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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * security/tomoyo/gc.c
4 *
5 * Copyright (C) 2005-2011 NTT DATA CORPORATION
6 */
7
8#include "common.h"
9#include <linux/kthread.h>
10#include <linux/slab.h>
11
12/**
13 * tomoyo_memory_free - Free memory for elements.
14 *
15 * @ptr: Pointer to allocated memory.
16 *
17 * Returns nothing.
18 *
19 * Caller holds tomoyo_policy_lock mutex.
20 */
21static inline void tomoyo_memory_free(void *ptr)
22{
23 tomoyo_memory_used[TOMOYO_MEMORY_POLICY] -= ksize(ptr);
24 kfree(ptr);
25}
26
27/* The list for "struct tomoyo_io_buffer". */
28static LIST_HEAD(tomoyo_io_buffer_list);
29/* Lock for protecting tomoyo_io_buffer_list. */
30static DEFINE_SPINLOCK(tomoyo_io_buffer_list_lock);
31
32/**
33 * tomoyo_struct_used_by_io_buffer - Check whether the list element is used by /sys/kernel/security/tomoyo/ users or not.
34 *
35 * @element: Pointer to "struct list_head".
36 *
37 * Returns true if @element is used by /sys/kernel/security/tomoyo/ users,
38 * false otherwise.
39 */
40static bool tomoyo_struct_used_by_io_buffer(const struct list_head *element)
41{
42 struct tomoyo_io_buffer *head;
43 bool in_use = false;
44
45 spin_lock(&tomoyo_io_buffer_list_lock);
46 list_for_each_entry(head, &tomoyo_io_buffer_list, list) {
47 head->users++;
48 spin_unlock(&tomoyo_io_buffer_list_lock);
49 mutex_lock(&head->io_sem);
50 if (head->r.domain == element || head->r.group == element ||
51 head->r.acl == element || &head->w.domain->list == element)
52 in_use = true;
53 mutex_unlock(&head->io_sem);
54 spin_lock(&tomoyo_io_buffer_list_lock);
55 head->users--;
56 if (in_use)
57 break;
58 }
59 spin_unlock(&tomoyo_io_buffer_list_lock);
60 return in_use;
61}
62
63/**
64 * tomoyo_name_used_by_io_buffer - Check whether the string is used by /sys/kernel/security/tomoyo/ users or not.
65 *
66 * @string: String to check.
67 *
68 * Returns true if @string is used by /sys/kernel/security/tomoyo/ users,
69 * false otherwise.
70 */
71static bool tomoyo_name_used_by_io_buffer(const char *string)
72{
73 struct tomoyo_io_buffer *head;
74 const size_t size = strlen(string) + 1;
75 bool in_use = false;
76
77 spin_lock(&tomoyo_io_buffer_list_lock);
78 list_for_each_entry(head, &tomoyo_io_buffer_list, list) {
79 int i;
80
81 head->users++;
82 spin_unlock(&tomoyo_io_buffer_list_lock);
83 mutex_lock(&head->io_sem);
84 for (i = 0; i < TOMOYO_MAX_IO_READ_QUEUE; i++) {
85 const char *w = head->r.w[i];
86
87 if (w < string || w > string + size)
88 continue;
89 in_use = true;
90 break;
91 }
92 mutex_unlock(&head->io_sem);
93 spin_lock(&tomoyo_io_buffer_list_lock);
94 head->users--;
95 if (in_use)
96 break;
97 }
98 spin_unlock(&tomoyo_io_buffer_list_lock);
99 return in_use;
100}
101
102/**
103 * tomoyo_del_transition_control - Delete members in "struct tomoyo_transition_control".
104 *
105 * @element: Pointer to "struct list_head".
106 *
107 * Returns nothing.
108 */
109static inline void tomoyo_del_transition_control(struct list_head *element)
110{
111 struct tomoyo_transition_control *ptr =
112 container_of(element, typeof(*ptr), head.list);
113
114 tomoyo_put_name(ptr->domainname);
115 tomoyo_put_name(ptr->program);
116}
117
118/**
119 * tomoyo_del_aggregator - Delete members in "struct tomoyo_aggregator".
120 *
121 * @element: Pointer to "struct list_head".
122 *
123 * Returns nothing.
124 */
125static inline void tomoyo_del_aggregator(struct list_head *element)
126{
127 struct tomoyo_aggregator *ptr =
128 container_of(element, typeof(*ptr), head.list);
129
130 tomoyo_put_name(ptr->original_name);
131 tomoyo_put_name(ptr->aggregated_name);
132}
133
134/**
135 * tomoyo_del_manager - Delete members in "struct tomoyo_manager".
136 *
137 * @element: Pointer to "struct list_head".
138 *
139 * Returns nothing.
140 */
141static inline void tomoyo_del_manager(struct list_head *element)
142{
143 struct tomoyo_manager *ptr =
144 container_of(element, typeof(*ptr), head.list);
145
146 tomoyo_put_name(ptr->manager);
147}
148
149/**
150 * tomoyo_del_acl - Delete members in "struct tomoyo_acl_info".
151 *
152 * @element: Pointer to "struct list_head".
153 *
154 * Returns nothing.
155 */
156static void tomoyo_del_acl(struct list_head *element)
157{
158 struct tomoyo_acl_info *acl =
159 container_of(element, typeof(*acl), list);
160
161 tomoyo_put_condition(acl->cond);
162 switch (acl->type) {
163 case TOMOYO_TYPE_PATH_ACL:
164 {
165 struct tomoyo_path_acl *entry
166 = container_of(acl, typeof(*entry), head);
167 tomoyo_put_name_union(&entry->name);
168 }
169 break;
170 case TOMOYO_TYPE_PATH2_ACL:
171 {
172 struct tomoyo_path2_acl *entry
173 = container_of(acl, typeof(*entry), head);
174 tomoyo_put_name_union(&entry->name1);
175 tomoyo_put_name_union(&entry->name2);
176 }
177 break;
178 case TOMOYO_TYPE_PATH_NUMBER_ACL:
179 {
180 struct tomoyo_path_number_acl *entry
181 = container_of(acl, typeof(*entry), head);
182 tomoyo_put_name_union(&entry->name);
183 tomoyo_put_number_union(&entry->number);
184 }
185 break;
186 case TOMOYO_TYPE_MKDEV_ACL:
187 {
188 struct tomoyo_mkdev_acl *entry
189 = container_of(acl, typeof(*entry), head);
190 tomoyo_put_name_union(&entry->name);
191 tomoyo_put_number_union(&entry->mode);
192 tomoyo_put_number_union(&entry->major);
193 tomoyo_put_number_union(&entry->minor);
194 }
195 break;
196 case TOMOYO_TYPE_MOUNT_ACL:
197 {
198 struct tomoyo_mount_acl *entry
199 = container_of(acl, typeof(*entry), head);
200 tomoyo_put_name_union(&entry->dev_name);
201 tomoyo_put_name_union(&entry->dir_name);
202 tomoyo_put_name_union(&entry->fs_type);
203 tomoyo_put_number_union(&entry->flags);
204 }
205 break;
206 case TOMOYO_TYPE_ENV_ACL:
207 {
208 struct tomoyo_env_acl *entry =
209 container_of(acl, typeof(*entry), head);
210
211 tomoyo_put_name(entry->env);
212 }
213 break;
214 case TOMOYO_TYPE_INET_ACL:
215 {
216 struct tomoyo_inet_acl *entry =
217 container_of(acl, typeof(*entry), head);
218
219 tomoyo_put_group(entry->address.group);
220 tomoyo_put_number_union(&entry->port);
221 }
222 break;
223 case TOMOYO_TYPE_UNIX_ACL:
224 {
225 struct tomoyo_unix_acl *entry =
226 container_of(acl, typeof(*entry), head);
227
228 tomoyo_put_name_union(&entry->name);
229 }
230 break;
231 case TOMOYO_TYPE_MANUAL_TASK_ACL:
232 {
233 struct tomoyo_task_acl *entry =
234 container_of(acl, typeof(*entry), head);
235
236 tomoyo_put_name(entry->domainname);
237 }
238 break;
239 }
240}
241
242/**
243 * tomoyo_del_domain - Delete members in "struct tomoyo_domain_info".
244 *
245 * @element: Pointer to "struct list_head".
246 *
247 * Returns nothing.
248 *
249 * Caller holds tomoyo_policy_lock mutex.
250 */
251static inline void tomoyo_del_domain(struct list_head *element)
252{
253 struct tomoyo_domain_info *domain =
254 container_of(element, typeof(*domain), list);
255 struct tomoyo_acl_info *acl;
256 struct tomoyo_acl_info *tmp;
257
258 /*
259 * Since this domain is referenced from neither
260 * "struct tomoyo_io_buffer" nor "struct cred"->security, we can delete
261 * elements without checking for is_deleted flag.
262 */
263 list_for_each_entry_safe(acl, tmp, &domain->acl_info_list, list) {
264 tomoyo_del_acl(&acl->list);
265 tomoyo_memory_free(acl);
266 }
267 tomoyo_put_name(domain->domainname);
268}
269
270/**
271 * tomoyo_del_condition - Delete members in "struct tomoyo_condition".
272 *
273 * @element: Pointer to "struct list_head".
274 *
275 * Returns nothing.
276 */
277void tomoyo_del_condition(struct list_head *element)
278{
279 struct tomoyo_condition *cond = container_of(element, typeof(*cond),
280 head.list);
281 const u16 condc = cond->condc;
282 const u16 numbers_count = cond->numbers_count;
283 const u16 names_count = cond->names_count;
284 const u16 argc = cond->argc;
285 const u16 envc = cond->envc;
286 unsigned int i;
287 const struct tomoyo_condition_element *condp
288 = (const struct tomoyo_condition_element *) (cond + 1);
289 struct tomoyo_number_union *numbers_p
290 = (struct tomoyo_number_union *) (condp + condc);
291 struct tomoyo_name_union *names_p
292 = (struct tomoyo_name_union *) (numbers_p + numbers_count);
293 const struct tomoyo_argv *argv
294 = (const struct tomoyo_argv *) (names_p + names_count);
295 const struct tomoyo_envp *envp
296 = (const struct tomoyo_envp *) (argv + argc);
297
298 for (i = 0; i < numbers_count; i++)
299 tomoyo_put_number_union(numbers_p++);
300 for (i = 0; i < names_count; i++)
301 tomoyo_put_name_union(names_p++);
302 for (i = 0; i < argc; argv++, i++)
303 tomoyo_put_name(argv->value);
304 for (i = 0; i < envc; envp++, i++) {
305 tomoyo_put_name(envp->name);
306 tomoyo_put_name(envp->value);
307 }
308}
309
310/**
311 * tomoyo_del_name - Delete members in "struct tomoyo_name".
312 *
313 * @element: Pointer to "struct list_head".
314 *
315 * Returns nothing.
316 */
317static inline void tomoyo_del_name(struct list_head *element)
318{
319 /* Nothing to do. */
320}
321
322/**
323 * tomoyo_del_path_group - Delete members in "struct tomoyo_path_group".
324 *
325 * @element: Pointer to "struct list_head".
326 *
327 * Returns nothing.
328 */
329static inline void tomoyo_del_path_group(struct list_head *element)
330{
331 struct tomoyo_path_group *member =
332 container_of(element, typeof(*member), head.list);
333
334 tomoyo_put_name(member->member_name);
335}
336
337/**
338 * tomoyo_del_group - Delete "struct tomoyo_group".
339 *
340 * @element: Pointer to "struct list_head".
341 *
342 * Returns nothing.
343 */
344static inline void tomoyo_del_group(struct list_head *element)
345{
346 struct tomoyo_group *group =
347 container_of(element, typeof(*group), head.list);
348
349 tomoyo_put_name(group->group_name);
350}
351
352/**
353 * tomoyo_del_address_group - Delete members in "struct tomoyo_address_group".
354 *
355 * @element: Pointer to "struct list_head".
356 *
357 * Returns nothing.
358 */
359static inline void tomoyo_del_address_group(struct list_head *element)
360{
361 /* Nothing to do. */
362}
363
364/**
365 * tomoyo_del_number_group - Delete members in "struct tomoyo_number_group".
366 *
367 * @element: Pointer to "struct list_head".
368 *
369 * Returns nothing.
370 */
371static inline void tomoyo_del_number_group(struct list_head *element)
372{
373 /* Nothing to do. */
374}
375
376/**
377 * tomoyo_try_to_gc - Try to kfree() an entry.
378 *
379 * @type: One of values in "enum tomoyo_policy_id".
380 * @element: Pointer to "struct list_head".
381 *
382 * Returns nothing.
383 *
384 * Caller holds tomoyo_policy_lock mutex.
385 */
386static void tomoyo_try_to_gc(const enum tomoyo_policy_id type,
387 struct list_head *element)
388{
389 /*
390 * __list_del_entry() guarantees that the list element became no longer
391 * reachable from the list which the element was originally on (e.g.
392 * tomoyo_domain_list). Also, synchronize_srcu() guarantees that the
393 * list element became no longer referenced by syscall users.
394 */
395 __list_del_entry(element);
396 mutex_unlock(&tomoyo_policy_lock);
397 synchronize_srcu(&tomoyo_ss);
398 /*
399 * However, there are two users which may still be using the list
400 * element. We need to defer until both users forget this element.
401 *
402 * Don't kfree() until "struct tomoyo_io_buffer"->r.{domain,group,acl}
403 * and "struct tomoyo_io_buffer"->w.domain forget this element.
404 */
405 if (tomoyo_struct_used_by_io_buffer(element))
406 goto reinject;
407 switch (type) {
408 case TOMOYO_ID_TRANSITION_CONTROL:
409 tomoyo_del_transition_control(element);
410 break;
411 case TOMOYO_ID_MANAGER:
412 tomoyo_del_manager(element);
413 break;
414 case TOMOYO_ID_AGGREGATOR:
415 tomoyo_del_aggregator(element);
416 break;
417 case TOMOYO_ID_GROUP:
418 tomoyo_del_group(element);
419 break;
420 case TOMOYO_ID_PATH_GROUP:
421 tomoyo_del_path_group(element);
422 break;
423 case TOMOYO_ID_ADDRESS_GROUP:
424 tomoyo_del_address_group(element);
425 break;
426 case TOMOYO_ID_NUMBER_GROUP:
427 tomoyo_del_number_group(element);
428 break;
429 case TOMOYO_ID_CONDITION:
430 tomoyo_del_condition(element);
431 break;
432 case TOMOYO_ID_NAME:
433 /*
434 * Don't kfree() until all "struct tomoyo_io_buffer"->r.w[]
435 * forget this element.
436 */
437 if (tomoyo_name_used_by_io_buffer
438 (container_of(element, typeof(struct tomoyo_name),
439 head.list)->entry.name))
440 goto reinject;
441 tomoyo_del_name(element);
442 break;
443 case TOMOYO_ID_ACL:
444 tomoyo_del_acl(element);
445 break;
446 case TOMOYO_ID_DOMAIN:
447 /*
448 * Don't kfree() until all "struct cred"->security forget this
449 * element.
450 */
451 if (atomic_read(&container_of
452 (element, typeof(struct tomoyo_domain_info),
453 list)->users))
454 goto reinject;
455 break;
456 case TOMOYO_MAX_POLICY:
457 break;
458 }
459 mutex_lock(&tomoyo_policy_lock);
460 if (type == TOMOYO_ID_DOMAIN)
461 tomoyo_del_domain(element);
462 tomoyo_memory_free(element);
463 return;
464reinject:
465 /*
466 * We can safely reinject this element here because
467 * (1) Appending list elements and removing list elements are protected
468 * by tomoyo_policy_lock mutex.
469 * (2) Only this function removes list elements and this function is
470 * exclusively executed by tomoyo_gc_mutex mutex.
471 * are true.
472 */
473 mutex_lock(&tomoyo_policy_lock);
474 list_add_rcu(element, element->prev);
475}
476
477/**
478 * tomoyo_collect_member - Delete elements with "struct tomoyo_acl_head".
479 *
480 * @id: One of values in "enum tomoyo_policy_id".
481 * @member_list: Pointer to "struct list_head".
482 *
483 * Returns nothing.
484 */
485static void tomoyo_collect_member(const enum tomoyo_policy_id id,
486 struct list_head *member_list)
487{
488 struct tomoyo_acl_head *member;
489 struct tomoyo_acl_head *tmp;
490
491 list_for_each_entry_safe(member, tmp, member_list, list) {
492 if (!member->is_deleted)
493 continue;
494 member->is_deleted = TOMOYO_GC_IN_PROGRESS;
495 tomoyo_try_to_gc(id, &member->list);
496 }
497}
498
499/**
500 * tomoyo_collect_acl - Delete elements in "struct tomoyo_domain_info".
501 *
502 * @list: Pointer to "struct list_head".
503 *
504 * Returns nothing.
505 */
506static void tomoyo_collect_acl(struct list_head *list)
507{
508 struct tomoyo_acl_info *acl;
509 struct tomoyo_acl_info *tmp;
510
511 list_for_each_entry_safe(acl, tmp, list, list) {
512 if (!acl->is_deleted)
513 continue;
514 acl->is_deleted = TOMOYO_GC_IN_PROGRESS;
515 tomoyo_try_to_gc(TOMOYO_ID_ACL, &acl->list);
516 }
517}
518
519/**
520 * tomoyo_collect_entry - Try to kfree() deleted elements.
521 *
522 * Returns nothing.
523 */
524static void tomoyo_collect_entry(void)
525{
526 int i;
527 enum tomoyo_policy_id id;
528 struct tomoyo_policy_namespace *ns;
529
530 mutex_lock(&tomoyo_policy_lock);
531 {
532 struct tomoyo_domain_info *domain;
533 struct tomoyo_domain_info *tmp;
534
535 list_for_each_entry_safe(domain, tmp, &tomoyo_domain_list,
536 list) {
537 tomoyo_collect_acl(&domain->acl_info_list);
538 if (!domain->is_deleted || atomic_read(&domain->users))
539 continue;
540 tomoyo_try_to_gc(TOMOYO_ID_DOMAIN, &domain->list);
541 }
542 }
543 list_for_each_entry(ns, &tomoyo_namespace_list, namespace_list) {
544 for (id = 0; id < TOMOYO_MAX_POLICY; id++)
545 tomoyo_collect_member(id, &ns->policy_list[id]);
546 for (i = 0; i < TOMOYO_MAX_ACL_GROUPS; i++)
547 tomoyo_collect_acl(&ns->acl_group[i]);
548 }
549 {
550 struct tomoyo_shared_acl_head *ptr;
551 struct tomoyo_shared_acl_head *tmp;
552
553 list_for_each_entry_safe(ptr, tmp, &tomoyo_condition_list,
554 list) {
555 if (atomic_read(&ptr->users) > 0)
556 continue;
557 atomic_set(&ptr->users, TOMOYO_GC_IN_PROGRESS);
558 tomoyo_try_to_gc(TOMOYO_ID_CONDITION, &ptr->list);
559 }
560 }
561 list_for_each_entry(ns, &tomoyo_namespace_list, namespace_list) {
562 for (i = 0; i < TOMOYO_MAX_GROUP; i++) {
563 struct list_head *list = &ns->group_list[i];
564 struct tomoyo_group *group;
565 struct tomoyo_group *tmp;
566
567 switch (i) {
568 case 0:
569 id = TOMOYO_ID_PATH_GROUP;
570 break;
571 case 1:
572 id = TOMOYO_ID_NUMBER_GROUP;
573 break;
574 default:
575 id = TOMOYO_ID_ADDRESS_GROUP;
576 break;
577 }
578 list_for_each_entry_safe(group, tmp, list, head.list) {
579 tomoyo_collect_member(id, &group->member_list);
580 if (!list_empty(&group->member_list) ||
581 atomic_read(&group->head.users) > 0)
582 continue;
583 atomic_set(&group->head.users,
584 TOMOYO_GC_IN_PROGRESS);
585 tomoyo_try_to_gc(TOMOYO_ID_GROUP,
586 &group->head.list);
587 }
588 }
589 }
590 for (i = 0; i < TOMOYO_MAX_HASH; i++) {
591 struct list_head *list = &tomoyo_name_list[i];
592 struct tomoyo_shared_acl_head *ptr;
593 struct tomoyo_shared_acl_head *tmp;
594
595 list_for_each_entry_safe(ptr, tmp, list, list) {
596 if (atomic_read(&ptr->users) > 0)
597 continue;
598 atomic_set(&ptr->users, TOMOYO_GC_IN_PROGRESS);
599 tomoyo_try_to_gc(TOMOYO_ID_NAME, &ptr->list);
600 }
601 }
602 mutex_unlock(&tomoyo_policy_lock);
603}
604
605/**
606 * tomoyo_gc_thread - Garbage collector thread function.
607 *
608 * @unused: Unused.
609 *
610 * Returns 0.
611 */
612static int tomoyo_gc_thread(void *unused)
613{
614 /* Garbage collector thread is exclusive. */
615 static DEFINE_MUTEX(tomoyo_gc_mutex);
616
617 if (!mutex_trylock(&tomoyo_gc_mutex))
618 goto out;
619 tomoyo_collect_entry();
620 {
621 struct tomoyo_io_buffer *head;
622 struct tomoyo_io_buffer *tmp;
623
624 spin_lock(&tomoyo_io_buffer_list_lock);
625 list_for_each_entry_safe(head, tmp, &tomoyo_io_buffer_list,
626 list) {
627 if (head->users)
628 continue;
629 list_del(&head->list);
630 kfree(head->read_buf);
631 kfree(head->write_buf);
632 kfree(head);
633 }
634 spin_unlock(&tomoyo_io_buffer_list_lock);
635 }
636 mutex_unlock(&tomoyo_gc_mutex);
637out:
638 /* This acts as do_exit(0). */
639 return 0;
640}
641
642/**
643 * tomoyo_notify_gc - Register/unregister /sys/kernel/security/tomoyo/ users.
644 *
645 * @head: Pointer to "struct tomoyo_io_buffer".
646 * @is_register: True if register, false if unregister.
647 *
648 * Returns nothing.
649 */
650void tomoyo_notify_gc(struct tomoyo_io_buffer *head, const bool is_register)
651{
652 bool is_write = false;
653
654 spin_lock(&tomoyo_io_buffer_list_lock);
655 if (is_register) {
656 head->users = 1;
657 list_add(&head->list, &tomoyo_io_buffer_list);
658 } else {
659 is_write = head->write_buf != NULL;
660 if (!--head->users) {
661 list_del(&head->list);
662 kfree(head->read_buf);
663 kfree(head->write_buf);
664 kfree(head);
665 }
666 }
667 spin_unlock(&tomoyo_io_buffer_list_lock);
668 if (is_write)
669 kthread_run(tomoyo_gc_thread, NULL, "GC for TOMOYO");
670}
1/*
2 * security/tomoyo/gc.c
3 *
4 * Copyright (C) 2005-2011 NTT DATA CORPORATION
5 */
6
7#include "common.h"
8#include <linux/kthread.h>
9#include <linux/slab.h>
10
11/* The list for "struct tomoyo_io_buffer". */
12static LIST_HEAD(tomoyo_io_buffer_list);
13/* Lock for protecting tomoyo_io_buffer_list. */
14static DEFINE_SPINLOCK(tomoyo_io_buffer_list_lock);
15
16/* Size of an element. */
17static const u8 tomoyo_element_size[TOMOYO_MAX_POLICY] = {
18 [TOMOYO_ID_GROUP] = sizeof(struct tomoyo_group),
19 [TOMOYO_ID_PATH_GROUP] = sizeof(struct tomoyo_path_group),
20 [TOMOYO_ID_NUMBER_GROUP] = sizeof(struct tomoyo_number_group),
21 [TOMOYO_ID_AGGREGATOR] = sizeof(struct tomoyo_aggregator),
22 [TOMOYO_ID_TRANSITION_CONTROL] =
23 sizeof(struct tomoyo_transition_control),
24 [TOMOYO_ID_MANAGER] = sizeof(struct tomoyo_manager),
25 /* [TOMOYO_ID_CONDITION] = "struct tomoyo_condition"->size, */
26 /* [TOMOYO_ID_NAME] = "struct tomoyo_name"->size, */
27 /* [TOMOYO_ID_ACL] =
28 tomoyo_acl_size["struct tomoyo_acl_info"->type], */
29 [TOMOYO_ID_DOMAIN] = sizeof(struct tomoyo_domain_info),
30};
31
32/* Size of a domain ACL element. */
33static const u8 tomoyo_acl_size[] = {
34 [TOMOYO_TYPE_PATH_ACL] = sizeof(struct tomoyo_path_acl),
35 [TOMOYO_TYPE_PATH2_ACL] = sizeof(struct tomoyo_path2_acl),
36 [TOMOYO_TYPE_PATH_NUMBER_ACL] = sizeof(struct tomoyo_path_number_acl),
37 [TOMOYO_TYPE_MKDEV_ACL] = sizeof(struct tomoyo_mkdev_acl),
38 [TOMOYO_TYPE_MOUNT_ACL] = sizeof(struct tomoyo_mount_acl),
39};
40
41/**
42 * tomoyo_struct_used_by_io_buffer - Check whether the list element is used by /sys/kernel/security/tomoyo/ users or not.
43 *
44 * @element: Pointer to "struct list_head".
45 *
46 * Returns true if @element is used by /sys/kernel/security/tomoyo/ users,
47 * false otherwise.
48 */
49static bool tomoyo_struct_used_by_io_buffer(const struct list_head *element)
50{
51 struct tomoyo_io_buffer *head;
52 bool in_use = false;
53
54 spin_lock(&tomoyo_io_buffer_list_lock);
55 list_for_each_entry(head, &tomoyo_io_buffer_list, list) {
56 head->users++;
57 spin_unlock(&tomoyo_io_buffer_list_lock);
58 if (mutex_lock_interruptible(&head->io_sem)) {
59 in_use = true;
60 goto out;
61 }
62 if (head->r.domain == element || head->r.group == element ||
63 head->r.acl == element || &head->w.domain->list == element)
64 in_use = true;
65 mutex_unlock(&head->io_sem);
66out:
67 spin_lock(&tomoyo_io_buffer_list_lock);
68 head->users--;
69 if (in_use)
70 break;
71 }
72 spin_unlock(&tomoyo_io_buffer_list_lock);
73 return in_use;
74}
75
76/**
77 * tomoyo_name_used_by_io_buffer - Check whether the string is used by /sys/kernel/security/tomoyo/ users or not.
78 *
79 * @string: String to check.
80 * @size: Memory allocated for @string .
81 *
82 * Returns true if @string is used by /sys/kernel/security/tomoyo/ users,
83 * false otherwise.
84 */
85static bool tomoyo_name_used_by_io_buffer(const char *string,
86 const size_t size)
87{
88 struct tomoyo_io_buffer *head;
89 bool in_use = false;
90
91 spin_lock(&tomoyo_io_buffer_list_lock);
92 list_for_each_entry(head, &tomoyo_io_buffer_list, list) {
93 int i;
94 head->users++;
95 spin_unlock(&tomoyo_io_buffer_list_lock);
96 if (mutex_lock_interruptible(&head->io_sem)) {
97 in_use = true;
98 goto out;
99 }
100 for (i = 0; i < TOMOYO_MAX_IO_READ_QUEUE; i++) {
101 const char *w = head->r.w[i];
102 if (w < string || w > string + size)
103 continue;
104 in_use = true;
105 break;
106 }
107 mutex_unlock(&head->io_sem);
108out:
109 spin_lock(&tomoyo_io_buffer_list_lock);
110 head->users--;
111 if (in_use)
112 break;
113 }
114 spin_unlock(&tomoyo_io_buffer_list_lock);
115 return in_use;
116}
117
118/* Structure for garbage collection. */
119struct tomoyo_gc {
120 struct list_head list;
121 enum tomoyo_policy_id type;
122 size_t size;
123 struct list_head *element;
124};
125/* List of entries to be deleted. */
126static LIST_HEAD(tomoyo_gc_list);
127/* Length of tomoyo_gc_list. */
128static int tomoyo_gc_list_len;
129
130/**
131 * tomoyo_add_to_gc - Add an entry to to be deleted list.
132 *
133 * @type: One of values in "enum tomoyo_policy_id".
134 * @element: Pointer to "struct list_head".
135 *
136 * Returns true on success, false otherwise.
137 *
138 * Caller holds tomoyo_policy_lock mutex.
139 *
140 * Adding an entry needs kmalloc(). Thus, if we try to add thousands of
141 * entries at once, it will take too long time. Thus, do not add more than 128
142 * entries per a scan. But to be able to handle worst case where all entries
143 * are in-use, we accept one more entry per a scan.
144 *
145 * If we use singly linked list using "struct list_head"->prev (which is
146 * LIST_POISON2), we can avoid kmalloc().
147 */
148static bool tomoyo_add_to_gc(const int type, struct list_head *element)
149{
150 struct tomoyo_gc *entry = kzalloc(sizeof(*entry), GFP_ATOMIC);
151 if (!entry)
152 return false;
153 entry->type = type;
154 if (type == TOMOYO_ID_ACL)
155 entry->size = tomoyo_acl_size[
156 container_of(element,
157 typeof(struct tomoyo_acl_info),
158 list)->type];
159 else if (type == TOMOYO_ID_NAME)
160 entry->size = strlen(container_of(element,
161 typeof(struct tomoyo_name),
162 head.list)->entry.name) + 1;
163 else if (type == TOMOYO_ID_CONDITION)
164 entry->size =
165 container_of(element, typeof(struct tomoyo_condition),
166 head.list)->size;
167 else
168 entry->size = tomoyo_element_size[type];
169 entry->element = element;
170 list_add(&entry->list, &tomoyo_gc_list);
171 list_del_rcu(element);
172 return tomoyo_gc_list_len++ < 128;
173}
174
175/**
176 * tomoyo_element_linked_by_gc - Validate next element of an entry.
177 *
178 * @element: Pointer to an element.
179 * @size: Size of @element in byte.
180 *
181 * Returns true if @element is linked by other elements in the garbage
182 * collector's queue, false otherwise.
183 */
184static bool tomoyo_element_linked_by_gc(const u8 *element, const size_t size)
185{
186 struct tomoyo_gc *p;
187 list_for_each_entry(p, &tomoyo_gc_list, list) {
188 const u8 *ptr = (const u8 *) p->element->next;
189 if (ptr < element || element + size < ptr)
190 continue;
191 return true;
192 }
193 return false;
194}
195
196/**
197 * tomoyo_del_transition_control - Delete members in "struct tomoyo_transition_control".
198 *
199 * @element: Pointer to "struct list_head".
200 *
201 * Returns nothing.
202 */
203static void tomoyo_del_transition_control(struct list_head *element)
204{
205 struct tomoyo_transition_control *ptr =
206 container_of(element, typeof(*ptr), head.list);
207 tomoyo_put_name(ptr->domainname);
208 tomoyo_put_name(ptr->program);
209}
210
211/**
212 * tomoyo_del_aggregator - Delete members in "struct tomoyo_aggregator".
213 *
214 * @element: Pointer to "struct list_head".
215 *
216 * Returns nothing.
217 */
218static void tomoyo_del_aggregator(struct list_head *element)
219{
220 struct tomoyo_aggregator *ptr =
221 container_of(element, typeof(*ptr), head.list);
222 tomoyo_put_name(ptr->original_name);
223 tomoyo_put_name(ptr->aggregated_name);
224}
225
226/**
227 * tomoyo_del_manager - Delete members in "struct tomoyo_manager".
228 *
229 * @element: Pointer to "struct list_head".
230 *
231 * Returns nothing.
232 */
233static void tomoyo_del_manager(struct list_head *element)
234{
235 struct tomoyo_manager *ptr =
236 container_of(element, typeof(*ptr), head.list);
237 tomoyo_put_name(ptr->manager);
238}
239
240/**
241 * tomoyo_del_acl - Delete members in "struct tomoyo_acl_info".
242 *
243 * @element: Pointer to "struct list_head".
244 *
245 * Returns nothing.
246 */
247static void tomoyo_del_acl(struct list_head *element)
248{
249 struct tomoyo_acl_info *acl =
250 container_of(element, typeof(*acl), list);
251 tomoyo_put_condition(acl->cond);
252 switch (acl->type) {
253 case TOMOYO_TYPE_PATH_ACL:
254 {
255 struct tomoyo_path_acl *entry
256 = container_of(acl, typeof(*entry), head);
257 tomoyo_put_name_union(&entry->name);
258 }
259 break;
260 case TOMOYO_TYPE_PATH2_ACL:
261 {
262 struct tomoyo_path2_acl *entry
263 = container_of(acl, typeof(*entry), head);
264 tomoyo_put_name_union(&entry->name1);
265 tomoyo_put_name_union(&entry->name2);
266 }
267 break;
268 case TOMOYO_TYPE_PATH_NUMBER_ACL:
269 {
270 struct tomoyo_path_number_acl *entry
271 = container_of(acl, typeof(*entry), head);
272 tomoyo_put_name_union(&entry->name);
273 tomoyo_put_number_union(&entry->number);
274 }
275 break;
276 case TOMOYO_TYPE_MKDEV_ACL:
277 {
278 struct tomoyo_mkdev_acl *entry
279 = container_of(acl, typeof(*entry), head);
280 tomoyo_put_name_union(&entry->name);
281 tomoyo_put_number_union(&entry->mode);
282 tomoyo_put_number_union(&entry->major);
283 tomoyo_put_number_union(&entry->minor);
284 }
285 break;
286 case TOMOYO_TYPE_MOUNT_ACL:
287 {
288 struct tomoyo_mount_acl *entry
289 = container_of(acl, typeof(*entry), head);
290 tomoyo_put_name_union(&entry->dev_name);
291 tomoyo_put_name_union(&entry->dir_name);
292 tomoyo_put_name_union(&entry->fs_type);
293 tomoyo_put_number_union(&entry->flags);
294 }
295 break;
296 }
297}
298
299/**
300 * tomoyo_del_domain - Delete members in "struct tomoyo_domain_info".
301 *
302 * @element: Pointer to "struct list_head".
303 *
304 * Returns true if deleted, false otherwise.
305 */
306static bool tomoyo_del_domain(struct list_head *element)
307{
308 struct tomoyo_domain_info *domain =
309 container_of(element, typeof(*domain), list);
310 struct tomoyo_acl_info *acl;
311 struct tomoyo_acl_info *tmp;
312 /*
313 * Since we don't protect whole execve() operation using SRCU,
314 * we need to recheck domain->users at this point.
315 *
316 * (1) Reader starts SRCU section upon execve().
317 * (2) Reader traverses tomoyo_domain_list and finds this domain.
318 * (3) Writer marks this domain as deleted.
319 * (4) Garbage collector removes this domain from tomoyo_domain_list
320 * because this domain is marked as deleted and used by nobody.
321 * (5) Reader saves reference to this domain into
322 * "struct linux_binprm"->cred->security .
323 * (6) Reader finishes SRCU section, although execve() operation has
324 * not finished yet.
325 * (7) Garbage collector waits for SRCU synchronization.
326 * (8) Garbage collector kfree() this domain because this domain is
327 * used by nobody.
328 * (9) Reader finishes execve() operation and restores this domain from
329 * "struct linux_binprm"->cred->security.
330 *
331 * By updating domain->users at (5), we can solve this race problem
332 * by rechecking domain->users at (8).
333 */
334 if (atomic_read(&domain->users))
335 return false;
336 list_for_each_entry_safe(acl, tmp, &domain->acl_info_list, list) {
337 tomoyo_del_acl(&acl->list);
338 tomoyo_memory_free(acl);
339 }
340 tomoyo_put_name(domain->domainname);
341 return true;
342}
343
344/**
345 * tomoyo_del_condition - Delete members in "struct tomoyo_condition".
346 *
347 * @element: Pointer to "struct list_head".
348 *
349 * Returns nothing.
350 */
351void tomoyo_del_condition(struct list_head *element)
352{
353 struct tomoyo_condition *cond = container_of(element, typeof(*cond),
354 head.list);
355 const u16 condc = cond->condc;
356 const u16 numbers_count = cond->numbers_count;
357 const u16 names_count = cond->names_count;
358 const u16 argc = cond->argc;
359 const u16 envc = cond->envc;
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 struct tomoyo_name_union *names_p
366 = (struct tomoyo_name_union *) (numbers_p + numbers_count);
367 const struct tomoyo_argv *argv
368 = (const struct tomoyo_argv *) (names_p + names_count);
369 const struct tomoyo_envp *envp
370 = (const struct tomoyo_envp *) (argv + argc);
371 for (i = 0; i < numbers_count; i++)
372 tomoyo_put_number_union(numbers_p++);
373 for (i = 0; i < names_count; i++)
374 tomoyo_put_name_union(names_p++);
375 for (i = 0; i < argc; argv++, i++)
376 tomoyo_put_name(argv->value);
377 for (i = 0; i < envc; envp++, i++) {
378 tomoyo_put_name(envp->name);
379 tomoyo_put_name(envp->value);
380 }
381}
382
383/**
384 * tomoyo_del_name - Delete members in "struct tomoyo_name".
385 *
386 * @element: Pointer to "struct list_head".
387 *
388 * Returns nothing.
389 */
390static void tomoyo_del_name(struct list_head *element)
391{
392 const struct tomoyo_name *ptr =
393 container_of(element, typeof(*ptr), head.list);
394}
395
396/**
397 * tomoyo_del_path_group - Delete members in "struct tomoyo_path_group".
398 *
399 * @element: Pointer to "struct list_head".
400 *
401 * Returns nothing.
402 */
403static void tomoyo_del_path_group(struct list_head *element)
404{
405 struct tomoyo_path_group *member =
406 container_of(element, typeof(*member), head.list);
407 tomoyo_put_name(member->member_name);
408}
409
410/**
411 * tomoyo_del_group - Delete "struct tomoyo_group".
412 *
413 * @element: Pointer to "struct list_head".
414 *
415 * Returns nothing.
416 */
417static void tomoyo_del_group(struct list_head *element)
418{
419 struct tomoyo_group *group =
420 container_of(element, typeof(*group), head.list);
421 tomoyo_put_name(group->group_name);
422}
423
424/**
425 * tomoyo_del_number_group - Delete members in "struct tomoyo_number_group".
426 *
427 * @element: Pointer to "struct list_head".
428 *
429 * Returns nothing.
430 */
431static void tomoyo_del_number_group(struct list_head *element)
432{
433 struct tomoyo_number_group *member =
434 container_of(element, typeof(*member), head.list);
435}
436
437/**
438 * tomoyo_collect_member - Delete elements with "struct tomoyo_acl_head".
439 *
440 * @id: One of values in "enum tomoyo_policy_id".
441 * @member_list: Pointer to "struct list_head".
442 *
443 * Returns true if some elements are deleted, false otherwise.
444 */
445static bool tomoyo_collect_member(const enum tomoyo_policy_id id,
446 struct list_head *member_list)
447{
448 struct tomoyo_acl_head *member;
449 list_for_each_entry(member, member_list, list) {
450 if (!member->is_deleted)
451 continue;
452 if (!tomoyo_add_to_gc(id, &member->list))
453 return false;
454 }
455 return true;
456}
457
458/**
459 * tomoyo_collect_acl - Delete elements in "struct tomoyo_domain_info".
460 *
461 * @list: Pointer to "struct list_head".
462 *
463 * Returns true if some elements are deleted, false otherwise.
464 */
465static bool tomoyo_collect_acl(struct list_head *list)
466{
467 struct tomoyo_acl_info *acl;
468 list_for_each_entry(acl, list, list) {
469 if (!acl->is_deleted)
470 continue;
471 if (!tomoyo_add_to_gc(TOMOYO_ID_ACL, &acl->list))
472 return false;
473 }
474 return true;
475}
476
477/**
478 * tomoyo_collect_entry - Scan lists for deleted elements.
479 *
480 * Returns nothing.
481 */
482static void tomoyo_collect_entry(void)
483{
484 int i;
485 enum tomoyo_policy_id id;
486 struct tomoyo_policy_namespace *ns;
487 int idx;
488 if (mutex_lock_interruptible(&tomoyo_policy_lock))
489 return;
490 idx = tomoyo_read_lock();
491 {
492 struct tomoyo_domain_info *domain;
493 list_for_each_entry_rcu(domain, &tomoyo_domain_list, list) {
494 if (!tomoyo_collect_acl(&domain->acl_info_list))
495 goto unlock;
496 if (!domain->is_deleted || atomic_read(&domain->users))
497 continue;
498 /*
499 * Nobody is referring this domain. But somebody may
500 * refer this domain after successful execve().
501 * We recheck domain->users after SRCU synchronization.
502 */
503 if (!tomoyo_add_to_gc(TOMOYO_ID_DOMAIN, &domain->list))
504 goto unlock;
505 }
506 }
507 list_for_each_entry_rcu(ns, &tomoyo_namespace_list, namespace_list) {
508 for (id = 0; id < TOMOYO_MAX_POLICY; id++)
509 if (!tomoyo_collect_member(id, &ns->policy_list[id]))
510 goto unlock;
511 for (i = 0; i < TOMOYO_MAX_ACL_GROUPS; i++)
512 if (!tomoyo_collect_acl(&ns->acl_group[i]))
513 goto unlock;
514 for (i = 0; i < TOMOYO_MAX_GROUP; i++) {
515 struct list_head *list = &ns->group_list[i];
516 struct tomoyo_group *group;
517 switch (i) {
518 case 0:
519 id = TOMOYO_ID_PATH_GROUP;
520 break;
521 default:
522 id = TOMOYO_ID_NUMBER_GROUP;
523 break;
524 }
525 list_for_each_entry(group, list, head.list) {
526 if (!tomoyo_collect_member
527 (id, &group->member_list))
528 goto unlock;
529 if (!list_empty(&group->member_list) ||
530 atomic_read(&group->head.users))
531 continue;
532 if (!tomoyo_add_to_gc(TOMOYO_ID_GROUP,
533 &group->head.list))
534 goto unlock;
535 }
536 }
537 }
538 id = TOMOYO_ID_CONDITION;
539 for (i = 0; i < TOMOYO_MAX_HASH + 1; i++) {
540 struct list_head *list = !i ?
541 &tomoyo_condition_list : &tomoyo_name_list[i - 1];
542 struct tomoyo_shared_acl_head *ptr;
543 list_for_each_entry(ptr, list, list) {
544 if (atomic_read(&ptr->users))
545 continue;
546 if (!tomoyo_add_to_gc(id, &ptr->list))
547 goto unlock;
548 }
549 id = TOMOYO_ID_NAME;
550 }
551unlock:
552 tomoyo_read_unlock(idx);
553 mutex_unlock(&tomoyo_policy_lock);
554}
555
556/**
557 * tomoyo_kfree_entry - Delete entries in tomoyo_gc_list.
558 *
559 * Returns true if some entries were kfree()d, false otherwise.
560 */
561static bool tomoyo_kfree_entry(void)
562{
563 struct tomoyo_gc *p;
564 struct tomoyo_gc *tmp;
565 bool result = false;
566
567 list_for_each_entry_safe(p, tmp, &tomoyo_gc_list, list) {
568 struct list_head *element = p->element;
569
570 /*
571 * list_del_rcu() in tomoyo_add_to_gc() guarantees that the
572 * list element became no longer reachable from the list which
573 * the element was originally on (e.g. tomoyo_domain_list).
574 * Also, synchronize_srcu() in tomoyo_gc_thread() guarantees
575 * that the list element became no longer referenced by syscall
576 * users.
577 *
578 * However, there are three users which may still be using the
579 * list element. We need to defer until all of these users
580 * forget the list element.
581 *
582 * Firstly, defer until "struct tomoyo_io_buffer"->r.{domain,
583 * group,acl} and "struct tomoyo_io_buffer"->w.domain forget
584 * the list element.
585 */
586 if (tomoyo_struct_used_by_io_buffer(element))
587 continue;
588 /*
589 * Secondly, defer until all other elements in the
590 * tomoyo_gc_list list forget the list element.
591 */
592 if (tomoyo_element_linked_by_gc((const u8 *) element, p->size))
593 continue;
594 switch (p->type) {
595 case TOMOYO_ID_TRANSITION_CONTROL:
596 tomoyo_del_transition_control(element);
597 break;
598 case TOMOYO_ID_AGGREGATOR:
599 tomoyo_del_aggregator(element);
600 break;
601 case TOMOYO_ID_MANAGER:
602 tomoyo_del_manager(element);
603 break;
604 case TOMOYO_ID_CONDITION:
605 tomoyo_del_condition(element);
606 break;
607 case TOMOYO_ID_NAME:
608 /*
609 * Thirdly, defer until all "struct tomoyo_io_buffer"
610 * ->r.w[] forget the list element.
611 */
612 if (tomoyo_name_used_by_io_buffer(
613 container_of(element, typeof(struct tomoyo_name),
614 head.list)->entry.name, p->size))
615 continue;
616 tomoyo_del_name(element);
617 break;
618 case TOMOYO_ID_ACL:
619 tomoyo_del_acl(element);
620 break;
621 case TOMOYO_ID_DOMAIN:
622 if (!tomoyo_del_domain(element))
623 continue;
624 break;
625 case TOMOYO_ID_PATH_GROUP:
626 tomoyo_del_path_group(element);
627 break;
628 case TOMOYO_ID_GROUP:
629 tomoyo_del_group(element);
630 break;
631 case TOMOYO_ID_NUMBER_GROUP:
632 tomoyo_del_number_group(element);
633 break;
634 case TOMOYO_MAX_POLICY:
635 break;
636 }
637 tomoyo_memory_free(element);
638 list_del(&p->list);
639 kfree(p);
640 tomoyo_gc_list_len--;
641 result = true;
642 }
643 return result;
644}
645
646/**
647 * tomoyo_gc_thread - Garbage collector thread function.
648 *
649 * @unused: Unused.
650 *
651 * In case OOM-killer choose this thread for termination, we create this thread
652 * as a short live thread whenever /sys/kernel/security/tomoyo/ interface was
653 * close()d.
654 *
655 * Returns 0.
656 */
657static int tomoyo_gc_thread(void *unused)
658{
659 /* Garbage collector thread is exclusive. */
660 static DEFINE_MUTEX(tomoyo_gc_mutex);
661 if (!mutex_trylock(&tomoyo_gc_mutex))
662 goto out;
663 daemonize("GC for TOMOYO");
664 do {
665 tomoyo_collect_entry();
666 if (list_empty(&tomoyo_gc_list))
667 break;
668 synchronize_srcu(&tomoyo_ss);
669 } while (tomoyo_kfree_entry());
670 {
671 struct tomoyo_io_buffer *head;
672 struct tomoyo_io_buffer *tmp;
673
674 spin_lock(&tomoyo_io_buffer_list_lock);
675 list_for_each_entry_safe(head, tmp, &tomoyo_io_buffer_list,
676 list) {
677 if (head->users)
678 continue;
679 list_del(&head->list);
680 kfree(head->read_buf);
681 kfree(head->write_buf);
682 kfree(head);
683 }
684 spin_unlock(&tomoyo_io_buffer_list_lock);
685 }
686 mutex_unlock(&tomoyo_gc_mutex);
687out:
688 /* This acts as do_exit(0). */
689 return 0;
690}
691
692/**
693 * tomoyo_notify_gc - Register/unregister /sys/kernel/security/tomoyo/ users.
694 *
695 * @head: Pointer to "struct tomoyo_io_buffer".
696 * @is_register: True if register, false if unregister.
697 *
698 * Returns nothing.
699 */
700void tomoyo_notify_gc(struct tomoyo_io_buffer *head, const bool is_register)
701{
702 bool is_write = false;
703
704 spin_lock(&tomoyo_io_buffer_list_lock);
705 if (is_register) {
706 head->users = 1;
707 list_add(&head->list, &tomoyo_io_buffer_list);
708 } else {
709 is_write = head->write_buf != NULL;
710 if (!--head->users) {
711 list_del(&head->list);
712 kfree(head->read_buf);
713 kfree(head->write_buf);
714 kfree(head);
715 }
716 }
717 spin_unlock(&tomoyo_io_buffer_list_lock);
718 if (is_write) {
719 struct task_struct *task = kthread_create(tomoyo_gc_thread,
720 NULL,
721 "GC for TOMOYO");
722 if (!IS_ERR(task))
723 wake_up_process(task);
724 }
725}