source4/dsdb/samdb/ldb_modules/objectclass_attrs.c

   1 /*
   2    ldb database library
   3
   4    Copyright (C) Simo Sorce  2006-2008
   5    Copyright (C) Andrew Bartlett <abartlet@samba.org> 2005-2009
   6    Copyright (C) Stefan Metzmacher 2009
   7    Copyright (C) Matthias Dieter Wallnöfer 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    You should have received a copy of the GNU Lesser General Public
  20    License along with this library; if not, see <http://www.gnu.org/licenses/>.
  21 */
  22
  23 /*
  24  *  Name: ldb
  25  *
  26  *  Component: objectclass attribute checking module
  27  *
  28  *  Description: this checks the attributes on a directory entry (if they're
  29  *    allowed, if the syntax is correct, if mandatory ones are missing,
  30  *    denies the deletion of mandatory ones...). The module contains portions
  31  *    of the "objectclass" and the "validate_update" LDB module.
  32  *
  33  *  Author: Matthias Dieter Wallnöfer
  34  */
  35
  36 #include "includes.h"
  37 #include "ldb_module.h"
  38 #include "dsdb/samdb/samdb.h"
  39
  40 struct oc_context {
  41
  42         struct ldb_module *module;
  43         struct ldb_request *req;
  44         const struct dsdb_schema *schema;
  45
  46         struct ldb_message *msg;
  47
  48         struct ldb_reply *search_res;
  49         struct ldb_reply *mod_ares;
  50 };
  51
  52 static struct oc_context *oc_init_context(struct ldb_module *module,
  53                                           struct ldb_request *req)
  54 {
  55         struct ldb_context *ldb;
  56         struct oc_context *ac;
  57
  58         ldb = ldb_module_get_ctx(module);
  59
  60         ac = talloc_zero(req, struct oc_context);
  61         if (ac == NULL) {
  62                 ldb_oom(ldb);
  63                 return NULL;
  64         }
  65
  66         ac->module = module;
  67         ac->req = req;
  68         ac->schema = dsdb_get_schema(ldb, ac);
  69
  70         return ac;
  71 }
  72
  73 static int oc_op_callback(struct ldb_request *req, struct ldb_reply *ares);
  74
  75 /*
  76  * Checks the correctness of the "dSHeuristics" attribute as described in both
  77  * MS-ADTS 7.1.1.2.4.1.2 dSHeuristics and MS-ADTS 3.1.1.5.3.2 Constraints
  78  */
  79 static int oc_validate_dsheuristics(struct ldb_message_element *el)
  80 {
  81         if (el->num_values > 0) {
  82                 if ((el->values[0].length >= DS_HR_NINETIETH_CHAR) &&
  83                     (el->values[0].data[DS_HR_NINETIETH_CHAR-1] != '9')) {
  84                         return LDB_ERR_CONSTRAINT_VIOLATION;
  85                 }
  86                 if ((el->values[0].length >= DS_HR_EIGHTIETH_CHAR) &&
  87                     (el->values[0].data[DS_HR_EIGHTIETH_CHAR-1] != '8')) {
  88                         return LDB_ERR_CONSTRAINT_VIOLATION;
  89                 }
  90                 if ((el->values[0].length >= DS_HR_SEVENTIETH_CHAR) &&
  91                     (el->values[0].data[DS_HR_SEVENTIETH_CHAR-1] != '7')) {
  92                         return LDB_ERR_CONSTRAINT_VIOLATION;
  93                 }
  94                 if ((el->values[0].length >= DS_HR_SIXTIETH_CHAR) &&
  95                     (el->values[0].data[DS_HR_SIXTIETH_CHAR-1] != '6')) {
  96                         return LDB_ERR_CONSTRAINT_VIOLATION;
  97                 }
  98                 if ((el->values[0].length >= DS_HR_FIFTIETH_CHAR) &&
  99                     (el->values[0].data[DS_HR_FIFTIETH_CHAR-1] != '5')) {
 100                         return LDB_ERR_CONSTRAINT_VIOLATION;
 101                 }
 102                 if ((el->values[0].length >= DS_HR_FOURTIETH_CHAR) &&
 103                     (el->values[0].data[DS_HR_FOURTIETH_CHAR-1] != '4')) {
 104                         return LDB_ERR_CONSTRAINT_VIOLATION;
 105                 }
 106                 if ((el->values[0].length >= DS_HR_THIRTIETH_CHAR) &&
 107                     (el->values[0].data[DS_HR_THIRTIETH_CHAR-1] != '3')) {
 108                         return LDB_ERR_CONSTRAINT_VIOLATION;
 109                 }
 110                 if ((el->values[0].length >= DS_HR_TWENTIETH_CHAR) &&
 111                     (el->values[0].data[DS_HR_TWENTIETH_CHAR-1] != '2')) {
 112                         return LDB_ERR_CONSTRAINT_VIOLATION;
 113                 }
 114                 if ((el->values[0].length >= DS_HR_TENTH_CHAR) &&
 115                     (el->values[0].data[DS_HR_TENTH_CHAR-1] != '1')) {
 116                         return LDB_ERR_CONSTRAINT_VIOLATION;
 117                 }
 118         }
 119
 120         return LDB_SUCCESS;
 121 }
 122
 123 /*
 124   auto normalise values on input
 125  */
 126 static int oc_auto_normalise(struct ldb_context *ldb, const struct dsdb_attribute *attr,
 127                              struct ldb_message *msg, struct ldb_message_element *el)
 128 {
 129         int i;
 130         bool values_copied = false;
 131
 132         for (i=0; i<el->num_values; i++) {
 133                 struct ldb_val v;
 134                 int ret;
 135                 ret = attr->ldb_schema_attribute->syntax->canonicalise_fn(ldb, el->values, &el->values[i], &v);
 136                 if (ret != LDB_SUCCESS) {
 137                         return ret;
 138                 }
 139                 if (data_blob_cmp(&v, &el->values[i]) == 0) {
 140                         /* no need to replace it */
 141                         talloc_free(v.data);
 142                         continue;
 143                 }
 144
 145                 /* we need to copy the values array on the first change */
 146                 if (!values_copied) {
 147                         struct ldb_val *v2;
 148                         v2 = talloc_array(msg->elements, struct ldb_val, el->num_values);
 149                         if (v2 == NULL) {
 150                                 return ldb_oom(ldb);
 151                         }
 152                         memcpy(v2, el->values, sizeof(struct ldb_val) * el->num_values);
 153                         el->values = v2;
 154                         values_copied = true;
 155                 }
 156
 157                 el->values[i] = v;
 158         }
 159         return LDB_SUCCESS;
 160 }
 161
 162 static int attr_handler(struct oc_context *ac)
 163 {
 164         struct ldb_context *ldb;
 165         struct ldb_message *msg;
 166         struct ldb_request *child_req;
 167         const struct dsdb_attribute *attr;
 168         unsigned int i;
 169         int ret;
 170         WERROR werr;
 171         struct dsdb_syntax_ctx syntax_ctx;
 172
 173         ldb = ldb_module_get_ctx(ac->module);
 174
 175         if (ac->req->operation == LDB_ADD) {
 176                 msg = ldb_msg_copy_shallow(ac, ac->req->op.add.message);
 177         } else {
 178                 msg = ldb_msg_copy_shallow(ac, ac->req->op.mod.message);
 179         }
 180         if (msg == NULL) {
 181                 return ldb_oom(ldb);
 182         }
 183         ac->msg = msg;
 184
 185         /* initialize syntax checking context */
 186         dsdb_syntax_ctx_init(&syntax_ctx, ldb, ac->schema);
 187
 188         /* Check if attributes exist in the schema, if the values match,
 189          * if they're not operational and fix the names to the match the schema
 190          * case */
 191         for (i = 0; i < msg->num_elements; i++) {
 192                 attr = dsdb_attribute_by_lDAPDisplayName(ac->schema,
 193                                                          msg->elements[i].name);
 194                 if (attr == NULL) {
 195                         if (ldb_request_get_control(ac->req, LDB_CONTROL_RELAX_OID) &&
 196                             ac->req->operation != LDB_ADD) {
 197                                 /* we allow this for dbcheck to fix
 198                                    broken attributes */
 199                                 goto no_attribute;
 200                         }
 201                         ldb_asprintf_errstring(ldb, "objectclass_attrs: attribute '%s' on entry '%s' was not found in the schema!",
 202                                                msg->elements[i].name,
 203                                                ldb_dn_get_linearized(msg->dn));
 204                         return LDB_ERR_NO_SUCH_ATTRIBUTE;
 205                 }
 206
 207                 if ((attr->linkID & 1) == 1 &&
 208                     !ldb_request_get_control(ac->req, LDB_CONTROL_RELAX_OID) &&
 209                     !ldb_request_get_control(ac->req, DSDB_CONTROL_DBCHECK)) {
 210                         /* Odd is for the target.  Illegal to modify */
 211                         ldb_asprintf_errstring(ldb,
 212                                                "objectclass_attrs: attribute '%s' on entry '%s' must not be modified directly, it is a linked attribute",
 213                                                msg->elements[i].name,
 214                                                ldb_dn_get_linearized(msg->dn));
 215                         return LDB_ERR_UNWILLING_TO_PERFORM;
 216                 }
 217
 218                 if (!(msg->elements[i].flags & LDB_FLAG_INTERNAL_DISABLE_VALIDATION)) {
 219                         werr = attr->syntax->validate_ldb(&syntax_ctx, attr,
 220                                                           &msg->elements[i]);
 221                         if (!W_ERROR_IS_OK(werr) &&
 222                             !ldb_request_get_control(ac->req, LDB_CONTROL_RELAX_OID)) {
 223                                 ldb_asprintf_errstring(ldb, "objectclass_attrs: attribute '%s' on entry '%s' contains at least one invalid value!",
 224                                                        msg->elements[i].name,
 225                                                        ldb_dn_get_linearized(msg->dn));
 226                                 return LDB_ERR_INVALID_ATTRIBUTE_SYNTAX;
 227                         }
 228                 }
 229
 230                 if ((attr->systemFlags & DS_FLAG_ATTR_IS_CONSTRUCTED) != 0) {
 231                         ldb_asprintf_errstring(ldb, "objectclass_attrs: attribute '%s' on entry '%s' is constructed!",
 232                                                msg->elements[i].name,
 233                                                ldb_dn_get_linearized(msg->dn));
 234                         if (ac->req->operation == LDB_ADD) {
 235                                 return LDB_ERR_UNDEFINED_ATTRIBUTE_TYPE;
 236                         } else {
 237                                 return LDB_ERR_CONSTRAINT_VIOLATION;
 238                         }
 239                 }
 240
 241                 /* "dSHeuristics" syntax check */
 242                 if (ldb_attr_cmp(attr->lDAPDisplayName, "dSHeuristics") == 0) {
 243                         ret = oc_validate_dsheuristics(&(msg->elements[i]));
 244                         if (ret != LDB_SUCCESS) {
 245                                 return ret;
 246                         }
 247                 }
 248
 249                 /* auto normalise some attribute values */
 250                 if (attr->syntax->auto_normalise) {
 251                         ret = oc_auto_normalise(ldb, attr, msg, &msg->elements[i]);
 252                         if (ret != LDB_SUCCESS) {
 253                                 return ret;
 254                         }
 255                 }
 256
 257                 /* Substitute the attribute name to match in case */
 258                 msg->elements[i].name = attr->lDAPDisplayName;
 259         }
 260
 261 no_attribute:
 262         if (ac->req->operation == LDB_ADD) {
 263                 ret = ldb_build_add_req(&child_req, ldb, ac,
 264                                         msg, ac->req->controls,
 265                                         ac, oc_op_callback, ac->req);
 266                 LDB_REQ_SET_LOCATION(child_req);
 267         } else {
 268                 ret = ldb_build_mod_req(&child_req, ldb, ac,
 269                                         msg, ac->req->controls,
 270                                         ac, oc_op_callback, ac->req);
 271                 LDB_REQ_SET_LOCATION(child_req);
 272         }
 273         if (ret != LDB_SUCCESS) {
 274                 return ret;
 275         }
 276
 277         return ldb_next_request(ac->module, child_req);
 278 }
 279
 280 /*
 281   these are attributes which are left over from old ways of doing
 282   things in ldb, and are harmless
 283  */
 284 static const char *harmless_attrs[] = { "parentGUID", NULL };
 285
 286 static int attr_handler2(struct oc_context *ac)
 287 {
 288         struct ldb_context *ldb;
 289         struct ldb_message_element *oc_element;
 290         struct ldb_message *msg;
 291         const char **must_contain, **may_contain, **found_must_contain;
 292         /* There exists a hardcoded delete-protected attributes list in AD */
 293         const char *del_prot_attributes[] = { "nTSecurityDescriptor",
 294                 "objectSid", "sAMAccountType", "sAMAccountName", "groupType",
 295                 "primaryGroupID", "userAccountControl", "accountExpires",
 296                 "badPasswordTime", "badPwdCount", "codePage", "countryCode",
 297                 "lastLogoff", "lastLogon", "logonCount", "pwdLastSet", NULL },
 298                 **l;
 299         const struct dsdb_attribute *attr;
 300         unsigned int i;
 301         bool found;
 302
 303         ldb = ldb_module_get_ctx(ac->module);
 304
 305         if (ac->search_res == NULL) {
 306                 return ldb_operr(ldb);
 307         }
 308
 309         /* We rely here on the preceeding "objectclass" LDB module which did
 310          * already fix up the objectclass list (inheritance, order...). */
 311         oc_element = ldb_msg_find_element(ac->search_res->message,
 312                                           "objectClass");
 313         if (oc_element == NULL) {
 314                 return ldb_operr(ldb);
 315         }
 316
 317         /* LSA-specific object classes are not allowed to be created over LDAP,
 318          * so we need to tell if this connection is internal (trusted) or not
 319          * (untrusted).
 320          *
 321          * Hongwei Sun from Microsoft explains:
 322          * The constraint in 3.1.1.5.2.2 MS-ADTS means that LSA objects cannot
 323          * be added or modified through the LDAP interface, instead they can
 324          * only be handled through LSA Policy API.  This is also explained in
 325          * 7.1.6.9.7 MS-ADTS as follows:
 326          * "Despite being replicated normally between peer DCs in a domain,
 327          * the process of creating or manipulating TDOs is specifically
 328          * restricted to the LSA Policy APIs, as detailed in [MS-LSAD] section
 329          * 3.1.1.5. Unlike other objects in the DS, TDOs may not be created or
 330          *  manipulated by client machines over the LDAPv3 transport."
 331          */
 332         if (ldb_req_is_untrusted(ac->req)) {
 333                 for (i = 0; i < oc_element->num_values; i++) {
 334                         if ((strcmp((char *)oc_element->values[i].data,
 335                                     "secret") == 0) ||
 336                             (strcmp((char *)oc_element->values[i].data,
 337                                     "trustedDomain") == 0)) {
 338                                 ldb_asprintf_errstring(ldb, "objectclass_attrs: LSA objectclasses (entry '%s') cannot be created or changed over LDAP!",
 339                                                        ldb_dn_get_linearized(ac->search_res->message->dn));
 340                                 return LDB_ERR_UNWILLING_TO_PERFORM;
 341                         }
 342                 }
 343         }
 344
 345         must_contain = dsdb_full_attribute_list(ac, ac->schema, oc_element,
 346                                                 DSDB_SCHEMA_ALL_MUST);
 347         may_contain =  dsdb_full_attribute_list(ac, ac->schema, oc_element,
 348                                                 DSDB_SCHEMA_ALL_MAY);
 349         found_must_contain = const_str_list(str_list_copy(ac, must_contain));
 350         if ((must_contain == NULL) || (may_contain == NULL)
 351             || (found_must_contain == NULL)) {
 352                 return ldb_operr(ldb);
 353         }
 354
 355         /* Check the delete-protected attributes list */
 356         msg = ac->search_res->message;
 357         for (l = del_prot_attributes; *l != NULL; l++) {
 358                 struct ldb_message_element *el;
 359
 360                 el = ldb_msg_find_element(ac->msg, *l);
 361                 if (el == NULL) {
 362                         /*
 363                          * It was not specified in the add or modify,
 364                          * so it doesn't need to be in the stored record
 365                          */
 366                         continue;
 367                 }
 368
 369                 found = str_list_check_ci(must_contain, *l);
 370                 if (!found) {
 371                         found = str_list_check_ci(may_contain, *l);
 372                 }
 373                 if (found && (ldb_msg_find_element(msg, *l) == NULL)) {
 374                         ldb_asprintf_errstring(ldb, "objectclass_attrs: delete protected attribute '%s' on entry '%s' missing!",
 375                                                *l,
 376                                                ldb_dn_get_linearized(msg->dn));
 377                         return LDB_ERR_UNWILLING_TO_PERFORM;
 378                 }
 379         }
 380
 381         /* Check if all specified attributes are valid in the given
 382          * objectclasses and if they meet additional schema restrictions. */
 383         for (i = 0; i < msg->num_elements; i++) {
 384                 attr = dsdb_attribute_by_lDAPDisplayName(ac->schema,
 385                                                          msg->elements[i].name);
 386                 if (attr == NULL) {
 387                         if (ldb_request_get_control(ac->req, LDB_CONTROL_RELAX_OID)) {
 388                                 /* allow this to make it possible for dbcheck
 389                                    to remove bad attributes */
 390                                 continue;
 391                         }
 392                         return ldb_operr(ldb);
 393                 }
 394
 395                 /* We can use "str_list_check" with "strcmp" here since the
 396                  * attribute information from the schema are always equal
 397                  * up-down-cased. */
 398                 found = str_list_check(must_contain, attr->lDAPDisplayName);
 399                 if (found) {
 400                         str_list_remove(found_must_contain, attr->lDAPDisplayName);
 401                 } else {
 402                         found = str_list_check(may_contain, attr->lDAPDisplayName);
 403                 }
 404                 if (!found) {
 405                         found = str_list_check(harmless_attrs, attr->lDAPDisplayName);
 406                 }
 407                 if (!found) {
 408                         ldb_asprintf_errstring(ldb, "objectclass_attrs: attribute '%s' on entry '%s' does not exist in the specified objectclasses!",
 409                                                msg->elements[i].name,
 410                                                ldb_dn_get_linearized(msg->dn));
 411                         return LDB_ERR_OBJECT_CLASS_VIOLATION;
 412                 }
 413         }
 414
 415         if (found_must_contain[0] != NULL &&
 416             ldb_msg_check_string_attribute(msg, "isDeleted", "TRUE") == 0) {
 417                 ldb_asprintf_errstring(ldb, "objectclass_attrs: at least one mandatory attribute ('%s') on entry '%s' wasn't specified!",
 418                                        found_must_contain[0],
 419                                        ldb_dn_get_linearized(msg->dn));
 420                 return LDB_ERR_OBJECT_CLASS_VIOLATION;
 421         }
 422
 423         return ldb_module_done(ac->req, ac->mod_ares->controls,
 424                                ac->mod_ares->response, LDB_SUCCESS);
 425 }
 426
 427 static int get_search_callback(struct ldb_request *req, struct ldb_reply *ares)
 428 {
 429         struct ldb_context *ldb;
 430         struct oc_context *ac;
 431         int ret;
 432
 433         ac = talloc_get_type(req->context, struct oc_context);
 434         ldb = ldb_module_get_ctx(ac->module);
 435
 436         if (!ares) {
 437                 return ldb_module_done(ac->req, NULL, NULL,
 438                                        LDB_ERR_OPERATIONS_ERROR);
 439         }
 440         if (ares->error != LDB_SUCCESS) {
 441                 return ldb_module_done(ac->req, ares->controls,
 442                                        ares->response, ares->error);
 443         }
 444
 445         ldb_reset_err_string(ldb);
 446
 447         switch (ares->type) {
 448         case LDB_REPLY_ENTRY:
 449                 if (ac->search_res != NULL) {
 450                         ldb_set_errstring(ldb, "Too many results");
 451                         talloc_free(ares);
 452                         return ldb_module_done(ac->req, NULL, NULL,
 453                                                LDB_ERR_OPERATIONS_ERROR);
 454                 }
 455
 456                 ac->search_res = talloc_steal(ac, ares);
 457                 break;
 458
 459         case LDB_REPLY_REFERRAL:
 460                 /* ignore */
 461                 talloc_free(ares);
 462                 break;
 463
 464         case LDB_REPLY_DONE:
 465                 talloc_free(ares);
 466                 ret = attr_handler2(ac);
 467                 if (ret != LDB_SUCCESS) {
 468                         return ldb_module_done(ac->req, NULL, NULL, ret);
 469                 }
 470                 break;
 471         }
 472
 473         return LDB_SUCCESS;
 474 }
 475
 476 static int oc_op_callback(struct ldb_request *req, struct ldb_reply *ares)
 477 {
 478         struct oc_context *ac;
 479         struct ldb_context *ldb;
 480         struct ldb_request *search_req;
 481         struct ldb_dn *base_dn;
 482         int ret;
 483
 484         ac = talloc_get_type(req->context, struct oc_context);
 485         ldb = ldb_module_get_ctx(ac->module);
 486
 487         if (!ares) {
 488                 return ldb_module_done(ac->req, NULL, NULL,
 489                                        LDB_ERR_OPERATIONS_ERROR);
 490         }
 491
 492         if (ares->type == LDB_REPLY_REFERRAL) {
 493                 return ldb_module_send_referral(ac->req, ares->referral);
 494         }
 495
 496         if (ares->error != LDB_SUCCESS) {
 497                 return ldb_module_done(ac->req, ares->controls, ares->response,
 498                                        ares->error);
 499         }
 500
 501         if (ares->type != LDB_REPLY_DONE) {
 502                 talloc_free(ares);
 503                 return ldb_module_done(ac->req, NULL, NULL,
 504                                        LDB_ERR_OPERATIONS_ERROR);
 505         }
 506
 507         ac->search_res = NULL;
 508         ac->mod_ares = talloc_steal(ac, ares);
 509
 510         /* This looks up all attributes of our just added/modified entry */
 511         base_dn = ac->req->operation == LDB_ADD ? ac->req->op.add.message->dn
 512                 : ac->req->op.mod.message->dn;
 513         ret = ldb_build_search_req(&search_req, ldb, ac, base_dn,
 514                                    LDB_SCOPE_BASE, "(objectClass=*)",
 515                                    NULL, NULL, ac,
 516                                    get_search_callback, ac->req);
 517         LDB_REQ_SET_LOCATION(search_req);
 518         if (ret != LDB_SUCCESS) {
 519                 return ldb_module_done(ac->req, NULL, NULL, ret);
 520         }
 521
 522         ret = ldb_request_add_control(search_req, LDB_CONTROL_SHOW_RECYCLED_OID,
 523                                       true, NULL);
 524         if (ret != LDB_SUCCESS) {
 525                 return ldb_module_done(ac->req, NULL, NULL, ret);
 526         }
 527
 528         ret = ldb_next_request(ac->module, search_req);
 529         if (ret != LDB_SUCCESS) {
 530                 return ldb_module_done(ac->req, NULL, NULL, ret);
 531         }
 532
 533         /* "ldb_module_done" isn't called here since we need to do additional
 534          * checks. It is called at the end of "attr_handler2". */
 535         return LDB_SUCCESS;
 536 }
 537
 538 static int objectclass_attrs_add(struct ldb_module *module,
 539                                  struct ldb_request *req)
 540 {
 541         struct ldb_context *ldb;
 542         struct oc_context *ac;
 543
 544         ldb = ldb_module_get_ctx(module);
 545
 546         ldb_debug(ldb, LDB_DEBUG_TRACE, "objectclass_attrs_add\n");
 547
 548         /* do not manipulate our control entries */
 549         if (ldb_dn_is_special(req->op.add.message->dn)) {
 550                 return ldb_next_request(module, req);
 551         }
 552
 553         ac = oc_init_context(module, req);
 554         if (ac == NULL) {
 555                 return ldb_operr(ldb);
 556         }
 557
 558         /* without schema, there isn't much to do here */
 559         if (ac->schema == NULL) {
 560                 talloc_free(ac);
 561                 return ldb_next_request(module, req);
 562         }
 563
 564         return attr_handler(ac);
 565 }
 566
 567 static int objectclass_attrs_modify(struct ldb_module *module,
 568                                     struct ldb_request *req)
 569 {
 570         struct ldb_context *ldb;
 571         struct oc_context *ac;
 572
 573         ldb = ldb_module_get_ctx(module);
 574
 575         ldb_debug(ldb, LDB_DEBUG_TRACE, "objectclass_attrs_modify\n");
 576
 577         /* do not manipulate our control entries */
 578         if (ldb_dn_is_special(req->op.mod.message->dn)) {
 579                 return ldb_next_request(module, req);
 580         }
 581
 582         ac = oc_init_context(module, req);
 583         if (ac == NULL) {
 584                 return ldb_operr(ldb);
 585         }
 586
 587         /* without schema, there isn't much to do here */
 588         if (ac->schema == NULL) {
 589                 talloc_free(ac);
 590                 return ldb_next_request(module, req);
 591         }
 592
 593         return attr_handler(ac);
 594 }
 595
 596 static const struct ldb_module_ops ldb_objectclass_attrs_module_ops = {
 597         .name              = "objectclass_attrs",
 598         .add               = objectclass_attrs_add,
 599         .modify            = objectclass_attrs_modify
 600 };
 601
 602 int ldb_objectclass_attrs_module_init(const char *version)
 603 {
 604         LDB_MODULE_CHECK_VERSION(version);
 605         return ldb_register_module(&ldb_objectclass_attrs_module_ops);
 606 }