source4/heimdal/lib/krb5/rd_req.c

   1 /*
   2  * Copyright (c) 1997 - 2001, 2003 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 1.57 2005/01/08 20:41:17 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     if(enc->transited.tr_type != DOMAIN_X500_COMPRESS)
 140         return KRB5KDC_ERR_TRTYPE_NOSUPP;
 141
 142     if(enc->transited.contents.length == 0)
 143         return 0;
 144
 145     ret = krb5_domain_x500_decode(context, enc->transited.contents,
 146                                   &realms, &num_realms,
 147                                   enc->crealm,
 148                                   ticket->realm);
 149     if(ret)
 150         return ret;
 151     ret = krb5_check_transited(context, enc->crealm,
 152                                ticket->realm,
 153                                realms, num_realms, NULL);
 154     free(realms);
 155     return ret;
 156 }
 157
 158 static krb5_error_code
 159 find_etypelist(krb5_context context,
 160                krb5_auth_context auth_context,
 161                EtypeList *etypes)
 162 {
 163     krb5_error_code ret;
 164     krb5_authdata *ad;
 165     krb5_authdata adIfRelevant;
 166     unsigned i;
 167
 168     adIfRelevant.len = 0;
 169
 170     etypes->len = 0;
 171     etypes->val = NULL;
 172
 173     ad = auth_context->authenticator->authorization_data;
 174     if (ad == NULL)
 175         return 0;
 176
 177     for (i = 0; i < ad->len; i++) {
 178         if (ad->val[i].ad_type == KRB5_AUTHDATA_IF_RELEVANT) {
 179             ret = decode_AD_IF_RELEVANT(ad->val[i].ad_data.data,
 180                                         ad->val[i].ad_data.length,
 181                                         &adIfRelevant,
 182                                         NULL);
 183             if (ret)
 184                 return ret;
 185
 186             if (adIfRelevant.len == 1 &&
 187                 adIfRelevant.val[0].ad_type ==
 188                         KRB5_AUTHDATA_GSS_API_ETYPE_NEGOTIATION) {
 189                 break;
 190             }
 191             free_AD_IF_RELEVANT(&adIfRelevant);
 192             adIfRelevant.len = 0;
 193         }
 194     }
 195
 196     if (adIfRelevant.len == 0)
 197         return 0;
 198
 199     ret = decode_EtypeList(adIfRelevant.val[0].ad_data.data,
 200                            adIfRelevant.val[0].ad_data.length,
 201                            etypes,
 202                            NULL);
 203
 204     free_AD_IF_RELEVANT(&adIfRelevant);
 205
 206     return ret;
 207 }
 208
 209 krb5_error_code KRB5_LIB_FUNCTION
 210 krb5_decrypt_ticket(krb5_context context,
 211                     Ticket *ticket,
 212                     krb5_keyblock *key,
 213                     EncTicketPart *out,
 214                     krb5_flags flags)
 215 {
 216     EncTicketPart t;
 217     krb5_error_code ret;
 218     ret = decrypt_tkt_enc_part (context, key, &ticket->enc_part, &t);
 219     if (ret)
 220         return ret;
 221
 222     {
 223         krb5_timestamp now;
 224         time_t start = t.authtime;
 225
 226         krb5_timeofday (context, &now);
 227         if(t.starttime)
 228             start = *t.starttime;
 229         if(start - now > context->max_skew
 230            || (t.flags.invalid
 231                && !(flags & KRB5_VERIFY_AP_REQ_IGNORE_INVALID))) {
 232             free_EncTicketPart(&t);
 233             krb5_clear_error_string (context);
 234             return KRB5KRB_AP_ERR_TKT_NYV;
 235         }
 236         if(now - t.endtime > context->max_skew) {
 237             free_EncTicketPart(&t);
 238             krb5_clear_error_string (context);
 239             return KRB5KRB_AP_ERR_TKT_EXPIRED;
 240         }
 241
 242         if(!t.flags.transited_policy_checked) {
 243             ret = check_transited(context, ticket, &t);
 244             if(ret) {
 245                 free_EncTicketPart(&t);
 246                 return ret;
 247             }
 248         }
 249     }
 250
 251     if(out)
 252         *out = t;
 253     else
 254         free_EncTicketPart(&t);
 255     return 0;
 256 }
 257
 258 krb5_error_code KRB5_LIB_FUNCTION
 259 krb5_verify_authenticator_checksum(krb5_context context,
 260                                    krb5_auth_context ac,
 261                                    void *data,
 262                                    size_t len)
 263 {
 264     krb5_error_code ret;
 265     krb5_keyblock *key;
 266     krb5_authenticator authenticator;
 267     krb5_crypto crypto;
 268
 269     ret = krb5_auth_con_getauthenticator (context,
 270                                       ac,
 271                                       &authenticator);
 272     if(ret)
 273         return ret;
 274     if(authenticator->cksum == NULL)
 275         return -17;
 276     ret = krb5_auth_con_getkey(context, ac, &key);
 277     if(ret) {
 278         krb5_free_authenticator(context, &authenticator);
 279         return ret;
 280     }
 281     ret = krb5_crypto_init(context, key, 0, &crypto);
 282     if(ret)
 283         goto out;
 284     ret = krb5_verify_checksum (context,
 285                                 crypto,
 286                                 KRB5_KU_AP_REQ_AUTH_CKSUM,
 287                                 data,
 288                                 len,
 289                                 authenticator->cksum);
 290     krb5_crypto_destroy(context, crypto);
 291 out:
 292     krb5_free_authenticator(context, &authenticator);
 293     krb5_free_keyblock(context, key);
 294     return ret;
 295 }
 296
 297
 298 krb5_error_code KRB5_LIB_FUNCTION
 299 krb5_verify_ap_req(krb5_context context,
 300                    krb5_auth_context *auth_context,
 301                    krb5_ap_req *ap_req,
 302                    krb5_const_principal server,
 303                    krb5_keyblock *keyblock,
 304                    krb5_flags flags,
 305                    krb5_flags *ap_req_options,
 306                    krb5_ticket **ticket)
 307 {
 308     return krb5_verify_ap_req2 (context,
 309                                 auth_context,
 310                                 ap_req,
 311                                 server,
 312                                 keyblock,
 313                                 flags,
 314                                 ap_req_options,
 315                                 ticket,
 316                                 KRB5_KU_AP_REQ_AUTH);
 317 }
 318
 319 krb5_error_code KRB5_LIB_FUNCTION
 320 krb5_verify_ap_req2(krb5_context context,
 321                     krb5_auth_context *auth_context,
 322                     krb5_ap_req *ap_req,
 323                     krb5_const_principal server,
 324                     krb5_keyblock *keyblock,
 325                     krb5_flags flags,
 326                     krb5_flags *ap_req_options,
 327                     krb5_ticket **ticket,
 328                     krb5_key_usage usage)
 329 {
 330     krb5_ticket *t;
 331     krb5_auth_context ac;
 332     krb5_error_code ret;
 333     EtypeList etypes;
 334
 335     if (auth_context && *auth_context) {
 336         ac = *auth_context;
 337     } else {
 338         ret = krb5_auth_con_init (context, &ac);
 339         if (ret)
 340             return ret;
 341     }
 342
 343     t = malloc(sizeof(*t));
 344     if (t == NULL) {
 345         ret = ENOMEM;
 346         krb5_clear_error_string (context);
 347         goto out;
 348     }
 349     memset(t, 0, sizeof(*t));
 350
 351     if (ap_req->ap_options.use_session_key && ac->keyblock){
 352         ret = krb5_decrypt_ticket(context, &ap_req->ticket,
 353                                   ac->keyblock,
 354                                   &t->ticket,
 355                                   flags);
 356         krb5_free_keyblock(context, ac->keyblock);
 357         ac->keyblock = NULL;
 358     }else
 359         ret = krb5_decrypt_ticket(context, &ap_req->ticket,
 360                                   keyblock,
 361                                   &t->ticket,
 362                                   flags);
 363
 364     if(ret)
 365         goto out;
 366
 367     _krb5_principalname2krb5_principal(&t->server, ap_req->ticket.sname,
 368                                        ap_req->ticket.realm);
 369     _krb5_principalname2krb5_principal(&t->client, t->ticket.cname,
 370                                        t->ticket.crealm);
 371
 372     /* save key */
 373
 374     krb5_copy_keyblock(context, &t->ticket.key, &ac->keyblock);
 375
 376     ret = decrypt_authenticator (context,
 377                                  &t->ticket.key,
 378                                  &ap_req->authenticator,
 379                                  ac->authenticator,
 380                                  usage);
 381     if (ret)
 382         goto out;
 383
 384     {
 385         krb5_principal p1, p2;
 386         krb5_boolean res;
 387
 388         _krb5_principalname2krb5_principal(&p1,
 389                                            ac->authenticator->cname,
 390                                            ac->authenticator->crealm);
 391         _krb5_principalname2krb5_principal(&p2,
 392                                            t->ticket.cname,
 393                                            t->ticket.crealm);
 394         res = krb5_principal_compare (context, p1, p2);
 395         krb5_free_principal (context, p1);
 396         krb5_free_principal (context, p2);
 397         if (!res) {
 398             ret = KRB5KRB_AP_ERR_BADMATCH;
 399             krb5_clear_error_string (context);
 400             goto out;
 401         }
 402     }
 403
 404     /* check addresses */
 405
 406     if (t->ticket.caddr
 407         && ac->remote_address
 408         && !krb5_address_search (context,
 409                                  ac->remote_address,
 410                                  t->ticket.caddr)) {
 411         ret = KRB5KRB_AP_ERR_BADADDR;
 412         krb5_clear_error_string (context);
 413         goto out;
 414     }
 415
 416     if (ac->authenticator->seq_number)
 417         krb5_auth_con_setremoteseqnumber(context, ac,
 418                                          *ac->authenticator->seq_number);
 419
 420     /* XXX - Xor sequence numbers */
 421
 422     if (ac->authenticator->subkey) {
 423         ret = krb5_auth_con_setremotesubkey(context, ac,
 424                                             ac->authenticator->subkey);
 425         if (ret)
 426             goto out;
 427     }
 428
 429     ret = find_etypelist(context, ac, &etypes);
 430     if (ret)
 431         goto out;
 432
 433     ac->keytype = ETYPE_NULL;
 434
 435     if (etypes.val) {
 436         int i;
 437
 438         for (i = 0; i < etypes.len; i++) {
 439             if (krb5_enctype_valid(context, etypes.val[i]) == 0) {
 440                 ac->keytype = etypes.val[i];
 441                 break;
 442             }
 443         }
 444     }
 445
 446     if (ap_req_options) {
 447         *ap_req_options = 0;
 448         if (ac->keytype != ETYPE_NULL)
 449             *ap_req_options |= AP_OPTS_USE_SUBKEY;
 450         if (ap_req->ap_options.use_session_key)
 451             *ap_req_options |= AP_OPTS_USE_SESSION_KEY;
 452         if (ap_req->ap_options.mutual_required)
 453             *ap_req_options |= AP_OPTS_MUTUAL_REQUIRED;
 454     }
 455
 456     if(ticket)
 457         *ticket = t;
 458     else
 459         krb5_free_ticket (context, t);
 460     if (auth_context) {
 461         if (*auth_context == NULL)
 462             *auth_context = ac;
 463     } else
 464         krb5_auth_con_free (context, ac);
 465     free_EtypeList(&etypes);
 466     return 0;
 467  out:
 468     if (t)
 469         krb5_free_ticket (context, t);
 470     if (auth_context == NULL || *auth_context == NULL)
 471         krb5_auth_con_free (context, ac);
 472     return ret;
 473 }
 474
 475
 476 krb5_error_code KRB5_LIB_FUNCTION
 477 krb5_rd_req_with_keyblock(krb5_context context,
 478                           krb5_auth_context *auth_context,
 479                           const krb5_data *inbuf,
 480                           krb5_const_principal server,
 481                           krb5_keyblock *keyblock,
 482                           krb5_flags *ap_req_options,
 483                           krb5_ticket **ticket)
 484 {
 485     krb5_error_code ret;
 486     krb5_ap_req ap_req;
 487
 488     if (*auth_context == NULL) {
 489         ret = krb5_auth_con_init(context, auth_context);
 490         if (ret)
 491             return ret;
 492     }
 493
 494     ret = krb5_decode_ap_req(context, inbuf, &ap_req);
 495     if(ret)
 496         return ret;
 497
 498     ret = krb5_verify_ap_req(context,
 499                              auth_context,
 500                              &ap_req,
 501                              server,
 502                              keyblock,
 503                              0,
 504                              ap_req_options,
 505                              ticket);
 506
 507     free_AP_REQ(&ap_req);
 508     return ret;
 509 }
 510
 511 static krb5_error_code
 512 get_key_from_keytab(krb5_context context,
 513                     krb5_auth_context *auth_context,
 514                     krb5_ap_req *ap_req,
 515                     krb5_const_principal server,
 516                     krb5_keytab keytab,
 517                     krb5_keyblock **out_key)
 518 {
 519     krb5_keytab_entry entry;
 520     krb5_error_code ret;
 521     int kvno;
 522     krb5_keytab real_keytab;
 523
 524     if(keytab == NULL)
 525         krb5_kt_default(context, &real_keytab);
 526     else
 527         real_keytab = keytab;
 528
 529     if (ap_req->ticket.enc_part.kvno)
 530         kvno = *ap_req->ticket.enc_part.kvno;
 531     else
 532         kvno = 0;
 533
 534     ret = krb5_kt_get_entry (context,
 535                              real_keytab,
 536                              server,
 537                              kvno,
 538                              ap_req->ticket.enc_part.etype,
 539                              &entry);
 540     if(ret)
 541         goto out;
 542     ret = krb5_copy_keyblock(context, &entry.keyblock, out_key);
 543     krb5_kt_free_entry (context, &entry);
 544 out:
 545     if(keytab == NULL)
 546         krb5_kt_close(context, real_keytab);
 547
 548     return ret;
 549 }
 550
 551 krb5_error_code KRB5_LIB_FUNCTION
 552 krb5_rd_req_return_keyblock(krb5_context context,
 553                             krb5_auth_context *auth_context,
 554                             const krb5_data *inbuf,
 555                             krb5_const_principal server,
 556                             krb5_keytab keytab,
 557                             krb5_flags *ap_req_options,
 558                             krb5_ticket **ticket,
 559                             krb5_keyblock **keyblock)
 560 {
 561     krb5_error_code ret;
 562     krb5_ap_req ap_req;
 563     krb5_principal service = NULL;
 564
 565     if (*auth_context == NULL) {
 566         ret = krb5_auth_con_init(context, auth_context);
 567         if (ret)
 568             return ret;
 569     }
 570
 571     ret = krb5_decode_ap_req(context, inbuf, &ap_req);
 572     if(ret)
 573         return ret;
 574
 575     if(server == NULL){
 576         _krb5_principalname2krb5_principal(&service,
 577                                            ap_req.ticket.sname,
 578                                            ap_req.ticket.realm);
 579         server = service;
 580     }
 581     if (ap_req.ap_options.use_session_key &&
 582         (*auth_context)->keyblock == NULL) {
 583         krb5_set_error_string(context, "krb5_rd_req: user to user auth "
 584                               "without session key given");
 585         ret = KRB5KRB_AP_ERR_NOKEY;
 586         goto out;
 587     }
 588
 589     if((*auth_context)->keyblock == NULL){
 590         ret = get_key_from_keytab(context,
 591                                   auth_context,
 592                                   &ap_req,
 593                                   server,
 594                                   keytab,
 595                                   keyblock);
 596         if(ret)
 597             goto out;
 598     } else {
 599         ret = krb5_copy_keyblock(context,
 600                                  (*auth_context)->keyblock,
 601                                  keyblock);
 602         if (ret)
 603             goto out;
 604     }
 605
 606     ret = krb5_verify_ap_req(context,
 607                              auth_context,
 608                              &ap_req,
 609                              server,
 610                              *keyblock,
 611                              0,
 612                              ap_req_options,
 613                              ticket);
 614
 615 out:
 616     free_AP_REQ(&ap_req);
 617     if(service)
 618         krb5_free_principal(context, service);
 619     if (ret)
 620         krb5_free_keyblock(context, *keyblock);
 621
 622     return ret;
 623 }
 624
 625 krb5_error_code KRB5_LIB_FUNCTION
 626 krb5_rd_req(krb5_context context,
 627             krb5_auth_context *auth_context,
 628             const krb5_data *inbuf,
 629             krb5_const_principal server,
 630             krb5_keytab keytab,
 631             krb5_flags *ap_req_options,
 632             krb5_ticket **ticket)
 633 {
 634     krb5_error_code ret;
 635     krb5_keyblock *keyblock;
 636
 637     ret = krb5_rd_req_return_keyblock(context,
 638                                       auth_context,
 639                                       inbuf,
 640                                       server,
 641                                       keytab,
 642                                       ap_req_options,
 643                                       ticket,
 644                                       &keyblock);
 645
 646     krb5_free_keyblock(context, keyblock);
 647     return ret;
 648 }
 649