~ [ source navigation ] ~ [ diff markup ] ~ [ identifier search ] ~

TOMOYO Linux Cross Reference
Linux/security/tomoyo/gc.c

Version: ~ [ linux-5.1-rc5 ] ~ [ linux-5.0.7 ] ~ [ linux-4.20.17 ] ~ [ linux-4.19.34 ] ~ [ linux-4.18.20 ] ~ [ linux-4.17.19 ] ~ [ linux-4.16.18 ] ~ [ linux-4.15.18 ] ~ [ linux-4.14.111 ] ~ [ linux-4.13.16 ] ~ [ linux-4.12.14 ] ~ [ linux-4.11.12 ] ~ [ linux-4.10.17 ] ~ [ linux-4.9.168 ] ~ [ linux-4.8.17 ] ~ [ linux-4.7.10 ] ~ [ linux-4.6.7 ] ~ [ linux-4.5.7 ] ~ [ linux-4.4.178 ] ~ [ linux-4.3.6 ] ~ [ linux-4.2.8 ] ~ [ linux-4.1.52 ] ~ [ linux-4.0.9 ] ~ [ linux-3.19.8 ] ~ [ linux-3.18.138 ] ~ [ linux-3.17.8 ] ~ [ linux-3.16.65 ] ~ [ linux-3.15.10 ] ~ [ linux-3.14.79 ] ~ [ linux-3.13.11 ] ~ [ linux-3.12.74 ] ~ [ linux-3.11.10 ] ~ [ linux-3.10.108 ] ~ [ linux-3.9.11 ] ~ [ linux-3.8.13 ] ~ [ linux-3.7.10 ] ~ [ linux-3.6.11 ] ~ [ linux-3.5.7 ] ~ [ linux-3.4.113 ] ~ [ linux-3.3.8 ] ~ [ linux-3.2.102 ] ~ [ linux-3.1.10 ] ~ [ linux-3.0.101 ] ~ [ linux-2.6.39.4 ] ~ [ linux-2.6.38.8 ] ~ [ linux-2.6.37.6 ] ~ [ linux-2.6.36.4 ] ~ [ linux-2.6.35.14 ] ~ [ linux-2.6.34.15 ] ~ [ linux-2.6.33.20 ] ~ [ linux-2.6.32.71 ] ~ [ linux-2.6.0 ] ~ [ linux-2.4.37.11 ] ~ [ unix-v6-master ] ~ [ ccs-tools-1.8.5 ] ~ [ policy-sample ] ~
Architecture: ~ [ i386 ] ~ [ alpha ] ~ [ m68k ] ~ [ mips ] ~ [ ppc ] ~ [ sparc ] ~ [ sparc64 ] ~

  1 /*
  2  * security/tomoyo/gc.c
  3  *
  4  * Implementation of the Domain-Based Mandatory Access Control.
  5  *
  6  * Copyright (C) 2005-2010  NTT DATA CORPORATION
  7  *
  8  */
  9 
 10 #include "common.h"
 11 #include <linux/kthread.h>
 12 #include <linux/slab.h>
 13 
 14 struct tomoyo_gc {
 15         struct list_head list;
 16         int type;
 17         struct list_head *element;
 18 };
 19 static LIST_HEAD(tomoyo_gc_queue);
 20 static DEFINE_MUTEX(tomoyo_gc_mutex);
 21 
 22 /* Caller holds tomoyo_policy_lock mutex. */
 23 static bool tomoyo_add_to_gc(const int type, struct list_head *element)
 24 {
 25         struct tomoyo_gc *entry = kzalloc(sizeof(*entry), GFP_ATOMIC);
 26         if (!entry)
 27                 return false;
 28         entry->type = type;
 29         entry->element = element;
 30         list_add(&entry->list, &tomoyo_gc_queue);
 31         list_del_rcu(element);
 32         return true;
 33 }
 34 
 35 static void tomoyo_del_allow_read(struct list_head *element)
 36 {
 37         struct tomoyo_readable_file *ptr =
 38                 container_of(element, typeof(*ptr), head.list);
 39         tomoyo_put_name(ptr->filename);
 40 }
 41 
 42 static void tomoyo_del_file_pattern(struct list_head *element)
 43 {
 44         struct tomoyo_no_pattern *ptr =
 45                 container_of(element, typeof(*ptr), head.list);
 46         tomoyo_put_name(ptr->pattern);
 47 }
 48 
 49 static void tomoyo_del_no_rewrite(struct list_head *element)
 50 {
 51         struct tomoyo_no_rewrite *ptr =
 52                 container_of(element, typeof(*ptr), head.list);
 53         tomoyo_put_name(ptr->pattern);
 54 }
 55 
 56 static void tomoyo_del_transition_control(struct list_head *element)
 57 {
 58         struct tomoyo_transition_control *ptr =
 59                 container_of(element, typeof(*ptr), head.list);
 60         tomoyo_put_name(ptr->domainname);
 61         tomoyo_put_name(ptr->program);
 62 }
 63 
 64 static void tomoyo_del_aggregator(struct list_head *element)
 65 {
 66         struct tomoyo_aggregator *ptr =
 67                 container_of(element, typeof(*ptr), head.list);
 68         tomoyo_put_name(ptr->original_name);
 69         tomoyo_put_name(ptr->aggregated_name);
 70 }
 71 
 72 static void tomoyo_del_manager(struct list_head *element)
 73 {
 74         struct tomoyo_manager *ptr =
 75                 container_of(element, typeof(*ptr), head.list);
 76         tomoyo_put_name(ptr->manager);
 77 }
 78 
 79 static void tomoyo_del_acl(struct list_head *element)
 80 {
 81         struct tomoyo_acl_info *acl =
 82                 container_of(element, typeof(*acl), list);
 83         switch (acl->type) {
 84         case TOMOYO_TYPE_PATH_ACL:
 85                 {
 86                         struct tomoyo_path_acl *entry
 87                                 = container_of(acl, typeof(*entry), head);
 88                         tomoyo_put_name_union(&entry->name);
 89                 }
 90                 break;
 91         case TOMOYO_TYPE_PATH2_ACL:
 92                 {
 93                         struct tomoyo_path2_acl *entry
 94                                 = container_of(acl, typeof(*entry), head);
 95                         tomoyo_put_name_union(&entry->name1);
 96                         tomoyo_put_name_union(&entry->name2);
 97                 }
 98                 break;
 99         case TOMOYO_TYPE_PATH_NUMBER_ACL:
100                 {
101                         struct tomoyo_path_number_acl *entry
102                                 = container_of(acl, typeof(*entry), head);
103                         tomoyo_put_name_union(&entry->name);
104                         tomoyo_put_number_union(&entry->number);
105                 }
106                 break;
107         case TOMOYO_TYPE_MKDEV_ACL:
108                 {
109                         struct tomoyo_mkdev_acl *entry
110                                 = container_of(acl, typeof(*entry), head);
111                         tomoyo_put_name_union(&entry->name);
112                         tomoyo_put_number_union(&entry->mode);
113                         tomoyo_put_number_union(&entry->major);
114                         tomoyo_put_number_union(&entry->minor);
115                 }
116                 break;
117         case TOMOYO_TYPE_MOUNT_ACL:
118                 {
119                         struct tomoyo_mount_acl *entry
120                                 = container_of(acl, typeof(*entry), head);
121                         tomoyo_put_name_union(&entry->dev_name);
122                         tomoyo_put_name_union(&entry->dir_name);
123                         tomoyo_put_name_union(&entry->fs_type);
124                         tomoyo_put_number_union(&entry->flags);
125                 }
126                 break;
127         }
128 }
129 
130 static bool tomoyo_del_domain(struct list_head *element)
131 {
132         struct tomoyo_domain_info *domain =
133                 container_of(element, typeof(*domain), list);
134         struct tomoyo_acl_info *acl;
135         struct tomoyo_acl_info *tmp;
136         /*
137          * Since we don't protect whole execve() operation using SRCU,
138          * we need to recheck domain->users at this point.
139          *
140          * (1) Reader starts SRCU section upon execve().
141          * (2) Reader traverses tomoyo_domain_list and finds this domain.
142          * (3) Writer marks this domain as deleted.
143          * (4) Garbage collector removes this domain from tomoyo_domain_list
144          *     because this domain is marked as deleted and used by nobody.
145          * (5) Reader saves reference to this domain into
146          *     "struct linux_binprm"->cred->security .
147          * (6) Reader finishes SRCU section, although execve() operation has
148          *     not finished yet.
149          * (7) Garbage collector waits for SRCU synchronization.
150          * (8) Garbage collector kfree() this domain because this domain is
151          *     used by nobody.
152          * (9) Reader finishes execve() operation and restores this domain from
153          *     "struct linux_binprm"->cred->security.
154          *
155          * By updating domain->users at (5), we can solve this race problem
156          * by rechecking domain->users at (8).
157          */
158         if (atomic_read(&domain->users))
159                 return false;
160         list_for_each_entry_safe(acl, tmp, &domain->acl_info_list, list) {
161                 tomoyo_del_acl(&acl->list);
162                 tomoyo_memory_free(acl);
163         }
164         tomoyo_put_name(domain->domainname);
165         return true;
166 }
167 
168 
169 static void tomoyo_del_name(struct list_head *element)
170 {
171         const struct tomoyo_name *ptr =
172                 container_of(element, typeof(*ptr), list);
173 }
174 
175 static void tomoyo_del_path_group(struct list_head *element)
176 {
177         struct tomoyo_path_group *member =
178                 container_of(element, typeof(*member), head.list);
179         tomoyo_put_name(member->member_name);
180 }
181 
182 static void tomoyo_del_group(struct list_head *element)
183 {
184         struct tomoyo_group *group =
185                 container_of(element, typeof(*group), list);
186         tomoyo_put_name(group->group_name);
187 }
188 
189 static void tomoyo_del_number_group(struct list_head *element)
190 {
191         struct tomoyo_number_group *member =
192                 container_of(element, typeof(*member), head.list);
193 }
194 
195 static bool tomoyo_collect_member(struct list_head *member_list, int id)
196 {
197         struct tomoyo_acl_head *member;
198         list_for_each_entry(member, member_list, list) {
199                 if (!member->is_deleted)
200                         continue;
201                 if (!tomoyo_add_to_gc(id, &member->list))
202                         return false;
203         }
204         return true;
205 }
206 
207 static bool tomoyo_collect_acl(struct tomoyo_domain_info *domain)
208 {
209         struct tomoyo_acl_info *acl;
210         list_for_each_entry(acl, &domain->acl_info_list, list) {
211                 if (!acl->is_deleted)
212                         continue;
213                 if (!tomoyo_add_to_gc(TOMOYO_ID_ACL, &acl->list))
214                         return false;
215         }
216         return true;
217 }
218 
219 static void tomoyo_collect_entry(void)
220 {
221         int i;
222         if (mutex_lock_interruptible(&tomoyo_policy_lock))
223                 return;
224         for (i = 0; i < TOMOYO_MAX_POLICY; i++) {
225                 if (!tomoyo_collect_member(&tomoyo_policy_list[i], i))
226                         goto unlock;
227         }
228         {
229                 struct tomoyo_domain_info *domain;
230                 list_for_each_entry_rcu(domain, &tomoyo_domain_list, list) {
231                         if (!tomoyo_collect_acl(domain))
232                                 goto unlock;
233                         if (!domain->is_deleted || atomic_read(&domain->users))
234                                 continue;
235                         /*
236                          * Nobody is referring this domain. But somebody may
237                          * refer this domain after successful execve().
238                          * We recheck domain->users after SRCU synchronization.
239                          */
240                         if (!tomoyo_add_to_gc(TOMOYO_ID_DOMAIN, &domain->list))
241                                 goto unlock;
242                 }
243         }
244         for (i = 0; i < TOMOYO_MAX_HASH; i++) {
245                 struct tomoyo_name *ptr;
246                 list_for_each_entry_rcu(ptr, &tomoyo_name_list[i], list) {
247                         if (atomic_read(&ptr->users))
248                                 continue;
249                         if (!tomoyo_add_to_gc(TOMOYO_ID_NAME, &ptr->list))
250                                 goto unlock;
251                 }
252         }
253         for (i = 0; i < TOMOYO_MAX_GROUP; i++) {
254                 struct list_head *list = &tomoyo_group_list[i];
255                 int id;
256                 struct tomoyo_group *group;
257                 switch (i) {
258                 case 0:
259                         id = TOMOYO_ID_PATH_GROUP;
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;
271                         if (!tomoyo_add_to_gc(TOMOYO_ID_GROUP, &group->list))
272                                 goto unlock;
273                 }
274         }
275  unlock:
276         mutex_unlock(&tomoyo_policy_lock);
277 }
278 
279 static void tomoyo_kfree_entry(void)
280 {
281         struct tomoyo_gc *p;
282         struct tomoyo_gc *tmp;
283 
284         list_for_each_entry_safe(p, tmp, &tomoyo_gc_queue, list) {
285                 struct list_head *element = p->element;
286                 switch (p->type) {
287                 case TOMOYO_ID_TRANSITION_CONTROL:
288                         tomoyo_del_transition_control(element);
289                         break;
290                 case TOMOYO_ID_AGGREGATOR:
291                         tomoyo_del_aggregator(element);
292                         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:
303                         tomoyo_del_manager(element);
304                         break;
305                 case TOMOYO_ID_NAME:
306                         tomoyo_del_name(element);
307                         break;
308                 case TOMOYO_ID_ACL:
309                         tomoyo_del_acl(element);
310                         break;
311                 case TOMOYO_ID_DOMAIN:
312                         if (!tomoyo_del_domain(element))
313                                 continue;
314                         break;
315                 case TOMOYO_ID_PATH_GROUP:
316                         tomoyo_del_path_group(element);
317                         break;
318                 case TOMOYO_ID_GROUP:
319                         tomoyo_del_group(element);
320                         break;
321                 case TOMOYO_ID_NUMBER_GROUP:
322                         tomoyo_del_number_group(element);
323                         break;
324                 }
325                 tomoyo_memory_free(element);
326                 list_del(&p->list);
327                 kfree(p);
328         }
329 }
330 
331 static int tomoyo_gc_thread(void *unused)
332 {
333         daemonize("GC for TOMOYO");
334         if (mutex_trylock(&tomoyo_gc_mutex)) {
335                 int i;
336                 for (i = 0; i < 10; i++) {
337                         tomoyo_collect_entry();
338                         if (list_empty(&tomoyo_gc_queue))
339                                 break;
340                         synchronize_srcu(&tomoyo_ss);
341                         tomoyo_kfree_entry();
342                 }
343                 mutex_unlock(&tomoyo_gc_mutex);
344         }
345         do_exit(0);
346 }
347 
348 void tomoyo_run_gc(void)
349 {
350         struct task_struct *task = kthread_create(tomoyo_gc_thread, NULL,
351                                                   "GC for TOMOYO");
352         if (!IS_ERR(task))
353                 wake_up_process(task);
354 }
355 

~ [ source navigation ] ~ [ diff markup ] ~ [ identifier search ] ~

kernel.org | git.kernel.org | LWN.net | Project Home | Wiki (Japanese) | Wiki (English) | SVN repository | Mail admin

Linux® is a registered trademark of Linus Torvalds in the United States and other countries.
TOMOYO® is a registered trademark of NTT DATA CORPORATION.

osdn.jp