source3/libads/kerberos_keytab.c

   1 /*
   2    Unix SMB/CIFS implementation.
   3    kerberos keytab utility library
   4    Copyright (C) Andrew Tridgell 2001
   5    Copyright (C) Remus Koos 2001
   6    Copyright (C) Luke Howard 2003
   7    Copyright (C) Jim McDonough (jmcd@us.ibm.com) 2003
   8    Copyright (C) Guenther Deschner 2003
   9    Copyright (C) Rakesh Patel 2004
  10    Copyright (C) Dan Perry 2004
  11    Copyright (C) Jeremy Allison 2004
  12    Copyright (C) Gerald Carter 2006
  13
  14    This program is free software; you can redistribute it and/or modify
  15    it under the terms of the GNU General Public License as published by
  16    the Free Software Foundation; either version 3 of the License, or
  17    (at your option) any later version.
  18
  19    This program is distributed in the hope that it will be useful,
  20    but WITHOUT ANY WARRANTY; without even the implied warranty of
  21    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  22    GNU General Public License for more details.
  23
  24    You should have received a copy of the GNU General Public License
  25    along with this program.  If not, see <http://www.gnu.org/licenses/>.
  26 */
  27
  28 #include "includes.h"
  29 #include "smb_krb5.h"
  30 #include "ads.h"
  31 #include "secrets.h"
  32
  33 #ifdef HAVE_KRB5
  34
  35 #ifdef HAVE_ADS
  36
  37 /* This MAX_NAME_LEN is a constant defined in krb5.h */
  38 #ifndef MAX_KEYTAB_NAME_LEN
  39 #define MAX_KEYTAB_NAME_LEN 1100
  40 #endif
  41
  42 static krb5_error_code ads_keytab_open(krb5_context context,
  43                                        krb5_keytab *keytab)
  44 {
  45         char keytab_str[MAX_KEYTAB_NAME_LEN] = {0};
  46         const char *keytab_name = NULL;
  47         krb5_error_code ret = 0;
  48
  49         switch (lp_kerberos_method()) {
  50         case KERBEROS_VERIFY_SYSTEM_KEYTAB:
  51         case KERBEROS_VERIFY_SECRETS_AND_KEYTAB:
  52                 ret = krb5_kt_default_name(context,
  53                                            keytab_str,
  54                                            sizeof(keytab_str) - 2);
  55                 if (ret != 0) {
  56                         DBG_WARNING("Failed to get default keytab name");
  57                         goto out;
  58                 }
  59                 keytab_name = keytab_str;
  60                 break;
  61         case KERBEROS_VERIFY_DEDICATED_KEYTAB:
  62                 keytab_name = lp_dedicated_keytab_file();
  63                 break;
  64         default:
  65                 DBG_ERR("Invalid kerberos method set (%d)\n",
  66                         lp_kerberos_method());
  67                 ret = KRB5_KT_BADNAME;
  68                 goto out;
  69         }
  70
  71         if (keytab_name == NULL || keytab_name[0] == '\0') {
  72                 DBG_ERR("Invalid keytab name\n");
  73                 ret = KRB5_KT_BADNAME;
  74                 goto out;
  75         }
  76
  77         ret = smb_krb5_kt_open(context, keytab_name, true, keytab);
  78         if (ret != 0) {
  79                 DBG_WARNING("smb_krb5_kt_open failed (%s)\n",
  80                             error_message(ret));
  81                 goto out;
  82         }
  83
  84 out:
  85         return ret;
  86 }
  87
  88 static bool fill_default_spns(TALLOC_CTX *ctx, const char *machine_name,
  89                                           const char *my_fqdn, const char *spn,
  90                                           const char ***spns)
  91 {
  92         char *psp1, *psp2;
  93
  94         if (*spns == NULL) {
  95                 *spns = talloc_zero_array(ctx, const char*, 3);
  96                 if (*spns == NULL) {
  97                         return false;
  98                 }
  99         }
 100
 101         psp1 = talloc_asprintf(ctx,
 102                                "%s/%s",
 103                                spn,
 104                                machine_name);
 105         if (psp1 == NULL) {
 106                 return false;
 107         }
 108
 109         if (!strlower_m(&psp1[strlen(spn) + 1])) {
 110                 return false;
 111         }
 112         (*spns)[0] = psp1;
 113
 114         psp2 = talloc_asprintf(ctx,
 115                                "%s/%s",
 116                                spn,
 117                                my_fqdn);
 118         if (psp2 == NULL) {
 119                 return false;
 120         }
 121
 122         if (!strlower_m(&psp2[strlen(spn) + 1])) {
 123                 return false;
 124         }
 125
 126         (*spns)[1] = psp2;
 127
 128         return true;
 129 }
 130
 131 static bool ads_set_machine_account_spns(TALLOC_CTX *ctx,
 132                                          ADS_STRUCT *ads,
 133                                          const char *service_or_spn,
 134                                          const char *my_fqdn)
 135 {
 136         const char **spn_names = NULL;
 137         ADS_STATUS aderr;
 138         struct spn_struct* spn_struct = NULL;
 139         char *tmp = NULL;
 140
 141         /* SPN should have '/' */
 142         tmp = strchr_m(service_or_spn, '/');
 143         if (tmp != NULL) {
 144                 spn_struct = parse_spn(ctx, service_or_spn);
 145                 if (spn_struct == NULL) {
 146                         return false;
 147                 }
 148         }
 149
 150         DBG_INFO("Attempting to add/update '%s'\n", service_or_spn);
 151
 152         if (spn_struct != NULL) {
 153                 spn_names = talloc_zero_array(ctx, const char*, 2);
 154                 spn_names[0] = service_or_spn;
 155         } else {
 156                 bool ok;
 157
 158                 ok = fill_default_spns(ctx,
 159                                        lp_netbios_name(),
 160                                        my_fqdn,
 161                                        service_or_spn,
 162                                        &spn_names);
 163                 if (!ok) {
 164                         return false;
 165                 }
 166         }
 167         aderr = ads_add_service_principal_names(ads,
 168                                                 lp_netbios_name(),
 169                                                 spn_names);
 170         if (!ADS_ERR_OK(aderr)) {
 171                 DBG_WARNING("Failed to add service principal name.\n");
 172                 return false;
 173         }
 174
 175         return true;
 176 }
 177
 178 /*
 179  * Create kerberos principal(s) from SPN or service name.
 180  */
 181 static bool service_or_spn_to_kerberos_princ(TALLOC_CTX *ctx,
 182                                              const char *service_or_spn,
 183                                              const char *my_fqdn,
 184                                              char **p_princ_s,
 185                                              char **p_short_princ_s)
 186 {
 187         char *princ_s = NULL;
 188         char *short_princ_s = NULL;
 189         const char *service = service_or_spn;
 190         const char *host = my_fqdn;
 191         struct spn_struct* spn_struct = NULL;
 192         char *tmp = NULL;
 193         bool ok = true;
 194
 195         /* SPN should have '/' */
 196         tmp = strchr_m(service_or_spn, '/');
 197         if (tmp != NULL) {
 198                 spn_struct = parse_spn(ctx, service_or_spn);
 199                 if (spn_struct == NULL) {
 200                         ok = false;
 201                         goto out;
 202                 }
 203         }
 204         if (spn_struct != NULL) {
 205                 service = spn_struct->serviceclass;
 206                 host = spn_struct->host;
 207         }
 208         princ_s = talloc_asprintf(ctx, "%s/%s@%s",
 209                                   service,
 210                                   host, lp_realm());
 211         if (princ_s == NULL) {
 212                 ok = false;
 213                 goto out;
 214         }
 215
 216         if (spn_struct == NULL) {
 217                 short_princ_s = talloc_asprintf(ctx, "%s/%s@%s",
 218                                         service, lp_netbios_name(),
 219                                         lp_realm());
 220                 if (short_princ_s == NULL) {
 221                         ok = false;
 222                         goto out;
 223                 }
 224         }
 225         *p_princ_s = princ_s;
 226         *p_short_princ_s = short_princ_s;
 227 out:
 228         return ok;
 229 }
 230
 231 static int add_kt_entry_etypes(krb5_context context, TALLOC_CTX *tmpctx,
 232                                ADS_STRUCT *ads, const char *salt_princ_s,
 233                                krb5_keytab keytab, krb5_kvno kvno,
 234                                const char *srvPrinc, const char *my_fqdn,
 235                                krb5_data *password, bool update_ads)
 236 {
 237         krb5_error_code ret = 0;
 238         char *princ_s = NULL;
 239         char *short_princ_s = NULL;
 240         krb5_enctype enctypes[4] = {
 241                 ENCTYPE_AES256_CTS_HMAC_SHA1_96,
 242                 ENCTYPE_AES128_CTS_HMAC_SHA1_96,
 243                 ENCTYPE_ARCFOUR_HMAC,
 244                 0
 245         };
 246         size_t i;
 247
 248         /* Construct our principal */
 249         if (strchr_m(srvPrinc, '@')) {
 250                 /* It's a fully-named principal. */
 251                 princ_s = talloc_asprintf(tmpctx, "%s", srvPrinc);
 252                 if (!princ_s) {
 253                         ret = -1;
 254                         goto out;
 255                 }
 256         } else if (srvPrinc[strlen(srvPrinc)-1] == '$') {
 257                 /* It's the machine account, as used by smbclient clients. */
 258                 princ_s = talloc_asprintf(tmpctx, "%s@%s",
 259                                           srvPrinc, lp_realm());
 260                 if (!princ_s) {
 261                         ret = -1;
 262                         goto out;
 263                 }
 264         } else {
 265                 /* It's a normal service principal.  Add the SPN now so that we
 266                  * can obtain credentials for it and double-check the salt value
 267                  * used to generate the service's keys. */
 268
 269                 if (!service_or_spn_to_kerberos_princ(tmpctx,
 270                                                       srvPrinc,
 271                                                       my_fqdn,
 272                                                       &princ_s,
 273                                                       &short_princ_s)) {
 274                         ret = -1;
 275                         goto out;
 276                 }
 277
 278                 /* According to http://support.microsoft.com/kb/326985/en-us,
 279                    certain principal names are automatically mapped to the
 280                    host/... principal in the AD account.
 281                    So only create these in the keytab, not in AD.  --jerry */
 282
 283                 if (update_ads && !strequal(srvPrinc, "cifs") &&
 284                     !strequal(srvPrinc, "host")) {
 285                         if (!ads_set_machine_account_spns(tmpctx,
 286                                                           ads,
 287                                                           srvPrinc,
 288                                                           my_fqdn)) {
 289                                 ret = -1;
 290                                 goto out;
 291                         }
 292                 }
 293         }
 294
 295         for (i = 0; enctypes[i]; i++) {
 296
 297                 /* add the fqdn principal to the keytab */
 298                 ret = smb_krb5_kt_add_entry(context,
 299                                             keytab,
 300                                             kvno,
 301                                             princ_s,
 302                                             salt_princ_s,
 303                                             enctypes[i],
 304                                             password,
 305                                             false); /* no_salt */
 306                 if (ret) {
 307                         DBG_WARNING("Failed to add entry to keytab\n");
 308                         goto out;
 309                 }
 310
 311                 /* add the short principal name if we have one */
 312                 if (short_princ_s) {
 313                         ret = smb_krb5_kt_add_entry(context,
 314                                                     keytab,
 315                                                     kvno,
 316                                                     short_princ_s,
 317                                                     salt_princ_s,
 318                                                     enctypes[i],
 319                                                     password,
 320                                                     false); /* no_salt */
 321                         if (ret) {
 322                                 DBG_WARNING("Failed to add short entry to keytab\n");
 323                                 goto out;
 324                         }
 325                 }
 326         }
 327 out:
 328         return ret;
 329 }
 330
 331 /**********************************************************************
 332  Adds a single service principal, i.e. 'host' to the system keytab
 333 ***********************************************************************/
 334
 335 int ads_keytab_add_entry(ADS_STRUCT *ads, const char *srvPrinc, bool update_ads)
 336 {
 337         krb5_error_code ret = 0;
 338         krb5_context context = NULL;
 339         krb5_keytab keytab = NULL;
 340         krb5_data password;
 341         krb5_kvno kvno;
 342         char *salt_princ_s = NULL;
 343         char *password_s = NULL;
 344         char *my_fqdn;
 345         TALLOC_CTX *tmpctx = NULL;
 346         char **hostnames_array = NULL;
 347         size_t num_hostnames = 0;
 348
 349         ret = smb_krb5_init_context_common(&context);
 350         if (ret) {
 351                 DBG_ERR("kerberos init context failed (%s)\n",
 352                         error_message(ret));
 353                 return -1;
 354         }
 355
 356         ret = ads_keytab_open(context, &keytab);
 357         if (ret != 0) {
 358                 goto out;
 359         }
 360
 361         /* retrieve the password */
 362         if (!secrets_init()) {
 363                 DBG_WARNING("secrets_init failed\n");
 364                 ret = -1;
 365                 goto out;
 366         }
 367         password_s = secrets_fetch_machine_password(lp_workgroup(), NULL, NULL);
 368         if (!password_s) {
 369                 DBG_WARNING("failed to fetch machine password\n");
 370                 ret = -1;
 371                 goto out;
 372         }
 373         ZERO_STRUCT(password);
 374         password.data = password_s;
 375         password.length = strlen(password_s);
 376
 377         /* we need the dNSHostName value here */
 378         tmpctx = talloc_init(__location__);
 379         if (!tmpctx) {
 380                 DBG_ERR("talloc_init() failed!\n");
 381                 ret = -1;
 382                 goto out;
 383         }
 384
 385         my_fqdn = ads_get_dnshostname(ads, tmpctx, lp_netbios_name());
 386         if (!my_fqdn) {
 387                 DBG_ERR("unable to determine machine account's dns name in "
 388                         "AD!\n");
 389                 ret = -1;
 390                 goto out;
 391         }
 392
 393         /* make sure we have a single instance of a the computer account */
 394         if (!ads_has_samaccountname(ads, tmpctx, lp_netbios_name())) {
 395                 DBG_ERR("unable to determine machine account's short name in "
 396                         "AD!\n");
 397                 ret = -1;
 398                 goto out;
 399         }
 400
 401         kvno = (krb5_kvno)ads_get_machine_kvno(ads, lp_netbios_name());
 402         if (kvno == -1) {
 403                 /* -1 indicates failure, everything else is OK */
 404                 DBG_WARNING("ads_get_machine_kvno failed to determine the "
 405                             "system's kvno.\n");
 406                 ret = -1;
 407                 goto out;
 408         }
 409
 410         salt_princ_s = kerberos_secrets_fetch_salt_princ();
 411         if (salt_princ_s == NULL) {
 412                 DBG_WARNING("kerberos_secrets_fetch_salt_princ() failed\n");
 413                 ret = -1;
 414                 goto out;
 415         }
 416
 417         ret = add_kt_entry_etypes(context, tmpctx, ads, salt_princ_s, keytab,
 418                                   kvno, srvPrinc, my_fqdn, &password,
 419                                   update_ads);
 420         if (ret != 0) {
 421                 goto out;
 422         }
 423
 424         if (ADS_ERR_OK(ads_get_additional_dns_hostnames(tmpctx, ads,
 425                                                         lp_netbios_name(),
 426                                                         &hostnames_array,
 427                                                         &num_hostnames))) {
 428                 size_t i;
 429
 430                 for (i = 0; i < num_hostnames; i++) {
 431
 432                         ret = add_kt_entry_etypes(context, tmpctx, ads,
 433                                                   salt_princ_s, keytab,
 434                                                   kvno, srvPrinc,
 435                                                   hostnames_array[i],
 436                                                   &password, update_ads);
 437                         if (ret != 0) {
 438                                 goto out;
 439                         }
 440                 }
 441         }
 442
 443 out:
 444         SAFE_FREE(salt_princ_s);
 445         TALLOC_FREE(tmpctx);
 446
 447         if (keytab) {
 448                 krb5_kt_close(context, keytab);
 449         }
 450         if (context) {
 451                 krb5_free_context(context);
 452         }
 453         return (int)ret;
 454 }
 455
 456 /**********************************************************************
 457  Delete a single service principal, i.e. 'host' from the system keytab
 458 ***********************************************************************/
 459
 460 int ads_keytab_delete_entry(ADS_STRUCT *ads, const char *srvPrinc)
 461 {
 462         TALLOC_CTX *frame = talloc_stackframe();
 463         krb5_error_code ret = 0;
 464         krb5_context context = NULL;
 465         krb5_keytab keytab = NULL;
 466         char *princ_s = NULL;
 467         krb5_principal princ = NULL;
 468         char *short_princ_s = NULL;
 469         krb5_principal short_princ = NULL;
 470         bool ok;
 471
 472         ret = smb_krb5_init_context_common(&context);
 473         if (ret) {
 474                 DBG_ERR("kerberos init context failed (%s)\n",
 475                         error_message(ret));
 476                 goto out;
 477         }
 478
 479         ret = ads_keytab_open(context, &keytab);
 480         if (ret != 0) {
 481                 goto out;
 482         }
 483
 484         /* Construct our principal */
 485         if (strchr_m(srvPrinc, '@')) {
 486                 /* It's a fully-named principal. */
 487                 princ_s = talloc_asprintf(frame, "%s", srvPrinc);
 488                 if (!princ_s) {
 489                         ret = -1;
 490                         goto out;
 491                 }
 492         } else if (srvPrinc[strlen(srvPrinc)-1] == '$') {
 493                 /* It's the machine account, as used by smbclient clients. */
 494                 princ_s = talloc_asprintf(frame, "%s@%s",
 495                                           srvPrinc, lp_realm());
 496                 if (!princ_s) {
 497                         ret = -1;
 498                         goto out;
 499                 }
 500         } else {
 501                 /*
 502                  * It's a normal service principal.
 503                  */
 504                 char *my_fqdn = NULL;
 505                 char *tmp = NULL;
 506
 507                 /*
 508                  * SPN should have '/' otherwise we
 509                  * need to fallback and find our dnshostname
 510                  */
 511                 tmp = strchr_m(srvPrinc, '/');
 512                 if (tmp == NULL) {
 513                         my_fqdn = ads_get_dnshostname(ads, frame, lp_netbios_name());
 514                         if (!my_fqdn) {
 515                                 DBG_ERR("unable to determine machine account's dns name in "
 516                                         "AD!\n");
 517                                 ret = -1;
 518                                 goto out;
 519                         }
 520                 }
 521
 522                 ok = service_or_spn_to_kerberos_princ(frame,
 523                                                       srvPrinc,
 524                                                       my_fqdn,
 525                                                       &princ_s,
 526                                                       &short_princ_s);
 527                 if (!ok) {
 528                         ret = -1;
 529                         goto out;
 530                 }
 531         }
 532
 533         ret = smb_krb5_parse_name(context, princ_s, &princ);
 534         if (ret) {
 535                 DEBUG(1, (__location__ ": smb_krb5_parse_name(%s) "
 536                           "failed (%s)\n", princ_s, error_message(ret)));
 537                 goto out;
 538         }
 539
 540         if (short_princ_s != NULL) {
 541                 ret = smb_krb5_parse_name(context, short_princ_s, &short_princ);
 542                 if (ret) {
 543                         DEBUG(1, (__location__ ": smb_krb5_parse_name(%s) "
 544                                   "failed (%s)\n", short_princ_s, error_message(ret)));
 545                         goto out;
 546                 }
 547         }
 548
 549         /* Seek and delete old keytab entries */
 550         ret = smb_krb5_kt_seek_and_delete_old_entries(context,
 551                                                       keytab,
 552                                                       false, /* keep_old_kvno */
 553                                                       -1,
 554                                                       false, /* enctype_only */
 555                                                       ENCTYPE_NULL,
 556                                                       princ_s,
 557                                                       princ,
 558                                                       false); /* flush */
 559         if (ret) {
 560                 goto out;
 561         }
 562
 563         if (short_princ_s == NULL) {
 564                 goto out;
 565         }
 566
 567         /* Seek and delete old keytab entries */
 568         ret = smb_krb5_kt_seek_and_delete_old_entries(context,
 569                                                       keytab,
 570                                                       false, /* keep_old_kvno */
 571                                                       -1,
 572                                                       false, /* enctype_only */
 573                                                       ENCTYPE_NULL,
 574                                                       short_princ_s,
 575                                                       short_princ,
 576                                                       false); /* flush */
 577         if (ret) {
 578                 goto out;
 579         }
 580
 581 out:
 582         if (princ) {
 583                 krb5_free_principal(context, princ);
 584         }
 585         if (short_princ) {
 586                 krb5_free_principal(context, short_princ);
 587         }
 588         if (keytab) {
 589                 krb5_kt_close(context, keytab);
 590         }
 591         if (context) {
 592                 krb5_free_context(context);
 593         }
 594         TALLOC_FREE(frame);
 595         return ret;
 596 }
 597
 598 /**********************************************************************
 599  Flushes all entries from the system keytab.
 600 ***********************************************************************/
 601
 602 int ads_keytab_flush(ADS_STRUCT *ads)
 603 {
 604         krb5_error_code ret = 0;
 605         krb5_context context = NULL;
 606         krb5_keytab keytab = NULL;
 607         ADS_STATUS aderr;
 608
 609         ret = smb_krb5_init_context_common(&context);
 610         if (ret) {
 611                 DBG_ERR("kerberos init context failed (%s)\n",
 612                         error_message(ret));
 613                 return ret;
 614         }
 615
 616         ret = ads_keytab_open(context, &keytab);
 617         if (ret != 0) {
 618                 goto out;
 619         }
 620
 621         /* Seek and delete all old keytab entries */
 622         ret = smb_krb5_kt_seek_and_delete_old_entries(context,
 623                                                       keytab,
 624                                                       false, /* keep_old_kvno */
 625                                                       -1,
 626                                                       false, /* enctype_only */
 627                                                       ENCTYPE_NULL,
 628                                                       NULL,
 629                                                       NULL,
 630                                                       true); /* flush */
 631         if (ret) {
 632                 goto out;
 633         }
 634
 635         aderr = ads_clear_service_principal_names(ads, lp_netbios_name());
 636         if (!ADS_ERR_OK(aderr)) {
 637                 DEBUG(1, (__location__ ": Error while clearing service "
 638                           "principal listings in LDAP.\n"));
 639                 ret = -1;
 640                 goto out;
 641         }
 642
 643 out:
 644         if (keytab) {
 645                 krb5_kt_close(context, keytab);
 646         }
 647         if (context) {
 648                 krb5_free_context(context);
 649         }
 650         return ret;
 651 }
 652
 653 /**********************************************************************
 654  Adds all the required service principals to the system keytab.
 655 ***********************************************************************/
 656
 657 int ads_keytab_create_default(ADS_STRUCT *ads)
 658 {
 659         krb5_error_code ret = 0;
 660         krb5_context context = NULL;
 661         krb5_keytab keytab = NULL;
 662         krb5_kt_cursor cursor = {0};
 663         krb5_keytab_entry kt_entry = {0};
 664         krb5_kvno kvno;
 665         size_t found = 0;
 666         char *sam_account_name, *upn;
 667         char **oldEntries = NULL, *princ_s[26];
 668         TALLOC_CTX *frame;
 669         char *machine_name;
 670         char **spn_array;
 671         size_t num_spns;
 672         size_t i;
 673         bool ok = false;
 674         ADS_STATUS status;
 675
 676         ZERO_STRUCT(kt_entry);
 677         ZERO_STRUCT(cursor);
 678
 679         frame = talloc_stackframe();
 680         if (frame == NULL) {
 681                 ret = -1;
 682                 goto done;
 683         }
 684
 685         status = ads_get_service_principal_names(frame,
 686                                                  ads,
 687                                                  lp_netbios_name(),
 688                                                  &spn_array,
 689                                                  &num_spns);
 690         if (!ADS_ERR_OK(status)) {
 691                 ret = -1;
 692                 goto done;
 693         }
 694
 695         for (i = 0; i < num_spns; i++) {
 696                 char *srv_princ;
 697                 char *p;
 698
 699                 srv_princ = strlower_talloc(frame, spn_array[i]);
 700                 if (srv_princ == NULL) {
 701                         ret = -1;
 702                         goto done;
 703                 }
 704
 705                 p = strchr_m(srv_princ, '/');
 706                 if (p == NULL) {
 707                         continue;
 708                 }
 709                 p[0] = '\0';
 710
 711                 /* Add the SPNs found on the DC */
 712                 ret = ads_keytab_add_entry(ads, srv_princ, false);
 713                 if (ret != 0) {
 714                         DEBUG(1, ("ads_keytab_add_entry failed while "
 715                                   "adding '%s' principal.\n",
 716                                   spn_array[i]));
 717                         goto done;
 718                 }
 719         }
 720
 721 #if 0   /* don't create the CIFS/... keytab entries since no one except smbd
 722            really needs them and we will fall back to verifying against
 723            secrets.tdb */
 724
 725         ret = ads_keytab_add_entry(ads, "cifs", false));
 726         if (ret != 0 ) {
 727                 DEBUG(1, (__location__ ": ads_keytab_add_entry failed while "
 728                           "adding 'cifs'.\n"));
 729                 return ret;
 730         }
 731 #endif
 732
 733         memset(princ_s, '\0', sizeof(princ_s));
 734
 735         ret = smb_krb5_init_context_common(&context);
 736         if (ret) {
 737                 DBG_ERR("kerberos init context failed (%s)\n",
 738                         error_message(ret));
 739                 goto done;
 740         }
 741
 742         machine_name = talloc_strdup(frame, lp_netbios_name());
 743         if (!machine_name) {
 744                 ret = -1;
 745                 goto done;
 746         }
 747
 748         /* now add the userPrincipalName and sAMAccountName entries */
 749         ok = ads_has_samaccountname(ads, frame, machine_name);
 750         if (!ok) {
 751                 DEBUG(0, (__location__ ": unable to determine machine "
 752                           "account's name in AD!\n"));
 753                 ret = -1;
 754                 goto done;
 755         }
 756
 757         /*
 758          * append '$' to netbios name so 'ads_keytab_add_entry' recognises
 759          * it as a machine account rather than a service or Windows SPN.
 760          */
 761         sam_account_name = talloc_asprintf(frame, "%s$",machine_name);
 762         if (sam_account_name == NULL) {
 763                 ret = -1;
 764                 goto done;
 765         }
 766         /* upper case the sAMAccountName to make it easier for apps to
 767            know what case to use in the keytab file */
 768         if (!strupper_m(sam_account_name)) {
 769                 ret = -1;
 770                 goto done;
 771         }
 772
 773         ret = ads_keytab_add_entry(ads, sam_account_name, false);
 774         if (ret != 0) {
 775                 DEBUG(1, (__location__ ": ads_keytab_add_entry() failed "
 776                           "while adding sAMAccountName (%s)\n",
 777                           sam_account_name));
 778                 goto done;
 779         }
 780
 781         /* remember that not every machine account will have a upn */
 782         upn = ads_get_upn(ads, frame, machine_name);
 783         if (upn) {
 784                 ret = ads_keytab_add_entry(ads, upn, false);
 785                 if (ret != 0) {
 786                         DEBUG(1, (__location__ ": ads_keytab_add_entry() "
 787                                   "failed while adding UPN (%s)\n", upn));
 788                         goto done;
 789                 }
 790         }
 791
 792         /* Now loop through the keytab and update any other existing entries */
 793         kvno = (krb5_kvno)ads_get_machine_kvno(ads, machine_name);
 794         if (kvno == (krb5_kvno)-1) {
 795                 DEBUG(1, (__location__ ": ads_get_machine_kvno() failed to "
 796                           "determine the system's kvno.\n"));
 797                 goto done;
 798         }
 799
 800         DEBUG(3, (__location__ ": Searching for keytab entries to preserve "
 801                   "and update.\n"));
 802
 803         ret = ads_keytab_open(context, &keytab);
 804         if (ret != 0) {
 805                 goto done;
 806         }
 807
 808         ret = krb5_kt_start_seq_get(context, keytab, &cursor);
 809         if (ret != KRB5_KT_END && ret != ENOENT ) {
 810                 while ((ret = krb5_kt_next_entry(context, keytab,
 811                                                  &kt_entry, &cursor)) == 0) {
 812                         smb_krb5_kt_free_entry(context, &kt_entry);
 813                         ZERO_STRUCT(kt_entry);
 814                         found++;
 815                 }
 816         }
 817         krb5_kt_end_seq_get(context, keytab, &cursor);
 818         ZERO_STRUCT(cursor);
 819
 820         /*
 821          * Hmmm. There is no "rewind" function for the keytab. This means we
 822          * have a race condition where someone else could add entries after
 823          * we've counted them. Re-open asap to minimise the race. JRA.
 824          */
 825         DEBUG(3, (__location__ ": Found %zd entries in the keytab.\n", found));
 826         if (!found) {
 827                 goto done;
 828         }
 829
 830         oldEntries = talloc_zero_array(frame, char *, found + 1);
 831         if (!oldEntries) {
 832                 DEBUG(1, (__location__ ": Failed to allocate space to store "
 833                           "the old keytab entries (talloc failed?).\n"));
 834                 ret = -1;
 835                 goto done;
 836         }
 837
 838         ret = krb5_kt_start_seq_get(context, keytab, &cursor);
 839         if (ret == KRB5_KT_END || ret == ENOENT) {
 840                 krb5_kt_end_seq_get(context, keytab, &cursor);
 841                 ZERO_STRUCT(cursor);
 842                 goto done;
 843         }
 844
 845         while (krb5_kt_next_entry(context, keytab, &kt_entry, &cursor) == 0) {
 846                 if (kt_entry.vno != kvno) {
 847                         char *ktprinc = NULL;
 848                         char *p;
 849
 850                         /* This returns a malloc'ed string in ktprinc. */
 851                         ret = smb_krb5_unparse_name(oldEntries, context,
 852                                                     kt_entry.principal,
 853                                                     &ktprinc);
 854                         if (ret) {
 855                                 DEBUG(1, (__location__
 856                                          ": smb_krb5_unparse_name failed "
 857                                          "(%s)\n", error_message(ret)));
 858                                 goto done;
 859                         }
 860                         /*
 861                          * From looking at the krb5 source they don't seem to
 862                          * take locale or mb strings into account.
 863                          * Maybe this is because they assume utf8 ?
 864                          * In this case we may need to convert from utf8 to
 865                          * mb charset here ? JRA.
 866                          */
 867                         p = strchr_m(ktprinc, '@');
 868                         if (p) {
 869                                 *p = '\0';
 870                         }
 871
 872                         p = strchr_m(ktprinc, '/');
 873                         if (p) {
 874                                 *p = '\0';
 875                         }
 876                         for (i = 0; i < found; i++) {
 877                                 if (!oldEntries[i]) {
 878                                         oldEntries[i] = ktprinc;
 879                                         break;
 880                                 }
 881                                 if (!strcmp(oldEntries[i], ktprinc)) {
 882                                         TALLOC_FREE(ktprinc);
 883                                         break;
 884                                 }
 885                         }
 886                         if (i == found) {
 887                                 TALLOC_FREE(ktprinc);
 888                         }
 889                 }
 890                 smb_krb5_kt_free_entry(context, &kt_entry);
 891                 ZERO_STRUCT(kt_entry);
 892         }
 893         krb5_kt_end_seq_get(context, keytab, &cursor);
 894         ZERO_STRUCT(cursor);
 895
 896         ret = 0;
 897         for (i = 0; oldEntries[i]; i++) {
 898                 ret |= ads_keytab_add_entry(ads, oldEntries[i], false);
 899                 TALLOC_FREE(oldEntries[i]);
 900         }
 901
 902 done:
 903         TALLOC_FREE(oldEntries);
 904         TALLOC_FREE(frame);
 905
 906         if (context) {
 907                 if (!all_zero((uint8_t *)&kt_entry, sizeof(kt_entry))) {
 908                         smb_krb5_kt_free_entry(context, &kt_entry);
 909                 }
 910                 if (!all_zero((uint8_t *)&cursor, sizeof(cursor)) && keytab) {
 911                         krb5_kt_end_seq_get(context, keytab, &cursor);
 912                 }
 913                 if (keytab) {
 914                         krb5_kt_close(context, keytab);
 915                 }
 916                 krb5_free_context(context);
 917         }
 918         return ret;
 919 }
 920
 921 #endif /* HAVE_ADS */
 922
 923 /**********************************************************************
 924  List system keytab.
 925 ***********************************************************************/
 926
 927 int ads_keytab_list(const char *keytab_name)
 928 {
 929         krb5_error_code ret = 0;
 930         krb5_context context = NULL;
 931         krb5_keytab keytab = NULL;
 932         krb5_kt_cursor cursor;
 933         krb5_keytab_entry kt_entry;
 934
 935         ZERO_STRUCT(kt_entry);
 936         ZERO_STRUCT(cursor);
 937
 938         ret = smb_krb5_init_context_common(&context);
 939         if (ret) {
 940                 DBG_ERR("kerberos init context failed (%s)\n",
 941                         error_message(ret));
 942                 return ret;
 943         }
 944
 945         if (keytab_name == NULL) {
 946 #ifdef HAVE_ADS
 947                 ret = ads_keytab_open(context, &keytab);
 948 #else
 949                 ret = ENOENT;
 950 #endif
 951         } else {
 952                 ret = smb_krb5_kt_open(context, keytab_name, False, &keytab);
 953         }
 954         if (ret) {
 955                 DEBUG(1, ("smb_krb5_kt_open failed (%s)\n",
 956                           error_message(ret)));
 957                 goto out;
 958         }
 959
 960         ret = krb5_kt_start_seq_get(context, keytab, &cursor);
 961         if (ret) {
 962                 ZERO_STRUCT(cursor);
 963                 goto out;
 964         }
 965
 966         printf("Vno  Type                                        Principal\n");
 967
 968         while (krb5_kt_next_entry(context, keytab, &kt_entry, &cursor) == 0) {
 969
 970                 char *princ_s = NULL;
 971                 char *etype_s = NULL;
 972                 krb5_enctype enctype = 0;
 973
 974                 ret = smb_krb5_unparse_name(talloc_tos(), context,
 975                                             kt_entry.principal, &princ_s);
 976                 if (ret) {
 977                         goto out;
 978                 }
 979
 980                 enctype = smb_krb5_kt_get_enctype_from_entry(&kt_entry);
 981
 982                 ret = smb_krb5_enctype_to_string(context, enctype, &etype_s);
 983                 if (ret &&
 984                     (asprintf(&etype_s, "UNKNOWN: %d", enctype) == -1)) {
 985                         TALLOC_FREE(princ_s);
 986                         goto out;
 987                 }
 988
 989                 printf("%3d  %-43s %s\n", kt_entry.vno, etype_s, princ_s);
 990
 991                 TALLOC_FREE(princ_s);
 992                 SAFE_FREE(etype_s);
 993
 994                 ret = smb_krb5_kt_free_entry(context, &kt_entry);
 995                 if (ret) {
 996                         goto out;
 997                 }
 998         }
 999
1000         ret = krb5_kt_end_seq_get(context, keytab, &cursor);
1001         if (ret) {
1002                 goto out;
1003         }
1004
1005         /* Ensure we don't double free. */
1006         ZERO_STRUCT(kt_entry);
1007         ZERO_STRUCT(cursor);
1008 out:
1009
1010         if (!all_zero((uint8_t *)&kt_entry, sizeof(kt_entry))) {
1011                 smb_krb5_kt_free_entry(context, &kt_entry);
1012         }
1013         if (!all_zero((uint8_t *)&cursor, sizeof(cursor)) && keytab) {
1014                 krb5_kt_end_seq_get(context, keytab, &cursor);
1015         }
1016
1017         if (keytab) {
1018                 krb5_kt_close(context, keytab);
1019         }
1020         if (context) {
1021                 krb5_free_context(context);
1022         }
1023         return ret;
1024 }
1025
1026 #endif /* HAVE_KRB5 */