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                                                       krbtgt_skdc_entry, p,
 190                                                       *pac, pac_blob,
 191                                                       pac_srv_sig, pac_kdc_sig);
 192                 if (!NT_STATUS_IS_OK(nt_status)) {
 193                         DEBUG(0, ("Building PAC failed: %s\n",
 194                                   nt_errstr(nt_status)));
 195                         talloc_free(mem_ctx);
 196                         return EINVAL;
 197                 }
 198
 199                 if (is_in_db) {
 200                         /* Now check the KDC signature, fetching the correct key based on the enc type */
 201                         ret = kdc_check_pac(context, pac_srv_sig->signature, pac_kdc_sig, krbtgt);
 202                         if (ret != 0) {
 203                                 DEBUG(1, ("PAC KDC signature failed to verify\n"));
 204                                 talloc_free(mem_ctx);
 205                                 return ret;
 206                         }
 207                 }
 208         }
 209
 210         if (delegated_proxy_principal) {
 211                 deleg_blob = talloc_zero(mem_ctx, DATA_BLOB);
 212                 if (!deleg_blob) {
 213                         talloc_free(mem_ctx);
 214                         return ENOMEM;
 215                 }
 216
 217                 nt_status = samba_kdc_update_delegation_info_blob(mem_ctx,
 218                                         context, *pac,
 219                                         server->entry.principal,
 220                                         delegated_proxy_principal,
 221                                         deleg_blob);
 222                 if (!NT_STATUS_IS_OK(nt_status)) {
 223                         DEBUG(0, ("Building PAC failed: %s\n",
 224                                   nt_errstr(nt_status)));
 225                         talloc_free(mem_ctx);
 226                         return EINVAL;
 227                 }
 228         }
 229
 230         /* Check the types of the given PAC */
 231         ret = krb5_pac_get_types(context, *pac, &num_types, &types);
 232         if (ret != 0) {
 233                 talloc_free(mem_ctx);
 234                 return ret;
 235         }
 236
 237         for (i = 0; i < num_types; i++) {
 238                 switch (types[i]) {
 239                 case PAC_TYPE_LOGON_INFO:
 240                         if (logon_info_idx != -1) {
 241                                 DEBUG(1, ("logon type[%d] twice [%d] and [%d]: \n",
 242                                           (int)types[i],
 243                                           (int)logon_info_idx,
 244                                           (int)i));
 245                                 SAFE_FREE(types);
 246                                 talloc_free(mem_ctx);
 247                                 return EINVAL;
 248                         }
 249                         logon_info_idx = i;
 250                         break;
 251                 case PAC_TYPE_CONSTRAINED_DELEGATION:
 252                         if (delegation_idx != -1) {
 253                                 DEBUG(1, ("logon type[%d] twice [%d] and [%d]: \n",
 254                                           (int)types[i],
 255                                           (int)logon_info_idx,
 256                                           (int)i));
 257                                 SAFE_FREE(types);
 258                                 talloc_free(mem_ctx);
 259                                 return EINVAL;
 260                         }
 261                         delegation_idx = i;
 262                         break;
 263                 case PAC_TYPE_LOGON_NAME:
 264                         if (logon_name_idx != -1) {
 265                                 DEBUG(1, ("logon type[%d] twice [%d] and [%d]: \n",
 266                                           (int)types[i],
 267                                           (int)logon_info_idx,
 268                                           (int)i));
 269                                 SAFE_FREE(types);
 270                                 talloc_free(mem_ctx);
 271                                 return EINVAL;
 272                         }
 273                         logon_name_idx = i;
 274                         break;
 275                 case PAC_TYPE_UPN_DNS_INFO:
 276                         if (upn_dns_info_idx != -1) {
 277                                 DEBUG(1, ("logon type[%d] twice [%d] and [%d]: \n",
 278                                           (int)types[i],
 279                                           (int)logon_info_idx,
 280                                           (int)i));
 281                                 SAFE_FREE(types);
 282                                 talloc_free(mem_ctx);
 283                                 return EINVAL;
 284                         }
 285                         upn_dns_info_idx = i;
 286                         break;
 287                 case PAC_TYPE_SRV_CHECKSUM:
 288                         if (srv_checksum_idx != -1) {
 289                                 DEBUG(1, ("logon type[%d] twice [%d] and [%d]: \n",
 290                                           (int)types[i],
 291                                           (int)logon_info_idx,
 292                                           (int)i));
 293                                 SAFE_FREE(types);
 294                                 talloc_free(mem_ctx);
 295                                 return EINVAL;
 296                         }
 297                         srv_checksum_idx = i;
 298                         break;
 299                 case PAC_TYPE_KDC_CHECKSUM:
 300                         if (kdc_checksum_idx != -1) {
 301                                 DEBUG(1, ("logon type[%d] twice [%d] and [%d]: \n",
 302                                           (int)types[i],
 303                                           (int)logon_info_idx,
 304                                           (int)i));
 305                                 SAFE_FREE(types);
 306                                 talloc_free(mem_ctx);
 307                                 return EINVAL;
 308                         }
 309                         kdc_checksum_idx = i;
 310                         break;
 311                 default:
 312                         continue;
 313                 }
 314         }
 315
 316         if (logon_info_idx == -1) {
 317                 DEBUG(1, ("PAC_TYPE_LOGON_INFO missing\n"));
 318                 SAFE_FREE(types);
 319                 talloc_free(mem_ctx);
 320                 return EINVAL;
 321         }
 322         if (logon_name_idx == -1) {
 323                 DEBUG(1, ("PAC_TYPE_LOGON_NAME missing\n"));
 324                 SAFE_FREE(types);
 325                 talloc_free(mem_ctx);
 326                 return EINVAL;
 327         }
 328         if (srv_checksum_idx == -1) {
 329                 DEBUG(1, ("PAC_TYPE_SRV_CHECKSUM missing\n"));
 330                 SAFE_FREE(types);
 331                 talloc_free(mem_ctx);
 332                 return EINVAL;
 333         }
 334         if (kdc_checksum_idx == -1) {
 335                 DEBUG(1, ("PAC_TYPE_KDC_CHECKSUM missing\n"));
 336                 SAFE_FREE(types);
 337                 talloc_free(mem_ctx);
 338                 return EINVAL;
 339         }
 340
 341         /* Build an updated PAC */
 342         ret = krb5_pac_init(context, &new_pac);
 343         if (ret != 0) {
 344                 SAFE_FREE(types);
 345                 talloc_free(mem_ctx);
 346                 return ret;
 347         }
 348
 349         for (i = 0;;) {
 350                 const uint8_t zero_byte = 0;
 351                 krb5_data type_data;
 352                 DATA_BLOB type_blob = data_blob_null;
 353                 uint32_t type;
 354
 355                 if (forced_next_type != 0) {
 356                         /*
 357                          * We need to inject possible missing types
 358                          */
 359                         type = forced_next_type;
 360                         forced_next_type = 0;
 361                 } else if (i < num_types) {
 362                         type = types[i];
 363                         i++;
 364                 } else {
 365                         break;
 366                 }
 367
 368                 switch (type) {
 369                 case PAC_TYPE_LOGON_INFO:
 370                         type_blob = *pac_blob;
 371
 372                         if (delegation_idx == -1 && deleg_blob != NULL) {
 373                                 /* inject CONSTRAINED_DELEGATION behind */
 374                                 forced_next_type = PAC_TYPE_CONSTRAINED_DELEGATION;
 375                         }
 376                         break;
 377                 case PAC_TYPE_CONSTRAINED_DELEGATION:
 378                         if (deleg_blob != NULL) {
 379                                 type_blob = *deleg_blob;
 380                         }
 381                         break;
 382                 case PAC_TYPE_CREDENTIAL_INFO:
 383                         /*
 384                          * Note that we copy the credential blob,
 385                          * as it's only usable with the PKINIT based
 386                          * AS-REP reply key, it's only available on the
 387                          * host which did the AS-REQ/AS-REP exchange.
 388                          *
 389                          * This matches Windows 2008R2...
 390                          */
 391                         break;
 392                 case PAC_TYPE_LOGON_NAME:
 393                         /*
 394                          * this is generated in the main KDC code
 395                          * we just add a place holder here.
 396                          */
 397                         type_blob = data_blob_const(&zero_byte, 1);
 398
 399                         if (upn_dns_info_idx == -1 && upn_blob != NULL) {
 400                                 /* inject UPN_DNS_INFO behind */
 401                                 forced_next_type = PAC_TYPE_UPN_DNS_INFO;
 402                         }
 403                         break;
 404                 case PAC_TYPE_UPN_DNS_INFO:
 405                         /*
 406                          * Replace in the RODC case, otherwise
 407                          * upn_blob is NULL and we just copy.
 408                          */
 409                         if (upn_blob != NULL) {
 410                                 type_blob = *upn_blob;
 411                         }
 412                         break;
 413                 case PAC_TYPE_SRV_CHECKSUM:
 414                         /*
 415                          * this are generated in the main KDC code
 416                          * we just add a place holder here.
 417                          */
 418                         type_blob = data_blob_const(&zero_byte, 1);
 419                         break;
 420                 case PAC_TYPE_KDC_CHECKSUM:
 421                         /*
 422                          * this are generated in the main KDC code
 423                          * we just add a place holders here.
 424                          */
 425                         type_blob = data_blob_const(&zero_byte, 1);
 426                         break;
 427                 default:
 428                         /* just copy... */
 429                         break;
 430                 }
 431
 432                 if (type_blob.length != 0) {
 433                         ret = smb_krb5_copy_data_contents(&type_data,
 434                                                           type_blob.data,
 435                                                           type_blob.length);
 436                         if (ret != 0) {
 437                                 SAFE_FREE(types);
 438                                 krb5_pac_free(context, new_pac);
 439                                 talloc_free(mem_ctx);
 440                                 return ret;
 441                         }
 442                 } else {
 443                         ret = krb5_pac_get_buffer(context, *pac,
 444                                                   type, &type_data);
 445                         if (ret != 0) {
 446                                 SAFE_FREE(types);
 447                                 krb5_pac_free(context, new_pac);
 448                                 talloc_free(mem_ctx);
 449                                 return ret;
 450                         }
 451                 }
 452
 453                 ret = krb5_pac_add_buffer(context, new_pac,
 454                                           type, &type_data);
 455                 smb_krb5_free_data_contents(context, &type_data);
 456                 if (ret != 0) {
 457                         SAFE_FREE(types);
 458                         krb5_pac_free(context, new_pac);
 459                         talloc_free(mem_ctx);
 460                         return ret;
 461                 }
 462         }
 463
 464         SAFE_FREE(types);
 465
 466         /* We now replace the pac */
 467         krb5_pac_free(context, *pac);
 468         *pac = new_pac;
 469
 470         talloc_free(mem_ctx);
 471         return ret;
 472 }
 473
 474 static char *get_netbios_name(TALLOC_CTX *mem_ctx, HostAddresses *addrs)
 475 {
 476         char *nb_name = NULL;
 477         size_t len;
 478         unsigned int i;
 479
 480         for (i = 0; addrs && i < addrs->len; i++) {
 481                 if (addrs->val[i].addr_type != KRB5_ADDRESS_NETBIOS) {
 482                         continue;
 483                 }
 484                 len = MIN(addrs->val[i].address.length, 15);
 485                 nb_name = talloc_strndup(mem_ctx,
 486                                          addrs->val[i].address.data, len);
 487                 if (nb_name) {
 488                         break;
 489                 }
 490         }
 491
 492         if ((nb_name == NULL) || (nb_name[0] == '\0')) {
 493                 return NULL;
 494         }
 495
 496         /* Strip space padding */
 497         for (len = strlen(nb_name) - 1;
 498              (len > 0) && (nb_name[len] == ' ');
 499              --len) {
 500                 nb_name[len] = '\0';
 501         }
 502
 503         return nb_name;
 504 }
 505
 506 static krb5_data fill_krb5_data(void *data, size_t length)
 507 {
 508         krb5_data kdata;
 509
 510         kdata.data = data;
 511         kdata.length = length;
 512
 513         return kdata;
 514 }
 515
 516 /* this function allocates 'data' using malloc.
 517  * The caller is responsible for freeing it */
 518 static void samba_kdc_build_edata_reply(NTSTATUS nt_status, DATA_BLOB *e_data)
 519 {
 520         krb5_error_code ret = 0;
 521         PA_DATA pa;
 522         unsigned char *buf;
 523         size_t len;
 524
 525         if (!e_data)
 526                 return;
 527
 528         e_data->data   = NULL;
 529         e_data->length = 0;
 530
 531         pa.padata_type          = KRB5_PADATA_PW_SALT;
 532         pa.padata_value.length  = 12;
 533         pa.padata_value.data    = malloc(pa.padata_value.length);
 534         if (!pa.padata_value.data) {
 535                 e_data->length = 0;
 536                 e_data->data = NULL;
 537                 return;
 538         }
 539
 540         SIVAL(pa.padata_value.data, 0, NT_STATUS_V(nt_status));
 541         SIVAL(pa.padata_value.data, 4, 0);
 542         SIVAL(pa.padata_value.data, 8, 1);
 543
 544         ASN1_MALLOC_ENCODE(PA_DATA, buf, len, &pa, &len, ret);
 545         free(pa.padata_value.data);
 546         if (ret) {
 547                 return;
 548         }
 549
 550         e_data->data   = buf;
 551         e_data->length = len;
 552
 553         return;
 554 }
 555
 556
 557 static krb5_error_code samba_wdc_check_client_access(void *priv,
 558                                                      krb5_context context,
 559                                                      krb5_kdc_configuration *config,
 560                                                      hdb_entry_ex *client_ex, const char *client_name,
 561                                                      hdb_entry_ex *server_ex, const char *server_name,
 562                                                      KDC_REQ *req,
 563                                                      krb5_data *e_data)
 564 {
 565         struct samba_kdc_entry *kdc_entry;
 566         bool password_change;
 567         char *workstation;
 568         NTSTATUS nt_status;
 569
 570         kdc_entry = talloc_get_type(client_ex->ctx, struct samba_kdc_entry);
 571         password_change = (server_ex && server_ex->entry.flags.change_pw);
 572         workstation = get_netbios_name((TALLOC_CTX *)client_ex->ctx,
 573                                         req->req_body.addresses);
 574
 575         nt_status = samba_kdc_check_client_access(kdc_entry,
 576                                                   client_name,
 577                                                   workstation,
 578                                                   password_change);
 579
 580         if (!NT_STATUS_IS_OK(nt_status)) {
 581                 if (NT_STATUS_EQUAL(nt_status, NT_STATUS_NO_MEMORY)) {
 582                         return ENOMEM;
 583                 }
 584
 585                 if (e_data) {
 586                         DATA_BLOB data;
 587
 588                         samba_kdc_build_edata_reply(nt_status, &data);
 589                         *e_data = fill_krb5_data(data.data, data.length);
 590                 }
 591
 592                 return samba_kdc_map_policy_err(nt_status);
 593         }
 594
 595         /* Now do the standard Heimdal check */
 596         return kdc_check_flags(context, config,
 597                                client_ex, client_name,
 598                                server_ex, server_name,
 599                                req->msg_type == krb_as_req);
 600 }
 601
 602 static krb5_error_code samba_wdc_plugin_init(krb5_context context, void **ptr)
 603 {
 604         *ptr = NULL;
 605         return 0;
 606 }
 607
 608 static void samba_wdc_plugin_fini(void *ptr)
 609 {
 610         return;
 611 }
 612
 613 struct krb5plugin_windc_ftable windc_plugin_table = {
 614         .minor_version = KRB5_WINDC_PLUGIN_MINOR,
 615         .init = samba_wdc_plugin_init,
 616         .fini = samba_wdc_plugin_fini,
 617         .pac_generate = samba_wdc_get_pac_compat,
 618         .pac_verify = samba_wdc_reget_pac,
 619         .client_access = samba_wdc_check_client_access,
 620         .pac_pk_generate = samba_wdc_get_pac,
 621 };
 622
 623