lib/krb5/rd_req.c

   1
   2 /*
   3  * Copyright (c) 1997 - 2007 Kungliga Tekniska Högskolan
   4  * (Royal Institute of Technology, Stockholm, Sweden).
   5  * All rights reserved.
   6  *
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, are permitted provided that the following conditions
   9  * are met:
  10  *
  11  * 1. Redistributions of source code must retain the above copyright
  12  *    notice, this list of conditions and the following disclaimer.
  13  *
  14  * 2. Redistributions in binary form must reproduce the above copyright
  15  *    notice, this list of conditions and the following disclaimer in the
  16  *    documentation and/or other materials provided with the distribution.
  17  *
  18  * 3. Neither the name of the Institute nor the names of its contributors
  19  *    may be used to endorse or promote products derived from this software
  20  *    without specific prior written permission.
  21  *
  22  * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
  23  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  24  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  25  * ARE DISCLAIMED.  IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
  26  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  27  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  28  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  29  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  30  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  31  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  32  * SUCH DAMAGE.
  33  */
  34
  35 #include "krb5_locl.h"
  36
  37 static krb5_error_code
  38 decrypt_tkt_enc_part (krb5_context context,
  39                       krb5_keyblock *key,
  40                       EncryptedData *enc_part,
  41                       EncTicketPart *decr_part)
  42 {
  43     krb5_error_code ret;
  44     krb5_data plain;
  45     size_t len;
  46     krb5_crypto crypto;
  47
  48     ret = krb5_crypto_init(context, key, 0, &crypto);
  49     if (ret)
  50         return ret;
  51     ret = krb5_decrypt_EncryptedData (context,
  52                                       crypto,
  53                                       KRB5_KU_TICKET,
  54                                       enc_part,
  55                                       &plain);
  56     krb5_crypto_destroy(context, crypto);
  57     if (ret)
  58         return ret;
  59
  60     ret = decode_EncTicketPart(plain.data, plain.length, decr_part, &len);
  61     if (ret)
  62         krb5_set_error_message(context, ret,
  63                                N_("Failed to decode encrypted "
  64                                   "ticket part", ""));
  65     krb5_data_free (&plain);
  66     return ret;
  67 }
  68
  69 static krb5_error_code
  70 decrypt_authenticator (krb5_context context,
  71                        EncryptionKey *key,
  72                        EncryptedData *enc_part,
  73                        Authenticator *authenticator,
  74                        krb5_key_usage usage)
  75 {
  76     krb5_error_code ret;
  77     krb5_data plain;
  78     size_t len;
  79     krb5_crypto crypto;
  80
  81     ret = krb5_crypto_init(context, key, 0, &crypto);
  82     if (ret)
  83         return ret;
  84     ret = krb5_decrypt_EncryptedData (context,
  85                                       crypto,
  86                                       usage /* KRB5_KU_AP_REQ_AUTH */,
  87                                       enc_part,
  88                                       &plain);
  89     /* for backwards compatibility, also try the old usage */
  90     if (ret && usage == KRB5_KU_TGS_REQ_AUTH)
  91         ret = krb5_decrypt_EncryptedData (context,
  92                                           crypto,
  93                                           KRB5_KU_AP_REQ_AUTH,
  94                                           enc_part,
  95                                           &plain);
  96     krb5_crypto_destroy(context, crypto);
  97     if (ret)
  98         return ret;
  99
 100     ret = decode_Authenticator(plain.data, plain.length,
 101                                authenticator, &len);
 102     krb5_data_free (&plain);
 103     return ret;
 104 }
 105
 106 KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL
 107 krb5_decode_ap_req(krb5_context context,
 108                    const krb5_data *inbuf,
 109                    krb5_ap_req *ap_req)
 110 {
 111     krb5_error_code ret;
 112     size_t len;
 113     ret = decode_AP_REQ(inbuf->data, inbuf->length, ap_req, &len);
 114     if (ret)
 115         return ret;
 116     if (ap_req->pvno != 5){
 117         free_AP_REQ(ap_req);
 118         krb5_clear_error_message (context);
 119         return KRB5KRB_AP_ERR_BADVERSION;
 120     }
 121     if (ap_req->msg_type != krb_ap_req){
 122         free_AP_REQ(ap_req);
 123         krb5_clear_error_message (context);
 124         return KRB5KRB_AP_ERR_MSG_TYPE;
 125     }
 126     if (ap_req->ticket.tkt_vno != 5){
 127         free_AP_REQ(ap_req);
 128         krb5_clear_error_message (context);
 129         return KRB5KRB_AP_ERR_BADVERSION;
 130     }
 131     return 0;
 132 }
 133
 134 static krb5_error_code
 135 check_transited(krb5_context context, Ticket *ticket, EncTicketPart *enc)
 136 {
 137     char **realms;
 138     unsigned int num_realms, n;
 139     krb5_error_code ret;
 140
 141     /*
 142      * Windows 2000 and 2003 uses this inside their TGT so it's normaly
 143      * not seen by others, however, samba4 joined with a Windows AD as
 144      * a Domain Controller gets exposed to this.
 145      */
 146     if(enc->transited.tr_type == 0 && enc->transited.contents.length == 0)
 147         return 0;
 148
 149     if(enc->transited.tr_type != DOMAIN_X500_COMPRESS)
 150         return KRB5KDC_ERR_TRTYPE_NOSUPP;
 151
 152     if(enc->transited.contents.length == 0)
 153         return 0;
 154
 155     ret = krb5_domain_x500_decode(context, enc->transited.contents,
 156                                   &realms, &num_realms,
 157                                   enc->crealm,
 158                                   ticket->realm);
 159     if(ret)
 160         return ret;
 161     ret = krb5_check_transited(context, enc->crealm,
 162                                ticket->realm,
 163                                realms, num_realms, NULL);
 164     for (n = 0; n < num_realms; n++)
 165         free(realms[n]);
 166     free(realms);
 167     return ret;
 168 }
 169
 170 static krb5_error_code
 171 find_etypelist(krb5_context context,
 172                krb5_auth_context auth_context,
 173                EtypeList *etypes)
 174 {
 175     krb5_error_code ret;
 176     krb5_data data;
 177
 178     ret = _krb5_get_ad(context, auth_context->authenticator->authorization_data, NULL, KRB5_AUTHDATA_GSS_API_ETYPE_NEGOTIATION, &data);
 179     if (ret)
 180         return 0;
 181
 182     ret = decode_EtypeList(data.data, data.length, etypes, NULL);
 183     krb5_data_free(&data);
 184     if (ret)
 185         krb5_clear_error_message(context);
 186
 187     return ret;
 188 }
 189
 190 KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL
 191 krb5_decrypt_ticket(krb5_context context,
 192                     Ticket *ticket,
 193                     krb5_keyblock *key,
 194                     EncTicketPart *out,
 195                     krb5_flags flags)
 196 {
 197     EncTicketPart t;
 198     krb5_error_code ret;
 199     ret = decrypt_tkt_enc_part (context, key, &ticket->enc_part, &t);
 200     if (ret)
 201         return ret;
 202
 203     {
 204         krb5_timestamp now;
 205         time_t start = t.authtime;
 206
 207         krb5_timeofday (context, &now);
 208         if(t.starttime)
 209             start = *t.starttime;
 210         if(start - now > context->max_skew
 211            || (t.flags.invalid
 212                && !(flags & KRB5_VERIFY_AP_REQ_IGNORE_INVALID))) {
 213             free_EncTicketPart(&t);
 214             krb5_clear_error_message (context);
 215             return KRB5KRB_AP_ERR_TKT_NYV;
 216         }
 217         if(now - t.endtime > context->max_skew) {
 218             free_EncTicketPart(&t);
 219             krb5_clear_error_message (context);
 220             return KRB5KRB_AP_ERR_TKT_EXPIRED;
 221         }
 222
 223         if(!t.flags.transited_policy_checked) {
 224             ret = check_transited(context, ticket, &t);
 225             if(ret) {
 226                 free_EncTicketPart(&t);
 227                 return ret;
 228             }
 229         }
 230     }
 231
 232     if(out)
 233         *out = t;
 234     else
 235         free_EncTicketPart(&t);
 236     return 0;
 237 }
 238
 239 KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL
 240 krb5_verify_authenticator_checksum(krb5_context context,
 241                                    krb5_auth_context ac,
 242                                    void *data,
 243                                    size_t len)
 244 {
 245     krb5_error_code ret;
 246     krb5_keyblock *key;
 247     krb5_authenticator authenticator;
 248     krb5_crypto crypto;
 249
 250     ret = krb5_auth_con_getauthenticator (context,
 251                                       ac,
 252                                       &authenticator);
 253     if(ret)
 254         return ret;
 255     if(authenticator->cksum == NULL) {
 256         krb5_free_authenticator(context, &authenticator);
 257         return -17;
 258     }
 259     ret = krb5_auth_con_getkey(context, ac, &key);
 260     if(ret) {
 261         krb5_free_authenticator(context, &authenticator);
 262         return ret;
 263     }
 264     ret = krb5_crypto_init(context, key, 0, &crypto);
 265     if(ret)
 266         goto out;
 267     ret = krb5_verify_checksum (context,
 268                                 crypto,
 269                                 KRB5_KU_AP_REQ_AUTH_CKSUM,
 270                                 data,
 271                                 len,
 272                                 authenticator->cksum);
 273     krb5_crypto_destroy(context, crypto);
 274 out:
 275     krb5_free_authenticator(context, &authenticator);
 276     krb5_free_keyblock(context, key);
 277     return ret;
 278 }
 279
 280
 281 KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL
 282 krb5_verify_ap_req(krb5_context context,
 283                    krb5_auth_context *auth_context,
 284                    krb5_ap_req *ap_req,
 285                    krb5_const_principal server,
 286                    krb5_keyblock *keyblock,
 287                    krb5_flags flags,
 288                    krb5_flags *ap_req_options,
 289                    krb5_ticket **ticket)
 290 {
 291     return krb5_verify_ap_req2 (context,
 292                                 auth_context,
 293                                 ap_req,
 294                                 server,
 295                                 keyblock,
 296                                 flags,
 297                                 ap_req_options,
 298                                 ticket,
 299                                 KRB5_KU_AP_REQ_AUTH);
 300 }
 301
 302 KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL
 303 krb5_verify_ap_req2(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                     krb5_key_usage usage)
 312 {
 313     krb5_ticket *t;
 314     krb5_auth_context ac;
 315     krb5_error_code ret;
 316     EtypeList etypes;
 317
 318     memset(&etypes, 0, sizeof(etypes));
 319
 320     if (ticket)
 321         *ticket = NULL;
 322
 323     if (auth_context && *auth_context) {
 324         ac = *auth_context;
 325     } else {
 326         ret = krb5_auth_con_init (context, &ac);
 327         if (ret)
 328             return ret;
 329     }
 330
 331     t = calloc(1, sizeof(*t));
 332     if (t == NULL) {
 333         ret = krb5_enomem(context);
 334         goto out;
 335     }
 336
 337     if (ap_req->ap_options.use_session_key && ac->keyblock){
 338         ret = krb5_decrypt_ticket(context, &ap_req->ticket,
 339                                   ac->keyblock,
 340                                   &t->ticket,
 341                                   flags);
 342         krb5_free_keyblock(context, ac->keyblock);
 343         ac->keyblock = NULL;
 344     }else
 345         ret = krb5_decrypt_ticket(context, &ap_req->ticket,
 346                                   keyblock,
 347                                   &t->ticket,
 348                                   flags);
 349
 350     if(ret)
 351         goto out;
 352
 353     ret = _krb5_principalname2krb5_principal(context,
 354                                              &t->server,
 355                                              ap_req->ticket.sname,
 356                                              ap_req->ticket.realm);
 357     if (ret) goto out;
 358     ret = _krb5_principalname2krb5_principal(context,
 359                                              &t->client,
 360                                              t->ticket.cname,
 361                                              t->ticket.crealm);
 362     if (ret) goto out;
 363
 364     ret = decrypt_authenticator (context,
 365                                  &t->ticket.key,
 366                                  &ap_req->authenticator,
 367                                  ac->authenticator,
 368                                  usage);
 369     if (ret)
 370         goto out;
 371
 372     {
 373         krb5_principal p1, p2;
 374         krb5_boolean res;
 375
 376         _krb5_principalname2krb5_principal(context,
 377                                            &p1,
 378                                            ac->authenticator->cname,
 379                                            ac->authenticator->crealm);
 380         _krb5_principalname2krb5_principal(context,
 381                                            &p2,
 382                                            t->ticket.cname,
 383                                            t->ticket.crealm);
 384         res = krb5_principal_compare (context, p1, p2);
 385         krb5_free_principal (context, p1);
 386         krb5_free_principal (context, p2);
 387         if (!res) {
 388             ret = KRB5KRB_AP_ERR_BADMATCH;
 389             krb5_clear_error_message (context);
 390             goto out;
 391         }
 392     }
 393
 394     /* check addresses */
 395
 396     if (t->ticket.caddr
 397         && ac->remote_address
 398         && !krb5_address_search (context,
 399                                  ac->remote_address,
 400                                  t->ticket.caddr)) {
 401         ret = KRB5KRB_AP_ERR_BADADDR;
 402         krb5_clear_error_message (context);
 403         goto out;
 404     }
 405
 406     /* check timestamp in authenticator */
 407     {
 408         krb5_timestamp now;
 409
 410         krb5_timeofday (context, &now);
 411
 412         if (labs(ac->authenticator->ctime - now) > context->max_skew) {
 413             ret = KRB5KRB_AP_ERR_SKEW;
 414             krb5_clear_error_message (context);
 415             goto out;
 416         }
 417     }
 418
 419     if (ac->authenticator->seq_number)
 420         krb5_auth_con_setremoteseqnumber(context, ac,
 421                                          *ac->authenticator->seq_number);
 422
 423     /* XXX - Xor sequence numbers */
 424
 425     if (ac->authenticator->subkey) {
 426         ret = krb5_auth_con_setremotesubkey(context, ac,
 427                                             ac->authenticator->subkey);
 428         if (ret)
 429             goto out;
 430     }
 431
 432     ret = find_etypelist(context, ac, &etypes);
 433     if (ret)
 434         goto out;
 435
 436     ac->keytype = ETYPE_NULL;
 437
 438     if (etypes.val) {
 439         size_t i;
 440
 441         for (i = 0; i < etypes.len; i++) {
 442             if (krb5_enctype_valid(context, etypes.val[i]) == 0) {
 443                 ac->keytype = etypes.val[i];
 444                 break;
 445             }
 446         }
 447     }
 448
 449     /* save key */
 450     ret = krb5_copy_keyblock(context, &t->ticket.key, &ac->keyblock);
 451     if (ret) goto out;
 452
 453     if (ap_req_options) {
 454         *ap_req_options = 0;
 455         if (ac->keytype != (krb5_enctype)ETYPE_NULL)
 456             *ap_req_options |= AP_OPTS_USE_SUBKEY;
 457         if (ap_req->ap_options.use_session_key)
 458             *ap_req_options |= AP_OPTS_USE_SESSION_KEY;
 459         if (ap_req->ap_options.mutual_required)
 460             *ap_req_options |= AP_OPTS_MUTUAL_REQUIRED;
 461     }
 462
 463     if(ticket)
 464         *ticket = t;
 465     else
 466         krb5_free_ticket (context, t);
 467     if (auth_context) {
 468         if (*auth_context == NULL)
 469             *auth_context = ac;
 470     } else
 471         krb5_auth_con_free (context, ac);
 472     free_EtypeList(&etypes);
 473     return 0;
 474  out:
 475     free_EtypeList(&etypes);
 476     if (t)
 477         krb5_free_ticket (context, t);
 478     if (auth_context == NULL || *auth_context == NULL)
 479         krb5_auth_con_free (context, ac);
 480     return ret;
 481 }
 482
 483 /*
 484  *
 485  */
 486
 487 struct krb5_rd_req_in_ctx_data {
 488     krb5_keytab keytab;
 489     krb5_keyblock *keyblock;
 490     krb5_boolean check_pac;
 491 };
 492
 493 struct krb5_rd_req_out_ctx_data {
 494     krb5_keyblock *keyblock;
 495     krb5_flags ap_req_options;
 496     krb5_ticket *ticket;
 497     krb5_principal server;
 498 };
 499
 500 /**
 501  * Allocate a krb5_rd_req_in_ctx as an input parameter to
 502  * krb5_rd_req_ctx(). The caller should free the context with
 503  * krb5_rd_req_in_ctx_free() when done with the context.
 504  *
 505  * @param context Keberos 5 context.
 506  * @param ctx in ctx to krb5_rd_req_ctx().
 507  *
 508  * @return Kerberos 5 error code, see krb5_get_error_message().
 509  *
 510  * @ingroup krb5_auth
 511  */
 512
 513 KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL
 514 krb5_rd_req_in_ctx_alloc(krb5_context context, krb5_rd_req_in_ctx *ctx)
 515 {
 516     *ctx = calloc(1, sizeof(**ctx));
 517     if (*ctx == NULL)
 518         return krb5_enomem(context);
 519     (*ctx)->check_pac = (context->flags & KRB5_CTX_F_CHECK_PAC) ? 1 : 0;
 520     return 0;
 521 }
 522
 523 /**
 524  * Set the keytab that krb5_rd_req_ctx() will use.
 525  *
 526  * @param context Keberos 5 context.
 527  * @param in in ctx to krb5_rd_req_ctx().
 528  * @param keytab keytab that krb5_rd_req_ctx() will use, only copy the
 529  *        pointer, so the caller must free they keytab after
 530  *        krb5_rd_req_in_ctx_free() is called.
 531  *
 532  * @return Kerberos 5 error code, see krb5_get_error_message().
 533  *
 534  * @ingroup krb5_auth
 535  */
 536
 537 KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL
 538 krb5_rd_req_in_set_keytab(krb5_context context,
 539                           krb5_rd_req_in_ctx in,
 540                           krb5_keytab keytab)
 541 {
 542     in->keytab = keytab;
 543     return 0;
 544 }
 545
 546 /**
 547  * Set if krb5_rq_red() is going to check the Windows PAC or not
 548  *
 549  * @param context Keberos 5 context.
 550  * @param in krb5_rd_req_in_ctx to check the option on.
 551  * @param flag flag to select if to check the pac (TRUE) or not (FALSE).
 552  *
 553  * @return Kerberos 5 error code, see krb5_get_error_message().
 554  *
 555  * @ingroup krb5_auth
 556  */
 557
 558 KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL
 559 krb5_rd_req_in_set_pac_check(krb5_context context,
 560                              krb5_rd_req_in_ctx in,
 561                              krb5_boolean flag)
 562 {
 563     in->check_pac = flag;
 564     return 0;
 565 }
 566
 567
 568 KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL
 569 krb5_rd_req_in_set_keyblock(krb5_context context,
 570                             krb5_rd_req_in_ctx in,
 571                             krb5_keyblock *keyblock)
 572 {
 573     in->keyblock = keyblock; /* XXX should make copy */
 574     return 0;
 575 }
 576
 577 KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL
 578 krb5_rd_req_out_get_ap_req_options(krb5_context context,
 579                                    krb5_rd_req_out_ctx out,
 580                                    krb5_flags *ap_req_options)
 581 {
 582     *ap_req_options = out->ap_req_options;
 583     return 0;
 584 }
 585
 586 KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL
 587 krb5_rd_req_out_get_ticket(krb5_context context,
 588                             krb5_rd_req_out_ctx out,
 589                             krb5_ticket **ticket)
 590 {
 591     return krb5_copy_ticket(context, out->ticket, ticket);
 592 }
 593
 594 KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL
 595 krb5_rd_req_out_get_keyblock(krb5_context context,
 596                             krb5_rd_req_out_ctx out,
 597                             krb5_keyblock **keyblock)
 598 {
 599     return krb5_copy_keyblock(context, out->keyblock, keyblock);
 600 }
 601
 602 /**
 603  * Get the principal that was used in the request from the
 604  * client. Might not match whats in the ticket if krb5_rd_req_ctx()
 605  * searched in the keytab for a matching key.
 606  *
 607  * @param context a Kerberos 5 context.
 608  * @param out a krb5_rd_req_out_ctx from krb5_rd_req_ctx().
 609  * @param principal return principal, free with krb5_free_principal().
 610  *
 611  * @ingroup krb5_auth
 612  */
 613
 614 KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL
 615 krb5_rd_req_out_get_server(krb5_context context,
 616                             krb5_rd_req_out_ctx out,
 617                             krb5_principal *principal)
 618 {
 619     return krb5_copy_principal(context, out->server, principal);
 620 }
 621
 622 KRB5_LIB_FUNCTION void KRB5_LIB_CALL
 623 krb5_rd_req_in_ctx_free(krb5_context context, krb5_rd_req_in_ctx ctx)
 624 {
 625     free(ctx);
 626 }
 627
 628 /**
 629  * Free the krb5_rd_req_out_ctx.
 630  *
 631  * @param context Keberos 5 context.
 632  * @param ctx krb5_rd_req_out_ctx context to free.
 633  *
 634  * @ingroup krb5_auth
 635  */
 636
 637 KRB5_LIB_FUNCTION void KRB5_LIB_CALL
 638 krb5_rd_req_out_ctx_free(krb5_context context, krb5_rd_req_out_ctx ctx)
 639 {
 640     if (ctx->ticket)
 641         krb5_free_ticket(context, ctx->ticket);
 642     if (ctx->keyblock)
 643         krb5_free_keyblock(context, ctx->keyblock);
 644     if (ctx->server)
 645         krb5_free_principal(context, ctx->server);
 646     free(ctx);
 647 }
 648
 649 /**
 650  * Process an AP_REQ message.
 651  *
 652  * @param context        Kerberos 5 context.
 653  * @param auth_context   authentication context of the peer.
 654  * @param inbuf          the AP_REQ message, obtained for example with krb5_read_message().
 655  * @param server         server principal.
 656  * @param keytab         server keytab.
 657  * @param ap_req_options set to the AP_REQ options. See the AP_OPTS_* defines.
 658  * @param ticket         on success, set to the authenticated client credentials.
 659  *                       Must be deallocated with krb5_free_ticket(). If not
 660  *                       interested, pass a NULL value.
 661  *
 662  * @return 0 to indicate success. Otherwise a Kerberos error code is
 663  *         returned, see krb5_get_error_message().
 664  */
 665 KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL
 666 krb5_rd_req(krb5_context context,
 667             krb5_auth_context *auth_context,
 668             const krb5_data *inbuf,
 669             krb5_const_principal server,
 670             krb5_keytab keytab,
 671             krb5_flags *ap_req_options,
 672             krb5_ticket **ticket)
 673 {
 674     krb5_error_code ret;
 675     krb5_rd_req_in_ctx in;
 676     krb5_rd_req_out_ctx out;
 677
 678     ret = krb5_rd_req_in_ctx_alloc(context, &in);
 679     if (ret)
 680         return ret;
 681
 682     ret = krb5_rd_req_in_set_keytab(context, in, keytab);
 683     if (ret) {
 684         krb5_rd_req_in_ctx_free(context, in);
 685         return ret;
 686     }
 687
 688     ret = krb5_rd_req_ctx(context, auth_context, inbuf, server, in, &out);
 689     krb5_rd_req_in_ctx_free(context, in);
 690     if (ret)
 691         return ret;
 692
 693     if (ap_req_options)
 694         *ap_req_options = out->ap_req_options;
 695     if (ticket) {
 696         ret = krb5_copy_ticket(context, out->ticket, ticket);
 697         if (ret)
 698             goto out;
 699     }
 700
 701 out:
 702     krb5_rd_req_out_ctx_free(context, out);
 703     return ret;
 704 }
 705
 706 /*
 707  *
 708  */
 709
 710 KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL
 711 krb5_rd_req_with_keyblock(krb5_context context,
 712                           krb5_auth_context *auth_context,
 713                           const krb5_data *inbuf,
 714                           krb5_const_principal server,
 715                           krb5_keyblock *keyblock,
 716                           krb5_flags *ap_req_options,
 717                           krb5_ticket **ticket)
 718 {
 719     krb5_error_code ret;
 720     krb5_rd_req_in_ctx in;
 721     krb5_rd_req_out_ctx out;
 722
 723     ret = krb5_rd_req_in_ctx_alloc(context, &in);
 724     if (ret)
 725         return ret;
 726
 727     ret = krb5_rd_req_in_set_keyblock(context, in, keyblock);
 728     if (ret) {
 729         krb5_rd_req_in_ctx_free(context, in);
 730         return ret;
 731     }
 732
 733     ret = krb5_rd_req_ctx(context, auth_context, inbuf, server, in, &out);
 734     krb5_rd_req_in_ctx_free(context, in);
 735     if (ret)
 736         return ret;
 737
 738     if (ap_req_options)
 739         *ap_req_options = out->ap_req_options;
 740     if (ticket) {
 741         ret = krb5_copy_ticket(context, out->ticket, ticket);
 742         if (ret)
 743             goto out;
 744     }
 745
 746 out:
 747     krb5_rd_req_out_ctx_free(context, out);
 748     return ret;
 749 }
 750
 751 /*
 752  *
 753  */
 754
 755 static krb5_error_code
 756 get_key_from_keytab(krb5_context context,
 757                     krb5_ap_req *ap_req,
 758                     krb5_const_principal server,
 759                     krb5_keytab keytab,
 760                     krb5_keyblock **out_key)
 761 {
 762     krb5_keytab_entry entry;
 763     krb5_error_code ret;
 764     int kvno;
 765     krb5_keytab real_keytab;
 766
 767     if(keytab == NULL)
 768         krb5_kt_default(context, &real_keytab);
 769     else
 770         real_keytab = keytab;
 771
 772     if (ap_req->ticket.enc_part.kvno)
 773         kvno = *ap_req->ticket.enc_part.kvno;
 774     else
 775         kvno = 0;
 776
 777     ret = krb5_kt_get_entry (context,
 778                              real_keytab,
 779                              server,
 780                              kvno,
 781                              ap_req->ticket.enc_part.etype,
 782                              &entry);
 783     if(ret)
 784         goto out;
 785     ret = krb5_copy_keyblock(context, &entry.keyblock, out_key);
 786     krb5_kt_free_entry (context, &entry);
 787 out:
 788     if(keytab == NULL)
 789         krb5_kt_close(context, real_keytab);
 790
 791     return ret;
 792 }
 793
 794 /**
 795  * The core server function that verify application authentication
 796  * requests from clients.
 797  *
 798  * @param context Keberos 5 context.
 799  * @param auth_context the authentication context, can be NULL, then
 800  *        default values for the authentication context will used.
 801  * @param inbuf the (AP-REQ) authentication buffer
 802  *
 803  * @param server the server to authenticate to. If NULL the function
 804  *        will try to find any available credential in the keytab
 805  *        that will verify the reply. The function will prefer the
 806  *        server specified in the AP-REQ, but if
 807  *        there is no mach, it will try all keytab entries for a
 808  *        match. This has serious performance issues for large keytabs.
 809  *
 810  * @param inctx control the behavior of the function, if NULL, the
 811  *        default behavior is used.
 812  * @param outctx the return outctx, free with krb5_rd_req_out_ctx_free().
 813  * @return Kerberos 5 error code, see krb5_get_error_message().
 814  *
 815  * @ingroup krb5_auth
 816  */
 817
 818 KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL
 819 krb5_rd_req_ctx(krb5_context context,
 820                 krb5_auth_context *auth_context,
 821                 const krb5_data *inbuf,
 822                 krb5_const_principal server,
 823                 krb5_rd_req_in_ctx inctx,
 824                 krb5_rd_req_out_ctx *outctx)
 825 {
 826     krb5_error_code ret;
 827     krb5_ap_req ap_req;
 828     krb5_rd_req_out_ctx o = NULL;
 829     krb5_keytab id = NULL, keytab = NULL;
 830     krb5_principal service = NULL;
 831
 832     *outctx = NULL;
 833
 834     o = calloc(1, sizeof(*o));
 835     if (o == NULL)
 836         return krb5_enomem(context);
 837
 838     if (*auth_context == NULL) {
 839         ret = krb5_auth_con_init(context, auth_context);
 840         if (ret)
 841             goto out;
 842     }
 843
 844     ret = krb5_decode_ap_req(context, inbuf, &ap_req);
 845     if(ret)
 846         goto out;
 847
 848     /* Save the principal that was in the request */
 849     ret = _krb5_principalname2krb5_principal(context,
 850                                              &o->server,
 851                                              ap_req.ticket.sname,
 852                                              ap_req.ticket.realm);
 853     if (ret)
 854         goto out;
 855
 856     if (ap_req.ap_options.use_session_key &&
 857         (*auth_context)->keyblock == NULL) {
 858         ret = KRB5KRB_AP_ERR_NOKEY;
 859         krb5_set_error_message(context, ret,
 860                                N_("krb5_rd_req: user to user auth "
 861                                   "without session key given", ""));
 862         goto out;
 863     }
 864
 865     if (inctx && inctx->keytab)
 866         id = inctx->keytab;
 867
 868     if((*auth_context)->keyblock){
 869         ret = krb5_copy_keyblock(context,
 870                                  (*auth_context)->keyblock,
 871                                  &o->keyblock);
 872         if (ret)
 873             goto out;
 874     } else if(inctx && inctx->keyblock){
 875         ret = krb5_copy_keyblock(context,
 876                                  inctx->keyblock,
 877                                  &o->keyblock);
 878         if (ret)
 879             goto out;
 880     } else {
 881
 882         if(id == NULL) {
 883             krb5_kt_default(context, &keytab);
 884             id = keytab;
 885         }
 886         if (id == NULL)
 887             goto out;
 888
 889         if (server == NULL) {
 890             ret = _krb5_principalname2krb5_principal(context,
 891                                                      &service,
 892                                                      ap_req.ticket.sname,
 893                                                      ap_req.ticket.realm);
 894             if (ret)
 895                 goto out;
 896             server = service;
 897         }
 898
 899         ret = get_key_from_keytab(context,
 900                                   &ap_req,
 901                                   server,
 902                                   id,
 903                                   &o->keyblock);
 904         if (ret) {
 905             /* If caller specified a server, fail. */
 906             if (service == NULL && (context->flags & KRB5_CTX_F_RD_REQ_IGNORE) == 0)
 907                 goto out;
 908             /* Otherwise, fall back to iterating over the keytab. This
 909              * have serious performace issues for larger keytab.
 910              */
 911             o->keyblock = NULL;
 912         }
 913     }
 914
 915     if (o->keyblock) {
 916         /*
 917          * We got an exact keymatch, use that.
 918          */
 919
 920         ret = krb5_verify_ap_req2(context,
 921                                   auth_context,
 922                                   &ap_req,
 923                                   server,
 924                                   o->keyblock,
 925                                   0,
 926                                   &o->ap_req_options,
 927                                   &o->ticket,
 928                                   KRB5_KU_AP_REQ_AUTH);
 929
 930         if (ret)
 931             goto out;
 932
 933     } else {
 934         /*
 935          * Interate over keytab to find a key that can decrypt the request.
 936          */
 937
 938         krb5_keytab_entry entry;
 939         krb5_kt_cursor cursor;
 940         int done = 0, kvno = 0;
 941
 942         memset(&cursor, 0, sizeof(cursor));
 943
 944         if (ap_req.ticket.enc_part.kvno)
 945             kvno = *ap_req.ticket.enc_part.kvno;
 946
 947         ret = krb5_kt_start_seq_get(context, id, &cursor);
 948         if (ret)
 949             goto out;
 950
 951         done = 0;
 952         while (!done) {
 953             krb5_principal p;
 954
 955             ret = krb5_kt_next_entry(context, id, &entry, &cursor);
 956             if (ret) {
 957                 _krb5_kt_principal_not_found(context, ret, id, o->server,
 958                                              ap_req.ticket.enc_part.etype,
 959                                              kvno);
 960                 break;
 961             }
 962
 963             if (entry.keyblock.keytype != ap_req.ticket.enc_part.etype) {
 964                 krb5_kt_free_entry (context, &entry);
 965                 continue;
 966             }
 967
 968             ret = krb5_verify_ap_req2(context,
 969                                       auth_context,
 970                                       &ap_req,
 971                                       server,
 972                                       &entry.keyblock,
 973                                       0,
 974                                       &o->ap_req_options,
 975                                       &o->ticket,
 976                                       KRB5_KU_AP_REQ_AUTH);
 977             if (ret) {
 978                 krb5_kt_free_entry (context, &entry);
 979                 continue;
 980             }
 981
 982             /*
 983              * Found a match, save the keyblock for PAC processing,
 984              * and update the service principal in the ticket to match
 985              * whatever is in the keytab.
 986              */
 987
 988             ret = krb5_copy_keyblock(context,
 989                                      &entry.keyblock,
 990                                      &o->keyblock);
 991             if (ret) {
 992                 krb5_kt_free_entry (context, &entry);
 993                 break;
 994             }
 995
 996             ret = krb5_copy_principal(context, entry.principal, &p);
 997             if (ret) {
 998                 krb5_kt_free_entry (context, &entry);
 999                 break;
1000             }
1001             krb5_free_principal(context, o->ticket->server);
1002             o->ticket->server = p;
1003
1004             krb5_kt_free_entry (context, &entry);
1005
1006             done = 1;
1007         }
1008         krb5_kt_end_seq_get (context, id, &cursor);
1009         if (ret)
1010             goto out;
1011     }
1012
1013     /* If there is a PAC, verify its server signature */
1014     if (inctx == NULL || inctx->check_pac) {
1015         krb5_pac pac;
1016         krb5_data data;
1017
1018         ret = krb5_ticket_get_authorization_data_type(context,
1019                                                       o->ticket,
1020                                                       KRB5_AUTHDATA_WIN2K_PAC,
1021                                                       &data);
1022         if (ret == 0) {
1023             ret = krb5_pac_parse(context, data.data, data.length, &pac);
1024             krb5_data_free(&data);
1025             if (ret)
1026                 goto out;
1027
1028             ret = krb5_pac_verify(context,
1029                                   pac,
1030                                   o->ticket->ticket.authtime,
1031                                   o->ticket->client,
1032                                   o->keyblock,
1033                                   NULL);
1034             krb5_pac_free(context, pac);
1035             if (ret)
1036                 goto out;
1037         } else
1038           ret = 0;
1039     }
1040 out:
1041
1042     if (ret || outctx == NULL) {
1043         krb5_rd_req_out_ctx_free(context, o);
1044     } else
1045         *outctx = o;
1046
1047     free_AP_REQ(&ap_req);
1048
1049     if (service)
1050         krb5_free_principal(context, service);
1051
1052     if (keytab)
1053         krb5_kt_close(context, keytab);
1054
1055     return ret;
1056 }