);
 235         if(t.starttime)
 236             start = *t.starttime;
 237         if(start - now > context->max_skew
 238            || (t.flags.invalid
 239                && !(flags & KRB5_VERIFY_AP_REQ_IGNORE_INVALID))) {
 240             free_EncTicketPart(&t);
 241             krb5_clear_error_string (context);
 242             return KRB5KRB_AP_ERR_TKT_NYV;
 243         }
 244         if(now - t.endtime > context->max_skew) {
 245             free_EncTicketPart(&t);
 246             krb5_clear_error_string (context);
 247             return KRB5KRB_AP_ERR_TKT_EXPIRED;
 248         }
 249
 250         if(!t.flags.transited_policy_checked) {
 251             ret = check_transited(context, ticket, &t);
 252             if(ret) {
 253                 free_EncTicketPart(&t);
 254                 return ret;
 255             }
 256         }
 257     }
 258
 259     if(out)
 260         *out = t;
 261     else
 262         free_EncTicketPart(&t);
 263     return 0;
 264 }
 265
 266 krb5_error_code KRB5_LIB_FUNCTION
 267 krb5_verify_authenticator_checksum(krb5_context context,
 268                                    krb5_auth_context ac,
 269                                    void *data,
 270                                    size_t len)
 271 {
 272     krb5_error_code ret;
 273     krb5_keyblock *key;
 274     krb5_authenticator authenticator;
 275     krb5_crypto crypto;
 276
 277     ret = krb5_auth_con_getauthenticator (context,
 278                                       ac,
 279                                       &authenticator);
 280     if(ret)
 281         return ret;
 282     if(authenticator->cksum == NULL) {
 283         krb5_free_authenticator(context, &authenticator);
 284         return -17;
 285     }
 286     ret = krb5_auth_con_getkey(context, ac, &key);
 287     if(ret) {
 288         krb5_free_authenticator(context, &authenticator);
 289         return ret;
 290     }
 291     ret = krb5_crypto_init(context, key, 0, &crypto);
 292     if(ret)
 293         goto out;
 294     ret = krb5_verify_checksum (context,
 295                                 crypto,
 296                                 KRB5_KU_AP_REQ_AUTH_CKSUM,
 297                                 data,
 298                                 len,
 299                                 authenticator->cksum);
 300     krb5_crypto_destroy(context, crypto);
 301 out:
 302     krb5_free_authenticator(context, &authenticator);
 303     krb5_free_keyblock(context, key);
 304     return ret;
 305 }
 306
 307
 308 krb5_error_code KRB5_LIB_FUNCTION
 309 krb5_verify_ap_req(krb5_context context,
 310                    krb5_auth_context *auth_context,
 311                    krb5_ap_req *ap_req,
 312                    krb5_const_principal server,
 313                    krb5_keyblock *keyblock,
 314                    krb5_flags flags,
 315                    krb5_flags *ap_req_options,
 316                    krb5_ticket **ticket)
 317 {
 318     return krb5_verify_ap_req2 (context,
 319                                 auth_context,
 320                                 ap_req,
 321                                 server,
 322                                 keyblock,
 323                                 flags,
 324                                 ap_req_options,
 325                                 ticket,
 326                                 KRB5_KU_AP_REQ_AUTH);
 327 }
 328
 329 krb5_error_code KRB5_LIB_FUNCTION
 330 krb5_verify_ap_req2(krb5_context context,
 331                     krb5_auth_context *auth_context,
 332                     krb5_ap_req *ap_req,
 333                     krb5_const_principal server,
 334                     krb5_keyblock *keyblock,
 335                     krb5_flags flags,
 336                     krb5_flags *ap_req_options,
 337                     krb5_ticket **ticket,
 338                     krb5_key_usage usage)
 339 {
 340     krb5_ticket *t;
 341     krb5_auth_context ac;
 342     krb5_error_code ret;
 343     EtypeList etypes;
 344
 345     if (ticket)
 346         *ticket = NULL;
 347
 348     if (auth_context && *auth_context) {
 349         ac = *auth_context;
 350     } else {
 351         ret = krb5_auth_con_init (context, &ac);
 352         if (ret)
 353             return ret;
 354     }
 355
 356     t = calloc(1, sizeof(*t));
 357     if (t == NULL) {
 358         ret = ENOMEM;
 359         krb5_clear_error_string (context);
 360         goto out;
 361     }
 362
 363     if (ap_req->ap_options.use_session_key && ac->keyblock){
 364         ret = krb5_decrypt_ticket(context, &ap_req->ticket,
 365                                   ac->keyblock,
 366                                   &t->ticket,
 367                                   flags);
 368         krb5_free_keyblock(context, ac->keyblock);
 369         ac->keyblock = NULL;
 370     }else
 371         ret = krb5_decrypt_ticket(context, &ap_req->ticket,
 372                                   keyblock,
 373                                   &t->ticket,
 374                                   flags);
 375
 376     if(ret)
 377         goto out;
 378
 379     ret = _krb5_principalname2krb5_principal(context,
 380                                              &t->server, ap_req->ticket.sname,
 381                                              ap_req->ticket.realm);
 382     if (ret) goto out;
 383     ret = _krb5_principalname2krb5_principal(context,
 384                                              &t->client, t->ticket.cname,
 385                                              t->ticket.crealm);
 386     if (ret) goto out;
 387
 388     /* save key */
 389
 390     ret = krb5_copy_keyblock(context, &t->ticket.key, &ac->keyblock);
 391     if (ret) goto out;
 392
 393     ret = decrypt_authenticator (context,
 394                                  &t->ticket.key,
 395                                  &ap_req->authenticator,
 396                                  ac->authenticator,
 397                                  usage);
 398     if (ret)
 399         goto out;
 400
 401     {
 402         krb5_principal p1, p2;
 403         krb5_boolean res;
 404
 405         _krb5_principalname2krb5_principal(context, &p1,
 406                                            ac->authenticator->cname,
 407                                            ac->authenticator->crealm);
 408         _krb5_principalname2krb5_principal(context, &p2,
 409                                            t->ticket.cname,
 410                                            t->ticket.crealm);
 411         res = krb5_principal_compare (context, p1, p2);
 412         krb5_free_principal (context, p1);
 413         krb5_free_principal (context, p2);
 414         if (!res) {
 415             ret = KRB5KRB_AP_ERR_BADMATCH;
 416             krb5_clear_error_string (context);
 417             goto out;
 418         }
 419     }
 420
 421     /* check addresses */
 422
 423     if (t->ticket.caddr
 424         && ac->remote_address
 425         && !krb5_address_search (context,
 426                                  ac->remote_address,
 427                                  t->ticket.caddr)) {
 428         ret = KRB5KRB_AP_ERR_BADADDR;
 429         krb5_clear_error_string (context);
 430         goto out;
 431     }
 432
 433     /* check timestamp in authenticator */
 434     {
 435         krb5_timestamp now;
 436
 437         krb5_timeofday (context, &now);
 438
 439         if (abs(ac->authenticator->ctime - now) > context->max_skew) {
 440             ret = KRB5KRB_AP_ERR_SKEW;
 441             krb5_clear_error_string (context);
 442             goto out;
 443         }
 444     }
 445
 446     if (ac->authenticator->seq_number)
 447         krb5_auth_con_setremoteseqnumber(context, ac,
 448                                          *ac->authenticator->seq_number);
 449
 450     /* XXX - Xor sequence numbers */
 451
 452     if (ac->authenticator->subkey) {
 453         ret = krb5_auth_con_setremotesubkey(context, ac,
 454                                             ac->authenticator->subkey);
 455         if (ret)
 456             goto out;
 457     }
 458
 459     ret = find_etypelist(context, ac, &etypes);
 460     if (ret)
 461         goto out;
 462
 463     ac->keytype = ETYPE_NULL;
 464
 465     if (etypes.val) {
 466         int i;
 467
 468         for (i = 0; i < etypes.len; i++) {
 469             if (krb5_enctype_valid(context, etypes.val[i]) == 0) {
 470                 ac->keytype = etypes.val[i];
 471                 break;
 472             }
 473         }
 474     }
 475
 476     if (ap_req_options) {
 477         *ap_req_options = 0;
 478         if (ac->keytype != ETYPE_NULL)
 479             *ap_req_options |= AP_OPTS_USE_SUBKEY;
 480         if (ap_req->ap_options.use_session_key)
 481             *ap_req_options |= AP_OPTS_USE_SESSION_KEY;
 482         if (ap_req->ap_options.mutual_required)
 483             *ap_req_options |= AP_OPTS_MUTUAL_REQUIRED;
 484     }
 485
 486     if(ticket)
 487         *ticket = t;
 488     else
 489         krb5_free_ticket (context, t);
 490     if (auth_context) {
 491         if (*auth_context == NULL)
 492             *auth_context = ac;
 493     } else
 494         krb5_auth_con_free (context, ac);
 495     free_EtypeList(&etypes);
 496     return 0;
 497  out:
 498     if (t)
 499         krb5_free_ticket (context, t);
 500     if (auth_context == NULL || *auth_context == NULL)
 501         krb5_auth_con_free (context, ac);
 502     return ret;
 503 }
 504
 505
 506 krb5_error_code KRB5_LIB_FUNCTION
 507 krb5_rd_req_with_keyblock(krb5_context context,
 508                           krb5_auth_context *auth_context,
 509                           const krb5_data *inbuf,
 510                           krb5_const_principal server,
 511                           krb5_keyblock *keyblock,
 512                           krb5_flags *ap_req_options,
 513                           krb5_ticket **ticket)
 514 {
 515     krb5_error_code ret;
 516     krb5_ap_req ap_req;
 517
 518     if (*auth_context == NULL) {
 519         ret = krb5_auth_con_init(context, auth_context);
 520         if (ret)
 521             return ret;
 522     }
 523
 524     ret = krb5_decode_ap_req(context, inbuf, &ap_req);
 525     if(ret)
 526         return ret;
 527
 528     ret = krb5_verify_ap_req(context,
 529                              auth_context,
 530                              &ap_req,
 531                              server,
 532                              keyblock,
 533                              0,
 534                              ap_req_options,
 535                              ticket);
 536
 537     free_AP_REQ(&ap_req);
 538     return ret;
 539 }
 540
 541 static krb5_error_code
 542 get_key_from_keytab(krb5_context context,
 543                     krb5_auth_context *auth_context,
 544                     krb5_ap_req *ap_req,
 545                     krb5_const_principal server,
 546                     krb5_keytab keytab,
 547                     krb5_keyblock **out_key)
 548 {
 549     krb5_keytab_entry entry;
 550     krb5_error_code ret;
 551     int kvno;
 552     krb5_keytab real_keytab;
 553
 554     if(keytab == NULL)
 555         krb5_kt_default(context, &real_keytab);
 556     else
 557         real_keytab = keytab;
 558
 559     if (ap_req->ticket.enc_part.kvno)
 560         kvno = *ap_req->ticket.enc_part.kvno;
 561     else
 562         kvno = 0;
 563
 564     ret = krb5_kt_get_entry (context,
 565                              real_keytab,
 566                              server,
 567                              kvno,
 568                              ap_req->ticket.enc_part.etype,
 569                              &entry);
 570     if(ret)
 571         goto out;
 572     ret = krb5_copy_keyblock(context, &entry.keyblock, out_key);
 573     krb5_kt_free_entry (context, &entry);
 574 out:
 575     if(keytab == NULL)
 576         krb5_kt_close(context, real_keytab);
 577
 578     return ret;
 579 }
 580
 581 krb5_error_code KRB5_LIB_FUNCTION
 582 krb5_rd_req_return_keyblock(krb5_context context,
 583                             krb5_auth_context *auth_context,
 584                             const krb5_data *inbuf,
 585                             krb5_const_principal server,
 586                             krb5_keytab keytab,
 587                             krb5_flags *ap_req_options,
 588                             krb5_ticket **ticket,
 589                             krb5_keyblock **return_keyblock)
 590 {
 591     krb5_error_code ret;
 592     krb5_ap_req ap_req;
 593     krb5_keyblock *keyblock = NULL;
 594     krb5_principal service = NULL;
 595
 596     if (return_keyblock)
 597         *return_keyblock = NULL;
 598
 599     if (*auth_context == NULL) {
 600         ret = krb5_auth_con_init(context, auth_context);
 601         if (ret)
 602             return ret;
 603     }
 604
 605     ret = krb5_decode_ap_req(context, inbuf, &ap_req);
 606     if(ret)
 607         return ret;
 608
 609     if(server == NULL){
 610         _krb5_principalname2krb5_principal(context, &service,
 611                                            ap_req.ticket.sname,
 612                                            ap_req.ticket.realm);
 613         server = service;
 614     }
 615     if (ap_req.ap_options.use_session_key &&
 616         (*auth_context)->keyblock == NULL) {
 617         krb5_set_error_string(context, "krb5_rd_req: user to user auth "
 618                               "without session key given");
 619         ret = KRB5KRB_AP_ERR_NOKEY;
 620         goto out;
 621     }
 622
 623     if((*auth_context)->keyblock == NULL){
 624         ret = get_key_from_keytab(context,
 625                                   auth_context,
 626                                   &ap_req,
 627                                   server,
 628                                   keytab,
 629                                   &keyblock);
 630         if(ret)
 631             goto out;
 632     } else {
 633         ret = krb5_copy_keyblock(context,
 634                                  (*auth_context)->keyblock,
 635                                  &keyblock);
 636         if (ret)
 637             goto out;
 638     }
 639
 640     ret = krb5_verify_ap_req(context,
 641                              auth_context,
 642                              &ap_req,
 643                              server,
 644                              keyblock,
 645                              0,
 646                              ap_req_options,
 647                              ticket);
 648
 649     if (ret == 0 && return_keyblock)
 650         *return_keyblock = keyblock;
 651     else
 652         krb5_free_keyblock(context, keyblock);
 653
 654 out:
 655     free_AP_REQ(&ap_req);
 656     if(service)
 657         krb5_free_principal(context, service);
 658     return ret;
 659 }
 660
 661 krb5_error_code KRB5_LIB_FUNCTION
 662 krb5_rd_req(krb5_context context,
 663             krb5_auth_context *auth_context,
 664             const krb5_data *inbuf,
 665             krb5_const_principal server,
 666             krb5_keytab keytab,
 667             krb5_flags *ap_req_options,
 668             krb5_ticket **ticket)
 669 {
 670     return krb5_rd_req_return_keyblock(context,
 671                                        auth_context,
 672                                        inbuf,
 673                                        server,
 674                                        keytab,
 675                                        ap_req_options,
 676                                        ticket,
 677                                        NULL);
 678
 679 }
 680