kdc/fast.c

   1 /*
   2  * Copyright (c) 1997-2011 Kungliga Tekniska Högskolan
   3  * (Royal Institute of Technology, Stockholm, Sweden).
   4  * All rights reserved.
   5  *
   6  * Portions Copyright (c) 2010 - 2011 Apple Inc. All rights reserved.
   7  *
   8  * Redistribution and use in source and binary forms, with or without
   9  * modification, are permitted provided that the following conditions
  10  * are met:
  11  *
  12  * 1. Redistributions of source code must retain the above copyright
  13  *    notice, this list of conditions and the following disclaimer.
  14  *
  15  * 2. Redistributions in binary form must reproduce the above copyright
  16  *    notice, this list of conditions and the following disclaimer in the
  17  *    documentation and/or other materials provided with the distribution.
  18  *
  19  * 3. Neither the name of the Institute nor the names of its contributors
  20  *    may be used to endorse or promote products derived from this software
  21  *    without specific prior written permission.
  22  *
  23  * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
  24  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  25  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  26  * ARE DISCLAIMED.  IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
  27  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  28  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  29  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  30  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  31  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  32  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  33  * SUCH DAMAGE.
  34  */
  35
  36 #include "kdc_locl.h"
  37
  38 static krb5_error_code
  39 salt_fastuser_crypto(astgs_request_t r,
  40                      krb5_const_principal salt_principal,
  41                      krb5_enctype enctype,
  42                      krb5_crypto fast_crypto,
  43                      krb5_crypto *salted_crypto)
  44 {
  45     krb5_error_code ret;
  46     krb5_principal client_princ = NULL;
  47     krb5_data salt;
  48     krb5_keyblock dkey;
  49     size_t size;
  50
  51     *salted_crypto = NULL;
  52
  53     krb5_data_zero(&salt);
  54     krb5_keyblock_zero(&dkey);
  55
  56     if (salt_principal == NULL) {
  57         if (r->req.req_body.cname == NULL) {
  58             ret = KRB5KRB_ERR_GENERIC;
  59             goto out;
  60         }
  61
  62         ret = _krb5_principalname2krb5_principal(r->context, &client_princ,
  63                                                  *(r->req.req_body.cname),
  64                                                  r->req.req_body.realm);
  65         if (ret)
  66             goto out;
  67
  68         salt_principal = client_princ;
  69     }
  70
  71     ret = krb5_unparse_name(r->context, salt_principal, (char **)&salt.data);
  72     if (ret)
  73         goto out;
  74
  75     salt.length = strlen(salt.data);
  76
  77     kdc_log(r->context, r->config, 10,
  78             "salt_fastuser_crypto: salt principal is %s (%d)",
  79             (char *)salt.data, enctype);
  80
  81     ret = krb5_enctype_keysize(r->context, enctype, &size);
  82     if (ret)
  83         goto out;
  84
  85     ret = krb5_crypto_prfplus(r->context, fast_crypto, &salt,
  86                               size, &dkey.keyvalue);
  87     if (ret)
  88         goto out;
  89
  90     dkey.keytype = enctype;
  91
  92     ret = krb5_crypto_init(r->context, &dkey, ENCTYPE_NULL, salted_crypto);
  93     if (ret)
  94         goto out;
  95
  96 out:
  97     krb5_free_keyblock_contents(r->context, &dkey);
  98     krb5_data_free(&salt);
  99     krb5_free_principal(r->context, client_princ);
 100
 101     return ret;
 102 }
 103
 104 static krb5_error_code
 105 get_fastuser_crypto(astgs_request_t r,
 106                     krb5_const_principal ticket_client,
 107                     krb5_enctype enctype,
 108                     krb5_crypto *crypto)
 109 {
 110     krb5_principal fast_princ;
 111     HDB *fast_db;
 112     hdb_entry *fast_user = NULL;
 113     Key *cookie_key = NULL;
 114     krb5_crypto fast_crypto = NULL;
 115     krb5_error_code ret;
 116
 117     *crypto = NULL;
 118
 119     ret = krb5_make_principal(r->context, &fast_princ,
 120                               KRB5_WELLKNOWN_ORG_H5L_REALM,
 121                               KRB5_WELLKNOWN_NAME, "org.h5l.fast-cookie", NULL);
 122     if (ret)
 123         goto out;
 124
 125     ret = _kdc_db_fetch(r->context, r->config, fast_princ,
 126                         HDB_F_GET_FAST_COOKIE, NULL, &fast_db, &fast_user);
 127     if (ret)
 128         goto out;
 129
 130     if (enctype == KRB5_ENCTYPE_NULL)
 131         ret = _kdc_get_preferred_key(r->context, r->config, fast_user,
 132                                      "fast-cookie", &enctype, &cookie_key);
 133     else
 134         ret = hdb_enctype2key(r->context, fast_user, NULL,
 135                               enctype, &cookie_key);
 136     if (ret)
 137         goto out;
 138
 139     ret = krb5_crypto_init(r->context, &cookie_key->key,
 140                            ENCTYPE_NULL, &fast_crypto);
 141     if (ret)
 142         goto out;
 143
 144     ret = salt_fastuser_crypto(r, ticket_client,
 145                                cookie_key->key.keytype,
 146                                fast_crypto, crypto);
 147     if (ret)
 148         goto out;
 149
 150  out:
 151     if (fast_user)
 152         _kdc_free_ent(r->context, fast_db, fast_user);
 153     if (fast_crypto)
 154         krb5_crypto_destroy(r->context, fast_crypto);
 155     krb5_free_principal(r->context, fast_princ);
 156
 157     return ret;
 158 }
 159
 160
 161 static krb5_error_code
 162 fast_parse_cookie(astgs_request_t r,
 163                   krb5_const_principal ticket_client,
 164                   const PA_DATA *pa)
 165 {
 166     krb5_crypto crypto = NULL;
 167     krb5_error_code ret;
 168     KDCFastCookie data;
 169     krb5_data d1;
 170     size_t len;
 171
 172     ret = decode_KDCFastCookie(pa->padata_value.data,
 173                                pa->padata_value.length,
 174                                &data, &len);
 175     if (ret)
 176         return ret;
 177
 178     if (len != pa->padata_value.length || strcmp("H5L1", data.version) != 0) {
 179         free_KDCFastCookie(&data);
 180         return KRB5KDC_ERR_POLICY;
 181     }
 182
 183     ret = get_fastuser_crypto(r, ticket_client, data.cookie.etype, &crypto);
 184     if (ret)
 185         goto out;
 186
 187     ret = krb5_decrypt_EncryptedData(r->context, crypto,
 188                                      KRB5_KU_H5L_COOKIE,
 189                                      &data.cookie, &d1);
 190     krb5_crypto_destroy(r->context, crypto);
 191     if (ret)
 192         goto out;
 193
 194     ret = decode_KDCFastState(d1.data, d1.length, &r->fast, &len);
 195     krb5_data_free(&d1);
 196     if (ret)
 197         goto out;
 198
 199     if (r->fast.expiration < kdc_time) {
 200         kdc_log(r->context, r->config, 2, "FAST cookie expired");
 201         ret = KRB5KDC_ERR_POLICY;
 202         goto out;
 203     }
 204
 205  out:
 206     free_KDCFastCookie(&data);
 207
 208     return ret;
 209 }
 210
 211 static krb5_error_code
 212 fast_add_cookie(astgs_request_t r,
 213                 krb5_const_principal ticket_client,
 214                 METHOD_DATA *method_data)
 215 {
 216     krb5_crypto crypto = NULL;
 217     KDCFastCookie shell;
 218     krb5_error_code ret;
 219     krb5_data data;
 220     size_t size;
 221
 222     memset(&shell, 0, sizeof(shell));
 223
 224     r->fast.expiration = kdc_time + FAST_EXPIRATION_TIME;
 225
 226     ASN1_MALLOC_ENCODE(KDCFastState, data.data, data.length,
 227                        &r->fast, &size, ret);
 228     if (ret)
 229         return ret;
 230     heim_assert(size == data.length, "internal asn.1 encoder error");
 231
 232     ret = get_fastuser_crypto(r, ticket_client, KRB5_ENCTYPE_NULL, &crypto);
 233     if (ret) {
 234         kdc_log(r->context, r->config, 0,
 235                 "Failed to find FAST principal for cookie encryption: %d", ret);
 236         goto out;
 237     }
 238
 239     ret = krb5_encrypt_EncryptedData(r->context, crypto,
 240                                      KRB5_KU_H5L_COOKIE,
 241                                      data.data, data.length, 0,
 242                                      &shell.cookie);
 243     krb5_crypto_destroy(r->context, crypto);
 244     if (ret)
 245         goto out;
 246
 247     krb5_data_free(&data);
 248
 249     shell.version = "H5L1";
 250
 251     ASN1_MALLOC_ENCODE(KDCFastCookie, data.data, data.length,
 252                        &shell, &size, ret);
 253     free_EncryptedData(&shell.cookie);
 254     if (ret)
 255         goto out;
 256     heim_assert(size == data.length, "internal asn.1 encoder error");
 257
 258     ret = krb5_padata_add(r->context, method_data,
 259                           KRB5_PADATA_FX_COOKIE,
 260                           data.data, data.length);
 261     if (ret == 0)
 262         krb5_data_zero(&data);
 263
 264  out:
 265     krb5_data_free(&data);
 266     return ret;
 267 }
 268
 269 krb5_error_code
 270 _kdc_fast_mk_response(krb5_context context,
 271                       krb5_crypto armor_crypto,
 272                       METHOD_DATA *pa_data,
 273                       krb5_keyblock *strengthen_key,
 274                       KrbFastFinished *finished,
 275                       krb5uint32 nonce,
 276                       krb5_data *data)
 277 {
 278     PA_FX_FAST_REPLY fxfastrep;
 279     KrbFastResponse fastrep;
 280     krb5_error_code ret;
 281     krb5_data buf;
 282     size_t size;
 283
 284     memset(&fxfastrep, 0, sizeof(fxfastrep));
 285     memset(&fastrep, 0, sizeof(fastrep));
 286     krb5_data_zero(data);
 287
 288     if (pa_data) {
 289         fastrep.padata.val = pa_data->val;
 290         fastrep.padata.len = pa_data->len;
 291     }
 292     fastrep.strengthen_key = strengthen_key;
 293     fastrep.finished = finished;
 294     fastrep.nonce = nonce;
 295
 296     ASN1_MALLOC_ENCODE(KrbFastResponse, buf.data, buf.length,
 297                        &fastrep, &size, ret);
 298     if (ret)
 299         return ret;
 300     heim_assert(size == buf.length, "internal asn.1 encoder error");
 301
 302     fxfastrep.element = choice_PA_FX_FAST_REPLY_armored_data;
 303
 304     ret = krb5_encrypt_EncryptedData(context,
 305                                      armor_crypto,
 306                                      KRB5_KU_FAST_REP,
 307                                      buf.data,
 308                                      buf.length,
 309                                      0,
 310                                      &fxfastrep.u.armored_data.enc_fast_rep);
 311     krb5_data_free(&buf);
 312     if (ret)
 313         return ret;
 314
 315     ASN1_MALLOC_ENCODE(PA_FX_FAST_REPLY, data->data, data->length,
 316                        &fxfastrep, &size, ret);
 317     free_PA_FX_FAST_REPLY(&fxfastrep);
 318     if (ret)
 319         return ret;
 320     heim_assert(size == data->length, "internal asn.1 encoder error");
 321
 322     return 0;
 323 }
 324
 325
 326 krb5_error_code
 327 _kdc_fast_mk_error(astgs_request_t r,
 328                    METHOD_DATA *error_method,
 329                    krb5_crypto armor_crypto,
 330                    const KDC_REQ_BODY *req_body,
 331                    krb5_error_code outer_error,
 332                    krb5_principal error_client,
 333                    krb5_principal error_server,
 334                    time_t *csec, int *cusec,
 335                    krb5_data *error_msg)
 336 {
 337     krb5_error_code ret;
 338     krb5_data e_data;
 339     size_t size;
 340
 341     krb5_data_zero(&e_data);
 342
 343     heim_assert(r != NULL, "invalid request in _kdc_fast_mk_error");
 344
 345     /*
 346      * FX-COOKIE can be used outside of FAST, e.g. SRP or GSS.
 347      */
 348     if (armor_crypto || r->fast.fast_state.len) {
 349         kdc_log(r->context, r->config, 5, "Adding FAST cookie for KRB-ERROR");
 350         ret = fast_add_cookie(r, error_client, error_method);
 351         if (ret) {
 352             kdc_log(r->context, r->config, 1,
 353                     "Failed to add FAST cookie: %d", ret);
 354             free_METHOD_DATA(error_method);
 355             return ret;
 356         }
 357     }
 358
 359     if (armor_crypto) {
 360         PA_FX_FAST_REPLY fxfastrep;
 361         KrbFastResponse fastrep;
 362
 363         memset(&fxfastrep, 0, sizeof(fxfastrep));
 364         memset(&fastrep, 0, sizeof(fastrep));
 365
 366         kdc_log(r->context, r->config, 5, "Making FAST inner KRB-ERROR");
 367
 368         /* first add the KRB-ERROR to the fast errors */
 369
 370         ret = krb5_mk_error(r->context,
 371                             outer_error,
 372                             r->e_text,
 373                             NULL,
 374                             error_client,
 375                             error_server,
 376                             NULL,
 377                             NULL,
 378                             &e_data);
 379         if (ret) {
 380             kdc_log(r->context, r->config, 1,
 381                     "Failed to make inner KRB-ERROR: %d", ret);
 382             return ret;
 383         }
 384
 385         ret = krb5_padata_add(r->context, error_method,
 386                               KRB5_PADATA_FX_ERROR,
 387                               e_data.data, e_data.length);
 388         if (ret) {
 389             kdc_log(r->context, r->config, 1,
 390                     "Failed to make add FAST PADATA to inner KRB-ERROR: %d", ret);
 391             krb5_data_free(&e_data);
 392             return ret;
 393         }
 394
 395         outer_error = KRB5_KDC_ERR_MORE_PREAUTH_DATA_REQUIRED;
 396         r->e_text = NULL;
 397         if (r->fast.flags.requested_hidden_names) {
 398             error_client = NULL;
 399             error_server = NULL;
 400         }
 401         csec = 0;
 402         cusec = 0;
 403
 404         ret = _kdc_fast_mk_response(r->context, armor_crypto,
 405                                     error_method, NULL, NULL,
 406                                     req_body->nonce, &e_data);
 407         free_METHOD_DATA(error_method);
 408         if (ret) {
 409             kdc_log(r->context, r->config, 1,
 410                     "Failed to make outer KRB-ERROR: %d", ret);
 411             return ret;
 412         }
 413
 414         ret = krb5_padata_add(r->context, error_method,
 415                               KRB5_PADATA_FX_FAST,
 416                               e_data.data, e_data.length);
 417         if (ret) {
 418             kdc_log(r->context, r->config, 1,
 419                     "Failed to make add FAST PADATA to outer KRB-ERROR: %d", ret);
 420             return ret;
 421         }
 422     } else
 423         kdc_log(r->context, r->config, 5, "Making non-FAST KRB-ERROR");
 424
 425     if (error_method && error_method->len) {
 426         ASN1_MALLOC_ENCODE(METHOD_DATA, e_data.data, e_data.length,
 427                            error_method, &size, ret);
 428         if (ret) {
 429             kdc_log(r->context, r->config, 1,
 430                     "Failed to make encode METHOD-DATA: %d", ret);
 431             return ret;
 432         }
 433         heim_assert(size == e_data.length, "internal asn.1 encoder error");
 434     }
 435
 436     ret = krb5_mk_error(r->context,
 437                         outer_error,
 438                         r->e_text,
 439                         (e_data.length ? &e_data : NULL),
 440                         error_client,
 441                         error_server,
 442                         csec,
 443                         cusec,
 444                         error_msg);
 445     krb5_data_free(&e_data);
 446
 447     if (ret)
 448         kdc_log(r->context, r->config, 1,
 449                 "Failed to make encode KRB-ERROR: %d", ret);
 450
 451     return ret;
 452 }
 453
 454 static krb5_error_code
 455 fast_unwrap_request(astgs_request_t r,
 456                     krb5_ticket *tgs_ticket,
 457                     krb5_auth_context tgs_ac)
 458 {
 459     krb5_principal armor_server_principal = NULL;
 460     char *armor_client_principal_name = NULL;
 461     char *armor_server_principal_name = NULL;
 462     PA_FX_FAST_REQUEST fxreq;
 463     krb5_auth_context ac = NULL;
 464     krb5_ticket *ticket = NULL;
 465     krb5_flags ap_req_options;
 466     krb5_keyblock armorkey;
 467     krb5_keyblock explicit_armorkey;
 468     krb5_error_code ret;
 469     krb5_ap_req ap_req;
 470     KrbFastReq fastreq;
 471     const PA_DATA *pa;
 472     krb5_data data;
 473     size_t len;
 474     int i = 0;
 475
 476     memset(&fxreq, 0, sizeof(fxreq));
 477     memset(&fastreq, 0, sizeof(fastreq));
 478
 479     pa = _kdc_find_padata(&r->req, &i, KRB5_PADATA_FX_FAST);
 480     if (pa == NULL) {
 481         if (tgs_ac && r->fast_asserted) {
 482             kdc_log(r->context, r->config, 1,
 483                     "Client asserted FAST but did not include FX-FAST pa-data");
 484             ret = KRB5KRB_AP_ERR_MODIFIED;
 485             goto out;
 486         }
 487
 488         kdc_log(r->context, r->config, 10, "Not a FAST request");
 489         return 0;
 490     }
 491
 492     ret = decode_PA_FX_FAST_REQUEST(pa->padata_value.data,
 493                                     pa->padata_value.length,
 494                                     &fxreq,
 495                                     &len);
 496     if (ret) {
 497         kdc_log(r->context, r->config, 4,
 498                 "Failed to decode PA-FX-FAST-REQUEST: %d", ret);
 499         goto out;
 500     }
 501
 502     if (fxreq.element != choice_PA_FX_FAST_REQUEST_armored_data) {
 503         kdc_log(r->context, r->config, 4,
 504                 "PA-FX-FAST-REQUEST contains unknown type: %d",
 505                 (int)fxreq.element);
 506         ret = KRB5KDC_ERR_PREAUTH_FAILED;
 507         goto out;
 508     }
 509
 510     /*
 511      * If check for armor data or it's not a TGS-REQ with implicit
 512      * armor.
 513      */
 514     if (fxreq.u.armored_data.armor == NULL && tgs_ac == NULL) {
 515         kdc_log(r->context, r->config, 4,
 516                 "AS-REQ armor missing");
 517         ret = KRB5KDC_ERR_PREAUTH_FAILED;
 518         goto out;
 519     }
 520
 521     r->explicit_armor_present = fxreq.u.armored_data.armor != NULL && tgs_ac != NULL;
 522
 523     /*
 524      *
 525      */
 526     if (fxreq.u.armored_data.armor != NULL) {
 527         if (fxreq.u.armored_data.armor->armor_type != 1) {
 528             kdc_log(r->context, r->config, 4,
 529                     "Incorrect AS-REQ armor type");
 530             ret = KRB5KDC_ERR_PREAUTH_FAILED;
 531             goto out;
 532         }
 533
 534         ret = krb5_decode_ap_req(r->context,
 535                                  &fxreq.u.armored_data.armor->armor_value,
 536                                  &ap_req);
 537         if(ret) {
 538             kdc_log(r->context, r->config, 4, "Failed to decode AP-REQ");
 539             goto out;
 540         }
 541
 542         /* Save that principal that was in the request */
 543         ret = _krb5_principalname2krb5_principal(r->context,
 544                                                  &armor_server_principal,
 545                                                  ap_req.ticket.sname,
 546                                                  ap_req.ticket.realm);
 547         if (ret) {
 548             free_AP_REQ(&ap_req);
 549             goto out;
 550         }
 551
 552         ret = _kdc_db_fetch(r->context, r->config, armor_server_principal,
 553                             HDB_F_GET_KRBTGT | HDB_F_DELAY_NEW_KEYS,
 554                             (krb5uint32 *)ap_req.ticket.enc_part.kvno,
 555                             &r->armor_serverdb, &r->armor_server);
 556         if(ret == HDB_ERR_NOT_FOUND_HERE) {
 557             free_AP_REQ(&ap_req);
 558             kdc_log(r->context, r->config, 5,
 559                     "Armor key does not have secrets at this KDC, "
 560                     "need to proxy");
 561             goto out;
 562         } else if (ret) {
 563             free_AP_REQ(&ap_req);
 564             ret = KRB5KDC_ERR_S_PRINCIPAL_UNKNOWN;
 565             goto out;
 566         }
 567
 568         ret = hdb_enctype2key(r->context, r->armor_server, NULL,
 569                               ap_req.ticket.enc_part.etype,
 570                               &r->armor_key);
 571         if (ret) {
 572             free_AP_REQ(&ap_req);
 573             goto out;
 574         }
 575
 576         ret = krb5_verify_ap_req2(r->context, &ac,
 577                                   &ap_req,
 578                                   armor_server_principal,
 579                                   &r->armor_key->key,
 580                                   0,
 581                                   &ap_req_options,
 582                                   &r->armor_ticket,
 583                                   KRB5_KU_AP_REQ_AUTH);
 584         free_AP_REQ(&ap_req);
 585         if (ret)
 586             goto out;
 587
 588         ret = krb5_unparse_name(r->context, armor_server_principal,
 589                                 &armor_server_principal_name);
 590         if (ret)
 591             goto out;
 592
 593         /* FIXME krb5_verify_ap_req2() also checks this */
 594         ret = _kdc_verify_flags(r->context, r->config,
 595                                 &r->armor_ticket->ticket,
 596                                 armor_server_principal_name);
 597         if (ret) {
 598             kdc_audit_addreason((kdc_request_t)r,
 599                                 "Armor TGT expired or invalid");
 600             goto out;
 601         }
 602         ticket = r->armor_ticket;
 603     } else {
 604         heim_assert(tgs_ticket != NULL, "TGS authentication context without ticket");
 605         ac = tgs_ac;
 606         ticket = tgs_ticket;
 607     }
 608
 609     krb5_unparse_name(r->context, ticket->client, &armor_client_principal_name);
 610     kdc_audit_addkv((kdc_request_t)r, 0, "armor_client_name", "%s",
 611                     armor_client_principal_name ? armor_client_principal_name : "<unknown>");
 612
 613     if (ac->remote_subkey == NULL) {
 614         krb5_auth_con_free(r->context, ac);
 615         kdc_log(r->context, r->config, 2,
 616                 "FAST AP-REQ remote subkey missing");
 617         ret = KRB5KDC_ERR_PREAUTH_FAILED;
 618         goto out;
 619     }
 620
 621     r->fast.flags.kdc_verified =
 622         !_kdc_is_anonymous_pkinit(r->context, ticket->client);
 623
 624     ret = _krb5_fast_armor_key(r->context,
 625                                ac->remote_subkey,
 626                                &ticket->ticket.key,
 627                                &armorkey,
 628                                r->explicit_armor_present ? NULL : &r->armor_crypto);
 629     if (ret)
 630         goto out;
 631
 632     if (r->explicit_armor_present) {
 633         ret = _krb5_fast_explicit_armor_key(r->context,
 634                                             &armorkey,
 635                                             tgs_ac->remote_subkey,
 636                                             &explicit_armorkey,
 637                                             &r->armor_crypto);
 638         if (ret)
 639             goto out;
 640
 641         krb5_free_keyblock_contents(r->context, &explicit_armorkey);
 642     }
 643
 644     krb5_free_keyblock_contents(r->context, &armorkey);
 645
 646     ret = krb5_decrypt_EncryptedData(r->context, r->armor_crypto,
 647                                      KRB5_KU_FAST_ENC,
 648                                      &fxreq.u.armored_data.enc_fast_req,
 649                                      &data);
 650     if (ret) {
 651         kdc_log(r->context, r->config, 2,
 652                 "Failed to decrypt FAST request");
 653         goto out;
 654     }
 655
 656     ret = decode_KrbFastReq(data.data, data.length, &fastreq, NULL);
 657     krb5_data_free(&data);
 658     if (ret)
 659         goto out;
 660
 661     /*
 662      * verify req-checksum of the outer body
 663      */
 664     if (tgs_ac) {
 665         /*
 666          * -- For TGS, contains the checksum performed over the type
 667          * -- AP-REQ in the PA-TGS-REQ padata.
 668          */
 669         i = 0;
 670         pa = _kdc_find_padata(&r->req, &i, KRB5_PADATA_TGS_REQ);
 671         if (pa == NULL) {
 672             kdc_log(r->context, r->config, 4,
 673                     "FAST TGS request missing TGS-REQ padata");
 674             ret = KRB5KRB_ERR_GENERIC;
 675             goto out;
 676         }
 677
 678         ret = _kdc_verify_checksum(r->context, r->armor_crypto,
 679                                    KRB5_KU_FAST_REQ_CHKSUM,
 680                                    &pa->padata_value,
 681                                    &fxreq.u.armored_data.req_checksum);
 682         if (ret) {
 683             kdc_log(r->context, r->config, 2,
 684                     "Bad checksum in FAST TGS request");
 685             goto out;
 686         }
 687     } else {
 688         /*
 689          * -- For AS, contains the checksum performed over the type
 690          * -- KDC-REQ-BODY for the req-body field of the KDC-REQ
 691          * -- structure;
 692          */
 693         ret = _kdc_verify_checksum(r->context, r->armor_crypto,
 694                                    KRB5_KU_FAST_REQ_CHKSUM,
 695                                    &r->req.req_body._save,
 696                                    &fxreq.u.armored_data.req_checksum);
 697         if (ret) {
 698             kdc_log(r->context, r->config, 2,
 699                     "Bad checksum in FAST AS request");
 700             goto out;
 701         }
 702     }
 703
 704     /*
 705      * check for unsupported mandatory options
 706      */
 707     if (FastOptions2int(fastreq.fast_options) & 0xfffc) {
 708         kdc_log(r->context, r->config, 2,
 709                 "FAST unsupported mandatory option set");
 710         ret = KRB5_KDC_ERR_UNKNOWN_CRITICAL_FAST_OPTIONS;
 711         goto out;
 712     }
 713
 714     r->fast.flags.requested_hidden_names = fastreq.fast_options.hide_client_names;
 715
 716     /* KDC MUST ignore outer pa data preauth-14 - 6.5.5 */
 717     if (r->req.padata)
 718         free_METHOD_DATA(r->req.padata);
 719     else
 720         ALLOC(r->req.padata);
 721
 722     ret = copy_METHOD_DATA(&fastreq.padata, r->req.padata);
 723     if (ret)
 724         goto out;
 725
 726     free_KDC_REQ_BODY(&r->req.req_body);
 727     ret = copy_KDC_REQ_BODY(&fastreq.req_body, &r->req.req_body);
 728     if (ret)
 729         goto out;
 730
 731     kdc_log(r->context, r->config, 5, "Client selected FAST");
 732
 733  out:
 734     if (ac && ac != tgs_ac)
 735         krb5_auth_con_free(r->context, ac);
 736
 737     krb5_free_principal(r->context, armor_server_principal);
 738     krb5_xfree(armor_client_principal_name);
 739     krb5_xfree(armor_server_principal_name);
 740
 741     free_KrbFastReq(&fastreq);
 742     free_PA_FX_FAST_REQUEST(&fxreq);
 743
 744     return ret;
 745 }
 746
 747 /*
 748  *
 749  */
 750 krb5_error_code
 751 _kdc_fast_unwrap_request(astgs_request_t r,
 752                          krb5_ticket *tgs_ticket,
 753                          krb5_auth_context tgs_ac)
 754 {
 755     krb5_error_code ret;
 756     const PA_DATA *pa;
 757     int i = 0;
 758
 759     if (!r->config->enable_fast)
 760         return 0;
 761
 762     ret = fast_unwrap_request(r, tgs_ticket, tgs_ac);
 763     if (ret)
 764         return ret;
 765
 766     /*
 767      * FX-COOKIE can be used outside of FAST, e.g. SRP or GSS.
 768      */
 769     pa = _kdc_find_padata(&r->req, &i, KRB5_PADATA_FX_COOKIE);
 770     if (pa) {
 771         krb5_const_principal ticket_client = NULL;
 772
 773         if (tgs_ticket)
 774             ticket_client = tgs_ticket->client;
 775
 776         ret = fast_parse_cookie(r, ticket_client, pa);
 777     }
 778
 779     return ret;
 780 }
 781
 782 /*
 783  * Strengthen reply key by mixing with a random key that is
 784  * protected by FAST.
 785  */
 786 krb5_error_code
 787 _kdc_fast_strengthen_reply_key(astgs_request_t r)
 788 {
 789     if (r->armor_crypto) {
 790         krb5_keyblock new_reply_key;
 791         krb5_error_code ret;
 792
 793         kdc_log(r->context, r->config, 5,
 794                 "FAST strengthen reply key with strengthen-key");
 795
 796         heim_assert(r->reply_key.keytype != KRB5_ENCTYPE_NULL, "NULL reply key enctype");
 797
 798         ret = krb5_generate_random_keyblock(r->context, r->reply_key.keytype,
 799                                             &r->strengthen_key);
 800         if (ret)
 801             krb5_abortx(r->context, "random generator fail");
 802
 803         ret = _krb5_fast_cf2(r->context,
 804                              &r->strengthen_key, "strengthenkey",
 805                              &r->reply_key, "replykey",
 806                              &new_reply_key, NULL);
 807         if (ret)
 808             return ret;
 809
 810         krb5_free_keyblock_contents(r->context, &r->reply_key);
 811         r->reply_key = new_reply_key;
 812     }
 813
 814     return 0;
 815 }
 816
 817 /*
 818  * Zero and free KDCFastState
 819  */
 820 void
 821 _kdc_free_fast_state(KDCFastState *state)
 822 {
 823     size_t i;
 824
 825     for (i = 0; i < state->fast_state.len; i++) {
 826         PA_DATA *pa = &state->fast_state.val[i];
 827
 828         if (pa->padata_value.data)
 829             memset_s(pa->padata_value.data, 0,
 830                      pa->padata_value.length, pa->padata_value.length);
 831     }
 832     free_KDCFastState(state);
 833 }
 834
 835 krb5_error_code
 836 _kdc_fast_check_armor_pac(astgs_request_t r)
 837 {
 838     krb5_error_code ret;
 839     int flags;
 840     krb5_boolean ad_kdc_issued = FALSE;
 841     krb5_pac mspac = NULL;
 842     krb5_principal armor_client_principal = NULL;
 843     HDB *armor_db;
 844     hdb_entry *armor_client = NULL;
 845     char *armor_client_principal_name = NULL;
 846
 847     flags = HDB_F_FOR_TGS_REQ;
 848     if (_kdc_synthetic_princ_used_p(r->context, r->armor_ticket))
 849         flags |= HDB_F_SYNTHETIC_OK;
 850     if (r->req.req_body.kdc_options.canonicalize)
 851         flags |= HDB_F_CANON;
 852
 853     ret = _krb5_principalname2krb5_principal(r->context,
 854                                              &armor_client_principal,
 855                                              r->armor_ticket->ticket.cname,
 856                                              r->armor_ticket->ticket.crealm);
 857     if (ret)
 858         goto out;
 859
 860     ret = krb5_unparse_name(r->context, armor_client_principal,
 861                             &armor_client_principal_name);
 862     if (ret)
 863         goto out;
 864
 865     ret = _kdc_db_fetch_client(r->context, r->config, flags,
 866                                armor_client_principal, armor_client_principal_name,
 867                                r->req.req_body.realm, &armor_db, &armor_client);
 868     if (ret)
 869         goto out;
 870
 871     ret = kdc_check_flags(r, FALSE, armor_client, NULL);
 872     if (ret)
 873         goto out;
 874
 875     ret = _kdc_check_pac(r, armor_client_principal, NULL,
 876                          armor_client, r->armor_server,
 877                          r->armor_server, r->armor_server,
 878                          &r->armor_key->key, &r->armor_key->key,
 879                          &r->armor_ticket->ticket, &ad_kdc_issued, &mspac, NULL, NULL);
 880     if (ret) {
 881         const char *msg = krb5_get_error_message(r->context, ret);
 882
 883         kdc_log(r->context, r->config, 4,
 884                 "Verify armor PAC (%s) failed for %s (%s) from %s with %s (%s)",
 885                 armor_client_principal_name, r->cname, r->sname,
 886                 r->from, msg, mspac ? "Ticket unsigned" : "No PAC");
 887
 888         krb5_free_error_message(r->context, msg);
 889
 890         goto out;
 891     }
 892
 893     if (r->explicit_armor_present) {
 894         r->explicit_armor_clientdb = armor_db;
 895         armor_db = NULL;
 896
 897         r->explicit_armor_client = armor_client;
 898         armor_client = NULL;
 899
 900         r->explicit_armor_pac = mspac;
 901         mspac = NULL;
 902     }
 903
 904 out:
 905     krb5_xfree(armor_client_principal_name);
 906     if (armor_client)
 907         _kdc_free_ent(r->context, armor_db, armor_client);
 908     krb5_free_principal(r->context, armor_client_principal);
 909     krb5_pac_free(r->context, mspac);
 910
 911     return ret;
 912 }