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1/* Userspace key control operations
2 *
3 * Copyright (C) 2004-5 Red Hat, Inc. All Rights Reserved.
4 * Written by David Howells (dhowells@redhat.com)
5 *
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public License
8 * as published by the Free Software Foundation; either version
9 * 2 of the License, or (at your option) any later version.
10 */
11
12#include <linux/module.h>
13#include <linux/init.h>
14#include <linux/sched.h>
15#include <linux/slab.h>
16#include <linux/syscalls.h>
17#include <linux/keyctl.h>
18#include <linux/fs.h>
19#include <linux/capability.h>
20#include <linux/string.h>
21#include <linux/err.h>
22#include <linux/vmalloc.h>
23#include <linux/security.h>
24#include <asm/uaccess.h>
25#include "internal.h"
26
27static int key_get_type_from_user(char *type,
28 const char __user *_type,
29 unsigned len)
30{
31 int ret;
32
33 ret = strncpy_from_user(type, _type, len);
34 if (ret < 0)
35 return ret;
36 if (ret == 0 || ret >= len)
37 return -EINVAL;
38 if (type[0] == '.')
39 return -EPERM;
40 type[len - 1] = '\0';
41 return 0;
42}
43
44/*
45 * Extract the description of a new key from userspace and either add it as a
46 * new key to the specified keyring or update a matching key in that keyring.
47 *
48 * The keyring must be writable so that we can attach the key to it.
49 *
50 * If successful, the new key's serial number is returned, otherwise an error
51 * code is returned.
52 */
53SYSCALL_DEFINE5(add_key, const char __user *, _type,
54 const char __user *, _description,
55 const void __user *, _payload,
56 size_t, plen,
57 key_serial_t, ringid)
58{
59 key_ref_t keyring_ref, key_ref;
60 char type[32], *description;
61 void *payload;
62 long ret;
63 bool vm;
64
65 ret = -EINVAL;
66 if (plen > 1024 * 1024 - 1)
67 goto error;
68
69 /* draw all the data into kernel space */
70 ret = key_get_type_from_user(type, _type, sizeof(type));
71 if (ret < 0)
72 goto error;
73
74 description = strndup_user(_description, PAGE_SIZE);
75 if (IS_ERR(description)) {
76 ret = PTR_ERR(description);
77 goto error;
78 }
79
80 /* pull the payload in if one was supplied */
81 payload = NULL;
82
83 vm = false;
84 if (_payload) {
85 ret = -ENOMEM;
86 payload = kmalloc(plen, GFP_KERNEL);
87 if (!payload) {
88 if (plen <= PAGE_SIZE)
89 goto error2;
90 vm = true;
91 payload = vmalloc(plen);
92 if (!payload)
93 goto error2;
94 }
95
96 ret = -EFAULT;
97 if (copy_from_user(payload, _payload, plen) != 0)
98 goto error3;
99 }
100
101 /* find the target keyring (which must be writable) */
102 keyring_ref = lookup_user_key(ringid, KEY_LOOKUP_CREATE, KEY_WRITE);
103 if (IS_ERR(keyring_ref)) {
104 ret = PTR_ERR(keyring_ref);
105 goto error3;
106 }
107
108 /* create or update the requested key and add it to the target
109 * keyring */
110 key_ref = key_create_or_update(keyring_ref, type, description,
111 payload, plen, KEY_PERM_UNDEF,
112 KEY_ALLOC_IN_QUOTA);
113 if (!IS_ERR(key_ref)) {
114 ret = key_ref_to_ptr(key_ref)->serial;
115 key_ref_put(key_ref);
116 }
117 else {
118 ret = PTR_ERR(key_ref);
119 }
120
121 key_ref_put(keyring_ref);
122 error3:
123 if (!vm)
124 kfree(payload);
125 else
126 vfree(payload);
127 error2:
128 kfree(description);
129 error:
130 return ret;
131}
132
133/*
134 * Search the process keyrings and keyring trees linked from those for a
135 * matching key. Keyrings must have appropriate Search permission to be
136 * searched.
137 *
138 * If a key is found, it will be attached to the destination keyring if there's
139 * one specified and the serial number of the key will be returned.
140 *
141 * If no key is found, /sbin/request-key will be invoked if _callout_info is
142 * non-NULL in an attempt to create a key. The _callout_info string will be
143 * passed to /sbin/request-key to aid with completing the request. If the
144 * _callout_info string is "" then it will be changed to "-".
145 */
146SYSCALL_DEFINE4(request_key, const char __user *, _type,
147 const char __user *, _description,
148 const char __user *, _callout_info,
149 key_serial_t, destringid)
150{
151 struct key_type *ktype;
152 struct key *key;
153 key_ref_t dest_ref;
154 size_t callout_len;
155 char type[32], *description, *callout_info;
156 long ret;
157
158 /* pull the type into kernel space */
159 ret = key_get_type_from_user(type, _type, sizeof(type));
160 if (ret < 0)
161 goto error;
162
163 /* pull the description into kernel space */
164 description = strndup_user(_description, PAGE_SIZE);
165 if (IS_ERR(description)) {
166 ret = PTR_ERR(description);
167 goto error;
168 }
169
170 /* pull the callout info into kernel space */
171 callout_info = NULL;
172 callout_len = 0;
173 if (_callout_info) {
174 callout_info = strndup_user(_callout_info, PAGE_SIZE);
175 if (IS_ERR(callout_info)) {
176 ret = PTR_ERR(callout_info);
177 goto error2;
178 }
179 callout_len = strlen(callout_info);
180 }
181
182 /* get the destination keyring if specified */
183 dest_ref = NULL;
184 if (destringid) {
185 dest_ref = lookup_user_key(destringid, KEY_LOOKUP_CREATE,
186 KEY_WRITE);
187 if (IS_ERR(dest_ref)) {
188 ret = PTR_ERR(dest_ref);
189 goto error3;
190 }
191 }
192
193 /* find the key type */
194 ktype = key_type_lookup(type);
195 if (IS_ERR(ktype)) {
196 ret = PTR_ERR(ktype);
197 goto error4;
198 }
199
200 /* do the search */
201 key = request_key_and_link(ktype, description, callout_info,
202 callout_len, NULL, key_ref_to_ptr(dest_ref),
203 KEY_ALLOC_IN_QUOTA);
204 if (IS_ERR(key)) {
205 ret = PTR_ERR(key);
206 goto error5;
207 }
208
209 /* wait for the key to finish being constructed */
210 ret = wait_for_key_construction(key, 1);
211 if (ret < 0)
212 goto error6;
213
214 ret = key->serial;
215
216error6:
217 key_put(key);
218error5:
219 key_type_put(ktype);
220error4:
221 key_ref_put(dest_ref);
222error3:
223 kfree(callout_info);
224error2:
225 kfree(description);
226error:
227 return ret;
228}
229
230/*
231 * Get the ID of the specified process keyring.
232 *
233 * The requested keyring must have search permission to be found.
234 *
235 * If successful, the ID of the requested keyring will be returned.
236 */
237long keyctl_get_keyring_ID(key_serial_t id, int create)
238{
239 key_ref_t key_ref;
240 unsigned long lflags;
241 long ret;
242
243 lflags = create ? KEY_LOOKUP_CREATE : 0;
244 key_ref = lookup_user_key(id, lflags, KEY_SEARCH);
245 if (IS_ERR(key_ref)) {
246 ret = PTR_ERR(key_ref);
247 goto error;
248 }
249
250 ret = key_ref_to_ptr(key_ref)->serial;
251 key_ref_put(key_ref);
252error:
253 return ret;
254}
255
256/*
257 * Join a (named) session keyring.
258 *
259 * Create and join an anonymous session keyring or join a named session
260 * keyring, creating it if necessary. A named session keyring must have Search
261 * permission for it to be joined. Session keyrings without this permit will
262 * be skipped over.
263 *
264 * If successful, the ID of the joined session keyring will be returned.
265 */
266long keyctl_join_session_keyring(const char __user *_name)
267{
268 char *name;
269 long ret;
270
271 /* fetch the name from userspace */
272 name = NULL;
273 if (_name) {
274 name = strndup_user(_name, PAGE_SIZE);
275 if (IS_ERR(name)) {
276 ret = PTR_ERR(name);
277 goto error;
278 }
279 }
280
281 /* join the session */
282 ret = join_session_keyring(name);
283 kfree(name);
284
285error:
286 return ret;
287}
288
289/*
290 * Update a key's data payload from the given data.
291 *
292 * The key must grant the caller Write permission and the key type must support
293 * updating for this to work. A negative key can be positively instantiated
294 * with this call.
295 *
296 * If successful, 0 will be returned. If the key type does not support
297 * updating, then -EOPNOTSUPP will be returned.
298 */
299long keyctl_update_key(key_serial_t id,
300 const void __user *_payload,
301 size_t plen)
302{
303 key_ref_t key_ref;
304 void *payload;
305 long ret;
306
307 ret = -EINVAL;
308 if (plen > PAGE_SIZE)
309 goto error;
310
311 /* pull the payload in if one was supplied */
312 payload = NULL;
313 if (_payload) {
314 ret = -ENOMEM;
315 payload = kmalloc(plen, GFP_KERNEL);
316 if (!payload)
317 goto error;
318
319 ret = -EFAULT;
320 if (copy_from_user(payload, _payload, plen) != 0)
321 goto error2;
322 }
323
324 /* find the target key (which must be writable) */
325 key_ref = lookup_user_key(id, 0, KEY_WRITE);
326 if (IS_ERR(key_ref)) {
327 ret = PTR_ERR(key_ref);
328 goto error2;
329 }
330
331 /* update the key */
332 ret = key_update(key_ref, payload, plen);
333
334 key_ref_put(key_ref);
335error2:
336 kfree(payload);
337error:
338 return ret;
339}
340
341/*
342 * Revoke a key.
343 *
344 * The key must be grant the caller Write or Setattr permission for this to
345 * work. The key type should give up its quota claim when revoked. The key
346 * and any links to the key will be automatically garbage collected after a
347 * certain amount of time (/proc/sys/kernel/keys/gc_delay).
348 *
349 * If successful, 0 is returned.
350 */
351long keyctl_revoke_key(key_serial_t id)
352{
353 key_ref_t key_ref;
354 long ret;
355
356 key_ref = lookup_user_key(id, 0, KEY_WRITE);
357 if (IS_ERR(key_ref)) {
358 ret = PTR_ERR(key_ref);
359 if (ret != -EACCES)
360 goto error;
361 key_ref = lookup_user_key(id, 0, KEY_SETATTR);
362 if (IS_ERR(key_ref)) {
363 ret = PTR_ERR(key_ref);
364 goto error;
365 }
366 }
367
368 key_revoke(key_ref_to_ptr(key_ref));
369 ret = 0;
370
371 key_ref_put(key_ref);
372error:
373 return ret;
374}
375
376/*
377 * Clear the specified keyring, creating an empty process keyring if one of the
378 * special keyring IDs is used.
379 *
380 * The keyring must grant the caller Write permission for this to work. If
381 * successful, 0 will be returned.
382 */
383long keyctl_keyring_clear(key_serial_t ringid)
384{
385 key_ref_t keyring_ref;
386 long ret;
387
388 keyring_ref = lookup_user_key(ringid, KEY_LOOKUP_CREATE, KEY_WRITE);
389 if (IS_ERR(keyring_ref)) {
390 ret = PTR_ERR(keyring_ref);
391 goto error;
392 }
393
394 ret = keyring_clear(key_ref_to_ptr(keyring_ref));
395
396 key_ref_put(keyring_ref);
397error:
398 return ret;
399}
400
401/*
402 * Create a link from a keyring to a key if there's no matching key in the
403 * keyring, otherwise replace the link to the matching key with a link to the
404 * new key.
405 *
406 * The key must grant the caller Link permission and the the keyring must grant
407 * the caller Write permission. Furthermore, if an additional link is created,
408 * the keyring's quota will be extended.
409 *
410 * If successful, 0 will be returned.
411 */
412long keyctl_keyring_link(key_serial_t id, key_serial_t ringid)
413{
414 key_ref_t keyring_ref, key_ref;
415 long ret;
416
417 keyring_ref = lookup_user_key(ringid, KEY_LOOKUP_CREATE, KEY_WRITE);
418 if (IS_ERR(keyring_ref)) {
419 ret = PTR_ERR(keyring_ref);
420 goto error;
421 }
422
423 key_ref = lookup_user_key(id, KEY_LOOKUP_CREATE, KEY_LINK);
424 if (IS_ERR(key_ref)) {
425 ret = PTR_ERR(key_ref);
426 goto error2;
427 }
428
429 ret = key_link(key_ref_to_ptr(keyring_ref), key_ref_to_ptr(key_ref));
430
431 key_ref_put(key_ref);
432error2:
433 key_ref_put(keyring_ref);
434error:
435 return ret;
436}
437
438/*
439 * Unlink a key from a keyring.
440 *
441 * The keyring must grant the caller Write permission for this to work; the key
442 * itself need not grant the caller anything. If the last link to a key is
443 * removed then that key will be scheduled for destruction.
444 *
445 * If successful, 0 will be returned.
446 */
447long keyctl_keyring_unlink(key_serial_t id, key_serial_t ringid)
448{
449 key_ref_t keyring_ref, key_ref;
450 long ret;
451
452 keyring_ref = lookup_user_key(ringid, 0, KEY_WRITE);
453 if (IS_ERR(keyring_ref)) {
454 ret = PTR_ERR(keyring_ref);
455 goto error;
456 }
457
458 key_ref = lookup_user_key(id, KEY_LOOKUP_FOR_UNLINK, 0);
459 if (IS_ERR(key_ref)) {
460 ret = PTR_ERR(key_ref);
461 goto error2;
462 }
463
464 ret = key_unlink(key_ref_to_ptr(keyring_ref), key_ref_to_ptr(key_ref));
465
466 key_ref_put(key_ref);
467error2:
468 key_ref_put(keyring_ref);
469error:
470 return ret;
471}
472
473/*
474 * Return a description of a key to userspace.
475 *
476 * The key must grant the caller View permission for this to work.
477 *
478 * If there's a buffer, we place up to buflen bytes of data into it formatted
479 * in the following way:
480 *
481 * type;uid;gid;perm;description<NUL>
482 *
483 * If successful, we return the amount of description available, irrespective
484 * of how much we may have copied into the buffer.
485 */
486long keyctl_describe_key(key_serial_t keyid,
487 char __user *buffer,
488 size_t buflen)
489{
490 struct key *key, *instkey;
491 key_ref_t key_ref;
492 char *tmpbuf;
493 long ret;
494
495 key_ref = lookup_user_key(keyid, KEY_LOOKUP_PARTIAL, KEY_VIEW);
496 if (IS_ERR(key_ref)) {
497 /* viewing a key under construction is permitted if we have the
498 * authorisation token handy */
499 if (PTR_ERR(key_ref) == -EACCES) {
500 instkey = key_get_instantiation_authkey(keyid);
501 if (!IS_ERR(instkey)) {
502 key_put(instkey);
503 key_ref = lookup_user_key(keyid,
504 KEY_LOOKUP_PARTIAL,
505 0);
506 if (!IS_ERR(key_ref))
507 goto okay;
508 }
509 }
510
511 ret = PTR_ERR(key_ref);
512 goto error;
513 }
514
515okay:
516 /* calculate how much description we're going to return */
517 ret = -ENOMEM;
518 tmpbuf = kmalloc(PAGE_SIZE, GFP_KERNEL);
519 if (!tmpbuf)
520 goto error2;
521
522 key = key_ref_to_ptr(key_ref);
523
524 ret = snprintf(tmpbuf, PAGE_SIZE - 1,
525 "%s;%d;%d;%08x;%s",
526 key->type->name,
527 key->uid,
528 key->gid,
529 key->perm,
530 key->description ?: "");
531
532 /* include a NUL char at the end of the data */
533 if (ret > PAGE_SIZE - 1)
534 ret = PAGE_SIZE - 1;
535 tmpbuf[ret] = 0;
536 ret++;
537
538 /* consider returning the data */
539 if (buffer && buflen > 0) {
540 if (buflen > ret)
541 buflen = ret;
542
543 if (copy_to_user(buffer, tmpbuf, buflen) != 0)
544 ret = -EFAULT;
545 }
546
547 kfree(tmpbuf);
548error2:
549 key_ref_put(key_ref);
550error:
551 return ret;
552}
553
554/*
555 * Search the specified keyring and any keyrings it links to for a matching
556 * key. Only keyrings that grant the caller Search permission will be searched
557 * (this includes the starting keyring). Only keys with Search permission can
558 * be found.
559 *
560 * If successful, the found key will be linked to the destination keyring if
561 * supplied and the key has Link permission, and the found key ID will be
562 * returned.
563 */
564long keyctl_keyring_search(key_serial_t ringid,
565 const char __user *_type,
566 const char __user *_description,
567 key_serial_t destringid)
568{
569 struct key_type *ktype;
570 key_ref_t keyring_ref, key_ref, dest_ref;
571 char type[32], *description;
572 long ret;
573
574 /* pull the type and description into kernel space */
575 ret = key_get_type_from_user(type, _type, sizeof(type));
576 if (ret < 0)
577 goto error;
578
579 description = strndup_user(_description, PAGE_SIZE);
580 if (IS_ERR(description)) {
581 ret = PTR_ERR(description);
582 goto error;
583 }
584
585 /* get the keyring at which to begin the search */
586 keyring_ref = lookup_user_key(ringid, 0, KEY_SEARCH);
587 if (IS_ERR(keyring_ref)) {
588 ret = PTR_ERR(keyring_ref);
589 goto error2;
590 }
591
592 /* get the destination keyring if specified */
593 dest_ref = NULL;
594 if (destringid) {
595 dest_ref = lookup_user_key(destringid, KEY_LOOKUP_CREATE,
596 KEY_WRITE);
597 if (IS_ERR(dest_ref)) {
598 ret = PTR_ERR(dest_ref);
599 goto error3;
600 }
601 }
602
603 /* find the key type */
604 ktype = key_type_lookup(type);
605 if (IS_ERR(ktype)) {
606 ret = PTR_ERR(ktype);
607 goto error4;
608 }
609
610 /* do the search */
611 key_ref = keyring_search(keyring_ref, ktype, description);
612 if (IS_ERR(key_ref)) {
613 ret = PTR_ERR(key_ref);
614
615 /* treat lack or presence of a negative key the same */
616 if (ret == -EAGAIN)
617 ret = -ENOKEY;
618 goto error5;
619 }
620
621 /* link the resulting key to the destination keyring if we can */
622 if (dest_ref) {
623 ret = key_permission(key_ref, KEY_LINK);
624 if (ret < 0)
625 goto error6;
626
627 ret = key_link(key_ref_to_ptr(dest_ref), key_ref_to_ptr(key_ref));
628 if (ret < 0)
629 goto error6;
630 }
631
632 ret = key_ref_to_ptr(key_ref)->serial;
633
634error6:
635 key_ref_put(key_ref);
636error5:
637 key_type_put(ktype);
638error4:
639 key_ref_put(dest_ref);
640error3:
641 key_ref_put(keyring_ref);
642error2:
643 kfree(description);
644error:
645 return ret;
646}
647
648/*
649 * Read a key's payload.
650 *
651 * The key must either grant the caller Read permission, or it must grant the
652 * caller Search permission when searched for from the process keyrings.
653 *
654 * If successful, we place up to buflen bytes of data into the buffer, if one
655 * is provided, and return the amount of data that is available in the key,
656 * irrespective of how much we copied into the buffer.
657 */
658long keyctl_read_key(key_serial_t keyid, char __user *buffer, size_t buflen)
659{
660 struct key *key;
661 key_ref_t key_ref;
662 long ret;
663
664 /* find the key first */
665 key_ref = lookup_user_key(keyid, 0, 0);
666 if (IS_ERR(key_ref)) {
667 ret = -ENOKEY;
668 goto error;
669 }
670
671 key = key_ref_to_ptr(key_ref);
672
673 /* see if we can read it directly */
674 ret = key_permission(key_ref, KEY_READ);
675 if (ret == 0)
676 goto can_read_key;
677 if (ret != -EACCES)
678 goto error;
679
680 /* we can't; see if it's searchable from this process's keyrings
681 * - we automatically take account of the fact that it may be
682 * dangling off an instantiation key
683 */
684 if (!is_key_possessed(key_ref)) {
685 ret = -EACCES;
686 goto error2;
687 }
688
689 /* the key is probably readable - now try to read it */
690can_read_key:
691 ret = key_validate(key);
692 if (ret == 0) {
693 ret = -EOPNOTSUPP;
694 if (key->type->read) {
695 /* read the data with the semaphore held (since we
696 * might sleep) */
697 down_read(&key->sem);
698 ret = key->type->read(key, buffer, buflen);
699 up_read(&key->sem);
700 }
701 }
702
703error2:
704 key_put(key);
705error:
706 return ret;
707}
708
709/*
710 * Change the ownership of a key
711 *
712 * The key must grant the caller Setattr permission for this to work, though
713 * the key need not be fully instantiated yet. For the UID to be changed, or
714 * for the GID to be changed to a group the caller is not a member of, the
715 * caller must have sysadmin capability. If either uid or gid is -1 then that
716 * attribute is not changed.
717 *
718 * If the UID is to be changed, the new user must have sufficient quota to
719 * accept the key. The quota deduction will be removed from the old user to
720 * the new user should the attribute be changed.
721 *
722 * If successful, 0 will be returned.
723 */
724long keyctl_chown_key(key_serial_t id, uid_t uid, gid_t gid)
725{
726 struct key_user *newowner, *zapowner = NULL;
727 struct key *key;
728 key_ref_t key_ref;
729 long ret;
730
731 ret = 0;
732 if (uid == (uid_t) -1 && gid == (gid_t) -1)
733 goto error;
734
735 key_ref = lookup_user_key(id, KEY_LOOKUP_CREATE | KEY_LOOKUP_PARTIAL,
736 KEY_SETATTR);
737 if (IS_ERR(key_ref)) {
738 ret = PTR_ERR(key_ref);
739 goto error;
740 }
741
742 key = key_ref_to_ptr(key_ref);
743
744 /* make the changes with the locks held to prevent chown/chown races */
745 ret = -EACCES;
746 down_write(&key->sem);
747
748 if (!capable(CAP_SYS_ADMIN)) {
749 /* only the sysadmin can chown a key to some other UID */
750 if (uid != (uid_t) -1 && key->uid != uid)
751 goto error_put;
752
753 /* only the sysadmin can set the key's GID to a group other
754 * than one of those that the current process subscribes to */
755 if (gid != (gid_t) -1 && gid != key->gid && !in_group_p(gid))
756 goto error_put;
757 }
758
759 /* change the UID */
760 if (uid != (uid_t) -1 && uid != key->uid) {
761 ret = -ENOMEM;
762 newowner = key_user_lookup(uid, current_user_ns());
763 if (!newowner)
764 goto error_put;
765
766 /* transfer the quota burden to the new user */
767 if (test_bit(KEY_FLAG_IN_QUOTA, &key->flags)) {
768 unsigned maxkeys = (uid == 0) ?
769 key_quota_root_maxkeys : key_quota_maxkeys;
770 unsigned maxbytes = (uid == 0) ?
771 key_quota_root_maxbytes : key_quota_maxbytes;
772
773 spin_lock(&newowner->lock);
774 if (newowner->qnkeys + 1 >= maxkeys ||
775 newowner->qnbytes + key->quotalen >= maxbytes ||
776 newowner->qnbytes + key->quotalen <
777 newowner->qnbytes)
778 goto quota_overrun;
779
780 newowner->qnkeys++;
781 newowner->qnbytes += key->quotalen;
782 spin_unlock(&newowner->lock);
783
784 spin_lock(&key->user->lock);
785 key->user->qnkeys--;
786 key->user->qnbytes -= key->quotalen;
787 spin_unlock(&key->user->lock);
788 }
789
790 atomic_dec(&key->user->nkeys);
791 atomic_inc(&newowner->nkeys);
792
793 if (test_bit(KEY_FLAG_INSTANTIATED, &key->flags)) {
794 atomic_dec(&key->user->nikeys);
795 atomic_inc(&newowner->nikeys);
796 }
797
798 zapowner = key->user;
799 key->user = newowner;
800 key->uid = uid;
801 }
802
803 /* change the GID */
804 if (gid != (gid_t) -1)
805 key->gid = gid;
806
807 ret = 0;
808
809error_put:
810 up_write(&key->sem);
811 key_put(key);
812 if (zapowner)
813 key_user_put(zapowner);
814error:
815 return ret;
816
817quota_overrun:
818 spin_unlock(&newowner->lock);
819 zapowner = newowner;
820 ret = -EDQUOT;
821 goto error_put;
822}
823
824/*
825 * Change the permission mask on a key.
826 *
827 * The key must grant the caller Setattr permission for this to work, though
828 * the key need not be fully instantiated yet. If the caller does not have
829 * sysadmin capability, it may only change the permission on keys that it owns.
830 */
831long keyctl_setperm_key(key_serial_t id, key_perm_t perm)
832{
833 struct key *key;
834 key_ref_t key_ref;
835 long ret;
836
837 ret = -EINVAL;
838 if (perm & ~(KEY_POS_ALL | KEY_USR_ALL | KEY_GRP_ALL | KEY_OTH_ALL))
839 goto error;
840
841 key_ref = lookup_user_key(id, KEY_LOOKUP_CREATE | KEY_LOOKUP_PARTIAL,
842 KEY_SETATTR);
843 if (IS_ERR(key_ref)) {
844 ret = PTR_ERR(key_ref);
845 goto error;
846 }
847
848 key = key_ref_to_ptr(key_ref);
849
850 /* make the changes with the locks held to prevent chown/chmod races */
851 ret = -EACCES;
852 down_write(&key->sem);
853
854 /* if we're not the sysadmin, we can only change a key that we own */
855 if (capable(CAP_SYS_ADMIN) || key->uid == current_fsuid()) {
856 key->perm = perm;
857 ret = 0;
858 }
859
860 up_write(&key->sem);
861 key_put(key);
862error:
863 return ret;
864}
865
866/*
867 * Get the destination keyring for instantiation and check that the caller has
868 * Write permission on it.
869 */
870static long get_instantiation_keyring(key_serial_t ringid,
871 struct request_key_auth *rka,
872 struct key **_dest_keyring)
873{
874 key_ref_t dkref;
875
876 *_dest_keyring = NULL;
877
878 /* just return a NULL pointer if we weren't asked to make a link */
879 if (ringid == 0)
880 return 0;
881
882 /* if a specific keyring is nominated by ID, then use that */
883 if (ringid > 0) {
884 dkref = lookup_user_key(ringid, KEY_LOOKUP_CREATE, KEY_WRITE);
885 if (IS_ERR(dkref))
886 return PTR_ERR(dkref);
887 *_dest_keyring = key_ref_to_ptr(dkref);
888 return 0;
889 }
890
891 if (ringid == KEY_SPEC_REQKEY_AUTH_KEY)
892 return -EINVAL;
893
894 /* otherwise specify the destination keyring recorded in the
895 * authorisation key (any KEY_SPEC_*_KEYRING) */
896 if (ringid >= KEY_SPEC_REQUESTOR_KEYRING) {
897 *_dest_keyring = key_get(rka->dest_keyring);
898 return 0;
899 }
900
901 return -ENOKEY;
902}
903
904/*
905 * Change the request_key authorisation key on the current process.
906 */
907static int keyctl_change_reqkey_auth(struct key *key)
908{
909 struct cred *new;
910
911 new = prepare_creds();
912 if (!new)
913 return -ENOMEM;
914
915 key_put(new->request_key_auth);
916 new->request_key_auth = key_get(key);
917
918 return commit_creds(new);
919}
920
921/*
922 * Copy the iovec data from userspace
923 */
924static long copy_from_user_iovec(void *buffer, const struct iovec *iov,
925 unsigned ioc)
926{
927 for (; ioc > 0; ioc--) {
928 if (copy_from_user(buffer, iov->iov_base, iov->iov_len) != 0)
929 return -EFAULT;
930 buffer += iov->iov_len;
931 iov++;
932 }
933 return 0;
934}
935
936/*
937 * Instantiate a key with the specified payload and link the key into the
938 * destination keyring if one is given.
939 *
940 * The caller must have the appropriate instantiation permit set for this to
941 * work (see keyctl_assume_authority). No other permissions are required.
942 *
943 * If successful, 0 will be returned.
944 */
945long keyctl_instantiate_key_common(key_serial_t id,
946 const struct iovec *payload_iov,
947 unsigned ioc,
948 size_t plen,
949 key_serial_t ringid)
950{
951 const struct cred *cred = current_cred();
952 struct request_key_auth *rka;
953 struct key *instkey, *dest_keyring;
954 void *payload;
955 long ret;
956 bool vm = false;
957
958 kenter("%d,,%zu,%d", id, plen, ringid);
959
960 ret = -EINVAL;
961 if (plen > 1024 * 1024 - 1)
962 goto error;
963
964 /* the appropriate instantiation authorisation key must have been
965 * assumed before calling this */
966 ret = -EPERM;
967 instkey = cred->request_key_auth;
968 if (!instkey)
969 goto error;
970
971 rka = instkey->payload.data;
972 if (rka->target_key->serial != id)
973 goto error;
974
975 /* pull the payload in if one was supplied */
976 payload = NULL;
977
978 if (payload_iov) {
979 ret = -ENOMEM;
980 payload = kmalloc(plen, GFP_KERNEL);
981 if (!payload) {
982 if (plen <= PAGE_SIZE)
983 goto error;
984 vm = true;
985 payload = vmalloc(plen);
986 if (!payload)
987 goto error;
988 }
989
990 ret = copy_from_user_iovec(payload, payload_iov, ioc);
991 if (ret < 0)
992 goto error2;
993 }
994
995 /* find the destination keyring amongst those belonging to the
996 * requesting task */
997 ret = get_instantiation_keyring(ringid, rka, &dest_keyring);
998 if (ret < 0)
999 goto error2;
1000
1001 /* instantiate the key and link it into a keyring */
1002 ret = key_instantiate_and_link(rka->target_key, payload, plen,
1003 dest_keyring, instkey);
1004
1005 key_put(dest_keyring);
1006
1007 /* discard the assumed authority if it's just been disabled by
1008 * instantiation of the key */
1009 if (ret == 0)
1010 keyctl_change_reqkey_auth(NULL);
1011
1012error2:
1013 if (!vm)
1014 kfree(payload);
1015 else
1016 vfree(payload);
1017error:
1018 return ret;
1019}
1020
1021/*
1022 * Instantiate a key with the specified payload and link the key into the
1023 * destination keyring if one is given.
1024 *
1025 * The caller must have the appropriate instantiation permit set for this to
1026 * work (see keyctl_assume_authority). No other permissions are required.
1027 *
1028 * If successful, 0 will be returned.
1029 */
1030long keyctl_instantiate_key(key_serial_t id,
1031 const void __user *_payload,
1032 size_t plen,
1033 key_serial_t ringid)
1034{
1035 if (_payload && plen) {
1036 struct iovec iov[1] = {
1037 [0].iov_base = (void __user *)_payload,
1038 [0].iov_len = plen
1039 };
1040
1041 return keyctl_instantiate_key_common(id, iov, 1, plen, ringid);
1042 }
1043
1044 return keyctl_instantiate_key_common(id, NULL, 0, 0, ringid);
1045}
1046
1047/*
1048 * Instantiate a key with the specified multipart payload and link the key into
1049 * the destination keyring if one is given.
1050 *
1051 * The caller must have the appropriate instantiation permit set for this to
1052 * work (see keyctl_assume_authority). No other permissions are required.
1053 *
1054 * If successful, 0 will be returned.
1055 */
1056long keyctl_instantiate_key_iov(key_serial_t id,
1057 const struct iovec __user *_payload_iov,
1058 unsigned ioc,
1059 key_serial_t ringid)
1060{
1061 struct iovec iovstack[UIO_FASTIOV], *iov = iovstack;
1062 long ret;
1063
1064 if (_payload_iov == 0 || ioc == 0)
1065 goto no_payload;
1066
1067 ret = rw_copy_check_uvector(WRITE, _payload_iov, ioc,
1068 ARRAY_SIZE(iovstack), iovstack, &iov);
1069 if (ret < 0)
1070 return ret;
1071 if (ret == 0)
1072 goto no_payload_free;
1073
1074 ret = keyctl_instantiate_key_common(id, iov, ioc, ret, ringid);
1075
1076 if (iov != iovstack)
1077 kfree(iov);
1078 return ret;
1079
1080no_payload_free:
1081 if (iov != iovstack)
1082 kfree(iov);
1083no_payload:
1084 return keyctl_instantiate_key_common(id, NULL, 0, 0, ringid);
1085}
1086
1087/*
1088 * Negatively instantiate the key with the given timeout (in seconds) and link
1089 * the key into the destination keyring if one is given.
1090 *
1091 * The caller must have the appropriate instantiation permit set for this to
1092 * work (see keyctl_assume_authority). No other permissions are required.
1093 *
1094 * The key and any links to the key will be automatically garbage collected
1095 * after the timeout expires.
1096 *
1097 * Negative keys are used to rate limit repeated request_key() calls by causing
1098 * them to return -ENOKEY until the negative key expires.
1099 *
1100 * If successful, 0 will be returned.
1101 */
1102long keyctl_negate_key(key_serial_t id, unsigned timeout, key_serial_t ringid)
1103{
1104 return keyctl_reject_key(id, timeout, ENOKEY, ringid);
1105}
1106
1107/*
1108 * Negatively instantiate the key with the given timeout (in seconds) and error
1109 * code and link the key into the destination keyring if one is given.
1110 *
1111 * The caller must have the appropriate instantiation permit set for this to
1112 * work (see keyctl_assume_authority). No other permissions are required.
1113 *
1114 * The key and any links to the key will be automatically garbage collected
1115 * after the timeout expires.
1116 *
1117 * Negative keys are used to rate limit repeated request_key() calls by causing
1118 * them to return the specified error code until the negative key expires.
1119 *
1120 * If successful, 0 will be returned.
1121 */
1122long keyctl_reject_key(key_serial_t id, unsigned timeout, unsigned error,
1123 key_serial_t ringid)
1124{
1125 const struct cred *cred = current_cred();
1126 struct request_key_auth *rka;
1127 struct key *instkey, *dest_keyring;
1128 long ret;
1129
1130 kenter("%d,%u,%u,%d", id, timeout, error, ringid);
1131
1132 /* must be a valid error code and mustn't be a kernel special */
1133 if (error <= 0 ||
1134 error >= MAX_ERRNO ||
1135 error == ERESTARTSYS ||
1136 error == ERESTARTNOINTR ||
1137 error == ERESTARTNOHAND ||
1138 error == ERESTART_RESTARTBLOCK)
1139 return -EINVAL;
1140
1141 /* the appropriate instantiation authorisation key must have been
1142 * assumed before calling this */
1143 ret = -EPERM;
1144 instkey = cred->request_key_auth;
1145 if (!instkey)
1146 goto error;
1147
1148 rka = instkey->payload.data;
1149 if (rka->target_key->serial != id)
1150 goto error;
1151
1152 /* find the destination keyring if present (which must also be
1153 * writable) */
1154 ret = get_instantiation_keyring(ringid, rka, &dest_keyring);
1155 if (ret < 0)
1156 goto error;
1157
1158 /* instantiate the key and link it into a keyring */
1159 ret = key_reject_and_link(rka->target_key, timeout, error,
1160 dest_keyring, instkey);
1161
1162 key_put(dest_keyring);
1163
1164 /* discard the assumed authority if it's just been disabled by
1165 * instantiation of the key */
1166 if (ret == 0)
1167 keyctl_change_reqkey_auth(NULL);
1168
1169error:
1170 return ret;
1171}
1172
1173/*
1174 * Read or set the default keyring in which request_key() will cache keys and
1175 * return the old setting.
1176 *
1177 * If a process keyring is specified then this will be created if it doesn't
1178 * yet exist. The old setting will be returned if successful.
1179 */
1180long keyctl_set_reqkey_keyring(int reqkey_defl)
1181{
1182 struct cred *new;
1183 int ret, old_setting;
1184
1185 old_setting = current_cred_xxx(jit_keyring);
1186
1187 if (reqkey_defl == KEY_REQKEY_DEFL_NO_CHANGE)
1188 return old_setting;
1189
1190 new = prepare_creds();
1191 if (!new)
1192 return -ENOMEM;
1193
1194 switch (reqkey_defl) {
1195 case KEY_REQKEY_DEFL_THREAD_KEYRING:
1196 ret = install_thread_keyring_to_cred(new);
1197 if (ret < 0)
1198 goto error;
1199 goto set;
1200
1201 case KEY_REQKEY_DEFL_PROCESS_KEYRING:
1202 ret = install_process_keyring_to_cred(new);
1203 if (ret < 0) {
1204 if (ret != -EEXIST)
1205 goto error;
1206 ret = 0;
1207 }
1208 goto set;
1209
1210 case KEY_REQKEY_DEFL_DEFAULT:
1211 case KEY_REQKEY_DEFL_SESSION_KEYRING:
1212 case KEY_REQKEY_DEFL_USER_KEYRING:
1213 case KEY_REQKEY_DEFL_USER_SESSION_KEYRING:
1214 case KEY_REQKEY_DEFL_REQUESTOR_KEYRING:
1215 goto set;
1216
1217 case KEY_REQKEY_DEFL_NO_CHANGE:
1218 case KEY_REQKEY_DEFL_GROUP_KEYRING:
1219 default:
1220 ret = -EINVAL;
1221 goto error;
1222 }
1223
1224set:
1225 new->jit_keyring = reqkey_defl;
1226 commit_creds(new);
1227 return old_setting;
1228error:
1229 abort_creds(new);
1230 return ret;
1231}
1232
1233/*
1234 * Set or clear the timeout on a key.
1235 *
1236 * Either the key must grant the caller Setattr permission or else the caller
1237 * must hold an instantiation authorisation token for the key.
1238 *
1239 * The timeout is either 0 to clear the timeout, or a number of seconds from
1240 * the current time. The key and any links to the key will be automatically
1241 * garbage collected after the timeout expires.
1242 *
1243 * If successful, 0 is returned.
1244 */
1245long keyctl_set_timeout(key_serial_t id, unsigned timeout)
1246{
1247 struct timespec now;
1248 struct key *key, *instkey;
1249 key_ref_t key_ref;
1250 time_t expiry;
1251 long ret;
1252
1253 key_ref = lookup_user_key(id, KEY_LOOKUP_CREATE | KEY_LOOKUP_PARTIAL,
1254 KEY_SETATTR);
1255 if (IS_ERR(key_ref)) {
1256 /* setting the timeout on a key under construction is permitted
1257 * if we have the authorisation token handy */
1258 if (PTR_ERR(key_ref) == -EACCES) {
1259 instkey = key_get_instantiation_authkey(id);
1260 if (!IS_ERR(instkey)) {
1261 key_put(instkey);
1262 key_ref = lookup_user_key(id,
1263 KEY_LOOKUP_PARTIAL,
1264 0);
1265 if (!IS_ERR(key_ref))
1266 goto okay;
1267 }
1268 }
1269
1270 ret = PTR_ERR(key_ref);
1271 goto error;
1272 }
1273
1274okay:
1275 key = key_ref_to_ptr(key_ref);
1276
1277 /* make the changes with the locks held to prevent races */
1278 down_write(&key->sem);
1279
1280 expiry = 0;
1281 if (timeout > 0) {
1282 now = current_kernel_time();
1283 expiry = now.tv_sec + timeout;
1284 }
1285
1286 key->expiry = expiry;
1287 key_schedule_gc(key->expiry + key_gc_delay);
1288
1289 up_write(&key->sem);
1290 key_put(key);
1291
1292 ret = 0;
1293error:
1294 return ret;
1295}
1296
1297/*
1298 * Assume (or clear) the authority to instantiate the specified key.
1299 *
1300 * This sets the authoritative token currently in force for key instantiation.
1301 * This must be done for a key to be instantiated. It has the effect of making
1302 * available all the keys from the caller of the request_key() that created a
1303 * key to request_key() calls made by the caller of this function.
1304 *
1305 * The caller must have the instantiation key in their process keyrings with a
1306 * Search permission grant available to the caller.
1307 *
1308 * If the ID given is 0, then the setting will be cleared and 0 returned.
1309 *
1310 * If the ID given has a matching an authorisation key, then that key will be
1311 * set and its ID will be returned. The authorisation key can be read to get
1312 * the callout information passed to request_key().
1313 */
1314long keyctl_assume_authority(key_serial_t id)
1315{
1316 struct key *authkey;
1317 long ret;
1318
1319 /* special key IDs aren't permitted */
1320 ret = -EINVAL;
1321 if (id < 0)
1322 goto error;
1323
1324 /* we divest ourselves of authority if given an ID of 0 */
1325 if (id == 0) {
1326 ret = keyctl_change_reqkey_auth(NULL);
1327 goto error;
1328 }
1329
1330 /* attempt to assume the authority temporarily granted to us whilst we
1331 * instantiate the specified key
1332 * - the authorisation key must be in the current task's keyrings
1333 * somewhere
1334 */
1335 authkey = key_get_instantiation_authkey(id);
1336 if (IS_ERR(authkey)) {
1337 ret = PTR_ERR(authkey);
1338 goto error;
1339 }
1340
1341 ret = keyctl_change_reqkey_auth(authkey);
1342 if (ret < 0)
1343 goto error;
1344 key_put(authkey);
1345
1346 ret = authkey->serial;
1347error:
1348 return ret;
1349}
1350
1351/*
1352 * Get a key's the LSM security label.
1353 *
1354 * The key must grant the caller View permission for this to work.
1355 *
1356 * If there's a buffer, then up to buflen bytes of data will be placed into it.
1357 *
1358 * If successful, the amount of information available will be returned,
1359 * irrespective of how much was copied (including the terminal NUL).
1360 */
1361long keyctl_get_security(key_serial_t keyid,
1362 char __user *buffer,
1363 size_t buflen)
1364{
1365 struct key *key, *instkey;
1366 key_ref_t key_ref;
1367 char *context;
1368 long ret;
1369
1370 key_ref = lookup_user_key(keyid, KEY_LOOKUP_PARTIAL, KEY_VIEW);
1371 if (IS_ERR(key_ref)) {
1372 if (PTR_ERR(key_ref) != -EACCES)
1373 return PTR_ERR(key_ref);
1374
1375 /* viewing a key under construction is also permitted if we
1376 * have the authorisation token handy */
1377 instkey = key_get_instantiation_authkey(keyid);
1378 if (IS_ERR(instkey))
1379 return PTR_ERR(instkey);
1380 key_put(instkey);
1381
1382 key_ref = lookup_user_key(keyid, KEY_LOOKUP_PARTIAL, 0);
1383 if (IS_ERR(key_ref))
1384 return PTR_ERR(key_ref);
1385 }
1386
1387 key = key_ref_to_ptr(key_ref);
1388 ret = security_key_getsecurity(key, &context);
1389 if (ret == 0) {
1390 /* if no information was returned, give userspace an empty
1391 * string */
1392 ret = 1;
1393 if (buffer && buflen > 0 &&
1394 copy_to_user(buffer, "", 1) != 0)
1395 ret = -EFAULT;
1396 } else if (ret > 0) {
1397 /* return as much data as there's room for */
1398 if (buffer && buflen > 0) {
1399 if (buflen > ret)
1400 buflen = ret;
1401
1402 if (copy_to_user(buffer, context, buflen) != 0)
1403 ret = -EFAULT;
1404 }
1405
1406 kfree(context);
1407 }
1408
1409 key_ref_put(key_ref);
1410 return ret;
1411}
1412
1413/*
1414 * Attempt to install the calling process's session keyring on the process's
1415 * parent process.
1416 *
1417 * The keyring must exist and must grant the caller LINK permission, and the
1418 * parent process must be single-threaded and must have the same effective
1419 * ownership as this process and mustn't be SUID/SGID.
1420 *
1421 * The keyring will be emplaced on the parent when it next resumes userspace.
1422 *
1423 * If successful, 0 will be returned.
1424 */
1425long keyctl_session_to_parent(void)
1426{
1427#ifdef TIF_NOTIFY_RESUME
1428 struct task_struct *me, *parent;
1429 const struct cred *mycred, *pcred;
1430 struct cred *cred, *oldcred;
1431 key_ref_t keyring_r;
1432 int ret;
1433
1434 keyring_r = lookup_user_key(KEY_SPEC_SESSION_KEYRING, 0, KEY_LINK);
1435 if (IS_ERR(keyring_r))
1436 return PTR_ERR(keyring_r);
1437
1438 /* our parent is going to need a new cred struct, a new tgcred struct
1439 * and new security data, so we allocate them here to prevent ENOMEM in
1440 * our parent */
1441 ret = -ENOMEM;
1442 cred = cred_alloc_blank();
1443 if (!cred)
1444 goto error_keyring;
1445
1446 cred->tgcred->session_keyring = key_ref_to_ptr(keyring_r);
1447 keyring_r = NULL;
1448
1449 me = current;
1450 rcu_read_lock();
1451 write_lock_irq(&tasklist_lock);
1452
1453 parent = me->real_parent;
1454 ret = -EPERM;
1455
1456 /* the parent mustn't be init and mustn't be a kernel thread */
1457 if (parent->pid <= 1 || !parent->mm)
1458 goto not_permitted;
1459
1460 /* the parent must be single threaded */
1461 if (!thread_group_empty(parent))
1462 goto not_permitted;
1463
1464 /* the parent and the child must have different session keyrings or
1465 * there's no point */
1466 mycred = current_cred();
1467 pcred = __task_cred(parent);
1468 if (mycred == pcred ||
1469 mycred->tgcred->session_keyring == pcred->tgcred->session_keyring)
1470 goto already_same;
1471
1472 /* the parent must have the same effective ownership and mustn't be
1473 * SUID/SGID */
1474 if (pcred->uid != mycred->euid ||
1475 pcred->euid != mycred->euid ||
1476 pcred->suid != mycred->euid ||
1477 pcred->gid != mycred->egid ||
1478 pcred->egid != mycred->egid ||
1479 pcred->sgid != mycred->egid)
1480 goto not_permitted;
1481
1482 /* the keyrings must have the same UID */
1483 if ((pcred->tgcred->session_keyring &&
1484 pcred->tgcred->session_keyring->uid != mycred->euid) ||
1485 mycred->tgcred->session_keyring->uid != mycred->euid)
1486 goto not_permitted;
1487
1488 /* if there's an already pending keyring replacement, then we replace
1489 * that */
1490 oldcred = parent->replacement_session_keyring;
1491
1492 /* the replacement session keyring is applied just prior to userspace
1493 * restarting */
1494 parent->replacement_session_keyring = cred;
1495 cred = NULL;
1496 set_ti_thread_flag(task_thread_info(parent), TIF_NOTIFY_RESUME);
1497
1498 write_unlock_irq(&tasklist_lock);
1499 rcu_read_unlock();
1500 if (oldcred)
1501 put_cred(oldcred);
1502 return 0;
1503
1504already_same:
1505 ret = 0;
1506not_permitted:
1507 write_unlock_irq(&tasklist_lock);
1508 rcu_read_unlock();
1509 put_cred(cred);
1510 return ret;
1511
1512error_keyring:
1513 key_ref_put(keyring_r);
1514 return ret;
1515
1516#else /* !TIF_NOTIFY_RESUME */
1517 /*
1518 * To be removed when TIF_NOTIFY_RESUME has been implemented on
1519 * m68k/xtensa
1520 */
1521#warning TIF_NOTIFY_RESUME not implemented
1522 return -EOPNOTSUPP;
1523#endif /* !TIF_NOTIFY_RESUME */
1524}
1525
1526/*
1527 * The key control system call
1528 */
1529SYSCALL_DEFINE5(keyctl, int, option, unsigned long, arg2, unsigned long, arg3,
1530 unsigned long, arg4, unsigned long, arg5)
1531{
1532 switch (option) {
1533 case KEYCTL_GET_KEYRING_ID:
1534 return keyctl_get_keyring_ID((key_serial_t) arg2,
1535 (int) arg3);
1536
1537 case KEYCTL_JOIN_SESSION_KEYRING:
1538 return keyctl_join_session_keyring((const char __user *) arg2);
1539
1540 case KEYCTL_UPDATE:
1541 return keyctl_update_key((key_serial_t) arg2,
1542 (const void __user *) arg3,
1543 (size_t) arg4);
1544
1545 case KEYCTL_REVOKE:
1546 return keyctl_revoke_key((key_serial_t) arg2);
1547
1548 case KEYCTL_DESCRIBE:
1549 return keyctl_describe_key((key_serial_t) arg2,
1550 (char __user *) arg3,
1551 (unsigned) arg4);
1552
1553 case KEYCTL_CLEAR:
1554 return keyctl_keyring_clear((key_serial_t) arg2);
1555
1556 case KEYCTL_LINK:
1557 return keyctl_keyring_link((key_serial_t) arg2,
1558 (key_serial_t) arg3);
1559
1560 case KEYCTL_UNLINK:
1561 return keyctl_keyring_unlink((key_serial_t) arg2,
1562 (key_serial_t) arg3);
1563
1564 case KEYCTL_SEARCH:
1565 return keyctl_keyring_search((key_serial_t) arg2,
1566 (const char __user *) arg3,
1567 (const char __user *) arg4,
1568 (key_serial_t) arg5);
1569
1570 case KEYCTL_READ:
1571 return keyctl_read_key((key_serial_t) arg2,
1572 (char __user *) arg3,
1573 (size_t) arg4);
1574
1575 case KEYCTL_CHOWN:
1576 return keyctl_chown_key((key_serial_t) arg2,
1577 (uid_t) arg3,
1578 (gid_t) arg4);
1579
1580 case KEYCTL_SETPERM:
1581 return keyctl_setperm_key((key_serial_t) arg2,
1582 (key_perm_t) arg3);
1583
1584 case KEYCTL_INSTANTIATE:
1585 return keyctl_instantiate_key((key_serial_t) arg2,
1586 (const void __user *) arg3,
1587 (size_t) arg4,
1588 (key_serial_t) arg5);
1589
1590 case KEYCTL_NEGATE:
1591 return keyctl_negate_key((key_serial_t) arg2,
1592 (unsigned) arg3,
1593 (key_serial_t) arg4);
1594
1595 case KEYCTL_SET_REQKEY_KEYRING:
1596 return keyctl_set_reqkey_keyring(arg2);
1597
1598 case KEYCTL_SET_TIMEOUT:
1599 return keyctl_set_timeout((key_serial_t) arg2,
1600 (unsigned) arg3);
1601
1602 case KEYCTL_ASSUME_AUTHORITY:
1603 return keyctl_assume_authority((key_serial_t) arg2);
1604
1605 case KEYCTL_GET_SECURITY:
1606 return keyctl_get_security((key_serial_t) arg2,
1607 (char __user *) arg3,
1608 (size_t) arg4);
1609
1610 case KEYCTL_SESSION_TO_PARENT:
1611 return keyctl_session_to_parent();
1612
1613 case KEYCTL_REJECT:
1614 return keyctl_reject_key((key_serial_t) arg2,
1615 (unsigned) arg3,
1616 (unsigned) arg4,
1617 (key_serial_t) arg5);
1618
1619 case KEYCTL_INSTANTIATE_IOV:
1620 return keyctl_instantiate_key_iov(
1621 (key_serial_t) arg2,
1622 (const struct iovec __user *) arg3,
1623 (unsigned) arg4,
1624 (key_serial_t) arg5);
1625
1626 default:
1627 return -EOPNOTSUPP;
1628 }
1629}
1/* Userspace key control operations
2 *
3 * Copyright (C) 2004-5 Red Hat, Inc. All Rights Reserved.
4 * Written by David Howells (dhowells@redhat.com)
5 *
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public License
8 * as published by the Free Software Foundation; either version
9 * 2 of the License, or (at your option) any later version.
10 */
11
12#include <linux/module.h>
13#include <linux/init.h>
14#include <linux/sched.h>
15#include <linux/sched/task.h>
16#include <linux/slab.h>
17#include <linux/syscalls.h>
18#include <linux/key.h>
19#include <linux/keyctl.h>
20#include <linux/fs.h>
21#include <linux/capability.h>
22#include <linux/cred.h>
23#include <linux/string.h>
24#include <linux/err.h>
25#include <linux/vmalloc.h>
26#include <linux/security.h>
27#include <linux/uio.h>
28#include <linux/uaccess.h>
29#include "internal.h"
30
31#define KEY_MAX_DESC_SIZE 4096
32
33static int key_get_type_from_user(char *type,
34 const char __user *_type,
35 unsigned len)
36{
37 int ret;
38
39 ret = strncpy_from_user(type, _type, len);
40 if (ret < 0)
41 return ret;
42 if (ret == 0 || ret >= len)
43 return -EINVAL;
44 if (type[0] == '.')
45 return -EPERM;
46 type[len - 1] = '\0';
47 return 0;
48}
49
50/*
51 * Extract the description of a new key from userspace and either add it as a
52 * new key to the specified keyring or update a matching key in that keyring.
53 *
54 * If the description is NULL or an empty string, the key type is asked to
55 * generate one from the payload.
56 *
57 * The keyring must be writable so that we can attach the key to it.
58 *
59 * If successful, the new key's serial number is returned, otherwise an error
60 * code is returned.
61 */
62SYSCALL_DEFINE5(add_key, const char __user *, _type,
63 const char __user *, _description,
64 const void __user *, _payload,
65 size_t, plen,
66 key_serial_t, ringid)
67{
68 key_ref_t keyring_ref, key_ref;
69 char type[32], *description;
70 void *payload;
71 long ret;
72
73 ret = -EINVAL;
74 if (plen > 1024 * 1024 - 1)
75 goto error;
76
77 /* draw all the data into kernel space */
78 ret = key_get_type_from_user(type, _type, sizeof(type));
79 if (ret < 0)
80 goto error;
81
82 description = NULL;
83 if (_description) {
84 description = strndup_user(_description, KEY_MAX_DESC_SIZE);
85 if (IS_ERR(description)) {
86 ret = PTR_ERR(description);
87 goto error;
88 }
89 if (!*description) {
90 kfree(description);
91 description = NULL;
92 } else if ((description[0] == '.') &&
93 (strncmp(type, "keyring", 7) == 0)) {
94 ret = -EPERM;
95 goto error2;
96 }
97 }
98
99 /* pull the payload in if one was supplied */
100 payload = NULL;
101
102 if (plen) {
103 ret = -ENOMEM;
104 payload = kvmalloc(plen, GFP_KERNEL);
105 if (!payload)
106 goto error2;
107
108 ret = -EFAULT;
109 if (copy_from_user(payload, _payload, plen) != 0)
110 goto error3;
111 }
112
113 /* find the target keyring (which must be writable) */
114 keyring_ref = lookup_user_key(ringid, KEY_LOOKUP_CREATE, KEY_NEED_WRITE);
115 if (IS_ERR(keyring_ref)) {
116 ret = PTR_ERR(keyring_ref);
117 goto error3;
118 }
119
120 /* create or update the requested key and add it to the target
121 * keyring */
122 key_ref = key_create_or_update(keyring_ref, type, description,
123 payload, plen, KEY_PERM_UNDEF,
124 KEY_ALLOC_IN_QUOTA);
125 if (!IS_ERR(key_ref)) {
126 ret = key_ref_to_ptr(key_ref)->serial;
127 key_ref_put(key_ref);
128 }
129 else {
130 ret = PTR_ERR(key_ref);
131 }
132
133 key_ref_put(keyring_ref);
134 error3:
135 if (payload) {
136 memzero_explicit(payload, plen);
137 kvfree(payload);
138 }
139 error2:
140 kfree(description);
141 error:
142 return ret;
143}
144
145/*
146 * Search the process keyrings and keyring trees linked from those for a
147 * matching key. Keyrings must have appropriate Search permission to be
148 * searched.
149 *
150 * If a key is found, it will be attached to the destination keyring if there's
151 * one specified and the serial number of the key will be returned.
152 *
153 * If no key is found, /sbin/request-key will be invoked if _callout_info is
154 * non-NULL in an attempt to create a key. The _callout_info string will be
155 * passed to /sbin/request-key to aid with completing the request. If the
156 * _callout_info string is "" then it will be changed to "-".
157 */
158SYSCALL_DEFINE4(request_key, const char __user *, _type,
159 const char __user *, _description,
160 const char __user *, _callout_info,
161 key_serial_t, destringid)
162{
163 struct key_type *ktype;
164 struct key *key;
165 key_ref_t dest_ref;
166 size_t callout_len;
167 char type[32], *description, *callout_info;
168 long ret;
169
170 /* pull the type into kernel space */
171 ret = key_get_type_from_user(type, _type, sizeof(type));
172 if (ret < 0)
173 goto error;
174
175 /* pull the description into kernel space */
176 description = strndup_user(_description, KEY_MAX_DESC_SIZE);
177 if (IS_ERR(description)) {
178 ret = PTR_ERR(description);
179 goto error;
180 }
181
182 /* pull the callout info into kernel space */
183 callout_info = NULL;
184 callout_len = 0;
185 if (_callout_info) {
186 callout_info = strndup_user(_callout_info, PAGE_SIZE);
187 if (IS_ERR(callout_info)) {
188 ret = PTR_ERR(callout_info);
189 goto error2;
190 }
191 callout_len = strlen(callout_info);
192 }
193
194 /* get the destination keyring if specified */
195 dest_ref = NULL;
196 if (destringid) {
197 dest_ref = lookup_user_key(destringid, KEY_LOOKUP_CREATE,
198 KEY_NEED_WRITE);
199 if (IS_ERR(dest_ref)) {
200 ret = PTR_ERR(dest_ref);
201 goto error3;
202 }
203 }
204
205 /* find the key type */
206 ktype = key_type_lookup(type);
207 if (IS_ERR(ktype)) {
208 ret = PTR_ERR(ktype);
209 goto error4;
210 }
211
212 /* do the search */
213 key = request_key_and_link(ktype, description, callout_info,
214 callout_len, NULL, key_ref_to_ptr(dest_ref),
215 KEY_ALLOC_IN_QUOTA);
216 if (IS_ERR(key)) {
217 ret = PTR_ERR(key);
218 goto error5;
219 }
220
221 /* wait for the key to finish being constructed */
222 ret = wait_for_key_construction(key, 1);
223 if (ret < 0)
224 goto error6;
225
226 ret = key->serial;
227
228error6:
229 key_put(key);
230error5:
231 key_type_put(ktype);
232error4:
233 key_ref_put(dest_ref);
234error3:
235 kfree(callout_info);
236error2:
237 kfree(description);
238error:
239 return ret;
240}
241
242/*
243 * Get the ID of the specified process keyring.
244 *
245 * The requested keyring must have search permission to be found.
246 *
247 * If successful, the ID of the requested keyring will be returned.
248 */
249long keyctl_get_keyring_ID(key_serial_t id, int create)
250{
251 key_ref_t key_ref;
252 unsigned long lflags;
253 long ret;
254
255 lflags = create ? KEY_LOOKUP_CREATE : 0;
256 key_ref = lookup_user_key(id, lflags, KEY_NEED_SEARCH);
257 if (IS_ERR(key_ref)) {
258 ret = PTR_ERR(key_ref);
259 goto error;
260 }
261
262 ret = key_ref_to_ptr(key_ref)->serial;
263 key_ref_put(key_ref);
264error:
265 return ret;
266}
267
268/*
269 * Join a (named) session keyring.
270 *
271 * Create and join an anonymous session keyring or join a named session
272 * keyring, creating it if necessary. A named session keyring must have Search
273 * permission for it to be joined. Session keyrings without this permit will
274 * be skipped over. It is not permitted for userspace to create or join
275 * keyrings whose name begin with a dot.
276 *
277 * If successful, the ID of the joined session keyring will be returned.
278 */
279long keyctl_join_session_keyring(const char __user *_name)
280{
281 char *name;
282 long ret;
283
284 /* fetch the name from userspace */
285 name = NULL;
286 if (_name) {
287 name = strndup_user(_name, KEY_MAX_DESC_SIZE);
288 if (IS_ERR(name)) {
289 ret = PTR_ERR(name);
290 goto error;
291 }
292
293 ret = -EPERM;
294 if (name[0] == '.')
295 goto error_name;
296 }
297
298 /* join the session */
299 ret = join_session_keyring(name);
300error_name:
301 kfree(name);
302error:
303 return ret;
304}
305
306/*
307 * Update a key's data payload from the given data.
308 *
309 * The key must grant the caller Write permission and the key type must support
310 * updating for this to work. A negative key can be positively instantiated
311 * with this call.
312 *
313 * If successful, 0 will be returned. If the key type does not support
314 * updating, then -EOPNOTSUPP will be returned.
315 */
316long keyctl_update_key(key_serial_t id,
317 const void __user *_payload,
318 size_t plen)
319{
320 key_ref_t key_ref;
321 void *payload;
322 long ret;
323
324 ret = -EINVAL;
325 if (plen > PAGE_SIZE)
326 goto error;
327
328 /* pull the payload in if one was supplied */
329 payload = NULL;
330 if (plen) {
331 ret = -ENOMEM;
332 payload = kmalloc(plen, GFP_KERNEL);
333 if (!payload)
334 goto error;
335
336 ret = -EFAULT;
337 if (copy_from_user(payload, _payload, plen) != 0)
338 goto error2;
339 }
340
341 /* find the target key (which must be writable) */
342 key_ref = lookup_user_key(id, 0, KEY_NEED_WRITE);
343 if (IS_ERR(key_ref)) {
344 ret = PTR_ERR(key_ref);
345 goto error2;
346 }
347
348 /* update the key */
349 ret = key_update(key_ref, payload, plen);
350
351 key_ref_put(key_ref);
352error2:
353 kzfree(payload);
354error:
355 return ret;
356}
357
358/*
359 * Revoke a key.
360 *
361 * The key must be grant the caller Write or Setattr permission for this to
362 * work. The key type should give up its quota claim when revoked. The key
363 * and any links to the key will be automatically garbage collected after a
364 * certain amount of time (/proc/sys/kernel/keys/gc_delay).
365 *
366 * Keys with KEY_FLAG_KEEP set should not be revoked.
367 *
368 * If successful, 0 is returned.
369 */
370long keyctl_revoke_key(key_serial_t id)
371{
372 key_ref_t key_ref;
373 struct key *key;
374 long ret;
375
376 key_ref = lookup_user_key(id, 0, KEY_NEED_WRITE);
377 if (IS_ERR(key_ref)) {
378 ret = PTR_ERR(key_ref);
379 if (ret != -EACCES)
380 goto error;
381 key_ref = lookup_user_key(id, 0, KEY_NEED_SETATTR);
382 if (IS_ERR(key_ref)) {
383 ret = PTR_ERR(key_ref);
384 goto error;
385 }
386 }
387
388 key = key_ref_to_ptr(key_ref);
389 ret = 0;
390 if (test_bit(KEY_FLAG_KEEP, &key->flags))
391 ret = -EPERM;
392 else
393 key_revoke(key);
394
395 key_ref_put(key_ref);
396error:
397 return ret;
398}
399
400/*
401 * Invalidate a key.
402 *
403 * The key must be grant the caller Invalidate permission for this to work.
404 * The key and any links to the key will be automatically garbage collected
405 * immediately.
406 *
407 * Keys with KEY_FLAG_KEEP set should not be invalidated.
408 *
409 * If successful, 0 is returned.
410 */
411long keyctl_invalidate_key(key_serial_t id)
412{
413 key_ref_t key_ref;
414 struct key *key;
415 long ret;
416
417 kenter("%d", id);
418
419 key_ref = lookup_user_key(id, 0, KEY_NEED_SEARCH);
420 if (IS_ERR(key_ref)) {
421 ret = PTR_ERR(key_ref);
422
423 /* Root is permitted to invalidate certain special keys */
424 if (capable(CAP_SYS_ADMIN)) {
425 key_ref = lookup_user_key(id, 0, 0);
426 if (IS_ERR(key_ref))
427 goto error;
428 if (test_bit(KEY_FLAG_ROOT_CAN_INVAL,
429 &key_ref_to_ptr(key_ref)->flags))
430 goto invalidate;
431 goto error_put;
432 }
433
434 goto error;
435 }
436
437invalidate:
438 key = key_ref_to_ptr(key_ref);
439 ret = 0;
440 if (test_bit(KEY_FLAG_KEEP, &key->flags))
441 ret = -EPERM;
442 else
443 key_invalidate(key);
444error_put:
445 key_ref_put(key_ref);
446error:
447 kleave(" = %ld", ret);
448 return ret;
449}
450
451/*
452 * Clear the specified keyring, creating an empty process keyring if one of the
453 * special keyring IDs is used.
454 *
455 * The keyring must grant the caller Write permission and not have
456 * KEY_FLAG_KEEP set for this to work. If successful, 0 will be returned.
457 */
458long keyctl_keyring_clear(key_serial_t ringid)
459{
460 key_ref_t keyring_ref;
461 struct key *keyring;
462 long ret;
463
464 keyring_ref = lookup_user_key(ringid, KEY_LOOKUP_CREATE, KEY_NEED_WRITE);
465 if (IS_ERR(keyring_ref)) {
466 ret = PTR_ERR(keyring_ref);
467
468 /* Root is permitted to invalidate certain special keyrings */
469 if (capable(CAP_SYS_ADMIN)) {
470 keyring_ref = lookup_user_key(ringid, 0, 0);
471 if (IS_ERR(keyring_ref))
472 goto error;
473 if (test_bit(KEY_FLAG_ROOT_CAN_CLEAR,
474 &key_ref_to_ptr(keyring_ref)->flags))
475 goto clear;
476 goto error_put;
477 }
478
479 goto error;
480 }
481
482clear:
483 keyring = key_ref_to_ptr(keyring_ref);
484 if (test_bit(KEY_FLAG_KEEP, &keyring->flags))
485 ret = -EPERM;
486 else
487 ret = keyring_clear(keyring);
488error_put:
489 key_ref_put(keyring_ref);
490error:
491 return ret;
492}
493
494/*
495 * Create a link from a keyring to a key if there's no matching key in the
496 * keyring, otherwise replace the link to the matching key with a link to the
497 * new key.
498 *
499 * The key must grant the caller Link permission and the the keyring must grant
500 * the caller Write permission. Furthermore, if an additional link is created,
501 * the keyring's quota will be extended.
502 *
503 * If successful, 0 will be returned.
504 */
505long keyctl_keyring_link(key_serial_t id, key_serial_t ringid)
506{
507 key_ref_t keyring_ref, key_ref;
508 long ret;
509
510 keyring_ref = lookup_user_key(ringid, KEY_LOOKUP_CREATE, KEY_NEED_WRITE);
511 if (IS_ERR(keyring_ref)) {
512 ret = PTR_ERR(keyring_ref);
513 goto error;
514 }
515
516 key_ref = lookup_user_key(id, KEY_LOOKUP_CREATE, KEY_NEED_LINK);
517 if (IS_ERR(key_ref)) {
518 ret = PTR_ERR(key_ref);
519 goto error2;
520 }
521
522 ret = key_link(key_ref_to_ptr(keyring_ref), key_ref_to_ptr(key_ref));
523
524 key_ref_put(key_ref);
525error2:
526 key_ref_put(keyring_ref);
527error:
528 return ret;
529}
530
531/*
532 * Unlink a key from a keyring.
533 *
534 * The keyring must grant the caller Write permission for this to work; the key
535 * itself need not grant the caller anything. If the last link to a key is
536 * removed then that key will be scheduled for destruction.
537 *
538 * Keys or keyrings with KEY_FLAG_KEEP set should not be unlinked.
539 *
540 * If successful, 0 will be returned.
541 */
542long keyctl_keyring_unlink(key_serial_t id, key_serial_t ringid)
543{
544 key_ref_t keyring_ref, key_ref;
545 struct key *keyring, *key;
546 long ret;
547
548 keyring_ref = lookup_user_key(ringid, 0, KEY_NEED_WRITE);
549 if (IS_ERR(keyring_ref)) {
550 ret = PTR_ERR(keyring_ref);
551 goto error;
552 }
553
554 key_ref = lookup_user_key(id, KEY_LOOKUP_FOR_UNLINK, 0);
555 if (IS_ERR(key_ref)) {
556 ret = PTR_ERR(key_ref);
557 goto error2;
558 }
559
560 keyring = key_ref_to_ptr(keyring_ref);
561 key = key_ref_to_ptr(key_ref);
562 if (test_bit(KEY_FLAG_KEEP, &keyring->flags) &&
563 test_bit(KEY_FLAG_KEEP, &key->flags))
564 ret = -EPERM;
565 else
566 ret = key_unlink(keyring, key);
567
568 key_ref_put(key_ref);
569error2:
570 key_ref_put(keyring_ref);
571error:
572 return ret;
573}
574
575/*
576 * Return a description of a key to userspace.
577 *
578 * The key must grant the caller View permission for this to work.
579 *
580 * If there's a buffer, we place up to buflen bytes of data into it formatted
581 * in the following way:
582 *
583 * type;uid;gid;perm;description<NUL>
584 *
585 * If successful, we return the amount of description available, irrespective
586 * of how much we may have copied into the buffer.
587 */
588long keyctl_describe_key(key_serial_t keyid,
589 char __user *buffer,
590 size_t buflen)
591{
592 struct key *key, *instkey;
593 key_ref_t key_ref;
594 char *infobuf;
595 long ret;
596 int desclen, infolen;
597
598 key_ref = lookup_user_key(keyid, KEY_LOOKUP_PARTIAL, KEY_NEED_VIEW);
599 if (IS_ERR(key_ref)) {
600 /* viewing a key under construction is permitted if we have the
601 * authorisation token handy */
602 if (PTR_ERR(key_ref) == -EACCES) {
603 instkey = key_get_instantiation_authkey(keyid);
604 if (!IS_ERR(instkey)) {
605 key_put(instkey);
606 key_ref = lookup_user_key(keyid,
607 KEY_LOOKUP_PARTIAL,
608 0);
609 if (!IS_ERR(key_ref))
610 goto okay;
611 }
612 }
613
614 ret = PTR_ERR(key_ref);
615 goto error;
616 }
617
618okay:
619 key = key_ref_to_ptr(key_ref);
620 desclen = strlen(key->description);
621
622 /* calculate how much information we're going to return */
623 ret = -ENOMEM;
624 infobuf = kasprintf(GFP_KERNEL,
625 "%s;%d;%d;%08x;",
626 key->type->name,
627 from_kuid_munged(current_user_ns(), key->uid),
628 from_kgid_munged(current_user_ns(), key->gid),
629 key->perm);
630 if (!infobuf)
631 goto error2;
632 infolen = strlen(infobuf);
633 ret = infolen + desclen + 1;
634
635 /* consider returning the data */
636 if (buffer && buflen >= ret) {
637 if (copy_to_user(buffer, infobuf, infolen) != 0 ||
638 copy_to_user(buffer + infolen, key->description,
639 desclen + 1) != 0)
640 ret = -EFAULT;
641 }
642
643 kfree(infobuf);
644error2:
645 key_ref_put(key_ref);
646error:
647 return ret;
648}
649
650/*
651 * Search the specified keyring and any keyrings it links to for a matching
652 * key. Only keyrings that grant the caller Search permission will be searched
653 * (this includes the starting keyring). Only keys with Search permission can
654 * be found.
655 *
656 * If successful, the found key will be linked to the destination keyring if
657 * supplied and the key has Link permission, and the found key ID will be
658 * returned.
659 */
660long keyctl_keyring_search(key_serial_t ringid,
661 const char __user *_type,
662 const char __user *_description,
663 key_serial_t destringid)
664{
665 struct key_type *ktype;
666 key_ref_t keyring_ref, key_ref, dest_ref;
667 char type[32], *description;
668 long ret;
669
670 /* pull the type and description into kernel space */
671 ret = key_get_type_from_user(type, _type, sizeof(type));
672 if (ret < 0)
673 goto error;
674
675 description = strndup_user(_description, KEY_MAX_DESC_SIZE);
676 if (IS_ERR(description)) {
677 ret = PTR_ERR(description);
678 goto error;
679 }
680
681 /* get the keyring at which to begin the search */
682 keyring_ref = lookup_user_key(ringid, 0, KEY_NEED_SEARCH);
683 if (IS_ERR(keyring_ref)) {
684 ret = PTR_ERR(keyring_ref);
685 goto error2;
686 }
687
688 /* get the destination keyring if specified */
689 dest_ref = NULL;
690 if (destringid) {
691 dest_ref = lookup_user_key(destringid, KEY_LOOKUP_CREATE,
692 KEY_NEED_WRITE);
693 if (IS_ERR(dest_ref)) {
694 ret = PTR_ERR(dest_ref);
695 goto error3;
696 }
697 }
698
699 /* find the key type */
700 ktype = key_type_lookup(type);
701 if (IS_ERR(ktype)) {
702 ret = PTR_ERR(ktype);
703 goto error4;
704 }
705
706 /* do the search */
707 key_ref = keyring_search(keyring_ref, ktype, description);
708 if (IS_ERR(key_ref)) {
709 ret = PTR_ERR(key_ref);
710
711 /* treat lack or presence of a negative key the same */
712 if (ret == -EAGAIN)
713 ret = -ENOKEY;
714 goto error5;
715 }
716
717 /* link the resulting key to the destination keyring if we can */
718 if (dest_ref) {
719 ret = key_permission(key_ref, KEY_NEED_LINK);
720 if (ret < 0)
721 goto error6;
722
723 ret = key_link(key_ref_to_ptr(dest_ref), key_ref_to_ptr(key_ref));
724 if (ret < 0)
725 goto error6;
726 }
727
728 ret = key_ref_to_ptr(key_ref)->serial;
729
730error6:
731 key_ref_put(key_ref);
732error5:
733 key_type_put(ktype);
734error4:
735 key_ref_put(dest_ref);
736error3:
737 key_ref_put(keyring_ref);
738error2:
739 kfree(description);
740error:
741 return ret;
742}
743
744/*
745 * Read a key's payload.
746 *
747 * The key must either grant the caller Read permission, or it must grant the
748 * caller Search permission when searched for from the process keyrings.
749 *
750 * If successful, we place up to buflen bytes of data into the buffer, if one
751 * is provided, and return the amount of data that is available in the key,
752 * irrespective of how much we copied into the buffer.
753 */
754long keyctl_read_key(key_serial_t keyid, char __user *buffer, size_t buflen)
755{
756 struct key *key;
757 key_ref_t key_ref;
758 long ret;
759
760 /* find the key first */
761 key_ref = lookup_user_key(keyid, 0, 0);
762 if (IS_ERR(key_ref)) {
763 ret = -ENOKEY;
764 goto error;
765 }
766
767 key = key_ref_to_ptr(key_ref);
768
769 ret = key_read_state(key);
770 if (ret < 0)
771 goto error2; /* Negatively instantiated */
772
773 /* see if we can read it directly */
774 ret = key_permission(key_ref, KEY_NEED_READ);
775 if (ret == 0)
776 goto can_read_key;
777 if (ret != -EACCES)
778 goto error2;
779
780 /* we can't; see if it's searchable from this process's keyrings
781 * - we automatically take account of the fact that it may be
782 * dangling off an instantiation key
783 */
784 if (!is_key_possessed(key_ref)) {
785 ret = -EACCES;
786 goto error2;
787 }
788
789 /* the key is probably readable - now try to read it */
790can_read_key:
791 ret = -EOPNOTSUPP;
792 if (key->type->read) {
793 /* Read the data with the semaphore held (since we might sleep)
794 * to protect against the key being updated or revoked.
795 */
796 down_read(&key->sem);
797 ret = key_validate(key);
798 if (ret == 0)
799 ret = key->type->read(key, buffer, buflen);
800 up_read(&key->sem);
801 }
802
803error2:
804 key_put(key);
805error:
806 return ret;
807}
808
809/*
810 * Change the ownership of a key
811 *
812 * The key must grant the caller Setattr permission for this to work, though
813 * the key need not be fully instantiated yet. For the UID to be changed, or
814 * for the GID to be changed to a group the caller is not a member of, the
815 * caller must have sysadmin capability. If either uid or gid is -1 then that
816 * attribute is not changed.
817 *
818 * If the UID is to be changed, the new user must have sufficient quota to
819 * accept the key. The quota deduction will be removed from the old user to
820 * the new user should the attribute be changed.
821 *
822 * If successful, 0 will be returned.
823 */
824long keyctl_chown_key(key_serial_t id, uid_t user, gid_t group)
825{
826 struct key_user *newowner, *zapowner = NULL;
827 struct key *key;
828 key_ref_t key_ref;
829 long ret;
830 kuid_t uid;
831 kgid_t gid;
832
833 uid = make_kuid(current_user_ns(), user);
834 gid = make_kgid(current_user_ns(), group);
835 ret = -EINVAL;
836 if ((user != (uid_t) -1) && !uid_valid(uid))
837 goto error;
838 if ((group != (gid_t) -1) && !gid_valid(gid))
839 goto error;
840
841 ret = 0;
842 if (user == (uid_t) -1 && group == (gid_t) -1)
843 goto error;
844
845 key_ref = lookup_user_key(id, KEY_LOOKUP_CREATE | KEY_LOOKUP_PARTIAL,
846 KEY_NEED_SETATTR);
847 if (IS_ERR(key_ref)) {
848 ret = PTR_ERR(key_ref);
849 goto error;
850 }
851
852 key = key_ref_to_ptr(key_ref);
853
854 /* make the changes with the locks held to prevent chown/chown races */
855 ret = -EACCES;
856 down_write(&key->sem);
857
858 if (!capable(CAP_SYS_ADMIN)) {
859 /* only the sysadmin can chown a key to some other UID */
860 if (user != (uid_t) -1 && !uid_eq(key->uid, uid))
861 goto error_put;
862
863 /* only the sysadmin can set the key's GID to a group other
864 * than one of those that the current process subscribes to */
865 if (group != (gid_t) -1 && !gid_eq(gid, key->gid) && !in_group_p(gid))
866 goto error_put;
867 }
868
869 /* change the UID */
870 if (user != (uid_t) -1 && !uid_eq(uid, key->uid)) {
871 ret = -ENOMEM;
872 newowner = key_user_lookup(uid);
873 if (!newowner)
874 goto error_put;
875
876 /* transfer the quota burden to the new user */
877 if (test_bit(KEY_FLAG_IN_QUOTA, &key->flags)) {
878 unsigned maxkeys = uid_eq(uid, GLOBAL_ROOT_UID) ?
879 key_quota_root_maxkeys : key_quota_maxkeys;
880 unsigned maxbytes = uid_eq(uid, GLOBAL_ROOT_UID) ?
881 key_quota_root_maxbytes : key_quota_maxbytes;
882
883 spin_lock(&newowner->lock);
884 if (newowner->qnkeys + 1 >= maxkeys ||
885 newowner->qnbytes + key->quotalen >= maxbytes ||
886 newowner->qnbytes + key->quotalen <
887 newowner->qnbytes)
888 goto quota_overrun;
889
890 newowner->qnkeys++;
891 newowner->qnbytes += key->quotalen;
892 spin_unlock(&newowner->lock);
893
894 spin_lock(&key->user->lock);
895 key->user->qnkeys--;
896 key->user->qnbytes -= key->quotalen;
897 spin_unlock(&key->user->lock);
898 }
899
900 atomic_dec(&key->user->nkeys);
901 atomic_inc(&newowner->nkeys);
902
903 if (key->state != KEY_IS_UNINSTANTIATED) {
904 atomic_dec(&key->user->nikeys);
905 atomic_inc(&newowner->nikeys);
906 }
907
908 zapowner = key->user;
909 key->user = newowner;
910 key->uid = uid;
911 }
912
913 /* change the GID */
914 if (group != (gid_t) -1)
915 key->gid = gid;
916
917 ret = 0;
918
919error_put:
920 up_write(&key->sem);
921 key_put(key);
922 if (zapowner)
923 key_user_put(zapowner);
924error:
925 return ret;
926
927quota_overrun:
928 spin_unlock(&newowner->lock);
929 zapowner = newowner;
930 ret = -EDQUOT;
931 goto error_put;
932}
933
934/*
935 * Change the permission mask on a key.
936 *
937 * The key must grant the caller Setattr permission for this to work, though
938 * the key need not be fully instantiated yet. If the caller does not have
939 * sysadmin capability, it may only change the permission on keys that it owns.
940 */
941long keyctl_setperm_key(key_serial_t id, key_perm_t perm)
942{
943 struct key *key;
944 key_ref_t key_ref;
945 long ret;
946
947 ret = -EINVAL;
948 if (perm & ~(KEY_POS_ALL | KEY_USR_ALL | KEY_GRP_ALL | KEY_OTH_ALL))
949 goto error;
950
951 key_ref = lookup_user_key(id, KEY_LOOKUP_CREATE | KEY_LOOKUP_PARTIAL,
952 KEY_NEED_SETATTR);
953 if (IS_ERR(key_ref)) {
954 ret = PTR_ERR(key_ref);
955 goto error;
956 }
957
958 key = key_ref_to_ptr(key_ref);
959
960 /* make the changes with the locks held to prevent chown/chmod races */
961 ret = -EACCES;
962 down_write(&key->sem);
963
964 /* if we're not the sysadmin, we can only change a key that we own */
965 if (capable(CAP_SYS_ADMIN) || uid_eq(key->uid, current_fsuid())) {
966 key->perm = perm;
967 ret = 0;
968 }
969
970 up_write(&key->sem);
971 key_put(key);
972error:
973 return ret;
974}
975
976/*
977 * Get the destination keyring for instantiation and check that the caller has
978 * Write permission on it.
979 */
980static long get_instantiation_keyring(key_serial_t ringid,
981 struct request_key_auth *rka,
982 struct key **_dest_keyring)
983{
984 key_ref_t dkref;
985
986 *_dest_keyring = NULL;
987
988 /* just return a NULL pointer if we weren't asked to make a link */
989 if (ringid == 0)
990 return 0;
991
992 /* if a specific keyring is nominated by ID, then use that */
993 if (ringid > 0) {
994 dkref = lookup_user_key(ringid, KEY_LOOKUP_CREATE, KEY_NEED_WRITE);
995 if (IS_ERR(dkref))
996 return PTR_ERR(dkref);
997 *_dest_keyring = key_ref_to_ptr(dkref);
998 return 0;
999 }
1000
1001 if (ringid == KEY_SPEC_REQKEY_AUTH_KEY)
1002 return -EINVAL;
1003
1004 /* otherwise specify the destination keyring recorded in the
1005 * authorisation key (any KEY_SPEC_*_KEYRING) */
1006 if (ringid >= KEY_SPEC_REQUESTOR_KEYRING) {
1007 *_dest_keyring = key_get(rka->dest_keyring);
1008 return 0;
1009 }
1010
1011 return -ENOKEY;
1012}
1013
1014/*
1015 * Change the request_key authorisation key on the current process.
1016 */
1017static int keyctl_change_reqkey_auth(struct key *key)
1018{
1019 struct cred *new;
1020
1021 new = prepare_creds();
1022 if (!new)
1023 return -ENOMEM;
1024
1025 key_put(new->request_key_auth);
1026 new->request_key_auth = key_get(key);
1027
1028 return commit_creds(new);
1029}
1030
1031/*
1032 * Instantiate a key with the specified payload and link the key into the
1033 * destination keyring if one is given.
1034 *
1035 * The caller must have the appropriate instantiation permit set for this to
1036 * work (see keyctl_assume_authority). No other permissions are required.
1037 *
1038 * If successful, 0 will be returned.
1039 */
1040long keyctl_instantiate_key_common(key_serial_t id,
1041 struct iov_iter *from,
1042 key_serial_t ringid)
1043{
1044 const struct cred *cred = current_cred();
1045 struct request_key_auth *rka;
1046 struct key *instkey, *dest_keyring;
1047 size_t plen = from ? iov_iter_count(from) : 0;
1048 void *payload;
1049 long ret;
1050
1051 kenter("%d,,%zu,%d", id, plen, ringid);
1052
1053 if (!plen)
1054 from = NULL;
1055
1056 ret = -EINVAL;
1057 if (plen > 1024 * 1024 - 1)
1058 goto error;
1059
1060 /* the appropriate instantiation authorisation key must have been
1061 * assumed before calling this */
1062 ret = -EPERM;
1063 instkey = cred->request_key_auth;
1064 if (!instkey)
1065 goto error;
1066
1067 rka = instkey->payload.data[0];
1068 if (rka->target_key->serial != id)
1069 goto error;
1070
1071 /* pull the payload in if one was supplied */
1072 payload = NULL;
1073
1074 if (from) {
1075 ret = -ENOMEM;
1076 payload = kvmalloc(plen, GFP_KERNEL);
1077 if (!payload)
1078 goto error;
1079
1080 ret = -EFAULT;
1081 if (!copy_from_iter_full(payload, plen, from))
1082 goto error2;
1083 }
1084
1085 /* find the destination keyring amongst those belonging to the
1086 * requesting task */
1087 ret = get_instantiation_keyring(ringid, rka, &dest_keyring);
1088 if (ret < 0)
1089 goto error2;
1090
1091 /* instantiate the key and link it into a keyring */
1092 ret = key_instantiate_and_link(rka->target_key, payload, plen,
1093 dest_keyring, instkey);
1094
1095 key_put(dest_keyring);
1096
1097 /* discard the assumed authority if it's just been disabled by
1098 * instantiation of the key */
1099 if (ret == 0)
1100 keyctl_change_reqkey_auth(NULL);
1101
1102error2:
1103 if (payload) {
1104 memzero_explicit(payload, plen);
1105 kvfree(payload);
1106 }
1107error:
1108 return ret;
1109}
1110
1111/*
1112 * Instantiate a key with the specified payload and link the key into the
1113 * destination keyring if one is given.
1114 *
1115 * The caller must have the appropriate instantiation permit set for this to
1116 * work (see keyctl_assume_authority). No other permissions are required.
1117 *
1118 * If successful, 0 will be returned.
1119 */
1120long keyctl_instantiate_key(key_serial_t id,
1121 const void __user *_payload,
1122 size_t plen,
1123 key_serial_t ringid)
1124{
1125 if (_payload && plen) {
1126 struct iovec iov;
1127 struct iov_iter from;
1128 int ret;
1129
1130 ret = import_single_range(WRITE, (void __user *)_payload, plen,
1131 &iov, &from);
1132 if (unlikely(ret))
1133 return ret;
1134
1135 return keyctl_instantiate_key_common(id, &from, ringid);
1136 }
1137
1138 return keyctl_instantiate_key_common(id, NULL, ringid);
1139}
1140
1141/*
1142 * Instantiate a key with the specified multipart payload and link the key into
1143 * the destination keyring if one is given.
1144 *
1145 * The caller must have the appropriate instantiation permit set for this to
1146 * work (see keyctl_assume_authority). No other permissions are required.
1147 *
1148 * If successful, 0 will be returned.
1149 */
1150long keyctl_instantiate_key_iov(key_serial_t id,
1151 const struct iovec __user *_payload_iov,
1152 unsigned ioc,
1153 key_serial_t ringid)
1154{
1155 struct iovec iovstack[UIO_FASTIOV], *iov = iovstack;
1156 struct iov_iter from;
1157 long ret;
1158
1159 if (!_payload_iov)
1160 ioc = 0;
1161
1162 ret = import_iovec(WRITE, _payload_iov, ioc,
1163 ARRAY_SIZE(iovstack), &iov, &from);
1164 if (ret < 0)
1165 return ret;
1166 ret = keyctl_instantiate_key_common(id, &from, ringid);
1167 kfree(iov);
1168 return ret;
1169}
1170
1171/*
1172 * Negatively instantiate the key with the given timeout (in seconds) and link
1173 * the key into the destination keyring if one is given.
1174 *
1175 * The caller must have the appropriate instantiation permit set for this to
1176 * work (see keyctl_assume_authority). No other permissions are required.
1177 *
1178 * The key and any links to the key will be automatically garbage collected
1179 * after the timeout expires.
1180 *
1181 * Negative keys are used to rate limit repeated request_key() calls by causing
1182 * them to return -ENOKEY until the negative key expires.
1183 *
1184 * If successful, 0 will be returned.
1185 */
1186long keyctl_negate_key(key_serial_t id, unsigned timeout, key_serial_t ringid)
1187{
1188 return keyctl_reject_key(id, timeout, ENOKEY, ringid);
1189}
1190
1191/*
1192 * Negatively instantiate the key with the given timeout (in seconds) and error
1193 * code and link the key into the destination keyring if one is given.
1194 *
1195 * The caller must have the appropriate instantiation permit set for this to
1196 * work (see keyctl_assume_authority). No other permissions are required.
1197 *
1198 * The key and any links to the key will be automatically garbage collected
1199 * after the timeout expires.
1200 *
1201 * Negative keys are used to rate limit repeated request_key() calls by causing
1202 * them to return the specified error code until the negative key expires.
1203 *
1204 * If successful, 0 will be returned.
1205 */
1206long keyctl_reject_key(key_serial_t id, unsigned timeout, unsigned error,
1207 key_serial_t ringid)
1208{
1209 const struct cred *cred = current_cred();
1210 struct request_key_auth *rka;
1211 struct key *instkey, *dest_keyring;
1212 long ret;
1213
1214 kenter("%d,%u,%u,%d", id, timeout, error, ringid);
1215
1216 /* must be a valid error code and mustn't be a kernel special */
1217 if (error <= 0 ||
1218 error >= MAX_ERRNO ||
1219 error == ERESTARTSYS ||
1220 error == ERESTARTNOINTR ||
1221 error == ERESTARTNOHAND ||
1222 error == ERESTART_RESTARTBLOCK)
1223 return -EINVAL;
1224
1225 /* the appropriate instantiation authorisation key must have been
1226 * assumed before calling this */
1227 ret = -EPERM;
1228 instkey = cred->request_key_auth;
1229 if (!instkey)
1230 goto error;
1231
1232 rka = instkey->payload.data[0];
1233 if (rka->target_key->serial != id)
1234 goto error;
1235
1236 /* find the destination keyring if present (which must also be
1237 * writable) */
1238 ret = get_instantiation_keyring(ringid, rka, &dest_keyring);
1239 if (ret < 0)
1240 goto error;
1241
1242 /* instantiate the key and link it into a keyring */
1243 ret = key_reject_and_link(rka->target_key, timeout, error,
1244 dest_keyring, instkey);
1245
1246 key_put(dest_keyring);
1247
1248 /* discard the assumed authority if it's just been disabled by
1249 * instantiation of the key */
1250 if (ret == 0)
1251 keyctl_change_reqkey_auth(NULL);
1252
1253error:
1254 return ret;
1255}
1256
1257/*
1258 * Read or set the default keyring in which request_key() will cache keys and
1259 * return the old setting.
1260 *
1261 * If a thread or process keyring is specified then it will be created if it
1262 * doesn't yet exist. The old setting will be returned if successful.
1263 */
1264long keyctl_set_reqkey_keyring(int reqkey_defl)
1265{
1266 struct cred *new;
1267 int ret, old_setting;
1268
1269 old_setting = current_cred_xxx(jit_keyring);
1270
1271 if (reqkey_defl == KEY_REQKEY_DEFL_NO_CHANGE)
1272 return old_setting;
1273
1274 new = prepare_creds();
1275 if (!new)
1276 return -ENOMEM;
1277
1278 switch (reqkey_defl) {
1279 case KEY_REQKEY_DEFL_THREAD_KEYRING:
1280 ret = install_thread_keyring_to_cred(new);
1281 if (ret < 0)
1282 goto error;
1283 goto set;
1284
1285 case KEY_REQKEY_DEFL_PROCESS_KEYRING:
1286 ret = install_process_keyring_to_cred(new);
1287 if (ret < 0)
1288 goto error;
1289 goto set;
1290
1291 case KEY_REQKEY_DEFL_DEFAULT:
1292 case KEY_REQKEY_DEFL_SESSION_KEYRING:
1293 case KEY_REQKEY_DEFL_USER_KEYRING:
1294 case KEY_REQKEY_DEFL_USER_SESSION_KEYRING:
1295 case KEY_REQKEY_DEFL_REQUESTOR_KEYRING:
1296 goto set;
1297
1298 case KEY_REQKEY_DEFL_NO_CHANGE:
1299 case KEY_REQKEY_DEFL_GROUP_KEYRING:
1300 default:
1301 ret = -EINVAL;
1302 goto error;
1303 }
1304
1305set:
1306 new->jit_keyring = reqkey_defl;
1307 commit_creds(new);
1308 return old_setting;
1309error:
1310 abort_creds(new);
1311 return ret;
1312}
1313
1314/*
1315 * Set or clear the timeout on a key.
1316 *
1317 * Either the key must grant the caller Setattr permission or else the caller
1318 * must hold an instantiation authorisation token for the key.
1319 *
1320 * The timeout is either 0 to clear the timeout, or a number of seconds from
1321 * the current time. The key and any links to the key will be automatically
1322 * garbage collected after the timeout expires.
1323 *
1324 * Keys with KEY_FLAG_KEEP set should not be timed out.
1325 *
1326 * If successful, 0 is returned.
1327 */
1328long keyctl_set_timeout(key_serial_t id, unsigned timeout)
1329{
1330 struct key *key, *instkey;
1331 key_ref_t key_ref;
1332 long ret;
1333
1334 key_ref = lookup_user_key(id, KEY_LOOKUP_CREATE | KEY_LOOKUP_PARTIAL,
1335 KEY_NEED_SETATTR);
1336 if (IS_ERR(key_ref)) {
1337 /* setting the timeout on a key under construction is permitted
1338 * if we have the authorisation token handy */
1339 if (PTR_ERR(key_ref) == -EACCES) {
1340 instkey = key_get_instantiation_authkey(id);
1341 if (!IS_ERR(instkey)) {
1342 key_put(instkey);
1343 key_ref = lookup_user_key(id,
1344 KEY_LOOKUP_PARTIAL,
1345 0);
1346 if (!IS_ERR(key_ref))
1347 goto okay;
1348 }
1349 }
1350
1351 ret = PTR_ERR(key_ref);
1352 goto error;
1353 }
1354
1355okay:
1356 key = key_ref_to_ptr(key_ref);
1357 ret = 0;
1358 if (test_bit(KEY_FLAG_KEEP, &key->flags))
1359 ret = -EPERM;
1360 else
1361 key_set_timeout(key, timeout);
1362 key_put(key);
1363
1364error:
1365 return ret;
1366}
1367
1368/*
1369 * Assume (or clear) the authority to instantiate the specified key.
1370 *
1371 * This sets the authoritative token currently in force for key instantiation.
1372 * This must be done for a key to be instantiated. It has the effect of making
1373 * available all the keys from the caller of the request_key() that created a
1374 * key to request_key() calls made by the caller of this function.
1375 *
1376 * The caller must have the instantiation key in their process keyrings with a
1377 * Search permission grant available to the caller.
1378 *
1379 * If the ID given is 0, then the setting will be cleared and 0 returned.
1380 *
1381 * If the ID given has a matching an authorisation key, then that key will be
1382 * set and its ID will be returned. The authorisation key can be read to get
1383 * the callout information passed to request_key().
1384 */
1385long keyctl_assume_authority(key_serial_t id)
1386{
1387 struct key *authkey;
1388 long ret;
1389
1390 /* special key IDs aren't permitted */
1391 ret = -EINVAL;
1392 if (id < 0)
1393 goto error;
1394
1395 /* we divest ourselves of authority if given an ID of 0 */
1396 if (id == 0) {
1397 ret = keyctl_change_reqkey_auth(NULL);
1398 goto error;
1399 }
1400
1401 /* attempt to assume the authority temporarily granted to us whilst we
1402 * instantiate the specified key
1403 * - the authorisation key must be in the current task's keyrings
1404 * somewhere
1405 */
1406 authkey = key_get_instantiation_authkey(id);
1407 if (IS_ERR(authkey)) {
1408 ret = PTR_ERR(authkey);
1409 goto error;
1410 }
1411
1412 ret = keyctl_change_reqkey_auth(authkey);
1413 if (ret == 0)
1414 ret = authkey->serial;
1415 key_put(authkey);
1416error:
1417 return ret;
1418}
1419
1420/*
1421 * Get a key's the LSM security label.
1422 *
1423 * The key must grant the caller View permission for this to work.
1424 *
1425 * If there's a buffer, then up to buflen bytes of data will be placed into it.
1426 *
1427 * If successful, the amount of information available will be returned,
1428 * irrespective of how much was copied (including the terminal NUL).
1429 */
1430long keyctl_get_security(key_serial_t keyid,
1431 char __user *buffer,
1432 size_t buflen)
1433{
1434 struct key *key, *instkey;
1435 key_ref_t key_ref;
1436 char *context;
1437 long ret;
1438
1439 key_ref = lookup_user_key(keyid, KEY_LOOKUP_PARTIAL, KEY_NEED_VIEW);
1440 if (IS_ERR(key_ref)) {
1441 if (PTR_ERR(key_ref) != -EACCES)
1442 return PTR_ERR(key_ref);
1443
1444 /* viewing a key under construction is also permitted if we
1445 * have the authorisation token handy */
1446 instkey = key_get_instantiation_authkey(keyid);
1447 if (IS_ERR(instkey))
1448 return PTR_ERR(instkey);
1449 key_put(instkey);
1450
1451 key_ref = lookup_user_key(keyid, KEY_LOOKUP_PARTIAL, 0);
1452 if (IS_ERR(key_ref))
1453 return PTR_ERR(key_ref);
1454 }
1455
1456 key = key_ref_to_ptr(key_ref);
1457 ret = security_key_getsecurity(key, &context);
1458 if (ret == 0) {
1459 /* if no information was returned, give userspace an empty
1460 * string */
1461 ret = 1;
1462 if (buffer && buflen > 0 &&
1463 copy_to_user(buffer, "", 1) != 0)
1464 ret = -EFAULT;
1465 } else if (ret > 0) {
1466 /* return as much data as there's room for */
1467 if (buffer && buflen > 0) {
1468 if (buflen > ret)
1469 buflen = ret;
1470
1471 if (copy_to_user(buffer, context, buflen) != 0)
1472 ret = -EFAULT;
1473 }
1474
1475 kfree(context);
1476 }
1477
1478 key_ref_put(key_ref);
1479 return ret;
1480}
1481
1482/*
1483 * Attempt to install the calling process's session keyring on the process's
1484 * parent process.
1485 *
1486 * The keyring must exist and must grant the caller LINK permission, and the
1487 * parent process must be single-threaded and must have the same effective
1488 * ownership as this process and mustn't be SUID/SGID.
1489 *
1490 * The keyring will be emplaced on the parent when it next resumes userspace.
1491 *
1492 * If successful, 0 will be returned.
1493 */
1494long keyctl_session_to_parent(void)
1495{
1496 struct task_struct *me, *parent;
1497 const struct cred *mycred, *pcred;
1498 struct callback_head *newwork, *oldwork;
1499 key_ref_t keyring_r;
1500 struct cred *cred;
1501 int ret;
1502
1503 keyring_r = lookup_user_key(KEY_SPEC_SESSION_KEYRING, 0, KEY_NEED_LINK);
1504 if (IS_ERR(keyring_r))
1505 return PTR_ERR(keyring_r);
1506
1507 ret = -ENOMEM;
1508
1509 /* our parent is going to need a new cred struct, a new tgcred struct
1510 * and new security data, so we allocate them here to prevent ENOMEM in
1511 * our parent */
1512 cred = cred_alloc_blank();
1513 if (!cred)
1514 goto error_keyring;
1515 newwork = &cred->rcu;
1516
1517 cred->session_keyring = key_ref_to_ptr(keyring_r);
1518 keyring_r = NULL;
1519 init_task_work(newwork, key_change_session_keyring);
1520
1521 me = current;
1522 rcu_read_lock();
1523 write_lock_irq(&tasklist_lock);
1524
1525 ret = -EPERM;
1526 oldwork = NULL;
1527 parent = me->real_parent;
1528
1529 /* the parent mustn't be init and mustn't be a kernel thread */
1530 if (parent->pid <= 1 || !parent->mm)
1531 goto unlock;
1532
1533 /* the parent must be single threaded */
1534 if (!thread_group_empty(parent))
1535 goto unlock;
1536
1537 /* the parent and the child must have different session keyrings or
1538 * there's no point */
1539 mycred = current_cred();
1540 pcred = __task_cred(parent);
1541 if (mycred == pcred ||
1542 mycred->session_keyring == pcred->session_keyring) {
1543 ret = 0;
1544 goto unlock;
1545 }
1546
1547 /* the parent must have the same effective ownership and mustn't be
1548 * SUID/SGID */
1549 if (!uid_eq(pcred->uid, mycred->euid) ||
1550 !uid_eq(pcred->euid, mycred->euid) ||
1551 !uid_eq(pcred->suid, mycred->euid) ||
1552 !gid_eq(pcred->gid, mycred->egid) ||
1553 !gid_eq(pcred->egid, mycred->egid) ||
1554 !gid_eq(pcred->sgid, mycred->egid))
1555 goto unlock;
1556
1557 /* the keyrings must have the same UID */
1558 if ((pcred->session_keyring &&
1559 !uid_eq(pcred->session_keyring->uid, mycred->euid)) ||
1560 !uid_eq(mycred->session_keyring->uid, mycred->euid))
1561 goto unlock;
1562
1563 /* cancel an already pending keyring replacement */
1564 oldwork = task_work_cancel(parent, key_change_session_keyring);
1565
1566 /* the replacement session keyring is applied just prior to userspace
1567 * restarting */
1568 ret = task_work_add(parent, newwork, true);
1569 if (!ret)
1570 newwork = NULL;
1571unlock:
1572 write_unlock_irq(&tasklist_lock);
1573 rcu_read_unlock();
1574 if (oldwork)
1575 put_cred(container_of(oldwork, struct cred, rcu));
1576 if (newwork)
1577 put_cred(cred);
1578 return ret;
1579
1580error_keyring:
1581 key_ref_put(keyring_r);
1582 return ret;
1583}
1584
1585/*
1586 * Apply a restriction to a given keyring.
1587 *
1588 * The caller must have Setattr permission to change keyring restrictions.
1589 *
1590 * The requested type name may be a NULL pointer to reject all attempts
1591 * to link to the keyring. In this case, _restriction must also be NULL.
1592 * Otherwise, both _type and _restriction must be non-NULL.
1593 *
1594 * Returns 0 if successful.
1595 */
1596long keyctl_restrict_keyring(key_serial_t id, const char __user *_type,
1597 const char __user *_restriction)
1598{
1599 key_ref_t key_ref;
1600 char type[32];
1601 char *restriction = NULL;
1602 long ret;
1603
1604 key_ref = lookup_user_key(id, 0, KEY_NEED_SETATTR);
1605 if (IS_ERR(key_ref))
1606 return PTR_ERR(key_ref);
1607
1608 ret = -EINVAL;
1609 if (_type) {
1610 if (!_restriction)
1611 goto error;
1612
1613 ret = key_get_type_from_user(type, _type, sizeof(type));
1614 if (ret < 0)
1615 goto error;
1616
1617 restriction = strndup_user(_restriction, PAGE_SIZE);
1618 if (IS_ERR(restriction)) {
1619 ret = PTR_ERR(restriction);
1620 goto error;
1621 }
1622 } else {
1623 if (_restriction)
1624 goto error;
1625 }
1626
1627 ret = keyring_restrict(key_ref, _type ? type : NULL, restriction);
1628 kfree(restriction);
1629error:
1630 key_ref_put(key_ref);
1631 return ret;
1632}
1633
1634/*
1635 * The key control system call
1636 */
1637SYSCALL_DEFINE5(keyctl, int, option, unsigned long, arg2, unsigned long, arg3,
1638 unsigned long, arg4, unsigned long, arg5)
1639{
1640 switch (option) {
1641 case KEYCTL_GET_KEYRING_ID:
1642 return keyctl_get_keyring_ID((key_serial_t) arg2,
1643 (int) arg3);
1644
1645 case KEYCTL_JOIN_SESSION_KEYRING:
1646 return keyctl_join_session_keyring((const char __user *) arg2);
1647
1648 case KEYCTL_UPDATE:
1649 return keyctl_update_key((key_serial_t) arg2,
1650 (const void __user *) arg3,
1651 (size_t) arg4);
1652
1653 case KEYCTL_REVOKE:
1654 return keyctl_revoke_key((key_serial_t) arg2);
1655
1656 case KEYCTL_DESCRIBE:
1657 return keyctl_describe_key((key_serial_t) arg2,
1658 (char __user *) arg3,
1659 (unsigned) arg4);
1660
1661 case KEYCTL_CLEAR:
1662 return keyctl_keyring_clear((key_serial_t) arg2);
1663
1664 case KEYCTL_LINK:
1665 return keyctl_keyring_link((key_serial_t) arg2,
1666 (key_serial_t) arg3);
1667
1668 case KEYCTL_UNLINK:
1669 return keyctl_keyring_unlink((key_serial_t) arg2,
1670 (key_serial_t) arg3);
1671
1672 case KEYCTL_SEARCH:
1673 return keyctl_keyring_search((key_serial_t) arg2,
1674 (const char __user *) arg3,
1675 (const char __user *) arg4,
1676 (key_serial_t) arg5);
1677
1678 case KEYCTL_READ:
1679 return keyctl_read_key((key_serial_t) arg2,
1680 (char __user *) arg3,
1681 (size_t) arg4);
1682
1683 case KEYCTL_CHOWN:
1684 return keyctl_chown_key((key_serial_t) arg2,
1685 (uid_t) arg3,
1686 (gid_t) arg4);
1687
1688 case KEYCTL_SETPERM:
1689 return keyctl_setperm_key((key_serial_t) arg2,
1690 (key_perm_t) arg3);
1691
1692 case KEYCTL_INSTANTIATE:
1693 return keyctl_instantiate_key((key_serial_t) arg2,
1694 (const void __user *) arg3,
1695 (size_t) arg4,
1696 (key_serial_t) arg5);
1697
1698 case KEYCTL_NEGATE:
1699 return keyctl_negate_key((key_serial_t) arg2,
1700 (unsigned) arg3,
1701 (key_serial_t) arg4);
1702
1703 case KEYCTL_SET_REQKEY_KEYRING:
1704 return keyctl_set_reqkey_keyring(arg2);
1705
1706 case KEYCTL_SET_TIMEOUT:
1707 return keyctl_set_timeout((key_serial_t) arg2,
1708 (unsigned) arg3);
1709
1710 case KEYCTL_ASSUME_AUTHORITY:
1711 return keyctl_assume_authority((key_serial_t) arg2);
1712
1713 case KEYCTL_GET_SECURITY:
1714 return keyctl_get_security((key_serial_t) arg2,
1715 (char __user *) arg3,
1716 (size_t) arg4);
1717
1718 case KEYCTL_SESSION_TO_PARENT:
1719 return keyctl_session_to_parent();
1720
1721 case KEYCTL_REJECT:
1722 return keyctl_reject_key((key_serial_t) arg2,
1723 (unsigned) arg3,
1724 (unsigned) arg4,
1725 (key_serial_t) arg5);
1726
1727 case KEYCTL_INSTANTIATE_IOV:
1728 return keyctl_instantiate_key_iov(
1729 (key_serial_t) arg2,
1730 (const struct iovec __user *) arg3,
1731 (unsigned) arg4,
1732 (key_serial_t) arg5);
1733
1734 case KEYCTL_INVALIDATE:
1735 return keyctl_invalidate_key((key_serial_t) arg2);
1736
1737 case KEYCTL_GET_PERSISTENT:
1738 return keyctl_get_persistent((uid_t)arg2, (key_serial_t)arg3);
1739
1740 case KEYCTL_DH_COMPUTE:
1741 return keyctl_dh_compute((struct keyctl_dh_params __user *) arg2,
1742 (char __user *) arg3, (size_t) arg4,
1743 (struct keyctl_kdf_params __user *) arg5);
1744
1745 case KEYCTL_RESTRICT_KEYRING:
1746 return keyctl_restrict_keyring((key_serial_t) arg2,
1747 (const char __user *) arg3,
1748 (const char __user *) arg4);
1749
1750 default:
1751 return -EOPNOTSUPP;
1752 }
1753}