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1/* Basic authentication token and access key management
2 *
3 * Copyright (C) 2004-2008 Red Hat, Inc. All Rights Reserved.
4 * Written by David Howells (dhowells@redhat.com)
5 *
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public License
8 * as published by the Free Software Foundation; either version
9 * 2 of the License, or (at your option) any later version.
10 */
11
12#include <linux/module.h>
13#include <linux/init.h>
14#include <linux/poison.h>
15#include <linux/sched.h>
16#include <linux/slab.h>
17#include <linux/security.h>
18#include <linux/workqueue.h>
19#include <linux/random.h>
20#include <linux/err.h>
21#include "internal.h"
22
23struct kmem_cache *key_jar;
24struct rb_root key_serial_tree; /* tree of keys indexed by serial */
25DEFINE_SPINLOCK(key_serial_lock);
26
27struct rb_root key_user_tree; /* tree of quota records indexed by UID */
28DEFINE_SPINLOCK(key_user_lock);
29
30unsigned int key_quota_root_maxkeys = 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 *
205 * Allocate a key of the specified type with the attributes given. The key is
206 * returned in an uninstantiated state and the caller needs to instantiate the
207 * key before returning.
208 *
209 * The user's key count quota is updated to reflect the creation of the key and
210 * the user's key data quota has the default for the key type reserved. The
211 * instantiation function should amend this as necessary. If insufficient
212 * quota is available, -EDQUOT will be returned.
213 *
214 * The LSM security modules can prevent a key being created, in which case
215 * -EACCES will be returned.
216 *
217 * Returns a pointer to the new key if successful and an error code otherwise.
218 *
219 * Note that the caller needs to ensure the key type isn't uninstantiated.
220 * Internally this can be done by locking key_types_sem. Externally, this can
221 * be done by either never unregistering the key type, or making sure
222 * key_alloc() calls don't race with module unloading.
223 */
224struct key *key_alloc(struct key_type *type, const char *desc,
225 kuid_t uid, kgid_t gid, const struct cred *cred,
226 key_perm_t perm, unsigned long flags)
227{
228 struct key_user *user = NULL;
229 struct key *key;
230 size_t desclen, quotalen;
231 int ret;
232
233 key = ERR_PTR(-EINVAL);
234 if (!desc || !*desc)
235 goto error;
236
237 if (type->vet_description) {
238 ret = type->vet_description(desc);
239 if (ret < 0) {
240 key = ERR_PTR(ret);
241 goto error;
242 }
243 }
244
245 desclen = strlen(desc);
246 quotalen = desclen + 1 + type->def_datalen;
247
248 /* get hold of the key tracking for this user */
249 user = key_user_lookup(uid);
250 if (!user)
251 goto no_memory_1;
252
253 /* check that the user's quota permits allocation of another key and
254 * its description */
255 if (!(flags & KEY_ALLOC_NOT_IN_QUOTA)) {
256 unsigned maxkeys = uid_eq(uid, GLOBAL_ROOT_UID) ?
257 key_quota_root_maxkeys : key_quota_maxkeys;
258 unsigned maxbytes = uid_eq(uid, GLOBAL_ROOT_UID) ?
259 key_quota_root_maxbytes : key_quota_maxbytes;
260
261 spin_lock(&user->lock);
262 if (!(flags & KEY_ALLOC_QUOTA_OVERRUN)) {
263 if (user->qnkeys + 1 >= maxkeys ||
264 user->qnbytes + quotalen >= maxbytes ||
265 user->qnbytes + quotalen < user->qnbytes)
266 goto no_quota;
267 }
268
269 user->qnkeys++;
270 user->qnbytes += quotalen;
271 spin_unlock(&user->lock);
272 }
273
274 /* allocate and initialise the key and its description */
275 key = kmem_cache_zalloc(key_jar, GFP_KERNEL);
276 if (!key)
277 goto no_memory_2;
278
279 key->index_key.desc_len = desclen;
280 key->index_key.description = kmemdup(desc, desclen + 1, GFP_KERNEL);
281 if (!key->index_key.description)
282 goto no_memory_3;
283
284 atomic_set(&key->usage, 1);
285 init_rwsem(&key->sem);
286 lockdep_set_class(&key->sem, &type->lock_class);
287 key->index_key.type = type;
288 key->user = user;
289 key->quotalen = quotalen;
290 key->datalen = type->def_datalen;
291 key->uid = uid;
292 key->gid = gid;
293 key->perm = perm;
294
295 if (!(flags & KEY_ALLOC_NOT_IN_QUOTA))
296 key->flags |= 1 << KEY_FLAG_IN_QUOTA;
297 if (flags & KEY_ALLOC_TRUSTED)
298 key->flags |= 1 << KEY_FLAG_TRUSTED;
299 if (flags & KEY_ALLOC_BUILT_IN)
300 key->flags |= 1 << KEY_FLAG_BUILTIN;
301
302#ifdef KEY_DEBUGGING
303 key->magic = KEY_DEBUG_MAGIC;
304#endif
305
306 /* let the security module know about the key */
307 ret = security_key_alloc(key, cred, flags);
308 if (ret < 0)
309 goto security_error;
310
311 /* publish the key by giving it a serial number */
312 atomic_inc(&user->nkeys);
313 key_alloc_serial(key);
314
315error:
316 return key;
317
318security_error:
319 kfree(key->description);
320 kmem_cache_free(key_jar, key);
321 if (!(flags & KEY_ALLOC_NOT_IN_QUOTA)) {
322 spin_lock(&user->lock);
323 user->qnkeys--;
324 user->qnbytes -= quotalen;
325 spin_unlock(&user->lock);
326 }
327 key_user_put(user);
328 key = ERR_PTR(ret);
329 goto error;
330
331no_memory_3:
332 kmem_cache_free(key_jar, key);
333no_memory_2:
334 if (!(flags & KEY_ALLOC_NOT_IN_QUOTA)) {
335 spin_lock(&user->lock);
336 user->qnkeys--;
337 user->qnbytes -= quotalen;
338 spin_unlock(&user->lock);
339 }
340 key_user_put(user);
341no_memory_1:
342 key = ERR_PTR(-ENOMEM);
343 goto error;
344
345no_quota:
346 spin_unlock(&user->lock);
347 key_user_put(user);
348 key = ERR_PTR(-EDQUOT);
349 goto error;
350}
351EXPORT_SYMBOL(key_alloc);
352
353/**
354 * key_payload_reserve - Adjust data quota reservation for the key's payload
355 * @key: The key to make the reservation for.
356 * @datalen: The amount of data payload the caller now wants.
357 *
358 * Adjust the amount of the owning user's key data quota that a key reserves.
359 * If the amount is increased, then -EDQUOT may be returned if there isn't
360 * enough free quota available.
361 *
362 * If successful, 0 is returned.
363 */
364int key_payload_reserve(struct key *key, size_t datalen)
365{
366 int delta = (int)datalen - key->datalen;
367 int ret = 0;
368
369 key_check(key);
370
371 /* contemplate the quota adjustment */
372 if (delta != 0 && test_bit(KEY_FLAG_IN_QUOTA, &key->flags)) {
373 unsigned maxbytes = uid_eq(key->user->uid, GLOBAL_ROOT_UID) ?
374 key_quota_root_maxbytes : key_quota_maxbytes;
375
376 spin_lock(&key->user->lock);
377
378 if (delta > 0 &&
379 (key->user->qnbytes + delta >= maxbytes ||
380 key->user->qnbytes + delta < key->user->qnbytes)) {
381 ret = -EDQUOT;
382 }
383 else {
384 key->user->qnbytes += delta;
385 key->quotalen += delta;
386 }
387 spin_unlock(&key->user->lock);
388 }
389
390 /* change the recorded data length if that didn't generate an error */
391 if (ret == 0)
392 key->datalen = datalen;
393
394 return ret;
395}
396EXPORT_SYMBOL(key_payload_reserve);
397
398/*
399 * Instantiate a key and link it into the target keyring atomically. Must be
400 * called with the target keyring's semaphore writelocked. The target key's
401 * semaphore need not be locked as instantiation is serialised by
402 * key_construction_mutex.
403 */
404static int __key_instantiate_and_link(struct key *key,
405 struct key_preparsed_payload *prep,
406 struct key *keyring,
407 struct key *authkey,
408 struct assoc_array_edit **_edit)
409{
410 int ret, awaken;
411
412 key_check(key);
413 key_check(keyring);
414
415 awaken = 0;
416 ret = -EBUSY;
417
418 mutex_lock(&key_construction_mutex);
419
420 /* can't instantiate twice */
421 if (!test_bit(KEY_FLAG_INSTANTIATED, &key->flags)) {
422 /* instantiate the key */
423 ret = key->type->instantiate(key, prep);
424
425 if (ret == 0) {
426 /* mark the key as being instantiated */
427 atomic_inc(&key->user->nikeys);
428 set_bit(KEY_FLAG_INSTANTIATED, &key->flags);
429
430 if (test_and_clear_bit(KEY_FLAG_USER_CONSTRUCT, &key->flags))
431 awaken = 1;
432
433 /* and link it into the destination keyring */
434 if (keyring) {
435 if (test_bit(KEY_FLAG_KEEP, &keyring->flags))
436 set_bit(KEY_FLAG_KEEP, &key->flags);
437
438 __key_link(key, _edit);
439 }
440
441 /* disable the authorisation key */
442 if (authkey)
443 key_revoke(authkey);
444
445 if (prep->expiry != TIME_T_MAX) {
446 key->expiry = prep->expiry;
447 key_schedule_gc(prep->expiry + key_gc_delay);
448 }
449 }
450 }
451
452 mutex_unlock(&key_construction_mutex);
453
454 /* wake up anyone waiting for a key to be constructed */
455 if (awaken)
456 wake_up_bit(&key->flags, KEY_FLAG_USER_CONSTRUCT);
457
458 return ret;
459}
460
461/**
462 * key_instantiate_and_link - Instantiate a key and link it into the keyring.
463 * @key: The key to instantiate.
464 * @data: The data to use to instantiate the keyring.
465 * @datalen: The length of @data.
466 * @keyring: Keyring to create a link in on success (or NULL).
467 * @authkey: The authorisation token permitting instantiation.
468 *
469 * Instantiate a key that's in the uninstantiated state using the provided data
470 * and, if successful, link it in to the destination keyring if one is
471 * supplied.
472 *
473 * If successful, 0 is returned, the authorisation token is revoked and anyone
474 * waiting for the key is woken up. If the key was already instantiated,
475 * -EBUSY will be returned.
476 */
477int key_instantiate_and_link(struct key *key,
478 const void *data,
479 size_t datalen,
480 struct key *keyring,
481 struct key *authkey)
482{
483 struct key_preparsed_payload prep;
484 struct assoc_array_edit *edit;
485 int ret;
486
487 memset(&prep, 0, sizeof(prep));
488 prep.data = data;
489 prep.datalen = datalen;
490 prep.quotalen = key->type->def_datalen;
491 prep.expiry = TIME_T_MAX;
492 if (key->type->preparse) {
493 ret = key->type->preparse(&prep);
494 if (ret < 0)
495 goto error;
496 }
497
498 if (keyring) {
499 ret = __key_link_begin(keyring, &key->index_key, &edit);
500 if (ret < 0)
501 goto error;
502 }
503
504 ret = __key_instantiate_and_link(key, &prep, keyring, authkey, &edit);
505
506 if (keyring)
507 __key_link_end(keyring, &key->index_key, edit);
508
509error:
510 if (key->type->preparse)
511 key->type->free_preparse(&prep);
512 return ret;
513}
514
515EXPORT_SYMBOL(key_instantiate_and_link);
516
517/**
518 * key_reject_and_link - Negatively instantiate a key and link it into the keyring.
519 * @key: The key to instantiate.
520 * @timeout: The timeout on the negative key.
521 * @error: The error to return when the key is hit.
522 * @keyring: Keyring to create a link in on success (or NULL).
523 * @authkey: The authorisation token permitting instantiation.
524 *
525 * Negatively instantiate a key that's in the uninstantiated state and, if
526 * successful, set its timeout and stored error and link it in to the
527 * destination keyring if one is supplied. The key and any links to the key
528 * will be automatically garbage collected after the timeout expires.
529 *
530 * Negative keys are used to rate limit repeated request_key() calls by causing
531 * them to return the stored error code (typically ENOKEY) until the negative
532 * key expires.
533 *
534 * If successful, 0 is returned, the authorisation token is revoked and anyone
535 * waiting for the key is woken up. If the key was already instantiated,
536 * -EBUSY will be returned.
537 */
538int key_reject_and_link(struct key *key,
539 unsigned timeout,
540 unsigned error,
541 struct key *keyring,
542 struct key *authkey)
543{
544 struct assoc_array_edit *edit;
545 struct timespec now;
546 int ret, awaken, link_ret = 0;
547
548 key_check(key);
549 key_check(keyring);
550
551 awaken = 0;
552 ret = -EBUSY;
553
554 if (keyring)
555 link_ret = __key_link_begin(keyring, &key->index_key, &edit);
556
557 mutex_lock(&key_construction_mutex);
558
559 /* can't instantiate twice */
560 if (!test_bit(KEY_FLAG_INSTANTIATED, &key->flags)) {
561 /* mark the key as being negatively instantiated */
562 atomic_inc(&key->user->nikeys);
563 key->reject_error = -error;
564 smp_wmb();
565 set_bit(KEY_FLAG_NEGATIVE, &key->flags);
566 set_bit(KEY_FLAG_INSTANTIATED, &key->flags);
567 now = current_kernel_time();
568 key->expiry = now.tv_sec + timeout;
569 key_schedule_gc(key->expiry + key_gc_delay);
570
571 if (test_and_clear_bit(KEY_FLAG_USER_CONSTRUCT, &key->flags))
572 awaken = 1;
573
574 ret = 0;
575
576 /* and link it into the destination keyring */
577 if (keyring && link_ret == 0)
578 __key_link(key, &edit);
579
580 /* disable the authorisation key */
581 if (authkey)
582 key_revoke(authkey);
583 }
584
585 mutex_unlock(&key_construction_mutex);
586
587 if (keyring)
588 __key_link_end(keyring, &key->index_key, edit);
589
590 /* wake up anyone waiting for a key to be constructed */
591 if (awaken)
592 wake_up_bit(&key->flags, KEY_FLAG_USER_CONSTRUCT);
593
594 return ret == 0 ? link_ret : ret;
595}
596EXPORT_SYMBOL(key_reject_and_link);
597
598/**
599 * key_put - Discard a reference to a key.
600 * @key: The key to discard a reference from.
601 *
602 * Discard a reference to a key, and when all the references are gone, we
603 * schedule the cleanup task to come and pull it out of the tree in process
604 * context at some later time.
605 */
606void key_put(struct key *key)
607{
608 if (key) {
609 key_check(key);
610
611 if (atomic_dec_and_test(&key->usage))
612 schedule_work(&key_gc_work);
613 }
614}
615EXPORT_SYMBOL(key_put);
616
617/*
618 * Find a key by its serial number.
619 */
620struct key *key_lookup(key_serial_t id)
621{
622 struct rb_node *n;
623 struct key *key;
624
625 spin_lock(&key_serial_lock);
626
627 /* search the tree for the specified key */
628 n = key_serial_tree.rb_node;
629 while (n) {
630 key = rb_entry(n, struct key, serial_node);
631
632 if (id < key->serial)
633 n = n->rb_left;
634 else if (id > key->serial)
635 n = n->rb_right;
636 else
637 goto found;
638 }
639
640not_found:
641 key = ERR_PTR(-ENOKEY);
642 goto error;
643
644found:
645 /* pretend it doesn't exist if it is awaiting deletion */
646 if (atomic_read(&key->usage) == 0)
647 goto not_found;
648
649 /* this races with key_put(), but that doesn't matter since key_put()
650 * doesn't actually change the key
651 */
652 __key_get(key);
653
654error:
655 spin_unlock(&key_serial_lock);
656 return key;
657}
658
659/*
660 * Find and lock the specified key type against removal.
661 *
662 * We return with the sem read-locked if successful. If the type wasn't
663 * available -ENOKEY is returned instead.
664 */
665struct key_type *key_type_lookup(const char *type)
666{
667 struct key_type *ktype;
668
669 down_read(&key_types_sem);
670
671 /* look up the key type to see if it's one of the registered kernel
672 * types */
673 list_for_each_entry(ktype, &key_types_list, link) {
674 if (strcmp(ktype->name, type) == 0)
675 goto found_kernel_type;
676 }
677
678 up_read(&key_types_sem);
679 ktype = ERR_PTR(-ENOKEY);
680
681found_kernel_type:
682 return ktype;
683}
684
685void key_set_timeout(struct key *key, unsigned timeout)
686{
687 struct timespec now;
688 time_t expiry = 0;
689
690 /* make the changes with the locks held to prevent races */
691 down_write(&key->sem);
692
693 if (timeout > 0) {
694 now = current_kernel_time();
695 expiry = now.tv_sec + timeout;
696 }
697
698 key->expiry = expiry;
699 key_schedule_gc(key->expiry + key_gc_delay);
700
701 up_write(&key->sem);
702}
703EXPORT_SYMBOL_GPL(key_set_timeout);
704
705/*
706 * Unlock a key type locked by key_type_lookup().
707 */
708void key_type_put(struct key_type *ktype)
709{
710 up_read(&key_types_sem);
711}
712
713/*
714 * Attempt to update an existing key.
715 *
716 * The key is given to us with an incremented refcount that we need to discard
717 * if we get an error.
718 */
719static inline key_ref_t __key_update(key_ref_t key_ref,
720 struct key_preparsed_payload *prep)
721{
722 struct key *key = key_ref_to_ptr(key_ref);
723 int ret;
724
725 /* need write permission on the key to update it */
726 ret = key_permission(key_ref, KEY_NEED_WRITE);
727 if (ret < 0)
728 goto error;
729
730 ret = -EEXIST;
731 if (!key->type->update)
732 goto error;
733
734 down_write(&key->sem);
735
736 ret = key->type->update(key, prep);
737 if (ret == 0)
738 /* updating a negative key instantiates it */
739 clear_bit(KEY_FLAG_NEGATIVE, &key->flags);
740
741 up_write(&key->sem);
742
743 if (ret < 0)
744 goto error;
745out:
746 return key_ref;
747
748error:
749 key_put(key);
750 key_ref = ERR_PTR(ret);
751 goto out;
752}
753
754/**
755 * key_create_or_update - Update or create and instantiate a key.
756 * @keyring_ref: A pointer to the destination keyring with possession flag.
757 * @type: The type of key.
758 * @description: The searchable description for the key.
759 * @payload: The data to use to instantiate or update the key.
760 * @plen: The length of @payload.
761 * @perm: The permissions mask for a new key.
762 * @flags: The quota flags for a new key.
763 *
764 * Search the destination keyring for a key of the same description and if one
765 * is found, update it, otherwise create and instantiate a new one and create a
766 * link to it from that keyring.
767 *
768 * If perm is KEY_PERM_UNDEF then an appropriate key permissions mask will be
769 * concocted.
770 *
771 * Returns a pointer to the new key if successful, -ENODEV if the key type
772 * wasn't available, -ENOTDIR if the keyring wasn't a keyring, -EACCES if the
773 * caller isn't permitted to modify the keyring or the LSM did not permit
774 * creation of the key.
775 *
776 * On success, the possession flag from the keyring ref will be tacked on to
777 * the key ref before it is returned.
778 */
779key_ref_t key_create_or_update(key_ref_t keyring_ref,
780 const char *type,
781 const char *description,
782 const void *payload,
783 size_t plen,
784 key_perm_t perm,
785 unsigned long flags)
786{
787 struct keyring_index_key index_key = {
788 .description = description,
789 };
790 struct key_preparsed_payload prep;
791 struct assoc_array_edit *edit;
792 const struct cred *cred = current_cred();
793 struct key *keyring, *key = NULL;
794 key_ref_t key_ref;
795 int ret;
796
797 /* look up the key type to see if it's one of the registered kernel
798 * types */
799 index_key.type = key_type_lookup(type);
800 if (IS_ERR(index_key.type)) {
801 key_ref = ERR_PTR(-ENODEV);
802 goto error;
803 }
804
805 key_ref = ERR_PTR(-EINVAL);
806 if (!index_key.type->instantiate ||
807 (!index_key.description && !index_key.type->preparse))
808 goto error_put_type;
809
810 keyring = key_ref_to_ptr(keyring_ref);
811
812 key_check(keyring);
813
814 key_ref = ERR_PTR(-ENOTDIR);
815 if (keyring->type != &key_type_keyring)
816 goto error_put_type;
817
818 memset(&prep, 0, sizeof(prep));
819 prep.data = payload;
820 prep.datalen = plen;
821 prep.quotalen = index_key.type->def_datalen;
822 prep.trusted = flags & KEY_ALLOC_TRUSTED;
823 prep.expiry = TIME_T_MAX;
824 if (index_key.type->preparse) {
825 ret = index_key.type->preparse(&prep);
826 if (ret < 0) {
827 key_ref = ERR_PTR(ret);
828 goto error_free_prep;
829 }
830 if (!index_key.description)
831 index_key.description = prep.description;
832 key_ref = ERR_PTR(-EINVAL);
833 if (!index_key.description)
834 goto error_free_prep;
835 }
836 index_key.desc_len = strlen(index_key.description);
837
838 key_ref = ERR_PTR(-EPERM);
839 if (!prep.trusted && test_bit(KEY_FLAG_TRUSTED_ONLY, &keyring->flags))
840 goto error_free_prep;
841 flags |= prep.trusted ? KEY_ALLOC_TRUSTED : 0;
842
843 ret = __key_link_begin(keyring, &index_key, &edit);
844 if (ret < 0) {
845 key_ref = ERR_PTR(ret);
846 goto error_free_prep;
847 }
848
849 /* if we're going to allocate a new key, we're going to have
850 * to modify the keyring */
851 ret = key_permission(keyring_ref, KEY_NEED_WRITE);
852 if (ret < 0) {
853 key_ref = ERR_PTR(ret);
854 goto error_link_end;
855 }
856
857 /* if it's possible to update this type of key, search for an existing
858 * key of the same type and description in the destination keyring and
859 * update that instead if possible
860 */
861 if (index_key.type->update) {
862 key_ref = find_key_to_update(keyring_ref, &index_key);
863 if (key_ref)
864 goto found_matching_key;
865 }
866
867 /* if the client doesn't provide, decide on the permissions we want */
868 if (perm == KEY_PERM_UNDEF) {
869 perm = KEY_POS_VIEW | KEY_POS_SEARCH | KEY_POS_LINK | KEY_POS_SETATTR;
870 perm |= KEY_USR_VIEW;
871
872 if (index_key.type->read)
873 perm |= KEY_POS_READ;
874
875 if (index_key.type == &key_type_keyring ||
876 index_key.type->update)
877 perm |= KEY_POS_WRITE;
878 }
879
880 /* allocate a new key */
881 key = key_alloc(index_key.type, index_key.description,
882 cred->fsuid, cred->fsgid, cred, perm, flags);
883 if (IS_ERR(key)) {
884 key_ref = ERR_CAST(key);
885 goto error_link_end;
886 }
887
888 /* instantiate it and link it into the target keyring */
889 ret = __key_instantiate_and_link(key, &prep, keyring, NULL, &edit);
890 if (ret < 0) {
891 key_put(key);
892 key_ref = ERR_PTR(ret);
893 goto error_link_end;
894 }
895
896 key_ref = make_key_ref(key, is_key_possessed(keyring_ref));
897
898error_link_end:
899 __key_link_end(keyring, &index_key, edit);
900error_free_prep:
901 if (index_key.type->preparse)
902 index_key.type->free_preparse(&prep);
903error_put_type:
904 key_type_put(index_key.type);
905error:
906 return key_ref;
907
908 found_matching_key:
909 /* we found a matching key, so we're going to try to update it
910 * - we can drop the locks first as we have the key pinned
911 */
912 __key_link_end(keyring, &index_key, edit);
913
914 key_ref = __key_update(key_ref, &prep);
915 goto error_free_prep;
916}
917EXPORT_SYMBOL(key_create_or_update);
918
919/**
920 * key_update - Update a key's contents.
921 * @key_ref: The pointer (plus possession flag) to the key.
922 * @payload: The data to be used to update the key.
923 * @plen: The length of @payload.
924 *
925 * Attempt to update the contents of a key with the given payload data. The
926 * caller must be granted Write permission on the key. Negative keys can be
927 * instantiated by this method.
928 *
929 * Returns 0 on success, -EACCES if not permitted and -EOPNOTSUPP if the key
930 * type does not support updating. The key type may return other errors.
931 */
932int key_update(key_ref_t key_ref, const void *payload, size_t plen)
933{
934 struct key_preparsed_payload prep;
935 struct key *key = key_ref_to_ptr(key_ref);
936 int ret;
937
938 key_check(key);
939
940 /* the key must be writable */
941 ret = key_permission(key_ref, KEY_NEED_WRITE);
942 if (ret < 0)
943 goto error;
944
945 /* attempt to update it if supported */
946 ret = -EOPNOTSUPP;
947 if (!key->type->update)
948 goto error;
949
950 memset(&prep, 0, sizeof(prep));
951 prep.data = payload;
952 prep.datalen = plen;
953 prep.quotalen = key->type->def_datalen;
954 prep.expiry = TIME_T_MAX;
955 if (key->type->preparse) {
956 ret = key->type->preparse(&prep);
957 if (ret < 0)
958 goto error;
959 }
960
961 down_write(&key->sem);
962
963 ret = key->type->update(key, &prep);
964 if (ret == 0)
965 /* updating a negative key instantiates it */
966 clear_bit(KEY_FLAG_NEGATIVE, &key->flags);
967
968 up_write(&key->sem);
969
970error:
971 if (key->type->preparse)
972 key->type->free_preparse(&prep);
973 return ret;
974}
975EXPORT_SYMBOL(key_update);
976
977/**
978 * key_revoke - Revoke a key.
979 * @key: The key to be revoked.
980 *
981 * Mark a key as being revoked and ask the type to free up its resources. The
982 * revocation timeout is set and the key and all its links will be
983 * automatically garbage collected after key_gc_delay amount of time if they
984 * are not manually dealt with first.
985 */
986void key_revoke(struct key *key)
987{
988 struct timespec now;
989 time_t time;
990
991 key_check(key);
992
993 /* make sure no one's trying to change or use the key when we mark it
994 * - we tell lockdep that we might nest because we might be revoking an
995 * authorisation key whilst holding the sem on a key we've just
996 * instantiated
997 */
998 down_write_nested(&key->sem, 1);
999 if (!test_and_set_bit(KEY_FLAG_REVOKED, &key->flags) &&
1000 key->type->revoke)
1001 key->type->revoke(key);
1002
1003 /* set the death time to no more than the expiry time */
1004 now = current_kernel_time();
1005 time = now.tv_sec;
1006 if (key->revoked_at == 0 || key->revoked_at > time) {
1007 key->revoked_at = time;
1008 key_schedule_gc(key->revoked_at + key_gc_delay);
1009 }
1010
1011 up_write(&key->sem);
1012}
1013EXPORT_SYMBOL(key_revoke);
1014
1015/**
1016 * key_invalidate - Invalidate a key.
1017 * @key: The key to be invalidated.
1018 *
1019 * Mark a key as being invalidated and have it cleaned up immediately. The key
1020 * is ignored by all searches and other operations from this point.
1021 */
1022void key_invalidate(struct key *key)
1023{
1024 kenter("%d", key_serial(key));
1025
1026 key_check(key);
1027
1028 if (!test_bit(KEY_FLAG_INVALIDATED, &key->flags)) {
1029 down_write_nested(&key->sem, 1);
1030 if (!test_and_set_bit(KEY_FLAG_INVALIDATED, &key->flags))
1031 key_schedule_gc_links();
1032 up_write(&key->sem);
1033 }
1034}
1035EXPORT_SYMBOL(key_invalidate);
1036
1037/**
1038 * generic_key_instantiate - Simple instantiation of a key from preparsed data
1039 * @key: The key to be instantiated
1040 * @prep: The preparsed data to load.
1041 *
1042 * Instantiate a key from preparsed data. We assume we can just copy the data
1043 * in directly and clear the old pointers.
1044 *
1045 * This can be pointed to directly by the key type instantiate op pointer.
1046 */
1047int generic_key_instantiate(struct key *key, struct key_preparsed_payload *prep)
1048{
1049 int ret;
1050
1051 pr_devel("==>%s()\n", __func__);
1052
1053 ret = key_payload_reserve(key, prep->quotalen);
1054 if (ret == 0) {
1055 rcu_assign_keypointer(key, prep->payload.data[0]);
1056 key->payload.data[1] = prep->payload.data[1];
1057 key->payload.data[2] = prep->payload.data[2];
1058 key->payload.data[3] = prep->payload.data[3];
1059 prep->payload.data[0] = NULL;
1060 prep->payload.data[1] = NULL;
1061 prep->payload.data[2] = NULL;
1062 prep->payload.data[3] = NULL;
1063 }
1064 pr_devel("<==%s() = %d\n", __func__, ret);
1065 return ret;
1066}
1067EXPORT_SYMBOL(generic_key_instantiate);
1068
1069/**
1070 * register_key_type - Register a type of key.
1071 * @ktype: The new key type.
1072 *
1073 * Register a new key type.
1074 *
1075 * Returns 0 on success or -EEXIST if a type of this name already exists.
1076 */
1077int register_key_type(struct key_type *ktype)
1078{
1079 struct key_type *p;
1080 int ret;
1081
1082 memset(&ktype->lock_class, 0, sizeof(ktype->lock_class));
1083
1084 ret = -EEXIST;
1085 down_write(&key_types_sem);
1086
1087 /* disallow key types with the same name */
1088 list_for_each_entry(p, &key_types_list, link) {
1089 if (strcmp(p->name, ktype->name) == 0)
1090 goto out;
1091 }
1092
1093 /* store the type */
1094 list_add(&ktype->link, &key_types_list);
1095
1096 pr_notice("Key type %s registered\n", ktype->name);
1097 ret = 0;
1098
1099out:
1100 up_write(&key_types_sem);
1101 return ret;
1102}
1103EXPORT_SYMBOL(register_key_type);
1104
1105/**
1106 * unregister_key_type - Unregister a type of key.
1107 * @ktype: The key type.
1108 *
1109 * Unregister a key type and mark all the extant keys of this type as dead.
1110 * Those keys of this type are then destroyed to get rid of their payloads and
1111 * they and their links will be garbage collected as soon as possible.
1112 */
1113void unregister_key_type(struct key_type *ktype)
1114{
1115 down_write(&key_types_sem);
1116 list_del_init(&ktype->link);
1117 downgrade_write(&key_types_sem);
1118 key_gc_keytype(ktype);
1119 pr_notice("Key type %s unregistered\n", ktype->name);
1120 up_read(&key_types_sem);
1121}
1122EXPORT_SYMBOL(unregister_key_type);
1123
1124/*
1125 * Initialise the key management state.
1126 */
1127void __init key_init(void)
1128{
1129 /* allocate a slab in which we can store keys */
1130 key_jar = kmem_cache_create("key_jar", sizeof(struct key),
1131 0, SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
1132
1133 /* add the special key types */
1134 list_add_tail(&key_type_keyring.link, &key_types_list);
1135 list_add_tail(&key_type_dead.link, &key_types_list);
1136 list_add_tail(&key_type_user.link, &key_types_list);
1137 list_add_tail(&key_type_logon.link, &key_types_list);
1138
1139 /* record the root user tracking */
1140 rb_link_node(&root_key_user.node,
1141 NULL,
1142 &key_user_tree.rb_node);
1143
1144 rb_insert_color(&root_key_user.node,
1145 &key_user_tree);
1146}
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->expiry = TIME64_MAX;
298 key->restrict_link = restrict_link;
299 key->last_used_at = ktime_get_real_seconds();
300
301 if (!(flags & KEY_ALLOC_NOT_IN_QUOTA))
302 key->flags |= 1 << KEY_FLAG_IN_QUOTA;
303 if (flags & KEY_ALLOC_BUILT_IN)
304 key->flags |= 1 << KEY_FLAG_BUILTIN;
305 if (flags & KEY_ALLOC_UID_KEYRING)
306 key->flags |= 1 << KEY_FLAG_UID_KEYRING;
307 if (flags & KEY_ALLOC_SET_KEEP)
308 key->flags |= 1 << KEY_FLAG_KEEP;
309
310#ifdef KEY_DEBUGGING
311 key->magic = KEY_DEBUG_MAGIC;
312#endif
313
314 /* let the security module know about the key */
315 ret = security_key_alloc(key, cred, flags);
316 if (ret < 0)
317 goto security_error;
318
319 /* publish the key by giving it a serial number */
320 refcount_inc(&key->domain_tag->usage);
321 atomic_inc(&user->nkeys);
322 key_alloc_serial(key);
323
324error:
325 return key;
326
327security_error:
328 kfree(key->description);
329 kmem_cache_free(key_jar, key);
330 if (!(flags & KEY_ALLOC_NOT_IN_QUOTA)) {
331 spin_lock(&user->lock);
332 user->qnkeys--;
333 user->qnbytes -= quotalen;
334 spin_unlock(&user->lock);
335 }
336 key_user_put(user);
337 key = ERR_PTR(ret);
338 goto error;
339
340no_memory_3:
341 kmem_cache_free(key_jar, key);
342no_memory_2:
343 if (!(flags & KEY_ALLOC_NOT_IN_QUOTA)) {
344 spin_lock(&user->lock);
345 user->qnkeys--;
346 user->qnbytes -= quotalen;
347 spin_unlock(&user->lock);
348 }
349 key_user_put(user);
350no_memory_1:
351 key = ERR_PTR(-ENOMEM);
352 goto error;
353
354no_quota:
355 spin_unlock(&user->lock);
356 key_user_put(user);
357 key = ERR_PTR(-EDQUOT);
358 goto error;
359}
360EXPORT_SYMBOL(key_alloc);
361
362/**
363 * key_payload_reserve - Adjust data quota reservation for the key's payload
364 * @key: The key to make the reservation for.
365 * @datalen: The amount of data payload the caller now wants.
366 *
367 * Adjust the amount of the owning user's key data quota that a key reserves.
368 * If the amount is increased, then -EDQUOT may be returned if there isn't
369 * enough free quota available.
370 *
371 * If successful, 0 is returned.
372 */
373int key_payload_reserve(struct key *key, size_t datalen)
374{
375 int delta = (int)datalen - key->datalen;
376 int ret = 0;
377
378 key_check(key);
379
380 /* contemplate the quota adjustment */
381 if (delta != 0 && test_bit(KEY_FLAG_IN_QUOTA, &key->flags)) {
382 unsigned maxbytes = uid_eq(key->user->uid, GLOBAL_ROOT_UID) ?
383 key_quota_root_maxbytes : key_quota_maxbytes;
384
385 spin_lock(&key->user->lock);
386
387 if (delta > 0 &&
388 (key->user->qnbytes + delta > maxbytes ||
389 key->user->qnbytes + delta < key->user->qnbytes)) {
390 ret = -EDQUOT;
391 }
392 else {
393 key->user->qnbytes += delta;
394 key->quotalen += delta;
395 }
396 spin_unlock(&key->user->lock);
397 }
398
399 /* change the recorded data length if that didn't generate an error */
400 if (ret == 0)
401 key->datalen = datalen;
402
403 return ret;
404}
405EXPORT_SYMBOL(key_payload_reserve);
406
407/*
408 * Change the key state to being instantiated.
409 */
410static void mark_key_instantiated(struct key *key, int reject_error)
411{
412 /* Commit the payload before setting the state; barrier versus
413 * key_read_state().
414 */
415 smp_store_release(&key->state,
416 (reject_error < 0) ? reject_error : KEY_IS_POSITIVE);
417}
418
419/*
420 * Instantiate a key and link it into the target keyring atomically. Must be
421 * called with the target keyring's semaphore writelocked. The target key's
422 * semaphore need not be locked as instantiation is serialised by
423 * key_construction_mutex.
424 */
425static int __key_instantiate_and_link(struct key *key,
426 struct key_preparsed_payload *prep,
427 struct key *keyring,
428 struct key *authkey,
429 struct assoc_array_edit **_edit)
430{
431 int ret, awaken;
432
433 key_check(key);
434 key_check(keyring);
435
436 awaken = 0;
437 ret = -EBUSY;
438
439 mutex_lock(&key_construction_mutex);
440
441 /* can't instantiate twice */
442 if (key->state == KEY_IS_UNINSTANTIATED) {
443 /* instantiate the key */
444 ret = key->type->instantiate(key, prep);
445
446 if (ret == 0) {
447 /* mark the key as being instantiated */
448 atomic_inc(&key->user->nikeys);
449 mark_key_instantiated(key, 0);
450 notify_key(key, NOTIFY_KEY_INSTANTIATED, 0);
451
452 if (test_and_clear_bit(KEY_FLAG_USER_CONSTRUCT, &key->flags))
453 awaken = 1;
454
455 /* and link it into the destination keyring */
456 if (keyring) {
457 if (test_bit(KEY_FLAG_KEEP, &keyring->flags))
458 set_bit(KEY_FLAG_KEEP, &key->flags);
459
460 __key_link(keyring, key, _edit);
461 }
462
463 /* disable the authorisation key */
464 if (authkey)
465 key_invalidate(authkey);
466
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 ima_post_key_create_or_update(keyring, key, payload, plen,
934 flags, 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 ima_post_key_create_or_update(keyring, key,
968 payload, plen,
969 flags, false);
970
971 goto error_free_prep;
972}
973
974/**
975 * key_create_or_update - Update or create and instantiate a key.
976 * @keyring_ref: A pointer to the destination keyring with possession flag.
977 * @type: The type of key.
978 * @description: The searchable description for the key.
979 * @payload: The data to use to instantiate or update the key.
980 * @plen: The length of @payload.
981 * @perm: The permissions mask for a new key.
982 * @flags: The quota flags for a new key.
983 *
984 * Search the destination keyring for a key of the same description and if one
985 * is found, update it, otherwise create and instantiate a new one and create a
986 * link to it from that keyring.
987 *
988 * If perm is KEY_PERM_UNDEF then an appropriate key permissions mask will be
989 * concocted.
990 *
991 * Returns a pointer to the new key if successful, -ENODEV if the key type
992 * wasn't available, -ENOTDIR if the keyring wasn't a keyring, -EACCES if the
993 * caller isn't permitted to modify the keyring or the LSM did not permit
994 * creation of the key.
995 *
996 * On success, the possession flag from the keyring ref will be tacked on to
997 * the key ref before it is returned.
998 */
999key_ref_t key_create_or_update(key_ref_t keyring_ref,
1000 const char *type,
1001 const char *description,
1002 const void *payload,
1003 size_t plen,
1004 key_perm_t perm,
1005 unsigned long flags)
1006{
1007 return __key_create_or_update(keyring_ref, type, description, payload,
1008 plen, perm, flags, true);
1009}
1010EXPORT_SYMBOL(key_create_or_update);
1011
1012/**
1013 * key_create - Create and instantiate a key.
1014 * @keyring_ref: A pointer to the destination keyring with possession flag.
1015 * @type: The type of key.
1016 * @description: The searchable description for the key.
1017 * @payload: The data to use to instantiate or update the key.
1018 * @plen: The length of @payload.
1019 * @perm: The permissions mask for a new key.
1020 * @flags: The quota flags for a new key.
1021 *
1022 * Create and instantiate a new key and link to it from the destination keyring.
1023 *
1024 * If perm is KEY_PERM_UNDEF then an appropriate key permissions mask will be
1025 * concocted.
1026 *
1027 * Returns a pointer to the new key if successful, -EEXIST if a key with the
1028 * same description already exists, -ENODEV if the key type wasn't available,
1029 * -ENOTDIR if the keyring wasn't a keyring, -EACCES if the caller isn't
1030 * permitted to modify the keyring or the LSM did not permit creation of the
1031 * key.
1032 *
1033 * On success, the possession flag from the keyring ref will be tacked on to
1034 * the key ref before it is returned.
1035 */
1036key_ref_t key_create(key_ref_t keyring_ref,
1037 const char *type,
1038 const char *description,
1039 const void *payload,
1040 size_t plen,
1041 key_perm_t perm,
1042 unsigned long flags)
1043{
1044 return __key_create_or_update(keyring_ref, type, description, payload,
1045 plen, perm, flags, false);
1046}
1047EXPORT_SYMBOL(key_create);
1048
1049/**
1050 * key_update - Update a key's contents.
1051 * @key_ref: The pointer (plus possession flag) to the key.
1052 * @payload: The data to be used to update the key.
1053 * @plen: The length of @payload.
1054 *
1055 * Attempt to update the contents of a key with the given payload data. The
1056 * caller must be granted Write permission on the key. Negative keys can be
1057 * instantiated by this method.
1058 *
1059 * Returns 0 on success, -EACCES if not permitted and -EOPNOTSUPP if the key
1060 * type does not support updating. The key type may return other errors.
1061 */
1062int key_update(key_ref_t key_ref, const void *payload, size_t plen)
1063{
1064 struct key_preparsed_payload prep;
1065 struct key *key = key_ref_to_ptr(key_ref);
1066 int ret;
1067
1068 key_check(key);
1069
1070 /* the key must be writable */
1071 ret = key_permission(key_ref, KEY_NEED_WRITE);
1072 if (ret < 0)
1073 return ret;
1074
1075 /* attempt to update it if supported */
1076 if (!key->type->update)
1077 return -EOPNOTSUPP;
1078
1079 memset(&prep, 0, sizeof(prep));
1080 prep.data = payload;
1081 prep.datalen = plen;
1082 prep.quotalen = key->type->def_datalen;
1083 prep.expiry = TIME64_MAX;
1084 if (key->type->preparse) {
1085 ret = key->type->preparse(&prep);
1086 if (ret < 0)
1087 goto error;
1088 }
1089
1090 down_write(&key->sem);
1091
1092 ret = key->type->update(key, &prep);
1093 if (ret == 0) {
1094 /* Updating a negative key positively instantiates it */
1095 mark_key_instantiated(key, 0);
1096 notify_key(key, NOTIFY_KEY_UPDATED, 0);
1097 }
1098
1099 up_write(&key->sem);
1100
1101error:
1102 if (key->type->preparse)
1103 key->type->free_preparse(&prep);
1104 return ret;
1105}
1106EXPORT_SYMBOL(key_update);
1107
1108/**
1109 * key_revoke - Revoke a key.
1110 * @key: The key to be revoked.
1111 *
1112 * Mark a key as being revoked and ask the type to free up its resources. The
1113 * revocation timeout is set and the key and all its links will be
1114 * automatically garbage collected after key_gc_delay amount of time if they
1115 * are not manually dealt with first.
1116 */
1117void key_revoke(struct key *key)
1118{
1119 time64_t time;
1120
1121 key_check(key);
1122
1123 /* make sure no one's trying to change or use the key when we mark it
1124 * - we tell lockdep that we might nest because we might be revoking an
1125 * authorisation key whilst holding the sem on a key we've just
1126 * instantiated
1127 */
1128 down_write_nested(&key->sem, 1);
1129 if (!test_and_set_bit(KEY_FLAG_REVOKED, &key->flags)) {
1130 notify_key(key, NOTIFY_KEY_REVOKED, 0);
1131 if (key->type->revoke)
1132 key->type->revoke(key);
1133
1134 /* set the death time to no more than the expiry time */
1135 time = ktime_get_real_seconds();
1136 if (key->revoked_at == 0 || key->revoked_at > time) {
1137 key->revoked_at = time;
1138 key_schedule_gc(key->revoked_at + key_gc_delay);
1139 }
1140 }
1141
1142 up_write(&key->sem);
1143}
1144EXPORT_SYMBOL(key_revoke);
1145
1146/**
1147 * key_invalidate - Invalidate a key.
1148 * @key: The key to be invalidated.
1149 *
1150 * Mark a key as being invalidated and have it cleaned up immediately. The key
1151 * is ignored by all searches and other operations from this point.
1152 */
1153void key_invalidate(struct key *key)
1154{
1155 kenter("%d", key_serial(key));
1156
1157 key_check(key);
1158
1159 if (!test_bit(KEY_FLAG_INVALIDATED, &key->flags)) {
1160 down_write_nested(&key->sem, 1);
1161 if (!test_and_set_bit(KEY_FLAG_INVALIDATED, &key->flags)) {
1162 notify_key(key, NOTIFY_KEY_INVALIDATED, 0);
1163 key_schedule_gc_links();
1164 }
1165 up_write(&key->sem);
1166 }
1167}
1168EXPORT_SYMBOL(key_invalidate);
1169
1170/**
1171 * generic_key_instantiate - Simple instantiation of a key from preparsed data
1172 * @key: The key to be instantiated
1173 * @prep: The preparsed data to load.
1174 *
1175 * Instantiate a key from preparsed data. We assume we can just copy the data
1176 * in directly and clear the old pointers.
1177 *
1178 * This can be pointed to directly by the key type instantiate op pointer.
1179 */
1180int generic_key_instantiate(struct key *key, struct key_preparsed_payload *prep)
1181{
1182 int ret;
1183
1184 pr_devel("==>%s()\n", __func__);
1185
1186 ret = key_payload_reserve(key, prep->quotalen);
1187 if (ret == 0) {
1188 rcu_assign_keypointer(key, prep->payload.data[0]);
1189 key->payload.data[1] = prep->payload.data[1];
1190 key->payload.data[2] = prep->payload.data[2];
1191 key->payload.data[3] = prep->payload.data[3];
1192 prep->payload.data[0] = NULL;
1193 prep->payload.data[1] = NULL;
1194 prep->payload.data[2] = NULL;
1195 prep->payload.data[3] = NULL;
1196 }
1197 pr_devel("<==%s() = %d\n", __func__, ret);
1198 return ret;
1199}
1200EXPORT_SYMBOL(generic_key_instantiate);
1201
1202/**
1203 * register_key_type - Register a type of key.
1204 * @ktype: The new key type.
1205 *
1206 * Register a new key type.
1207 *
1208 * Returns 0 on success or -EEXIST if a type of this name already exists.
1209 */
1210int register_key_type(struct key_type *ktype)
1211{
1212 struct key_type *p;
1213 int ret;
1214
1215 memset(&ktype->lock_class, 0, sizeof(ktype->lock_class));
1216
1217 ret = -EEXIST;
1218 down_write(&key_types_sem);
1219
1220 /* disallow key types with the same name */
1221 list_for_each_entry(p, &key_types_list, link) {
1222 if (strcmp(p->name, ktype->name) == 0)
1223 goto out;
1224 }
1225
1226 /* store the type */
1227 list_add(&ktype->link, &key_types_list);
1228
1229 pr_notice("Key type %s registered\n", ktype->name);
1230 ret = 0;
1231
1232out:
1233 up_write(&key_types_sem);
1234 return ret;
1235}
1236EXPORT_SYMBOL(register_key_type);
1237
1238/**
1239 * unregister_key_type - Unregister a type of key.
1240 * @ktype: The key type.
1241 *
1242 * Unregister a key type and mark all the extant keys of this type as dead.
1243 * Those keys of this type are then destroyed to get rid of their payloads and
1244 * they and their links will be garbage collected as soon as possible.
1245 */
1246void unregister_key_type(struct key_type *ktype)
1247{
1248 down_write(&key_types_sem);
1249 list_del_init(&ktype->link);
1250 downgrade_write(&key_types_sem);
1251 key_gc_keytype(ktype);
1252 pr_notice("Key type %s unregistered\n", ktype->name);
1253 up_read(&key_types_sem);
1254}
1255EXPORT_SYMBOL(unregister_key_type);
1256
1257/*
1258 * Initialise the key management state.
1259 */
1260void __init key_init(void)
1261{
1262 /* allocate a slab in which we can store keys */
1263 key_jar = kmem_cache_create("key_jar", sizeof(struct key),
1264 0, SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
1265
1266 /* add the special key types */
1267 list_add_tail(&key_type_keyring.link, &key_types_list);
1268 list_add_tail(&key_type_dead.link, &key_types_list);
1269 list_add_tail(&key_type_user.link, &key_types_list);
1270 list_add_tail(&key_type_logon.link, &key_types_list);
1271
1272 /* record the root user tracking */
1273 rb_link_node(&root_key_user.node,
1274 NULL,
1275 &key_user_tree.rb_node);
1276
1277 rb_insert_color(&root_key_user.node,
1278 &key_user_tree);
1279}