OMAPDSS: VENC: fix NULL pointer dereference in DSS2 VENC sysfs debug attr on OMAP4
[zen-stable.git] / security / tomoyo / gc.c
blob986a6a75686843f4a6afeed9b6492650db79d055
1 /*
2 * security/tomoyo/gc.c
4 * Copyright (C) 2005-2011 NTT DATA CORPORATION
5 */
7 #include "common.h"
8 #include <linux/kthread.h>
9 #include <linux/slab.h>
11 /**
12 * tomoyo_memory_free - Free memory for elements.
14 * @ptr: Pointer to allocated memory.
16 * Returns nothing.
18 * Caller holds tomoyo_policy_lock mutex.
20 static inline void tomoyo_memory_free(void *ptr)
22 tomoyo_memory_used[TOMOYO_MEMORY_POLICY] -= ksize(ptr);
23 kfree(ptr);
26 /* The list for "struct tomoyo_io_buffer". */
27 static LIST_HEAD(tomoyo_io_buffer_list);
28 /* Lock for protecting tomoyo_io_buffer_list. */
29 static DEFINE_SPINLOCK(tomoyo_io_buffer_list_lock);
31 /**
32 * tomoyo_struct_used_by_io_buffer - Check whether the list element is used by /sys/kernel/security/tomoyo/ users or not.
34 * @element: Pointer to "struct list_head".
36 * Returns true if @element is used by /sys/kernel/security/tomoyo/ users,
37 * false otherwise.
39 static bool tomoyo_struct_used_by_io_buffer(const struct list_head *element)
41 struct tomoyo_io_buffer *head;
42 bool in_use = false;
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;
58 spin_unlock(&tomoyo_io_buffer_list_lock);
59 return in_use;
62 /**
63 * tomoyo_name_used_by_io_buffer - Check whether the string is used by /sys/kernel/security/tomoyo/ users or not.
65 * @string: String to check.
67 * Returns true if @string is used by /sys/kernel/security/tomoyo/ users,
68 * false otherwise.
70 static bool tomoyo_name_used_by_io_buffer(const char *string)
72 struct tomoyo_io_buffer *head;
73 const size_t size = strlen(string) + 1;
74 bool in_use = false;
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;
89 mutex_unlock(&head->io_sem);
90 spin_lock(&tomoyo_io_buffer_list_lock);
91 head->users--;
92 if (in_use)
93 break;
95 spin_unlock(&tomoyo_io_buffer_list_lock);
96 return in_use;
99 /**
100 * tomoyo_del_transition_control - Delete members in "struct tomoyo_transition_control".
102 * @element: Pointer to "struct list_head".
104 * Returns nothing.
106 static inline void tomoyo_del_transition_control(struct list_head *element)
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);
115 * tomoyo_del_aggregator - Delete members in "struct tomoyo_aggregator".
117 * @element: Pointer to "struct list_head".
119 * Returns nothing.
121 static inline void tomoyo_del_aggregator(struct list_head *element)
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);
130 * tomoyo_del_manager - Delete members in "struct tomoyo_manager".
132 * @element: Pointer to "struct list_head".
134 * Returns nothing.
136 static inline void tomoyo_del_manager(struct list_head *element)
138 struct tomoyo_manager *ptr =
139 container_of(element, typeof(*ptr), head.list);
140 tomoyo_put_name(ptr->manager);
144 * tomoyo_del_acl - Delete members in "struct tomoyo_acl_info".
146 * @element: Pointer to "struct list_head".
148 * Returns nothing.
150 static void tomoyo_del_acl(struct list_head *element)
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:
158 struct tomoyo_path_acl *entry
159 = container_of(acl, typeof(*entry), head);
160 tomoyo_put_name_union(&entry->name);
162 break;
163 case TOMOYO_TYPE_PATH2_ACL:
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);
170 break;
171 case TOMOYO_TYPE_PATH_NUMBER_ACL:
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);
178 break;
179 case TOMOYO_TYPE_MKDEV_ACL:
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);
188 break;
189 case TOMOYO_TYPE_MOUNT_ACL:
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);
198 break;
199 case TOMOYO_TYPE_ENV_ACL:
201 struct tomoyo_env_acl *entry =
202 container_of(acl, typeof(*entry), head);
204 tomoyo_put_name(entry->env);
206 break;
207 case TOMOYO_TYPE_INET_ACL:
209 struct tomoyo_inet_acl *entry =
210 container_of(acl, typeof(*entry), head);
212 tomoyo_put_group(entry->address.group);
213 tomoyo_put_number_union(&entry->port);
215 break;
216 case TOMOYO_TYPE_UNIX_ACL:
218 struct tomoyo_unix_acl *entry =
219 container_of(acl, typeof(*entry), head);
221 tomoyo_put_name_union(&entry->name);
223 break;
224 case TOMOYO_TYPE_MANUAL_TASK_ACL:
226 struct tomoyo_task_acl *entry =
227 container_of(acl, typeof(*entry), head);
228 tomoyo_put_name(entry->domainname);
230 break;
235 * tomoyo_del_domain - Delete members in "struct tomoyo_domain_info".
237 * @element: Pointer to "struct list_head".
239 * Returns nothing.
241 * Caller holds tomoyo_policy_lock mutex.
243 static inline void tomoyo_del_domain(struct list_head *element)
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;
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.
254 list_for_each_entry_safe(acl, tmp, &domain->acl_info_list, list) {
255 tomoyo_del_acl(&acl->list);
256 tomoyo_memory_free(acl);
258 tomoyo_put_name(domain->domainname);
262 * tomoyo_del_condition - Delete members in "struct tomoyo_condition".
264 * @element: Pointer to "struct list_head".
266 * Returns nothing.
268 void tomoyo_del_condition(struct list_head *element)
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);
301 * tomoyo_del_name - Delete members in "struct tomoyo_name".
303 * @element: Pointer to "struct list_head".
305 * Returns nothing.
307 static inline void tomoyo_del_name(struct list_head *element)
309 /* Nothing to do. */
313 * tomoyo_del_path_group - Delete members in "struct tomoyo_path_group".
315 * @element: Pointer to "struct list_head".
317 * Returns nothing.
319 static inline void tomoyo_del_path_group(struct list_head *element)
321 struct tomoyo_path_group *member =
322 container_of(element, typeof(*member), head.list);
323 tomoyo_put_name(member->member_name);
327 * tomoyo_del_group - Delete "struct tomoyo_group".
329 * @element: Pointer to "struct list_head".
331 * Returns nothing.
333 static inline void tomoyo_del_group(struct list_head *element)
335 struct tomoyo_group *group =
336 container_of(element, typeof(*group), head.list);
337 tomoyo_put_name(group->group_name);
341 * tomoyo_del_address_group - Delete members in "struct tomoyo_address_group".
343 * @element: Pointer to "struct list_head".
345 * Returns nothing.
347 static inline void tomoyo_del_address_group(struct list_head *element)
349 /* Nothing to do. */
353 * tomoyo_del_number_group - Delete members in "struct tomoyo_number_group".
355 * @element: Pointer to "struct list_head".
357 * Returns nothing.
359 static inline void tomoyo_del_number_group(struct list_head *element)
361 /* Nothing to do. */
365 * tomoyo_try_to_gc - Try to kfree() an entry.
367 * @type: One of values in "enum tomoyo_policy_id".
368 * @element: Pointer to "struct list_head".
370 * Returns nothing.
372 * Caller holds tomoyo_policy_lock mutex.
374 static void tomoyo_try_to_gc(const enum tomoyo_policy_id type,
375 struct list_head *element)
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.
383 __list_del_entry(element);
384 mutex_unlock(&tomoyo_policy_lock);
385 synchronize_srcu(&tomoyo_ss);
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.
390 * Don't kfree() until "struct tomoyo_io_buffer"->r.{domain,group,acl}
391 * and "struct tomoyo_io_buffer"->w.domain forget this element.
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:
422 * Don't kfree() until all "struct tomoyo_io_buffer"->r.w[]
423 * forget this element.
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:
436 * Don't kfree() until all "struct cred"->security forget this
437 * element.
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;
447 mutex_lock(&tomoyo_policy_lock);
448 if (type == TOMOYO_ID_DOMAIN)
449 tomoyo_del_domain(element);
450 tomoyo_memory_free(element);
451 return;
452 reinject:
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.
461 mutex_lock(&tomoyo_policy_lock);
462 list_add_rcu(element, element->prev);
466 * tomoyo_collect_member - Delete elements with "struct tomoyo_acl_head".
468 * @id: One of values in "enum tomoyo_policy_id".
469 * @member_list: Pointer to "struct list_head".
471 * Returns nothing.
473 static void tomoyo_collect_member(const enum tomoyo_policy_id id,
474 struct list_head *member_list)
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);
487 * tomoyo_collect_acl - Delete elements in "struct tomoyo_domain_info".
489 * @list: Pointer to "struct list_head".
491 * Returns nothing.
493 static void tomoyo_collect_acl(struct list_head *list)
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);
506 * tomoyo_collect_entry - Try to kfree() deleted elements.
508 * Returns nothing.
510 static void tomoyo_collect_entry(void)
512 int i;
513 enum tomoyo_policy_id id;
514 struct tomoyo_policy_namespace *ns;
515 mutex_lock(&tomoyo_policy_lock);
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);
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]);
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);
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;
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);
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);
583 mutex_unlock(&tomoyo_policy_lock);
587 * tomoyo_gc_thread - Garbage collector thread function.
589 * @unused: Unused.
591 * Returns 0.
593 static int tomoyo_gc_thread(void *unused)
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();
601 struct tomoyo_io_buffer *head;
602 struct tomoyo_io_buffer *tmp;
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);
614 spin_unlock(&tomoyo_io_buffer_list_lock);
616 mutex_unlock(&tomoyo_gc_mutex);
617 out:
618 /* This acts as do_exit(0). */
619 return 0;
623 * tomoyo_notify_gc - Register/unregister /sys/kernel/security/tomoyo/ users.
625 * @head: Pointer to "struct tomoyo_io_buffer".
626 * @is_register: True if register, false if unregister.
628 * Returns nothing.
630 void tomoyo_notify_gc(struct tomoyo_io_buffer *head, const bool is_register)
632 bool is_write = false;
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);
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);