4 Copyright (C) Simo Sorce 2006-2008
5 Copyright (C) Nadezhda Ivanova 2010
7 This program is free software; you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 3 of the License, or
10 (at your option) any later version.
12 This program is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
17 You should have received a copy of the GNU General Public License
18 along with this program. If not, see <http://www.gnu.org/licenses/>.
24 * Component: ldb ACL Read module
26 * Description: Module that performs authorisation access checks on read requests
27 * Only DACL checks implemented at this point
29 * Author: Nadezhda Ivanova
33 #include "ldb_module.h"
34 #include "auth/auth.h"
35 #include "libcli/security/security.h"
36 #include "dsdb/samdb/samdb.h"
37 #include "librpc/gen_ndr/ndr_security.h"
38 #include "param/param.h"
39 #include "dsdb/samdb/ldb_modules/util.h"
42 struct aclread_context {
43 struct ldb_module *module;
44 struct ldb_request *req;
45 const char * const *attrs;
46 const struct dsdb_schema *schema;
54 struct aclread_private {
58 static void aclread_mark_inaccesslible(struct ldb_message_element *el) {
59 el->flags |= LDB_FLAG_INTERNAL_INACCESSIBLE_ATTRIBUTE;
62 static bool aclread_is_inaccessible(struct ldb_message_element *el) {
63 return el->flags & LDB_FLAG_INTERNAL_INACCESSIBLE_ATTRIBUTE;
66 static int aclread_callback(struct ldb_request *req, struct ldb_reply *ares)
68 struct ldb_context *ldb;
69 struct aclread_context *ac;
70 struct ldb_message *ret_msg;
71 struct ldb_message *msg;
72 int ret, num_of_attrs = 0;
73 unsigned int i, k = 0;
74 struct security_descriptor *sd;
75 struct dom_sid *sid = NULL;
77 uint32_t instanceType;
79 ac = talloc_get_type(req->context, struct aclread_context);
80 ldb = ldb_module_get_ctx(ac->module);
82 return ldb_module_done(ac->req, NULL, NULL, LDB_ERR_OPERATIONS_ERROR );
84 if (ares->error != LDB_SUCCESS) {
85 return ldb_module_done(ac->req, ares->controls,
86 ares->response, ares->error);
88 tmp_ctx = talloc_new(ac);
92 ret = dsdb_get_sd_from_ldb_message(ldb, tmp_ctx, msg, &sd);
93 if (ret != LDB_SUCCESS || sd == NULL ) {
94 DEBUG(10, ("acl_read: cannot get descriptor\n"));
95 ret = LDB_ERR_OPERATIONS_ERROR;
98 sid = samdb_result_dom_sid(tmp_ctx, msg, "objectSid");
99 /* get the object instance type */
100 instanceType = ldb_msg_find_attr_as_uint(msg,
102 if (!ldb_dn_is_null(msg->dn) && !(instanceType & INSTANCE_TYPE_IS_NC_HEAD))
104 /* the object has a parent, so we have to check for visibility */
105 struct ldb_dn *parent_dn = ldb_dn_get_parent(tmp_ctx, msg->dn);
107 ret = dsdb_module_check_access_on_dn(ac->module,
112 if (ret == LDB_ERR_INSUFFICIENT_ACCESS_RIGHTS) {
113 talloc_free(tmp_ctx);
115 } else if (ret != LDB_SUCCESS) {
119 /* for every element in the message check RP */
120 for (i=0; i < msg->num_elements; i++) {
121 const struct dsdb_attribute *attr;
122 bool is_sd, is_objectsid, is_instancetype;
123 uint32_t access_mask;
124 attr = dsdb_attribute_by_lDAPDisplayName(ac->schema,
125 msg->elements[i].name);
127 DEBUG(2, ("acl_read: cannot find attribute %s in schema\n",
128 msg->elements[i].name));
129 ret = LDB_ERR_OPERATIONS_ERROR;
132 is_sd = ldb_attr_cmp("nTSecurityDescriptor",
133 msg->elements[i].name) == 0;
134 is_objectsid = ldb_attr_cmp("objectSid",
135 msg->elements[i].name) == 0;
136 is_instancetype = ldb_attr_cmp("instanceType",
137 msg->elements[i].name) == 0;
138 /* these attributes were added to perform access checks and must be removed */
139 if (is_objectsid && ac->object_sid) {
140 aclread_mark_inaccesslible(&msg->elements[i]);
143 if (is_instancetype && ac->instance_type) {
144 aclread_mark_inaccesslible(&msg->elements[i]);
147 if (is_sd && ac->sd) {
148 aclread_mark_inaccesslible(&msg->elements[i]);
151 /* nTSecurityDescriptor is a special case */
155 if (ac->sd_flags & (SECINFO_OWNER|SECINFO_GROUP)) {
156 access_mask |= SEC_STD_READ_CONTROL;
158 if (ac->sd_flags & SECINFO_DACL) {
159 access_mask |= SEC_STD_READ_CONTROL;
161 if (ac->sd_flags & SECINFO_SACL) {
162 access_mask |= SEC_FLAG_SYSTEM_SECURITY;
165 access_mask = SEC_ADS_READ_PROP;
168 if (attr->searchFlags & SEARCH_FLAG_CONFIDENTIAL) {
169 access_mask |= SEC_ADS_CONTROL_ACCESS;
172 if (access_mask == 0) {
173 aclread_mark_inaccesslible(&msg->elements[i]);
177 ret = acl_check_access_on_attribute(ac->module,
185 * Dirsync control needs the replpropertymetadata attribute
186 * so return it as it will be removed by the control
189 if (ret == LDB_ERR_INSUFFICIENT_ACCESS_RIGHTS) {
190 if (!ac->indirsync) {
192 * do not return this entry if attribute is
193 * part of the search filter
195 if (dsdb_attr_in_parse_tree(ac->req->op.search.tree,
196 msg->elements[i].name)) {
197 talloc_free(tmp_ctx);
200 aclread_mark_inaccesslible(&msg->elements[i]);
203 * We are doing dirysnc answers
204 * and the object shouldn't be returned (normally)
205 * but we will return it without replPropertyMetaData
206 * so that the dirysync module will do what is needed
207 * (remove the object if it is not deleted, or return
208 * just the objectGUID if it's deleted).
210 if (dsdb_attr_in_parse_tree(ac->req->op.search.tree,
211 msg->elements[i].name)) {
212 ldb_msg_remove_attr(msg, "replPropertyMetaData");
215 aclread_mark_inaccesslible(&msg->elements[i]);
218 } else if (ret != LDB_SUCCESS) {
222 for (i=0; i < msg->num_elements; i++) {
223 if (!aclread_is_inaccessible(&msg->elements[i])) {
227 /*create a new message to return*/
228 ret_msg = ldb_msg_new(ac->req);
229 ret_msg->dn = msg->dn;
230 talloc_steal(ret_msg, msg->dn);
231 ret_msg->num_elements = num_of_attrs;
232 if (num_of_attrs > 0) {
233 ret_msg->elements = talloc_array(ret_msg,
234 struct ldb_message_element,
236 if (ret_msg->elements == NULL) {
239 for (i=0; i < msg->num_elements; i++) {
240 bool to_remove = aclread_is_inaccessible(&msg->elements[i]);
242 ret_msg->elements[k] = msg->elements[i];
243 talloc_steal(ret_msg->elements, msg->elements[i].name);
244 talloc_steal(ret_msg->elements, msg->elements[i].values);
249 ret_msg->elements = NULL;
251 talloc_free(tmp_ctx);
253 return ldb_module_send_entry(ac->req, ret_msg, ares->controls);
254 case LDB_REPLY_REFERRAL:
255 return ldb_module_send_referral(ac->req, ares->referral);
257 return ldb_module_done(ac->req, ares->controls,
258 ares->response, LDB_SUCCESS);
263 talloc_free(tmp_ctx);
264 return ldb_module_done(ac->req, NULL, NULL, ret);
268 static int aclread_search(struct ldb_module *module, struct ldb_request *req)
270 struct ldb_context *ldb;
272 struct aclread_context *ac;
273 struct ldb_request *down_req;
274 struct ldb_control *as_system = ldb_request_get_control(req, LDB_CONTROL_AS_SYSTEM_OID);
275 uint32_t flags = ldb_req_get_custom_flags(req);
276 struct ldb_result *res;
277 struct aclread_private *p;
278 bool is_untrusted = ldb_req_is_untrusted(req);
279 const char * const *attrs = NULL;
280 uint32_t instanceType;
281 static const char *acl_attrs[] = {
286 ldb = ldb_module_get_ctx(module);
287 p = talloc_get_type(ldb_module_get_private(module), struct aclread_private);
289 /* skip access checks if we are system or system control is supplied
290 * or this is not LDAP server request */
291 if (!p || !p->enabled ||
292 dsdb_module_am_system(module)
293 || as_system || !is_untrusted) {
294 return ldb_next_request(module, req);
296 /* no checks on special dn */
297 if (ldb_dn_is_special(req->op.search.base)) {
298 return ldb_next_request(module, req);
301 /* check accessibility of base */
302 if (!ldb_dn_is_null(req->op.search.base)) {
303 ret = dsdb_module_search_dn(module, req, &res, req->op.search.base,
305 DSDB_FLAG_NEXT_MODULE |
306 DSDB_FLAG_AS_SYSTEM |
307 DSDB_SEARCH_SHOW_RECYCLED,
309 if (ret != LDB_SUCCESS) {
310 return ldb_error(ldb, ret,
311 "acl_read: Error retrieving instanceType for base.");
313 instanceType = ldb_msg_find_attr_as_uint(res->msgs[0],
315 if (instanceType != 0 && !(instanceType & INSTANCE_TYPE_IS_NC_HEAD))
317 /* the object has a parent, so we have to check for visibility */
318 struct ldb_dn *parent_dn = ldb_dn_get_parent(req, req->op.search.base);
319 ret = dsdb_module_check_access_on_dn(module,
324 if (ret == LDB_ERR_INSUFFICIENT_ACCESS_RIGHTS) {
325 return ldb_module_done(req, NULL, NULL, LDB_ERR_NO_SUCH_OBJECT);
326 } else if (ret != LDB_SUCCESS) {
327 return ldb_module_done(req, NULL, NULL, ret);
331 ac = talloc_zero(req, struct aclread_context);
337 ac->schema = dsdb_get_schema(ldb, req);
338 if (flags & DSDB_ACL_CHECKS_DIRSYNC_FLAG) {
339 ac->indirsync = true;
341 ac->indirsync = false;
344 return ldb_operr(ldb);
347 * In theory we should also check for the SD control but control verification is
348 * expensive so we'd better had the ntsecuritydescriptor to the list of
349 * searched attribute and then remove it !
351 ac->sd_flags = dsdb_request_sd_flags(ac->req, NULL);
353 ac->sd = !(ldb_attr_in_list(req->op.search.attrs, "nTSecurityDescriptor"));
354 if (req->op.search.attrs && !ldb_attr_in_list(req->op.search.attrs, "*")) {
355 if (!ldb_attr_in_list(req->op.search.attrs, "instanceType")) {
356 ac->instance_type = true;
357 attrs = ldb_attr_list_copy_add(ac, req->op.search.attrs, "instanceType");
359 attrs = req->op.search.attrs;
361 if (!ldb_attr_in_list(req->op.search.attrs, "objectSid")) {
362 ac->object_sid = true;
363 attrs = ldb_attr_list_copy_add(ac, attrs, "objectSid");
368 /* avoid replacing all attributes with nTSecurityDescriptor
369 * if attribute list is empty */
371 attrs = ldb_attr_list_copy_add(ac, req->op.search.attrs, "*");
373 attrs = ldb_attr_list_copy_add(ac, attrs, "nTSecurityDescriptor");
375 ac->attrs = req->op.search.attrs;
376 ret = ldb_build_search_req_ex(&down_req,
379 req->op.search.scope,
383 ac, aclread_callback,
386 if (ret != LDB_SUCCESS) {
387 return LDB_ERR_OPERATIONS_ERROR;
390 return ldb_next_request(module, down_req);
393 static int aclread_init(struct ldb_module *module)
395 struct ldb_context *ldb = ldb_module_get_ctx(module);
396 struct aclread_private *p = talloc_zero(module, struct aclread_private);
398 return ldb_module_oom(module);
400 p->enabled = lpcfg_parm_bool(ldb_get_opaque(ldb, "loadparm"), NULL, "acl", "search", true);
401 ldb_module_set_private(module, p);
402 return ldb_next_init(module);
405 static const struct ldb_module_ops ldb_aclread_module_ops = {
407 .search = aclread_search,
408 .init_context = aclread_init
411 int ldb_aclread_module_init(const char *version)
413 LDB_MODULE_CHECK_VERSION(version);
414 return ldb_register_module(&ldb_aclread_module_ops);