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DEFINITIONS
This source file includes following definitions.
- what_is_user
- user_name
- kludge_acl_allowedAttributes
- kludge_acl_childClasses
- kludge_acl_callback
- kludge_acl_search
- kludge_acl_change
- kludge_acl_extended
- kludge_acl_init
1 /*
2 ldb database library
3
4 Copyright (C) Andrew Bartlett 2005
5 Copyright (C) Simo Sorce 2006-2008
6
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.
11
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.
16
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/>.
19 */
20
21 /*
22 * Name: ldb
23 *
24 * Component: ldb kludge ACL module
25 *
26 * Description: Simple module to enforce a simple form of access
27 * control, sufficient for securing a default Samba4
28 * installation.
29 *
30 * Author: Andrew Bartlett
31 */
32
33 #include "includes.h"
34 #include "ldb_module.h"
35 #include "auth/auth.h"
36 #include "libcli/security/security.h"
37 #include "dsdb/samdb/samdb.h"
38
39 /* Kludge ACL rules:
40 *
41 * - System can read passwords
42 * - Administrators can write anything
43 * - Users can read anything that is not a password
44 *
45 */
46
47 struct kludge_private_data {
48 const char **password_attrs;
49 };
50
51 static enum security_user_level what_is_user(struct ldb_module *module)
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52 {
53 struct ldb_context *ldb = ldb_module_get_ctx(module);
54 struct auth_session_info *session_info
55 = (struct auth_session_info *)ldb_get_opaque(ldb, "sessionInfo");
56 return security_session_user_level(session_info);
57 }
58
59 static const char *user_name(TALLOC_CTX *mem_ctx, struct ldb_module *module)
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60 {
61 struct ldb_context *ldb = ldb_module_get_ctx(module);
62 struct auth_session_info *session_info
63 = (struct auth_session_info *)ldb_get_opaque(ldb, "sessionInfo");
64 if (!session_info) {
65 return "UNKNOWN (NULL)";
66 }
67
68 return talloc_asprintf(mem_ctx, "%s\\%s",
69 session_info->server_info->domain_name,
70 session_info->server_info->account_name);
71 }
72
73 /* search */
74 struct kludge_acl_context {
75
76 struct ldb_module *module;
77 struct ldb_request *req;
78
79 enum security_user_level user_type;
80 bool allowedAttributes;
81 bool allowedAttributesEffective;
82 bool allowedChildClasses;
83 bool allowedChildClassesEffective;
84 const char * const *attrs;
85 };
86
87 /* read all objectClasses */
88
89 static int kludge_acl_allowedAttributes(struct ldb_context *ldb, struct ldb_message *msg,
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90 const char *attrName)
91 {
92 struct ldb_message_element *oc_el;
93 struct ldb_message_element *allowedAttributes;
94 const struct dsdb_schema *schema = dsdb_get_schema(ldb);
95 TALLOC_CTX *mem_ctx;
96 const char **objectclass_list, **attr_list;
97 int i, ret;
98
99 /* If we don't have a schema yet, we can't do anything... */
100 if (schema == NULL) {
101 return LDB_SUCCESS;
102 }
103
104 /* Must remove any existing attribute, or else confusion reins */
105 ldb_msg_remove_attr(msg, attrName);
106 ret = ldb_msg_add_empty(msg, attrName, 0, &allowedAttributes);
107 if (ret != LDB_SUCCESS) {
108 return ret;
109 }
110
111 mem_ctx = talloc_new(msg);
112 if (!mem_ctx) {
113 ldb_oom(ldb);
114 return LDB_ERR_OPERATIONS_ERROR;
115 }
116
117 /* To ensure that oc_el is valid, we must look for it after
118 we alter the element array in ldb_msg_add_empty() */
119 oc_el = ldb_msg_find_element(msg, "objectClass");
120
121 objectclass_list = talloc_array(mem_ctx, const char *, oc_el->num_values + 1);
122 if (!objectclass_list) {
123 ldb_oom(ldb);
124 talloc_free(mem_ctx);
125 return LDB_ERR_OPERATIONS_ERROR;
126 }
127
128 for (i=0; oc_el && i < oc_el->num_values; i++) {
129 objectclass_list[i] = (const char *)oc_el->values[i].data;
130 }
131 objectclass_list[i] = NULL;
132
133 attr_list = dsdb_full_attribute_list(mem_ctx, schema, objectclass_list, DSDB_SCHEMA_ALL);
134 if (!attr_list) {
135 ldb_asprintf_errstring(ldb, "kludge_acl: Failed to get list of attributes create %s attribute", attrName);
136 talloc_free(mem_ctx);
137 return LDB_ERR_OPERATIONS_ERROR;
138 }
139
140 for (i=0; attr_list && attr_list[i]; i++) {
141 ldb_msg_add_string(msg, attrName, attr_list[i]);
142 }
143 talloc_free(mem_ctx);
144 return LDB_SUCCESS;
145
146 }
147 /* read all objectClasses */
148
149 static int kludge_acl_childClasses(struct ldb_context *ldb, struct ldb_message *msg,
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150 const char *attrName)
151 {
152 struct ldb_message_element *oc_el;
153 struct ldb_message_element *allowedClasses;
154 const struct dsdb_schema *schema = dsdb_get_schema(ldb);
155 const struct dsdb_class *sclass;
156 int i, j, ret;
157
158 /* If we don't have a schema yet, we can't do anything... */
159 if (schema == NULL) {
160 return LDB_SUCCESS;
161 }
162
163 /* Must remove any existing attribute, or else confusion reins */
164 ldb_msg_remove_attr(msg, attrName);
165 ret = ldb_msg_add_empty(msg, attrName, 0, &allowedClasses);
166 if (ret != LDB_SUCCESS) {
167 return ret;
168 }
169
170 /* To ensure that oc_el is valid, we must look for it after
171 we alter the element array in ldb_msg_add_empty() */
172 oc_el = ldb_msg_find_element(msg, "objectClass");
173
174 for (i=0; oc_el && i < oc_el->num_values; i++) {
175 sclass = dsdb_class_by_lDAPDisplayName(schema, (const char *)oc_el->values[i].data);
176 if (!sclass) {
177 /* We don't know this class? what is going on? */
178 continue;
179 }
180
181 for (j=0; sclass->possibleInferiors && sclass->possibleInferiors[j]; j++) {
182 ldb_msg_add_string(msg, attrName, sclass->possibleInferiors[j]);
183 }
184 }
185
186 if (allowedClasses->num_values > 1) {
187 qsort(allowedClasses->values,
188 allowedClasses->num_values,
189 sizeof(*allowedClasses->values),
190 (comparison_fn_t)data_blob_cmp);
191
192 for (i=1 ; i < allowedClasses->num_values; i++) {
193
194 struct ldb_val *val1 = &allowedClasses->values[i-1];
195 struct ldb_val *val2 = &allowedClasses->values[i];
196 if (data_blob_cmp(val1, val2) == 0) {
197 memmove(val1, val2, (allowedClasses->num_values - i) * sizeof( struct ldb_val));
198 allowedClasses->num_values--;
199 i--;
200 }
201 }
202 }
203
204 return LDB_SUCCESS;
205
206 }
207
208 /* find all attributes allowed by all these objectClasses */
209
210 static int kludge_acl_callback(struct ldb_request *req, struct ldb_reply *ares)
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211 {
212 struct ldb_context *ldb;
213 struct kludge_acl_context *ac;
214 struct kludge_private_data *data;
215 int i, ret;
216
217 ac = talloc_get_type(req->context, struct kludge_acl_context);
218 data = talloc_get_type(ldb_module_get_private(ac->module), struct kludge_private_data);
219 ldb = ldb_module_get_ctx(ac->module);
220
221 if (!ares) {
222 return ldb_module_done(ac->req, NULL, NULL,
223 LDB_ERR_OPERATIONS_ERROR);
224 }
225 if (ares->error != LDB_SUCCESS) {
226 return ldb_module_done(ac->req, ares->controls,
227 ares->response, ares->error);
228 }
229
230 switch (ares->type) {
231 case LDB_REPLY_ENTRY:
232 if (ac->allowedAttributes) {
233 ret = kludge_acl_allowedAttributes(ldb,
234 ares->message,
235 "allowedAttributes");
236 if (ret != LDB_SUCCESS) {
237 return ldb_module_done(ac->req, NULL, NULL, ret);
238 }
239 }
240 if (ac->allowedChildClasses) {
241 ret = kludge_acl_childClasses(ldb,
242 ares->message,
243 "allowedChildClasses");
244 if (ret != LDB_SUCCESS) {
245 return ldb_module_done(ac->req, NULL, NULL, ret);
246 }
247 }
248
249 if (data && data->password_attrs) /* if we are not initialized just get through */
250 {
251 switch (ac->user_type) {
252 case SECURITY_SYSTEM:
253 if (ac->allowedAttributesEffective) {
254 ret = kludge_acl_allowedAttributes(ldb, ares->message,
255 "allowedAttributesEffective");
256 if (ret != LDB_SUCCESS) {
257 return ldb_module_done(ac->req, NULL, NULL, ret);
258 }
259 }
260 if (ac->allowedChildClassesEffective) {
261 ret = kludge_acl_childClasses(ldb, ares->message,
262 "allowedChildClassesEffective");
263 if (ret != LDB_SUCCESS) {
264 return ldb_module_done(ac->req, NULL, NULL, ret);
265 }
266 }
267 break;
268
269 case SECURITY_ADMINISTRATOR:
270 if (ac->allowedAttributesEffective) {
271 ret = kludge_acl_allowedAttributes(ldb, ares->message,
272 "allowedAttributesEffective");
273 if (ret != LDB_SUCCESS) {
274 return ldb_module_done(ac->req, NULL, NULL, ret);
275 }
276 }
277 if (ac->allowedChildClassesEffective) {
278 ret = kludge_acl_childClasses(ldb, ares->message,
279 "allowedChildClassesEffective");
280 if (ret != LDB_SUCCESS) {
281 return ldb_module_done(ac->req, NULL, NULL, ret);
282 }
283 }
284 /* fall through */
285 default:
286 /* remove password attributes */
287 for (i = 0; data->password_attrs[i]; i++) {
288 ldb_msg_remove_attr(ares->message, data->password_attrs[i]);
289 }
290 }
291 }
292
293 if (ac->allowedAttributes ||
294 ac->allowedAttributesEffective ||
295 ac->allowedChildClasses ||
296 ac->allowedChildClassesEffective) {
297
298 if (!ldb_attr_in_list(ac->attrs, "objectClass") &&
299 !ldb_attr_in_list(ac->attrs, "*")) {
300
301 ldb_msg_remove_attr(ares->message,
302 "objectClass");
303 }
304 }
305
306 return ldb_module_send_entry(ac->req, ares->message, ares->controls);
307
308 case LDB_REPLY_REFERRAL:
309 return ldb_module_send_referral(ac->req, ares->referral);
310
311 case LDB_REPLY_DONE:
312 return ldb_module_done(ac->req, ares->controls,
313 ares->response, LDB_SUCCESS);
314
315 }
316 return LDB_SUCCESS;
317 }
318
319 static int kludge_acl_search(struct ldb_module *module, struct ldb_request *req)
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320 {
321 struct ldb_context *ldb;
322 struct kludge_acl_context *ac;
323 struct ldb_request *down_req;
324 struct kludge_private_data *data;
325 const char * const *attrs;
326 int ret, i;
327 struct ldb_control *sd_control;
328 struct ldb_control **sd_saved_controls;
329
330 ldb = ldb_module_get_ctx(module);
331
332 ac = talloc(req, struct kludge_acl_context);
333 if (ac == NULL) {
334 ldb_oom(ldb);
335 return LDB_ERR_OPERATIONS_ERROR;
336 }
337
338 data = talloc_get_type(ldb_module_get_private(module), struct kludge_private_data);
339
340 ac->module = module;
341 ac->req = req;
342 ac->user_type = what_is_user(module);
343 ac->attrs = req->op.search.attrs;
344
345 ac->allowedAttributes = ldb_attr_in_list(req->op.search.attrs, "allowedAttributes");
346
347 ac->allowedAttributesEffective = ldb_attr_in_list(req->op.search.attrs, "allowedAttributesEffective");
348
349 ac->allowedChildClasses = ldb_attr_in_list(req->op.search.attrs, "allowedChildClasses");
350
351 ac->allowedChildClassesEffective = ldb_attr_in_list(req->op.search.attrs, "allowedChildClassesEffective");
352
353 if (ac->allowedAttributes || ac->allowedAttributesEffective || ac->allowedChildClasses || ac->allowedChildClassesEffective) {
354 attrs = ldb_attr_list_copy_add(ac, req->op.search.attrs, "objectClass");
355 } else {
356 attrs = req->op.search.attrs;
357 }
358
359 /* replace any attributes in the parse tree that are private,
360 so we don't allow a search for 'userPassword=penguin',
361 just as we would not allow that attribute to be returned */
362 switch (ac->user_type) {
363 case SECURITY_SYSTEM:
364 break;
365 default:
366 /* FIXME: We should copy the tree and keep the original unmodified. */
367 /* remove password attributes */
368
369 if (!data || !data->password_attrs) {
370 break;
371 }
372 for (i = 0; data->password_attrs[i]; i++) {
373 ldb_parse_tree_attr_replace(req->op.search.tree,
374 data->password_attrs[i],
375 "kludgeACLredactedattribute");
376 }
377 }
378
379 ret = ldb_build_search_req_ex(&down_req,
380 ldb, ac,
381 req->op.search.base,
382 req->op.search.scope,
383 req->op.search.tree,
384 attrs,
385 req->controls,
386 ac, kludge_acl_callback,
387 req);
388 if (ret != LDB_SUCCESS) {
389 return LDB_ERR_OPERATIONS_ERROR;
390 }
391
392 /* check if there's an SD_FLAGS control */
393 sd_control = ldb_request_get_control(down_req, LDB_CONTROL_SD_FLAGS_OID);
394 if (sd_control) {
395 /* save it locally and remove it from the list */
396 /* we do not need to replace them later as we
397 * are keeping the original req intact */
398 if (!save_controls(sd_control, down_req, &sd_saved_controls)) {
399 return LDB_ERR_OPERATIONS_ERROR;
400 }
401 }
402
403 /* perform the search */
404 return ldb_next_request(module, down_req);
405 }
406
407 /* ANY change type */
408 static int kludge_acl_change(struct ldb_module *module, struct ldb_request *req)
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409 {
410 struct ldb_context *ldb = ldb_module_get_ctx(module);
411 enum security_user_level user_type = what_is_user(module);
412 switch (user_type) {
413 case SECURITY_SYSTEM:
414 case SECURITY_ADMINISTRATOR:
415 return ldb_next_request(module, req);
416 default:
417 ldb_asprintf_errstring(ldb,
418 "kludge_acl_change: "
419 "attempted database modify not permitted. "
420 "User %s is not SYSTEM or an administrator",
421 user_name(req, module));
422 return LDB_ERR_INSUFFICIENT_ACCESS_RIGHTS;
423 }
424 }
425
426 static int kludge_acl_extended(struct ldb_module *module, struct ldb_request *req)
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427 {
428 struct ldb_context *ldb = ldb_module_get_ctx(module);
429 enum security_user_level user_type;
430
431 /* allow everybody to read the sequence number */
432 if (strcmp(req->op.extended.oid,
433 LDB_EXTENDED_SEQUENCE_NUMBER) == 0) {
434 return ldb_next_request(module, req);
435 }
436
437 user_type = what_is_user(module);
438
439 switch (user_type) {
440 case SECURITY_SYSTEM:
441 case SECURITY_ADMINISTRATOR:
442 return ldb_next_request(module, req);
443 default:
444 ldb_asprintf_errstring(ldb,
445 "kludge_acl_change: "
446 "attempted database modify not permitted. "
447 "User %s is not SYSTEM or an administrator",
448 user_name(req, module));
449 return LDB_ERR_INSUFFICIENT_ACCESS_RIGHTS;
450 }
451 }
452
453 static int kludge_acl_init(struct ldb_module *module)
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454 {
455 struct ldb_context *ldb;
456 int ret, i;
457 TALLOC_CTX *mem_ctx = talloc_new(module);
458 static const char *attrs[] = { "passwordAttribute", NULL };
459 struct ldb_result *res;
460 struct ldb_message *msg;
461 struct ldb_message_element *password_attributes;
462
463 struct kludge_private_data *data;
464
465 ldb = ldb_module_get_ctx(module);
466
467 data = talloc(module, struct kludge_private_data);
468 if (data == NULL) {
469 ldb_oom(ldb);
470 return LDB_ERR_OPERATIONS_ERROR;
471 }
472
473 data->password_attrs = NULL;
474 ldb_module_set_private(module, data);
475
476 if (!mem_ctx) {
477 ldb_oom(ldb);
478 return LDB_ERR_OPERATIONS_ERROR;
479 }
480
481 ret = ldb_search(ldb, mem_ctx, &res,
482 ldb_dn_new(mem_ctx, ldb, "@KLUDGEACL"),
483 LDB_SCOPE_BASE, attrs, NULL);
484 if (ret != LDB_SUCCESS) {
485 goto done;
486 }
487 if (res->count == 0) {
488 goto done;
489 }
490
491 if (res->count > 1) {
492 talloc_free(mem_ctx);
493 return LDB_ERR_CONSTRAINT_VIOLATION;
494 }
495
496 msg = res->msgs[0];
497
498 password_attributes = ldb_msg_find_element(msg, "passwordAttribute");
499 if (!password_attributes) {
500 goto done;
501 }
502 data->password_attrs = talloc_array(data, const char *, password_attributes->num_values + 1);
503 if (!data->password_attrs) {
504 talloc_free(mem_ctx);
505 ldb_oom(ldb);
506 return LDB_ERR_OPERATIONS_ERROR;
507 }
508 for (i=0; i < password_attributes->num_values; i++) {
509 data->password_attrs[i] = (const char *)password_attributes->values[i].data;
510 talloc_steal(data->password_attrs, password_attributes->values[i].data);
511 }
512 data->password_attrs[i] = NULL;
513
514 ret = ldb_mod_register_control(module, LDB_CONTROL_SD_FLAGS_OID);
515 if (ret != LDB_SUCCESS) {
516 ldb_debug(ldb, LDB_DEBUG_ERROR,
517 "partition: Unable to register control with rootdse!\n");
518 return LDB_ERR_OPERATIONS_ERROR;
519 }
520
521 done:
522 talloc_free(mem_ctx);
523 return ldb_next_init(module);
524 }
525
526 _PUBLIC_ const struct ldb_module_ops ldb_kludge_acl_module_ops = {
527 .name = "kludge_acl",
528 .search = kludge_acl_search,
529 .add = kludge_acl_change,
530 .modify = kludge_acl_change,
531 .del = kludge_acl_change,
532 .rename = kludge_acl_change,
533 .extended = kludge_acl_extended,
534 .init_context = kludge_acl_init
535 };