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 3 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, see <http://www.gnu.org/licenses/>.
  21 */
  22
  23 #include "includes.h"
  24 #include "system/kerberos.h"
  25 #include "auth/kerberos/kerberos.h"
  26 #include "auth/credentials/credentials.h"
  27 #include "auth/credentials/credentials_proto.h"
  28 #include "auth/credentials/credentials_krb5.h"
  29
  30 struct principal_container {
  31         struct smb_krb5_context *smb_krb5_context;
  32         krb5_principal principal;
  33 };
  34
  35 static int free_principal(struct principal_container *pc)
  36 {
  37         /* current heimdal - 0.6.3, which we need anyway, fixes segfaults here */
  38         krb5_free_principal(pc->smb_krb5_context->krb5_context, pc->principal);
  39
  40         return 0;
  41 }
  42
  43 static krb5_error_code salt_principal_from_credentials(TALLOC_CTX *parent_ctx,
  44                                                        struct cli_credentials *machine_account,
  45                                                        struct smb_krb5_context *smb_krb5_context,
  46                                                        krb5_principal *salt_princ)
  47 {
  48         krb5_error_code ret;
  49         char *machine_username;
  50         char *salt_body;
  51         char *lower_realm;
  52         const char *salt_principal;
  53         struct principal_container *mem_ctx = talloc(parent_ctx, struct principal_container);
  54         if (!mem_ctx) {
  55                 return ENOMEM;
  56         }
  57
  58         salt_principal = cli_credentials_get_salt_principal(machine_account);
  59         if (salt_principal) {
  60                 ret = krb5_parse_name(smb_krb5_context->krb5_context, salt_principal, salt_princ);
  61         } else {
  62                 machine_username = talloc_strdup(mem_ctx, cli_credentials_get_username(machine_account));
  63
  64                 if (!machine_username) {
  65                         talloc_free(mem_ctx);
  66                         return ENOMEM;
  67                 }
  68
  69                 if (machine_username[strlen(machine_username)-1] == '$') {
  70                         machine_username[strlen(machine_username)-1] = '\0';
  71                 }
  72                 lower_realm = strlower_talloc(mem_ctx, cli_credentials_get_realm(machine_account));
  73                 if (!lower_realm) {
  74                         talloc_free(mem_ctx);
  75                         return ENOMEM;
  76                 }
  77
  78                 salt_body = talloc_asprintf(mem_ctx, "%s.%s", machine_username,
  79                                             lower_realm);
  80                 if (!salt_body) {
  81                         talloc_free(mem_ctx);
  82                 return ENOMEM;
  83                 }
  84
  85                 ret = krb5_make_principal(smb_krb5_context->krb5_context, salt_princ,
  86                                           cli_credentials_get_realm(machine_account),
  87                                           "host", salt_body, NULL);
  88         }
  89
  90         if (ret == 0) {
  91                 /* This song-and-dance effectivly puts the principal
  92                  * into talloc, so we can't loose it. */
  93                 mem_ctx->smb_krb5_context = talloc_reference(mem_ctx, smb_krb5_context);
  94                 mem_ctx->principal = *salt_princ;
  95                 talloc_set_destructor(mem_ctx, free_principal);
  96         }
  97         return ret;
  98 }
  99
 100 /* Obtain the principal set on this context.  Requires a
 101  * smb_krb5_context because we are doing krb5 principal parsing with
 102  * the library routines.  The returned princ is placed in the talloc
 103  * system by means of a destructor (do *not* free). */
 104
 105  krb5_error_code principal_from_credentials(TALLOC_CTX *parent_ctx,
 106                                             struct cli_credentials *credentials,
 107                                             struct smb_krb5_context *smb_krb5_context,
 108                                             krb5_principal *princ)
 109 {
 110         krb5_error_code ret;
 111         const char *princ_string;
 112         struct principal_container *mem_ctx = talloc(parent_ctx, struct principal_container);
 113         if (!mem_ctx) {
 114                 return ENOMEM;
 115         }
 116
 117         princ_string = cli_credentials_get_principal(credentials, mem_ctx);
 118
 119         /* A NULL here has meaning, as the gssapi server case will
 120          * then use the principal from the client */
 121         if (!princ_string) {
 122                 talloc_free(mem_ctx);
 123                 princ = NULL;
 124                 return 0;
 125         }
 126
 127         ret = krb5_parse_name(smb_krb5_context->krb5_context,
 128                               princ_string, princ);
 129
 130         if (ret == 0) {
 131                 /* This song-and-dance effectivly puts the principal
 132                  * into talloc, so we can't loose it. */
 133                 mem_ctx->smb_krb5_context = talloc_reference(mem_ctx, smb_krb5_context);
 134                 mem_ctx->principal = *princ;
 135                 talloc_set_destructor(mem_ctx, free_principal);
 136         }
 137         return ret;
 138 }
 139
 140 /**
 141  * Return a freshly allocated ccache (destroyed by destructor on child
 142  * of parent_ctx), for a given set of client credentials
 143  */
 144
 145  krb5_error_code kinit_to_ccache(TALLOC_CTX *parent_ctx,
 146                                  struct cli_credentials *credentials,
 147                                  struct smb_krb5_context *smb_krb5_context,
 148                                  krb5_ccache ccache)
 149 {
 150         krb5_error_code ret;
 151         const char *password;
 152         time_t kdc_time = 0;
 153         krb5_principal princ;
 154         int tries;
 155         TALLOC_CTX *mem_ctx = talloc_new(parent_ctx);
 156
 157         if (!mem_ctx) {
 158                 return ENOMEM;
 159         }
 160
 161         ret = principal_from_credentials(mem_ctx, credentials, smb_krb5_context, &princ);
 162         if (ret) {
 163                 talloc_free(mem_ctx);
 164                 return ret;
 165         }
 166
 167         password = cli_credentials_get_password(credentials);
 168
 169         tries = 2;
 170         while (tries--) {
 171                 if (password) {
 172                         ret = kerberos_kinit_password_cc(smb_krb5_context->krb5_context, ccache,
 173                                                          princ,
 174                                                          password, NULL, &kdc_time);
 175                 } else {
 176                         /* No password available, try to use a keyblock instead */
 177
 178                         krb5_keyblock keyblock;
 179                         const struct samr_Password *mach_pwd;
 180                         mach_pwd = cli_credentials_get_nt_hash(credentials, mem_ctx);
 181                         if (!mach_pwd) {
 182                                 talloc_free(mem_ctx);
 183                                 DEBUG(1, ("kinit_to_ccache: No password available for kinit\n"));
 184                                 return EINVAL;
 185                         }
 186                         ret = krb5_keyblock_init(smb_krb5_context->krb5_context,
 187                                                  ETYPE_ARCFOUR_HMAC_MD5,
 188                                                  mach_pwd->hash, sizeof(mach_pwd->hash),
 189                                                  &keyblock);
 190
 191                         if (ret == 0) {
 192                                 ret = kerberos_kinit_keyblock_cc(smb_krb5_context->krb5_context, ccache,
 193                                                                  princ,
 194                                                                  &keyblock, NULL, &kdc_time);
 195                                 krb5_free_keyblock_contents(smb_krb5_context->krb5_context, &keyblock);
 196                         }
 197                 }
 198
 199                 if (ret == KRB5KRB_AP_ERR_SKEW || ret == KRB5_KDCREP_SKEW) {
 200                         /* Perhaps we have been given an invalid skew, so try again without it */
 201                         time_t t = time(NULL);
 202                         krb5_set_real_time(smb_krb5_context->krb5_context, t, 0);
 203                 } else {
 204                         /* not a skew problem */
 205                         break;
 206                 }
 207         }
 208
 209         if (ret == KRB5KRB_AP_ERR_SKEW || ret == KRB5_KDCREP_SKEW) {
 210                 DEBUG(1,("kinit for %s failed (%s)\n",
 211                          cli_credentials_get_principal(credentials, mem_ctx),
 212                          smb_get_krb5_error_message(smb_krb5_context->krb5_context,
 213                                                     ret, mem_ctx)));
 214                 talloc_free(mem_ctx);
 215                 return ret;
 216         }
 217
 218         /* cope with ticket being in the future due to clock skew */
 219         if ((unsigned)kdc_time > time(NULL)) {
 220                 time_t t = time(NULL);
 221                 int time_offset =(unsigned)kdc_time-t;
 222                 DEBUG(4,("Advancing clock by %d seconds to cope with clock skew\n", time_offset));
 223                 krb5_set_real_time(smb_krb5_context->krb5_context, t + time_offset + 1, 0);
 224         }
 225
 226         if (ret == KRB5KDC_ERR_PREAUTH_FAILED && cli_credentials_wrong_password(credentials)) {
 227                 ret = kinit_to_ccache(parent_ctx,
 228                                       credentials,
 229                                       smb_krb5_context,
 230                                       ccache);
 231         }
 232         if (ret) {
 233                 DEBUG(1,("kinit for %s failed (%s)\n",
 234                          cli_credentials_get_principal(credentials, mem_ctx),
 235                          smb_get_krb5_error_message(smb_krb5_context->krb5_context,
 236                                                     ret, mem_ctx)));
 237                 talloc_free(mem_ctx);
 238                 return ret;
 239         }
 240         talloc_free(mem_ctx);
 241         return 0;
 242 }
 243
 244 static int free_keytab(struct keytab_container *ktc)
 245 {
 246         krb5_kt_close(ktc->smb_krb5_context->krb5_context, ktc->keytab);
 247
 248         return 0;
 249 }
 250
 251 int smb_krb5_open_keytab(TALLOC_CTX *mem_ctx,
 252                          struct smb_krb5_context *smb_krb5_context,
 253                          const char *keytab_name, struct keytab_container **ktc)
 254 {
 255         krb5_keytab keytab;
 256         int ret;
 257         ret = krb5_kt_resolve(smb_krb5_context->krb5_context, keytab_name, &keytab);
 258         if (ret) {
 259                 DEBUG(1,("failed to open krb5 keytab: %s\n",
 260                          smb_get_krb5_error_message(smb_krb5_context->krb5_context,
 261                                                     ret, mem_ctx)));
 262                 return ret;
 263         }
 264
 265         *ktc = talloc(mem_ctx, struct keytab_container);
 266         if (!*ktc) {
 267                 return ENOMEM;
 268         }
 269
 270         (*ktc)->smb_krb5_context = talloc_reference(*ktc, smb_krb5_context);
 271         (*ktc)->keytab = keytab;
 272         talloc_set_destructor(*ktc, free_keytab);
 273
 274         return 0;
 275 }
 276
 277 static krb5_error_code keytab_add_keys(TALLOC_CTX *parent_ctx,
 278                                        const char *princ_string,
 279                                        krb5_principal princ,
 280                                        krb5_principal salt_princ,
 281                                        int kvno,
 282                                        const char *password_s,
 283                                        struct smb_krb5_context *smb_krb5_context,
 284                                        const char **enctype_strings,
 285                                        krb5_keytab keytab)
 286 {
 287         int i;
 288         krb5_error_code ret;
 289         krb5_data password;
 290         TALLOC_CTX *mem_ctx = talloc_new(parent_ctx);
 291         if (!mem_ctx) {
 292                 return ENOMEM;
 293         }
 294
 295         password.data = discard_const_p(char *, password_s);
 296         password.length = strlen(password_s);
 297
 298         for (i=0; enctype_strings[i]; i++) {
 299                 krb5_keytab_entry entry;
 300                 krb5_enctype enctype;
 301                 ret = krb5_string_to_enctype(smb_krb5_context->krb5_context, enctype_strings[i], &enctype);
 302                 if (ret != 0) {
 303                         DEBUG(1, ("Failed to interpret %s as a krb5 encryption type: %s\n",
 304                                   enctype_strings[i],
 305                                   smb_get_krb5_error_message(smb_krb5_context->krb5_context,
 306                                                              ret, mem_ctx)));
 307                         talloc_free(mem_ctx);
 308                         return ret;
 309                 }
 310                 ret = create_kerberos_key_from_string(smb_krb5_context->krb5_context,
 311                                                       salt_princ, &password, &entry.keyblock, enctype);
 312                 if (ret != 0) {
 313                         talloc_free(mem_ctx);
 314                         return ret;
 315                 }
 316
 317                 entry.principal = princ;
 318                 entry.vno       = kvno;
 319                 ret = krb5_kt_add_entry(smb_krb5_context->krb5_context, keytab, &entry);
 320                 if (ret != 0) {
 321                         DEBUG(1, ("Failed to add %s entry for %s(kvno %d) to keytab: %s\n",
 322                                   enctype_strings[i],
 323                                   princ_string,
 324                                   kvno,
 325                                   smb_get_krb5_error_message(smb_krb5_context->krb5_context,
 326                                                              ret, mem_ctx)));
 327                         talloc_free(mem_ctx);
 328                         krb5_free_keyblock_contents(smb_krb5_context->krb5_context, &entry.keyblock);
 329                         return ret;
 330                 }
 331
 332                 DEBUG(5, ("Added %s(kvno %d) to keytab (%s)\n",
 333                           princ_string, kvno,
 334                           enctype_strings[i]));
 335
 336                 krb5_free_keyblock_contents(smb_krb5_context->krb5_context, &entry.keyblock);
 337         }
 338         talloc_free(mem_ctx);
 339         return 0;
 340 }
 341
 342 static int create_keytab(TALLOC_CTX *parent_ctx,
 343                          struct cli_credentials *machine_account,
 344                          struct smb_krb5_context *smb_krb5_context,
 345                          const char **enctype_strings,
 346                          krb5_keytab keytab,
 347                          bool add_old)
 348 {
 349         krb5_error_code ret;
 350         const char *password_s;
 351         const char *old_secret;
 352         int kvno;
 353         krb5_principal salt_princ;
 354         krb5_principal princ;
 355         const char *princ_string;
 356
 357         TALLOC_CTX *mem_ctx = talloc_new(parent_ctx);
 358         if (!mem_ctx) {
 359                 return ENOMEM;
 360         }
 361
 362         princ_string = cli_credentials_get_principal(machine_account, mem_ctx);
 363         /* Get the principal we will store the new keytab entries under */
 364         ret = principal_from_credentials(mem_ctx, machine_account, smb_krb5_context, &princ);
 365         if (ret) {
 366                 DEBUG(1,("create_keytab: makeing krb5 principal failed (%s)\n",
 367                          smb_get_krb5_error_message(smb_krb5_context->krb5_context,
 368                                                     ret, mem_ctx)));
 369                 talloc_free(mem_ctx);
 370                 return ret;
 371         }
 372
 373         /* The salt used to generate these entries may be different however, fetch that */
 374         ret = salt_principal_from_credentials(mem_ctx, machine_account,
 375                                               smb_krb5_context,
 376                                               &salt_princ);
 377         if (ret) {
 378                 DEBUG(1,("create_keytab: makeing salt principal failed (%s)\n",
 379                          smb_get_krb5_error_message(smb_krb5_context->krb5_context,
 380                                                     ret, mem_ctx)));
 381                 talloc_free(mem_ctx);
 382                 return ret;
 383         }
 384
 385         /* Finally, do the dance to get the password to put in the entry */
 386         password_s = cli_credentials_get_password(machine_account);
 387         if (!password_s) {
 388                 krb5_keytab_entry entry;
 389                 const struct samr_Password *mach_pwd;
 390
 391                 if (!str_list_check(enctype_strings, "arcfour-hmac-md5")) {
 392                         DEBUG(1, ("Asked to create keytab, but with only an NT hash supplied, "
 393                                   "but not listing arcfour-hmac-md5 as an enc type to include in the keytab!\n"));
 394                         talloc_free(mem_ctx);
 395                         return EINVAL;
 396                 }
 397
 398                 /* If we don't have the plaintext password, try for
 399                  * the MD4 password hash */
 400                 mach_pwd = cli_credentials_get_nt_hash(machine_account, mem_ctx);
 401                 if (!mach_pwd) {
 402                         /* OK, nothing to do here */
 403                         talloc_free(mem_ctx);
 404                         return 0;
 405                 }
 406                 ret = krb5_keyblock_init(smb_krb5_context->krb5_context,
 407                                          ETYPE_ARCFOUR_HMAC_MD5,
 408                                          mach_pwd->hash, sizeof(mach_pwd->hash),
 409                                          &entry.keyblock);
 410                 if (ret) {
 411                         DEBUG(1, ("create_keytab: krb5_keyblock_init failed: %s\n",
 412                                   smb_get_krb5_error_message(smb_krb5_context->krb5_context,
 413                                                              ret, mem_ctx)));
 414                         talloc_free(mem_ctx);
 415                         return ret;
 416                 }
 417
 418                 entry.principal = princ;
 419                 entry.vno       = cli_credentials_get_kvno(machine_account);
 420                 ret = krb5_kt_add_entry(smb_krb5_context->krb5_context, keytab, &entry);
 421                 if (ret) {
 422                         DEBUG(1, ("Failed to add ARCFOUR_HMAC (only) entry for %s to keytab: %s",
 423                                   cli_credentials_get_principal(machine_account, mem_ctx),
 424                                   smb_get_krb5_error_message(smb_krb5_context->krb5_context,
 425                                                              ret, mem_ctx)));
 426                         talloc_free(mem_ctx);
 427                         krb5_free_keyblock_contents(smb_krb5_context->krb5_context, &entry.keyblock);
 428                         return ret;
 429                 }
 430
 431                 DEBUG(5, ("Added %s(kvno %d) to keytab (arcfour-hmac-md5)\n",
 432                           cli_credentials_get_principal(machine_account, mem_ctx),
 433                           cli_credentials_get_kvno(machine_account)));
 434
 435                 krb5_free_keyblock_contents(smb_krb5_context->krb5_context, &entry.keyblock);
 436
 437                 /* Can't go any further, we only have this one key */
 438                 talloc_free(mem_ctx);
 439                 return 0;
 440         }
 441
 442         kvno = cli_credentials_get_kvno(machine_account);
 443         /* good, we actually have the real plaintext */
 444         ret = keytab_add_keys(mem_ctx, princ_string, princ, salt_princ,
 445                               kvno, password_s, smb_krb5_context,
 446                               enctype_strings, keytab);
 447         if (!ret) {
 448                 talloc_free(mem_ctx);
 449                 return ret;
 450         }
 451
 452         if (!add_old || kvno == 0) {
 453                 talloc_free(mem_ctx);
 454                 return 0;
 455         }
 456
 457         old_secret = cli_credentials_get_old_password(machine_account);
 458         if (!old_secret) {
 459                 talloc_free(mem_ctx);
 460                 return 0;
 461         }
 462
 463         ret = keytab_add_keys(mem_ctx, princ_string, princ, salt_princ,
 464                               kvno - 1, old_secret, smb_krb5_context,
 465                               enctype_strings, keytab);
 466         if (!ret) {
 467                 talloc_free(mem_ctx);
 468                 return ret;
 469         }
 470
 471         talloc_free(mem_ctx);
 472         return 0;
 473 }
 474
 475
 476 /*
 477  * Walk the keytab, looking for entries of this principal name, with KVNO other than current kvno -1.
 478  *
 479  * These entries are now stale, we only keep the current, and previous entries around.
 480  *
 481  * Inspired by the code in Samba3 for 'use kerberos keytab'.
 482  *
 483  */
 484
 485 static krb5_error_code remove_old_entries(TALLOC_CTX *parent_ctx,
 486                                           struct cli_credentials *machine_account,
 487                                           struct smb_krb5_context *smb_krb5_context,
 488                                           krb5_keytab keytab, bool *found_previous)
 489 {
 490         krb5_error_code ret, ret2;
 491         krb5_kt_cursor cursor;
 492         krb5_principal princ;
 493         int kvno;
 494         TALLOC_CTX *mem_ctx = talloc_new(parent_ctx);
 495         const char *princ_string;
 496         if (!mem_ctx) {
 497                 return ENOMEM;
 498         }
 499
 500         *found_previous = false;
 501         princ_string = cli_credentials_get_principal(machine_account, mem_ctx);
 502
 503         /* Get the principal we will store the new keytab entries under */
 504         ret = principal_from_credentials(mem_ctx, machine_account, smb_krb5_context, &princ);
 505         if (ret) {
 506                 DEBUG(1,("update_keytab: makeing krb5 principal failed (%s)\n",
 507                          smb_get_krb5_error_message(smb_krb5_context->krb5_context,
 508                                                     ret, mem_ctx)));
 509                 talloc_free(mem_ctx);
 510                 return ret;
 511         }
 512
 513         kvno = cli_credentials_get_kvno(machine_account);
 514
 515         /* for each entry in the keytab */
 516         ret = krb5_kt_start_seq_get(smb_krb5_context->krb5_context, keytab, &cursor);
 517         switch (ret) {
 518         case 0:
 519                 break;
 520         case HEIM_ERR_OPNOTSUPP:
 521         case ENOENT:
 522         case KRB5_KT_END:
 523                 /* no point enumerating if there isn't anything here */
 524                 talloc_free(mem_ctx);
 525                 return 0;
 526         default:
 527                 DEBUG(1,("failed to open keytab for read of old entries: %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         while (!ret) {
 535                 krb5_keytab_entry entry;
 536                 ret = krb5_kt_next_entry(smb_krb5_context->krb5_context, keytab, &entry, &cursor);
 537                 if (ret) {
 538                         break;
 539                 }
 540                 /* if it matches our principal */
 541                 if (!krb5_kt_compare(smb_krb5_context->krb5_context, &entry, princ, 0, 0)) {
 542                         /* Free the entry, it wasn't the one we were looking for anyway */
 543                         krb5_kt_free_entry(smb_krb5_context->krb5_context, &entry);
 544                         continue;
 545                 }
 546
 547                 /* delete it, if it is not kvno -1 */
 548                 if (entry.vno != (kvno - 1 )) {
 549                         /* Release the enumeration.  We are going to
 550                          * have to start this from the top again,
 551                          * because deletes during enumeration may not
 552                          * always be consistant.
 553                          *
 554                          * Also, the enumeration locks a FILE: keytab
 555                          */
 556
 557                         krb5_kt_end_seq_get(smb_krb5_context->krb5_context, keytab, &cursor);
 558
 559                         ret = krb5_kt_remove_entry(smb_krb5_context->krb5_context, keytab, &entry);
 560                         krb5_kt_free_entry(smb_krb5_context->krb5_context, &entry);
 561
 562                         /* Deleted: Restart from the top */
 563                         ret2 = krb5_kt_start_seq_get(smb_krb5_context->krb5_context, keytab, &cursor);
 564                         if (ret2) {
 565                                 krb5_kt_free_entry(smb_krb5_context->krb5_context, &entry);
 566                                 DEBUG(1,("failed to restart enumeration of keytab: %s\n",
 567                                          smb_get_krb5_error_message(smb_krb5_context->krb5_context,
 568                                                                     ret, mem_ctx)));
 569
 570                                 talloc_free(mem_ctx);
 571                                 return ret2;
 572                         }
 573
 574                         if (ret) {
 575                                 break;
 576                         }
 577
 578                 } else {
 579                         *found_previous = true;
 580                 }
 581
 582                 /* Free the entry, we don't need it any more */
 583                 krb5_kt_free_entry(smb_krb5_context->krb5_context, &entry);
 584
 585
 586         }
 587         krb5_kt_end_seq_get(smb_krb5_context->krb5_context, keytab, &cursor);
 588
 589         switch (ret) {
 590         case 0:
 591                 break;
 592         case ENOENT:
 593         case KRB5_KT_END:
 594                 ret = 0;
 595                 break;
 596         default:
 597                 DEBUG(1,("failed in deleting old entries for principal: %s: %s\n",
 598                          princ_string,
 599                          smb_get_krb5_error_message(smb_krb5_context->krb5_context,
 600                                                     ret, mem_ctx)));
 601         }
 602         talloc_free(mem_ctx);
 603         return ret;
 604 }
 605
 606 int smb_krb5_update_keytab(TALLOC_CTX *parent_ctx,
 607                            struct cli_credentials *machine_account,
 608                            struct smb_krb5_context *smb_krb5_context,
 609                            const char **enctype_strings,
 610                            struct keytab_container *keytab_container)
 611 {
 612         krb5_error_code ret;
 613         bool found_previous;
 614         TALLOC_CTX *mem_ctx = talloc_new(parent_ctx);
 615         if (!mem_ctx) {
 616                 return ENOMEM;
 617         }
 618
 619         ret = remove_old_entries(mem_ctx, machine_account,
 620                                  smb_krb5_context, keytab_container->keytab, &found_previous);
 621         if (ret != 0) {
 622                 talloc_free(mem_ctx);
 623                 return ret;
 624         }
 625
 626         /* Create a new keytab.  If during the cleanout we found
 627          * entires for kvno -1, then don't try and duplicate them.
 628          * Otherwise, add kvno, and kvno -1 */
 629
 630         ret = create_keytab(mem_ctx, machine_account, smb_krb5_context,
 631                             enctype_strings,
 632                             keytab_container->keytab,
 633                             found_previous ? false : true);
 634         talloc_free(mem_ctx);
 635         return ret;
 636 }
 637
 638 int smb_krb5_create_memory_keytab(TALLOC_CTX *parent_ctx,
 639                                            struct cli_credentials *machine_account,
 640                                            struct smb_krb5_context *smb_krb5_context,
 641                                            const char **enctype_strings,
 642                                            struct keytab_container **keytab_container)
 643 {
 644         krb5_error_code ret;
 645         TALLOC_CTX *mem_ctx = talloc_new(parent_ctx);
 646         const char *rand_string;
 647         const char *keytab_name;
 648         if (!mem_ctx) {
 649                 return ENOMEM;
 650         }
 651
 652         *keytab_container = talloc(mem_ctx, struct keytab_container);
 653
 654         rand_string = generate_random_str(mem_ctx, 16);
 655         if (!rand_string) {
 656                 talloc_free(mem_ctx);
 657                 return ENOMEM;
 658         }
 659
 660         keytab_name = talloc_asprintf(mem_ctx, "MEMORY:%s",
 661                                       rand_string);
 662         if (!keytab_name) {
 663                 talloc_free(mem_ctx);
 664                 return ENOMEM;
 665         }
 666
 667         ret = smb_krb5_open_keytab(mem_ctx, smb_krb5_context, keytab_name, keytab_container);
 668         if (ret) {
 669                 return ret;
 670         }
 671
 672         ret = smb_krb5_update_keytab(mem_ctx, machine_account, smb_krb5_context, enctype_strings, *keytab_container);
 673         if (ret == 0) {
 674                 talloc_steal(parent_ctx, *keytab_container);
 675         } else {
 676                 *keytab_container = NULL;
 677         }
 678         talloc_free(mem_ctx);
 679         return ret;
 680 }
 681