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1// SPDX-License-Identifier: GPL-2.0-or-later
2/* Basic authentication token and access key management
3 *
4 * Copyright (C) 2004-2008 Red Hat, Inc. All Rights Reserved.
5 * Written by David Howells (dhowells@redhat.com)
6 */
7
8#include <linux/export.h>
9#include <linux/init.h>
10#include <linux/poison.h>
11#include <linux/sched.h>
12#include <linux/slab.h>
13#include <linux/security.h>
14#include <linux/workqueue.h>
15#include <linux/random.h>
16#include <linux/ima.h>
17#include <linux/err.h>
18#include "internal.h"
19
20struct kmem_cache *key_jar;
21struct rb_root key_serial_tree; /* tree of keys indexed by serial */
22DEFINE_SPINLOCK(key_serial_lock);
23
24struct rb_root key_user_tree; /* tree of quota records indexed by UID */
25DEFINE_SPINLOCK(key_user_lock);
26
27unsigned int key_quota_root_maxkeys = 1000000; /* root's key count quota */
28unsigned int key_quota_root_maxbytes = 25000000; /* root's key space quota */
29unsigned int key_quota_maxkeys = 200; /* general key count quota */
30unsigned int key_quota_maxbytes = 20000; /* general key space quota */
31
32static LIST_HEAD(key_types_list);
33static DECLARE_RWSEM(key_types_sem);
34
35/* We serialise key instantiation and link */
36DEFINE_MUTEX(key_construction_mutex);
37
38#ifdef KEY_DEBUGGING
39void __key_check(const struct key *key)
40{
41 printk("__key_check: key %p {%08x} should be {%08x}\n",
42 key, key->magic, KEY_DEBUG_MAGIC);
43 BUG();
44}
45#endif
46
47/*
48 * Get the key quota record for a user, allocating a new record if one doesn't
49 * already exist.
50 */
51struct key_user *key_user_lookup(kuid_t uid)
52{
53 struct key_user *candidate = NULL, *user;
54 struct rb_node *parent, **p;
55
56try_again:
57 parent = NULL;
58 p = &key_user_tree.rb_node;
59 spin_lock(&key_user_lock);
60
61 /* search the tree for a user record with a matching UID */
62 while (*p) {
63 parent = *p;
64 user = rb_entry(parent, struct key_user, node);
65
66 if (uid_lt(uid, user->uid))
67 p = &(*p)->rb_left;
68 else if (uid_gt(uid, user->uid))
69 p = &(*p)->rb_right;
70 else
71 goto found;
72 }
73
74 /* if we get here, we failed to find a match in the tree */
75 if (!candidate) {
76 /* allocate a candidate user record if we don't already have
77 * one */
78 spin_unlock(&key_user_lock);
79
80 user = NULL;
81 candidate = kmalloc(sizeof(struct key_user), GFP_KERNEL);
82 if (unlikely(!candidate))
83 goto out;
84
85 /* the allocation may have scheduled, so we need to repeat the
86 * search lest someone else added the record whilst we were
87 * asleep */
88 goto try_again;
89 }
90
91 /* if we get here, then the user record still hadn't appeared on the
92 * second pass - so we use the candidate record */
93 refcount_set(&candidate->usage, 1);
94 atomic_set(&candidate->nkeys, 0);
95 atomic_set(&candidate->nikeys, 0);
96 candidate->uid = uid;
97 candidate->qnkeys = 0;
98 candidate->qnbytes = 0;
99 spin_lock_init(&candidate->lock);
100 mutex_init(&candidate->cons_lock);
101
102 rb_link_node(&candidate->node, parent, p);
103 rb_insert_color(&candidate->node, &key_user_tree);
104 spin_unlock(&key_user_lock);
105 user = candidate;
106 goto out;
107
108 /* okay - we found a user record for this UID */
109found:
110 refcount_inc(&user->usage);
111 spin_unlock(&key_user_lock);
112 kfree(candidate);
113out:
114 return user;
115}
116
117/*
118 * Dispose of a user structure
119 */
120void key_user_put(struct key_user *user)
121{
122 if (refcount_dec_and_lock(&user->usage, &key_user_lock)) {
123 rb_erase(&user->node, &key_user_tree);
124 spin_unlock(&key_user_lock);
125
126 kfree(user);
127 }
128}
129
130/*
131 * Allocate a serial number for a key. These are assigned randomly to avoid
132 * security issues through covert channel problems.
133 */
134static inline void key_alloc_serial(struct key *key)
135{
136 struct rb_node *parent, **p;
137 struct key *xkey;
138
139 /* propose a random serial number and look for a hole for it in the
140 * serial number tree */
141 do {
142 get_random_bytes(&key->serial, sizeof(key->serial));
143
144 key->serial >>= 1; /* negative numbers are not permitted */
145 } while (key->serial < 3);
146
147 spin_lock(&key_serial_lock);
148
149attempt_insertion:
150 parent = NULL;
151 p = &key_serial_tree.rb_node;
152
153 while (*p) {
154 parent = *p;
155 xkey = rb_entry(parent, struct key, serial_node);
156
157 if (key->serial < xkey->serial)
158 p = &(*p)->rb_left;
159 else if (key->serial > xkey->serial)
160 p = &(*p)->rb_right;
161 else
162 goto serial_exists;
163 }
164
165 /* we've found a suitable hole - arrange for this key to occupy it */
166 rb_link_node(&key->serial_node, parent, p);
167 rb_insert_color(&key->serial_node, &key_serial_tree);
168
169 spin_unlock(&key_serial_lock);
170 return;
171
172 /* we found a key with the proposed serial number - walk the tree from
173 * that point looking for the next unused serial number */
174serial_exists:
175 for (;;) {
176 key->serial++;
177 if (key->serial < 3) {
178 key->serial = 3;
179 goto attempt_insertion;
180 }
181
182 parent = rb_next(parent);
183 if (!parent)
184 goto attempt_insertion;
185
186 xkey = rb_entry(parent, struct key, serial_node);
187 if (key->serial < xkey->serial)
188 goto attempt_insertion;
189 }
190}
191
192/**
193 * key_alloc - Allocate a key of the specified type.
194 * @type: The type of key to allocate.
195 * @desc: The key description to allow the key to be searched out.
196 * @uid: The owner of the new key.
197 * @gid: The group ID for the new key's group permissions.
198 * @cred: The credentials specifying UID namespace.
199 * @perm: The permissions mask of the new key.
200 * @flags: Flags specifying quota properties.
201 * @restrict_link: Optional link restriction for new keyrings.
202 *
203 * Allocate a key of the specified type with the attributes given. The key is
204 * returned in an uninstantiated state and the caller needs to instantiate the
205 * key before returning.
206 *
207 * The restrict_link structure (if not NULL) will be freed when the
208 * keyring is destroyed, so it must be dynamically allocated.
209 *
210 * The user's key count quota is updated to reflect the creation of the key and
211 * the user's key data quota has the default for the key type reserved. The
212 * instantiation function should amend this as necessary. If insufficient
213 * quota is available, -EDQUOT will be returned.
214 *
215 * The LSM security modules can prevent a key being created, in which case
216 * -EACCES will be returned.
217 *
218 * Returns a pointer to the new key if successful and an error code otherwise.
219 *
220 * Note that the caller needs to ensure the key type isn't uninstantiated.
221 * Internally this can be done by locking key_types_sem. Externally, this can
222 * be done by either never unregistering the key type, or making sure
223 * key_alloc() calls don't race with module unloading.
224 */
225struct key *key_alloc(struct key_type *type, const char *desc,
226 kuid_t uid, kgid_t gid, const struct cred *cred,
227 key_perm_t perm, unsigned long flags,
228 struct key_restriction *restrict_link)
229{
230 struct key_user *user = NULL;
231 struct key *key;
232 size_t desclen, quotalen;
233 int ret;
234
235 key = ERR_PTR(-EINVAL);
236 if (!desc || !*desc)
237 goto error;
238
239 if (type->vet_description) {
240 ret = type->vet_description(desc);
241 if (ret < 0) {
242 key = ERR_PTR(ret);
243 goto error;
244 }
245 }
246
247 desclen = strlen(desc);
248 quotalen = desclen + 1 + type->def_datalen;
249
250 /* get hold of the key tracking for this user */
251 user = key_user_lookup(uid);
252 if (!user)
253 goto no_memory_1;
254
255 /* check that the user's quota permits allocation of another key and
256 * its description */
257 if (!(flags & KEY_ALLOC_NOT_IN_QUOTA)) {
258 unsigned maxkeys = uid_eq(uid, GLOBAL_ROOT_UID) ?
259 key_quota_root_maxkeys : key_quota_maxkeys;
260 unsigned maxbytes = uid_eq(uid, GLOBAL_ROOT_UID) ?
261 key_quota_root_maxbytes : key_quota_maxbytes;
262
263 spin_lock(&user->lock);
264 if (!(flags & KEY_ALLOC_QUOTA_OVERRUN)) {
265 if (user->qnkeys + 1 > maxkeys ||
266 user->qnbytes + quotalen > maxbytes ||
267 user->qnbytes + quotalen < user->qnbytes)
268 goto no_quota;
269 }
270
271 user->qnkeys++;
272 user->qnbytes += quotalen;
273 spin_unlock(&user->lock);
274 }
275
276 /* allocate and initialise the key and its description */
277 key = kmem_cache_zalloc(key_jar, GFP_KERNEL);
278 if (!key)
279 goto no_memory_2;
280
281 key->index_key.desc_len = desclen;
282 key->index_key.description = kmemdup(desc, desclen + 1, GFP_KERNEL);
283 if (!key->index_key.description)
284 goto no_memory_3;
285 key->index_key.type = type;
286 key_set_index_key(&key->index_key);
287
288 refcount_set(&key->usage, 1);
289 init_rwsem(&key->sem);
290 lockdep_set_class(&key->sem, &type->lock_class);
291 key->user = user;
292 key->quotalen = quotalen;
293 key->datalen = type->def_datalen;
294 key->uid = uid;
295 key->gid = gid;
296 key->perm = perm;
297 key->restrict_link = restrict_link;
298 key->last_used_at = ktime_get_real_seconds();
299
300 if (!(flags & KEY_ALLOC_NOT_IN_QUOTA))
301 key->flags |= 1 << KEY_FLAG_IN_QUOTA;
302 if (flags & KEY_ALLOC_BUILT_IN)
303 key->flags |= 1 << KEY_FLAG_BUILTIN;
304 if (flags & KEY_ALLOC_UID_KEYRING)
305 key->flags |= 1 << KEY_FLAG_UID_KEYRING;
306 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->expiry = prep->expiry;
468 key_schedule_gc(prep->expiry + key_gc_delay);
469 }
470 }
471 }
472
473 mutex_unlock(&key_construction_mutex);
474
475 /* wake up anyone waiting for a key to be constructed */
476 if (awaken)
477 wake_up_bit(&key->flags, KEY_FLAG_USER_CONSTRUCT);
478
479 return ret;
480}
481
482/**
483 * key_instantiate_and_link - Instantiate a key and link it into the keyring.
484 * @key: The key to instantiate.
485 * @data: The data to use to instantiate the keyring.
486 * @datalen: The length of @data.
487 * @keyring: Keyring to create a link in on success (or NULL).
488 * @authkey: The authorisation token permitting instantiation.
489 *
490 * Instantiate a key that's in the uninstantiated state using the provided data
491 * and, if successful, link it in to the destination keyring if one is
492 * supplied.
493 *
494 * If successful, 0 is returned, the authorisation token is revoked and anyone
495 * waiting for the key is woken up. If the key was already instantiated,
496 * -EBUSY will be returned.
497 */
498int key_instantiate_and_link(struct key *key,
499 const void *data,
500 size_t datalen,
501 struct key *keyring,
502 struct key *authkey)
503{
504 struct key_preparsed_payload prep;
505 struct assoc_array_edit *edit = NULL;
506 int ret;
507
508 memset(&prep, 0, sizeof(prep));
509 prep.orig_description = key->description;
510 prep.data = data;
511 prep.datalen = datalen;
512 prep.quotalen = key->type->def_datalen;
513 prep.expiry = TIME64_MAX;
514 if (key->type->preparse) {
515 ret = key->type->preparse(&prep);
516 if (ret < 0)
517 goto error;
518 }
519
520 if (keyring) {
521 ret = __key_link_lock(keyring, &key->index_key);
522 if (ret < 0)
523 goto error;
524
525 ret = __key_link_begin(keyring, &key->index_key, &edit);
526 if (ret < 0)
527 goto error_link_end;
528
529 if (keyring->restrict_link && keyring->restrict_link->check) {
530 struct key_restriction *keyres = keyring->restrict_link;
531
532 ret = keyres->check(keyring, key->type, &prep.payload,
533 keyres->key);
534 if (ret < 0)
535 goto error_link_end;
536 }
537 }
538
539 ret = __key_instantiate_and_link(key, &prep, keyring, authkey, &edit);
540
541error_link_end:
542 if (keyring)
543 __key_link_end(keyring, &key->index_key, edit);
544
545error:
546 if (key->type->preparse)
547 key->type->free_preparse(&prep);
548 return ret;
549}
550
551EXPORT_SYMBOL(key_instantiate_and_link);
552
553/**
554 * key_reject_and_link - Negatively instantiate a key and link it into the keyring.
555 * @key: The key to instantiate.
556 * @timeout: The timeout on the negative key.
557 * @error: The error to return when the key is hit.
558 * @keyring: Keyring to create a link in on success (or NULL).
559 * @authkey: The authorisation token permitting instantiation.
560 *
561 * Negatively instantiate a key that's in the uninstantiated state and, if
562 * successful, set its timeout and stored error and link it in to the
563 * destination keyring if one is supplied. The key and any links to the key
564 * will be automatically garbage collected after the timeout expires.
565 *
566 * Negative keys are used to rate limit repeated request_key() calls by causing
567 * them to return the stored error code (typically ENOKEY) until the negative
568 * key expires.
569 *
570 * If successful, 0 is returned, the authorisation token is revoked and anyone
571 * waiting for the key is woken up. If the key was already instantiated,
572 * -EBUSY will be returned.
573 */
574int key_reject_and_link(struct key *key,
575 unsigned timeout,
576 unsigned error,
577 struct key *keyring,
578 struct key *authkey)
579{
580 struct assoc_array_edit *edit = NULL;
581 int ret, awaken, link_ret = 0;
582
583 key_check(key);
584 key_check(keyring);
585
586 awaken = 0;
587 ret = -EBUSY;
588
589 if (keyring) {
590 if (keyring->restrict_link)
591 return -EPERM;
592
593 link_ret = __key_link_lock(keyring, &key->index_key);
594 if (link_ret == 0) {
595 link_ret = __key_link_begin(keyring, &key->index_key, &edit);
596 if (link_ret < 0)
597 __key_link_end(keyring, &key->index_key, edit);
598 }
599 }
600
601 mutex_lock(&key_construction_mutex);
602
603 /* can't instantiate twice */
604 if (key->state == KEY_IS_UNINSTANTIATED) {
605 /* mark the key as being negatively instantiated */
606 atomic_inc(&key->user->nikeys);
607 mark_key_instantiated(key, -error);
608 notify_key(key, NOTIFY_KEY_INSTANTIATED, -error);
609 key->expiry = ktime_get_real_seconds() + timeout;
610 key_schedule_gc(key->expiry + key_gc_delay);
611
612 if (test_and_clear_bit(KEY_FLAG_USER_CONSTRUCT, &key->flags))
613 awaken = 1;
614
615 ret = 0;
616
617 /* and link it into the destination keyring */
618 if (keyring && link_ret == 0)
619 __key_link(keyring, key, &edit);
620
621 /* disable the authorisation key */
622 if (authkey)
623 key_invalidate(authkey);
624 }
625
626 mutex_unlock(&key_construction_mutex);
627
628 if (keyring && link_ret == 0)
629 __key_link_end(keyring, &key->index_key, edit);
630
631 /* wake up anyone waiting for a key to be constructed */
632 if (awaken)
633 wake_up_bit(&key->flags, KEY_FLAG_USER_CONSTRUCT);
634
635 return ret == 0 ? link_ret : ret;
636}
637EXPORT_SYMBOL(key_reject_and_link);
638
639/**
640 * key_put - Discard a reference to a key.
641 * @key: The key to discard a reference from.
642 *
643 * Discard a reference to a key, and when all the references are gone, we
644 * schedule the cleanup task to come and pull it out of the tree in process
645 * context at some later time.
646 */
647void key_put(struct key *key)
648{
649 if (key) {
650 key_check(key);
651
652 if (refcount_dec_and_test(&key->usage))
653 schedule_work(&key_gc_work);
654 }
655}
656EXPORT_SYMBOL(key_put);
657
658/*
659 * Find a key by its serial number.
660 */
661struct key *key_lookup(key_serial_t id)
662{
663 struct rb_node *n;
664 struct key *key;
665
666 spin_lock(&key_serial_lock);
667
668 /* search the tree for the specified key */
669 n = key_serial_tree.rb_node;
670 while (n) {
671 key = rb_entry(n, struct key, serial_node);
672
673 if (id < key->serial)
674 n = n->rb_left;
675 else if (id > key->serial)
676 n = n->rb_right;
677 else
678 goto found;
679 }
680
681not_found:
682 key = ERR_PTR(-ENOKEY);
683 goto error;
684
685found:
686 /* A key is allowed to be looked up only if someone still owns a
687 * reference to it - otherwise it's awaiting the gc.
688 */
689 if (!refcount_inc_not_zero(&key->usage))
690 goto not_found;
691
692error:
693 spin_unlock(&key_serial_lock);
694 return key;
695}
696
697/*
698 * Find and lock the specified key type against removal.
699 *
700 * We return with the sem read-locked if successful. If the type wasn't
701 * available -ENOKEY is returned instead.
702 */
703struct key_type *key_type_lookup(const char *type)
704{
705 struct key_type *ktype;
706
707 down_read(&key_types_sem);
708
709 /* look up the key type to see if it's one of the registered kernel
710 * types */
711 list_for_each_entry(ktype, &key_types_list, link) {
712 if (strcmp(ktype->name, type) == 0)
713 goto found_kernel_type;
714 }
715
716 up_read(&key_types_sem);
717 ktype = ERR_PTR(-ENOKEY);
718
719found_kernel_type:
720 return ktype;
721}
722
723void key_set_timeout(struct key *key, unsigned timeout)
724{
725 time64_t expiry = 0;
726
727 /* make the changes with the locks held to prevent races */
728 down_write(&key->sem);
729
730 if (timeout > 0)
731 expiry = ktime_get_real_seconds() + timeout;
732
733 key->expiry = expiry;
734 key_schedule_gc(key->expiry + key_gc_delay);
735
736 up_write(&key->sem);
737}
738EXPORT_SYMBOL_GPL(key_set_timeout);
739
740/*
741 * Unlock a key type locked by key_type_lookup().
742 */
743void key_type_put(struct key_type *ktype)
744{
745 up_read(&key_types_sem);
746}
747
748/*
749 * Attempt to update an existing key.
750 *
751 * The key is given to us with an incremented refcount that we need to discard
752 * if we get an error.
753 */
754static inline key_ref_t __key_update(key_ref_t key_ref,
755 struct key_preparsed_payload *prep)
756{
757 struct key *key = key_ref_to_ptr(key_ref);
758 int ret;
759
760 /* need write permission on the key to update it */
761 ret = key_permission(key_ref, KEY_NEED_WRITE);
762 if (ret < 0)
763 goto error;
764
765 ret = -EEXIST;
766 if (!key->type->update)
767 goto error;
768
769 down_write(&key->sem);
770
771 ret = key->type->update(key, prep);
772 if (ret == 0) {
773 /* Updating a negative key positively instantiates it */
774 mark_key_instantiated(key, 0);
775 notify_key(key, NOTIFY_KEY_UPDATED, 0);
776 }
777
778 up_write(&key->sem);
779
780 if (ret < 0)
781 goto error;
782out:
783 return key_ref;
784
785error:
786 key_put(key);
787 key_ref = ERR_PTR(ret);
788 goto out;
789}
790
791/**
792 * key_create_or_update - Update or create and instantiate a key.
793 * @keyring_ref: A pointer to the destination keyring with possession flag.
794 * @type: The type of key.
795 * @description: The searchable description for the key.
796 * @payload: The data to use to instantiate or update the key.
797 * @plen: The length of @payload.
798 * @perm: The permissions mask for a new key.
799 * @flags: The quota flags for a new key.
800 *
801 * Search the destination keyring for a key of the same description and if one
802 * is found, update it, otherwise create and instantiate a new one and create a
803 * link to it from that keyring.
804 *
805 * If perm is KEY_PERM_UNDEF then an appropriate key permissions mask will be
806 * concocted.
807 *
808 * Returns a pointer to the new key if successful, -ENODEV if the key type
809 * wasn't available, -ENOTDIR if the keyring wasn't a keyring, -EACCES if the
810 * caller isn't permitted to modify the keyring or the LSM did not permit
811 * creation of the key.
812 *
813 * On success, the possession flag from the keyring ref will be tacked on to
814 * the key ref before it is returned.
815 */
816key_ref_t key_create_or_update(key_ref_t keyring_ref,
817 const char *type,
818 const char *description,
819 const void *payload,
820 size_t plen,
821 key_perm_t perm,
822 unsigned long flags)
823{
824 struct keyring_index_key index_key = {
825 .description = description,
826 };
827 struct key_preparsed_payload prep;
828 struct assoc_array_edit *edit = NULL;
829 const struct cred *cred = current_cred();
830 struct key *keyring, *key = NULL;
831 key_ref_t key_ref;
832 int ret;
833 struct key_restriction *restrict_link = NULL;
834
835 /* look up the key type to see if it's one of the registered kernel
836 * types */
837 index_key.type = key_type_lookup(type);
838 if (IS_ERR(index_key.type)) {
839 key_ref = ERR_PTR(-ENODEV);
840 goto error;
841 }
842
843 key_ref = ERR_PTR(-EINVAL);
844 if (!index_key.type->instantiate ||
845 (!index_key.description && !index_key.type->preparse))
846 goto error_put_type;
847
848 keyring = key_ref_to_ptr(keyring_ref);
849
850 key_check(keyring);
851
852 if (!(flags & KEY_ALLOC_BYPASS_RESTRICTION))
853 restrict_link = keyring->restrict_link;
854
855 key_ref = ERR_PTR(-ENOTDIR);
856 if (keyring->type != &key_type_keyring)
857 goto error_put_type;
858
859 memset(&prep, 0, sizeof(prep));
860 prep.orig_description = description;
861 prep.data = payload;
862 prep.datalen = plen;
863 prep.quotalen = index_key.type->def_datalen;
864 prep.expiry = TIME64_MAX;
865 if (index_key.type->preparse) {
866 ret = index_key.type->preparse(&prep);
867 if (ret < 0) {
868 key_ref = ERR_PTR(ret);
869 goto error_free_prep;
870 }
871 if (!index_key.description)
872 index_key.description = prep.description;
873 key_ref = ERR_PTR(-EINVAL);
874 if (!index_key.description)
875 goto error_free_prep;
876 }
877 index_key.desc_len = strlen(index_key.description);
878 key_set_index_key(&index_key);
879
880 ret = __key_link_lock(keyring, &index_key);
881 if (ret < 0) {
882 key_ref = ERR_PTR(ret);
883 goto error_free_prep;
884 }
885
886 ret = __key_link_begin(keyring, &index_key, &edit);
887 if (ret < 0) {
888 key_ref = ERR_PTR(ret);
889 goto error_link_end;
890 }
891
892 if (restrict_link && restrict_link->check) {
893 ret = restrict_link->check(keyring, index_key.type,
894 &prep.payload, restrict_link->key);
895 if (ret < 0) {
896 key_ref = ERR_PTR(ret);
897 goto error_link_end;
898 }
899 }
900
901 /* if we're going to allocate a new key, we're going to have
902 * to modify the keyring */
903 ret = key_permission(keyring_ref, KEY_NEED_WRITE);
904 if (ret < 0) {
905 key_ref = ERR_PTR(ret);
906 goto error_link_end;
907 }
908
909 /* if it's possible to update this type of key, search for an existing
910 * key of the same type and description in the destination keyring and
911 * update that instead if possible
912 */
913 if (index_key.type->update) {
914 key_ref = find_key_to_update(keyring_ref, &index_key);
915 if (key_ref)
916 goto found_matching_key;
917 }
918
919 /* if the client doesn't provide, decide on the permissions we want */
920 if (perm == KEY_PERM_UNDEF) {
921 perm = KEY_POS_VIEW | KEY_POS_SEARCH | KEY_POS_LINK | KEY_POS_SETATTR;
922 perm |= KEY_USR_VIEW;
923
924 if (index_key.type->read)
925 perm |= KEY_POS_READ;
926
927 if (index_key.type == &key_type_keyring ||
928 index_key.type->update)
929 perm |= KEY_POS_WRITE;
930 }
931
932 /* allocate a new key */
933 key = key_alloc(index_key.type, index_key.description,
934 cred->fsuid, cred->fsgid, cred, perm, flags, NULL);
935 if (IS_ERR(key)) {
936 key_ref = ERR_CAST(key);
937 goto error_link_end;
938 }
939
940 /* instantiate it and link it into the target keyring */
941 ret = __key_instantiate_and_link(key, &prep, keyring, NULL, &edit);
942 if (ret < 0) {
943 key_put(key);
944 key_ref = ERR_PTR(ret);
945 goto error_link_end;
946 }
947
948 ima_post_key_create_or_update(keyring, key, payload, plen,
949 flags, true);
950
951 key_ref = make_key_ref(key, is_key_possessed(keyring_ref));
952
953error_link_end:
954 __key_link_end(keyring, &index_key, edit);
955error_free_prep:
956 if (index_key.type->preparse)
957 index_key.type->free_preparse(&prep);
958error_put_type:
959 key_type_put(index_key.type);
960error:
961 return key_ref;
962
963 found_matching_key:
964 /* we found a matching key, so we're going to try to update it
965 * - we can drop the locks first as we have the key pinned
966 */
967 __key_link_end(keyring, &index_key, edit);
968
969 key = key_ref_to_ptr(key_ref);
970 if (test_bit(KEY_FLAG_USER_CONSTRUCT, &key->flags)) {
971 ret = wait_for_key_construction(key, true);
972 if (ret < 0) {
973 key_ref_put(key_ref);
974 key_ref = ERR_PTR(ret);
975 goto error_free_prep;
976 }
977 }
978
979 key_ref = __key_update(key_ref, &prep);
980
981 if (!IS_ERR(key_ref))
982 ima_post_key_create_or_update(keyring, key,
983 payload, plen,
984 flags, false);
985
986 goto error_free_prep;
987}
988EXPORT_SYMBOL(key_create_or_update);
989
990/**
991 * key_update - Update a key's contents.
992 * @key_ref: The pointer (plus possession flag) to the key.
993 * @payload: The data to be used to update the key.
994 * @plen: The length of @payload.
995 *
996 * Attempt to update the contents of a key with the given payload data. The
997 * caller must be granted Write permission on the key. Negative keys can be
998 * instantiated by this method.
999 *
1000 * Returns 0 on success, -EACCES if not permitted and -EOPNOTSUPP if the key
1001 * type does not support updating. The key type may return other errors.
1002 */
1003int key_update(key_ref_t key_ref, const void *payload, size_t plen)
1004{
1005 struct key_preparsed_payload prep;
1006 struct key *key = key_ref_to_ptr(key_ref);
1007 int ret;
1008
1009 key_check(key);
1010
1011 /* the key must be writable */
1012 ret = key_permission(key_ref, KEY_NEED_WRITE);
1013 if (ret < 0)
1014 return ret;
1015
1016 /* attempt to update it if supported */
1017 if (!key->type->update)
1018 return -EOPNOTSUPP;
1019
1020 memset(&prep, 0, sizeof(prep));
1021 prep.data = payload;
1022 prep.datalen = plen;
1023 prep.quotalen = key->type->def_datalen;
1024 prep.expiry = TIME64_MAX;
1025 if (key->type->preparse) {
1026 ret = key->type->preparse(&prep);
1027 if (ret < 0)
1028 goto error;
1029 }
1030
1031 down_write(&key->sem);
1032
1033 ret = key->type->update(key, &prep);
1034 if (ret == 0) {
1035 /* Updating a negative key positively instantiates it */
1036 mark_key_instantiated(key, 0);
1037 notify_key(key, NOTIFY_KEY_UPDATED, 0);
1038 }
1039
1040 up_write(&key->sem);
1041
1042error:
1043 if (key->type->preparse)
1044 key->type->free_preparse(&prep);
1045 return ret;
1046}
1047EXPORT_SYMBOL(key_update);
1048
1049/**
1050 * key_revoke - Revoke a key.
1051 * @key: The key to be revoked.
1052 *
1053 * Mark a key as being revoked and ask the type to free up its resources. The
1054 * revocation timeout is set and the key and all its links will be
1055 * automatically garbage collected after key_gc_delay amount of time if they
1056 * are not manually dealt with first.
1057 */
1058void key_revoke(struct key *key)
1059{
1060 time64_t time;
1061
1062 key_check(key);
1063
1064 /* make sure no one's trying to change or use the key when we mark it
1065 * - we tell lockdep that we might nest because we might be revoking an
1066 * authorisation key whilst holding the sem on a key we've just
1067 * instantiated
1068 */
1069 down_write_nested(&key->sem, 1);
1070 if (!test_and_set_bit(KEY_FLAG_REVOKED, &key->flags)) {
1071 notify_key(key, NOTIFY_KEY_REVOKED, 0);
1072 if (key->type->revoke)
1073 key->type->revoke(key);
1074
1075 /* set the death time to no more than the expiry time */
1076 time = ktime_get_real_seconds();
1077 if (key->revoked_at == 0 || key->revoked_at > time) {
1078 key->revoked_at = time;
1079 key_schedule_gc(key->revoked_at + key_gc_delay);
1080 }
1081 }
1082
1083 up_write(&key->sem);
1084}
1085EXPORT_SYMBOL(key_revoke);
1086
1087/**
1088 * key_invalidate - Invalidate a key.
1089 * @key: The key to be invalidated.
1090 *
1091 * Mark a key as being invalidated and have it cleaned up immediately. The key
1092 * is ignored by all searches and other operations from this point.
1093 */
1094void key_invalidate(struct key *key)
1095{
1096 kenter("%d", key_serial(key));
1097
1098 key_check(key);
1099
1100 if (!test_bit(KEY_FLAG_INVALIDATED, &key->flags)) {
1101 down_write_nested(&key->sem, 1);
1102 if (!test_and_set_bit(KEY_FLAG_INVALIDATED, &key->flags)) {
1103 notify_key(key, NOTIFY_KEY_INVALIDATED, 0);
1104 key_schedule_gc_links();
1105 }
1106 up_write(&key->sem);
1107 }
1108}
1109EXPORT_SYMBOL(key_invalidate);
1110
1111/**
1112 * generic_key_instantiate - Simple instantiation of a key from preparsed data
1113 * @key: The key to be instantiated
1114 * @prep: The preparsed data to load.
1115 *
1116 * Instantiate a key from preparsed data. We assume we can just copy the data
1117 * in directly and clear the old pointers.
1118 *
1119 * This can be pointed to directly by the key type instantiate op pointer.
1120 */
1121int generic_key_instantiate(struct key *key, struct key_preparsed_payload *prep)
1122{
1123 int ret;
1124
1125 pr_devel("==>%s()\n", __func__);
1126
1127 ret = key_payload_reserve(key, prep->quotalen);
1128 if (ret == 0) {
1129 rcu_assign_keypointer(key, prep->payload.data[0]);
1130 key->payload.data[1] = prep->payload.data[1];
1131 key->payload.data[2] = prep->payload.data[2];
1132 key->payload.data[3] = prep->payload.data[3];
1133 prep->payload.data[0] = NULL;
1134 prep->payload.data[1] = NULL;
1135 prep->payload.data[2] = NULL;
1136 prep->payload.data[3] = NULL;
1137 }
1138 pr_devel("<==%s() = %d\n", __func__, ret);
1139 return ret;
1140}
1141EXPORT_SYMBOL(generic_key_instantiate);
1142
1143/**
1144 * register_key_type - Register a type of key.
1145 * @ktype: The new key type.
1146 *
1147 * Register a new key type.
1148 *
1149 * Returns 0 on success or -EEXIST if a type of this name already exists.
1150 */
1151int register_key_type(struct key_type *ktype)
1152{
1153 struct key_type *p;
1154 int ret;
1155
1156 memset(&ktype->lock_class, 0, sizeof(ktype->lock_class));
1157
1158 ret = -EEXIST;
1159 down_write(&key_types_sem);
1160
1161 /* disallow key types with the same name */
1162 list_for_each_entry(p, &key_types_list, link) {
1163 if (strcmp(p->name, ktype->name) == 0)
1164 goto out;
1165 }
1166
1167 /* store the type */
1168 list_add(&ktype->link, &key_types_list);
1169
1170 pr_notice("Key type %s registered\n", ktype->name);
1171 ret = 0;
1172
1173out:
1174 up_write(&key_types_sem);
1175 return ret;
1176}
1177EXPORT_SYMBOL(register_key_type);
1178
1179/**
1180 * unregister_key_type - Unregister a type of key.
1181 * @ktype: The key type.
1182 *
1183 * Unregister a key type and mark all the extant keys of this type as dead.
1184 * Those keys of this type are then destroyed to get rid of their payloads and
1185 * they and their links will be garbage collected as soon as possible.
1186 */
1187void unregister_key_type(struct key_type *ktype)
1188{
1189 down_write(&key_types_sem);
1190 list_del_init(&ktype->link);
1191 downgrade_write(&key_types_sem);
1192 key_gc_keytype(ktype);
1193 pr_notice("Key type %s unregistered\n", ktype->name);
1194 up_read(&key_types_sem);
1195}
1196EXPORT_SYMBOL(unregister_key_type);
1197
1198/*
1199 * Initialise the key management state.
1200 */
1201void __init key_init(void)
1202{
1203 /* allocate a slab in which we can store keys */
1204 key_jar = kmem_cache_create("key_jar", sizeof(struct key),
1205 0, SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
1206
1207 /* add the special key types */
1208 list_add_tail(&key_type_keyring.link, &key_types_list);
1209 list_add_tail(&key_type_dead.link, &key_types_list);
1210 list_add_tail(&key_type_user.link, &key_types_list);
1211 list_add_tail(&key_type_logon.link, &key_types_list);
1212
1213 /* record the root user tracking */
1214 rb_link_node(&root_key_user.node,
1215 NULL,
1216 &key_user_tree.rb_node);
1217
1218 rb_insert_color(&root_key_user.node,
1219 &key_user_tree);
1220}
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->restrict_link = restrict_link;
297 key->last_used_at = ktime_get_real_seconds();
298
299 if (!(flags & KEY_ALLOC_NOT_IN_QUOTA))
300 key->flags |= 1 << KEY_FLAG_IN_QUOTA;
301 if (flags & KEY_ALLOC_BUILT_IN)
302 key->flags |= 1 << KEY_FLAG_BUILTIN;
303 if (flags & KEY_ALLOC_UID_KEYRING)
304 key->flags |= 1 << KEY_FLAG_UID_KEYRING;
305
306#ifdef KEY_DEBUGGING
307 key->magic = KEY_DEBUG_MAGIC;
308#endif
309
310 /* let the security module know about the key */
311 ret = security_key_alloc(key, cred, flags);
312 if (ret < 0)
313 goto security_error;
314
315 /* publish the key by giving it a serial number */
316 refcount_inc(&key->domain_tag->usage);
317 atomic_inc(&user->nkeys);
318 key_alloc_serial(key);
319
320error:
321 return key;
322
323security_error:
324 kfree(key->description);
325 kmem_cache_free(key_jar, key);
326 if (!(flags & KEY_ALLOC_NOT_IN_QUOTA)) {
327 spin_lock(&user->lock);
328 user->qnkeys--;
329 user->qnbytes -= quotalen;
330 spin_unlock(&user->lock);
331 }
332 key_user_put(user);
333 key = ERR_PTR(ret);
334 goto error;
335
336no_memory_3:
337 kmem_cache_free(key_jar, key);
338no_memory_2:
339 if (!(flags & KEY_ALLOC_NOT_IN_QUOTA)) {
340 spin_lock(&user->lock);
341 user->qnkeys--;
342 user->qnbytes -= quotalen;
343 spin_unlock(&user->lock);
344 }
345 key_user_put(user);
346no_memory_1:
347 key = ERR_PTR(-ENOMEM);
348 goto error;
349
350no_quota:
351 spin_unlock(&user->lock);
352 key_user_put(user);
353 key = ERR_PTR(-EDQUOT);
354 goto error;
355}
356EXPORT_SYMBOL(key_alloc);
357
358/**
359 * key_payload_reserve - Adjust data quota reservation for the key's payload
360 * @key: The key to make the reservation for.
361 * @datalen: The amount of data payload the caller now wants.
362 *
363 * Adjust the amount of the owning user's key data quota that a key reserves.
364 * If the amount is increased, then -EDQUOT may be returned if there isn't
365 * enough free quota available.
366 *
367 * If successful, 0 is returned.
368 */
369int key_payload_reserve(struct key *key, size_t datalen)
370{
371 int delta = (int)datalen - key->datalen;
372 int ret = 0;
373
374 key_check(key);
375
376 /* contemplate the quota adjustment */
377 if (delta != 0 && test_bit(KEY_FLAG_IN_QUOTA, &key->flags)) {
378 unsigned maxbytes = uid_eq(key->user->uid, GLOBAL_ROOT_UID) ?
379 key_quota_root_maxbytes : key_quota_maxbytes;
380
381 spin_lock(&key->user->lock);
382
383 if (delta > 0 &&
384 (key->user->qnbytes + delta >= maxbytes ||
385 key->user->qnbytes + delta < key->user->qnbytes)) {
386 ret = -EDQUOT;
387 }
388 else {
389 key->user->qnbytes += delta;
390 key->quotalen += delta;
391 }
392 spin_unlock(&key->user->lock);
393 }
394
395 /* change the recorded data length if that didn't generate an error */
396 if (ret == 0)
397 key->datalen = datalen;
398
399 return ret;
400}
401EXPORT_SYMBOL(key_payload_reserve);
402
403/*
404 * Change the key state to being instantiated.
405 */
406static void mark_key_instantiated(struct key *key, int reject_error)
407{
408 /* Commit the payload before setting the state; barrier versus
409 * key_read_state().
410 */
411 smp_store_release(&key->state,
412 (reject_error < 0) ? reject_error : KEY_IS_POSITIVE);
413}
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 struct key_preparsed_payload *prep,
423 struct key *keyring,
424 struct key *authkey,
425 struct assoc_array_edit **_edit)
426{
427 int ret, awaken;
428
429 key_check(key);
430 key_check(keyring);
431
432 awaken = 0;
433 ret = -EBUSY;
434
435 mutex_lock(&key_construction_mutex);
436
437 /* can't instantiate twice */
438 if (key->state == KEY_IS_UNINSTANTIATED) {
439 /* instantiate the key */
440 ret = key->type->instantiate(key, prep);
441
442 if (ret == 0) {
443 /* mark the key as being instantiated */
444 atomic_inc(&key->user->nikeys);
445 mark_key_instantiated(key, 0);
446
447 if (test_and_clear_bit(KEY_FLAG_USER_CONSTRUCT, &key->flags))
448 awaken = 1;
449
450 /* and link it into the destination keyring */
451 if (keyring) {
452 if (test_bit(KEY_FLAG_KEEP, &keyring->flags))
453 set_bit(KEY_FLAG_KEEP, &key->flags);
454
455 __key_link(key, _edit);
456 }
457
458 /* disable the authorisation key */
459 if (authkey)
460 key_invalidate(authkey);
461
462 if (prep->expiry != TIME64_MAX) {
463 key->expiry = prep->expiry;
464 key_schedule_gc(prep->expiry + key_gc_delay);
465 }
466 }
467 }
468
469 mutex_unlock(&key_construction_mutex);
470
471 /* wake up anyone waiting for a key to be constructed */
472 if (awaken)
473 wake_up_bit(&key->flags, KEY_FLAG_USER_CONSTRUCT);
474
475 return ret;
476}
477
478/**
479 * key_instantiate_and_link - Instantiate a key and link it into the keyring.
480 * @key: The key to instantiate.
481 * @data: The data to use to instantiate the keyring.
482 * @datalen: The length of @data.
483 * @keyring: Keyring to create a link in on success (or NULL).
484 * @authkey: The authorisation token permitting instantiation.
485 *
486 * Instantiate a key that's in the uninstantiated state using the provided data
487 * and, if successful, link it in to the destination keyring if one is
488 * supplied.
489 *
490 * If successful, 0 is returned, the authorisation token is revoked and anyone
491 * waiting for the key is woken up. If the key was already instantiated,
492 * -EBUSY will be returned.
493 */
494int key_instantiate_and_link(struct key *key,
495 const void *data,
496 size_t datalen,
497 struct key *keyring,
498 struct key *authkey)
499{
500 struct key_preparsed_payload prep;
501 struct assoc_array_edit *edit = NULL;
502 int ret;
503
504 memset(&prep, 0, sizeof(prep));
505 prep.data = data;
506 prep.datalen = datalen;
507 prep.quotalen = key->type->def_datalen;
508 prep.expiry = TIME64_MAX;
509 if (key->type->preparse) {
510 ret = key->type->preparse(&prep);
511 if (ret < 0)
512 goto error;
513 }
514
515 if (keyring) {
516 ret = __key_link_lock(keyring, &key->index_key);
517 if (ret < 0)
518 goto error;
519
520 ret = __key_link_begin(keyring, &key->index_key, &edit);
521 if (ret < 0)
522 goto error_link_end;
523
524 if (keyring->restrict_link && keyring->restrict_link->check) {
525 struct key_restriction *keyres = keyring->restrict_link;
526
527 ret = keyres->check(keyring, key->type, &prep.payload,
528 keyres->key);
529 if (ret < 0)
530 goto error_link_end;
531 }
532 }
533
534 ret = __key_instantiate_and_link(key, &prep, keyring, authkey, &edit);
535
536error_link_end:
537 if (keyring)
538 __key_link_end(keyring, &key->index_key, edit);
539
540error:
541 if (key->type->preparse)
542 key->type->free_preparse(&prep);
543 return ret;
544}
545
546EXPORT_SYMBOL(key_instantiate_and_link);
547
548/**
549 * key_reject_and_link - Negatively instantiate a key and link it into the keyring.
550 * @key: The key to instantiate.
551 * @timeout: The timeout on the negative key.
552 * @error: The error to return when the key is hit.
553 * @keyring: Keyring to create a link in on success (or NULL).
554 * @authkey: The authorisation token permitting instantiation.
555 *
556 * Negatively instantiate a key that's in the uninstantiated state and, if
557 * successful, set its timeout and stored error and link it in to the
558 * destination keyring if one is supplied. The key and any links to the key
559 * will be automatically garbage collected after the timeout expires.
560 *
561 * Negative keys are used to rate limit repeated request_key() calls by causing
562 * them to return the stored error code (typically ENOKEY) until the negative
563 * key expires.
564 *
565 * If successful, 0 is returned, the authorisation token is revoked and anyone
566 * waiting for the key is woken up. If the key was already instantiated,
567 * -EBUSY will be returned.
568 */
569int key_reject_and_link(struct key *key,
570 unsigned timeout,
571 unsigned error,
572 struct key *keyring,
573 struct key *authkey)
574{
575 struct assoc_array_edit *edit = NULL;
576 int ret, awaken, link_ret = 0;
577
578 key_check(key);
579 key_check(keyring);
580
581 awaken = 0;
582 ret = -EBUSY;
583
584 if (keyring) {
585 if (keyring->restrict_link)
586 return -EPERM;
587
588 link_ret = __key_link_lock(keyring, &key->index_key);
589 if (link_ret == 0) {
590 link_ret = __key_link_begin(keyring, &key->index_key, &edit);
591 if (link_ret < 0)
592 __key_link_end(keyring, &key->index_key, edit);
593 }
594 }
595
596 mutex_lock(&key_construction_mutex);
597
598 /* can't instantiate twice */
599 if (key->state == KEY_IS_UNINSTANTIATED) {
600 /* mark the key as being negatively instantiated */
601 atomic_inc(&key->user->nikeys);
602 mark_key_instantiated(key, -error);
603 key->expiry = ktime_get_real_seconds() + timeout;
604 key_schedule_gc(key->expiry + key_gc_delay);
605
606 if (test_and_clear_bit(KEY_FLAG_USER_CONSTRUCT, &key->flags))
607 awaken = 1;
608
609 ret = 0;
610
611 /* and link it into the destination keyring */
612 if (keyring && link_ret == 0)
613 __key_link(key, &edit);
614
615 /* disable the authorisation key */
616 if (authkey)
617 key_invalidate(authkey);
618 }
619
620 mutex_unlock(&key_construction_mutex);
621
622 if (keyring && link_ret == 0)
623 __key_link_end(keyring, &key->index_key, edit);
624
625 /* wake up anyone waiting for a key to be constructed */
626 if (awaken)
627 wake_up_bit(&key->flags, KEY_FLAG_USER_CONSTRUCT);
628
629 return ret == 0 ? link_ret : ret;
630}
631EXPORT_SYMBOL(key_reject_and_link);
632
633/**
634 * key_put - Discard a reference to a key.
635 * @key: The key to discard a reference from.
636 *
637 * Discard a reference to a key, and when all the references are gone, we
638 * schedule the cleanup task to come and pull it out of the tree in process
639 * context at some later time.
640 */
641void key_put(struct key *key)
642{
643 if (key) {
644 key_check(key);
645
646 if (refcount_dec_and_test(&key->usage))
647 schedule_work(&key_gc_work);
648 }
649}
650EXPORT_SYMBOL(key_put);
651
652/*
653 * Find a key by its serial number.
654 */
655struct key *key_lookup(key_serial_t id)
656{
657 struct rb_node *n;
658 struct key *key;
659
660 spin_lock(&key_serial_lock);
661
662 /* search the tree for the specified key */
663 n = key_serial_tree.rb_node;
664 while (n) {
665 key = rb_entry(n, struct key, serial_node);
666
667 if (id < key->serial)
668 n = n->rb_left;
669 else if (id > key->serial)
670 n = n->rb_right;
671 else
672 goto found;
673 }
674
675not_found:
676 key = ERR_PTR(-ENOKEY);
677 goto error;
678
679found:
680 /* A key is allowed to be looked up only if someone still owns a
681 * reference to it - otherwise it's awaiting the gc.
682 */
683 if (!refcount_inc_not_zero(&key->usage))
684 goto not_found;
685
686error:
687 spin_unlock(&key_serial_lock);
688 return key;
689}
690
691/*
692 * Find and lock the specified key type against removal.
693 *
694 * We return with the sem read-locked if successful. If the type wasn't
695 * available -ENOKEY is returned instead.
696 */
697struct key_type *key_type_lookup(const char *type)
698{
699 struct key_type *ktype;
700
701 down_read(&key_types_sem);
702
703 /* look up the key type to see if it's one of the registered kernel
704 * types */
705 list_for_each_entry(ktype, &key_types_list, link) {
706 if (strcmp(ktype->name, type) == 0)
707 goto found_kernel_type;
708 }
709
710 up_read(&key_types_sem);
711 ktype = ERR_PTR(-ENOKEY);
712
713found_kernel_type:
714 return ktype;
715}
716
717void key_set_timeout(struct key *key, unsigned timeout)
718{
719 time64_t expiry = 0;
720
721 /* make the changes with the locks held to prevent races */
722 down_write(&key->sem);
723
724 if (timeout > 0)
725 expiry = ktime_get_real_seconds() + timeout;
726
727 key->expiry = expiry;
728 key_schedule_gc(key->expiry + key_gc_delay);
729
730 up_write(&key->sem);
731}
732EXPORT_SYMBOL_GPL(key_set_timeout);
733
734/*
735 * Unlock a key type locked by key_type_lookup().
736 */
737void key_type_put(struct key_type *ktype)
738{
739 up_read(&key_types_sem);
740}
741
742/*
743 * Attempt to update an existing key.
744 *
745 * The key is given to us with an incremented refcount that we need to discard
746 * if we get an error.
747 */
748static inline key_ref_t __key_update(key_ref_t key_ref,
749 struct key_preparsed_payload *prep)
750{
751 struct key *key = key_ref_to_ptr(key_ref);
752 int ret;
753
754 /* need write permission on the key to update it */
755 ret = key_permission(key_ref, KEY_NEED_WRITE);
756 if (ret < 0)
757 goto error;
758
759 ret = -EEXIST;
760 if (!key->type->update)
761 goto error;
762
763 down_write(&key->sem);
764
765 ret = key->type->update(key, prep);
766 if (ret == 0)
767 /* Updating a negative key positively instantiates it */
768 mark_key_instantiated(key, 0);
769
770 up_write(&key->sem);
771
772 if (ret < 0)
773 goto error;
774out:
775 return key_ref;
776
777error:
778 key_put(key);
779 key_ref = ERR_PTR(ret);
780 goto out;
781}
782
783/**
784 * key_create_or_update - Update or create and instantiate a key.
785 * @keyring_ref: A pointer to the destination keyring with possession flag.
786 * @type: The type of key.
787 * @description: The searchable description for the key.
788 * @payload: The data to use to instantiate or update the key.
789 * @plen: The length of @payload.
790 * @perm: The permissions mask for a new key.
791 * @flags: The quota flags for a new key.
792 *
793 * Search the destination keyring for a key of the same description and if one
794 * is found, update it, otherwise create and instantiate a new one and create a
795 * link to it from that keyring.
796 *
797 * If perm is KEY_PERM_UNDEF then an appropriate key permissions mask will be
798 * concocted.
799 *
800 * Returns a pointer to the new key if successful, -ENODEV if the key type
801 * wasn't available, -ENOTDIR if the keyring wasn't a keyring, -EACCES if the
802 * caller isn't permitted to modify the keyring or the LSM did not permit
803 * creation of the key.
804 *
805 * On success, the possession flag from the keyring ref will be tacked on to
806 * the key ref before it is returned.
807 */
808key_ref_t key_create_or_update(key_ref_t keyring_ref,
809 const char *type,
810 const char *description,
811 const void *payload,
812 size_t plen,
813 key_perm_t perm,
814 unsigned long flags)
815{
816 struct keyring_index_key index_key = {
817 .description = description,
818 };
819 struct key_preparsed_payload prep;
820 struct assoc_array_edit *edit = NULL;
821 const struct cred *cred = current_cred();
822 struct key *keyring, *key = NULL;
823 key_ref_t key_ref;
824 int ret;
825 struct key_restriction *restrict_link = NULL;
826
827 /* look up the key type to see if it's one of the registered kernel
828 * types */
829 index_key.type = key_type_lookup(type);
830 if (IS_ERR(index_key.type)) {
831 key_ref = ERR_PTR(-ENODEV);
832 goto error;
833 }
834
835 key_ref = ERR_PTR(-EINVAL);
836 if (!index_key.type->instantiate ||
837 (!index_key.description && !index_key.type->preparse))
838 goto error_put_type;
839
840 keyring = key_ref_to_ptr(keyring_ref);
841
842 key_check(keyring);
843
844 if (!(flags & KEY_ALLOC_BYPASS_RESTRICTION))
845 restrict_link = keyring->restrict_link;
846
847 key_ref = ERR_PTR(-ENOTDIR);
848 if (keyring->type != &key_type_keyring)
849 goto error_put_type;
850
851 memset(&prep, 0, sizeof(prep));
852 prep.data = payload;
853 prep.datalen = plen;
854 prep.quotalen = index_key.type->def_datalen;
855 prep.expiry = TIME64_MAX;
856 if (index_key.type->preparse) {
857 ret = index_key.type->preparse(&prep);
858 if (ret < 0) {
859 key_ref = ERR_PTR(ret);
860 goto error_free_prep;
861 }
862 if (!index_key.description)
863 index_key.description = prep.description;
864 key_ref = ERR_PTR(-EINVAL);
865 if (!index_key.description)
866 goto error_free_prep;
867 }
868 index_key.desc_len = strlen(index_key.description);
869 key_set_index_key(&index_key);
870
871 ret = __key_link_lock(keyring, &index_key);
872 if (ret < 0) {
873 key_ref = ERR_PTR(ret);
874 goto error_free_prep;
875 }
876
877 ret = __key_link_begin(keyring, &index_key, &edit);
878 if (ret < 0) {
879 key_ref = ERR_PTR(ret);
880 goto error_link_end;
881 }
882
883 if (restrict_link && restrict_link->check) {
884 ret = restrict_link->check(keyring, index_key.type,
885 &prep.payload, restrict_link->key);
886 if (ret < 0) {
887 key_ref = ERR_PTR(ret);
888 goto error_link_end;
889 }
890 }
891
892 /* if we're going to allocate a new key, we're going to have
893 * to modify the keyring */
894 ret = key_permission(keyring_ref, KEY_NEED_WRITE);
895 if (ret < 0) {
896 key_ref = ERR_PTR(ret);
897 goto error_link_end;
898 }
899
900 /* if it's possible to update this type of key, search for an existing
901 * key of the same type and description in the destination keyring and
902 * update that instead if possible
903 */
904 if (index_key.type->update) {
905 key_ref = find_key_to_update(keyring_ref, &index_key);
906 if (key_ref)
907 goto found_matching_key;
908 }
909
910 /* if the client doesn't provide, decide on the permissions we want */
911 if (perm == KEY_PERM_UNDEF) {
912 perm = KEY_POS_VIEW | KEY_POS_SEARCH | KEY_POS_LINK | KEY_POS_SETATTR;
913 perm |= KEY_USR_VIEW;
914
915 if (index_key.type->read)
916 perm |= KEY_POS_READ;
917
918 if (index_key.type == &key_type_keyring ||
919 index_key.type->update)
920 perm |= KEY_POS_WRITE;
921 }
922
923 /* allocate a new key */
924 key = key_alloc(index_key.type, index_key.description,
925 cred->fsuid, cred->fsgid, cred, perm, flags, NULL);
926 if (IS_ERR(key)) {
927 key_ref = ERR_CAST(key);
928 goto error_link_end;
929 }
930
931 /* instantiate it and link it into the target keyring */
932 ret = __key_instantiate_and_link(key, &prep, keyring, NULL, &edit);
933 if (ret < 0) {
934 key_put(key);
935 key_ref = ERR_PTR(ret);
936 goto error_link_end;
937 }
938
939 key_ref = make_key_ref(key, is_key_possessed(keyring_ref));
940
941error_link_end:
942 __key_link_end(keyring, &index_key, edit);
943error_free_prep:
944 if (index_key.type->preparse)
945 index_key.type->free_preparse(&prep);
946error_put_type:
947 key_type_put(index_key.type);
948error:
949 return key_ref;
950
951 found_matching_key:
952 /* we found a matching key, so we're going to try to update it
953 * - we can drop the locks first as we have the key pinned
954 */
955 __key_link_end(keyring, &index_key, edit);
956
957 key = key_ref_to_ptr(key_ref);
958 if (test_bit(KEY_FLAG_USER_CONSTRUCT, &key->flags)) {
959 ret = wait_for_key_construction(key, true);
960 if (ret < 0) {
961 key_ref_put(key_ref);
962 key_ref = ERR_PTR(ret);
963 goto error_free_prep;
964 }
965 }
966
967 key_ref = __key_update(key_ref, &prep);
968 goto error_free_prep;
969}
970EXPORT_SYMBOL(key_create_or_update);
971
972/**
973 * key_update - Update a key's contents.
974 * @key_ref: The pointer (plus possession flag) to the key.
975 * @payload: The data to be used to update the key.
976 * @plen: The length of @payload.
977 *
978 * Attempt to update the contents of a key with the given payload data. The
979 * caller must be granted Write permission on the key. Negative keys can be
980 * instantiated by this method.
981 *
982 * Returns 0 on success, -EACCES if not permitted and -EOPNOTSUPP if the key
983 * type does not support updating. The key type may return other errors.
984 */
985int key_update(key_ref_t key_ref, const void *payload, size_t plen)
986{
987 struct key_preparsed_payload prep;
988 struct key *key = key_ref_to_ptr(key_ref);
989 int ret;
990
991 key_check(key);
992
993 /* the key must be writable */
994 ret = key_permission(key_ref, KEY_NEED_WRITE);
995 if (ret < 0)
996 return ret;
997
998 /* attempt to update it if supported */
999 if (!key->type->update)
1000 return -EOPNOTSUPP;
1001
1002 memset(&prep, 0, sizeof(prep));
1003 prep.data = payload;
1004 prep.datalen = plen;
1005 prep.quotalen = key->type->def_datalen;
1006 prep.expiry = TIME64_MAX;
1007 if (key->type->preparse) {
1008 ret = key->type->preparse(&prep);
1009 if (ret < 0)
1010 goto error;
1011 }
1012
1013 down_write(&key->sem);
1014
1015 ret = key->type->update(key, &prep);
1016 if (ret == 0)
1017 /* Updating a negative key positively instantiates it */
1018 mark_key_instantiated(key, 0);
1019
1020 up_write(&key->sem);
1021
1022error:
1023 if (key->type->preparse)
1024 key->type->free_preparse(&prep);
1025 return ret;
1026}
1027EXPORT_SYMBOL(key_update);
1028
1029/**
1030 * key_revoke - Revoke a key.
1031 * @key: The key to be revoked.
1032 *
1033 * Mark a key as being revoked and ask the type to free up its resources. The
1034 * revocation timeout is set and the key and all its links will be
1035 * automatically garbage collected after key_gc_delay amount of time if they
1036 * are not manually dealt with first.
1037 */
1038void key_revoke(struct key *key)
1039{
1040 time64_t time;
1041
1042 key_check(key);
1043
1044 /* make sure no one's trying to change or use the key when we mark it
1045 * - we tell lockdep that we might nest because we might be revoking an
1046 * authorisation key whilst holding the sem on a key we've just
1047 * instantiated
1048 */
1049 down_write_nested(&key->sem, 1);
1050 if (!test_and_set_bit(KEY_FLAG_REVOKED, &key->flags) &&
1051 key->type->revoke)
1052 key->type->revoke(key);
1053
1054 /* set the death time to no more than the expiry time */
1055 time = ktime_get_real_seconds();
1056 if (key->revoked_at == 0 || key->revoked_at > time) {
1057 key->revoked_at = time;
1058 key_schedule_gc(key->revoked_at + key_gc_delay);
1059 }
1060
1061 up_write(&key->sem);
1062}
1063EXPORT_SYMBOL(key_revoke);
1064
1065/**
1066 * key_invalidate - Invalidate a key.
1067 * @key: The key to be invalidated.
1068 *
1069 * Mark a key as being invalidated and have it cleaned up immediately. The key
1070 * is ignored by all searches and other operations from this point.
1071 */
1072void key_invalidate(struct key *key)
1073{
1074 kenter("%d", key_serial(key));
1075
1076 key_check(key);
1077
1078 if (!test_bit(KEY_FLAG_INVALIDATED, &key->flags)) {
1079 down_write_nested(&key->sem, 1);
1080 if (!test_and_set_bit(KEY_FLAG_INVALIDATED, &key->flags))
1081 key_schedule_gc_links();
1082 up_write(&key->sem);
1083 }
1084}
1085EXPORT_SYMBOL(key_invalidate);
1086
1087/**
1088 * generic_key_instantiate - Simple instantiation of a key from preparsed data
1089 * @key: The key to be instantiated
1090 * @prep: The preparsed data to load.
1091 *
1092 * Instantiate a key from preparsed data. We assume we can just copy the data
1093 * in directly and clear the old pointers.
1094 *
1095 * This can be pointed to directly by the key type instantiate op pointer.
1096 */
1097int generic_key_instantiate(struct key *key, struct key_preparsed_payload *prep)
1098{
1099 int ret;
1100
1101 pr_devel("==>%s()\n", __func__);
1102
1103 ret = key_payload_reserve(key, prep->quotalen);
1104 if (ret == 0) {
1105 rcu_assign_keypointer(key, prep->payload.data[0]);
1106 key->payload.data[1] = prep->payload.data[1];
1107 key->payload.data[2] = prep->payload.data[2];
1108 key->payload.data[3] = prep->payload.data[3];
1109 prep->payload.data[0] = NULL;
1110 prep->payload.data[1] = NULL;
1111 prep->payload.data[2] = NULL;
1112 prep->payload.data[3] = NULL;
1113 }
1114 pr_devel("<==%s() = %d\n", __func__, ret);
1115 return ret;
1116}
1117EXPORT_SYMBOL(generic_key_instantiate);
1118
1119/**
1120 * register_key_type - Register a type of key.
1121 * @ktype: The new key type.
1122 *
1123 * Register a new key type.
1124 *
1125 * Returns 0 on success or -EEXIST if a type of this name already exists.
1126 */
1127int register_key_type(struct key_type *ktype)
1128{
1129 struct key_type *p;
1130 int ret;
1131
1132 memset(&ktype->lock_class, 0, sizeof(ktype->lock_class));
1133
1134 ret = -EEXIST;
1135 down_write(&key_types_sem);
1136
1137 /* disallow key types with the same name */
1138 list_for_each_entry(p, &key_types_list, link) {
1139 if (strcmp(p->name, ktype->name) == 0)
1140 goto out;
1141 }
1142
1143 /* store the type */
1144 list_add(&ktype->link, &key_types_list);
1145
1146 pr_notice("Key type %s registered\n", ktype->name);
1147 ret = 0;
1148
1149out:
1150 up_write(&key_types_sem);
1151 return ret;
1152}
1153EXPORT_SYMBOL(register_key_type);
1154
1155/**
1156 * unregister_key_type - Unregister a type of key.
1157 * @ktype: The key type.
1158 *
1159 * Unregister a key type and mark all the extant keys of this type as dead.
1160 * Those keys of this type are then destroyed to get rid of their payloads and
1161 * they and their links will be garbage collected as soon as possible.
1162 */
1163void unregister_key_type(struct key_type *ktype)
1164{
1165 down_write(&key_types_sem);
1166 list_del_init(&ktype->link);
1167 downgrade_write(&key_types_sem);
1168 key_gc_keytype(ktype);
1169 pr_notice("Key type %s unregistered\n", ktype->name);
1170 up_read(&key_types_sem);
1171}
1172EXPORT_SYMBOL(unregister_key_type);
1173
1174/*
1175 * Initialise the key management state.
1176 */
1177void __init key_init(void)
1178{
1179 /* allocate a slab in which we can store keys */
1180 key_jar = kmem_cache_create("key_jar", sizeof(struct key),
1181 0, SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
1182
1183 /* add the special key types */
1184 list_add_tail(&key_type_keyring.link, &key_types_list);
1185 list_add_tail(&key_type_dead.link, &key_types_list);
1186 list_add_tail(&key_type_user.link, &key_types_list);
1187 list_add_tail(&key_type_logon.link, &key_types_list);
1188
1189 /* record the root user tracking */
1190 rb_link_node(&root_key_user.node,
1191 NULL,
1192 &key_user_tree.rb_node);
1193
1194 rb_insert_color(&root_key_user.node,
1195 &key_user_tree);
1196}