0b5994bb8896ed04e84b6e94e1bc2c2fe42af7e8
[ira/wip.git] / source4 / dsdb / samdb / ldb_modules / kludge_acl.c
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) 
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) 
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,
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,
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)
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)
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)
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)
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)
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 };