aboutsummaryrefslogtreecommitdiffstats
path: root/security/tomoyo/gc.c
diff options
context:
space:
mode:
Diffstat (limited to 'security/tomoyo/gc.c')
-rw-r--r--security/tomoyo/gc.c551
1 files changed, 461 insertions, 90 deletions
diff --git a/security/tomoyo/gc.c b/security/tomoyo/gc.c
index a877e4c3b101..ae135fbbbe95 100644
--- a/security/tomoyo/gc.c
+++ b/security/tomoyo/gc.c
@@ -1,58 +1,205 @@
1/* 1/*
2 * security/tomoyo/gc.c 2 * security/tomoyo/gc.c
3 * 3 *
4 * Implementation of the Domain-Based Mandatory Access Control. 4 * Copyright (C) 2005-2011 NTT DATA CORPORATION
5 *
6 * Copyright (C) 2005-2010 NTT DATA CORPORATION
7 *
8 */ 5 */
9 6
10#include "common.h" 7#include "common.h"
11#include <linux/kthread.h> 8#include <linux/kthread.h>
12#include <linux/slab.h> 9#include <linux/slab.h>
13 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. */
14struct tomoyo_gc { 119struct tomoyo_gc {
15 struct list_head list; 120 struct list_head list;
16 int type; 121 enum tomoyo_policy_id type;
122 size_t size;
17 struct list_head *element; 123 struct list_head *element;
18}; 124};
19static LIST_HEAD(tomoyo_gc_queue); 125/* List of entries to be deleted. */
20static DEFINE_MUTEX(tomoyo_gc_mutex); 126static LIST_HEAD(tomoyo_gc_list);
127/* Length of tomoyo_gc_list. */
128static int tomoyo_gc_list_len;
21 129
22/* Caller holds tomoyo_policy_lock mutex. */ 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 */
23static bool tomoyo_add_to_gc(const int type, struct list_head *element) 148static bool tomoyo_add_to_gc(const int type, struct list_head *element)
24{ 149{
25 struct tomoyo_gc *entry = kzalloc(sizeof(*entry), GFP_ATOMIC); 150 struct tomoyo_gc *entry = kzalloc(sizeof(*entry), GFP_ATOMIC);
26 if (!entry) 151 if (!entry)
27 return false; 152 return false;
28 entry->type = type; 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];
29 entry->element = element; 169 entry->element = element;
30 list_add(&entry->list, &tomoyo_gc_queue); 170 list_add(&entry->list, &tomoyo_gc_list);
31 list_del_rcu(element); 171 list_del_rcu(element);
32 return true; 172 return tomoyo_gc_list_len++ < 128;
33} 173}
34 174
35static void tomoyo_del_allow_read(struct list_head *element) 175/**
36{ 176 * tomoyo_element_linked_by_gc - Validate next element of an entry.
37 struct tomoyo_readable_file *ptr = 177 *
38 container_of(element, typeof(*ptr), head.list); 178 * @element: Pointer to an element.
39 tomoyo_put_name(ptr->filename); 179 * @size: Size of @element in byte.
40} 180 *
41 181 * Returns true if @element is linked by other elements in the garbage
42static void tomoyo_del_file_pattern(struct list_head *element) 182 * collector's queue, false otherwise.
43{ 183 */
44 struct tomoyo_no_pattern *ptr = 184static bool tomoyo_element_linked_by_gc(const u8 *element, const size_t size)
45 container_of(element, typeof(*ptr), head.list);
46 tomoyo_put_name(ptr->pattern);
47}
48
49static void tomoyo_del_no_rewrite(struct list_head *element)
50{ 185{
51 struct tomoyo_no_rewrite *ptr = 186 struct tomoyo_gc *p;
52 container_of(element, typeof(*ptr), head.list); 187 list_for_each_entry(p, &tomoyo_gc_list, list) {
53 tomoyo_put_name(ptr->pattern); 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;
54} 194}
55 195
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 */
56static void tomoyo_del_transition_control(struct list_head *element) 203static void tomoyo_del_transition_control(struct list_head *element)
57{ 204{
58 struct tomoyo_transition_control *ptr = 205 struct tomoyo_transition_control *ptr =
@@ -61,6 +208,13 @@ static void tomoyo_del_transition_control(struct list_head *element)
61 tomoyo_put_name(ptr->program); 208 tomoyo_put_name(ptr->program);
62} 209}
63 210
211/**
212 * tomoyo_del_aggregator - Delete members in "struct tomoyo_aggregator".
213 *
214 * @element: Pointer to "struct list_head".
215 *
216 * Returns nothing.
217 */
64static void tomoyo_del_aggregator(struct list_head *element) 218static void tomoyo_del_aggregator(struct list_head *element)
65{ 219{
66 struct tomoyo_aggregator *ptr = 220 struct tomoyo_aggregator *ptr =
@@ -69,6 +223,13 @@ static void tomoyo_del_aggregator(struct list_head *element)
69 tomoyo_put_name(ptr->aggregated_name); 223 tomoyo_put_name(ptr->aggregated_name);
70} 224}
71 225
226/**
227 * tomoyo_del_manager - Delete members in "struct tomoyo_manager".
228 *
229 * @element: Pointer to "struct list_head".
230 *
231 * Returns nothing.
232 */
72static void tomoyo_del_manager(struct list_head *element) 233static void tomoyo_del_manager(struct list_head *element)
73{ 234{
74 struct tomoyo_manager *ptr = 235 struct tomoyo_manager *ptr =
@@ -76,10 +237,18 @@ static void tomoyo_del_manager(struct list_head *element)
76 tomoyo_put_name(ptr->manager); 237 tomoyo_put_name(ptr->manager);
77} 238}
78 239
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 */
79static void tomoyo_del_acl(struct list_head *element) 247static void tomoyo_del_acl(struct list_head *element)
80{ 248{
81 struct tomoyo_acl_info *acl = 249 struct tomoyo_acl_info *acl =
82 container_of(element, typeof(*acl), list); 250 container_of(element, typeof(*acl), list);
251 tomoyo_put_condition(acl->cond);
83 switch (acl->type) { 252 switch (acl->type) {
84 case TOMOYO_TYPE_PATH_ACL: 253 case TOMOYO_TYPE_PATH_ACL:
85 { 254 {
@@ -127,6 +296,13 @@ static void tomoyo_del_acl(struct list_head *element)
127 } 296 }
128} 297}
129 298
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 */
130static bool tomoyo_del_domain(struct list_head *element) 306static bool tomoyo_del_domain(struct list_head *element)
131{ 307{
132 struct tomoyo_domain_info *domain = 308 struct tomoyo_domain_info *domain =
@@ -165,13 +341,65 @@ static bool tomoyo_del_domain(struct list_head *element)
165 return true; 341 return true;
166} 342}
167 343
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}
168 382
383/**
384 * tomoyo_del_name - Delete members in "struct tomoyo_name".
385 *
386 * @element: Pointer to "struct list_head".
387 *
388 * Returns nothing.
389 */
169static void tomoyo_del_name(struct list_head *element) 390static void tomoyo_del_name(struct list_head *element)
170{ 391{
171 const struct tomoyo_name *ptr = 392 const struct tomoyo_name *ptr =
172 container_of(element, typeof(*ptr), list); 393 container_of(element, typeof(*ptr), head.list);
173} 394}
174 395
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 */
175static void tomoyo_del_path_group(struct list_head *element) 403static void tomoyo_del_path_group(struct list_head *element)
176{ 404{
177 struct tomoyo_path_group *member = 405 struct tomoyo_path_group *member =
@@ -179,20 +407,43 @@ static void tomoyo_del_path_group(struct list_head *element)
179 tomoyo_put_name(member->member_name); 407 tomoyo_put_name(member->member_name);
180} 408}
181 409
410/**
411 * tomoyo_del_group - Delete "struct tomoyo_group".
412 *
413 * @element: Pointer to "struct list_head".
414 *
415 * Returns nothing.
416 */
182static void tomoyo_del_group(struct list_head *element) 417static void tomoyo_del_group(struct list_head *element)
183{ 418{
184 struct tomoyo_group *group = 419 struct tomoyo_group *group =
185 container_of(element, typeof(*group), list); 420 container_of(element, typeof(*group), head.list);
186 tomoyo_put_name(group->group_name); 421 tomoyo_put_name(group->group_name);
187} 422}
188 423
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 */
189static void tomoyo_del_number_group(struct list_head *element) 431static void tomoyo_del_number_group(struct list_head *element)
190{ 432{
191 struct tomoyo_number_group *member = 433 struct tomoyo_number_group *member =
192 container_of(element, typeof(*member), head.list); 434 container_of(element, typeof(*member), head.list);
193} 435}
194 436
195static bool tomoyo_collect_member(struct list_head *member_list, int id) 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)
196{ 447{
197 struct tomoyo_acl_head *member; 448 struct tomoyo_acl_head *member;
198 list_for_each_entry(member, member_list, list) { 449 list_for_each_entry(member, member_list, list) {
@@ -201,13 +452,20 @@ static bool tomoyo_collect_member(struct list_head *member_list, int id)
201 if (!tomoyo_add_to_gc(id, &member->list)) 452 if (!tomoyo_add_to_gc(id, &member->list))
202 return false; 453 return false;
203 } 454 }
204 return true; 455 return true;
205} 456}
206 457
207static bool tomoyo_collect_acl(struct tomoyo_domain_info *domain) 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)
208{ 466{
209 struct tomoyo_acl_info *acl; 467 struct tomoyo_acl_info *acl;
210 list_for_each_entry(acl, &domain->acl_info_list, list) { 468 list_for_each_entry(acl, list, list) {
211 if (!acl->is_deleted) 469 if (!acl->is_deleted)
212 continue; 470 continue;
213 if (!tomoyo_add_to_gc(TOMOYO_ID_ACL, &acl->list)) 471 if (!tomoyo_add_to_gc(TOMOYO_ID_ACL, &acl->list))
@@ -216,19 +474,24 @@ static bool tomoyo_collect_acl(struct tomoyo_domain_info *domain)
216 return true; 474 return true;
217} 475}
218 476
477/**
478 * tomoyo_collect_entry - Scan lists for deleted elements.
479 *
480 * Returns nothing.
481 */
219static void tomoyo_collect_entry(void) 482static void tomoyo_collect_entry(void)
220{ 483{
221 int i; 484 int i;
485 enum tomoyo_policy_id id;
486 struct tomoyo_policy_namespace *ns;
487 int idx;
222 if (mutex_lock_interruptible(&tomoyo_policy_lock)) 488 if (mutex_lock_interruptible(&tomoyo_policy_lock))
223 return; 489 return;
224 for (i = 0; i < TOMOYO_MAX_POLICY; i++) { 490 idx = tomoyo_read_lock();
225 if (!tomoyo_collect_member(&tomoyo_policy_list[i], i))
226 goto unlock;
227 }
228 { 491 {
229 struct tomoyo_domain_info *domain; 492 struct tomoyo_domain_info *domain;
230 list_for_each_entry_rcu(domain, &tomoyo_domain_list, list) { 493 list_for_each_entry_rcu(domain, &tomoyo_domain_list, list) {
231 if (!tomoyo_collect_acl(domain)) 494 if (!tomoyo_collect_acl(&domain->acl_info_list))
232 goto unlock; 495 goto unlock;
233 if (!domain->is_deleted || atomic_read(&domain->users)) 496 if (!domain->is_deleted || atomic_read(&domain->users))
234 continue; 497 continue;
@@ -241,48 +504,93 @@ static void tomoyo_collect_entry(void)
241 goto unlock; 504 goto unlock;
242 } 505 }
243 } 506 }
244 for (i = 0; i < TOMOYO_MAX_HASH; i++) { 507 list_for_each_entry_rcu(ns, &tomoyo_namespace_list, namespace_list) {
245 struct tomoyo_name *ptr; 508 for (id = 0; id < TOMOYO_MAX_POLICY; id++)
246 list_for_each_entry_rcu(ptr, &tomoyo_name_list[i], list) { 509 if (!tomoyo_collect_member(id, &ns->policy_list[id]))
247 if (atomic_read(&ptr->users))
248 continue;
249 if (!tomoyo_add_to_gc(TOMOYO_ID_NAME, &ptr->list))
250 goto unlock; 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 }
251 } 536 }
252 } 537 }
253 for (i = 0; i < TOMOYO_MAX_GROUP; i++) { 538 id = TOMOYO_ID_CONDITION;
254 struct list_head *list = &tomoyo_group_list[i]; 539 for (i = 0; i < TOMOYO_MAX_HASH + 1; i++) {
255 int id; 540 struct list_head *list = !i ?
256 struct tomoyo_group *group; 541 &tomoyo_condition_list : &tomoyo_name_list[i - 1];
257 switch (i) { 542 struct tomoyo_shared_acl_head *ptr;
258 case 0: 543 list_for_each_entry(ptr, list, list) {
259 id = TOMOYO_ID_PATH_GROUP; 544 if (atomic_read(&ptr->users))
260 break;
261 default:
262 id = TOMOYO_ID_NUMBER_GROUP;
263 break;
264 }
265 list_for_each_entry(group, list, list) {
266 if (!tomoyo_collect_member(&group->member_list, id))
267 goto unlock;
268 if (!list_empty(&group->member_list) ||
269 atomic_read(&group->users))
270 continue; 545 continue;
271 if (!tomoyo_add_to_gc(TOMOYO_ID_GROUP, &group->list)) 546 if (!tomoyo_add_to_gc(id, &ptr->list))
272 goto unlock; 547 goto unlock;
273 } 548 }
549 id = TOMOYO_ID_NAME;
274 } 550 }
275 unlock: 551unlock:
552 tomoyo_read_unlock(idx);
276 mutex_unlock(&tomoyo_policy_lock); 553 mutex_unlock(&tomoyo_policy_lock);
277} 554}
278 555
279static void tomoyo_kfree_entry(void) 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)
280{ 562{
281 struct tomoyo_gc *p; 563 struct tomoyo_gc *p;
282 struct tomoyo_gc *tmp; 564 struct tomoyo_gc *tmp;
565 bool result = false;
283 566
284 list_for_each_entry_safe(p, tmp, &tomoyo_gc_queue, list) { 567 list_for_each_entry_safe(p, tmp, &tomoyo_gc_list, list) {
285 struct list_head *element = p->element; 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;
286 switch (p->type) { 594 switch (p->type) {
287 case TOMOYO_ID_TRANSITION_CONTROL: 595 case TOMOYO_ID_TRANSITION_CONTROL:
288 tomoyo_del_transition_control(element); 596 tomoyo_del_transition_control(element);
@@ -290,19 +598,21 @@ static void tomoyo_kfree_entry(void)
290 case TOMOYO_ID_AGGREGATOR: 598 case TOMOYO_ID_AGGREGATOR:
291 tomoyo_del_aggregator(element); 599 tomoyo_del_aggregator(element);
292 break; 600 break;
293 case TOMOYO_ID_GLOBALLY_READABLE:
294 tomoyo_del_allow_read(element);
295 break;
296 case TOMOYO_ID_PATTERN:
297 tomoyo_del_file_pattern(element);
298 break;
299 case TOMOYO_ID_NO_REWRITE:
300 tomoyo_del_no_rewrite(element);
301 break;
302 case TOMOYO_ID_MANAGER: 601 case TOMOYO_ID_MANAGER:
303 tomoyo_del_manager(element); 602 tomoyo_del_manager(element);
304 break; 603 break;
604 case TOMOYO_ID_CONDITION:
605 tomoyo_del_condition(element);
606 break;
305 case TOMOYO_ID_NAME: 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;
306 tomoyo_del_name(element); 616 tomoyo_del_name(element);
307 break; 617 break;
308 case TOMOYO_ID_ACL: 618 case TOMOYO_ID_ACL:
@@ -321,34 +631,95 @@ static void tomoyo_kfree_entry(void)
321 case TOMOYO_ID_NUMBER_GROUP: 631 case TOMOYO_ID_NUMBER_GROUP:
322 tomoyo_del_number_group(element); 632 tomoyo_del_number_group(element);
323 break; 633 break;
634 case TOMOYO_MAX_POLICY:
635 break;
324 } 636 }
325 tomoyo_memory_free(element); 637 tomoyo_memory_free(element);
326 list_del(&p->list); 638 list_del(&p->list);
327 kfree(p); 639 kfree(p);
640 tomoyo_gc_list_len--;
641 result = true;
328 } 642 }
643 return result;
329} 644}
330 645
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 */
331static int tomoyo_gc_thread(void *unused) 657static int tomoyo_gc_thread(void *unused)
332{ 658{
659 /* Garbage collector thread is exclusive. */
660 static DEFINE_MUTEX(tomoyo_gc_mutex);
661 if (!mutex_trylock(&tomoyo_gc_mutex))
662 goto out;
333 daemonize("GC for TOMOYO"); 663 daemonize("GC for TOMOYO");
334 if (mutex_trylock(&tomoyo_gc_mutex)) { 664 do {
335 int i; 665 tomoyo_collect_entry();
336 for (i = 0; i < 10; i++) { 666 if (list_empty(&tomoyo_gc_list))
337 tomoyo_collect_entry(); 667 break;
338 if (list_empty(&tomoyo_gc_queue)) 668 synchronize_srcu(&tomoyo_ss);
339 break; 669 } while (tomoyo_kfree_entry());
340 synchronize_srcu(&tomoyo_ss); 670 {
341 tomoyo_kfree_entry(); 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);
342 } 683 }
343 mutex_unlock(&tomoyo_gc_mutex); 684 spin_unlock(&tomoyo_io_buffer_list_lock);
344 } 685 }
345 do_exit(0); 686 mutex_unlock(&tomoyo_gc_mutex);
687out:
688 /* This acts as do_exit(0). */
689 return 0;
346} 690}
347 691
348void tomoyo_run_gc(void) 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)
349{ 701{
350 struct task_struct *task = kthread_create(tomoyo_gc_thread, NULL, 702 bool is_write = false;
351 "GC for TOMOYO"); 703
352 if (!IS_ERR(task)) 704 spin_lock(&tomoyo_io_buffer_list_lock);
353 wake_up_process(task); 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 }
354} 725}
generated by cgit v1.2.2 (git 2.25.0) at 2025-04-25 04:03:06 -0400