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
,
415 struct key_preparsed_payload
*prep
,
418 unsigned long *_prealloc
)
428 mutex_lock(&key_construction_mutex
);
430 /* can't instantiate twice */
431 if (!test_bit(KEY_FLAG_INSTANTIATED
, &key
->flags
)) {
432 /* instantiate the key */
433 ret
= key
->type
->instantiate(key
, prep
);
436 /* mark the key as being instantiated */
437 atomic_inc(&key
->user
->nikeys
);
438 set_bit(KEY_FLAG_INSTANTIATED
, &key
->flags
);
440 if (test_and_clear_bit(KEY_FLAG_USER_CONSTRUCT
, &key
->flags
))
443 /* and link it into the destination keyring */
445 __key_link(keyring
, key
, _prealloc
);
447 /* disable the authorisation key */
453 mutex_unlock(&key_construction_mutex
);
455 /* wake up anyone waiting for a key to be constructed */
457 wake_up_bit(&key
->flags
, KEY_FLAG_USER_CONSTRUCT
);
463 * key_instantiate_and_link - Instantiate a key and link it into the keyring.
464 * @key: The key to instantiate.
465 * @data: The data to use to instantiate the keyring.
466 * @datalen: The length of @data.
467 * @keyring: Keyring to create a link in on success (or NULL).
468 * @authkey: The authorisation token permitting instantiation.
470 * Instantiate a key that's in the uninstantiated state using the provided data
471 * and, if successful, link it in to the destination keyring if one is
474 * If successful, 0 is returned, the authorisation token is revoked and anyone
475 * waiting for the key is woken up. If the key was already instantiated,
476 * -EBUSY will be returned.
478 int key_instantiate_and_link(struct key
*key
,
484 struct key_preparsed_payload prep
;
485 unsigned long prealloc
;
488 memset(&prep
, 0, sizeof(prep
));
490 prep
.datalen
= datalen
;
491 prep
.quotalen
= key
->type
->def_datalen
;
492 if (key
->type
->preparse
) {
493 ret
= key
->type
->preparse(&prep
);
499 ret
= __key_link_begin(keyring
, key
->type
, key
->description
,
502 goto error_free_preparse
;
505 ret
= __key_instantiate_and_link(key
, &prep
, keyring
, authkey
,
509 __key_link_end(keyring
, key
->type
, prealloc
);
512 if (key
->type
->preparse
)
513 key
->type
->free_preparse(&prep
);
518 EXPORT_SYMBOL(key_instantiate_and_link
);
521 * key_reject_and_link - Negatively instantiate a key and link it into the keyring.
522 * @key: The key to instantiate.
523 * @timeout: The timeout on the negative key.
524 * @error: The error to return when the key is hit.
525 * @keyring: Keyring to create a link in on success (or NULL).
526 * @authkey: The authorisation token permitting instantiation.
528 * Negatively instantiate a key that's in the uninstantiated state and, if
529 * successful, set its timeout and stored error and link it in to the
530 * destination keyring if one is supplied. The key and any links to the key
531 * will be automatically garbage collected after the timeout expires.
533 * Negative keys are used to rate limit repeated request_key() calls by causing
534 * them to return the stored error code (typically ENOKEY) until the negative
537 * If successful, 0 is returned, the authorisation token is revoked and anyone
538 * waiting for the key is woken up. If the key was already instantiated,
539 * -EBUSY will be returned.
541 int key_reject_and_link(struct key
*key
,
547 unsigned long prealloc
;
549 int ret
, awaken
, link_ret
= 0;
558 link_ret
= __key_link_begin(keyring
, key
->type
,
559 key
->description
, &prealloc
);
561 mutex_lock(&key_construction_mutex
);
563 /* can't instantiate twice */
564 if (!test_bit(KEY_FLAG_INSTANTIATED
, &key
->flags
)) {
565 /* mark the key as being negatively instantiated */
566 atomic_inc(&key
->user
->nikeys
);
567 set_bit(KEY_FLAG_NEGATIVE
, &key
->flags
);
568 set_bit(KEY_FLAG_INSTANTIATED
, &key
->flags
);
569 key
->type_data
.reject_error
= -error
;
570 now
= current_kernel_time();
571 key
->expiry
= now
.tv_sec
+ timeout
;
572 key_schedule_gc(key
->expiry
+ key_gc_delay
);
574 if (test_and_clear_bit(KEY_FLAG_USER_CONSTRUCT
, &key
->flags
))
579 /* and link it into the destination keyring */
580 if (keyring
&& link_ret
== 0)
581 __key_link(keyring
, key
, &prealloc
);
583 /* disable the authorisation key */
588 mutex_unlock(&key_construction_mutex
);
591 __key_link_end(keyring
, key
->type
, prealloc
);
593 /* wake up anyone waiting for a key to be constructed */
595 wake_up_bit(&key
->flags
, KEY_FLAG_USER_CONSTRUCT
);
597 return ret
== 0 ? link_ret
: ret
;
599 EXPORT_SYMBOL(key_reject_and_link
);
602 * key_put - Discard a reference to a key.
603 * @key: The key to discard a reference from.
605 * Discard a reference to a key, and when all the references are gone, we
606 * schedule the cleanup task to come and pull it out of the tree in process
607 * context at some later time.
609 void key_put(struct key
*key
)
614 if (atomic_dec_and_test(&key
->usage
))
615 queue_work(system_nrt_wq
, &key_gc_work
);
618 EXPORT_SYMBOL(key_put
);
621 * Find a key by its serial number.
623 struct key
*key_lookup(key_serial_t id
)
628 spin_lock(&key_serial_lock
);
630 /* search the tree for the specified key */
631 n
= key_serial_tree
.rb_node
;
633 key
= rb_entry(n
, struct key
, serial_node
);
635 if (id
< key
->serial
)
637 else if (id
> key
->serial
)
644 key
= ERR_PTR(-ENOKEY
);
648 /* pretend it doesn't exist if it is awaiting deletion */
649 if (atomic_read(&key
->usage
) == 0)
652 /* this races with key_put(), but that doesn't matter since key_put()
653 * doesn't actually change the key
655 atomic_inc(&key
->usage
);
658 spin_unlock(&key_serial_lock
);
663 * Find and lock the specified key type against removal.
665 * We return with the sem read-locked if successful. If the type wasn't
666 * available -ENOKEY is returned instead.
668 struct key_type
*key_type_lookup(const char *type
)
670 struct key_type
*ktype
;
672 down_read(&key_types_sem
);
674 /* look up the key type to see if it's one of the registered kernel
676 list_for_each_entry(ktype
, &key_types_list
, link
) {
677 if (strcmp(ktype
->name
, type
) == 0)
678 goto found_kernel_type
;
681 up_read(&key_types_sem
);
682 ktype
= ERR_PTR(-ENOKEY
);
688 void key_set_timeout(struct key
*key
, unsigned timeout
)
693 /* make the changes with the locks held to prevent races */
694 down_write(&key
->sem
);
697 now
= current_kernel_time();
698 expiry
= now
.tv_sec
+ timeout
;
701 key
->expiry
= expiry
;
702 key_schedule_gc(key
->expiry
+ key_gc_delay
);
706 EXPORT_SYMBOL_GPL(key_set_timeout
);
709 * Unlock a key type locked by key_type_lookup().
711 void key_type_put(struct key_type
*ktype
)
713 up_read(&key_types_sem
);
717 * Attempt to update an existing key.
719 * The key is given to us with an incremented refcount that we need to discard
720 * if we get an error.
722 static inline key_ref_t
__key_update(key_ref_t key_ref
,
723 struct key_preparsed_payload
*prep
)
725 struct key
*key
= key_ref_to_ptr(key_ref
);
728 /* need write permission on the key to update it */
729 ret
= key_permission(key_ref
, KEY_WRITE
);
734 if (!key
->type
->update
)
737 down_write(&key
->sem
);
739 ret
= key
->type
->update(key
, prep
);
741 /* updating a negative key instantiates it */
742 clear_bit(KEY_FLAG_NEGATIVE
, &key
->flags
);
753 key_ref
= ERR_PTR(ret
);
758 * key_create_or_update - Update or create and instantiate a key.
759 * @keyring_ref: A pointer to the destination keyring with possession flag.
760 * @type: The type of key.
761 * @description: The searchable description for the key.
762 * @payload: The data to use to instantiate or update the key.
763 * @plen: The length of @payload.
764 * @perm: The permissions mask for a new key.
765 * @flags: The quota flags for a new key.
767 * Search the destination keyring for a key of the same description and if one
768 * is found, update it, otherwise create and instantiate a new one and create a
769 * link to it from that keyring.
771 * If perm is KEY_PERM_UNDEF then an appropriate key permissions mask will be
774 * Returns a pointer to the new key if successful, -ENODEV if the key type
775 * wasn't available, -ENOTDIR if the keyring wasn't a keyring, -EACCES if the
776 * caller isn't permitted to modify the keyring or the LSM did not permit
777 * creation of the key.
779 * On success, the possession flag from the keyring ref will be tacked on to
780 * the key ref before it is returned.
782 key_ref_t
key_create_or_update(key_ref_t keyring_ref
,
784 const char *description
,
790 unsigned long prealloc
;
791 struct key_preparsed_payload prep
;
792 const struct cred
*cred
= current_cred();
793 struct key_type
*ktype
;
794 struct key
*keyring
, *key
= NULL
;
798 /* look up the key type to see if it's one of the registered kernel
800 ktype
= key_type_lookup(type
);
802 key_ref
= ERR_PTR(-ENODEV
);
806 key_ref
= ERR_PTR(-EINVAL
);
807 if (!ktype
->match
|| !ktype
->instantiate
||
808 (!description
&& !ktype
->preparse
))
811 keyring
= key_ref_to_ptr(keyring_ref
);
815 key_ref
= ERR_PTR(-ENOTDIR
);
816 if (keyring
->type
!= &key_type_keyring
)
819 memset(&prep
, 0, sizeof(prep
));
822 prep
.quotalen
= ktype
->def_datalen
;
823 if (ktype
->preparse
) {
824 ret
= ktype
->preparse(&prep
);
826 key_ref
= ERR_PTR(ret
);
830 description
= prep
.description
;
831 key_ref
= ERR_PTR(-EINVAL
);
833 goto error_free_prep
;
836 ret
= __key_link_begin(keyring
, ktype
, description
, &prealloc
);
838 key_ref
= ERR_PTR(ret
);
839 goto error_free_prep
;
842 /* if we're going to allocate a new key, we're going to have
843 * to modify the keyring */
844 ret
= key_permission(keyring_ref
, KEY_WRITE
);
846 key_ref
= ERR_PTR(ret
);
850 /* if it's possible to update this type of key, search for an existing
851 * key of the same type and description in the destination keyring and
852 * update that instead if possible
855 key_ref
= __keyring_search_one(keyring_ref
, ktype
, description
,
857 if (!IS_ERR(key_ref
))
858 goto found_matching_key
;
861 /* if the client doesn't provide, decide on the permissions we want */
862 if (perm
== KEY_PERM_UNDEF
) {
863 perm
= KEY_POS_VIEW
| KEY_POS_SEARCH
| KEY_POS_LINK
| KEY_POS_SETATTR
;
864 perm
|= KEY_USR_VIEW
| KEY_USR_SEARCH
| KEY_USR_LINK
| KEY_USR_SETATTR
;
867 perm
|= KEY_POS_READ
| KEY_USR_READ
;
869 if (ktype
== &key_type_keyring
|| ktype
->update
)
870 perm
|= KEY_USR_WRITE
;
873 /* allocate a new key */
874 key
= key_alloc(ktype
, description
, cred
->fsuid
, cred
->fsgid
, cred
,
877 key_ref
= ERR_CAST(key
);
881 /* instantiate it and link it into the target keyring */
882 ret
= __key_instantiate_and_link(key
, &prep
, keyring
, NULL
, &prealloc
);
885 key_ref
= ERR_PTR(ret
);
889 key_ref
= make_key_ref(key
, is_key_possessed(keyring_ref
));
892 __key_link_end(keyring
, ktype
, prealloc
);
895 ktype
->free_preparse(&prep
);
902 /* we found a matching key, so we're going to try to update it
903 * - we can drop the locks first as we have the key pinned
905 __key_link_end(keyring
, ktype
, prealloc
);
907 key_ref
= __key_update(key_ref
, &prep
);
908 goto error_free_prep
;
910 EXPORT_SYMBOL(key_create_or_update
);
913 * key_update - Update a key's contents.
914 * @key_ref: The pointer (plus possession flag) to the key.
915 * @payload: The data to be used to update the key.
916 * @plen: The length of @payload.
918 * Attempt to update the contents of a key with the given payload data. The
919 * caller must be granted Write permission on the key. Negative keys can be
920 * instantiated by this method.
922 * Returns 0 on success, -EACCES if not permitted and -EOPNOTSUPP if the key
923 * type does not support updating. The key type may return other errors.
925 int key_update(key_ref_t key_ref
, const void *payload
, size_t plen
)
927 struct key_preparsed_payload prep
;
928 struct key
*key
= key_ref_to_ptr(key_ref
);
933 /* the key must be writable */
934 ret
= key_permission(key_ref
, KEY_WRITE
);
938 /* attempt to update it if supported */
940 if (!key
->type
->update
)
943 memset(&prep
, 0, sizeof(prep
));
946 prep
.quotalen
= key
->type
->def_datalen
;
947 if (key
->type
->preparse
) {
948 ret
= key
->type
->preparse(&prep
);
953 down_write(&key
->sem
);
955 ret
= key
->type
->update(key
, &prep
);
957 /* updating a negative key instantiates it */
958 clear_bit(KEY_FLAG_NEGATIVE
, &key
->flags
);
962 if (key
->type
->preparse
)
963 key
->type
->free_preparse(&prep
);
967 EXPORT_SYMBOL(key_update
);
970 * key_revoke - Revoke a key.
971 * @key: The key to be revoked.
973 * Mark a key as being revoked and ask the type to free up its resources. The
974 * revocation timeout is set and the key and all its links will be
975 * automatically garbage collected after key_gc_delay amount of time if they
976 * are not manually dealt with first.
978 void key_revoke(struct key
*key
)
985 /* make sure no one's trying to change or use the key when we mark it
986 * - we tell lockdep that we might nest because we might be revoking an
987 * authorisation key whilst holding the sem on a key we've just
990 down_write_nested(&key
->sem
, 1);
991 if (!test_and_set_bit(KEY_FLAG_REVOKED
, &key
->flags
) &&
993 key
->type
->revoke(key
);
995 /* set the death time to no more than the expiry time */
996 now
= current_kernel_time();
998 if (key
->revoked_at
== 0 || key
->revoked_at
> time
) {
999 key
->revoked_at
= time
;
1000 key_schedule_gc(key
->revoked_at
+ key_gc_delay
);
1003 up_write(&key
->sem
);
1005 EXPORT_SYMBOL(key_revoke
);
1008 * key_invalidate - Invalidate a key.
1009 * @key: The key to be invalidated.
1011 * Mark a key as being invalidated and have it cleaned up immediately. The key
1012 * is ignored by all searches and other operations from this point.
1014 void key_invalidate(struct key
*key
)
1016 kenter("%d", key_serial(key
));
1020 if (!test_bit(KEY_FLAG_INVALIDATED
, &key
->flags
)) {
1021 down_write_nested(&key
->sem
, 1);
1022 if (!test_and_set_bit(KEY_FLAG_INVALIDATED
, &key
->flags
))
1023 key_schedule_gc_links();
1024 up_write(&key
->sem
);
1027 EXPORT_SYMBOL(key_invalidate
);
1030 * register_key_type - Register a type of key.
1031 * @ktype: The new key type.
1033 * Register a new key type.
1035 * Returns 0 on success or -EEXIST if a type of this name already exists.
1037 int register_key_type(struct key_type
*ktype
)
1042 memset(&ktype
->lock_class
, 0, sizeof(ktype
->lock_class
));
1045 down_write(&key_types_sem
);
1047 /* disallow key types with the same name */
1048 list_for_each_entry(p
, &key_types_list
, link
) {
1049 if (strcmp(p
->name
, ktype
->name
) == 0)
1053 /* store the type */
1054 list_add(&ktype
->link
, &key_types_list
);
1056 pr_notice("Key type %s registered\n", ktype
->name
);
1060 up_write(&key_types_sem
);
1063 EXPORT_SYMBOL(register_key_type
);
1066 * unregister_key_type - Unregister a type of key.
1067 * @ktype: The key type.
1069 * Unregister a key type and mark all the extant keys of this type as dead.
1070 * Those keys of this type are then destroyed to get rid of their payloads and
1071 * they and their links will be garbage collected as soon as possible.
1073 void unregister_key_type(struct key_type
*ktype
)
1075 down_write(&key_types_sem
);
1076 list_del_init(&ktype
->link
);
1077 downgrade_write(&key_types_sem
);
1078 key_gc_keytype(ktype
);
1079 pr_notice("Key type %s unregistered\n", ktype
->name
);
1080 up_read(&key_types_sem
);
1082 EXPORT_SYMBOL(unregister_key_type
);
1085 * Initialise the key management state.
1087 void __init
key_init(void)
1089 /* allocate a slab in which we can store keys */
1090 key_jar
= kmem_cache_create("key_jar", sizeof(struct key
),
1091 0, SLAB_HWCACHE_ALIGN
|SLAB_PANIC
, NULL
);
1093 /* add the special key types */
1094 list_add_tail(&key_type_keyring
.link
, &key_types_list
);
1095 list_add_tail(&key_type_dead
.link
, &key_types_list
);
1096 list_add_tail(&key_type_user
.link
, &key_types_list
);
1097 list_add_tail(&key_type_logon
.link
, &key_types_list
);
1099 /* record the root user tracking */
1100 rb_link_node(&root_key_user
.node
,
1102 &key_user_tree
.rb_node
);
1104 rb_insert_color(&root_key_user
.node
,