source/groupdb/mapping_ldb.c

   1 /*
   2  *  Unix SMB/CIFS implementation.
   3  *
   4  *  group mapping code on top of ldb
   5  *
   6  *  Copyright (C) Andrew Tridgell              2006
   7  *
   8  * based on tdb group mapping code from groupdb/mapping.c
   9  *
  10  *  This program is free software; you can redistribute it and/or modify
  11  *  it under the terms of the GNU General Public License as published by
  12  *  the Free Software Foundation; either version 3 of the License, or
  13  *  (at your option) any later version.
  14  *
  15  *  This program is distributed in the hope that it will be useful,
  16  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  17  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18  *  GNU General Public License for more details.
  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 "groupdb/mapping.h"
  26 #include "lib/ldb/include/includes.h"
  27 #include "lib/ldb/include/ldb_errors.h"
  28
  29 static struct ldb_context *ldb;
  30
  31 static bool mapping_upgrade(const char *tdb_path);
  32
  33 /*
  34   connect to the group mapping ldb
  35 */
  36 static bool init_group_mapping(void)
  37 {
  38         bool existed;
  39         const char *init_ldif[] =
  40                 { "dn: @ATTRIBUTES\n" \
  41                   "ntName: CASE_INSENSITIVE\n" \
  42                   "\n",
  43                   "dn: @INDEXLIST\n" \
  44                   "@IDXATTR: gidNumber\n" \
  45                   "@IDXATTR: ntName\n" \
  46                   "@IDXATTR: member\n" };
  47         const char *db_path, *tdb_path;
  48         int ret;
  49         int flags = 0;
  50
  51         if (ldb != NULL) {
  52                 return True;
  53         }
  54
  55         /* this is needed as Samba3 doesn't have this globally yet */
  56         ldb_global_init();
  57
  58         db_path = state_path("group_mapping.ldb");
  59
  60         ldb = ldb_init(NULL);
  61         if (ldb == NULL) goto failed;
  62
  63         existed = file_exist(db_path, NULL);
  64
  65         if (lp_parm_bool(-1, "groupmap", "nosync", False)) {
  66                 flags |= LDB_FLG_NOSYNC;
  67         }
  68
  69         if (!lp_use_mmap()) {
  70                 flags |= LDB_FLG_NOMMAP;
  71         }
  72
  73         ret = ldb_connect(ldb, db_path, flags, NULL);
  74         if (ret != LDB_SUCCESS) {
  75                 goto failed;
  76         }
  77
  78         if (!existed) {
  79                 /* initialise the ldb with an index */
  80                 struct ldb_ldif *ldif;
  81                 int i;
  82                 for (i=0;i<ARRAY_SIZE(init_ldif);i++) {
  83                         ldif = ldb_ldif_read_string(ldb, &init_ldif[i]);
  84                         if (ldif == NULL) goto failed;
  85                         ret = ldb_add(ldb, ldif->msg);
  86                         talloc_free(ldif);
  87                         if (ret == -1) goto failed;
  88                 }
  89         }
  90
  91         /* possibly upgrade */
  92         tdb_path = state_path("group_mapping.tdb");
  93         if (file_exist(tdb_path, NULL) && !mapping_upgrade(tdb_path)) {
  94                 unlink(state_path("group_mapping.ldb"));
  95                 goto failed;
  96         }
  97
  98         return True;
  99
 100 failed:
 101         DEBUG(0,("Failed to open group mapping ldb '%s' - '%s'\n",
 102                  db_path, ldb?ldb_errstring(ldb):strerror(errno)));
 103         talloc_free(ldb);
 104         ldb = NULL;
 105         return False;
 106 }
 107
 108
 109 /*
 110   form the DN for a mapping entry from a SID
 111  */
 112 static struct ldb_dn *mapping_dn(TALLOC_CTX *mem_ctx, const DOM_SID *sid)
 113 {
 114         fstring string_sid;
 115         uint32_t rid;
 116         DOM_SID domsid;
 117
 118         sid_copy(&domsid, sid);
 119         if (!sid_split_rid(&domsid, &rid)) {
 120                 return NULL;
 121         }
 122         if (!sid_to_fstring(string_sid, &domsid)) {
 123                 return NULL;
 124         }
 125         /* we split by domain and rid so we can do a subtree search
 126            when we only want one domain */
 127         return ldb_dn_string_compose(mem_ctx, NULL, "rid=%u,domain=%s",
 128                                      rid, string_sid);
 129 }
 130
 131 /*
 132   add a group mapping entry
 133  */
 134 static bool add_mapping_entry(GROUP_MAP *map, int flag)
 135 {
 136         struct ldb_message *msg;
 137         int ret, i;
 138         fstring string_sid;
 139
 140         msg = ldb_msg_new(ldb);
 141         if (msg == NULL) {
 142                 return False;
 143         }
 144
 145         msg->dn = mapping_dn(msg, &map->sid);
 146         if (msg->dn == NULL) {
 147                 goto failed;
 148         }
 149
 150         if (ldb_msg_add_string(msg, "objectClass", "groupMap") != LDB_SUCCESS ||
 151             ldb_msg_add_string(msg, "sid",
 152                                sid_to_fstring(string_sid, &map->sid)) != LDB_SUCCESS ||
 153             ldb_msg_add_fmt(msg, "gidNumber", "%u", (unsigned)map->gid) != LDB_SUCCESS ||
 154             ldb_msg_add_fmt(msg, "sidNameUse", "%u", (unsigned)map->sid_name_use) != LDB_SUCCESS ||
 155             ldb_msg_add_string(msg, "comment", map->comment) != LDB_SUCCESS ||
 156             ldb_msg_add_string(msg, "ntName", map->nt_name) != LDB_SUCCESS) {
 157                 goto failed;
 158         }
 159
 160         ret = ldb_add(ldb, msg);
 161
 162         /* if it exists we update it. This is a hangover from the semantics the
 163            tdb backend had */
 164         if (ret == LDB_ERR_ENTRY_ALREADY_EXISTS) {
 165                 for (i=0;i<msg->num_elements;i++) {
 166                         msg->elements[i].flags = LDB_FLAG_MOD_REPLACE;
 167                 }
 168                 ret = ldb_modify(ldb, msg);
 169         }
 170
 171         talloc_free(msg);
 172
 173         return ret == LDB_SUCCESS;
 174
 175 failed:
 176         talloc_free(msg);
 177         return False;
 178 }
 179
 180 /*
 181   unpack a ldb message into a GROUP_MAP structure
 182 */
 183 static bool msg_to_group_map(struct ldb_message *msg, GROUP_MAP *map)
 184 {
 185         const char *sidstr;
 186
 187         map->gid          = ldb_msg_find_attr_as_int(msg, "gidNumber", -1);
 188         map->sid_name_use = ldb_msg_find_attr_as_int(msg, "sidNameUse", -1);
 189         fstrcpy(map->nt_name, ldb_msg_find_attr_as_string(msg, "ntName", NULL));
 190         fstrcpy(map->comment, ldb_msg_find_attr_as_string(msg, "comment", NULL));
 191         sidstr = ldb_msg_find_attr_as_string(msg, "sid", NULL);
 192
 193         if (!string_to_sid(&map->sid, sidstr) ||
 194             map->gid == (gid_t)-1 ||
 195             map->sid_name_use == (enum lsa_SidType)-1) {
 196                 DEBUG(0,("Unable to unpack group mapping\n"));
 197                 return False;
 198         }
 199
 200         return True;
 201 }
 202
 203 /*
 204  return a group map entry for a given sid
 205 */
 206 static bool get_group_map_from_sid(DOM_SID sid, GROUP_MAP *map)
 207 {
 208         int ret;
 209         struct ldb_dn *dn;
 210         struct ldb_result *res=NULL;
 211
 212         dn = mapping_dn(ldb, &sid);
 213         if (dn == NULL) goto failed;
 214
 215         ret = ldb_search(ldb, dn, LDB_SCOPE_BASE, NULL, NULL, &res);
 216         talloc_steal(dn, res);
 217         if (ret != LDB_SUCCESS || res->count != 1) {
 218                 goto failed;
 219         }
 220
 221         if (!msg_to_group_map(res->msgs[0], map)) goto failed;
 222
 223         talloc_free(dn);
 224         return True;
 225
 226 failed:
 227         talloc_free(dn);
 228         return False;
 229 }
 230
 231 /*
 232  return a group map entry for a given gid
 233 */
 234 static bool get_group_map_from_gid(gid_t gid, GROUP_MAP *map)
 235 {
 236         int ret;
 237         char *expr;
 238         struct ldb_result *res=NULL;
 239
 240         expr = talloc_asprintf(ldb, "(&(gidNumber=%u)(objectClass=groupMap))",
 241                                (unsigned)gid);
 242         if (expr == NULL) goto failed;
 243
 244         ret = ldb_search(ldb, NULL, LDB_SCOPE_SUBTREE, expr, NULL, &res);
 245         talloc_steal(expr, res);
 246         if (ret != LDB_SUCCESS || res->count != 1) goto failed;
 247
 248         if (!msg_to_group_map(res->msgs[0], map)) goto failed;
 249
 250         talloc_free(expr);
 251         return True;
 252
 253 failed:
 254         talloc_free(expr);
 255         return False;
 256 }
 257
 258 /*
 259   Return the sid and the type of the unix group.
 260 */
 261 static bool get_group_map_from_ntname(const char *name, GROUP_MAP *map)
 262 {
 263         int ret;
 264         char *expr;
 265         struct ldb_result *res=NULL;
 266
 267         expr = talloc_asprintf(ldb, "(&(ntName=%s)(objectClass=groupMap))", name);
 268         if (expr == NULL) goto failed;
 269
 270         ret = ldb_search(ldb, NULL, LDB_SCOPE_SUBTREE, expr, NULL, &res);
 271         talloc_steal(expr, res);
 272         if (ret != LDB_SUCCESS || res->count != 1) goto failed;
 273
 274         if (!msg_to_group_map(res->msgs[0], map)) goto failed;
 275
 276         talloc_free(expr);
 277         return True;
 278
 279 failed:
 280         talloc_free(expr);
 281         return False;
 282 }
 283
 284 /*
 285  Remove a group mapping entry.
 286 */
 287 static bool group_map_remove(const DOM_SID *sid)
 288 {
 289         struct ldb_dn *dn;
 290         int ret;
 291
 292         dn = mapping_dn(ldb, sid);
 293         if (dn == NULL) {
 294                 return False;
 295         }
 296         ret = ldb_delete(ldb, dn);
 297         talloc_free(dn);
 298
 299         return ret == LDB_SUCCESS;
 300 }
 301
 302
 303 /*
 304   Enumerate the group mappings for a domain
 305 */
 306 static bool enum_group_mapping(const DOM_SID *domsid, enum lsa_SidType sid_name_use,
 307                                GROUP_MAP **pp_rmap,
 308                                size_t *p_num_entries, bool unix_only)
 309 {
 310         int i, ret;
 311         char *expr;
 312         fstring name;
 313         struct ldb_result *res;
 314         struct ldb_dn *basedn=NULL;
 315         TALLOC_CTX *tmp_ctx;
 316
 317         tmp_ctx = talloc_new(ldb);
 318         if (tmp_ctx == NULL) goto failed;
 319
 320         if (sid_name_use == SID_NAME_UNKNOWN) {
 321                 expr = talloc_asprintf(tmp_ctx, "(&(objectClass=groupMap))");
 322         } else {
 323                 expr = talloc_asprintf(tmp_ctx, "(&(sidNameUse=%u)(objectClass=groupMap))",
 324                                        sid_name_use);
 325         }
 326         if (expr == NULL) goto failed;
 327
 328         /* we do a subtree search on the domain */
 329         if (domsid != NULL) {
 330                 sid_to_fstring(name, domsid);
 331                 basedn = ldb_dn_string_compose(tmp_ctx, NULL, "domain=%s", name);
 332                 if (basedn == NULL) goto failed;
 333         }
 334
 335         ret = ldb_search(ldb, basedn, LDB_SCOPE_SUBTREE, expr, NULL, &res);
 336         if (ret != LDB_SUCCESS) goto failed;
 337
 338         (*pp_rmap) = NULL;
 339         *p_num_entries = 0;
 340
 341         for (i=0;i<res->count;i++) {
 342                 (*pp_rmap) = SMB_REALLOC_ARRAY((*pp_rmap), GROUP_MAP,
 343                                                (*p_num_entries)+1);
 344                 if (!(*pp_rmap)) goto failed;
 345
 346                 if (!msg_to_group_map(res->msgs[i], &(*pp_rmap)[*p_num_entries])) {
 347                         goto failed;
 348                 }
 349
 350                 (*p_num_entries)++;
 351         }
 352
 353         talloc_free(tmp_ctx);
 354         return True;
 355
 356 failed:
 357         talloc_free(tmp_ctx);
 358         return False;
 359 }
 360
 361 /*
 362    This operation happens on session setup, so it should better be fast. We
 363    store a list of aliases a SID is member of hanging off MEMBEROF/SID.
 364 */
 365 static NTSTATUS one_alias_membership(const DOM_SID *member,
 366                                      DOM_SID **sids, size_t *num)
 367 {
 368         const char *attrs[] = {
 369                 "sid",
 370                 NULL
 371         };
 372         DOM_SID alias;
 373         char *expr;
 374         int ret, i;
 375         struct ldb_result *res=NULL;
 376         fstring string_sid;
 377         NTSTATUS status = NT_STATUS_INTERNAL_DB_CORRUPTION;
 378
 379         if (!sid_to_fstring(string_sid, member)) {
 380                 return NT_STATUS_INVALID_PARAMETER;
 381         }
 382
 383         expr = talloc_asprintf(ldb, "(&(member=%s)(objectClass=groupMap))",
 384                                string_sid);
 385         if (expr == NULL) goto failed;
 386
 387         ret = ldb_search(ldb, NULL, LDB_SCOPE_SUBTREE, expr, attrs, &res);
 388         talloc_steal(expr, res);
 389         if (ret != LDB_SUCCESS) {
 390                 goto failed;
 391         }
 392
 393         for (i=0;i<res->count;i++) {
 394                 struct ldb_message_element *el;
 395                 el = ldb_msg_find_element(res->msgs[i], "sid");
 396                 if (el == NULL || el->num_values != 1) {
 397                         status = NT_STATUS_INTERNAL_DB_CORRUPTION;
 398                         goto failed;
 399                 }
 400                 string_to_sid(&alias, (char *)el->values[0].data);
 401                 status = add_sid_to_array_unique(NULL, &alias, sids, num);
 402                 if (!NT_STATUS_IS_OK(status)) {
 403                         goto failed;
 404                 }
 405         }
 406
 407         talloc_free(expr);
 408         return NT_STATUS_OK;
 409
 410 failed:
 411         talloc_free(expr);
 412         return status;
 413 }
 414
 415 /*
 416   add/remove a member field
 417 */
 418 static NTSTATUS modify_aliasmem(const DOM_SID *alias, const DOM_SID *member,
 419                                 int operation)
 420 {
 421         fstring string_sid;
 422         int ret;
 423         struct ldb_message msg;
 424         struct ldb_message_element el;
 425         struct ldb_val val;
 426         TALLOC_CTX *tmp_ctx;
 427         GROUP_MAP map;
 428
 429         if (!get_group_map_from_sid(*alias, &map)) {
 430                 sid_to_fstring(string_sid, alias);
 431                 return NT_STATUS_NO_SUCH_ALIAS;
 432         }
 433
 434         if ((map.sid_name_use != SID_NAME_ALIAS) &&
 435             (map.sid_name_use != SID_NAME_WKN_GRP)) {
 436                 DEBUG(0,("sid_name_use=%d\n", map.sid_name_use));
 437                 return NT_STATUS_NO_SUCH_ALIAS;
 438         }
 439
 440         tmp_ctx = talloc_new(NULL);
 441         if (tmp_ctx == NULL) {
 442                 return NT_STATUS_NO_MEMORY;
 443         }
 444
 445         msg.dn = mapping_dn(tmp_ctx, alias);
 446         if (msg.dn == NULL) {
 447                 return NT_STATUS_NO_MEMORY;
 448         }
 449         msg.num_elements = 1;
 450         msg.elements = &el;
 451         el.flags = operation;
 452         el.name = talloc_strdup(tmp_ctx, "member");
 453         el.num_values = 1;
 454         el.values = &val;
 455         sid_to_fstring(string_sid, member);
 456         val.data = (uint8_t *)string_sid;
 457         val.length = strlen(string_sid);
 458
 459         ret = ldb_modify(ldb, &msg);
 460         talloc_free(tmp_ctx);
 461
 462         if (ret == LDB_ERR_NO_SUCH_OBJECT) {
 463                 return NT_STATUS_NO_SUCH_ALIAS;
 464         }
 465
 466         if (operation == LDB_FLAG_MOD_ADD &&
 467             ret == LDB_ERR_ATTRIBUTE_OR_VALUE_EXISTS) {
 468                 return NT_STATUS_MEMBER_IN_ALIAS;
 469         }
 470
 471         return (ret == LDB_SUCCESS ? NT_STATUS_OK : NT_STATUS_ACCESS_DENIED);
 472 }
 473
 474 static NTSTATUS add_aliasmem(const DOM_SID *alias, const DOM_SID *member)
 475 {
 476         return modify_aliasmem(alias, member, LDB_FLAG_MOD_ADD);
 477 }
 478
 479 static NTSTATUS del_aliasmem(const DOM_SID *alias, const DOM_SID *member)
 480 {
 481         return modify_aliasmem(alias, member, LDB_FLAG_MOD_DELETE);
 482 }
 483
 484
 485 /*
 486   enumerate sids that have the given alias set in member
 487 */
 488 static NTSTATUS enum_aliasmem(const DOM_SID *alias, DOM_SID **sids, size_t *num)
 489 {
 490         const char *attrs[] = {
 491                 "member",
 492                 NULL
 493         };
 494         int ret, i;
 495         NTSTATUS status = NT_STATUS_OK;
 496         struct ldb_result *res=NULL;
 497         struct ldb_dn *dn;
 498         struct ldb_message_element *el;
 499
 500         *sids = NULL;
 501         *num = 0;
 502
 503         dn = mapping_dn(ldb, alias);
 504         if (dn == NULL) {
 505                 return NT_STATUS_NO_MEMORY;
 506         }
 507
 508         ret = ldb_search(ldb, dn, LDB_SCOPE_BASE, NULL, attrs, &res);
 509         talloc_steal(dn, res);
 510         if (ret == LDB_SUCCESS && res->count == 0) {
 511                 talloc_free(dn);
 512                 return NT_STATUS_OK;
 513         }
 514         if (ret != LDB_SUCCESS) {
 515                 talloc_free(dn);
 516                 return NT_STATUS_INTERNAL_DB_CORRUPTION;
 517         }
 518
 519         el = ldb_msg_find_element(res->msgs[0], "member");
 520         if (el == NULL) {
 521                 talloc_free(dn);
 522                 return NT_STATUS_INTERNAL_DB_CORRUPTION;
 523         }
 524
 525         for (i=0;i<el->num_values;i++) {
 526                 DOM_SID sid;
 527                 string_to_sid(&sid, (const char *)el->values[i].data);
 528                 status = add_sid_to_array_unique(NULL, &sid, sids, num);
 529                 if (!NT_STATUS_IS_OK(status)) {
 530                         goto done;
 531                 }
 532         }
 533
 534 done:
 535         talloc_free(dn);
 536         return status;
 537 }
 538
 539 /*
 540   upgrade one group mapping record from the old tdb format
 541 */
 542 static int upgrade_map_record(TDB_CONTEXT *tdb_ctx, TDB_DATA key,
 543                               TDB_DATA data, void *state)
 544 {
 545         int ret;
 546         GROUP_MAP map;
 547
 548         if (strncmp((char *)key.dptr, GROUP_PREFIX,
 549                     MIN(key.dsize, strlen(GROUP_PREFIX))) != 0) {
 550                 return 0;
 551         }
 552
 553         if (!string_to_sid(&map.sid, strlen(GROUP_PREFIX) + (const char *)key.dptr)) {
 554                 DEBUG(0,("Bad sid key '%s' during upgrade\n", (const char *)key.dptr));
 555                 *(int *)state = -1;
 556                 return -1;
 557         }
 558
 559         ret = tdb_unpack(data.dptr, data.dsize, "ddff",
 560                          &map.gid, &map.sid_name_use, &map.nt_name, &map.comment);
 561         if (ret == -1) {
 562                 DEBUG(0,("Failed to unpack group map record during upgrade\n"));
 563                 *(int *)state = -1;
 564                 return -1;
 565         }
 566
 567         if (!add_mapping_entry(&map, 0)) {
 568                 DEBUG(0,("Failed to add mapping entry during upgrade\n"));
 569                 *(int *)state = -1;
 570                 return -1;
 571         }
 572
 573         return 0;
 574 }
 575
 576 /*
 577   upgrade one alias record from the old tdb format
 578 */
 579 static int upgrade_alias_record(TDB_CONTEXT *tdb_ctx, TDB_DATA key,
 580                                 TDB_DATA data, void *state)
 581 {
 582         const char *p = (const char *)data.dptr;
 583         char *string_sid;
 584         DOM_SID member;
 585         TALLOC_CTX *frame;
 586
 587         if (strncmp((char *)key.dptr, MEMBEROF_PREFIX,
 588                     MIN(key.dsize, strlen(MEMBEROF_PREFIX))) != 0) {
 589                 return 0;
 590         }
 591
 592         if (!string_to_sid(&member, strlen(MEMBEROF_PREFIX) + (const char *)key.dptr)) {
 593                 DEBUG(0,("Bad alias key %s during upgrade\n",
 594                          (const char *)key.dptr));
 595                 *(int *)state = -1;
 596         }
 597
 598         frame = talloc_stackframe();
 599         while (next_token_talloc(frame,&p, &string_sid, " ")) {
 600                 DOM_SID alias;
 601                 NTSTATUS status;
 602                 string_to_sid(&alias, string_sid);
 603                 status = add_aliasmem(&alias, &member);
 604                 if (NT_STATUS_EQUAL(status, NT_STATUS_NO_SUCH_ALIAS)) {
 605                         DEBUG(0,("Ignoring orphaned alias record '%s'\n",
 606                                  string_sid));
 607                 } else if (!NT_STATUS_IS_OK(status)) {
 608                         DEBUG(0,("Failed to add alias member during upgrade - %s\n",
 609                                  nt_errstr(status)));
 610                         *(int *)state = -1;
 611                         TALLOC_FREE(frame);
 612                         return -1;
 613                 }
 614         }
 615         TALLOC_FREE(frame);
 616         return 0;
 617 }
 618
 619 /*
 620   upgrade from a old style tdb
 621 */
 622 static bool mapping_upgrade(const char *tdb_path)
 623 {
 624         static TDB_CONTEXT *tdb;
 625         int ret, status=0;
 626
 627         tdb = tdb_open_log(tdb_path, 0, TDB_DEFAULT, O_RDWR, 0600);
 628         if (tdb == NULL) goto failed;
 629
 630         /* we have to do the map records first, as alias records may
 631            reference them */
 632         ret = tdb_traverse(tdb, upgrade_map_record, &status);
 633         if (ret == -1 || status == -1) goto failed;
 634
 635         ret = tdb_traverse(tdb, upgrade_alias_record, &status);
 636         if (ret == -1 || status == -1) goto failed;
 637
 638         if (tdb) {
 639                 tdb_close(tdb);
 640                 tdb = NULL;
 641         }
 642
 643         {
 644                 const char *old_path = tdb_path;
 645                 char *new_path = state_path("group_mapping.tdb.upgraded");
 646
 647                 if (!new_path) {
 648                         goto failed;
 649                 }
 650                 if (rename(old_path, new_path) != 0) {
 651                         DEBUG(0,("Failed to rename old group mapping database\n"));
 652                         goto failed;
 653                 }
 654         }
 655         return True;
 656
 657 failed:
 658         DEBUG(0,("Failed to upgrade group mapping database\n"));
 659         if (tdb) tdb_close(tdb);
 660         return False;
 661 }
 662
 663
 664
 665 static const struct mapping_backend ldb_backend = {
 666         .add_mapping_entry         = add_mapping_entry,
 667         .get_group_map_from_sid    = get_group_map_from_sid,
 668         .get_group_map_from_gid    = get_group_map_from_gid,
 669         .get_group_map_from_ntname = get_group_map_from_ntname,
 670         .group_map_remove          = group_map_remove,
 671         .enum_group_mapping        = enum_group_mapping,
 672         .one_alias_membership      = one_alias_membership,
 673         .add_aliasmem              = add_aliasmem,
 674         .del_aliasmem              = del_aliasmem,
 675         .enum_aliasmem             = enum_aliasmem
 676 };
 677
 678 /*
 679   initialise the ldb mapping backend
 680  */
 681 const struct mapping_backend *groupdb_ldb_init(void)
 682 {
 683         if (!init_group_mapping()) {
 684                 DEBUG(0,("Failed to initialise ldb mapping backend\n"));
 685                 return NULL;
 686         }
 687
 688         return &ldb_backend;
 689 }