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 "system/time.h"
  27 #include "system/network.h"
  28 #include "auth/kerberos/kerberos.h"
  29 #include "auth/auth.h"
  30
  31 struct principal_container {
  32         struct smb_krb5_context *smb_krb5_context;
  33         krb5_principal principal;
  34 };
  35
  36 static int free_principal(void *ptr) {
  37         struct principal_container *pc = ptr;
  38         /* current heimdal - 0.6.3, which we need anyway, fixes segfaults here */
  39         krb5_free_principal(pc->smb_krb5_context->krb5_context, pc->principal);
  40
  41         return 0;
  42 }
  43
  44 krb5_error_code salt_principal_from_credentials(TALLOC_CTX *parent_ctx,
  45                                                 struct cli_credentials *machine_account,
  46                                                 struct smb_krb5_context *smb_krb5_context,
  47                                                 krb5_principal *salt_princ)
  48 {
  49         krb5_error_code ret;
  50         char *machine_username;
  51         char *salt_body;
  52         char *lower_realm;
  53         const char *salt_principal;
  54         struct principal_container *mem_ctx = talloc(parent_ctx, struct principal_container);
  55         if (!mem_ctx) {
  56                 return ENOMEM;
  57         }
  58
  59         salt_principal = cli_credentials_get_salt_principal(machine_account);
  60         if (salt_principal) {
  61                 ret = krb5_parse_name(smb_krb5_context->krb5_context, salt_principal, salt_princ);
  62         } else {
  63                 machine_username = talloc_strdup(mem_ctx, cli_credentials_get_username(machine_account));
  64
  65                 if (!machine_username) {
  66                         talloc_free(mem_ctx);
  67                         return ENOMEM;
  68                 }
  69
  70                 if (machine_username[strlen(machine_username)-1] == '$') {
  71                         machine_username[strlen(machine_username)-1] = '\0';
  72                 }
  73                 lower_realm = strlower_talloc(mem_ctx, cli_credentials_get_realm(machine_account));
  74                 if (!lower_realm) {
  75                         talloc_free(mem_ctx);
  76                         return ENOMEM;
  77                 }
  78
  79                 salt_body = talloc_asprintf(mem_ctx, "%s.%s", machine_username,
  80                                             lower_realm);
  81                 if (!salt_body) {
  82                         talloc_free(mem_ctx);
  83                 return ENOMEM;
  84                 }
  85
  86                 ret = krb5_make_principal(smb_krb5_context->krb5_context, salt_princ,
  87                                           cli_credentials_get_realm(machine_account),
  88                                           "host", salt_body, NULL);
  89         }
  90
  91         if (ret == 0) {
  92                 /* This song-and-dance effectivly puts the principal
  93                  * into talloc, so we can't loose it. */
  94                 mem_ctx->smb_krb5_context = talloc_reference(mem_ctx, smb_krb5_context);
  95                 mem_ctx->principal = *salt_princ;
  96                 talloc_set_destructor(mem_ctx, free_principal);
  97         }
  98         return ret;
  99 }
 100
 101 /* Obtain the principal set on this context.  Requires a
 102  * smb_krb5_context because we are doing krb5 principal parsing with
 103  * the library routines.  The returned princ is placed in the talloc
 104  * system by means of a destructor (do *not* free). */
 105
 106 krb5_error_code principal_from_credentials(TALLOC_CTX *parent_ctx,
 107                                            struct cli_credentials *credentials,
 108                                            struct smb_krb5_context *smb_krb5_context,
 109                                            krb5_principal *princ)
 110 {
 111         krb5_error_code ret;
 112         const char *princ_string;
 113         struct principal_container *mem_ctx = talloc(parent_ctx, struct principal_container);
 114         if (!mem_ctx) {
 115                 return ENOMEM;
 116         }
 117
 118         princ_string = cli_credentials_get_principal(credentials, mem_ctx);
 119
 120         /* A NULL here has meaning, as the gssapi server case will
 121          * then use the principal from the client */
 122         if (!princ_string) {
 123                 talloc_free(mem_ctx);
 124                 princ = NULL;
 125                 return 0;
 126         }
 127
 128         ret = krb5_parse_name(smb_krb5_context->krb5_context,
 129                               princ_string, princ);
 130
 131         if (ret == 0) {
 132                 /* This song-and-dance effectivly puts the principal
 133                  * into talloc, so we can't loose it. */
 134                 mem_ctx->smb_krb5_context = talloc_reference(mem_ctx, smb_krb5_context);
 135                 mem_ctx->principal = *princ;
 136                 talloc_set_destructor(mem_ctx, free_principal);
 137         }
 138         return ret;
 139 }
 140
 141 /**
 142  * Return a freshly allocated ccache (destroyed by destructor on child
 143  * of parent_ctx), for a given set of client credentials
 144  */
 145
 146  krb5_error_code kinit_to_ccache(TALLOC_CTX *parent_ctx,
 147                                  struct cli_credentials *credentials,
 148                                  struct smb_krb5_context *smb_krb5_context,
 149                                  krb5_ccache ccache)
 150 {
 151         krb5_error_code ret;
 152         const char *password;
 153         time_t kdc_time = 0;
 154         krb5_principal princ;
 155
 156         TALLOC_CTX *mem_ctx = talloc_new(parent_ctx);
 157
 158         if (!mem_ctx) {
 159                 return ENOMEM;
 160         }
 161
 162         ret = principal_from_credentials(mem_ctx, credentials, smb_krb5_context, &princ);
 163         if (ret) {
 164                 talloc_free(mem_ctx);
 165                 return ret;
 166         }
 167
 168         password = cli_credentials_get_password(credentials);
 169
 170         if (password) {
 171                 ret = kerberos_kinit_password_cc(smb_krb5_context->krb5_context, ccache,
 172                                                  princ,
 173                                                  password, NULL, &kdc_time);
 174         } else {
 175                 /* No password available, try to use a keyblock instead */
 176
 177                 krb5_keyblock keyblock;
 178                 const struct samr_Password *mach_pwd;
 179                 mach_pwd = cli_credentials_get_nt_hash(credentials, mem_ctx);
 180                 if (!mach_pwd) {
 181                         talloc_free(mem_ctx);
 182                         DEBUG(1, ("kinit_to_ccache: No password available for kinit\n"));
 183                         return EINVAL;
 184                 }
 185                 ret = krb5_keyblock_init(smb_krb5_context->krb5_context,
 186                                          ENCTYPE_ARCFOUR_HMAC,
 187                                          mach_pwd->hash, sizeof(mach_pwd->hash),
 188                                          &keyblock);
 189
 190                 if (ret == 0) {
 191                         ret = kerberos_kinit_keyblock_cc(smb_krb5_context->krb5_context, ccache,
 192                                                          princ,
 193                                                          &keyblock, NULL, &kdc_time);
 194                         krb5_free_keyblock_contents(smb_krb5_context->krb5_context, &keyblock);
 195                 }
 196         }
 197
 198         /* cope with ticket being in the future due to clock skew */
 199         if ((unsigned)kdc_time > time(NULL)) {
 200                 time_t t = time(NULL);
 201                 int time_offset =(unsigned)kdc_time-t;
 202                 DEBUG(4,("Advancing clock by %d seconds to cope with clock skew\n", time_offset));
 203                 krb5_set_real_time(smb_krb5_context->krb5_context, t + time_offset + 1, 0);
 204         }
 205
 206         if (ret == KRB5KRB_AP_ERR_SKEW || ret == KRB5_KDCREP_SKEW) {
 207                 DEBUG(1,("kinit for %s failed (%s)\n",
 208                          cli_credentials_get_principal(credentials, mem_ctx),
 209                          smb_get_krb5_error_message(smb_krb5_context->krb5_context,
 210                                                     ret, mem_ctx)));
 211                 talloc_free(mem_ctx);
 212                 return ret;
 213         }
 214         if (ret) {
 215                 DEBUG(1,("kinit for %s failed (%s)\n",
 216                          cli_credentials_get_principal(credentials, mem_ctx),
 217                          smb_get_krb5_error_message(smb_krb5_context->krb5_context,
 218                                                     ret, mem_ctx)));
 219                 talloc_free(mem_ctx);
 220                 return ret;
 221         }
 222         return 0;
 223 }
 224
 225 static int free_keytab(void *ptr) {
 226         struct keytab_container *ktc = ptr;
 227         krb5_kt_close(ktc->smb_krb5_context->krb5_context, ktc->keytab);
 228
 229         return 0;
 230 }
 231
 232 int smb_krb5_open_keytab(TALLOC_CTX *mem_ctx,
 233                          struct smb_krb5_context *smb_krb5_context,
 234                          const char *keytab_name, struct keytab_container **ktc)
 235 {
 236         krb5_keytab keytab;
 237         int ret;
 238         ret = krb5_kt_resolve(smb_krb5_context->krb5_context, keytab_name, &keytab);
 239         if (ret) {
 240                 DEBUG(1,("failed to open krb5 keytab: %s\n",
 241                          smb_get_krb5_error_message(smb_krb5_context->krb5_context,
 242                                                     ret, mem_ctx)));
 243                 return ret;
 244         }
 245
 246         *ktc = talloc(mem_ctx, struct keytab_container);
 247         if (!*ktc) {
 248                 return ENOMEM;
 249         }
 250
 251         (*ktc)->smb_krb5_context = talloc_reference(*ktc, smb_krb5_context);
 252         (*ktc)->keytab = keytab;
 253         talloc_set_destructor(*ktc, free_keytab);
 254
 255         return 0;
 256 }
 257
 258 struct enctypes_container {
 259         struct smb_krb5_context *smb_krb5_context;
 260         krb5_enctype *enctypes;
 261 };
 262
 263 static int free_enctypes(void *ptr) {
 264         struct enctypes_container *etc = ptr;
 265         free_kerberos_etypes(etc->smb_krb5_context->krb5_context, etc->enctypes);
 266         return 0;
 267 }
 268
 269 static krb5_error_code keytab_add_keys(TALLOC_CTX *parent_ctx,
 270                                        const char *princ_string,
 271                                        krb5_principal princ,
 272                                        krb5_principal salt_princ,
 273                                        int kvno,
 274                                        const char *password_s,
 275                                        struct smb_krb5_context *smb_krb5_context,
 276                                        krb5_keytab keytab)
 277 {
 278         int i;
 279         krb5_error_code ret;
 280         krb5_enctype *enctypes;
 281         char *enctype_string;
 282         struct enctypes_container *etc;
 283         krb5_data password;
 284         TALLOC_CTX *mem_ctx = talloc_new(parent_ctx);
 285         if (!mem_ctx) {
 286                 return ENOMEM;
 287         }
 288
 289         etc = talloc(mem_ctx, struct enctypes_container);
 290         if (!etc) {
 291                 talloc_free(mem_ctx);
 292                 return ENOMEM;
 293         }
 294         ret = get_kerberos_allowed_etypes(smb_krb5_context->krb5_context,
 295                                           &enctypes);
 296         if (ret != 0) {
 297                 DEBUG(1,("keytab_add_keys: getting encrption types failed (%s)\n",
 298                          error_message(ret)));
 299                 talloc_free(mem_ctx);
 300                 return ret;
 301         }
 302
 303         etc->smb_krb5_context = talloc_reference(etc, smb_krb5_context);
 304         etc->enctypes = enctypes;
 305
 306         talloc_set_destructor(etc, free_enctypes);
 307
 308         password.data = discard_const_p(char *, password_s);
 309         password.length = strlen(password_s);
 310
 311         for (i=0; enctypes[i]; i++) {
 312                 krb5_keytab_entry entry;
 313                 ret = create_kerberos_key_from_string(smb_krb5_context->krb5_context,
 314                                                       salt_princ, &password, &entry.keyblock, enctypes[i]);
 315                 if (ret != 0) {
 316                         talloc_free(mem_ctx);
 317                         return ret;
 318                 }
 319
 320                 entry.principal = princ;
 321                 entry.vno       = kvno;
 322                 ret = krb5_kt_add_entry(smb_krb5_context->krb5_context, keytab, &entry);
 323                 enctype_string = NULL;
 324                 krb5_enctype_to_string(smb_krb5_context->krb5_context, enctypes[i], &enctype_string);
 325                 if (ret != 0) {
 326                         DEBUG(1, ("Failed to add %s entry for %s(kvno %d) to keytab: %s\n",
 327                                   enctype_string,
 328                                   princ_string,
 329                                   kvno,
 330                                   smb_get_krb5_error_message(smb_krb5_context->krb5_context,
 331                                                              ret, mem_ctx)));
 332                         talloc_free(mem_ctx);
 333                         free(enctype_string);
 334                         krb5_free_keyblock_contents(smb_krb5_context->krb5_context, &entry.keyblock);
 335                         return ret;
 336                 }
 337
 338                 DEBUG(5, ("Added %s(kvno %d) to keytab (%s)\n",
 339                           princ_string, kvno,
 340                           enctype_string));
 341                 free(enctype_string);
 342
 343                 krb5_free_keyblock_contents(smb_krb5_context->krb5_context, &entry.keyblock);
 344         }
 345         talloc_free(mem_ctx);
 346         return 0;
 347 }
 348
 349 static int create_keytab(TALLOC_CTX *parent_ctx,
 350                          struct cli_credentials *machine_account,
 351                          struct smb_krb5_context *smb_krb5_context,
 352                          krb5_keytab keytab,
 353                          BOOL add_old)
 354 {
 355         krb5_error_code ret;
 356         const char *password_s;
 357         char *enctype_string;
 358         const char *old_secret;
 359         int kvno;
 360         krb5_principal salt_princ;
 361         krb5_principal princ;
 362         const char *princ_string;
 363
 364         TALLOC_CTX *mem_ctx = talloc_new(parent_ctx);
 365         if (!mem_ctx) {
 366                 return ENOMEM;
 367         }
 368
 369         princ_string = cli_credentials_get_principal(machine_account, mem_ctx);
 370         /* Get the principal we will store the new keytab entries under */
 371         ret = principal_from_credentials(mem_ctx, machine_account, smb_krb5_context, &princ);
 372         if (ret) {
 373                 DEBUG(1,("create_keytab: makeing krb5 principal failed (%s)\n",
 374                          smb_get_krb5_error_message(smb_krb5_context->krb5_context,
 375                                                     ret, mem_ctx)));
 376                 talloc_free(mem_ctx);
 377                 return ret;
 378         }
 379
 380         /* The salt used to generate these entries may be different however, fetch that */
 381         ret = salt_principal_from_credentials(mem_ctx, machine_account,
 382                                               smb_krb5_context,
 383                                               &salt_princ);
 384         if (ret) {
 385                 DEBUG(1,("create_keytab: makeing salt principal failed (%s)\n",
 386                          smb_get_krb5_error_message(smb_krb5_context->krb5_context,
 387                                                     ret, mem_ctx)));
 388                 talloc_free(mem_ctx);
 389                 return ret;
 390         }
 391
 392         /* Finally, do the dance to get the password to put in the entry */
 393         password_s = cli_credentials_get_password(machine_account);
 394         if (!password_s) {
 395                 /* If we don't have the plaintext password, try for
 396                  * the MD4 password hash */
 397
 398                 krb5_keytab_entry entry;
 399                 const struct samr_Password *mach_pwd;
 400                 mach_pwd = cli_credentials_get_nt_hash(machine_account, mem_ctx);
 401                 if (!mach_pwd) {
 402                         talloc_free(mem_ctx);
 403                         DEBUG(1, ("create_keytab: Domain trust informaton for account %s not available\n",
 404                                   cli_credentials_get_principal(machine_account, mem_ctx)));
 405                         return EINVAL;
 406                 }
 407                 ret = krb5_keyblock_init(smb_krb5_context->krb5_context,
 408                                          ENCTYPE_ARCFOUR_HMAC,
 409                                          mach_pwd->hash, sizeof(mach_pwd->hash),
 410                                          &entry.keyblock);
 411                 if (ret) {
 412                         DEBUG(1, ("create_keytab: krb5_keyblock_init failed: %s\n",
 413                                   smb_get_krb5_error_message(smb_krb5_context->krb5_context,
 414                                                              ret, 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                 krb5_enctype_to_string(smb_krb5_context->krb5_context, ENCTYPE_ARCFOUR_HMAC, &enctype_string);
 432                 DEBUG(5, ("Added %s(kvno %d) to keytab (%s)\n",
 433                           cli_credentials_get_principal(machine_account, mem_ctx),
 434                           cli_credentials_get_kvno(machine_account),
 435                           enctype_string));
 436                 free(enctype_string);
 437
 438                 krb5_free_keyblock_contents(smb_krb5_context->krb5_context, &entry.keyblock);
 439
 440                 /* Can't go any further, we only have this one key */
 441                 talloc_free(mem_ctx);
 442                 return 0;
 443         }
 444
 445         kvno = cli_credentials_get_kvno(machine_account);
 446         /* good, we actually have the real plaintext */
 447         ret = keytab_add_keys(mem_ctx, princ_string, princ, salt_princ,
 448                               kvno, password_s, smb_krb5_context, keytab);
 449         if (!ret) {
 450                 talloc_free(mem_ctx);
 451                 return ret;
 452         }
 453
 454         if (!add_old || kvno == 0) {
 455                 talloc_free(mem_ctx);
 456                 return 0;
 457         }
 458
 459         old_secret = cli_credentials_get_old_password(machine_account);
 460         if (!old_secret) {
 461                 talloc_free(mem_ctx);
 462                 return 0;
 463         }
 464
 465         ret = keytab_add_keys(mem_ctx, princ_string, princ, salt_princ,
 466                               kvno - 1, old_secret, smb_krb5_context, keytab);
 467         if (!ret) {
 468                 talloc_free(mem_ctx);
 469                 return ret;
 470         }
 471
 472         talloc_free(mem_ctx);
 473         return 0;
 474 }
 475
 476
 477 /*
 478  * Walk the keytab, looking for entries of this principal name, with KVNO other than current kvno -1.
 479  *
 480  * These entries are now stale, we only keep the current, and previous entries around.
 481  *
 482  * Inspired by the code in Samba3 for 'use kerberos keytab'.
 483  *
 484  */
 485
 486 static krb5_error_code remove_old_entries(TALLOC_CTX *parent_ctx,
 487                                           struct cli_credentials *machine_account,
 488                                           struct smb_krb5_context *smb_krb5_context,
 489                                           krb5_keytab keytab, BOOL *found_previous)
 490 {
 491         krb5_error_code ret, ret2;
 492         krb5_kt_cursor cursor;
 493         krb5_principal princ;
 494         int kvno;
 495         TALLOC_CTX *mem_ctx = talloc_new(parent_ctx);
 496         const char *princ_string;
 497         if (!mem_ctx) {
 498                 return ENOMEM;
 499         }
 500
 501         *found_previous = False;
 502         princ_string = cli_credentials_get_principal(machine_account, mem_ctx);
 503
 504         /* Get the principal we will store the new keytab entries under */
 505         ret = principal_from_credentials(mem_ctx, machine_account, smb_krb5_context, &princ);
 506         if (ret) {
 507                 DEBUG(1,("update_keytab: makeing krb5 principal failed (%s)\n",
 508                          smb_get_krb5_error_message(smb_krb5_context->krb5_context,
 509                                                     ret, mem_ctx)));
 510                 talloc_free(mem_ctx);
 511                 return ret;
 512         }
 513
 514         kvno = cli_credentials_get_kvno(machine_account);
 515
 516         /* for each entry in the keytab */
 517         ret = krb5_kt_start_seq_get(smb_krb5_context->krb5_context, keytab, &cursor);
 518         switch (ret) {
 519         case 0:
 520                 break;
 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