source4/auth/kerberos/kerberos_util.c

   1 /*
   2    Unix SMB/CIFS implementation.
   3
   4    Kerberos utility functions for GENSEC
   5
   6    Copyright (C) Andrew Bartlett <abartlet@samba.org> 2004-2005
   7
   8    This program is free software; you can redistribute it and/or modify
   9    it under the terms of the GNU General Public License as published by
  10    the Free Software Foundation; either version 3 of the License, or
  11    (at your option) any later version.
  12
  13    This program is distributed in the hope that it will be useful,
  14    but WITHOUT ANY WARRANTY; without even the implied warranty of
  15    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16    GNU General Public License for more details.
  17
  18
  19    You should have received a copy of the GNU General Public License
  20    along with this program.  If not, see <http://www.gnu.org/licenses/>.
  21 */
  22
  23 #include "includes.h"
  24 #include "system/kerberos.h"
  25 #include "auth/kerberos/kerberos.h"
  26 #include "auth/credentials/credentials.h"
  27 #include "auth/credentials/credentials_proto.h"
  28 #include "auth/credentials/credentials_krb5.h"
  29 #include "auth/kerberos/kerberos_credentials.h"
  30 #include "ldb.h"
  31 #include "param/secrets.h"
  32
  33 struct principal_container {
  34         struct smb_krb5_context *smb_krb5_context;
  35         krb5_principal principal;
  36         const char *string_form; /* Optional */
  37 };
  38
  39 static krb5_error_code free_principal(struct principal_container *pc)
  40 {
  41         /* current heimdal - 0.6.3, which we need anyway, fixes segfaults here */
  42         krb5_free_principal(pc->smb_krb5_context->krb5_context, pc->principal);
  43
  44         return 0;
  45 }
  46
  47
  48 static krb5_error_code parse_principal(TALLOC_CTX *parent_ctx,
  49                                        const char *princ_string,
  50                                        struct smb_krb5_context *smb_krb5_context,
  51                                        krb5_principal *princ,
  52                                        const char **error_string)
  53 {
  54         int ret;
  55         struct principal_container *mem_ctx;
  56         if (princ_string == NULL) {
  57                  *princ = NULL;
  58                  return 0;
  59         }
  60
  61         ret = krb5_parse_name(smb_krb5_context->krb5_context,
  62                               princ_string, princ);
  63
  64         if (ret) {
  65                 (*error_string) = smb_get_krb5_error_message(smb_krb5_context->krb5_context, ret, parent_ctx);
  66                 return ret;
  67         }
  68
  69         mem_ctx = talloc(parent_ctx, struct principal_container);
  70         if (!mem_ctx) {
  71                 (*error_string) = error_message(ENOMEM);
  72                 return ENOMEM;
  73         }
  74
  75         /* This song-and-dance effectivly puts the principal
  76          * into talloc, so we can't loose it. */
  77         mem_ctx->smb_krb5_context = talloc_reference(mem_ctx, smb_krb5_context);
  78         mem_ctx->principal = *princ;
  79         talloc_set_destructor(mem_ctx, free_principal);
  80         return 0;
  81 }
  82
  83 static krb5_error_code principals_from_msg(TALLOC_CTX *parent_ctx,
  84                                            struct ldb_message *msg,
  85                                            struct smb_krb5_context *smb_krb5_context,
  86                                            struct principal_container ***principals_out,
  87                                            const char **error_string)
  88 {
  89         unsigned int i;
  90         krb5_error_code ret;
  91         char *upper_realm;
  92         const char *realm = ldb_msg_find_attr_as_string(msg, "realm", NULL);
  93         const char *samAccountName = ldb_msg_find_attr_as_string(msg, "samAccountName", NULL);
  94         struct ldb_message_element *spn_el = ldb_msg_find_element(msg, "servicePrincipalName");
  95         TALLOC_CTX *tmp_ctx;
  96         struct principal_container **principals;
  97         tmp_ctx = talloc_new(parent_ctx);
  98         if (!tmp_ctx) {
  99                 *error_string = "Cannot allocate tmp_ctx";
 100                 return ENOMEM;
 101         }
 102
 103         if (!realm) {
 104                 *error_string = "Cannot have a kerberos secret in secrets.ldb without a realm";
 105                 return EINVAL;
 106         }
 107
 108         upper_realm = strupper_talloc(tmp_ctx, realm);
 109         if (!upper_realm) {
 110                 talloc_free(tmp_ctx);
 111                 *error_string = "Cannot allocate full upper case realm";
 112                 return ENOMEM;
 113         }
 114
 115         principals = talloc_array(tmp_ctx, struct principal_container *, spn_el ? (spn_el->num_values + 2) : 2);
 116
 117         spn_el = ldb_msg_find_element(msg, "servicePrincipalName");
 118         for (i=0; spn_el && i < spn_el->num_values; i++) {
 119                 principals[i] = talloc(principals, struct principal_container);
 120                 if (!principals[i]) {
 121                         talloc_free(tmp_ctx);
 122                         *error_string = "Cannot allocate mem_ctx";
 123                         return ENOMEM;
 124                 }
 125
 126                 principals[i]->smb_krb5_context = talloc_reference(principals[i], smb_krb5_context);
 127                 principals[i]->string_form = talloc_asprintf(principals[i], "%*.*s@%s",
 128                                                              (int)spn_el->values[i].length,
 129                                                              (int)spn_el->values[i].length,
 130                                                              (const char *)spn_el->values[i].data, upper_realm);
 131                 if (!principals[i]->string_form) {
 132                         talloc_free(tmp_ctx);
 133                         *error_string = "Cannot allocate full samAccountName";
 134                         return ENOMEM;
 135                 }
 136
 137                 ret = krb5_parse_name(smb_krb5_context->krb5_context,
 138                                       principals[i]->string_form, &principals[i]->principal);
 139
 140                 if (ret) {
 141                         talloc_free(tmp_ctx);
 142                         (*error_string) = smb_get_krb5_error_message(smb_krb5_context->krb5_context, ret, parent_ctx);
 143                         return ret;
 144                 }
 145
 146                 /* This song-and-dance effectivly puts the principal
 147                  * into talloc, so we can't loose it. */
 148                 talloc_set_destructor(principals[i], free_principal);
 149         }
 150
 151         if (samAccountName) {
 152                 principals[i] = talloc(principals, struct principal_container);
 153                 if (!principals[i]) {
 154                         talloc_free(tmp_ctx);
 155                         *error_string = "Cannot allocate mem_ctx";
 156                         return ENOMEM;
 157                 }
 158
 159                 principals[i]->smb_krb5_context = talloc_reference(principals[i], smb_krb5_context);
 160                 principals[i]->string_form = talloc_asprintf(parent_ctx, "%s@%s", samAccountName, upper_realm);
 161                 if (!principals[i]->string_form) {
 162                         talloc_free(tmp_ctx);
 163                         *error_string = "Cannot allocate full samAccountName";
 164                         return ENOMEM;
 165                 }
 166
 167                 ret = krb5_make_principal(smb_krb5_context->krb5_context, &principals[i]->principal, upper_realm, samAccountName,
 168                                           NULL);
 169                 if (ret) {
 170                         talloc_free(tmp_ctx);
 171                         (*error_string) = smb_get_krb5_error_message(smb_krb5_context->krb5_context, ret, parent_ctx);
 172                         return ret;
 173                 }
 174
 175                 /* This song-and-dance effectivly puts the principal
 176                  * into talloc, so we can't loose it. */
 177                 talloc_set_destructor(principals[i], free_principal);
 178                 i++;
 179         }
 180
 181         principals[i] = NULL;
 182         *principals_out = talloc_steal(parent_ctx, principals);
 183
 184         talloc_free(tmp_ctx);
 185         return ret;
 186 }
 187
 188 static krb5_error_code salt_principal_from_msg(TALLOC_CTX *parent_ctx,
 189                                                struct ldb_message *msg,
 190                                                struct smb_krb5_context *smb_krb5_context,
 191                                                krb5_principal *salt_princ,
 192                                                const char **error_string)
 193 {
 194         const char *salt_principal = ldb_msg_find_attr_as_string(msg, "saltPrincipal", NULL);
 195         const char *samAccountName = ldb_msg_find_attr_as_string(msg, "samAccountName", NULL);
 196         const char *realm = ldb_msg_find_attr_as_string(msg, "realm", NULL);
 197         if (salt_principal) {
 198                 return parse_principal(parent_ctx, salt_principal, smb_krb5_context, salt_princ, error_string);
 199         } else if (samAccountName) {
 200                 krb5_error_code ret;
 201                 char *machine_username;
 202                 char *salt_body;
 203                 char *lower_realm;
 204                 char *upper_realm;
 205
 206                 TALLOC_CTX *tmp_ctx;
 207                 struct principal_container *mem_ctx = talloc(parent_ctx, struct principal_container);
 208                 if (!mem_ctx) {
 209                         *error_string = "Cannot allocate mem_ctx";
 210                         return ENOMEM;
 211                 }
 212
 213                 tmp_ctx = talloc_new(mem_ctx);
 214                 if (!tmp_ctx) {
 215                         talloc_free(mem_ctx);
 216                         *error_string = "Cannot allocate tmp_ctx";
 217                         return ENOMEM;
 218                 }
 219
 220                 if (!realm) {
 221                         *error_string = "Cannot have a kerberos secret in secrets.ldb without a realm";
 222                         return EINVAL;
 223                 }
 224
 225                 machine_username = talloc_strdup(tmp_ctx, samAccountName);
 226                 if (!machine_username) {
 227                         talloc_free(mem_ctx);
 228                         *error_string = "Cannot duplicate samAccountName";
 229                         return ENOMEM;
 230                 }
 231
 232                 if (machine_username[strlen(machine_username)-1] == '$') {
 233                         machine_username[strlen(machine_username)-1] = '\0';
 234                 }
 235
 236                 lower_realm = strlower_talloc(tmp_ctx, realm);
 237                 if (!lower_realm) {
 238                         talloc_free(mem_ctx);
 239                         *error_string = "Cannot allocate to lower case realm";
 240                         return ENOMEM;
 241                 }
 242
 243                 upper_realm = strupper_talloc(tmp_ctx, realm);
 244                 if (!upper_realm) {
 245                         talloc_free(mem_ctx);
 246                         *error_string = "Cannot allocate to upper case realm";
 247                         return ENOMEM;
 248                 }
 249
 250                 salt_body = talloc_asprintf(tmp_ctx, "%s.%s", machine_username,
 251                                             lower_realm);
 252                 talloc_free(lower_realm);
 253                 talloc_free(machine_username);
 254                 if (!salt_body) {
 255                         talloc_free(mem_ctx);
 256                         *error_string = "Cannot form salt principal body";
 257                         return ENOMEM;
 258                 }
 259
 260                 ret = krb5_make_principal(smb_krb5_context->krb5_context, salt_princ,
 261                                           upper_realm,
 262                                           "host", salt_body, NULL);
 263                 if (ret == 0) {
 264                         /* This song-and-dance effectivly puts the principal
 265                          * into talloc, so we can't loose it. */
 266                         mem_ctx->smb_krb5_context = talloc_reference(mem_ctx, smb_krb5_context);
 267                         mem_ctx->principal = *salt_princ;
 268                         talloc_set_destructor(mem_ctx, free_principal);
 269                 } else {
 270                         (*error_string) = smb_get_krb5_error_message(smb_krb5_context->krb5_context, ret, parent_ctx);
 271                 }
 272                 talloc_free(tmp_ctx);
 273                 return ret;
 274         } else {
 275                 (*error_string) = "Cannot determine salt principal, no saltPrincipal or samAccountName specified";
 276                 return EINVAL;
 277         }
 278 }
 279
 280 /* Obtain the principal set on this context.  Requires a
 281  * smb_krb5_context because we are doing krb5 principal parsing with
 282  * the library routines.  The returned princ is placed in the talloc
 283  * system by means of a destructor (do *not* free). */
 284
 285 krb5_error_code principal_from_credentials(TALLOC_CTX *parent_ctx,
 286                                             struct cli_credentials *credentials,
 287                                             struct smb_krb5_context *smb_krb5_context,
 288                                             krb5_principal *princ,
 289                                             enum credentials_obtained *obtained,
 290                                             const char **error_string)
 291 {
 292         krb5_error_code ret;
 293         const char *princ_string;
 294         TALLOC_CTX *mem_ctx = talloc_new(parent_ctx);
 295         if (!mem_ctx) {
 296                 (*error_string) = error_message(ENOMEM);
 297                 return ENOMEM;
 298         }
 299         princ_string = cli_credentials_get_principal_and_obtained(credentials, mem_ctx, obtained);
 300         if (!princ_string) {
 301                 (*error_string) = error_message(ENOMEM);
 302                 return ENOMEM;
 303         }
 304
 305         ret = parse_principal(parent_ctx, princ_string,
 306                               smb_krb5_context, princ, error_string);
 307         talloc_free(mem_ctx);
 308         return ret;
 309 }
 310
 311 /* Obtain the principal set on this context.  Requires a
 312  * smb_krb5_context because we are doing krb5 principal parsing with
 313  * the library routines.  The returned princ is placed in the talloc
 314  * system by means of a destructor (do *not* free). */
 315
 316  krb5_error_code impersonate_principal_from_credentials(TALLOC_CTX *parent_ctx,
 317                                                         struct cli_credentials *credentials,
 318                                                         struct smb_krb5_context *smb_krb5_context,
 319                                                         krb5_principal *princ,
 320                                                         const char **error_string)
 321 {
 322         return parse_principal(parent_ctx, cli_credentials_get_impersonate_principal(credentials),
 323                                smb_krb5_context, princ, error_string);
 324 }
 325
 326 /**
 327  * Return a freshly allocated ccache (destroyed by destructor on child
 328  * of parent_ctx), for a given set of client credentials
 329  */
 330
 331  krb5_error_code kinit_to_ccache(TALLOC_CTX *parent_ctx,
 332                                  struct cli_credentials *credentials,
 333                                  struct smb_krb5_context *smb_krb5_context,
 334                                  krb5_ccache ccache,
 335                                  enum credentials_obtained *obtained,
 336                                  const char **error_string)
 337 {
 338         krb5_error_code ret;
 339         const char *password, *target_service;
 340         time_t kdc_time = 0;
 341         krb5_principal princ;
 342         krb5_principal impersonate_principal;
 343         int tries;
 344         TALLOC_CTX *mem_ctx = talloc_new(parent_ctx);
 345         krb5_get_init_creds_opt *krb_options;
 346
 347         if (!mem_ctx) {
 348                 (*error_string) = strerror(ENOMEM);
 349                 return ENOMEM;
 350         }
 351
 352         ret = principal_from_credentials(mem_ctx, credentials, smb_krb5_context, &princ, obtained, error_string);
 353         if (ret) {
 354                 talloc_free(mem_ctx);
 355                 return ret;
 356         }
 357
 358         ret = impersonate_principal_from_credentials(mem_ctx, credentials, smb_krb5_context, &impersonate_principal, error_string);
 359         if (ret) {
 360                 talloc_free(mem_ctx);
 361                 return ret;
 362         }
 363
 364         target_service = cli_credentials_get_target_service(credentials);
 365
 366         password = cli_credentials_get_password(credentials);
 367
 368         /* setup the krb5 options we want */
 369         if ((ret = krb5_get_init_creds_opt_alloc(smb_krb5_context->krb5_context, &krb_options))) {
 370                 (*error_string) = talloc_asprintf(credentials, "krb5_get_init_creds_opt_alloc failed (%s)\n",
 371                                                   smb_get_krb5_error_message(smb_krb5_context->krb5_context,
 372                                                                              ret, mem_ctx));
 373                 talloc_free(mem_ctx);
 374                 return ret;
 375         }
 376
 377         /* get the defaults */
 378         krb5_get_init_creds_opt_set_default_flags(smb_krb5_context->krb5_context, NULL, NULL, krb_options);
 379
 380         /* set if we want a forwardable ticket */
 381         switch (cli_credentials_get_krb_forwardable(credentials)) {
 382         case CRED_AUTO_KRB_FORWARDABLE:
 383                 break;
 384         case CRED_NO_KRB_FORWARDABLE:
 385                 krb5_get_init_creds_opt_set_forwardable(krb_options, FALSE);
 386                 break;
 387         case CRED_FORCE_KRB_FORWARDABLE:
 388                 krb5_get_init_creds_opt_set_forwardable(krb_options, TRUE);
 389                 break;
 390         }
 391
 392         tries = 2;
 393         while (tries--) {
 394                 if (password) {
 395                         ret = kerberos_kinit_password_cc(smb_krb5_context->krb5_context, ccache,
 396                                                          princ, password,
 397                                                          impersonate_principal, target_service,
 398                                                          krb_options,
 399                                                          NULL, &kdc_time);
 400                 } else if (impersonate_principal) {
 401                         (*error_string) = "INTERNAL error: Cannot impersonate principal with just a keyblock.  A password must be specified in the credentials";
 402                         return EINVAL;
 403                 } else {
 404                         /* No password available, try to use a keyblock instead */
 405
 406                         krb5_keyblock keyblock;
 407                         const struct samr_Password *mach_pwd;
 408                         mach_pwd = cli_credentials_get_nt_hash(credentials, mem_ctx);
 409                         if (!mach_pwd) {
 410                                 talloc_free(mem_ctx);
 411                                 (*error_string) = "kinit_to_ccache: No password available for kinit\n";
 412                                 krb5_get_init_creds_opt_free(smb_krb5_context->krb5_context, krb_options);
 413                                 return EINVAL;
 414                         }
 415                         ret = krb5_keyblock_init(smb_krb5_context->krb5_context,
 416                                                  ENCTYPE_ARCFOUR_HMAC,
 417                                                  mach_pwd->hash, sizeof(mach_pwd->hash),
 418                                                  &keyblock);
 419
 420                         if (ret == 0) {
 421                                 ret = kerberos_kinit_keyblock_cc(smb_krb5_context->krb5_context, ccache,
 422                                                                  princ, &keyblock,
 423                                                                  target_service, krb_options,
 424                                                                  NULL, &kdc_time);
 425                                 krb5_free_keyblock_contents(smb_krb5_context->krb5_context, &keyblock);
 426                         }
 427                 }
 428
 429                 if (ret == KRB5KRB_AP_ERR_SKEW || ret == KRB5_KDCREP_SKEW) {
 430                         /* Perhaps we have been given an invalid skew, so try again without it */
 431                         time_t t = time(NULL);
 432                         krb5_set_real_time(smb_krb5_context->krb5_context, t, 0);
 433                 } else {
 434                         /* not a skew problem */
 435                         break;
 436                 }
 437         }
 438
 439         krb5_get_init_creds_opt_free(smb_krb5_context->krb5_context, krb_options);
 440
 441         if (ret == KRB5KRB_AP_ERR_SKEW || ret == KRB5_KDCREP_SKEW) {
 442                 (*error_string) = talloc_asprintf(credentials, "kinit for %s failed (%s)\n",
 443                                                   cli_credentials_get_principal(credentials, mem_ctx),
 444                                                   smb_get_krb5_error_message(smb_krb5_context->krb5_context,
 445                                                                              ret, mem_ctx));
 446                 talloc_free(mem_ctx);
 447                 return ret;
 448         }
 449
 450         /* cope with ticket being in the future due to clock skew */
 451         if ((unsigned)kdc_time > time(NULL)) {
 452                 time_t t = time(NULL);
 453                 int time_offset =(unsigned)kdc_time-t;
 454                 DEBUG(4,("Advancing clock by %d seconds to cope with clock skew\n", time_offset));
 455                 krb5_set_real_time(smb_krb5_context->krb5_context, t + time_offset + 1, 0);
 456         }
 457
 458         if (ret == KRB5KDC_ERR_PREAUTH_FAILED && cli_credentials_wrong_password(credentials)) {
 459                 ret = kinit_to_ccache(parent_ctx,
 460                                       credentials,
 461                                       smb_krb5_context,
 462                                       ccache, obtained,
 463                                       error_string);
 464         }
 465
 466         if (ret) {
 467                 (*error_string) = talloc_asprintf(credentials, "kinit for %s failed (%s)\n",
 468                                                   cli_credentials_get_principal(credentials, mem_ctx),
 469                                                   smb_get_krb5_error_message(smb_krb5_context->krb5_context,
 470                                                                              ret, mem_ctx));
 471                 talloc_free(mem_ctx);
 472                 return ret;
 473         }
 474         talloc_free(mem_ctx);
 475         return 0;
 476 }
 477
 478 static krb5_error_code free_keytab(struct keytab_container *ktc)
 479 {
 480         return krb5_kt_close(ktc->smb_krb5_context->krb5_context, ktc->keytab);
 481 }
 482
 483 krb5_error_code smb_krb5_open_keytab(TALLOC_CTX *mem_ctx,
 484                          struct smb_krb5_context *smb_krb5_context,
 485                          const char *keytab_name, struct keytab_container **ktc)
 486 {
 487         krb5_keytab keytab;
 488         krb5_error_code ret;
 489         ret = krb5_kt_resolve(smb_krb5_context->krb5_context, keytab_name, &keytab);
 490         if (ret) {
 491                 DEBUG(1,("failed to open krb5 keytab: %s\n",
 492                          smb_get_krb5_error_message(smb_krb5_context->krb5_context,
 493                                                     ret, mem_ctx)));
 494                 return ret;
 495         }
 496
 497         *ktc = talloc(mem_ctx, struct keytab_container);
 498         if (!*ktc) {
 499                 return ENOMEM;
 500         }
 501
 502         (*ktc)->smb_krb5_context = talloc_reference(*ktc, smb_krb5_context);
 503         (*ktc)->keytab = keytab;
 504         talloc_set_destructor(*ktc, free_keytab);
 505
 506         return 0;
 507 }
 508
 509 static krb5_error_code keytab_add_keys(TALLOC_CTX *parent_ctx,
 510                                        const char *princ_string,
 511                                        krb5_principal princ,
 512                                        krb5_principal salt_princ,
 513                                        int kvno,
 514                                        const char *password_s,
 515                                        struct smb_krb5_context *smb_krb5_context,
 516                                        krb5_enctype *enctypes,
 517                                        krb5_keytab keytab,
 518                                        const char **error_string)
 519 {
 520         int i;
 521         krb5_error_code ret;
 522         krb5_data password;
 523         TALLOC_CTX *mem_ctx = talloc_new(parent_ctx);
 524         if (!mem_ctx) {
 525                 return ENOMEM;
 526         }
 527
 528         password.data = discard_const_p(char *, password_s);
 529         password.length = strlen(password_s);
 530
 531         for (i=0; enctypes[i]; i++) {
 532                 krb5_keytab_entry entry;
 533                 ret = create_kerberos_key_from_string(smb_krb5_context->krb5_context,
 534                                                       salt_princ, &password, &entry.keyblock, enctypes[i]);
 535                 if (ret != 0) {
 536                         talloc_free(mem_ctx);
 537                         return ret;
 538                 }
 539
 540                 entry.principal = princ;
 541                 entry.vno       = kvno;
 542                 ret = krb5_kt_add_entry(smb_krb5_context->krb5_context, keytab, &entry);
 543                 if (ret != 0) {
 544                         *error_string = talloc_asprintf(parent_ctx, "Failed to add enctype %d entry for %s(kvno %d) to keytab: %s\n",
 545                                                         (int)enctypes[i],
 546                                                         princ_string,
 547                                                         kvno,
 548                                                         smb_get_krb5_error_message(smb_krb5_context->krb5_context,
 549                                                                                    ret, mem_ctx));
 550                         talloc_free(mem_ctx);
 551                         krb5_free_keyblock_contents(smb_krb5_context->krb5_context, &entry.keyblock);
 552                         return ret;
 553                 }
 554
 555                 DEBUG(5, ("Added %s(kvno %d) to keytab (enctype %d)\n",
 556                           princ_string, kvno,
 557                           (int)enctypes[i]));
 558
 559                 krb5_free_keyblock_contents(smb_krb5_context->krb5_context, &entry.keyblock);
 560         }
 561         talloc_free(mem_ctx);
 562         return 0;
 563 }
 564
 565 static krb5_error_code create_keytab(TALLOC_CTX *parent_ctx,
 566                                      struct ldb_message *msg,
 567                                      struct principal_container **principals,
 568                                      struct smb_krb5_context *smb_krb5_context,
 569                                      krb5_keytab keytab,
 570                                      bool add_old,
 571                                      const char **error_string)
 572 {
 573         unsigned int i;
 574         krb5_error_code ret;
 575         const char *password_s;
 576         const char *old_secret;
 577         int kvno;
 578         uint32_t enctype_bitmap;
 579         krb5_principal salt_princ;
 580         krb5_enctype *enctypes;
 581         TALLOC_CTX *mem_ctx = talloc_new(parent_ctx);
 582         if (!mem_ctx) {
 583                 *error_string = "unable to allocate tmp_ctx for create_keytab";
 584                 return ENOMEM;
 585         }
 586
 587         /* The salt used to generate these entries may be different however, fetch that */
 588         ret = salt_principal_from_msg(mem_ctx, msg,
 589                                       smb_krb5_context,
 590                                       &salt_princ, error_string);
 591         if (ret) {
 592                 talloc_free(mem_ctx);
 593                 return ret;
 594         }
 595
 596         kvno = ldb_msg_find_attr_as_int(msg, "msDS-KeyVersionNumber", 0);
 597
 598         /* Finally, do the dance to get the password to put in the entry */
 599         password_s =  ldb_msg_find_attr_as_string(msg, "secret", NULL);
 600         if (add_old && kvno != 0) {
 601                 old_secret = ldb_msg_find_attr_as_string(msg, "priorSecret", NULL);
 602         } else {
 603                 old_secret = NULL;
 604         }
 605
 606         enctype_bitmap = (uint32_t)ldb_msg_find_attr_as_int(msg, "msDS-SupportedEncryptionTypes", ENC_ALL_TYPES);
 607
 608         ret = kerberos_enctype_bitmap_to_enctypes(mem_ctx, enctype_bitmap, &enctypes);
 609         if (ret) {
 610                 *error_string = talloc_asprintf(parent_ctx, "create_keytab: generating list of encryption types failed (%s)\n",
 611                                                 smb_get_krb5_error_message(smb_krb5_context->krb5_context,
 612                                                                            ret, mem_ctx));
 613                 talloc_free(mem_ctx);
 614                 return ret;
 615         }
 616
 617         /* Walk over the principals */
 618         for (i=0; principals[i]; i++) {
 619                 ret = keytab_add_keys(mem_ctx, principals[i]->string_form, principals[i]->principal,
 620                                       salt_princ,
 621                                       kvno, password_s, smb_krb5_context,
 622                                       enctypes, keytab, error_string);
 623                 if (ret) {
 624                         talloc_free(mem_ctx);
 625                         return ret;
 626                 }
 627
 628                 if (old_secret) {
 629                         ret = keytab_add_keys(mem_ctx, principals[i]->string_form, principals[i]->principal,
 630                                               salt_princ,
 631                                               kvno - 1, old_secret, smb_krb5_context,
 632                                               enctypes, keytab, error_string);
 633                         if (ret) {
 634                                 talloc_free(mem_ctx);
 635                                 return ret;
 636                         }
 637                 }
 638         }
 639
 640         talloc_free(mem_ctx);
 641         return ret;
 642 }
 643
 644 /*
 645  * Walk the keytab, looking for entries of this principal name, with KVNO other than current kvno -1.
 646  *
 647  * These entries are now stale, we only keep the current, and previous entries around.
 648  *
 649  * Inspired by the code in Samba3 for 'use kerberos keytab'.
 650  *
 651  */
 652
 653 static krb5_error_code remove_old_entries(TALLOC_CTX *parent_ctx,
 654                                           struct ldb_message *msg,
 655                                           struct principal_container **principals,
 656                                           bool delete_all_kvno,
 657                                           struct smb_krb5_context *smb_krb5_context,
 658                                           krb5_keytab keytab, bool *found_previous,
 659                                           const char **error_string)
 660 {
 661         krb5_error_code ret, ret2;
 662         krb5_kt_cursor cursor;
 663         int kvno;
 664         TALLOC_CTX *mem_ctx = talloc_new(parent_ctx);
 665
 666         if (!mem_ctx) {
 667                 return ENOMEM;
 668         }
 669
 670         *found_previous = false;
 671
 672         kvno = ldb_msg_find_attr_as_int(msg, "msDS-KeyVersionNumber", 0);
 673
 674         /* for each entry in the keytab */
 675         ret = krb5_kt_start_seq_get(smb_krb5_context->krb5_context, keytab, &cursor);
 676         switch (ret) {
 677         case 0:
 678                 break;
 679         case HEIM_ERR_OPNOTSUPP:
 680         case ENOENT:
 681         case KRB5_KT_END:
 682                 /* no point enumerating if there isn't anything here */
 683                 talloc_free(mem_ctx);
 684                 return 0;
 685         default:
 686                 *error_string = talloc_asprintf(parent_ctx, "failed to open keytab for read of old entries: %s\n",
 687                                                 smb_get_krb5_error_message(smb_krb5_context->krb5_context,
 688                                                                            ret, mem_ctx));
 689                 talloc_free(mem_ctx);
 690                 return ret;
 691         }
 692
 693         while (!ret) {
 694                 unsigned int i;
 695                 bool matched = false;
 696                 krb5_keytab_entry entry;
 697                 ret = krb5_kt_next_entry(smb_krb5_context->krb5_context, keytab, &entry, &cursor);
 698                 if (ret) {
 699                         break;
 700                 }
 701                 for (i = 0; principals[i]; i++) {
 702                         /* if it matches our principal */
 703                         if (krb5_kt_compare(smb_krb5_context->krb5_context, &entry, principals[i]->principal, 0, 0)) {
 704                                 matched = true;
 705                                 break;
 706                         }
 707                 }
 708
 709                 if (!matched) {
 710                         /* Free the entry, it wasn't the one we were looking for anyway */
 711                         krb5_kt_free_entry(smb_krb5_context->krb5_context, &entry);
 712                         continue;
 713                 }
 714
 715                 /* delete it, if it is not kvno -1 */
 716                 if (entry.vno != (kvno - 1 )) {
 717                         /* Release the enumeration.  We are going to
 718                          * have to start this from the top again,
 719                          * because deletes during enumeration may not
 720                          * always be consistant.
 721                          *
 722                          * Also, the enumeration locks a FILE: keytab
 723                          */
 724
 725                         krb5_kt_end_seq_get(smb_krb5_context->krb5_context, keytab, &cursor);
 726
 727                         ret = krb5_kt_remove_entry(smb_krb5_context->krb5_context, keytab, &entry);
 728                         krb5_kt_free_entry(smb_krb5_context->krb5_context, &entry);
 729
 730                         /* Deleted: Restart from the top */
 731                         ret2 = krb5_kt_start_seq_get(smb_krb5_context->krb5_context, keytab, &cursor);
 732                         if (ret2) {
 733                                 krb5_kt_free_entry(smb_krb5_context->krb5_context, &entry);
 734                                 DEBUG(1,("failed to restart enumeration of keytab: %s\n",
 735                                          smb_get_krb5_error_message(smb_krb5_context->krb5_context,
 736                                                                     ret, mem_ctx)));
 737
 738                                 talloc_free(mem_ctx);
 739                                 return ret2;
 740                         }
 741
 742                         if (ret) {
 743                                 break;
 744                         }
 745
 746                 } else {
 747                         *found_previous = true;
 748                 }
 749
 750                 /* Free the entry, we don't need it any more */
 751                 krb5_kt_free_entry(smb_krb5_context->krb5_context, &entry);
 752
 753
 754         }
 755         krb5_kt_end_seq_get(smb_krb5_context->krb5_context, keytab, &cursor);
 756
 757         switch (ret) {
 758         case 0:
 759                 break;
 760         case ENOENT:
 761         case KRB5_KT_END:
 762                 ret = 0;
 763                 break;
 764         default:
 765                 *error_string = talloc_asprintf(parent_ctx, "failed in deleting old entries for principal: %s\n",
 766                                                 smb_get_krb5_error_message(smb_krb5_context->krb5_context,
 767                                                                            ret, mem_ctx));
 768         }
 769         talloc_free(mem_ctx);
 770         return ret;
 771 }
 772
 773 krb5_error_code smb_krb5_update_keytab(TALLOC_CTX *parent_ctx,
 774                                        struct smb_krb5_context *smb_krb5_context,
 775                                        struct ldb_context *ldb,
 776                                        struct ldb_message *msg,
 777                                        bool delete_all_kvno,
 778                                        const char **error_string)
 779 {
 780         krb5_error_code ret;
 781         bool found_previous;
 782         TALLOC_CTX *mem_ctx = talloc_new(NULL);
 783         struct keytab_container *keytab_container;
 784         struct principal_container **principals;
 785         const char *keytab_name;
 786
 787         if (!mem_ctx) {
 788                 return ENOMEM;
 789         }
 790
 791         keytab_name = keytab_name_from_msg(mem_ctx, ldb, msg);
 792         if (!keytab_name) {
 793                 return ENOENT;
 794         }
 795
 796         ret = smb_krb5_open_keytab(mem_ctx, smb_krb5_context, keytab_name, &keytab_container);
 797
 798         if (ret != 0) {
 799                 talloc_free(mem_ctx);
 800                 return ret;
 801         }
 802
 803         DEBUG(5, ("Opened keytab %s\n", keytab_name));
 804
 805         /* Get the principal we will store the new keytab entries under */
 806         ret = principals_from_msg(mem_ctx, msg, smb_krb5_context, &principals, error_string);
 807
 808         if (ret != 0) {
 809                 *error_string = talloc_asprintf(parent_ctx, "Failed to load principals from ldb message: %s\n", *error_string);
 810                 talloc_free(mem_ctx);
 811                 return ret;
 812         }
 813
 814         ret = remove_old_entries(mem_ctx, msg, principals, delete_all_kvno,
 815                                  smb_krb5_context, keytab_container->keytab, &found_previous, error_string);
 816         if (ret != 0) {
 817                 *error_string = talloc_asprintf(parent_ctx, "Failed to remove old principals from keytab: %s\n", *error_string);
 818                 talloc_free(mem_ctx);
 819                 return ret;
 820         }
 821
 822         if (!delete_all_kvno) {
 823                 /* Create a new keytab.  If during the cleanout we found
 824                  * entires for kvno -1, then don't try and duplicate them.
 825                  * Otherwise, add kvno, and kvno -1 */
 826
 827                 ret = create_keytab(mem_ctx, msg, principals,
 828                                     smb_krb5_context,
 829                                     keytab_container->keytab,
 830                                     found_previous ? false : true, error_string);
 831         }
 832         talloc_free(mem_ctx);
 833         return ret;
 834 }
 835
 836 krb5_error_code smb_krb5_create_memory_keytab(TALLOC_CTX *parent_ctx,
 837                                            struct cli_credentials *machine_account,
 838                                            struct smb_krb5_context *smb_krb5_context,
 839                                            struct keytab_container **keytab_container)
 840 {
 841         krb5_error_code ret;
 842         TALLOC_CTX *mem_ctx = talloc_new(parent_ctx);
 843         const char *rand_string;
 844         const char *keytab_name;
 845         struct ldb_message *msg;
 846         const char *error_string;
 847         if (!mem_ctx) {
 848                 return ENOMEM;
 849         }
 850
 851         *keytab_container = talloc(mem_ctx, struct keytab_container);
 852
 853         rand_string = generate_random_str(mem_ctx, 16);
 854         if (!rand_string) {
 855                 talloc_free(mem_ctx);
 856                 return ENOMEM;
 857         }
 858
 859         keytab_name = talloc_asprintf(mem_ctx, "MEMORY:%s",
 860                                       rand_string);
 861         if (!keytab_name) {
 862                 talloc_free(mem_ctx);
 863                 return ENOMEM;
 864         }
 865
 866         ret = smb_krb5_open_keytab(mem_ctx, smb_krb5_context, keytab_name, keytab_container);
 867         if (ret) {
 868                 return ret;
 869         }
 870
 871         msg = ldb_msg_new(mem_ctx);
 872         if (!msg) {
 873                 talloc_free(mem_ctx);
 874                 return ENOMEM;
 875         }
 876         ldb_msg_add_string(msg, "krb5Keytab", keytab_name);
 877         ldb_msg_add_string(msg, "secret", cli_credentials_get_password(machine_account));
 878         ldb_msg_add_string(msg, "samAccountName", cli_credentials_get_username(machine_account));
 879         ldb_msg_add_string(msg, "realm", cli_credentials_get_realm(machine_account));
 880         ldb_msg_add_fmt(msg, "msDS-KeyVersionNumber", "%d", (int)cli_credentials_get_kvno(machine_account));
 881
 882         ret = smb_krb5_update_keytab(mem_ctx, smb_krb5_context, NULL, msg, false, &error_string);
 883         if (ret == 0) {
 884                 talloc_steal(parent_ctx, *keytab_container);
 885         } else {
 886                 DEBUG(0, ("Failed to create in-memory keytab: %s\n", error_string));
 887                 *keytab_container = NULL;
 888         }
 889         talloc_free(mem_ctx);
 890         return ret;
 891 }
 892 /* Translate between the IETF encryption type values and the Microsoft msDS-SupportedEncryptionTypes values */
 893 uint32_t kerberos_enctype_to_bitmap(krb5_enctype enc_type_enum)
 894 {
 895         switch (enc_type_enum) {
 896         case ENCTYPE_DES_CBC_CRC:
 897                 return ENC_CRC32;
 898         case ENCTYPE_DES_CBC_MD5:
 899                 return ENC_RSA_MD5;
 900         case ENCTYPE_ARCFOUR_HMAC_MD5:
 901                 return ENC_RC4_HMAC_MD5;
 902         case ENCTYPE_AES128_CTS_HMAC_SHA1_96:
 903                 return ENC_HMAC_SHA1_96_AES128;
 904         case ENCTYPE_AES256_CTS_HMAC_SHA1_96:
 905                 return ENC_HMAC_SHA1_96_AES256;
 906         default:
 907                 return 0;
 908         }
 909 }
 910
 911 /* Translate between the Microsoft msDS-SupportedEncryptionTypes values and the IETF encryption type values */
 912 krb5_enctype kerberos_enctype_bitmap_to_enctype(uint32_t enctype_bitmap)
 913 {
 914         switch (enctype_bitmap) {
 915         case ENC_CRC32:
 916                 return ENCTYPE_DES_CBC_CRC;
 917         case ENC_RSA_MD5:
 918                 return ENCTYPE_DES_CBC_MD5;
 919         case ENC_RC4_HMAC_MD5:
 920                 return ENCTYPE_ARCFOUR_HMAC_MD5;
 921         case ENC_HMAC_SHA1_96_AES128:
 922                 return ENCTYPE_AES128_CTS_HMAC_SHA1_96;
 923         case ENC_HMAC_SHA1_96_AES256:
 924                 return ENCTYPE_AES256_CTS_HMAC_SHA1_96;
 925         default:
 926                 return 0;
 927         }
 928 }
 929
 930 /* Return an array of krb5_enctype values */
 931 krb5_error_code kerberos_enctype_bitmap_to_enctypes(TALLOC_CTX *mem_ctx, uint32_t enctype_bitmap, krb5_enctype **enctypes)
 932 {
 933         unsigned int i, j = 0;
 934         *enctypes = talloc_zero_array(mem_ctx, krb5_enctype, (8*sizeof(enctype_bitmap))+1);
 935         if (!*enctypes) {
 936                 return ENOMEM;
 937         }
 938         for (i=0; i<(8*sizeof(enctype_bitmap)); i++) {
 939                 uint32_t bit_value = (1 << i) & enctype_bitmap;
 940                 if (bit_value & enctype_bitmap) {
 941                         (*enctypes)[j] = kerberos_enctype_bitmap_to_enctype(bit_value);
 942                         if (!(*enctypes)[j]) {
 943                                 continue;
 944                         }
 945                         j++;
 946                 }
 947         }
 948         (*enctypes)[j] = 0;
 949         return 0;
 950 }