source4/auth/kerberos/kerberos_util.c

   1 /*
   2    Unix SMB/CIFS implementation.
   3
   4    Kerberos utility functions for GENSEC
   5
   6    Copyright (C) Andrew Bartlett <abartlet@samba.org> 2004-2005
   7
   8    This program is free software; you can redistribute it and/or modify
   9    it under the terms of the GNU General Public License as published by
  10    the Free Software Foundation; either version 2 of the License, or
  11    (at your option) any later version.
  12
  13    This program is distributed in the hope that it will be useful,
  14    but WITHOUT ANY WARRANTY; without even the implied warranty of
  15    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16    GNU General Public License for more details.
  17
  18
  19    You should have received a copy of the GNU General Public License
  20    along with this program; if not, write to the Free Software
  21    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  22 */
  23
  24 #include "includes.h"
  25 #include "system/kerberos.h"
  26 #include "auth/kerberos/kerberos.h"
  27 #include "auth/credentials/credentials.h"
  28 #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         return 0;
 241 }
 242
 243 static int free_keytab(struct keytab_container *ktc)
 244 {
 245         krb5_kt_close(ktc->smb_krb5_context->krb5_context, ktc->keytab);
 246
 247         return 0;
 248 }
 249
 250 int smb_krb5_open_keytab(TALLOC_CTX *mem_ctx,
 251                          struct smb_krb5_context *smb_krb5_context,
 252                          const char *keytab_name, struct keytab_container **ktc)
 253 {
 254         krb5_keytab keytab;
 255         int ret;
 256         ret = krb5_kt_resolve(smb_krb5_context->krb5_context, keytab_name, &keytab);
 257         if (ret) {
 258                 DEBUG(1,("failed to open krb5 keytab: %s\n",
 259                          smb_get_krb5_error_message(smb_krb5_context->krb5_context,
 260                                                     ret, mem_ctx)));
 261                 return ret;
 262         }
 263
 264         *ktc = talloc(mem_ctx, struct keytab_container);
 265         if (!*ktc) {
 266                 return ENOMEM;
 267         }
 268
 269         (*ktc)->smb_krb5_context = talloc_reference(*ktc, smb_krb5_context);
 270         (*ktc)->keytab = keytab;
 271         talloc_set_destructor(*ktc, free_keytab);
 272
 273         return 0;
 274 }
 275
 276 struct enctypes_container {
 277         struct smb_krb5_context *smb_krb5_context;
 278         krb5_enctype *enctypes;
 279 };
 280
 281 static int free_enctypes(struct enctypes_container *etc)
 282 {
 283         free_kerberos_etypes(etc->smb_krb5_context->krb5_context, etc->enctypes);
 284         return 0;
 285 }
 286
 287 static krb5_error_code keytab_add_keys(TALLOC_CTX *parent_ctx,
 288                                        const char *princ_string,
 289                                        krb5_principal princ,
 290                                        krb5_principal salt_princ,
 291                                        int kvno,
 292                                        const char *password_s,
 293                                        struct smb_krb5_context *smb_krb5_context,
 294                                        krb5_keytab keytab)
 295 {
 296         int i;
 297         krb5_error_code ret;
 298         krb5_enctype *enctypes;
 299         char *enctype_string;
 300         struct enctypes_container *etc;
 301         krb5_data password;
 302         TALLOC_CTX *mem_ctx = talloc_new(parent_ctx);
 303         if (!mem_ctx) {
 304                 return ENOMEM;
 305         }
 306
 307         etc = talloc(mem_ctx, struct enctypes_container);
 308         if (!etc) {
 309                 talloc_free(mem_ctx);
 310                 return ENOMEM;
 311         }
 312         ret = get_kerberos_allowed_etypes(smb_krb5_context->krb5_context,
 313                                           &enctypes);
 314         if (ret != 0) {
 315                 DEBUG(1,("keytab_add_keys: getting encrption types failed (%s)\n",
 316                          error_message(ret)));
 317                 talloc_free(mem_ctx);
 318                 return ret;
 319         }
 320
 321         etc->smb_krb5_context = talloc_reference(etc, smb_krb5_context);
 322         etc->enctypes = enctypes;
 323
 324         talloc_set_destructor(etc, free_enctypes);
 325
 326         password.data = discard_const_p(char *, password_s);
 327         password.length = strlen(password_s);
 328
 329         for (i=0; enctypes[i]; i++) {
 330                 krb5_keytab_entry entry;
 331                 ret = create_kerberos_key_from_string(smb_krb5_context->krb5_context,
 332                                                       salt_princ, &password, &entry.keyblock, enctypes[i]);
 333                 if (ret != 0) {
 334                         talloc_free(mem_ctx);
 335                         return ret;
 336                 }
 337
 338                 entry.principal = princ;
 339                 entry.vno       = kvno;
 340                 ret = krb5_kt_add_entry(smb_krb5_context->krb5_context, keytab, &entry);
 341                 enctype_string = NULL;
 342                 krb5_enctype_to_string(smb_krb5_context->krb5_context, enctypes[i], &enctype_string);
 343                 if (ret != 0) {
 344                         DEBUG(1, ("Failed to add %s entry for %s(kvno %d) to keytab: %s\n",
 345                                   enctype_string,
 346                                   princ_string,
 347                                   kvno,
 348                                   smb_get_krb5_error_message(smb_krb5_context->krb5_context,
 349                                                              ret, mem_ctx)));
 350                         talloc_free(mem_ctx);
 351                         free(enctype_string);
 352                         krb5_free_keyblock_contents(smb_krb5_context->krb5_context, &entry.keyblock);
 353                         return ret;
 354                 }
 355
 356                 DEBUG(5, ("Added %s(kvno %d) to keytab (%s)\n",
 357                           princ_string, kvno,
 358                           enctype_string));
 359                 free(enctype_string);
 360
 361                 krb5_free_keyblock_contents(smb_krb5_context->krb5_context, &entry.keyblock);
 362         }
 363         talloc_free(mem_ctx);
 364         return 0;
 365 }
 366
 367 static int create_keytab(TALLOC_CTX *parent_ctx,
 368                          struct cli_credentials *machine_account,
 369                          struct smb_krb5_context *smb_krb5_context,
 370                          krb5_keytab keytab,
 371                          BOOL add_old)
 372 {
 373         krb5_error_code ret;
 374         const char *password_s;
 375         char *enctype_string;
 376         const char *old_secret;
 377         int kvno;
 378         krb5_principal salt_princ;
 379         krb5_principal princ;
 380         const char *princ_string;
 381
 382         TALLOC_CTX *mem_ctx = talloc_new(parent_ctx);
 383         if (!mem_ctx) {
 384                 return ENOMEM;
 385         }
 386
 387         princ_string = cli_credentials_get_principal(machine_account, mem_ctx);
 388         /* Get the principal we will store the new keytab entries under */
 389         ret = principal_from_credentials(mem_ctx, machine_account, smb_krb5_context, &princ);
 390         if (ret) {
 391                 DEBUG(1,("create_keytab: makeing krb5 principal failed (%s)\n",
 392                          smb_get_krb5_error_message(smb_krb5_context->krb5_context,
 393                                                     ret, mem_ctx)));
 394                 talloc_free(mem_ctx);
 395                 return ret;
 396         }
 397
 398         /* The salt used to generate these entries may be different however, fetch that */
 399         ret = salt_principal_from_credentials(mem_ctx, machine_account,
 400                                               smb_krb5_context,
 401                                               &salt_princ);
 402         if (ret) {
 403                 DEBUG(1,("create_keytab: makeing salt principal failed (%s)\n",
 404                          smb_get_krb5_error_message(smb_krb5_context->krb5_context,
 405                                                     ret, mem_ctx)));
 406                 talloc_free(mem_ctx);
 407                 return ret;
 408         }
 409
 410         /* Finally, do the dance to get the password to put in the entry */
 411         password_s = cli_credentials_get_password(machine_account);
 412         if (!password_s) {
 413                 /* If we don't have the plaintext password, try for
 414                  * the MD4 password hash */
 415
 416                 krb5_keytab_entry entry;
 417                 const struct samr_Password *mach_pwd;
 418                 mach_pwd = cli_credentials_get_nt_hash(machine_account, mem_ctx);
 419                 if (!mach_pwd) {
 420                         DEBUG(1, ("create_keytab: Domain trust informaton for account %s not available\n",
 421                                   cli_credentials_get_principal(machine_account, mem_ctx)));
 422                         talloc_free(mem_ctx);
 423                         return EINVAL;
 424                 }
 425                 ret = krb5_keyblock_init(smb_krb5_context->krb5_context,
 426                                          ETYPE_ARCFOUR_HMAC_MD5,
 427                                          mach_pwd->hash, sizeof(mach_pwd->hash),
 428                                          &entry.keyblock);
 429                 if (ret) {
 430                         DEBUG(1, ("create_keytab: krb5_keyblock_init failed: %s\n",
 431                                   smb_get_krb5_error_message(smb_krb5_context->krb5_context,
 432                                                              ret, mem_ctx)));
 433                         talloc_free(mem_ctx);
 434                         return ret;
 435                 }
 436
 437                 entry.principal = princ;
 438                 entry.vno       = cli_credentials_get_kvno(machine_account);
 439                 ret = krb5_kt_add_entry(smb_krb5_context->krb5_context, keytab, &entry);
 440                 if (ret) {
 441                         DEBUG(1, ("Failed to add ARCFOUR_HMAC (only) entry for %s to keytab: %s",
 442                                   cli_credentials_get_principal(machine_account, mem_ctx),
 443                                   smb_get_krb5_error_message(smb_krb5_context->krb5_context,
 444                                                              ret, mem_ctx)));
 445                         talloc_free(mem_ctx);
 446                         krb5_free_keyblock_contents(smb_krb5_context->krb5_context, &entry.keyblock);
 447                         return ret;
 448                 }
 449
 450                 krb5_enctype_to_string(smb_krb5_context->krb5_context,
 451                                        ETYPE_ARCFOUR_HMAC_MD5,
 452                                        &enctype_string);
 453                 DEBUG(5, ("Added %s(kvno %d) to keytab (%s)\n",
 454                           cli_credentials_get_principal(machine_account, mem_ctx),
 455                           cli_credentials_get_kvno(machine_account),
 456                           enctype_string));
 457                 free(enctype_string);
 458
 459                 krb5_free_keyblock_contents(smb_krb5_context->krb5_context, &entry.keyblock);
 460
 461                 /* Can't go any further, we only have this one key */
 462                 talloc_free(mem_ctx);
 463                 return 0;
 464         }
 465
 466         kvno = cli_credentials_get_kvno(machine_account);
 467         /* good, we actually have the real plaintext */
 468         ret = keytab_add_keys(mem_ctx, princ_string, princ, salt_princ,
 469                               kvno, password_s, smb_krb5_context, keytab);
 470         if (!ret) {
 471                 talloc_free(mem_ctx);
 472                 return ret;
 473         }
 474
 475         if (!add_old || kvno == 0) {
 476                 talloc_free(mem_ctx);
 477                 return 0;
 478         }
 479
 480         old_secret = cli_credentials_get_old_password(machine_account);
 481         if (!old_secret) {
 482                 talloc_free(mem_ctx);
 483                 return 0;
 484         }
 485
 486         ret = keytab_add_keys(mem_ctx, princ_string, princ, salt_princ,
 487                               kvno - 1, old_secret, smb_krb5_context, keytab);
 488         if (!ret) {
 489                 talloc_free(mem_ctx);
 490                 return ret;
 491         }
 492
 493         talloc_free(mem_ctx);
 494         return 0;
 495 }
 496
 497
 498 /*
 499  * Walk the keytab, looking for entries of this principal name, with KVNO other than current kvno -1.
 500  *
 501  * These entries are now stale, we only keep the current, and previous entries around.
 502  *
 503  * Inspired by the code in Samba3 for 'use kerberos keytab'.
 504  *
 505  */
 506
 507 static krb5_error_code remove_old_entries(TALLOC_CTX *parent_ctx,
 508                                           struct cli_credentials *machine_account,
 509                                           struct smb_krb5_context *smb_krb5_context,
 510                                           krb5_keytab keytab, BOOL *found_previous)
 511 {
 512         krb5_error_code ret, ret2;
 513         krb5_kt_cursor cursor;
 514         krb5_principal princ;
 515         int kvno;
 516         TALLOC_CTX *mem_ctx = talloc_new(parent_ctx);
 517         const char *princ_string;
 518         if (!mem_ctx) {
 519                 return ENOMEM;
 520         }
 521
 522         *found_previous = False;
 523         princ_string = cli_credentials_get_principal(machine_account, mem_ctx);
 524
 525         /* Get the principal we will store the new keytab entries under */
 526         ret = principal_from_credentials(mem_ctx, machine_account, smb_krb5_context, &princ);
 527         if (ret) {
 528                 DEBUG(1,("update_keytab: makeing krb5 principal failed (%s)\n",
 529                          smb_get_krb5_error_message(smb_krb5_context->krb5_context,
 530                                                     ret, mem_ctx)));
 531                 talloc_free(mem_ctx);
 532                 return ret;
 533         }
 534
 535         kvno = cli_credentials_get_kvno(machine_account);
 536
 537         /* for each entry in the keytab */
 538         ret = krb5_kt_start_seq_get(smb_krb5_context->krb5_context, keytab, &cursor);
 539         switch (ret) {
 540         case 0:
 541                 break;
 542         case HEIM_ERR_OPNOTSUPP:
 543         case ENOENT:
 544         case KRB5_KT_END:
 545                 /* no point enumerating if there isn't anything here */
 546                 talloc_free(mem_ctx);
 547                 return 0;
 548         default:
 549                 DEBUG(1,("failed to open keytab for read of old entries: %s\n",
 550                          smb_get_krb5_error_message(smb_krb5_context->krb5_context,
 551                                                     ret, mem_ctx)));
 552                 talloc_free(mem_ctx);
 553                 return ret;
 554         }
 555
 556         while (!ret) {
 557                 krb5_keytab_entry entry;
 558                 ret = krb5_kt_next_entry(smb_krb5_context->krb5_context, keytab, &entry, &cursor);
 559                 if (ret) {
 560                         break;
 561                 }
 562                 /* if it matches our principal */
 563                 if (!krb5_kt_compare(smb_krb5_context->krb5_context, &entry, princ, 0, 0)) {
 564                         /* Free the entry, it wasn't the one we were looking for anyway */
 565                         krb5_kt_free_entry(smb_krb5_context->krb5_context, &entry);
 566                         continue;
 567                 }
 568
 569                 /* delete it, if it is not kvno -1 */
 570                 if (entry.vno != (kvno - 1 )) {
 571                         /* Release the enumeration.  We are going to
 572                          * have to start this from the top again,
 573                          * because deletes during enumeration may not
 574                          * always be consistant.
 575                          *
 576                          * Also, the enumeration locks a FILE: keytab
 577                          */
 578
 579                         krb5_kt_end_seq_get(smb_krb5_context->krb5_context, keytab, &cursor);
 580
 581                         ret = krb5_kt_remove_entry(smb_krb5_context->krb5_context, keytab, &entry);
 582                         krb5_kt_free_entry(smb_krb5_context->krb5_context, &entry);
 583
 584                         /* Deleted: Restart from the top */
 585                         ret2 = krb5_kt_start_seq_get(smb_krb5_context->krb5_context, keytab, &cursor);
 586                         if (ret2) {
 587                                 krb5_kt_free_entry(smb_krb5_context->krb5_context, &entry);
 588                                 DEBUG(1,("failed to restart enumeration of keytab: %s\n",
 589                                          smb_get_krb5_error_message(smb_krb5_context->krb5_context,
 590                                                                     ret, mem_ctx)));
 591
 592                                 talloc_free(mem_ctx);
 593                                 return ret2;
 594                         }
 595
 596                         if (ret) {
 597                                 break;
 598                         }
 599
 600                 } else {
 601                         *found_previous = True;
 602                 }
 603
 604                 /* Free the entry, we don't need it any more */
 605                 krb5_kt_free_entry(smb_krb5_context->krb5_context, &entry);
 606
 607
 608         }
 609         krb5_kt_end_seq_get(smb_krb5_context->krb5_context, keytab, &cursor);
 610
 611         switch (ret) {
 612         case 0:
 613                 break;
 614         case ENOENT:
 615         case KRB5_KT_END:
 616                 ret = 0;
 617                 break;
 618         default:
 619                 DEBUG(1,("failed in deleting old entries for principal: %s: %s\n",
 620                          princ_string,
 621                          smb_get_krb5_error_message(smb_krb5_context->krb5_context,
 622                                                     ret, mem_ctx)));
 623         }
 624         talloc_free(mem_ctx);
 625         return ret;
 626 }
 627
 628 int smb_krb5_update_keytab(TALLOC_CTX *parent_ctx,
 629                            struct cli_credentials *machine_account,
 630                            struct smb_krb5_context *smb_krb5_context,
 631                            struct keytab_container *keytab_container)
 632 {
 633         krb5_error_code ret;
 634         BOOL found_previous;
 635         TALLOC_CTX *mem_ctx = talloc_new(parent_ctx);
 636         if (!mem_ctx) {
 637                 return ENOMEM;
 638         }
 639
 640         ret = remove_old_entries(mem_ctx, machine_account,
 641                                  smb_krb5_context, keytab_container->keytab, &found_previous);
 642         if (ret != 0) {
 643                 talloc_free(mem_ctx);
 644                 return ret;
 645         }
 646
 647         /* Create a new keytab.  If during the cleanout we found
 648          * entires for kvno -1, then don't try and duplicate them.
 649          * Otherwise, add kvno, and kvno -1 */
 650
 651         ret = create_keytab(mem_ctx, machine_account, smb_krb5_context,
 652                             keytab_container->keytab,
 653                             found_previous ? False : True);
 654         talloc_free(mem_ctx);
 655         return ret;
 656 }
 657
 658 int smb_krb5_create_memory_keytab(TALLOC_CTX *parent_ctx,
 659                                   struct cli_credentials *machine_account,
 660                                   struct smb_krb5_context *smb_krb5_context,
 661                                   struct keytab_container **keytab_container)
 662 {
 663         krb5_error_code ret;
 664         TALLOC_CTX *mem_ctx = talloc_new(parent_ctx);
 665         const char *rand_string;
 666         const char *keytab_name;
 667         if (!mem_ctx) {
 668                 return ENOMEM;
 669         }
 670
 671         *keytab_container = talloc(mem_ctx, struct keytab_container);
 672
 673         rand_string = generate_random_str(mem_ctx, 16);
 674         if (!rand_string) {
 675                 talloc_free(mem_ctx);
 676                 return ENOMEM;
 677         }
 678
 679         keytab_name = talloc_asprintf(mem_ctx, "MEMORY:%s",
 680                                       rand_string);
 681         if (!keytab_name) {
 682                 talloc_free(mem_ctx);
 683                 return ENOMEM;
 684         }
 685
 686         ret = smb_krb5_open_keytab(mem_ctx, smb_krb5_context, keytab_name, keytab_container);
 687         if (ret) {
 688                 return ret;
 689         }
 690
 691         ret = smb_krb5_update_keytab(mem_ctx, machine_account, smb_krb5_context, *keytab_container);
 692         if (ret == 0) {
 693                 talloc_steal(parent_ctx, *keytab_container);
 694         } else {
 695                 *keytab_container = NULL;
 696         }
 697         talloc_free(mem_ctx);
 698         return ret;
 699 }
 700