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 1.58 2005/08/27 05:48:57 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     /* Windows w2k and w2k3 uses this */
 140     if(enc->transited.tr_type == 0 && enc->transited.contents.length == 0)
 141         return 0;
 142
 143     if(enc->transited.tr_type != DOMAIN_X500_COMPRESS)
 144         return KRB5KDC_ERR_TRTYPE_NOSUPP;
 145
 146     if(enc->transited.contents.length == 0)
 147         return 0;
 148
 149     ret = krb5_domain_x500_decode(context, enc->transited.contents,
 150                                   &realms, &num_realms,
 151                                   enc->crealm,
 152                                   ticket->realm);
 153     if(ret)
 154         return ret;
 155     ret = krb5_check_transited(context, enc->crealm,
 156                                ticket->realm,
 157                                realms, num_realms, NULL);
 158     free(realms);
 159     return ret;
 160 }
 161
 162 static krb5_error_code
 163 find_etypelist(krb5_context context,
 164                krb5_auth_context auth_context,
 165                EtypeList *etypes)
 166 {
 167     krb5_error_code ret;
 168     krb5_authdata *ad;
 169     krb5_authdata adIfRelevant;
 170     unsigned i;
 171
 172     adIfRelevant.len = 0;
 173
 174     etypes->len = 0;
 175     etypes->val = NULL;
 176
 177     ad = auth_context->authenticator->authorization_data;
 178     if (ad == NULL)
 179         return 0;
 180
 181     for (i = 0; i < ad->len; i++) {
 182         if (ad->val[i].ad_type == KRB5_AUTHDATA_IF_RELEVANT) {
 183             ret = decode_AD_IF_RELEVANT(ad->val[i].ad_data.data,
 184                                         ad->val[i].ad_data.length,
 185                                         &adIfRelevant,
 186                                         NULL);
 187             if (ret)
 188                 return ret;
 189
 190             if (adIfRelevant.len == 1 &&
 191                 adIfRelevant.val[0].ad_type ==
 192                         KRB5_AUTHDATA_GSS_API_ETYPE_NEGOTIATION) {
 193                 break;
 194             }
 195             free_AD_IF_RELEVANT(&adIfRelevant);
 196             adIfRelevant.len = 0;
 197         }
 198     }
 199
 200     if (adIfRelevant.len == 0)
 201         return 0;
 202
 203     ret = decode_EtypeList(adIfRelevant.val[0].ad_data.data,
 204                            adIfRelevant.val[0].ad_data.length,
 205                            etypes,
 206                            NULL);
 207
 208     free_AD_IF_RELEVANT(&adIfRelevant);
 209
 210     return ret;
 211 }
 212
 213 krb5_error_code KRB5_LIB_FUNCTION
 214 krb5_decrypt_ticket(krb5_context context,
 215                     Ticket *ticket,
 216                     krb5_keyblock *key,
 217                     EncTicketPart *out,
 218                     krb5_flags flags)
 219 {
 220     EncTicketPart t;
 221     krb5_error_code ret;
 222     ret = decrypt_tkt_enc_part (context, key, &ticket->enc_part, &t);
 223     if (ret)
 224         return ret;
 225
 226     {
 227         krb5_timestamp now;
 228         time_t start = t.authtime;
 229
 230         krb5_timeofday (context, &now);
 231         if(t.starttime)
 232             start = *t.starttime;
 233         if(start - now > context->max_skew
 234            || (t.flags.invalid
 235                && !(flags & KRB5_VERIFY_AP_REQ_IGNORE_INVALID))) {
 236             free_EncTicketPart(&t);
 237             krb5_clear_error_string (context);
 238             return KRB5KRB_AP_ERR_TKT_NYV;
 239         }
 240         if(now - t.endtime > context->max_skew) {
 241             free_EncTicketPart(&t);
 242             krb5_clear_error_string (context);
 243             return KRB5KRB_AP_ERR_TKT_EXPIRED;
 244         }
 245
 246         if(!t.flags.transited_policy_checked) {
 247             ret = check_transited(context, ticket, &t);
 248             if(ret) {
 249                 free_EncTicketPart(&t);
 250                 return ret;
 251             }
 252         }
 253     }
 254
 255     if(out)
 256         *out = t;
 257     else
 258         free_EncTicketPart(&t);
 259     return 0;
 260 }
 261
 262 krb5_error_code KRB5_LIB_FUNCTION
 263 krb5_verify_authenticator_checksum(krb5_context context,
 264                                    krb5_auth_context ac,
 265                                    void *data,
 266                                    size_t len)
 267 {
 268     krb5_error_code ret;
 269     krb5_keyblock *key;
 270     krb5_authenticator authenticator;
 271     krb5_crypto crypto;
 272
 273     ret = krb5_auth_con_getauthenticator (context,
 274                                       ac,
 275                                       &authenticator);
 276     if(ret)
 277         return ret;
 278     if(authenticator->cksum == NULL)
 279         return -17;
 280     ret = krb5_auth_con_getkey(context, ac, &key);
 281     if(ret) {
 282         krb5_free_authenticator(context, &authenticator);
 283         return ret;
 284     }
 285     ret = krb5_crypto_init(context, key, 0, &crypto);
 286     if(ret)
 287         goto out;
 288     ret = krb5_verify_checksum (context,
 289                                 crypto,
 290                                 KRB5_KU_AP_REQ_AUTH_CKSUM,
 291                                 data,
 292                                 len,
 293                                 authenticator->cksum);
 294     krb5_crypto_destroy(context, crypto);
 295 out:
 296     krb5_free_authenticator(context, &authenticator);
 297     krb5_free_keyblock(context, key);
 298     return ret;
 299 }
 300
 301
 302 krb5_error_code KRB5_LIB_FUNCTION
 303 krb5_verify_ap_req(krb5_context context,
 304                    krb5_auth_context *auth_context,
 305                    krb5_ap_req *ap_req,
 306                    krb5_const_principal server,
 307                    krb5_keyblock *keyblock,
 308                    krb5_flags flags,
 309                    krb5_flags *ap_req_options,
 310                    krb5_ticket **ticket)
 311 {
 312     return krb5_verify_ap_req2 (context,
 313                                 auth_context,
 314                                 ap_req,
 315                                 server,
 316                                 keyblock,
 317                                 flags,
 318                                 ap_req_options,
 319                                 ticket,
 320                                 KRB5_KU_AP_REQ_AUTH);
 321 }
 322
 323 krb5_error_code KRB5_LIB_FUNCTION
 324 krb5_verify_ap_req2(krb5_context context,
 325                     krb5_auth_context *auth_context,
 326                     krb5_ap_req *ap_req,
 327                     krb5_const_principal server,
 328                     krb5_keyblock *keyblock,
 329                     krb5_flags flags,
 330                     krb5_flags *ap_req_options,
 331                     krb5_ticket **ticket,
 332                     krb5_key_usage usage)
 333 {
 334     krb5_ticket *t;
 335     krb5_auth_context ac;
 336     krb5_error_code ret;
 337     EtypeList etypes;
 338
 339     if (auth_context && *auth_context) {
 340         ac = *auth_context;
 341     } else {
 342         ret = krb5_auth_con_init (context, &ac);
 343         if (ret)
 344             return ret;
 345     }
 346
 347     t = malloc(sizeof(*t));
 348     if (t == NULL) {
 349         ret = ENOMEM;
 350         krb5_clear_error_string (context);
 351         goto out;
 352     }
 353     memset(t, 0, sizeof(*t));
 354
 355     if (ap_req->ap_options.use_session_key && ac->keyblock){
 356         ret = krb5_decrypt_ticket(context, &ap_req->ticket,
 357                                   ac->keyblock,
 358                                   &t->ticket,
 359                                   flags);
 360         krb5_free_keyblock(context, ac->keyblock);
 361         ac->keyblock = NULL;
 362     }else
 363         ret = krb5_decrypt_ticket(context, &ap_req->ticket,
 364                                   keyblock,
 365                                   &t->ticket,
 366                                   flags);
 367
 368     if(ret)
 369         goto out;
 370
 371     _krb5_principalname2krb5_principal(&t->server, ap_req->ticket.sname,
 372                                        ap_req->ticket.realm);
 373     _krb5_principalname2krb5_principal(&t->client, t->ticket.cname,
 374                                        t->ticket.crealm);
 375
 376     /* save key */
 377
 378     krb5_copy_keyblock(context, &t->ticket.key, &ac->keyblock);
 379
 380     ret = decrypt_authenticator (context,
 381                                  &t->ticket.key,
 382                                  &ap_req->authenticator,
 383                                  ac->authenticator,
 384                                  usage);
 385     if (ret)
 386         goto out;
 387
 388     {
 389         krb5_principal p1, p2;
 390         krb5_boolean res;
 391
 392         _krb5_principalname2krb5_principal(&p1,
 393                                            ac->authenticator->cname,
 394                                            ac->authenticator->crealm);
 395         _krb5_principalname2krb5_principal(&p2,
 396                                            t->ticket.cname,
 397                                            t->ticket.crealm);
 398         res = krb5_principal_compare (context, p1, p2);
 399         krb5_free_principal (context, p1);
 400         krb5_free_principal (context, p2);
 401         if (!res) {
 402             ret = KRB5KRB_AP_ERR_BADMATCH;
 403             krb5_clear_error_string (context);
 404             goto out;
 405         }
 406     }
 407
 408     /* check addresses */
 409
 410     if (t->ticket.caddr
 411         && ac->remote_address
 412         && !krb5_address_search (context,
 413                                  ac->remote_address,
 414                                  t->ticket.caddr)) {
 415         ret = KRB5KRB_AP_ERR_BADADDR;
 416         krb5_clear_error_string (context);
 417         goto out;
 418     }
 419
 420     if (ac->authenticator->seq_number)
 421         krb5_auth_con_setremoteseqnumber(context, ac,
 422                                          *ac->authenticator->seq_number);
 423
 424     /* XXX - Xor sequence numbers */
 425
 426     if (ac->authenticator->subkey) {
 427         ret = krb5_auth_con_setremotesubkey(context, ac,
 428                                             ac->authenticator->subkey);
 429         if (ret)
 430             goto out;
 431     }
 432
 433     ret = find_etypelist(context, ac, &etypes);
 434     if (ret)
 435         goto out;
 436
 437     ac->keytype = ETYPE_NULL;
 438
 439     if (etypes.val) {
 440         int i;
 441
 442         for (i = 0; i < etypes.len; i++) {
 443             if (krb5_enctype_valid(context, etypes.val[i]) == 0) {
 444                 ac->keytype = etypes.val[i];
 445                 break;
 446             }
 447         }
 448     }
 449
 450     if (ap_req_options) {
 451         *ap_req_options = 0;
 452         if (ac->keytype != ETYPE_NULL)
 453             *ap_req_options |= AP_OPTS_USE_SUBKEY;
 454         if (ap_req->ap_options.use_session_key)
 455             *ap_req_options |= AP_OPTS_USE_SESSION_KEY;
 456         if (ap_req->ap_options.mutual_required)
 457             *ap_req_options |= AP_OPTS_MUTUAL_REQUIRED;
 458     }
 459
 460     if(ticket)
 461         *ticket = t;
 462     else
 463         krb5_free_ticket (context, t);
 464     if (auth_context) {
 465         if (*auth_context == NULL)
 466             *auth_context = ac;
 467     } else
 468         krb5_auth_con_free (context, ac);
 469     free_EtypeList(&etypes);
 470     return 0;
 471  out:
 472     if (t)
 473         krb5_free_ticket (context, t);
 474     if (auth_context == NULL || *auth_context == NULL)
 475         krb5_auth_con_free (context, ac);
 476     return ret;
 477 }
 478
 479
 480 krb5_error_code KRB5_LIB_FUNCTION
 481 krb5_rd_req_with_keyblock(krb5_context context,
 482                           krb5_auth_context *auth_context,
 483                           const krb5_data *inbuf,
 484                           krb5_const_principal server,
 485                           krb5_keyblock *keyblock,
 486                           krb5_flags *ap_req_options,
 487                           krb5_ticket **ticket)
 488 {
 489     krb5_error_code ret;
 490     krb5_ap_req ap_req;
 491
 492     if (*auth_context == NULL) {
 493         ret = krb5_auth_con_init(context, auth_context);
 494         if (ret)
 495             return ret;
 496     }
 497
 498     ret = krb5_decode_ap_req(context, inbuf, &ap_req);
 499     if(ret)
 500         return ret;
 501
 502     ret = krb5_verify_ap_req(context,
 503                              auth_context,
 504                              &ap_req,
 505                              server,
 506                              keyblock,
 507                              0,
 508                              ap_req_options,
 509                              ticket);
 510
 511     free_AP_REQ(&ap_req);
 512     return ret;
 513 }
 514
 515 static krb5_error_code
 516 get_key_from_keytab(krb5_context context,
 517                     krb5_auth_context *auth_context,
 518                     krb5_ap_req *ap_req,
 519                     krb5_const_principal server,
 520                     krb5_keytab keytab,
 521                     krb5_keyblock **out_key)
 522 {
 523     krb5_keytab_entry entry;
 524     krb5_error_code ret;
 525     int kvno;
 526     krb5_keytab real_keytab;
 527
 528     if(keytab == NULL)
 529         krb5_kt_default(context, &real_keytab);
 530     else
 531         real_keytab = keytab;
 532
 533     if (ap_req->ticket.enc_part.kvno)
 534         kvno = *ap_req->ticket.enc_part.kvno;
 535     else
 536         kvno = 0;
 537
 538     ret = krb5_kt_get_entry (context,
 539                              real_keytab,
 540                              server,
 541                              kvno,
 542                              ap_req->ticket.enc_part.etype,
 543                              &entry);
 544     if(ret)
 545         goto out;
 546     ret = krb5_copy_keyblock(context, &entry.keyblock, out_key);
 547     krb5_kt_free_entry (context, &entry);
 548 out:
 549     if(keytab == NULL)
 550         krb5_kt_close(context, real_keytab);
 551
 552     return ret;
 553 }
 554
 555 krb5_error_code KRB5_LIB_FUNCTION
 556 krb5_rd_req_return_keyblock(krb5_context context,
 557                             krb5_auth_context *auth_context,
 558                             const krb5_data *inbuf,
 559                             krb5_const_principal server,
 560                             krb5_keytab keytab,
 561                             krb5_flags *ap_req_options,
 562                             krb5_ticket **ticket,
 563                             krb5_keyblock **return_keyblock)
 564 {
 565     krb5_error_code ret;
 566     krb5_ap_req ap_req;
 567     krb5_keyblock *keyblock = NULL;
 568     krb5_principal service = NULL;
 569
 570     if (return_keyblock)
 571         *return_keyblock = NULL;
 572
 573     if (*auth_context == NULL) {
 574         ret = krb5_auth_con_init(context, auth_context);
 575         if (ret)
 576             return ret;
 577     }
 578
 579     ret = krb5_decode_ap_req(context, inbuf, &ap_req);
 580     if(ret)
 581         return ret;
 582
 583     if(server == NULL){
 584         _krb5_principalname2krb5_principal(&service,
 585                                            ap_req.ticket.sname,
 586                                            ap_req.ticket.realm);
 587         server = service;
 588     }
 589     if (ap_req.ap_options.use_session_key &&
 590         (*auth_context)->keyblock == NULL) {
 591         krb5_set_error_string(context, "krb5_rd_req: user to user auth "
 592                               "without session key given");
 593         ret = KRB5KRB_AP_ERR_NOKEY;
 594         goto out;
 595     }
 596
 597     if((*auth_context)->keyblock == NULL){
 598         ret = get_key_from_keytab(context,
 599                                   auth_context,
 600                                   &ap_req,
 601                                   server,
 602                                   keytab,
 603                                   &keyblock);
 604         if(ret)
 605             goto out;
 606     } else {
 607         ret = krb5_copy_keyblock(context,
 608                                  (*auth_context)->keyblock,
 609                                  &keyblock);
 610         if (ret)
 611             goto out;
 612     }
 613
 614     ret = krb5_verify_ap_req(context,
 615                              auth_context,
 616                              &ap_req,
 617                              server,
 618                              keyblock,
 619                              0,
 620                              ap_req_options,
 621                              ticket);
 622
 623     if (ret == 0 && return_keyblock)
 624         *return_keyblock = keyblock;
 625     else
 626         krb5_free_keyblock(context, keyblock);
 627
 628 out:
 629     free_AP_REQ(&ap_req);
 630     if(service)
 631         krb5_free_principal(context, service);
 632     return ret;
 633 }
 634
 635 krb5_error_code KRB5_LIB_FUNCTION
 636 krb5_rd_req(krb5_context context,
 637             krb5_auth_context *auth_context,
 638             const krb5_data *inbuf,
 639             krb5_const_principal server,
 640             krb5_keytab keytab,
 641             krb5_flags *ap_req_options,
 642             krb5_ticket **ticket)
 643 {
 644     return krb5_rd_req_return_keyblock(context,
 645                                        auth_context,
 646                                        inbuf,
 647                                        server,
 648                                        keytab,
 649                                        ap_req_options,
 650                                        ticket,
 651                                        NULL);
 652
 653 }
 654