4 * Implementation of the Domain-Based Mandatory Access Control.
6 * Copyright (C) 2005-2010 NTT DATA CORPORATION
11 #include <linux/kthread.h>
14 TOMOYO_ID_DOMAIN_INITIALIZER,
15 TOMOYO_ID_DOMAIN_KEEPER,
17 TOMOYO_ID_GLOBALLY_READABLE,
26 struct tomoyo_gc_entry {
27 struct list_head list;
31 static LIST_HEAD(tomoyo_gc_queue);
32 static DEFINE_MUTEX(tomoyo_gc_mutex);
34 /* Caller holds tomoyo_policy_lock mutex. */
35 static bool tomoyo_add_to_gc(const int type, void *element)
37 struct tomoyo_gc_entry *entry = kzalloc(sizeof(*entry), GFP_ATOMIC);
41 entry->element = element;
42 list_add(&entry->list, &tomoyo_gc_queue);
46 static void tomoyo_del_allow_read
47 (struct tomoyo_globally_readable_file_entry *ptr)
49 tomoyo_put_name(ptr->filename);
52 static void tomoyo_del_file_pattern(struct tomoyo_pattern_entry *ptr)
54 tomoyo_put_name(ptr->pattern);
57 static void tomoyo_del_no_rewrite(struct tomoyo_no_rewrite_entry *ptr)
59 tomoyo_put_name(ptr->pattern);
62 static void tomoyo_del_domain_initializer
63 (struct tomoyo_domain_initializer_entry *ptr)
65 tomoyo_put_name(ptr->domainname);
66 tomoyo_put_name(ptr->program);
69 static void tomoyo_del_domain_keeper(struct tomoyo_domain_keeper_entry *ptr)
71 tomoyo_put_name(ptr->domainname);
72 tomoyo_put_name(ptr->program);
75 static void tomoyo_del_alias(struct tomoyo_alias_entry *ptr)
77 tomoyo_put_name(ptr->original_name);
78 tomoyo_put_name(ptr->aliased_name);
81 static void tomoyo_del_manager(struct tomoyo_policy_manager_entry *ptr)
83 tomoyo_put_name(ptr->manager);
86 static void tomoyo_del_acl(struct tomoyo_acl_info *acl)
89 case TOMOYO_TYPE_PATH_ACL:
91 struct tomoyo_path_acl *entry
92 = container_of(acl, typeof(*entry), head);
93 tomoyo_put_name(entry->filename);
96 case TOMOYO_TYPE_PATH2_ACL:
98 struct tomoyo_path2_acl *entry
99 = container_of(acl, typeof(*entry), head);
100 tomoyo_put_name(entry->filename1);
101 tomoyo_put_name(entry->filename2);
105 printk(KERN_WARNING "Unknown type\n");
110 static bool tomoyo_del_domain(struct tomoyo_domain_info *domain)
112 struct tomoyo_acl_info *acl;
113 struct tomoyo_acl_info *tmp;
115 * Since we don't protect whole execve() operation using SRCU,
116 * we need to recheck domain->users at this point.
118 * (1) Reader starts SRCU section upon execve().
119 * (2) Reader traverses tomoyo_domain_list and finds this domain.
120 * (3) Writer marks this domain as deleted.
121 * (4) Garbage collector removes this domain from tomoyo_domain_list
122 * because this domain is marked as deleted and used by nobody.
123 * (5) Reader saves reference to this domain into
124 * "struct linux_binprm"->cred->security .
125 * (6) Reader finishes SRCU section, although execve() operation has
127 * (7) Garbage collector waits for SRCU synchronization.
128 * (8) Garbage collector kfree() this domain because this domain is
130 * (9) Reader finishes execve() operation and restores this domain from
131 * "struct linux_binprm"->cred->security.
133 * By updating domain->users at (5), we can solve this race problem
134 * by rechecking domain->users at (8).
136 if (atomic_read(&domain->users))
138 list_for_each_entry_safe(acl, tmp, &domain->acl_info_list, list) {
140 tomoyo_memory_free(acl);
142 tomoyo_put_name(domain->domainname);
147 static void tomoyo_del_name(const struct tomoyo_name_entry *ptr)
151 static void tomoyo_collect_entry(void)
153 mutex_lock(&tomoyo_policy_lock);
155 struct tomoyo_globally_readable_file_entry *ptr;
156 list_for_each_entry_rcu(ptr, &tomoyo_globally_readable_list,
158 if (!ptr->is_deleted)
160 if (tomoyo_add_to_gc(TOMOYO_ID_GLOBALLY_READABLE, ptr))
161 list_del_rcu(&ptr->list);
167 struct tomoyo_pattern_entry *ptr;
168 list_for_each_entry_rcu(ptr, &tomoyo_pattern_list, list) {
169 if (!ptr->is_deleted)
171 if (tomoyo_add_to_gc(TOMOYO_ID_PATTERN, ptr))
172 list_del_rcu(&ptr->list);
178 struct tomoyo_no_rewrite_entry *ptr;
179 list_for_each_entry_rcu(ptr, &tomoyo_no_rewrite_list, list) {
180 if (!ptr->is_deleted)
182 if (tomoyo_add_to_gc(TOMOYO_ID_NO_REWRITE, ptr))
183 list_del_rcu(&ptr->list);
189 struct tomoyo_domain_initializer_entry *ptr;
190 list_for_each_entry_rcu(ptr, &tomoyo_domain_initializer_list,
192 if (!ptr->is_deleted)
194 if (tomoyo_add_to_gc(TOMOYO_ID_DOMAIN_INITIALIZER, ptr))
195 list_del_rcu(&ptr->list);
201 struct tomoyo_domain_keeper_entry *ptr;
202 list_for_each_entry_rcu(ptr, &tomoyo_domain_keeper_list, list) {
203 if (!ptr->is_deleted)
205 if (tomoyo_add_to_gc(TOMOYO_ID_DOMAIN_KEEPER, ptr))
206 list_del_rcu(&ptr->list);
212 struct tomoyo_alias_entry *ptr;
213 list_for_each_entry_rcu(ptr, &tomoyo_alias_list, list) {
214 if (!ptr->is_deleted)
216 if (tomoyo_add_to_gc(TOMOYO_ID_ALIAS, ptr))
217 list_del_rcu(&ptr->list);
223 struct tomoyo_policy_manager_entry *ptr;
224 list_for_each_entry_rcu(ptr, &tomoyo_policy_manager_list,
226 if (!ptr->is_deleted)
228 if (tomoyo_add_to_gc(TOMOYO_ID_MANAGER, ptr))
229 list_del_rcu(&ptr->list);
235 struct tomoyo_domain_info *domain;
236 list_for_each_entry_rcu(domain, &tomoyo_domain_list, list) {
237 struct tomoyo_acl_info *acl;
238 list_for_each_entry_rcu(acl, &domain->acl_info_list,
241 case TOMOYO_TYPE_PATH_ACL:
242 if (container_of(acl,
243 struct tomoyo_path_acl,
246 struct tomoyo_path_acl,
250 case TOMOYO_TYPE_PATH2_ACL:
251 if (container_of(acl,
252 struct tomoyo_path2_acl,
259 if (tomoyo_add_to_gc(TOMOYO_ID_ACL, acl))
260 list_del_rcu(&acl->list);
264 if (!domain->is_deleted || atomic_read(&domain->users))
267 * Nobody is referring this domain. But somebody may
268 * refer this domain after successful execve().
269 * We recheck domain->users after SRCU synchronization.
271 if (tomoyo_add_to_gc(TOMOYO_ID_DOMAIN, domain))
272 list_del_rcu(&domain->list);
277 mutex_unlock(&tomoyo_policy_lock);
278 mutex_lock(&tomoyo_name_list_lock);
281 for (i = 0; i < TOMOYO_MAX_HASH; i++) {
282 struct tomoyo_name_entry *ptr;
283 list_for_each_entry_rcu(ptr, &tomoyo_name_list[i],
285 if (atomic_read(&ptr->users))
287 if (tomoyo_add_to_gc(TOMOYO_ID_NAME, ptr))
288 list_del_rcu(&ptr->list);
296 mutex_unlock(&tomoyo_name_list_lock);
299 static void tomoyo_kfree_entry(void)
301 struct tomoyo_gc_entry *p;
302 struct tomoyo_gc_entry *tmp;
304 list_for_each_entry_safe(p, tmp, &tomoyo_gc_queue, list) {
306 case TOMOYO_ID_DOMAIN_INITIALIZER:
307 tomoyo_del_domain_initializer(p->element);
309 case TOMOYO_ID_DOMAIN_KEEPER:
310 tomoyo_del_domain_keeper(p->element);
312 case TOMOYO_ID_ALIAS:
313 tomoyo_del_alias(p->element);
315 case TOMOYO_ID_GLOBALLY_READABLE:
316 tomoyo_del_allow_read(p->element);
318 case TOMOYO_ID_PATTERN:
319 tomoyo_del_file_pattern(p->element);
321 case TOMOYO_ID_NO_REWRITE:
322 tomoyo_del_no_rewrite(p->element);
324 case TOMOYO_ID_MANAGER:
325 tomoyo_del_manager(p->element);
328 tomoyo_del_name(p->element);
331 tomoyo_del_acl(p->element);
333 case TOMOYO_ID_DOMAIN:
334 if (!tomoyo_del_domain(p->element))
338 printk(KERN_WARNING "Unknown type\n");
341 tomoyo_memory_free(p->element);
347 static int tomoyo_gc_thread(void *unused)
349 daemonize("GC for TOMOYO");
350 if (mutex_trylock(&tomoyo_gc_mutex)) {
352 for (i = 0; i < 10; i++) {
353 tomoyo_collect_entry();
354 if (list_empty(&tomoyo_gc_queue))
356 synchronize_srcu(&tomoyo_ss);
357 tomoyo_kfree_entry();
359 mutex_unlock(&tomoyo_gc_mutex);
364 void tomoyo_run_gc(void)
366 struct task_struct *task = kthread_create(tomoyo_gc_thread, NULL,
369 wake_up_process(task);