source4/kdc/wdc-samba4.c

   1 /*
   2    Unix SMB/CIFS implementation.
   3
   4    PAC Glue between Samba and the KDC
   5
   6    Copyright (C) Andrew Bartlett <abartlet@samba.org> 2005-2009
   7    Copyright (C) Simo Sorce <idra@samba.org> 2010
   8
   9    This program is free software; you can redistribute it and/or modify
  10    it under the terms of the GNU General Public License as published by
  11    the Free Software Foundation; either version 3 of the License, or
  12    (at your option) any later version.
  13
  14    This program is distributed in the hope that it will be useful,
  15    but WITHOUT ANY WARRANTY; without even the implied warranty of
  16    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17    GNU General Public License for more details.
  18
  19
  20    You should have received a copy of the GNU General Public License
  21    along with this program.  If not, see <http://www.gnu.org/licenses/>.
  22 */
  23
  24 #include "includes.h"
  25 #include "kdc/kdc-glue.h"
  26 #include "kdc/pac-glue.h"
  27
  28 /*
  29  * Given the right private pointer from hdb_samba4,
  30  * get a PAC from the attached ldb messages.
  31  *
  32  * For PKINIT we also get pk_reply_key and can add PAC_CREDENTIAL_INFO.
  33  */
  34 static krb5_error_code samba_wdc_get_pac(void *priv, krb5_context context,
  35                                          struct hdb_entry_ex *client,
  36                                          const krb5_keyblock *pk_reply_key,
  37                                          krb5_pac *pac)
  38 {
  39         TALLOC_CTX *mem_ctx;
  40         DATA_BLOB *logon_blob = NULL;
  41         DATA_BLOB *cred_ndr = NULL;
  42         DATA_BLOB **cred_ndr_ptr = NULL;
  43         DATA_BLOB _cred_blob = data_blob_null;
  44         DATA_BLOB *cred_blob = NULL;
  45         DATA_BLOB *upn_blob = NULL;
  46         krb5_error_code ret;
  47         NTSTATUS nt_status;
  48         struct samba_kdc_entry *skdc_entry =
  49                 talloc_get_type_abort(client->ctx,
  50                 struct samba_kdc_entry);
  51
  52         mem_ctx = talloc_named(client->ctx, 0, "samba_get_pac context");
  53         if (!mem_ctx) {
  54                 return ENOMEM;
  55         }
  56
  57         if (pk_reply_key != NULL) {
  58                 cred_ndr_ptr = &cred_ndr;
  59         }
  60
  61         nt_status = samba_kdc_get_pac_blobs(mem_ctx, skdc_entry,
  62                                             &logon_blob,
  63                                             cred_ndr_ptr,
  64                                             &upn_blob);
  65         if (!NT_STATUS_IS_OK(nt_status)) {
  66                 talloc_free(mem_ctx);
  67                 return EINVAL;
  68         }
  69
  70         if (pk_reply_key != NULL && cred_ndr != NULL) {
  71                 ret = samba_kdc_encrypt_pac_credentials(context,
  72                                                         pk_reply_key,
  73                                                         cred_ndr,
  74                                                         mem_ctx,
  75                                                         &_cred_blob);
  76                 if (ret != 0) {
  77                         talloc_free(mem_ctx);
  78                         return ret;
  79                 }
  80                 cred_blob = &_cred_blob;
  81         }
  82
  83         ret = samba_make_krb5_pac(context, logon_blob, cred_blob,
  84                                   upn_blob, NULL, pac);
  85
  86         talloc_free(mem_ctx);
  87         return ret;
  88 }
  89
  90 static krb5_error_code samba_wdc_get_pac_compat(void *priv, krb5_context context,
  91                                                 struct hdb_entry_ex *client,
  92                                                 krb5_pac *pac)
  93 {
  94         return samba_wdc_get_pac(priv, context, client, NULL, pac);
  95 }
  96
  97 /* Resign (and reform, including possibly new groups) a PAC */
  98
  99 static krb5_error_code samba_wdc_reget_pac(void *priv, krb5_context context,
 100                                            const krb5_principal client_principal,
 101                                            const krb5_principal delegated_proxy_principal,
 102                                            struct hdb_entry_ex *client,
 103                                            struct hdb_entry_ex *server,
 104                                            struct hdb_entry_ex *krbtgt,
 105                                            krb5_pac *pac)
 106 {
 107         struct samba_kdc_entry *p =
 108                 talloc_get_type_abort(server->ctx,
 109                 struct samba_kdc_entry);
 110         struct samba_kdc_entry *krbtgt_skdc_entry =
 111                 talloc_get_type_abort(krbtgt->ctx,
 112                 struct samba_kdc_entry);
 113         TALLOC_CTX *mem_ctx = talloc_named(p, 0, "samba_kdc_reget_pac context");
 114         krb5_pac new_pac = NULL;
 115         DATA_BLOB *pac_blob = NULL;
 116         DATA_BLOB *upn_blob = NULL;
 117         DATA_BLOB *deleg_blob = NULL;
 118         krb5_error_code ret;
 119         NTSTATUS nt_status;
 120         struct PAC_SIGNATURE_DATA *pac_srv_sig;
 121         struct PAC_SIGNATURE_DATA *pac_kdc_sig;
 122         bool is_in_db, is_untrusted;
 123         size_t num_types = 0;
 124         uint32_t *types = NULL;
 125         uint32_t forced_next_type = 0;
 126         size_t i = 0;
 127         ssize_t logon_info_idx = -1;
 128         ssize_t delegation_idx = -1;
 129         ssize_t logon_name_idx = -1;
 130         ssize_t upn_dns_info_idx = -1;
 131         ssize_t srv_checksum_idx = -1;
 132         ssize_t kdc_checksum_idx = -1;
 133
 134         if (!mem_ctx) {
 135                 return ENOMEM;
 136         }
 137
 138         /* The user account may be set not to want the PAC */
 139         if (!samba_princ_needs_pac(p)) {
 140                 talloc_free(mem_ctx);
 141                 return EINVAL;
 142         }
 143
 144         /* If the krbtgt was generated by an RODC, and we are not that
 145          * RODC, then we need to regenerate the PAC - we can't trust
 146          * it */
 147         ret = samba_krbtgt_is_in_db(krbtgt_skdc_entry, &is_in_db, &is_untrusted);
 148         if (ret != 0) {
 149                 talloc_free(mem_ctx);
 150                 return ret;
 151         }
 152
 153         if (is_untrusted) {
 154                 struct samba_kdc_entry *client_skdc_entry = NULL;
 155
 156                 if (client == NULL) {
 157                         return KRB5KDC_ERR_C_PRINCIPAL_UNKNOWN;
 158                 }
 159
 160                 client_skdc_entry = talloc_get_type_abort(client->ctx,
 161                                                           struct samba_kdc_entry);
 162
 163                 nt_status = samba_kdc_get_pac_blobs(mem_ctx, client_skdc_entry,
 164                                                     &pac_blob, NULL, &upn_blob);
 165                 if (!NT_STATUS_IS_OK(nt_status)) {
 166                         talloc_free(mem_ctx);
 167                         return EINVAL;
 168                 }
 169         } else {
 170                 pac_blob = talloc_zero(mem_ctx, DATA_BLOB);
 171                 if (!pac_blob) {
 172                         talloc_free(mem_ctx);
 173                         return ENOMEM;
 174                 }
 175
 176                 pac_srv_sig = talloc_zero(mem_ctx, struct PAC_SIGNATURE_DATA);
 177                 if (!pac_srv_sig) {
 178                         talloc_free(mem_ctx);
 179                         return ENOMEM;
 180                 }
 181
 182                 pac_kdc_sig = talloc_zero(mem_ctx, struct PAC_SIGNATURE_DATA);
 183                 if (!pac_kdc_sig) {
 184                         talloc_free(mem_ctx);
 185                         return ENOMEM;
 186                 }
 187
 188                 nt_status = samba_kdc_update_pac_blob(mem_ctx, context,
 189                                                       *pac, pac_blob,
 190                                                       pac_srv_sig, pac_kdc_sig);
 191                 if (!NT_STATUS_IS_OK(nt_status)) {
 192                         DEBUG(0, ("Building PAC failed: %s\n",
 193                                   nt_errstr(nt_status)));
 194                         talloc_free(mem_ctx);
 195                         return EINVAL;
 196                 }
 197
 198                 if (is_in_db) {
 199                         /* Now check the KDC signature, fetching the correct key based on the enc type */
 200                         ret = kdc_check_pac(context, pac_srv_sig->signature, pac_kdc_sig, krbtgt);
 201                         if (ret != 0) {
 202                                 DEBUG(1, ("PAC KDC signature failed to verify\n"));
 203                                 talloc_free(mem_ctx);
 204                                 return ret;
 205                         }
 206                 }
 207         }
 208
 209         if (delegated_proxy_principal) {
 210                 deleg_blob = talloc_zero(mem_ctx, DATA_BLOB);
 211                 if (!deleg_blob) {
 212                         talloc_free(mem_ctx);
 213                         return ENOMEM;
 214                 }
 215
 216                 nt_status = samba_kdc_update_delegation_info_blob(mem_ctx,
 217                                         context, *pac,
 218                                         server->entry.principal,
 219                                         delegated_proxy_principal,
 220                                         deleg_blob);
 221                 if (!NT_STATUS_IS_OK(nt_status)) {
 222                         DEBUG(0, ("Building PAC failed: %s\n",
 223                                   nt_errstr(nt_status)));
 224                         talloc_free(mem_ctx);
 225                         return EINVAL;
 226                 }
 227         }
 228
 229         /* Check the types of the given PAC */
 230         ret = krb5_pac_get_types(context, *pac, &num_types, &types);
 231         if (ret != 0) {
 232                 talloc_free(mem_ctx);
 233                 return ret;
 234         }
 235
 236         for (i = 0; i < num_types; i++) {
 237                 switch (types[i]) {
 238                 case PAC_TYPE_LOGON_INFO:
 239                         if (logon_info_idx != -1) {
 240                                 DEBUG(1, ("logon type[%d] twice [%d] and [%d]: \n",
 241                                           (int)types[i],
 242                                           (int)logon_info_idx,
 243                                           (int)i));
 244                                 SAFE_FREE(types);
 245                                 talloc_free(mem_ctx);
 246                                 return EINVAL;
 247                         }
 248                         logon_info_idx = i;
 249                         break;
 250                 case PAC_TYPE_CONSTRAINED_DELEGATION:
 251                         if (delegation_idx != -1) {
 252                                 DEBUG(1, ("logon type[%d] twice [%d] and [%d]: \n",
 253                                           (int)types[i],
 254                                           (int)logon_info_idx,
 255                                           (int)i));
 256                                 SAFE_FREE(types);
 257                                 talloc_free(mem_ctx);
 258                                 return EINVAL;
 259                         }
 260                         delegation_idx = i;
 261                         break;
 262                 case PAC_TYPE_LOGON_NAME:
 263                         if (logon_name_idx != -1) {
 264                                 DEBUG(1, ("logon type[%d] twice [%d] and [%d]: \n",
 265                                           (int)types[i],
 266                                           (int)logon_info_idx,
 267                                           (int)i));
 268                                 SAFE_FREE(types);
 269                                 talloc_free(mem_ctx);
 270                                 return EINVAL;
 271                         }
 272                         logon_name_idx = i;
 273                         break;
 274                 case PAC_TYPE_UPN_DNS_INFO:
 275                         if (upn_dns_info_idx != -1) {
 276                                 DEBUG(1, ("logon type[%d] twice [%d] and [%d]: \n",
 277                                           (int)types[i],
 278                                           (int)logon_info_idx,
 279                                           (int)i));
 280                                 SAFE_FREE(types);
 281                                 talloc_free(mem_ctx);
 282                                 return EINVAL;
 283                         }
 284                         upn_dns_info_idx = i;
 285                         break;
 286                 case PAC_TYPE_SRV_CHECKSUM:
 287                         if (srv_checksum_idx != -1) {
 288                                 DEBUG(1, ("logon type[%d] twice [%d] and [%d]: \n",
 289                                           (int)types[i],
 290                                           (int)logon_info_idx,
 291                                           (int)i));
 292                                 SAFE_FREE(types);
 293                                 talloc_free(mem_ctx);
 294                                 return EINVAL;
 295                         }
 296                         srv_checksum_idx = i;
 297                         break;
 298                 case PAC_TYPE_KDC_CHECKSUM:
 299                         if (kdc_checksum_idx != -1) {
 300                                 DEBUG(1, ("logon type[%d] twice [%d] and [%d]: \n",
 301                                           (int)types[i],
 302                                           (int)logon_info_idx,
 303                                           (int)i));
 304                                 SAFE_FREE(types);
 305                                 talloc_free(mem_ctx);
 306                                 return EINVAL;
 307                         }
 308                         kdc_checksum_idx = i;
 309                         break;
 310                 default:
 311                         continue;
 312                 }
 313         }
 314
 315         if (logon_info_idx == -1) {
 316                 DEBUG(1, ("PAC_TYPE_LOGON_INFO missing\n"));
 317                 SAFE_FREE(types);
 318                 talloc_free(mem_ctx);
 319                 return EINVAL;
 320         }
 321         if (logon_name_idx == -1) {
 322                 DEBUG(1, ("PAC_TYPE_LOGON_NAME missing\n"));
 323                 SAFE_FREE(types);
 324                 talloc_free(mem_ctx);
 325                 return EINVAL;
 326         }
 327         if (srv_checksum_idx == -1) {
 328                 DEBUG(1, ("PAC_TYPE_SRV_CHECKSUM missing\n"));
 329                 SAFE_FREE(types);
 330                 talloc_free(mem_ctx);
 331                 return EINVAL;
 332         }
 333         if (kdc_checksum_idx == -1) {
 334                 DEBUG(1, ("PAC_TYPE_KDC_CHECKSUM missing\n"));
 335                 SAFE_FREE(types);
 336                 talloc_free(mem_ctx);
 337                 return EINVAL;
 338         }
 339
 340         /* Build an updated PAC */
 341         ret = krb5_pac_init(context, &new_pac);
 342         if (ret != 0) {
 343                 SAFE_FREE(types);
 344                 talloc_free(mem_ctx);
 345                 return ret;
 346         }
 347
 348         for (i = 0;;) {
 349                 const uint8_t zero_byte = 0;
 350                 krb5_data type_data;
 351                 DATA_BLOB type_blob = data_blob_null;
 352                 uint32_t type;
 353
 354                 if (forced_next_type != 0) {
 355                         /*
 356                          * We need to inject possible missing types
 357                          */
 358                         type = forced_next_type;
 359                         forced_next_type = 0;
 360                 } else if (i < num_types) {
 361                         type = types[i];
 362                         i++;
 363                 } else {
 364                         break;
 365                 }
 366
 367                 switch (type) {
 368                 case PAC_TYPE_LOGON_INFO:
 369                         type_blob = *pac_blob;
 370
 371                         if (delegation_idx == -1 && deleg_blob != NULL) {
 372                                 /* inject CONSTRAINED_DELEGATION behind */
 373                                 forced_next_type = PAC_TYPE_CONSTRAINED_DELEGATION;
 374                         }
 375                         break;
 376                 case PAC_TYPE_CONSTRAINED_DELEGATION:
 377                         if (deleg_blob != NULL) {
 378                                 type_blob = *deleg_blob;
 379                         }
 380                         break;
 381                 case PAC_TYPE_CREDENTIAL_INFO:
 382                         /*
 383                          * Note that we copy the credential blob,
 384                          * as it's only usable with the PKINIT based
 385                          * AS-REP reply key, it's only available on the
 386                          * host which did the AS-REQ/AS-REP exchange.
 387                          *
 388                          * This matches Windows 2008R2...
 389                          */
 390                         break;
 391                 case PAC_TYPE_LOGON_NAME:
 392                         /*
 393                          * this is generated in the main KDC code
 394                          * we just add a place holder here.
 395                          */
 396                         type_blob = data_blob_const(&zero_byte, 1);
 397
 398                         if (upn_dns_info_idx == -1 && upn_blob != NULL) {
 399                                 /* inject UPN_DNS_INFO behind */
 400                                 forced_next_type = PAC_TYPE_UPN_DNS_INFO;
 401                         }
 402                         break;
 403                 case PAC_TYPE_UPN_DNS_INFO:
 404                         /*
 405                          * Replace in the RODC case, otherwise
 406                          * upn_blob is NULL and we just copy.
 407                          */
 408                         if (upn_blob != NULL) {
 409                                 type_blob = *upn_blob;
 410                         }
 411                         break;
 412                 case PAC_TYPE_SRV_CHECKSUM:
 413                         /*
 414                          * this are generated in the main KDC code
 415                          * we just add a place holder here.
 416                          */
 417                         type_blob = data_blob_const(&zero_byte, 1);
 418                         break;
 419                 case PAC_TYPE_KDC_CHECKSUM:
 420                         /*
 421                          * this are generated in the main KDC code
 422                          * we just add a place holders here.
 423                          */
 424                         type_blob = data_blob_const(&zero_byte, 1);
 425                         break;
 426                 default:
 427                         /* just copy... */
 428                         break;
 429                 }
 430
 431                 if (type_blob.length != 0) {
 432                         ret = krb5_copy_data_contents(&type_data,
 433                                                       type_blob.data,
 434                                                       type_blob.length);
 435                         if (ret != 0) {
 436                                 SAFE_FREE(types);
 437                                 krb5_pac_free(context, new_pac);
 438                                 talloc_free(mem_ctx);
 439                                 return ret;
 440                         }
 441                 } else {
 442                         ret = krb5_pac_get_buffer(context, *pac,
 443                                                   type, &type_data);
 444                         if (ret != 0) {
 445                                 SAFE_FREE(types);
 446                                 krb5_pac_free(context, new_pac);
 447                                 talloc_free(mem_ctx);
 448                                 return ret;
 449                         }
 450                 }
 451
 452                 ret = krb5_pac_add_buffer(context, new_pac,
 453                                           type, &type_data);
 454                 kerberos_free_data_contents(context, &type_data);
 455                 if (ret != 0) {
 456                         SAFE_FREE(types);
 457                         krb5_pac_free(context, new_pac);
 458                         talloc_free(mem_ctx);
 459                         return ret;
 460                 }
 461         }
 462
 463         SAFE_FREE(types);
 464
 465         /* We now replace the pac */
 466         krb5_pac_free(context, *pac);
 467         *pac = new_pac;
 468
 469         talloc_free(mem_ctx);
 470         return ret;
 471 }
 472
 473 static char *get_netbios_name(TALLOC_CTX *mem_ctx, HostAddresses *addrs)
 474 {
 475         char *nb_name = NULL;
 476         size_t len;
 477         unsigned int i;
 478
 479         for (i = 0; addrs && i < addrs->len; i++) {
 480                 if (addrs->val[i].addr_type != KRB5_ADDRESS_NETBIOS) {
 481                         continue;
 482                 }
 483                 len = MIN(addrs->val[i].address.length, 15);
 484                 nb_name = talloc_strndup(mem_ctx,
 485                                          addrs->val[i].address.data, len);
 486                 if (nb_name) {
 487                         break;
 488                 }
 489         }
 490
 491         if ((nb_name == NULL) || (nb_name[0] == '\0')) {
 492                 return NULL;
 493         }
 494
 495         /* Strip space padding */
 496         for (len = strlen(nb_name) - 1;
 497              (len > 0) && (nb_name[len] == ' ');
 498              --len) {
 499                 nb_name[len] = '\0';
 500         }
 501
 502         return nb_name;
 503 }
 504
 505 static krb5_data fill_krb5_data(void *data, size_t length)
 506 {
 507         krb5_data kdata;
 508
 509         kdata.data = data;
 510         kdata.length = length;
 511
 512         return kdata;
 513 }
 514
 515 /* this function allocates 'data' using malloc.
 516  * The caller is responsible for freeing it */
 517 static void samba_kdc_build_edata_reply(NTSTATUS nt_status, DATA_BLOB *e_data)
 518 {
 519         krb5_error_code ret = 0;
 520         PA_DATA pa;
 521         unsigned char *buf;
 522         size_t len;
 523
 524         if (!e_data)
 525                 return;
 526
 527         e_data->data   = NULL;
 528         e_data->length = 0;
 529
 530         pa.padata_type          = KRB5_PADATA_PW_SALT;
 531         pa.padata_value.length  = 12;
 532         pa.padata_value.data    = malloc(pa.padata_value.length);
 533         if (!pa.padata_value.data) {
 534                 e_data->length = 0;
 535                 e_data->data = NULL;
 536                 return;
 537         }
 538
 539         SIVAL(pa.padata_value.data, 0, NT_STATUS_V(nt_status));
 540         SIVAL(pa.padata_value.data, 4, 0);
 541         SIVAL(pa.padata_value.data, 8, 1);
 542
 543         ASN1_MALLOC_ENCODE(PA_DATA, buf, len, &pa, &len, ret);
 544         free(pa.padata_value.data);
 545         if (ret) {
 546                 return;
 547         }
 548
 549         e_data->data   = buf;
 550         e_data->length = len;
 551
 552         return;
 553 }
 554
 555
 556 static krb5_error_code samba_wdc_check_client_access(void *priv,
 557                                                      krb5_context context,
 558                                                      krb5_kdc_configuration *config,
 559                                                      hdb_entry_ex *client_ex, const char *client_name,
 560                                                      hdb_entry_ex *server_ex, const char *server_name,
 561                                                      KDC_REQ *req,
 562                                                      krb5_data *e_data)
 563 {
 564         struct samba_kdc_entry *kdc_entry;
 565         bool password_change;
 566         char *workstation;
 567         NTSTATUS nt_status;
 568
 569         kdc_entry = talloc_get_type(client_ex->ctx, struct samba_kdc_entry);
 570         password_change = (server_ex && server_ex->entry.flags.change_pw);
 571         workstation = get_netbios_name((TALLOC_CTX *)client_ex->ctx,
 572                                         req->req_body.addresses);
 573
 574         nt_status = samba_kdc_check_client_access(kdc_entry,
 575                                                   client_name,
 576                                                   workstation,
 577                                                   password_change);
 578
 579         if (!NT_STATUS_IS_OK(nt_status)) {
 580                 if (NT_STATUS_EQUAL(nt_status, NT_STATUS_NO_MEMORY)) {
 581                         return ENOMEM;
 582                 }
 583
 584                 if (e_data) {
 585                         DATA_BLOB data;
 586
 587                         samba_kdc_build_edata_reply(nt_status, &data);
 588                         *e_data = fill_krb5_data(data.data, data.length);
 589                 }
 590
 591                 return samba_kdc_map_policy_err(nt_status);
 592         }
 593
 594         /* Now do the standard Heimdal check */
 595         return kdc_check_flags(context, config,
 596                                client_ex, client_name,
 597                                server_ex, server_name,
 598                                req->msg_type == krb_as_req);
 599 }
 600
 601 static krb5_error_code samba_wdc_plugin_init(krb5_context context, void **ptr)
 602 {
 603         *ptr = NULL;
 604         return 0;
 605 }
 606
 607 static void samba_wdc_plugin_fini(void *ptr)
 608 {
 609         return;
 610 }
 611
 612 struct krb5plugin_windc_ftable windc_plugin_table = {
 613         .minor_version = KRB5_WINDC_PLUGIN_MINOR,
 614         .init = samba_wdc_plugin_init,
 615         .fini = samba_wdc_plugin_fini,
 616         .pac_generate = samba_wdc_get_pac_compat,
 617         .pac_verify = samba_wdc_reget_pac,
 618         .client_access = samba_wdc_check_client_access,
 619         .pac_pk_generate = samba_wdc_get_pac,
 620 };
 621
 622