source4/auth/kerberos/kerberos_util.c

   1 /*
   2    Unix SMB/CIFS implementation.
   3
   4    Kerberos utility functions for GENSEC
   5
   6    Copyright (C) Andrew Bartlett <abartlet@samba.org> 2004-2005
   7
   8    This program is free software; you can redistribute it and/or modify
   9    it under the terms of the GNU General Public License as published by
  10    the Free Software Foundation; either version 2 of the License, or
  11    (at your option) any later version.
  12
  13    This program is distributed in the hope that it will be useful,
  14    but WITHOUT ANY WARRANTY; without even the implied warranty of
  15    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16    GNU General Public License for more details.
  17
  18
  19    You should have received a copy of the GNU General Public License
  20    along with this program; if not, write to the Free Software
  21    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  22 */
  23
  24 #include "includes.h"
  25 #include "system/kerberos.h"
  26 #include "auth/kerberos/kerberos.h"
  27 #include "auth/credentials/credentials.h"
  28
  29 struct principal_container {
  30         struct smb_krb5_context *smb_krb5_context;
  31         krb5_principal principal;
  32 };
  33
  34 static int free_principal(struct principal_container *pc)
  35 {
  36         /* current heimdal - 0.6.3, which we need anyway, fixes segfaults here */
  37         krb5_free_principal(pc->smb_krb5_context->krb5_context, pc->principal);
  38
  39         return 0;
  40 }
  41
  42 static krb5_error_code salt_principal_from_credentials(TALLOC_CTX *parent_ctx,
  43                                                        struct cli_credentials *machine_account,
  44                                                        struct smb_krb5_context *smb_krb5_context,
  45                                                        krb5_principal *salt_princ)
  46 {
  47         krb5_error_code ret;
  48         char *machine_username;
  49         char *salt_body;
  50         char *lower_realm;
  51         const char *salt_principal;
  52         struct principal_container *mem_ctx = talloc(parent_ctx, struct principal_container);
  53         if (!mem_ctx) {
  54                 return ENOMEM;
  55         }
  56
  57         salt_principal = cli_credentials_get_salt_principal(machine_account);
  58         if (salt_principal) {
  59                 ret = krb5_parse_name(smb_krb5_context->krb5_context, salt_principal, salt_princ);
  60         } else {
  61                 machine_username = talloc_strdup(mem_ctx, cli_credentials_get_username(machine_account));
  62
  63                 if (!machine_username) {
  64                         talloc_free(mem_ctx);
  65                         return ENOMEM;
  66                 }
  67
  68                 if (machine_username[strlen(machine_username)-1] == '$') {
  69                         machine_username[strlen(machine_username)-1] = '\0';
  70                 }
  71                 lower_realm = strlower_talloc(mem_ctx, cli_credentials_get_realm(machine_account));
  72                 if (!lower_realm) {
  73                         talloc_free(mem_ctx);
  74                         return ENOMEM;
  75                 }
  76
  77                 salt_body = talloc_asprintf(mem_ctx, "%s.%s", machine_username,
  78                                             lower_realm);
  79                 if (!salt_body) {
  80                         talloc_free(mem_ctx);
  81                 return ENOMEM;
  82                 }
  83
  84                 ret = krb5_make_principal(smb_krb5_context->krb5_context, salt_princ,
  85                                           cli_credentials_get_realm(machine_account),
  86                                           "host", salt_body, NULL);
  87         }
  88
  89         if (ret == 0) {
  90                 /* This song-and-dance effectivly puts the principal
  91                  * into talloc, so we can't loose it. */
  92                 mem_ctx->smb_krb5_context = talloc_reference(mem_ctx, smb_krb5_context);
  93                 mem_ctx->principal = *salt_princ;
  94                 talloc_set_destructor(mem_ctx, free_principal);
  95         }
  96         return ret;
  97 }
  98
  99 /* Obtain the principal set on this context.  Requires a
 100  * smb_krb5_context because we are doing krb5 principal parsing with
 101  * the library routines.  The returned princ is placed in the talloc
 102  * system by means of a destructor (do *not* free). */
 103
 104 krb5_error_code principal_from_credentials(TALLOC_CTX *parent_ctx,
 105                                            struct cli_credentials *credentials,
 106                                            struct smb_krb5_context *smb_krb5_context,
 107                                            krb5_principal *princ)
 108 {
 109         krb5_error_code ret;
 110         const char *princ_string;
 111         struct principal_container *mem_ctx = talloc(parent_ctx, struct principal_container);
 112         if (!mem_ctx) {
 113                 return ENOMEM;
 114         }
 115
 116         princ_string = cli_credentials_get_principal(credentials, mem_ctx);
 117
 118         /* A NULL here has meaning, as the gssapi server case will
 119          * then use the principal from the client */
 120         if (!princ_string) {
 121                 talloc_free(mem_ctx);
 122                 princ = NULL;
 123                 return 0;
 124         }
 125
 126         ret = krb5_parse_name(smb_krb5_context->krb5_context,
 127                               princ_string, princ);
 128
 129         if (ret == 0) {
 130                 /* This song-and-dance effectivly puts the principal
 131                  * into talloc, so we can't loose it. */
 132                 mem_ctx->smb_krb5_context = talloc_reference(mem_ctx, smb_krb5_context);
 133                 mem_ctx->principal = *princ;
 134                 talloc_set_destructor(mem_ctx, free_principal);
 135         }
 136         return ret;
 137 }
 138
 139 /**
 140  * Return a freshly allocated ccache (destroyed by destructor on child
 141  * of parent_ctx), for a given set of client credentials
 142  */
 143
 144  krb5_error_code kinit_to_ccache(TALLOC_CTX *parent_ctx,
 145                                  struct cli_credentials *credentials,
 146                                  struct smb_krb5_context *smb_krb5_context,
 147                                  krb5_ccache ccache)
 148 {
 149         krb5_error_code ret;
 150         const char *password;
 151         time_t kdc_time = 0;
 152         krb5_principal princ;
 153         int tries;
 154         TALLOC_CTX *mem_ctx = talloc_new(parent_ctx);
 155
 156         if (!mem_ctx) {
 157                 return ENOMEM;
 158         }
 159
 160         ret = principal_from_credentials(mem_ctx, credentials, smb_krb5_context, &princ);
 161         if (ret) {
 162                 talloc_free(mem_ctx);
 163                 return ret;
 164         }
 165
 166         password = cli_credentials_get_password(credentials);
 167
 168         tries = 2;
 169         while (tries--) {
 170                 if (password) {
 171                         ret = kerberos_kinit_password_cc(smb_krb5_context->krb5_context, ccache,
 172                                                          princ,
 173                                                          password, NULL, &kdc_time);
 174                 } else {
 175                         /* No password available, try to use a keyblock instead */
 176
 177                         krb5_keyblock keyblock;
 178                         const struct samr_Password *mach_pwd;
 179                         mach_pwd = cli_credentials_get_nt_hash(credentials, mem_ctx);
 180                         if (!mach_pwd) {
 181                                 talloc_free(mem_ctx);
 182                                 DEBUG(1, ("kinit_to_ccache: No password available for kinit\n"));
 183                                 return EINVAL;
 184                         }
 185                         ret = krb5_keyblock_init(smb_krb5_context->krb5_context,
 186                                                  ETYPE_ARCFOUR_HMAC_MD5,
 187                                                  mach_pwd->hash, sizeof(mach_pwd->hash),
 188                                                  &keyblock);
 189
 190                         if (ret == 0) {
 191                                 ret = kerberos_kinit_keyblock_cc(smb_krb5_context->krb5_context, ccache,
 192                                                                  princ,
 193                                                                  &keyblock, NULL, &kdc_time);
 194                                 krb5_free_keyblock_contents(smb_krb5_context->krb5_context, &keyblock);
 195                         }
 196                 }
 197
 198                 if (ret == KRB5KRB_AP_ERR_SKEW || ret == KRB5_KDCREP_SKEW) {
 199                         /* Perhaps we have been given an invalid skew, so try again without it */
 200                         time_t t = time(NULL);
 201                         krb5_set_real_time(smb_krb5_context->krb5_context, t, 0);
 202                 } else {
 203                         /* not a skew problem */
 204                         break;
 205                 }
 206         }
 207
 208         if (ret == KRB5KRB_AP_ERR_SKEW || ret == KRB5_KDCREP_SKEW) {
 209                 DEBUG(1,("kinit for %s failed (%s)\n",
 210                          cli_credentials_get_principal(credentials, mem_ctx),
 211                          smb_get_krb5_error_message(smb_krb5_context->krb5_context,
 212                                                     ret, mem_ctx)));
 213                 talloc_free(mem_ctx);
 214                 return ret;
 215         }
 216
 217         /* cope with ticket being in the future due to clock skew */
 218         if ((unsigned)kdc_time > time(NULL)) {
 219                 time_t t = time(NULL);
 220                 int time_offset =(unsigned)kdc_time-t;
 221                 DEBUG(4,("Advancing clock by %d seconds to cope with clock skew\n", time_offset));
 222                 krb5_set_real_time(smb_krb5_context->krb5_context, t + time_offset + 1, 0);
 223         }
 224
 225         if (ret == KRB5KDC_ERR_PREAUTH_FAILED && cli_credentials_wrong_password(credentials)) {
 226                 ret = kinit_to_ccache(parent_ctx,
 227                                       credentials,
 228                                       smb_krb5_context,
 229                                       ccache);
 230         }
 231         if (ret) {
 232                 DEBUG(1,("kinit for %s failed (%s)\n",
 233                          cli_credentials_get_principal(credentials, mem_ctx),
 234                          smb_get_krb5_error_message(smb_krb5_context->krb5_context,
 235                                                     ret, mem_ctx)));
 236                 talloc_free(mem_ctx);
 237                 return ret;
 238         }
 239         return 0;
 240 }
 241
 242 static int free_keytab(struct keytab_container *ktc)
 243 {
 244         krb5_kt_close(ktc->smb_krb5_context->krb5_context, ktc->keytab);
 245
 246         return 0;
 247 }
 248
 249 int smb_krb5_open_keytab(TALLOC_CTX *mem_ctx,
 250                          struct smb_krb5_context *smb_krb5_context,
 251                          const char *keytab_name, struct keytab_container **ktc)
 252 {
 253         krb5_keytab keytab;
 254         int ret;
 255         ret = krb5_kt_resolve(smb_krb5_context->krb5_context, keytab_name, &keytab);
 256         if (ret) {
 257                 DEBUG(1,("failed to open krb5 keytab: %s\n",
 258                          smb_get_krb5_error_message(smb_krb5_context->krb5_context,
 259                                                     ret, mem_ctx)));
 260                 return ret;
 261         }
 262
 263         *ktc = talloc(mem_ctx, struct keytab_container);
 264         if (!*ktc) {
 265                 return ENOMEM;
 266         }
 267
 268         (*ktc)->smb_krb5_context = talloc_reference(*ktc, smb_krb5_context);
 269         (*ktc)->keytab = keytab;
 270         talloc_set_destructor(*ktc, free_keytab);
 271
 272         return 0;
 273 }
 274
 275 struct enctypes_container {
 276         struct smb_krb5_context *smb_krb5_context;
 277         krb5_enctype *enctypes;
 278 };
 279
 280 static int free_enctypes(struct enctypes_container *etc)
 281 {
 282         free_kerberos_etypes(etc->smb_krb5_context->krb5_context, etc->enctypes);
 283         return 0;
 284 }
 285
 286 static krb5_error_code keytab_add_keys(TALLOC_CTX *parent_ctx,
 287                                        const char *princ_string,
 288                                        krb5_principal princ,
 289                                        krb5_principal salt_princ,
 290                                        int kvno,
 291                                        const char *password_s,
 292                                        struct smb_krb5_context *smb_krb5_context,
 293                                        krb5_keytab keytab)
 294 {
 295         int i;
 296         krb5_error_code ret;
 297         krb5_enctype *enctypes;
 298         char *enctype_string;
 299         struct enctypes_container *etc;
 300         krb5_data password;
 301         TALLOC_CTX *mem_ctx = talloc_new(parent_ctx);
 302         if (!mem_ctx) {
 303                 return ENOMEM;
 304         }
 305
 306         etc = talloc(mem_ctx, struct enctypes_container);
 307         if (!etc) {
 308                 talloc_free(mem_ctx);
 309                 return ENOMEM;
 310         }
 311         ret = get_kerberos_allowed_etypes(smb_krb5_context->krb5_context,
 312                                           &enctypes);
 313         if (ret != 0) {
 314                 DEBUG(1,("keytab_add_keys: getting encrption types failed (%s)\n",
 315                          error_message(ret)));
 316                 talloc_free(mem_ctx);
 317                 return ret;
 318         }
 319
 320         etc->smb_krb5_context = talloc_reference(etc, smb_krb5_context);
 321         etc->enctypes = enctypes;
 322
 323         talloc_set_destructor(etc, free_enctypes);
 324
 325         password.data = discard_const_p(char *, password_s);
 326         password.length = strlen(password_s);
 327
 328         for (i=0; enctypes[i]; i++) {
 329                 krb5_keytab_entry entry;
 330                 ret = create_kerberos_key_from_string(smb_krb5_context->krb5_context,
 331                                                       salt_princ, &password, &entry.keyblock, enctypes[i]);
 332                 if (ret != 0) {
 333                         talloc_free(mem_ctx);
 334                         return ret;
 335                 }
 336
 337                 entry.principal = princ;
 338                 entry.vno       = kvno;
 339                 ret = krb5_kt_add_entry(smb_krb5_context->krb5_context, keytab, &entry);
 340                 enctype_string = NULL;
 341                 krb5_enctype_to_string(smb_krb5_context->krb5_context, enctypes[i], &enctype_string);
 342                 if (ret != 0) {
 343                         DEBUG(1, ("Failed to add %s entry for %s(kvno %d) to keytab: %s\n",
 344                                   enctype_string,
 345                                   princ_string,
 346                                   kvno,
 347                                   smb_get_krb5_error_message(smb_krb5_context->krb5_context,
 348                                                              ret, mem_ctx)));
 349                         talloc_free(mem_ctx);
 350                         free(enctype_string);
 351                         krb5_free_keyblock_contents(smb_krb5_context->krb5_context, &entry.keyblock);
 352                         return ret;
 353                 }
 354
 355                 DEBUG(5, ("Added %s(kvno %d) to keytab (%s)\n",
 356                           princ_string, kvno,
 357                           enctype_string));
 358                 free(enctype_string);
 359
 360                 krb5_free_keyblock_contents(smb_krb5_context->krb5_context, &entry.keyblock);
 361         }
 362         talloc_free(mem_ctx);
 363         return 0;
 364 }
 365
 366 static int create_keytab(TALLOC_CTX *parent_ctx,
 367                          struct cli_credentials *machine_account,
 368                          struct smb_krb5_context *smb_krb5_context,
 369                          krb5_keytab keytab,
 370                          BOOL add_old)
 371 {
 372         krb5_error_code ret;
 373         const char *password_s;
 374         char *enctype_string;
 375         const char *old_secret;
 376         int kvno;
 377         krb5_principal salt_princ;
 378         krb5_principal princ;
 379         const char *princ_string;
 380
 381         TALLOC_CTX *mem_ctx = talloc_new(parent_ctx);
 382         if (!mem_ctx) {
 383                 return ENOMEM;
 384         }
 385
 386         princ_string = cli_credentials_get_principal(machine_account, mem_ctx);
 387         /* Get the principal we will store the new keytab entries under */
 388         ret = principal_from_credentials(mem_ctx, machine_account, smb_krb5_context, &princ);
 389         if (ret) {
 390                 DEBUG(1,("create_keytab: makeing krb5 principal failed (%s)\n",
 391                          smb_get_krb5_error_message(smb_krb5_context->krb5_context,
 392                                                     ret, mem_ctx)));
 393                 talloc_free(mem_ctx);
 394                 return ret;
 395         }
 396
 397         /* The salt used to generate these entries may be different however, fetch that */
 398         ret = salt_principal_from_credentials(mem_ctx, machine_account,
 399                                               smb_krb5_context,
 400                                               &salt_princ);
 401         if (ret) {
 402                 DEBUG(1,("create_keytab: makeing salt principal failed (%s)\n",
 403                          smb_get_krb5_error_message(smb_krb5_context->krb5_context,
 404                                                     ret, mem_ctx)));
 405                 talloc_free(mem_ctx);
 406                 return ret;
 407         }
 408
 409         /* Finally, do the dance to get the password to put in the entry */
 410         password_s = cli_credentials_get_password(machine_account);
 411         if (!password_s) {
 412                 /* If we don't have the plaintext password, try for
 413                  * the MD4 password hash */
 414
 415                 krb5_keytab_entry entry;
 416                 const struct samr_Password *mach_pwd;
 417                 mach_pwd = cli_credentials_get_nt_hash(machine_account, mem_ctx);
 418                 if (!mach_pwd) {
 419                         DEBUG(1, ("create_keytab: Domain trust informaton for account %s not available\n",
 420                                   cli_credentials_get_principal(machine_account, mem_ctx)));
 421                         talloc_free(mem_ctx);
 422                         return EINVAL;
 423                 }
 424                 ret = krb5_keyblock_init(smb_krb5_context->krb5_context,
 425                                          ETYPE_ARCFOUR_HMAC_MD5,
 426                                          mach_pwd->hash, sizeof(mach_pwd->hash),
 427                                          &entry.keyblock);
 428                 if (ret) {
 429                         DEBUG(1, ("create_keytab: krb5_keyblock_init failed: %s\n",
 430                                   smb_get_krb5_error_message(smb_krb5_context->krb5_context,
 431                                                              ret, mem_ctx)));
 432                         talloc_free(mem_ctx);
 433                         return ret;
 434                 }
 435
 436                 entry.principal = princ;
 437                 entry.vno       = cli_credentials_get_kvno(machine_account);
 438                 ret = krb5_kt_add_entry(smb_krb5_context->krb5_context, keytab, &entry);
 439                 if (ret) {
 440                         DEBUG(1, ("Failed to add ARCFOUR_HMAC (only) entry for %s to keytab: %s",
 441                                   cli_credentials_get_principal(machine_account, mem_ctx),
 442                                   smb_get_krb5_error_message(smb_krb5_context->krb5_context,
 443                                                              ret, mem_ctx)));
 444                         talloc_free(mem_ctx);
 445                         krb5_free_keyblock_contents(smb_krb5_context->krb5_context, &entry.keyblock);
 446                         return ret;
 447                 }
 448
 449                 krb5_enctype_to_string(smb_krb5_context->krb5_context,
 450                                        ETYPE_ARCFOUR_HMAC_MD5,
 451                                        &enctype_string);
 452                 DEBUG(5, ("Added %s(kvno %d) to keytab (%s)\n",
 453                           cli_credentials_get_principal(machine_account, mem_ctx),
 454                           cli_credentials_get_kvno(machine_account),
 455                           enctype_string));
 456                 free(enctype_string);
 457
 458                 krb5_free_keyblock_contents(smb_krb5_context->krb5_context, &entry.keyblock);
 459
 460                 /* Can't go any further, we only have this one key */
 461                 talloc_free(mem_ctx);
 462                 return 0;
 463         }
 464
 465         kvno = cli_credentials_get_kvno(machine_account);
 466         /* good, we actually have the real plaintext */
 467         ret = keytab_add_keys(mem_ctx, princ_string, princ, salt_princ,
 468                               kvno, password_s, smb_krb5_context, keytab);
 469         if (!ret) {
 470                 talloc_free(mem_ctx);
 471                 return ret;
 472         }
 473
 474         if (!add_old || kvno == 0) {
 475                 talloc_free(mem_ctx);
 476                 return 0;
 477         }
 478
 479         old_secret = cli_credentials_get_old_password(machine_account);
 480         if (!old_secret) {
 481                 talloc_free(mem_ctx);
 482                 return 0;
 483         }
 484
 485         ret = keytab_add_keys(mem_ctx, princ_string, princ, salt_princ,
 486                               kvno - 1, old_secret, smb_krb5_context, keytab);
 487         if (!ret) {
 488                 talloc_free(mem_ctx);
 489                 return ret;
 490         }
 491
 492         talloc_free(mem_ctx);
 493         return 0;
 494 }
 495
 496
 497 /*
 498  * Walk the keytab, looking for entries of this principal name, with KVNO other than current kvno -1.
 499  *
 500  * These entries are now stale, we only keep the current, and previous entries around.
 501  *
 502  * Inspired by the code in Samba3 for 'use kerberos keytab'.
 503  *
 504  */
 505
 506 static krb5_error_code remove_old_entries(TALLOC_CTX *parent_ctx,
 507                                           struct cli_credentials *machine_account,
 508                                           struct smb_krb5_context *smb_krb5_context,
 509                                           krb5_keytab keytab, BOOL *found_previous)
 510 {
 511         krb5_error_code ret, ret2;
 512         krb5_kt_cursor cursor;
 513         krb5_principal princ;
 514         int kvno;
 515         TALLOC_CTX *mem_ctx = talloc_new(parent_ctx);
 516         const char *princ_string;
 517         if (!mem_ctx) {
 518                 return ENOMEM;
 519         }
 520
 521         *found_previous = False;
 522         princ_string = cli_credentials_get_principal(machine_account, mem_ctx);
 523
 524         /* Get the principal we will store the new keytab entries under */
 525         ret = principal_from_credentials(mem_ctx, machine_account, smb_krb5_context, &princ);
 526         if (ret) {
 527                 DEBUG(1,("update_keytab: makeing krb5 principal failed (%s)\n",
 528                          smb_get_krb5_error_message(smb_krb5_context->krb5_context,
 529                                                     ret, mem_ctx)));
 530                 talloc_free(mem_ctx);
 531                 return ret;
 532         }
 533
 534         kvno = cli_credentials_get_kvno(machine_account);
 535
 536         /* for each entry in the keytab */
 537         ret = krb5_kt_start_seq_get(smb_krb5_context->krb5_context, keytab, &cursor);
 538         switch (ret) {
 539         case 0:
 540                 break;
 541         case HEIM_ERR_OPNOTSUPP:
 542         case ENOENT:
 543         case KRB5_KT_END:
 544                 /* no point enumerating if there isn't anything here */
 545                 talloc_free(mem_ctx);
 546                 return 0;
 547         default:
 548                 DEBUG(1,("failed to open keytab for read of old entries: %s\n",
 549                          smb_get_krb5_error_message(smb_krb5_context->krb5_context,
 550                                                     ret, mem_ctx)));
 551                 talloc_free(mem_ctx);
 552                 return ret;
 553         }
 554
 555         while (!ret) {
 556                 krb5_keytab_entry entry;
 557                 ret = krb5_kt_next_entry(smb_krb5_context->krb5_context, keytab, &entry, &cursor);
 558                 if (ret) {
 559                         break;
 560                 }
 561                 /* if it matches our principal */
 562                 if (!krb5_kt_compare(smb_krb5_context->krb5_context, &entry, princ, 0, 0)) {
 563                         /* Free the entry, it wasn't the one we were looking for anyway */
 564                         krb5_kt_free_entry(smb_krb5_context->krb5_context, &entry);
 565                         continue;
 566                 }
 567
 568                 /* delete it, if it is not kvno -1 */
 569                 if (entry.vno != (kvno - 1 )) {
 570                         /* Release the enumeration.  We are going to
 571                          * have to start this from the top again,
 572                          * because deletes during enumeration may not
 573                          * always be consistant.
 574                          *
 575                          * Also, the enumeration locks a FILE: keytab
 576                          */
 577
 578                         krb5_kt_end_seq_get(smb_krb5_context->krb5_context, keytab, &cursor);
 579
 580                         ret = krb5_kt_remove_entry(smb_krb5_context->krb5_context, keytab, &entry);
 581                         krb5_kt_free_entry(smb_krb5_context->krb5_context, &entry);
 582
 583                         /* Deleted: Restart from the top */
 584                         ret2 = krb5_kt_start_seq_get(smb_krb5_context->krb5_context, keytab, &cursor);
 585                         if (ret2) {
 586                                 krb5_kt_free_entry(smb_krb5_context->krb5_context, &entry);
 587                                 DEBUG(1,("failed to restart enumeration of keytab: %s\n",
 588                                          smb_get_krb5_error_message(smb_krb5_context->krb5_context,
 589                                                                     ret, mem_ctx)));
 590
 591                                 talloc_free(mem_ctx);
 592                                 return ret2;
 593                         }
 594
 595                         if (ret) {
 596                                 break;
 597                         }
 598
 599                 } else {
 600                         *found_previous = True;
 601                 }
 602
 603                 /* Free the entry, we don't need it any more */
 604                 krb5_kt_free_entry(smb_krb5_context->krb5_context, &entry);
 605
 606
 607         }
 608         krb5_kt_end_seq_get(smb_krb5_context->krb5_context, keytab, &cursor);
 609
 610         switch (ret) {
 611         case 0:
 612                 break;
 613         case ENOENT:
 614         case KRB5_KT_END:
 615                 ret = 0;
 616                 break;
 617         default:
 618                 DEBUG(1,("failed in deleting old entries for principal: %s: %s\n",
 619                          princ_string,
 620                          smb_get_krb5_error_message(smb_krb5_context->krb5_context,
 621                                                     ret, mem_ctx)));
 622         }
 623         talloc_free(mem_ctx);
 624         return ret;
 625 }
 626
 627 int smb_krb5_update_keytab(TALLOC_CTX *parent_ctx,
 628                            struct cli_credentials *machine_account,
 629                            struct smb_krb5_context *smb_krb5_context,
 630                            struct keytab_container *keytab_container)
 631 {
 632         krb5_error_code ret;
 633         BOOL found_previous;
 634         TALLOC_CTX *mem_ctx = talloc_new(parent_ctx);
 635         if (!mem_ctx) {
 636                 return ENOMEM;
 637         }
 638
 639         ret = remove_old_entries(mem_ctx, machine_account,
 640                                  smb_krb5_context, keytab_container->keytab, &found_previous);
 641         if (ret != 0) {
 642                 talloc_free(mem_ctx);
 643                 return ret;
 644         }
 645
 646         /* Create a new keytab.  If during the cleanout we found
 647          * entires for kvno -1, then don't try and duplicate them.
 648          * Otherwise, add kvno, and kvno -1 */
 649
 650         ret = create_keytab(mem_ctx, machine_account, smb_krb5_context,
 651                             keytab_container->keytab,
 652                             found_previous ? False : True);
 653         talloc_free(mem_ctx);
 654         return ret;
 655 }
 656
 657 int smb_krb5_create_memory_keytab(TALLOC_CTX *parent_ctx,
 658                                   struct cli_credentials *machine_account,
 659                                   struct smb_krb5_context *smb_krb5_context,
 660                                   struct keytab_container **keytab_container)
 661 {
 662         krb5_error_code ret;
 663         TALLOC_CTX *mem_ctx = talloc_new(parent_ctx);
 664         const char *rand_string;
 665         const char *keytab_name;
 666         if (!mem_ctx) {
 667                 return ENOMEM;
 668         }
 669
 670         *keytab_container = talloc(mem_ctx, struct keytab_container);
 671
 672         rand_string = generate_random_str(mem_ctx, 16);
 673         if (!rand_string) {
 674                 talloc_free(mem_ctx);
 675                 return ENOMEM;
 676         }
 677
 678         keytab_name = talloc_asprintf(mem_ctx, "MEMORY:%s",
 679                                       rand_string);
 680         if (!keytab_name) {
 681                 talloc_free(mem_ctx);
 682                 return ENOMEM;
 683         }
 684
 685         ret = smb_krb5_open_keytab(mem_ctx, smb_krb5_context, keytab_name, keytab_container);
 686         if (ret) {
 687                 return ret;
 688         }
 689
 690         ret = smb_krb5_update_keytab(mem_ctx, machine_account, smb_krb5_context, *keytab_container);
 691         if (ret == 0) {
 692                 talloc_steal(parent_ctx, *keytab_container);
 693         } else {
 694                 *keytab_container = NULL;
 695         }
 696         talloc_free(mem_ctx);
 697         return ret;
 698 }
 699