1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /* Basic authentication token and access key management
4 * Copyright (C) 2004-2008 Red Hat, Inc. All Rights Reserved.
5 * Written by David Howells (dhowells@redhat.com)
8 #include <linux/export.h>
9 #include <linux/init.h>
10 #include <linux/poison.h>
11 #include <linux/sched.h>
12 #include <linux/slab.h>
13 #include <linux/security.h>
14 #include <linux/workqueue.h>
15 #include <linux/random.h>
16 #include <linux/err.h>
19 struct kmem_cache
*key_jar
;
20 struct rb_root key_serial_tree
; /* tree of keys indexed by serial */
21 DEFINE_SPINLOCK(key_serial_lock
);
23 struct rb_root key_user_tree
; /* tree of quota records indexed by UID */
24 DEFINE_SPINLOCK(key_user_lock
);
26 unsigned int key_quota_root_maxkeys
= 1000000; /* root's key count quota */
27 unsigned int key_quota_root_maxbytes
= 25000000; /* root's key space quota */
28 unsigned int key_quota_maxkeys
= 200; /* general key count quota */
29 unsigned int key_quota_maxbytes
= 20000; /* general key space quota */
31 static LIST_HEAD(key_types_list
);
32 static DECLARE_RWSEM(key_types_sem
);
34 /* We serialise key instantiation and link */
35 DEFINE_MUTEX(key_construction_mutex
);
38 void __key_check(const struct key
*key
)
40 printk("__key_check: key %p {%08x} should be {%08x}\n",
41 key
, key
->magic
, KEY_DEBUG_MAGIC
);
47 * Get the key quota record for a user, allocating a new record if one doesn't
50 struct key_user
*key_user_lookup(kuid_t uid
)
52 struct key_user
*candidate
= NULL
, *user
;
53 struct rb_node
*parent
, **p
;
57 p
= &key_user_tree
.rb_node
;
58 spin_lock(&key_user_lock
);
60 /* search the tree for a user record with a matching UID */
63 user
= rb_entry(parent
, struct key_user
, node
);
65 if (uid_lt(uid
, user
->uid
))
67 else if (uid_gt(uid
, user
->uid
))
73 /* if we get here, we failed to find a match in the tree */
75 /* allocate a candidate user record if we don't already have
77 spin_unlock(&key_user_lock
);
80 candidate
= kmalloc(sizeof(struct key_user
), GFP_KERNEL
);
81 if (unlikely(!candidate
))
84 /* the allocation may have scheduled, so we need to repeat the
85 * search lest someone else added the record whilst we were
90 /* if we get here, then the user record still hadn't appeared on the
91 * second pass - so we use the candidate record */
92 refcount_set(&candidate
->usage
, 1);
93 atomic_set(&candidate
->nkeys
, 0);
94 atomic_set(&candidate
->nikeys
, 0);
96 candidate
->qnkeys
= 0;
97 candidate
->qnbytes
= 0;
98 spin_lock_init(&candidate
->lock
);
99 mutex_init(&candidate
->cons_lock
);
101 rb_link_node(&candidate
->node
, parent
, p
);
102 rb_insert_color(&candidate
->node
, &key_user_tree
);
103 spin_unlock(&key_user_lock
);
107 /* okay - we found a user record for this UID */
109 refcount_inc(&user
->usage
);
110 spin_unlock(&key_user_lock
);
117 * Dispose of a user structure
119 void key_user_put(struct key_user
*user
)
121 if (refcount_dec_and_lock(&user
->usage
, &key_user_lock
)) {
122 rb_erase(&user
->node
, &key_user_tree
);
123 spin_unlock(&key_user_lock
);
130 * Allocate a serial number for a key. These are assigned randomly to avoid
131 * security issues through covert channel problems.
133 static inline void key_alloc_serial(struct key
*key
)
135 struct rb_node
*parent
, **p
;
138 /* propose a random serial number and look for a hole for it in the
139 * serial number tree */
141 get_random_bytes(&key
->serial
, sizeof(key
->serial
));
143 key
->serial
>>= 1; /* negative numbers are not permitted */
144 } while (key
->serial
< 3);
146 spin_lock(&key_serial_lock
);
150 p
= &key_serial_tree
.rb_node
;
154 xkey
= rb_entry(parent
, struct key
, serial_node
);
156 if (key
->serial
< xkey
->serial
)
158 else if (key
->serial
> xkey
->serial
)
164 /* we've found a suitable hole - arrange for this key to occupy it */
165 rb_link_node(&key
->serial_node
, parent
, p
);
166 rb_insert_color(&key
->serial_node
, &key_serial_tree
);
168 spin_unlock(&key_serial_lock
);
171 /* we found a key with the proposed serial number - walk the tree from
172 * that point looking for the next unused serial number */
176 if (key
->serial
< 3) {
178 goto attempt_insertion
;
181 parent
= rb_next(parent
);
183 goto attempt_insertion
;
185 xkey
= rb_entry(parent
, struct key
, serial_node
);
186 if (key
->serial
< xkey
->serial
)
187 goto attempt_insertion
;
192 * key_alloc - Allocate a key of the specified type.
193 * @type: The type of key to allocate.
194 * @desc: The key description to allow the key to be searched out.
195 * @uid: The owner of the new key.
196 * @gid: The group ID for the new key's group permissions.
197 * @cred: The credentials specifying UID namespace.
198 * @perm: The permissions mask of the new key.
199 * @flags: Flags specifying quota properties.
200 * @restrict_link: Optional link restriction for new keyrings.
202 * Allocate a key of the specified type with the attributes given. The key is
203 * returned in an uninstantiated state and the caller needs to instantiate the
204 * key before returning.
206 * The restrict_link structure (if not NULL) will be freed when the
207 * keyring is destroyed, so it must be dynamically allocated.
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
,
227 struct key_restriction
*restrict_link
)
229 struct key_user
*user
= NULL
;
231 size_t desclen
, quotalen
;
234 key
= ERR_PTR(-EINVAL
);
238 if (type
->vet_description
) {
239 ret
= type
->vet_description(desc
);
246 desclen
= strlen(desc
);
247 quotalen
= desclen
+ 1 + type
->def_datalen
;
249 /* get hold of the key tracking for this user */
250 user
= key_user_lookup(uid
);
254 /* check that the user's quota permits allocation of another key and
256 if (!(flags
& KEY_ALLOC_NOT_IN_QUOTA
)) {
257 unsigned maxkeys
= uid_eq(uid
, GLOBAL_ROOT_UID
) ?
258 key_quota_root_maxkeys
: key_quota_maxkeys
;
259 unsigned maxbytes
= uid_eq(uid
, GLOBAL_ROOT_UID
) ?
260 key_quota_root_maxbytes
: key_quota_maxbytes
;
262 spin_lock(&user
->lock
);
263 if (!(flags
& KEY_ALLOC_QUOTA_OVERRUN
)) {
264 if (user
->qnkeys
+ 1 > maxkeys
||
265 user
->qnbytes
+ quotalen
> maxbytes
||
266 user
->qnbytes
+ quotalen
< user
->qnbytes
)
271 user
->qnbytes
+= quotalen
;
272 spin_unlock(&user
->lock
);
275 /* allocate and initialise the key and its description */
276 key
= kmem_cache_zalloc(key_jar
, GFP_KERNEL
);
280 key
->index_key
.desc_len
= desclen
;
281 key
->index_key
.description
= kmemdup(desc
, desclen
+ 1, GFP_KERNEL
);
282 if (!key
->index_key
.description
)
284 key
->index_key
.type
= type
;
285 key_set_index_key(&key
->index_key
);
287 refcount_set(&key
->usage
, 1);
288 init_rwsem(&key
->sem
);
289 lockdep_set_class(&key
->sem
, &type
->lock_class
);
291 key
->quotalen
= quotalen
;
292 key
->datalen
= type
->def_datalen
;
296 key
->restrict_link
= restrict_link
;
297 key
->last_used_at
= ktime_get_real_seconds();
299 if (!(flags
& KEY_ALLOC_NOT_IN_QUOTA
))
300 key
->flags
|= 1 << KEY_FLAG_IN_QUOTA
;
301 if (flags
& KEY_ALLOC_BUILT_IN
)
302 key
->flags
|= 1 << KEY_FLAG_BUILTIN
;
303 if (flags
& KEY_ALLOC_UID_KEYRING
)
304 key
->flags
|= 1 << KEY_FLAG_UID_KEYRING
;
307 key
->magic
= KEY_DEBUG_MAGIC
;
310 /* let the security module know about the key */
311 ret
= security_key_alloc(key
, cred
, flags
);
315 /* publish the key by giving it a serial number */
316 refcount_inc(&key
->domain_tag
->usage
);
317 atomic_inc(&user
->nkeys
);
318 key_alloc_serial(key
);
324 kfree(key
->description
);
325 kmem_cache_free(key_jar
, key
);
326 if (!(flags
& KEY_ALLOC_NOT_IN_QUOTA
)) {
327 spin_lock(&user
->lock
);
329 user
->qnbytes
-= quotalen
;
330 spin_unlock(&user
->lock
);
337 kmem_cache_free(key_jar
, key
);
339 if (!(flags
& KEY_ALLOC_NOT_IN_QUOTA
)) {
340 spin_lock(&user
->lock
);
342 user
->qnbytes
-= quotalen
;
343 spin_unlock(&user
->lock
);
347 key
= ERR_PTR(-ENOMEM
);
351 spin_unlock(&user
->lock
);
353 key
= ERR_PTR(-EDQUOT
);
356 EXPORT_SYMBOL(key_alloc
);
359 * key_payload_reserve - Adjust data quota reservation for the key's payload
360 * @key: The key to make the reservation for.
361 * @datalen: The amount of data payload the caller now wants.
363 * Adjust the amount of the owning user's key data quota that a key reserves.
364 * If the amount is increased, then -EDQUOT may be returned if there isn't
365 * enough free quota available.
367 * If successful, 0 is returned.
369 int key_payload_reserve(struct key
*key
, size_t datalen
)
371 int delta
= (int)datalen
- key
->datalen
;
376 /* contemplate the quota adjustment */
377 if (delta
!= 0 && test_bit(KEY_FLAG_IN_QUOTA
, &key
->flags
)) {
378 unsigned maxbytes
= uid_eq(key
->user
->uid
, GLOBAL_ROOT_UID
) ?
379 key_quota_root_maxbytes
: key_quota_maxbytes
;
381 spin_lock(&key
->user
->lock
);
384 (key
->user
->qnbytes
+ delta
>= maxbytes
||
385 key
->user
->qnbytes
+ delta
< key
->user
->qnbytes
)) {
389 key
->user
->qnbytes
+= delta
;
390 key
->quotalen
+= delta
;
392 spin_unlock(&key
->user
->lock
);
395 /* change the recorded data length if that didn't generate an error */
397 key
->datalen
= datalen
;
401 EXPORT_SYMBOL(key_payload_reserve
);
404 * Change the key state to being instantiated.
406 static void mark_key_instantiated(struct key
*key
, int reject_error
)
408 /* Commit the payload before setting the state; barrier versus
411 smp_store_release(&key
->state
,
412 (reject_error
< 0) ? reject_error
: KEY_IS_POSITIVE
);
416 * Instantiate a key and link it into the target keyring atomically. Must be
417 * called with the target keyring's semaphore writelocked. The target key's
418 * semaphore need not be locked as instantiation is serialised by
419 * key_construction_mutex.
421 static int __key_instantiate_and_link(struct key
*key
,
422 struct key_preparsed_payload
*prep
,
425 struct assoc_array_edit
**_edit
)
435 mutex_lock(&key_construction_mutex
);
437 /* can't instantiate twice */
438 if (key
->state
== KEY_IS_UNINSTANTIATED
) {
439 /* instantiate the key */
440 ret
= key
->type
->instantiate(key
, prep
);
443 /* mark the key as being instantiated */
444 atomic_inc(&key
->user
->nikeys
);
445 mark_key_instantiated(key
, 0);
447 if (test_and_clear_bit(KEY_FLAG_USER_CONSTRUCT
, &key
->flags
))
450 /* and link it into the destination keyring */
452 if (test_bit(KEY_FLAG_KEEP
, &keyring
->flags
))
453 set_bit(KEY_FLAG_KEEP
, &key
->flags
);
455 __key_link(key
, _edit
);
458 /* disable the authorisation key */
460 key_invalidate(authkey
);
462 if (prep
->expiry
!= TIME64_MAX
) {
463 key
->expiry
= prep
->expiry
;
464 key_schedule_gc(prep
->expiry
+ key_gc_delay
);
469 mutex_unlock(&key_construction_mutex
);
471 /* wake up anyone waiting for a key to be constructed */
473 wake_up_bit(&key
->flags
, KEY_FLAG_USER_CONSTRUCT
);
479 * key_instantiate_and_link - Instantiate a key and link it into the keyring.
480 * @key: The key to instantiate.
481 * @data: The data to use to instantiate the keyring.
482 * @datalen: The length of @data.
483 * @keyring: Keyring to create a link in on success (or NULL).
484 * @authkey: The authorisation token permitting instantiation.
486 * Instantiate a key that's in the uninstantiated state using the provided data
487 * and, if successful, link it in to the destination keyring if one is
490 * If successful, 0 is returned, the authorisation token is revoked and anyone
491 * waiting for the key is woken up. If the key was already instantiated,
492 * -EBUSY will be returned.
494 int key_instantiate_and_link(struct key
*key
,
500 struct key_preparsed_payload prep
;
501 struct assoc_array_edit
*edit
= NULL
;
504 memset(&prep
, 0, sizeof(prep
));
506 prep
.datalen
= datalen
;
507 prep
.quotalen
= key
->type
->def_datalen
;
508 prep
.expiry
= TIME64_MAX
;
509 if (key
->type
->preparse
) {
510 ret
= key
->type
->preparse(&prep
);
516 ret
= __key_link_lock(keyring
, &key
->index_key
);
520 ret
= __key_link_begin(keyring
, &key
->index_key
, &edit
);
524 if (keyring
->restrict_link
&& keyring
->restrict_link
->check
) {
525 struct key_restriction
*keyres
= keyring
->restrict_link
;
527 ret
= keyres
->check(keyring
, key
->type
, &prep
.payload
,
534 ret
= __key_instantiate_and_link(key
, &prep
, keyring
, authkey
, &edit
);
538 __key_link_end(keyring
, &key
->index_key
, edit
);
541 if (key
->type
->preparse
)
542 key
->type
->free_preparse(&prep
);
546 EXPORT_SYMBOL(key_instantiate_and_link
);
549 * key_reject_and_link - Negatively instantiate a key and link it into the keyring.
550 * @key: The key to instantiate.
551 * @timeout: The timeout on the negative key.
552 * @error: The error to return when the key is hit.
553 * @keyring: Keyring to create a link in on success (or NULL).
554 * @authkey: The authorisation token permitting instantiation.
556 * Negatively instantiate a key that's in the uninstantiated state and, if
557 * successful, set its timeout and stored error and link it in to the
558 * destination keyring if one is supplied. The key and any links to the key
559 * will be automatically garbage collected after the timeout expires.
561 * Negative keys are used to rate limit repeated request_key() calls by causing
562 * them to return the stored error code (typically ENOKEY) until the negative
565 * If successful, 0 is returned, the authorisation token is revoked and anyone
566 * waiting for the key is woken up. If the key was already instantiated,
567 * -EBUSY will be returned.
569 int key_reject_and_link(struct key
*key
,
575 struct assoc_array_edit
*edit
= NULL
;
576 int ret
, awaken
, link_ret
= 0;
585 if (keyring
->restrict_link
)
588 link_ret
= __key_link_lock(keyring
, &key
->index_key
);
590 link_ret
= __key_link_begin(keyring
, &key
->index_key
, &edit
);
592 __key_link_end(keyring
, &key
->index_key
, edit
);
596 mutex_lock(&key_construction_mutex
);
598 /* can't instantiate twice */
599 if (key
->state
== KEY_IS_UNINSTANTIATED
) {
600 /* mark the key as being negatively instantiated */
601 atomic_inc(&key
->user
->nikeys
);
602 mark_key_instantiated(key
, -error
);
603 key
->expiry
= ktime_get_real_seconds() + timeout
;
604 key_schedule_gc(key
->expiry
+ key_gc_delay
);
606 if (test_and_clear_bit(KEY_FLAG_USER_CONSTRUCT
, &key
->flags
))
611 /* and link it into the destination keyring */
612 if (keyring
&& link_ret
== 0)
613 __key_link(key
, &edit
);
615 /* disable the authorisation key */
617 key_invalidate(authkey
);
620 mutex_unlock(&key_construction_mutex
);
622 if (keyring
&& link_ret
== 0)
623 __key_link_end(keyring
, &key
->index_key
, edit
);
625 /* wake up anyone waiting for a key to be constructed */
627 wake_up_bit(&key
->flags
, KEY_FLAG_USER_CONSTRUCT
);
629 return ret
== 0 ? link_ret
: ret
;
631 EXPORT_SYMBOL(key_reject_and_link
);
634 * key_put - Discard a reference to a key.
635 * @key: The key to discard a reference from.
637 * Discard a reference to a key, and when all the references are gone, we
638 * schedule the cleanup task to come and pull it out of the tree in process
639 * context at some later time.
641 void key_put(struct key
*key
)
646 if (refcount_dec_and_test(&key
->usage
))
647 schedule_work(&key_gc_work
);
650 EXPORT_SYMBOL(key_put
);
653 * Find a key by its serial number.
655 struct key
*key_lookup(key_serial_t id
)
660 spin_lock(&key_serial_lock
);
662 /* search the tree for the specified key */
663 n
= key_serial_tree
.rb_node
;
665 key
= rb_entry(n
, struct key
, serial_node
);
667 if (id
< key
->serial
)
669 else if (id
> key
->serial
)
676 key
= ERR_PTR(-ENOKEY
);
680 /* A key is allowed to be looked up only if someone still owns a
681 * reference to it - otherwise it's awaiting the gc.
683 if (!refcount_inc_not_zero(&key
->usage
))
687 spin_unlock(&key_serial_lock
);
692 * Find and lock the specified key type against removal.
694 * We return with the sem read-locked if successful. If the type wasn't
695 * available -ENOKEY is returned instead.
697 struct key_type
*key_type_lookup(const char *type
)
699 struct key_type
*ktype
;
701 down_read(&key_types_sem
);
703 /* look up the key type to see if it's one of the registered kernel
705 list_for_each_entry(ktype
, &key_types_list
, link
) {
706 if (strcmp(ktype
->name
, type
) == 0)
707 goto found_kernel_type
;
710 up_read(&key_types_sem
);
711 ktype
= ERR_PTR(-ENOKEY
);
717 void key_set_timeout(struct key
*key
, unsigned timeout
)
721 /* make the changes with the locks held to prevent races */
722 down_write(&key
->sem
);
725 expiry
= ktime_get_real_seconds() + timeout
;
727 key
->expiry
= expiry
;
728 key_schedule_gc(key
->expiry
+ key_gc_delay
);
732 EXPORT_SYMBOL_GPL(key_set_timeout
);
735 * Unlock a key type locked by key_type_lookup().
737 void key_type_put(struct key_type
*ktype
)
739 up_read(&key_types_sem
);
743 * Attempt to update an existing key.
745 * The key is given to us with an incremented refcount that we need to discard
746 * if we get an error.
748 static inline key_ref_t
__key_update(key_ref_t key_ref
,
749 struct key_preparsed_payload
*prep
)
751 struct key
*key
= key_ref_to_ptr(key_ref
);
754 /* need write permission on the key to update it */
755 ret
= key_permission(key_ref
, KEY_NEED_WRITE
);
760 if (!key
->type
->update
)
763 down_write(&key
->sem
);
765 ret
= key
->type
->update(key
, prep
);
767 /* Updating a negative key positively instantiates it */
768 mark_key_instantiated(key
, 0);
779 key_ref
= ERR_PTR(ret
);
784 * key_create_or_update - Update or create and instantiate a key.
785 * @keyring_ref: A pointer to the destination keyring with possession flag.
786 * @type: The type of key.
787 * @description: The searchable description for the key.
788 * @payload: The data to use to instantiate or update the key.
789 * @plen: The length of @payload.
790 * @perm: The permissions mask for a new key.
791 * @flags: The quota flags for a new key.
793 * Search the destination keyring for a key of the same description and if one
794 * is found, update it, otherwise create and instantiate a new one and create a
795 * link to it from that keyring.
797 * If perm is KEY_PERM_UNDEF then an appropriate key permissions mask will be
800 * Returns a pointer to the new key if successful, -ENODEV if the key type
801 * wasn't available, -ENOTDIR if the keyring wasn't a keyring, -EACCES if the
802 * caller isn't permitted to modify the keyring or the LSM did not permit
803 * creation of the key.
805 * On success, the possession flag from the keyring ref will be tacked on to
806 * the key ref before it is returned.
808 key_ref_t
key_create_or_update(key_ref_t keyring_ref
,
810 const char *description
,
816 struct keyring_index_key index_key
= {
817 .description
= description
,
819 struct key_preparsed_payload prep
;
820 struct assoc_array_edit
*edit
= NULL
;
821 const struct cred
*cred
= current_cred();
822 struct key
*keyring
, *key
= NULL
;
825 struct key_restriction
*restrict_link
= NULL
;
827 /* look up the key type to see if it's one of the registered kernel
829 index_key
.type
= key_type_lookup(type
);
830 if (IS_ERR(index_key
.type
)) {
831 key_ref
= ERR_PTR(-ENODEV
);
835 key_ref
= ERR_PTR(-EINVAL
);
836 if (!index_key
.type
->instantiate
||
837 (!index_key
.description
&& !index_key
.type
->preparse
))
840 keyring
= key_ref_to_ptr(keyring_ref
);
844 if (!(flags
& KEY_ALLOC_BYPASS_RESTRICTION
))
845 restrict_link
= keyring
->restrict_link
;
847 key_ref
= ERR_PTR(-ENOTDIR
);
848 if (keyring
->type
!= &key_type_keyring
)
851 memset(&prep
, 0, sizeof(prep
));
854 prep
.quotalen
= index_key
.type
->def_datalen
;
855 prep
.expiry
= TIME64_MAX
;
856 if (index_key
.type
->preparse
) {
857 ret
= index_key
.type
->preparse(&prep
);
859 key_ref
= ERR_PTR(ret
);
860 goto error_free_prep
;
862 if (!index_key
.description
)
863 index_key
.description
= prep
.description
;
864 key_ref
= ERR_PTR(-EINVAL
);
865 if (!index_key
.description
)
866 goto error_free_prep
;
868 index_key
.desc_len
= strlen(index_key
.description
);
869 key_set_index_key(&index_key
);
871 ret
= __key_link_lock(keyring
, &index_key
);
873 key_ref
= ERR_PTR(ret
);
874 goto error_free_prep
;
877 ret
= __key_link_begin(keyring
, &index_key
, &edit
);
879 key_ref
= ERR_PTR(ret
);
883 if (restrict_link
&& restrict_link
->check
) {
884 ret
= restrict_link
->check(keyring
, index_key
.type
,
885 &prep
.payload
, restrict_link
->key
);
887 key_ref
= ERR_PTR(ret
);
892 /* if we're going to allocate a new key, we're going to have
893 * to modify the keyring */
894 ret
= key_permission(keyring_ref
, KEY_NEED_WRITE
);
896 key_ref
= ERR_PTR(ret
);
900 /* if it's possible to update this type of key, search for an existing
901 * key of the same type and description in the destination keyring and
902 * update that instead if possible
904 if (index_key
.type
->update
) {
905 key_ref
= find_key_to_update(keyring_ref
, &index_key
);
907 goto found_matching_key
;
910 /* if the client doesn't provide, decide on the permissions we want */
911 if (perm
== KEY_PERM_UNDEF
) {
912 perm
= KEY_POS_VIEW
| KEY_POS_SEARCH
| KEY_POS_LINK
| KEY_POS_SETATTR
;
913 perm
|= KEY_USR_VIEW
;
915 if (index_key
.type
->read
)
916 perm
|= KEY_POS_READ
;
918 if (index_key
.type
== &key_type_keyring
||
919 index_key
.type
->update
)
920 perm
|= KEY_POS_WRITE
;
923 /* allocate a new key */
924 key
= key_alloc(index_key
.type
, index_key
.description
,
925 cred
->fsuid
, cred
->fsgid
, cred
, perm
, flags
, NULL
);
927 key_ref
= ERR_CAST(key
);
931 /* instantiate it and link it into the target keyring */
932 ret
= __key_instantiate_and_link(key
, &prep
, keyring
, NULL
, &edit
);
935 key_ref
= ERR_PTR(ret
);
939 key_ref
= make_key_ref(key
, is_key_possessed(keyring_ref
));
942 __key_link_end(keyring
, &index_key
, edit
);
944 if (index_key
.type
->preparse
)
945 index_key
.type
->free_preparse(&prep
);
947 key_type_put(index_key
.type
);
952 /* we found a matching key, so we're going to try to update it
953 * - we can drop the locks first as we have the key pinned
955 __key_link_end(keyring
, &index_key
, edit
);
957 key
= key_ref_to_ptr(key_ref
);
958 if (test_bit(KEY_FLAG_USER_CONSTRUCT
, &key
->flags
)) {
959 ret
= wait_for_key_construction(key
, true);
961 key_ref_put(key_ref
);
962 key_ref
= ERR_PTR(ret
);
963 goto error_free_prep
;
967 key_ref
= __key_update(key_ref
, &prep
);
968 goto error_free_prep
;
970 EXPORT_SYMBOL(key_create_or_update
);
973 * key_update - Update a key's contents.
974 * @key_ref: The pointer (plus possession flag) to the key.
975 * @payload: The data to be used to update the key.
976 * @plen: The length of @payload.
978 * Attempt to update the contents of a key with the given payload data. The
979 * caller must be granted Write permission on the key. Negative keys can be
980 * instantiated by this method.
982 * Returns 0 on success, -EACCES if not permitted and -EOPNOTSUPP if the key
983 * type does not support updating. The key type may return other errors.
985 int key_update(key_ref_t key_ref
, const void *payload
, size_t plen
)
987 struct key_preparsed_payload prep
;
988 struct key
*key
= key_ref_to_ptr(key_ref
);
993 /* the key must be writable */
994 ret
= key_permission(key_ref
, KEY_NEED_WRITE
);
998 /* attempt to update it if supported */
999 if (!key
->type
->update
)
1002 memset(&prep
, 0, sizeof(prep
));
1003 prep
.data
= payload
;
1004 prep
.datalen
= plen
;
1005 prep
.quotalen
= key
->type
->def_datalen
;
1006 prep
.expiry
= TIME64_MAX
;
1007 if (key
->type
->preparse
) {
1008 ret
= key
->type
->preparse(&prep
);
1013 down_write(&key
->sem
);
1015 ret
= key
->type
->update(key
, &prep
);
1017 /* Updating a negative key positively instantiates it */
1018 mark_key_instantiated(key
, 0);
1020 up_write(&key
->sem
);
1023 if (key
->type
->preparse
)
1024 key
->type
->free_preparse(&prep
);
1027 EXPORT_SYMBOL(key_update
);
1030 * key_revoke - Revoke a key.
1031 * @key: The key to be revoked.
1033 * Mark a key as being revoked and ask the type to free up its resources. The
1034 * revocation timeout is set and the key and all its links will be
1035 * automatically garbage collected after key_gc_delay amount of time if they
1036 * are not manually dealt with first.
1038 void key_revoke(struct key
*key
)
1044 /* make sure no one's trying to change or use the key when we mark it
1045 * - we tell lockdep that we might nest because we might be revoking an
1046 * authorisation key whilst holding the sem on a key we've just
1049 down_write_nested(&key
->sem
, 1);
1050 if (!test_and_set_bit(KEY_FLAG_REVOKED
, &key
->flags
) &&
1052 key
->type
->revoke(key
);
1054 /* set the death time to no more than the expiry time */
1055 time
= ktime_get_real_seconds();
1056 if (key
->revoked_at
== 0 || key
->revoked_at
> time
) {
1057 key
->revoked_at
= time
;
1058 key_schedule_gc(key
->revoked_at
+ key_gc_delay
);
1061 up_write(&key
->sem
);
1063 EXPORT_SYMBOL(key_revoke
);
1066 * key_invalidate - Invalidate a key.
1067 * @key: The key to be invalidated.
1069 * Mark a key as being invalidated and have it cleaned up immediately. The key
1070 * is ignored by all searches and other operations from this point.
1072 void key_invalidate(struct key
*key
)
1074 kenter("%d", key_serial(key
));
1078 if (!test_bit(KEY_FLAG_INVALIDATED
, &key
->flags
)) {
1079 down_write_nested(&key
->sem
, 1);
1080 if (!test_and_set_bit(KEY_FLAG_INVALIDATED
, &key
->flags
))
1081 key_schedule_gc_links();
1082 up_write(&key
->sem
);
1085 EXPORT_SYMBOL(key_invalidate
);
1088 * generic_key_instantiate - Simple instantiation of a key from preparsed data
1089 * @key: The key to be instantiated
1090 * @prep: The preparsed data to load.
1092 * Instantiate a key from preparsed data. We assume we can just copy the data
1093 * in directly and clear the old pointers.
1095 * This can be pointed to directly by the key type instantiate op pointer.
1097 int generic_key_instantiate(struct key
*key
, struct key_preparsed_payload
*prep
)
1101 pr_devel("==>%s()\n", __func__
);
1103 ret
= key_payload_reserve(key
, prep
->quotalen
);
1105 rcu_assign_keypointer(key
, prep
->payload
.data
[0]);
1106 key
->payload
.data
[1] = prep
->payload
.data
[1];
1107 key
->payload
.data
[2] = prep
->payload
.data
[2];
1108 key
->payload
.data
[3] = prep
->payload
.data
[3];
1109 prep
->payload
.data
[0] = NULL
;
1110 prep
->payload
.data
[1] = NULL
;
1111 prep
->payload
.data
[2] = NULL
;
1112 prep
->payload
.data
[3] = NULL
;
1114 pr_devel("<==%s() = %d\n", __func__
, ret
);
1117 EXPORT_SYMBOL(generic_key_instantiate
);
1120 * register_key_type - Register a type of key.
1121 * @ktype: The new key type.
1123 * Register a new key type.
1125 * Returns 0 on success or -EEXIST if a type of this name already exists.
1127 int register_key_type(struct key_type
*ktype
)
1132 memset(&ktype
->lock_class
, 0, sizeof(ktype
->lock_class
));
1135 down_write(&key_types_sem
);
1137 /* disallow key types with the same name */
1138 list_for_each_entry(p
, &key_types_list
, link
) {
1139 if (strcmp(p
->name
, ktype
->name
) == 0)
1143 /* store the type */
1144 list_add(&ktype
->link
, &key_types_list
);
1146 pr_notice("Key type %s registered\n", ktype
->name
);
1150 up_write(&key_types_sem
);
1153 EXPORT_SYMBOL(register_key_type
);
1156 * unregister_key_type - Unregister a type of key.
1157 * @ktype: The key type.
1159 * Unregister a key type and mark all the extant keys of this type as dead.
1160 * Those keys of this type are then destroyed to get rid of their payloads and
1161 * they and their links will be garbage collected as soon as possible.
1163 void unregister_key_type(struct key_type
*ktype
)
1165 down_write(&key_types_sem
);
1166 list_del_init(&ktype
->link
);
1167 downgrade_write(&key_types_sem
);
1168 key_gc_keytype(ktype
);
1169 pr_notice("Key type %s unregistered\n", ktype
->name
);
1170 up_read(&key_types_sem
);
1172 EXPORT_SYMBOL(unregister_key_type
);
1175 * Initialise the key management state.
1177 void __init
key_init(void)
1179 /* allocate a slab in which we can store keys */
1180 key_jar
= kmem_cache_create("key_jar", sizeof(struct key
),
1181 0, SLAB_HWCACHE_ALIGN
|SLAB_PANIC
, NULL
);
1183 /* add the special key types */
1184 list_add_tail(&key_type_keyring
.link
, &key_types_list
);
1185 list_add_tail(&key_type_dead
.link
, &key_types_list
);
1186 list_add_tail(&key_type_user
.link
, &key_types_list
);
1187 list_add_tail(&key_type_logon
.link
, &key_types_list
);
1189 /* record the root user tracking */
1190 rb_link_node(&root_key_user
.node
,
1192 &key_user_tree
.rb_node
);
1194 rb_insert_color(&root_key_user
.node
,