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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 <linux/user_namespace.h>
22#include "internal.h"
23
24static struct kmem_cache *key_jar;
25struct rb_root key_serial_tree; /* tree of keys indexed by serial */
26DEFINE_SPINLOCK(key_serial_lock);
27
28struct rb_root key_user_tree; /* tree of quota records indexed by UID */
29DEFINE_SPINLOCK(key_user_lock);
30
31unsigned int key_quota_root_maxkeys = 200; /* root's key count quota */
32unsigned int key_quota_root_maxbytes = 20000; /* root's key space quota */
33unsigned int key_quota_maxkeys = 200; /* general key count quota */
34unsigned int key_quota_maxbytes = 20000; /* general key space quota */
35
36static LIST_HEAD(key_types_list);
37static DECLARE_RWSEM(key_types_sem);
38
39static void key_cleanup(struct work_struct *work);
40static DECLARE_WORK(key_cleanup_task, key_cleanup);
41
42/* We serialise key instantiation and link */
43DEFINE_MUTEX(key_construction_mutex);
44
45/* Any key who's type gets unegistered will be re-typed to this */
46static struct key_type key_type_dead = {
47 .name = "dead",
48};
49
50#ifdef KEY_DEBUGGING
51void __key_check(const struct key *key)
52{
53 printk("__key_check: key %p {%08x} should be {%08x}\n",
54 key, key->magic, KEY_DEBUG_MAGIC);
55 BUG();
56}
57#endif
58
59/*
60 * Get the key quota record for a user, allocating a new record if one doesn't
61 * already exist.
62 */
63struct key_user *key_user_lookup(uid_t uid, struct user_namespace *user_ns)
64{
65 struct key_user *candidate = NULL, *user;
66 struct rb_node *parent = NULL;
67 struct rb_node **p;
68
69try_again:
70 p = &key_user_tree.rb_node;
71 spin_lock(&key_user_lock);
72
73 /* search the tree for a user record with a matching UID */
74 while (*p) {
75 parent = *p;
76 user = rb_entry(parent, struct key_user, node);
77
78 if (uid < user->uid)
79 p = &(*p)->rb_left;
80 else if (uid > user->uid)
81 p = &(*p)->rb_right;
82 else if (user_ns < user->user_ns)
83 p = &(*p)->rb_left;
84 else if (user_ns > user->user_ns)
85 p = &(*p)->rb_right;
86 else
87 goto found;
88 }
89
90 /* if we get here, we failed to find a match in the tree */
91 if (!candidate) {
92 /* allocate a candidate user record if we don't already have
93 * one */
94 spin_unlock(&key_user_lock);
95
96 user = NULL;
97 candidate = kmalloc(sizeof(struct key_user), GFP_KERNEL);
98 if (unlikely(!candidate))
99 goto out;
100
101 /* the allocation may have scheduled, so we need to repeat the
102 * search lest someone else added the record whilst we were
103 * asleep */
104 goto try_again;
105 }
106
107 /* if we get here, then the user record still hadn't appeared on the
108 * second pass - so we use the candidate record */
109 atomic_set(&candidate->usage, 1);
110 atomic_set(&candidate->nkeys, 0);
111 atomic_set(&candidate->nikeys, 0);
112 candidate->uid = uid;
113 candidate->user_ns = get_user_ns(user_ns);
114 candidate->qnkeys = 0;
115 candidate->qnbytes = 0;
116 spin_lock_init(&candidate->lock);
117 mutex_init(&candidate->cons_lock);
118
119 rb_link_node(&candidate->node, parent, p);
120 rb_insert_color(&candidate->node, &key_user_tree);
121 spin_unlock(&key_user_lock);
122 user = candidate;
123 goto out;
124
125 /* okay - we found a user record for this UID */
126found:
127 atomic_inc(&user->usage);
128 spin_unlock(&key_user_lock);
129 kfree(candidate);
130out:
131 return user;
132}
133
134/*
135 * Dispose of a user structure
136 */
137void key_user_put(struct key_user *user)
138{
139 if (atomic_dec_and_lock(&user->usage, &key_user_lock)) {
140 rb_erase(&user->node, &key_user_tree);
141 spin_unlock(&key_user_lock);
142 put_user_ns(user->user_ns);
143
144 kfree(user);
145 }
146}
147
148/*
149 * Allocate a serial number for a key. These are assigned randomly to avoid
150 * security issues through covert channel problems.
151 */
152static inline void key_alloc_serial(struct key *key)
153{
154 struct rb_node *parent, **p;
155 struct key *xkey;
156
157 /* propose a random serial number and look for a hole for it in the
158 * serial number tree */
159 do {
160 get_random_bytes(&key->serial, sizeof(key->serial));
161
162 key->serial >>= 1; /* negative numbers are not permitted */
163 } while (key->serial < 3);
164
165 spin_lock(&key_serial_lock);
166
167attempt_insertion:
168 parent = NULL;
169 p = &key_serial_tree.rb_node;
170
171 while (*p) {
172 parent = *p;
173 xkey = rb_entry(parent, struct key, serial_node);
174
175 if (key->serial < xkey->serial)
176 p = &(*p)->rb_left;
177 else if (key->serial > xkey->serial)
178 p = &(*p)->rb_right;
179 else
180 goto serial_exists;
181 }
182
183 /* we've found a suitable hole - arrange for this key to occupy it */
184 rb_link_node(&key->serial_node, parent, p);
185 rb_insert_color(&key->serial_node, &key_serial_tree);
186
187 spin_unlock(&key_serial_lock);
188 return;
189
190 /* we found a key with the proposed serial number - walk the tree from
191 * that point looking for the next unused serial number */
192serial_exists:
193 for (;;) {
194 key->serial++;
195 if (key->serial < 3) {
196 key->serial = 3;
197 goto attempt_insertion;
198 }
199
200 parent = rb_next(parent);
201 if (!parent)
202 goto attempt_insertion;
203
204 xkey = rb_entry(parent, struct key, serial_node);
205 if (key->serial < xkey->serial)
206 goto attempt_insertion;
207 }
208}
209
210/**
211 * key_alloc - Allocate a key of the specified type.
212 * @type: The type of key to allocate.
213 * @desc: The key description to allow the key to be searched out.
214 * @uid: The owner of the new key.
215 * @gid: The group ID for the new key's group permissions.
216 * @cred: The credentials specifying UID namespace.
217 * @perm: The permissions mask of the new key.
218 * @flags: Flags specifying quota properties.
219 *
220 * Allocate a key of the specified type with the attributes given. The key is
221 * returned in an uninstantiated state and the caller needs to instantiate the
222 * key before returning.
223 *
224 * The user's key count quota is updated to reflect the creation of the key and
225 * the user's key data quota has the default for the key type reserved. The
226 * instantiation function should amend this as necessary. If insufficient
227 * quota is available, -EDQUOT will be returned.
228 *
229 * The LSM security modules can prevent a key being created, in which case
230 * -EACCES will be returned.
231 *
232 * Returns a pointer to the new key if successful and an error code otherwise.
233 *
234 * Note that the caller needs to ensure the key type isn't uninstantiated.
235 * Internally this can be done by locking key_types_sem. Externally, this can
236 * be done by either never unregistering the key type, or making sure
237 * key_alloc() calls don't race with module unloading.
238 */
239struct key *key_alloc(struct key_type *type, const char *desc,
240 uid_t uid, gid_t gid, const struct cred *cred,
241 key_perm_t perm, unsigned long flags)
242{
243 struct key_user *user = NULL;
244 struct key *key;
245 size_t desclen, quotalen;
246 int ret;
247
248 key = ERR_PTR(-EINVAL);
249 if (!desc || !*desc)
250 goto error;
251
252 if (type->vet_description) {
253 ret = type->vet_description(desc);
254 if (ret < 0) {
255 key = ERR_PTR(ret);
256 goto error;
257 }
258 }
259
260 desclen = strlen(desc) + 1;
261 quotalen = desclen + type->def_datalen;
262
263 /* get hold of the key tracking for this user */
264 user = key_user_lookup(uid, cred->user->user_ns);
265 if (!user)
266 goto no_memory_1;
267
268 /* check that the user's quota permits allocation of another key and
269 * its description */
270 if (!(flags & KEY_ALLOC_NOT_IN_QUOTA)) {
271 unsigned maxkeys = (uid == 0) ?
272 key_quota_root_maxkeys : key_quota_maxkeys;
273 unsigned maxbytes = (uid == 0) ?
274 key_quota_root_maxbytes : key_quota_maxbytes;
275
276 spin_lock(&user->lock);
277 if (!(flags & KEY_ALLOC_QUOTA_OVERRUN)) {
278 if (user->qnkeys + 1 >= maxkeys ||
279 user->qnbytes + quotalen >= maxbytes ||
280 user->qnbytes + quotalen < user->qnbytes)
281 goto no_quota;
282 }
283
284 user->qnkeys++;
285 user->qnbytes += quotalen;
286 spin_unlock(&user->lock);
287 }
288
289 /* allocate and initialise the key and its description */
290 key = kmem_cache_alloc(key_jar, GFP_KERNEL);
291 if (!key)
292 goto no_memory_2;
293
294 if (desc) {
295 key->description = kmemdup(desc, desclen, GFP_KERNEL);
296 if (!key->description)
297 goto no_memory_3;
298 }
299
300 atomic_set(&key->usage, 1);
301 init_rwsem(&key->sem);
302 key->type = type;
303 key->user = user;
304 key->quotalen = quotalen;
305 key->datalen = type->def_datalen;
306 key->uid = uid;
307 key->gid = gid;
308 key->perm = perm;
309 key->flags = 0;
310 key->expiry = 0;
311 key->payload.data = NULL;
312 key->security = NULL;
313
314 if (!(flags & KEY_ALLOC_NOT_IN_QUOTA))
315 key->flags |= 1 << KEY_FLAG_IN_QUOTA;
316
317 memset(&key->type_data, 0, sizeof(key->type_data));
318
319#ifdef KEY_DEBUGGING
320 key->magic = KEY_DEBUG_MAGIC;
321#endif
322
323 /* let the security module know about the key */
324 ret = security_key_alloc(key, cred, flags);
325 if (ret < 0)
326 goto security_error;
327
328 /* publish the key by giving it a serial number */
329 atomic_inc(&user->nkeys);
330 key_alloc_serial(key);
331
332error:
333 return key;
334
335security_error:
336 kfree(key->description);
337 kmem_cache_free(key_jar, key);
338 if (!(flags & KEY_ALLOC_NOT_IN_QUOTA)) {
339 spin_lock(&user->lock);
340 user->qnkeys--;
341 user->qnbytes -= quotalen;
342 spin_unlock(&user->lock);
343 }
344 key_user_put(user);
345 key = ERR_PTR(ret);
346 goto error;
347
348no_memory_3:
349 kmem_cache_free(key_jar, key);
350no_memory_2:
351 if (!(flags & KEY_ALLOC_NOT_IN_QUOTA)) {
352 spin_lock(&user->lock);
353 user->qnkeys--;
354 user->qnbytes -= quotalen;
355 spin_unlock(&user->lock);
356 }
357 key_user_put(user);
358no_memory_1:
359 key = ERR_PTR(-ENOMEM);
360 goto error;
361
362no_quota:
363 spin_unlock(&user->lock);
364 key_user_put(user);
365 key = ERR_PTR(-EDQUOT);
366 goto error;
367}
368EXPORT_SYMBOL(key_alloc);
369
370/**
371 * key_payload_reserve - Adjust data quota reservation for the key's payload
372 * @key: The key to make the reservation for.
373 * @datalen: The amount of data payload the caller now wants.
374 *
375 * Adjust the amount of the owning user's key data quota that a key reserves.
376 * If the amount is increased, then -EDQUOT may be returned if there isn't
377 * enough free quota available.
378 *
379 * If successful, 0 is returned.
380 */
381int key_payload_reserve(struct key *key, size_t datalen)
382{
383 int delta = (int)datalen - key->datalen;
384 int ret = 0;
385
386 key_check(key);
387
388 /* contemplate the quota adjustment */
389 if (delta != 0 && test_bit(KEY_FLAG_IN_QUOTA, &key->flags)) {
390 unsigned maxbytes = (key->user->uid == 0) ?
391 key_quota_root_maxbytes : key_quota_maxbytes;
392
393 spin_lock(&key->user->lock);
394
395 if (delta > 0 &&
396 (key->user->qnbytes + delta >= maxbytes ||
397 key->user->qnbytes + delta < key->user->qnbytes)) {
398 ret = -EDQUOT;
399 }
400 else {
401 key->user->qnbytes += delta;
402 key->quotalen += delta;
403 }
404 spin_unlock(&key->user->lock);
405 }
406
407 /* change the recorded data length if that didn't generate an error */
408 if (ret == 0)
409 key->datalen = datalen;
410
411 return ret;
412}
413EXPORT_SYMBOL(key_payload_reserve);
414
415/*
416 * Instantiate a key and link it into the target keyring atomically. Must be
417 * called with the target keyring's semaphore writelocked. The target key's
418 * semaphore need not be locked as instantiation is serialised by
419 * key_construction_mutex.
420 */
421static int __key_instantiate_and_link(struct key *key,
422 const void *data,
423 size_t datalen,
424 struct key *keyring,
425 struct key *authkey,
426 unsigned long *_prealloc)
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 (!test_bit(KEY_FLAG_INSTANTIATED, &key->flags)) {
440 /* instantiate the key */
441 ret = key->type->instantiate(key, data, datalen);
442
443 if (ret == 0) {
444 /* mark the key as being instantiated */
445 atomic_inc(&key->user->nikeys);
446 set_bit(KEY_FLAG_INSTANTIATED, &key->flags);
447
448 if (test_and_clear_bit(KEY_FLAG_USER_CONSTRUCT, &key->flags))
449 awaken = 1;
450
451 /* and link it into the destination keyring */
452 if (keyring)
453 __key_link(keyring, key, _prealloc);
454
455 /* disable the authorisation key */
456 if (authkey)
457 key_revoke(authkey);
458 }
459 }
460
461 mutex_unlock(&key_construction_mutex);
462
463 /* wake up anyone waiting for a key to be constructed */
464 if (awaken)
465 wake_up_bit(&key->flags, KEY_FLAG_USER_CONSTRUCT);
466
467 return ret;
468}
469
470/**
471 * key_instantiate_and_link - Instantiate a key and link it into the keyring.
472 * @key: The key to instantiate.
473 * @data: The data to use to instantiate the keyring.
474 * @datalen: The length of @data.
475 * @keyring: Keyring to create a link in on success (or NULL).
476 * @authkey: The authorisation token permitting instantiation.
477 *
478 * Instantiate a key that's in the uninstantiated state using the provided data
479 * and, if successful, link it in to the destination keyring if one is
480 * supplied.
481 *
482 * If successful, 0 is returned, the authorisation token is revoked and anyone
483 * waiting for the key is woken up. If the key was already instantiated,
484 * -EBUSY will be returned.
485 */
486int key_instantiate_and_link(struct key *key,
487 const void *data,
488 size_t datalen,
489 struct key *keyring,
490 struct key *authkey)
491{
492 unsigned long prealloc;
493 int ret;
494
495 if (keyring) {
496 ret = __key_link_begin(keyring, key->type, key->description,
497 &prealloc);
498 if (ret < 0)
499 return ret;
500 }
501
502 ret = __key_instantiate_and_link(key, data, datalen, keyring, authkey,
503 &prealloc);
504
505 if (keyring)
506 __key_link_end(keyring, key->type, prealloc);
507
508 return ret;
509}
510
511EXPORT_SYMBOL(key_instantiate_and_link);
512
513/**
514 * key_reject_and_link - Negatively instantiate a key and link it into the keyring.
515 * @key: The key to instantiate.
516 * @timeout: The timeout on the negative key.
517 * @error: The error to return when the key is hit.
518 * @keyring: Keyring to create a link in on success (or NULL).
519 * @authkey: The authorisation token permitting instantiation.
520 *
521 * Negatively instantiate a key that's in the uninstantiated state and, if
522 * successful, set its timeout and stored error and link it in to the
523 * destination keyring if one is supplied. The key and any links to the key
524 * will be automatically garbage collected after the timeout expires.
525 *
526 * Negative keys are used to rate limit repeated request_key() calls by causing
527 * them to return the stored error code (typically ENOKEY) until the negative
528 * key expires.
529 *
530 * If successful, 0 is returned, the authorisation token is revoked and anyone
531 * waiting for the key is woken up. If the key was already instantiated,
532 * -EBUSY will be returned.
533 */
534int key_reject_and_link(struct key *key,
535 unsigned timeout,
536 unsigned error,
537 struct key *keyring,
538 struct key *authkey)
539{
540 unsigned long prealloc;
541 struct timespec now;
542 int ret, awaken, link_ret = 0;
543
544 key_check(key);
545 key_check(keyring);
546
547 awaken = 0;
548 ret = -EBUSY;
549
550 if (keyring)
551 link_ret = __key_link_begin(keyring, key->type,
552 key->description, &prealloc);
553
554 mutex_lock(&key_construction_mutex);
555
556 /* can't instantiate twice */
557 if (!test_bit(KEY_FLAG_INSTANTIATED, &key->flags)) {
558 /* mark the key as being negatively instantiated */
559 atomic_inc(&key->user->nikeys);
560 set_bit(KEY_FLAG_NEGATIVE, &key->flags);
561 set_bit(KEY_FLAG_INSTANTIATED, &key->flags);
562 key->type_data.reject_error = -error;
563 now = current_kernel_time();
564 key->expiry = now.tv_sec + timeout;
565 key_schedule_gc(key->expiry + key_gc_delay);
566
567 if (test_and_clear_bit(KEY_FLAG_USER_CONSTRUCT, &key->flags))
568 awaken = 1;
569
570 ret = 0;
571
572 /* and link it into the destination keyring */
573 if (keyring && link_ret == 0)
574 __key_link(keyring, key, &prealloc);
575
576 /* disable the authorisation key */
577 if (authkey)
578 key_revoke(authkey);
579 }
580
581 mutex_unlock(&key_construction_mutex);
582
583 if (keyring)
584 __key_link_end(keyring, key->type, prealloc);
585
586 /* wake up anyone waiting for a key to be constructed */
587 if (awaken)
588 wake_up_bit(&key->flags, KEY_FLAG_USER_CONSTRUCT);
589
590 return ret == 0 ? link_ret : ret;
591}
592EXPORT_SYMBOL(key_reject_and_link);
593
594/*
595 * Garbage collect keys in process context so that we don't have to disable
596 * interrupts all over the place.
597 *
598 * key_put() schedules this rather than trying to do the cleanup itself, which
599 * means key_put() doesn't have to sleep.
600 */
601static void key_cleanup(struct work_struct *work)
602{
603 struct rb_node *_n;
604 struct key *key;
605
606go_again:
607 /* look for a dead key in the tree */
608 spin_lock(&key_serial_lock);
609
610 for (_n = rb_first(&key_serial_tree); _n; _n = rb_next(_n)) {
611 key = rb_entry(_n, struct key, serial_node);
612
613 if (atomic_read(&key->usage) == 0)
614 goto found_dead_key;
615 }
616
617 spin_unlock(&key_serial_lock);
618 return;
619
620found_dead_key:
621 /* we found a dead key - once we've removed it from the tree, we can
622 * drop the lock */
623 rb_erase(&key->serial_node, &key_serial_tree);
624 spin_unlock(&key_serial_lock);
625
626 key_check(key);
627
628 security_key_free(key);
629
630 /* deal with the user's key tracking and quota */
631 if (test_bit(KEY_FLAG_IN_QUOTA, &key->flags)) {
632 spin_lock(&key->user->lock);
633 key->user->qnkeys--;
634 key->user->qnbytes -= key->quotalen;
635 spin_unlock(&key->user->lock);
636 }
637
638 atomic_dec(&key->user->nkeys);
639 if (test_bit(KEY_FLAG_INSTANTIATED, &key->flags))
640 atomic_dec(&key->user->nikeys);
641
642 key_user_put(key->user);
643
644 /* now throw away the key memory */
645 if (key->type->destroy)
646 key->type->destroy(key);
647
648 kfree(key->description);
649
650#ifdef KEY_DEBUGGING
651 key->magic = KEY_DEBUG_MAGIC_X;
652#endif
653 kmem_cache_free(key_jar, key);
654
655 /* there may, of course, be more than one key to destroy */
656 goto go_again;
657}
658
659/**
660 * key_put - Discard a reference to a key.
661 * @key: The key to discard a reference from.
662 *
663 * Discard a reference to a key, and when all the references are gone, we
664 * schedule the cleanup task to come and pull it out of the tree in process
665 * context at some later time.
666 */
667void key_put(struct key *key)
668{
669 if (key) {
670 key_check(key);
671
672 if (atomic_dec_and_test(&key->usage))
673 schedule_work(&key_cleanup_task);
674 }
675}
676EXPORT_SYMBOL(key_put);
677
678/*
679 * Find a key by its serial number.
680 */
681struct key *key_lookup(key_serial_t id)
682{
683 struct rb_node *n;
684 struct key *key;
685
686 spin_lock(&key_serial_lock);
687
688 /* search the tree for the specified key */
689 n = key_serial_tree.rb_node;
690 while (n) {
691 key = rb_entry(n, struct key, serial_node);
692
693 if (id < key->serial)
694 n = n->rb_left;
695 else if (id > key->serial)
696 n = n->rb_right;
697 else
698 goto found;
699 }
700
701not_found:
702 key = ERR_PTR(-ENOKEY);
703 goto error;
704
705found:
706 /* pretend it doesn't exist if it is awaiting deletion */
707 if (atomic_read(&key->usage) == 0)
708 goto not_found;
709
710 /* this races with key_put(), but that doesn't matter since key_put()
711 * doesn't actually change the key
712 */
713 atomic_inc(&key->usage);
714
715error:
716 spin_unlock(&key_serial_lock);
717 return key;
718}
719
720/*
721 * Find and lock the specified key type against removal.
722 *
723 * We return with the sem read-locked if successful. If the type wasn't
724 * available -ENOKEY is returned instead.
725 */
726struct key_type *key_type_lookup(const char *type)
727{
728 struct key_type *ktype;
729
730 down_read(&key_types_sem);
731
732 /* look up the key type to see if it's one of the registered kernel
733 * types */
734 list_for_each_entry(ktype, &key_types_list, link) {
735 if (strcmp(ktype->name, type) == 0)
736 goto found_kernel_type;
737 }
738
739 up_read(&key_types_sem);
740 ktype = ERR_PTR(-ENOKEY);
741
742found_kernel_type:
743 return ktype;
744}
745
746/*
747 * Unlock a key type locked by key_type_lookup().
748 */
749void key_type_put(struct key_type *ktype)
750{
751 up_read(&key_types_sem);
752}
753
754/*
755 * Attempt to update an existing key.
756 *
757 * The key is given to us with an incremented refcount that we need to discard
758 * if we get an error.
759 */
760static inline key_ref_t __key_update(key_ref_t key_ref,
761 const void *payload, size_t plen)
762{
763 struct key *key = key_ref_to_ptr(key_ref);
764 int ret;
765
766 /* need write permission on the key to update it */
767 ret = key_permission(key_ref, KEY_WRITE);
768 if (ret < 0)
769 goto error;
770
771 ret = -EEXIST;
772 if (!key->type->update)
773 goto error;
774
775 down_write(&key->sem);
776
777 ret = key->type->update(key, payload, plen);
778 if (ret == 0)
779 /* updating a negative key instantiates it */
780 clear_bit(KEY_FLAG_NEGATIVE, &key->flags);
781
782 up_write(&key->sem);
783
784 if (ret < 0)
785 goto error;
786out:
787 return key_ref;
788
789error:
790 key_put(key);
791 key_ref = ERR_PTR(ret);
792 goto out;
793}
794
795/**
796 * key_create_or_update - Update or create and instantiate a key.
797 * @keyring_ref: A pointer to the destination keyring with possession flag.
798 * @type: The type of key.
799 * @description: The searchable description for the key.
800 * @payload: The data to use to instantiate or update the key.
801 * @plen: The length of @payload.
802 * @perm: The permissions mask for a new key.
803 * @flags: The quota flags for a new key.
804 *
805 * Search the destination keyring for a key of the same description and if one
806 * is found, update it, otherwise create and instantiate a new one and create a
807 * link to it from that keyring.
808 *
809 * If perm is KEY_PERM_UNDEF then an appropriate key permissions mask will be
810 * concocted.
811 *
812 * Returns a pointer to the new key if successful, -ENODEV if the key type
813 * wasn't available, -ENOTDIR if the keyring wasn't a keyring, -EACCES if the
814 * caller isn't permitted to modify the keyring or the LSM did not permit
815 * creation of the key.
816 *
817 * On success, the possession flag from the keyring ref will be tacked on to
818 * the key ref before it is returned.
819 */
820key_ref_t key_create_or_update(key_ref_t keyring_ref,
821 const char *type,
822 const char *description,
823 const void *payload,
824 size_t plen,
825 key_perm_t perm,
826 unsigned long flags)
827{
828 unsigned long prealloc;
829 const struct cred *cred = current_cred();
830 struct key_type *ktype;
831 struct key *keyring, *key = NULL;
832 key_ref_t key_ref;
833 int ret;
834
835 /* look up the key type to see if it's one of the registered kernel
836 * types */
837 ktype = key_type_lookup(type);
838 if (IS_ERR(ktype)) {
839 key_ref = ERR_PTR(-ENODEV);
840 goto error;
841 }
842
843 key_ref = ERR_PTR(-EINVAL);
844 if (!ktype->match || !ktype->instantiate)
845 goto error_2;
846
847 keyring = key_ref_to_ptr(keyring_ref);
848
849 key_check(keyring);
850
851 key_ref = ERR_PTR(-ENOTDIR);
852 if (keyring->type != &key_type_keyring)
853 goto error_2;
854
855 ret = __key_link_begin(keyring, ktype, description, &prealloc);
856 if (ret < 0)
857 goto error_2;
858
859 /* if we're going to allocate a new key, we're going to have
860 * to modify the keyring */
861 ret = key_permission(keyring_ref, KEY_WRITE);
862 if (ret < 0) {
863 key_ref = ERR_PTR(ret);
864 goto error_3;
865 }
866
867 /* if it's possible to update this type of key, search for an existing
868 * key of the same type and description in the destination keyring and
869 * update that instead if possible
870 */
871 if (ktype->update) {
872 key_ref = __keyring_search_one(keyring_ref, ktype, description,
873 0);
874 if (!IS_ERR(key_ref))
875 goto found_matching_key;
876 }
877
878 /* if the client doesn't provide, decide on the permissions we want */
879 if (perm == KEY_PERM_UNDEF) {
880 perm = KEY_POS_VIEW | KEY_POS_SEARCH | KEY_POS_LINK | KEY_POS_SETATTR;
881 perm |= KEY_USR_VIEW | KEY_USR_SEARCH | KEY_USR_LINK | KEY_USR_SETATTR;
882
883 if (ktype->read)
884 perm |= KEY_POS_READ | KEY_USR_READ;
885
886 if (ktype == &key_type_keyring || ktype->update)
887 perm |= KEY_USR_WRITE;
888 }
889
890 /* allocate a new key */
891 key = key_alloc(ktype, description, cred->fsuid, cred->fsgid, cred,
892 perm, flags);
893 if (IS_ERR(key)) {
894 key_ref = ERR_CAST(key);
895 goto error_3;
896 }
897
898 /* instantiate it and link it into the target keyring */
899 ret = __key_instantiate_and_link(key, payload, plen, keyring, NULL,
900 &prealloc);
901 if (ret < 0) {
902 key_put(key);
903 key_ref = ERR_PTR(ret);
904 goto error_3;
905 }
906
907 key_ref = make_key_ref(key, is_key_possessed(keyring_ref));
908
909 error_3:
910 __key_link_end(keyring, ktype, prealloc);
911 error_2:
912 key_type_put(ktype);
913 error:
914 return key_ref;
915
916 found_matching_key:
917 /* we found a matching key, so we're going to try to update it
918 * - we can drop the locks first as we have the key pinned
919 */
920 __key_link_end(keyring, ktype, prealloc);
921 key_type_put(ktype);
922
923 key_ref = __key_update(key_ref, payload, plen);
924 goto error;
925}
926EXPORT_SYMBOL(key_create_or_update);
927
928/**
929 * key_update - Update a key's contents.
930 * @key_ref: The pointer (plus possession flag) to the key.
931 * @payload: The data to be used to update the key.
932 * @plen: The length of @payload.
933 *
934 * Attempt to update the contents of a key with the given payload data. The
935 * caller must be granted Write permission on the key. Negative keys can be
936 * instantiated by this method.
937 *
938 * Returns 0 on success, -EACCES if not permitted and -EOPNOTSUPP if the key
939 * type does not support updating. The key type may return other errors.
940 */
941int key_update(key_ref_t key_ref, const void *payload, size_t plen)
942{
943 struct key *key = key_ref_to_ptr(key_ref);
944 int ret;
945
946 key_check(key);
947
948 /* the key must be writable */
949 ret = key_permission(key_ref, KEY_WRITE);
950 if (ret < 0)
951 goto error;
952
953 /* attempt to update it if supported */
954 ret = -EOPNOTSUPP;
955 if (key->type->update) {
956 down_write(&key->sem);
957
958 ret = key->type->update(key, payload, plen);
959 if (ret == 0)
960 /* updating a negative key instantiates it */
961 clear_bit(KEY_FLAG_NEGATIVE, &key->flags);
962
963 up_write(&key->sem);
964 }
965
966 error:
967 return ret;
968}
969EXPORT_SYMBOL(key_update);
970
971/**
972 * key_revoke - Revoke a key.
973 * @key: The key to be revoked.
974 *
975 * Mark a key as being revoked and ask the type to free up its resources. The
976 * revocation timeout is set and the key and all its links will be
977 * automatically garbage collected after key_gc_delay amount of time if they
978 * are not manually dealt with first.
979 */
980void key_revoke(struct key *key)
981{
982 struct timespec now;
983 time_t time;
984
985 key_check(key);
986
987 /* make sure no one's trying to change or use the key when we mark it
988 * - we tell lockdep that we might nest because we might be revoking an
989 * authorisation key whilst holding the sem on a key we've just
990 * instantiated
991 */
992 down_write_nested(&key->sem, 1);
993 if (!test_and_set_bit(KEY_FLAG_REVOKED, &key->flags) &&
994 key->type->revoke)
995 key->type->revoke(key);
996
997 /* set the death time to no more than the expiry time */
998 now = current_kernel_time();
999 time = now.tv_sec;
1000 if (key->revoked_at == 0 || key->revoked_at > time) {
1001 key->revoked_at = time;
1002 key_schedule_gc(key->revoked_at + key_gc_delay);
1003 }
1004
1005 up_write(&key->sem);
1006}
1007EXPORT_SYMBOL(key_revoke);
1008
1009/**
1010 * register_key_type - Register a type of key.
1011 * @ktype: The new key type.
1012 *
1013 * Register a new key type.
1014 *
1015 * Returns 0 on success or -EEXIST if a type of this name already exists.
1016 */
1017int register_key_type(struct key_type *ktype)
1018{
1019 struct key_type *p;
1020 int ret;
1021
1022 ret = -EEXIST;
1023 down_write(&key_types_sem);
1024
1025 /* disallow key types with the same name */
1026 list_for_each_entry(p, &key_types_list, link) {
1027 if (strcmp(p->name, ktype->name) == 0)
1028 goto out;
1029 }
1030
1031 /* store the type */
1032 list_add(&ktype->link, &key_types_list);
1033 ret = 0;
1034
1035out:
1036 up_write(&key_types_sem);
1037 return ret;
1038}
1039EXPORT_SYMBOL(register_key_type);
1040
1041/**
1042 * unregister_key_type - Unregister a type of key.
1043 * @ktype: The key type.
1044 *
1045 * Unregister a key type and mark all the extant keys of this type as dead.
1046 * Those keys of this type are then destroyed to get rid of their payloads and
1047 * they and their links will be garbage collected as soon as possible.
1048 */
1049void unregister_key_type(struct key_type *ktype)
1050{
1051 struct rb_node *_n;
1052 struct key *key;
1053
1054 down_write(&key_types_sem);
1055
1056 /* withdraw the key type */
1057 list_del_init(&ktype->link);
1058
1059 /* mark all the keys of this type dead */
1060 spin_lock(&key_serial_lock);
1061
1062 for (_n = rb_first(&key_serial_tree); _n; _n = rb_next(_n)) {
1063 key = rb_entry(_n, struct key, serial_node);
1064
1065 if (key->type == ktype) {
1066 key->type = &key_type_dead;
1067 set_bit(KEY_FLAG_DEAD, &key->flags);
1068 }
1069 }
1070
1071 spin_unlock(&key_serial_lock);
1072
1073 /* make sure everyone revalidates their keys */
1074 synchronize_rcu();
1075
1076 /* we should now be able to destroy the payloads of all the keys of
1077 * this type with impunity */
1078 spin_lock(&key_serial_lock);
1079
1080 for (_n = rb_first(&key_serial_tree); _n; _n = rb_next(_n)) {
1081 key = rb_entry(_n, struct key, serial_node);
1082
1083 if (key->type == ktype) {
1084 if (ktype->destroy)
1085 ktype->destroy(key);
1086 memset(&key->payload, KEY_DESTROY, sizeof(key->payload));
1087 }
1088 }
1089
1090 spin_unlock(&key_serial_lock);
1091 up_write(&key_types_sem);
1092
1093 key_schedule_gc(0);
1094}
1095EXPORT_SYMBOL(unregister_key_type);
1096
1097/*
1098 * Initialise the key management state.
1099 */
1100void __init key_init(void)
1101{
1102 /* allocate a slab in which we can store keys */
1103 key_jar = kmem_cache_create("key_jar", sizeof(struct key),
1104 0, SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
1105
1106 /* add the special key types */
1107 list_add_tail(&key_type_keyring.link, &key_types_list);
1108 list_add_tail(&key_type_dead.link, &key_types_list);
1109 list_add_tail(&key_type_user.link, &key_types_list);
1110
1111 /* record the root user tracking */
1112 rb_link_node(&root_key_user.node,
1113 NULL,
1114 &key_user_tree.rb_node);
1115
1116 rb_insert_color(&root_key_user.node,
1117 &key_user_tree);
1118}
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
234 key = ERR_PTR(-EINVAL);
235 if (!desc || !*desc)
236 goto error;
237
238 if (type->vet_description) {
239 ret = type->vet_description(desc);
240 if (ret < 0) {
241 key = ERR_PTR(ret);
242 goto error;
243 }
244 }
245
246 desclen = strlen(desc);
247 quotalen = desclen + 1 + type->def_datalen;
248
249 /* get hold of the key tracking for this user */
250 user = key_user_lookup(uid);
251 if (!user)
252 goto no_memory_1;
253
254 /* check that the user's quota permits allocation of another key and
255 * its description */
256 if (!(flags & KEY_ALLOC_NOT_IN_QUOTA)) {
257 unsigned maxkeys = uid_eq(uid, GLOBAL_ROOT_UID) ?
258 key_quota_root_maxkeys : key_quota_maxkeys;
259 unsigned maxbytes = uid_eq(uid, GLOBAL_ROOT_UID) ?
260 key_quota_root_maxbytes : key_quota_maxbytes;
261
262 spin_lock(&user->lock);
263 if (!(flags & KEY_ALLOC_QUOTA_OVERRUN)) {
264 if (user->qnkeys + 1 > maxkeys ||
265 user->qnbytes + quotalen > maxbytes ||
266 user->qnbytes + quotalen < user->qnbytes)
267 goto no_quota;
268 }
269
270 user->qnkeys++;
271 user->qnbytes += quotalen;
272 spin_unlock(&user->lock);
273 }
274
275 /* allocate and initialise the key and its description */
276 key = kmem_cache_zalloc(key_jar, GFP_KERNEL);
277 if (!key)
278 goto no_memory_2;
279
280 key->index_key.desc_len = desclen;
281 key->index_key.description = kmemdup(desc, desclen + 1, GFP_KERNEL);
282 if (!key->index_key.description)
283 goto no_memory_3;
284 key->index_key.type = type;
285 key_set_index_key(&key->index_key);
286
287 refcount_set(&key->usage, 1);
288 init_rwsem(&key->sem);
289 lockdep_set_class(&key->sem, &type->lock_class);
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 key->expiry = TIME64_MAX;
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 if (flags & KEY_ALLOC_SET_KEEP)
307 key->flags |= 1 << KEY_FLAG_KEEP;
308
309#ifdef KEY_DEBUGGING
310 key->magic = KEY_DEBUG_MAGIC;
311#endif
312
313 /* let the security module know about the key */
314 ret = security_key_alloc(key, cred, flags);
315 if (ret < 0)
316 goto security_error;
317
318 /* publish the key by giving it a serial number */
319 refcount_inc(&key->domain_tag->usage);
320 atomic_inc(&user->nkeys);
321 key_alloc_serial(key);
322
323error:
324 return key;
325
326security_error:
327 kfree(key->description);
328 kmem_cache_free(key_jar, key);
329 if (!(flags & KEY_ALLOC_NOT_IN_QUOTA)) {
330 spin_lock(&user->lock);
331 user->qnkeys--;
332 user->qnbytes -= quotalen;
333 spin_unlock(&user->lock);
334 }
335 key_user_put(user);
336 key = ERR_PTR(ret);
337 goto error;
338
339no_memory_3:
340 kmem_cache_free(key_jar, key);
341no_memory_2:
342 if (!(flags & KEY_ALLOC_NOT_IN_QUOTA)) {
343 spin_lock(&user->lock);
344 user->qnkeys--;
345 user->qnbytes -= quotalen;
346 spin_unlock(&user->lock);
347 }
348 key_user_put(user);
349no_memory_1:
350 key = ERR_PTR(-ENOMEM);
351 goto error;
352
353no_quota:
354 spin_unlock(&user->lock);
355 key_user_put(user);
356 key = ERR_PTR(-EDQUOT);
357 goto error;
358}
359EXPORT_SYMBOL(key_alloc);
360
361/**
362 * key_payload_reserve - Adjust data quota reservation for the key's payload
363 * @key: The key to make the reservation for.
364 * @datalen: The amount of data payload the caller now wants.
365 *
366 * Adjust the amount of the owning user's key data quota that a key reserves.
367 * If the amount is increased, then -EDQUOT may be returned if there isn't
368 * enough free quota available.
369 *
370 * If successful, 0 is returned.
371 */
372int key_payload_reserve(struct key *key, size_t datalen)
373{
374 int delta = (int)datalen - key->datalen;
375 int ret = 0;
376
377 key_check(key);
378
379 /* contemplate the quota adjustment */
380 if (delta != 0 && test_bit(KEY_FLAG_IN_QUOTA, &key->flags)) {
381 unsigned maxbytes = uid_eq(key->user->uid, GLOBAL_ROOT_UID) ?
382 key_quota_root_maxbytes : key_quota_maxbytes;
383
384 spin_lock(&key->user->lock);
385
386 if (delta > 0 &&
387 (key->user->qnbytes + delta > maxbytes ||
388 key->user->qnbytes + delta < key->user->qnbytes)) {
389 ret = -EDQUOT;
390 }
391 else {
392 key->user->qnbytes += delta;
393 key->quotalen += delta;
394 }
395 spin_unlock(&key->user->lock);
396 }
397
398 /* change the recorded data length if that didn't generate an error */
399 if (ret == 0)
400 key->datalen = datalen;
401
402 return ret;
403}
404EXPORT_SYMBOL(key_payload_reserve);
405
406/*
407 * Change the key state to being instantiated.
408 */
409static void mark_key_instantiated(struct key *key, int reject_error)
410{
411 /* Commit the payload before setting the state; barrier versus
412 * key_read_state().
413 */
414 smp_store_release(&key->state,
415 (reject_error < 0) ? reject_error : KEY_IS_POSITIVE);
416}
417
418/*
419 * Instantiate a key and link it into the target keyring atomically. Must be
420 * called with the target keyring's semaphore writelocked. The target key's
421 * semaphore need not be locked as instantiation is serialised by
422 * key_construction_mutex.
423 */
424static int __key_instantiate_and_link(struct key *key,
425 struct key_preparsed_payload *prep,
426 struct key *keyring,
427 struct key *authkey,
428 struct assoc_array_edit **_edit)
429{
430 int ret, awaken;
431
432 key_check(key);
433 key_check(keyring);
434
435 awaken = 0;
436 ret = -EBUSY;
437
438 mutex_lock(&key_construction_mutex);
439
440 /* can't instantiate twice */
441 if (key->state == KEY_IS_UNINSTANTIATED) {
442 /* instantiate the key */
443 ret = key->type->instantiate(key, prep);
444
445 if (ret == 0) {
446 /* mark the key as being instantiated */
447 atomic_inc(&key->user->nikeys);
448 mark_key_instantiated(key, 0);
449 notify_key(key, NOTIFY_KEY_INSTANTIATED, 0);
450
451 if (test_and_clear_bit(KEY_FLAG_USER_CONSTRUCT, &key->flags))
452 awaken = 1;
453
454 /* and link it into the destination keyring */
455 if (keyring) {
456 if (test_bit(KEY_FLAG_KEEP, &keyring->flags))
457 set_bit(KEY_FLAG_KEEP, &key->flags);
458
459 __key_link(keyring, key, _edit);
460 }
461
462 /* disable the authorisation key */
463 if (authkey)
464 key_invalidate(authkey);
465
466 if (prep->expiry != TIME64_MAX)
467 key_set_expiry(key, prep->expiry);
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.orig_description = key->description;
508 prep.data = data;
509 prep.datalen = datalen;
510 prep.quotalen = key->type->def_datalen;
511 prep.expiry = TIME64_MAX;
512 if (key->type->preparse) {
513 ret = key->type->preparse(&prep);
514 if (ret < 0)
515 goto error;
516 }
517
518 if (keyring) {
519 ret = __key_link_lock(keyring, &key->index_key);
520 if (ret < 0)
521 goto error;
522
523 ret = __key_link_begin(keyring, &key->index_key, &edit);
524 if (ret < 0)
525 goto error_link_end;
526
527 if (keyring->restrict_link && keyring->restrict_link->check) {
528 struct key_restriction *keyres = keyring->restrict_link;
529
530 ret = keyres->check(keyring, key->type, &prep.payload,
531 keyres->key);
532 if (ret < 0)
533 goto error_link_end;
534 }
535 }
536
537 ret = __key_instantiate_and_link(key, &prep, keyring, authkey, &edit);
538
539error_link_end:
540 if (keyring)
541 __key_link_end(keyring, &key->index_key, edit);
542
543error:
544 if (key->type->preparse)
545 key->type->free_preparse(&prep);
546 return ret;
547}
548
549EXPORT_SYMBOL(key_instantiate_and_link);
550
551/**
552 * key_reject_and_link - Negatively instantiate a key and link it into the keyring.
553 * @key: The key to instantiate.
554 * @timeout: The timeout on the negative key.
555 * @error: The error to return when the key is hit.
556 * @keyring: Keyring to create a link in on success (or NULL).
557 * @authkey: The authorisation token permitting instantiation.
558 *
559 * Negatively instantiate a key that's in the uninstantiated state and, if
560 * successful, set its timeout and stored error and link it in to the
561 * destination keyring if one is supplied. The key and any links to the key
562 * will be automatically garbage collected after the timeout expires.
563 *
564 * Negative keys are used to rate limit repeated request_key() calls by causing
565 * them to return the stored error code (typically ENOKEY) until the negative
566 * key expires.
567 *
568 * If successful, 0 is returned, the authorisation token is revoked and anyone
569 * waiting for the key is woken up. If the key was already instantiated,
570 * -EBUSY will be returned.
571 */
572int key_reject_and_link(struct key *key,
573 unsigned timeout,
574 unsigned error,
575 struct key *keyring,
576 struct key *authkey)
577{
578 struct assoc_array_edit *edit = NULL;
579 int ret, awaken, link_ret = 0;
580
581 key_check(key);
582 key_check(keyring);
583
584 awaken = 0;
585 ret = -EBUSY;
586
587 if (keyring) {
588 if (keyring->restrict_link)
589 return -EPERM;
590
591 link_ret = __key_link_lock(keyring, &key->index_key);
592 if (link_ret == 0) {
593 link_ret = __key_link_begin(keyring, &key->index_key, &edit);
594 if (link_ret < 0)
595 __key_link_end(keyring, &key->index_key, edit);
596 }
597 }
598
599 mutex_lock(&key_construction_mutex);
600
601 /* can't instantiate twice */
602 if (key->state == KEY_IS_UNINSTANTIATED) {
603 /* mark the key as being negatively instantiated */
604 atomic_inc(&key->user->nikeys);
605 mark_key_instantiated(key, -error);
606 notify_key(key, NOTIFY_KEY_INSTANTIATED, -error);
607 key_set_expiry(key, ktime_get_real_seconds() + timeout);
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}
693EXPORT_SYMBOL(key_lookup);
694
695/*
696 * Find and lock the specified key type against removal.
697 *
698 * We return with the sem read-locked if successful. If the type wasn't
699 * available -ENOKEY is returned instead.
700 */
701struct key_type *key_type_lookup(const char *type)
702{
703 struct key_type *ktype;
704
705 down_read(&key_types_sem);
706
707 /* look up the key type to see if it's one of the registered kernel
708 * types */
709 list_for_each_entry(ktype, &key_types_list, link) {
710 if (strcmp(ktype->name, type) == 0)
711 goto found_kernel_type;
712 }
713
714 up_read(&key_types_sem);
715 ktype = ERR_PTR(-ENOKEY);
716
717found_kernel_type:
718 return ktype;
719}
720
721void key_set_timeout(struct key *key, unsigned timeout)
722{
723 time64_t expiry = TIME64_MAX;
724
725 /* make the changes with the locks held to prevent races */
726 down_write(&key->sem);
727
728 if (timeout > 0)
729 expiry = ktime_get_real_seconds() + timeout;
730 key_set_expiry(key, expiry);
731
732 up_write(&key->sem);
733}
734EXPORT_SYMBOL_GPL(key_set_timeout);
735
736/*
737 * Unlock a key type locked by key_type_lookup().
738 */
739void key_type_put(struct key_type *ktype)
740{
741 up_read(&key_types_sem);
742}
743
744/*
745 * Attempt to update an existing key.
746 *
747 * The key is given to us with an incremented refcount that we need to discard
748 * if we get an error.
749 */
750static inline key_ref_t __key_update(key_ref_t key_ref,
751 struct key_preparsed_payload *prep)
752{
753 struct key *key = key_ref_to_ptr(key_ref);
754 int ret;
755
756 /* need write permission on the key to update it */
757 ret = key_permission(key_ref, KEY_NEED_WRITE);
758 if (ret < 0)
759 goto error;
760
761 ret = -EEXIST;
762 if (!key->type->update)
763 goto error;
764
765 down_write(&key->sem);
766
767 ret = key->type->update(key, prep);
768 if (ret == 0) {
769 /* Updating a negative key positively instantiates it */
770 mark_key_instantiated(key, 0);
771 notify_key(key, NOTIFY_KEY_UPDATED, 0);
772 }
773
774 up_write(&key->sem);
775
776 if (ret < 0)
777 goto error;
778out:
779 return key_ref;
780
781error:
782 key_put(key);
783 key_ref = ERR_PTR(ret);
784 goto out;
785}
786
787/*
788 * Create or potentially update a key. The combined logic behind
789 * key_create_or_update() and key_create()
790 */
791static key_ref_t __key_create_or_update(key_ref_t keyring_ref,
792 const char *type,
793 const char *description,
794 const void *payload,
795 size_t plen,
796 key_perm_t perm,
797 unsigned long flags,
798 bool allow_update)
799{
800 struct keyring_index_key index_key = {
801 .description = description,
802 };
803 struct key_preparsed_payload prep;
804 struct assoc_array_edit *edit = NULL;
805 const struct cred *cred = current_cred();
806 struct key *keyring, *key = NULL;
807 key_ref_t key_ref;
808 int ret;
809 struct key_restriction *restrict_link = NULL;
810
811 /* look up the key type to see if it's one of the registered kernel
812 * types */
813 index_key.type = key_type_lookup(type);
814 if (IS_ERR(index_key.type)) {
815 key_ref = ERR_PTR(-ENODEV);
816 goto error;
817 }
818
819 key_ref = ERR_PTR(-EINVAL);
820 if (!index_key.type->instantiate ||
821 (!index_key.description && !index_key.type->preparse))
822 goto error_put_type;
823
824 keyring = key_ref_to_ptr(keyring_ref);
825
826 key_check(keyring);
827
828 if (!(flags & KEY_ALLOC_BYPASS_RESTRICTION))
829 restrict_link = keyring->restrict_link;
830
831 key_ref = ERR_PTR(-ENOTDIR);
832 if (keyring->type != &key_type_keyring)
833 goto error_put_type;
834
835 memset(&prep, 0, sizeof(prep));
836 prep.orig_description = description;
837 prep.data = payload;
838 prep.datalen = plen;
839 prep.quotalen = index_key.type->def_datalen;
840 prep.expiry = TIME64_MAX;
841 if (index_key.type->preparse) {
842 ret = index_key.type->preparse(&prep);
843 if (ret < 0) {
844 key_ref = ERR_PTR(ret);
845 goto error_free_prep;
846 }
847 if (!index_key.description)
848 index_key.description = prep.description;
849 key_ref = ERR_PTR(-EINVAL);
850 if (!index_key.description)
851 goto error_free_prep;
852 }
853 index_key.desc_len = strlen(index_key.description);
854 key_set_index_key(&index_key);
855
856 ret = __key_link_lock(keyring, &index_key);
857 if (ret < 0) {
858 key_ref = ERR_PTR(ret);
859 goto error_free_prep;
860 }
861
862 ret = __key_link_begin(keyring, &index_key, &edit);
863 if (ret < 0) {
864 key_ref = ERR_PTR(ret);
865 goto error_link_end;
866 }
867
868 if (restrict_link && restrict_link->check) {
869 ret = restrict_link->check(keyring, index_key.type,
870 &prep.payload, restrict_link->key);
871 if (ret < 0) {
872 key_ref = ERR_PTR(ret);
873 goto error_link_end;
874 }
875 }
876
877 /* if we're going to allocate a new key, we're going to have
878 * to modify the keyring */
879 ret = key_permission(keyring_ref, KEY_NEED_WRITE);
880 if (ret < 0) {
881 key_ref = ERR_PTR(ret);
882 goto error_link_end;
883 }
884
885 /* if it's requested and possible to update this type of key, search
886 * for an existing key of the same type and description in the
887 * destination keyring and update that instead if possible
888 */
889 if (allow_update) {
890 if (index_key.type->update) {
891 key_ref = find_key_to_update(keyring_ref, &index_key);
892 if (key_ref)
893 goto found_matching_key;
894 }
895 } else {
896 key_ref = find_key_to_update(keyring_ref, &index_key);
897 if (key_ref) {
898 key_ref_put(key_ref);
899 key_ref = ERR_PTR(-EEXIST);
900 goto error_link_end;
901 }
902 }
903
904 /* if the client doesn't provide, decide on the permissions we want */
905 if (perm == KEY_PERM_UNDEF) {
906 perm = KEY_POS_VIEW | KEY_POS_SEARCH | KEY_POS_LINK | KEY_POS_SETATTR;
907 perm |= KEY_USR_VIEW;
908
909 if (index_key.type->read)
910 perm |= KEY_POS_READ;
911
912 if (index_key.type == &key_type_keyring ||
913 index_key.type->update)
914 perm |= KEY_POS_WRITE;
915 }
916
917 /* allocate a new key */
918 key = key_alloc(index_key.type, index_key.description,
919 cred->fsuid, cred->fsgid, cred, perm, flags, NULL);
920 if (IS_ERR(key)) {
921 key_ref = ERR_CAST(key);
922 goto error_link_end;
923 }
924
925 /* instantiate it and link it into the target keyring */
926 ret = __key_instantiate_and_link(key, &prep, keyring, NULL, &edit);
927 if (ret < 0) {
928 key_put(key);
929 key_ref = ERR_PTR(ret);
930 goto error_link_end;
931 }
932
933 security_key_post_create_or_update(keyring, key, payload, plen, flags,
934 true);
935
936 key_ref = make_key_ref(key, is_key_possessed(keyring_ref));
937
938error_link_end:
939 __key_link_end(keyring, &index_key, edit);
940error_free_prep:
941 if (index_key.type->preparse)
942 index_key.type->free_preparse(&prep);
943error_put_type:
944 key_type_put(index_key.type);
945error:
946 return key_ref;
947
948 found_matching_key:
949 /* we found a matching key, so we're going to try to update it
950 * - we can drop the locks first as we have the key pinned
951 */
952 __key_link_end(keyring, &index_key, edit);
953
954 key = key_ref_to_ptr(key_ref);
955 if (test_bit(KEY_FLAG_USER_CONSTRUCT, &key->flags)) {
956 ret = wait_for_key_construction(key, true);
957 if (ret < 0) {
958 key_ref_put(key_ref);
959 key_ref = ERR_PTR(ret);
960 goto error_free_prep;
961 }
962 }
963
964 key_ref = __key_update(key_ref, &prep);
965
966 if (!IS_ERR(key_ref))
967 security_key_post_create_or_update(keyring, key, payload, plen,
968 flags, false);
969
970 goto error_free_prep;
971}
972
973/**
974 * key_create_or_update - Update or create and instantiate a key.
975 * @keyring_ref: A pointer to the destination keyring with possession flag.
976 * @type: The type of key.
977 * @description: The searchable description for the key.
978 * @payload: The data to use to instantiate or update the key.
979 * @plen: The length of @payload.
980 * @perm: The permissions mask for a new key.
981 * @flags: The quota flags for a new key.
982 *
983 * Search the destination keyring for a key of the same description and if one
984 * is found, update it, otherwise create and instantiate a new one and create a
985 * link to it from that keyring.
986 *
987 * If perm is KEY_PERM_UNDEF then an appropriate key permissions mask will be
988 * concocted.
989 *
990 * Returns a pointer to the new key if successful, -ENODEV if the key type
991 * wasn't available, -ENOTDIR if the keyring wasn't a keyring, -EACCES if the
992 * caller isn't permitted to modify the keyring or the LSM did not permit
993 * creation of the key.
994 *
995 * On success, the possession flag from the keyring ref will be tacked on to
996 * the key ref before it is returned.
997 */
998key_ref_t key_create_or_update(key_ref_t keyring_ref,
999 const char *type,
1000 const char *description,
1001 const void *payload,
1002 size_t plen,
1003 key_perm_t perm,
1004 unsigned long flags)
1005{
1006 return __key_create_or_update(keyring_ref, type, description, payload,
1007 plen, perm, flags, true);
1008}
1009EXPORT_SYMBOL(key_create_or_update);
1010
1011/**
1012 * key_create - Create and instantiate a key.
1013 * @keyring_ref: A pointer to the destination keyring with possession flag.
1014 * @type: The type of key.
1015 * @description: The searchable description for the key.
1016 * @payload: The data to use to instantiate or update the key.
1017 * @plen: The length of @payload.
1018 * @perm: The permissions mask for a new key.
1019 * @flags: The quota flags for a new key.
1020 *
1021 * Create and instantiate a new key and link to it from the destination keyring.
1022 *
1023 * If perm is KEY_PERM_UNDEF then an appropriate key permissions mask will be
1024 * concocted.
1025 *
1026 * Returns a pointer to the new key if successful, -EEXIST if a key with the
1027 * same description already exists, -ENODEV if the key type wasn't available,
1028 * -ENOTDIR if the keyring wasn't a keyring, -EACCES if the caller isn't
1029 * permitted to modify the keyring or the LSM did not permit creation of the
1030 * key.
1031 *
1032 * On success, the possession flag from the keyring ref will be tacked on to
1033 * the key ref before it is returned.
1034 */
1035key_ref_t key_create(key_ref_t keyring_ref,
1036 const char *type,
1037 const char *description,
1038 const void *payload,
1039 size_t plen,
1040 key_perm_t perm,
1041 unsigned long flags)
1042{
1043 return __key_create_or_update(keyring_ref, type, description, payload,
1044 plen, perm, flags, false);
1045}
1046EXPORT_SYMBOL(key_create);
1047
1048/**
1049 * key_update - Update a key's contents.
1050 * @key_ref: The pointer (plus possession flag) to the key.
1051 * @payload: The data to be used to update the key.
1052 * @plen: The length of @payload.
1053 *
1054 * Attempt to update the contents of a key with the given payload data. The
1055 * caller must be granted Write permission on the key. Negative keys can be
1056 * instantiated by this method.
1057 *
1058 * Returns 0 on success, -EACCES if not permitted and -EOPNOTSUPP if the key
1059 * type does not support updating. The key type may return other errors.
1060 */
1061int key_update(key_ref_t key_ref, const void *payload, size_t plen)
1062{
1063 struct key_preparsed_payload prep;
1064 struct key *key = key_ref_to_ptr(key_ref);
1065 int ret;
1066
1067 key_check(key);
1068
1069 /* the key must be writable */
1070 ret = key_permission(key_ref, KEY_NEED_WRITE);
1071 if (ret < 0)
1072 return ret;
1073
1074 /* attempt to update it if supported */
1075 if (!key->type->update)
1076 return -EOPNOTSUPP;
1077
1078 memset(&prep, 0, sizeof(prep));
1079 prep.data = payload;
1080 prep.datalen = plen;
1081 prep.quotalen = key->type->def_datalen;
1082 prep.expiry = TIME64_MAX;
1083 if (key->type->preparse) {
1084 ret = key->type->preparse(&prep);
1085 if (ret < 0)
1086 goto error;
1087 }
1088
1089 down_write(&key->sem);
1090
1091 ret = key->type->update(key, &prep);
1092 if (ret == 0) {
1093 /* Updating a negative key positively instantiates it */
1094 mark_key_instantiated(key, 0);
1095 notify_key(key, NOTIFY_KEY_UPDATED, 0);
1096 }
1097
1098 up_write(&key->sem);
1099
1100error:
1101 if (key->type->preparse)
1102 key->type->free_preparse(&prep);
1103 return ret;
1104}
1105EXPORT_SYMBOL(key_update);
1106
1107/**
1108 * key_revoke - Revoke a key.
1109 * @key: The key to be revoked.
1110 *
1111 * Mark a key as being revoked and ask the type to free up its resources. The
1112 * revocation timeout is set and the key and all its links will be
1113 * automatically garbage collected after key_gc_delay amount of time if they
1114 * are not manually dealt with first.
1115 */
1116void key_revoke(struct key *key)
1117{
1118 time64_t time;
1119
1120 key_check(key);
1121
1122 /* make sure no one's trying to change or use the key when we mark it
1123 * - we tell lockdep that we might nest because we might be revoking an
1124 * authorisation key whilst holding the sem on a key we've just
1125 * instantiated
1126 */
1127 down_write_nested(&key->sem, 1);
1128 if (!test_and_set_bit(KEY_FLAG_REVOKED, &key->flags)) {
1129 notify_key(key, NOTIFY_KEY_REVOKED, 0);
1130 if (key->type->revoke)
1131 key->type->revoke(key);
1132
1133 /* set the death time to no more than the expiry time */
1134 time = ktime_get_real_seconds();
1135 if (key->revoked_at == 0 || key->revoked_at > time) {
1136 key->revoked_at = time;
1137 key_schedule_gc(key->revoked_at + key_gc_delay);
1138 }
1139 }
1140
1141 up_write(&key->sem);
1142}
1143EXPORT_SYMBOL(key_revoke);
1144
1145/**
1146 * key_invalidate - Invalidate a key.
1147 * @key: The key to be invalidated.
1148 *
1149 * Mark a key as being invalidated and have it cleaned up immediately. The key
1150 * is ignored by all searches and other operations from this point.
1151 */
1152void key_invalidate(struct key *key)
1153{
1154 kenter("%d", key_serial(key));
1155
1156 key_check(key);
1157
1158 if (!test_bit(KEY_FLAG_INVALIDATED, &key->flags)) {
1159 down_write_nested(&key->sem, 1);
1160 if (!test_and_set_bit(KEY_FLAG_INVALIDATED, &key->flags)) {
1161 notify_key(key, NOTIFY_KEY_INVALIDATED, 0);
1162 key_schedule_gc_links();
1163 }
1164 up_write(&key->sem);
1165 }
1166}
1167EXPORT_SYMBOL(key_invalidate);
1168
1169/**
1170 * generic_key_instantiate - Simple instantiation of a key from preparsed data
1171 * @key: The key to be instantiated
1172 * @prep: The preparsed data to load.
1173 *
1174 * Instantiate a key from preparsed data. We assume we can just copy the data
1175 * in directly and clear the old pointers.
1176 *
1177 * This can be pointed to directly by the key type instantiate op pointer.
1178 */
1179int generic_key_instantiate(struct key *key, struct key_preparsed_payload *prep)
1180{
1181 int ret;
1182
1183 pr_devel("==>%s()\n", __func__);
1184
1185 ret = key_payload_reserve(key, prep->quotalen);
1186 if (ret == 0) {
1187 rcu_assign_keypointer(key, prep->payload.data[0]);
1188 key->payload.data[1] = prep->payload.data[1];
1189 key->payload.data[2] = prep->payload.data[2];
1190 key->payload.data[3] = prep->payload.data[3];
1191 prep->payload.data[0] = NULL;
1192 prep->payload.data[1] = NULL;
1193 prep->payload.data[2] = NULL;
1194 prep->payload.data[3] = NULL;
1195 }
1196 pr_devel("<==%s() = %d\n", __func__, ret);
1197 return ret;
1198}
1199EXPORT_SYMBOL(generic_key_instantiate);
1200
1201/**
1202 * register_key_type - Register a type of key.
1203 * @ktype: The new key type.
1204 *
1205 * Register a new key type.
1206 *
1207 * Returns 0 on success or -EEXIST if a type of this name already exists.
1208 */
1209int register_key_type(struct key_type *ktype)
1210{
1211 struct key_type *p;
1212 int ret;
1213
1214 memset(&ktype->lock_class, 0, sizeof(ktype->lock_class));
1215
1216 ret = -EEXIST;
1217 down_write(&key_types_sem);
1218
1219 /* disallow key types with the same name */
1220 list_for_each_entry(p, &key_types_list, link) {
1221 if (strcmp(p->name, ktype->name) == 0)
1222 goto out;
1223 }
1224
1225 /* store the type */
1226 list_add(&ktype->link, &key_types_list);
1227
1228 pr_notice("Key type %s registered\n", ktype->name);
1229 ret = 0;
1230
1231out:
1232 up_write(&key_types_sem);
1233 return ret;
1234}
1235EXPORT_SYMBOL(register_key_type);
1236
1237/**
1238 * unregister_key_type - Unregister a type of key.
1239 * @ktype: The key type.
1240 *
1241 * Unregister a key type and mark all the extant keys of this type as dead.
1242 * Those keys of this type are then destroyed to get rid of their payloads and
1243 * they and their links will be garbage collected as soon as possible.
1244 */
1245void unregister_key_type(struct key_type *ktype)
1246{
1247 down_write(&key_types_sem);
1248 list_del_init(&ktype->link);
1249 downgrade_write(&key_types_sem);
1250 key_gc_keytype(ktype);
1251 pr_notice("Key type %s unregistered\n", ktype->name);
1252 up_read(&key_types_sem);
1253}
1254EXPORT_SYMBOL(unregister_key_type);
1255
1256/*
1257 * Initialise the key management state.
1258 */
1259void __init key_init(void)
1260{
1261 /* allocate a slab in which we can store keys */
1262 key_jar = kmem_cache_create("key_jar", sizeof(struct key),
1263 0, SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
1264
1265 /* add the special key types */
1266 list_add_tail(&key_type_keyring.link, &key_types_list);
1267 list_add_tail(&key_type_dead.link, &key_types_list);
1268 list_add_tail(&key_type_user.link, &key_types_list);
1269 list_add_tail(&key_type_logon.link, &key_types_list);
1270
1271 /* record the root user tracking */
1272 rb_link_node(&root_key_user.node,
1273 NULL,
1274 &key_user_tree.rb_node);
1275
1276 rb_insert_color(&root_key_user.node,
1277 &key_user_tree);
1278}