97130495a3adde2df3d54a8427cc366c0080a530
[ira/wip.git] / source / 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
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/include/ldb.h"
35 #include "ldb/include/ldb_errors.h"
36 #include "ldb/include/ldb_private.h"
37 #include "auth/auth.h"
38 #include "libcli/security/security.h"
39 #include "dsdb/samdb/samdb.h"
40
41 /* Kludge ACL rules:
42  *
43  * - System can read passwords
44  * - Administrators can write anything
45  * - Users can read anything that is not a password
46  *
47  */
48
49 enum user_is {
50         ANONYMOUS,
51         USER,
52         ADMINISTRATOR,
53         SYSTEM
54 };
55
56 struct kludge_private_data {
57         const char **password_attrs;
58 };
59
60 static enum user_is what_is_user(struct ldb_module *module) 
61 {
62         struct auth_session_info *session_info
63                 = (struct auth_session_info *)ldb_get_opaque(module->ldb, "sessionInfo");
64         if (!session_info) {
65                 return ANONYMOUS;
66         }
67         
68         if (security_token_is_system(session_info->security_token)) {
69                 return SYSTEM;
70         }
71
72         if (security_token_is_anonymous(session_info->security_token)) {
73                 return ANONYMOUS;
74         }
75
76         if (security_token_has_builtin_administrators(session_info->security_token)) {
77                 return ADMINISTRATOR;
78         }
79
80         if (security_token_has_nt_authenticated_users(session_info->security_token)) {
81                 return USER;
82         }
83
84         return ANONYMOUS;
85 }
86
87 static const char *user_name(TALLOC_CTX *mem_ctx, struct ldb_module *module) 
88 {
89         struct auth_session_info *session_info
90                 = (struct auth_session_info *)ldb_get_opaque(module->ldb, "sessionInfo");
91         if (!session_info) {
92                 return "UNKNOWN (NULL)";
93         }
94         
95         return talloc_asprintf(mem_ctx, "%s\\%s",
96                                session_info->server_info->domain_name,
97                                session_info->server_info->account_name);
98 }
99
100 /* search */
101 struct kludge_acl_context {
102
103         struct ldb_module *module;
104         void *up_context;
105         int (*up_callback)(struct ldb_context *, void *, struct ldb_reply *);
106
107         enum user_is user_type;
108         bool allowedAttributes;
109         bool allowedAttributesEffective;
110         bool allowedChildClasses;
111         bool allowedChildClassesEffective;
112         const char **attrs;
113 };
114
115 /* read all objectClasses */
116
117 static int kludge_acl_allowedAttributes(struct ldb_context *ldb, struct ldb_message *msg,
118                                         const char *attrName) 
119 {
120         struct ldb_message_element *oc_el;
121         struct ldb_message_element *allowedAttributes;
122         const struct dsdb_schema *schema = dsdb_get_schema(ldb);
123         const struct dsdb_class *class;
124         int i, j, ret;
125
126         /* If we don't have a schema yet, we can't do anything... */
127         if (schema == NULL) {
128                 return LDB_SUCCESS;
129         }
130
131         /* Must remove any existing attribute, or else confusion reins */
132         ldb_msg_remove_attr(msg, attrName);
133         ret = ldb_msg_add_empty(msg, attrName, 0, &allowedAttributes);
134         if (ret != LDB_SUCCESS) {
135                 return ret;
136         }
137         
138         /* To ensure that oc_el is valid, we must look for it after 
139            we alter the element array in ldb_msg_add_empty() */
140         oc_el = ldb_msg_find_element(msg, "objectClass");
141
142         for (i=0; oc_el && i < oc_el->num_values; i++) {
143                 class = dsdb_class_by_lDAPDisplayName(schema, (const char *)oc_el->values[i].data);
144                 if (!class) {
145                         /* We don't know this class?  what is going on? */
146                         continue;
147                 }
148
149                 for (j=0; class->mayContain && class->mayContain[j]; j++) {
150                         ldb_msg_add_string(msg, attrName, class->mayContain[j]);
151                 }
152                 for (j=0; class->mustContain && class->mustContain[j]; j++) {
153                         ldb_msg_add_string(msg, attrName, class->mustContain[j]);
154                 }
155                 for (j=0; class->systemMayContain && class->systemMayContain[j]; j++) {
156                         ldb_msg_add_string(msg, attrName, class->systemMayContain[j]);
157                 }
158                 for (j=0; class->systemMustContain && class->systemMustContain[j]; j++) {
159                         ldb_msg_add_string(msg, attrName, class->systemMustContain[j]);
160                 }
161         }
162                 
163         if (allowedAttributes->num_values > 1) {
164                 qsort(allowedAttributes->values, 
165                       allowedAttributes->num_values, 
166                       sizeof(*allowedAttributes->values),
167                       (comparison_fn_t)data_blob_cmp);
168         
169                 for (i=1 ; i < allowedAttributes->num_values; i++) {
170                         struct ldb_val *val1 = &allowedAttributes->values[i-1];
171                         struct ldb_val *val2 = &allowedAttributes->values[i];
172                         if (data_blob_cmp(val1, val2) == 0) {
173                                 memmove(val1, val2, (allowedAttributes->num_values - i) * sizeof( struct ldb_val)); 
174                                 allowedAttributes->num_values--;
175                                 i--;
176                         }
177                 }
178         }
179
180         return 0;
181
182 }
183 /* read all objectClasses */
184
185 static int kludge_acl_childClasses(struct ldb_context *ldb, struct ldb_message *msg,
186                                    const char *attrName) 
187 {
188         struct ldb_message_element *oc_el;
189         struct ldb_message_element *allowedClasses;
190         const struct dsdb_schema *schema = dsdb_get_schema(ldb);
191         const struct dsdb_class *class;
192         int i, j, ret;
193
194         /* If we don't have a schema yet, we can't do anything... */
195         if (schema == NULL) {
196                 return LDB_SUCCESS;
197         }
198
199         /* Must remove any existing attribute, or else confusion reins */
200         ldb_msg_remove_attr(msg, attrName);
201         ret = ldb_msg_add_empty(msg, attrName, 0, &allowedClasses);
202         if (ret != LDB_SUCCESS) {
203                 return ret;
204         }
205         
206         /* To ensure that oc_el is valid, we must look for it after 
207            we alter the element array in ldb_msg_add_empty() */
208         oc_el = ldb_msg_find_element(msg, "objectClass");
209
210         for (i=0; oc_el && i < oc_el->num_values; i++) {
211                 class = dsdb_class_by_lDAPDisplayName(schema, (const char *)oc_el->values[i].data);
212                 if (!class) {
213                         /* We don't know this class?  what is going on? */
214                         continue;
215                 }
216
217                 for (j=0; class->possibleInferiors && class->possibleInferiors[j]; j++) {
218                         ldb_msg_add_string(msg, attrName, class->possibleInferiors[j]);
219                 }
220         }
221                 
222         if (allowedClasses->num_values > 1) {
223                 qsort(allowedClasses->values, 
224                       allowedClasses->num_values, 
225                       sizeof(*allowedClasses->values),
226                       (comparison_fn_t)data_blob_cmp);
227         
228                 for (i=1 ; i < allowedClasses->num_values; i++) {
229                         struct ldb_val *val1 = &allowedClasses->values[i-1];
230                         struct ldb_val *val2 = &allowedClasses->values[i];
231                         if (data_blob_cmp(val1, val2) == 0) {
232                                 memmove(val1, val2, (allowedClasses->num_values - i) * sizeof( struct ldb_val)); 
233                                 allowedClasses->num_values--;
234                                 i--;
235                         }
236                 }
237         }
238
239         return 0;
240
241 }
242
243 /* find all attributes allowed by all these objectClasses */
244
245 static int kludge_acl_callback(struct ldb_context *ldb, void *context, struct ldb_reply *ares)
246 {
247         struct kludge_acl_context *ac;
248         struct kludge_private_data *data;
249         int i, ret;
250
251         ac = talloc_get_type(context, struct kludge_acl_context);
252         data = talloc_get_type(ac->module->private_data, struct kludge_private_data);
253
254         if (ares->type != LDB_REPLY_ENTRY) {
255                 return ac->up_callback(ldb, ac->up_context, ares);
256         }
257
258         if (ac->allowedAttributes) {
259                 ret = kludge_acl_allowedAttributes(ldb, ares->message, "allowedAttributes");
260                 if (ret != LDB_SUCCESS) {
261                         return ret;
262
263                 }
264         }
265         if (ac->allowedChildClasses) {
266                 ret = kludge_acl_childClasses(ldb, ares->message, "allowedChildClasses");
267                 if (ret != LDB_SUCCESS) {
268                         return ret;
269                 }
270         }
271
272         if (data && data->password_attrs) /* if we are not initialized just get through */
273         {
274                 switch (ac->user_type) {
275                 case SYSTEM:
276                 case ADMINISTRATOR:
277                         if (ac->allowedAttributesEffective) {
278                                 ret = kludge_acl_allowedAttributes(ldb, ares->message, "allowedAttributesEffective");
279                                 if (ret != LDB_SUCCESS) {
280                                         return ret;
281                                 }
282                         }
283                         if (ac->allowedChildClassesEffective) {
284                                 ret = kludge_acl_childClasses(ldb, ares->message, "allowedChildClassesEffective");
285                                 if (ret != LDB_SUCCESS) {
286                                         return ret;
287                                 }
288                         }
289                         break;
290                 default:
291                         /* remove password attributes */
292                         for (i = 0; data->password_attrs[i]; i++) {
293                                 ldb_msg_remove_attr(ares->message, data->password_attrs[i]);
294                         }
295                 }
296         }
297
298         if ((ac->allowedAttributes || ac->allowedAttributesEffective
299              || ac->allowedChildClasses || ac->allowedChildClassesEffective) && 
300             (!ldb_attr_in_list(ac->attrs, "objectClass") && 
301              !ldb_attr_in_list(ac->attrs, "*"))) {
302                 ldb_msg_remove_attr(ares->message, "objectClass");
303         }
304
305         return ac->up_callback(ldb, ac->up_context, ares);
306 }
307
308 static int kludge_acl_search(struct ldb_module *module, struct ldb_request *req)
309 {
310         struct kludge_acl_context *ac;
311         struct ldb_request *down_req;
312         struct kludge_private_data *data;
313         int ret, i;
314
315         req->handle = NULL;
316
317         ac = talloc(req, struct kludge_acl_context);
318         if (ac == NULL) {
319                 return LDB_ERR_OPERATIONS_ERROR;
320         }
321
322         data = talloc_get_type(module->private_data, struct kludge_private_data);
323
324         ac->module = module;
325         ac->up_context = req->context;
326         ac->up_callback = req->callback;
327         ac->user_type = what_is_user(module);
328         ac->attrs = req->op.search.attrs;
329
330         down_req = talloc_zero(req, struct ldb_request);
331         if (down_req == NULL) {
332                 return LDB_ERR_OPERATIONS_ERROR;
333         }
334
335         down_req->operation = req->operation;
336         down_req->op.search.base = req->op.search.base;
337         down_req->op.search.scope = req->op.search.scope;
338         down_req->op.search.tree = req->op.search.tree;
339         down_req->op.search.attrs = req->op.search.attrs;
340
341         ac->allowedAttributes = ldb_attr_in_list(req->op.search.attrs, "allowedAttributes");
342
343         ac->allowedAttributesEffective = ldb_attr_in_list(req->op.search.attrs, "allowedAttributesEffective");
344
345         ac->allowedChildClasses = ldb_attr_in_list(req->op.search.attrs, "allowedChildClasses");
346
347         ac->allowedChildClassesEffective = ldb_attr_in_list(req->op.search.attrs, "allowedChildClassesEffective");
348
349         if (ac->allowedAttributes || ac->allowedAttributesEffective || ac->allowedChildClasses || ac->allowedChildClassesEffective) {
350                 down_req->op.search.attrs
351                         = ldb_attr_list_copy_add(down_req, down_req->op.search.attrs, "objectClass");
352         }
353
354         /*  FIXME: I hink we should copy the tree and keep the original
355          *  unmodified. SSS */
356         /* replace any attributes in the parse tree that are private,
357            so we don't allow a search for 'sambaPassword=penguin',
358            just as we would not allow that attribute to be returned */
359         switch (ac->user_type) {
360         case SYSTEM:
361                 break;
362         default:
363                 /* remove password attributes */
364                 for (i = 0; data && data->password_attrs && data->password_attrs[i]; i++) {
365                         ldb_parse_tree_attr_replace(down_req->op.search.tree, 
366                                                     data->password_attrs[i],
367                                                     "kludgeACLredactedattribute");
368                 }
369         }
370
371         down_req->controls = req->controls;
372
373         down_req->context = ac;
374         down_req->callback = kludge_acl_callback;
375         ldb_set_timeout_from_prev_req(module->ldb, req, down_req);
376
377         /* perform the search */
378         ret = ldb_next_request(module, down_req);
379
380         /* do not free down_req as the call results may be linked to it,
381          * it will be freed when the upper level request get freed */
382         if (ret == LDB_SUCCESS) {
383                 req->handle = down_req->handle;
384         }
385
386         return ret;
387 }
388
389 /* ANY change type */
390 static int kludge_acl_change(struct ldb_module *module, struct ldb_request *req)
391 {
392         enum user_is user_type = what_is_user(module);
393         switch (user_type) {
394         case SYSTEM:
395         case ADMINISTRATOR:
396                 return ldb_next_request(module, req);
397         default:
398                 ldb_asprintf_errstring(module->ldb,
399                                        "kludge_acl_change: "
400                                        "attempted database modify not permitted. "
401                                        "User %s is not SYSTEM or an administrator",
402                                        user_name(req, module));
403                 return LDB_ERR_INSUFFICIENT_ACCESS_RIGHTS;
404         }
405 }
406
407 static int kludge_acl_init(struct ldb_module *module)
408 {
409         int ret, i;
410         TALLOC_CTX *mem_ctx = talloc_new(module);
411         static const char *attrs[] = { "passwordAttribute", NULL };
412         struct ldb_result *res;
413         struct ldb_message *msg;
414         struct ldb_message_element *password_attributes;
415
416         struct kludge_private_data *data;
417
418         data = talloc(module, struct kludge_private_data);
419         if (data == NULL) {
420                 return LDB_ERR_OPERATIONS_ERROR;
421         }
422
423         data->password_attrs = NULL;
424         module->private_data = data;
425
426         if (!mem_ctx) {
427                 return LDB_ERR_OPERATIONS_ERROR;
428         }
429
430         ret = ldb_search(module->ldb, ldb_dn_new(mem_ctx, module->ldb, "@KLUDGEACL"),
431                          LDB_SCOPE_BASE,
432                          NULL, attrs,
433                          &res);
434         if (ret != LDB_SUCCESS) {
435                 goto done;
436         }
437         talloc_steal(mem_ctx, res);
438         if (res->count == 0) {
439                 goto done;
440         }
441
442         if (res->count > 1) {
443                 talloc_free(mem_ctx);
444                 return LDB_ERR_CONSTRAINT_VIOLATION;
445         }
446
447         msg = res->msgs[0];
448
449         password_attributes = ldb_msg_find_element(msg, "passwordAttribute");
450         if (!password_attributes) {
451                 goto done;
452         }
453         data->password_attrs = talloc_array(data, const char *, password_attributes->num_values + 1);
454         if (!data->password_attrs) {
455                 talloc_free(mem_ctx);
456                 return LDB_ERR_OPERATIONS_ERROR;
457         }
458         for (i=0; i < password_attributes->num_values; i++) {
459                 data->password_attrs[i] = (const char *)password_attributes->values[i].data;    
460                 talloc_steal(data->password_attrs, password_attributes->values[i].data);
461         }
462         data->password_attrs[i] = NULL;
463
464 done:
465         talloc_free(mem_ctx);
466         return ldb_next_init(module);
467 }
468
469 static const struct ldb_module_ops kludge_acl_ops = {
470         .name              = "kludge_acl",
471         .search            = kludge_acl_search,
472         .add               = kludge_acl_change,
473         .modify            = kludge_acl_change,
474         .del               = kludge_acl_change,
475         .rename            = kludge_acl_change,
476         .extended          = kludge_acl_change,
477         .init_context      = kludge_acl_init
478 };
479
480 int ldb_kludge_acl_init(void)
481 {
482         return ldb_register_module(&kludge_acl_ops);
483 }