Commit | Line | Data |
---|---|---|
847b173e TH |
1 | /* |
2 | * security/tomoyo/gc.c | |
3 | * | |
0f2a55d5 | 4 | * Copyright (C) 2005-2011 NTT DATA CORPORATION |
847b173e TH |
5 | */ |
6 | ||
7 | #include "common.h" | |
8 | #include <linux/kthread.h> | |
5a0e3ad6 | 9 | #include <linux/slab.h> |
847b173e | 10 | |
2e503bbb TH |
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); | |
15 | ||
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), | |
2066a361 | 25 | /* [TOMOYO_ID_CONDITION] = "struct tomoyo_condition"->size, */ |
2e503bbb TH |
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. */ | |
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), | |
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 | */ | |
49 | static 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); | |
66 | out: | |
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 | */ | |
85 | static 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); | |
108 | out: | |
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. */ | |
e2bf6907 | 119 | struct tomoyo_gc { |
847b173e | 120 | struct list_head list; |
0df7e8b8 | 121 | enum tomoyo_policy_id type; |
2e503bbb | 122 | size_t size; |
e79acf0e | 123 | struct list_head *element; |
847b173e | 124 | }; |
2e503bbb TH |
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; | |
847b173e | 129 | |
0df7e8b8 TH |
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 | */ | |
e79acf0e | 148 | static bool tomoyo_add_to_gc(const int type, struct list_head *element) |
847b173e | 149 | { |
e2bf6907 | 150 | struct tomoyo_gc *entry = kzalloc(sizeof(*entry), GFP_ATOMIC); |
847b173e TH |
151 | if (!entry) |
152 | return false; | |
153 | entry->type = type; | |
2e503bbb TH |
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; | |
2066a361 TH |
163 | else if (type == TOMOYO_ID_CONDITION) |
164 | entry->size = | |
165 | container_of(element, typeof(struct tomoyo_condition), | |
166 | head.list)->size; | |
2e503bbb TH |
167 | else |
168 | entry->size = tomoyo_element_size[type]; | |
847b173e | 169 | entry->element = element; |
2e503bbb | 170 | list_add(&entry->list, &tomoyo_gc_list); |
e79acf0e | 171 | list_del_rcu(element); |
2e503bbb TH |
172 | return tomoyo_gc_list_len++ < 128; |
173 | } | |
174 | ||
175 | /** | |
176 | * tomoyo_element_linked_by_gc - Validate next element of an entry. | |
177 | * | |
178 | * @element: Pointer to an element. | |
179 | * @size: Size of @element in byte. | |
180 | * | |
181 | * Returns true if @element is linked by other elements in the garbage | |
182 | * collector's queue, false otherwise. | |
183 | */ | |
184 | static bool tomoyo_element_linked_by_gc(const u8 *element, const size_t size) | |
185 | { | |
186 | struct tomoyo_gc *p; | |
187 | list_for_each_entry(p, &tomoyo_gc_list, list) { | |
188 | const u8 *ptr = (const u8 *) p->element->next; | |
189 | if (ptr < element || element + size < ptr) | |
190 | continue; | |
191 | return true; | |
192 | } | |
193 | return false; | |
847b173e TH |
194 | } |
195 | ||
0df7e8b8 TH |
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 | */ | |
5448ec4f | 203 | static void tomoyo_del_transition_control(struct list_head *element) |
847b173e | 204 | { |
5448ec4f | 205 | struct tomoyo_transition_control *ptr = |
e79acf0e | 206 | container_of(element, typeof(*ptr), head.list); |
847b173e TH |
207 | tomoyo_put_name(ptr->domainname); |
208 | tomoyo_put_name(ptr->program); | |
209 | } | |
210 | ||
0df7e8b8 TH |
211 | /** |
212 | * tomoyo_del_aggregator - Delete members in "struct tomoyo_aggregator". | |
213 | * | |
214 | * @element: Pointer to "struct list_head". | |
215 | * | |
216 | * Returns nothing. | |
217 | */ | |
e79acf0e | 218 | static void tomoyo_del_aggregator(struct list_head *element) |
1084307c | 219 | { |
e2bf6907 | 220 | struct tomoyo_aggregator *ptr = |
e79acf0e | 221 | container_of(element, typeof(*ptr), head.list); |
1084307c TH |
222 | tomoyo_put_name(ptr->original_name); |
223 | tomoyo_put_name(ptr->aggregated_name); | |
224 | } | |
225 | ||
0df7e8b8 TH |
226 | /** |
227 | * tomoyo_del_manager - Delete members in "struct tomoyo_manager". | |
228 | * | |
229 | * @element: Pointer to "struct list_head". | |
230 | * | |
231 | * Returns nothing. | |
232 | */ | |
e79acf0e | 233 | static void tomoyo_del_manager(struct list_head *element) |
847b173e | 234 | { |
e2bf6907 | 235 | struct tomoyo_manager *ptr = |
e79acf0e | 236 | container_of(element, typeof(*ptr), head.list); |
847b173e TH |
237 | tomoyo_put_name(ptr->manager); |
238 | } | |
239 | ||
0df7e8b8 TH |
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 | */ | |
e79acf0e | 247 | static void tomoyo_del_acl(struct list_head *element) |
847b173e | 248 | { |
e79acf0e TH |
249 | struct tomoyo_acl_info *acl = |
250 | container_of(element, typeof(*acl), list); | |
2066a361 | 251 | tomoyo_put_condition(acl->cond); |
847b173e | 252 | switch (acl->type) { |
7ef61233 | 253 | case TOMOYO_TYPE_PATH_ACL: |
847b173e | 254 | { |
7ef61233 | 255 | struct tomoyo_path_acl *entry |
847b173e | 256 | = container_of(acl, typeof(*entry), head); |
7762fbff | 257 | tomoyo_put_name_union(&entry->name); |
847b173e TH |
258 | } |
259 | break; | |
7ef61233 | 260 | case TOMOYO_TYPE_PATH2_ACL: |
847b173e | 261 | { |
7ef61233 | 262 | struct tomoyo_path2_acl *entry |
847b173e | 263 | = container_of(acl, typeof(*entry), head); |
7762fbff TH |
264 | tomoyo_put_name_union(&entry->name1); |
265 | tomoyo_put_name_union(&entry->name2); | |
847b173e TH |
266 | } |
267 | break; | |
a1f9bb6a TH |
268 | case TOMOYO_TYPE_PATH_NUMBER_ACL: |
269 | { | |
270 | struct tomoyo_path_number_acl *entry | |
271 | = container_of(acl, typeof(*entry), head); | |
272 | tomoyo_put_name_union(&entry->name); | |
273 | tomoyo_put_number_union(&entry->number); | |
274 | } | |
275 | break; | |
75093152 | 276 | case TOMOYO_TYPE_MKDEV_ACL: |
a1f9bb6a | 277 | { |
75093152 | 278 | struct tomoyo_mkdev_acl *entry |
a1f9bb6a TH |
279 | = container_of(acl, typeof(*entry), head); |
280 | tomoyo_put_name_union(&entry->name); | |
281 | tomoyo_put_number_union(&entry->mode); | |
282 | tomoyo_put_number_union(&entry->major); | |
283 | tomoyo_put_number_union(&entry->minor); | |
284 | } | |
285 | break; | |
2106ccd9 TH |
286 | case TOMOYO_TYPE_MOUNT_ACL: |
287 | { | |
288 | struct tomoyo_mount_acl *entry | |
289 | = container_of(acl, typeof(*entry), head); | |
290 | tomoyo_put_name_union(&entry->dev_name); | |
291 | tomoyo_put_name_union(&entry->dir_name); | |
292 | tomoyo_put_name_union(&entry->fs_type); | |
293 | tomoyo_put_number_union(&entry->flags); | |
294 | } | |
295 | break; | |
847b173e TH |
296 | } |
297 | } | |
298 | ||
2e503bbb TH |
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 | */ | |
e79acf0e | 306 | static bool tomoyo_del_domain(struct list_head *element) |
847b173e | 307 | { |
e79acf0e TH |
308 | struct tomoyo_domain_info *domain = |
309 | container_of(element, typeof(*domain), list); | |
847b173e TH |
310 | struct tomoyo_acl_info *acl; |
311 | struct tomoyo_acl_info *tmp; | |
312 | /* | |
313 | * Since we don't protect whole execve() operation using SRCU, | |
314 | * we need to recheck domain->users at this point. | |
315 | * | |
316 | * (1) Reader starts SRCU section upon execve(). | |
317 | * (2) Reader traverses tomoyo_domain_list and finds this domain. | |
318 | * (3) Writer marks this domain as deleted. | |
319 | * (4) Garbage collector removes this domain from tomoyo_domain_list | |
320 | * because this domain is marked as deleted and used by nobody. | |
321 | * (5) Reader saves reference to this domain into | |
322 | * "struct linux_binprm"->cred->security . | |
323 | * (6) Reader finishes SRCU section, although execve() operation has | |
324 | * not finished yet. | |
325 | * (7) Garbage collector waits for SRCU synchronization. | |
326 | * (8) Garbage collector kfree() this domain because this domain is | |
327 | * used by nobody. | |
328 | * (9) Reader finishes execve() operation and restores this domain from | |
329 | * "struct linux_binprm"->cred->security. | |
330 | * | |
331 | * By updating domain->users at (5), we can solve this race problem | |
332 | * by rechecking domain->users at (8). | |
333 | */ | |
334 | if (atomic_read(&domain->users)) | |
335 | return false; | |
336 | list_for_each_entry_safe(acl, tmp, &domain->acl_info_list, list) { | |
e79acf0e | 337 | tomoyo_del_acl(&acl->list); |
847b173e TH |
338 | tomoyo_memory_free(acl); |
339 | } | |
340 | tomoyo_put_name(domain->domainname); | |
341 | return true; | |
342 | } | |
343 | ||
2066a361 TH |
344 | /** |
345 | * tomoyo_del_condition - Delete members in "struct tomoyo_condition". | |
346 | * | |
347 | * @element: Pointer to "struct list_head". | |
348 | * | |
349 | * Returns nothing. | |
350 | */ | |
351 | void 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; | |
2ca9bf45 | 357 | const u16 names_count = cond->names_count; |
5b636857 TH |
358 | const u16 argc = cond->argc; |
359 | const u16 envc = cond->envc; | |
2066a361 TH |
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); | |
2ca9bf45 TH |
365 | struct tomoyo_name_union *names_p |
366 | = (struct tomoyo_name_union *) (numbers_p + numbers_count); | |
5b636857 TH |
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); | |
2066a361 TH |
371 | for (i = 0; i < numbers_count; i++) |
372 | tomoyo_put_number_union(numbers_p++); | |
2ca9bf45 TH |
373 | for (i = 0; i < names_count; i++) |
374 | tomoyo_put_name_union(names_p++); | |
5b636857 TH |
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 | } | |
2066a361 | 381 | } |
847b173e | 382 | |
0df7e8b8 TH |
383 | /** |
384 | * tomoyo_del_name - Delete members in "struct tomoyo_name". | |
385 | * | |
386 | * @element: Pointer to "struct list_head". | |
387 | * | |
388 | * Returns nothing. | |
389 | */ | |
e79acf0e | 390 | static void tomoyo_del_name(struct list_head *element) |
847b173e | 391 | { |
e2bf6907 | 392 | const struct tomoyo_name *ptr = |
0df7e8b8 | 393 | container_of(element, typeof(*ptr), head.list); |
847b173e TH |
394 | } |
395 | ||
0df7e8b8 TH |
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 | */ | |
a98aa4de | 403 | static void tomoyo_del_path_group(struct list_head *element) |
7762fbff | 404 | { |
a98aa4de | 405 | struct tomoyo_path_group *member = |
e79acf0e | 406 | container_of(element, typeof(*member), head.list); |
7762fbff TH |
407 | tomoyo_put_name(member->member_name); |
408 | } | |
409 | ||
0df7e8b8 TH |
410 | /** |
411 | * tomoyo_del_group - Delete "struct tomoyo_group". | |
412 | * | |
413 | * @element: Pointer to "struct list_head". | |
414 | * | |
415 | * Returns nothing. | |
416 | */ | |
a98aa4de | 417 | static void tomoyo_del_group(struct list_head *element) |
7762fbff | 418 | { |
a98aa4de | 419 | struct tomoyo_group *group = |
0df7e8b8 | 420 | container_of(element, typeof(*group), head.list); |
7762fbff TH |
421 | tomoyo_put_name(group->group_name); |
422 | } | |
423 | ||
0df7e8b8 TH |
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 | */ | |
e79acf0e | 431 | static void tomoyo_del_number_group(struct list_head *element) |
4c3e9e2d | 432 | { |
a98aa4de TH |
433 | struct tomoyo_number_group *member = |
434 | container_of(element, typeof(*member), head.list); | |
4c3e9e2d TH |
435 | } |
436 | ||
0df7e8b8 TH |
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 | */ | |
445 | static bool tomoyo_collect_member(const enum tomoyo_policy_id id, | |
446 | struct list_head *member_list) | |
d2f8b234 TH |
447 | { |
448 | struct tomoyo_acl_head *member; | |
449 | list_for_each_entry(member, member_list, list) { | |
450 | if (!member->is_deleted) | |
451 | continue; | |
452 | if (!tomoyo_add_to_gc(id, &member->list)) | |
453 | return false; | |
d2f8b234 | 454 | } |
0f2a55d5 | 455 | return true; |
d2f8b234 TH |
456 | } |
457 | ||
32997144 TH |
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 | */ | |
465 | static bool tomoyo_collect_acl(struct list_head *list) | |
d2f8b234 TH |
466 | { |
467 | struct tomoyo_acl_info *acl; | |
32997144 | 468 | list_for_each_entry(acl, list, list) { |
d2f8b234 TH |
469 | if (!acl->is_deleted) |
470 | continue; | |
471 | if (!tomoyo_add_to_gc(TOMOYO_ID_ACL, &acl->list)) | |
472 | return false; | |
d2f8b234 TH |
473 | } |
474 | return true; | |
475 | } | |
476 | ||
0df7e8b8 TH |
477 | /** |
478 | * tomoyo_collect_entry - Scan lists for deleted elements. | |
479 | * | |
480 | * Returns nothing. | |
481 | */ | |
847b173e TH |
482 | static void tomoyo_collect_entry(void) |
483 | { | |
d2f8b234 | 484 | int i; |
bd03a3e4 TH |
485 | enum tomoyo_policy_id id; |
486 | struct tomoyo_policy_namespace *ns; | |
487 | int idx; | |
29282381 TH |
488 | if (mutex_lock_interruptible(&tomoyo_policy_lock)) |
489 | return; | |
bd03a3e4 | 490 | idx = tomoyo_read_lock(); |
847b173e TH |
491 | { |
492 | struct tomoyo_domain_info *domain; | |
493 | list_for_each_entry_rcu(domain, &tomoyo_domain_list, list) { | |
32997144 | 494 | if (!tomoyo_collect_acl(&domain->acl_info_list)) |
d2f8b234 | 495 | goto unlock; |
847b173e TH |
496 | if (!domain->is_deleted || atomic_read(&domain->users)) |
497 | continue; | |
498 | /* | |
499 | * Nobody is referring this domain. But somebody may | |
500 | * refer this domain after successful execve(). | |
501 | * We recheck domain->users after SRCU synchronization. | |
502 | */ | |
e79acf0e | 503 | if (!tomoyo_add_to_gc(TOMOYO_ID_DOMAIN, &domain->list)) |
d2f8b234 | 504 | goto unlock; |
847b173e TH |
505 | } |
506 | } | |
bd03a3e4 TH |
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])) | |
d2f8b234 | 510 | goto unlock; |
bd03a3e4 TH |
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 | } | |
847b173e TH |
536 | } |
537 | } | |
2066a361 TH |
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]; | |
bd03a3e4 TH |
542 | struct tomoyo_shared_acl_head *ptr; |
543 | list_for_each_entry(ptr, list, list) { | |
544 | if (atomic_read(&ptr->users)) | |
4c3e9e2d | 545 | continue; |
2066a361 | 546 | if (!tomoyo_add_to_gc(id, &ptr->list)) |
d2f8b234 | 547 | goto unlock; |
4c3e9e2d | 548 | } |
2066a361 | 549 | id = TOMOYO_ID_NAME; |
4c3e9e2d | 550 | } |
bd03a3e4 TH |
551 | unlock: |
552 | tomoyo_read_unlock(idx); | |
29282381 | 553 | mutex_unlock(&tomoyo_policy_lock); |
847b173e TH |
554 | } |
555 | ||
2e503bbb TH |
556 | /** |
557 | * tomoyo_kfree_entry - Delete entries in tomoyo_gc_list. | |
558 | * | |
559 | * Returns true if some entries were kfree()d, false otherwise. | |
560 | */ | |
561 | static bool tomoyo_kfree_entry(void) | |
847b173e | 562 | { |
e2bf6907 TH |
563 | struct tomoyo_gc *p; |
564 | struct tomoyo_gc *tmp; | |
2e503bbb | 565 | bool result = false; |
847b173e | 566 | |
2e503bbb | 567 | list_for_each_entry_safe(p, tmp, &tomoyo_gc_list, list) { |
e79acf0e | 568 | struct list_head *element = p->element; |
2e503bbb TH |
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; | |
847b173e | 594 | switch (p->type) { |
5448ec4f TH |
595 | case TOMOYO_ID_TRANSITION_CONTROL: |
596 | tomoyo_del_transition_control(element); | |
847b173e | 597 | break; |
1084307c | 598 | case TOMOYO_ID_AGGREGATOR: |
e79acf0e | 599 | tomoyo_del_aggregator(element); |
1084307c | 600 | break; |
847b173e | 601 | case TOMOYO_ID_MANAGER: |
e79acf0e | 602 | tomoyo_del_manager(element); |
847b173e | 603 | break; |
2066a361 TH |
604 | case TOMOYO_ID_CONDITION: |
605 | tomoyo_del_condition(element); | |
606 | break; | |
847b173e | 607 | case TOMOYO_ID_NAME: |
2e503bbb TH |
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; | |
e79acf0e | 616 | tomoyo_del_name(element); |
847b173e TH |
617 | break; |
618 | case TOMOYO_ID_ACL: | |
e79acf0e | 619 | tomoyo_del_acl(element); |
847b173e TH |
620 | break; |
621 | case TOMOYO_ID_DOMAIN: | |
e79acf0e | 622 | if (!tomoyo_del_domain(element)) |
847b173e TH |
623 | continue; |
624 | break; | |
7762fbff | 625 | case TOMOYO_ID_PATH_GROUP: |
e79acf0e | 626 | tomoyo_del_path_group(element); |
7762fbff | 627 | break; |
a98aa4de TH |
628 | case TOMOYO_ID_GROUP: |
629 | tomoyo_del_group(element); | |
4c3e9e2d TH |
630 | break; |
631 | case TOMOYO_ID_NUMBER_GROUP: | |
e79acf0e | 632 | tomoyo_del_number_group(element); |
847b173e | 633 | break; |
0df7e8b8 TH |
634 | case TOMOYO_MAX_POLICY: |
635 | break; | |
847b173e | 636 | } |
e79acf0e | 637 | tomoyo_memory_free(element); |
847b173e TH |
638 | list_del(&p->list); |
639 | kfree(p); | |
2e503bbb TH |
640 | tomoyo_gc_list_len--; |
641 | result = true; | |
847b173e | 642 | } |
2e503bbb | 643 | return result; |
847b173e TH |
644 | } |
645 | ||
0df7e8b8 TH |
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 | */ | |
847b173e TH |
657 | static int tomoyo_gc_thread(void *unused) |
658 | { | |
2e503bbb TH |
659 | /* Garbage collector thread is exclusive. */ |
660 | static DEFINE_MUTEX(tomoyo_gc_mutex); | |
661 | if (!mutex_trylock(&tomoyo_gc_mutex)) | |
662 | goto out; | |
847b173e | 663 | daemonize("GC for TOMOYO"); |
2e503bbb TH |
664 | do { |
665 | tomoyo_collect_entry(); | |
666 | if (list_empty(&tomoyo_gc_list)) | |
667 | break; | |
668 | synchronize_srcu(&tomoyo_ss); | |
669 | } while (tomoyo_kfree_entry()); | |
670 | { | |
671 | struct tomoyo_io_buffer *head; | |
672 | struct tomoyo_io_buffer *tmp; | |
673 | ||
674 | spin_lock(&tomoyo_io_buffer_list_lock); | |
675 | list_for_each_entry_safe(head, tmp, &tomoyo_io_buffer_list, | |
676 | list) { | |
677 | if (head->users) | |
678 | continue; | |
679 | list_del(&head->list); | |
680 | kfree(head->read_buf); | |
681 | kfree(head->write_buf); | |
682 | kfree(head); | |
847b173e | 683 | } |
2e503bbb | 684 | spin_unlock(&tomoyo_io_buffer_list_lock); |
847b173e | 685 | } |
2e503bbb TH |
686 | mutex_unlock(&tomoyo_gc_mutex); |
687 | out: | |
688 | /* This acts as do_exit(0). */ | |
689 | return 0; | |
847b173e TH |
690 | } |
691 | ||
2e503bbb TH |
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 | */ | |
700 | void tomoyo_notify_gc(struct tomoyo_io_buffer *head, const bool is_register) | |
847b173e | 701 | { |
2e503bbb TH |
702 | bool is_write = false; |
703 | ||
704 | spin_lock(&tomoyo_io_buffer_list_lock); | |
705 | if (is_register) { | |
706 | head->users = 1; | |
707 | list_add(&head->list, &tomoyo_io_buffer_list); | |
708 | } else { | |
709 | is_write = head->write_buf != NULL; | |
710 | if (!--head->users) { | |
711 | list_del(&head->list); | |
712 | kfree(head->read_buf); | |
713 | kfree(head->write_buf); | |
714 | kfree(head); | |
715 | } | |
716 | } | |
717 | spin_unlock(&tomoyo_io_buffer_list_lock); | |
718 | if (is_write) { | |
719 | struct task_struct *task = kthread_create(tomoyo_gc_thread, | |
720 | NULL, | |
721 | "GC for TOMOYO"); | |
722 | if (!IS_ERR(task)) | |
723 | wake_up_process(task); | |
724 | } | |
847b173e | 725 | } |