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/export.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
, **p
;
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 refcount_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 refcount_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 (refcount_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.
204 * @restrict_link: Optional link restriction for new keyrings.
206 * Allocate a key of the specified type with the attributes given. The key is
207 * returned in an uninstantiated state and the caller needs to instantiate the
208 * key before returning.
210 * The restrict_link structure (if not NULL) will be freed when the
211 * keyring is destroyed, so it must be dynamically allocated.
213 * The user's key count quota is updated to reflect the creation of the key and
214 * the user's key data quota has the default for the key type reserved. The
215 * instantiation function should amend this as necessary. If insufficient
216 * quota is available, -EDQUOT will be returned.
218 * The LSM security modules can prevent a key being created, in which case
219 * -EACCES will be returned.
221 * Returns a pointer to the new key if successful and an error code otherwise.
223 * Note that the caller needs to ensure the key type isn't uninstantiated.
224 * Internally this can be done by locking key_types_sem. Externally, this can
225 * be done by either never unregistering the key type, or making sure
226 * key_alloc() calls don't race with module unloading.
228 struct key
*key_alloc(struct key_type
*type
, const char *desc
,
229 kuid_t uid
, kgid_t gid
, const struct cred
*cred
,
230 key_perm_t perm
, unsigned long flags
,
231 struct key_restriction
*restrict_link
)
233 struct key_user
*user
= NULL
;
235 size_t desclen
, quotalen
;
238 key
= ERR_PTR(-EINVAL
);
242 if (type
->vet_description
) {
243 ret
= type
->vet_description(desc
);
250 desclen
= strlen(desc
);
251 quotalen
= desclen
+ 1 + type
->def_datalen
;
253 /* get hold of the key tracking for this user */
254 user
= key_user_lookup(uid
);
258 /* check that the user's quota permits allocation of another key and
260 if (!(flags
& KEY_ALLOC_NOT_IN_QUOTA
)) {
261 unsigned maxkeys
= uid_eq(uid
, GLOBAL_ROOT_UID
) ?
262 key_quota_root_maxkeys
: key_quota_maxkeys
;
263 unsigned maxbytes
= uid_eq(uid
, GLOBAL_ROOT_UID
) ?
264 key_quota_root_maxbytes
: key_quota_maxbytes
;
266 spin_lock(&user
->lock
);
267 if (!(flags
& KEY_ALLOC_QUOTA_OVERRUN
)) {
268 if (user
->qnkeys
+ 1 > maxkeys
||
269 user
->qnbytes
+ quotalen
> maxbytes
||
270 user
->qnbytes
+ quotalen
< user
->qnbytes
)
275 user
->qnbytes
+= quotalen
;
276 spin_unlock(&user
->lock
);
279 /* allocate and initialise the key and its description */
280 key
= kmem_cache_zalloc(key_jar
, GFP_KERNEL
);
284 key
->index_key
.desc_len
= desclen
;
285 key
->index_key
.description
= kmemdup(desc
, desclen
+ 1, GFP_KERNEL
);
286 if (!key
->index_key
.description
)
289 refcount_set(&key
->usage
, 1);
290 init_rwsem(&key
->sem
);
291 lockdep_set_class(&key
->sem
, &type
->lock_class
);
292 key
->index_key
.type
= type
;
294 key
->quotalen
= quotalen
;
295 key
->datalen
= type
->def_datalen
;
299 key
->restrict_link
= restrict_link
;
300 key
->last_used_at
= ktime_get_real_seconds();
302 if (!(flags
& KEY_ALLOC_NOT_IN_QUOTA
))
303 key
->flags
|= 1 << KEY_FLAG_IN_QUOTA
;
304 if (flags
& KEY_ALLOC_BUILT_IN
)
305 key
->flags
|= 1 << KEY_FLAG_BUILTIN
;
306 if (flags
& KEY_ALLOC_UID_KEYRING
)
307 key
->flags
|= 1 << KEY_FLAG_UID_KEYRING
;
310 key
->magic
= KEY_DEBUG_MAGIC
;
313 /* let the security module know about the key */
314 ret
= security_key_alloc(key
, cred
, flags
);
318 /* publish the key by giving it a serial number */
319 atomic_inc(&user
->nkeys
);
320 key_alloc_serial(key
);
326 kfree(key
->description
);
327 kmem_cache_free(key_jar
, key
);
328 if (!(flags
& KEY_ALLOC_NOT_IN_QUOTA
)) {
329 spin_lock(&user
->lock
);
331 user
->qnbytes
-= quotalen
;
332 spin_unlock(&user
->lock
);
339 kmem_cache_free(key_jar
, key
);
341 if (!(flags
& KEY_ALLOC_NOT_IN_QUOTA
)) {
342 spin_lock(&user
->lock
);
344 user
->qnbytes
-= quotalen
;
345 spin_unlock(&user
->lock
);
349 key
= ERR_PTR(-ENOMEM
);
353 spin_unlock(&user
->lock
);
355 key
= ERR_PTR(-EDQUOT
);
358 EXPORT_SYMBOL(key_alloc
);
361 * key_payload_reserve - Adjust data quota reservation for the key's payload
362 * @key: The key to make the reservation for.
363 * @datalen: The amount of data payload the caller now wants.
365 * Adjust the amount of the owning user's key data quota that a key reserves.
366 * If the amount is increased, then -EDQUOT may be returned if there isn't
367 * enough free quota available.
369 * If successful, 0 is returned.
371 int key_payload_reserve(struct key
*key
, size_t datalen
)
373 int delta
= (int)datalen
- key
->datalen
;
378 /* contemplate the quota adjustment */
379 if (delta
!= 0 && test_bit(KEY_FLAG_IN_QUOTA
, &key
->flags
)) {
380 unsigned maxbytes
= uid_eq(key
->user
->uid
, GLOBAL_ROOT_UID
) ?
381 key_quota_root_maxbytes
: key_quota_maxbytes
;
383 spin_lock(&key
->user
->lock
);
386 (key
->user
->qnbytes
+ delta
>= maxbytes
||
387 key
->user
->qnbytes
+ delta
< key
->user
->qnbytes
)) {
391 key
->user
->qnbytes
+= delta
;
392 key
->quotalen
+= delta
;
394 spin_unlock(&key
->user
->lock
);
397 /* change the recorded data length if that didn't generate an error */
399 key
->datalen
= datalen
;
403 EXPORT_SYMBOL(key_payload_reserve
);
406 * Change the key state to being instantiated.
408 static void mark_key_instantiated(struct key
*key
, int reject_error
)
410 /* Commit the payload before setting the state; barrier versus
413 smp_store_release(&key
->state
,
414 (reject_error
< 0) ? reject_error
: KEY_IS_POSITIVE
);
418 * Instantiate a key and link it into the target keyring atomically. Must be
419 * called with the target keyring's semaphore writelocked. The target key's
420 * semaphore need not be locked as instantiation is serialised by
421 * key_construction_mutex.
423 static int __key_instantiate_and_link(struct key
*key
,
424 struct key_preparsed_payload
*prep
,
427 struct assoc_array_edit
**_edit
)
437 mutex_lock(&key_construction_mutex
);
439 /* can't instantiate twice */
440 if (key
->state
== KEY_IS_UNINSTANTIATED
) {
441 /* instantiate the key */
442 ret
= key
->type
->instantiate(key
, prep
);
445 /* mark the key as being instantiated */
446 atomic_inc(&key
->user
->nikeys
);
447 mark_key_instantiated(key
, 0);
449 if (test_and_clear_bit(KEY_FLAG_USER_CONSTRUCT
, &key
->flags
))
452 /* and link it into the destination keyring */
454 if (test_bit(KEY_FLAG_KEEP
, &keyring
->flags
))
455 set_bit(KEY_FLAG_KEEP
, &key
->flags
);
457 __key_link(key
, _edit
);
460 /* disable the authorisation key */
464 if (prep
->expiry
!= TIME64_MAX
) {
465 key
->expiry
= prep
->expiry
;
466 key_schedule_gc(prep
->expiry
+ key_gc_delay
);
471 mutex_unlock(&key_construction_mutex
);
473 /* wake up anyone waiting for a key to be constructed */
475 wake_up_bit(&key
->flags
, KEY_FLAG_USER_CONSTRUCT
);
481 * key_instantiate_and_link - Instantiate a key and link it into the keyring.
482 * @key: The key to instantiate.
483 * @data: The data to use to instantiate the keyring.
484 * @datalen: The length of @data.
485 * @keyring: Keyring to create a link in on success (or NULL).
486 * @authkey: The authorisation token permitting instantiation.
488 * Instantiate a key that's in the uninstantiated state using the provided data
489 * and, if successful, link it in to the destination keyring if one is
492 * If successful, 0 is returned, the authorisation token is revoked and anyone
493 * waiting for the key is woken up. If the key was already instantiated,
494 * -EBUSY will be returned.
496 int key_instantiate_and_link(struct key
*key
,
502 struct key_preparsed_payload prep
;
503 struct assoc_array_edit
*edit
;
506 memset(&prep
, 0, sizeof(prep
));
508 prep
.datalen
= datalen
;
509 prep
.quotalen
= key
->type
->def_datalen
;
510 prep
.expiry
= TIME64_MAX
;
511 if (key
->type
->preparse
) {
512 ret
= key
->type
->preparse(&prep
);
518 ret
= __key_link_begin(keyring
, &key
->index_key
, &edit
);
522 if (keyring
->restrict_link
&& keyring
->restrict_link
->check
) {
523 struct key_restriction
*keyres
= keyring
->restrict_link
;
525 ret
= keyres
->check(keyring
, key
->type
, &prep
.payload
,
532 ret
= __key_instantiate_and_link(key
, &prep
, keyring
, authkey
, &edit
);
536 __key_link_end(keyring
, &key
->index_key
, edit
);
539 if (key
->type
->preparse
)
540 key
->type
->free_preparse(&prep
);
544 EXPORT_SYMBOL(key_instantiate_and_link
);
547 * key_reject_and_link - Negatively instantiate a key and link it into the keyring.
548 * @key: The key to instantiate.
549 * @timeout: The timeout on the negative key.
550 * @error: The error to return when the key is hit.
551 * @keyring: Keyring to create a link in on success (or NULL).
552 * @authkey: The authorisation token permitting instantiation.
554 * Negatively instantiate a key that's in the uninstantiated state and, if
555 * successful, set its timeout and stored error and link it in to the
556 * destination keyring if one is supplied. The key and any links to the key
557 * will be automatically garbage collected after the timeout expires.
559 * Negative keys are used to rate limit repeated request_key() calls by causing
560 * them to return the stored error code (typically ENOKEY) until the negative
563 * If successful, 0 is returned, the authorisation token is revoked and anyone
564 * waiting for the key is woken up. If the key was already instantiated,
565 * -EBUSY will be returned.
567 int key_reject_and_link(struct key
*key
,
573 struct assoc_array_edit
*edit
;
574 int ret
, awaken
, link_ret
= 0;
583 if (keyring
->restrict_link
)
586 link_ret
= __key_link_begin(keyring
, &key
->index_key
, &edit
);
589 mutex_lock(&key_construction_mutex
);
591 /* can't instantiate twice */
592 if (key
->state
== KEY_IS_UNINSTANTIATED
) {
593 /* mark the key as being negatively instantiated */
594 atomic_inc(&key
->user
->nikeys
);
595 mark_key_instantiated(key
, -error
);
596 key
->expiry
= ktime_get_real_seconds() + timeout
;
597 key_schedule_gc(key
->expiry
+ key_gc_delay
);
599 if (test_and_clear_bit(KEY_FLAG_USER_CONSTRUCT
, &key
->flags
))
604 /* and link it into the destination keyring */
605 if (keyring
&& link_ret
== 0)
606 __key_link(key
, &edit
);
608 /* disable the authorisation key */
613 mutex_unlock(&key_construction_mutex
);
615 if (keyring
&& link_ret
== 0)
616 __key_link_end(keyring
, &key
->index_key
, edit
);
618 /* wake up anyone waiting for a key to be constructed */
620 wake_up_bit(&key
->flags
, KEY_FLAG_USER_CONSTRUCT
);
622 return ret
== 0 ? link_ret
: ret
;
624 EXPORT_SYMBOL(key_reject_and_link
);
627 * key_put - Discard a reference to a key.
628 * @key: The key to discard a reference from.
630 * Discard a reference to a key, and when all the references are gone, we
631 * schedule the cleanup task to come and pull it out of the tree in process
632 * context at some later time.
634 void key_put(struct key
*key
)
639 if (refcount_dec_and_test(&key
->usage
))
640 schedule_work(&key_gc_work
);
643 EXPORT_SYMBOL(key_put
);
646 * Find a key by its serial number.
648 struct key
*key_lookup(key_serial_t id
)
653 spin_lock(&key_serial_lock
);
655 /* search the tree for the specified key */
656 n
= key_serial_tree
.rb_node
;
658 key
= rb_entry(n
, struct key
, serial_node
);
660 if (id
< key
->serial
)
662 else if (id
> key
->serial
)
669 key
= ERR_PTR(-ENOKEY
);
673 /* A key is allowed to be looked up only if someone still owns a
674 * reference to it - otherwise it's awaiting the gc.
676 if (!refcount_inc_not_zero(&key
->usage
))
680 spin_unlock(&key_serial_lock
);
685 * Find and lock the specified key type against removal.
687 * We return with the sem read-locked if successful. If the type wasn't
688 * available -ENOKEY is returned instead.
690 struct key_type
*key_type_lookup(const char *type
)
692 struct key_type
*ktype
;
694 down_read(&key_types_sem
);
696 /* look up the key type to see if it's one of the registered kernel
698 list_for_each_entry(ktype
, &key_types_list
, link
) {
699 if (strcmp(ktype
->name
, type
) == 0)
700 goto found_kernel_type
;
703 up_read(&key_types_sem
);
704 ktype
= ERR_PTR(-ENOKEY
);
710 void key_set_timeout(struct key
*key
, unsigned timeout
)
714 /* make the changes with the locks held to prevent races */
715 down_write(&key
->sem
);
718 expiry
= ktime_get_real_seconds() + timeout
;
720 key
->expiry
= expiry
;
721 key_schedule_gc(key
->expiry
+ key_gc_delay
);
725 EXPORT_SYMBOL_GPL(key_set_timeout
);
728 * Unlock a key type locked by key_type_lookup().
730 void key_type_put(struct key_type
*ktype
)
732 up_read(&key_types_sem
);
736 * Attempt to update an existing key.
738 * The key is given to us with an incremented refcount that we need to discard
739 * if we get an error.
741 static inline key_ref_t
__key_update(key_ref_t key_ref
,
742 struct key_preparsed_payload
*prep
)
744 struct key
*key
= key_ref_to_ptr(key_ref
);
747 /* need write permission on the key to update it */
748 ret
= key_permission(key_ref
, KEY_NEED_WRITE
);
753 if (!key
->type
->update
)
756 down_write(&key
->sem
);
758 ret
= key
->type
->update(key
, prep
);
760 /* Updating a negative key positively instantiates it */
761 mark_key_instantiated(key
, 0);
772 key_ref
= ERR_PTR(ret
);
777 * key_create_or_update - Update or create and instantiate a key.
778 * @keyring_ref: A pointer to the destination keyring with possession flag.
779 * @type: The type of key.
780 * @description: The searchable description for the key.
781 * @payload: The data to use to instantiate or update the key.
782 * @plen: The length of @payload.
783 * @perm: The permissions mask for a new key.
784 * @flags: The quota flags for a new key.
786 * Search the destination keyring for a key of the same description and if one
787 * is found, update it, otherwise create and instantiate a new one and create a
788 * link to it from that keyring.
790 * If perm is KEY_PERM_UNDEF then an appropriate key permissions mask will be
793 * Returns a pointer to the new key if successful, -ENODEV if the key type
794 * wasn't available, -ENOTDIR if the keyring wasn't a keyring, -EACCES if the
795 * caller isn't permitted to modify the keyring or the LSM did not permit
796 * creation of the key.
798 * On success, the possession flag from the keyring ref will be tacked on to
799 * the key ref before it is returned.
801 key_ref_t
key_create_or_update(key_ref_t keyring_ref
,
803 const char *description
,
809 struct keyring_index_key index_key
= {
810 .description
= description
,
812 struct key_preparsed_payload prep
;
813 struct assoc_array_edit
*edit
;
814 const struct cred
*cred
= current_cred();
815 struct key
*keyring
, *key
= NULL
;
818 struct key_restriction
*restrict_link
= NULL
;
820 /* look up the key type to see if it's one of the registered kernel
822 index_key
.type
= key_type_lookup(type
);
823 if (IS_ERR(index_key
.type
)) {
824 key_ref
= ERR_PTR(-ENODEV
);
828 key_ref
= ERR_PTR(-EINVAL
);
829 if (!index_key
.type
->instantiate
||
830 (!index_key
.description
&& !index_key
.type
->preparse
))
833 keyring
= key_ref_to_ptr(keyring_ref
);
837 if (!(flags
& KEY_ALLOC_BYPASS_RESTRICTION
))
838 restrict_link
= keyring
->restrict_link
;
840 key_ref
= ERR_PTR(-ENOTDIR
);
841 if (keyring
->type
!= &key_type_keyring
)
844 memset(&prep
, 0, sizeof(prep
));
847 prep
.quotalen
= index_key
.type
->def_datalen
;
848 prep
.expiry
= TIME64_MAX
;
849 if (index_key
.type
->preparse
) {
850 ret
= index_key
.type
->preparse(&prep
);
852 key_ref
= ERR_PTR(ret
);
853 goto error_free_prep
;
855 if (!index_key
.description
)
856 index_key
.description
= prep
.description
;
857 key_ref
= ERR_PTR(-EINVAL
);
858 if (!index_key
.description
)
859 goto error_free_prep
;
861 index_key
.desc_len
= strlen(index_key
.description
);
863 ret
= __key_link_begin(keyring
, &index_key
, &edit
);
865 key_ref
= ERR_PTR(ret
);
866 goto error_free_prep
;
869 if (restrict_link
&& restrict_link
->check
) {
870 ret
= restrict_link
->check(keyring
, index_key
.type
,
871 &prep
.payload
, restrict_link
->key
);
873 key_ref
= ERR_PTR(ret
);
878 /* if we're going to allocate a new key, we're going to have
879 * to modify the keyring */
880 ret
= key_permission(keyring_ref
, KEY_NEED_WRITE
);
882 key_ref
= ERR_PTR(ret
);
886 /* if it's possible to update this type of key, search for an existing
887 * key of the same type and description in the destination keyring and
888 * update that instead if possible
890 if (index_key
.type
->update
) {
891 key_ref
= find_key_to_update(keyring_ref
, &index_key
);
893 goto found_matching_key
;
896 /* if the client doesn't provide, decide on the permissions we want */
897 if (perm
== KEY_PERM_UNDEF
) {
898 perm
= KEY_POS_VIEW
| KEY_POS_SEARCH
| KEY_POS_LINK
| KEY_POS_SETATTR
;
899 perm
|= KEY_USR_VIEW
;
901 if (index_key
.type
->read
)
902 perm
|= KEY_POS_READ
;
904 if (index_key
.type
== &key_type_keyring
||
905 index_key
.type
->update
)
906 perm
|= KEY_POS_WRITE
;
909 /* allocate a new key */
910 key
= key_alloc(index_key
.type
, index_key
.description
,
911 cred
->fsuid
, cred
->fsgid
, cred
, perm
, flags
, NULL
);
913 key_ref
= ERR_CAST(key
);
917 /* instantiate it and link it into the target keyring */
918 ret
= __key_instantiate_and_link(key
, &prep
, keyring
, NULL
, &edit
);
921 key_ref
= ERR_PTR(ret
);
925 key_ref
= make_key_ref(key
, is_key_possessed(keyring_ref
));
928 __key_link_end(keyring
, &index_key
, edit
);
930 if (index_key
.type
->preparse
)
931 index_key
.type
->free_preparse(&prep
);
933 key_type_put(index_key
.type
);
938 /* we found a matching key, so we're going to try to update it
939 * - we can drop the locks first as we have the key pinned
941 __key_link_end(keyring
, &index_key
, edit
);
943 key
= key_ref_to_ptr(key_ref
);
944 if (test_bit(KEY_FLAG_USER_CONSTRUCT
, &key
->flags
)) {
945 ret
= wait_for_key_construction(key
, true);
947 key_ref_put(key_ref
);
948 key_ref
= ERR_PTR(ret
);
949 goto error_free_prep
;
953 key_ref
= __key_update(key_ref
, &prep
);
954 goto error_free_prep
;
956 EXPORT_SYMBOL(key_create_or_update
);
959 * key_update - Update a key's contents.
960 * @key_ref: The pointer (plus possession flag) to the key.
961 * @payload: The data to be used to update the key.
962 * @plen: The length of @payload.
964 * Attempt to update the contents of a key with the given payload data. The
965 * caller must be granted Write permission on the key. Negative keys can be
966 * instantiated by this method.
968 * Returns 0 on success, -EACCES if not permitted and -EOPNOTSUPP if the key
969 * type does not support updating. The key type may return other errors.
971 int key_update(key_ref_t key_ref
, const void *payload
, size_t plen
)
973 struct key_preparsed_payload prep
;
974 struct key
*key
= key_ref_to_ptr(key_ref
);
979 /* the key must be writable */
980 ret
= key_permission(key_ref
, KEY_NEED_WRITE
);
984 /* attempt to update it if supported */
985 if (!key
->type
->update
)
988 memset(&prep
, 0, sizeof(prep
));
991 prep
.quotalen
= key
->type
->def_datalen
;
992 prep
.expiry
= TIME64_MAX
;
993 if (key
->type
->preparse
) {
994 ret
= key
->type
->preparse(&prep
);
999 down_write(&key
->sem
);
1001 ret
= key
->type
->update(key
, &prep
);
1003 /* Updating a negative key positively instantiates it */
1004 mark_key_instantiated(key
, 0);
1006 up_write(&key
->sem
);
1009 if (key
->type
->preparse
)
1010 key
->type
->free_preparse(&prep
);
1013 EXPORT_SYMBOL(key_update
);
1016 * key_revoke - Revoke a key.
1017 * @key: The key to be revoked.
1019 * Mark a key as being revoked and ask the type to free up its resources. The
1020 * revocation timeout is set and the key and all its links will be
1021 * automatically garbage collected after key_gc_delay amount of time if they
1022 * are not manually dealt with first.
1024 void key_revoke(struct key
*key
)
1030 /* make sure no one's trying to change or use the key when we mark it
1031 * - we tell lockdep that we might nest because we might be revoking an
1032 * authorisation key whilst holding the sem on a key we've just
1035 down_write_nested(&key
->sem
, 1);
1036 if (!test_and_set_bit(KEY_FLAG_REVOKED
, &key
->flags
) &&
1038 key
->type
->revoke(key
);
1040 /* set the death time to no more than the expiry time */
1041 time
= ktime_get_real_seconds();
1042 if (key
->revoked_at
== 0 || key
->revoked_at
> time
) {
1043 key
->revoked_at
= time
;
1044 key_schedule_gc(key
->revoked_at
+ key_gc_delay
);
1047 up_write(&key
->sem
);
1049 EXPORT_SYMBOL(key_revoke
);
1052 * key_invalidate - Invalidate a key.
1053 * @key: The key to be invalidated.
1055 * Mark a key as being invalidated and have it cleaned up immediately. The key
1056 * is ignored by all searches and other operations from this point.
1058 void key_invalidate(struct key
*key
)
1060 kenter("%d", key_serial(key
));
1064 if (!test_bit(KEY_FLAG_INVALIDATED
, &key
->flags
)) {
1065 down_write_nested(&key
->sem
, 1);
1066 if (!test_and_set_bit(KEY_FLAG_INVALIDATED
, &key
->flags
))
1067 key_schedule_gc_links();
1068 up_write(&key
->sem
);
1071 EXPORT_SYMBOL(key_invalidate
);
1074 * generic_key_instantiate - Simple instantiation of a key from preparsed data
1075 * @key: The key to be instantiated
1076 * @prep: The preparsed data to load.
1078 * Instantiate a key from preparsed data. We assume we can just copy the data
1079 * in directly and clear the old pointers.
1081 * This can be pointed to directly by the key type instantiate op pointer.
1083 int generic_key_instantiate(struct key
*key
, struct key_preparsed_payload
*prep
)
1087 pr_devel("==>%s()\n", __func__
);
1089 ret
= key_payload_reserve(key
, prep
->quotalen
);
1091 rcu_assign_keypointer(key
, prep
->payload
.data
[0]);
1092 key
->payload
.data
[1] = prep
->payload
.data
[1];
1093 key
->payload
.data
[2] = prep
->payload
.data
[2];
1094 key
->payload
.data
[3] = prep
->payload
.data
[3];
1095 prep
->payload
.data
[0] = NULL
;
1096 prep
->payload
.data
[1] = NULL
;
1097 prep
->payload
.data
[2] = NULL
;
1098 prep
->payload
.data
[3] = NULL
;
1100 pr_devel("<==%s() = %d\n", __func__
, ret
);
1103 EXPORT_SYMBOL(generic_key_instantiate
);
1106 * register_key_type - Register a type of key.
1107 * @ktype: The new key type.
1109 * Register a new key type.
1111 * Returns 0 on success or -EEXIST if a type of this name already exists.
1113 int register_key_type(struct key_type
*ktype
)
1118 memset(&ktype
->lock_class
, 0, sizeof(ktype
->lock_class
));
1121 down_write(&key_types_sem
);
1123 /* disallow key types with the same name */
1124 list_for_each_entry(p
, &key_types_list
, link
) {
1125 if (strcmp(p
->name
, ktype
->name
) == 0)
1129 /* store the type */
1130 list_add(&ktype
->link
, &key_types_list
);
1132 pr_notice("Key type %s registered\n", ktype
->name
);
1136 up_write(&key_types_sem
);
1139 EXPORT_SYMBOL(register_key_type
);
1142 * unregister_key_type - Unregister a type of key.
1143 * @ktype: The key type.
1145 * Unregister a key type and mark all the extant keys of this type as dead.
1146 * Those keys of this type are then destroyed to get rid of their payloads and
1147 * they and their links will be garbage collected as soon as possible.
1149 void unregister_key_type(struct key_type
*ktype
)
1151 down_write(&key_types_sem
);
1152 list_del_init(&ktype
->link
);
1153 downgrade_write(&key_types_sem
);
1154 key_gc_keytype(ktype
);
1155 pr_notice("Key type %s unregistered\n", ktype
->name
);
1156 up_read(&key_types_sem
);
1158 EXPORT_SYMBOL(unregister_key_type
);
1161 * Initialise the key management state.
1163 void __init
key_init(void)
1165 /* allocate a slab in which we can store keys */
1166 key_jar
= kmem_cache_create("key_jar", sizeof(struct key
),
1167 0, SLAB_HWCACHE_ALIGN
|SLAB_PANIC
, NULL
);
1169 /* add the special key types */
1170 list_add_tail(&key_type_keyring
.link
, &key_types_list
);
1171 list_add_tail(&key_type_dead
.link
, &key_types_list
);
1172 list_add_tail(&key_type_user
.link
, &key_types_list
);
1173 list_add_tail(&key_type_logon
.link
, &key_types_list
);
1175 /* record the root user tracking */
1176 rb_link_node(&root_key_user
.node
,
1178 &key_user_tree
.rb_node
);
1180 rb_insert_color(&root_key_user
.node
,