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 /**********************************************************************
  89  Adds a single service principal, i.e. 'host' to the system keytab
  90 ***********************************************************************/
  91
  92 int ads_keytab_add_entry(ADS_STRUCT *ads, const char *srvPrinc)
  93 {
  94         krb5_error_code ret = 0;
  95         krb5_context context = NULL;
  96         krb5_keytab keytab = NULL;
  97         krb5_data password;
  98         krb5_kvno kvno;
  99         krb5_enctype enctypes[6] = {
 100                 ENCTYPE_DES_CBC_CRC,
 101                 ENCTYPE_DES_CBC_MD5,
 102 #ifdef HAVE_ENCTYPE_AES128_CTS_HMAC_SHA1_96
 103                 ENCTYPE_AES128_CTS_HMAC_SHA1_96,
 104 #endif
 105 #ifdef HAVE_ENCTYPE_AES256_CTS_HMAC_SHA1_96
 106                 ENCTYPE_AES256_CTS_HMAC_SHA1_96,
 107 #endif
 108                 ENCTYPE_ARCFOUR_HMAC,
 109                 0
 110         };
 111         char *princ_s = NULL;
 112         char *short_princ_s = NULL;
 113         char *salt_princ_s = NULL;
 114         char *password_s = NULL;
 115         char *my_fqdn;
 116         TALLOC_CTX *tmpctx = NULL;
 117         char *machine_name;
 118         ADS_STATUS aderr;
 119         int i;
 120
 121         initialize_krb5_error_table();
 122         ret = krb5_init_context(&context);
 123         if (ret) {
 124                 DEBUG(1, (__location__ ": could not krb5_init_context: %s\n",
 125                           error_message(ret)));
 126                 return -1;
 127         }
 128
 129         ret = ads_keytab_open(context, &keytab);
 130         if (ret != 0) {
 131                 goto out;
 132         }
 133
 134         /* retrieve the password */
 135         if (!secrets_init()) {
 136                 DEBUG(1, (__location__ ": secrets_init failed\n"));
 137                 ret = -1;
 138                 goto out;
 139         }
 140         password_s = secrets_fetch_machine_password(lp_workgroup(), NULL, NULL);
 141         if (!password_s) {
 142                 DEBUG(1, (__location__ ": failed to fetch machine password\n"));
 143                 ret = -1;
 144                 goto out;
 145         }
 146         ZERO_STRUCT(password);
 147         password.data = password_s;
 148         password.length = strlen(password_s);
 149
 150         /* we need the dNSHostName value here */
 151         tmpctx = talloc_init(__location__);
 152         if (!tmpctx) {
 153                 DEBUG(0, (__location__ ": talloc_init() failed!\n"));
 154                 ret = -1;
 155                 goto out;
 156         }
 157
 158         my_fqdn = ads_get_dnshostname(ads, tmpctx, lp_netbios_name());
 159         if (!my_fqdn) {
 160                 DEBUG(0, (__location__ ": unable to determine machine "
 161                           "account's dns name in AD!\n"));
 162                 ret = -1;
 163                 goto out;
 164         }
 165
 166         machine_name = ads_get_samaccountname(ads, tmpctx, lp_netbios_name());
 167         if (!machine_name) {
 168                 DEBUG(0, (__location__ ": unable to determine machine "
 169                           "account's short name in AD!\n"));
 170                 ret = -1;
 171                 goto out;
 172         }
 173         /*strip the trailing '$' */
 174         machine_name[strlen(machine_name)-1] = '\0';
 175
 176         /* Construct our principal */
 177         if (strchr_m(srvPrinc, '@')) {
 178                 /* It's a fully-named principal. */
 179                 princ_s = talloc_asprintf(tmpctx, "%s", srvPrinc);
 180                 if (!princ_s) {
 181                         ret = -1;
 182                         goto out;
 183                 }
 184         } else if (srvPrinc[strlen(srvPrinc)-1] == '$') {
 185                 /* It's the machine account, as used by smbclient clients. */
 186                 princ_s = talloc_asprintf(tmpctx, "%s@%s",
 187                                           srvPrinc, lp_realm());
 188                 if (!princ_s) {
 189                         ret = -1;
 190                         goto out;
 191                 }
 192         } else {
 193                 /* It's a normal service principal.  Add the SPN now so that we
 194                  * can obtain credentials for it and double-check the salt value
 195                  * used to generate the service's keys. */
 196
 197                 princ_s = talloc_asprintf(tmpctx, "%s/%s@%s",
 198                                           srvPrinc, my_fqdn, lp_realm());
 199                 if (!princ_s) {
 200                         ret = -1;
 201                         goto out;
 202                 }
 203                 short_princ_s = talloc_asprintf(tmpctx, "%s/%s@%s",
 204                                                 srvPrinc, machine_name,
 205                                                 lp_realm());
 206                 if (short_princ_s == NULL) {
 207                         ret = -1;
 208                         goto out;
 209                 }
 210
 211                 /* According to http://support.microsoft.com/kb/326985/en-us,
 212                    certain principal names are automatically mapped to the
 213                    host/... principal in the AD account.
 214                    So only create these in the keytab, not in AD.  --jerry */
 215
 216                 if (!strequal(srvPrinc, "cifs") &&
 217                     !strequal(srvPrinc, "host")) {
 218                         DEBUG(3, (__location__ ": Attempting to add/update "
 219                                   "'%s'\n", princ_s));
 220
 221                         aderr = ads_add_service_principal_name(ads,
 222                                         lp_netbios_name(), my_fqdn, srvPrinc);
 223                         if (!ADS_ERR_OK(aderr)) {
 224                                 DEBUG(1, (__location__ ": failed to "
 225                                          "ads_add_service_principal_name.\n"));
 226                                 goto out;
 227                         }
 228                 }
 229         }
 230
 231         kvno = (krb5_kvno)ads_get_machine_kvno(ads, lp_netbios_name());
 232         if (kvno == -1) {
 233                 /* -1 indicates failure, everything else is OK */
 234                 DEBUG(1, (__location__ ": ads_get_machine_kvno failed to "
 235                          "determine the system's kvno.\n"));
 236                 ret = -1;
 237                 goto out;
 238         }
 239
 240         salt_princ_s = kerberos_secrets_fetch_salt_princ();
 241         if (salt_princ_s == NULL) {
 242                 DBG_WARNING("kerberos_secrets_fetch_salt_princ() failed\n");
 243                 ret = -1;
 244                 goto out;
 245         }
 246
 247         for (i = 0; enctypes[i]; i++) {
 248
 249                 /* add the fqdn principal to the keytab */
 250                 ret = smb_krb5_kt_add_entry(context,
 251                                             keytab,
 252                                             kvno,
 253                                             princ_s,
 254                                             salt_princ_s,
 255                                             enctypes[i],
 256                                             &password,
 257                                             false,
 258                                             false);
 259                 if (ret) {
 260                         DEBUG(1, (__location__ ": Failed to add entry to keytab\n"));
 261                         goto out;
 262                 }
 263
 264                 /* add the short principal name if we have one */
 265                 if (short_princ_s) {
 266                         ret = smb_krb5_kt_add_entry(context,
 267                                                     keytab,
 268                                                     kvno,
 269                                                     short_princ_s,
 270                                                     salt_princ_s,
 271                                                     enctypes[i],
 272                                                     &password,
 273                                                     false,
 274                                                     false);
 275                         if (ret) {
 276                                 DEBUG(1, (__location__
 277                                           ": Failed to add short entry to keytab\n"));
 278                                 goto out;
 279                         }
 280                 }
 281         }
 282
 283 out:
 284         SAFE_FREE(salt_princ_s);
 285         TALLOC_FREE(tmpctx);
 286
 287         if (keytab) {
 288                 krb5_kt_close(context, keytab);
 289         }
 290         if (context) {
 291                 krb5_free_context(context);
 292         }
 293         return (int)ret;
 294 }
 295
 296 /**********************************************************************
 297  Flushes all entries from the system keytab.
 298 ***********************************************************************/
 299
 300 int ads_keytab_flush(ADS_STRUCT *ads)
 301 {
 302         krb5_error_code ret = 0;
 303         krb5_context context = NULL;
 304         krb5_keytab keytab = NULL;
 305         krb5_kvno kvno;
 306         ADS_STATUS aderr;
 307
 308         initialize_krb5_error_table();
 309         ret = krb5_init_context(&context);
 310         if (ret) {
 311                 DEBUG(1, (__location__ ": could not krb5_init_context: %s\n",
 312                           error_message(ret)));
 313                 return ret;
 314         }
 315
 316         ret = ads_keytab_open(context, &keytab);
 317         if (ret != 0) {
 318                 goto out;
 319         }
 320
 321         kvno = (krb5_kvno)ads_get_machine_kvno(ads, lp_netbios_name());
 322         if (kvno == -1) {
 323                 /* -1 indicates a failure */
 324                 DEBUG(1, (__location__ ": Error determining the kvno.\n"));
 325                 goto out;
 326         }
 327
 328         /* Seek and delete old keytab entries */
 329         ret = smb_krb5_kt_seek_and_delete_old_entries(context,
 330                                                       keytab,
 331                                                       kvno,
 332                                                       ENCTYPE_NULL,
 333                                                       NULL,
 334                                                       NULL,
 335                                                       true,
 336                                                       false);
 337         if (ret) {
 338                 goto out;
 339         }
 340
 341         aderr = ads_clear_service_principal_names(ads, lp_netbios_name());
 342         if (!ADS_ERR_OK(aderr)) {
 343                 DEBUG(1, (__location__ ": Error while clearing service "
 344                           "principal listings in LDAP.\n"));
 345                 goto out;
 346         }
 347
 348 out:
 349         if (keytab) {
 350                 krb5_kt_close(context, keytab);
 351         }
 352         if (context) {
 353                 krb5_free_context(context);
 354         }
 355         return ret;
 356 }
 357
 358 /**********************************************************************
 359  Adds all the required service principals to the system keytab.
 360 ***********************************************************************/
 361
 362 int ads_keytab_create_default(ADS_STRUCT *ads)
 363 {
 364         krb5_error_code ret = 0;
 365         krb5_context context = NULL;
 366         krb5_keytab keytab = NULL;
 367         krb5_kt_cursor cursor = {0};
 368         krb5_keytab_entry kt_entry = {0};
 369         krb5_kvno kvno;
 370         size_t found = 0;
 371         char *sam_account_name, *upn;
 372         char **oldEntries = NULL, *princ_s[26];
 373         TALLOC_CTX *frame;
 374         char *machine_name;
 375         char **spn_array;
 376         size_t num_spns;
 377         size_t i;
 378         ADS_STATUS status;
 379
 380         ZERO_STRUCT(kt_entry);
 381         ZERO_STRUCT(cursor);
 382
 383         frame = talloc_stackframe();
 384         if (frame == NULL) {
 385                 ret = -1;
 386                 goto done;
 387         }
 388
 389         status = ads_get_service_principal_names(frame,
 390                                                  ads,
 391                                                  lp_netbios_name(),
 392                                                  &spn_array,
 393                                                  &num_spns);
 394         if (!ADS_ERR_OK(status)) {
 395                 ret = -1;
 396                 goto done;
 397         }
 398
 399         for (i = 0; i < num_spns; i++) {
 400                 char *srv_princ;
 401                 char *p;
 402
 403                 srv_princ = strlower_talloc(frame, spn_array[i]);
 404                 if (srv_princ == NULL) {
 405                         ret = -1;
 406                         goto done;
 407                 }
 408
 409                 p = strchr_m(srv_princ, '/');
 410                 if (p == NULL) {
 411                         continue;
 412                 }
 413                 p[0] = '\0';
 414
 415                 /* Add the SPNs found on the DC */
 416                 ret = ads_keytab_add_entry(ads, srv_princ);
 417                 if (ret != 0) {
 418                         DEBUG(1, ("ads_keytab_add_entry failed while "
 419                                   "adding '%s' principal.\n",
 420                                   spn_array[i]));
 421                         goto done;
 422                 }
 423         }
 424
 425 #if 0   /* don't create the CIFS/... keytab entries since no one except smbd
 426            really needs them and we will fall back to verifying against
 427            secrets.tdb */
 428
 429         ret = ads_keytab_add_entry(ads, "cifs"));
 430         if (ret != 0 ) {
 431                 DEBUG(1, (__location__ ": ads_keytab_add_entry failed while "
 432                           "adding 'cifs'.\n"));
 433                 return ret;
 434         }
 435 #endif
 436
 437         memset(princ_s, '\0', sizeof(princ_s));
 438
 439         initialize_krb5_error_table();
 440         ret = krb5_init_context(&context);
 441         if (ret) {
 442                 DEBUG(1, (__location__ ": could not krb5_init_context: %s\n",
 443                           error_message(ret)));
 444                 goto done;
 445         }
 446
 447         machine_name = talloc_strdup(frame, lp_netbios_name());
 448         if (!machine_name) {
 449                 ret = -1;
 450                 goto done;
 451         }
 452
 453         /* now add the userPrincipalName and sAMAccountName entries */
 454         sam_account_name = ads_get_samaccountname(ads, frame, machine_name);
 455         if (!sam_account_name) {
 456                 DEBUG(0, (__location__ ": unable to determine machine "
 457                           "account's name in AD!\n"));
 458                 ret = -1;
 459                 goto done;
 460         }
 461
 462         /* upper case the sAMAccountName to make it easier for apps to
 463            know what case to use in the keytab file */
 464         if (!strupper_m(sam_account_name)) {
 465                 ret = -1;
 466                 goto done;
 467         }
 468
 469         ret = ads_keytab_add_entry(ads, sam_account_name);
 470         if (ret != 0) {
 471                 DEBUG(1, (__location__ ": ads_keytab_add_entry() failed "
 472                           "while adding sAMAccountName (%s)\n",
 473                           sam_account_name));
 474                 goto done;
 475         }
 476
 477         /* remember that not every machine account will have a upn */
 478         upn = ads_get_upn(ads, frame, machine_name);
 479         if (upn) {
 480                 ret = ads_keytab_add_entry(ads, upn);
 481                 if (ret != 0) {
 482                         DEBUG(1, (__location__ ": ads_keytab_add_entry() "
 483                                   "failed while adding UPN (%s)\n", upn));
 484                         goto done;
 485                 }
 486         }
 487
 488         /* Now loop through the keytab and update any other existing entries */
 489         kvno = (krb5_kvno)ads_get_machine_kvno(ads, machine_name);
 490         if (kvno == (krb5_kvno)-1) {
 491                 DEBUG(1, (__location__ ": ads_get_machine_kvno() failed to "
 492                           "determine the system's kvno.\n"));
 493                 goto done;
 494         }
 495
 496         DEBUG(3, (__location__ ": Searching for keytab entries to preserve "
 497                   "and update.\n"));
 498
 499         ret = ads_keytab_open(context, &keytab);
 500         if (ret != 0) {
 501                 goto done;
 502         }
 503
 504         ret = krb5_kt_start_seq_get(context, keytab, &cursor);
 505         if (ret != KRB5_KT_END && ret != ENOENT ) {
 506                 while ((ret = krb5_kt_next_entry(context, keytab,
 507                                                  &kt_entry, &cursor)) == 0) {
 508                         smb_krb5_kt_free_entry(context, &kt_entry);
 509                         ZERO_STRUCT(kt_entry);
 510                         found++;
 511                 }
 512         }
 513         krb5_kt_end_seq_get(context, keytab, &cursor);
 514         ZERO_STRUCT(cursor);
 515
 516         /*
 517          * Hmmm. There is no "rewind" function for the keytab. This means we
 518          * have a race condition where someone else could add entries after
 519          * we've counted them. Re-open asap to minimise the race. JRA.
 520          */
 521         DEBUG(3, (__location__ ": Found %zd entries in the keytab.\n", found));
 522         if (!found) {
 523                 goto done;
 524         }
 525
 526         oldEntries = talloc_zero_array(frame, char *, found + 1);
 527         if (!oldEntries) {
 528                 DEBUG(1, (__location__ ": Failed to allocate space to store "
 529                           "the old keytab entries (talloc failed?).\n"));
 530                 ret = -1;
 531                 goto done;
 532         }
 533
 534         ret = krb5_kt_start_seq_get(context, keytab, &cursor);
 535         if (ret == KRB5_KT_END || ret == ENOENT) {
 536                 krb5_kt_end_seq_get(context, keytab, &cursor);
 537                 ZERO_STRUCT(cursor);
 538                 goto done;
 539         }
 540
 541         while (krb5_kt_next_entry(context, keytab, &kt_entry, &cursor) == 0) {
 542                 if (kt_entry.vno != kvno) {
 543                         char *ktprinc = NULL;
 544                         char *p;
 545
 546                         /* This returns a malloc'ed string in ktprinc. */
 547                         ret = smb_krb5_unparse_name(oldEntries, context,
 548                                                     kt_entry.principal,
 549                                                     &ktprinc);
 550                         if (ret) {
 551                                 DEBUG(1, (__location__
 552                                          ": smb_krb5_unparse_name failed "
 553                                          "(%s)\n", error_message(ret)));
 554                                 goto done;
 555                         }
 556                         /*
 557                          * From looking at the krb5 source they don't seem to
 558                          * take locale or mb strings into account.
 559                          * Maybe this is because they assume utf8 ?
 560                          * In this case we may need to convert from utf8 to
 561                          * mb charset here ? JRA.
 562                          */
 563                         p = strchr_m(ktprinc, '@');
 564                         if (p) {
 565                                 *p = '\0';
 566                         }
 567
 568                         p = strchr_m(ktprinc, '/');
 569                         if (p) {
 570                                 *p = '\0';
 571                         }
 572                         for (i = 0; i < found; i++) {
 573                                 if (!oldEntries[i]) {
 574                                         oldEntries[i] = ktprinc;
 575                                         break;
 576                                 }
 577                                 if (!strcmp(oldEntries[i], ktprinc)) {
 578                                         TALLOC_FREE(ktprinc);
 579                                         break;
 580                                 }
 581                         }
 582                         if (i == found) {
 583                                 TALLOC_FREE(ktprinc);
 584                         }
 585                 }
 586                 smb_krb5_kt_free_entry(context, &kt_entry);
 587                 ZERO_STRUCT(kt_entry);
 588         }
 589         krb5_kt_end_seq_get(context, keytab, &cursor);
 590         ZERO_STRUCT(cursor);
 591
 592         ret = 0;
 593         for (i = 0; oldEntries[i]; i++) {
 594                 ret |= ads_keytab_add_entry(ads, oldEntries[i]);
 595                 TALLOC_FREE(oldEntries[i]);
 596         }
 597
 598 done:
 599         TALLOC_FREE(oldEntries);
 600         TALLOC_FREE(frame);
 601
 602         if (context) {
 603                 if (!all_zero((uint8_t *)&kt_entry, sizeof(kt_entry))) {
 604                         smb_krb5_kt_free_entry(context, &kt_entry);
 605                 }
 606                 if (!all_zero((uint8_t *)&cursor, sizeof(cursor)) && keytab) {
 607                         krb5_kt_end_seq_get(context, keytab, &cursor);
 608                 }
 609                 if (keytab) {
 610                         krb5_kt_close(context, keytab);
 611                 }
 612                 krb5_free_context(context);
 613         }
 614         return ret;
 615 }
 616
 617 #endif /* HAVE_ADS */
 618
 619 /**********************************************************************
 620  List system keytab.
 621 ***********************************************************************/
 622
 623 int ads_keytab_list(const char *keytab_name)
 624 {
 625         krb5_error_code ret = 0;
 626         krb5_context context = NULL;
 627         krb5_keytab keytab = NULL;
 628         krb5_kt_cursor cursor;
 629         krb5_keytab_entry kt_entry;
 630
 631         ZERO_STRUCT(kt_entry);
 632         ZERO_STRUCT(cursor);
 633
 634         initialize_krb5_error_table();
 635         ret = krb5_init_context(&context);
 636         if (ret) {
 637                 DEBUG(1, (__location__ ": could not krb5_init_context: %s\n",
 638                           error_message(ret)));
 639                 return ret;
 640         }
 641
 642         if (keytab_name == NULL) {
 643                 ret = ads_keytab_open(context, &keytab);
 644         } else {
 645                 ret = smb_krb5_kt_open(context, keytab_name, False, &keytab);
 646         }
 647         if (ret) {
 648                 DEBUG(1, ("smb_krb5_kt_open failed (%s)\n",
 649                           error_message(ret)));
 650                 goto out;
 651         }
 652
 653         ret = krb5_kt_start_seq_get(context, keytab, &cursor);
 654         if (ret) {
 655                 ZERO_STRUCT(cursor);
 656                 goto out;
 657         }
 658
 659         printf("Vno  Type                                        Principal\n");
 660
 661         while (krb5_kt_next_entry(context, keytab, &kt_entry, &cursor) == 0) {
 662
 663                 char *princ_s = NULL;
 664                 char *etype_s = NULL;
 665                 krb5_enctype enctype = 0;
 666
 667                 ret = smb_krb5_unparse_name(talloc_tos(), context,
 668                                             kt_entry.principal, &princ_s);
 669                 if (ret) {
 670                         goto out;
 671                 }
 672
 673                 enctype = smb_krb5_kt_get_enctype_from_entry(&kt_entry);
 674
 675                 ret = smb_krb5_enctype_to_string(context, enctype, &etype_s);
 676                 if (ret &&
 677                     (asprintf(&etype_s, "UNKNOWN: %d\n", enctype) == -1)) {
 678                         TALLOC_FREE(princ_s);
 679                         goto out;
 680                 }
 681
 682                 printf("%3d  %-43s %s\n", kt_entry.vno, etype_s, princ_s);
 683
 684                 TALLOC_FREE(princ_s);
 685                 SAFE_FREE(etype_s);
 686
 687                 ret = smb_krb5_kt_free_entry(context, &kt_entry);
 688                 if (ret) {
 689                         goto out;
 690                 }
 691         }
 692
 693         ret = krb5_kt_end_seq_get(context, keytab, &cursor);
 694         if (ret) {
 695                 goto out;
 696         }
 697
 698         /* Ensure we don't double free. */
 699         ZERO_STRUCT(kt_entry);
 700         ZERO_STRUCT(cursor);
 701 out:
 702
 703         if (!all_zero((uint8_t *)&kt_entry, sizeof(kt_entry))) {
 704                 smb_krb5_kt_free_entry(context, &kt_entry);
 705         }
 706         if (!all_zero((uint8_t *)&cursor, sizeof(cursor)) && keytab) {
 707                 krb5_kt_end_seq_get(context, keytab, &cursor);
 708         }
 709
 710         if (keytab) {
 711                 krb5_kt_close(context, keytab);
 712         }
 713         if (context) {
 714                 krb5_free_context(context);
 715         }
 716         return ret;
 717 }
 718
 719 #endif /* HAVE_KRB5 */