4 * Copyright (C) 2005-2011 NTT DATA CORPORATION
8 #include <linux/kthread.h>
9 #include <linux/slab.h>
11 /* The list for "struct tomoyo_io_buffer". */
12 static LIST_HEAD(tomoyo_io_buffer_list
);
13 /* Lock for protecting tomoyo_io_buffer_list. */
14 static DEFINE_SPINLOCK(tomoyo_io_buffer_list_lock
);
16 /* Size of an element. */
17 static 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, */
28 tomoyo_acl_size["struct tomoyo_acl_info"->type], */
29 [TOMOYO_ID_DOMAIN
] = sizeof(struct tomoyo_domain_info
),
32 /* Size of a domain ACL element. */
33 static 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
),
42 * tomoyo_struct_used_by_io_buffer - Check whether the list element is used by /sys/kernel/security/tomoyo/ users or not.
44 * @element: Pointer to "struct list_head".
46 * Returns true if @element is used by /sys/kernel/security/tomoyo/ users,
49 static bool tomoyo_struct_used_by_io_buffer(const struct list_head
*element
)
51 struct tomoyo_io_buffer
*head
;
54 spin_lock(&tomoyo_io_buffer_list_lock
);
55 list_for_each_entry(head
, &tomoyo_io_buffer_list
, list
) {
57 spin_unlock(&tomoyo_io_buffer_list_lock
);
58 if (mutex_lock_interruptible(&head
->io_sem
)) {
62 if (head
->r
.domain
== element
|| head
->r
.group
== element
||
63 head
->r
.acl
== element
|| &head
->w
.domain
->list
== element
)
65 mutex_unlock(&head
->io_sem
);
67 spin_lock(&tomoyo_io_buffer_list_lock
);
72 spin_unlock(&tomoyo_io_buffer_list_lock
);
77 * tomoyo_name_used_by_io_buffer - Check whether the string is used by /sys/kernel/security/tomoyo/ users or not.
79 * @string: String to check.
80 * @size: Memory allocated for @string .
82 * Returns true if @string is used by /sys/kernel/security/tomoyo/ users,
85 static bool tomoyo_name_used_by_io_buffer(const char *string
,
88 struct tomoyo_io_buffer
*head
;
91 spin_lock(&tomoyo_io_buffer_list_lock
);
92 list_for_each_entry(head
, &tomoyo_io_buffer_list
, list
) {
95 spin_unlock(&tomoyo_io_buffer_list_lock
);
96 if (mutex_lock_interruptible(&head
->io_sem
)) {
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
)
107 mutex_unlock(&head
->io_sem
);
109 spin_lock(&tomoyo_io_buffer_list_lock
);
114 spin_unlock(&tomoyo_io_buffer_list_lock
);
118 /* Structure for garbage collection. */
120 struct list_head list
;
121 enum tomoyo_policy_id type
;
123 struct list_head
*element
;
125 /* List of entries to be deleted. */
126 static LIST_HEAD(tomoyo_gc_list
);
127 /* Length of tomoyo_gc_list. */
128 static int tomoyo_gc_list_len
;
131 * tomoyo_add_to_gc - Add an entry to to be deleted list.
133 * @type: One of values in "enum tomoyo_policy_id".
134 * @element: Pointer to "struct list_head".
136 * Returns true on success, false otherwise.
138 * Caller holds tomoyo_policy_lock mutex.
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.
145 * If we use singly linked list using "struct list_head"->prev (which is
146 * LIST_POISON2), we can avoid kmalloc().
148 static bool tomoyo_add_to_gc(const int type
, struct list_head
*element
)
150 struct tomoyo_gc
*entry
= kzalloc(sizeof(*entry
), GFP_ATOMIC
);
154 if (type
== TOMOYO_ID_ACL
)
155 entry
->size
= tomoyo_acl_size
[
156 container_of(element
,
157 typeof(struct tomoyo_acl_info
),
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
)
165 container_of(element
, typeof(struct tomoyo_condition
),
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;
176 * tomoyo_element_linked_by_gc - Validate next element of an entry.
178 * @element: Pointer to an element.
179 * @size: Size of @element in byte.
181 * Returns true if @element is linked by other elements in the garbage
182 * collector's queue, false otherwise.
184 static bool tomoyo_element_linked_by_gc(const u8
*element
, const size_t size
)
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
)
197 * tomoyo_del_transition_control - Delete members in "struct tomoyo_transition_control".
199 * @element: Pointer to "struct list_head".
203 static void tomoyo_del_transition_control(struct list_head
*element
)
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
);
212 * tomoyo_del_aggregator - Delete members in "struct tomoyo_aggregator".
214 * @element: Pointer to "struct list_head".
218 static void tomoyo_del_aggregator(struct list_head
*element
)
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
);
227 * tomoyo_del_manager - Delete members in "struct tomoyo_manager".
229 * @element: Pointer to "struct list_head".
233 static void tomoyo_del_manager(struct list_head
*element
)
235 struct tomoyo_manager
*ptr
=
236 container_of(element
, typeof(*ptr
), head
.list
);
237 tomoyo_put_name(ptr
->manager
);
241 * tomoyo_del_acl - Delete members in "struct tomoyo_acl_info".
243 * @element: Pointer to "struct list_head".
247 static void tomoyo_del_acl(struct list_head
*element
)
249 struct tomoyo_acl_info
*acl
=
250 container_of(element
, typeof(*acl
), list
);
251 tomoyo_put_condition(acl
->cond
);
253 case TOMOYO_TYPE_PATH_ACL
:
255 struct tomoyo_path_acl
*entry
256 = container_of(acl
, typeof(*entry
), head
);
257 tomoyo_put_name_union(&entry
->name
);
260 case TOMOYO_TYPE_PATH2_ACL
:
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
);
268 case TOMOYO_TYPE_PATH_NUMBER_ACL
:
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
);
276 case TOMOYO_TYPE_MKDEV_ACL
:
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
);
286 case TOMOYO_TYPE_MOUNT_ACL
:
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
);
300 * tomoyo_del_domain - Delete members in "struct tomoyo_domain_info".
302 * @element: Pointer to "struct list_head".
304 * Returns true if deleted, false otherwise.
306 static bool tomoyo_del_domain(struct list_head
*element
)
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
;
313 * Since we don't protect whole execve() operation using SRCU,
314 * we need to recheck domain->users at this point.
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
325 * (7) Garbage collector waits for SRCU synchronization.
326 * (8) Garbage collector kfree() this domain because this domain is
328 * (9) Reader finishes execve() operation and restores this domain from
329 * "struct linux_binprm"->cred->security.
331 * By updating domain->users at (5), we can solve this race problem
332 * by rechecking domain->users at (8).
334 if (atomic_read(&domain
->users
))
336 list_for_each_entry_safe(acl
, tmp
, &domain
->acl_info_list
, list
) {
337 tomoyo_del_acl(&acl
->list
);
338 tomoyo_memory_free(acl
);
340 tomoyo_put_name(domain
->domainname
);
345 * tomoyo_del_condition - Delete members in "struct tomoyo_condition".
347 * @element: Pointer to "struct list_head".
351 void tomoyo_del_condition(struct list_head
*element
)
353 struct tomoyo_condition
*cond
= container_of(element
, typeof(*cond
),
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
;
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
);
384 * tomoyo_del_name - Delete members in "struct tomoyo_name".
386 * @element: Pointer to "struct list_head".
390 static void tomoyo_del_name(struct list_head
*element
)
392 const struct tomoyo_name
*ptr
=
393 container_of(element
, typeof(*ptr
), head
.list
);
397 * tomoyo_del_path_group - Delete members in "struct tomoyo_path_group".
399 * @element: Pointer to "struct list_head".
403 static void tomoyo_del_path_group(struct list_head
*element
)
405 struct tomoyo_path_group
*member
=
406 container_of(element
, typeof(*member
), head
.list
);
407 tomoyo_put_name(member
->member_name
);
411 * tomoyo_del_group - Delete "struct tomoyo_group".
413 * @element: Pointer to "struct list_head".
417 static void tomoyo_del_group(struct list_head
*element
)
419 struct tomoyo_group
*group
=
420 container_of(element
, typeof(*group
), head
.list
);
421 tomoyo_put_name(group
->group_name
);
425 * tomoyo_del_number_group - Delete members in "struct tomoyo_number_group".
427 * @element: Pointer to "struct list_head".
431 static void tomoyo_del_number_group(struct list_head
*element
)
433 struct tomoyo_number_group
*member
=
434 container_of(element
, typeof(*member
), head
.list
);
438 * tomoyo_collect_member - Delete elements with "struct tomoyo_acl_head".
440 * @id: One of values in "enum tomoyo_policy_id".
441 * @member_list: Pointer to "struct list_head".
443 * Returns true if some elements are deleted, false otherwise.
445 static bool tomoyo_collect_member(const enum tomoyo_policy_id id
,
446 struct list_head
*member_list
)
448 struct tomoyo_acl_head
*member
;
449 list_for_each_entry(member
, member_list
, list
) {
450 if (!member
->is_deleted
)
452 if (!tomoyo_add_to_gc(id
, &member
->list
))
459 * tomoyo_collect_acl - Delete elements in "struct tomoyo_domain_info".
461 * @list: Pointer to "struct list_head".
463 * Returns true if some elements are deleted, false otherwise.
465 static bool tomoyo_collect_acl(struct list_head
*list
)
467 struct tomoyo_acl_info
*acl
;
468 list_for_each_entry(acl
, list
, list
) {
469 if (!acl
->is_deleted
)
471 if (!tomoyo_add_to_gc(TOMOYO_ID_ACL
, &acl
->list
))
478 * tomoyo_collect_entry - Scan lists for deleted elements.
482 static void tomoyo_collect_entry(void)
485 enum tomoyo_policy_id id
;
486 struct tomoyo_policy_namespace
*ns
;
488 if (mutex_lock_interruptible(&tomoyo_policy_lock
))
490 idx
= tomoyo_read_lock();
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
))
496 if (!domain
->is_deleted
|| atomic_read(&domain
->users
))
499 * Nobody is referring this domain. But somebody may
500 * refer this domain after successful execve().
501 * We recheck domain->users after SRCU synchronization.
503 if (!tomoyo_add_to_gc(TOMOYO_ID_DOMAIN
, &domain
->list
))
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
]))
511 for (i
= 0; i
< TOMOYO_MAX_ACL_GROUPS
; i
++)
512 if (!tomoyo_collect_acl(&ns
->acl_group
[i
]))
514 for (i
= 0; i
< TOMOYO_MAX_GROUP
; i
++) {
515 struct list_head
*list
= &ns
->group_list
[i
];
516 struct tomoyo_group
*group
;
519 id
= TOMOYO_ID_PATH_GROUP
;
522 id
= TOMOYO_ID_NUMBER_GROUP
;
525 list_for_each_entry(group
, list
, head
.list
) {
526 if (!tomoyo_collect_member
527 (id
, &group
->member_list
))
529 if (!list_empty(&group
->member_list
) ||
530 atomic_read(&group
->head
.users
))
532 if (!tomoyo_add_to_gc(TOMOYO_ID_GROUP
,
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
))
546 if (!tomoyo_add_to_gc(id
, &ptr
->list
))
552 tomoyo_read_unlock(idx
);
553 mutex_unlock(&tomoyo_policy_lock
);
557 * tomoyo_kfree_entry - Delete entries in tomoyo_gc_list.
559 * Returns true if some entries were kfree()d, false otherwise.
561 static bool tomoyo_kfree_entry(void)
564 struct tomoyo_gc
*tmp
;
567 list_for_each_entry_safe(p
, tmp
, &tomoyo_gc_list
, list
) {
568 struct list_head
*element
= p
->element
;
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
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.
582 * Firstly, defer until "struct tomoyo_io_buffer"->r.{domain,
583 * group,acl} and "struct tomoyo_io_buffer"->w.domain forget
586 if (tomoyo_struct_used_by_io_buffer(element
))
589 * Secondly, defer until all other elements in the
590 * tomoyo_gc_list list forget the list element.
592 if (tomoyo_element_linked_by_gc((const u8
*) element
, p
->size
))
595 case TOMOYO_ID_TRANSITION_CONTROL
:
596 tomoyo_del_transition_control(element
);
598 case TOMOYO_ID_AGGREGATOR
:
599 tomoyo_del_aggregator(element
);
601 case TOMOYO_ID_MANAGER
:
602 tomoyo_del_manager(element
);
604 case TOMOYO_ID_CONDITION
:
605 tomoyo_del_condition(element
);
609 * Thirdly, defer until all "struct tomoyo_io_buffer"
610 * ->r.w[] forget the list element.
612 if (tomoyo_name_used_by_io_buffer(
613 container_of(element
, typeof(struct tomoyo_name
),
614 head
.list
)->entry
.name
, p
->size
))
616 tomoyo_del_name(element
);
619 tomoyo_del_acl(element
);
621 case TOMOYO_ID_DOMAIN
:
622 if (!tomoyo_del_domain(element
))
625 case TOMOYO_ID_PATH_GROUP
:
626 tomoyo_del_path_group(element
);
628 case TOMOYO_ID_GROUP
:
629 tomoyo_del_group(element
);
631 case TOMOYO_ID_NUMBER_GROUP
:
632 tomoyo_del_number_group(element
);
634 case TOMOYO_MAX_POLICY
:
637 tomoyo_memory_free(element
);
640 tomoyo_gc_list_len
--;
647 * tomoyo_gc_thread - Garbage collector thread function.
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
657 static int tomoyo_gc_thread(void *unused
)
659 /* Garbage collector thread is exclusive. */
660 static DEFINE_MUTEX(tomoyo_gc_mutex
);
661 if (!mutex_trylock(&tomoyo_gc_mutex
))
663 daemonize("GC for TOMOYO");
665 tomoyo_collect_entry();
666 if (list_empty(&tomoyo_gc_list
))
668 synchronize_srcu(&tomoyo_ss
);
669 } while (tomoyo_kfree_entry());
671 struct tomoyo_io_buffer
*head
;
672 struct tomoyo_io_buffer
*tmp
;
674 spin_lock(&tomoyo_io_buffer_list_lock
);
675 list_for_each_entry_safe(head
, tmp
, &tomoyo_io_buffer_list
,
679 list_del(&head
->list
);
680 kfree(head
->read_buf
);
681 kfree(head
->write_buf
);
684 spin_unlock(&tomoyo_io_buffer_list_lock
);
686 mutex_unlock(&tomoyo_gc_mutex
);
688 /* This acts as do_exit(0). */
693 * tomoyo_notify_gc - Register/unregister /sys/kernel/security/tomoyo/ users.
695 * @head: Pointer to "struct tomoyo_io_buffer".
696 * @is_register: True if register, false if unregister.
700 void tomoyo_notify_gc(struct tomoyo_io_buffer
*head
, const bool is_register
)
702 bool is_write
= false;
704 spin_lock(&tomoyo_io_buffer_list_lock
);
707 list_add(&head
->list
, &tomoyo_io_buffer_list
);
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
);
717 spin_unlock(&tomoyo_io_buffer_list_lock
);
719 struct task_struct
*task
= kthread_create(tomoyo_gc_thread
,
723 wake_up_process(task
);