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/auth.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(void *ptr) {
  35         struct principal_container *pc = ptr;
  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 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
 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         if (password) {
 169                 ret = kerberos_kinit_password_cc(smb_krb5_context->krb5_context, ccache,
 170                                                  princ,
 171                                                  password, NULL, &kdc_time);
 172         } else {
 173                 /* No password available, try to use a keyblock instead */
 174
 175                 krb5_keyblock keyblock;
 176                 const struct samr_Password *mach_pwd;
 177                 mach_pwd = cli_credentials_get_nt_hash(credentials, mem_ctx);
 178                 if (!mach_pwd) {
 179                         talloc_free(mem_ctx);
 180                         DEBUG(1, ("kinit_to_ccache: No password available for kinit\n"));
 181                         return EINVAL;
 182                 }
 183                 ret = krb5_keyblock_init(smb_krb5_context->krb5_context,
 184                                          ENCTYPE_ARCFOUR_HMAC,
 185                                          mach_pwd->hash, sizeof(mach_pwd->hash),
 186                                          &keyblock);
 187
 188                 if (ret == 0) {
 189                         ret = kerberos_kinit_keyblock_cc(smb_krb5_context->krb5_context, ccache,
 190                                                          princ,
 191                                                          &keyblock, NULL, &kdc_time);
 192                         krb5_free_keyblock_contents(smb_krb5_context->krb5_context, &keyblock);
 193                 }
 194         }
 195
 196         /* cope with ticket being in the future due to clock skew */
 197         if ((unsigned)kdc_time > time(NULL)) {
 198                 time_t t = time(NULL);
 199                 int time_offset =(unsigned)kdc_time-t;
 200                 DEBUG(4,("Advancing clock by %d seconds to cope with clock skew\n", time_offset));
 201                 krb5_set_real_time(smb_krb5_context->krb5_context, t + time_offset + 1, 0);
 202         }
 203
 204         if (ret == KRB5KRB_AP_ERR_SKEW || ret == KRB5_KDCREP_SKEW) {
 205                 DEBUG(1,("kinit for %s failed (%s)\n",
 206                          cli_credentials_get_principal(credentials, mem_ctx),
 207                          smb_get_krb5_error_message(smb_krb5_context->krb5_context,
 208                                                     ret, mem_ctx)));
 209                 talloc_free(mem_ctx);
 210                 return ret;
 211         }
 212         if (ret) {
 213                 DEBUG(1,("kinit for %s failed (%s)\n",
 214                          cli_credentials_get_principal(credentials, mem_ctx),
 215                          smb_get_krb5_error_message(smb_krb5_context->krb5_context,
 216                                                     ret, mem_ctx)));
 217                 talloc_free(mem_ctx);
 218                 return ret;
 219         }
 220         return 0;
 221 }
 222
 223 static int free_keytab(void *ptr) {
 224         struct keytab_container *ktc = ptr;
 225         krb5_kt_close(ktc->smb_krb5_context->krb5_context, ktc->keytab);
 226
 227         return 0;
 228 }
 229
 230 int smb_krb5_open_keytab(TALLOC_CTX *mem_ctx,
 231                          struct smb_krb5_context *smb_krb5_context,
 232                          const char *keytab_name, struct keytab_container **ktc)
 233 {
 234         krb5_keytab keytab;
 235         int ret;
 236         ret = krb5_kt_resolve(smb_krb5_context->krb5_context, keytab_name, &keytab);
 237         if (ret) {
 238                 DEBUG(1,("failed to open krb5 keytab: %s\n",
 239                          smb_get_krb5_error_message(smb_krb5_context->krb5_context,
 240                                                     ret, mem_ctx)));
 241                 return ret;
 242         }
 243
 244         *ktc = talloc(mem_ctx, struct keytab_container);
 245         if (!*ktc) {
 246                 return ENOMEM;
 247         }
 248
 249         (*ktc)->smb_krb5_context = talloc_reference(*ktc, smb_krb5_context);
 250         (*ktc)->keytab = keytab;
 251         talloc_set_destructor(*ktc, free_keytab);
 252
 253         return 0;
 254 }
 255
 256 struct enctypes_container {
 257         struct smb_krb5_context *smb_krb5_context;
 258         krb5_enctype *enctypes;
 259 };
 260
 261 static int free_enctypes(void *ptr) {
 262         struct enctypes_container *etc = ptr;
 263         free_kerberos_etypes(etc->smb_krb5_context->krb5_context, etc->enctypes);
 264         return 0;
 265 }
 266
 267 static krb5_error_code keytab_add_keys(TALLOC_CTX *parent_ctx,
 268                                        const char *princ_string,
 269                                        krb5_principal princ,
 270                                        krb5_principal salt_princ,
 271                                        int kvno,
 272                                        const char *password_s,
 273                                        struct smb_krb5_context *smb_krb5_context,
 274                                        krb5_keytab keytab)
 275 {
 276         int i;
 277         krb5_error_code ret;
 278         krb5_enctype *enctypes;
 279         char *enctype_string;
 280         struct enctypes_container *etc;
 281         krb5_data password;
 282         TALLOC_CTX *mem_ctx = talloc_new(parent_ctx);
 283         if (!mem_ctx) {
 284                 return ENOMEM;
 285         }
 286
 287         etc = talloc(mem_ctx, struct enctypes_container);
 288         if (!etc) {
 289                 talloc_free(mem_ctx);
 290                 return ENOMEM;
 291         }
 292         ret = get_kerberos_allowed_etypes(smb_krb5_context->krb5_context,
 293                                           &enctypes);
 294         if (ret != 0) {
 295                 DEBUG(1,("keytab_add_keys: getting encrption types failed (%s)\n",
 296                          error_message(ret)));
 297                 talloc_free(mem_ctx);
 298                 return ret;
 299         }
 300
 301         etc->smb_krb5_context = talloc_reference(etc, smb_krb5_context);
 302         etc->enctypes = enctypes;
 303
 304         talloc_set_destructor(etc, free_enctypes);
 305
 306         password.data = discard_const_p(char *, password_s);
 307         password.length = strlen(password_s);
 308
 309         for (i=0; enctypes[i]; i++) {
 310                 krb5_keytab_entry entry;
 311                 ret = create_kerberos_key_from_string(smb_krb5_context->krb5_context,
 312                                                       salt_princ, &password, &entry.keyblock, enctypes[i]);
 313                 if (ret != 0) {
 314                         talloc_free(mem_ctx);
 315                         return ret;
 316                 }
 317
 318                 entry.principal = princ;
 319                 entry.vno       = kvno;
 320                 ret = krb5_kt_add_entry(smb_krb5_context->krb5_context, keytab, &entry);
 321                 enctype_string = NULL;
 322                 krb5_enctype_to_string(smb_krb5_context->krb5_context, enctypes[i], &enctype_string);
 323                 if (ret != 0) {
 324                         DEBUG(1, ("Failed to add %s entry for %s(kvno %d) to keytab: %s\n",
 325                                   enctype_string,
 326                                   princ_string,
 327                                   kvno,
 328                                   smb_get_krb5_error_message(smb_krb5_context->krb5_context,
 329                                                              ret, mem_ctx)));
 330                         talloc_free(mem_ctx);
 331                         free(enctype_string);
 332                         krb5_free_keyblock_contents(smb_krb5_context->krb5_context, &entry.keyblock);
 333                         return ret;
 334                 }
 335
 336                 DEBUG(5, ("Added %s(kvno %d) to keytab (%s)\n",
 337                           princ_string, kvno,
 338                           enctype_string));
 339                 free(enctype_string);
 340
 341                 krb5_free_keyblock_contents(smb_krb5_context->krb5_context, &entry.keyblock);
 342         }
 343         talloc_free(mem_ctx);
 344         return 0;
 345 }
 346
 347 static int create_keytab(TALLOC_CTX *parent_ctx,
 348                          struct cli_credentials *machine_account,
 349                          struct smb_krb5_context *smb_krb5_context,
 350                          krb5_keytab keytab,
 351                          BOOL add_old)
 352 {
 353         krb5_error_code ret;
 354         const char *password_s;
 355         char *enctype_string;
 356         const char *old_secret;
 357         int kvno;
 358         krb5_principal salt_princ;
 359         krb5_principal princ;
 360         const char *princ_string;
 361
 362         TALLOC_CTX *mem_ctx = talloc_new(parent_ctx);
 363         if (!mem_ctx) {
 364                 return ENOMEM;
 365         }
 366
 367         princ_string = cli_credentials_get_principal(machine_account, mem_ctx);
 368         /* Get the principal we will store the new keytab entries under */
 369         ret = principal_from_credentials(mem_ctx, machine_account, smb_krb5_context, &princ);
 370         if (ret) {
 371                 DEBUG(1,("create_keytab: makeing krb5 principal failed (%s)\n",
 372                          smb_get_krb5_error_message(smb_krb5_context->krb5_context,
 373                                                     ret, mem_ctx)));
 374                 talloc_free(mem_ctx);
 375                 return ret;
 376         }
 377
 378         /* The salt used to generate these entries may be different however, fetch that */
 379         ret = salt_principal_from_credentials(mem_ctx, machine_account,
 380                                               smb_krb5_context,
 381                                               &salt_princ);
 382         if (ret) {
 383                 DEBUG(1,("create_keytab: makeing salt principal failed (%s)\n",
 384                          smb_get_krb5_error_message(smb_krb5_context->krb5_context,
 385                                                     ret, mem_ctx)));
 386                 talloc_free(mem_ctx);
 387                 return ret;
 388         }
 389
 390         /* Finally, do the dance to get the password to put in the entry */
 391         password_s = cli_credentials_get_password(machine_account);
 392         if (!password_s) {
 393                 /* If we don't have the plaintext password, try for
 394                  * the MD4 password hash */
 395
 396                 krb5_keytab_entry entry;
 397                 const struct samr_Password *mach_pwd;
 398                 mach_pwd = cli_credentials_get_nt_hash(machine_account, mem_ctx);
 399                 if (!mach_pwd) {
 400                         DEBUG(1, ("create_keytab: Domain trust informaton for account %s not available\n",
 401                                   cli_credentials_get_principal(machine_account, mem_ctx)));
 402                         talloc_free(mem_ctx);
 403                         return EINVAL;
 404                 }
 405                 ret = krb5_keyblock_init(smb_krb5_context->krb5_context,
 406                                          ENCTYPE_ARCFOUR_HMAC,
 407                                          mach_pwd->hash, sizeof(mach_pwd->hash),
 408                                          &entry.keyblock);
 409                 if (ret) {
 410                         DEBUG(1, ("create_keytab: krb5_keyblock_init failed: %s\n",
 411                                   smb_get_krb5_error_message(smb_krb5_context->krb5_context,
 412                                                              ret, mem_ctx)));
 413                         talloc_free(mem_ctx);
 414                         return ret;
 415                 }
 416
 417                 entry.principal = princ;
 418                 entry.vno       = cli_credentials_get_kvno(machine_account);
 419                 ret = krb5_kt_add_entry(smb_krb5_context->krb5_context, keytab, &entry);
 420                 if (ret) {
 421                         DEBUG(1, ("Failed to add ARCFOUR_HMAC (only) entry for %s to keytab: %s",
 422                                   cli_credentials_get_principal(machine_account, mem_ctx),
 423                                   smb_get_krb5_error_message(smb_krb5_context->krb5_context,
 424                                                              ret, mem_ctx)));
 425                         talloc_free(mem_ctx);
 426                         krb5_free_keyblock_contents(smb_krb5_context->krb5_context, &entry.keyblock);
 427                         return ret;
 428                 }
 429
 430                 krb5_enctype_to_string(smb_krb5_context->krb5_context, ENCTYPE_ARCFOUR_HMAC, &enctype_string);
 431                 DEBUG(5, ("Added %s(kvno %d) to keytab (%s)\n",
 432                           cli_credentials_get_principal(machine_account, mem_ctx),
 433                           cli_credentials_get_kvno(machine_account),
 434                           enctype_string));
 435                 free(enctype_string);
 436
 437                 krb5_free_keyblock_contents(smb_krb5_context->krb5_context, &entry.keyblock);
 438
 439                 /* Can't go any further, we only have this one key */
 440                 talloc_free(mem_ctx);
 441                 return 0;
 442         }
 443
 444         kvno = cli_credentials_get_kvno(machine_account);
 445         /* good, we actually have the real plaintext */
 446         ret = keytab_add_keys(mem_ctx, princ_string, princ, salt_princ,
 447                               kvno, password_s, smb_krb5_context, keytab);
 448         if (!ret) {
 449                 talloc_free(mem_ctx);
 450                 return ret;
 451         }
 452
 453         if (!add_old || kvno == 0) {
 454                 talloc_free(mem_ctx);
 455                 return 0;
 456         }
 457
 458         old_secret = cli_credentials_get_old_password(machine_account);
 459         if (!old_secret) {
 460                 talloc_free(mem_ctx);
 461                 return 0;
 462         }
 463
 464         ret = keytab_add_keys(mem_ctx, princ_string, princ, salt_princ,
 465                               kvno - 1, old_secret, smb_krb5_context, 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                            struct keytab_container *keytab_container)
 610 {
 611         krb5_error_code ret;
 612         BOOL found_previous;
 613         TALLOC_CTX *mem_ctx = talloc_new(parent_ctx);
 614         if (!mem_ctx) {
 615                 return ENOMEM;
 616         }
 617
 618         ret = remove_old_entries(mem_ctx, machine_account,
 619                                  smb_krb5_context, keytab_container->keytab, &found_previous);
 620         if (ret != 0) {
 621                 talloc_free(mem_ctx);
 622                 return ret;
 623         }
 624
 625         /* Create a new keytab.  If during the cleanout we found
 626          * entires for kvno -1, then don't try and duplicate them.
 627          * Otherwise, add kvno, and kvno -1 */
 628
 629         ret = create_keytab(mem_ctx, machine_account, smb_krb5_context,
 630                             keytab_container->keytab,
 631                             found_previous ? False : True);
 632         talloc_free(mem_ctx);
 633         return ret;
 634 }
 635
 636 int smb_krb5_create_memory_keytab(TALLOC_CTX *parent_ctx,
 637                                   struct cli_credentials *machine_account,
 638                                   struct smb_krb5_context *smb_krb5_context,
 639                                   struct keytab_container **keytab_container)
 640 {
 641         krb5_error_code ret;
 642         TALLOC_CTX *mem_ctx = talloc_new(parent_ctx);
 643         const char *rand_string;
 644         const char *keytab_name;
 645         if (!mem_ctx) {
 646                 return ENOMEM;
 647         }
 648
 649         *keytab_container = talloc(mem_ctx, struct keytab_container);
 650
 651         rand_string = generate_random_str(mem_ctx, 16);
 652         if (!rand_string) {
 653                 talloc_free(mem_ctx);
 654                 return ENOMEM;
 655         }
 656
 657         keytab_name = talloc_asprintf(mem_ctx, "MEMORY:%s",
 658                                       rand_string);
 659         if (!keytab_name) {
 660                 talloc_free(mem_ctx);
 661                 return ENOMEM;
 662         }
 663
 664         ret = smb_krb5_open_keytab(mem_ctx, smb_krb5_context, keytab_name, keytab_container);
 665         if (ret) {
 666                 return ret;
 667         }
 668
 669         ret = smb_krb5_update_keytab(mem_ctx, machine_account, smb_krb5_context, *keytab_container);
 670         if (ret == 0) {
 671                 talloc_steal(parent_ctx, *keytab_container);
 672         } else {
 673                 *keytab_container = NULL;
 674         }
 675         talloc_free(mem_ctx);
 676         return ret;
 677 }
 678