Commit | Line | Data |
---|---|---|
847b173e TH |
1 | /* |
2 | * security/tomoyo/gc.c | |
3 | * | |
4 | * Implementation of the Domain-Based Mandatory Access Control. | |
5 | * | |
6 | * Copyright (C) 2005-2010 NTT DATA CORPORATION | |
7 | * | |
8 | */ | |
9 | ||
10 | #include "common.h" | |
11 | #include <linux/kthread.h> | |
5a0e3ad6 | 12 | #include <linux/slab.h> |
847b173e | 13 | |
2e503bbb TH |
14 | /* The list for "struct tomoyo_io_buffer". */ |
15 | static LIST_HEAD(tomoyo_io_buffer_list); | |
16 | /* Lock for protecting tomoyo_io_buffer_list. */ | |
17 | static DEFINE_SPINLOCK(tomoyo_io_buffer_list_lock); | |
18 | ||
19 | /* Size of an element. */ | |
20 | static const u8 tomoyo_element_size[TOMOYO_MAX_POLICY] = { | |
21 | [TOMOYO_ID_GROUP] = sizeof(struct tomoyo_group), | |
22 | [TOMOYO_ID_PATH_GROUP] = sizeof(struct tomoyo_path_group), | |
23 | [TOMOYO_ID_NUMBER_GROUP] = sizeof(struct tomoyo_number_group), | |
24 | [TOMOYO_ID_AGGREGATOR] = sizeof(struct tomoyo_aggregator), | |
25 | [TOMOYO_ID_TRANSITION_CONTROL] = | |
26 | sizeof(struct tomoyo_transition_control), | |
27 | [TOMOYO_ID_MANAGER] = sizeof(struct tomoyo_manager), | |
2066a361 | 28 | /* [TOMOYO_ID_CONDITION] = "struct tomoyo_condition"->size, */ |
2e503bbb TH |
29 | /* [TOMOYO_ID_NAME] = "struct tomoyo_name"->size, */ |
30 | /* [TOMOYO_ID_ACL] = | |
31 | tomoyo_acl_size["struct tomoyo_acl_info"->type], */ | |
32 | [TOMOYO_ID_DOMAIN] = sizeof(struct tomoyo_domain_info), | |
33 | }; | |
34 | ||
35 | /* Size of a domain ACL element. */ | |
36 | static const u8 tomoyo_acl_size[] = { | |
37 | [TOMOYO_TYPE_PATH_ACL] = sizeof(struct tomoyo_path_acl), | |
38 | [TOMOYO_TYPE_PATH2_ACL] = sizeof(struct tomoyo_path2_acl), | |
39 | [TOMOYO_TYPE_PATH_NUMBER_ACL] = sizeof(struct tomoyo_path_number_acl), | |
40 | [TOMOYO_TYPE_MKDEV_ACL] = sizeof(struct tomoyo_mkdev_acl), | |
41 | [TOMOYO_TYPE_MOUNT_ACL] = sizeof(struct tomoyo_mount_acl), | |
42 | }; | |
43 | ||
44 | /** | |
45 | * tomoyo_struct_used_by_io_buffer - Check whether the list element is used by /sys/kernel/security/tomoyo/ users or not. | |
46 | * | |
47 | * @element: Pointer to "struct list_head". | |
48 | * | |
49 | * Returns true if @element is used by /sys/kernel/security/tomoyo/ users, | |
50 | * false otherwise. | |
51 | */ | |
52 | static bool tomoyo_struct_used_by_io_buffer(const struct list_head *element) | |
53 | { | |
54 | struct tomoyo_io_buffer *head; | |
55 | bool in_use = false; | |
56 | ||
57 | spin_lock(&tomoyo_io_buffer_list_lock); | |
58 | list_for_each_entry(head, &tomoyo_io_buffer_list, list) { | |
59 | head->users++; | |
60 | spin_unlock(&tomoyo_io_buffer_list_lock); | |
61 | if (mutex_lock_interruptible(&head->io_sem)) { | |
62 | in_use = true; | |
63 | goto out; | |
64 | } | |
65 | if (head->r.domain == element || head->r.group == element || | |
66 | head->r.acl == element || &head->w.domain->list == element) | |
67 | in_use = true; | |
68 | mutex_unlock(&head->io_sem); | |
69 | out: | |
70 | spin_lock(&tomoyo_io_buffer_list_lock); | |
71 | head->users--; | |
72 | if (in_use) | |
73 | break; | |
74 | } | |
75 | spin_unlock(&tomoyo_io_buffer_list_lock); | |
76 | return in_use; | |
77 | } | |
78 | ||
79 | /** | |
80 | * tomoyo_name_used_by_io_buffer - Check whether the string is used by /sys/kernel/security/tomoyo/ users or not. | |
81 | * | |
82 | * @string: String to check. | |
83 | * @size: Memory allocated for @string . | |
84 | * | |
85 | * Returns true if @string is used by /sys/kernel/security/tomoyo/ users, | |
86 | * false otherwise. | |
87 | */ | |
88 | static bool tomoyo_name_used_by_io_buffer(const char *string, | |
89 | const size_t size) | |
90 | { | |
91 | struct tomoyo_io_buffer *head; | |
92 | bool in_use = false; | |
93 | ||
94 | spin_lock(&tomoyo_io_buffer_list_lock); | |
95 | list_for_each_entry(head, &tomoyo_io_buffer_list, list) { | |
96 | int i; | |
97 | head->users++; | |
98 | spin_unlock(&tomoyo_io_buffer_list_lock); | |
99 | if (mutex_lock_interruptible(&head->io_sem)) { | |
100 | in_use = true; | |
101 | goto out; | |
102 | } | |
103 | for (i = 0; i < TOMOYO_MAX_IO_READ_QUEUE; i++) { | |
104 | const char *w = head->r.w[i]; | |
105 | if (w < string || w > string + size) | |
106 | continue; | |
107 | in_use = true; | |
108 | break; | |
109 | } | |
110 | mutex_unlock(&head->io_sem); | |
111 | out: | |
112 | spin_lock(&tomoyo_io_buffer_list_lock); | |
113 | head->users--; | |
114 | if (in_use) | |
115 | break; | |
116 | } | |
117 | spin_unlock(&tomoyo_io_buffer_list_lock); | |
118 | return in_use; | |
119 | } | |
120 | ||
121 | /* Structure for garbage collection. */ | |
e2bf6907 | 122 | struct tomoyo_gc { |
847b173e | 123 | struct list_head list; |
0df7e8b8 | 124 | enum tomoyo_policy_id type; |
2e503bbb | 125 | size_t size; |
e79acf0e | 126 | struct list_head *element; |
847b173e | 127 | }; |
2e503bbb TH |
128 | /* List of entries to be deleted. */ |
129 | static LIST_HEAD(tomoyo_gc_list); | |
130 | /* Length of tomoyo_gc_list. */ | |
131 | static int tomoyo_gc_list_len; | |
847b173e | 132 | |
0df7e8b8 TH |
133 | /** |
134 | * tomoyo_add_to_gc - Add an entry to to be deleted list. | |
135 | * | |
136 | * @type: One of values in "enum tomoyo_policy_id". | |
137 | * @element: Pointer to "struct list_head". | |
138 | * | |
139 | * Returns true on success, false otherwise. | |
140 | * | |
141 | * Caller holds tomoyo_policy_lock mutex. | |
142 | * | |
143 | * Adding an entry needs kmalloc(). Thus, if we try to add thousands of | |
144 | * entries at once, it will take too long time. Thus, do not add more than 128 | |
145 | * entries per a scan. But to be able to handle worst case where all entries | |
146 | * are in-use, we accept one more entry per a scan. | |
147 | * | |
148 | * If we use singly linked list using "struct list_head"->prev (which is | |
149 | * LIST_POISON2), we can avoid kmalloc(). | |
150 | */ | |
e79acf0e | 151 | static bool tomoyo_add_to_gc(const int type, struct list_head *element) |
847b173e | 152 | { |
e2bf6907 | 153 | struct tomoyo_gc *entry = kzalloc(sizeof(*entry), GFP_ATOMIC); |
847b173e TH |
154 | if (!entry) |
155 | return false; | |
156 | entry->type = type; | |
2e503bbb TH |
157 | if (type == TOMOYO_ID_ACL) |
158 | entry->size = tomoyo_acl_size[ | |
159 | container_of(element, | |
160 | typeof(struct tomoyo_acl_info), | |
161 | list)->type]; | |
162 | else if (type == TOMOYO_ID_NAME) | |
163 | entry->size = strlen(container_of(element, | |
164 | typeof(struct tomoyo_name), | |
165 | head.list)->entry.name) + 1; | |
2066a361 TH |
166 | else if (type == TOMOYO_ID_CONDITION) |
167 | entry->size = | |
168 | container_of(element, typeof(struct tomoyo_condition), | |
169 | head.list)->size; | |
2e503bbb TH |
170 | else |
171 | entry->size = tomoyo_element_size[type]; | |
847b173e | 172 | entry->element = element; |
2e503bbb | 173 | list_add(&entry->list, &tomoyo_gc_list); |
e79acf0e | 174 | list_del_rcu(element); |
2e503bbb TH |
175 | return tomoyo_gc_list_len++ < 128; |
176 | } | |
177 | ||
178 | /** | |
179 | * tomoyo_element_linked_by_gc - Validate next element of an entry. | |
180 | * | |
181 | * @element: Pointer to an element. | |
182 | * @size: Size of @element in byte. | |
183 | * | |
184 | * Returns true if @element is linked by other elements in the garbage | |
185 | * collector's queue, false otherwise. | |
186 | */ | |
187 | static bool tomoyo_element_linked_by_gc(const u8 *element, const size_t size) | |
188 | { | |
189 | struct tomoyo_gc *p; | |
190 | list_for_each_entry(p, &tomoyo_gc_list, list) { | |
191 | const u8 *ptr = (const u8 *) p->element->next; | |
192 | if (ptr < element || element + size < ptr) | |
193 | continue; | |
194 | return true; | |
195 | } | |
196 | return false; | |
847b173e TH |
197 | } |
198 | ||
0df7e8b8 TH |
199 | /** |
200 | * tomoyo_del_transition_control - Delete members in "struct tomoyo_transition_control". | |
201 | * | |
202 | * @element: Pointer to "struct list_head". | |
203 | * | |
204 | * Returns nothing. | |
205 | */ | |
5448ec4f | 206 | static void tomoyo_del_transition_control(struct list_head *element) |
847b173e | 207 | { |
5448ec4f | 208 | struct tomoyo_transition_control *ptr = |
e79acf0e | 209 | container_of(element, typeof(*ptr), head.list); |
847b173e TH |
210 | tomoyo_put_name(ptr->domainname); |
211 | tomoyo_put_name(ptr->program); | |
212 | } | |
213 | ||
0df7e8b8 TH |
214 | /** |
215 | * tomoyo_del_aggregator - Delete members in "struct tomoyo_aggregator". | |
216 | * | |
217 | * @element: Pointer to "struct list_head". | |
218 | * | |
219 | * Returns nothing. | |
220 | */ | |
e79acf0e | 221 | static void tomoyo_del_aggregator(struct list_head *element) |
1084307c | 222 | { |
e2bf6907 | 223 | struct tomoyo_aggregator *ptr = |
e79acf0e | 224 | container_of(element, typeof(*ptr), head.list); |
1084307c TH |
225 | tomoyo_put_name(ptr->original_name); |
226 | tomoyo_put_name(ptr->aggregated_name); | |
227 | } | |
228 | ||
0df7e8b8 TH |
229 | /** |
230 | * tomoyo_del_manager - Delete members in "struct tomoyo_manager". | |
231 | * | |
232 | * @element: Pointer to "struct list_head". | |
233 | * | |
234 | * Returns nothing. | |
235 | */ | |
e79acf0e | 236 | static void tomoyo_del_manager(struct list_head *element) |
847b173e | 237 | { |
e2bf6907 | 238 | struct tomoyo_manager *ptr = |
e79acf0e | 239 | container_of(element, typeof(*ptr), head.list); |
847b173e TH |
240 | tomoyo_put_name(ptr->manager); |
241 | } | |
242 | ||
0df7e8b8 TH |
243 | /** |
244 | * tomoyo_del_acl - Delete members in "struct tomoyo_acl_info". | |
245 | * | |
246 | * @element: Pointer to "struct list_head". | |
247 | * | |
248 | * Returns nothing. | |
249 | */ | |
e79acf0e | 250 | static void tomoyo_del_acl(struct list_head *element) |
847b173e | 251 | { |
e79acf0e TH |
252 | struct tomoyo_acl_info *acl = |
253 | container_of(element, typeof(*acl), list); | |
2066a361 | 254 | tomoyo_put_condition(acl->cond); |
847b173e | 255 | switch (acl->type) { |
7ef61233 | 256 | case TOMOYO_TYPE_PATH_ACL: |
847b173e | 257 | { |
7ef61233 | 258 | struct tomoyo_path_acl *entry |
847b173e | 259 | = container_of(acl, typeof(*entry), head); |
7762fbff | 260 | tomoyo_put_name_union(&entry->name); |
847b173e TH |
261 | } |
262 | break; | |
7ef61233 | 263 | case TOMOYO_TYPE_PATH2_ACL: |
847b173e | 264 | { |
7ef61233 | 265 | struct tomoyo_path2_acl *entry |
847b173e | 266 | = container_of(acl, typeof(*entry), head); |
7762fbff TH |
267 | tomoyo_put_name_union(&entry->name1); |
268 | tomoyo_put_name_union(&entry->name2); | |
847b173e TH |
269 | } |
270 | break; | |
a1f9bb6a TH |
271 | case TOMOYO_TYPE_PATH_NUMBER_ACL: |
272 | { | |
273 | struct tomoyo_path_number_acl *entry | |
274 | = container_of(acl, typeof(*entry), head); | |
275 | tomoyo_put_name_union(&entry->name); | |
276 | tomoyo_put_number_union(&entry->number); | |
277 | } | |
278 | break; | |
75093152 | 279 | case TOMOYO_TYPE_MKDEV_ACL: |
a1f9bb6a | 280 | { |
75093152 | 281 | struct tomoyo_mkdev_acl *entry |
a1f9bb6a TH |
282 | = container_of(acl, typeof(*entry), head); |
283 | tomoyo_put_name_union(&entry->name); | |
284 | tomoyo_put_number_union(&entry->mode); | |
285 | tomoyo_put_number_union(&entry->major); | |
286 | tomoyo_put_number_union(&entry->minor); | |
287 | } | |
288 | break; | |
2106ccd9 TH |
289 | case TOMOYO_TYPE_MOUNT_ACL: |
290 | { | |
291 | struct tomoyo_mount_acl *entry | |
292 | = container_of(acl, typeof(*entry), head); | |
293 | tomoyo_put_name_union(&entry->dev_name); | |
294 | tomoyo_put_name_union(&entry->dir_name); | |
295 | tomoyo_put_name_union(&entry->fs_type); | |
296 | tomoyo_put_number_union(&entry->flags); | |
297 | } | |
298 | break; | |
847b173e TH |
299 | } |
300 | } | |
301 | ||
2e503bbb TH |
302 | /** |
303 | * tomoyo_del_domain - Delete members in "struct tomoyo_domain_info". | |
304 | * | |
305 | * @element: Pointer to "struct list_head". | |
306 | * | |
307 | * Returns true if deleted, false otherwise. | |
308 | */ | |
e79acf0e | 309 | static bool tomoyo_del_domain(struct list_head *element) |
847b173e | 310 | { |
e79acf0e TH |
311 | struct tomoyo_domain_info *domain = |
312 | container_of(element, typeof(*domain), list); | |
847b173e TH |
313 | struct tomoyo_acl_info *acl; |
314 | struct tomoyo_acl_info *tmp; | |
315 | /* | |
316 | * Since we don't protect whole execve() operation using SRCU, | |
317 | * we need to recheck domain->users at this point. | |
318 | * | |
319 | * (1) Reader starts SRCU section upon execve(). | |
320 | * (2) Reader traverses tomoyo_domain_list and finds this domain. | |
321 | * (3) Writer marks this domain as deleted. | |
322 | * (4) Garbage collector removes this domain from tomoyo_domain_list | |
323 | * because this domain is marked as deleted and used by nobody. | |
324 | * (5) Reader saves reference to this domain into | |
325 | * "struct linux_binprm"->cred->security . | |
326 | * (6) Reader finishes SRCU section, although execve() operation has | |
327 | * not finished yet. | |
328 | * (7) Garbage collector waits for SRCU synchronization. | |
329 | * (8) Garbage collector kfree() this domain because this domain is | |
330 | * used by nobody. | |
331 | * (9) Reader finishes execve() operation and restores this domain from | |
332 | * "struct linux_binprm"->cred->security. | |
333 | * | |
334 | * By updating domain->users at (5), we can solve this race problem | |
335 | * by rechecking domain->users at (8). | |
336 | */ | |
337 | if (atomic_read(&domain->users)) | |
338 | return false; | |
339 | list_for_each_entry_safe(acl, tmp, &domain->acl_info_list, list) { | |
e79acf0e | 340 | tomoyo_del_acl(&acl->list); |
847b173e TH |
341 | tomoyo_memory_free(acl); |
342 | } | |
343 | tomoyo_put_name(domain->domainname); | |
344 | return true; | |
345 | } | |
346 | ||
2066a361 TH |
347 | /** |
348 | * tomoyo_del_condition - Delete members in "struct tomoyo_condition". | |
349 | * | |
350 | * @element: Pointer to "struct list_head". | |
351 | * | |
352 | * Returns nothing. | |
353 | */ | |
354 | void tomoyo_del_condition(struct list_head *element) | |
355 | { | |
356 | struct tomoyo_condition *cond = container_of(element, typeof(*cond), | |
357 | head.list); | |
358 | const u16 condc = cond->condc; | |
359 | const u16 numbers_count = cond->numbers_count; | |
360 | unsigned int i; | |
361 | const struct tomoyo_condition_element *condp | |
362 | = (const struct tomoyo_condition_element *) (cond + 1); | |
363 | struct tomoyo_number_union *numbers_p | |
364 | = (struct tomoyo_number_union *) (condp + condc); | |
365 | for (i = 0; i < numbers_count; i++) | |
366 | tomoyo_put_number_union(numbers_p++); | |
367 | } | |
847b173e | 368 | |
0df7e8b8 TH |
369 | /** |
370 | * tomoyo_del_name - Delete members in "struct tomoyo_name". | |
371 | * | |
372 | * @element: Pointer to "struct list_head". | |
373 | * | |
374 | * Returns nothing. | |
375 | */ | |
e79acf0e | 376 | static void tomoyo_del_name(struct list_head *element) |
847b173e | 377 | { |
e2bf6907 | 378 | const struct tomoyo_name *ptr = |
0df7e8b8 | 379 | container_of(element, typeof(*ptr), head.list); |
847b173e TH |
380 | } |
381 | ||
0df7e8b8 TH |
382 | /** |
383 | * tomoyo_del_path_group - Delete members in "struct tomoyo_path_group". | |
384 | * | |
385 | * @element: Pointer to "struct list_head". | |
386 | * | |
387 | * Returns nothing. | |
388 | */ | |
a98aa4de | 389 | static void tomoyo_del_path_group(struct list_head *element) |
7762fbff | 390 | { |
a98aa4de | 391 | struct tomoyo_path_group *member = |
e79acf0e | 392 | container_of(element, typeof(*member), head.list); |
7762fbff TH |
393 | tomoyo_put_name(member->member_name); |
394 | } | |
395 | ||
0df7e8b8 TH |
396 | /** |
397 | * tomoyo_del_group - Delete "struct tomoyo_group". | |
398 | * | |
399 | * @element: Pointer to "struct list_head". | |
400 | * | |
401 | * Returns nothing. | |
402 | */ | |
a98aa4de | 403 | static void tomoyo_del_group(struct list_head *element) |
7762fbff | 404 | { |
a98aa4de | 405 | struct tomoyo_group *group = |
0df7e8b8 | 406 | container_of(element, typeof(*group), head.list); |
7762fbff TH |
407 | tomoyo_put_name(group->group_name); |
408 | } | |
409 | ||
0df7e8b8 TH |
410 | /** |
411 | * tomoyo_del_number_group - Delete members in "struct tomoyo_number_group". | |
412 | * | |
413 | * @element: Pointer to "struct list_head". | |
414 | * | |
415 | * Returns nothing. | |
416 | */ | |
e79acf0e | 417 | static void tomoyo_del_number_group(struct list_head *element) |
4c3e9e2d | 418 | { |
a98aa4de TH |
419 | struct tomoyo_number_group *member = |
420 | container_of(element, typeof(*member), head.list); | |
4c3e9e2d TH |
421 | } |
422 | ||
0df7e8b8 TH |
423 | /** |
424 | * tomoyo_collect_member - Delete elements with "struct tomoyo_acl_head". | |
425 | * | |
426 | * @id: One of values in "enum tomoyo_policy_id". | |
427 | * @member_list: Pointer to "struct list_head". | |
428 | * | |
429 | * Returns true if some elements are deleted, false otherwise. | |
430 | */ | |
431 | static bool tomoyo_collect_member(const enum tomoyo_policy_id id, | |
432 | struct list_head *member_list) | |
d2f8b234 TH |
433 | { |
434 | struct tomoyo_acl_head *member; | |
435 | list_for_each_entry(member, member_list, list) { | |
436 | if (!member->is_deleted) | |
437 | continue; | |
438 | if (!tomoyo_add_to_gc(id, &member->list)) | |
439 | return false; | |
d2f8b234 TH |
440 | } |
441 | return true; | |
442 | } | |
443 | ||
32997144 TH |
444 | /** |
445 | * tomoyo_collect_acl - Delete elements in "struct tomoyo_domain_info". | |
446 | * | |
447 | * @list: Pointer to "struct list_head". | |
448 | * | |
449 | * Returns true if some elements are deleted, false otherwise. | |
450 | */ | |
451 | static bool tomoyo_collect_acl(struct list_head *list) | |
d2f8b234 TH |
452 | { |
453 | struct tomoyo_acl_info *acl; | |
32997144 | 454 | list_for_each_entry(acl, list, list) { |
d2f8b234 TH |
455 | if (!acl->is_deleted) |
456 | continue; | |
457 | if (!tomoyo_add_to_gc(TOMOYO_ID_ACL, &acl->list)) | |
458 | return false; | |
d2f8b234 TH |
459 | } |
460 | return true; | |
461 | } | |
462 | ||
0df7e8b8 TH |
463 | /** |
464 | * tomoyo_collect_entry - Scan lists for deleted elements. | |
465 | * | |
466 | * Returns nothing. | |
467 | */ | |
847b173e TH |
468 | static void tomoyo_collect_entry(void) |
469 | { | |
d2f8b234 | 470 | int i; |
bd03a3e4 TH |
471 | enum tomoyo_policy_id id; |
472 | struct tomoyo_policy_namespace *ns; | |
473 | int idx; | |
29282381 TH |
474 | if (mutex_lock_interruptible(&tomoyo_policy_lock)) |
475 | return; | |
bd03a3e4 | 476 | idx = tomoyo_read_lock(); |
847b173e TH |
477 | { |
478 | struct tomoyo_domain_info *domain; | |
479 | list_for_each_entry_rcu(domain, &tomoyo_domain_list, list) { | |
32997144 | 480 | if (!tomoyo_collect_acl(&domain->acl_info_list)) |
d2f8b234 | 481 | goto unlock; |
847b173e TH |
482 | if (!domain->is_deleted || atomic_read(&domain->users)) |
483 | continue; | |
484 | /* | |
485 | * Nobody is referring this domain. But somebody may | |
486 | * refer this domain after successful execve(). | |
487 | * We recheck domain->users after SRCU synchronization. | |
488 | */ | |
e79acf0e | 489 | if (!tomoyo_add_to_gc(TOMOYO_ID_DOMAIN, &domain->list)) |
d2f8b234 | 490 | goto unlock; |
847b173e TH |
491 | } |
492 | } | |
bd03a3e4 TH |
493 | list_for_each_entry_rcu(ns, &tomoyo_namespace_list, namespace_list) { |
494 | for (id = 0; id < TOMOYO_MAX_POLICY; id++) | |
495 | if (!tomoyo_collect_member(id, &ns->policy_list[id])) | |
d2f8b234 | 496 | goto unlock; |
bd03a3e4 TH |
497 | for (i = 0; i < TOMOYO_MAX_ACL_GROUPS; i++) |
498 | if (!tomoyo_collect_acl(&ns->acl_group[i])) | |
499 | goto unlock; | |
500 | for (i = 0; i < TOMOYO_MAX_GROUP; i++) { | |
501 | struct list_head *list = &ns->group_list[i]; | |
502 | struct tomoyo_group *group; | |
503 | switch (i) { | |
504 | case 0: | |
505 | id = TOMOYO_ID_PATH_GROUP; | |
506 | break; | |
507 | default: | |
508 | id = TOMOYO_ID_NUMBER_GROUP; | |
509 | break; | |
510 | } | |
511 | list_for_each_entry(group, list, head.list) { | |
512 | if (!tomoyo_collect_member | |
513 | (id, &group->member_list)) | |
514 | goto unlock; | |
515 | if (!list_empty(&group->member_list) || | |
516 | atomic_read(&group->head.users)) | |
517 | continue; | |
518 | if (!tomoyo_add_to_gc(TOMOYO_ID_GROUP, | |
519 | &group->head.list)) | |
520 | goto unlock; | |
521 | } | |
847b173e TH |
522 | } |
523 | } | |
2066a361 TH |
524 | id = TOMOYO_ID_CONDITION; |
525 | for (i = 0; i < TOMOYO_MAX_HASH + 1; i++) { | |
526 | struct list_head *list = !i ? | |
527 | &tomoyo_condition_list : &tomoyo_name_list[i - 1]; | |
bd03a3e4 TH |
528 | struct tomoyo_shared_acl_head *ptr; |
529 | list_for_each_entry(ptr, list, list) { | |
530 | if (atomic_read(&ptr->users)) | |
4c3e9e2d | 531 | continue; |
2066a361 | 532 | if (!tomoyo_add_to_gc(id, &ptr->list)) |
d2f8b234 | 533 | goto unlock; |
4c3e9e2d | 534 | } |
2066a361 | 535 | id = TOMOYO_ID_NAME; |
4c3e9e2d | 536 | } |
bd03a3e4 TH |
537 | unlock: |
538 | tomoyo_read_unlock(idx); | |
29282381 | 539 | mutex_unlock(&tomoyo_policy_lock); |
847b173e TH |
540 | } |
541 | ||
2e503bbb TH |
542 | /** |
543 | * tomoyo_kfree_entry - Delete entries in tomoyo_gc_list. | |
544 | * | |
545 | * Returns true if some entries were kfree()d, false otherwise. | |
546 | */ | |
547 | static bool tomoyo_kfree_entry(void) | |
847b173e | 548 | { |
e2bf6907 TH |
549 | struct tomoyo_gc *p; |
550 | struct tomoyo_gc *tmp; | |
2e503bbb | 551 | bool result = false; |
847b173e | 552 | |
2e503bbb | 553 | list_for_each_entry_safe(p, tmp, &tomoyo_gc_list, list) { |
e79acf0e | 554 | struct list_head *element = p->element; |
2e503bbb TH |
555 | |
556 | /* | |
557 | * list_del_rcu() in tomoyo_add_to_gc() guarantees that the | |
558 | * list element became no longer reachable from the list which | |
559 | * the element was originally on (e.g. tomoyo_domain_list). | |
560 | * Also, synchronize_srcu() in tomoyo_gc_thread() guarantees | |
561 | * that the list element became no longer referenced by syscall | |
562 | * users. | |
563 | * | |
564 | * However, there are three users which may still be using the | |
565 | * list element. We need to defer until all of these users | |
566 | * forget the list element. | |
567 | * | |
568 | * Firstly, defer until "struct tomoyo_io_buffer"->r.{domain, | |
569 | * group,acl} and "struct tomoyo_io_buffer"->w.domain forget | |
570 | * the list element. | |
571 | */ | |
572 | if (tomoyo_struct_used_by_io_buffer(element)) | |
573 | continue; | |
574 | /* | |
575 | * Secondly, defer until all other elements in the | |
576 | * tomoyo_gc_list list forget the list element. | |
577 | */ | |
578 | if (tomoyo_element_linked_by_gc((const u8 *) element, p->size)) | |
579 | continue; | |
847b173e | 580 | switch (p->type) { |
5448ec4f TH |
581 | case TOMOYO_ID_TRANSITION_CONTROL: |
582 | tomoyo_del_transition_control(element); | |
847b173e | 583 | break; |
1084307c | 584 | case TOMOYO_ID_AGGREGATOR: |
e79acf0e | 585 | tomoyo_del_aggregator(element); |
1084307c | 586 | break; |
847b173e | 587 | case TOMOYO_ID_MANAGER: |
e79acf0e | 588 | tomoyo_del_manager(element); |
847b173e | 589 | break; |
2066a361 TH |
590 | case TOMOYO_ID_CONDITION: |
591 | tomoyo_del_condition(element); | |
592 | break; | |
847b173e | 593 | case TOMOYO_ID_NAME: |
2e503bbb TH |
594 | /* |
595 | * Thirdly, defer until all "struct tomoyo_io_buffer" | |
596 | * ->r.w[] forget the list element. | |
597 | */ | |
598 | if (tomoyo_name_used_by_io_buffer( | |
599 | container_of(element, typeof(struct tomoyo_name), | |
600 | head.list)->entry.name, p->size)) | |
601 | continue; | |
e79acf0e | 602 | tomoyo_del_name(element); |
847b173e TH |
603 | break; |
604 | case TOMOYO_ID_ACL: | |
e79acf0e | 605 | tomoyo_del_acl(element); |
847b173e TH |
606 | break; |
607 | case TOMOYO_ID_DOMAIN: | |
e79acf0e | 608 | if (!tomoyo_del_domain(element)) |
847b173e TH |
609 | continue; |
610 | break; | |
7762fbff | 611 | case TOMOYO_ID_PATH_GROUP: |
e79acf0e | 612 | tomoyo_del_path_group(element); |
7762fbff | 613 | break; |
a98aa4de TH |
614 | case TOMOYO_ID_GROUP: |
615 | tomoyo_del_group(element); | |
4c3e9e2d TH |
616 | break; |
617 | case TOMOYO_ID_NUMBER_GROUP: | |
e79acf0e | 618 | tomoyo_del_number_group(element); |
847b173e | 619 | break; |
0df7e8b8 TH |
620 | case TOMOYO_MAX_POLICY: |
621 | break; | |
847b173e | 622 | } |
e79acf0e | 623 | tomoyo_memory_free(element); |
847b173e TH |
624 | list_del(&p->list); |
625 | kfree(p); | |
2e503bbb TH |
626 | tomoyo_gc_list_len--; |
627 | result = true; | |
847b173e | 628 | } |
2e503bbb | 629 | return result; |
847b173e TH |
630 | } |
631 | ||
0df7e8b8 TH |
632 | /** |
633 | * tomoyo_gc_thread - Garbage collector thread function. | |
634 | * | |
635 | * @unused: Unused. | |
636 | * | |
637 | * In case OOM-killer choose this thread for termination, we create this thread | |
638 | * as a short live thread whenever /sys/kernel/security/tomoyo/ interface was | |
639 | * close()d. | |
640 | * | |
641 | * Returns 0. | |
642 | */ | |
847b173e TH |
643 | static int tomoyo_gc_thread(void *unused) |
644 | { | |
2e503bbb TH |
645 | /* Garbage collector thread is exclusive. */ |
646 | static DEFINE_MUTEX(tomoyo_gc_mutex); | |
647 | if (!mutex_trylock(&tomoyo_gc_mutex)) | |
648 | goto out; | |
847b173e | 649 | daemonize("GC for TOMOYO"); |
2e503bbb TH |
650 | do { |
651 | tomoyo_collect_entry(); | |
652 | if (list_empty(&tomoyo_gc_list)) | |
653 | break; | |
654 | synchronize_srcu(&tomoyo_ss); | |
655 | } while (tomoyo_kfree_entry()); | |
656 | { | |
657 | struct tomoyo_io_buffer *head; | |
658 | struct tomoyo_io_buffer *tmp; | |
659 | ||
660 | spin_lock(&tomoyo_io_buffer_list_lock); | |
661 | list_for_each_entry_safe(head, tmp, &tomoyo_io_buffer_list, | |
662 | list) { | |
663 | if (head->users) | |
664 | continue; | |
665 | list_del(&head->list); | |
666 | kfree(head->read_buf); | |
667 | kfree(head->write_buf); | |
668 | kfree(head); | |
847b173e | 669 | } |
2e503bbb | 670 | spin_unlock(&tomoyo_io_buffer_list_lock); |
847b173e | 671 | } |
2e503bbb TH |
672 | mutex_unlock(&tomoyo_gc_mutex); |
673 | out: | |
674 | /* This acts as do_exit(0). */ | |
675 | return 0; | |
847b173e TH |
676 | } |
677 | ||
2e503bbb TH |
678 | /** |
679 | * tomoyo_notify_gc - Register/unregister /sys/kernel/security/tomoyo/ users. | |
680 | * | |
681 | * @head: Pointer to "struct tomoyo_io_buffer". | |
682 | * @is_register: True if register, false if unregister. | |
683 | * | |
684 | * Returns nothing. | |
685 | */ | |
686 | void tomoyo_notify_gc(struct tomoyo_io_buffer *head, const bool is_register) | |
847b173e | 687 | { |
2e503bbb TH |
688 | bool is_write = false; |
689 | ||
690 | spin_lock(&tomoyo_io_buffer_list_lock); | |
691 | if (is_register) { | |
692 | head->users = 1; | |
693 | list_add(&head->list, &tomoyo_io_buffer_list); | |
694 | } else { | |
695 | is_write = head->write_buf != NULL; | |
696 | if (!--head->users) { | |
697 | list_del(&head->list); | |
698 | kfree(head->read_buf); | |
699 | kfree(head->write_buf); | |
700 | kfree(head); | |
701 | } | |
702 | } | |
703 | spin_unlock(&tomoyo_io_buffer_list_lock); | |
704 | if (is_write) { | |
705 | struct task_struct *task = kthread_create(tomoyo_gc_thread, | |
706 | NULL, | |
707 | "GC for TOMOYO"); | |
708 | if (!IS_ERR(task)) | |
709 | wake_up_process(task); | |
710 | } | |
847b173e | 711 | } |