source4/dsdb/samdb/ldb_modules/descriptor.c

   1    /*
   2    ldb database library
   3
   4    Copyright (C) Simo Sorce  2006-2008
   5    Copyright (C) Andrew Bartlett <abartlet@samba.org> 2005-2007
   6    Copyright (C) Nadezhda Ivanova  2009
   7
   8    This program is free software; you can redistribute it and/or modify
   9    it under the terms of the GNU General Public License as published by
  10    the Free Software Foundation; either version 3 of the License, or
  11    (at your option) any later version.
  12
  13    This program is distributed in the hope that it will be useful,
  14    but WITHOUT ANY WARRANTY; without even the implied warranty of
  15    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16    GNU General Public License for more details.
  17
  18    You should have received a copy of the GNU General Public License
  19    along with this program.  If not, see <http://www.gnu.org/licenses/>.
  20 */
  21
  22 /*
  23  *  Name: ldb
  24  *
  25  *  Component: DS Security descriptor module
  26  *
  27  *  Description:
  28  *  - Calculate the security descriptor of a newly created object
  29  *  - Perform sd recalculation on a move operation
  30  *  - Handle sd modification invariants
  31  *
  32  *  Author: Nadezhda Ivanova
  33  */
  34
  35 #include "includes.h"
  36 #include "ldb_module.h"
  37 #include "dlinklist.h"
  38 #include "dsdb/samdb/samdb.h"
  39 #include "librpc/ndr/libndr.h"
  40 #include "librpc/gen_ndr/ndr_security.h"
  41 #include "libcli/security/security.h"
  42 #include "auth/auth.h"
  43 #include "param/param.h"
  44
  45 struct descriptor_context {
  46                 struct ldb_module *module;
  47                 struct ldb_request *req;
  48                 struct ldb_reply *search_res;
  49                 int (*step_fn)(struct descriptor_context *);
  50 };
  51
  52 static struct dsdb_class * get_last_structural_class(const struct dsdb_schema *schema, struct ldb_message_element *element)
  53 {
  54         struct dsdb_class *last_class = NULL;
  55         int i;
  56         for (i = 0; i < element->num_values; i++){
  57                 if (!last_class)
  58                         last_class = dsdb_class_by_lDAPDisplayName_ldb_val(schema, &element->values[i]);
  59                 else {
  60                         struct dsdb_class *tmp_class = dsdb_class_by_lDAPDisplayName_ldb_val(schema, &element->values[i]);
  61                         if (tmp_class->subClass_order > last_class->subClass_order)
  62                                 last_class = tmp_class;
  63                 }
  64         }
  65         return last_class;
  66 }
  67
  68 struct dom_sid *get_default_ag(TALLOC_CTX *mem_ctx,
  69                                struct ldb_dn *dn,
  70                                struct security_token *token,
  71                                struct ldb_context *ldb)
  72 {
  73         TALLOC_CTX *tmp_ctx = talloc_new(mem_ctx);
  74         struct ldb_dn *root_base_dn = ldb_get_root_basedn(ldb);
  75         struct ldb_dn *schema_base_dn = ldb_get_schema_basedn(ldb);
  76         struct ldb_dn *config_base_dn = ldb_get_config_basedn(ldb);
  77         const struct dom_sid *domain_sid = samdb_domain_sid(ldb);
  78         struct dom_sid *da_sid = dom_sid_add_rid(tmp_ctx, domain_sid, DOMAIN_RID_ADMINS);
  79         struct dom_sid *ea_sid = dom_sid_add_rid(tmp_ctx, domain_sid, DOMAIN_RID_ENTERPRISE_ADMINS);
  80         struct dom_sid *sa_sid = dom_sid_add_rid(tmp_ctx, domain_sid, DOMAIN_RID_SCHEMA_ADMINS);
  81         struct dom_sid *dag_sid;
  82
  83         if (ldb_dn_compare_base(schema_base_dn, dn) == 0){
  84                 if (security_token_has_sid(token, sa_sid))
  85                         dag_sid = dom_sid_dup(mem_ctx, sa_sid);
  86                 else if (security_token_has_sid(token, ea_sid))
  87                         dag_sid = dom_sid_dup(mem_ctx, ea_sid);
  88                 else if (security_token_has_sid(token, da_sid))
  89                         dag_sid = dom_sid_dup(mem_ctx, da_sid);
  90                 else
  91                         dag_sid = NULL;
  92         }
  93         else if (ldb_dn_compare_base(config_base_dn, dn) == 0){
  94                 if (security_token_has_sid(token, ea_sid))
  95                         dag_sid = dom_sid_dup(mem_ctx, ea_sid);
  96                 else if (security_token_has_sid(token, da_sid))
  97                         dag_sid = dom_sid_dup(mem_ctx, da_sid);
  98                 else
  99                         dag_sid = NULL;
 100         }
 101         else if (ldb_dn_compare_base(root_base_dn, dn) == 0){
 102                 if (security_token_has_sid(token, da_sid))
 103                         dag_sid = dom_sid_dup(mem_ctx, da_sid);
 104                 else if (security_token_has_sid(token, ea_sid))
 105                                 dag_sid = dom_sid_dup(mem_ctx, ea_sid);
 106                 else
 107                         dag_sid = NULL;
 108         }
 109         else
 110                 dag_sid = NULL;
 111
 112         talloc_free(tmp_ctx);
 113         return dag_sid;
 114 }
 115
 116 static struct security_descriptor *get_sd_unpacked(struct ldb_module *module, TALLOC_CTX *mem_ctx,
 117                                             const struct dsdb_class *objectclass)
 118 {
 119         struct ldb_context *ldb = ldb_module_get_ctx(module);
 120         struct security_descriptor *sd;
 121         const struct dom_sid *domain_sid = samdb_domain_sid(ldb);
 122
 123         if (!objectclass->defaultSecurityDescriptor || !domain_sid) {
 124                 return NULL;
 125         }
 126
 127         sd = sddl_decode(mem_ctx,
 128                          objectclass->defaultSecurityDescriptor,
 129                          domain_sid);
 130         return sd;
 131 }
 132
 133 static struct dom_sid *get_default_group(TALLOC_CTX *mem_ctx,
 134                                          struct ldb_context *ldb,
 135                                          struct dom_sid *dag)
 136 {
 137         return dag;
 138 }
 139
 140 static DATA_BLOB *get_new_descriptor(struct ldb_module *module,
 141                                      struct ldb_dn *dn,
 142                                      TALLOC_CTX *mem_ctx,
 143                                      const struct dsdb_class *objectclass,
 144                                      struct ldb_val *parent,
 145                                      struct ldb_val *object)
 146 {
 147         struct security_descriptor *user_descriptor = NULL, *parent_descriptor = NULL;
 148         struct security_descriptor *new_sd;
 149         DATA_BLOB *linear_sd;
 150         enum ndr_err_code ndr_err;
 151         struct ldb_context *ldb = ldb_module_get_ctx(module);
 152         struct auth_session_info *session_info
 153                 = ldb_get_opaque(ldb, "sessionInfo");
 154         const struct dom_sid *domain_sid = samdb_domain_sid(ldb);
 155         char *sddl_sd;
 156         struct dom_sid *default_owner;
 157         struct dom_sid *default_group;
 158
 159         if (object){
 160                 user_descriptor = talloc(mem_ctx, struct security_descriptor);
 161                 if(!user_descriptor)
 162                         return NULL;
 163                 ndr_err = ndr_pull_struct_blob(object, user_descriptor, NULL,
 164                                                user_descriptor,
 165                                                (ndr_pull_flags_fn_t)ndr_pull_security_descriptor);
 166
 167                 if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)){
 168                         talloc_free(user_descriptor);
 169                         return NULL;
 170                 }
 171         }
 172         else
 173                 user_descriptor = get_sd_unpacked(module, mem_ctx, objectclass);
 174
 175         if (parent){
 176                 parent_descriptor = talloc(mem_ctx, struct security_descriptor);
 177                 if(!parent_descriptor)
 178                         return NULL;
 179                 ndr_err = ndr_pull_struct_blob(parent, parent_descriptor, NULL,
 180                                                parent_descriptor,
 181                                                (ndr_pull_flags_fn_t)ndr_pull_security_descriptor);
 182
 183                 if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)){
 184                         talloc_free(parent_descriptor);
 185                         return NULL;
 186                 }
 187         }
 188         default_owner = get_default_ag(mem_ctx, dn,
 189                                        session_info->security_token, ldb);
 190         default_group = get_default_group(mem_ctx, ldb, default_owner);
 191         new_sd = create_security_descriptor(mem_ctx, parent_descriptor, user_descriptor, true,
 192                                             NULL, SEC_DACL_AUTO_INHERIT|SEC_SACL_AUTO_INHERIT,
 193                                             session_info->security_token,
 194                                             default_owner, default_group,
 195                                             map_generic_rights_ds);
 196         if (!new_sd)
 197                 return NULL;
 198
 199
 200         sddl_sd = sddl_encode(mem_ctx, new_sd, domain_sid);
 201         DEBUG(10, ("Object %s created with desriptor %s", ldb_dn_get_linearized(dn), sddl_sd));
 202
 203         linear_sd = talloc(mem_ctx, DATA_BLOB);
 204         if (!linear_sd) {
 205                 return NULL;
 206         }
 207
 208         ndr_err = ndr_push_struct_blob(linear_sd, mem_ctx,
 209                                        lp_iconv_convenience(ldb_get_opaque(ldb, "loadparm")),
 210                                        new_sd,
 211                                        (ndr_push_flags_fn_t)ndr_push_security_descriptor);
 212         if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
 213                 return NULL;
 214         }
 215
 216         return linear_sd;
 217 }
 218
 219 static struct descriptor_context *descriptor_init_context(struct ldb_module *module,
 220                                                           struct ldb_request *req)
 221 {
 222         struct ldb_context *ldb;
 223         struct descriptor_context *ac;
 224
 225         ldb = ldb_module_get_ctx(module);
 226
 227         ac = talloc_zero(req, struct descriptor_context);
 228         if (ac == NULL) {
 229                 ldb_set_errstring(ldb, "Out of Memory");
 230                 return NULL;
 231         }
 232
 233         ac->module = module;
 234         ac->req = req;
 235         return ac;
 236 }
 237
 238 static int get_search_callback(struct ldb_request *req, struct ldb_reply *ares)
 239 {
 240         struct ldb_context *ldb;
 241         struct descriptor_context *ac;
 242         int ret;
 243
 244         ac = talloc_get_type(req->context, struct descriptor_context);
 245         ldb = ldb_module_get_ctx(ac->module);
 246
 247         if (!ares) {
 248                 return ldb_module_done(ac->req, NULL, NULL,
 249                                         LDB_ERR_OPERATIONS_ERROR);
 250         }
 251         if (ares->error != LDB_SUCCESS &&
 252             ares->error != LDB_ERR_NO_SUCH_OBJECT) {
 253                 return ldb_module_done(ac->req, ares->controls,
 254                                         ares->response, ares->error);
 255         }
 256
 257         switch (ares->type) {
 258         case LDB_REPLY_ENTRY:
 259                 if (ac->search_res != NULL) {
 260                         ldb_set_errstring(ldb, "Too many results");
 261                         talloc_free(ares);
 262                         return ldb_module_done(ac->req, NULL, NULL,
 263                                                 LDB_ERR_OPERATIONS_ERROR);
 264                 }
 265
 266                 ac->search_res = talloc_steal(ac, ares);
 267                 break;
 268
 269         case LDB_REPLY_REFERRAL:
 270                 /* ignore */
 271                 talloc_free(ares);
 272                 break;
 273
 274         case LDB_REPLY_DONE:
 275                 talloc_free(ares);
 276                 ret = ac->step_fn(ac);
 277                 if (ret != LDB_SUCCESS) {
 278                         return ldb_module_done(ac->req, NULL, NULL, ret);
 279                 }
 280                 break;
 281         }
 282
 283         return LDB_SUCCESS;
 284 }
 285 static int descriptor_op_callback(struct ldb_request *req, struct ldb_reply *ares)
 286 {
 287         struct descriptor_context *ac;
 288
 289         ac = talloc_get_type(req->context, struct descriptor_context);
 290
 291         if (!ares) {
 292                 return ldb_module_done(ac->req, NULL, NULL,
 293                                         LDB_ERR_OPERATIONS_ERROR);
 294         }
 295         if (ares->error != LDB_SUCCESS) {
 296                 return ldb_module_done(ac->req, ares->controls,
 297                                         ares->response, ares->error);
 298         }
 299
 300         if (ares->type != LDB_REPLY_DONE) {
 301                 talloc_free(ares);
 302                 return ldb_module_done(ac->req, NULL, NULL,
 303                                         LDB_ERR_OPERATIONS_ERROR);
 304         }
 305
 306         return ldb_module_done(ac->req, ares->controls,
 307                                 ares->response, ares->error);
 308 }
 309
 310 static int descriptor_do_add(struct descriptor_context *ac)
 311 {
 312         struct ldb_context *ldb;
 313         const struct dsdb_schema *schema;
 314         struct ldb_request *add_req;
 315         struct ldb_message_element *objectclass_element, *sd_element = NULL;
 316         struct ldb_message *msg;
 317         TALLOC_CTX *mem_ctx;
 318         int ret;
 319         struct ldb_val *sd_val = NULL, *parentsd_val = NULL;
 320         DATA_BLOB *sd;
 321         struct dsdb_class *objectclass;
 322
 323         ldb = ldb_module_get_ctx(ac->module);
 324         schema = dsdb_get_schema(ldb);
 325
 326         mem_ctx = talloc_new(ac);
 327         if (mem_ctx == NULL) {
 328                 return LDB_ERR_OPERATIONS_ERROR;
 329         }
 330
 331         msg = ldb_msg_copy_shallow(ac, ac->req->op.add.message);
 332
 333         /* get the security descriptor values*/
 334         sd_element = ldb_msg_find_element(msg, "nTSecurityDescriptor");
 335         objectclass_element = ldb_msg_find_element(msg, "objectClass");
 336         objectclass = get_last_structural_class(schema, objectclass_element);
 337
 338         if (!objectclass)
 339                 return LDB_ERR_OPERATIONS_ERROR;
 340
 341         if (sd_element)
 342                 sd_val = &sd_element->values[0];
 343         /* NC's have no parent */
 344         if ((ldb_dn_compare(msg->dn, (ldb_get_schema_basedn(ldb))) == 0) ||
 345                         (ldb_dn_compare(msg->dn, (ldb_get_config_basedn(ldb))) == 0) ||
 346                         (ldb_dn_compare(msg->dn, (ldb_get_root_basedn(ldb))) == 0))
 347                 parentsd_val = NULL;
 348         else if (ac->search_res != NULL)
 349                 parentsd_val = ldb_msg_find_ldb_val(ac->search_res->message, "nTSecurityDescriptor");
 350
 351
 352         /* get the parent descriptor and the one provided. If not provided, get the default.*/
 353         /* convert to security descriptor and calculate */
 354         sd = get_new_descriptor(ac->module, msg->dn, mem_ctx, objectclass,
 355                         parentsd_val, sd_val);
 356         if (sd) {
 357                 ldb_msg_add_steal_value(msg, "nTSecurityDescriptor", sd);
 358         }
 359
 360         talloc_free(mem_ctx);
 361         ret = ldb_msg_sanity_check(ldb, msg);
 362
 363         if (ret != LDB_SUCCESS) {
 364                 return ret;
 365         }
 366
 367         ret = ldb_build_add_req(&add_req, ldb, ac,
 368                                 msg,
 369                                 ac->req->controls,
 370                                 ac, descriptor_op_callback,
 371                                 ac->req);
 372         if (ret != LDB_SUCCESS) {
 373                 return ret;
 374         }
 375
 376         /* perform the add */
 377         return ldb_next_request(ac->module, add_req);
 378 }
 379
 380 static int descriptor_add(struct ldb_module *module, struct ldb_request *req)
 381 {
 382         struct ldb_context *ldb;
 383         struct ldb_request *search_req;
 384         struct descriptor_context *ac;
 385         struct ldb_dn *parent_dn;
 386         int ret;
 387         static const char * const descr_attrs[] = { "nTSecurityDescriptor", NULL };
 388
 389         ldb = ldb_module_get_ctx(module);
 390
 391         ldb_debug(ldb, LDB_DEBUG_TRACE, "descriptor_add\n");
 392
 393         if (ldb_dn_is_special(req->op.add.message->dn)) {
 394                 return ldb_next_request(module, req);
 395         }
 396
 397         ac = descriptor_init_context(module, req);
 398         if (ac == NULL) {
 399                 return LDB_ERR_OPERATIONS_ERROR;
 400         }
 401
 402         /* If there isn't a parent, just go on to the add processing */
 403         if (ldb_dn_get_comp_num(ac->req->op.add.message->dn) == 1) {
 404                 return descriptor_do_add(ac);
 405         }
 406
 407         /* get copy of parent DN */
 408         parent_dn = ldb_dn_get_parent(ac, ac->req->op.add.message->dn);
 409         if (parent_dn == NULL) {
 410                 ldb_oom(ldb);
 411                 return LDB_ERR_OPERATIONS_ERROR;
 412         }
 413
 414         ret = ldb_build_search_req(&search_req, ldb,
 415                                    ac, parent_dn, LDB_SCOPE_BASE,
 416                                    "(objectClass=*)", descr_attrs,
 417                                    NULL,
 418                                    ac, get_search_callback,
 419                                    req);
 420         if (ret != LDB_SUCCESS) {
 421                 return ret;
 422         }
 423         talloc_steal(search_req, parent_dn);
 424
 425         ac->step_fn = descriptor_do_add;
 426
 427         return ldb_next_request(ac->module, search_req);
 428 }
 429 /* TODO */
 430 static int descriptor_modify(struct ldb_module *module, struct ldb_request *req)
 431 {
 432         struct ldb_context *ldb = ldb_module_get_ctx(module);
 433         ldb_debug(ldb, LDB_DEBUG_TRACE, "descriptor_modify\n");
 434         return ldb_next_request(module, req);
 435 }
 436 /* TODO */
 437 static int descriptor_rename(struct ldb_module *module, struct ldb_request *req)
 438 {
 439         struct ldb_context *ldb = ldb_module_get_ctx(module);
 440         ldb_debug(ldb, LDB_DEBUG_TRACE, "descriptor_rename\n");
 441         return ldb_next_request(module, req);
 442 }
 443
 444 _PUBLIC_ const struct ldb_module_ops ldb_descriptor_module_ops = {
 445         .name              = "descriptor",
 446         .add           = descriptor_add,
 447         .modify        = descriptor_modify,
 448         .rename        = descriptor_rename,
 449 };
 450
 451