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