1 /* Basic authentication token and access key management
3 * Copyright (C) 2004-2008 Red Hat, Inc. All Rights Reserved.
4 * Written by David Howells (dhowells@redhat.com)
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public License
8 * as published by the Free Software Foundation; either version
9 * 2 of the License, or (at your option) any later version.
12 #include <linux/module.h>
13 #include <linux/init.h>
14 #include <linux/poison.h>
15 #include <linux/sched.h>
16 #include <linux/slab.h>
17 #include <linux/security.h>
18 #include <linux/workqueue.h>
19 #include <linux/random.h>
20 #include <linux/err.h>
21 #include <linux/user_namespace.h>
24 struct kmem_cache
*key_jar
;
25 struct rb_root key_serial_tree
; /* tree of keys indexed by serial */
26 DEFINE_SPINLOCK(key_serial_lock
);
28 struct rb_root key_user_tree
; /* tree of quota records indexed by UID */
29 DEFINE_SPINLOCK(key_user_lock
);
31 unsigned int key_quota_root_maxkeys
= 200; /* root's key count quota */
32 unsigned int key_quota_root_maxbytes
= 20000; /* root's key space quota */
33 unsigned int key_quota_maxkeys
= 200; /* general key count quota */
34 unsigned int key_quota_maxbytes
= 20000; /* general key space quota */
36 static LIST_HEAD(key_types_list
);
37 static DECLARE_RWSEM(key_types_sem
);
39 /* We serialise key instantiation and link */
40 DEFINE_MUTEX(key_construction_mutex
);
43 void __key_check(const struct key
*key
)
45 printk("__key_check: key %p {%08x} should be {%08x}\n",
46 key
, key
->magic
, KEY_DEBUG_MAGIC
);
52 * Get the key quota record for a user, allocating a new record if one doesn't
55 struct key_user
*key_user_lookup(uid_t uid
, struct user_namespace
*user_ns
)
57 struct key_user
*candidate
= NULL
, *user
;
58 struct rb_node
*parent
= NULL
;
62 p
= &key_user_tree
.rb_node
;
63 spin_lock(&key_user_lock
);
65 /* search the tree for a user record with a matching UID */
68 user
= rb_entry(parent
, struct key_user
, node
);
72 else if (uid
> user
->uid
)
74 else if (user_ns
< user
->user_ns
)
76 else if (user_ns
> user
->user_ns
)
82 /* if we get here, we failed to find a match in the tree */
84 /* allocate a candidate user record if we don't already have
86 spin_unlock(&key_user_lock
);
89 candidate
= kmalloc(sizeof(struct key_user
), GFP_KERNEL
);
90 if (unlikely(!candidate
))
93 /* the allocation may have scheduled, so we need to repeat the
94 * search lest someone else added the record whilst we were
99 /* if we get here, then the user record still hadn't appeared on the
100 * second pass - so we use the candidate record */
101 atomic_set(&candidate
->usage
, 1);
102 atomic_set(&candidate
->nkeys
, 0);
103 atomic_set(&candidate
->nikeys
, 0);
104 candidate
->uid
= uid
;
105 candidate
->user_ns
= get_user_ns(user_ns
);
106 candidate
->qnkeys
= 0;
107 candidate
->qnbytes
= 0;
108 spin_lock_init(&candidate
->lock
);
109 mutex_init(&candidate
->cons_lock
);
111 rb_link_node(&candidate
->node
, parent
, p
);
112 rb_insert_color(&candidate
->node
, &key_user_tree
);
113 spin_unlock(&key_user_lock
);
117 /* okay - we found a user record for this UID */
119 atomic_inc(&user
->usage
);
120 spin_unlock(&key_user_lock
);
127 * Dispose of a user structure
129 void key_user_put(struct key_user
*user
)
131 if (atomic_dec_and_lock(&user
->usage
, &key_user_lock
)) {
132 rb_erase(&user
->node
, &key_user_tree
);
133 spin_unlock(&key_user_lock
);
134 put_user_ns(user
->user_ns
);
141 * Allocate a serial number for a key. These are assigned randomly to avoid
142 * security issues through covert channel problems.
144 static inline void key_alloc_serial(struct key
*key
)
146 struct rb_node
*parent
, **p
;
149 /* propose a random serial number and look for a hole for it in the
150 * serial number tree */
152 get_random_bytes(&key
->serial
, sizeof(key
->serial
));
154 key
->serial
>>= 1; /* negative numbers are not permitted */
155 } while (key
->serial
< 3);
157 spin_lock(&key_serial_lock
);
161 p
= &key_serial_tree
.rb_node
;
165 xkey
= rb_entry(parent
, struct key
, serial_node
);
167 if (key
->serial
< xkey
->serial
)
169 else if (key
->serial
> xkey
->serial
)
175 /* we've found a suitable hole - arrange for this key to occupy it */
176 rb_link_node(&key
->serial_node
, parent
, p
);
177 rb_insert_color(&key
->serial_node
, &key_serial_tree
);
179 spin_unlock(&key_serial_lock
);
182 /* we found a key with the proposed serial number - walk the tree from
183 * that point looking for the next unused serial number */
187 if (key
->serial
< 3) {
189 goto attempt_insertion
;
192 parent
= rb_next(parent
);
194 goto attempt_insertion
;
196 xkey
= rb_entry(parent
, struct key
, serial_node
);
197 if (key
->serial
< xkey
->serial
)
198 goto attempt_insertion
;
203 * key_alloc - Allocate a key of the specified type.
204 * @type: The type of key to allocate.
205 * @desc: The key description to allow the key to be searched out.
206 * @uid: The owner of the new key.
207 * @gid: The group ID for the new key's group permissions.
208 * @cred: The credentials specifying UID namespace.
209 * @perm: The permissions mask of the new key.
210 * @flags: Flags specifying quota properties.
212 * Allocate a key of the specified type with the attributes given. The key is
213 * returned in an uninstantiated state and the caller needs to instantiate the
214 * key before returning.
216 * The user's key count quota is updated to reflect the creation of the key and
217 * the user's key data quota has the default for the key type reserved. The
218 * instantiation function should amend this as necessary. If insufficient
219 * quota is available, -EDQUOT will be returned.
221 * The LSM security modules can prevent a key being created, in which case
222 * -EACCES will be returned.
224 * Returns a pointer to the new key if successful and an error code otherwise.
226 * Note that the caller needs to ensure the key type isn't uninstantiated.
227 * Internally this can be done by locking key_types_sem. Externally, this can
228 * be done by either never unregistering the key type, or making sure
229 * key_alloc() calls don't race with module unloading.
231 struct key
*key_alloc(struct key_type
*type
, const char *desc
,
232 uid_t uid
, gid_t gid
, const struct cred
*cred
,
233 key_perm_t perm
, unsigned long flags
)
235 struct key_user
*user
= NULL
;
237 size_t desclen
, quotalen
;
240 key
= ERR_PTR(-EINVAL
);
244 if (type
->vet_description
) {
245 ret
= type
->vet_description(desc
);
252 desclen
= strlen(desc
) + 1;
253 quotalen
= desclen
+ type
->def_datalen
;
255 /* get hold of the key tracking for this user */
256 user
= key_user_lookup(uid
, cred
->user_ns
);
260 /* check that the user's quota permits allocation of another key and
262 if (!(flags
& KEY_ALLOC_NOT_IN_QUOTA
)) {
263 unsigned maxkeys
= (uid
== 0) ?
264 key_quota_root_maxkeys
: key_quota_maxkeys
;
265 unsigned maxbytes
= (uid
== 0) ?
266 key_quota_root_maxbytes
: key_quota_maxbytes
;
268 spin_lock(&user
->lock
);
269 if (!(flags
& KEY_ALLOC_QUOTA_OVERRUN
)) {
270 if (user
->qnkeys
+ 1 >= maxkeys
||
271 user
->qnbytes
+ quotalen
>= maxbytes
||
272 user
->qnbytes
+ quotalen
< user
->qnbytes
)
277 user
->qnbytes
+= quotalen
;
278 spin_unlock(&user
->lock
);
281 /* allocate and initialise the key and its description */
282 key
= kmem_cache_alloc(key_jar
, GFP_KERNEL
);
287 key
->description
= kmemdup(desc
, desclen
, GFP_KERNEL
);
288 if (!key
->description
)
292 atomic_set(&key
->usage
, 1);
293 init_rwsem(&key
->sem
);
294 lockdep_set_class(&key
->sem
, &type
->lock_class
);
297 key
->quotalen
= quotalen
;
298 key
->datalen
= type
->def_datalen
;
304 key
->payload
.data
= NULL
;
305 key
->security
= NULL
;
307 if (!(flags
& KEY_ALLOC_NOT_IN_QUOTA
))
308 key
->flags
|= 1 << KEY_FLAG_IN_QUOTA
;
310 memset(&key
->type_data
, 0, sizeof(key
->type_data
));
313 key
->magic
= KEY_DEBUG_MAGIC
;
316 /* let the security module know about the key */
317 ret
= security_key_alloc(key
, cred
, flags
);
321 /* publish the key by giving it a serial number */
322 atomic_inc(&user
->nkeys
);
323 key_alloc_serial(key
);
329 kfree(key
->description
);
330 kmem_cache_free(key_jar
, key
);
331 if (!(flags
& KEY_ALLOC_NOT_IN_QUOTA
)) {
332 spin_lock(&user
->lock
);
334 user
->qnbytes
-= quotalen
;
335 spin_unlock(&user
->lock
);
342 kmem_cache_free(key_jar
, key
);
344 if (!(flags
& KEY_ALLOC_NOT_IN_QUOTA
)) {
345 spin_lock(&user
->lock
);
347 user
->qnbytes
-= quotalen
;
348 spin_unlock(&user
->lock
);
352 key
= ERR_PTR(-ENOMEM
);
356 spin_unlock(&user
->lock
);
358 key
= ERR_PTR(-EDQUOT
);
361 EXPORT_SYMBOL(key_alloc
);
364 * key_payload_reserve - Adjust data quota reservation for the key's payload
365 * @key: The key to make the reservation for.
366 * @datalen: The amount of data payload the caller now wants.
368 * Adjust the amount of the owning user's key data quota that a key reserves.
369 * If the amount is increased, then -EDQUOT may be returned if there isn't
370 * enough free quota available.
372 * If successful, 0 is returned.
374 int key_payload_reserve(struct key
*key
, size_t datalen
)
376 int delta
= (int)datalen
- key
->datalen
;
381 /* contemplate the quota adjustment */
382 if (delta
!= 0 && test_bit(KEY_FLAG_IN_QUOTA
, &key
->flags
)) {
383 unsigned maxbytes
= (key
->user
->uid
== 0) ?
384 key_quota_root_maxbytes
: key_quota_maxbytes
;
386 spin_lock(&key
->user
->lock
);
389 (key
->user
->qnbytes
+ delta
>= maxbytes
||
390 key
->user
->qnbytes
+ delta
< key
->user
->qnbytes
)) {
394 key
->user
->qnbytes
+= delta
;
395 key
->quotalen
+= delta
;
397 spin_unlock(&key
->user
->lock
);
400 /* change the recorded data length if that didn't generate an error */
402 key
->datalen
= datalen
;
406 EXPORT_SYMBOL(key_payload_reserve
);
409 * Instantiate a key and link it into the target keyring atomically. Must be
410 * called with the target keyring's semaphore writelocked. The target key's
411 * semaphore need not be locked as instantiation is serialised by
412 * key_construction_mutex.
414 static int __key_instantiate_and_link(struct key
*key
,
419 unsigned long *_prealloc
)
429 mutex_lock(&key_construction_mutex
);
431 /* can't instantiate twice */
432 if (!test_bit(KEY_FLAG_INSTANTIATED
, &key
->flags
)) {
433 /* instantiate the key */
434 ret
= key
->type
->instantiate(key
, data
, datalen
);
437 /* mark the key as being instantiated */
438 atomic_inc(&key
->user
->nikeys
);
439 set_bit(KEY_FLAG_INSTANTIATED
, &key
->flags
);
441 if (test_and_clear_bit(KEY_FLAG_USER_CONSTRUCT
, &key
->flags
))
444 /* and link it into the destination keyring */
446 __key_link(keyring
, key
, _prealloc
);
448 /* disable the authorisation key */
454 mutex_unlock(&key_construction_mutex
);
456 /* wake up anyone waiting for a key to be constructed */
458 wake_up_bit(&key
->flags
, KEY_FLAG_USER_CONSTRUCT
);
464 * key_instantiate_and_link - Instantiate a key and link it into the keyring.
465 * @key: The key to instantiate.
466 * @data: The data to use to instantiate the keyring.
467 * @datalen: The length of @data.
468 * @keyring: Keyring to create a link in on success (or NULL).
469 * @authkey: The authorisation token permitting instantiation.
471 * Instantiate a key that's in the uninstantiated state using the provided data
472 * and, if successful, link it in to the destination keyring if one is
475 * If successful, 0 is returned, the authorisation token is revoked and anyone
476 * waiting for the key is woken up. If the key was already instantiated,
477 * -EBUSY will be returned.
479 int key_instantiate_and_link(struct key
*key
,
485 unsigned long prealloc
;
489 ret
= __key_link_begin(keyring
, key
->type
, key
->description
,
495 ret
= __key_instantiate_and_link(key
, data
, datalen
, keyring
, authkey
,
499 __key_link_end(keyring
, key
->type
, prealloc
);
504 EXPORT_SYMBOL(key_instantiate_and_link
);
507 * key_reject_and_link - Negatively instantiate a key and link it into the keyring.
508 * @key: The key to instantiate.
509 * @timeout: The timeout on the negative key.
510 * @error: The error to return when the key is hit.
511 * @keyring: Keyring to create a link in on success (or NULL).
512 * @authkey: The authorisation token permitting instantiation.
514 * Negatively instantiate a key that's in the uninstantiated state and, if
515 * successful, set its timeout and stored error and link it in to the
516 * destination keyring if one is supplied. The key and any links to the key
517 * will be automatically garbage collected after the timeout expires.
519 * Negative keys are used to rate limit repeated request_key() calls by causing
520 * them to return the stored error code (typically ENOKEY) until the negative
523 * If successful, 0 is returned, the authorisation token is revoked and anyone
524 * waiting for the key is woken up. If the key was already instantiated,
525 * -EBUSY will be returned.
527 int key_reject_and_link(struct key
*key
,
533 unsigned long prealloc
;
535 int ret
, awaken
, link_ret
= 0;
544 link_ret
= __key_link_begin(keyring
, key
->type
,
545 key
->description
, &prealloc
);
547 mutex_lock(&key_construction_mutex
);
549 /* can't instantiate twice */
550 if (!test_bit(KEY_FLAG_INSTANTIATED
, &key
->flags
)) {
551 /* mark the key as being negatively instantiated */
552 atomic_inc(&key
->user
->nikeys
);
553 set_bit(KEY_FLAG_NEGATIVE
, &key
->flags
);
554 set_bit(KEY_FLAG_INSTANTIATED
, &key
->flags
);
555 key
->type_data
.reject_error
= -error
;
556 now
= current_kernel_time();
557 key
->expiry
= now
.tv_sec
+ timeout
;
558 key_schedule_gc(key
->expiry
+ key_gc_delay
);
560 if (test_and_clear_bit(KEY_FLAG_USER_CONSTRUCT
, &key
->flags
))
565 /* and link it into the destination keyring */
566 if (keyring
&& link_ret
== 0)
567 __key_link(keyring
, key
, &prealloc
);
569 /* disable the authorisation key */
574 mutex_unlock(&key_construction_mutex
);
577 __key_link_end(keyring
, key
->type
, prealloc
);
579 /* wake up anyone waiting for a key to be constructed */
581 wake_up_bit(&key
->flags
, KEY_FLAG_USER_CONSTRUCT
);
583 return ret
== 0 ? link_ret
: ret
;
585 EXPORT_SYMBOL(key_reject_and_link
);
588 * key_put - Discard a reference to a key.
589 * @key: The key to discard a reference from.
591 * Discard a reference to a key, and when all the references are gone, we
592 * schedule the cleanup task to come and pull it out of the tree in process
593 * context at some later time.
595 void key_put(struct key
*key
)
600 if (atomic_dec_and_test(&key
->usage
))
601 queue_work(system_nrt_wq
, &key_gc_work
);
604 EXPORT_SYMBOL(key_put
);
607 * Find a key by its serial number.
609 struct key
*key_lookup(key_serial_t id
)
614 spin_lock(&key_serial_lock
);
616 /* search the tree for the specified key */
617 n
= key_serial_tree
.rb_node
;
619 key
= rb_entry(n
, struct key
, serial_node
);
621 if (id
< key
->serial
)
623 else if (id
> key
->serial
)
630 key
= ERR_PTR(-ENOKEY
);
634 /* pretend it doesn't exist if it is awaiting deletion */
635 if (atomic_read(&key
->usage
) == 0)
638 /* this races with key_put(), but that doesn't matter since key_put()
639 * doesn't actually change the key
641 atomic_inc(&key
->usage
);
644 spin_unlock(&key_serial_lock
);
649 * Find and lock the specified key type against removal.
651 * We return with the sem read-locked if successful. If the type wasn't
652 * available -ENOKEY is returned instead.
654 struct key_type
*key_type_lookup(const char *type
)
656 struct key_type
*ktype
;
658 down_read(&key_types_sem
);
660 /* look up the key type to see if it's one of the registered kernel
662 list_for_each_entry(ktype
, &key_types_list
, link
) {
663 if (strcmp(ktype
->name
, type
) == 0)
664 goto found_kernel_type
;
667 up_read(&key_types_sem
);
668 ktype
= ERR_PTR(-ENOKEY
);
674 void key_set_timeout(struct key
*key
, unsigned timeout
)
679 /* make the changes with the locks held to prevent races */
680 down_write(&key
->sem
);
683 now
= current_kernel_time();
684 expiry
= now
.tv_sec
+ timeout
;
687 key
->expiry
= expiry
;
688 key_schedule_gc(key
->expiry
+ key_gc_delay
);
692 EXPORT_SYMBOL_GPL(key_set_timeout
);
695 * Unlock a key type locked by key_type_lookup().
697 void key_type_put(struct key_type
*ktype
)
699 up_read(&key_types_sem
);
703 * Attempt to update an existing key.
705 * The key is given to us with an incremented refcount that we need to discard
706 * if we get an error.
708 static inline key_ref_t
__key_update(key_ref_t key_ref
,
709 const void *payload
, size_t plen
)
711 struct key
*key
= key_ref_to_ptr(key_ref
);
714 /* need write permission on the key to update it */
715 ret
= key_permission(key_ref
, KEY_WRITE
);
720 if (!key
->type
->update
)
723 down_write(&key
->sem
);
725 ret
= key
->type
->update(key
, payload
, plen
);
727 /* updating a negative key instantiates it */
728 clear_bit(KEY_FLAG_NEGATIVE
, &key
->flags
);
739 key_ref
= ERR_PTR(ret
);
744 * key_create_or_update - Update or create and instantiate a key.
745 * @keyring_ref: A pointer to the destination keyring with possession flag.
746 * @type: The type of key.
747 * @description: The searchable description for the key.
748 * @payload: The data to use to instantiate or update the key.
749 * @plen: The length of @payload.
750 * @perm: The permissions mask for a new key.
751 * @flags: The quota flags for a new key.
753 * Search the destination keyring for a key of the same description and if one
754 * is found, update it, otherwise create and instantiate a new one and create a
755 * link to it from that keyring.
757 * If perm is KEY_PERM_UNDEF then an appropriate key permissions mask will be
760 * Returns a pointer to the new key if successful, -ENODEV if the key type
761 * wasn't available, -ENOTDIR if the keyring wasn't a keyring, -EACCES if the
762 * caller isn't permitted to modify the keyring or the LSM did not permit
763 * creation of the key.
765 * On success, the possession flag from the keyring ref will be tacked on to
766 * the key ref before it is returned.
768 key_ref_t
key_create_or_update(key_ref_t keyring_ref
,
770 const char *description
,
776 unsigned long prealloc
;
777 const struct cred
*cred
= current_cred();
778 struct key_type
*ktype
;
779 struct key
*keyring
, *key
= NULL
;
783 /* look up the key type to see if it's one of the registered kernel
785 ktype
= key_type_lookup(type
);
787 key_ref
= ERR_PTR(-ENODEV
);
791 key_ref
= ERR_PTR(-EINVAL
);
792 if (!ktype
->match
|| !ktype
->instantiate
)
795 keyring
= key_ref_to_ptr(keyring_ref
);
799 key_ref
= ERR_PTR(-ENOTDIR
);
800 if (keyring
->type
!= &key_type_keyring
)
803 ret
= __key_link_begin(keyring
, ktype
, description
, &prealloc
);
807 /* if we're going to allocate a new key, we're going to have
808 * to modify the keyring */
809 ret
= key_permission(keyring_ref
, KEY_WRITE
);
811 key_ref
= ERR_PTR(ret
);
815 /* if it's possible to update this type of key, search for an existing
816 * key of the same type and description in the destination keyring and
817 * update that instead if possible
820 key_ref
= __keyring_search_one(keyring_ref
, ktype
, description
,
822 if (!IS_ERR(key_ref
))
823 goto found_matching_key
;
826 /* if the client doesn't provide, decide on the permissions we want */
827 if (perm
== KEY_PERM_UNDEF
) {
828 perm
= KEY_POS_VIEW
| KEY_POS_SEARCH
| KEY_POS_LINK
| KEY_POS_SETATTR
;
829 perm
|= KEY_USR_VIEW
| KEY_USR_SEARCH
| KEY_USR_LINK
| KEY_USR_SETATTR
;
832 perm
|= KEY_POS_READ
| KEY_USR_READ
;
834 if (ktype
== &key_type_keyring
|| ktype
->update
)
835 perm
|= KEY_USR_WRITE
;
838 /* allocate a new key */
839 key
= key_alloc(ktype
, description
, cred
->fsuid
, cred
->fsgid
, cred
,
842 key_ref
= ERR_CAST(key
);
846 /* instantiate it and link it into the target keyring */
847 ret
= __key_instantiate_and_link(key
, payload
, plen
, keyring
, NULL
,
851 key_ref
= ERR_PTR(ret
);
855 key_ref
= make_key_ref(key
, is_key_possessed(keyring_ref
));
858 __key_link_end(keyring
, ktype
, prealloc
);
865 /* we found a matching key, so we're going to try to update it
866 * - we can drop the locks first as we have the key pinned
868 __key_link_end(keyring
, ktype
, prealloc
);
871 key_ref
= __key_update(key_ref
, payload
, plen
);
874 EXPORT_SYMBOL(key_create_or_update
);
877 * key_update - Update a key's contents.
878 * @key_ref: The pointer (plus possession flag) to the key.
879 * @payload: The data to be used to update the key.
880 * @plen: The length of @payload.
882 * Attempt to update the contents of a key with the given payload data. The
883 * caller must be granted Write permission on the key. Negative keys can be
884 * instantiated by this method.
886 * Returns 0 on success, -EACCES if not permitted and -EOPNOTSUPP if the key
887 * type does not support updating. The key type may return other errors.
889 int key_update(key_ref_t key_ref
, const void *payload
, size_t plen
)
891 struct key
*key
= key_ref_to_ptr(key_ref
);
896 /* the key must be writable */
897 ret
= key_permission(key_ref
, KEY_WRITE
);
901 /* attempt to update it if supported */
903 if (key
->type
->update
) {
904 down_write(&key
->sem
);
906 ret
= key
->type
->update(key
, payload
, plen
);
908 /* updating a negative key instantiates it */
909 clear_bit(KEY_FLAG_NEGATIVE
, &key
->flags
);
917 EXPORT_SYMBOL(key_update
);
920 * key_revoke - Revoke a key.
921 * @key: The key to be revoked.
923 * Mark a key as being revoked and ask the type to free up its resources. The
924 * revocation timeout is set and the key and all its links will be
925 * automatically garbage collected after key_gc_delay amount of time if they
926 * are not manually dealt with first.
928 void key_revoke(struct key
*key
)
935 /* make sure no one's trying to change or use the key when we mark it
936 * - we tell lockdep that we might nest because we might be revoking an
937 * authorisation key whilst holding the sem on a key we've just
940 down_write_nested(&key
->sem
, 1);
941 if (!test_and_set_bit(KEY_FLAG_REVOKED
, &key
->flags
) &&
943 key
->type
->revoke(key
);
945 /* set the death time to no more than the expiry time */
946 now
= current_kernel_time();
948 if (key
->revoked_at
== 0 || key
->revoked_at
> time
) {
949 key
->revoked_at
= time
;
950 key_schedule_gc(key
->revoked_at
+ key_gc_delay
);
955 EXPORT_SYMBOL(key_revoke
);
958 * key_invalidate - Invalidate a key.
959 * @key: The key to be invalidated.
961 * Mark a key as being invalidated and have it cleaned up immediately. The key
962 * is ignored by all searches and other operations from this point.
964 void key_invalidate(struct key
*key
)
966 kenter("%d", key_serial(key
));
970 if (!test_bit(KEY_FLAG_INVALIDATED
, &key
->flags
)) {
971 down_write_nested(&key
->sem
, 1);
972 if (!test_and_set_bit(KEY_FLAG_INVALIDATED
, &key
->flags
))
973 key_schedule_gc_links();
977 EXPORT_SYMBOL(key_invalidate
);
980 * register_key_type - Register a type of key.
981 * @ktype: The new key type.
983 * Register a new key type.
985 * Returns 0 on success or -EEXIST if a type of this name already exists.
987 int register_key_type(struct key_type
*ktype
)
992 memset(&ktype
->lock_class
, 0, sizeof(ktype
->lock_class
));
995 down_write(&key_types_sem
);
997 /* disallow key types with the same name */
998 list_for_each_entry(p
, &key_types_list
, link
) {
999 if (strcmp(p
->name
, ktype
->name
) == 0)
1003 /* store the type */
1004 list_add(&ktype
->link
, &key_types_list
);
1006 pr_notice("Key type %s registered\n", ktype
->name
);
1010 up_write(&key_types_sem
);
1013 EXPORT_SYMBOL(register_key_type
);
1016 * unregister_key_type - Unregister a type of key.
1017 * @ktype: The key type.
1019 * Unregister a key type and mark all the extant keys of this type as dead.
1020 * Those keys of this type are then destroyed to get rid of their payloads and
1021 * they and their links will be garbage collected as soon as possible.
1023 void unregister_key_type(struct key_type
*ktype
)
1025 down_write(&key_types_sem
);
1026 list_del_init(&ktype
->link
);
1027 downgrade_write(&key_types_sem
);
1028 key_gc_keytype(ktype
);
1029 pr_notice("Key type %s unregistered\n", ktype
->name
);
1030 up_read(&key_types_sem
);
1032 EXPORT_SYMBOL(unregister_key_type
);
1035 * Initialise the key management state.
1037 void __init
key_init(void)
1039 /* allocate a slab in which we can store keys */
1040 key_jar
= kmem_cache_create("key_jar", sizeof(struct key
),
1041 0, SLAB_HWCACHE_ALIGN
|SLAB_PANIC
, NULL
);
1043 /* add the special key types */
1044 list_add_tail(&key_type_keyring
.link
, &key_types_list
);
1045 list_add_tail(&key_type_dead
.link
, &key_types_list
);
1046 list_add_tail(&key_type_user
.link
, &key_types_list
);
1047 list_add_tail(&key_type_logon
.link
, &key_types_list
);
1049 /* record the root user tracking */
1050 rb_link_node(&root_key_user
.node
,
1052 &key_user_tree
.rb_node
);
1054 rb_insert_color(&root_key_user
.node
,
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