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1// SPDX-License-Identifier: GPL-2.0-or-later
2/* Request a key from userspace
3 *
4 * Copyright (C) 2004-2007 Red Hat, Inc. All Rights Reserved.
5 * Written by David Howells (dhowells@redhat.com)
6 *
7 * See Documentation/security/keys/request-key.rst
8 */
9
10#include <linux/export.h>
11#include <linux/sched.h>
12#include <linux/kmod.h>
13#include <linux/err.h>
14#include <linux/keyctl.h>
15#include <linux/slab.h>
16#include <net/net_namespace.h>
17#include "internal.h"
18#include <keys/request_key_auth-type.h>
19
20#define key_negative_timeout 60 /* default timeout on a negative key's existence */
21
22static struct key *check_cached_key(struct keyring_search_context *ctx)
23{
24#ifdef CONFIG_KEYS_REQUEST_CACHE
25 struct key *key = current->cached_requested_key;
26
27 if (key &&
28 ctx->match_data.cmp(key, &ctx->match_data) &&
29 !(key->flags & ((1 << KEY_FLAG_INVALIDATED) |
30 (1 << KEY_FLAG_REVOKED))))
31 return key_get(key);
32#endif
33 return NULL;
34}
35
36static void cache_requested_key(struct key *key)
37{
38#ifdef CONFIG_KEYS_REQUEST_CACHE
39 struct task_struct *t = current;
40
41 key_put(t->cached_requested_key);
42 t->cached_requested_key = key_get(key);
43 set_tsk_thread_flag(t, TIF_NOTIFY_RESUME);
44#endif
45}
46
47/**
48 * complete_request_key - Complete the construction of a key.
49 * @authkey: The authorisation key.
50 * @error: The success or failute of the construction.
51 *
52 * Complete the attempt to construct a key. The key will be negated
53 * if an error is indicated. The authorisation key will be revoked
54 * unconditionally.
55 */
56void complete_request_key(struct key *authkey, int error)
57{
58 struct request_key_auth *rka = get_request_key_auth(authkey);
59 struct key *key = rka->target_key;
60
61 kenter("%d{%d},%d", authkey->serial, key->serial, error);
62
63 if (error < 0)
64 key_negate_and_link(key, key_negative_timeout, NULL, authkey);
65 else
66 key_revoke(authkey);
67}
68EXPORT_SYMBOL(complete_request_key);
69
70/*
71 * Initialise a usermode helper that is going to have a specific session
72 * keyring.
73 *
74 * This is called in context of freshly forked kthread before kernel_execve(),
75 * so we can simply install the desired session_keyring at this point.
76 */
77static int umh_keys_init(struct subprocess_info *info, struct cred *cred)
78{
79 struct key *keyring = info->data;
80
81 return install_session_keyring_to_cred(cred, keyring);
82}
83
84/*
85 * Clean up a usermode helper with session keyring.
86 */
87static void umh_keys_cleanup(struct subprocess_info *info)
88{
89 struct key *keyring = info->data;
90 key_put(keyring);
91}
92
93/*
94 * Call a usermode helper with a specific session keyring.
95 */
96static int call_usermodehelper_keys(const char *path, char **argv, char **envp,
97 struct key *session_keyring, int wait)
98{
99 struct subprocess_info *info;
100
101 info = call_usermodehelper_setup(path, argv, envp, GFP_KERNEL,
102 umh_keys_init, umh_keys_cleanup,
103 session_keyring);
104 if (!info)
105 return -ENOMEM;
106
107 key_get(session_keyring);
108 return call_usermodehelper_exec(info, wait);
109}
110
111/*
112 * Request userspace finish the construction of a key
113 * - execute "/sbin/request-key <op> <key> <uid> <gid> <keyring> <keyring> <keyring>"
114 */
115static int call_sbin_request_key(struct key *authkey, void *aux)
116{
117 static char const request_key[] = "/sbin/request-key";
118 struct request_key_auth *rka = get_request_key_auth(authkey);
119 const struct cred *cred = current_cred();
120 key_serial_t prkey, sskey;
121 struct key *key = rka->target_key, *keyring, *session, *user_session;
122 char *argv[9], *envp[3], uid_str[12], gid_str[12];
123 char key_str[12], keyring_str[3][12];
124 char desc[20];
125 int ret, i;
126
127 kenter("{%d},{%d},%s", key->serial, authkey->serial, rka->op);
128
129 ret = look_up_user_keyrings(NULL, &user_session);
130 if (ret < 0)
131 goto error_us;
132
133 /* allocate a new session keyring */
134 sprintf(desc, "_req.%u", key->serial);
135
136 cred = get_current_cred();
137 keyring = keyring_alloc(desc, cred->fsuid, cred->fsgid, cred,
138 KEY_POS_ALL | KEY_USR_VIEW | KEY_USR_READ,
139 KEY_ALLOC_QUOTA_OVERRUN, NULL, NULL);
140 put_cred(cred);
141 if (IS_ERR(keyring)) {
142 ret = PTR_ERR(keyring);
143 goto error_alloc;
144 }
145
146 /* attach the auth key to the session keyring */
147 ret = key_link(keyring, authkey);
148 if (ret < 0)
149 goto error_link;
150
151 /* record the UID and GID */
152 sprintf(uid_str, "%d", from_kuid(&init_user_ns, cred->fsuid));
153 sprintf(gid_str, "%d", from_kgid(&init_user_ns, cred->fsgid));
154
155 /* we say which key is under construction */
156 sprintf(key_str, "%d", key->serial);
157
158 /* we specify the process's default keyrings */
159 sprintf(keyring_str[0], "%d",
160 cred->thread_keyring ? cred->thread_keyring->serial : 0);
161
162 prkey = 0;
163 if (cred->process_keyring)
164 prkey = cred->process_keyring->serial;
165 sprintf(keyring_str[1], "%d", prkey);
166
167 session = cred->session_keyring;
168 if (!session)
169 session = user_session;
170 sskey = session->serial;
171
172 sprintf(keyring_str[2], "%d", sskey);
173
174 /* set up a minimal environment */
175 i = 0;
176 envp[i++] = "HOME=/";
177 envp[i++] = "PATH=/sbin:/bin:/usr/sbin:/usr/bin";
178 envp[i] = NULL;
179
180 /* set up the argument list */
181 i = 0;
182 argv[i++] = (char *)request_key;
183 argv[i++] = (char *)rka->op;
184 argv[i++] = key_str;
185 argv[i++] = uid_str;
186 argv[i++] = gid_str;
187 argv[i++] = keyring_str[0];
188 argv[i++] = keyring_str[1];
189 argv[i++] = keyring_str[2];
190 argv[i] = NULL;
191
192 /* do it */
193 ret = call_usermodehelper_keys(request_key, argv, envp, keyring,
194 UMH_WAIT_PROC);
195 kdebug("usermode -> 0x%x", ret);
196 if (ret >= 0) {
197 /* ret is the exit/wait code */
198 if (test_bit(KEY_FLAG_USER_CONSTRUCT, &key->flags) ||
199 key_validate(key) < 0)
200 ret = -ENOKEY;
201 else
202 /* ignore any errors from userspace if the key was
203 * instantiated */
204 ret = 0;
205 }
206
207error_link:
208 key_put(keyring);
209
210error_alloc:
211 key_put(user_session);
212error_us:
213 complete_request_key(authkey, ret);
214 kleave(" = %d", ret);
215 return ret;
216}
217
218/*
219 * Call out to userspace for key construction.
220 *
221 * Program failure is ignored in favour of key status.
222 */
223static int construct_key(struct key *key, const void *callout_info,
224 size_t callout_len, void *aux,
225 struct key *dest_keyring)
226{
227 request_key_actor_t actor;
228 struct key *authkey;
229 int ret;
230
231 kenter("%d,%p,%zu,%p", key->serial, callout_info, callout_len, aux);
232
233 /* allocate an authorisation key */
234 authkey = request_key_auth_new(key, "create", callout_info, callout_len,
235 dest_keyring);
236 if (IS_ERR(authkey))
237 return PTR_ERR(authkey);
238
239 /* Make the call */
240 actor = call_sbin_request_key;
241 if (key->type->request_key)
242 actor = key->type->request_key;
243
244 ret = actor(authkey, aux);
245
246 /* check that the actor called complete_request_key() prior to
247 * returning an error */
248 WARN_ON(ret < 0 &&
249 !test_bit(KEY_FLAG_INVALIDATED, &authkey->flags));
250
251 key_put(authkey);
252 kleave(" = %d", ret);
253 return ret;
254}
255
256/*
257 * Get the appropriate destination keyring for the request.
258 *
259 * The keyring selected is returned with an extra reference upon it which the
260 * caller must release.
261 */
262static int construct_get_dest_keyring(struct key **_dest_keyring)
263{
264 struct request_key_auth *rka;
265 const struct cred *cred = current_cred();
266 struct key *dest_keyring = *_dest_keyring, *authkey;
267 int ret;
268
269 kenter("%p", dest_keyring);
270
271 /* find the appropriate keyring */
272 if (dest_keyring) {
273 /* the caller supplied one */
274 key_get(dest_keyring);
275 } else {
276 bool do_perm_check = true;
277
278 /* use a default keyring; falling through the cases until we
279 * find one that we actually have */
280 switch (cred->jit_keyring) {
281 case KEY_REQKEY_DEFL_DEFAULT:
282 case KEY_REQKEY_DEFL_REQUESTOR_KEYRING:
283 if (cred->request_key_auth) {
284 authkey = cred->request_key_auth;
285 down_read(&authkey->sem);
286 rka = get_request_key_auth(authkey);
287 if (!test_bit(KEY_FLAG_REVOKED,
288 &authkey->flags))
289 dest_keyring =
290 key_get(rka->dest_keyring);
291 up_read(&authkey->sem);
292 if (dest_keyring) {
293 do_perm_check = false;
294 break;
295 }
296 }
297
298 fallthrough;
299 case KEY_REQKEY_DEFL_THREAD_KEYRING:
300 dest_keyring = key_get(cred->thread_keyring);
301 if (dest_keyring)
302 break;
303
304 fallthrough;
305 case KEY_REQKEY_DEFL_PROCESS_KEYRING:
306 dest_keyring = key_get(cred->process_keyring);
307 if (dest_keyring)
308 break;
309
310 fallthrough;
311 case KEY_REQKEY_DEFL_SESSION_KEYRING:
312 dest_keyring = key_get(cred->session_keyring);
313
314 if (dest_keyring)
315 break;
316
317 fallthrough;
318 case KEY_REQKEY_DEFL_USER_SESSION_KEYRING:
319 ret = look_up_user_keyrings(NULL, &dest_keyring);
320 if (ret < 0)
321 return ret;
322 break;
323
324 case KEY_REQKEY_DEFL_USER_KEYRING:
325 ret = look_up_user_keyrings(&dest_keyring, NULL);
326 if (ret < 0)
327 return ret;
328 break;
329
330 case KEY_REQKEY_DEFL_GROUP_KEYRING:
331 default:
332 BUG();
333 }
334
335 /*
336 * Require Write permission on the keyring. This is essential
337 * because the default keyring may be the session keyring, and
338 * joining a keyring only requires Search permission.
339 *
340 * However, this check is skipped for the "requestor keyring" so
341 * that /sbin/request-key can itself use request_key() to add
342 * keys to the original requestor's destination keyring.
343 */
344 if (dest_keyring && do_perm_check) {
345 ret = key_permission(make_key_ref(dest_keyring, 1),
346 KEY_NEED_WRITE);
347 if (ret) {
348 key_put(dest_keyring);
349 return ret;
350 }
351 }
352 }
353
354 *_dest_keyring = dest_keyring;
355 kleave(" [dk %d]", key_serial(dest_keyring));
356 return 0;
357}
358
359/*
360 * Allocate a new key in under-construction state and attempt to link it in to
361 * the requested keyring.
362 *
363 * May return a key that's already under construction instead if there was a
364 * race between two thread calling request_key().
365 */
366static int construct_alloc_key(struct keyring_search_context *ctx,
367 struct key *dest_keyring,
368 unsigned long flags,
369 struct key_user *user,
370 struct key **_key)
371{
372 struct assoc_array_edit *edit = NULL;
373 struct key *key;
374 key_perm_t perm;
375 key_ref_t key_ref;
376 int ret;
377
378 kenter("%s,%s,,,",
379 ctx->index_key.type->name, ctx->index_key.description);
380
381 *_key = NULL;
382 mutex_lock(&user->cons_lock);
383
384 perm = KEY_POS_VIEW | KEY_POS_SEARCH | KEY_POS_LINK | KEY_POS_SETATTR;
385 perm |= KEY_USR_VIEW;
386 if (ctx->index_key.type->read)
387 perm |= KEY_POS_READ;
388 if (ctx->index_key.type == &key_type_keyring ||
389 ctx->index_key.type->update)
390 perm |= KEY_POS_WRITE;
391
392 key = key_alloc(ctx->index_key.type, ctx->index_key.description,
393 ctx->cred->fsuid, ctx->cred->fsgid, ctx->cred,
394 perm, flags, NULL);
395 if (IS_ERR(key))
396 goto alloc_failed;
397
398 set_bit(KEY_FLAG_USER_CONSTRUCT, &key->flags);
399
400 if (dest_keyring) {
401 ret = __key_link_lock(dest_keyring, &ctx->index_key);
402 if (ret < 0)
403 goto link_lock_failed;
404 ret = __key_link_begin(dest_keyring, &ctx->index_key, &edit);
405 if (ret < 0)
406 goto link_prealloc_failed;
407 }
408
409 /* attach the key to the destination keyring under lock, but we do need
410 * to do another check just in case someone beat us to it whilst we
411 * waited for locks */
412 mutex_lock(&key_construction_mutex);
413
414 rcu_read_lock();
415 key_ref = search_process_keyrings_rcu(ctx);
416 rcu_read_unlock();
417 if (!IS_ERR(key_ref))
418 goto key_already_present;
419
420 if (dest_keyring)
421 __key_link(dest_keyring, key, &edit);
422
423 mutex_unlock(&key_construction_mutex);
424 if (dest_keyring)
425 __key_link_end(dest_keyring, &ctx->index_key, edit);
426 mutex_unlock(&user->cons_lock);
427 *_key = key;
428 kleave(" = 0 [%d]", key_serial(key));
429 return 0;
430
431 /* the key is now present - we tell the caller that we found it by
432 * returning -EINPROGRESS */
433key_already_present:
434 key_put(key);
435 mutex_unlock(&key_construction_mutex);
436 key = key_ref_to_ptr(key_ref);
437 if (dest_keyring) {
438 ret = __key_link_check_live_key(dest_keyring, key);
439 if (ret == 0)
440 __key_link(dest_keyring, key, &edit);
441 __key_link_end(dest_keyring, &ctx->index_key, edit);
442 if (ret < 0)
443 goto link_check_failed;
444 }
445 mutex_unlock(&user->cons_lock);
446 *_key = key;
447 kleave(" = -EINPROGRESS [%d]", key_serial(key));
448 return -EINPROGRESS;
449
450link_check_failed:
451 mutex_unlock(&user->cons_lock);
452 key_put(key);
453 kleave(" = %d [linkcheck]", ret);
454 return ret;
455
456link_prealloc_failed:
457 __key_link_end(dest_keyring, &ctx->index_key, edit);
458link_lock_failed:
459 mutex_unlock(&user->cons_lock);
460 key_put(key);
461 kleave(" = %d [prelink]", ret);
462 return ret;
463
464alloc_failed:
465 mutex_unlock(&user->cons_lock);
466 kleave(" = %ld", PTR_ERR(key));
467 return PTR_ERR(key);
468}
469
470/*
471 * Commence key construction.
472 */
473static struct key *construct_key_and_link(struct keyring_search_context *ctx,
474 const char *callout_info,
475 size_t callout_len,
476 void *aux,
477 struct key *dest_keyring,
478 unsigned long flags)
479{
480 struct key_user *user;
481 struct key *key;
482 int ret;
483
484 kenter("");
485
486 if (ctx->index_key.type == &key_type_keyring)
487 return ERR_PTR(-EPERM);
488
489 ret = construct_get_dest_keyring(&dest_keyring);
490 if (ret)
491 goto error;
492
493 user = key_user_lookup(current_fsuid());
494 if (!user) {
495 ret = -ENOMEM;
496 goto error_put_dest_keyring;
497 }
498
499 ret = construct_alloc_key(ctx, dest_keyring, flags, user, &key);
500 key_user_put(user);
501
502 if (ret == 0) {
503 ret = construct_key(key, callout_info, callout_len, aux,
504 dest_keyring);
505 if (ret < 0) {
506 kdebug("cons failed");
507 goto construction_failed;
508 }
509 } else if (ret == -EINPROGRESS) {
510 ret = 0;
511 } else {
512 goto error_put_dest_keyring;
513 }
514
515 key_put(dest_keyring);
516 kleave(" = key %d", key_serial(key));
517 return key;
518
519construction_failed:
520 key_negate_and_link(key, key_negative_timeout, NULL, NULL);
521 key_put(key);
522error_put_dest_keyring:
523 key_put(dest_keyring);
524error:
525 kleave(" = %d", ret);
526 return ERR_PTR(ret);
527}
528
529/**
530 * request_key_and_link - Request a key and cache it in a keyring.
531 * @type: The type of key we want.
532 * @description: The searchable description of the key.
533 * @domain_tag: The domain in which the key operates.
534 * @callout_info: The data to pass to the instantiation upcall (or NULL).
535 * @callout_len: The length of callout_info.
536 * @aux: Auxiliary data for the upcall.
537 * @dest_keyring: Where to cache the key.
538 * @flags: Flags to key_alloc().
539 *
540 * A key matching the specified criteria (type, description, domain_tag) is
541 * searched for in the process's keyrings and returned with its usage count
542 * incremented if found. Otherwise, if callout_info is not NULL, a key will be
543 * allocated and some service (probably in userspace) will be asked to
544 * instantiate it.
545 *
546 * If successfully found or created, the key will be linked to the destination
547 * keyring if one is provided.
548 *
549 * Returns a pointer to the key if successful; -EACCES, -ENOKEY, -EKEYREVOKED
550 * or -EKEYEXPIRED if an inaccessible, negative, revoked or expired key was
551 * found; -ENOKEY if no key was found and no @callout_info was given; -EDQUOT
552 * if insufficient key quota was available to create a new key; or -ENOMEM if
553 * insufficient memory was available.
554 *
555 * If the returned key was created, then it may still be under construction,
556 * and wait_for_key_construction() should be used to wait for that to complete.
557 */
558struct key *request_key_and_link(struct key_type *type,
559 const char *description,
560 struct key_tag *domain_tag,
561 const void *callout_info,
562 size_t callout_len,
563 void *aux,
564 struct key *dest_keyring,
565 unsigned long flags)
566{
567 struct keyring_search_context ctx = {
568 .index_key.type = type,
569 .index_key.domain_tag = domain_tag,
570 .index_key.description = description,
571 .index_key.desc_len = strlen(description),
572 .cred = current_cred(),
573 .match_data.cmp = key_default_cmp,
574 .match_data.raw_data = description,
575 .match_data.lookup_type = KEYRING_SEARCH_LOOKUP_DIRECT,
576 .flags = (KEYRING_SEARCH_DO_STATE_CHECK |
577 KEYRING_SEARCH_SKIP_EXPIRED |
578 KEYRING_SEARCH_RECURSE),
579 };
580 struct key *key;
581 key_ref_t key_ref;
582 int ret;
583
584 kenter("%s,%s,%p,%zu,%p,%p,%lx",
585 ctx.index_key.type->name, ctx.index_key.description,
586 callout_info, callout_len, aux, dest_keyring, flags);
587
588 if (type->match_preparse) {
589 ret = type->match_preparse(&ctx.match_data);
590 if (ret < 0) {
591 key = ERR_PTR(ret);
592 goto error;
593 }
594 }
595
596 key = check_cached_key(&ctx);
597 if (key)
598 goto error_free;
599
600 /* search all the process keyrings for a key */
601 rcu_read_lock();
602 key_ref = search_process_keyrings_rcu(&ctx);
603 rcu_read_unlock();
604
605 if (!IS_ERR(key_ref)) {
606 if (dest_keyring) {
607 ret = key_task_permission(key_ref, current_cred(),
608 KEY_NEED_LINK);
609 if (ret < 0) {
610 key_ref_put(key_ref);
611 key = ERR_PTR(ret);
612 goto error_free;
613 }
614 }
615
616 key = key_ref_to_ptr(key_ref);
617 if (dest_keyring) {
618 ret = key_link(dest_keyring, key);
619 if (ret < 0) {
620 key_put(key);
621 key = ERR_PTR(ret);
622 goto error_free;
623 }
624 }
625
626 /* Only cache the key on immediate success */
627 cache_requested_key(key);
628 } else if (PTR_ERR(key_ref) != -EAGAIN) {
629 key = ERR_CAST(key_ref);
630 } else {
631 /* the search failed, but the keyrings were searchable, so we
632 * should consult userspace if we can */
633 key = ERR_PTR(-ENOKEY);
634 if (!callout_info)
635 goto error_free;
636
637 key = construct_key_and_link(&ctx, callout_info, callout_len,
638 aux, dest_keyring, flags);
639 }
640
641error_free:
642 if (type->match_free)
643 type->match_free(&ctx.match_data);
644error:
645 kleave(" = %p", key);
646 return key;
647}
648
649/**
650 * wait_for_key_construction - Wait for construction of a key to complete
651 * @key: The key being waited for.
652 * @intr: Whether to wait interruptibly.
653 *
654 * Wait for a key to finish being constructed.
655 *
656 * Returns 0 if successful; -ERESTARTSYS if the wait was interrupted; -ENOKEY
657 * if the key was negated; or -EKEYREVOKED or -EKEYEXPIRED if the key was
658 * revoked or expired.
659 */
660int wait_for_key_construction(struct key *key, bool intr)
661{
662 int ret;
663
664 ret = wait_on_bit(&key->flags, KEY_FLAG_USER_CONSTRUCT,
665 intr ? TASK_INTERRUPTIBLE : TASK_UNINTERRUPTIBLE);
666 if (ret)
667 return -ERESTARTSYS;
668 ret = key_read_state(key);
669 if (ret < 0)
670 return ret;
671 return key_validate(key);
672}
673EXPORT_SYMBOL(wait_for_key_construction);
674
675/**
676 * request_key_tag - Request a key and wait for construction
677 * @type: Type of key.
678 * @description: The searchable description of the key.
679 * @domain_tag: The domain in which the key operates.
680 * @callout_info: The data to pass to the instantiation upcall (or NULL).
681 *
682 * As for request_key_and_link() except that it does not add the returned key
683 * to a keyring if found, new keys are always allocated in the user's quota,
684 * the callout_info must be a NUL-terminated string and no auxiliary data can
685 * be passed.
686 *
687 * Furthermore, it then works as wait_for_key_construction() to wait for the
688 * completion of keys undergoing construction with a non-interruptible wait.
689 */
690struct key *request_key_tag(struct key_type *type,
691 const char *description,
692 struct key_tag *domain_tag,
693 const char *callout_info)
694{
695 struct key *key;
696 size_t callout_len = 0;
697 int ret;
698
699 if (callout_info)
700 callout_len = strlen(callout_info);
701 key = request_key_and_link(type, description, domain_tag,
702 callout_info, callout_len,
703 NULL, NULL, KEY_ALLOC_IN_QUOTA);
704 if (!IS_ERR(key)) {
705 ret = wait_for_key_construction(key, false);
706 if (ret < 0) {
707 key_put(key);
708 return ERR_PTR(ret);
709 }
710 }
711 return key;
712}
713EXPORT_SYMBOL(request_key_tag);
714
715/**
716 * request_key_with_auxdata - Request a key with auxiliary data for the upcaller
717 * @type: The type of key we want.
718 * @description: The searchable description of the key.
719 * @domain_tag: The domain in which the key operates.
720 * @callout_info: The data to pass to the instantiation upcall (or NULL).
721 * @callout_len: The length of callout_info.
722 * @aux: Auxiliary data for the upcall.
723 *
724 * As for request_key_and_link() except that it does not add the returned key
725 * to a keyring if found and new keys are always allocated in the user's quota.
726 *
727 * Furthermore, it then works as wait_for_key_construction() to wait for the
728 * completion of keys undergoing construction with a non-interruptible wait.
729 */
730struct key *request_key_with_auxdata(struct key_type *type,
731 const char *description,
732 struct key_tag *domain_tag,
733 const void *callout_info,
734 size_t callout_len,
735 void *aux)
736{
737 struct key *key;
738 int ret;
739
740 key = request_key_and_link(type, description, domain_tag,
741 callout_info, callout_len,
742 aux, NULL, KEY_ALLOC_IN_QUOTA);
743 if (!IS_ERR(key)) {
744 ret = wait_for_key_construction(key, false);
745 if (ret < 0) {
746 key_put(key);
747 return ERR_PTR(ret);
748 }
749 }
750 return key;
751}
752EXPORT_SYMBOL(request_key_with_auxdata);
753
754/**
755 * request_key_rcu - Request key from RCU-read-locked context
756 * @type: The type of key we want.
757 * @description: The name of the key we want.
758 * @domain_tag: The domain in which the key operates.
759 *
760 * Request a key from a context that we may not sleep in (such as RCU-mode
761 * pathwalk). Keys under construction are ignored.
762 *
763 * Return a pointer to the found key if successful, -ENOKEY if we couldn't find
764 * a key or some other error if the key found was unsuitable or inaccessible.
765 */
766struct key *request_key_rcu(struct key_type *type,
767 const char *description,
768 struct key_tag *domain_tag)
769{
770 struct keyring_search_context ctx = {
771 .index_key.type = type,
772 .index_key.domain_tag = domain_tag,
773 .index_key.description = description,
774 .index_key.desc_len = strlen(description),
775 .cred = current_cred(),
776 .match_data.cmp = key_default_cmp,
777 .match_data.raw_data = description,
778 .match_data.lookup_type = KEYRING_SEARCH_LOOKUP_DIRECT,
779 .flags = (KEYRING_SEARCH_DO_STATE_CHECK |
780 KEYRING_SEARCH_SKIP_EXPIRED),
781 };
782 struct key *key;
783 key_ref_t key_ref;
784
785 kenter("%s,%s", type->name, description);
786
787 key = check_cached_key(&ctx);
788 if (key)
789 return key;
790
791 /* search all the process keyrings for a key */
792 key_ref = search_process_keyrings_rcu(&ctx);
793 if (IS_ERR(key_ref)) {
794 key = ERR_CAST(key_ref);
795 if (PTR_ERR(key_ref) == -EAGAIN)
796 key = ERR_PTR(-ENOKEY);
797 } else {
798 key = key_ref_to_ptr(key_ref);
799 cache_requested_key(key);
800 }
801
802 kleave(" = %p", key);
803 return key;
804}
805EXPORT_SYMBOL(request_key_rcu);
1/* Request a key from userspace
2 *
3 * Copyright (C) 2004-2007 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 * See Documentation/security/keys-request-key.txt
12 */
13
14#include <linux/module.h>
15#include <linux/sched.h>
16#include <linux/kmod.h>
17#include <linux/err.h>
18#include <linux/keyctl.h>
19#include <linux/slab.h>
20#include "internal.h"
21
22#define key_negative_timeout 60 /* default timeout on a negative key's existence */
23
24/*
25 * wait_on_bit() sleep function for uninterruptible waiting
26 */
27static int key_wait_bit(void *flags)
28{
29 schedule();
30 return 0;
31}
32
33/*
34 * wait_on_bit() sleep function for interruptible waiting
35 */
36static int key_wait_bit_intr(void *flags)
37{
38 schedule();
39 return signal_pending(current) ? -ERESTARTSYS : 0;
40}
41
42/**
43 * complete_request_key - Complete the construction of a key.
44 * @cons: The key construction record.
45 * @error: The success or failute of the construction.
46 *
47 * Complete the attempt to construct a key. The key will be negated
48 * if an error is indicated. The authorisation key will be revoked
49 * unconditionally.
50 */
51void complete_request_key(struct key_construction *cons, int error)
52{
53 kenter("{%d,%d},%d", cons->key->serial, cons->authkey->serial, error);
54
55 if (error < 0)
56 key_negate_and_link(cons->key, key_negative_timeout, NULL,
57 cons->authkey);
58 else
59 key_revoke(cons->authkey);
60
61 key_put(cons->key);
62 key_put(cons->authkey);
63 kfree(cons);
64}
65EXPORT_SYMBOL(complete_request_key);
66
67/*
68 * Initialise a usermode helper that is going to have a specific session
69 * keyring.
70 *
71 * This is called in context of freshly forked kthread before kernel_execve(),
72 * so we can simply install the desired session_keyring at this point.
73 */
74static int umh_keys_init(struct subprocess_info *info, struct cred *cred)
75{
76 struct key *keyring = info->data;
77
78 return install_session_keyring_to_cred(cred, keyring);
79}
80
81/*
82 * Clean up a usermode helper with session keyring.
83 */
84static void umh_keys_cleanup(struct subprocess_info *info)
85{
86 struct key *keyring = info->data;
87 key_put(keyring);
88}
89
90/*
91 * Call a usermode helper with a specific session keyring.
92 */
93static int call_usermodehelper_keys(char *path, char **argv, char **envp,
94 struct key *session_keyring, int wait)
95{
96 struct subprocess_info *info;
97
98 info = call_usermodehelper_setup(path, argv, envp, GFP_KERNEL,
99 umh_keys_init, umh_keys_cleanup,
100 session_keyring);
101 if (!info)
102 return -ENOMEM;
103
104 key_get(session_keyring);
105 return call_usermodehelper_exec(info, wait);
106}
107
108/*
109 * Request userspace finish the construction of a key
110 * - execute "/sbin/request-key <op> <key> <uid> <gid> <keyring> <keyring> <keyring>"
111 */
112static int call_sbin_request_key(struct key_construction *cons,
113 const char *op,
114 void *aux)
115{
116 const struct cred *cred = current_cred();
117 key_serial_t prkey, sskey;
118 struct key *key = cons->key, *authkey = cons->authkey, *keyring,
119 *session;
120 char *argv[9], *envp[3], uid_str[12], gid_str[12];
121 char key_str[12], keyring_str[3][12];
122 char desc[20];
123 int ret, i;
124
125 kenter("{%d},{%d},%s", key->serial, authkey->serial, op);
126
127 ret = install_user_keyrings();
128 if (ret < 0)
129 goto error_alloc;
130
131 /* allocate a new session keyring */
132 sprintf(desc, "_req.%u", key->serial);
133
134 cred = get_current_cred();
135 keyring = keyring_alloc(desc, cred->fsuid, cred->fsgid, cred,
136 KEY_POS_ALL | KEY_USR_VIEW | KEY_USR_READ,
137 KEY_ALLOC_QUOTA_OVERRUN, NULL);
138 put_cred(cred);
139 if (IS_ERR(keyring)) {
140 ret = PTR_ERR(keyring);
141 goto error_alloc;
142 }
143
144 /* attach the auth key to the session keyring */
145 ret = key_link(keyring, authkey);
146 if (ret < 0)
147 goto error_link;
148
149 /* record the UID and GID */
150 sprintf(uid_str, "%d", from_kuid(&init_user_ns, cred->fsuid));
151 sprintf(gid_str, "%d", from_kgid(&init_user_ns, cred->fsgid));
152
153 /* we say which key is under construction */
154 sprintf(key_str, "%d", key->serial);
155
156 /* we specify the process's default keyrings */
157 sprintf(keyring_str[0], "%d",
158 cred->thread_keyring ? cred->thread_keyring->serial : 0);
159
160 prkey = 0;
161 if (cred->process_keyring)
162 prkey = cred->process_keyring->serial;
163 sprintf(keyring_str[1], "%d", prkey);
164
165 rcu_read_lock();
166 session = rcu_dereference(cred->session_keyring);
167 if (!session)
168 session = cred->user->session_keyring;
169 sskey = session->serial;
170 rcu_read_unlock();
171
172 sprintf(keyring_str[2], "%d", sskey);
173
174 /* set up a minimal environment */
175 i = 0;
176 envp[i++] = "HOME=/";
177 envp[i++] = "PATH=/sbin:/bin:/usr/sbin:/usr/bin";
178 envp[i] = NULL;
179
180 /* set up the argument list */
181 i = 0;
182 argv[i++] = "/sbin/request-key";
183 argv[i++] = (char *) op;
184 argv[i++] = key_str;
185 argv[i++] = uid_str;
186 argv[i++] = gid_str;
187 argv[i++] = keyring_str[0];
188 argv[i++] = keyring_str[1];
189 argv[i++] = keyring_str[2];
190 argv[i] = NULL;
191
192 /* do it */
193 ret = call_usermodehelper_keys(argv[0], argv, envp, keyring,
194 UMH_WAIT_PROC);
195 kdebug("usermode -> 0x%x", ret);
196 if (ret >= 0) {
197 /* ret is the exit/wait code */
198 if (test_bit(KEY_FLAG_USER_CONSTRUCT, &key->flags) ||
199 key_validate(key) < 0)
200 ret = -ENOKEY;
201 else
202 /* ignore any errors from userspace if the key was
203 * instantiated */
204 ret = 0;
205 }
206
207error_link:
208 key_put(keyring);
209
210error_alloc:
211 complete_request_key(cons, ret);
212 kleave(" = %d", ret);
213 return ret;
214}
215
216/*
217 * Call out to userspace for key construction.
218 *
219 * Program failure is ignored in favour of key status.
220 */
221static int construct_key(struct key *key, const void *callout_info,
222 size_t callout_len, void *aux,
223 struct key *dest_keyring)
224{
225 struct key_construction *cons;
226 request_key_actor_t actor;
227 struct key *authkey;
228 int ret;
229
230 kenter("%d,%p,%zu,%p", key->serial, callout_info, callout_len, aux);
231
232 cons = kmalloc(sizeof(*cons), GFP_KERNEL);
233 if (!cons)
234 return -ENOMEM;
235
236 /* allocate an authorisation key */
237 authkey = request_key_auth_new(key, callout_info, callout_len,
238 dest_keyring);
239 if (IS_ERR(authkey)) {
240 kfree(cons);
241 ret = PTR_ERR(authkey);
242 authkey = NULL;
243 } else {
244 cons->authkey = key_get(authkey);
245 cons->key = key_get(key);
246
247 /* make the call */
248 actor = call_sbin_request_key;
249 if (key->type->request_key)
250 actor = key->type->request_key;
251
252 ret = actor(cons, "create", aux);
253
254 /* check that the actor called complete_request_key() prior to
255 * returning an error */
256 WARN_ON(ret < 0 &&
257 !test_bit(KEY_FLAG_REVOKED, &authkey->flags));
258 key_put(authkey);
259 }
260
261 kleave(" = %d", ret);
262 return ret;
263}
264
265/*
266 * Get the appropriate destination keyring for the request.
267 *
268 * The keyring selected is returned with an extra reference upon it which the
269 * caller must release.
270 */
271static void construct_get_dest_keyring(struct key **_dest_keyring)
272{
273 struct request_key_auth *rka;
274 const struct cred *cred = current_cred();
275 struct key *dest_keyring = *_dest_keyring, *authkey;
276
277 kenter("%p", dest_keyring);
278
279 /* find the appropriate keyring */
280 if (dest_keyring) {
281 /* the caller supplied one */
282 key_get(dest_keyring);
283 } else {
284 /* use a default keyring; falling through the cases until we
285 * find one that we actually have */
286 switch (cred->jit_keyring) {
287 case KEY_REQKEY_DEFL_DEFAULT:
288 case KEY_REQKEY_DEFL_REQUESTOR_KEYRING:
289 if (cred->request_key_auth) {
290 authkey = cred->request_key_auth;
291 down_read(&authkey->sem);
292 rka = authkey->payload.data;
293 if (!test_bit(KEY_FLAG_REVOKED,
294 &authkey->flags))
295 dest_keyring =
296 key_get(rka->dest_keyring);
297 up_read(&authkey->sem);
298 if (dest_keyring)
299 break;
300 }
301
302 case KEY_REQKEY_DEFL_THREAD_KEYRING:
303 dest_keyring = key_get(cred->thread_keyring);
304 if (dest_keyring)
305 break;
306
307 case KEY_REQKEY_DEFL_PROCESS_KEYRING:
308 dest_keyring = key_get(cred->process_keyring);
309 if (dest_keyring)
310 break;
311
312 case KEY_REQKEY_DEFL_SESSION_KEYRING:
313 rcu_read_lock();
314 dest_keyring = key_get(
315 rcu_dereference(cred->session_keyring));
316 rcu_read_unlock();
317
318 if (dest_keyring)
319 break;
320
321 case KEY_REQKEY_DEFL_USER_SESSION_KEYRING:
322 dest_keyring =
323 key_get(cred->user->session_keyring);
324 break;
325
326 case KEY_REQKEY_DEFL_USER_KEYRING:
327 dest_keyring = key_get(cred->user->uid_keyring);
328 break;
329
330 case KEY_REQKEY_DEFL_GROUP_KEYRING:
331 default:
332 BUG();
333 }
334 }
335
336 *_dest_keyring = dest_keyring;
337 kleave(" [dk %d]", key_serial(dest_keyring));
338 return;
339}
340
341/*
342 * Allocate a new key in under-construction state and attempt to link it in to
343 * the requested keyring.
344 *
345 * May return a key that's already under construction instead if there was a
346 * race between two thread calling request_key().
347 */
348static int construct_alloc_key(struct keyring_search_context *ctx,
349 struct key *dest_keyring,
350 unsigned long flags,
351 struct key_user *user,
352 struct key **_key)
353{
354 struct assoc_array_edit *edit;
355 struct key *key;
356 key_perm_t perm;
357 key_ref_t key_ref;
358 int ret;
359
360 kenter("%s,%s,,,",
361 ctx->index_key.type->name, ctx->index_key.description);
362
363 *_key = NULL;
364 mutex_lock(&user->cons_lock);
365
366 perm = KEY_POS_VIEW | KEY_POS_SEARCH | KEY_POS_LINK | KEY_POS_SETATTR;
367 perm |= KEY_USR_VIEW;
368 if (ctx->index_key.type->read)
369 perm |= KEY_POS_READ;
370 if (ctx->index_key.type == &key_type_keyring ||
371 ctx->index_key.type->update)
372 perm |= KEY_POS_WRITE;
373
374 key = key_alloc(ctx->index_key.type, ctx->index_key.description,
375 ctx->cred->fsuid, ctx->cred->fsgid, ctx->cred,
376 perm, flags);
377 if (IS_ERR(key))
378 goto alloc_failed;
379
380 set_bit(KEY_FLAG_USER_CONSTRUCT, &key->flags);
381
382 if (dest_keyring) {
383 ret = __key_link_begin(dest_keyring, &ctx->index_key, &edit);
384 if (ret < 0)
385 goto link_prealloc_failed;
386 }
387
388 /* attach the key to the destination keyring under lock, but we do need
389 * to do another check just in case someone beat us to it whilst we
390 * waited for locks */
391 mutex_lock(&key_construction_mutex);
392
393 key_ref = search_process_keyrings(ctx);
394 if (!IS_ERR(key_ref))
395 goto key_already_present;
396
397 if (dest_keyring)
398 __key_link(key, &edit);
399
400 mutex_unlock(&key_construction_mutex);
401 if (dest_keyring)
402 __key_link_end(dest_keyring, &ctx->index_key, edit);
403 mutex_unlock(&user->cons_lock);
404 *_key = key;
405 kleave(" = 0 [%d]", key_serial(key));
406 return 0;
407
408 /* the key is now present - we tell the caller that we found it by
409 * returning -EINPROGRESS */
410key_already_present:
411 key_put(key);
412 mutex_unlock(&key_construction_mutex);
413 key = key_ref_to_ptr(key_ref);
414 if (dest_keyring) {
415 ret = __key_link_check_live_key(dest_keyring, key);
416 if (ret == 0)
417 __key_link(key, &edit);
418 __key_link_end(dest_keyring, &ctx->index_key, edit);
419 if (ret < 0)
420 goto link_check_failed;
421 }
422 mutex_unlock(&user->cons_lock);
423 *_key = key;
424 kleave(" = -EINPROGRESS [%d]", key_serial(key));
425 return -EINPROGRESS;
426
427link_check_failed:
428 mutex_unlock(&user->cons_lock);
429 key_put(key);
430 kleave(" = %d [linkcheck]", ret);
431 return ret;
432
433link_prealloc_failed:
434 mutex_unlock(&user->cons_lock);
435 kleave(" = %d [prelink]", ret);
436 return ret;
437
438alloc_failed:
439 mutex_unlock(&user->cons_lock);
440 kleave(" = %ld", PTR_ERR(key));
441 return PTR_ERR(key);
442}
443
444/*
445 * Commence key construction.
446 */
447static struct key *construct_key_and_link(struct keyring_search_context *ctx,
448 const char *callout_info,
449 size_t callout_len,
450 void *aux,
451 struct key *dest_keyring,
452 unsigned long flags)
453{
454 struct key_user *user;
455 struct key *key;
456 int ret;
457
458 kenter("");
459
460 user = key_user_lookup(current_fsuid());
461 if (!user)
462 return ERR_PTR(-ENOMEM);
463
464 construct_get_dest_keyring(&dest_keyring);
465
466 ret = construct_alloc_key(ctx, dest_keyring, flags, user, &key);
467 key_user_put(user);
468
469 if (ret == 0) {
470 ret = construct_key(key, callout_info, callout_len, aux,
471 dest_keyring);
472 if (ret < 0) {
473 kdebug("cons failed");
474 goto construction_failed;
475 }
476 } else if (ret == -EINPROGRESS) {
477 ret = 0;
478 } else {
479 goto couldnt_alloc_key;
480 }
481
482 key_put(dest_keyring);
483 kleave(" = key %d", key_serial(key));
484 return key;
485
486construction_failed:
487 key_negate_and_link(key, key_negative_timeout, NULL, NULL);
488 key_put(key);
489couldnt_alloc_key:
490 key_put(dest_keyring);
491 kleave(" = %d", ret);
492 return ERR_PTR(ret);
493}
494
495/**
496 * request_key_and_link - Request a key and cache it in a keyring.
497 * @type: The type of key we want.
498 * @description: The searchable description of the key.
499 * @callout_info: The data to pass to the instantiation upcall (or NULL).
500 * @callout_len: The length of callout_info.
501 * @aux: Auxiliary data for the upcall.
502 * @dest_keyring: Where to cache the key.
503 * @flags: Flags to key_alloc().
504 *
505 * A key matching the specified criteria is searched for in the process's
506 * keyrings and returned with its usage count incremented if found. Otherwise,
507 * if callout_info is not NULL, a key will be allocated and some service
508 * (probably in userspace) will be asked to instantiate it.
509 *
510 * If successfully found or created, the key will be linked to the destination
511 * keyring if one is provided.
512 *
513 * Returns a pointer to the key if successful; -EACCES, -ENOKEY, -EKEYREVOKED
514 * or -EKEYEXPIRED if an inaccessible, negative, revoked or expired key was
515 * found; -ENOKEY if no key was found and no @callout_info was given; -EDQUOT
516 * if insufficient key quota was available to create a new key; or -ENOMEM if
517 * insufficient memory was available.
518 *
519 * If the returned key was created, then it may still be under construction,
520 * and wait_for_key_construction() should be used to wait for that to complete.
521 */
522struct key *request_key_and_link(struct key_type *type,
523 const char *description,
524 const void *callout_info,
525 size_t callout_len,
526 void *aux,
527 struct key *dest_keyring,
528 unsigned long flags)
529{
530 struct keyring_search_context ctx = {
531 .index_key.type = type,
532 .index_key.description = description,
533 .cred = current_cred(),
534 .match = type->match,
535 .match_data = description,
536 .flags = KEYRING_SEARCH_LOOKUP_DIRECT,
537 };
538 struct key *key;
539 key_ref_t key_ref;
540 int ret;
541
542 kenter("%s,%s,%p,%zu,%p,%p,%lx",
543 ctx.index_key.type->name, ctx.index_key.description,
544 callout_info, callout_len, aux, dest_keyring, flags);
545
546 /* search all the process keyrings for a key */
547 key_ref = search_process_keyrings(&ctx);
548
549 if (!IS_ERR(key_ref)) {
550 key = key_ref_to_ptr(key_ref);
551 if (dest_keyring) {
552 construct_get_dest_keyring(&dest_keyring);
553 ret = key_link(dest_keyring, key);
554 key_put(dest_keyring);
555 if (ret < 0) {
556 key_put(key);
557 key = ERR_PTR(ret);
558 goto error;
559 }
560 }
561 } else if (PTR_ERR(key_ref) != -EAGAIN) {
562 key = ERR_CAST(key_ref);
563 } else {
564 /* the search failed, but the keyrings were searchable, so we
565 * should consult userspace if we can */
566 key = ERR_PTR(-ENOKEY);
567 if (!callout_info)
568 goto error;
569
570 key = construct_key_and_link(&ctx, callout_info, callout_len,
571 aux, dest_keyring, flags);
572 }
573
574error:
575 kleave(" = %p", key);
576 return key;
577}
578
579/**
580 * wait_for_key_construction - Wait for construction of a key to complete
581 * @key: The key being waited for.
582 * @intr: Whether to wait interruptibly.
583 *
584 * Wait for a key to finish being constructed.
585 *
586 * Returns 0 if successful; -ERESTARTSYS if the wait was interrupted; -ENOKEY
587 * if the key was negated; or -EKEYREVOKED or -EKEYEXPIRED if the key was
588 * revoked or expired.
589 */
590int wait_for_key_construction(struct key *key, bool intr)
591{
592 int ret;
593
594 ret = wait_on_bit(&key->flags, KEY_FLAG_USER_CONSTRUCT,
595 intr ? key_wait_bit_intr : key_wait_bit,
596 intr ? TASK_INTERRUPTIBLE : TASK_UNINTERRUPTIBLE);
597 if (ret < 0)
598 return ret;
599 if (test_bit(KEY_FLAG_NEGATIVE, &key->flags)) {
600 smp_rmb();
601 return key->type_data.reject_error;
602 }
603 return key_validate(key);
604}
605EXPORT_SYMBOL(wait_for_key_construction);
606
607/**
608 * request_key - Request a key and wait for construction
609 * @type: Type of key.
610 * @description: The searchable description of the key.
611 * @callout_info: The data to pass to the instantiation upcall (or NULL).
612 *
613 * As for request_key_and_link() except that it does not add the returned key
614 * to a keyring if found, new keys are always allocated in the user's quota,
615 * the callout_info must be a NUL-terminated string and no auxiliary data can
616 * be passed.
617 *
618 * Furthermore, it then works as wait_for_key_construction() to wait for the
619 * completion of keys undergoing construction with a non-interruptible wait.
620 */
621struct key *request_key(struct key_type *type,
622 const char *description,
623 const char *callout_info)
624{
625 struct key *key;
626 size_t callout_len = 0;
627 int ret;
628
629 if (callout_info)
630 callout_len = strlen(callout_info);
631 key = request_key_and_link(type, description, callout_info, callout_len,
632 NULL, NULL, KEY_ALLOC_IN_QUOTA);
633 if (!IS_ERR(key)) {
634 ret = wait_for_key_construction(key, false);
635 if (ret < 0) {
636 key_put(key);
637 return ERR_PTR(ret);
638 }
639 }
640 return key;
641}
642EXPORT_SYMBOL(request_key);
643
644/**
645 * request_key_with_auxdata - Request a key with auxiliary data for the upcaller
646 * @type: The type of key we want.
647 * @description: The searchable description of the key.
648 * @callout_info: The data to pass to the instantiation upcall (or NULL).
649 * @callout_len: The length of callout_info.
650 * @aux: Auxiliary data for the upcall.
651 *
652 * As for request_key_and_link() except that it does not add the returned key
653 * to a keyring if found and new keys are always allocated in the user's quota.
654 *
655 * Furthermore, it then works as wait_for_key_construction() to wait for the
656 * completion of keys undergoing construction with a non-interruptible wait.
657 */
658struct key *request_key_with_auxdata(struct key_type *type,
659 const char *description,
660 const void *callout_info,
661 size_t callout_len,
662 void *aux)
663{
664 struct key *key;
665 int ret;
666
667 key = request_key_and_link(type, description, callout_info, callout_len,
668 aux, NULL, KEY_ALLOC_IN_QUOTA);
669 if (!IS_ERR(key)) {
670 ret = wait_for_key_construction(key, false);
671 if (ret < 0) {
672 key_put(key);
673 return ERR_PTR(ret);
674 }
675 }
676 return key;
677}
678EXPORT_SYMBOL(request_key_with_auxdata);
679
680/*
681 * request_key_async - Request a key (allow async construction)
682 * @type: Type of key.
683 * @description: The searchable description of the key.
684 * @callout_info: The data to pass to the instantiation upcall (or NULL).
685 * @callout_len: The length of callout_info.
686 *
687 * As for request_key_and_link() except that it does not add the returned key
688 * to a keyring if found, new keys are always allocated in the user's quota and
689 * no auxiliary data can be passed.
690 *
691 * The caller should call wait_for_key_construction() to wait for the
692 * completion of the returned key if it is still undergoing construction.
693 */
694struct key *request_key_async(struct key_type *type,
695 const char *description,
696 const void *callout_info,
697 size_t callout_len)
698{
699 return request_key_and_link(type, description, callout_info,
700 callout_len, NULL, NULL,
701 KEY_ALLOC_IN_QUOTA);
702}
703EXPORT_SYMBOL(request_key_async);
704
705/*
706 * request a key with auxiliary data for the upcaller (allow async construction)
707 * @type: Type of key.
708 * @description: The searchable description of the key.
709 * @callout_info: The data to pass to the instantiation upcall (or NULL).
710 * @callout_len: The length of callout_info.
711 * @aux: Auxiliary data for the upcall.
712 *
713 * As for request_key_and_link() except that it does not add the returned key
714 * to a keyring if found and new keys are always allocated in the user's quota.
715 *
716 * The caller should call wait_for_key_construction() to wait for the
717 * completion of the returned key if it is still undergoing construction.
718 */
719struct key *request_key_async_with_auxdata(struct key_type *type,
720 const char *description,
721 const void *callout_info,
722 size_t callout_len,
723 void *aux)
724{
725 return request_key_and_link(type, description, callout_info,
726 callout_len, aux, NULL, KEY_ALLOC_IN_QUOTA);
727}
728EXPORT_SYMBOL(request_key_async_with_auxdata);