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;
299 if (flags & KEY_ALLOC_BUILT_IN)
300 key->flags |= 1 << KEY_FLAG_BUILTIN;
303 key->magic = KEY_DEBUG_MAGIC;
306 /* let the security module know about the key */
307 ret = security_key_alloc(key, cred, flags);
311 /* publish the key by giving it a serial number */
312 atomic_inc(&user->nkeys);
313 key_alloc_serial(key);
319 kfree(key->description);
320 kmem_cache_free(key_jar, key);
321 if (!(flags & KEY_ALLOC_NOT_IN_QUOTA)) {
322 spin_lock(&user->lock);
324 user->qnbytes -= quotalen;
325 spin_unlock(&user->lock);
332 kmem_cache_free(key_jar, key);
334 if (!(flags & KEY_ALLOC_NOT_IN_QUOTA)) {
335 spin_lock(&user->lock);
337 user->qnbytes -= quotalen;
338 spin_unlock(&user->lock);
342 key = ERR_PTR(-ENOMEM);
346 spin_unlock(&user->lock);
348 key = ERR_PTR(-EDQUOT);
351 EXPORT_SYMBOL(key_alloc);
354 * key_payload_reserve - Adjust data quota reservation for the key's payload
355 * @key: The key to make the reservation for.
356 * @datalen: The amount of data payload the caller now wants.
358 * Adjust the amount of the owning user's key data quota that a key reserves.
359 * If the amount is increased, then -EDQUOT may be returned if there isn't
360 * enough free quota available.
362 * If successful, 0 is returned.
364 int key_payload_reserve(struct key *key, size_t datalen)
366 int delta = (int)datalen - key->datalen;
371 /* contemplate the quota adjustment */
372 if (delta != 0 && test_bit(KEY_FLAG_IN_QUOTA, &key->flags)) {
373 unsigned maxbytes = uid_eq(key->user->uid, GLOBAL_ROOT_UID) ?
374 key_quota_root_maxbytes : key_quota_maxbytes;
376 spin_lock(&key->user->lock);
379 (key->user->qnbytes + delta >= maxbytes ||
380 key->user->qnbytes + delta < key->user->qnbytes)) {
384 key->user->qnbytes += delta;
385 key->quotalen += delta;
387 spin_unlock(&key->user->lock);
390 /* change the recorded data length if that didn't generate an error */
392 key->datalen = datalen;
396 EXPORT_SYMBOL(key_payload_reserve);
399 * Instantiate a key and link it into the target keyring atomically. Must be
400 * called with the target keyring's semaphore writelocked. The target key's
401 * semaphore need not be locked as instantiation is serialised by
402 * key_construction_mutex.
404 static int __key_instantiate_and_link(struct key *key,
405 struct key_preparsed_payload *prep,
408 struct assoc_array_edit **_edit)
418 mutex_lock(&key_construction_mutex);
420 /* can't instantiate twice */
421 if (!test_bit(KEY_FLAG_INSTANTIATED, &key->flags)) {
422 /* instantiate the key */
423 ret = key->type->instantiate(key, prep);
426 /* mark the key as being instantiated */
427 atomic_inc(&key->user->nikeys);
428 set_bit(KEY_FLAG_INSTANTIATED, &key->flags);
430 if (test_and_clear_bit(KEY_FLAG_USER_CONSTRUCT, &key->flags))
433 /* and link it into the destination keyring */
435 if (test_bit(KEY_FLAG_KEEP, &keyring->flags))
436 set_bit(KEY_FLAG_KEEP, &key->flags);
438 __key_link(key, _edit);
441 /* disable the authorisation key */
445 if (prep->expiry != TIME_T_MAX) {
446 key->expiry = prep->expiry;
447 key_schedule_gc(prep->expiry + key_gc_delay);
452 mutex_unlock(&key_construction_mutex);
454 /* wake up anyone waiting for a key to be constructed */
456 wake_up_bit(&key->flags, KEY_FLAG_USER_CONSTRUCT);
462 * key_instantiate_and_link - Instantiate a key and link it into the keyring.
463 * @key: The key to instantiate.
464 * @data: The data to use to instantiate the keyring.
465 * @datalen: The length of @data.
466 * @keyring: Keyring to create a link in on success (or NULL).
467 * @authkey: The authorisation token permitting instantiation.
469 * Instantiate a key that's in the uninstantiated state using the provided data
470 * and, if successful, link it in to the destination keyring if one is
473 * If successful, 0 is returned, the authorisation token is revoked and anyone
474 * waiting for the key is woken up. If the key was already instantiated,
475 * -EBUSY will be returned.
477 int key_instantiate_and_link(struct key *key,
483 struct key_preparsed_payload prep;
484 struct assoc_array_edit *edit;
487 memset(&prep, 0, sizeof(prep));
489 prep.datalen = datalen;
490 prep.quotalen = key->type->def_datalen;
491 prep.expiry = TIME_T_MAX;
492 if (key->type->preparse) {
493 ret = key->type->preparse(&prep);
499 ret = __key_link_begin(keyring, &key->index_key, &edit);
504 ret = __key_instantiate_and_link(key, &prep, keyring, authkey, &edit);
507 __key_link_end(keyring, &key->index_key, edit);
510 if (key->type->preparse)
511 key->type->free_preparse(&prep);
515 EXPORT_SYMBOL(key_instantiate_and_link);
518 * key_reject_and_link - Negatively instantiate a key and link it into the keyring.
519 * @key: The key to instantiate.
520 * @timeout: The timeout on the negative key.
521 * @error: The error to return when the key is hit.
522 * @keyring: Keyring to create a link in on success (or NULL).
523 * @authkey: The authorisation token permitting instantiation.
525 * Negatively instantiate a key that's in the uninstantiated state and, if
526 * successful, set its timeout and stored error and link it in to the
527 * destination keyring if one is supplied. The key and any links to the key
528 * will be automatically garbage collected after the timeout expires.
530 * Negative keys are used to rate limit repeated request_key() calls by causing
531 * them to return the stored error code (typically ENOKEY) until the negative
534 * If successful, 0 is returned, the authorisation token is revoked and anyone
535 * waiting for the key is woken up. If the key was already instantiated,
536 * -EBUSY will be returned.
538 int key_reject_and_link(struct key *key,
544 struct assoc_array_edit *edit;
546 int ret, awaken, link_ret = 0;
555 link_ret = __key_link_begin(keyring, &key->index_key, &edit);
557 mutex_lock(&key_construction_mutex);
559 /* can't instantiate twice */
560 if (!test_bit(KEY_FLAG_INSTANTIATED, &key->flags)) {
561 /* mark the key as being negatively instantiated */
562 atomic_inc(&key->user->nikeys);
563 key->reject_error = -error;
565 set_bit(KEY_FLAG_NEGATIVE, &key->flags);
566 set_bit(KEY_FLAG_INSTANTIATED, &key->flags);
567 now = current_kernel_time();
568 key->expiry = now.tv_sec + timeout;
569 key_schedule_gc(key->expiry + key_gc_delay);
571 if (test_and_clear_bit(KEY_FLAG_USER_CONSTRUCT, &key->flags))
576 /* and link it into the destination keyring */
577 if (keyring && link_ret == 0)
578 __key_link(key, &edit);
580 /* disable the authorisation key */
585 mutex_unlock(&key_construction_mutex);
588 __key_link_end(keyring, &key->index_key, edit);
590 /* wake up anyone waiting for a key to be constructed */
592 wake_up_bit(&key->flags, KEY_FLAG_USER_CONSTRUCT);
594 return ret == 0 ? link_ret : ret;
596 EXPORT_SYMBOL(key_reject_and_link);
599 * key_put - Discard a reference to a key.
600 * @key: The key to discard a reference from.
602 * Discard a reference to a key, and when all the references are gone, we
603 * schedule the cleanup task to come and pull it out of the tree in process
604 * context at some later time.
606 void key_put(struct key *key)
611 if (atomic_dec_and_test(&key->usage))
612 schedule_work(&key_gc_work);
615 EXPORT_SYMBOL(key_put);
618 * Find a key by its serial number.
620 struct key *key_lookup(key_serial_t id)
625 spin_lock(&key_serial_lock);
627 /* search the tree for the specified key */
628 n = key_serial_tree.rb_node;
630 key = rb_entry(n, struct key, serial_node);
632 if (id < key->serial)
634 else if (id > key->serial)
641 key = ERR_PTR(-ENOKEY);
645 /* pretend it doesn't exist if it is awaiting deletion */
646 if (atomic_read(&key->usage) == 0)
649 /* this races with key_put(), but that doesn't matter since key_put()
650 * doesn't actually change the key
655 spin_unlock(&key_serial_lock);
660 * Find and lock the specified key type against removal.
662 * We return with the sem read-locked if successful. If the type wasn't
663 * available -ENOKEY is returned instead.
665 struct key_type *key_type_lookup(const char *type)
667 struct key_type *ktype;
669 down_read(&key_types_sem);
671 /* look up the key type to see if it's one of the registered kernel
673 list_for_each_entry(ktype, &key_types_list, link) {
674 if (strcmp(ktype->name, type) == 0)
675 goto found_kernel_type;
678 up_read(&key_types_sem);
679 ktype = ERR_PTR(-ENOKEY);
685 void key_set_timeout(struct key *key, unsigned timeout)
690 /* make the changes with the locks held to prevent races */
691 down_write(&key->sem);
694 now = current_kernel_time();
695 expiry = now.tv_sec + timeout;
698 key->expiry = expiry;
699 key_schedule_gc(key->expiry + key_gc_delay);
703 EXPORT_SYMBOL_GPL(key_set_timeout);
706 * Unlock a key type locked by key_type_lookup().
708 void key_type_put(struct key_type *ktype)
710 up_read(&key_types_sem);
714 * Attempt to update an existing key.
716 * The key is given to us with an incremented refcount that we need to discard
717 * if we get an error.
719 static inline key_ref_t __key_update(key_ref_t key_ref,
720 struct key_preparsed_payload *prep)
722 struct key *key = key_ref_to_ptr(key_ref);
725 /* need write permission on the key to update it */
726 ret = key_permission(key_ref, KEY_NEED_WRITE);
731 if (!key->type->update)
734 down_write(&key->sem);
736 ret = key->type->update(key, prep);
738 /* updating a negative key instantiates it */
739 clear_bit(KEY_FLAG_NEGATIVE, &key->flags);
750 key_ref = ERR_PTR(ret);
755 * key_create_or_update - Update or create and instantiate a key.
756 * @keyring_ref: A pointer to the destination keyring with possession flag.
757 * @type: The type of key.
758 * @description: The searchable description for the key.
759 * @payload: The data to use to instantiate or update the key.
760 * @plen: The length of @payload.
761 * @perm: The permissions mask for a new key.
762 * @flags: The quota flags for a new key.
764 * Search the destination keyring for a key of the same description and if one
765 * is found, update it, otherwise create and instantiate a new one and create a
766 * link to it from that keyring.
768 * If perm is KEY_PERM_UNDEF then an appropriate key permissions mask will be
771 * Returns a pointer to the new key if successful, -ENODEV if the key type
772 * wasn't available, -ENOTDIR if the keyring wasn't a keyring, -EACCES if the
773 * caller isn't permitted to modify the keyring or the LSM did not permit
774 * creation of the key.
776 * On success, the possession flag from the keyring ref will be tacked on to
777 * the key ref before it is returned.
779 key_ref_t key_create_or_update(key_ref_t keyring_ref,
781 const char *description,
787 struct keyring_index_key index_key = {
788 .description = description,
790 struct key_preparsed_payload prep;
791 struct assoc_array_edit *edit;
792 const struct cred *cred = current_cred();
793 struct key *keyring, *key = NULL;
797 /* look up the key type to see if it's one of the registered kernel
799 index_key.type = key_type_lookup(type);
800 if (IS_ERR(index_key.type)) {
801 key_ref = ERR_PTR(-ENODEV);
805 key_ref = ERR_PTR(-EINVAL);
806 if (!index_key.type->instantiate ||
807 (!index_key.description && !index_key.type->preparse))
810 keyring = key_ref_to_ptr(keyring_ref);
814 key_ref = ERR_PTR(-ENOTDIR);
815 if (keyring->type != &key_type_keyring)
818 memset(&prep, 0, sizeof(prep));
821 prep.quotalen = index_key.type->def_datalen;
822 prep.trusted = flags & KEY_ALLOC_TRUSTED;
823 prep.expiry = TIME_T_MAX;
824 if (index_key.type->preparse) {
825 ret = index_key.type->preparse(&prep);
827 key_ref = ERR_PTR(ret);
828 goto error_free_prep;
830 if (!index_key.description)
831 index_key.description = prep.description;
832 key_ref = ERR_PTR(-EINVAL);
833 if (!index_key.description)
834 goto error_free_prep;
836 index_key.desc_len = strlen(index_key.description);
838 key_ref = ERR_PTR(-EPERM);
839 if (!prep.trusted && test_bit(KEY_FLAG_TRUSTED_ONLY, &keyring->flags))
840 goto error_free_prep;
841 flags |= prep.trusted ? KEY_ALLOC_TRUSTED : 0;
843 ret = __key_link_begin(keyring, &index_key, &edit);
845 key_ref = ERR_PTR(ret);
846 goto error_free_prep;
849 /* if we're going to allocate a new key, we're going to have
850 * to modify the keyring */
851 ret = key_permission(keyring_ref, KEY_NEED_WRITE);
853 key_ref = ERR_PTR(ret);
857 /* if it's possible to update this type of key, search for an existing
858 * key of the same type and description in the destination keyring and
859 * update that instead if possible
861 if (index_key.type->update) {
862 key_ref = find_key_to_update(keyring_ref, &index_key);
864 goto found_matching_key;
867 /* if the client doesn't provide, decide on the permissions we want */
868 if (perm == KEY_PERM_UNDEF) {
869 perm = KEY_POS_VIEW | KEY_POS_SEARCH | KEY_POS_LINK | KEY_POS_SETATTR;
870 perm |= KEY_USR_VIEW;
872 if (index_key.type->read)
873 perm |= KEY_POS_READ;
875 if (index_key.type == &key_type_keyring ||
876 index_key.type->update)
877 perm |= KEY_POS_WRITE;
880 /* allocate a new key */
881 key = key_alloc(index_key.type, index_key.description,
882 cred->fsuid, cred->fsgid, cred, perm, flags);
884 key_ref = ERR_CAST(key);
888 /* instantiate it and link it into the target keyring */
889 ret = __key_instantiate_and_link(key, &prep, keyring, NULL, &edit);
892 key_ref = ERR_PTR(ret);
896 key_ref = make_key_ref(key, is_key_possessed(keyring_ref));
899 __key_link_end(keyring, &index_key, edit);
901 if (index_key.type->preparse)
902 index_key.type->free_preparse(&prep);
904 key_type_put(index_key.type);
909 /* we found a matching key, so we're going to try to update it
910 * - we can drop the locks first as we have the key pinned
912 __key_link_end(keyring, &index_key, edit);
914 key_ref = __key_update(key_ref, &prep);
915 goto error_free_prep;
917 EXPORT_SYMBOL(key_create_or_update);
920 * key_update - Update a key's contents.
921 * @key_ref: The pointer (plus possession flag) to the key.
922 * @payload: The data to be used to update the key.
923 * @plen: The length of @payload.
925 * Attempt to update the contents of a key with the given payload data. The
926 * caller must be granted Write permission on the key. Negative keys can be
927 * instantiated by this method.
929 * Returns 0 on success, -EACCES if not permitted and -EOPNOTSUPP if the key
930 * type does not support updating. The key type may return other errors.
932 int key_update(key_ref_t key_ref, const void *payload, size_t plen)
934 struct key_preparsed_payload prep;
935 struct key *key = key_ref_to_ptr(key_ref);
940 /* the key must be writable */
941 ret = key_permission(key_ref, KEY_NEED_WRITE);
945 /* attempt to update it if supported */
947 if (!key->type->update)
950 memset(&prep, 0, sizeof(prep));
953 prep.quotalen = key->type->def_datalen;
954 prep.expiry = TIME_T_MAX;
955 if (key->type->preparse) {
956 ret = key->type->preparse(&prep);
961 down_write(&key->sem);
963 ret = key->type->update(key, &prep);
965 /* updating a negative key instantiates it */
966 clear_bit(KEY_FLAG_NEGATIVE, &key->flags);
971 if (key->type->preparse)
972 key->type->free_preparse(&prep);
975 EXPORT_SYMBOL(key_update);
978 * key_revoke - Revoke a key.
979 * @key: The key to be revoked.
981 * Mark a key as being revoked and ask the type to free up its resources. The
982 * revocation timeout is set and the key and all its links will be
983 * automatically garbage collected after key_gc_delay amount of time if they
984 * are not manually dealt with first.
986 void key_revoke(struct key *key)
993 /* make sure no one's trying to change or use the key when we mark it
994 * - we tell lockdep that we might nest because we might be revoking an
995 * authorisation key whilst holding the sem on a key we've just
998 down_write_nested(&key->sem, 1);
999 if (!test_and_set_bit(KEY_FLAG_REVOKED, &key->flags) &&
1001 key->type->revoke(key);
1003 /* set the death time to no more than the expiry time */
1004 now = current_kernel_time();
1006 if (key->revoked_at == 0 || key->revoked_at > time) {
1007 key->revoked_at = time;
1008 key_schedule_gc(key->revoked_at + key_gc_delay);
1011 up_write(&key->sem);
1013 EXPORT_SYMBOL(key_revoke);
1016 * key_invalidate - Invalidate a key.
1017 * @key: The key to be invalidated.
1019 * Mark a key as being invalidated and have it cleaned up immediately. The key
1020 * is ignored by all searches and other operations from this point.
1022 void key_invalidate(struct key *key)
1024 kenter("%d", key_serial(key));
1028 if (!test_bit(KEY_FLAG_INVALIDATED, &key->flags)) {
1029 down_write_nested(&key->sem, 1);
1030 if (!test_and_set_bit(KEY_FLAG_INVALIDATED, &key->flags))
1031 key_schedule_gc_links();
1032 up_write(&key->sem);
1035 EXPORT_SYMBOL(key_invalidate);
1038 * generic_key_instantiate - Simple instantiation of a key from preparsed data
1039 * @key: The key to be instantiated
1040 * @prep: The preparsed data to load.
1042 * Instantiate a key from preparsed data. We assume we can just copy the data
1043 * in directly and clear the old pointers.
1045 * This can be pointed to directly by the key type instantiate op pointer.
1047 int generic_key_instantiate(struct key *key, struct key_preparsed_payload *prep)
1051 pr_devel("==>%s()\n", __func__);
1053 ret = key_payload_reserve(key, prep->quotalen);
1055 rcu_assign_keypointer(key, prep->payload.data[0]);
1056 key->payload.data[1] = prep->payload.data[1];
1057 key->payload.data[2] = prep->payload.data[2];
1058 key->payload.data[3] = prep->payload.data[3];
1059 prep->payload.data[0] = NULL;
1060 prep->payload.data[1] = NULL;
1061 prep->payload.data[2] = NULL;
1062 prep->payload.data[3] = NULL;
1064 pr_devel("<==%s() = %d\n", __func__, ret);
1067 EXPORT_SYMBOL(generic_key_instantiate);
1070 * register_key_type - Register a type of key.
1071 * @ktype: The new key type.
1073 * Register a new key type.
1075 * Returns 0 on success or -EEXIST if a type of this name already exists.
1077 int register_key_type(struct key_type *ktype)
1082 memset(&ktype->lock_class, 0, sizeof(ktype->lock_class));
1085 down_write(&key_types_sem);
1087 /* disallow key types with the same name */
1088 list_for_each_entry(p, &key_types_list, link) {
1089 if (strcmp(p->name, ktype->name) == 0)
1093 /* store the type */
1094 list_add(&ktype->link, &key_types_list);
1096 pr_notice("Key type %s registered\n", ktype->name);
1100 up_write(&key_types_sem);
1103 EXPORT_SYMBOL(register_key_type);
1106 * unregister_key_type - Unregister a type of key.
1107 * @ktype: The key type.
1109 * Unregister a key type and mark all the extant keys of this type as dead.
1110 * Those keys of this type are then destroyed to get rid of their payloads and
1111 * they and their links will be garbage collected as soon as possible.
1113 void unregister_key_type(struct key_type *ktype)
1115 down_write(&key_types_sem);
1116 list_del_init(&ktype->link);
1117 downgrade_write(&key_types_sem);
1118 key_gc_keytype(ktype);
1119 pr_notice("Key type %s unregistered\n", ktype->name);
1120 up_read(&key_types_sem);
1122 EXPORT_SYMBOL(unregister_key_type);
1125 * Initialise the key management state.
1127 void __init key_init(void)
1129 /* allocate a slab in which we can store keys */
1130 key_jar = kmem_cache_create("key_jar", sizeof(struct key),
1131 0, SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
1133 /* add the special key types */
1134 list_add_tail(&key_type_keyring.link, &key_types_list);
1135 list_add_tail(&key_type_dead.link, &key_types_list);
1136 list_add_tail(&key_type_user.link, &key_types_list);
1137 list_add_tail(&key_type_logon.link, &key_types_list);
1139 /* record the root user tracking */
1140 rb_link_node(&root_key_user.node,
1142 &key_user_tree.rb_node);
1144 rb_insert_color(&root_key_user.node,