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         for (i = 0; enctypes[i]; i++) {
 241                 salt_princ_s = kerberos_fetch_salt_princ_for_host_princ(context,
 242                                                                         princ_s,
 243                                                                         enctypes[i]);
 244
 245                 /* add the fqdn principal to the keytab */
 246                 ret = smb_krb5_kt_add_entry(context,
 247                                             keytab,
 248                                             kvno,
 249                                             princ_s,
 250                                             salt_princ_s,
 251                                             enctypes[i],
 252                                             &password,
 253                                             false,
 254                                             false);
 255                 if (ret) {
 256                         DEBUG(1, (__location__ ": Failed to add entry to keytab\n"));
 257                         SAFE_FREE(salt_princ_s);
 258                         goto out;
 259                 }
 260
 261                 /* add the short principal name if we have one */
 262                 if (short_princ_s) {
 263                         ret = smb_krb5_kt_add_entry(context,
 264                                                     keytab,
 265                                                     kvno,
 266                                                     short_princ_s,
 267                                                     salt_princ_s,
 268                                                     enctypes[i],
 269                                                     &password,
 270                                                     false,
 271                                                     false);
 272                         if (ret) {
 273                                 DEBUG(1, (__location__
 274                                           ": Failed to add short entry to keytab\n"));
 275                                 SAFE_FREE(salt_princ_s);
 276                                 goto out;
 277                         }
 278                 }
 279                 SAFE_FREE(salt_princ_s);
 280         }
 281
 282 out:
 283         TALLOC_FREE(tmpctx);
 284
 285         if (keytab) {
 286                 krb5_kt_close(context, keytab);
 287         }
 288         if (context) {
 289                 krb5_free_context(context);
 290         }
 291         return (int)ret;
 292 }
 293
 294 /**********************************************************************
 295  Flushes all entries from the system keytab.
 296 ***********************************************************************/
 297
 298 int ads_keytab_flush(ADS_STRUCT *ads)
 299 {
 300         krb5_error_code ret = 0;
 301         krb5_context context = NULL;
 302         krb5_keytab keytab = NULL;
 303         krb5_kvno kvno;
 304         ADS_STATUS aderr;
 305
 306         initialize_krb5_error_table();
 307         ret = krb5_init_context(&context);
 308         if (ret) {
 309                 DEBUG(1, (__location__ ": could not krb5_init_context: %s\n",
 310                           error_message(ret)));
 311                 return ret;
 312         }
 313
 314         ret = ads_keytab_open(context, &keytab);
 315         if (ret != 0) {
 316                 goto out;
 317         }
 318
 319         kvno = (krb5_kvno)ads_get_machine_kvno(ads, lp_netbios_name());
 320         if (kvno == -1) {
 321                 /* -1 indicates a failure */
 322                 DEBUG(1, (__location__ ": Error determining the kvno.\n"));
 323                 goto out;
 324         }
 325
 326         /* Seek and delete old keytab entries */
 327         ret = smb_krb5_kt_seek_and_delete_old_entries(context,
 328                                                       keytab,
 329                                                       kvno,
 330                                                       ENCTYPE_NULL,
 331                                                       NULL,
 332                                                       NULL,
 333                                                       true,
 334                                                       false);
 335         if (ret) {
 336                 goto out;
 337         }
 338
 339         aderr = ads_clear_service_principal_names(ads, lp_netbios_name());
 340         if (!ADS_ERR_OK(aderr)) {
 341                 DEBUG(1, (__location__ ": Error while clearing service "
 342                           "principal listings in LDAP.\n"));
 343                 goto out;
 344         }
 345
 346 out:
 347         if (keytab) {
 348                 krb5_kt_close(context, keytab);
 349         }
 350         if (context) {
 351                 krb5_free_context(context);
 352         }
 353         return ret;
 354 }
 355
 356 /**********************************************************************
 357  Adds all the required service principals to the system keytab.
 358 ***********************************************************************/
 359
 360 int ads_keytab_create_default(ADS_STRUCT *ads)
 361 {
 362         krb5_error_code ret = 0;
 363         krb5_context context = NULL;
 364         krb5_keytab keytab = NULL;
 365         krb5_kt_cursor cursor = {0};
 366         krb5_keytab_entry kt_entry = {0};
 367         krb5_kvno kvno;
 368         size_t found = 0;
 369         char *sam_account_name, *upn;
 370         char **oldEntries = NULL, *princ_s[26];
 371         TALLOC_CTX *frame;
 372         char *machine_name;
 373         char **spn_array;
 374         size_t num_spns;
 375         size_t i;
 376         ADS_STATUS status;
 377
 378         ZERO_STRUCT(kt_entry);
 379         ZERO_STRUCT(cursor);
 380
 381         frame = talloc_stackframe();
 382         if (frame == NULL) {
 383                 ret = -1;
 384                 goto done;
 385         }
 386
 387         status = ads_get_service_principal_names(frame,
 388                                                  ads,
 389                                                  lp_netbios_name(),
 390                                                  &spn_array,
 391                                                  &num_spns);
 392         if (!ADS_ERR_OK(status)) {
 393                 ret = -1;
 394                 goto done;
 395         }
 396
 397         for (i = 0; i < num_spns; i++) {
 398                 char *srv_princ;
 399                 char *p;
 400
 401                 srv_princ = strlower_talloc(frame, spn_array[i]);
 402                 if (srv_princ == NULL) {
 403                         ret = -1;
 404                         goto done;
 405                 }
 406
 407                 p = strchr_m(srv_princ, '/');
 408                 if (p == NULL) {
 409                         continue;
 410                 }
 411                 p[0] = '\0';
 412
 413                 /* Add the SPNs found on the DC */
 414                 ret = ads_keytab_add_entry(ads, srv_princ);
 415                 if (ret != 0) {
 416                         DEBUG(1, ("ads_keytab_add_entry failed while "
 417                                   "adding '%s' principal.\n",
 418                                   spn_array[i]));
 419                         goto done;
 420                 }
 421         }
 422
 423 #if 0   /* don't create the CIFS/... keytab entries since no one except smbd
 424            really needs them and we will fall back to verifying against
 425            secrets.tdb */
 426
 427         ret = ads_keytab_add_entry(ads, "cifs"));
 428         if (ret != 0 ) {
 429                 DEBUG(1, (__location__ ": ads_keytab_add_entry failed while "
 430                           "adding 'cifs'.\n"));
 431                 return ret;
 432         }
 433 #endif
 434
 435         memset(princ_s, '\0', sizeof(princ_s));
 436
 437         initialize_krb5_error_table();
 438         ret = krb5_init_context(&context);
 439         if (ret) {
 440                 DEBUG(1, (__location__ ": could not krb5_init_context: %s\n",
 441                           error_message(ret)));
 442                 goto done;
 443         }
 444
 445         machine_name = talloc_strdup(frame, lp_netbios_name());
 446         if (!machine_name) {
 447                 ret = -1;
 448                 goto done;
 449         }
 450
 451         /* now add the userPrincipalName and sAMAccountName entries */
 452         sam_account_name = ads_get_samaccountname(ads, frame, machine_name);
 453         if (!sam_account_name) {
 454                 DEBUG(0, (__location__ ": unable to determine machine "
 455                           "account's name in AD!\n"));
 456                 ret = -1;
 457                 goto done;
 458         }
 459
 460         /* upper case the sAMAccountName to make it easier for apps to
 461            know what case to use in the keytab file */
 462         if (!strupper_m(sam_account_name)) {
 463                 ret = -1;
 464                 goto done;
 465         }
 466
 467         ret = ads_keytab_add_entry(ads, sam_account_name);
 468         if (ret != 0) {
 469                 DEBUG(1, (__location__ ": ads_keytab_add_entry() failed "
 470                           "while adding sAMAccountName (%s)\n",
 471                           sam_account_name));
 472                 goto done;
 473         }
 474
 475         /* remember that not every machine account will have a upn */
 476         upn = ads_get_upn(ads, frame, machine_name);
 477         if (upn) {
 478                 ret = ads_keytab_add_entry(ads, upn);
 479                 if (ret != 0) {
 480                         DEBUG(1, (__location__ ": ads_keytab_add_entry() "
 481                                   "failed while adding UPN (%s)\n", upn));
 482                         goto done;
 483                 }
 484         }
 485
 486         /* Now loop through the keytab and update any other existing entries */
 487         kvno = (krb5_kvno)ads_get_machine_kvno(ads, machine_name);
 488         if (kvno == (krb5_kvno)-1) {
 489                 DEBUG(1, (__location__ ": ads_get_machine_kvno() failed to "
 490                           "determine the system's kvno.\n"));
 491                 goto done;
 492         }
 493
 494         DEBUG(3, (__location__ ": Searching for keytab entries to preserve "
 495                   "and update.\n"));
 496
 497         ret = ads_keytab_open(context, &keytab);
 498         if (ret != 0) {
 499                 goto done;
 500         }
 501
 502         ret = krb5_kt_start_seq_get(context, keytab, &cursor);
 503         if (ret != KRB5_KT_END && ret != ENOENT ) {
 504                 while ((ret = krb5_kt_next_entry(context, keytab,
 505                                                  &kt_entry, &cursor)) == 0) {
 506                         smb_krb5_kt_free_entry(context, &kt_entry);
 507                         ZERO_STRUCT(kt_entry);
 508                         found++;
 509                 }
 510         }
 511         krb5_kt_end_seq_get(context, keytab, &cursor);
 512         ZERO_STRUCT(cursor);
 513
 514         /*
 515          * Hmmm. There is no "rewind" function for the keytab. This means we
 516          * have a race condition where someone else could add entries after
 517          * we've counted them. Re-open asap to minimise the race. JRA.
 518          */
 519         DEBUG(3, (__location__ ": Found %zd entries in the keytab.\n", found));
 520         if (!found) {
 521                 goto done;
 522         }
 523
 524         oldEntries = talloc_zero_array(frame, char *, found + 1);
 525         if (!oldEntries) {
 526                 DEBUG(1, (__location__ ": Failed to allocate space to store "
 527                           "the old keytab entries (talloc failed?).\n"));
 528                 ret = -1;
 529                 goto done;
 530         }
 531
 532         ret = krb5_kt_start_seq_get(context, keytab, &cursor);
 533         if (ret == KRB5_KT_END || ret == ENOENT) {
 534                 krb5_kt_end_seq_get(context, keytab, &cursor);
 535                 ZERO_STRUCT(cursor);
 536                 goto done;
 537         }
 538
 539         while (krb5_kt_next_entry(context, keytab, &kt_entry, &cursor) == 0) {
 540                 if (kt_entry.vno != kvno) {
 541                         char *ktprinc = NULL;
 542                         char *p;
 543
 544                         /* This returns a malloc'ed string in ktprinc. */
 545                         ret = smb_krb5_unparse_name(oldEntries, context,
 546                                                     kt_entry.principal,
 547                                                     &ktprinc);
 548                         if (ret) {
 549                                 DEBUG(1, (__location__
 550                                          ": smb_krb5_unparse_name failed "
 551                                          "(%s)\n", error_message(ret)));
 552                                 goto done;
 553                         }
 554                         /*
 555                          * From looking at the krb5 source they don't seem to
 556                          * take locale or mb strings into account.
 557                          * Maybe this is because they assume utf8 ?
 558                          * In this case we may need to convert from utf8 to
 559                          * mb charset here ? JRA.
 560                          */
 561                         p = strchr_m(ktprinc, '@');
 562                         if (p) {
 563                                 *p = '\0';
 564                         }
 565
 566                         p = strchr_m(ktprinc, '/');
 567                         if (p) {
 568                                 *p = '\0';
 569                         }
 570                         for (i = 0; i < found; i++) {
 571                                 if (!oldEntries[i]) {
 572                                         oldEntries[i] = ktprinc;
 573                                         break;
 574                                 }
 575                                 if (!strcmp(oldEntries[i], ktprinc)) {
 576                                         TALLOC_FREE(ktprinc);
 577                                         break;
 578                                 }
 579                         }
 580                         if (i == found) {
 581                                 TALLOC_FREE(ktprinc);
 582                         }
 583                 }
 584                 smb_krb5_kt_free_entry(context, &kt_entry);
 585                 ZERO_STRUCT(kt_entry);
 586         }
 587         krb5_kt_end_seq_get(context, keytab, &cursor);
 588         ZERO_STRUCT(cursor);
 589
 590         ret = 0;
 591         for (i = 0; oldEntries[i]; i++) {
 592                 ret |= ads_keytab_add_entry(ads, oldEntries[i]);
 593                 TALLOC_FREE(oldEntries[i]);
 594         }
 595
 596 done:
 597         TALLOC_FREE(oldEntries);
 598         TALLOC_FREE(frame);
 599
 600         if (context) {
 601                 if (!all_zero((uint8_t *)&kt_entry, sizeof(kt_entry))) {
 602                         smb_krb5_kt_free_entry(context, &kt_entry);
 603                 }
 604                 if (!all_zero((uint8_t *)&cursor, sizeof(cursor)) && keytab) {
 605                         krb5_kt_end_seq_get(context, keytab, &cursor);
 606                 }
 607                 if (keytab) {
 608                         krb5_kt_close(context, keytab);
 609                 }
 610                 krb5_free_context(context);
 611         }
 612         return ret;
 613 }
 614
 615 #endif /* HAVE_ADS */
 616
 617 /**********************************************************************
 618  List system keytab.
 619 ***********************************************************************/
 620
 621 int ads_keytab_list(const char *keytab_name)
 622 {
 623         krb5_error_code ret = 0;
 624         krb5_context context = NULL;
 625         krb5_keytab keytab = NULL;
 626         krb5_kt_cursor cursor;
 627         krb5_keytab_entry kt_entry;
 628
 629         ZERO_STRUCT(kt_entry);
 630         ZERO_STRUCT(cursor);
 631
 632         initialize_krb5_error_table();
 633         ret = krb5_init_context(&context);
 634         if (ret) {
 635                 DEBUG(1, (__location__ ": could not krb5_init_context: %s\n",
 636                           error_message(ret)));
 637                 return ret;
 638         }
 639
 640         ret = smb_krb5_kt_open(context, keytab_name, False, &keytab);
 641         if (ret) {
 642                 DEBUG(1, ("smb_krb5_kt_open failed (%s)\n",
 643                           error_message(ret)));
 644                 goto out;
 645         }
 646
 647         ret = krb5_kt_start_seq_get(context, keytab, &cursor);
 648         if (ret) {
 649                 ZERO_STRUCT(cursor);
 650                 goto out;
 651         }
 652
 653         printf("Vno  Type                                        Principal\n");
 654
 655         while (krb5_kt_next_entry(context, keytab, &kt_entry, &cursor) == 0) {
 656
 657                 char *princ_s = NULL;
 658                 char *etype_s = NULL;
 659                 krb5_enctype enctype = 0;
 660
 661                 ret = smb_krb5_unparse_name(talloc_tos(), context,
 662                                             kt_entry.principal, &princ_s);
 663                 if (ret) {
 664                         goto out;
 665                 }
 666
 667                 enctype = smb_krb5_kt_get_enctype_from_entry(&kt_entry);
 668
 669                 ret = smb_krb5_enctype_to_string(context, enctype, &etype_s);
 670                 if (ret &&
 671                     (asprintf(&etype_s, "UNKNOWN: %d\n", enctype) == -1)) {
 672                         TALLOC_FREE(princ_s);
 673                         goto out;
 674                 }
 675
 676                 printf("%3d  %-43s %s\n", kt_entry.vno, etype_s, princ_s);
 677
 678                 TALLOC_FREE(princ_s);
 679                 SAFE_FREE(etype_s);
 680
 681                 ret = smb_krb5_kt_free_entry(context, &kt_entry);
 682                 if (ret) {
 683                         goto out;
 684                 }
 685         }
 686
 687         ret = krb5_kt_end_seq_get(context, keytab, &cursor);
 688         if (ret) {
 689                 goto out;
 690         }
 691
 692         /* Ensure we don't double free. */
 693         ZERO_STRUCT(kt_entry);
 694         ZERO_STRUCT(cursor);
 695 out:
 696
 697         if (!all_zero((uint8_t *)&kt_entry, sizeof(kt_entry))) {
 698                 smb_krb5_kt_free_entry(context, &kt_entry);
 699         }
 700         if (!all_zero((uint8_t *)&cursor, sizeof(cursor)) && keytab) {
 701                 krb5_kt_end_seq_get(context, keytab, &cursor);
 702         }
 703
 704         if (keytab) {
 705                 krb5_kt_close(context, keytab);
 706         }
 707         if (context) {
 708                 krb5_free_context(context);
 709         }
 710         return ret;
 711 }
 712
 713 #endif /* HAVE_KRB5 */