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(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 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                                          ETYPE_ARCFOUR_HMAC_MD5,
 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
 213         if (ret == KRB5KDC_ERR_PREAUTH_FAILED && cli_credentials_wrong_password(credentials)) {
 214                 ret = kinit_to_ccache(parent_ctx,
 215                                       credentials,
 216                                       smb_krb5_context,
 217                                       ccache);
 218         }
 219         if (ret) {
 220                 DEBUG(1,("kinit for %s failed (%s)\n",
 221                          cli_credentials_get_principal(credentials, mem_ctx),
 222                          smb_get_krb5_error_message(smb_krb5_context->krb5_context,
 223                                                     ret, mem_ctx)));
 224                 talloc_free(mem_ctx);
 225                 return ret;
 226         }
 227         return 0;
 228 }
 229
 230 static int free_keytab(struct keytab_container *ktc)
 231 {
 232         krb5_kt_close(ktc->smb_krb5_context->krb5_context, ktc->keytab);
 233
 234         return 0;
 235 }
 236
 237 int smb_krb5_open_keytab(TALLOC_CTX *mem_ctx,
 238                          struct smb_krb5_context *smb_krb5_context,
 239                          const char *keytab_name, struct keytab_container **ktc)
 240 {
 241         krb5_keytab keytab;
 242         int ret;
 243         ret = krb5_kt_resolve(smb_krb5_context->krb5_context, keytab_name, &keytab);
 244         if (ret) {
 245                 DEBUG(1,("failed to open krb5 keytab: %s\n",
 246                          smb_get_krb5_error_message(smb_krb5_context->krb5_context,
 247                                                     ret, mem_ctx)));
 248                 return ret;
 249         }
 250
 251         *ktc = talloc(mem_ctx, struct keytab_container);
 252         if (!*ktc) {
 253                 return ENOMEM;
 254         }
 255
 256         (*ktc)->smb_krb5_context = talloc_reference(*ktc, smb_krb5_context);
 257         (*ktc)->keytab = keytab;
 258         talloc_set_destructor(*ktc, free_keytab);
 259
 260         return 0;
 261 }
 262
 263 struct enctypes_container {
 264         struct smb_krb5_context *smb_krb5_context;
 265         krb5_enctype *enctypes;
 266 };
 267
 268 static int free_enctypes(struct enctypes_container *etc)
 269 {
 270         free_kerberos_etypes(etc->smb_krb5_context->krb5_context, etc->enctypes);
 271         return 0;
 272 }
 273
 274 static krb5_error_code keytab_add_keys(TALLOC_CTX *parent_ctx,
 275                                        const char *princ_string,
 276                                        krb5_principal princ,
 277                                        krb5_principal salt_princ,
 278                                        int kvno,
 279                                        const char *password_s,
 280                                        struct smb_krb5_context *smb_krb5_context,
 281                                        krb5_keytab keytab)
 282 {
 283         int i;
 284         krb5_error_code ret;
 285         krb5_enctype *enctypes;
 286         char *enctype_string;
 287         struct enctypes_container *etc;
 288         krb5_data password;
 289         TALLOC_CTX *mem_ctx = talloc_new(parent_ctx);
 290         if (!mem_ctx) {
 291                 return ENOMEM;
 292         }
 293
 294         etc = talloc(mem_ctx, struct enctypes_container);
 295         if (!etc) {
 296                 talloc_free(mem_ctx);
 297                 return ENOMEM;
 298         }
 299         ret = get_kerberos_allowed_etypes(smb_krb5_context->krb5_context,
 300                                           &enctypes);
 301         if (ret != 0) {
 302                 DEBUG(1,("keytab_add_keys: getting encrption types failed (%s)\n",
 303                          error_message(ret)));
 304                 talloc_free(mem_ctx);
 305                 return ret;
 306         }
 307
 308         etc->smb_krb5_context = talloc_reference(etc, smb_krb5_context);
 309         etc->enctypes = enctypes;
 310
 311         talloc_set_destructor(etc, free_enctypes);
 312
 313         password.data = discard_const_p(char *, password_s);
 314         password.length = strlen(password_s);
 315
 316         for (i=0; enctypes[i]; i++) {
 317                 krb5_keytab_entry entry;
 318                 ret = create_kerberos_key_from_string(smb_krb5_context->krb5_context,
 319                                                       salt_princ, &password, &entry.keyblock, enctypes[i]);
 320                 if (ret != 0) {
 321                         talloc_free(mem_ctx);
 322                         return ret;
 323                 }
 324
 325                 entry.principal = princ;
 326                 entry.vno       = kvno;
 327                 ret = krb5_kt_add_entry(smb_krb5_context->krb5_context, keytab, &entry);
 328                 enctype_string = NULL;
 329                 krb5_enctype_to_string(smb_krb5_context->krb5_context, enctypes[i], &enctype_string);
 330                 if (ret != 0) {
 331                         DEBUG(1, ("Failed to add %s entry for %s(kvno %d) to keytab: %s\n",
 332                                   enctype_string,
 333                                   princ_string,
 334                                   kvno,
 335                                   smb_get_krb5_error_message(smb_krb5_context->krb5_context,
 336                                                              ret, mem_ctx)));
 337                         talloc_free(mem_ctx);
 338                         free(enctype_string);
 339                         krb5_free_keyblock_contents(smb_krb5_context->krb5_context, &entry.keyblock);
 340                         return ret;
 341                 }
 342
 343                 DEBUG(5, ("Added %s(kvno %d) to keytab (%s)\n",
 344                           princ_string, kvno,
 345                           enctype_string));
 346                 free(enctype_string);
 347
 348                 krb5_free_keyblock_contents(smb_krb5_context->krb5_context, &entry.keyblock);
 349         }
 350         talloc_free(mem_ctx);
 351         return 0;
 352 }
 353
 354 static int create_keytab(TALLOC_CTX *parent_ctx,
 355                          struct cli_credentials *machine_account,
 356                          struct smb_krb5_context *smb_krb5_context,
 357                          krb5_keytab keytab,
 358                          BOOL add_old)
 359 {
 360         krb5_error_code ret;
 361         const char *password_s;
 362         char *enctype_string;
 363         const char *old_secret;
 364         int kvno;
 365         krb5_principal salt_princ;
 366         krb5_principal princ;
 367         const char *princ_string;
 368
 369         TALLOC_CTX *mem_ctx = talloc_new(parent_ctx);
 370         if (!mem_ctx) {
 371                 return ENOMEM;
 372         }
 373
 374         princ_string = cli_credentials_get_principal(machine_account, mem_ctx);
 375         /* Get the principal we will store the new keytab entries under */
 376         ret = principal_from_credentials(mem_ctx, machine_account, smb_krb5_context, &princ);
 377         if (ret) {
 378                 DEBUG(1,("create_keytab: makeing krb5 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         /* The salt used to generate these entries may be different however, fetch that */
 386         ret = salt_principal_from_credentials(mem_ctx, machine_account,
 387                                               smb_krb5_context,
 388                                               &salt_princ);
 389         if (ret) {
 390                 DEBUG(1,("create_keytab: makeing salt 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         /* Finally, do the dance to get the password to put in the entry */
 398         password_s = cli_credentials_get_password(machine_account);
 399         if (!password_s) {
 400                 /* If we don't have the plaintext password, try for
 401                  * the MD4 password hash */
 402
 403                 krb5_keytab_entry entry;
 404                 const struct samr_Password *mach_pwd;
 405                 mach_pwd = cli_credentials_get_nt_hash(machine_account, mem_ctx);
 406                 if (!mach_pwd) {
 407                         DEBUG(1, ("create_keytab: Domain trust informaton for account %s not available\n",
 408                                   cli_credentials_get_principal(machine_account, mem_ctx)));
 409                         talloc_free(mem_ctx);
 410                         return EINVAL;
 411                 }
 412                 ret = krb5_keyblock_init(smb_krb5_context->krb5_context,
 413                                          ETYPE_ARCFOUR_HMAC_MD5,
 414                                          mach_pwd->hash, sizeof(mach_pwd->hash),
 415                                          &entry.keyblock);
 416                 if (ret) {
 417                         DEBUG(1, ("create_keytab: krb5_keyblock_init failed: %s\n",
 418                                   smb_get_krb5_error_message(smb_krb5_context->krb5_context,
 419                                                              ret, mem_ctx)));
 420                         talloc_free(mem_ctx);
 421                         return ret;
 422                 }
 423
 424                 entry.principal = princ;
 425                 entry.vno       = cli_credentials_get_kvno(machine_account);
 426                 ret = krb5_kt_add_entry(smb_krb5_context->krb5_context, keytab, &entry);
 427                 if (ret) {
 428                         DEBUG(1, ("Failed to add ARCFOUR_HMAC (only) entry for %s to keytab: %s",
 429                                   cli_credentials_get_principal(machine_account, mem_ctx),
 430                                   smb_get_krb5_error_message(smb_krb5_context->krb5_context,
 431                                                              ret, mem_ctx)));
 432                         talloc_free(mem_ctx);
 433                         krb5_free_keyblock_contents(smb_krb5_context->krb5_context, &entry.keyblock);
 434                         return ret;
 435                 }
 436
 437                 krb5_enctype_to_string(smb_krb5_context->krb5_context,
 438                                        ETYPE_ARCFOUR_HMAC_MD5,
 439                                        &enctype_string);
 440                 DEBUG(5, ("Added %s(kvno %d) to keytab (%s)\n",
 441                           cli_credentials_get_principal(machine_account, mem_ctx),
 442                           cli_credentials_get_kvno(machine_account),
 443                           enctype_string));
 444                 free(enctype_string);
 445
 446                 krb5_free_keyblock_contents(smb_krb5_context->krb5_context, &entry.keyblock);
 447
 448                 /* Can't go any further, we only have this one key */
 449                 talloc_free(mem_ctx);
 450                 return 0;
 451         }
 452
 453         kvno = cli_credentials_get_kvno(machine_account);
 454         /* good, we actually have the real plaintext */
 455         ret = keytab_add_keys(mem_ctx, princ_string, princ, salt_princ,
 456                               kvno, password_s, smb_krb5_context, keytab);
 457         if (!ret) {
 458                 talloc_free(mem_ctx);
 459                 return ret;
 460         }
 461
 462         if (!add_old || kvno == 0) {
 463                 talloc_free(mem_ctx);
 464                 return 0;
 465         }
 466
 467         old_secret = cli_credentials_get_old_password(machine_account);
 468         if (!old_secret) {
 469                 talloc_free(mem_ctx);
 470                 return 0;
 471         }
 472
 473         ret = keytab_add_keys(mem_ctx, princ_string, princ, salt_princ,
 474                               kvno - 1, old_secret, smb_krb5_context, keytab);
 475         if (!ret) {
 476                 talloc_free(mem_ctx);
 477                 return ret;
 478         }
 479
 480         talloc_free(mem_ctx);
 481         return 0;
 482 }
 483
 484
 485 /*
 486  * Walk the keytab, looking for entries of this principal name, with KVNO other than current kvno -1.
 487  *
 488  * These entries are now stale, we only keep the current, and previous entries around.
 489  *
 490  * Inspired by the code in Samba3 for 'use kerberos keytab'.
 491  *
 492  */
 493
 494 static krb5_error_code remove_old_entries(TALLOC_CTX *parent_ctx,
 495                                           struct cli_credentials *machine_account,
 496                                           struct smb_krb5_context *smb_krb5_context,
 497                                           krb5_keytab keytab, BOOL *found_previous)
 498 {
 499         krb5_error_code ret, ret2;
 500         krb5_kt_cursor cursor;
 501         krb5_principal princ;
 502         int kvno;
 503         TALLOC_CTX *mem_ctx = talloc_new(parent_ctx);
 504         const char *princ_string;
 505         if (!mem_ctx) {
 506                 return ENOMEM;
 507         }
 508
 509         *found_previous = False;
 510         princ_string = cli_credentials_get_principal(machine_account, mem_ctx);
 511
 512         /* Get the principal we will store the new keytab entries under */
 513         ret = principal_from_credentials(mem_ctx, machine_account, smb_krb5_context, &princ);
 514         if (ret) {
 515                 DEBUG(1,("update_keytab: makeing krb5 principal failed (%s)\n",
 516                          smb_get_krb5_error_message(smb_krb5_context->krb5_context,
 517                                                     ret, mem_ctx)));
 518                 talloc_free(mem_ctx);
 519                 return ret;
 520         }
 521
 522         kvno = cli_credentials_get_kvno(machine_account);
 523
 524         /* for each entry in the keytab */
 525         ret = krb5_kt_start_seq_get(smb_krb5_context->krb5_context, keytab, &cursor);
 526         switch (ret) {
 527         case 0:
 528                 break;
 529         case HEIM_ERR_OPNOTSUPP:
 530         case ENOENT:
 531         case KRB5_KT_END:
 532                 /* no point enumerating if there isn't anything here */
 533                 talloc_free(mem_ctx);
 534                 return 0;
 535         default:
 536                 DEBUG(1,("failed to open keytab for read of old entries: %s\n",
 537                          smb_get_krb5_error_message(smb_krb5_context->krb5_context,
 538                                                     ret, mem_ctx)));
 539                 talloc_free(mem_ctx);
 540                 return ret;
 541         }
 542
 543         while (!ret) {
 544                 krb5_keytab_entry entry;
 545                 ret = krb5_kt_next_entry(smb_krb5_context->krb5_context, keytab, &entry, &cursor);
 546                 if (ret) {
 547                         break;
 548                 }
 549                 /* if it matches our principal */
 550                 if (!krb5_kt_compare(smb_krb5_context->krb5_context, &entry, princ, 0, 0)) {
 551                         /* Free the entry, it wasn't the one we were looking for anyway */
 552                         krb5_kt_free_entry(smb_krb5_context->krb5_context, &entry);
 553                         continue;
 554                 }
 555
 556                 /* delete it, if it is not kvno -1 */
 557                 if (entry.vno != (kvno - 1 )) {
 558                         /* Release the enumeration.  We are going to
 559                          * have to start this from the top again,
 560                          * because deletes during enumeration may not
 561                          * always be consistant.
 562                          *
 563                          * Also, the enumeration locks a FILE: keytab
 564                          */
 565
 566                         krb5_kt_end_seq_get(smb_krb5_context->krb5_context, keytab, &cursor);
 567
 568                         ret = krb5_kt_remove_entry(smb_krb5_context->krb5_context, keytab, &entry);
 569                         krb5_kt_free_entry(smb_krb5_context->krb5_context, &entry);
 570
 571                         /* Deleted: Restart from the top */
 572                         ret2 = krb5_kt_start_seq_get(smb_krb5_context->krb5_context, keytab, &cursor);
 573                         if (ret2) {
 574                                 krb5_kt_free_entry(smb_krb5_context->krb5_context, &entry);
 575                                 DEBUG(1,("failed to restart enumeration of keytab: %s\n",
 576                                          smb_get_krb5_error_message(smb_krb5_context->krb5_context,
 577                                                                     ret, mem_ctx)));
 578
 579                                 talloc_free(mem_ctx);
 580                                 return ret2;
 581                         }
 582
 583                         if (ret) {
 584                                 break;
 585                         }
 586
 587                 } else {
 588                         *found_previous = True;
 589                 }
 590
 591                 /* Free the entry, we don't need it any more */
 592                 krb5_kt_free_entry(smb_krb5_context->krb5_context, &entry);
 593
 594
 595         }
 596         krb5_kt_end_seq_get(smb_krb5_context->krb5_context, keytab, &cursor);
 597
 598         switch (ret) {
 599         case 0:
 600                 break;
 601         case ENOENT:
 602         case KRB5_KT_END:
 603                 ret = 0;
 604                 break;
 605         default:
 606                 DEBUG(1,("failed in deleting old entries for principal: %s: %s\n",
 607                          princ_string,
 608                          smb_get_krb5_error_message(smb_krb5_context->krb5_context,
 609                                                     ret, mem_ctx)));
 610         }
 611         talloc_free(mem_ctx);
 612         return ret;
 613 }
 614
 615 int smb_krb5_update_keytab(TALLOC_CTX *parent_ctx,
 616                            struct cli_credentials *machine_account,
 617                            struct smb_krb5_context *smb_krb5_context,
 618                            struct keytab_container *keytab_container)
 619 {
 620         krb5_error_code ret;
 621         BOOL found_previous;
 622         TALLOC_CTX *mem_ctx = talloc_new(parent_ctx);
 623         if (!mem_ctx) {
 624                 return ENOMEM;
 625         }
 626
 627         ret = remove_old_entries(mem_ctx, machine_account,
 628                                  smb_krb5_context, keytab_container->keytab, &found_previous);
 629         if (ret != 0) {
 630                 talloc_free(mem_ctx);
 631                 return ret;
 632         }
 633
 634         /* Create a new keytab.  If during the cleanout we found
 635          * entires for kvno -1, then don't try and duplicate them.
 636          * Otherwise, add kvno, and kvno -1 */
 637
 638         ret = create_keytab(mem_ctx, machine_account, smb_krb5_context,
 639                             keytab_container->keytab,
 640                             found_previous ? False : True);
 641         talloc_free(mem_ctx);
 642         return ret;
 643 }
 644
 645 int smb_krb5_create_memory_keytab(TALLOC_CTX *parent_ctx,
 646                                   struct cli_credentials *machine_account,
 647                                   struct smb_krb5_context *smb_krb5_context,
 648                                   struct keytab_container **keytab_container)
 649 {
 650         krb5_error_code ret;
 651         TALLOC_CTX *mem_ctx = talloc_new(parent_ctx);
 652         const char *rand_string;
 653         const char *keytab_name;
 654         if (!mem_ctx) {
 655                 return ENOMEM;
 656         }
 657
 658         *keytab_container = talloc(mem_ctx, struct keytab_container);
 659
 660         rand_string = generate_random_str(mem_ctx, 16);
 661         if (!rand_string) {
 662                 talloc_free(mem_ctx);
 663                 return ENOMEM;
 664         }
 665
 666         keytab_name = talloc_asprintf(mem_ctx, "MEMORY:%s",
 667                                       rand_string);
 668         if (!keytab_name) {
 669                 talloc_free(mem_ctx);
 670                 return ENOMEM;
 671         }
 672
 673         ret = smb_krb5_open_keytab(mem_ctx, smb_krb5_context, keytab_name, keytab_container);
 674         if (ret) {
 675                 return ret;
 676         }
 677
 678         ret = smb_krb5_update_keytab(mem_ctx, machine_account, smb_krb5_context, *keytab_container);
 679         if (ret == 0) {
 680                 talloc_steal(parent_ctx, *keytab_container);
 681         } else {
 682                 *keytab_container = NULL;
 683         }
 684         talloc_free(mem_ctx);
 685         return ret;
 686 }
 687