Loading...
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/ima.h>
17#include <linux/err.h>
18#include "internal.h"
19
20struct kmem_cache *key_jar;
21struct rb_root key_serial_tree; /* tree of keys indexed by serial */
22DEFINE_SPINLOCK(key_serial_lock);
23
24struct rb_root key_user_tree; /* tree of quota records indexed by UID */
25DEFINE_SPINLOCK(key_user_lock);
26
27unsigned int key_quota_root_maxkeys = 1000000; /* root's key count quota */
28unsigned int key_quota_root_maxbytes = 25000000; /* root's key space quota */
29unsigned int key_quota_maxkeys = 200; /* general key count quota */
30unsigned int key_quota_maxbytes = 20000; /* general key space quota */
31
32static LIST_HEAD(key_types_list);
33static DECLARE_RWSEM(key_types_sem);
34
35/* We serialise key instantiation and link */
36DEFINE_MUTEX(key_construction_mutex);
37
38#ifdef KEY_DEBUGGING
39void __key_check(const struct key *key)
40{
41 printk("__key_check: key %p {%08x} should be {%08x}\n",
42 key, key->magic, KEY_DEBUG_MAGIC);
43 BUG();
44}
45#endif
46
47/*
48 * Get the key quota record for a user, allocating a new record if one doesn't
49 * already exist.
50 */
51struct key_user *key_user_lookup(kuid_t uid)
52{
53 struct key_user *candidate = NULL, *user;
54 struct rb_node *parent, **p;
55
56try_again:
57 parent = NULL;
58 p = &key_user_tree.rb_node;
59 spin_lock(&key_user_lock);
60
61 /* search the tree for a user record with a matching UID */
62 while (*p) {
63 parent = *p;
64 user = rb_entry(parent, struct key_user, node);
65
66 if (uid_lt(uid, user->uid))
67 p = &(*p)->rb_left;
68 else if (uid_gt(uid, user->uid))
69 p = &(*p)->rb_right;
70 else
71 goto found;
72 }
73
74 /* if we get here, we failed to find a match in the tree */
75 if (!candidate) {
76 /* allocate a candidate user record if we don't already have
77 * one */
78 spin_unlock(&key_user_lock);
79
80 user = NULL;
81 candidate = kmalloc(sizeof(struct key_user), GFP_KERNEL);
82 if (unlikely(!candidate))
83 goto out;
84
85 /* the allocation may have scheduled, so we need to repeat the
86 * search lest someone else added the record whilst we were
87 * asleep */
88 goto try_again;
89 }
90
91 /* if we get here, then the user record still hadn't appeared on the
92 * second pass - so we use the candidate record */
93 refcount_set(&candidate->usage, 1);
94 atomic_set(&candidate->nkeys, 0);
95 atomic_set(&candidate->nikeys, 0);
96 candidate->uid = uid;
97 candidate->qnkeys = 0;
98 candidate->qnbytes = 0;
99 spin_lock_init(&candidate->lock);
100 mutex_init(&candidate->cons_lock);
101
102 rb_link_node(&candidate->node, parent, p);
103 rb_insert_color(&candidate->node, &key_user_tree);
104 spin_unlock(&key_user_lock);
105 user = candidate;
106 goto out;
107
108 /* okay - we found a user record for this UID */
109found:
110 refcount_inc(&user->usage);
111 spin_unlock(&key_user_lock);
112 kfree(candidate);
113out:
114 return user;
115}
116
117/*
118 * Dispose of a user structure
119 */
120void key_user_put(struct key_user *user)
121{
122 if (refcount_dec_and_lock(&user->usage, &key_user_lock)) {
123 rb_erase(&user->node, &key_user_tree);
124 spin_unlock(&key_user_lock);
125
126 kfree(user);
127 }
128}
129
130/*
131 * Allocate a serial number for a key. These are assigned randomly to avoid
132 * security issues through covert channel problems.
133 */
134static inline void key_alloc_serial(struct key *key)
135{
136 struct rb_node *parent, **p;
137 struct key *xkey;
138
139 /* propose a random serial number and look for a hole for it in the
140 * serial number tree */
141 do {
142 get_random_bytes(&key->serial, sizeof(key->serial));
143
144 key->serial >>= 1; /* negative numbers are not permitted */
145 } while (key->serial < 3);
146
147 spin_lock(&key_serial_lock);
148
149attempt_insertion:
150 parent = NULL;
151 p = &key_serial_tree.rb_node;
152
153 while (*p) {
154 parent = *p;
155 xkey = rb_entry(parent, struct key, serial_node);
156
157 if (key->serial < xkey->serial)
158 p = &(*p)->rb_left;
159 else if (key->serial > xkey->serial)
160 p = &(*p)->rb_right;
161 else
162 goto serial_exists;
163 }
164
165 /* we've found a suitable hole - arrange for this key to occupy it */
166 rb_link_node(&key->serial_node, parent, p);
167 rb_insert_color(&key->serial_node, &key_serial_tree);
168
169 spin_unlock(&key_serial_lock);
170 return;
171
172 /* we found a key with the proposed serial number - walk the tree from
173 * that point looking for the next unused serial number */
174serial_exists:
175 for (;;) {
176 key->serial++;
177 if (key->serial < 3) {
178 key->serial = 3;
179 goto attempt_insertion;
180 }
181
182 parent = rb_next(parent);
183 if (!parent)
184 goto attempt_insertion;
185
186 xkey = rb_entry(parent, struct key, serial_node);
187 if (key->serial < xkey->serial)
188 goto attempt_insertion;
189 }
190}
191
192/**
193 * key_alloc - Allocate a key of the specified type.
194 * @type: The type of key to allocate.
195 * @desc: The key description to allow the key to be searched out.
196 * @uid: The owner of the new key.
197 * @gid: The group ID for the new key's group permissions.
198 * @cred: The credentials specifying UID namespace.
199 * @perm: The permissions mask of the new key.
200 * @flags: Flags specifying quota properties.
201 * @restrict_link: Optional link restriction for new keyrings.
202 *
203 * Allocate a key of the specified type with the attributes given. The key is
204 * returned in an uninstantiated state and the caller needs to instantiate the
205 * key before returning.
206 *
207 * The restrict_link structure (if not NULL) will be freed when the
208 * keyring is destroyed, so it must be dynamically allocated.
209 *
210 * The user's key count quota is updated to reflect the creation of the key and
211 * the user's key data quota has the default for the key type reserved. The
212 * instantiation function should amend this as necessary. If insufficient
213 * quota is available, -EDQUOT will be returned.
214 *
215 * The LSM security modules can prevent a key being created, in which case
216 * -EACCES will be returned.
217 *
218 * Returns a pointer to the new key if successful and an error code otherwise.
219 *
220 * Note that the caller needs to ensure the key type isn't uninstantiated.
221 * Internally this can be done by locking key_types_sem. Externally, this can
222 * be done by either never unregistering the key type, or making sure
223 * key_alloc() calls don't race with module unloading.
224 */
225struct key *key_alloc(struct key_type *type, const char *desc,
226 kuid_t uid, kgid_t gid, const struct cred *cred,
227 key_perm_t perm, unsigned long flags,
228 struct key_restriction *restrict_link)
229{
230 struct key_user *user = NULL;
231 struct key *key;
232 size_t desclen, quotalen;
233 int ret;
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(&user->lock);
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(&user->lock);
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->restrict_link = restrict_link;
298 key->last_used_at = ktime_get_real_seconds();
299
300 if (!(flags & KEY_ALLOC_NOT_IN_QUOTA))
301 key->flags |= 1 << KEY_FLAG_IN_QUOTA;
302 if (flags & KEY_ALLOC_BUILT_IN)
303 key->flags |= 1 << KEY_FLAG_BUILTIN;
304 if (flags & KEY_ALLOC_UID_KEYRING)
305 key->flags |= 1 << KEY_FLAG_UID_KEYRING;
306
307#ifdef KEY_DEBUGGING
308 key->magic = KEY_DEBUG_MAGIC;
309#endif
310
311 /* let the security module know about the key */
312 ret = security_key_alloc(key, cred, flags);
313 if (ret < 0)
314 goto security_error;
315
316 /* publish the key by giving it a serial number */
317 refcount_inc(&key->domain_tag->usage);
318 atomic_inc(&user->nkeys);
319 key_alloc_serial(key);
320
321error:
322 return key;
323
324security_error:
325 kfree(key->description);
326 kmem_cache_free(key_jar, key);
327 if (!(flags & KEY_ALLOC_NOT_IN_QUOTA)) {
328 spin_lock(&user->lock);
329 user->qnkeys--;
330 user->qnbytes -= quotalen;
331 spin_unlock(&user->lock);
332 }
333 key_user_put(user);
334 key = ERR_PTR(ret);
335 goto error;
336
337no_memory_3:
338 kmem_cache_free(key_jar, key);
339no_memory_2:
340 if (!(flags & KEY_ALLOC_NOT_IN_QUOTA)) {
341 spin_lock(&user->lock);
342 user->qnkeys--;
343 user->qnbytes -= quotalen;
344 spin_unlock(&user->lock);
345 }
346 key_user_put(user);
347no_memory_1:
348 key = ERR_PTR(-ENOMEM);
349 goto error;
350
351no_quota:
352 spin_unlock(&user->lock);
353 key_user_put(user);
354 key = ERR_PTR(-EDQUOT);
355 goto error;
356}
357EXPORT_SYMBOL(key_alloc);
358
359/**
360 * key_payload_reserve - Adjust data quota reservation for the key's payload
361 * @key: The key to make the reservation for.
362 * @datalen: The amount of data payload the caller now wants.
363 *
364 * Adjust the amount of the owning user's key data quota that a key reserves.
365 * If the amount is increased, then -EDQUOT may be returned if there isn't
366 * enough free quota available.
367 *
368 * If successful, 0 is returned.
369 */
370int key_payload_reserve(struct key *key, size_t datalen)
371{
372 int delta = (int)datalen - key->datalen;
373 int ret = 0;
374
375 key_check(key);
376
377 /* contemplate the quota adjustment */
378 if (delta != 0 && test_bit(KEY_FLAG_IN_QUOTA, &key->flags)) {
379 unsigned maxbytes = uid_eq(key->user->uid, GLOBAL_ROOT_UID) ?
380 key_quota_root_maxbytes : key_quota_maxbytes;
381
382 spin_lock(&key->user->lock);
383
384 if (delta > 0 &&
385 (key->user->qnbytes + delta > maxbytes ||
386 key->user->qnbytes + delta < key->user->qnbytes)) {
387 ret = -EDQUOT;
388 }
389 else {
390 key->user->qnbytes += delta;
391 key->quotalen += delta;
392 }
393 spin_unlock(&key->user->lock);
394 }
395
396 /* change the recorded data length if that didn't generate an error */
397 if (ret == 0)
398 key->datalen = datalen;
399
400 return ret;
401}
402EXPORT_SYMBOL(key_payload_reserve);
403
404/*
405 * Change the key state to being instantiated.
406 */
407static void mark_key_instantiated(struct key *key, int reject_error)
408{
409 /* Commit the payload before setting the state; barrier versus
410 * key_read_state().
411 */
412 smp_store_release(&key->state,
413 (reject_error < 0) ? reject_error : KEY_IS_POSITIVE);
414}
415
416/*
417 * Instantiate a key and link it into the target keyring atomically. Must be
418 * called with the target keyring's semaphore writelocked. The target key's
419 * semaphore need not be locked as instantiation is serialised by
420 * key_construction_mutex.
421 */
422static int __key_instantiate_and_link(struct key *key,
423 struct key_preparsed_payload *prep,
424 struct key *keyring,
425 struct key *authkey,
426 struct assoc_array_edit **_edit)
427{
428 int ret, awaken;
429
430 key_check(key);
431 key_check(keyring);
432
433 awaken = 0;
434 ret = -EBUSY;
435
436 mutex_lock(&key_construction_mutex);
437
438 /* can't instantiate twice */
439 if (key->state == KEY_IS_UNINSTANTIATED) {
440 /* instantiate the key */
441 ret = key->type->instantiate(key, prep);
442
443 if (ret == 0) {
444 /* mark the key as being instantiated */
445 atomic_inc(&key->user->nikeys);
446 mark_key_instantiated(key, 0);
447 notify_key(key, NOTIFY_KEY_INSTANTIATED, 0);
448
449 if (test_and_clear_bit(KEY_FLAG_USER_CONSTRUCT, &key->flags))
450 awaken = 1;
451
452 /* and link it into the destination keyring */
453 if (keyring) {
454 if (test_bit(KEY_FLAG_KEEP, &keyring->flags))
455 set_bit(KEY_FLAG_KEEP, &key->flags);
456
457 __key_link(keyring, key, _edit);
458 }
459
460 /* disable the authorisation key */
461 if (authkey)
462 key_invalidate(authkey);
463
464 if (prep->expiry != TIME64_MAX) {
465 key->expiry = prep->expiry;
466 key_schedule_gc(prep->expiry + key_gc_delay);
467 }
468 }
469 }
470
471 mutex_unlock(&key_construction_mutex);
472
473 /* wake up anyone waiting for a key to be constructed */
474 if (awaken)
475 wake_up_bit(&key->flags, KEY_FLAG_USER_CONSTRUCT);
476
477 return ret;
478}
479
480/**
481 * key_instantiate_and_link - Instantiate a key and link it into the keyring.
482 * @key: The key to instantiate.
483 * @data: The data to use to instantiate the keyring.
484 * @datalen: The length of @data.
485 * @keyring: Keyring to create a link in on success (or NULL).
486 * @authkey: The authorisation token permitting instantiation.
487 *
488 * Instantiate a key that's in the uninstantiated state using the provided data
489 * and, if successful, link it in to the destination keyring if one is
490 * supplied.
491 *
492 * If successful, 0 is returned, the authorisation token is revoked and anyone
493 * waiting for the key is woken up. If the key was already instantiated,
494 * -EBUSY will be returned.
495 */
496int key_instantiate_and_link(struct key *key,
497 const void *data,
498 size_t datalen,
499 struct key *keyring,
500 struct key *authkey)
501{
502 struct key_preparsed_payload prep;
503 struct assoc_array_edit *edit = NULL;
504 int ret;
505
506 memset(&prep, 0, sizeof(prep));
507 prep.data = data;
508 prep.datalen = datalen;
509 prep.quotalen = key->type->def_datalen;
510 prep.expiry = TIME64_MAX;
511 if (key->type->preparse) {
512 ret = key->type->preparse(&prep);
513 if (ret < 0)
514 goto error;
515 }
516
517 if (keyring) {
518 ret = __key_link_lock(keyring, &key->index_key);
519 if (ret < 0)
520 goto error;
521
522 ret = __key_link_begin(keyring, &key->index_key, &edit);
523 if (ret < 0)
524 goto error_link_end;
525
526 if (keyring->restrict_link && keyring->restrict_link->check) {
527 struct key_restriction *keyres = keyring->restrict_link;
528
529 ret = keyres->check(keyring, key->type, &prep.payload,
530 keyres->key);
531 if (ret < 0)
532 goto error_link_end;
533 }
534 }
535
536 ret = __key_instantiate_and_link(key, &prep, keyring, authkey, &edit);
537
538error_link_end:
539 if (keyring)
540 __key_link_end(keyring, &key->index_key, edit);
541
542error:
543 if (key->type->preparse)
544 key->type->free_preparse(&prep);
545 return ret;
546}
547
548EXPORT_SYMBOL(key_instantiate_and_link);
549
550/**
551 * key_reject_and_link - Negatively instantiate a key and link it into the keyring.
552 * @key: The key to instantiate.
553 * @timeout: The timeout on the negative key.
554 * @error: The error to return when the key is hit.
555 * @keyring: Keyring to create a link in on success (or NULL).
556 * @authkey: The authorisation token permitting instantiation.
557 *
558 * Negatively instantiate a key that's in the uninstantiated state and, if
559 * successful, set its timeout and stored error and link it in to the
560 * destination keyring if one is supplied. The key and any links to the key
561 * will be automatically garbage collected after the timeout expires.
562 *
563 * Negative keys are used to rate limit repeated request_key() calls by causing
564 * them to return the stored error code (typically ENOKEY) until the negative
565 * key expires.
566 *
567 * If successful, 0 is returned, the authorisation token is revoked and anyone
568 * waiting for the key is woken up. If the key was already instantiated,
569 * -EBUSY will be returned.
570 */
571int key_reject_and_link(struct key *key,
572 unsigned timeout,
573 unsigned error,
574 struct key *keyring,
575 struct key *authkey)
576{
577 struct assoc_array_edit *edit = NULL;
578 int ret, awaken, link_ret = 0;
579
580 key_check(key);
581 key_check(keyring);
582
583 awaken = 0;
584 ret = -EBUSY;
585
586 if (keyring) {
587 if (keyring->restrict_link)
588 return -EPERM;
589
590 link_ret = __key_link_lock(keyring, &key->index_key);
591 if (link_ret == 0) {
592 link_ret = __key_link_begin(keyring, &key->index_key, &edit);
593 if (link_ret < 0)
594 __key_link_end(keyring, &key->index_key, edit);
595 }
596 }
597
598 mutex_lock(&key_construction_mutex);
599
600 /* can't instantiate twice */
601 if (key->state == KEY_IS_UNINSTANTIATED) {
602 /* mark the key as being negatively instantiated */
603 atomic_inc(&key->user->nikeys);
604 mark_key_instantiated(key, -error);
605 notify_key(key, NOTIFY_KEY_INSTANTIATED, -error);
606 key->expiry = ktime_get_real_seconds() + timeout;
607 key_schedule_gc(key->expiry + key_gc_delay);
608
609 if (test_and_clear_bit(KEY_FLAG_USER_CONSTRUCT, &key->flags))
610 awaken = 1;
611
612 ret = 0;
613
614 /* and link it into the destination keyring */
615 if (keyring && link_ret == 0)
616 __key_link(keyring, key, &edit);
617
618 /* disable the authorisation key */
619 if (authkey)
620 key_invalidate(authkey);
621 }
622
623 mutex_unlock(&key_construction_mutex);
624
625 if (keyring && link_ret == 0)
626 __key_link_end(keyring, &key->index_key, edit);
627
628 /* wake up anyone waiting for a key to be constructed */
629 if (awaken)
630 wake_up_bit(&key->flags, KEY_FLAG_USER_CONSTRUCT);
631
632 return ret == 0 ? link_ret : ret;
633}
634EXPORT_SYMBOL(key_reject_and_link);
635
636/**
637 * key_put - Discard a reference to a key.
638 * @key: The key to discard a reference from.
639 *
640 * Discard a reference to a key, and when all the references are gone, we
641 * schedule the cleanup task to come and pull it out of the tree in process
642 * context at some later time.
643 */
644void key_put(struct key *key)
645{
646 if (key) {
647 key_check(key);
648
649 if (refcount_dec_and_test(&key->usage))
650 schedule_work(&key_gc_work);
651 }
652}
653EXPORT_SYMBOL(key_put);
654
655/*
656 * Find a key by its serial number.
657 */
658struct key *key_lookup(key_serial_t id)
659{
660 struct rb_node *n;
661 struct key *key;
662
663 spin_lock(&key_serial_lock);
664
665 /* search the tree for the specified key */
666 n = key_serial_tree.rb_node;
667 while (n) {
668 key = rb_entry(n, struct key, serial_node);
669
670 if (id < key->serial)
671 n = n->rb_left;
672 else if (id > key->serial)
673 n = n->rb_right;
674 else
675 goto found;
676 }
677
678not_found:
679 key = ERR_PTR(-ENOKEY);
680 goto error;
681
682found:
683 /* A key is allowed to be looked up only if someone still owns a
684 * reference to it - otherwise it's awaiting the gc.
685 */
686 if (!refcount_inc_not_zero(&key->usage))
687 goto not_found;
688
689error:
690 spin_unlock(&key_serial_lock);
691 return key;
692}
693
694/*
695 * Find and lock the specified key type against removal.
696 *
697 * We return with the sem read-locked if successful. If the type wasn't
698 * available -ENOKEY is returned instead.
699 */
700struct key_type *key_type_lookup(const char *type)
701{
702 struct key_type *ktype;
703
704 down_read(&key_types_sem);
705
706 /* look up the key type to see if it's one of the registered kernel
707 * types */
708 list_for_each_entry(ktype, &key_types_list, link) {
709 if (strcmp(ktype->name, type) == 0)
710 goto found_kernel_type;
711 }
712
713 up_read(&key_types_sem);
714 ktype = ERR_PTR(-ENOKEY);
715
716found_kernel_type:
717 return ktype;
718}
719
720void key_set_timeout(struct key *key, unsigned timeout)
721{
722 time64_t expiry = 0;
723
724 /* make the changes with the locks held to prevent races */
725 down_write(&key->sem);
726
727 if (timeout > 0)
728 expiry = ktime_get_real_seconds() + timeout;
729
730 key->expiry = expiry;
731 key_schedule_gc(key->expiry + key_gc_delay);
732
733 up_write(&key->sem);
734}
735EXPORT_SYMBOL_GPL(key_set_timeout);
736
737/*
738 * Unlock a key type locked by key_type_lookup().
739 */
740void key_type_put(struct key_type *ktype)
741{
742 up_read(&key_types_sem);
743}
744
745/*
746 * Attempt to update an existing key.
747 *
748 * The key is given to us with an incremented refcount that we need to discard
749 * if we get an error.
750 */
751static inline key_ref_t __key_update(key_ref_t key_ref,
752 struct key_preparsed_payload *prep)
753{
754 struct key *key = key_ref_to_ptr(key_ref);
755 int ret;
756
757 /* need write permission on the key to update it */
758 ret = key_permission(key_ref, KEY_NEED_WRITE);
759 if (ret < 0)
760 goto error;
761
762 ret = -EEXIST;
763 if (!key->type->update)
764 goto error;
765
766 down_write(&key->sem);
767
768 ret = key->type->update(key, prep);
769 if (ret == 0) {
770 /* Updating a negative key positively instantiates it */
771 mark_key_instantiated(key, 0);
772 notify_key(key, NOTIFY_KEY_UPDATED, 0);
773 }
774
775 up_write(&key->sem);
776
777 if (ret < 0)
778 goto error;
779out:
780 return key_ref;
781
782error:
783 key_put(key);
784 key_ref = ERR_PTR(ret);
785 goto out;
786}
787
788/**
789 * key_create_or_update - Update or create and instantiate a key.
790 * @keyring_ref: A pointer to the destination keyring with possession flag.
791 * @type: The type of key.
792 * @description: The searchable description for the key.
793 * @payload: The data to use to instantiate or update the key.
794 * @plen: The length of @payload.
795 * @perm: The permissions mask for a new key.
796 * @flags: The quota flags for a new key.
797 *
798 * Search the destination keyring for a key of the same description and if one
799 * is found, update it, otherwise create and instantiate a new one and create a
800 * link to it from that keyring.
801 *
802 * If perm is KEY_PERM_UNDEF then an appropriate key permissions mask will be
803 * concocted.
804 *
805 * Returns a pointer to the new key if successful, -ENODEV if the key type
806 * wasn't available, -ENOTDIR if the keyring wasn't a keyring, -EACCES if the
807 * caller isn't permitted to modify the keyring or the LSM did not permit
808 * creation of the key.
809 *
810 * On success, the possession flag from the keyring ref will be tacked on to
811 * the key ref before it is returned.
812 */
813key_ref_t key_create_or_update(key_ref_t keyring_ref,
814 const char *type,
815 const char *description,
816 const void *payload,
817 size_t plen,
818 key_perm_t perm,
819 unsigned long flags)
820{
821 struct keyring_index_key index_key = {
822 .description = description,
823 };
824 struct key_preparsed_payload prep;
825 struct assoc_array_edit *edit = NULL;
826 const struct cred *cred = current_cred();
827 struct key *keyring, *key = NULL;
828 key_ref_t key_ref;
829 int ret;
830 struct key_restriction *restrict_link = NULL;
831
832 /* look up the key type to see if it's one of the registered kernel
833 * types */
834 index_key.type = key_type_lookup(type);
835 if (IS_ERR(index_key.type)) {
836 key_ref = ERR_PTR(-ENODEV);
837 goto error;
838 }
839
840 key_ref = ERR_PTR(-EINVAL);
841 if (!index_key.type->instantiate ||
842 (!index_key.description && !index_key.type->preparse))
843 goto error_put_type;
844
845 keyring = key_ref_to_ptr(keyring_ref);
846
847 key_check(keyring);
848
849 if (!(flags & KEY_ALLOC_BYPASS_RESTRICTION))
850 restrict_link = keyring->restrict_link;
851
852 key_ref = ERR_PTR(-ENOTDIR);
853 if (keyring->type != &key_type_keyring)
854 goto error_put_type;
855
856 memset(&prep, 0, sizeof(prep));
857 prep.data = payload;
858 prep.datalen = plen;
859 prep.quotalen = index_key.type->def_datalen;
860 prep.expiry = TIME64_MAX;
861 if (index_key.type->preparse) {
862 ret = index_key.type->preparse(&prep);
863 if (ret < 0) {
864 key_ref = ERR_PTR(ret);
865 goto error_free_prep;
866 }
867 if (!index_key.description)
868 index_key.description = prep.description;
869 key_ref = ERR_PTR(-EINVAL);
870 if (!index_key.description)
871 goto error_free_prep;
872 }
873 index_key.desc_len = strlen(index_key.description);
874 key_set_index_key(&index_key);
875
876 ret = __key_link_lock(keyring, &index_key);
877 if (ret < 0) {
878 key_ref = ERR_PTR(ret);
879 goto error_free_prep;
880 }
881
882 ret = __key_link_begin(keyring, &index_key, &edit);
883 if (ret < 0) {
884 key_ref = ERR_PTR(ret);
885 goto error_link_end;
886 }
887
888 if (restrict_link && restrict_link->check) {
889 ret = restrict_link->check(keyring, index_key.type,
890 &prep.payload, restrict_link->key);
891 if (ret < 0) {
892 key_ref = ERR_PTR(ret);
893 goto error_link_end;
894 }
895 }
896
897 /* if we're going to allocate a new key, we're going to have
898 * to modify the keyring */
899 ret = key_permission(keyring_ref, KEY_NEED_WRITE);
900 if (ret < 0) {
901 key_ref = ERR_PTR(ret);
902 goto error_link_end;
903 }
904
905 /* if it's possible to update this type of key, search for an existing
906 * key of the same type and description in the destination keyring and
907 * update that instead if possible
908 */
909 if (index_key.type->update) {
910 key_ref = find_key_to_update(keyring_ref, &index_key);
911 if (key_ref)
912 goto found_matching_key;
913 }
914
915 /* if the client doesn't provide, decide on the permissions we want */
916 if (perm == KEY_PERM_UNDEF) {
917 perm = KEY_POS_VIEW | KEY_POS_SEARCH | KEY_POS_LINK | KEY_POS_SETATTR;
918 perm |= KEY_USR_VIEW;
919
920 if (index_key.type->read)
921 perm |= KEY_POS_READ;
922
923 if (index_key.type == &key_type_keyring ||
924 index_key.type->update)
925 perm |= KEY_POS_WRITE;
926 }
927
928 /* allocate a new key */
929 key = key_alloc(index_key.type, index_key.description,
930 cred->fsuid, cred->fsgid, cred, perm, flags, NULL);
931 if (IS_ERR(key)) {
932 key_ref = ERR_CAST(key);
933 goto error_link_end;
934 }
935
936 /* instantiate it and link it into the target keyring */
937 ret = __key_instantiate_and_link(key, &prep, keyring, NULL, &edit);
938 if (ret < 0) {
939 key_put(key);
940 key_ref = ERR_PTR(ret);
941 goto error_link_end;
942 }
943
944 ima_post_key_create_or_update(keyring, key, payload, plen,
945 flags, true);
946
947 key_ref = make_key_ref(key, is_key_possessed(keyring_ref));
948
949error_link_end:
950 __key_link_end(keyring, &index_key, edit);
951error_free_prep:
952 if (index_key.type->preparse)
953 index_key.type->free_preparse(&prep);
954error_put_type:
955 key_type_put(index_key.type);
956error:
957 return key_ref;
958
959 found_matching_key:
960 /* we found a matching key, so we're going to try to update it
961 * - we can drop the locks first as we have the key pinned
962 */
963 __key_link_end(keyring, &index_key, edit);
964
965 key = key_ref_to_ptr(key_ref);
966 if (test_bit(KEY_FLAG_USER_CONSTRUCT, &key->flags)) {
967 ret = wait_for_key_construction(key, true);
968 if (ret < 0) {
969 key_ref_put(key_ref);
970 key_ref = ERR_PTR(ret);
971 goto error_free_prep;
972 }
973 }
974
975 key_ref = __key_update(key_ref, &prep);
976
977 if (!IS_ERR(key_ref))
978 ima_post_key_create_or_update(keyring, key,
979 payload, plen,
980 flags, false);
981
982 goto error_free_prep;
983}
984EXPORT_SYMBOL(key_create_or_update);
985
986/**
987 * key_update - Update a key's contents.
988 * @key_ref: The pointer (plus possession flag) to the key.
989 * @payload: The data to be used to update the key.
990 * @plen: The length of @payload.
991 *
992 * Attempt to update the contents of a key with the given payload data. The
993 * caller must be granted Write permission on the key. Negative keys can be
994 * instantiated by this method.
995 *
996 * Returns 0 on success, -EACCES if not permitted and -EOPNOTSUPP if the key
997 * type does not support updating. The key type may return other errors.
998 */
999int key_update(key_ref_t key_ref, const void *payload, size_t plen)
1000{
1001 struct key_preparsed_payload prep;
1002 struct key *key = key_ref_to_ptr(key_ref);
1003 int ret;
1004
1005 key_check(key);
1006
1007 /* the key must be writable */
1008 ret = key_permission(key_ref, KEY_NEED_WRITE);
1009 if (ret < 0)
1010 return ret;
1011
1012 /* attempt to update it if supported */
1013 if (!key->type->update)
1014 return -EOPNOTSUPP;
1015
1016 memset(&prep, 0, sizeof(prep));
1017 prep.data = payload;
1018 prep.datalen = plen;
1019 prep.quotalen = key->type->def_datalen;
1020 prep.expiry = TIME64_MAX;
1021 if (key->type->preparse) {
1022 ret = key->type->preparse(&prep);
1023 if (ret < 0)
1024 goto error;
1025 }
1026
1027 down_write(&key->sem);
1028
1029 ret = key->type->update(key, &prep);
1030 if (ret == 0) {
1031 /* Updating a negative key positively instantiates it */
1032 mark_key_instantiated(key, 0);
1033 notify_key(key, NOTIFY_KEY_UPDATED, 0);
1034 }
1035
1036 up_write(&key->sem);
1037
1038error:
1039 if (key->type->preparse)
1040 key->type->free_preparse(&prep);
1041 return ret;
1042}
1043EXPORT_SYMBOL(key_update);
1044
1045/**
1046 * key_revoke - Revoke a key.
1047 * @key: The key to be revoked.
1048 *
1049 * Mark a key as being revoked and ask the type to free up its resources. The
1050 * revocation timeout is set and the key and all its links will be
1051 * automatically garbage collected after key_gc_delay amount of time if they
1052 * are not manually dealt with first.
1053 */
1054void key_revoke(struct key *key)
1055{
1056 time64_t time;
1057
1058 key_check(key);
1059
1060 /* make sure no one's trying to change or use the key when we mark it
1061 * - we tell lockdep that we might nest because we might be revoking an
1062 * authorisation key whilst holding the sem on a key we've just
1063 * instantiated
1064 */
1065 down_write_nested(&key->sem, 1);
1066 if (!test_and_set_bit(KEY_FLAG_REVOKED, &key->flags)) {
1067 notify_key(key, NOTIFY_KEY_REVOKED, 0);
1068 if (key->type->revoke)
1069 key->type->revoke(key);
1070
1071 /* set the death time to no more than the expiry time */
1072 time = ktime_get_real_seconds();
1073 if (key->revoked_at == 0 || key->revoked_at > time) {
1074 key->revoked_at = time;
1075 key_schedule_gc(key->revoked_at + key_gc_delay);
1076 }
1077 }
1078
1079 up_write(&key->sem);
1080}
1081EXPORT_SYMBOL(key_revoke);
1082
1083/**
1084 * key_invalidate - Invalidate a key.
1085 * @key: The key to be invalidated.
1086 *
1087 * Mark a key as being invalidated and have it cleaned up immediately. The key
1088 * is ignored by all searches and other operations from this point.
1089 */
1090void key_invalidate(struct key *key)
1091{
1092 kenter("%d", key_serial(key));
1093
1094 key_check(key);
1095
1096 if (!test_bit(KEY_FLAG_INVALIDATED, &key->flags)) {
1097 down_write_nested(&key->sem, 1);
1098 if (!test_and_set_bit(KEY_FLAG_INVALIDATED, &key->flags)) {
1099 notify_key(key, NOTIFY_KEY_INVALIDATED, 0);
1100 key_schedule_gc_links();
1101 }
1102 up_write(&key->sem);
1103 }
1104}
1105EXPORT_SYMBOL(key_invalidate);
1106
1107/**
1108 * generic_key_instantiate - Simple instantiation of a key from preparsed data
1109 * @key: The key to be instantiated
1110 * @prep: The preparsed data to load.
1111 *
1112 * Instantiate a key from preparsed data. We assume we can just copy the data
1113 * in directly and clear the old pointers.
1114 *
1115 * This can be pointed to directly by the key type instantiate op pointer.
1116 */
1117int generic_key_instantiate(struct key *key, struct key_preparsed_payload *prep)
1118{
1119 int ret;
1120
1121 pr_devel("==>%s()\n", __func__);
1122
1123 ret = key_payload_reserve(key, prep->quotalen);
1124 if (ret == 0) {
1125 rcu_assign_keypointer(key, prep->payload.data[0]);
1126 key->payload.data[1] = prep->payload.data[1];
1127 key->payload.data[2] = prep->payload.data[2];
1128 key->payload.data[3] = prep->payload.data[3];
1129 prep->payload.data[0] = NULL;
1130 prep->payload.data[1] = NULL;
1131 prep->payload.data[2] = NULL;
1132 prep->payload.data[3] = NULL;
1133 }
1134 pr_devel("<==%s() = %d\n", __func__, ret);
1135 return ret;
1136}
1137EXPORT_SYMBOL(generic_key_instantiate);
1138
1139/**
1140 * register_key_type - Register a type of key.
1141 * @ktype: The new key type.
1142 *
1143 * Register a new key type.
1144 *
1145 * Returns 0 on success or -EEXIST if a type of this name already exists.
1146 */
1147int register_key_type(struct key_type *ktype)
1148{
1149 struct key_type *p;
1150 int ret;
1151
1152 memset(&ktype->lock_class, 0, sizeof(ktype->lock_class));
1153
1154 ret = -EEXIST;
1155 down_write(&key_types_sem);
1156
1157 /* disallow key types with the same name */
1158 list_for_each_entry(p, &key_types_list, link) {
1159 if (strcmp(p->name, ktype->name) == 0)
1160 goto out;
1161 }
1162
1163 /* store the type */
1164 list_add(&ktype->link, &key_types_list);
1165
1166 pr_notice("Key type %s registered\n", ktype->name);
1167 ret = 0;
1168
1169out:
1170 up_write(&key_types_sem);
1171 return ret;
1172}
1173EXPORT_SYMBOL(register_key_type);
1174
1175/**
1176 * unregister_key_type - Unregister a type of key.
1177 * @ktype: The key type.
1178 *
1179 * Unregister a key type and mark all the extant keys of this type as dead.
1180 * Those keys of this type are then destroyed to get rid of their payloads and
1181 * they and their links will be garbage collected as soon as possible.
1182 */
1183void unregister_key_type(struct key_type *ktype)
1184{
1185 down_write(&key_types_sem);
1186 list_del_init(&ktype->link);
1187 downgrade_write(&key_types_sem);
1188 key_gc_keytype(ktype);
1189 pr_notice("Key type %s unregistered\n", ktype->name);
1190 up_read(&key_types_sem);
1191}
1192EXPORT_SYMBOL(unregister_key_type);
1193
1194/*
1195 * Initialise the key management state.
1196 */
1197void __init key_init(void)
1198{
1199 /* allocate a slab in which we can store keys */
1200 key_jar = kmem_cache_create("key_jar", sizeof(struct key),
1201 0, SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
1202
1203 /* add the special key types */
1204 list_add_tail(&key_type_keyring.link, &key_types_list);
1205 list_add_tail(&key_type_dead.link, &key_types_list);
1206 list_add_tail(&key_type_user.link, &key_types_list);
1207 list_add_tail(&key_type_logon.link, &key_types_list);
1208
1209 /* record the root user tracking */
1210 rb_link_node(&root_key_user.node,
1211 NULL,
1212 &key_user_tree.rb_node);
1213
1214 rb_insert_color(&root_key_user.node,
1215 &key_user_tree);
1216}
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 = 1000000; /* root's key count quota */
31unsigned int key_quota_root_maxbytes = 25000000; /* 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 * @restrict_link: Optional link restriction method for new keyrings.
205 *
206 * Allocate a key of the specified type with the attributes given. The key is
207 * returned in an uninstantiated state and the caller needs to instantiate the
208 * key before returning.
209 *
210 * The user's key count quota is updated to reflect the creation of the key and
211 * the user's key data quota has the default for the key type reserved. The
212 * instantiation function should amend this as necessary. If insufficient
213 * quota is available, -EDQUOT will be returned.
214 *
215 * The LSM security modules can prevent a key being created, in which case
216 * -EACCES will be returned.
217 *
218 * Returns a pointer to the new key if successful and an error code otherwise.
219 *
220 * Note that the caller needs to ensure the key type isn't uninstantiated.
221 * Internally this can be done by locking key_types_sem. Externally, this can
222 * be done by either never unregistering the key type, or making sure
223 * key_alloc() calls don't race with module unloading.
224 */
225struct key *key_alloc(struct key_type *type, const char *desc,
226 kuid_t uid, kgid_t gid, const struct cred *cred,
227 key_perm_t perm, unsigned long flags,
228 int (*restrict_link)(struct key *,
229 const struct key_type *,
230 const union key_payload *))
231{
232 struct key_user *user = NULL;
233 struct key *key;
234 size_t desclen, quotalen;
235 int ret;
236
237 key = ERR_PTR(-EINVAL);
238 if (!desc || !*desc)
239 goto error;
240
241 if (type->vet_description) {
242 ret = type->vet_description(desc);
243 if (ret < 0) {
244 key = ERR_PTR(ret);
245 goto error;
246 }
247 }
248
249 desclen = strlen(desc);
250 quotalen = desclen + 1 + type->def_datalen;
251
252 /* get hold of the key tracking for this user */
253 user = key_user_lookup(uid);
254 if (!user)
255 goto no_memory_1;
256
257 /* check that the user's quota permits allocation of another key and
258 * its description */
259 if (!(flags & KEY_ALLOC_NOT_IN_QUOTA)) {
260 unsigned maxkeys = uid_eq(uid, GLOBAL_ROOT_UID) ?
261 key_quota_root_maxkeys : key_quota_maxkeys;
262 unsigned maxbytes = uid_eq(uid, GLOBAL_ROOT_UID) ?
263 key_quota_root_maxbytes : key_quota_maxbytes;
264
265 spin_lock(&user->lock);
266 if (!(flags & KEY_ALLOC_QUOTA_OVERRUN)) {
267 if (user->qnkeys + 1 >= maxkeys ||
268 user->qnbytes + quotalen >= maxbytes ||
269 user->qnbytes + quotalen < user->qnbytes)
270 goto no_quota;
271 }
272
273 user->qnkeys++;
274 user->qnbytes += quotalen;
275 spin_unlock(&user->lock);
276 }
277
278 /* allocate and initialise the key and its description */
279 key = kmem_cache_zalloc(key_jar, GFP_KERNEL);
280 if (!key)
281 goto no_memory_2;
282
283 key->index_key.desc_len = desclen;
284 key->index_key.description = kmemdup(desc, desclen + 1, GFP_KERNEL);
285 if (!key->index_key.description)
286 goto no_memory_3;
287
288 atomic_set(&key->usage, 1);
289 init_rwsem(&key->sem);
290 lockdep_set_class(&key->sem, &type->lock_class);
291 key->index_key.type = type;
292 key->user = user;
293 key->quotalen = quotalen;
294 key->datalen = type->def_datalen;
295 key->uid = uid;
296 key->gid = gid;
297 key->perm = perm;
298 key->restrict_link = restrict_link;
299
300 if (!(flags & KEY_ALLOC_NOT_IN_QUOTA))
301 key->flags |= 1 << KEY_FLAG_IN_QUOTA;
302 if (flags & KEY_ALLOC_BUILT_IN)
303 key->flags |= 1 << KEY_FLAG_BUILTIN;
304
305#ifdef KEY_DEBUGGING
306 key->magic = KEY_DEBUG_MAGIC;
307#endif
308
309 /* let the security module know about the key */
310 ret = security_key_alloc(key, cred, flags);
311 if (ret < 0)
312 goto security_error;
313
314 /* publish the key by giving it a serial number */
315 atomic_inc(&user->nkeys);
316 key_alloc_serial(key);
317
318error:
319 return key;
320
321security_error:
322 kfree(key->description);
323 kmem_cache_free(key_jar, key);
324 if (!(flags & KEY_ALLOC_NOT_IN_QUOTA)) {
325 spin_lock(&user->lock);
326 user->qnkeys--;
327 user->qnbytes -= quotalen;
328 spin_unlock(&user->lock);
329 }
330 key_user_put(user);
331 key = ERR_PTR(ret);
332 goto error;
333
334no_memory_3:
335 kmem_cache_free(key_jar, key);
336no_memory_2:
337 if (!(flags & KEY_ALLOC_NOT_IN_QUOTA)) {
338 spin_lock(&user->lock);
339 user->qnkeys--;
340 user->qnbytes -= quotalen;
341 spin_unlock(&user->lock);
342 }
343 key_user_put(user);
344no_memory_1:
345 key = ERR_PTR(-ENOMEM);
346 goto error;
347
348no_quota:
349 spin_unlock(&user->lock);
350 key_user_put(user);
351 key = ERR_PTR(-EDQUOT);
352 goto error;
353}
354EXPORT_SYMBOL(key_alloc);
355
356/**
357 * key_payload_reserve - Adjust data quota reservation for the key's payload
358 * @key: The key to make the reservation for.
359 * @datalen: The amount of data payload the caller now wants.
360 *
361 * Adjust the amount of the owning user's key data quota that a key reserves.
362 * If the amount is increased, then -EDQUOT may be returned if there isn't
363 * enough free quota available.
364 *
365 * If successful, 0 is returned.
366 */
367int key_payload_reserve(struct key *key, size_t datalen)
368{
369 int delta = (int)datalen - key->datalen;
370 int ret = 0;
371
372 key_check(key);
373
374 /* contemplate the quota adjustment */
375 if (delta != 0 && test_bit(KEY_FLAG_IN_QUOTA, &key->flags)) {
376 unsigned maxbytes = uid_eq(key->user->uid, GLOBAL_ROOT_UID) ?
377 key_quota_root_maxbytes : key_quota_maxbytes;
378
379 spin_lock(&key->user->lock);
380
381 if (delta > 0 &&
382 (key->user->qnbytes + delta >= maxbytes ||
383 key->user->qnbytes + delta < key->user->qnbytes)) {
384 ret = -EDQUOT;
385 }
386 else {
387 key->user->qnbytes += delta;
388 key->quotalen += delta;
389 }
390 spin_unlock(&key->user->lock);
391 }
392
393 /* change the recorded data length if that didn't generate an error */
394 if (ret == 0)
395 key->datalen = datalen;
396
397 return ret;
398}
399EXPORT_SYMBOL(key_payload_reserve);
400
401/*
402 * Instantiate a key and link it into the target keyring atomically. Must be
403 * called with the target keyring's semaphore writelocked. The target key's
404 * semaphore need not be locked as instantiation is serialised by
405 * key_construction_mutex.
406 */
407static int __key_instantiate_and_link(struct key *key,
408 struct key_preparsed_payload *prep,
409 struct key *keyring,
410 struct key *authkey,
411 struct assoc_array_edit **_edit)
412{
413 int ret, awaken;
414
415 key_check(key);
416 key_check(keyring);
417
418 awaken = 0;
419 ret = -EBUSY;
420
421 mutex_lock(&key_construction_mutex);
422
423 /* can't instantiate twice */
424 if (!test_bit(KEY_FLAG_INSTANTIATED, &key->flags)) {
425 /* instantiate the key */
426 ret = key->type->instantiate(key, prep);
427
428 if (ret == 0) {
429 /* mark the key as being instantiated */
430 atomic_inc(&key->user->nikeys);
431 set_bit(KEY_FLAG_INSTANTIATED, &key->flags);
432
433 if (test_and_clear_bit(KEY_FLAG_USER_CONSTRUCT, &key->flags))
434 awaken = 1;
435
436 /* and link it into the destination keyring */
437 if (keyring) {
438 if (test_bit(KEY_FLAG_KEEP, &keyring->flags))
439 set_bit(KEY_FLAG_KEEP, &key->flags);
440
441 __key_link(key, _edit);
442 }
443
444 /* disable the authorisation key */
445 if (authkey)
446 key_revoke(authkey);
447
448 if (prep->expiry != TIME_T_MAX) {
449 key->expiry = prep->expiry;
450 key_schedule_gc(prep->expiry + key_gc_delay);
451 }
452 }
453 }
454
455 mutex_unlock(&key_construction_mutex);
456
457 /* wake up anyone waiting for a key to be constructed */
458 if (awaken)
459 wake_up_bit(&key->flags, KEY_FLAG_USER_CONSTRUCT);
460
461 return ret;
462}
463
464/**
465 * key_instantiate_and_link - Instantiate a key and link it into the keyring.
466 * @key: The key to instantiate.
467 * @data: The data to use to instantiate the keyring.
468 * @datalen: The length of @data.
469 * @keyring: Keyring to create a link in on success (or NULL).
470 * @authkey: The authorisation token permitting instantiation.
471 *
472 * Instantiate a key that's in the uninstantiated state using the provided data
473 * and, if successful, link it in to the destination keyring if one is
474 * supplied.
475 *
476 * If successful, 0 is returned, the authorisation token is revoked and anyone
477 * waiting for the key is woken up. If the key was already instantiated,
478 * -EBUSY will be returned.
479 */
480int key_instantiate_and_link(struct key *key,
481 const void *data,
482 size_t datalen,
483 struct key *keyring,
484 struct key *authkey)
485{
486 struct key_preparsed_payload prep;
487 struct assoc_array_edit *edit;
488 int ret;
489
490 memset(&prep, 0, sizeof(prep));
491 prep.data = data;
492 prep.datalen = datalen;
493 prep.quotalen = key->type->def_datalen;
494 prep.expiry = TIME_T_MAX;
495 if (key->type->preparse) {
496 ret = key->type->preparse(&prep);
497 if (ret < 0)
498 goto error;
499 }
500
501 if (keyring) {
502 if (keyring->restrict_link) {
503 ret = keyring->restrict_link(keyring, key->type,
504 &prep.payload);
505 if (ret < 0)
506 goto error;
507 }
508 ret = __key_link_begin(keyring, &key->index_key, &edit);
509 if (ret < 0)
510 goto error;
511 }
512
513 ret = __key_instantiate_and_link(key, &prep, keyring, authkey, &edit);
514
515 if (keyring)
516 __key_link_end(keyring, &key->index_key, edit);
517
518error:
519 if (key->type->preparse)
520 key->type->free_preparse(&prep);
521 return ret;
522}
523
524EXPORT_SYMBOL(key_instantiate_and_link);
525
526/**
527 * key_reject_and_link - Negatively instantiate a key and link it into the keyring.
528 * @key: The key to instantiate.
529 * @timeout: The timeout on the negative key.
530 * @error: The error to return when the key is hit.
531 * @keyring: Keyring to create a link in on success (or NULL).
532 * @authkey: The authorisation token permitting instantiation.
533 *
534 * Negatively instantiate a key that's in the uninstantiated state and, if
535 * successful, set its timeout and stored error and link it in to the
536 * destination keyring if one is supplied. The key and any links to the key
537 * will be automatically garbage collected after the timeout expires.
538 *
539 * Negative keys are used to rate limit repeated request_key() calls by causing
540 * them to return the stored error code (typically ENOKEY) until the negative
541 * key expires.
542 *
543 * If successful, 0 is returned, the authorisation token is revoked and anyone
544 * waiting for the key is woken up. If the key was already instantiated,
545 * -EBUSY will be returned.
546 */
547int key_reject_and_link(struct key *key,
548 unsigned timeout,
549 unsigned error,
550 struct key *keyring,
551 struct key *authkey)
552{
553 struct assoc_array_edit *edit;
554 struct timespec now;
555 int ret, awaken, link_ret = 0;
556
557 key_check(key);
558 key_check(keyring);
559
560 awaken = 0;
561 ret = -EBUSY;
562
563 if (keyring) {
564 if (keyring->restrict_link)
565 return -EPERM;
566
567 link_ret = __key_link_begin(keyring, &key->index_key, &edit);
568 }
569
570 mutex_lock(&key_construction_mutex);
571
572 /* can't instantiate twice */
573 if (!test_bit(KEY_FLAG_INSTANTIATED, &key->flags)) {
574 /* mark the key as being negatively instantiated */
575 atomic_inc(&key->user->nikeys);
576 key->reject_error = -error;
577 smp_wmb();
578 set_bit(KEY_FLAG_NEGATIVE, &key->flags);
579 set_bit(KEY_FLAG_INSTANTIATED, &key->flags);
580 now = current_kernel_time();
581 key->expiry = now.tv_sec + timeout;
582 key_schedule_gc(key->expiry + key_gc_delay);
583
584 if (test_and_clear_bit(KEY_FLAG_USER_CONSTRUCT, &key->flags))
585 awaken = 1;
586
587 ret = 0;
588
589 /* and link it into the destination keyring */
590 if (keyring && link_ret == 0)
591 __key_link(key, &edit);
592
593 /* disable the authorisation key */
594 if (authkey)
595 key_revoke(authkey);
596 }
597
598 mutex_unlock(&key_construction_mutex);
599
600 if (keyring && link_ret == 0)
601 __key_link_end(keyring, &key->index_key, edit);
602
603 /* wake up anyone waiting for a key to be constructed */
604 if (awaken)
605 wake_up_bit(&key->flags, KEY_FLAG_USER_CONSTRUCT);
606
607 return ret == 0 ? link_ret : ret;
608}
609EXPORT_SYMBOL(key_reject_and_link);
610
611/**
612 * key_put - Discard a reference to a key.
613 * @key: The key to discard a reference from.
614 *
615 * Discard a reference to a key, and when all the references are gone, we
616 * schedule the cleanup task to come and pull it out of the tree in process
617 * context at some later time.
618 */
619void key_put(struct key *key)
620{
621 if (key) {
622 key_check(key);
623
624 if (atomic_dec_and_test(&key->usage))
625 schedule_work(&key_gc_work);
626 }
627}
628EXPORT_SYMBOL(key_put);
629
630/*
631 * Find a key by its serial number.
632 */
633struct key *key_lookup(key_serial_t id)
634{
635 struct rb_node *n;
636 struct key *key;
637
638 spin_lock(&key_serial_lock);
639
640 /* search the tree for the specified key */
641 n = key_serial_tree.rb_node;
642 while (n) {
643 key = rb_entry(n, struct key, serial_node);
644
645 if (id < key->serial)
646 n = n->rb_left;
647 else if (id > key->serial)
648 n = n->rb_right;
649 else
650 goto found;
651 }
652
653not_found:
654 key = ERR_PTR(-ENOKEY);
655 goto error;
656
657found:
658 /* pretend it doesn't exist if it is awaiting deletion */
659 if (atomic_read(&key->usage) == 0)
660 goto not_found;
661
662 /* this races with key_put(), but that doesn't matter since key_put()
663 * doesn't actually change the key
664 */
665 __key_get(key);
666
667error:
668 spin_unlock(&key_serial_lock);
669 return key;
670}
671
672/*
673 * Find and lock the specified key type against removal.
674 *
675 * We return with the sem read-locked if successful. If the type wasn't
676 * available -ENOKEY is returned instead.
677 */
678struct key_type *key_type_lookup(const char *type)
679{
680 struct key_type *ktype;
681
682 down_read(&key_types_sem);
683
684 /* look up the key type to see if it's one of the registered kernel
685 * types */
686 list_for_each_entry(ktype, &key_types_list, link) {
687 if (strcmp(ktype->name, type) == 0)
688 goto found_kernel_type;
689 }
690
691 up_read(&key_types_sem);
692 ktype = ERR_PTR(-ENOKEY);
693
694found_kernel_type:
695 return ktype;
696}
697
698void key_set_timeout(struct key *key, unsigned timeout)
699{
700 struct timespec now;
701 time_t expiry = 0;
702
703 /* make the changes with the locks held to prevent races */
704 down_write(&key->sem);
705
706 if (timeout > 0) {
707 now = current_kernel_time();
708 expiry = now.tv_sec + timeout;
709 }
710
711 key->expiry = expiry;
712 key_schedule_gc(key->expiry + key_gc_delay);
713
714 up_write(&key->sem);
715}
716EXPORT_SYMBOL_GPL(key_set_timeout);
717
718/*
719 * Unlock a key type locked by key_type_lookup().
720 */
721void key_type_put(struct key_type *ktype)
722{
723 up_read(&key_types_sem);
724}
725
726/*
727 * Attempt to update an existing key.
728 *
729 * The key is given to us with an incremented refcount that we need to discard
730 * if we get an error.
731 */
732static inline key_ref_t __key_update(key_ref_t key_ref,
733 struct key_preparsed_payload *prep)
734{
735 struct key *key = key_ref_to_ptr(key_ref);
736 int ret;
737
738 /* need write permission on the key to update it */
739 ret = key_permission(key_ref, KEY_NEED_WRITE);
740 if (ret < 0)
741 goto error;
742
743 ret = -EEXIST;
744 if (!key->type->update)
745 goto error;
746
747 down_write(&key->sem);
748
749 ret = key->type->update(key, prep);
750 if (ret == 0)
751 /* updating a negative key instantiates it */
752 clear_bit(KEY_FLAG_NEGATIVE, &key->flags);
753
754 up_write(&key->sem);
755
756 if (ret < 0)
757 goto error;
758out:
759 return key_ref;
760
761error:
762 key_put(key);
763 key_ref = ERR_PTR(ret);
764 goto out;
765}
766
767/**
768 * key_create_or_update - Update or create and instantiate a key.
769 * @keyring_ref: A pointer to the destination keyring with possession flag.
770 * @type: The type of key.
771 * @description: The searchable description for the key.
772 * @payload: The data to use to instantiate or update the key.
773 * @plen: The length of @payload.
774 * @perm: The permissions mask for a new key.
775 * @flags: The quota flags for a new key.
776 *
777 * Search the destination keyring for a key of the same description and if one
778 * is found, update it, otherwise create and instantiate a new one and create a
779 * link to it from that keyring.
780 *
781 * If perm is KEY_PERM_UNDEF then an appropriate key permissions mask will be
782 * concocted.
783 *
784 * Returns a pointer to the new key if successful, -ENODEV if the key type
785 * wasn't available, -ENOTDIR if the keyring wasn't a keyring, -EACCES if the
786 * caller isn't permitted to modify the keyring or the LSM did not permit
787 * creation of the key.
788 *
789 * On success, the possession flag from the keyring ref will be tacked on to
790 * the key ref before it is returned.
791 */
792key_ref_t key_create_or_update(key_ref_t keyring_ref,
793 const char *type,
794 const char *description,
795 const void *payload,
796 size_t plen,
797 key_perm_t perm,
798 unsigned long flags)
799{
800 struct keyring_index_key index_key = {
801 .description = description,
802 };
803 struct key_preparsed_payload prep;
804 struct assoc_array_edit *edit;
805 const struct cred *cred = current_cred();
806 struct key *keyring, *key = NULL;
807 key_ref_t key_ref;
808 int ret;
809 int (*restrict_link)(struct key *,
810 const struct key_type *,
811 const union key_payload *) = NULL;
812
813 /* look up the key type to see if it's one of the registered kernel
814 * types */
815 index_key.type = key_type_lookup(type);
816 if (IS_ERR(index_key.type)) {
817 key_ref = ERR_PTR(-ENODEV);
818 goto error;
819 }
820
821 key_ref = ERR_PTR(-EINVAL);
822 if (!index_key.type->instantiate ||
823 (!index_key.description && !index_key.type->preparse))
824 goto error_put_type;
825
826 keyring = key_ref_to_ptr(keyring_ref);
827
828 key_check(keyring);
829
830 key_ref = ERR_PTR(-EPERM);
831 if (!(flags & KEY_ALLOC_BYPASS_RESTRICTION))
832 restrict_link = keyring->restrict_link;
833
834 key_ref = ERR_PTR(-ENOTDIR);
835 if (keyring->type != &key_type_keyring)
836 goto error_put_type;
837
838 memset(&prep, 0, sizeof(prep));
839 prep.data = payload;
840 prep.datalen = plen;
841 prep.quotalen = index_key.type->def_datalen;
842 prep.expiry = TIME_T_MAX;
843 if (index_key.type->preparse) {
844 ret = index_key.type->preparse(&prep);
845 if (ret < 0) {
846 key_ref = ERR_PTR(ret);
847 goto error_free_prep;
848 }
849 if (!index_key.description)
850 index_key.description = prep.description;
851 key_ref = ERR_PTR(-EINVAL);
852 if (!index_key.description)
853 goto error_free_prep;
854 }
855 index_key.desc_len = strlen(index_key.description);
856
857 if (restrict_link) {
858 ret = restrict_link(keyring, index_key.type, &prep.payload);
859 if (ret < 0) {
860 key_ref = ERR_PTR(ret);
861 goto error_free_prep;
862 }
863 }
864
865 ret = __key_link_begin(keyring, &index_key, &edit);
866 if (ret < 0) {
867 key_ref = ERR_PTR(ret);
868 goto error_free_prep;
869 }
870
871 /* if we're going to allocate a new key, we're going to have
872 * to modify the keyring */
873 ret = key_permission(keyring_ref, KEY_NEED_WRITE);
874 if (ret < 0) {
875 key_ref = ERR_PTR(ret);
876 goto error_link_end;
877 }
878
879 /* if it's possible to update this type of key, search for an existing
880 * key of the same type and description in the destination keyring and
881 * update that instead if possible
882 */
883 if (index_key.type->update) {
884 key_ref = find_key_to_update(keyring_ref, &index_key);
885 if (key_ref)
886 goto found_matching_key;
887 }
888
889 /* if the client doesn't provide, decide on the permissions we want */
890 if (perm == KEY_PERM_UNDEF) {
891 perm = KEY_POS_VIEW | KEY_POS_SEARCH | KEY_POS_LINK | KEY_POS_SETATTR;
892 perm |= KEY_USR_VIEW;
893
894 if (index_key.type->read)
895 perm |= KEY_POS_READ;
896
897 if (index_key.type == &key_type_keyring ||
898 index_key.type->update)
899 perm |= KEY_POS_WRITE;
900 }
901
902 /* allocate a new key */
903 key = key_alloc(index_key.type, index_key.description,
904 cred->fsuid, cred->fsgid, cred, perm, flags, NULL);
905 if (IS_ERR(key)) {
906 key_ref = ERR_CAST(key);
907 goto error_link_end;
908 }
909
910 /* instantiate it and link it into the target keyring */
911 ret = __key_instantiate_and_link(key, &prep, keyring, NULL, &edit);
912 if (ret < 0) {
913 key_put(key);
914 key_ref = ERR_PTR(ret);
915 goto error_link_end;
916 }
917
918 key_ref = make_key_ref(key, is_key_possessed(keyring_ref));
919
920error_link_end:
921 __key_link_end(keyring, &index_key, edit);
922error_free_prep:
923 if (index_key.type->preparse)
924 index_key.type->free_preparse(&prep);
925error_put_type:
926 key_type_put(index_key.type);
927error:
928 return key_ref;
929
930 found_matching_key:
931 /* we found a matching key, so we're going to try to update it
932 * - we can drop the locks first as we have the key pinned
933 */
934 __key_link_end(keyring, &index_key, edit);
935
936 key_ref = __key_update(key_ref, &prep);
937 goto error_free_prep;
938}
939EXPORT_SYMBOL(key_create_or_update);
940
941/**
942 * key_update - Update a key's contents.
943 * @key_ref: The pointer (plus possession flag) to the key.
944 * @payload: The data to be used to update the key.
945 * @plen: The length of @payload.
946 *
947 * Attempt to update the contents of a key with the given payload data. The
948 * caller must be granted Write permission on the key. Negative keys can be
949 * instantiated by this method.
950 *
951 * Returns 0 on success, -EACCES if not permitted and -EOPNOTSUPP if the key
952 * type does not support updating. The key type may return other errors.
953 */
954int key_update(key_ref_t key_ref, const void *payload, size_t plen)
955{
956 struct key_preparsed_payload prep;
957 struct key *key = key_ref_to_ptr(key_ref);
958 int ret;
959
960 key_check(key);
961
962 /* the key must be writable */
963 ret = key_permission(key_ref, KEY_NEED_WRITE);
964 if (ret < 0)
965 goto error;
966
967 /* attempt to update it if supported */
968 ret = -EOPNOTSUPP;
969 if (!key->type->update)
970 goto error;
971
972 memset(&prep, 0, sizeof(prep));
973 prep.data = payload;
974 prep.datalen = plen;
975 prep.quotalen = key->type->def_datalen;
976 prep.expiry = TIME_T_MAX;
977 if (key->type->preparse) {
978 ret = key->type->preparse(&prep);
979 if (ret < 0)
980 goto error;
981 }
982
983 down_write(&key->sem);
984
985 ret = key->type->update(key, &prep);
986 if (ret == 0)
987 /* updating a negative key instantiates it */
988 clear_bit(KEY_FLAG_NEGATIVE, &key->flags);
989
990 up_write(&key->sem);
991
992error:
993 if (key->type->preparse)
994 key->type->free_preparse(&prep);
995 return ret;
996}
997EXPORT_SYMBOL(key_update);
998
999/**
1000 * key_revoke - Revoke a key.
1001 * @key: The key to be revoked.
1002 *
1003 * Mark a key as being revoked and ask the type to free up its resources. The
1004 * revocation timeout is set and the key and all its links will be
1005 * automatically garbage collected after key_gc_delay amount of time if they
1006 * are not manually dealt with first.
1007 */
1008void key_revoke(struct key *key)
1009{
1010 struct timespec now;
1011 time_t time;
1012
1013 key_check(key);
1014
1015 /* make sure no one's trying to change or use the key when we mark it
1016 * - we tell lockdep that we might nest because we might be revoking an
1017 * authorisation key whilst holding the sem on a key we've just
1018 * instantiated
1019 */
1020 down_write_nested(&key->sem, 1);
1021 if (!test_and_set_bit(KEY_FLAG_REVOKED, &key->flags) &&
1022 key->type->revoke)
1023 key->type->revoke(key);
1024
1025 /* set the death time to no more than the expiry time */
1026 now = current_kernel_time();
1027 time = now.tv_sec;
1028 if (key->revoked_at == 0 || key->revoked_at > time) {
1029 key->revoked_at = time;
1030 key_schedule_gc(key->revoked_at + key_gc_delay);
1031 }
1032
1033 up_write(&key->sem);
1034}
1035EXPORT_SYMBOL(key_revoke);
1036
1037/**
1038 * key_invalidate - Invalidate a key.
1039 * @key: The key to be invalidated.
1040 *
1041 * Mark a key as being invalidated and have it cleaned up immediately. The key
1042 * is ignored by all searches and other operations from this point.
1043 */
1044void key_invalidate(struct key *key)
1045{
1046 kenter("%d", key_serial(key));
1047
1048 key_check(key);
1049
1050 if (!test_bit(KEY_FLAG_INVALIDATED, &key->flags)) {
1051 down_write_nested(&key->sem, 1);
1052 if (!test_and_set_bit(KEY_FLAG_INVALIDATED, &key->flags))
1053 key_schedule_gc_links();
1054 up_write(&key->sem);
1055 }
1056}
1057EXPORT_SYMBOL(key_invalidate);
1058
1059/**
1060 * generic_key_instantiate - Simple instantiation of a key from preparsed data
1061 * @key: The key to be instantiated
1062 * @prep: The preparsed data to load.
1063 *
1064 * Instantiate a key from preparsed data. We assume we can just copy the data
1065 * in directly and clear the old pointers.
1066 *
1067 * This can be pointed to directly by the key type instantiate op pointer.
1068 */
1069int generic_key_instantiate(struct key *key, struct key_preparsed_payload *prep)
1070{
1071 int ret;
1072
1073 pr_devel("==>%s()\n", __func__);
1074
1075 ret = key_payload_reserve(key, prep->quotalen);
1076 if (ret == 0) {
1077 rcu_assign_keypointer(key, prep->payload.data[0]);
1078 key->payload.data[1] = prep->payload.data[1];
1079 key->payload.data[2] = prep->payload.data[2];
1080 key->payload.data[3] = prep->payload.data[3];
1081 prep->payload.data[0] = NULL;
1082 prep->payload.data[1] = NULL;
1083 prep->payload.data[2] = NULL;
1084 prep->payload.data[3] = NULL;
1085 }
1086 pr_devel("<==%s() = %d\n", __func__, ret);
1087 return ret;
1088}
1089EXPORT_SYMBOL(generic_key_instantiate);
1090
1091/**
1092 * register_key_type - Register a type of key.
1093 * @ktype: The new key type.
1094 *
1095 * Register a new key type.
1096 *
1097 * Returns 0 on success or -EEXIST if a type of this name already exists.
1098 */
1099int register_key_type(struct key_type *ktype)
1100{
1101 struct key_type *p;
1102 int ret;
1103
1104 memset(&ktype->lock_class, 0, sizeof(ktype->lock_class));
1105
1106 ret = -EEXIST;
1107 down_write(&key_types_sem);
1108
1109 /* disallow key types with the same name */
1110 list_for_each_entry(p, &key_types_list, link) {
1111 if (strcmp(p->name, ktype->name) == 0)
1112 goto out;
1113 }
1114
1115 /* store the type */
1116 list_add(&ktype->link, &key_types_list);
1117
1118 pr_notice("Key type %s registered\n", ktype->name);
1119 ret = 0;
1120
1121out:
1122 up_write(&key_types_sem);
1123 return ret;
1124}
1125EXPORT_SYMBOL(register_key_type);
1126
1127/**
1128 * unregister_key_type - Unregister a type of key.
1129 * @ktype: The key type.
1130 *
1131 * Unregister a key type and mark all the extant keys of this type as dead.
1132 * Those keys of this type are then destroyed to get rid of their payloads and
1133 * they and their links will be garbage collected as soon as possible.
1134 */
1135void unregister_key_type(struct key_type *ktype)
1136{
1137 down_write(&key_types_sem);
1138 list_del_init(&ktype->link);
1139 downgrade_write(&key_types_sem);
1140 key_gc_keytype(ktype);
1141 pr_notice("Key type %s unregistered\n", ktype->name);
1142 up_read(&key_types_sem);
1143}
1144EXPORT_SYMBOL(unregister_key_type);
1145
1146/*
1147 * Initialise the key management state.
1148 */
1149void __init key_init(void)
1150{
1151 /* allocate a slab in which we can store keys */
1152 key_jar = kmem_cache_create("key_jar", sizeof(struct key),
1153 0, SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
1154
1155 /* add the special key types */
1156 list_add_tail(&key_type_keyring.link, &key_types_list);
1157 list_add_tail(&key_type_dead.link, &key_types_list);
1158 list_add_tail(&key_type_user.link, &key_types_list);
1159 list_add_tail(&key_type_logon.link, &key_types_list);
1160
1161 /* record the root user tracking */
1162 rb_link_node(&root_key_user.node,
1163 NULL,
1164 &key_user_tree.rb_node);
1165
1166 rb_insert_color(&root_key_user.node,
1167 &key_user_tree);
1168}