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>
23 struct kmem_cache
*key_jar
;
24 struct rb_root key_serial_tree
; /* tree of keys indexed by serial */
25 DEFINE_SPINLOCK(key_serial_lock
);
27 struct rb_root key_user_tree
; /* tree of quota records indexed by UID */
28 DEFINE_SPINLOCK(key_user_lock
);
30 unsigned int key_quota_root_maxkeys
= 1000000; /* root's key count quota */
31 unsigned int key_quota_root_maxbytes
= 25000000; /* root's key space quota */
32 unsigned int key_quota_maxkeys
= 200; /* general key count quota */
33 unsigned int key_quota_maxbytes
= 20000; /* general key space quota */
35 static LIST_HEAD(key_types_list
);
36 static DECLARE_RWSEM(key_types_sem
);
38 /* We serialise key instantiation and link */
39 DEFINE_MUTEX(key_construction_mutex
);
42 void __key_check(const struct key
*key
)
44 printk("__key_check: key %p {%08x} should be {%08x}\n",
45 key
, key
->magic
, KEY_DEBUG_MAGIC
);
51 * Get the key quota record for a user, allocating a new record if one doesn't
54 struct key_user
*key_user_lookup(kuid_t uid
)
56 struct key_user
*candidate
= NULL
, *user
;
57 struct rb_node
*parent
= NULL
;
61 p
= &key_user_tree
.rb_node
;
62 spin_lock(&key_user_lock
);
64 /* search the tree for a user record with a matching UID */
67 user
= rb_entry(parent
, struct key_user
, node
);
69 if (uid_lt(uid
, user
->uid
))
71 else if (uid_gt(uid
, user
->uid
))
77 /* if we get here, we failed to find a match in the tree */
79 /* allocate a candidate user record if we don't already have
81 spin_unlock(&key_user_lock
);
84 candidate
= kmalloc(sizeof(struct key_user
), GFP_KERNEL
);
85 if (unlikely(!candidate
))
88 /* the allocation may have scheduled, so we need to repeat the
89 * search lest someone else added the record whilst we were
94 /* if we get here, then the user record still hadn't appeared on the
95 * second pass - so we use the candidate record */
96 atomic_set(&candidate
->usage
, 1);
97 atomic_set(&candidate
->nkeys
, 0);
98 atomic_set(&candidate
->nikeys
, 0);
100 candidate
->qnkeys
= 0;
101 candidate
->qnbytes
= 0;
102 spin_lock_init(&candidate
->lock
);
103 mutex_init(&candidate
->cons_lock
);
105 rb_link_node(&candidate
->node
, parent
, p
);
106 rb_insert_color(&candidate
->node
, &key_user_tree
);
107 spin_unlock(&key_user_lock
);
111 /* okay - we found a user record for this UID */
113 atomic_inc(&user
->usage
);
114 spin_unlock(&key_user_lock
);
121 * Dispose of a user structure
123 void key_user_put(struct key_user
*user
)
125 if (atomic_dec_and_lock(&user
->usage
, &key_user_lock
)) {
126 rb_erase(&user
->node
, &key_user_tree
);
127 spin_unlock(&key_user_lock
);
134 * Allocate a serial number for a key. These are assigned randomly to avoid
135 * security issues through covert channel problems.
137 static inline void key_alloc_serial(struct key
*key
)
139 struct rb_node
*parent
, **p
;
142 /* propose a random serial number and look for a hole for it in the
143 * serial number tree */
145 get_random_bytes(&key
->serial
, sizeof(key
->serial
));
147 key
->serial
>>= 1; /* negative numbers are not permitted */
148 } while (key
->serial
< 3);
150 spin_lock(&key_serial_lock
);
154 p
= &key_serial_tree
.rb_node
;
158 xkey
= rb_entry(parent
, struct key
, serial_node
);
160 if (key
->serial
< xkey
->serial
)
162 else if (key
->serial
> xkey
->serial
)
168 /* we've found a suitable hole - arrange for this key to occupy it */
169 rb_link_node(&key
->serial_node
, parent
, p
);
170 rb_insert_color(&key
->serial_node
, &key_serial_tree
);
172 spin_unlock(&key_serial_lock
);
175 /* we found a key with the proposed serial number - walk the tree from
176 * that point looking for the next unused serial number */
180 if (key
->serial
< 3) {
182 goto attempt_insertion
;
185 parent
= rb_next(parent
);
187 goto attempt_insertion
;
189 xkey
= rb_entry(parent
, struct key
, serial_node
);
190 if (key
->serial
< xkey
->serial
)
191 goto attempt_insertion
;
196 * key_alloc - Allocate a key of the specified type.
197 * @type: The type of key to allocate.
198 * @desc: The key description to allow the key to be searched out.
199 * @uid: The owner of the new key.
200 * @gid: The group ID for the new key's group permissions.
201 * @cred: The credentials specifying UID namespace.
202 * @perm: The permissions mask of the new key.
203 * @flags: Flags specifying quota properties.
205 * Allocate a key of the specified type with the attributes given. The key is
206 * returned in an uninstantiated state and the caller needs to instantiate the
207 * key before returning.
209 * The user's key count quota is updated to reflect the creation of the key and
210 * the user's key data quota has the default for the key type reserved. The
211 * instantiation function should amend this as necessary. If insufficient
212 * quota is available, -EDQUOT will be returned.
214 * The LSM security modules can prevent a key being created, in which case
215 * -EACCES will be returned.
217 * Returns a pointer to the new key if successful and an error code otherwise.
219 * Note that the caller needs to ensure the key type isn't uninstantiated.
220 * Internally this can be done by locking key_types_sem. Externally, this can
221 * be done by either never unregistering the key type, or making sure
222 * key_alloc() calls don't race with module unloading.
224 struct key
*key_alloc(struct key_type
*type
, const char *desc
,
225 kuid_t uid
, kgid_t gid
, const struct cred
*cred
,
226 key_perm_t perm
, unsigned long flags
)
228 struct key_user
*user
= NULL
;
230 size_t desclen
, quotalen
;
233 key
= ERR_PTR(-EINVAL
);
237 if (type
->vet_description
) {
238 ret
= type
->vet_description(desc
);
245 desclen
= strlen(desc
);
246 quotalen
= desclen
+ 1 + type
->def_datalen
;
248 /* get hold of the key tracking for this user */
249 user
= key_user_lookup(uid
);
253 /* check that the user's quota permits allocation of another key and
255 if (!(flags
& KEY_ALLOC_NOT_IN_QUOTA
)) {
256 unsigned maxkeys
= uid_eq(uid
, GLOBAL_ROOT_UID
) ?
257 key_quota_root_maxkeys
: key_quota_maxkeys
;
258 unsigned maxbytes
= uid_eq(uid
, GLOBAL_ROOT_UID
) ?
259 key_quota_root_maxbytes
: key_quota_maxbytes
;
261 spin_lock(&user
->lock
);
262 if (!(flags
& KEY_ALLOC_QUOTA_OVERRUN
)) {
263 if (user
->qnkeys
+ 1 >= maxkeys
||
264 user
->qnbytes
+ quotalen
>= maxbytes
||
265 user
->qnbytes
+ quotalen
< user
->qnbytes
)
270 user
->qnbytes
+= quotalen
;
271 spin_unlock(&user
->lock
);
274 /* allocate and initialise the key and its description */
275 key
= kmem_cache_zalloc(key_jar
, GFP_KERNEL
);
279 key
->index_key
.desc_len
= desclen
;
280 key
->index_key
.description
= kmemdup(desc
, desclen
+ 1, GFP_KERNEL
);
281 if (!key
->index_key
.description
)
284 atomic_set(&key
->usage
, 1);
285 init_rwsem(&key
->sem
);
286 lockdep_set_class(&key
->sem
, &type
->lock_class
);
287 key
->index_key
.type
= type
;
289 key
->quotalen
= quotalen
;
290 key
->datalen
= type
->def_datalen
;
295 if (!(flags
& KEY_ALLOC_NOT_IN_QUOTA
))
296 key
->flags
|= 1 << KEY_FLAG_IN_QUOTA
;
297 if (flags
& KEY_ALLOC_TRUSTED
)
298 key
->flags
|= 1 << KEY_FLAG_TRUSTED
;
301 key
->magic
= KEY_DEBUG_MAGIC
;
304 /* let the security module know about the key */
305 ret
= security_key_alloc(key
, cred
, flags
);
309 /* publish the key by giving it a serial number */
310 atomic_inc(&user
->nkeys
);
311 key_alloc_serial(key
);
317 kfree(key
->description
);
318 kmem_cache_free(key_jar
, key
);
319 if (!(flags
& KEY_ALLOC_NOT_IN_QUOTA
)) {
320 spin_lock(&user
->lock
);
322 user
->qnbytes
-= quotalen
;
323 spin_unlock(&user
->lock
);
330 kmem_cache_free(key_jar
, key
);
332 if (!(flags
& KEY_ALLOC_NOT_IN_QUOTA
)) {
333 spin_lock(&user
->lock
);
335 user
->qnbytes
-= quotalen
;
336 spin_unlock(&user
->lock
);
340 key
= ERR_PTR(-ENOMEM
);
344 spin_unlock(&user
->lock
);
346 key
= ERR_PTR(-EDQUOT
);
349 EXPORT_SYMBOL(key_alloc
);
352 * key_payload_reserve - Adjust data quota reservation for the key's payload
353 * @key: The key to make the reservation for.
354 * @datalen: The amount of data payload the caller now wants.
356 * Adjust the amount of the owning user's key data quota that a key reserves.
357 * If the amount is increased, then -EDQUOT may be returned if there isn't
358 * enough free quota available.
360 * If successful, 0 is returned.
362 int key_payload_reserve(struct key
*key
, size_t datalen
)
364 int delta
= (int)datalen
- key
->datalen
;
369 /* contemplate the quota adjustment */
370 if (delta
!= 0 && test_bit(KEY_FLAG_IN_QUOTA
, &key
->flags
)) {
371 unsigned maxbytes
= uid_eq(key
->user
->uid
, GLOBAL_ROOT_UID
) ?
372 key_quota_root_maxbytes
: key_quota_maxbytes
;
374 spin_lock(&key
->user
->lock
);
377 (key
->user
->qnbytes
+ delta
>= maxbytes
||
378 key
->user
->qnbytes
+ delta
< key
->user
->qnbytes
)) {
382 key
->user
->qnbytes
+= delta
;
383 key
->quotalen
+= delta
;
385 spin_unlock(&key
->user
->lock
);
388 /* change the recorded data length if that didn't generate an error */
390 key
->datalen
= datalen
;
394 EXPORT_SYMBOL(key_payload_reserve
);
397 * Instantiate a key and link it into the target keyring atomically. Must be
398 * called with the target keyring's semaphore writelocked. The target key's
399 * semaphore need not be locked as instantiation is serialised by
400 * key_construction_mutex.
402 static int __key_instantiate_and_link(struct key
*key
,
403 struct key_preparsed_payload
*prep
,
406 struct assoc_array_edit
**_edit
)
416 mutex_lock(&key_construction_mutex
);
418 /* can't instantiate twice */
419 if (!test_bit(KEY_FLAG_INSTANTIATED
, &key
->flags
)) {
420 /* instantiate the key */
421 ret
= key
->type
->instantiate(key
, prep
);
424 /* mark the key as being instantiated */
425 atomic_inc(&key
->user
->nikeys
);
426 set_bit(KEY_FLAG_INSTANTIATED
, &key
->flags
);
428 if (test_and_clear_bit(KEY_FLAG_USER_CONSTRUCT
, &key
->flags
))
431 /* and link it into the destination keyring */
433 set_bit(KEY_FLAG_KEEP
, &key
->flags
);
435 __key_link(key
, _edit
);
438 /* disable the authorisation key */
442 if (prep
->expiry
!= TIME_T_MAX
) {
443 key
->expiry
= prep
->expiry
;
444 key_schedule_gc(prep
->expiry
+ key_gc_delay
);
449 mutex_unlock(&key_construction_mutex
);
451 /* wake up anyone waiting for a key to be constructed */
453 wake_up_bit(&key
->flags
, KEY_FLAG_USER_CONSTRUCT
);
459 * key_instantiate_and_link - Instantiate a key and link it into the keyring.
460 * @key: The key to instantiate.
461 * @data: The data to use to instantiate the keyring.
462 * @datalen: The length of @data.
463 * @keyring: Keyring to create a link in on success (or NULL).
464 * @authkey: The authorisation token permitting instantiation.
466 * Instantiate a key that's in the uninstantiated state using the provided data
467 * and, if successful, link it in to the destination keyring if one is
470 * If successful, 0 is returned, the authorisation token is revoked and anyone
471 * waiting for the key is woken up. If the key was already instantiated,
472 * -EBUSY will be returned.
474 int key_instantiate_and_link(struct key
*key
,
480 struct key_preparsed_payload prep
;
481 struct assoc_array_edit
*edit
;
484 memset(&prep
, 0, sizeof(prep
));
486 prep
.datalen
= datalen
;
487 prep
.quotalen
= key
->type
->def_datalen
;
488 prep
.expiry
= TIME_T_MAX
;
489 if (key
->type
->preparse
) {
490 ret
= key
->type
->preparse(&prep
);
496 ret
= __key_link_begin(keyring
, &key
->index_key
, &edit
);
501 ret
= __key_instantiate_and_link(key
, &prep
, keyring
, authkey
, &edit
);
504 __key_link_end(keyring
, &key
->index_key
, edit
);
507 if (key
->type
->preparse
)
508 key
->type
->free_preparse(&prep
);
512 EXPORT_SYMBOL(key_instantiate_and_link
);
515 * key_reject_and_link - Negatively instantiate a key and link it into the keyring.
516 * @key: The key to instantiate.
517 * @timeout: The timeout on the negative key.
518 * @error: The error to return when the key is hit.
519 * @keyring: Keyring to create a link in on success (or NULL).
520 * @authkey: The authorisation token permitting instantiation.
522 * Negatively instantiate a key that's in the uninstantiated state and, if
523 * successful, set its timeout and stored error and link it in to the
524 * destination keyring if one is supplied. The key and any links to the key
525 * will be automatically garbage collected after the timeout expires.
527 * Negative keys are used to rate limit repeated request_key() calls by causing
528 * them to return the stored error code (typically ENOKEY) until the negative
531 * If successful, 0 is returned, the authorisation token is revoked and anyone
532 * waiting for the key is woken up. If the key was already instantiated,
533 * -EBUSY will be returned.
535 int key_reject_and_link(struct key
*key
,
541 struct assoc_array_edit
*edit
;
543 int ret
, awaken
, link_ret
= 0;
552 link_ret
= __key_link_begin(keyring
, &key
->index_key
, &edit
);
554 mutex_lock(&key_construction_mutex
);
556 /* can't instantiate twice */
557 if (!test_bit(KEY_FLAG_INSTANTIATED
, &key
->flags
)) {
558 /* mark the key as being negatively instantiated */
559 atomic_inc(&key
->user
->nikeys
);
560 key
->reject_error
= -error
;
562 set_bit(KEY_FLAG_NEGATIVE
, &key
->flags
);
563 set_bit(KEY_FLAG_INSTANTIATED
, &key
->flags
);
564 now
= current_kernel_time();
565 key
->expiry
= now
.tv_sec
+ timeout
;
566 key_schedule_gc(key
->expiry
+ key_gc_delay
);
568 if (test_and_clear_bit(KEY_FLAG_USER_CONSTRUCT
, &key
->flags
))
573 /* and link it into the destination keyring */
574 if (keyring
&& link_ret
== 0)
575 __key_link(key
, &edit
);
577 /* disable the authorisation key */
582 mutex_unlock(&key_construction_mutex
);
585 __key_link_end(keyring
, &key
->index_key
, edit
);
587 /* wake up anyone waiting for a key to be constructed */
589 wake_up_bit(&key
->flags
, KEY_FLAG_USER_CONSTRUCT
);
591 return ret
== 0 ? link_ret
: ret
;
593 EXPORT_SYMBOL(key_reject_and_link
);
596 * key_put - Discard a reference to a key.
597 * @key: The key to discard a reference from.
599 * Discard a reference to a key, and when all the references are gone, we
600 * schedule the cleanup task to come and pull it out of the tree in process
601 * context at some later time.
603 void key_put(struct key
*key
)
608 if (atomic_dec_and_test(&key
->usage
))
609 schedule_work(&key_gc_work
);
612 EXPORT_SYMBOL(key_put
);
615 * Find a key by its serial number.
617 struct key
*key_lookup(key_serial_t id
)
622 spin_lock(&key_serial_lock
);
624 /* search the tree for the specified key */
625 n
= key_serial_tree
.rb_node
;
627 key
= rb_entry(n
, struct key
, serial_node
);
629 if (id
< key
->serial
)
631 else if (id
> key
->serial
)
638 key
= ERR_PTR(-ENOKEY
);
642 /* pretend it doesn't exist if it is awaiting deletion */
643 if (atomic_read(&key
->usage
) == 0)
646 /* this races with key_put(), but that doesn't matter since key_put()
647 * doesn't actually change the key
652 spin_unlock(&key_serial_lock
);
657 * Find and lock the specified key type against removal.
659 * We return with the sem read-locked if successful. If the type wasn't
660 * available -ENOKEY is returned instead.
662 struct key_type
*key_type_lookup(const char *type
)
664 struct key_type
*ktype
;
666 down_read(&key_types_sem
);
668 /* look up the key type to see if it's one of the registered kernel
670 list_for_each_entry(ktype
, &key_types_list
, link
) {
671 if (strcmp(ktype
->name
, type
) == 0)
672 goto found_kernel_type
;
675 up_read(&key_types_sem
);
676 ktype
= ERR_PTR(-ENOKEY
);
682 void key_set_timeout(struct key
*key
, unsigned timeout
)
687 /* make the changes with the locks held to prevent races */
688 down_write(&key
->sem
);
691 now
= current_kernel_time();
692 expiry
= now
.tv_sec
+ timeout
;
695 key
->expiry
= expiry
;
696 key_schedule_gc(key
->expiry
+ key_gc_delay
);
700 EXPORT_SYMBOL_GPL(key_set_timeout
);
703 * Unlock a key type locked by key_type_lookup().
705 void key_type_put(struct key_type
*ktype
)
707 up_read(&key_types_sem
);
711 * Attempt to update an existing key.
713 * The key is given to us with an incremented refcount that we need to discard
714 * if we get an error.
716 static inline key_ref_t
__key_update(key_ref_t key_ref
,
717 struct key_preparsed_payload
*prep
)
719 struct key
*key
= key_ref_to_ptr(key_ref
);
722 /* need write permission on the key to update it */
723 ret
= key_permission(key_ref
, KEY_NEED_WRITE
);
728 if (!key
->type
->update
)
731 down_write(&key
->sem
);
733 ret
= key
->type
->update(key
, prep
);
735 /* updating a negative key instantiates it */
736 clear_bit(KEY_FLAG_NEGATIVE
, &key
->flags
);
747 key_ref
= ERR_PTR(ret
);
752 * key_create_or_update - Update or create and instantiate a key.
753 * @keyring_ref: A pointer to the destination keyring with possession flag.
754 * @type: The type of key.
755 * @description: The searchable description for the key.
756 * @payload: The data to use to instantiate or update the key.
757 * @plen: The length of @payload.
758 * @perm: The permissions mask for a new key.
759 * @flags: The quota flags for a new key.
761 * Search the destination keyring for a key of the same description and if one
762 * is found, update it, otherwise create and instantiate a new one and create a
763 * link to it from that keyring.
765 * If perm is KEY_PERM_UNDEF then an appropriate key permissions mask will be
768 * Returns a pointer to the new key if successful, -ENODEV if the key type
769 * wasn't available, -ENOTDIR if the keyring wasn't a keyring, -EACCES if the
770 * caller isn't permitted to modify the keyring or the LSM did not permit
771 * creation of the key.
773 * On success, the possession flag from the keyring ref will be tacked on to
774 * the key ref before it is returned.
776 key_ref_t
key_create_or_update(key_ref_t keyring_ref
,
778 const char *description
,
784 struct keyring_index_key index_key
= {
785 .description
= description
,
787 struct key_preparsed_payload prep
;
788 struct assoc_array_edit
*edit
;
789 const struct cred
*cred
= current_cred();
790 struct key
*keyring
, *key
= NULL
;
794 /* look up the key type to see if it's one of the registered kernel
796 index_key
.type
= key_type_lookup(type
);
797 if (IS_ERR(index_key
.type
)) {
798 key_ref
= ERR_PTR(-ENODEV
);
802 key_ref
= ERR_PTR(-EINVAL
);
803 if (!index_key
.type
->instantiate
||
804 (!index_key
.description
&& !index_key
.type
->preparse
))
807 keyring
= key_ref_to_ptr(keyring_ref
);
811 key_ref
= ERR_PTR(-ENOTDIR
);
812 if (keyring
->type
!= &key_type_keyring
)
815 memset(&prep
, 0, sizeof(prep
));
818 prep
.quotalen
= index_key
.type
->def_datalen
;
819 prep
.trusted
= flags
& KEY_ALLOC_TRUSTED
;
820 prep
.expiry
= TIME_T_MAX
;
821 if (index_key
.type
->preparse
) {
822 ret
= index_key
.type
->preparse(&prep
);
824 key_ref
= ERR_PTR(ret
);
825 goto error_free_prep
;
827 if (!index_key
.description
)
828 index_key
.description
= prep
.description
;
829 key_ref
= ERR_PTR(-EINVAL
);
830 if (!index_key
.description
)
831 goto error_free_prep
;
833 index_key
.desc_len
= strlen(index_key
.description
);
835 key_ref
= ERR_PTR(-EPERM
);
836 if (!prep
.trusted
&& test_bit(KEY_FLAG_TRUSTED_ONLY
, &keyring
->flags
))
837 goto error_free_prep
;
838 flags
|= prep
.trusted
? KEY_ALLOC_TRUSTED
: 0;
840 ret
= __key_link_begin(keyring
, &index_key
, &edit
);
842 key_ref
= ERR_PTR(ret
);
843 goto error_free_prep
;
846 /* if we're going to allocate a new key, we're going to have
847 * to modify the keyring */
848 ret
= key_permission(keyring_ref
, KEY_NEED_WRITE
);
850 key_ref
= ERR_PTR(ret
);
854 /* if it's possible to update this type of key, search for an existing
855 * key of the same type and description in the destination keyring and
856 * update that instead if possible
858 if (index_key
.type
->update
) {
859 key_ref
= find_key_to_update(keyring_ref
, &index_key
);
861 goto found_matching_key
;
864 /* if the client doesn't provide, decide on the permissions we want */
865 if (perm
== KEY_PERM_UNDEF
) {
866 perm
= KEY_POS_VIEW
| KEY_POS_SEARCH
| KEY_POS_LINK
| KEY_POS_SETATTR
;
867 perm
|= KEY_USR_VIEW
;
869 if (index_key
.type
->read
)
870 perm
|= KEY_POS_READ
;
872 if (index_key
.type
== &key_type_keyring
||
873 index_key
.type
->update
)
874 perm
|= KEY_POS_WRITE
;
877 /* allocate a new key */
878 key
= key_alloc(index_key
.type
, index_key
.description
,
879 cred
->fsuid
, cred
->fsgid
, cred
, perm
, flags
);
881 key_ref
= ERR_CAST(key
);
885 /* instantiate it and link it into the target keyring */
886 ret
= __key_instantiate_and_link(key
, &prep
, keyring
, NULL
, &edit
);
889 key_ref
= ERR_PTR(ret
);
893 key_ref
= make_key_ref(key
, is_key_possessed(keyring_ref
));
896 __key_link_end(keyring
, &index_key
, edit
);
898 if (index_key
.type
->preparse
)
899 index_key
.type
->free_preparse(&prep
);
901 key_type_put(index_key
.type
);
906 /* we found a matching key, so we're going to try to update it
907 * - we can drop the locks first as we have the key pinned
909 __key_link_end(keyring
, &index_key
, edit
);
911 key_ref
= __key_update(key_ref
, &prep
);
912 goto error_free_prep
;
914 EXPORT_SYMBOL(key_create_or_update
);
917 * key_update - Update a key's contents.
918 * @key_ref: The pointer (plus possession flag) to the key.
919 * @payload: The data to be used to update the key.
920 * @plen: The length of @payload.
922 * Attempt to update the contents of a key with the given payload data. The
923 * caller must be granted Write permission on the key. Negative keys can be
924 * instantiated by this method.
926 * Returns 0 on success, -EACCES if not permitted and -EOPNOTSUPP if the key
927 * type does not support updating. The key type may return other errors.
929 int key_update(key_ref_t key_ref
, const void *payload
, size_t plen
)
931 struct key_preparsed_payload prep
;
932 struct key
*key
= key_ref_to_ptr(key_ref
);
937 /* the key must be writable */
938 ret
= key_permission(key_ref
, KEY_NEED_WRITE
);
942 /* attempt to update it if supported */
944 if (!key
->type
->update
)
947 memset(&prep
, 0, sizeof(prep
));
950 prep
.quotalen
= key
->type
->def_datalen
;
951 prep
.expiry
= TIME_T_MAX
;
952 if (key
->type
->preparse
) {
953 ret
= key
->type
->preparse(&prep
);
958 down_write(&key
->sem
);
960 ret
= key
->type
->update(key
, &prep
);
962 /* updating a negative key instantiates it */
963 clear_bit(KEY_FLAG_NEGATIVE
, &key
->flags
);
968 if (key
->type
->preparse
)
969 key
->type
->free_preparse(&prep
);
972 EXPORT_SYMBOL(key_update
);
975 * key_revoke - Revoke a key.
976 * @key: The key to be revoked.
978 * Mark a key as being revoked and ask the type to free up its resources. The
979 * revocation timeout is set and the key and all its links will be
980 * automatically garbage collected after key_gc_delay amount of time if they
981 * are not manually dealt with first.
983 void key_revoke(struct key
*key
)
990 /* make sure no one's trying to change or use the key when we mark it
991 * - we tell lockdep that we might nest because we might be revoking an
992 * authorisation key whilst holding the sem on a key we've just
995 down_write_nested(&key
->sem
, 1);
996 if (!test_and_set_bit(KEY_FLAG_REVOKED
, &key
->flags
) &&
998 key
->type
->revoke(key
);
1000 /* set the death time to no more than the expiry time */
1001 now
= current_kernel_time();
1003 if (key
->revoked_at
== 0 || key
->revoked_at
> time
) {
1004 key
->revoked_at
= time
;
1005 key_schedule_gc(key
->revoked_at
+ key_gc_delay
);
1008 up_write(&key
->sem
);
1010 EXPORT_SYMBOL(key_revoke
);
1013 * key_invalidate - Invalidate a key.
1014 * @key: The key to be invalidated.
1016 * Mark a key as being invalidated and have it cleaned up immediately. The key
1017 * is ignored by all searches and other operations from this point.
1019 void key_invalidate(struct key
*key
)
1021 kenter("%d", key_serial(key
));
1025 if (!test_bit(KEY_FLAG_INVALIDATED
, &key
->flags
)) {
1026 down_write_nested(&key
->sem
, 1);
1027 if (!test_and_set_bit(KEY_FLAG_INVALIDATED
, &key
->flags
))
1028 key_schedule_gc_links();
1029 up_write(&key
->sem
);
1032 EXPORT_SYMBOL(key_invalidate
);
1035 * generic_key_instantiate - Simple instantiation of a key from preparsed data
1036 * @key: The key to be instantiated
1037 * @prep: The preparsed data to load.
1039 * Instantiate a key from preparsed data. We assume we can just copy the data
1040 * in directly and clear the old pointers.
1042 * This can be pointed to directly by the key type instantiate op pointer.
1044 int generic_key_instantiate(struct key
*key
, struct key_preparsed_payload
*prep
)
1048 pr_devel("==>%s()\n", __func__
);
1050 ret
= key_payload_reserve(key
, prep
->quotalen
);
1052 rcu_assign_keypointer(key
, prep
->payload
.data
[0]);
1053 key
->payload
.data
[1] = prep
->payload
.data
[1];
1054 key
->payload
.data
[2] = prep
->payload
.data
[2];
1055 key
->payload
.data
[3] = prep
->payload
.data
[3];
1056 prep
->payload
.data
[0] = NULL
;
1057 prep
->payload
.data
[1] = NULL
;
1058 prep
->payload
.data
[2] = NULL
;
1059 prep
->payload
.data
[3] = NULL
;
1061 pr_devel("<==%s() = %d\n", __func__
, ret
);
1064 EXPORT_SYMBOL(generic_key_instantiate
);
1067 * register_key_type - Register a type of key.
1068 * @ktype: The new key type.
1070 * Register a new key type.
1072 * Returns 0 on success or -EEXIST if a type of this name already exists.
1074 int register_key_type(struct key_type
*ktype
)
1079 memset(&ktype
->lock_class
, 0, sizeof(ktype
->lock_class
));
1082 down_write(&key_types_sem
);
1084 /* disallow key types with the same name */
1085 list_for_each_entry(p
, &key_types_list
, link
) {
1086 if (strcmp(p
->name
, ktype
->name
) == 0)
1090 /* store the type */
1091 list_add(&ktype
->link
, &key_types_list
);
1093 pr_notice("Key type %s registered\n", ktype
->name
);
1097 up_write(&key_types_sem
);
1100 EXPORT_SYMBOL(register_key_type
);
1103 * unregister_key_type - Unregister a type of key.
1104 * @ktype: The key type.
1106 * Unregister a key type and mark all the extant keys of this type as dead.
1107 * Those keys of this type are then destroyed to get rid of their payloads and
1108 * they and their links will be garbage collected as soon as possible.
1110 void unregister_key_type(struct key_type
*ktype
)
1112 down_write(&key_types_sem
);
1113 list_del_init(&ktype
->link
);
1114 downgrade_write(&key_types_sem
);
1115 key_gc_keytype(ktype
);
1116 pr_notice("Key type %s unregistered\n", ktype
->name
);
1117 up_read(&key_types_sem
);
1119 EXPORT_SYMBOL(unregister_key_type
);
1122 * Initialise the key management state.
1124 void __init
key_init(void)
1126 /* allocate a slab in which we can store keys */
1127 key_jar
= kmem_cache_create("key_jar", sizeof(struct key
),
1128 0, SLAB_HWCACHE_ALIGN
|SLAB_PANIC
, NULL
);
1130 /* add the special key types */
1131 list_add_tail(&key_type_keyring
.link
, &key_types_list
);
1132 list_add_tail(&key_type_dead
.link
, &key_types_list
);
1133 list_add_tail(&key_type_user
.link
, &key_types_list
);
1134 list_add_tail(&key_type_logon
.link
, &key_types_list
);
1136 /* record the root user tracking */
1137 rb_link_node(&root_key_user
.node
,
1139 &key_user_tree
.rb_node
);
1141 rb_insert_color(&root_key_user
.node
,