source4/heimdal/lib/krb5/rd_req.c

   1 /*
   2  * Copyright (c) 1997 - 2007 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 static krb5_error_code
  37 decrypt_tkt_enc_part (krb5_context context,
  38                       krb5_keyblock *key,
  39                       EncryptedData *enc_part,
  40                       EncTicketPart *decr_part)
  41 {
  42     krb5_error_code ret;
  43     krb5_data plain;
  44     size_t len;
  45     krb5_crypto crypto;
  46
  47     ret = krb5_crypto_init(context, key, 0, &crypto);
  48     if (ret)
  49         return ret;
  50     ret = krb5_decrypt_EncryptedData (context,
  51                                       crypto,
  52                                       KRB5_KU_TICKET,
  53                                       enc_part,
  54                                       &plain);
  55     krb5_crypto_destroy(context, crypto);
  56     if (ret)
  57         return ret;
  58
  59     ret = decode_EncTicketPart(plain.data, plain.length, decr_part, &len);
  60     if (ret)
  61         krb5_set_error_message(context, ret,
  62                                N_("Failed to decode encrypted "
  63                                   "ticket part", ""));
  64     krb5_data_free (&plain);
  65     return ret;
  66 }
  67
  68 static krb5_error_code
  69 decrypt_authenticator (krb5_context context,
  70                        EncryptionKey *key,
  71                        EncryptedData *enc_part,
  72                        Authenticator *authenticator,
  73                        krb5_key_usage usage)
  74 {
  75     krb5_error_code ret;
  76     krb5_data plain;
  77     size_t len;
  78     krb5_crypto crypto;
  79
  80     ret = krb5_crypto_init(context, key, 0, &crypto);
  81     if (ret)
  82         return ret;
  83     ret = krb5_decrypt_EncryptedData (context,
  84                                       crypto,
  85                                       usage /* KRB5_KU_AP_REQ_AUTH */,
  86                                       enc_part,
  87                                       &plain);
  88     /* for backwards compatibility, also try the old usage */
  89     if (ret && usage == KRB5_KU_TGS_REQ_AUTH)
  90         ret = krb5_decrypt_EncryptedData (context,
  91                                           crypto,
  92                                           KRB5_KU_AP_REQ_AUTH,
  93                                           enc_part,
  94                                           &plain);
  95     krb5_crypto_destroy(context, crypto);
  96     if (ret)
  97         return ret;
  98
  99     ret = decode_Authenticator(plain.data, plain.length,
 100                                authenticator, &len);
 101     krb5_data_free (&plain);
 102     return ret;
 103 }
 104
 105 krb5_error_code KRB5_LIB_FUNCTION
 106 krb5_decode_ap_req(krb5_context context,
 107                    const krb5_data *inbuf,
 108                    krb5_ap_req *ap_req)
 109 {
 110     krb5_error_code ret;
 111     size_t len;
 112     ret = decode_AP_REQ(inbuf->data, inbuf->length, ap_req, &len);
 113     if (ret)
 114         return ret;
 115     if (ap_req->pvno != 5){
 116         free_AP_REQ(ap_req);
 117         krb5_clear_error_message (context);
 118         return KRB5KRB_AP_ERR_BADVERSION;
 119     }
 120     if (ap_req->msg_type != krb_ap_req){
 121         free_AP_REQ(ap_req);
 122         krb5_clear_error_message (context);
 123         return KRB5KRB_AP_ERR_MSG_TYPE;
 124     }
 125     if (ap_req->ticket.tkt_vno != 5){
 126         free_AP_REQ(ap_req);
 127         krb5_clear_error_message (context);
 128         return KRB5KRB_AP_ERR_BADVERSION;
 129     }
 130     return 0;
 131 }
 132
 133 static krb5_error_code
 134 check_transited(krb5_context context, Ticket *ticket, EncTicketPart *enc)
 135 {
 136     char **realms;
 137     unsigned int num_realms;
 138     krb5_error_code ret;
 139
 140     /*
 141      * Windows 2000 and 2003 uses this inside their TGT so it's normaly
 142      * not seen by others, however, samba4 joined with a Windows AD as
 143      * a Domain Controller gets exposed to this.
 144      */
 145     if(enc->transited.tr_type == 0 && enc->transited.contents.length == 0)
 146         return 0;
 147
 148     if(enc->transited.tr_type != DOMAIN_X500_COMPRESS)
 149         return KRB5KDC_ERR_TRTYPE_NOSUPP;
 150
 151     if(enc->transited.contents.length == 0)
 152         return 0;
 153
 154     ret = krb5_domain_x500_decode(context, enc->transited.contents,
 155                                   &realms, &num_realms,
 156                                   enc->crealm,
 157                                   ticket->realm);
 158     if(ret)
 159         return ret;
 160     ret = krb5_check_transited(context, enc->crealm,
 161                                ticket->realm,
 162                                realms, num_realms, NULL);
 163     free(realms);
 164     return ret;
 165 }
 166
 167 static krb5_error_code
 168 find_etypelist(krb5_context context,
 169                krb5_auth_context auth_context,
 170                EtypeList *etypes)
 171 {
 172     krb5_error_code ret;
 173     krb5_authdata *ad;
 174     krb5_authdata adIfRelevant;
 175     unsigned i;
 176
 177     adIfRelevant.len = 0;
 178
 179     etypes->len = 0;
 180     etypes->val = NULL;
 181
 182     ad = auth_context->authenticator->authorization_data;
 183     if (ad == NULL)
 184         return 0;
 185
 186     for (i = 0; i < ad->len; i++) {
 187         if (ad->val[i].ad_type == KRB5_AUTHDATA_IF_RELEVANT) {
 188             ret = decode_AD_IF_RELEVANT(ad->val[i].ad_data.data,
 189                                         ad->val[i].ad_data.length,
 190                                         &adIfRelevant,
 191                                         NULL);
 192             if (ret)
 193                 return ret;
 194
 195             if (adIfRelevant.len == 1 &&
 196                 adIfRelevant.val[0].ad_type ==
 197                         KRB5_AUTHDATA_GSS_API_ETYPE_NEGOTIATION) {
 198                 break;
 199             }
 200             free_AD_IF_RELEVANT(&adIfRelevant);
 201             adIfRelevant.len = 0;
 202         }
 203     }
 204
 205     if (adIfRelevant.len == 0)
 206         return 0;
 207
 208     ret = decode_EtypeList(adIfRelevant.val[0].ad_data.data,
 209                            adIfRelevant.val[0].ad_data.length,
 210                            etypes,
 211                            NULL);
 212     if (ret)
 213         krb5_clear_error_message(context);
 214
 215     free_AD_IF_RELEVANT(&adIfRelevant);
 216
 217     return ret;
 218 }
 219
 220 krb5_error_code KRB5_LIB_FUNCTION
 221 krb5_decrypt_ticket(krb5_context context,
 222                     Ticket *ticket,
 223                     krb5_keyblock *key,
 224                     EncTicketPart *out,
 225                     krb5_flags flags)
 226 {
 227     EncTicketPart t;
 228     krb5_error_code ret;
 229     ret = decrypt_tkt_enc_part (context, key, &ticket->enc_part, &t);
 230     if (ret)
 231         return ret;
 232
 233     {
 234         krb5_timestamp now;
 235         time_t start = t.authtime;
 236
 237         krb5_timeofday (context, &now);
 238         if(t.starttime)
 239             start = *t.starttime;
 240         if(start - now > context->max_skew
 241            || (t.flags.invalid
 242                && !(flags & KRB5_VERIFY_AP_REQ_IGNORE_INVALID))) {
 243             free_EncTicketPart(&t);
 244             krb5_clear_error_message (context);
 245             return KRB5KRB_AP_ERR_TKT_NYV;
 246         }
 247         if(now - t.endtime > context->max_skew) {
 248             free_EncTicketPart(&t);
 249             krb5_clear_error_message (context);
 250             return KRB5KRB_AP_ERR_TKT_EXPIRED;
 251         }
 252
 253         if(!t.flags.transited_policy_checked) {
 254             ret = check_transited(context, ticket, &t);
 255             if(ret) {
 256                 free_EncTicketPart(&t);
 257                 return ret;
 258             }
 259         }
 260     }
 261
 262     if(out)
 263         *out = t;
 264     else
 265         free_EncTicketPart(&t);
 266     return 0;
 267 }
 268
 269 krb5_error_code KRB5_LIB_FUNCTION
 270 krb5_verify_authenticator_checksum(krb5_context context,
 271                                    krb5_auth_context ac,
 272                                    void *data,
 273                                    size_t len)
 274 {
 275     krb5_error_code ret;
 276     krb5_keyblock *key;
 277     krb5_authenticator authenticator;
 278     krb5_crypto crypto;
 279
 280     ret = krb5_auth_con_getauthenticator (context,
 281                                       ac,
 282                                       &authenticator);
 283     if(ret)
 284         return ret;
 285     if(authenticator->cksum == NULL) {
 286         krb5_free_authenticator(context, &authenticator);
 287         return -17;
 288     }
 289     ret = krb5_auth_con_getkey(context, ac, &key);
 290     if(ret) {
 291         krb5_free_authenticator(context, &authenticator);
 292         return ret;
 293     }
 294     ret = krb5_crypto_init(context, key, 0, &crypto);
 295     if(ret)
 296         goto out;
 297     ret = krb5_verify_checksum (context,
 298                                 crypto,
 299                                 KRB5_KU_AP_REQ_AUTH_CKSUM,
 300                                 data,
 301                                 len,
 302                                 authenticator->cksum);
 303     krb5_crypto_destroy(context, crypto);
 304 out:
 305     krb5_free_authenticator(context, &authenticator);
 306     krb5_free_keyblock(context, key);
 307     return ret;
 308 }
 309
 310
 311 krb5_error_code KRB5_LIB_FUNCTION
 312 krb5_verify_ap_req(krb5_context context,
 313                    krb5_auth_context *auth_context,
 314                    krb5_ap_req *ap_req,
 315                    krb5_const_principal server,
 316                    krb5_keyblock *keyblock,
 317                    krb5_flags flags,
 318                    krb5_flags *ap_req_options,
 319                    krb5_ticket **ticket)
 320 {
 321     return krb5_verify_ap_req2 (context,
 322                                 auth_context,
 323                                 ap_req,
 324                                 server,
 325                                 keyblock,
 326                                 flags,
 327                                 ap_req_options,
 328                                 ticket,
 329                                 KRB5_KU_AP_REQ_AUTH);
 330 }
 331
 332 krb5_error_code KRB5_LIB_FUNCTION
 333 krb5_verify_ap_req2(krb5_context context,
 334                     krb5_auth_context *auth_context,
 335                     krb5_ap_req *ap_req,
 336                     krb5_const_principal server,
 337                     krb5_keyblock *keyblock,
 338                     krb5_flags flags,
 339                     krb5_flags *ap_req_options,
 340                     krb5_ticket **ticket,
 341                     krb5_key_usage usage)
 342 {
 343     krb5_ticket *t;
 344     krb5_auth_context ac;
 345     krb5_error_code ret;
 346     EtypeList etypes;
 347
 348     if (ticket)
 349         *ticket = NULL;
 350
 351     if (auth_context && *auth_context) {
 352         ac = *auth_context;
 353     } else {
 354         ret = krb5_auth_con_init (context, &ac);
 355         if (ret)
 356             return ret;
 357     }
 358
 359     t = calloc(1, sizeof(*t));
 360     if (t == NULL) {
 361         ret = ENOMEM;
 362         krb5_clear_error_message (context);
 363         goto out;
 364     }
 365
 366     if (ap_req->ap_options.use_session_key && ac->keyblock){
 367         ret = krb5_decrypt_ticket(context, &ap_req->ticket,
 368                                   ac->keyblock,
 369                                   &t->ticket,
 370                                   flags);
 371         krb5_free_keyblock(context, ac->keyblock);
 372         ac->keyblock = NULL;
 373     }else
 374         ret = krb5_decrypt_ticket(context, &ap_req->ticket,
 375                                   keyblock,
 376                                   &t->ticket,
 377                                   flags);
 378
 379     if(ret)
 380         goto out;
 381
 382     ret = _krb5_principalname2krb5_principal(context,
 383                                              &t->server,
 384                                              ap_req->ticket.sname,
 385                                              ap_req->ticket.realm);
 386     if (ret) goto out;
 387     ret = _krb5_principalname2krb5_principal(context,
 388                                              &t->client,
 389                                              t->ticket.cname,
 390                                              t->ticket.crealm);
 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,
 406                                            &p1,
 407                                            ac->authenticator->cname,
 408                                            ac->authenticator->crealm);
 409         _krb5_principalname2krb5_principal(context,
 410                                            &p2,
 411                                            t->ticket.cname,
 412                                            t->ticket.crealm);
 413         res = krb5_principal_compare (context, p1, p2);
 414         krb5_free_principal (context, p1);
 415         krb5_free_principal (context, p2);
 416         if (!res) {
 417             ret = KRB5KRB_AP_ERR_BADMATCH;
 418             krb5_clear_error_message (context);
 419             goto out;
 420         }
 421     }
 422
 423     /* check addresses */
 424
 425     if (t->ticket.caddr
 426         && ac->remote_address
 427         && !krb5_address_search (context,
 428                                  ac->remote_address,
 429                                  t->ticket.caddr)) {
 430         ret = KRB5KRB_AP_ERR_BADADDR;
 431         krb5_clear_error_message (context);
 432         goto out;
 433     }
 434
 435     /* check timestamp in authenticator */
 436     {
 437         krb5_timestamp now;
 438
 439         krb5_timeofday (context, &now);
 440
 441         if (abs(ac->authenticator->ctime - now) > context->max_skew) {
 442             ret = KRB5KRB_AP_ERR_SKEW;
 443             krb5_clear_error_message (context);
 444             goto out;
 445         }
 446     }
 447
 448     if (ac->authenticator->seq_number)
 449         krb5_auth_con_setremoteseqnumber(context, ac,
 450                                          *ac->authenticator->seq_number);
 451
 452     /* XXX - Xor sequence numbers */
 453
 454     if (ac->authenticator->subkey) {
 455         ret = krb5_auth_con_setremotesubkey(context, ac,
 456                                             ac->authenticator->subkey);
 457         if (ret)
 458             goto out;
 459     }
 460
 461     ret = find_etypelist(context, ac, &etypes);
 462     if (ret)
 463         goto out;
 464
 465     ac->keytype = ETYPE_NULL;
 466
 467     if (etypes.val) {
 468         int i;
 469
 470         for (i = 0; i < etypes.len; i++) {
 471             if (krb5_enctype_valid(context, etypes.val[i]) == 0) {
 472                 ac->keytype = etypes.val[i];
 473                 break;
 474             }
 475         }
 476     }
 477
 478     /* save key */
 479     ret = krb5_copy_keyblock(context, &t->ticket.key, &ac->keyblock);
 480     if (ret) goto out;
 481
 482     if (ap_req_options) {
 483         *ap_req_options = 0;
 484         if (ac->keytype != ETYPE_NULL)
 485             *ap_req_options |= AP_OPTS_USE_SUBKEY;
 486         if (ap_req->ap_options.use_session_key)
 487             *ap_req_options |= AP_OPTS_USE_SESSION_KEY;
 488         if (ap_req->ap_options.mutual_required)
 489             *ap_req_options |= AP_OPTS_MUTUAL_REQUIRED;
 490     }
 491
 492     if(ticket)
 493         *ticket = t;
 494     else
 495         krb5_free_ticket (context, t);
 496     if (auth_context) {
 497         if (*auth_context == NULL)
 498             *auth_context = ac;
 499     } else
 500         krb5_auth_con_free (context, ac);
 501     free_EtypeList(&etypes);
 502     return 0;
 503  out:
 504     if (t)
 505         krb5_free_ticket (context, t);
 506     if (auth_context == NULL || *auth_context == NULL)
 507         krb5_auth_con_free (context, ac);
 508     return ret;
 509 }
 510
 511 /*
 512  *
 513  */
 514
 515 struct krb5_rd_req_in_ctx_data {
 516     krb5_keytab keytab;
 517     krb5_keyblock *keyblock;
 518     krb5_boolean check_pac;
 519 };
 520
 521 struct krb5_rd_req_out_ctx_data {
 522     krb5_keyblock *keyblock;
 523     krb5_flags ap_req_options;
 524     krb5_ticket *ticket;
 525     krb5_principal server;
 526 };
 527
 528 /**
 529  * Allocate a krb5_rd_req_in_ctx as an input parameter to
 530  * krb5_rd_req_ctx(). The caller should free the context with
 531  * krb5_rd_req_in_ctx_free() when done with the context.
 532  *
 533  * @param context Keberos 5 context.
 534  * @param ctx in ctx to krb5_rd_req_ctx().
 535  *
 536  * @return Kerberos 5 error code, see krb5_get_error_message().
 537  *
 538  * @ingroup krb5_auth
 539  */
 540
 541 krb5_error_code KRB5_LIB_FUNCTION
 542 krb5_rd_req_in_ctx_alloc(krb5_context context, krb5_rd_req_in_ctx *ctx)
 543 {
 544     *ctx = calloc(1, sizeof(**ctx));
 545     if (*ctx == NULL) {
 546         krb5_set_error_message(context, ENOMEM,
 547                                N_("malloc: out of memory", ""));
 548         return ENOMEM;
 549     }
 550     (*ctx)->check_pac = (context->flags & KRB5_CTX_F_CHECK_PAC) ? 1 : 0;
 551     return 0;
 552 }
 553
 554 /**
 555  * Set the keytab that krb5_rd_req_ctx() will use.
 556  *
 557  * @param context Keberos 5 context.
 558  * @param in in ctx to krb5_rd_req_ctx().
 559  * @param keytab keytab that krb5_rd_req_ctx() will use, only copy the
 560  *        pointer, so the caller must free they keytab after
 561  *        krb5_rd_req_in_ctx_free() is called.
 562  *
 563  * @return Kerberos 5 error code, see krb5_get_error_message().
 564  *
 565  * @ingroup krb5_auth
 566  */
 567
 568 krb5_error_code KRB5_LIB_FUNCTION
 569 krb5_rd_req_in_set_keytab(krb5_context context,
 570                           krb5_rd_req_in_ctx in,
 571                           krb5_keytab keytab)
 572 {
 573     in->keytab = keytab;
 574     return 0;
 575 }
 576
 577 /**
 578  * Set if krb5_rq_red() is going to check the Windows PAC or not
 579  *
 580  * @param context Keberos 5 context.
 581  * @param in krb5_rd_req_in_ctx to check the option on.
 582  * @param flag flag to select if to check the pac (TRUE) or not (FALSE).
 583  *
 584  * @return Kerberos 5 error code, see krb5_get_error_message().
 585  *
 586  * @ingroup krb5_auth
 587  */
 588
 589 krb5_error_code KRB5_LIB_FUNCTION
 590 krb5_rd_req_in_set_pac_check(krb5_context context,
 591                              krb5_rd_req_in_ctx in,
 592                              krb5_boolean flag)
 593 {
 594     in->check_pac = flag;
 595     return 0;
 596 }
 597
 598
 599 krb5_error_code KRB5_LIB_FUNCTION
 600 krb5_rd_req_in_set_keyblock(krb5_context context,
 601                             krb5_rd_req_in_ctx in,
 602                             krb5_keyblock *keyblock)
 603 {
 604     in->keyblock = keyblock; /* XXX should make copy */
 605     return 0;
 606 }
 607
 608 krb5_error_code KRB5_LIB_FUNCTION
 609 krb5_rd_req_out_get_ap_req_options(krb5_context context,
 610                                    krb5_rd_req_out_ctx out,
 611                                    krb5_flags *ap_req_options)
 612 {
 613     *ap_req_options = out->ap_req_options;
 614     return 0;
 615 }
 616
 617 krb5_error_code KRB5_LIB_FUNCTION
 618 krb5_rd_req_out_get_ticket(krb5_context context,
 619                             krb5_rd_req_out_ctx out,
 620                             krb5_ticket **ticket)
 621 {
 622     return krb5_copy_ticket(context, out->ticket, ticket);
 623 }
 624
 625 krb5_error_code KRB5_LIB_FUNCTION
 626 krb5_rd_req_out_get_keyblock(krb5_context context,
 627                             krb5_rd_req_out_ctx out,
 628                             krb5_keyblock **keyblock)
 629 {
 630     return krb5_copy_keyblock(context, out->keyblock, keyblock);
 631 }
 632
 633 /**
 634  * Get the principal that was used in the request from the
 635  * client. Might not match whats in the ticket if krb5_rd_req_ctx()
 636  * searched in the keytab for a matching key.
 637  *
 638  * @param context a Kerberos 5 context.
 639  * @param out a krb5_rd_req_out_ctx from krb5_rd_req_ctx().
 640  * @param principal return principal, free with krb5_free_principal().
 641  *
 642  * @ingroup krb5_auth
 643  */
 644
 645 krb5_error_code KRB5_LIB_FUNCTION
 646 krb5_rd_req_out_get_server(krb5_context context,
 647                             krb5_rd_req_out_ctx out,
 648                             krb5_principal *principal)
 649 {
 650     return krb5_copy_principal(context, out->server, principal);
 651 }
 652
 653 void  KRB5_LIB_FUNCTION
 654 krb5_rd_req_in_ctx_free(krb5_context context, krb5_rd_req_in_ctx ctx)
 655 {
 656     free(ctx);
 657 }
 658
 659 /**
 660  * Free the krb5_rd_req_out_ctx.
 661  *
 662  * @param context Keberos 5 context.
 663  * @param ctx krb5_rd_req_out_ctx context to free.
 664  *
 665  * @ingroup krb5_auth
 666  */
 667
 668 void  KRB5_LIB_FUNCTION
 669 krb5_rd_req_out_ctx_free(krb5_context context, krb5_rd_req_out_ctx ctx)
 670 {
 671     if (ctx->ticket)
 672         krb5_free_ticket(context, ctx->ticket);
 673     if (ctx->keyblock)
 674         krb5_free_keyblock(context, ctx->keyblock);
 675     if (ctx->server)
 676         krb5_free_principal(context, ctx->server);
 677     free(ctx);
 678 }
 679
 680 /*
 681  *
 682  */
 683
 684 krb5_error_code KRB5_LIB_FUNCTION
 685 krb5_rd_req(krb5_context context,
 686             krb5_auth_context *auth_context,
 687             const krb5_data *inbuf,
 688             krb5_const_principal server,
 689             krb5_keytab keytab,
 690             krb5_flags *ap_req_options,
 691             krb5_ticket **ticket)
 692 {
 693     krb5_error_code ret;
 694     krb5_rd_req_in_ctx in;
 695     krb5_rd_req_out_ctx out;
 696
 697     ret = krb5_rd_req_in_ctx_alloc(context, &in);
 698     if (ret)
 699         return ret;
 700
 701     ret = krb5_rd_req_in_set_keytab(context, in, keytab);
 702     if (ret) {
 703         krb5_rd_req_in_ctx_free(context, in);
 704         return ret;
 705     }
 706
 707     ret = krb5_rd_req_ctx(context, auth_context, inbuf, server, in, &out);
 708     krb5_rd_req_in_ctx_free(context, in);
 709     if (ret)
 710         return ret;
 711
 712     if (ap_req_options)
 713         *ap_req_options = out->ap_req_options;
 714     if (ticket) {
 715         ret = krb5_copy_ticket(context, out->ticket, ticket);
 716         if (ret)
 717             goto out;
 718     }
 719
 720 out:
 721     krb5_rd_req_out_ctx_free(context, out);
 722     return ret;
 723 }
 724
 725 /*
 726  *
 727  */
 728
 729 krb5_error_code KRB5_LIB_FUNCTION
 730 krb5_rd_req_with_keyblock(krb5_context context,
 731                           krb5_auth_context *auth_context,
 732                           const krb5_data *inbuf,
 733                           krb5_const_principal server,
 734                           krb5_keyblock *keyblock,
 735                           krb5_flags *ap_req_options,
 736                           krb5_ticket **ticket)
 737 {
 738     krb5_error_code ret;
 739     krb5_rd_req_in_ctx in;
 740     krb5_rd_req_out_ctx out;
 741
 742     ret = krb5_rd_req_in_ctx_alloc(context, &in);
 743     if (ret)
 744         return ret;
 745
 746     ret = krb5_rd_req_in_set_keyblock(context, in, keyblock);
 747     if (ret) {
 748         krb5_rd_req_in_ctx_free(context, in);
 749         return ret;
 750     }
 751
 752     ret = krb5_rd_req_ctx(context, auth_context, inbuf, server, in, &out);
 753     krb5_rd_req_in_ctx_free(context, in);
 754     if (ret)
 755         return ret;
 756
 757     if (ap_req_options)
 758         *ap_req_options = out->ap_req_options;
 759     if (ticket) {
 760         ret = krb5_copy_ticket(context, out->ticket, ticket);
 761         if (ret)
 762             goto out;
 763     }
 764
 765 out:
 766     krb5_rd_req_out_ctx_free(context, out);
 767     return ret;
 768 }
 769
 770 /*
 771  *
 772  */
 773
 774 static krb5_error_code
 775 get_key_from_keytab(krb5_context context,
 776                     krb5_ap_req *ap_req,
 777                     krb5_const_principal server,
 778                     krb5_keytab keytab,
 779                     krb5_keyblock **out_key)
 780 {
 781     krb5_keytab_entry entry;
 782     krb5_error_code ret;
 783     int kvno;
 784     krb5_keytab real_keytab;
 785
 786     if(keytab == NULL)
 787         krb5_kt_default(context, &real_keytab);
 788     else
 789         real_keytab = keytab;
 790
 791     if (ap_req->ticket.enc_part.kvno)
 792         kvno = *ap_req->ticket.enc_part.kvno;
 793     else
 794         kvno = 0;
 795
 796     ret = krb5_kt_get_entry (context,
 797                              real_keytab,
 798                              server,
 799                              kvno,
 800                              ap_req->ticket.enc_part.etype,
 801                              &entry);
 802     if(ret)
 803         goto out;
 804     ret = krb5_copy_keyblock(context, &entry.keyblock, out_key);
 805     krb5_kt_free_entry (context, &entry);
 806 out:
 807     if(keytab == NULL)
 808         krb5_kt_close(context, real_keytab);
 809
 810     return ret;
 811 }
 812
 813 /**
 814  * The core server function that verify application authentication
 815  * requests from clients.
 816  *
 817  * @param context Keberos 5 context.
 818  * @param auth_context the authentication context, can be NULL, then
 819  *        default values for the authentication context will used.
 820  * @param inbuf the (AP-REQ) authentication buffer
 821  *
 822  * @param server the server with authenticate as, if NULL the function
 823  *        will try to find any available credential in the keytab
 824  *        that will verify the reply. The function will prefer the
 825  *        server the server client specified in the AP-REQ, but if
 826  *        there is no mach, it will try all keytab entries for a
 827  *        match. This have serious performance issues for larger keytabs.
 828  *
 829  * @param inctx control the behavior of the function, if NULL, the
 830  *        default behavior is used.
 831  * @param outctx the return outctx, free with krb5_rd_req_out_ctx_free().
 832  * @return Kerberos 5 error code, see krb5_get_error_message().
 833  *
 834  * @ingroup krb5_auth
 835  */
 836
 837 krb5_error_code KRB5_LIB_FUNCTION
 838 krb5_rd_req_ctx(krb5_context context,
 839                 krb5_auth_context *auth_context,
 840                 const krb5_data *inbuf,
 841                 krb5_const_principal server,
 842                 krb5_rd_req_in_ctx inctx,
 843                 krb5_rd_req_out_ctx *outctx)
 844 {
 845     krb5_error_code ret;
 846     krb5_ap_req ap_req;
 847     krb5_rd_req_out_ctx o = NULL;
 848     krb5_keytab id = NULL, keytab = NULL;
 849     krb5_principal service = NULL;
 850
 851     *outctx = NULL;
 852
 853     o = calloc(1, sizeof(*o));
 854     if (o == NULL) {
 855         krb5_set_error_message(context, ENOMEM,
 856                                N_("malloc: out of memory", ""));
 857         return ENOMEM;
 858     }
 859
 860     if (*auth_context == NULL) {
 861         ret = krb5_auth_con_init(context, auth_context);
 862         if (ret)
 863             goto out;
 864     }
 865
 866     ret = krb5_decode_ap_req(context, inbuf, &ap_req);
 867     if(ret)
 868         goto out;
 869
 870     /* Save that principal that was in the request */
 871     ret = _krb5_principalname2krb5_principal(context,
 872                                              &o->server,
 873                                              ap_req.ticket.sname,
 874                                              ap_req.ticket.realm);
 875     if (ret)
 876         goto out;
 877
 878     if (ap_req.ap_options.use_session_key &&
 879         (*auth_context)->keyblock == NULL) {
 880         ret = KRB5KRB_AP_ERR_NOKEY;
 881         krb5_set_error_message(context, ret,
 882                                N_("krb5_rd_req: user to user auth "
 883                                   "without session key given", ""));
 884         goto out;
 885     }
 886
 887     if (inctx && inctx->keytab)
 888         id = inctx->keytab;
 889
 890     if((*auth_context)->keyblock){
 891         ret = krb5_copy_keyblock(context,
 892                                  (*auth_context)->keyblock,
 893                                  &o->keyblock);
 894         if (ret)
 895             goto out;
 896     } else if(inctx && inctx->keyblock){
 897         ret = krb5_copy_keyblock(context,
 898                                  inctx->keyblock,
 899                                  &o->keyblock);
 900         if (ret)
 901             goto out;
 902     } else {
 903
 904         if(id == NULL) {
 905             krb5_kt_default(context, &keytab);
 906             id = keytab;
 907         }
 908         if (id == NULL)
 909             goto out;
 910
 911         if (server == NULL) {
 912             ret = _krb5_principalname2krb5_principal(context,
 913                                                      &service,
 914                                                      ap_req.ticket.sname,
 915                                                      ap_req.ticket.realm);
 916             if (ret)
 917                 goto out;
 918             server = service;
 919         }
 920
 921         ret = get_key_from_keytab(context,
 922                                   &ap_req,
 923                                   server,
 924                                   id,
 925                                   &o->keyblock);
 926         if (ret) {
 927             /* If caller specified a server, fail. */
 928             if (service == NULL)
 929                 goto out;
 930             /* Otherwise, fall back to iterating over the keytab. This
 931              * have serious performace issues for larger keytab.
 932              */
 933             o->keyblock = NULL;
 934         }
 935     }
 936
 937     if (o->keyblock) {
 938         /*
 939          * We got an exact keymatch, use that.
 940          */
 941
 942         ret = krb5_verify_ap_req2(context,
 943                                   auth_context,
 944                                   &ap_req,
 945                                   server,
 946                                   o->keyblock,
 947                                   0,
 948                                   &o->ap_req_options,
 949                                   &o->ticket,
 950                                   KRB5_KU_AP_REQ_AUTH);
 951
 952         if (ret)
 953             goto out;
 954
 955     } else {
 956         /*
 957          * Interate over keytab to find a key that can decrypt the request.
 958          */
 959
 960         krb5_keytab_entry entry;
 961         krb5_kt_cursor cursor;
 962         int done = 0, kvno = 0;
 963
 964         memset(&cursor, 0, sizeof(cursor));
 965
 966         if (ap_req.ticket.enc_part.kvno)
 967             kvno = *ap_req.ticket.enc_part.kvno;
 968
 969         ret = krb5_kt_start_seq_get(context, id, &cursor);
 970         if (ret)
 971             goto out;
 972
 973         done = 0;
 974         while (!done) {
 975             krb5_principal p;
 976
 977             ret = krb5_kt_next_entry(context, id, &entry, &cursor);
 978             if (ret) {
 979                 _krb5_kt_principal_not_found(context, ret, id, o->server,
 980                                              ap_req.ticket.enc_part.etype,
 981                                              kvno);
 982                 goto out;
 983             }
 984
 985             if (entry.keyblock.keytype != ap_req.ticket.enc_part.etype ||
 986                 (kvno && kvno != entry.vno)) {
 987                 krb5_kt_free_entry (context, &entry);
 988                 continue;
 989             }
 990
 991             ret = krb5_verify_ap_req2(context,
 992                                       auth_context,
 993                                       &ap_req,
 994                                       server,
 995                                       &entry.keyblock,
 996                                       0,
 997                                       &o->ap_req_options,
 998                                       &o->ticket,
 999                                       KRB5_KU_AP_REQ_AUTH);
1000             if (ret) {
1001                 krb5_kt_free_entry (context, &entry);
1002                 continue;
1003             }
1004
1005             /*
1006              * Found a match, save the keyblock for PAC processing,
1007              * and update the service principal in the ticket to match
1008              * whatever is in the keytab.
1009              */
1010
1011             ret = krb5_copy_keyblock(context,
1012                                      &entry.keyblock,
1013                                      &o->keyblock);
1014             if (ret) {
1015                 krb5_kt_free_entry (context, &entry);
1016                 goto out;
1017             }
1018
1019             ret = krb5_copy_principal(context, entry.principal, &p);
1020             if (ret) {
1021                 krb5_kt_free_entry (context, &entry);
1022                 goto out;
1023             }
1024             krb5_free_principal(context, o->ticket->server);
1025             o->ticket->server = p;
1026
1027             krb5_kt_free_entry (context, &entry);
1028
1029             done = 1;
1030         }
1031         krb5_kt_end_seq_get (context, id, &cursor);
1032     }
1033
1034     /* If there is a PAC, verify its server signature */
1035     if (inctx == NULL || inctx->check_pac) {
1036         krb5_pac pac;
1037         krb5_data data;
1038
1039         ret = krb5_ticket_get_authorization_data_type(context,
1040                                                       o->ticket,
1041                                                       KRB5_AUTHDATA_WIN2K_PAC,
1042                                                       &data);
1043         if (ret == 0) {
1044             ret = krb5_pac_parse(context, data.data, data.length, &pac);
1045             krb5_data_free(&data);
1046             if (ret)
1047                 goto out;
1048
1049             ret = krb5_pac_verify(context,
1050                                   pac,
1051                                   o->ticket->ticket.authtime,
1052                                   o->ticket->client,
1053                                   o->keyblock,
1054                                   NULL);
1055             krb5_pac_free(context, pac);
1056             if (ret)
1057                 goto out;
1058         } else
1059           ret = 0;
1060     }
1061 out:
1062
1063     if (ret || outctx == NULL) {
1064         krb5_rd_req_out_ctx_free(context, o);
1065     } else
1066         *outctx = o;
1067
1068     free_AP_REQ(&ap_req);
1069
1070     if (service)
1071         krb5_free_principal(context, service);
1072
1073     if (keytab)
1074         krb5_kt_close(context, keytab);
1075
1076     return ret;
1077 }