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1/* Basic authentication token and access key management
2 *
3 * Copyright (C) 2004-2008 Red Hat, Inc. All Rights Reserved.
4 * Written by David Howells (dhowells@redhat.com)
5 *
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.
10 */
11
12#include <linux/module.h>
13#include <linux/init.h>
14#include <linux/poison.h>
15#include <linux/sched.h>
16#include <linux/slab.h>
17#include <linux/security.h>
18#include <linux/workqueue.h>
19#include <linux/random.h>
20#include <linux/err.h>
21#include "internal.h"
22
23struct kmem_cache *key_jar;
24struct rb_root key_serial_tree; /* tree of keys indexed by serial */
25DEFINE_SPINLOCK(key_serial_lock);
26
27struct rb_root key_user_tree; /* tree of quota records indexed by UID */
28DEFINE_SPINLOCK(key_user_lock);
29
30unsigned int key_quota_root_maxkeys = 200; /* root's key count quota */
31unsigned int key_quota_root_maxbytes = 20000; /* root's key space quota */
32unsigned int key_quota_maxkeys = 200; /* general key count quota */
33unsigned int key_quota_maxbytes = 20000; /* general key space quota */
34
35static LIST_HEAD(key_types_list);
36static DECLARE_RWSEM(key_types_sem);
37
38/* We serialise key instantiation and link */
39DEFINE_MUTEX(key_construction_mutex);
40
41#ifdef KEY_DEBUGGING
42void __key_check(const struct key *key)
43{
44 printk("__key_check: key %p {%08x} should be {%08x}\n",
45 key, key->magic, KEY_DEBUG_MAGIC);
46 BUG();
47}
48#endif
49
50/*
51 * Get the key quota record for a user, allocating a new record if one doesn't
52 * already exist.
53 */
54struct key_user *key_user_lookup(kuid_t uid)
55{
56 struct key_user *candidate = NULL, *user;
57 struct rb_node *parent = NULL;
58 struct rb_node **p;
59
60try_again:
61 p = &key_user_tree.rb_node;
62 spin_lock(&key_user_lock);
63
64 /* search the tree for a user record with a matching UID */
65 while (*p) {
66 parent = *p;
67 user = rb_entry(parent, struct key_user, node);
68
69 if (uid_lt(uid, user->uid))
70 p = &(*p)->rb_left;
71 else if (uid_gt(uid, user->uid))
72 p = &(*p)->rb_right;
73 else
74 goto found;
75 }
76
77 /* if we get here, we failed to find a match in the tree */
78 if (!candidate) {
79 /* allocate a candidate user record if we don't already have
80 * one */
81 spin_unlock(&key_user_lock);
82
83 user = NULL;
84 candidate = kmalloc(sizeof(struct key_user), GFP_KERNEL);
85 if (unlikely(!candidate))
86 goto out;
87
88 /* the allocation may have scheduled, so we need to repeat the
89 * search lest someone else added the record whilst we were
90 * asleep */
91 goto try_again;
92 }
93
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);
99 candidate->uid = uid;
100 candidate->qnkeys = 0;
101 candidate->qnbytes = 0;
102 spin_lock_init(&candidate->lock);
103 mutex_init(&candidate->cons_lock);
104
105 rb_link_node(&candidate->node, parent, p);
106 rb_insert_color(&candidate->node, &key_user_tree);
107 spin_unlock(&key_user_lock);
108 user = candidate;
109 goto out;
110
111 /* okay - we found a user record for this UID */
112found:
113 atomic_inc(&user->usage);
114 spin_unlock(&key_user_lock);
115 kfree(candidate);
116out:
117 return user;
118}
119
120/*
121 * Dispose of a user structure
122 */
123void key_user_put(struct key_user *user)
124{
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);
128
129 kfree(user);
130 }
131}
132
133/*
134 * Allocate a serial number for a key. These are assigned randomly to avoid
135 * security issues through covert channel problems.
136 */
137static inline void key_alloc_serial(struct key *key)
138{
139 struct rb_node *parent, **p;
140 struct key *xkey;
141
142 /* propose a random serial number and look for a hole for it in the
143 * serial number tree */
144 do {
145 get_random_bytes(&key->serial, sizeof(key->serial));
146
147 key->serial >>= 1; /* negative numbers are not permitted */
148 } while (key->serial < 3);
149
150 spin_lock(&key_serial_lock);
151
152attempt_insertion:
153 parent = NULL;
154 p = &key_serial_tree.rb_node;
155
156 while (*p) {
157 parent = *p;
158 xkey = rb_entry(parent, struct key, serial_node);
159
160 if (key->serial < xkey->serial)
161 p = &(*p)->rb_left;
162 else if (key->serial > xkey->serial)
163 p = &(*p)->rb_right;
164 else
165 goto serial_exists;
166 }
167
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);
171
172 spin_unlock(&key_serial_lock);
173 return;
174
175 /* we found a key with the proposed serial number - walk the tree from
176 * that point looking for the next unused serial number */
177serial_exists:
178 for (;;) {
179 key->serial++;
180 if (key->serial < 3) {
181 key->serial = 3;
182 goto attempt_insertion;
183 }
184
185 parent = rb_next(parent);
186 if (!parent)
187 goto attempt_insertion;
188
189 xkey = rb_entry(parent, struct key, serial_node);
190 if (key->serial < xkey->serial)
191 goto attempt_insertion;
192 }
193}
194
195/**
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 *
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.
208 *
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.
213 *
214 * The LSM security modules can prevent a key being created, in which case
215 * -EACCES will be returned.
216 *
217 * Returns a pointer to the new key if successful and an error code otherwise.
218 *
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.
223 */
224struct 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{
228 struct key_user *user = NULL;
229 struct key *key;
230 size_t desclen, quotalen;
231 int ret;
232
233 key = ERR_PTR(-EINVAL);
234 if (!desc || !*desc)
235 goto error;
236
237 if (type->vet_description) {
238 ret = type->vet_description(desc);
239 if (ret < 0) {
240 key = ERR_PTR(ret);
241 goto error;
242 }
243 }
244
245 desclen = strlen(desc);
246 quotalen = desclen + 1 + type->def_datalen;
247
248 /* get hold of the key tracking for this user */
249 user = key_user_lookup(uid);
250 if (!user)
251 goto no_memory_1;
252
253 /* check that the user's quota permits allocation of another key and
254 * its description */
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;
260
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)
266 goto no_quota;
267 }
268
269 user->qnkeys++;
270 user->qnbytes += quotalen;
271 spin_unlock(&user->lock);
272 }
273
274 /* allocate and initialise the key and its description */
275 key = kmem_cache_zalloc(key_jar, GFP_KERNEL);
276 if (!key)
277 goto no_memory_2;
278
279 if (desc) {
280 key->index_key.desc_len = desclen;
281 key->index_key.description = kmemdup(desc, desclen + 1, GFP_KERNEL);
282 if (!key->description)
283 goto no_memory_3;
284 }
285
286 atomic_set(&key->usage, 1);
287 init_rwsem(&key->sem);
288 lockdep_set_class(&key->sem, &type->lock_class);
289 key->index_key.type = type;
290 key->user = user;
291 key->quotalen = quotalen;
292 key->datalen = type->def_datalen;
293 key->uid = uid;
294 key->gid = gid;
295 key->perm = perm;
296
297 if (!(flags & KEY_ALLOC_NOT_IN_QUOTA))
298 key->flags |= 1 << KEY_FLAG_IN_QUOTA;
299 if (flags & KEY_ALLOC_TRUSTED)
300 key->flags |= 1 << KEY_FLAG_TRUSTED;
301
302#ifdef KEY_DEBUGGING
303 key->magic = KEY_DEBUG_MAGIC;
304#endif
305
306 /* let the security module know about the key */
307 ret = security_key_alloc(key, cred, flags);
308 if (ret < 0)
309 goto security_error;
310
311 /* publish the key by giving it a serial number */
312 atomic_inc(&user->nkeys);
313 key_alloc_serial(key);
314
315error:
316 return key;
317
318security_error:
319 kfree(key->description);
320 kmem_cache_free(key_jar, key);
321 if (!(flags & KEY_ALLOC_NOT_IN_QUOTA)) {
322 spin_lock(&user->lock);
323 user->qnkeys--;
324 user->qnbytes -= quotalen;
325 spin_unlock(&user->lock);
326 }
327 key_user_put(user);
328 key = ERR_PTR(ret);
329 goto error;
330
331no_memory_3:
332 kmem_cache_free(key_jar, key);
333no_memory_2:
334 if (!(flags & KEY_ALLOC_NOT_IN_QUOTA)) {
335 spin_lock(&user->lock);
336 user->qnkeys--;
337 user->qnbytes -= quotalen;
338 spin_unlock(&user->lock);
339 }
340 key_user_put(user);
341no_memory_1:
342 key = ERR_PTR(-ENOMEM);
343 goto error;
344
345no_quota:
346 spin_unlock(&user->lock);
347 key_user_put(user);
348 key = ERR_PTR(-EDQUOT);
349 goto error;
350}
351EXPORT_SYMBOL(key_alloc);
352
353/**
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.
357 *
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.
361 *
362 * If successful, 0 is returned.
363 */
364int key_payload_reserve(struct key *key, size_t datalen)
365{
366 int delta = (int)datalen - key->datalen;
367 int ret = 0;
368
369 key_check(key);
370
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;
375
376 spin_lock(&key->user->lock);
377
378 if (delta > 0 &&
379 (key->user->qnbytes + delta >= maxbytes ||
380 key->user->qnbytes + delta < key->user->qnbytes)) {
381 ret = -EDQUOT;
382 }
383 else {
384 key->user->qnbytes += delta;
385 key->quotalen += delta;
386 }
387 spin_unlock(&key->user->lock);
388 }
389
390 /* change the recorded data length if that didn't generate an error */
391 if (ret == 0)
392 key->datalen = datalen;
393
394 return ret;
395}
396EXPORT_SYMBOL(key_payload_reserve);
397
398/*
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.
403 */
404static int __key_instantiate_and_link(struct key *key,
405 struct key_preparsed_payload *prep,
406 struct key *keyring,
407 struct key *authkey,
408 struct assoc_array_edit **_edit)
409{
410 int ret, awaken;
411
412 key_check(key);
413 key_check(keyring);
414
415 awaken = 0;
416 ret = -EBUSY;
417
418 mutex_lock(&key_construction_mutex);
419
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);
424
425 if (ret == 0) {
426 /* mark the key as being instantiated */
427 atomic_inc(&key->user->nikeys);
428 set_bit(KEY_FLAG_INSTANTIATED, &key->flags);
429
430 if (test_and_clear_bit(KEY_FLAG_USER_CONSTRUCT, &key->flags))
431 awaken = 1;
432
433 /* and link it into the destination keyring */
434 if (keyring)
435 __key_link(key, _edit);
436
437 /* disable the authorisation key */
438 if (authkey)
439 key_revoke(authkey);
440 }
441 }
442
443 mutex_unlock(&key_construction_mutex);
444
445 /* wake up anyone waiting for a key to be constructed */
446 if (awaken)
447 wake_up_bit(&key->flags, KEY_FLAG_USER_CONSTRUCT);
448
449 return ret;
450}
451
452/**
453 * key_instantiate_and_link - Instantiate a key and link it into the keyring.
454 * @key: The key to instantiate.
455 * @data: The data to use to instantiate the keyring.
456 * @datalen: The length of @data.
457 * @keyring: Keyring to create a link in on success (or NULL).
458 * @authkey: The authorisation token permitting instantiation.
459 *
460 * Instantiate a key that's in the uninstantiated state using the provided data
461 * and, if successful, link it in to the destination keyring if one is
462 * supplied.
463 *
464 * If successful, 0 is returned, the authorisation token is revoked and anyone
465 * waiting for the key is woken up. If the key was already instantiated,
466 * -EBUSY will be returned.
467 */
468int key_instantiate_and_link(struct key *key,
469 const void *data,
470 size_t datalen,
471 struct key *keyring,
472 struct key *authkey)
473{
474 struct key_preparsed_payload prep;
475 struct assoc_array_edit *edit;
476 int ret;
477
478 memset(&prep, 0, sizeof(prep));
479 prep.data = data;
480 prep.datalen = datalen;
481 prep.quotalen = key->type->def_datalen;
482 if (key->type->preparse) {
483 ret = key->type->preparse(&prep);
484 if (ret < 0)
485 goto error;
486 }
487
488 if (keyring) {
489 ret = __key_link_begin(keyring, &key->index_key, &edit);
490 if (ret < 0)
491 goto error_free_preparse;
492 }
493
494 ret = __key_instantiate_and_link(key, &prep, keyring, authkey, &edit);
495
496 if (keyring)
497 __key_link_end(keyring, &key->index_key, edit);
498
499error_free_preparse:
500 if (key->type->preparse)
501 key->type->free_preparse(&prep);
502error:
503 return ret;
504}
505
506EXPORT_SYMBOL(key_instantiate_and_link);
507
508/**
509 * key_reject_and_link - Negatively instantiate a key and link it into the keyring.
510 * @key: The key to instantiate.
511 * @timeout: The timeout on the negative key.
512 * @error: The error to return when the key is hit.
513 * @keyring: Keyring to create a link in on success (or NULL).
514 * @authkey: The authorisation token permitting instantiation.
515 *
516 * Negatively instantiate a key that's in the uninstantiated state and, if
517 * successful, set its timeout and stored error and link it in to the
518 * destination keyring if one is supplied. The key and any links to the key
519 * will be automatically garbage collected after the timeout expires.
520 *
521 * Negative keys are used to rate limit repeated request_key() calls by causing
522 * them to return the stored error code (typically ENOKEY) until the negative
523 * key expires.
524 *
525 * If successful, 0 is returned, the authorisation token is revoked and anyone
526 * waiting for the key is woken up. If the key was already instantiated,
527 * -EBUSY will be returned.
528 */
529int key_reject_and_link(struct key *key,
530 unsigned timeout,
531 unsigned error,
532 struct key *keyring,
533 struct key *authkey)
534{
535 struct assoc_array_edit *edit;
536 struct timespec now;
537 int ret, awaken, link_ret = 0;
538
539 key_check(key);
540 key_check(keyring);
541
542 awaken = 0;
543 ret = -EBUSY;
544
545 if (keyring)
546 link_ret = __key_link_begin(keyring, &key->index_key, &edit);
547
548 mutex_lock(&key_construction_mutex);
549
550 /* can't instantiate twice */
551 if (!test_bit(KEY_FLAG_INSTANTIATED, &key->flags)) {
552 /* mark the key as being negatively instantiated */
553 atomic_inc(&key->user->nikeys);
554 key->type_data.reject_error = -error;
555 smp_wmb();
556 set_bit(KEY_FLAG_NEGATIVE, &key->flags);
557 set_bit(KEY_FLAG_INSTANTIATED, &key->flags);
558 now = current_kernel_time();
559 key->expiry = now.tv_sec + timeout;
560 key_schedule_gc(key->expiry + key_gc_delay);
561
562 if (test_and_clear_bit(KEY_FLAG_USER_CONSTRUCT, &key->flags))
563 awaken = 1;
564
565 ret = 0;
566
567 /* and link it into the destination keyring */
568 if (keyring && link_ret == 0)
569 __key_link(key, &edit);
570
571 /* disable the authorisation key */
572 if (authkey)
573 key_revoke(authkey);
574 }
575
576 mutex_unlock(&key_construction_mutex);
577
578 if (keyring)
579 __key_link_end(keyring, &key->index_key, edit);
580
581 /* wake up anyone waiting for a key to be constructed */
582 if (awaken)
583 wake_up_bit(&key->flags, KEY_FLAG_USER_CONSTRUCT);
584
585 return ret == 0 ? link_ret : ret;
586}
587EXPORT_SYMBOL(key_reject_and_link);
588
589/**
590 * key_put - Discard a reference to a key.
591 * @key: The key to discard a reference from.
592 *
593 * Discard a reference to a key, and when all the references are gone, we
594 * schedule the cleanup task to come and pull it out of the tree in process
595 * context at some later time.
596 */
597void key_put(struct key *key)
598{
599 if (key) {
600 key_check(key);
601
602 if (atomic_dec_and_test(&key->usage))
603 schedule_work(&key_gc_work);
604 }
605}
606EXPORT_SYMBOL(key_put);
607
608/*
609 * Find a key by its serial number.
610 */
611struct key *key_lookup(key_serial_t id)
612{
613 struct rb_node *n;
614 struct key *key;
615
616 spin_lock(&key_serial_lock);
617
618 /* search the tree for the specified key */
619 n = key_serial_tree.rb_node;
620 while (n) {
621 key = rb_entry(n, struct key, serial_node);
622
623 if (id < key->serial)
624 n = n->rb_left;
625 else if (id > key->serial)
626 n = n->rb_right;
627 else
628 goto found;
629 }
630
631not_found:
632 key = ERR_PTR(-ENOKEY);
633 goto error;
634
635found:
636 /* pretend it doesn't exist if it is awaiting deletion */
637 if (atomic_read(&key->usage) == 0)
638 goto not_found;
639
640 /* this races with key_put(), but that doesn't matter since key_put()
641 * doesn't actually change the key
642 */
643 __key_get(key);
644
645error:
646 spin_unlock(&key_serial_lock);
647 return key;
648}
649
650/*
651 * Find and lock the specified key type against removal.
652 *
653 * We return with the sem read-locked if successful. If the type wasn't
654 * available -ENOKEY is returned instead.
655 */
656struct key_type *key_type_lookup(const char *type)
657{
658 struct key_type *ktype;
659
660 down_read(&key_types_sem);
661
662 /* look up the key type to see if it's one of the registered kernel
663 * types */
664 list_for_each_entry(ktype, &key_types_list, link) {
665 if (strcmp(ktype->name, type) == 0)
666 goto found_kernel_type;
667 }
668
669 up_read(&key_types_sem);
670 ktype = ERR_PTR(-ENOKEY);
671
672found_kernel_type:
673 return ktype;
674}
675
676void key_set_timeout(struct key *key, unsigned timeout)
677{
678 struct timespec now;
679 time_t expiry = 0;
680
681 /* make the changes with the locks held to prevent races */
682 down_write(&key->sem);
683
684 if (timeout > 0) {
685 now = current_kernel_time();
686 expiry = now.tv_sec + timeout;
687 }
688
689 key->expiry = expiry;
690 key_schedule_gc(key->expiry + key_gc_delay);
691
692 up_write(&key->sem);
693}
694EXPORT_SYMBOL_GPL(key_set_timeout);
695
696/*
697 * Unlock a key type locked by key_type_lookup().
698 */
699void key_type_put(struct key_type *ktype)
700{
701 up_read(&key_types_sem);
702}
703
704/*
705 * Attempt to update an existing key.
706 *
707 * The key is given to us with an incremented refcount that we need to discard
708 * if we get an error.
709 */
710static inline key_ref_t __key_update(key_ref_t key_ref,
711 struct key_preparsed_payload *prep)
712{
713 struct key *key = key_ref_to_ptr(key_ref);
714 int ret;
715
716 /* need write permission on the key to update it */
717 ret = key_permission(key_ref, KEY_WRITE);
718 if (ret < 0)
719 goto error;
720
721 ret = -EEXIST;
722 if (!key->type->update)
723 goto error;
724
725 down_write(&key->sem);
726
727 ret = key->type->update(key, prep);
728 if (ret == 0)
729 /* updating a negative key instantiates it */
730 clear_bit(KEY_FLAG_NEGATIVE, &key->flags);
731
732 up_write(&key->sem);
733
734 if (ret < 0)
735 goto error;
736out:
737 return key_ref;
738
739error:
740 key_put(key);
741 key_ref = ERR_PTR(ret);
742 goto out;
743}
744
745/**
746 * key_create_or_update - Update or create and instantiate a key.
747 * @keyring_ref: A pointer to the destination keyring with possession flag.
748 * @type: The type of key.
749 * @description: The searchable description for the key.
750 * @payload: The data to use to instantiate or update the key.
751 * @plen: The length of @payload.
752 * @perm: The permissions mask for a new key.
753 * @flags: The quota flags for a new key.
754 *
755 * Search the destination keyring for a key of the same description and if one
756 * is found, update it, otherwise create and instantiate a new one and create a
757 * link to it from that keyring.
758 *
759 * If perm is KEY_PERM_UNDEF then an appropriate key permissions mask will be
760 * concocted.
761 *
762 * Returns a pointer to the new key if successful, -ENODEV if the key type
763 * wasn't available, -ENOTDIR if the keyring wasn't a keyring, -EACCES if the
764 * caller isn't permitted to modify the keyring or the LSM did not permit
765 * creation of the key.
766 *
767 * On success, the possession flag from the keyring ref will be tacked on to
768 * the key ref before it is returned.
769 */
770key_ref_t key_create_or_update(key_ref_t keyring_ref,
771 const char *type,
772 const char *description,
773 const void *payload,
774 size_t plen,
775 key_perm_t perm,
776 unsigned long flags)
777{
778 struct keyring_index_key index_key = {
779 .description = description,
780 };
781 struct key_preparsed_payload prep;
782 struct assoc_array_edit *edit;
783 const struct cred *cred = current_cred();
784 struct key *keyring, *key = NULL;
785 key_ref_t key_ref;
786 int ret;
787
788 /* look up the key type to see if it's one of the registered kernel
789 * types */
790 index_key.type = key_type_lookup(type);
791 if (IS_ERR(index_key.type)) {
792 key_ref = ERR_PTR(-ENODEV);
793 goto error;
794 }
795
796 key_ref = ERR_PTR(-EINVAL);
797 if (!index_key.type->match || !index_key.type->instantiate ||
798 (!index_key.description && !index_key.type->preparse))
799 goto error_put_type;
800
801 keyring = key_ref_to_ptr(keyring_ref);
802
803 key_check(keyring);
804
805 key_ref = ERR_PTR(-ENOTDIR);
806 if (keyring->type != &key_type_keyring)
807 goto error_put_type;
808
809 memset(&prep, 0, sizeof(prep));
810 prep.data = payload;
811 prep.datalen = plen;
812 prep.quotalen = index_key.type->def_datalen;
813 prep.trusted = flags & KEY_ALLOC_TRUSTED;
814 if (index_key.type->preparse) {
815 ret = index_key.type->preparse(&prep);
816 if (ret < 0) {
817 key_ref = ERR_PTR(ret);
818 goto error_put_type;
819 }
820 if (!index_key.description)
821 index_key.description = prep.description;
822 key_ref = ERR_PTR(-EINVAL);
823 if (!index_key.description)
824 goto error_free_prep;
825 }
826 index_key.desc_len = strlen(index_key.description);
827
828 key_ref = ERR_PTR(-EPERM);
829 if (!prep.trusted && test_bit(KEY_FLAG_TRUSTED_ONLY, &keyring->flags))
830 goto error_free_prep;
831 flags |= prep.trusted ? KEY_ALLOC_TRUSTED : 0;
832
833 ret = __key_link_begin(keyring, &index_key, &edit);
834 if (ret < 0) {
835 key_ref = ERR_PTR(ret);
836 goto error_free_prep;
837 }
838
839 /* if we're going to allocate a new key, we're going to have
840 * to modify the keyring */
841 ret = key_permission(keyring_ref, KEY_WRITE);
842 if (ret < 0) {
843 key_ref = ERR_PTR(ret);
844 goto error_link_end;
845 }
846
847 /* if it's possible to update this type of key, search for an existing
848 * key of the same type and description in the destination keyring and
849 * update that instead if possible
850 */
851 if (index_key.type->update) {
852 key_ref = find_key_to_update(keyring_ref, &index_key);
853 if (key_ref)
854 goto found_matching_key;
855 }
856
857 /* if the client doesn't provide, decide on the permissions we want */
858 if (perm == KEY_PERM_UNDEF) {
859 perm = KEY_POS_VIEW | KEY_POS_SEARCH | KEY_POS_LINK | KEY_POS_SETATTR;
860 perm |= KEY_USR_VIEW;
861
862 if (index_key.type->read)
863 perm |= KEY_POS_READ;
864
865 if (index_key.type == &key_type_keyring ||
866 index_key.type->update)
867 perm |= KEY_POS_WRITE;
868 }
869
870 /* allocate a new key */
871 key = key_alloc(index_key.type, index_key.description,
872 cred->fsuid, cred->fsgid, cred, perm, flags);
873 if (IS_ERR(key)) {
874 key_ref = ERR_CAST(key);
875 goto error_link_end;
876 }
877
878 /* instantiate it and link it into the target keyring */
879 ret = __key_instantiate_and_link(key, &prep, keyring, NULL, &edit);
880 if (ret < 0) {
881 key_put(key);
882 key_ref = ERR_PTR(ret);
883 goto error_link_end;
884 }
885
886 key_ref = make_key_ref(key, is_key_possessed(keyring_ref));
887
888error_link_end:
889 __key_link_end(keyring, &index_key, edit);
890error_free_prep:
891 if (index_key.type->preparse)
892 index_key.type->free_preparse(&prep);
893error_put_type:
894 key_type_put(index_key.type);
895error:
896 return key_ref;
897
898 found_matching_key:
899 /* we found a matching key, so we're going to try to update it
900 * - we can drop the locks first as we have the key pinned
901 */
902 __key_link_end(keyring, &index_key, edit);
903
904 key_ref = __key_update(key_ref, &prep);
905 goto error_free_prep;
906}
907EXPORT_SYMBOL(key_create_or_update);
908
909/**
910 * key_update - Update a key's contents.
911 * @key_ref: The pointer (plus possession flag) to the key.
912 * @payload: The data to be used to update the key.
913 * @plen: The length of @payload.
914 *
915 * Attempt to update the contents of a key with the given payload data. The
916 * caller must be granted Write permission on the key. Negative keys can be
917 * instantiated by this method.
918 *
919 * Returns 0 on success, -EACCES if not permitted and -EOPNOTSUPP if the key
920 * type does not support updating. The key type may return other errors.
921 */
922int key_update(key_ref_t key_ref, const void *payload, size_t plen)
923{
924 struct key_preparsed_payload prep;
925 struct key *key = key_ref_to_ptr(key_ref);
926 int ret;
927
928 key_check(key);
929
930 /* the key must be writable */
931 ret = key_permission(key_ref, KEY_WRITE);
932 if (ret < 0)
933 goto error;
934
935 /* attempt to update it if supported */
936 ret = -EOPNOTSUPP;
937 if (!key->type->update)
938 goto error;
939
940 memset(&prep, 0, sizeof(prep));
941 prep.data = payload;
942 prep.datalen = plen;
943 prep.quotalen = key->type->def_datalen;
944 if (key->type->preparse) {
945 ret = key->type->preparse(&prep);
946 if (ret < 0)
947 goto error;
948 }
949
950 down_write(&key->sem);
951
952 ret = key->type->update(key, &prep);
953 if (ret == 0)
954 /* updating a negative key instantiates it */
955 clear_bit(KEY_FLAG_NEGATIVE, &key->flags);
956
957 up_write(&key->sem);
958
959 if (key->type->preparse)
960 key->type->free_preparse(&prep);
961error:
962 return ret;
963}
964EXPORT_SYMBOL(key_update);
965
966/**
967 * key_revoke - Revoke a key.
968 * @key: The key to be revoked.
969 *
970 * Mark a key as being revoked and ask the type to free up its resources. The
971 * revocation timeout is set and the key and all its links will be
972 * automatically garbage collected after key_gc_delay amount of time if they
973 * are not manually dealt with first.
974 */
975void key_revoke(struct key *key)
976{
977 struct timespec now;
978 time_t time;
979
980 key_check(key);
981
982 /* make sure no one's trying to change or use the key when we mark it
983 * - we tell lockdep that we might nest because we might be revoking an
984 * authorisation key whilst holding the sem on a key we've just
985 * instantiated
986 */
987 down_write_nested(&key->sem, 1);
988 if (!test_and_set_bit(KEY_FLAG_REVOKED, &key->flags) &&
989 key->type->revoke)
990 key->type->revoke(key);
991
992 /* set the death time to no more than the expiry time */
993 now = current_kernel_time();
994 time = now.tv_sec;
995 if (key->revoked_at == 0 || key->revoked_at > time) {
996 key->revoked_at = time;
997 key_schedule_gc(key->revoked_at + key_gc_delay);
998 }
999
1000 up_write(&key->sem);
1001}
1002EXPORT_SYMBOL(key_revoke);
1003
1004/**
1005 * key_invalidate - Invalidate a key.
1006 * @key: The key to be invalidated.
1007 *
1008 * Mark a key as being invalidated and have it cleaned up immediately. The key
1009 * is ignored by all searches and other operations from this point.
1010 */
1011void key_invalidate(struct key *key)
1012{
1013 kenter("%d", key_serial(key));
1014
1015 key_check(key);
1016
1017 if (!test_bit(KEY_FLAG_INVALIDATED, &key->flags)) {
1018 down_write_nested(&key->sem, 1);
1019 if (!test_and_set_bit(KEY_FLAG_INVALIDATED, &key->flags))
1020 key_schedule_gc_links();
1021 up_write(&key->sem);
1022 }
1023}
1024EXPORT_SYMBOL(key_invalidate);
1025
1026/**
1027 * register_key_type - Register a type of key.
1028 * @ktype: The new key type.
1029 *
1030 * Register a new key type.
1031 *
1032 * Returns 0 on success or -EEXIST if a type of this name already exists.
1033 */
1034int register_key_type(struct key_type *ktype)
1035{
1036 struct key_type *p;
1037 int ret;
1038
1039 memset(&ktype->lock_class, 0, sizeof(ktype->lock_class));
1040
1041 ret = -EEXIST;
1042 down_write(&key_types_sem);
1043
1044 /* disallow key types with the same name */
1045 list_for_each_entry(p, &key_types_list, link) {
1046 if (strcmp(p->name, ktype->name) == 0)
1047 goto out;
1048 }
1049
1050 /* store the type */
1051 list_add(&ktype->link, &key_types_list);
1052
1053 pr_notice("Key type %s registered\n", ktype->name);
1054 ret = 0;
1055
1056out:
1057 up_write(&key_types_sem);
1058 return ret;
1059}
1060EXPORT_SYMBOL(register_key_type);
1061
1062/**
1063 * unregister_key_type - Unregister a type of key.
1064 * @ktype: The key type.
1065 *
1066 * Unregister a key type and mark all the extant keys of this type as dead.
1067 * Those keys of this type are then destroyed to get rid of their payloads and
1068 * they and their links will be garbage collected as soon as possible.
1069 */
1070void unregister_key_type(struct key_type *ktype)
1071{
1072 down_write(&key_types_sem);
1073 list_del_init(&ktype->link);
1074 downgrade_write(&key_types_sem);
1075 key_gc_keytype(ktype);
1076 pr_notice("Key type %s unregistered\n", ktype->name);
1077 up_read(&key_types_sem);
1078}
1079EXPORT_SYMBOL(unregister_key_type);
1080
1081/*
1082 * Initialise the key management state.
1083 */
1084void __init key_init(void)
1085{
1086 /* allocate a slab in which we can store keys */
1087 key_jar = kmem_cache_create("key_jar", sizeof(struct key),
1088 0, SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
1089
1090 /* add the special key types */
1091 list_add_tail(&key_type_keyring.link, &key_types_list);
1092 list_add_tail(&key_type_dead.link, &key_types_list);
1093 list_add_tail(&key_type_user.link, &key_types_list);
1094 list_add_tail(&key_type_logon.link, &key_types_list);
1095
1096 /* record the root user tracking */
1097 rb_link_node(&root_key_user.node,
1098 NULL,
1099 &key_user_tree.rb_node);
1100
1101 rb_insert_color(&root_key_user.node,
1102 &key_user_tree);
1103}
1// SPDX-License-Identifier: GPL-2.0-or-later
2/* Basic authentication token and access key management
3 *
4 * Copyright (C) 2004-2008 Red Hat, Inc. All Rights Reserved.
5 * Written by David Howells (dhowells@redhat.com)
6 */
7
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>
17#include "internal.h"
18
19struct kmem_cache *key_jar;
20struct rb_root key_serial_tree; /* tree of keys indexed by serial */
21DEFINE_SPINLOCK(key_serial_lock);
22
23struct rb_root key_user_tree; /* tree of quota records indexed by UID */
24DEFINE_SPINLOCK(key_user_lock);
25
26unsigned int key_quota_root_maxkeys = 1000000; /* root's key count quota */
27unsigned int key_quota_root_maxbytes = 25000000; /* root's key space quota */
28unsigned int key_quota_maxkeys = 200; /* general key count quota */
29unsigned int key_quota_maxbytes = 20000; /* general key space quota */
30
31static LIST_HEAD(key_types_list);
32static DECLARE_RWSEM(key_types_sem);
33
34/* We serialise key instantiation and link */
35DEFINE_MUTEX(key_construction_mutex);
36
37#ifdef KEY_DEBUGGING
38void __key_check(const struct key *key)
39{
40 printk("__key_check: key %p {%08x} should be {%08x}\n",
41 key, key->magic, KEY_DEBUG_MAGIC);
42 BUG();
43}
44#endif
45
46/*
47 * Get the key quota record for a user, allocating a new record if one doesn't
48 * already exist.
49 */
50struct key_user *key_user_lookup(kuid_t uid)
51{
52 struct key_user *candidate = NULL, *user;
53 struct rb_node *parent, **p;
54
55try_again:
56 parent = NULL;
57 p = &key_user_tree.rb_node;
58 spin_lock(&key_user_lock);
59
60 /* search the tree for a user record with a matching UID */
61 while (*p) {
62 parent = *p;
63 user = rb_entry(parent, struct key_user, node);
64
65 if (uid_lt(uid, user->uid))
66 p = &(*p)->rb_left;
67 else if (uid_gt(uid, user->uid))
68 p = &(*p)->rb_right;
69 else
70 goto found;
71 }
72
73 /* if we get here, we failed to find a match in the tree */
74 if (!candidate) {
75 /* allocate a candidate user record if we don't already have
76 * one */
77 spin_unlock(&key_user_lock);
78
79 user = NULL;
80 candidate = kmalloc(sizeof(struct key_user), GFP_KERNEL);
81 if (unlikely(!candidate))
82 goto out;
83
84 /* the allocation may have scheduled, so we need to repeat the
85 * search lest someone else added the record whilst we were
86 * asleep */
87 goto try_again;
88 }
89
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);
95 candidate->uid = uid;
96 candidate->qnkeys = 0;
97 candidate->qnbytes = 0;
98 spin_lock_init(&candidate->lock);
99 mutex_init(&candidate->cons_lock);
100
101 rb_link_node(&candidate->node, parent, p);
102 rb_insert_color(&candidate->node, &key_user_tree);
103 spin_unlock(&key_user_lock);
104 user = candidate;
105 goto out;
106
107 /* okay - we found a user record for this UID */
108found:
109 refcount_inc(&user->usage);
110 spin_unlock(&key_user_lock);
111 kfree(candidate);
112out:
113 return user;
114}
115
116/*
117 * Dispose of a user structure
118 */
119void key_user_put(struct key_user *user)
120{
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);
124
125 kfree(user);
126 }
127}
128
129/*
130 * Allocate a serial number for a key. These are assigned randomly to avoid
131 * security issues through covert channel problems.
132 */
133static inline void key_alloc_serial(struct key *key)
134{
135 struct rb_node *parent, **p;
136 struct key *xkey;
137
138 /* propose a random serial number and look for a hole for it in the
139 * serial number tree */
140 do {
141 get_random_bytes(&key->serial, sizeof(key->serial));
142
143 key->serial >>= 1; /* negative numbers are not permitted */
144 } while (key->serial < 3);
145
146 spin_lock(&key_serial_lock);
147
148attempt_insertion:
149 parent = NULL;
150 p = &key_serial_tree.rb_node;
151
152 while (*p) {
153 parent = *p;
154 xkey = rb_entry(parent, struct key, serial_node);
155
156 if (key->serial < xkey->serial)
157 p = &(*p)->rb_left;
158 else if (key->serial > xkey->serial)
159 p = &(*p)->rb_right;
160 else
161 goto serial_exists;
162 }
163
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);
167
168 spin_unlock(&key_serial_lock);
169 return;
170
171 /* we found a key with the proposed serial number - walk the tree from
172 * that point looking for the next unused serial number */
173serial_exists:
174 for (;;) {
175 key->serial++;
176 if (key->serial < 3) {
177 key->serial = 3;
178 goto attempt_insertion;
179 }
180
181 parent = rb_next(parent);
182 if (!parent)
183 goto attempt_insertion;
184
185 xkey = rb_entry(parent, struct key, serial_node);
186 if (key->serial < xkey->serial)
187 goto attempt_insertion;
188 }
189}
190
191/**
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.
201 *
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.
205 *
206 * The restrict_link structure (if not NULL) will be freed when the
207 * keyring is destroyed, so it must be dynamically allocated.
208 *
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.
213 *
214 * The LSM security modules can prevent a key being created, in which case
215 * -EACCES will be returned.
216 *
217 * Returns a pointer to the new key if successful and an error code otherwise.
218 *
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.
223 */
224struct 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)
228{
229 struct key_user *user = NULL;
230 struct key *key;
231 size_t desclen, quotalen;
232 int ret;
233 unsigned long irqflags;
234
235 key = ERR_PTR(-EINVAL);
236 if (!desc || !*desc)
237 goto error;
238
239 if (type->vet_description) {
240 ret = type->vet_description(desc);
241 if (ret < 0) {
242 key = ERR_PTR(ret);
243 goto error;
244 }
245 }
246
247 desclen = strlen(desc);
248 quotalen = desclen + 1 + type->def_datalen;
249
250 /* get hold of the key tracking for this user */
251 user = key_user_lookup(uid);
252 if (!user)
253 goto no_memory_1;
254
255 /* check that the user's quota permits allocation of another key and
256 * its description */
257 if (!(flags & KEY_ALLOC_NOT_IN_QUOTA)) {
258 unsigned maxkeys = uid_eq(uid, GLOBAL_ROOT_UID) ?
259 key_quota_root_maxkeys : key_quota_maxkeys;
260 unsigned maxbytes = uid_eq(uid, GLOBAL_ROOT_UID) ?
261 key_quota_root_maxbytes : key_quota_maxbytes;
262
263 spin_lock_irqsave(&user->lock, irqflags);
264 if (!(flags & KEY_ALLOC_QUOTA_OVERRUN)) {
265 if (user->qnkeys + 1 > maxkeys ||
266 user->qnbytes + quotalen > maxbytes ||
267 user->qnbytes + quotalen < user->qnbytes)
268 goto no_quota;
269 }
270
271 user->qnkeys++;
272 user->qnbytes += quotalen;
273 spin_unlock_irqrestore(&user->lock, irqflags);
274 }
275
276 /* allocate and initialise the key and its description */
277 key = kmem_cache_zalloc(key_jar, GFP_KERNEL);
278 if (!key)
279 goto no_memory_2;
280
281 key->index_key.desc_len = desclen;
282 key->index_key.description = kmemdup(desc, desclen + 1, GFP_KERNEL);
283 if (!key->index_key.description)
284 goto no_memory_3;
285 key->index_key.type = type;
286 key_set_index_key(&key->index_key);
287
288 refcount_set(&key->usage, 1);
289 init_rwsem(&key->sem);
290 lockdep_set_class(&key->sem, &type->lock_class);
291 key->user = user;
292 key->quotalen = quotalen;
293 key->datalen = type->def_datalen;
294 key->uid = uid;
295 key->gid = gid;
296 key->perm = perm;
297 key->expiry = TIME64_MAX;
298 key->restrict_link = restrict_link;
299 key->last_used_at = ktime_get_real_seconds();
300
301 if (!(flags & KEY_ALLOC_NOT_IN_QUOTA))
302 key->flags |= 1 << KEY_FLAG_IN_QUOTA;
303 if (flags & KEY_ALLOC_BUILT_IN)
304 key->flags |= 1 << KEY_FLAG_BUILTIN;
305 if (flags & KEY_ALLOC_UID_KEYRING)
306 key->flags |= 1 << KEY_FLAG_UID_KEYRING;
307 if (flags & KEY_ALLOC_SET_KEEP)
308 key->flags |= 1 << KEY_FLAG_KEEP;
309
310#ifdef KEY_DEBUGGING
311 key->magic = KEY_DEBUG_MAGIC;
312#endif
313
314 /* let the security module know about the key */
315 ret = security_key_alloc(key, cred, flags);
316 if (ret < 0)
317 goto security_error;
318
319 /* publish the key by giving it a serial number */
320 refcount_inc(&key->domain_tag->usage);
321 atomic_inc(&user->nkeys);
322 key_alloc_serial(key);
323
324error:
325 return key;
326
327security_error:
328 kfree(key->description);
329 kmem_cache_free(key_jar, key);
330 if (!(flags & KEY_ALLOC_NOT_IN_QUOTA)) {
331 spin_lock_irqsave(&user->lock, irqflags);
332 user->qnkeys--;
333 user->qnbytes -= quotalen;
334 spin_unlock_irqrestore(&user->lock, irqflags);
335 }
336 key_user_put(user);
337 key = ERR_PTR(ret);
338 goto error;
339
340no_memory_3:
341 kmem_cache_free(key_jar, key);
342no_memory_2:
343 if (!(flags & KEY_ALLOC_NOT_IN_QUOTA)) {
344 spin_lock_irqsave(&user->lock, irqflags);
345 user->qnkeys--;
346 user->qnbytes -= quotalen;
347 spin_unlock_irqrestore(&user->lock, irqflags);
348 }
349 key_user_put(user);
350no_memory_1:
351 key = ERR_PTR(-ENOMEM);
352 goto error;
353
354no_quota:
355 spin_unlock_irqrestore(&user->lock, irqflags);
356 key_user_put(user);
357 key = ERR_PTR(-EDQUOT);
358 goto error;
359}
360EXPORT_SYMBOL(key_alloc);
361
362/**
363 * key_payload_reserve - Adjust data quota reservation for the key's payload
364 * @key: The key to make the reservation for.
365 * @datalen: The amount of data payload the caller now wants.
366 *
367 * Adjust the amount of the owning user's key data quota that a key reserves.
368 * If the amount is increased, then -EDQUOT may be returned if there isn't
369 * enough free quota available.
370 *
371 * If successful, 0 is returned.
372 */
373int key_payload_reserve(struct key *key, size_t datalen)
374{
375 int delta = (int)datalen - key->datalen;
376 int ret = 0;
377
378 key_check(key);
379
380 /* contemplate the quota adjustment */
381 if (delta != 0 && test_bit(KEY_FLAG_IN_QUOTA, &key->flags)) {
382 unsigned maxbytes = uid_eq(key->user->uid, GLOBAL_ROOT_UID) ?
383 key_quota_root_maxbytes : key_quota_maxbytes;
384 unsigned long flags;
385
386 spin_lock_irqsave(&key->user->lock, flags);
387
388 if (delta > 0 &&
389 (key->user->qnbytes + delta > maxbytes ||
390 key->user->qnbytes + delta < key->user->qnbytes)) {
391 ret = -EDQUOT;
392 }
393 else {
394 key->user->qnbytes += delta;
395 key->quotalen += delta;
396 }
397 spin_unlock_irqrestore(&key->user->lock, flags);
398 }
399
400 /* change the recorded data length if that didn't generate an error */
401 if (ret == 0)
402 key->datalen = datalen;
403
404 return ret;
405}
406EXPORT_SYMBOL(key_payload_reserve);
407
408/*
409 * Change the key state to being instantiated.
410 */
411static void mark_key_instantiated(struct key *key, int reject_error)
412{
413 /* Commit the payload before setting the state; barrier versus
414 * key_read_state().
415 */
416 smp_store_release(&key->state,
417 (reject_error < 0) ? reject_error : KEY_IS_POSITIVE);
418}
419
420/*
421 * Instantiate a key and link it into the target keyring atomically. Must be
422 * called with the target keyring's semaphore writelocked. The target key's
423 * semaphore need not be locked as instantiation is serialised by
424 * key_construction_mutex.
425 */
426static int __key_instantiate_and_link(struct key *key,
427 struct key_preparsed_payload *prep,
428 struct key *keyring,
429 struct key *authkey,
430 struct assoc_array_edit **_edit)
431{
432 int ret, awaken;
433
434 key_check(key);
435 key_check(keyring);
436
437 awaken = 0;
438 ret = -EBUSY;
439
440 mutex_lock(&key_construction_mutex);
441
442 /* can't instantiate twice */
443 if (key->state == KEY_IS_UNINSTANTIATED) {
444 /* instantiate the key */
445 ret = key->type->instantiate(key, prep);
446
447 if (ret == 0) {
448 /* mark the key as being instantiated */
449 atomic_inc(&key->user->nikeys);
450 mark_key_instantiated(key, 0);
451 notify_key(key, NOTIFY_KEY_INSTANTIATED, 0);
452
453 if (test_and_clear_bit(KEY_FLAG_USER_CONSTRUCT, &key->flags))
454 awaken = 1;
455
456 /* and link it into the destination keyring */
457 if (keyring) {
458 if (test_bit(KEY_FLAG_KEEP, &keyring->flags))
459 set_bit(KEY_FLAG_KEEP, &key->flags);
460
461 __key_link(keyring, key, _edit);
462 }
463
464 /* disable the authorisation key */
465 if (authkey)
466 key_invalidate(authkey);
467
468 if (prep->expiry != TIME64_MAX)
469 key_set_expiry(key, prep->expiry);
470 }
471 }
472
473 mutex_unlock(&key_construction_mutex);
474
475 /* wake up anyone waiting for a key to be constructed */
476 if (awaken)
477 wake_up_bit(&key->flags, KEY_FLAG_USER_CONSTRUCT);
478
479 return ret;
480}
481
482/**
483 * key_instantiate_and_link - Instantiate a key and link it into the keyring.
484 * @key: The key to instantiate.
485 * @data: The data to use to instantiate the keyring.
486 * @datalen: The length of @data.
487 * @keyring: Keyring to create a link in on success (or NULL).
488 * @authkey: The authorisation token permitting instantiation.
489 *
490 * Instantiate a key that's in the uninstantiated state using the provided data
491 * and, if successful, link it in to the destination keyring if one is
492 * supplied.
493 *
494 * If successful, 0 is returned, the authorisation token is revoked and anyone
495 * waiting for the key is woken up. If the key was already instantiated,
496 * -EBUSY will be returned.
497 */
498int key_instantiate_and_link(struct key *key,
499 const void *data,
500 size_t datalen,
501 struct key *keyring,
502 struct key *authkey)
503{
504 struct key_preparsed_payload prep;
505 struct assoc_array_edit *edit = NULL;
506 int ret;
507
508 memset(&prep, 0, sizeof(prep));
509 prep.orig_description = key->description;
510 prep.data = data;
511 prep.datalen = datalen;
512 prep.quotalen = key->type->def_datalen;
513 prep.expiry = TIME64_MAX;
514 if (key->type->preparse) {
515 ret = key->type->preparse(&prep);
516 if (ret < 0)
517 goto error;
518 }
519
520 if (keyring) {
521 ret = __key_link_lock(keyring, &key->index_key);
522 if (ret < 0)
523 goto error;
524
525 ret = __key_link_begin(keyring, &key->index_key, &edit);
526 if (ret < 0)
527 goto error_link_end;
528
529 if (keyring->restrict_link && keyring->restrict_link->check) {
530 struct key_restriction *keyres = keyring->restrict_link;
531
532 ret = keyres->check(keyring, key->type, &prep.payload,
533 keyres->key);
534 if (ret < 0)
535 goto error_link_end;
536 }
537 }
538
539 ret = __key_instantiate_and_link(key, &prep, keyring, authkey, &edit);
540
541error_link_end:
542 if (keyring)
543 __key_link_end(keyring, &key->index_key, edit);
544
545error:
546 if (key->type->preparse)
547 key->type->free_preparse(&prep);
548 return ret;
549}
550
551EXPORT_SYMBOL(key_instantiate_and_link);
552
553/**
554 * key_reject_and_link - Negatively instantiate a key and link it into the keyring.
555 * @key: The key to instantiate.
556 * @timeout: The timeout on the negative key.
557 * @error: The error to return when the key is hit.
558 * @keyring: Keyring to create a link in on success (or NULL).
559 * @authkey: The authorisation token permitting instantiation.
560 *
561 * Negatively instantiate a key that's in the uninstantiated state and, if
562 * successful, set its timeout and stored error and link it in to the
563 * destination keyring if one is supplied. The key and any links to the key
564 * will be automatically garbage collected after the timeout expires.
565 *
566 * Negative keys are used to rate limit repeated request_key() calls by causing
567 * them to return the stored error code (typically ENOKEY) until the negative
568 * key expires.
569 *
570 * If successful, 0 is returned, the authorisation token is revoked and anyone
571 * waiting for the key is woken up. If the key was already instantiated,
572 * -EBUSY will be returned.
573 */
574int key_reject_and_link(struct key *key,
575 unsigned timeout,
576 unsigned error,
577 struct key *keyring,
578 struct key *authkey)
579{
580 struct assoc_array_edit *edit = NULL;
581 int ret, awaken, link_ret = 0;
582
583 key_check(key);
584 key_check(keyring);
585
586 awaken = 0;
587 ret = -EBUSY;
588
589 if (keyring) {
590 if (keyring->restrict_link)
591 return -EPERM;
592
593 link_ret = __key_link_lock(keyring, &key->index_key);
594 if (link_ret == 0) {
595 link_ret = __key_link_begin(keyring, &key->index_key, &edit);
596 if (link_ret < 0)
597 __key_link_end(keyring, &key->index_key, edit);
598 }
599 }
600
601 mutex_lock(&key_construction_mutex);
602
603 /* can't instantiate twice */
604 if (key->state == KEY_IS_UNINSTANTIATED) {
605 /* mark the key as being negatively instantiated */
606 atomic_inc(&key->user->nikeys);
607 mark_key_instantiated(key, -error);
608 notify_key(key, NOTIFY_KEY_INSTANTIATED, -error);
609 key_set_expiry(key, ktime_get_real_seconds() + timeout);
610
611 if (test_and_clear_bit(KEY_FLAG_USER_CONSTRUCT, &key->flags))
612 awaken = 1;
613
614 ret = 0;
615
616 /* and link it into the destination keyring */
617 if (keyring && link_ret == 0)
618 __key_link(keyring, key, &edit);
619
620 /* disable the authorisation key */
621 if (authkey)
622 key_invalidate(authkey);
623 }
624
625 mutex_unlock(&key_construction_mutex);
626
627 if (keyring && link_ret == 0)
628 __key_link_end(keyring, &key->index_key, edit);
629
630 /* wake up anyone waiting for a key to be constructed */
631 if (awaken)
632 wake_up_bit(&key->flags, KEY_FLAG_USER_CONSTRUCT);
633
634 return ret == 0 ? link_ret : ret;
635}
636EXPORT_SYMBOL(key_reject_and_link);
637
638/**
639 * key_put - Discard a reference to a key.
640 * @key: The key to discard a reference from.
641 *
642 * Discard a reference to a key, and when all the references are gone, we
643 * schedule the cleanup task to come and pull it out of the tree in process
644 * context at some later time.
645 */
646void key_put(struct key *key)
647{
648 if (key) {
649 key_check(key);
650
651 if (refcount_dec_and_test(&key->usage)) {
652 unsigned long flags;
653
654 /* deal with the user's key tracking and quota */
655 if (test_bit(KEY_FLAG_IN_QUOTA, &key->flags)) {
656 spin_lock_irqsave(&key->user->lock, flags);
657 key->user->qnkeys--;
658 key->user->qnbytes -= key->quotalen;
659 spin_unlock_irqrestore(&key->user->lock, flags);
660 }
661 schedule_work(&key_gc_work);
662 }
663 }
664}
665EXPORT_SYMBOL(key_put);
666
667/*
668 * Find a key by its serial number.
669 */
670struct key *key_lookup(key_serial_t id)
671{
672 struct rb_node *n;
673 struct key *key;
674
675 spin_lock(&key_serial_lock);
676
677 /* search the tree for the specified key */
678 n = key_serial_tree.rb_node;
679 while (n) {
680 key = rb_entry(n, struct key, serial_node);
681
682 if (id < key->serial)
683 n = n->rb_left;
684 else if (id > key->serial)
685 n = n->rb_right;
686 else
687 goto found;
688 }
689
690not_found:
691 key = ERR_PTR(-ENOKEY);
692 goto error;
693
694found:
695 /* A key is allowed to be looked up only if someone still owns a
696 * reference to it - otherwise it's awaiting the gc.
697 */
698 if (!refcount_inc_not_zero(&key->usage))
699 goto not_found;
700
701error:
702 spin_unlock(&key_serial_lock);
703 return key;
704}
705EXPORT_SYMBOL(key_lookup);
706
707/*
708 * Find and lock the specified key type against removal.
709 *
710 * We return with the sem read-locked if successful. If the type wasn't
711 * available -ENOKEY is returned instead.
712 */
713struct key_type *key_type_lookup(const char *type)
714{
715 struct key_type *ktype;
716
717 down_read(&key_types_sem);
718
719 /* look up the key type to see if it's one of the registered kernel
720 * types */
721 list_for_each_entry(ktype, &key_types_list, link) {
722 if (strcmp(ktype->name, type) == 0)
723 goto found_kernel_type;
724 }
725
726 up_read(&key_types_sem);
727 ktype = ERR_PTR(-ENOKEY);
728
729found_kernel_type:
730 return ktype;
731}
732
733void key_set_timeout(struct key *key, unsigned timeout)
734{
735 time64_t expiry = TIME64_MAX;
736
737 /* make the changes with the locks held to prevent races */
738 down_write(&key->sem);
739
740 if (timeout > 0)
741 expiry = ktime_get_real_seconds() + timeout;
742 key_set_expiry(key, expiry);
743
744 up_write(&key->sem);
745}
746EXPORT_SYMBOL_GPL(key_set_timeout);
747
748/*
749 * Unlock a key type locked by key_type_lookup().
750 */
751void key_type_put(struct key_type *ktype)
752{
753 up_read(&key_types_sem);
754}
755
756/*
757 * Attempt to update an existing key.
758 *
759 * The key is given to us with an incremented refcount that we need to discard
760 * if we get an error.
761 */
762static inline key_ref_t __key_update(key_ref_t key_ref,
763 struct key_preparsed_payload *prep)
764{
765 struct key *key = key_ref_to_ptr(key_ref);
766 int ret;
767
768 /* need write permission on the key to update it */
769 ret = key_permission(key_ref, KEY_NEED_WRITE);
770 if (ret < 0)
771 goto error;
772
773 ret = -EEXIST;
774 if (!key->type->update)
775 goto error;
776
777 down_write(&key->sem);
778
779 ret = key->type->update(key, prep);
780 if (ret == 0) {
781 /* Updating a negative key positively instantiates it */
782 mark_key_instantiated(key, 0);
783 notify_key(key, NOTIFY_KEY_UPDATED, 0);
784 }
785
786 up_write(&key->sem);
787
788 if (ret < 0)
789 goto error;
790out:
791 return key_ref;
792
793error:
794 key_put(key);
795 key_ref = ERR_PTR(ret);
796 goto out;
797}
798
799/*
800 * Create or potentially update a key. The combined logic behind
801 * key_create_or_update() and key_create()
802 */
803static key_ref_t __key_create_or_update(key_ref_t keyring_ref,
804 const char *type,
805 const char *description,
806 const void *payload,
807 size_t plen,
808 key_perm_t perm,
809 unsigned long flags,
810 bool allow_update)
811{
812 struct keyring_index_key index_key = {
813 .description = description,
814 };
815 struct key_preparsed_payload prep;
816 struct assoc_array_edit *edit = NULL;
817 const struct cred *cred = current_cred();
818 struct key *keyring, *key = NULL;
819 key_ref_t key_ref;
820 int ret;
821 struct key_restriction *restrict_link = NULL;
822
823 /* look up the key type to see if it's one of the registered kernel
824 * types */
825 index_key.type = key_type_lookup(type);
826 if (IS_ERR(index_key.type)) {
827 key_ref = ERR_PTR(-ENODEV);
828 goto error;
829 }
830
831 key_ref = ERR_PTR(-EINVAL);
832 if (!index_key.type->instantiate ||
833 (!index_key.description && !index_key.type->preparse))
834 goto error_put_type;
835
836 keyring = key_ref_to_ptr(keyring_ref);
837
838 key_check(keyring);
839
840 if (!(flags & KEY_ALLOC_BYPASS_RESTRICTION))
841 restrict_link = keyring->restrict_link;
842
843 key_ref = ERR_PTR(-ENOTDIR);
844 if (keyring->type != &key_type_keyring)
845 goto error_put_type;
846
847 memset(&prep, 0, sizeof(prep));
848 prep.orig_description = description;
849 prep.data = payload;
850 prep.datalen = plen;
851 prep.quotalen = index_key.type->def_datalen;
852 prep.expiry = TIME64_MAX;
853 if (index_key.type->preparse) {
854 ret = index_key.type->preparse(&prep);
855 if (ret < 0) {
856 key_ref = ERR_PTR(ret);
857 goto error_free_prep;
858 }
859 if (!index_key.description)
860 index_key.description = prep.description;
861 key_ref = ERR_PTR(-EINVAL);
862 if (!index_key.description)
863 goto error_free_prep;
864 }
865 index_key.desc_len = strlen(index_key.description);
866 key_set_index_key(&index_key);
867
868 ret = __key_link_lock(keyring, &index_key);
869 if (ret < 0) {
870 key_ref = ERR_PTR(ret);
871 goto error_free_prep;
872 }
873
874 ret = __key_link_begin(keyring, &index_key, &edit);
875 if (ret < 0) {
876 key_ref = ERR_PTR(ret);
877 goto error_link_end;
878 }
879
880 if (restrict_link && restrict_link->check) {
881 ret = restrict_link->check(keyring, index_key.type,
882 &prep.payload, restrict_link->key);
883 if (ret < 0) {
884 key_ref = ERR_PTR(ret);
885 goto error_link_end;
886 }
887 }
888
889 /* if we're going to allocate a new key, we're going to have
890 * to modify the keyring */
891 ret = key_permission(keyring_ref, KEY_NEED_WRITE);
892 if (ret < 0) {
893 key_ref = ERR_PTR(ret);
894 goto error_link_end;
895 }
896
897 /* if it's requested and possible to update this type of key, search
898 * for an existing key of the same type and description in the
899 * destination keyring and update that instead if possible
900 */
901 if (allow_update) {
902 if (index_key.type->update) {
903 key_ref = find_key_to_update(keyring_ref, &index_key);
904 if (key_ref)
905 goto found_matching_key;
906 }
907 } else {
908 key_ref = find_key_to_update(keyring_ref, &index_key);
909 if (key_ref) {
910 key_ref_put(key_ref);
911 key_ref = ERR_PTR(-EEXIST);
912 goto error_link_end;
913 }
914 }
915
916 /* if the client doesn't provide, decide on the permissions we want */
917 if (perm == KEY_PERM_UNDEF) {
918 perm = KEY_POS_VIEW | KEY_POS_SEARCH | KEY_POS_LINK | KEY_POS_SETATTR;
919 perm |= KEY_USR_VIEW;
920
921 if (index_key.type->read)
922 perm |= KEY_POS_READ;
923
924 if (index_key.type == &key_type_keyring ||
925 index_key.type->update)
926 perm |= KEY_POS_WRITE;
927 }
928
929 /* allocate a new key */
930 key = key_alloc(index_key.type, index_key.description,
931 cred->fsuid, cred->fsgid, cred, perm, flags, NULL);
932 if (IS_ERR(key)) {
933 key_ref = ERR_CAST(key);
934 goto error_link_end;
935 }
936
937 /* instantiate it and link it into the target keyring */
938 ret = __key_instantiate_and_link(key, &prep, keyring, NULL, &edit);
939 if (ret < 0) {
940 key_put(key);
941 key_ref = ERR_PTR(ret);
942 goto error_link_end;
943 }
944
945 security_key_post_create_or_update(keyring, key, payload, plen, flags,
946 true);
947
948 key_ref = make_key_ref(key, is_key_possessed(keyring_ref));
949
950error_link_end:
951 __key_link_end(keyring, &index_key, edit);
952error_free_prep:
953 if (index_key.type->preparse)
954 index_key.type->free_preparse(&prep);
955error_put_type:
956 key_type_put(index_key.type);
957error:
958 return key_ref;
959
960 found_matching_key:
961 /* we found a matching key, so we're going to try to update it
962 * - we can drop the locks first as we have the key pinned
963 */
964 __key_link_end(keyring, &index_key, edit);
965
966 key = key_ref_to_ptr(key_ref);
967 if (test_bit(KEY_FLAG_USER_CONSTRUCT, &key->flags)) {
968 ret = wait_for_key_construction(key, true);
969 if (ret < 0) {
970 key_ref_put(key_ref);
971 key_ref = ERR_PTR(ret);
972 goto error_free_prep;
973 }
974 }
975
976 key_ref = __key_update(key_ref, &prep);
977
978 if (!IS_ERR(key_ref))
979 security_key_post_create_or_update(keyring, key, payload, plen,
980 flags, false);
981
982 goto error_free_prep;
983}
984
985/**
986 * key_create_or_update - Update or create and instantiate a key.
987 * @keyring_ref: A pointer to the destination keyring with possession flag.
988 * @type: The type of key.
989 * @description: The searchable description for the key.
990 * @payload: The data to use to instantiate or update the key.
991 * @plen: The length of @payload.
992 * @perm: The permissions mask for a new key.
993 * @flags: The quota flags for a new key.
994 *
995 * Search the destination keyring for a key of the same description and if one
996 * is found, update it, otherwise create and instantiate a new one and create a
997 * link to it from that keyring.
998 *
999 * If perm is KEY_PERM_UNDEF then an appropriate key permissions mask will be
1000 * concocted.
1001 *
1002 * Returns a pointer to the new key if successful, -ENODEV if the key type
1003 * wasn't available, -ENOTDIR if the keyring wasn't a keyring, -EACCES if the
1004 * caller isn't permitted to modify the keyring or the LSM did not permit
1005 * creation of the key.
1006 *
1007 * On success, the possession flag from the keyring ref will be tacked on to
1008 * the key ref before it is returned.
1009 */
1010key_ref_t key_create_or_update(key_ref_t keyring_ref,
1011 const char *type,
1012 const char *description,
1013 const void *payload,
1014 size_t plen,
1015 key_perm_t perm,
1016 unsigned long flags)
1017{
1018 return __key_create_or_update(keyring_ref, type, description, payload,
1019 plen, perm, flags, true);
1020}
1021EXPORT_SYMBOL(key_create_or_update);
1022
1023/**
1024 * key_create - Create and instantiate a key.
1025 * @keyring_ref: A pointer to the destination keyring with possession flag.
1026 * @type: The type of key.
1027 * @description: The searchable description for the key.
1028 * @payload: The data to use to instantiate or update the key.
1029 * @plen: The length of @payload.
1030 * @perm: The permissions mask for a new key.
1031 * @flags: The quota flags for a new key.
1032 *
1033 * Create and instantiate a new key and link to it from the destination keyring.
1034 *
1035 * If perm is KEY_PERM_UNDEF then an appropriate key permissions mask will be
1036 * concocted.
1037 *
1038 * Returns a pointer to the new key if successful, -EEXIST if a key with the
1039 * same description already exists, -ENODEV if the key type wasn't available,
1040 * -ENOTDIR if the keyring wasn't a keyring, -EACCES if the caller isn't
1041 * permitted to modify the keyring or the LSM did not permit creation of the
1042 * key.
1043 *
1044 * On success, the possession flag from the keyring ref will be tacked on to
1045 * the key ref before it is returned.
1046 */
1047key_ref_t key_create(key_ref_t keyring_ref,
1048 const char *type,
1049 const char *description,
1050 const void *payload,
1051 size_t plen,
1052 key_perm_t perm,
1053 unsigned long flags)
1054{
1055 return __key_create_or_update(keyring_ref, type, description, payload,
1056 plen, perm, flags, false);
1057}
1058EXPORT_SYMBOL(key_create);
1059
1060/**
1061 * key_update - Update a key's contents.
1062 * @key_ref: The pointer (plus possession flag) to the key.
1063 * @payload: The data to be used to update the key.
1064 * @plen: The length of @payload.
1065 *
1066 * Attempt to update the contents of a key with the given payload data. The
1067 * caller must be granted Write permission on the key. Negative keys can be
1068 * instantiated by this method.
1069 *
1070 * Returns 0 on success, -EACCES if not permitted and -EOPNOTSUPP if the key
1071 * type does not support updating. The key type may return other errors.
1072 */
1073int key_update(key_ref_t key_ref, const void *payload, size_t plen)
1074{
1075 struct key_preparsed_payload prep;
1076 struct key *key = key_ref_to_ptr(key_ref);
1077 int ret;
1078
1079 key_check(key);
1080
1081 /* the key must be writable */
1082 ret = key_permission(key_ref, KEY_NEED_WRITE);
1083 if (ret < 0)
1084 return ret;
1085
1086 /* attempt to update it if supported */
1087 if (!key->type->update)
1088 return -EOPNOTSUPP;
1089
1090 memset(&prep, 0, sizeof(prep));
1091 prep.data = payload;
1092 prep.datalen = plen;
1093 prep.quotalen = key->type->def_datalen;
1094 prep.expiry = TIME64_MAX;
1095 if (key->type->preparse) {
1096 ret = key->type->preparse(&prep);
1097 if (ret < 0)
1098 goto error;
1099 }
1100
1101 down_write(&key->sem);
1102
1103 ret = key->type->update(key, &prep);
1104 if (ret == 0) {
1105 /* Updating a negative key positively instantiates it */
1106 mark_key_instantiated(key, 0);
1107 notify_key(key, NOTIFY_KEY_UPDATED, 0);
1108 }
1109
1110 up_write(&key->sem);
1111
1112error:
1113 if (key->type->preparse)
1114 key->type->free_preparse(&prep);
1115 return ret;
1116}
1117EXPORT_SYMBOL(key_update);
1118
1119/**
1120 * key_revoke - Revoke a key.
1121 * @key: The key to be revoked.
1122 *
1123 * Mark a key as being revoked and ask the type to free up its resources. The
1124 * revocation timeout is set and the key and all its links will be
1125 * automatically garbage collected after key_gc_delay amount of time if they
1126 * are not manually dealt with first.
1127 */
1128void key_revoke(struct key *key)
1129{
1130 time64_t time;
1131
1132 key_check(key);
1133
1134 /* make sure no one's trying to change or use the key when we mark it
1135 * - we tell lockdep that we might nest because we might be revoking an
1136 * authorisation key whilst holding the sem on a key we've just
1137 * instantiated
1138 */
1139 down_write_nested(&key->sem, 1);
1140 if (!test_and_set_bit(KEY_FLAG_REVOKED, &key->flags)) {
1141 notify_key(key, NOTIFY_KEY_REVOKED, 0);
1142 if (key->type->revoke)
1143 key->type->revoke(key);
1144
1145 /* set the death time to no more than the expiry time */
1146 time = ktime_get_real_seconds();
1147 if (key->revoked_at == 0 || key->revoked_at > time) {
1148 key->revoked_at = time;
1149 key_schedule_gc(key->revoked_at + key_gc_delay);
1150 }
1151 }
1152
1153 up_write(&key->sem);
1154}
1155EXPORT_SYMBOL(key_revoke);
1156
1157/**
1158 * key_invalidate - Invalidate a key.
1159 * @key: The key to be invalidated.
1160 *
1161 * Mark a key as being invalidated and have it cleaned up immediately. The key
1162 * is ignored by all searches and other operations from this point.
1163 */
1164void key_invalidate(struct key *key)
1165{
1166 kenter("%d", key_serial(key));
1167
1168 key_check(key);
1169
1170 if (!test_bit(KEY_FLAG_INVALIDATED, &key->flags)) {
1171 down_write_nested(&key->sem, 1);
1172 if (!test_and_set_bit(KEY_FLAG_INVALIDATED, &key->flags)) {
1173 notify_key(key, NOTIFY_KEY_INVALIDATED, 0);
1174 key_schedule_gc_links();
1175 }
1176 up_write(&key->sem);
1177 }
1178}
1179EXPORT_SYMBOL(key_invalidate);
1180
1181/**
1182 * generic_key_instantiate - Simple instantiation of a key from preparsed data
1183 * @key: The key to be instantiated
1184 * @prep: The preparsed data to load.
1185 *
1186 * Instantiate a key from preparsed data. We assume we can just copy the data
1187 * in directly and clear the old pointers.
1188 *
1189 * This can be pointed to directly by the key type instantiate op pointer.
1190 */
1191int generic_key_instantiate(struct key *key, struct key_preparsed_payload *prep)
1192{
1193 int ret;
1194
1195 pr_devel("==>%s()\n", __func__);
1196
1197 ret = key_payload_reserve(key, prep->quotalen);
1198 if (ret == 0) {
1199 rcu_assign_keypointer(key, prep->payload.data[0]);
1200 key->payload.data[1] = prep->payload.data[1];
1201 key->payload.data[2] = prep->payload.data[2];
1202 key->payload.data[3] = prep->payload.data[3];
1203 prep->payload.data[0] = NULL;
1204 prep->payload.data[1] = NULL;
1205 prep->payload.data[2] = NULL;
1206 prep->payload.data[3] = NULL;
1207 }
1208 pr_devel("<==%s() = %d\n", __func__, ret);
1209 return ret;
1210}
1211EXPORT_SYMBOL(generic_key_instantiate);
1212
1213/**
1214 * register_key_type - Register a type of key.
1215 * @ktype: The new key type.
1216 *
1217 * Register a new key type.
1218 *
1219 * Returns 0 on success or -EEXIST if a type of this name already exists.
1220 */
1221int register_key_type(struct key_type *ktype)
1222{
1223 struct key_type *p;
1224 int ret;
1225
1226 memset(&ktype->lock_class, 0, sizeof(ktype->lock_class));
1227
1228 ret = -EEXIST;
1229 down_write(&key_types_sem);
1230
1231 /* disallow key types with the same name */
1232 list_for_each_entry(p, &key_types_list, link) {
1233 if (strcmp(p->name, ktype->name) == 0)
1234 goto out;
1235 }
1236
1237 /* store the type */
1238 list_add(&ktype->link, &key_types_list);
1239
1240 pr_notice("Key type %s registered\n", ktype->name);
1241 ret = 0;
1242
1243out:
1244 up_write(&key_types_sem);
1245 return ret;
1246}
1247EXPORT_SYMBOL(register_key_type);
1248
1249/**
1250 * unregister_key_type - Unregister a type of key.
1251 * @ktype: The key type.
1252 *
1253 * Unregister a key type and mark all the extant keys of this type as dead.
1254 * Those keys of this type are then destroyed to get rid of their payloads and
1255 * they and their links will be garbage collected as soon as possible.
1256 */
1257void unregister_key_type(struct key_type *ktype)
1258{
1259 down_write(&key_types_sem);
1260 list_del_init(&ktype->link);
1261 downgrade_write(&key_types_sem);
1262 key_gc_keytype(ktype);
1263 pr_notice("Key type %s unregistered\n", ktype->name);
1264 up_read(&key_types_sem);
1265}
1266EXPORT_SYMBOL(unregister_key_type);
1267
1268/*
1269 * Initialise the key management state.
1270 */
1271void __init key_init(void)
1272{
1273 /* allocate a slab in which we can store keys */
1274 key_jar = kmem_cache_create("key_jar", sizeof(struct key),
1275 0, SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
1276
1277 /* add the special key types */
1278 list_add_tail(&key_type_keyring.link, &key_types_list);
1279 list_add_tail(&key_type_dead.link, &key_types_list);
1280 list_add_tail(&key_type_user.link, &key_types_list);
1281 list_add_tail(&key_type_logon.link, &key_types_list);
1282
1283 /* record the root user tracking */
1284 rb_link_node(&root_key_user.node,
1285 NULL,
1286 &key_user_tree.rb_node);
1287
1288 rb_insert_color(&root_key_user.node,
1289 &key_user_tree);
1290}