source3/winbindd/idmap_hash/idmap_hash.c

   1 /*
   2  *  idmap_hash.c
   3  *
   4  * Copyright (C) Gerald Carter  <jerry@samba.org>      2007 - 2008
   5  *
   6  *  This program is free software; you can redistribute it and/or modify
   7  *  it under the terms of the GNU General Public License as published by
   8  *  the Free Software Foundation; either version 3 of the License, or
   9  *  (at your option) any later version.
  10  *
  11  *  This program is distributed in the hope that it will be useful,
  12  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  *  GNU General Public License for more details.
  15  *
  16  *  You should have received a copy of the GNU General Public License
  17  *  along with this program; if not, see <http://www.gnu.org/licenses/>.
  18  *
  19  */
  20
  21 #include "includes.h"
  22 #include "winbindd/winbindd.h"
  23 #include "idmap.h"
  24 #include "idmap_hash.h"
  25 #include "ads.h"
  26 #include "nss_info.h"
  27 #include "../libcli/security/dom_sid.h"
  28 #include "libsmb/samlogon_cache.h"
  29
  30 #undef DBGC_CLASS
  31 #define DBGC_CLASS DBGC_IDMAP
  32
  33 struct sid_hash_table {
  34         struct dom_sid *sid;
  35 };
  36
  37 /*********************************************************************
  38  Hash a domain SID (S-1-5-12-aaa-bbb-ccc) to a 12bit number
  39  ********************************************************************/
  40
  41 static uint32_t hash_domain_sid(const struct dom_sid *sid)
  42 {
  43         uint32_t hash;
  44
  45         if (sid->num_auths != 4)
  46                 return 0;
  47
  48         /* XOR the last three subauths */
  49
  50         hash = ((sid->sub_auths[1] ^ sid->sub_auths[2]) ^ sid->sub_auths[3]);
  51
  52         /* Take all 32-bits into account when generating the 12-bit
  53            hash value */
  54         hash = (((hash & 0xFFF00000) >> 20)
  55                 + ((hash & 0x000FFF00) >> 8)
  56                 + (hash & 0x000000FF)) & 0x0000FFF;
  57
  58         /* return a 12-bit hash value */
  59
  60         return hash;
  61 }
  62
  63 /*********************************************************************
  64  Hash a Relative ID to a 19 bit number
  65  ********************************************************************/
  66
  67 static uint32_t hash_rid(uint32_t rid)
  68 {
  69         /*
  70          * 19 bits for the rid which allows us to support
  71          * the first 50K users/groups in a domain
  72          *
  73          */
  74
  75         return (rid & 0x0007FFFF);
  76 }
  77
  78 /*********************************************************************
  79  ********************************************************************/
  80
  81 static uint32_t combine_hashes(uint32_t h_domain,
  82                                uint32_t h_rid)
  83 {
  84         uint32_t return_id = 0;
  85
  86         /*
  87          * shift the hash_domain 19 bits to the left and OR with the
  88          * hash_rid
  89          *
  90          * This will generate a 31 bit number out of
  91          * 12 bit domain and 19 bit rid.
  92          */
  93
  94         return_id = ((h_domain<<19) | h_rid);
  95
  96         return return_id;
  97 }
  98
  99 /*********************************************************************
 100  ********************************************************************/
 101
 102 static void separate_hashes(uint32_t id,
 103                             uint32_t *h_domain,
 104                             uint32_t *h_rid)
 105 {
 106         *h_rid = id & 0x0007FFFF;
 107         *h_domain = (id & 0x7FF80000) >> 19;
 108
 109         return;
 110 }
 111
 112
 113 /*********************************************************************
 114  ********************************************************************/
 115
 116 static NTSTATUS idmap_hash_initialize(struct idmap_domain *dom)
 117 {
 118         struct sid_hash_table *hashed_domains;
 119         NTSTATUS nt_status = NT_STATUS_UNSUCCESSFUL;
 120         struct winbindd_tdc_domain *dom_list = NULL;
 121         size_t num_domains = 0;
 122         size_t i;
 123
 124         DBG_ERR("The idmap_hash module is deprecated and should not be used. "
 125                 "Please migrate to a different plugin. This module will be "
 126                 "removed in a future version of Samba\n");
 127
 128         if (!strequal(dom->name, "*")) {
 129                 DBG_ERR("Error: idmap_hash configured for domain '%s'. "
 130                         "But the hash module can only be used for the default "
 131                         "idmap configuration.\n", dom->name);
 132                 return NT_STATUS_INVALID_PARAMETER;
 133         }
 134
 135         if (!wcache_tdc_fetch_list(&dom_list, &num_domains)) {
 136                 nt_status = NT_STATUS_TRUSTED_DOMAIN_FAILURE;
 137                 BAIL_ON_NTSTATUS_ERROR(nt_status);
 138         }
 139
 140         /* Create the hash table of domain SIDs */
 141
 142         hashed_domains = talloc_zero_array(dom, struct sid_hash_table, 4096);
 143         BAIL_ON_PTR_NT_ERROR(hashed_domains, nt_status);
 144
 145         /* create the hash table of domain SIDs */
 146
 147         for (i=0; i<num_domains; i++) {
 148                 struct dom_sid_buf buf;
 149                 uint32_t hash;
 150
 151                 if (is_null_sid(&dom_list[i].sid))
 152                         continue;
 153
 154                 /*
 155                  * Check if the domain from the list is not already configured
 156                  * to use another idmap backend. Not checking this makes the
 157                  * idmap_hash module map IDs for *all* domains implicitly.  This
 158                  * is quite dangerous in setups that use multiple idmap
 159                  * configurations.
 160                  */
 161
 162                 if (domain_has_idmap_config(dom_list[i].domain_name)) {
 163                         continue;
 164                 }
 165
 166                 if ((hash = hash_domain_sid(&dom_list[i].sid)) == 0)
 167                         continue;
 168
 169                 DBG_INFO("Adding %s (%s) -> %d\n",
 170                          dom_list[i].domain_name,
 171                          dom_sid_str_buf(&dom_list[i].sid, &buf),
 172                          hash);
 173
 174                 hashed_domains[hash].sid = talloc(hashed_domains, struct dom_sid);
 175                 sid_copy(hashed_domains[hash].sid, &dom_list[i].sid);
 176         }
 177
 178         dom->private_data = hashed_domains;
 179
 180 done:
 181         return nt_status;
 182 }
 183
 184 /*********************************************************************
 185  ********************************************************************/
 186
 187 static NTSTATUS idmap_hash_id_to_sid(struct sid_hash_table *hashed_domains,
 188                                      struct idmap_domain *dom,
 189                                      struct id_map *id)
 190 {
 191         uint32_t h_domain = 0, h_rid = 0;
 192
 193         id->status = ID_UNMAPPED;
 194
 195         separate_hashes(id->xid.id, &h_domain, &h_rid);
 196
 197         /*
 198          * If the domain hash doesn't find a SID in the table,
 199          * skip it
 200          */
 201         if (hashed_domains[h_domain].sid == NULL) {
 202                 /* keep ID_UNMAPPED */
 203                 return NT_STATUS_OK;
 204         }
 205
 206         id->xid.type = ID_TYPE_BOTH;
 207         sid_compose(id->sid, hashed_domains[h_domain].sid, h_rid);
 208         id->status = ID_MAPPED;
 209
 210         return NT_STATUS_OK;
 211 }
 212
 213 static NTSTATUS unixids_to_sids(struct idmap_domain *dom,
 214                                 struct id_map **ids)
 215 {
 216         struct sid_hash_table *hashed_domains = talloc_get_type_abort(
 217                 dom->private_data, struct sid_hash_table);
 218         size_t i;
 219         size_t num_tomap = 0;
 220         size_t num_mapped = 0;
 221
 222         /* initialize the status to avoid surprise */
 223         for (i = 0; ids[i]; i++) {
 224                 ids[i]->status = ID_UNKNOWN;
 225                 num_tomap++;
 226         }
 227
 228         for (i=0; ids[i]; i++) {
 229                 NTSTATUS ret;
 230
 231                 ret = idmap_hash_id_to_sid(hashed_domains, dom, ids[i]);
 232                 if (!NT_STATUS_IS_OK(ret)) {
 233                         /* some fatal error occurred, log it */
 234                         DBG_NOTICE("Unexpected error resolving an ID "
 235                                    "(%d): %s\n", ids[i]->xid.id,
 236                                    nt_errstr(ret));
 237                         return ret;
 238                 }
 239
 240                 if (ids[i]->status == ID_MAPPED) {
 241                         num_mapped++;
 242                 }
 243         }
 244
 245         if (num_tomap == num_mapped) {
 246                 return NT_STATUS_OK;
 247         } else if (num_mapped == 0) {
 248                 return NT_STATUS_NONE_MAPPED;
 249         }
 250
 251         return STATUS_SOME_UNMAPPED;
 252 }
 253
 254 /*********************************************************************
 255  ********************************************************************/
 256
 257 static NTSTATUS idmap_hash_sid_to_id(struct sid_hash_table *hashed_domains,
 258                                      struct idmap_domain *dom,
 259                                      struct id_map *id)
 260 {
 261         struct dom_sid sid;
 262         uint32_t rid;
 263         uint32_t h_domain, h_rid;
 264
 265         id->status = ID_UNMAPPED;
 266
 267         sid_copy(&sid, id->sid);
 268         sid_split_rid(&sid, &rid);
 269
 270         h_domain = hash_domain_sid(&sid);
 271         h_rid = hash_rid(rid);
 272
 273         /* Check that both hashes are non-zero*/
 274         if (h_domain == 0) {
 275                 /* keep ID_UNMAPPED */
 276                 return NT_STATUS_OK;
 277         }
 278         if (h_rid == 0) {
 279                 /* keep ID_UNMAPPED */
 280                 return NT_STATUS_OK;
 281         }
 282
 283         /*
 284          * If the domain hash already exists find a SID in the table,
 285          * just return the mapping.
 286          */
 287         if (hashed_domains[h_domain].sid != NULL) {
 288                 goto return_mapping;
 289         }
 290
 291         /*
 292          * Check of last resort: A domain is valid if a user from that
 293          * domain has recently logged in. The samlogon_cache these
 294          * days also stores the domain sid.
 295          */
 296         if (netsamlogon_cache_have(&sid)) {
 297                 /*
 298                  * The domain is valid, so we'll
 299                  * remember it in order to
 300                  * allow reverse mappings to work.
 301                  */
 302                 goto remember_domain;
 303         }
 304
 305         if (id->xid.type == ID_TYPE_NOT_SPECIFIED) {
 306                 /*
 307                  * idmap_hash used to bounce back the requested type,
 308                  * which was ID_TYPE_UID, ID_TYPE_GID or
 309                  * ID_TYPE_NOT_SPECIFIED before as the winbindd parent
 310                  * always used a lookupsids.  When the lookupsids
 311                  * failed because of an unknown domain, the idmap child
 312                  * weren't requested at all and the caller sees
 313                  * ID_TYPE_NOT_SPECIFIED.
 314                  *
 315                  * Now that the winbindd parent will pass ID_TYPE_BOTH
 316                  * in order to indicate that the domain exists.
 317                  * We should ask the parent to fallback to lookupsids
 318                  * if the domain is not known yet.
 319                  */
 320                 id->status = ID_REQUIRE_TYPE;
 321                 return NT_STATUS_OK;
 322         }
 323
 324         /*
 325          * Now we're sure the domain exist, remember
 326          * the domain in order to return reverse mappings
 327          * in future.
 328          */
 329 remember_domain:
 330         hashed_domains[h_domain].sid = dom_sid_dup(hashed_domains, &sid);
 331         if (hashed_domains[h_domain].sid == NULL) {
 332                 return NT_STATUS_NO_MEMORY;
 333         }
 334
 335         /*
 336          * idmap_hash used to bounce back the requested type,
 337          * which was ID_TYPE_UID, ID_TYPE_GID or
 338          * ID_TYPE_NOT_SPECIFIED before as the winbindd parent
 339          * always used a lookupsids.
 340          *
 341          * This module should have supported ID_TYPE_BOTH since
 342          * samba-4.1.0, similar to idmap_rid and idmap_autorid.
 343          *
 344          * Now that the winbindd parent will pass ID_TYPE_BOTH
 345          * in order to indicate that the domain exists, it's
 346          * better to always return ID_TYPE_BOTH instead of a
 347          * random mix of ID_TYPE_UID, ID_TYPE_GID or
 348          * ID_TYPE_BOTH.
 349          */
 350 return_mapping:
 351         id->xid.type = ID_TYPE_BOTH;
 352         id->xid.id = combine_hashes(h_domain, h_rid);
 353         id->status = ID_MAPPED;
 354
 355         return NT_STATUS_OK;
 356 }
 357
 358 static NTSTATUS sids_to_unixids(struct idmap_domain *dom,
 359                                 struct id_map **ids)
 360 {
 361         struct sid_hash_table *hashed_domains = talloc_get_type_abort(
 362                 dom->private_data, struct sid_hash_table);
 363         size_t i;
 364         size_t num_tomap = 0;
 365         size_t num_mapped = 0;
 366         size_t num_required = 0;
 367
 368         /* initialize the status to avoid surprise */
 369         for (i = 0; ids[i]; i++) {
 370                 ids[i]->status = ID_UNKNOWN;
 371                 num_tomap++;
 372         }
 373
 374         for (i=0; ids[i]; i++) {
 375                 NTSTATUS ret;
 376
 377                 ret = idmap_hash_sid_to_id(hashed_domains, dom, ids[i]);
 378                 if (!NT_STATUS_IS_OK(ret)) {
 379                         struct dom_sid_buf buf;
 380                         /* some fatal error occurred, log it */
 381                         DBG_NOTICE("Unexpected error resolving a SID "
 382                                    "(%s): %s\n",
 383                                    dom_sid_str_buf(ids[i]->sid, &buf),
 384                                    nt_errstr(ret));
 385                         return ret;
 386                 }
 387
 388                 if (ids[i]->status == ID_MAPPED) {
 389                         num_mapped++;
 390                 }
 391                 if (ids[i]->status == ID_REQUIRE_TYPE) {
 392                         num_required++;
 393                 }
 394         }
 395
 396         if (num_tomap == num_mapped) {
 397                 return NT_STATUS_OK;
 398         } else if (num_required > 0) {
 399                 return STATUS_SOME_UNMAPPED;
 400         } else if (num_mapped == 0) {
 401                 return NT_STATUS_NONE_MAPPED;
 402         }
 403
 404         return STATUS_SOME_UNMAPPED;
 405 }
 406
 407 /*********************************************************************
 408  ********************************************************************/
 409
 410 static NTSTATUS nss_hash_init(struct nss_domain_entry *e )
 411 {
 412         return NT_STATUS_OK;
 413 }
 414
 415 /**********************************************************************
 416  *********************************************************************/
 417
 418 static NTSTATUS nss_hash_map_to_alias(TALLOC_CTX *mem_ctx,
 419                                         struct nss_domain_entry *e,
 420                                         const char *name,
 421                                         char **alias)
 422 {
 423         NTSTATUS nt_status = NT_STATUS_UNSUCCESSFUL;
 424         const char *value;
 425
 426         value = talloc_asprintf(mem_ctx, "%s\\%s", e->domain, name);
 427         BAIL_ON_PTR_NT_ERROR(value, nt_status);
 428
 429         nt_status = mapfile_lookup_key(mem_ctx, value, alias);
 430         BAIL_ON_NTSTATUS_ERROR(nt_status);
 431
 432 done:
 433         return nt_status;
 434 }
 435
 436 /**********************************************************************
 437  *********************************************************************/
 438
 439 static NTSTATUS nss_hash_map_from_alias(TALLOC_CTX *mem_ctx,
 440                                           struct nss_domain_entry *e,
 441                                           const char *alias,
 442                                           char **name)
 443 {
 444         return mapfile_lookup_value(mem_ctx, alias, name);
 445 }
 446
 447 /**********************************************************************
 448  *********************************************************************/
 449
 450 static NTSTATUS nss_hash_close(void)
 451 {
 452         return NT_STATUS_OK;
 453 }
 454
 455 /*********************************************************************
 456  Dispatch Tables for IDMap and NssInfo Methods
 457 ********************************************************************/
 458
 459 static const struct idmap_methods hash_idmap_methods = {
 460         .init            = idmap_hash_initialize,
 461         .unixids_to_sids = unixids_to_sids,
 462         .sids_to_unixids = sids_to_unixids,
 463 };
 464
 465 static const struct nss_info_methods hash_nss_methods = {
 466         .init           = nss_hash_init,
 467         .map_to_alias   = nss_hash_map_to_alias,
 468         .map_from_alias = nss_hash_map_from_alias,
 469         .close_fn       = nss_hash_close
 470 };
 471
 472 /**********************************************************************
 473  Register with the idmap and idmap_nss subsystems. We have to protect
 474  against the idmap and nss_info interfaces being in a half-registered
 475  state.
 476  **********************************************************************/
 477
 478 static_decl_idmap;
 479 NTSTATUS idmap_hash_init(TALLOC_CTX *ctx)
 480 {
 481         static NTSTATUS idmap_status = NT_STATUS_UNSUCCESSFUL;
 482         static NTSTATUS nss_status = NT_STATUS_UNSUCCESSFUL;
 483
 484         if ( !NT_STATUS_IS_OK(idmap_status) ) {
 485                 idmap_status =  smb_register_idmap(SMB_IDMAP_INTERFACE_VERSION,
 486                                                    "hash", &hash_idmap_methods);
 487
 488                 if ( !NT_STATUS_IS_OK(idmap_status) ) {
 489                         DEBUG(0,("Failed to register hash idmap plugin.\n"));
 490                         return idmap_status;
 491                 }
 492         }
 493
 494         if ( !NT_STATUS_IS_OK(nss_status) ) {
 495                 nss_status = smb_register_idmap_nss(SMB_NSS_INFO_INTERFACE_VERSION,
 496                                                     "hash", &hash_nss_methods);
 497                 if ( !NT_STATUS_IS_OK(nss_status) ) {
 498                         DEBUG(0,("Failed to register hash idmap nss plugin.\n"));
 499                         return nss_status;
 500                 }
 501         }
 502
 503         return NT_STATUS_OK;
 504 }