Loading...
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/key.h>
18#include <linux/keyctl.h>
19#include <linux/fs.h>
20#include <linux/capability.h>
21#include <linux/string.h>
22#include <linux/err.h>
23#include <linux/vmalloc.h>
24#include <linux/security.h>
25#include <linux/uio.h>
26#include <asm/uaccess.h>
27#include "internal.h"
28
29#define KEY_MAX_DESC_SIZE 4096
30
31static int key_get_type_from_user(char *type,
32 const char __user *_type,
33 unsigned len)
34{
35 int ret;
36
37 ret = strncpy_from_user(type, _type, len);
38 if (ret < 0)
39 return ret;
40 if (ret == 0 || ret >= len)
41 return -EINVAL;
42 if (type[0] == '.')
43 return -EPERM;
44 type[len - 1] = '\0';
45 return 0;
46}
47
48/*
49 * Extract the description of a new key from userspace and either add it as a
50 * new key to the specified keyring or update a matching key in that keyring.
51 *
52 * If the description is NULL or an empty string, the key type is asked to
53 * generate one from the payload.
54 *
55 * The keyring must be writable so that we can attach the key to it.
56 *
57 * If successful, the new key's serial number is returned, otherwise an error
58 * code is returned.
59 */
60SYSCALL_DEFINE5(add_key, const char __user *, _type,
61 const char __user *, _description,
62 const void __user *, _payload,
63 size_t, plen,
64 key_serial_t, ringid)
65{
66 key_ref_t keyring_ref, key_ref;
67 char type[32], *description;
68 void *payload;
69 long ret;
70
71 ret = -EINVAL;
72 if (plen > 1024 * 1024 - 1)
73 goto error;
74
75 /* draw all the data into kernel space */
76 ret = key_get_type_from_user(type, _type, sizeof(type));
77 if (ret < 0)
78 goto error;
79
80 description = NULL;
81 if (_description) {
82 description = strndup_user(_description, KEY_MAX_DESC_SIZE);
83 if (IS_ERR(description)) {
84 ret = PTR_ERR(description);
85 goto error;
86 }
87 if (!*description) {
88 kfree(description);
89 description = NULL;
90 } else if ((description[0] == '.') &&
91 (strncmp(type, "keyring", 7) == 0)) {
92 ret = -EPERM;
93 goto error2;
94 }
95 }
96
97 /* pull the payload in if one was supplied */
98 payload = NULL;
99
100 if (_payload) {
101 ret = -ENOMEM;
102 payload = kmalloc(plen, GFP_KERNEL | __GFP_NOWARN);
103 if (!payload) {
104 if (plen <= PAGE_SIZE)
105 goto error2;
106 payload = vmalloc(plen);
107 if (!payload)
108 goto error2;
109 }
110
111 ret = -EFAULT;
112 if (copy_from_user(payload, _payload, plen) != 0)
113 goto error3;
114 }
115
116 /* find the target keyring (which must be writable) */
117 keyring_ref = lookup_user_key(ringid, KEY_LOOKUP_CREATE, KEY_NEED_WRITE);
118 if (IS_ERR(keyring_ref)) {
119 ret = PTR_ERR(keyring_ref);
120 goto error3;
121 }
122
123 /* create or update the requested key and add it to the target
124 * keyring */
125 key_ref = key_create_or_update(keyring_ref, type, description,
126 payload, plen, KEY_PERM_UNDEF,
127 KEY_ALLOC_IN_QUOTA);
128 if (!IS_ERR(key_ref)) {
129 ret = key_ref_to_ptr(key_ref)->serial;
130 key_ref_put(key_ref);
131 }
132 else {
133 ret = PTR_ERR(key_ref);
134 }
135
136 key_ref_put(keyring_ref);
137 error3:
138 kvfree(payload);
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.
275 *
276 * If successful, the ID of the joined session keyring will be returned.
277 */
278long keyctl_join_session_keyring(const char __user *_name)
279{
280 char *name;
281 long ret;
282
283 /* fetch the name from userspace */
284 name = NULL;
285 if (_name) {
286 name = strndup_user(_name, KEY_MAX_DESC_SIZE);
287 if (IS_ERR(name)) {
288 ret = PTR_ERR(name);
289 goto error;
290 }
291 }
292
293 /* join the session */
294 ret = join_session_keyring(name);
295 kfree(name);
296
297error:
298 return ret;
299}
300
301/*
302 * Update a key's data payload from the given data.
303 *
304 * The key must grant the caller Write permission and the key type must support
305 * updating for this to work. A negative key can be positively instantiated
306 * with this call.
307 *
308 * If successful, 0 will be returned. If the key type does not support
309 * updating, then -EOPNOTSUPP will be returned.
310 */
311long keyctl_update_key(key_serial_t id,
312 const void __user *_payload,
313 size_t plen)
314{
315 key_ref_t key_ref;
316 void *payload;
317 long ret;
318
319 ret = -EINVAL;
320 if (plen > PAGE_SIZE)
321 goto error;
322
323 /* pull the payload in if one was supplied */
324 payload = NULL;
325 if (_payload) {
326 ret = -ENOMEM;
327 payload = kmalloc(plen, GFP_KERNEL);
328 if (!payload)
329 goto error;
330
331 ret = -EFAULT;
332 if (copy_from_user(payload, _payload, plen) != 0)
333 goto error2;
334 }
335
336 /* find the target key (which must be writable) */
337 key_ref = lookup_user_key(id, 0, KEY_NEED_WRITE);
338 if (IS_ERR(key_ref)) {
339 ret = PTR_ERR(key_ref);
340 goto error2;
341 }
342
343 /* update the key */
344 ret = key_update(key_ref, payload, plen);
345
346 key_ref_put(key_ref);
347error2:
348 kfree(payload);
349error:
350 return ret;
351}
352
353/*
354 * Revoke a key.
355 *
356 * The key must be grant the caller Write or Setattr permission for this to
357 * work. The key type should give up its quota claim when revoked. The key
358 * and any links to the key will be automatically garbage collected after a
359 * certain amount of time (/proc/sys/kernel/keys/gc_delay).
360 *
361 * Keys with KEY_FLAG_KEEP set should not be revoked.
362 *
363 * If successful, 0 is returned.
364 */
365long keyctl_revoke_key(key_serial_t id)
366{
367 key_ref_t key_ref;
368 struct key *key;
369 long ret;
370
371 key_ref = lookup_user_key(id, 0, KEY_NEED_WRITE);
372 if (IS_ERR(key_ref)) {
373 ret = PTR_ERR(key_ref);
374 if (ret != -EACCES)
375 goto error;
376 key_ref = lookup_user_key(id, 0, KEY_NEED_SETATTR);
377 if (IS_ERR(key_ref)) {
378 ret = PTR_ERR(key_ref);
379 goto error;
380 }
381 }
382
383 key = key_ref_to_ptr(key_ref);
384 ret = 0;
385 if (test_bit(KEY_FLAG_KEEP, &key->flags))
386 ret = -EPERM;
387 else
388 key_revoke(key);
389
390 key_ref_put(key_ref);
391error:
392 return ret;
393}
394
395/*
396 * Invalidate a key.
397 *
398 * The key must be grant the caller Invalidate permission for this to work.
399 * The key and any links to the key will be automatically garbage collected
400 * immediately.
401 *
402 * Keys with KEY_FLAG_KEEP set should not be invalidated.
403 *
404 * If successful, 0 is returned.
405 */
406long keyctl_invalidate_key(key_serial_t id)
407{
408 key_ref_t key_ref;
409 struct key *key;
410 long ret;
411
412 kenter("%d", id);
413
414 key_ref = lookup_user_key(id, 0, KEY_NEED_SEARCH);
415 if (IS_ERR(key_ref)) {
416 ret = PTR_ERR(key_ref);
417
418 /* Root is permitted to invalidate certain special keys */
419 if (capable(CAP_SYS_ADMIN)) {
420 key_ref = lookup_user_key(id, 0, 0);
421 if (IS_ERR(key_ref))
422 goto error;
423 if (test_bit(KEY_FLAG_ROOT_CAN_INVAL,
424 &key_ref_to_ptr(key_ref)->flags))
425 goto invalidate;
426 goto error_put;
427 }
428
429 goto error;
430 }
431
432invalidate:
433 key = key_ref_to_ptr(key_ref);
434 ret = 0;
435 if (test_bit(KEY_FLAG_KEEP, &key->flags))
436 ret = -EPERM;
437 else
438 key_invalidate(key);
439error_put:
440 key_ref_put(key_ref);
441error:
442 kleave(" = %ld", ret);
443 return ret;
444}
445
446/*
447 * Clear the specified keyring, creating an empty process keyring if one of the
448 * special keyring IDs is used.
449 *
450 * The keyring must grant the caller Write permission and not have
451 * KEY_FLAG_KEEP set for this to work. If successful, 0 will be returned.
452 */
453long keyctl_keyring_clear(key_serial_t ringid)
454{
455 key_ref_t keyring_ref;
456 struct key *keyring;
457 long ret;
458
459 keyring_ref = lookup_user_key(ringid, KEY_LOOKUP_CREATE, KEY_NEED_WRITE);
460 if (IS_ERR(keyring_ref)) {
461 ret = PTR_ERR(keyring_ref);
462
463 /* Root is permitted to invalidate certain special keyrings */
464 if (capable(CAP_SYS_ADMIN)) {
465 keyring_ref = lookup_user_key(ringid, 0, 0);
466 if (IS_ERR(keyring_ref))
467 goto error;
468 if (test_bit(KEY_FLAG_ROOT_CAN_CLEAR,
469 &key_ref_to_ptr(keyring_ref)->flags))
470 goto clear;
471 goto error_put;
472 }
473
474 goto error;
475 }
476
477clear:
478 keyring = key_ref_to_ptr(keyring_ref);
479 if (test_bit(KEY_FLAG_KEEP, &keyring->flags))
480 ret = -EPERM;
481 else
482 ret = keyring_clear(keyring);
483error_put:
484 key_ref_put(keyring_ref);
485error:
486 return ret;
487}
488
489/*
490 * Create a link from a keyring to a key if there's no matching key in the
491 * keyring, otherwise replace the link to the matching key with a link to the
492 * new key.
493 *
494 * The key must grant the caller Link permission and the the keyring must grant
495 * the caller Write permission. Furthermore, if an additional link is created,
496 * the keyring's quota will be extended.
497 *
498 * If successful, 0 will be returned.
499 */
500long keyctl_keyring_link(key_serial_t id, key_serial_t ringid)
501{
502 key_ref_t keyring_ref, key_ref;
503 long ret;
504
505 keyring_ref = lookup_user_key(ringid, KEY_LOOKUP_CREATE, KEY_NEED_WRITE);
506 if (IS_ERR(keyring_ref)) {
507 ret = PTR_ERR(keyring_ref);
508 goto error;
509 }
510
511 key_ref = lookup_user_key(id, KEY_LOOKUP_CREATE, KEY_NEED_LINK);
512 if (IS_ERR(key_ref)) {
513 ret = PTR_ERR(key_ref);
514 goto error2;
515 }
516
517 ret = key_link(key_ref_to_ptr(keyring_ref), key_ref_to_ptr(key_ref));
518
519 key_ref_put(key_ref);
520error2:
521 key_ref_put(keyring_ref);
522error:
523 return ret;
524}
525
526/*
527 * Unlink a key from a keyring.
528 *
529 * The keyring must grant the caller Write permission for this to work; the key
530 * itself need not grant the caller anything. If the last link to a key is
531 * removed then that key will be scheduled for destruction.
532 *
533 * Keys or keyrings with KEY_FLAG_KEEP set should not be unlinked.
534 *
535 * If successful, 0 will be returned.
536 */
537long keyctl_keyring_unlink(key_serial_t id, key_serial_t ringid)
538{
539 key_ref_t keyring_ref, key_ref;
540 struct key *keyring, *key;
541 long ret;
542
543 keyring_ref = lookup_user_key(ringid, 0, KEY_NEED_WRITE);
544 if (IS_ERR(keyring_ref)) {
545 ret = PTR_ERR(keyring_ref);
546 goto error;
547 }
548
549 key_ref = lookup_user_key(id, KEY_LOOKUP_FOR_UNLINK, 0);
550 if (IS_ERR(key_ref)) {
551 ret = PTR_ERR(key_ref);
552 goto error2;
553 }
554
555 keyring = key_ref_to_ptr(keyring_ref);
556 key = key_ref_to_ptr(key_ref);
557 if (test_bit(KEY_FLAG_KEEP, &keyring->flags) &&
558 test_bit(KEY_FLAG_KEEP, &key->flags))
559 ret = -EPERM;
560 else
561 ret = key_unlink(keyring, key);
562
563 key_ref_put(key_ref);
564error2:
565 key_ref_put(keyring_ref);
566error:
567 return ret;
568}
569
570/*
571 * Return a description of a key to userspace.
572 *
573 * The key must grant the caller View permission for this to work.
574 *
575 * If there's a buffer, we place up to buflen bytes of data into it formatted
576 * in the following way:
577 *
578 * type;uid;gid;perm;description<NUL>
579 *
580 * If successful, we return the amount of description available, irrespective
581 * of how much we may have copied into the buffer.
582 */
583long keyctl_describe_key(key_serial_t keyid,
584 char __user *buffer,
585 size_t buflen)
586{
587 struct key *key, *instkey;
588 key_ref_t key_ref;
589 char *infobuf;
590 long ret;
591 int desclen, infolen;
592
593 key_ref = lookup_user_key(keyid, KEY_LOOKUP_PARTIAL, KEY_NEED_VIEW);
594 if (IS_ERR(key_ref)) {
595 /* viewing a key under construction is permitted if we have the
596 * authorisation token handy */
597 if (PTR_ERR(key_ref) == -EACCES) {
598 instkey = key_get_instantiation_authkey(keyid);
599 if (!IS_ERR(instkey)) {
600 key_put(instkey);
601 key_ref = lookup_user_key(keyid,
602 KEY_LOOKUP_PARTIAL,
603 0);
604 if (!IS_ERR(key_ref))
605 goto okay;
606 }
607 }
608
609 ret = PTR_ERR(key_ref);
610 goto error;
611 }
612
613okay:
614 key = key_ref_to_ptr(key_ref);
615 desclen = strlen(key->description);
616
617 /* calculate how much information we're going to return */
618 ret = -ENOMEM;
619 infobuf = kasprintf(GFP_KERNEL,
620 "%s;%d;%d;%08x;",
621 key->type->name,
622 from_kuid_munged(current_user_ns(), key->uid),
623 from_kgid_munged(current_user_ns(), key->gid),
624 key->perm);
625 if (!infobuf)
626 goto error2;
627 infolen = strlen(infobuf);
628 ret = infolen + desclen + 1;
629
630 /* consider returning the data */
631 if (buffer && buflen >= ret) {
632 if (copy_to_user(buffer, infobuf, infolen) != 0 ||
633 copy_to_user(buffer + infolen, key->description,
634 desclen + 1) != 0)
635 ret = -EFAULT;
636 }
637
638 kfree(infobuf);
639error2:
640 key_ref_put(key_ref);
641error:
642 return ret;
643}
644
645/*
646 * Search the specified keyring and any keyrings it links to for a matching
647 * key. Only keyrings that grant the caller Search permission will be searched
648 * (this includes the starting keyring). Only keys with Search permission can
649 * be found.
650 *
651 * If successful, the found key will be linked to the destination keyring if
652 * supplied and the key has Link permission, and the found key ID will be
653 * returned.
654 */
655long keyctl_keyring_search(key_serial_t ringid,
656 const char __user *_type,
657 const char __user *_description,
658 key_serial_t destringid)
659{
660 struct key_type *ktype;
661 key_ref_t keyring_ref, key_ref, dest_ref;
662 char type[32], *description;
663 long ret;
664
665 /* pull the type and description into kernel space */
666 ret = key_get_type_from_user(type, _type, sizeof(type));
667 if (ret < 0)
668 goto error;
669
670 description = strndup_user(_description, KEY_MAX_DESC_SIZE);
671 if (IS_ERR(description)) {
672 ret = PTR_ERR(description);
673 goto error;
674 }
675
676 /* get the keyring at which to begin the search */
677 keyring_ref = lookup_user_key(ringid, 0, KEY_NEED_SEARCH);
678 if (IS_ERR(keyring_ref)) {
679 ret = PTR_ERR(keyring_ref);
680 goto error2;
681 }
682
683 /* get the destination keyring if specified */
684 dest_ref = NULL;
685 if (destringid) {
686 dest_ref = lookup_user_key(destringid, KEY_LOOKUP_CREATE,
687 KEY_NEED_WRITE);
688 if (IS_ERR(dest_ref)) {
689 ret = PTR_ERR(dest_ref);
690 goto error3;
691 }
692 }
693
694 /* find the key type */
695 ktype = key_type_lookup(type);
696 if (IS_ERR(ktype)) {
697 ret = PTR_ERR(ktype);
698 goto error4;
699 }
700
701 /* do the search */
702 key_ref = keyring_search(keyring_ref, ktype, description);
703 if (IS_ERR(key_ref)) {
704 ret = PTR_ERR(key_ref);
705
706 /* treat lack or presence of a negative key the same */
707 if (ret == -EAGAIN)
708 ret = -ENOKEY;
709 goto error5;
710 }
711
712 /* link the resulting key to the destination keyring if we can */
713 if (dest_ref) {
714 ret = key_permission(key_ref, KEY_NEED_LINK);
715 if (ret < 0)
716 goto error6;
717
718 ret = key_link(key_ref_to_ptr(dest_ref), key_ref_to_ptr(key_ref));
719 if (ret < 0)
720 goto error6;
721 }
722
723 ret = key_ref_to_ptr(key_ref)->serial;
724
725error6:
726 key_ref_put(key_ref);
727error5:
728 key_type_put(ktype);
729error4:
730 key_ref_put(dest_ref);
731error3:
732 key_ref_put(keyring_ref);
733error2:
734 kfree(description);
735error:
736 return ret;
737}
738
739/*
740 * Read a key's payload.
741 *
742 * The key must either grant the caller Read permission, or it must grant the
743 * caller Search permission when searched for from the process keyrings.
744 *
745 * If successful, we place up to buflen bytes of data into the buffer, if one
746 * is provided, and return the amount of data that is available in the key,
747 * irrespective of how much we copied into the buffer.
748 */
749long keyctl_read_key(key_serial_t keyid, char __user *buffer, size_t buflen)
750{
751 struct key *key;
752 key_ref_t key_ref;
753 long ret;
754
755 /* find the key first */
756 key_ref = lookup_user_key(keyid, 0, 0);
757 if (IS_ERR(key_ref)) {
758 ret = -ENOKEY;
759 goto error;
760 }
761
762 key = key_ref_to_ptr(key_ref);
763
764 /* see if we can read it directly */
765 ret = key_permission(key_ref, KEY_NEED_READ);
766 if (ret == 0)
767 goto can_read_key;
768 if (ret != -EACCES)
769 goto error;
770
771 /* we can't; see if it's searchable from this process's keyrings
772 * - we automatically take account of the fact that it may be
773 * dangling off an instantiation key
774 */
775 if (!is_key_possessed(key_ref)) {
776 ret = -EACCES;
777 goto error2;
778 }
779
780 /* the key is probably readable - now try to read it */
781can_read_key:
782 ret = -EOPNOTSUPP;
783 if (key->type->read) {
784 /* Read the data with the semaphore held (since we might sleep)
785 * to protect against the key being updated or revoked.
786 */
787 down_read(&key->sem);
788 ret = key_validate(key);
789 if (ret == 0)
790 ret = key->type->read(key, buffer, buflen);
791 up_read(&key->sem);
792 }
793
794error2:
795 key_put(key);
796error:
797 return ret;
798}
799
800/*
801 * Change the ownership of a key
802 *
803 * The key must grant the caller Setattr permission for this to work, though
804 * the key need not be fully instantiated yet. For the UID to be changed, or
805 * for the GID to be changed to a group the caller is not a member of, the
806 * caller must have sysadmin capability. If either uid or gid is -1 then that
807 * attribute is not changed.
808 *
809 * If the UID is to be changed, the new user must have sufficient quota to
810 * accept the key. The quota deduction will be removed from the old user to
811 * the new user should the attribute be changed.
812 *
813 * If successful, 0 will be returned.
814 */
815long keyctl_chown_key(key_serial_t id, uid_t user, gid_t group)
816{
817 struct key_user *newowner, *zapowner = NULL;
818 struct key *key;
819 key_ref_t key_ref;
820 long ret;
821 kuid_t uid;
822 kgid_t gid;
823
824 uid = make_kuid(current_user_ns(), user);
825 gid = make_kgid(current_user_ns(), group);
826 ret = -EINVAL;
827 if ((user != (uid_t) -1) && !uid_valid(uid))
828 goto error;
829 if ((group != (gid_t) -1) && !gid_valid(gid))
830 goto error;
831
832 ret = 0;
833 if (user == (uid_t) -1 && group == (gid_t) -1)
834 goto error;
835
836 key_ref = lookup_user_key(id, KEY_LOOKUP_CREATE | KEY_LOOKUP_PARTIAL,
837 KEY_NEED_SETATTR);
838 if (IS_ERR(key_ref)) {
839 ret = PTR_ERR(key_ref);
840 goto error;
841 }
842
843 key = key_ref_to_ptr(key_ref);
844
845 /* make the changes with the locks held to prevent chown/chown races */
846 ret = -EACCES;
847 down_write(&key->sem);
848
849 if (!capable(CAP_SYS_ADMIN)) {
850 /* only the sysadmin can chown a key to some other UID */
851 if (user != (uid_t) -1 && !uid_eq(key->uid, uid))
852 goto error_put;
853
854 /* only the sysadmin can set the key's GID to a group other
855 * than one of those that the current process subscribes to */
856 if (group != (gid_t) -1 && !gid_eq(gid, key->gid) && !in_group_p(gid))
857 goto error_put;
858 }
859
860 /* change the UID */
861 if (user != (uid_t) -1 && !uid_eq(uid, key->uid)) {
862 ret = -ENOMEM;
863 newowner = key_user_lookup(uid);
864 if (!newowner)
865 goto error_put;
866
867 /* transfer the quota burden to the new user */
868 if (test_bit(KEY_FLAG_IN_QUOTA, &key->flags)) {
869 unsigned maxkeys = uid_eq(uid, GLOBAL_ROOT_UID) ?
870 key_quota_root_maxkeys : key_quota_maxkeys;
871 unsigned maxbytes = uid_eq(uid, GLOBAL_ROOT_UID) ?
872 key_quota_root_maxbytes : key_quota_maxbytes;
873
874 spin_lock(&newowner->lock);
875 if (newowner->qnkeys + 1 >= maxkeys ||
876 newowner->qnbytes + key->quotalen >= maxbytes ||
877 newowner->qnbytes + key->quotalen <
878 newowner->qnbytes)
879 goto quota_overrun;
880
881 newowner->qnkeys++;
882 newowner->qnbytes += key->quotalen;
883 spin_unlock(&newowner->lock);
884
885 spin_lock(&key->user->lock);
886 key->user->qnkeys--;
887 key->user->qnbytes -= key->quotalen;
888 spin_unlock(&key->user->lock);
889 }
890
891 atomic_dec(&key->user->nkeys);
892 atomic_inc(&newowner->nkeys);
893
894 if (test_bit(KEY_FLAG_INSTANTIATED, &key->flags)) {
895 atomic_dec(&key->user->nikeys);
896 atomic_inc(&newowner->nikeys);
897 }
898
899 zapowner = key->user;
900 key->user = newowner;
901 key->uid = uid;
902 }
903
904 /* change the GID */
905 if (group != (gid_t) -1)
906 key->gid = gid;
907
908 ret = 0;
909
910error_put:
911 up_write(&key->sem);
912 key_put(key);
913 if (zapowner)
914 key_user_put(zapowner);
915error:
916 return ret;
917
918quota_overrun:
919 spin_unlock(&newowner->lock);
920 zapowner = newowner;
921 ret = -EDQUOT;
922 goto error_put;
923}
924
925/*
926 * Change the permission mask on a key.
927 *
928 * The key must grant the caller Setattr permission for this to work, though
929 * the key need not be fully instantiated yet. If the caller does not have
930 * sysadmin capability, it may only change the permission on keys that it owns.
931 */
932long keyctl_setperm_key(key_serial_t id, key_perm_t perm)
933{
934 struct key *key;
935 key_ref_t key_ref;
936 long ret;
937
938 ret = -EINVAL;
939 if (perm & ~(KEY_POS_ALL | KEY_USR_ALL | KEY_GRP_ALL | KEY_OTH_ALL))
940 goto error;
941
942 key_ref = lookup_user_key(id, KEY_LOOKUP_CREATE | KEY_LOOKUP_PARTIAL,
943 KEY_NEED_SETATTR);
944 if (IS_ERR(key_ref)) {
945 ret = PTR_ERR(key_ref);
946 goto error;
947 }
948
949 key = key_ref_to_ptr(key_ref);
950
951 /* make the changes with the locks held to prevent chown/chmod races */
952 ret = -EACCES;
953 down_write(&key->sem);
954
955 /* if we're not the sysadmin, we can only change a key that we own */
956 if (capable(CAP_SYS_ADMIN) || uid_eq(key->uid, current_fsuid())) {
957 key->perm = perm;
958 ret = 0;
959 }
960
961 up_write(&key->sem);
962 key_put(key);
963error:
964 return ret;
965}
966
967/*
968 * Get the destination keyring for instantiation and check that the caller has
969 * Write permission on it.
970 */
971static long get_instantiation_keyring(key_serial_t ringid,
972 struct request_key_auth *rka,
973 struct key **_dest_keyring)
974{
975 key_ref_t dkref;
976
977 *_dest_keyring = NULL;
978
979 /* just return a NULL pointer if we weren't asked to make a link */
980 if (ringid == 0)
981 return 0;
982
983 /* if a specific keyring is nominated by ID, then use that */
984 if (ringid > 0) {
985 dkref = lookup_user_key(ringid, KEY_LOOKUP_CREATE, KEY_NEED_WRITE);
986 if (IS_ERR(dkref))
987 return PTR_ERR(dkref);
988 *_dest_keyring = key_ref_to_ptr(dkref);
989 return 0;
990 }
991
992 if (ringid == KEY_SPEC_REQKEY_AUTH_KEY)
993 return -EINVAL;
994
995 /* otherwise specify the destination keyring recorded in the
996 * authorisation key (any KEY_SPEC_*_KEYRING) */
997 if (ringid >= KEY_SPEC_REQUESTOR_KEYRING) {
998 *_dest_keyring = key_get(rka->dest_keyring);
999 return 0;
1000 }
1001
1002 return -ENOKEY;
1003}
1004
1005/*
1006 * Change the request_key authorisation key on the current process.
1007 */
1008static int keyctl_change_reqkey_auth(struct key *key)
1009{
1010 struct cred *new;
1011
1012 new = prepare_creds();
1013 if (!new)
1014 return -ENOMEM;
1015
1016 key_put(new->request_key_auth);
1017 new->request_key_auth = key_get(key);
1018
1019 return commit_creds(new);
1020}
1021
1022/*
1023 * Instantiate a key with the specified payload and link the key into the
1024 * destination keyring if one is given.
1025 *
1026 * The caller must have the appropriate instantiation permit set for this to
1027 * work (see keyctl_assume_authority). No other permissions are required.
1028 *
1029 * If successful, 0 will be returned.
1030 */
1031long keyctl_instantiate_key_common(key_serial_t id,
1032 struct iov_iter *from,
1033 key_serial_t ringid)
1034{
1035 const struct cred *cred = current_cred();
1036 struct request_key_auth *rka;
1037 struct key *instkey, *dest_keyring;
1038 size_t plen = from ? iov_iter_count(from) : 0;
1039 void *payload;
1040 long ret;
1041
1042 kenter("%d,,%zu,%d", id, plen, ringid);
1043
1044 if (!plen)
1045 from = NULL;
1046
1047 ret = -EINVAL;
1048 if (plen > 1024 * 1024 - 1)
1049 goto error;
1050
1051 /* the appropriate instantiation authorisation key must have been
1052 * assumed before calling this */
1053 ret = -EPERM;
1054 instkey = cred->request_key_auth;
1055 if (!instkey)
1056 goto error;
1057
1058 rka = instkey->payload.data[0];
1059 if (rka->target_key->serial != id)
1060 goto error;
1061
1062 /* pull the payload in if one was supplied */
1063 payload = NULL;
1064
1065 if (from) {
1066 ret = -ENOMEM;
1067 payload = kmalloc(plen, GFP_KERNEL);
1068 if (!payload) {
1069 if (plen <= PAGE_SIZE)
1070 goto error;
1071 payload = vmalloc(plen);
1072 if (!payload)
1073 goto error;
1074 }
1075
1076 ret = -EFAULT;
1077 if (copy_from_iter(payload, plen, from) != plen)
1078 goto error2;
1079 }
1080
1081 /* find the destination keyring amongst those belonging to the
1082 * requesting task */
1083 ret = get_instantiation_keyring(ringid, rka, &dest_keyring);
1084 if (ret < 0)
1085 goto error2;
1086
1087 /* instantiate the key and link it into a keyring */
1088 ret = key_instantiate_and_link(rka->target_key, payload, plen,
1089 dest_keyring, instkey);
1090
1091 key_put(dest_keyring);
1092
1093 /* discard the assumed authority if it's just been disabled by
1094 * instantiation of the key */
1095 if (ret == 0)
1096 keyctl_change_reqkey_auth(NULL);
1097
1098error2:
1099 kvfree(payload);
1100error:
1101 return ret;
1102}
1103
1104/*
1105 * Instantiate a key with the specified payload and link the key into the
1106 * destination keyring if one is given.
1107 *
1108 * The caller must have the appropriate instantiation permit set for this to
1109 * work (see keyctl_assume_authority). No other permissions are required.
1110 *
1111 * If successful, 0 will be returned.
1112 */
1113long keyctl_instantiate_key(key_serial_t id,
1114 const void __user *_payload,
1115 size_t plen,
1116 key_serial_t ringid)
1117{
1118 if (_payload && plen) {
1119 struct iovec iov;
1120 struct iov_iter from;
1121 int ret;
1122
1123 ret = import_single_range(WRITE, (void __user *)_payload, plen,
1124 &iov, &from);
1125 if (unlikely(ret))
1126 return ret;
1127
1128 return keyctl_instantiate_key_common(id, &from, ringid);
1129 }
1130
1131 return keyctl_instantiate_key_common(id, NULL, ringid);
1132}
1133
1134/*
1135 * Instantiate a key with the specified multipart payload and link the key into
1136 * the destination keyring if one is given.
1137 *
1138 * The caller must have the appropriate instantiation permit set for this to
1139 * work (see keyctl_assume_authority). No other permissions are required.
1140 *
1141 * If successful, 0 will be returned.
1142 */
1143long keyctl_instantiate_key_iov(key_serial_t id,
1144 const struct iovec __user *_payload_iov,
1145 unsigned ioc,
1146 key_serial_t ringid)
1147{
1148 struct iovec iovstack[UIO_FASTIOV], *iov = iovstack;
1149 struct iov_iter from;
1150 long ret;
1151
1152 if (!_payload_iov)
1153 ioc = 0;
1154
1155 ret = import_iovec(WRITE, _payload_iov, ioc,
1156 ARRAY_SIZE(iovstack), &iov, &from);
1157 if (ret < 0)
1158 return ret;
1159 ret = keyctl_instantiate_key_common(id, &from, ringid);
1160 kfree(iov);
1161 return ret;
1162}
1163
1164/*
1165 * Negatively instantiate the key with the given timeout (in seconds) and link
1166 * the key into the destination keyring if one is given.
1167 *
1168 * The caller must have the appropriate instantiation permit set for this to
1169 * work (see keyctl_assume_authority). No other permissions are required.
1170 *
1171 * The key and any links to the key will be automatically garbage collected
1172 * after the timeout expires.
1173 *
1174 * Negative keys are used to rate limit repeated request_key() calls by causing
1175 * them to return -ENOKEY until the negative key expires.
1176 *
1177 * If successful, 0 will be returned.
1178 */
1179long keyctl_negate_key(key_serial_t id, unsigned timeout, key_serial_t ringid)
1180{
1181 return keyctl_reject_key(id, timeout, ENOKEY, ringid);
1182}
1183
1184/*
1185 * Negatively instantiate the key with the given timeout (in seconds) and error
1186 * code and link the key into the destination keyring if one is given.
1187 *
1188 * The caller must have the appropriate instantiation permit set for this to
1189 * work (see keyctl_assume_authority). No other permissions are required.
1190 *
1191 * The key and any links to the key will be automatically garbage collected
1192 * after the timeout expires.
1193 *
1194 * Negative keys are used to rate limit repeated request_key() calls by causing
1195 * them to return the specified error code until the negative key expires.
1196 *
1197 * If successful, 0 will be returned.
1198 */
1199long keyctl_reject_key(key_serial_t id, unsigned timeout, unsigned error,
1200 key_serial_t ringid)
1201{
1202 const struct cred *cred = current_cred();
1203 struct request_key_auth *rka;
1204 struct key *instkey, *dest_keyring;
1205 long ret;
1206
1207 kenter("%d,%u,%u,%d", id, timeout, error, ringid);
1208
1209 /* must be a valid error code and mustn't be a kernel special */
1210 if (error <= 0 ||
1211 error >= MAX_ERRNO ||
1212 error == ERESTARTSYS ||
1213 error == ERESTARTNOINTR ||
1214 error == ERESTARTNOHAND ||
1215 error == ERESTART_RESTARTBLOCK)
1216 return -EINVAL;
1217
1218 /* the appropriate instantiation authorisation key must have been
1219 * assumed before calling this */
1220 ret = -EPERM;
1221 instkey = cred->request_key_auth;
1222 if (!instkey)
1223 goto error;
1224
1225 rka = instkey->payload.data[0];
1226 if (rka->target_key->serial != id)
1227 goto error;
1228
1229 /* find the destination keyring if present (which must also be
1230 * writable) */
1231 ret = get_instantiation_keyring(ringid, rka, &dest_keyring);
1232 if (ret < 0)
1233 goto error;
1234
1235 /* instantiate the key and link it into a keyring */
1236 ret = key_reject_and_link(rka->target_key, timeout, error,
1237 dest_keyring, instkey);
1238
1239 key_put(dest_keyring);
1240
1241 /* discard the assumed authority if it's just been disabled by
1242 * instantiation of the key */
1243 if (ret == 0)
1244 keyctl_change_reqkey_auth(NULL);
1245
1246error:
1247 return ret;
1248}
1249
1250/*
1251 * Read or set the default keyring in which request_key() will cache keys and
1252 * return the old setting.
1253 *
1254 * If a process keyring is specified then this will be created if it doesn't
1255 * yet exist. The old setting will be returned if successful.
1256 */
1257long keyctl_set_reqkey_keyring(int reqkey_defl)
1258{
1259 struct cred *new;
1260 int ret, old_setting;
1261
1262 old_setting = current_cred_xxx(jit_keyring);
1263
1264 if (reqkey_defl == KEY_REQKEY_DEFL_NO_CHANGE)
1265 return old_setting;
1266
1267 new = prepare_creds();
1268 if (!new)
1269 return -ENOMEM;
1270
1271 switch (reqkey_defl) {
1272 case KEY_REQKEY_DEFL_THREAD_KEYRING:
1273 ret = install_thread_keyring_to_cred(new);
1274 if (ret < 0)
1275 goto error;
1276 goto set;
1277
1278 case KEY_REQKEY_DEFL_PROCESS_KEYRING:
1279 ret = install_process_keyring_to_cred(new);
1280 if (ret < 0) {
1281 if (ret != -EEXIST)
1282 goto error;
1283 ret = 0;
1284 }
1285 goto set;
1286
1287 case KEY_REQKEY_DEFL_DEFAULT:
1288 case KEY_REQKEY_DEFL_SESSION_KEYRING:
1289 case KEY_REQKEY_DEFL_USER_KEYRING:
1290 case KEY_REQKEY_DEFL_USER_SESSION_KEYRING:
1291 case KEY_REQKEY_DEFL_REQUESTOR_KEYRING:
1292 goto set;
1293
1294 case KEY_REQKEY_DEFL_NO_CHANGE:
1295 case KEY_REQKEY_DEFL_GROUP_KEYRING:
1296 default:
1297 ret = -EINVAL;
1298 goto error;
1299 }
1300
1301set:
1302 new->jit_keyring = reqkey_defl;
1303 commit_creds(new);
1304 return old_setting;
1305error:
1306 abort_creds(new);
1307 return ret;
1308}
1309
1310/*
1311 * Set or clear the timeout on a key.
1312 *
1313 * Either the key must grant the caller Setattr permission or else the caller
1314 * must hold an instantiation authorisation token for the key.
1315 *
1316 * The timeout is either 0 to clear the timeout, or a number of seconds from
1317 * the current time. The key and any links to the key will be automatically
1318 * garbage collected after the timeout expires.
1319 *
1320 * Keys with KEY_FLAG_KEEP set should not be timed out.
1321 *
1322 * If successful, 0 is returned.
1323 */
1324long keyctl_set_timeout(key_serial_t id, unsigned timeout)
1325{
1326 struct key *key, *instkey;
1327 key_ref_t key_ref;
1328 long ret;
1329
1330 key_ref = lookup_user_key(id, KEY_LOOKUP_CREATE | KEY_LOOKUP_PARTIAL,
1331 KEY_NEED_SETATTR);
1332 if (IS_ERR(key_ref)) {
1333 /* setting the timeout on a key under construction is permitted
1334 * if we have the authorisation token handy */
1335 if (PTR_ERR(key_ref) == -EACCES) {
1336 instkey = key_get_instantiation_authkey(id);
1337 if (!IS_ERR(instkey)) {
1338 key_put(instkey);
1339 key_ref = lookup_user_key(id,
1340 KEY_LOOKUP_PARTIAL,
1341 0);
1342 if (!IS_ERR(key_ref))
1343 goto okay;
1344 }
1345 }
1346
1347 ret = PTR_ERR(key_ref);
1348 goto error;
1349 }
1350
1351okay:
1352 key = key_ref_to_ptr(key_ref);
1353 ret = 0;
1354 if (test_bit(KEY_FLAG_KEEP, &key->flags))
1355 ret = -EPERM;
1356 else
1357 key_set_timeout(key, timeout);
1358 key_put(key);
1359
1360error:
1361 return ret;
1362}
1363
1364/*
1365 * Assume (or clear) the authority to instantiate the specified key.
1366 *
1367 * This sets the authoritative token currently in force for key instantiation.
1368 * This must be done for a key to be instantiated. It has the effect of making
1369 * available all the keys from the caller of the request_key() that created a
1370 * key to request_key() calls made by the caller of this function.
1371 *
1372 * The caller must have the instantiation key in their process keyrings with a
1373 * Search permission grant available to the caller.
1374 *
1375 * If the ID given is 0, then the setting will be cleared and 0 returned.
1376 *
1377 * If the ID given has a matching an authorisation key, then that key will be
1378 * set and its ID will be returned. The authorisation key can be read to get
1379 * the callout information passed to request_key().
1380 */
1381long keyctl_assume_authority(key_serial_t id)
1382{
1383 struct key *authkey;
1384 long ret;
1385
1386 /* special key IDs aren't permitted */
1387 ret = -EINVAL;
1388 if (id < 0)
1389 goto error;
1390
1391 /* we divest ourselves of authority if given an ID of 0 */
1392 if (id == 0) {
1393 ret = keyctl_change_reqkey_auth(NULL);
1394 goto error;
1395 }
1396
1397 /* attempt to assume the authority temporarily granted to us whilst we
1398 * instantiate the specified key
1399 * - the authorisation key must be in the current task's keyrings
1400 * somewhere
1401 */
1402 authkey = key_get_instantiation_authkey(id);
1403 if (IS_ERR(authkey)) {
1404 ret = PTR_ERR(authkey);
1405 goto error;
1406 }
1407
1408 ret = keyctl_change_reqkey_auth(authkey);
1409 if (ret < 0)
1410 goto error;
1411 key_put(authkey);
1412
1413 ret = authkey->serial;
1414error:
1415 return ret;
1416}
1417
1418/*
1419 * Get a key's the LSM security label.
1420 *
1421 * The key must grant the caller View permission for this to work.
1422 *
1423 * If there's a buffer, then up to buflen bytes of data will be placed into it.
1424 *
1425 * If successful, the amount of information available will be returned,
1426 * irrespective of how much was copied (including the terminal NUL).
1427 */
1428long keyctl_get_security(key_serial_t keyid,
1429 char __user *buffer,
1430 size_t buflen)
1431{
1432 struct key *key, *instkey;
1433 key_ref_t key_ref;
1434 char *context;
1435 long ret;
1436
1437 key_ref = lookup_user_key(keyid, KEY_LOOKUP_PARTIAL, KEY_NEED_VIEW);
1438 if (IS_ERR(key_ref)) {
1439 if (PTR_ERR(key_ref) != -EACCES)
1440 return PTR_ERR(key_ref);
1441
1442 /* viewing a key under construction is also permitted if we
1443 * have the authorisation token handy */
1444 instkey = key_get_instantiation_authkey(keyid);
1445 if (IS_ERR(instkey))
1446 return PTR_ERR(instkey);
1447 key_put(instkey);
1448
1449 key_ref = lookup_user_key(keyid, KEY_LOOKUP_PARTIAL, 0);
1450 if (IS_ERR(key_ref))
1451 return PTR_ERR(key_ref);
1452 }
1453
1454 key = key_ref_to_ptr(key_ref);
1455 ret = security_key_getsecurity(key, &context);
1456 if (ret == 0) {
1457 /* if no information was returned, give userspace an empty
1458 * string */
1459 ret = 1;
1460 if (buffer && buflen > 0 &&
1461 copy_to_user(buffer, "", 1) != 0)
1462 ret = -EFAULT;
1463 } else if (ret > 0) {
1464 /* return as much data as there's room for */
1465 if (buffer && buflen > 0) {
1466 if (buflen > ret)
1467 buflen = ret;
1468
1469 if (copy_to_user(buffer, context, buflen) != 0)
1470 ret = -EFAULT;
1471 }
1472
1473 kfree(context);
1474 }
1475
1476 key_ref_put(key_ref);
1477 return ret;
1478}
1479
1480/*
1481 * Attempt to install the calling process's session keyring on the process's
1482 * parent process.
1483 *
1484 * The keyring must exist and must grant the caller LINK permission, and the
1485 * parent process must be single-threaded and must have the same effective
1486 * ownership as this process and mustn't be SUID/SGID.
1487 *
1488 * The keyring will be emplaced on the parent when it next resumes userspace.
1489 *
1490 * If successful, 0 will be returned.
1491 */
1492long keyctl_session_to_parent(void)
1493{
1494 struct task_struct *me, *parent;
1495 const struct cred *mycred, *pcred;
1496 struct callback_head *newwork, *oldwork;
1497 key_ref_t keyring_r;
1498 struct cred *cred;
1499 int ret;
1500
1501 keyring_r = lookup_user_key(KEY_SPEC_SESSION_KEYRING, 0, KEY_NEED_LINK);
1502 if (IS_ERR(keyring_r))
1503 return PTR_ERR(keyring_r);
1504
1505 ret = -ENOMEM;
1506
1507 /* our parent is going to need a new cred struct, a new tgcred struct
1508 * and new security data, so we allocate them here to prevent ENOMEM in
1509 * our parent */
1510 cred = cred_alloc_blank();
1511 if (!cred)
1512 goto error_keyring;
1513 newwork = &cred->rcu;
1514
1515 cred->session_keyring = key_ref_to_ptr(keyring_r);
1516 keyring_r = NULL;
1517 init_task_work(newwork, key_change_session_keyring);
1518
1519 me = current;
1520 rcu_read_lock();
1521 write_lock_irq(&tasklist_lock);
1522
1523 ret = -EPERM;
1524 oldwork = NULL;
1525 parent = me->real_parent;
1526
1527 /* the parent mustn't be init and mustn't be a kernel thread */
1528 if (parent->pid <= 1 || !parent->mm)
1529 goto unlock;
1530
1531 /* the parent must be single threaded */
1532 if (!thread_group_empty(parent))
1533 goto unlock;
1534
1535 /* the parent and the child must have different session keyrings or
1536 * there's no point */
1537 mycred = current_cred();
1538 pcred = __task_cred(parent);
1539 if (mycred == pcred ||
1540 mycred->session_keyring == pcred->session_keyring) {
1541 ret = 0;
1542 goto unlock;
1543 }
1544
1545 /* the parent must have the same effective ownership and mustn't be
1546 * SUID/SGID */
1547 if (!uid_eq(pcred->uid, mycred->euid) ||
1548 !uid_eq(pcred->euid, mycred->euid) ||
1549 !uid_eq(pcred->suid, mycred->euid) ||
1550 !gid_eq(pcred->gid, mycred->egid) ||
1551 !gid_eq(pcred->egid, mycred->egid) ||
1552 !gid_eq(pcred->sgid, mycred->egid))
1553 goto unlock;
1554
1555 /* the keyrings must have the same UID */
1556 if ((pcred->session_keyring &&
1557 !uid_eq(pcred->session_keyring->uid, mycred->euid)) ||
1558 !uid_eq(mycred->session_keyring->uid, mycred->euid))
1559 goto unlock;
1560
1561 /* cancel an already pending keyring replacement */
1562 oldwork = task_work_cancel(parent, key_change_session_keyring);
1563
1564 /* the replacement session keyring is applied just prior to userspace
1565 * restarting */
1566 ret = task_work_add(parent, newwork, true);
1567 if (!ret)
1568 newwork = NULL;
1569unlock:
1570 write_unlock_irq(&tasklist_lock);
1571 rcu_read_unlock();
1572 if (oldwork)
1573 put_cred(container_of(oldwork, struct cred, rcu));
1574 if (newwork)
1575 put_cred(cred);
1576 return ret;
1577
1578error_keyring:
1579 key_ref_put(keyring_r);
1580 return ret;
1581}
1582
1583/*
1584 * The key control system call
1585 */
1586SYSCALL_DEFINE5(keyctl, int, option, unsigned long, arg2, unsigned long, arg3,
1587 unsigned long, arg4, unsigned long, arg5)
1588{
1589 switch (option) {
1590 case KEYCTL_GET_KEYRING_ID:
1591 return keyctl_get_keyring_ID((key_serial_t) arg2,
1592 (int) arg3);
1593
1594 case KEYCTL_JOIN_SESSION_KEYRING:
1595 return keyctl_join_session_keyring((const char __user *) arg2);
1596
1597 case KEYCTL_UPDATE:
1598 return keyctl_update_key((key_serial_t) arg2,
1599 (const void __user *) arg3,
1600 (size_t) arg4);
1601
1602 case KEYCTL_REVOKE:
1603 return keyctl_revoke_key((key_serial_t) arg2);
1604
1605 case KEYCTL_DESCRIBE:
1606 return keyctl_describe_key((key_serial_t) arg2,
1607 (char __user *) arg3,
1608 (unsigned) arg4);
1609
1610 case KEYCTL_CLEAR:
1611 return keyctl_keyring_clear((key_serial_t) arg2);
1612
1613 case KEYCTL_LINK:
1614 return keyctl_keyring_link((key_serial_t) arg2,
1615 (key_serial_t) arg3);
1616
1617 case KEYCTL_UNLINK:
1618 return keyctl_keyring_unlink((key_serial_t) arg2,
1619 (key_serial_t) arg3);
1620
1621 case KEYCTL_SEARCH:
1622 return keyctl_keyring_search((key_serial_t) arg2,
1623 (const char __user *) arg3,
1624 (const char __user *) arg4,
1625 (key_serial_t) arg5);
1626
1627 case KEYCTL_READ:
1628 return keyctl_read_key((key_serial_t) arg2,
1629 (char __user *) arg3,
1630 (size_t) arg4);
1631
1632 case KEYCTL_CHOWN:
1633 return keyctl_chown_key((key_serial_t) arg2,
1634 (uid_t) arg3,
1635 (gid_t) arg4);
1636
1637 case KEYCTL_SETPERM:
1638 return keyctl_setperm_key((key_serial_t) arg2,
1639 (key_perm_t) arg3);
1640
1641 case KEYCTL_INSTANTIATE:
1642 return keyctl_instantiate_key((key_serial_t) arg2,
1643 (const void __user *) arg3,
1644 (size_t) arg4,
1645 (key_serial_t) arg5);
1646
1647 case KEYCTL_NEGATE:
1648 return keyctl_negate_key((key_serial_t) arg2,
1649 (unsigned) arg3,
1650 (key_serial_t) arg4);
1651
1652 case KEYCTL_SET_REQKEY_KEYRING:
1653 return keyctl_set_reqkey_keyring(arg2);
1654
1655 case KEYCTL_SET_TIMEOUT:
1656 return keyctl_set_timeout((key_serial_t) arg2,
1657 (unsigned) arg3);
1658
1659 case KEYCTL_ASSUME_AUTHORITY:
1660 return keyctl_assume_authority((key_serial_t) arg2);
1661
1662 case KEYCTL_GET_SECURITY:
1663 return keyctl_get_security((key_serial_t) arg2,
1664 (char __user *) arg3,
1665 (size_t) arg4);
1666
1667 case KEYCTL_SESSION_TO_PARENT:
1668 return keyctl_session_to_parent();
1669
1670 case KEYCTL_REJECT:
1671 return keyctl_reject_key((key_serial_t) arg2,
1672 (unsigned) arg3,
1673 (unsigned) arg4,
1674 (key_serial_t) arg5);
1675
1676 case KEYCTL_INSTANTIATE_IOV:
1677 return keyctl_instantiate_key_iov(
1678 (key_serial_t) arg2,
1679 (const struct iovec __user *) arg3,
1680 (unsigned) arg4,
1681 (key_serial_t) arg5);
1682
1683 case KEYCTL_INVALIDATE:
1684 return keyctl_invalidate_key((key_serial_t) arg2);
1685
1686 case KEYCTL_GET_PERSISTENT:
1687 return keyctl_get_persistent((uid_t)arg2, (key_serial_t)arg3);
1688
1689 default:
1690 return -EOPNOTSUPP;
1691 }
1692}
1// SPDX-License-Identifier: GPL-2.0-or-later
2/* Userspace key control operations
3 *
4 * Copyright (C) 2004-5 Red Hat, Inc. All Rights Reserved.
5 * Written by David Howells (dhowells@redhat.com)
6 */
7
8#include <linux/init.h>
9#include <linux/sched.h>
10#include <linux/sched/task.h>
11#include <linux/slab.h>
12#include <linux/syscalls.h>
13#include <linux/key.h>
14#include <linux/keyctl.h>
15#include <linux/fs.h>
16#include <linux/capability.h>
17#include <linux/cred.h>
18#include <linux/string.h>
19#include <linux/err.h>
20#include <linux/vmalloc.h>
21#include <linux/security.h>
22#include <linux/uio.h>
23#include <linux/uaccess.h>
24#include <keys/request_key_auth-type.h>
25#include "internal.h"
26
27#define KEY_MAX_DESC_SIZE 4096
28
29static const unsigned char keyrings_capabilities[2] = {
30 [0] = (KEYCTL_CAPS0_CAPABILITIES |
31 (IS_ENABLED(CONFIG_PERSISTENT_KEYRINGS) ? KEYCTL_CAPS0_PERSISTENT_KEYRINGS : 0) |
32 (IS_ENABLED(CONFIG_KEY_DH_OPERATIONS) ? KEYCTL_CAPS0_DIFFIE_HELLMAN : 0) |
33 (IS_ENABLED(CONFIG_ASYMMETRIC_KEY_TYPE) ? KEYCTL_CAPS0_PUBLIC_KEY : 0) |
34 (IS_ENABLED(CONFIG_BIG_KEYS) ? KEYCTL_CAPS0_BIG_KEY : 0) |
35 KEYCTL_CAPS0_INVALIDATE |
36 KEYCTL_CAPS0_RESTRICT_KEYRING |
37 KEYCTL_CAPS0_MOVE
38 ),
39 [1] = (KEYCTL_CAPS1_NS_KEYRING_NAME |
40 KEYCTL_CAPS1_NS_KEY_TAG |
41 (IS_ENABLED(CONFIG_KEY_NOTIFICATIONS) ? KEYCTL_CAPS1_NOTIFICATIONS : 0)
42 ),
43};
44
45static int key_get_type_from_user(char *type,
46 const char __user *_type,
47 unsigned len)
48{
49 int ret;
50
51 ret = strncpy_from_user(type, _type, len);
52 if (ret < 0)
53 return ret;
54 if (ret == 0 || ret >= len)
55 return -EINVAL;
56 if (type[0] == '.')
57 return -EPERM;
58 type[len - 1] = '\0';
59 return 0;
60}
61
62/*
63 * Extract the description of a new key from userspace and either add it as a
64 * new key to the specified keyring or update a matching key in that keyring.
65 *
66 * If the description is NULL or an empty string, the key type is asked to
67 * generate one from the payload.
68 *
69 * The keyring must be writable so that we can attach the key to it.
70 *
71 * If successful, the new key's serial number is returned, otherwise an error
72 * code is returned.
73 */
74SYSCALL_DEFINE5(add_key, const char __user *, _type,
75 const char __user *, _description,
76 const void __user *, _payload,
77 size_t, plen,
78 key_serial_t, ringid)
79{
80 key_ref_t keyring_ref, key_ref;
81 char type[32], *description;
82 void *payload;
83 long ret;
84
85 ret = -EINVAL;
86 if (plen > 1024 * 1024 - 1)
87 goto error;
88
89 /* draw all the data into kernel space */
90 ret = key_get_type_from_user(type, _type, sizeof(type));
91 if (ret < 0)
92 goto error;
93
94 description = NULL;
95 if (_description) {
96 description = strndup_user(_description, KEY_MAX_DESC_SIZE);
97 if (IS_ERR(description)) {
98 ret = PTR_ERR(description);
99 goto error;
100 }
101 if (!*description) {
102 kfree(description);
103 description = NULL;
104 } else if ((description[0] == '.') &&
105 (strncmp(type, "keyring", 7) == 0)) {
106 ret = -EPERM;
107 goto error2;
108 }
109 }
110
111 /* pull the payload in if one was supplied */
112 payload = NULL;
113
114 if (plen) {
115 ret = -ENOMEM;
116 payload = kvmalloc(plen, GFP_KERNEL);
117 if (!payload)
118 goto error2;
119
120 ret = -EFAULT;
121 if (copy_from_user(payload, _payload, plen) != 0)
122 goto error3;
123 }
124
125 /* find the target keyring (which must be writable) */
126 keyring_ref = lookup_user_key(ringid, KEY_LOOKUP_CREATE, KEY_NEED_WRITE);
127 if (IS_ERR(keyring_ref)) {
128 ret = PTR_ERR(keyring_ref);
129 goto error3;
130 }
131
132 /* create or update the requested key and add it to the target
133 * keyring */
134 key_ref = key_create_or_update(keyring_ref, type, description,
135 payload, plen, KEY_PERM_UNDEF,
136 KEY_ALLOC_IN_QUOTA);
137 if (!IS_ERR(key_ref)) {
138 ret = key_ref_to_ptr(key_ref)->serial;
139 key_ref_put(key_ref);
140 }
141 else {
142 ret = PTR_ERR(key_ref);
143 }
144
145 key_ref_put(keyring_ref);
146 error3:
147 kvfree_sensitive(payload, plen);
148 error2:
149 kfree(description);
150 error:
151 return ret;
152}
153
154/*
155 * Search the process keyrings and keyring trees linked from those for a
156 * matching key. Keyrings must have appropriate Search permission to be
157 * searched.
158 *
159 * If a key is found, it will be attached to the destination keyring if there's
160 * one specified and the serial number of the key will be returned.
161 *
162 * If no key is found, /sbin/request-key will be invoked if _callout_info is
163 * non-NULL in an attempt to create a key. The _callout_info string will be
164 * passed to /sbin/request-key to aid with completing the request. If the
165 * _callout_info string is "" then it will be changed to "-".
166 */
167SYSCALL_DEFINE4(request_key, const char __user *, _type,
168 const char __user *, _description,
169 const char __user *, _callout_info,
170 key_serial_t, destringid)
171{
172 struct key_type *ktype;
173 struct key *key;
174 key_ref_t dest_ref;
175 size_t callout_len;
176 char type[32], *description, *callout_info;
177 long ret;
178
179 /* pull the type into kernel space */
180 ret = key_get_type_from_user(type, _type, sizeof(type));
181 if (ret < 0)
182 goto error;
183
184 /* pull the description into kernel space */
185 description = strndup_user(_description, KEY_MAX_DESC_SIZE);
186 if (IS_ERR(description)) {
187 ret = PTR_ERR(description);
188 goto error;
189 }
190
191 /* pull the callout info into kernel space */
192 callout_info = NULL;
193 callout_len = 0;
194 if (_callout_info) {
195 callout_info = strndup_user(_callout_info, PAGE_SIZE);
196 if (IS_ERR(callout_info)) {
197 ret = PTR_ERR(callout_info);
198 goto error2;
199 }
200 callout_len = strlen(callout_info);
201 }
202
203 /* get the destination keyring if specified */
204 dest_ref = NULL;
205 if (destringid) {
206 dest_ref = lookup_user_key(destringid, KEY_LOOKUP_CREATE,
207 KEY_NEED_WRITE);
208 if (IS_ERR(dest_ref)) {
209 ret = PTR_ERR(dest_ref);
210 goto error3;
211 }
212 }
213
214 /* find the key type */
215 ktype = key_type_lookup(type);
216 if (IS_ERR(ktype)) {
217 ret = PTR_ERR(ktype);
218 goto error4;
219 }
220
221 /* do the search */
222 key = request_key_and_link(ktype, description, NULL, callout_info,
223 callout_len, NULL, key_ref_to_ptr(dest_ref),
224 KEY_ALLOC_IN_QUOTA);
225 if (IS_ERR(key)) {
226 ret = PTR_ERR(key);
227 goto error5;
228 }
229
230 /* wait for the key to finish being constructed */
231 ret = wait_for_key_construction(key, 1);
232 if (ret < 0)
233 goto error6;
234
235 ret = key->serial;
236
237error6:
238 key_put(key);
239error5:
240 key_type_put(ktype);
241error4:
242 key_ref_put(dest_ref);
243error3:
244 kfree(callout_info);
245error2:
246 kfree(description);
247error:
248 return ret;
249}
250
251/*
252 * Get the ID of the specified process keyring.
253 *
254 * The requested keyring must have search permission to be found.
255 *
256 * If successful, the ID of the requested keyring will be returned.
257 */
258long keyctl_get_keyring_ID(key_serial_t id, int create)
259{
260 key_ref_t key_ref;
261 unsigned long lflags;
262 long ret;
263
264 lflags = create ? KEY_LOOKUP_CREATE : 0;
265 key_ref = lookup_user_key(id, lflags, KEY_NEED_SEARCH);
266 if (IS_ERR(key_ref)) {
267 ret = PTR_ERR(key_ref);
268 goto error;
269 }
270
271 ret = key_ref_to_ptr(key_ref)->serial;
272 key_ref_put(key_ref);
273error:
274 return ret;
275}
276
277/*
278 * Join a (named) session keyring.
279 *
280 * Create and join an anonymous session keyring or join a named session
281 * keyring, creating it if necessary. A named session keyring must have Search
282 * permission for it to be joined. Session keyrings without this permit will
283 * be skipped over. It is not permitted for userspace to create or join
284 * keyrings whose name begin with a dot.
285 *
286 * If successful, the ID of the joined session keyring will be returned.
287 */
288long keyctl_join_session_keyring(const char __user *_name)
289{
290 char *name;
291 long ret;
292
293 /* fetch the name from userspace */
294 name = NULL;
295 if (_name) {
296 name = strndup_user(_name, KEY_MAX_DESC_SIZE);
297 if (IS_ERR(name)) {
298 ret = PTR_ERR(name);
299 goto error;
300 }
301
302 ret = -EPERM;
303 if (name[0] == '.')
304 goto error_name;
305 }
306
307 /* join the session */
308 ret = join_session_keyring(name);
309error_name:
310 kfree(name);
311error:
312 return ret;
313}
314
315/*
316 * Update a key's data payload from the given data.
317 *
318 * The key must grant the caller Write permission and the key type must support
319 * updating for this to work. A negative key can be positively instantiated
320 * with this call.
321 *
322 * If successful, 0 will be returned. If the key type does not support
323 * updating, then -EOPNOTSUPP will be returned.
324 */
325long keyctl_update_key(key_serial_t id,
326 const void __user *_payload,
327 size_t plen)
328{
329 key_ref_t key_ref;
330 void *payload;
331 long ret;
332
333 ret = -EINVAL;
334 if (plen > PAGE_SIZE)
335 goto error;
336
337 /* pull the payload in if one was supplied */
338 payload = NULL;
339 if (plen) {
340 ret = -ENOMEM;
341 payload = kvmalloc(plen, GFP_KERNEL);
342 if (!payload)
343 goto error;
344
345 ret = -EFAULT;
346 if (copy_from_user(payload, _payload, plen) != 0)
347 goto error2;
348 }
349
350 /* find the target key (which must be writable) */
351 key_ref = lookup_user_key(id, 0, KEY_NEED_WRITE);
352 if (IS_ERR(key_ref)) {
353 ret = PTR_ERR(key_ref);
354 goto error2;
355 }
356
357 /* update the key */
358 ret = key_update(key_ref, payload, plen);
359
360 key_ref_put(key_ref);
361error2:
362 kvfree_sensitive(payload, plen);
363error:
364 return ret;
365}
366
367/*
368 * Revoke a key.
369 *
370 * The key must be grant the caller Write or Setattr permission for this to
371 * work. The key type should give up its quota claim when revoked. The key
372 * and any links to the key will be automatically garbage collected after a
373 * certain amount of time (/proc/sys/kernel/keys/gc_delay).
374 *
375 * Keys with KEY_FLAG_KEEP set should not be revoked.
376 *
377 * If successful, 0 is returned.
378 */
379long keyctl_revoke_key(key_serial_t id)
380{
381 key_ref_t key_ref;
382 struct key *key;
383 long ret;
384
385 key_ref = lookup_user_key(id, 0, KEY_NEED_WRITE);
386 if (IS_ERR(key_ref)) {
387 ret = PTR_ERR(key_ref);
388 if (ret != -EACCES)
389 goto error;
390 key_ref = lookup_user_key(id, 0, KEY_NEED_SETATTR);
391 if (IS_ERR(key_ref)) {
392 ret = PTR_ERR(key_ref);
393 goto error;
394 }
395 }
396
397 key = key_ref_to_ptr(key_ref);
398 ret = 0;
399 if (test_bit(KEY_FLAG_KEEP, &key->flags))
400 ret = -EPERM;
401 else
402 key_revoke(key);
403
404 key_ref_put(key_ref);
405error:
406 return ret;
407}
408
409/*
410 * Invalidate a key.
411 *
412 * The key must be grant the caller Invalidate permission for this to work.
413 * The key and any links to the key will be automatically garbage collected
414 * immediately.
415 *
416 * Keys with KEY_FLAG_KEEP set should not be invalidated.
417 *
418 * If successful, 0 is returned.
419 */
420long keyctl_invalidate_key(key_serial_t id)
421{
422 key_ref_t key_ref;
423 struct key *key;
424 long ret;
425
426 kenter("%d", id);
427
428 key_ref = lookup_user_key(id, 0, KEY_NEED_SEARCH);
429 if (IS_ERR(key_ref)) {
430 ret = PTR_ERR(key_ref);
431
432 /* Root is permitted to invalidate certain special keys */
433 if (capable(CAP_SYS_ADMIN)) {
434 key_ref = lookup_user_key(id, 0, KEY_SYSADMIN_OVERRIDE);
435 if (IS_ERR(key_ref))
436 goto error;
437 if (test_bit(KEY_FLAG_ROOT_CAN_INVAL,
438 &key_ref_to_ptr(key_ref)->flags))
439 goto invalidate;
440 goto error_put;
441 }
442
443 goto error;
444 }
445
446invalidate:
447 key = key_ref_to_ptr(key_ref);
448 ret = 0;
449 if (test_bit(KEY_FLAG_KEEP, &key->flags))
450 ret = -EPERM;
451 else
452 key_invalidate(key);
453error_put:
454 key_ref_put(key_ref);
455error:
456 kleave(" = %ld", ret);
457 return ret;
458}
459
460/*
461 * Clear the specified keyring, creating an empty process keyring if one of the
462 * special keyring IDs is used.
463 *
464 * The keyring must grant the caller Write permission and not have
465 * KEY_FLAG_KEEP set for this to work. If successful, 0 will be returned.
466 */
467long keyctl_keyring_clear(key_serial_t ringid)
468{
469 key_ref_t keyring_ref;
470 struct key *keyring;
471 long ret;
472
473 keyring_ref = lookup_user_key(ringid, KEY_LOOKUP_CREATE, KEY_NEED_WRITE);
474 if (IS_ERR(keyring_ref)) {
475 ret = PTR_ERR(keyring_ref);
476
477 /* Root is permitted to invalidate certain special keyrings */
478 if (capable(CAP_SYS_ADMIN)) {
479 keyring_ref = lookup_user_key(ringid, 0,
480 KEY_SYSADMIN_OVERRIDE);
481 if (IS_ERR(keyring_ref))
482 goto error;
483 if (test_bit(KEY_FLAG_ROOT_CAN_CLEAR,
484 &key_ref_to_ptr(keyring_ref)->flags))
485 goto clear;
486 goto error_put;
487 }
488
489 goto error;
490 }
491
492clear:
493 keyring = key_ref_to_ptr(keyring_ref);
494 if (test_bit(KEY_FLAG_KEEP, &keyring->flags))
495 ret = -EPERM;
496 else
497 ret = keyring_clear(keyring);
498error_put:
499 key_ref_put(keyring_ref);
500error:
501 return ret;
502}
503
504/*
505 * Create a link from a keyring to a key if there's no matching key in the
506 * keyring, otherwise replace the link to the matching key with a link to the
507 * new key.
508 *
509 * The key must grant the caller Link permission and the keyring must grant
510 * the caller Write permission. Furthermore, if an additional link is created,
511 * the keyring's quota will be extended.
512 *
513 * If successful, 0 will be returned.
514 */
515long keyctl_keyring_link(key_serial_t id, key_serial_t ringid)
516{
517 key_ref_t keyring_ref, key_ref;
518 long ret;
519
520 keyring_ref = lookup_user_key(ringid, KEY_LOOKUP_CREATE, KEY_NEED_WRITE);
521 if (IS_ERR(keyring_ref)) {
522 ret = PTR_ERR(keyring_ref);
523 goto error;
524 }
525
526 key_ref = lookup_user_key(id, KEY_LOOKUP_CREATE, KEY_NEED_LINK);
527 if (IS_ERR(key_ref)) {
528 ret = PTR_ERR(key_ref);
529 goto error2;
530 }
531
532 ret = key_link(key_ref_to_ptr(keyring_ref), key_ref_to_ptr(key_ref));
533
534 key_ref_put(key_ref);
535error2:
536 key_ref_put(keyring_ref);
537error:
538 return ret;
539}
540
541/*
542 * Unlink a key from a keyring.
543 *
544 * The keyring must grant the caller Write permission for this to work; the key
545 * itself need not grant the caller anything. If the last link to a key is
546 * removed then that key will be scheduled for destruction.
547 *
548 * Keys or keyrings with KEY_FLAG_KEEP set should not be unlinked.
549 *
550 * If successful, 0 will be returned.
551 */
552long keyctl_keyring_unlink(key_serial_t id, key_serial_t ringid)
553{
554 key_ref_t keyring_ref, key_ref;
555 struct key *keyring, *key;
556 long ret;
557
558 keyring_ref = lookup_user_key(ringid, 0, KEY_NEED_WRITE);
559 if (IS_ERR(keyring_ref)) {
560 ret = PTR_ERR(keyring_ref);
561 goto error;
562 }
563
564 key_ref = lookup_user_key(id, KEY_LOOKUP_PARTIAL, KEY_NEED_UNLINK);
565 if (IS_ERR(key_ref)) {
566 ret = PTR_ERR(key_ref);
567 goto error2;
568 }
569
570 keyring = key_ref_to_ptr(keyring_ref);
571 key = key_ref_to_ptr(key_ref);
572 if (test_bit(KEY_FLAG_KEEP, &keyring->flags) &&
573 test_bit(KEY_FLAG_KEEP, &key->flags))
574 ret = -EPERM;
575 else
576 ret = key_unlink(keyring, key);
577
578 key_ref_put(key_ref);
579error2:
580 key_ref_put(keyring_ref);
581error:
582 return ret;
583}
584
585/*
586 * Move a link to a key from one keyring to another, displacing any matching
587 * key from the destination keyring.
588 *
589 * The key must grant the caller Link permission and both keyrings must grant
590 * the caller Write permission. There must also be a link in the from keyring
591 * to the key. If both keyrings are the same, nothing is done.
592 *
593 * If successful, 0 will be returned.
594 */
595long keyctl_keyring_move(key_serial_t id, key_serial_t from_ringid,
596 key_serial_t to_ringid, unsigned int flags)
597{
598 key_ref_t key_ref, from_ref, to_ref;
599 long ret;
600
601 if (flags & ~KEYCTL_MOVE_EXCL)
602 return -EINVAL;
603
604 key_ref = lookup_user_key(id, KEY_LOOKUP_CREATE, KEY_NEED_LINK);
605 if (IS_ERR(key_ref))
606 return PTR_ERR(key_ref);
607
608 from_ref = lookup_user_key(from_ringid, 0, KEY_NEED_WRITE);
609 if (IS_ERR(from_ref)) {
610 ret = PTR_ERR(from_ref);
611 goto error2;
612 }
613
614 to_ref = lookup_user_key(to_ringid, KEY_LOOKUP_CREATE, KEY_NEED_WRITE);
615 if (IS_ERR(to_ref)) {
616 ret = PTR_ERR(to_ref);
617 goto error3;
618 }
619
620 ret = key_move(key_ref_to_ptr(key_ref), key_ref_to_ptr(from_ref),
621 key_ref_to_ptr(to_ref), flags);
622
623 key_ref_put(to_ref);
624error3:
625 key_ref_put(from_ref);
626error2:
627 key_ref_put(key_ref);
628 return ret;
629}
630
631/*
632 * Return a description of a key to userspace.
633 *
634 * The key must grant the caller View permission for this to work.
635 *
636 * If there's a buffer, we place up to buflen bytes of data into it formatted
637 * in the following way:
638 *
639 * type;uid;gid;perm;description<NUL>
640 *
641 * If successful, we return the amount of description available, irrespective
642 * of how much we may have copied into the buffer.
643 */
644long keyctl_describe_key(key_serial_t keyid,
645 char __user *buffer,
646 size_t buflen)
647{
648 struct key *key, *instkey;
649 key_ref_t key_ref;
650 char *infobuf;
651 long ret;
652 int desclen, infolen;
653
654 key_ref = lookup_user_key(keyid, KEY_LOOKUP_PARTIAL, KEY_NEED_VIEW);
655 if (IS_ERR(key_ref)) {
656 /* viewing a key under construction is permitted if we have the
657 * authorisation token handy */
658 if (PTR_ERR(key_ref) == -EACCES) {
659 instkey = key_get_instantiation_authkey(keyid);
660 if (!IS_ERR(instkey)) {
661 key_put(instkey);
662 key_ref = lookup_user_key(keyid,
663 KEY_LOOKUP_PARTIAL,
664 KEY_AUTHTOKEN_OVERRIDE);
665 if (!IS_ERR(key_ref))
666 goto okay;
667 }
668 }
669
670 ret = PTR_ERR(key_ref);
671 goto error;
672 }
673
674okay:
675 key = key_ref_to_ptr(key_ref);
676 desclen = strlen(key->description);
677
678 /* calculate how much information we're going to return */
679 ret = -ENOMEM;
680 infobuf = kasprintf(GFP_KERNEL,
681 "%s;%d;%d;%08x;",
682 key->type->name,
683 from_kuid_munged(current_user_ns(), key->uid),
684 from_kgid_munged(current_user_ns(), key->gid),
685 key->perm);
686 if (!infobuf)
687 goto error2;
688 infolen = strlen(infobuf);
689 ret = infolen + desclen + 1;
690
691 /* consider returning the data */
692 if (buffer && buflen >= ret) {
693 if (copy_to_user(buffer, infobuf, infolen) != 0 ||
694 copy_to_user(buffer + infolen, key->description,
695 desclen + 1) != 0)
696 ret = -EFAULT;
697 }
698
699 kfree(infobuf);
700error2:
701 key_ref_put(key_ref);
702error:
703 return ret;
704}
705
706/*
707 * Search the specified keyring and any keyrings it links to for a matching
708 * key. Only keyrings that grant the caller Search permission will be searched
709 * (this includes the starting keyring). Only keys with Search permission can
710 * be found.
711 *
712 * If successful, the found key will be linked to the destination keyring if
713 * supplied and the key has Link permission, and the found key ID will be
714 * returned.
715 */
716long keyctl_keyring_search(key_serial_t ringid,
717 const char __user *_type,
718 const char __user *_description,
719 key_serial_t destringid)
720{
721 struct key_type *ktype;
722 key_ref_t keyring_ref, key_ref, dest_ref;
723 char type[32], *description;
724 long ret;
725
726 /* pull the type and description into kernel space */
727 ret = key_get_type_from_user(type, _type, sizeof(type));
728 if (ret < 0)
729 goto error;
730
731 description = strndup_user(_description, KEY_MAX_DESC_SIZE);
732 if (IS_ERR(description)) {
733 ret = PTR_ERR(description);
734 goto error;
735 }
736
737 /* get the keyring at which to begin the search */
738 keyring_ref = lookup_user_key(ringid, 0, KEY_NEED_SEARCH);
739 if (IS_ERR(keyring_ref)) {
740 ret = PTR_ERR(keyring_ref);
741 goto error2;
742 }
743
744 /* get the destination keyring if specified */
745 dest_ref = NULL;
746 if (destringid) {
747 dest_ref = lookup_user_key(destringid, KEY_LOOKUP_CREATE,
748 KEY_NEED_WRITE);
749 if (IS_ERR(dest_ref)) {
750 ret = PTR_ERR(dest_ref);
751 goto error3;
752 }
753 }
754
755 /* find the key type */
756 ktype = key_type_lookup(type);
757 if (IS_ERR(ktype)) {
758 ret = PTR_ERR(ktype);
759 goto error4;
760 }
761
762 /* do the search */
763 key_ref = keyring_search(keyring_ref, ktype, description, true);
764 if (IS_ERR(key_ref)) {
765 ret = PTR_ERR(key_ref);
766
767 /* treat lack or presence of a negative key the same */
768 if (ret == -EAGAIN)
769 ret = -ENOKEY;
770 goto error5;
771 }
772
773 /* link the resulting key to the destination keyring if we can */
774 if (dest_ref) {
775 ret = key_permission(key_ref, KEY_NEED_LINK);
776 if (ret < 0)
777 goto error6;
778
779 ret = key_link(key_ref_to_ptr(dest_ref), key_ref_to_ptr(key_ref));
780 if (ret < 0)
781 goto error6;
782 }
783
784 ret = key_ref_to_ptr(key_ref)->serial;
785
786error6:
787 key_ref_put(key_ref);
788error5:
789 key_type_put(ktype);
790error4:
791 key_ref_put(dest_ref);
792error3:
793 key_ref_put(keyring_ref);
794error2:
795 kfree(description);
796error:
797 return ret;
798}
799
800/*
801 * Call the read method
802 */
803static long __keyctl_read_key(struct key *key, char *buffer, size_t buflen)
804{
805 long ret;
806
807 down_read(&key->sem);
808 ret = key_validate(key);
809 if (ret == 0)
810 ret = key->type->read(key, buffer, buflen);
811 up_read(&key->sem);
812 return ret;
813}
814
815/*
816 * Read a key's payload.
817 *
818 * The key must either grant the caller Read permission, or it must grant the
819 * caller Search permission when searched for from the process keyrings.
820 *
821 * If successful, we place up to buflen bytes of data into the buffer, if one
822 * is provided, and return the amount of data that is available in the key,
823 * irrespective of how much we copied into the buffer.
824 */
825long keyctl_read_key(key_serial_t keyid, char __user *buffer, size_t buflen)
826{
827 struct key *key;
828 key_ref_t key_ref;
829 long ret;
830 char *key_data = NULL;
831 size_t key_data_len;
832
833 /* find the key first */
834 key_ref = lookup_user_key(keyid, 0, KEY_DEFER_PERM_CHECK);
835 if (IS_ERR(key_ref)) {
836 ret = -ENOKEY;
837 goto out;
838 }
839
840 key = key_ref_to_ptr(key_ref);
841
842 ret = key_read_state(key);
843 if (ret < 0)
844 goto key_put_out; /* Negatively instantiated */
845
846 /* see if we can read it directly */
847 ret = key_permission(key_ref, KEY_NEED_READ);
848 if (ret == 0)
849 goto can_read_key;
850 if (ret != -EACCES)
851 goto key_put_out;
852
853 /* we can't; see if it's searchable from this process's keyrings
854 * - we automatically take account of the fact that it may be
855 * dangling off an instantiation key
856 */
857 if (!is_key_possessed(key_ref)) {
858 ret = -EACCES;
859 goto key_put_out;
860 }
861
862 /* the key is probably readable - now try to read it */
863can_read_key:
864 if (!key->type->read) {
865 ret = -EOPNOTSUPP;
866 goto key_put_out;
867 }
868
869 if (!buffer || !buflen) {
870 /* Get the key length from the read method */
871 ret = __keyctl_read_key(key, NULL, 0);
872 goto key_put_out;
873 }
874
875 /*
876 * Read the data with the semaphore held (since we might sleep)
877 * to protect against the key being updated or revoked.
878 *
879 * Allocating a temporary buffer to hold the keys before
880 * transferring them to user buffer to avoid potential
881 * deadlock involving page fault and mmap_lock.
882 *
883 * key_data_len = (buflen <= PAGE_SIZE)
884 * ? buflen : actual length of key data
885 *
886 * This prevents allocating arbitrary large buffer which can
887 * be much larger than the actual key length. In the latter case,
888 * at least 2 passes of this loop is required.
889 */
890 key_data_len = (buflen <= PAGE_SIZE) ? buflen : 0;
891 for (;;) {
892 if (key_data_len) {
893 key_data = kvmalloc(key_data_len, GFP_KERNEL);
894 if (!key_data) {
895 ret = -ENOMEM;
896 goto key_put_out;
897 }
898 }
899
900 ret = __keyctl_read_key(key, key_data, key_data_len);
901
902 /*
903 * Read methods will just return the required length without
904 * any copying if the provided length isn't large enough.
905 */
906 if (ret <= 0 || ret > buflen)
907 break;
908
909 /*
910 * The key may change (unlikely) in between 2 consecutive
911 * __keyctl_read_key() calls. In this case, we reallocate
912 * a larger buffer and redo the key read when
913 * key_data_len < ret <= buflen.
914 */
915 if (ret > key_data_len) {
916 if (unlikely(key_data))
917 kvfree_sensitive(key_data, key_data_len);
918 key_data_len = ret;
919 continue; /* Allocate buffer */
920 }
921
922 if (copy_to_user(buffer, key_data, ret))
923 ret = -EFAULT;
924 break;
925 }
926 kvfree_sensitive(key_data, key_data_len);
927
928key_put_out:
929 key_put(key);
930out:
931 return ret;
932}
933
934/*
935 * Change the ownership of 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. For the UID to be changed, or
939 * for the GID to be changed to a group the caller is not a member of, the
940 * caller must have sysadmin capability. If either uid or gid is -1 then that
941 * attribute is not changed.
942 *
943 * If the UID is to be changed, the new user must have sufficient quota to
944 * accept the key. The quota deduction will be removed from the old user to
945 * the new user should the attribute be changed.
946 *
947 * If successful, 0 will be returned.
948 */
949long keyctl_chown_key(key_serial_t id, uid_t user, gid_t group)
950{
951 struct key_user *newowner, *zapowner = NULL;
952 struct key *key;
953 key_ref_t key_ref;
954 long ret;
955 kuid_t uid;
956 kgid_t gid;
957
958 uid = make_kuid(current_user_ns(), user);
959 gid = make_kgid(current_user_ns(), group);
960 ret = -EINVAL;
961 if ((user != (uid_t) -1) && !uid_valid(uid))
962 goto error;
963 if ((group != (gid_t) -1) && !gid_valid(gid))
964 goto error;
965
966 ret = 0;
967 if (user == (uid_t) -1 && group == (gid_t) -1)
968 goto error;
969
970 key_ref = lookup_user_key(id, KEY_LOOKUP_CREATE | KEY_LOOKUP_PARTIAL,
971 KEY_NEED_SETATTR);
972 if (IS_ERR(key_ref)) {
973 ret = PTR_ERR(key_ref);
974 goto error;
975 }
976
977 key = key_ref_to_ptr(key_ref);
978
979 /* make the changes with the locks held to prevent chown/chown races */
980 ret = -EACCES;
981 down_write(&key->sem);
982
983 if (!capable(CAP_SYS_ADMIN)) {
984 /* only the sysadmin can chown a key to some other UID */
985 if (user != (uid_t) -1 && !uid_eq(key->uid, uid))
986 goto error_put;
987
988 /* only the sysadmin can set the key's GID to a group other
989 * than one of those that the current process subscribes to */
990 if (group != (gid_t) -1 && !gid_eq(gid, key->gid) && !in_group_p(gid))
991 goto error_put;
992 }
993
994 /* change the UID */
995 if (user != (uid_t) -1 && !uid_eq(uid, key->uid)) {
996 ret = -ENOMEM;
997 newowner = key_user_lookup(uid);
998 if (!newowner)
999 goto error_put;
1000
1001 /* transfer the quota burden to the new user */
1002 if (test_bit(KEY_FLAG_IN_QUOTA, &key->flags)) {
1003 unsigned maxkeys = uid_eq(uid, GLOBAL_ROOT_UID) ?
1004 key_quota_root_maxkeys : key_quota_maxkeys;
1005 unsigned maxbytes = uid_eq(uid, GLOBAL_ROOT_UID) ?
1006 key_quota_root_maxbytes : key_quota_maxbytes;
1007
1008 spin_lock(&newowner->lock);
1009 if (newowner->qnkeys + 1 > maxkeys ||
1010 newowner->qnbytes + key->quotalen > maxbytes ||
1011 newowner->qnbytes + key->quotalen <
1012 newowner->qnbytes)
1013 goto quota_overrun;
1014
1015 newowner->qnkeys++;
1016 newowner->qnbytes += key->quotalen;
1017 spin_unlock(&newowner->lock);
1018
1019 spin_lock(&key->user->lock);
1020 key->user->qnkeys--;
1021 key->user->qnbytes -= key->quotalen;
1022 spin_unlock(&key->user->lock);
1023 }
1024
1025 atomic_dec(&key->user->nkeys);
1026 atomic_inc(&newowner->nkeys);
1027
1028 if (key->state != KEY_IS_UNINSTANTIATED) {
1029 atomic_dec(&key->user->nikeys);
1030 atomic_inc(&newowner->nikeys);
1031 }
1032
1033 zapowner = key->user;
1034 key->user = newowner;
1035 key->uid = uid;
1036 }
1037
1038 /* change the GID */
1039 if (group != (gid_t) -1)
1040 key->gid = gid;
1041
1042 notify_key(key, NOTIFY_KEY_SETATTR, 0);
1043 ret = 0;
1044
1045error_put:
1046 up_write(&key->sem);
1047 key_put(key);
1048 if (zapowner)
1049 key_user_put(zapowner);
1050error:
1051 return ret;
1052
1053quota_overrun:
1054 spin_unlock(&newowner->lock);
1055 zapowner = newowner;
1056 ret = -EDQUOT;
1057 goto error_put;
1058}
1059
1060/*
1061 * Change the permission mask on a key.
1062 *
1063 * The key must grant the caller Setattr permission for this to work, though
1064 * the key need not be fully instantiated yet. If the caller does not have
1065 * sysadmin capability, it may only change the permission on keys that it owns.
1066 */
1067long keyctl_setperm_key(key_serial_t id, key_perm_t perm)
1068{
1069 struct key *key;
1070 key_ref_t key_ref;
1071 long ret;
1072
1073 ret = -EINVAL;
1074 if (perm & ~(KEY_POS_ALL | KEY_USR_ALL | KEY_GRP_ALL | KEY_OTH_ALL))
1075 goto error;
1076
1077 key_ref = lookup_user_key(id, KEY_LOOKUP_CREATE | KEY_LOOKUP_PARTIAL,
1078 KEY_NEED_SETATTR);
1079 if (IS_ERR(key_ref)) {
1080 ret = PTR_ERR(key_ref);
1081 goto error;
1082 }
1083
1084 key = key_ref_to_ptr(key_ref);
1085
1086 /* make the changes with the locks held to prevent chown/chmod races */
1087 ret = -EACCES;
1088 down_write(&key->sem);
1089
1090 /* if we're not the sysadmin, we can only change a key that we own */
1091 if (capable(CAP_SYS_ADMIN) || uid_eq(key->uid, current_fsuid())) {
1092 key->perm = perm;
1093 notify_key(key, NOTIFY_KEY_SETATTR, 0);
1094 ret = 0;
1095 }
1096
1097 up_write(&key->sem);
1098 key_put(key);
1099error:
1100 return ret;
1101}
1102
1103/*
1104 * Get the destination keyring for instantiation and check that the caller has
1105 * Write permission on it.
1106 */
1107static long get_instantiation_keyring(key_serial_t ringid,
1108 struct request_key_auth *rka,
1109 struct key **_dest_keyring)
1110{
1111 key_ref_t dkref;
1112
1113 *_dest_keyring = NULL;
1114
1115 /* just return a NULL pointer if we weren't asked to make a link */
1116 if (ringid == 0)
1117 return 0;
1118
1119 /* if a specific keyring is nominated by ID, then use that */
1120 if (ringid > 0) {
1121 dkref = lookup_user_key(ringid, KEY_LOOKUP_CREATE, KEY_NEED_WRITE);
1122 if (IS_ERR(dkref))
1123 return PTR_ERR(dkref);
1124 *_dest_keyring = key_ref_to_ptr(dkref);
1125 return 0;
1126 }
1127
1128 if (ringid == KEY_SPEC_REQKEY_AUTH_KEY)
1129 return -EINVAL;
1130
1131 /* otherwise specify the destination keyring recorded in the
1132 * authorisation key (any KEY_SPEC_*_KEYRING) */
1133 if (ringid >= KEY_SPEC_REQUESTOR_KEYRING) {
1134 *_dest_keyring = key_get(rka->dest_keyring);
1135 return 0;
1136 }
1137
1138 return -ENOKEY;
1139}
1140
1141/*
1142 * Change the request_key authorisation key on the current process.
1143 */
1144static int keyctl_change_reqkey_auth(struct key *key)
1145{
1146 struct cred *new;
1147
1148 new = prepare_creds();
1149 if (!new)
1150 return -ENOMEM;
1151
1152 key_put(new->request_key_auth);
1153 new->request_key_auth = key_get(key);
1154
1155 return commit_creds(new);
1156}
1157
1158/*
1159 * Instantiate a key with the specified payload and link the key into the
1160 * destination keyring if one is given.
1161 *
1162 * The caller must have the appropriate instantiation permit set for this to
1163 * work (see keyctl_assume_authority). No other permissions are required.
1164 *
1165 * If successful, 0 will be returned.
1166 */
1167static long keyctl_instantiate_key_common(key_serial_t id,
1168 struct iov_iter *from,
1169 key_serial_t ringid)
1170{
1171 const struct cred *cred = current_cred();
1172 struct request_key_auth *rka;
1173 struct key *instkey, *dest_keyring;
1174 size_t plen = from ? iov_iter_count(from) : 0;
1175 void *payload;
1176 long ret;
1177
1178 kenter("%d,,%zu,%d", id, plen, ringid);
1179
1180 if (!plen)
1181 from = NULL;
1182
1183 ret = -EINVAL;
1184 if (plen > 1024 * 1024 - 1)
1185 goto error;
1186
1187 /* the appropriate instantiation authorisation key must have been
1188 * assumed before calling this */
1189 ret = -EPERM;
1190 instkey = cred->request_key_auth;
1191 if (!instkey)
1192 goto error;
1193
1194 rka = instkey->payload.data[0];
1195 if (rka->target_key->serial != id)
1196 goto error;
1197
1198 /* pull the payload in if one was supplied */
1199 payload = NULL;
1200
1201 if (from) {
1202 ret = -ENOMEM;
1203 payload = kvmalloc(plen, GFP_KERNEL);
1204 if (!payload)
1205 goto error;
1206
1207 ret = -EFAULT;
1208 if (!copy_from_iter_full(payload, plen, from))
1209 goto error2;
1210 }
1211
1212 /* find the destination keyring amongst those belonging to the
1213 * requesting task */
1214 ret = get_instantiation_keyring(ringid, rka, &dest_keyring);
1215 if (ret < 0)
1216 goto error2;
1217
1218 /* instantiate the key and link it into a keyring */
1219 ret = key_instantiate_and_link(rka->target_key, payload, plen,
1220 dest_keyring, instkey);
1221
1222 key_put(dest_keyring);
1223
1224 /* discard the assumed authority if it's just been disabled by
1225 * instantiation of the key */
1226 if (ret == 0)
1227 keyctl_change_reqkey_auth(NULL);
1228
1229error2:
1230 kvfree_sensitive(payload, plen);
1231error:
1232 return ret;
1233}
1234
1235/*
1236 * Instantiate a key with the specified payload and link the key into the
1237 * destination keyring if one is given.
1238 *
1239 * The caller must have the appropriate instantiation permit set for this to
1240 * work (see keyctl_assume_authority). No other permissions are required.
1241 *
1242 * If successful, 0 will be returned.
1243 */
1244long keyctl_instantiate_key(key_serial_t id,
1245 const void __user *_payload,
1246 size_t plen,
1247 key_serial_t ringid)
1248{
1249 if (_payload && plen) {
1250 struct iovec iov;
1251 struct iov_iter from;
1252 int ret;
1253
1254 ret = import_single_range(ITER_SOURCE, (void __user *)_payload, plen,
1255 &iov, &from);
1256 if (unlikely(ret))
1257 return ret;
1258
1259 return keyctl_instantiate_key_common(id, &from, ringid);
1260 }
1261
1262 return keyctl_instantiate_key_common(id, NULL, ringid);
1263}
1264
1265/*
1266 * Instantiate a key with the specified multipart payload and link the key into
1267 * the destination keyring if one is given.
1268 *
1269 * The caller must have the appropriate instantiation permit set for this to
1270 * work (see keyctl_assume_authority). No other permissions are required.
1271 *
1272 * If successful, 0 will be returned.
1273 */
1274long keyctl_instantiate_key_iov(key_serial_t id,
1275 const struct iovec __user *_payload_iov,
1276 unsigned ioc,
1277 key_serial_t ringid)
1278{
1279 struct iovec iovstack[UIO_FASTIOV], *iov = iovstack;
1280 struct iov_iter from;
1281 long ret;
1282
1283 if (!_payload_iov)
1284 ioc = 0;
1285
1286 ret = import_iovec(ITER_SOURCE, _payload_iov, ioc,
1287 ARRAY_SIZE(iovstack), &iov, &from);
1288 if (ret < 0)
1289 return ret;
1290 ret = keyctl_instantiate_key_common(id, &from, ringid);
1291 kfree(iov);
1292 return ret;
1293}
1294
1295/*
1296 * Negatively instantiate the key with the given timeout (in seconds) and link
1297 * the key into the destination keyring if one is given.
1298 *
1299 * The caller must have the appropriate instantiation permit set for this to
1300 * work (see keyctl_assume_authority). No other permissions are required.
1301 *
1302 * The key and any links to the key will be automatically garbage collected
1303 * after the timeout expires.
1304 *
1305 * Negative keys are used to rate limit repeated request_key() calls by causing
1306 * them to return -ENOKEY until the negative key expires.
1307 *
1308 * If successful, 0 will be returned.
1309 */
1310long keyctl_negate_key(key_serial_t id, unsigned timeout, key_serial_t ringid)
1311{
1312 return keyctl_reject_key(id, timeout, ENOKEY, ringid);
1313}
1314
1315/*
1316 * Negatively instantiate the key with the given timeout (in seconds) and error
1317 * code and link the key into the destination keyring if one is given.
1318 *
1319 * The caller must have the appropriate instantiation permit set for this to
1320 * work (see keyctl_assume_authority). No other permissions are required.
1321 *
1322 * The key and any links to the key will be automatically garbage collected
1323 * after the timeout expires.
1324 *
1325 * Negative keys are used to rate limit repeated request_key() calls by causing
1326 * them to return the specified error code until the negative key expires.
1327 *
1328 * If successful, 0 will be returned.
1329 */
1330long keyctl_reject_key(key_serial_t id, unsigned timeout, unsigned error,
1331 key_serial_t ringid)
1332{
1333 const struct cred *cred = current_cred();
1334 struct request_key_auth *rka;
1335 struct key *instkey, *dest_keyring;
1336 long ret;
1337
1338 kenter("%d,%u,%u,%d", id, timeout, error, ringid);
1339
1340 /* must be a valid error code and mustn't be a kernel special */
1341 if (error <= 0 ||
1342 error >= MAX_ERRNO ||
1343 error == ERESTARTSYS ||
1344 error == ERESTARTNOINTR ||
1345 error == ERESTARTNOHAND ||
1346 error == ERESTART_RESTARTBLOCK)
1347 return -EINVAL;
1348
1349 /* the appropriate instantiation authorisation key must have been
1350 * assumed before calling this */
1351 ret = -EPERM;
1352 instkey = cred->request_key_auth;
1353 if (!instkey)
1354 goto error;
1355
1356 rka = instkey->payload.data[0];
1357 if (rka->target_key->serial != id)
1358 goto error;
1359
1360 /* find the destination keyring if present (which must also be
1361 * writable) */
1362 ret = get_instantiation_keyring(ringid, rka, &dest_keyring);
1363 if (ret < 0)
1364 goto error;
1365
1366 /* instantiate the key and link it into a keyring */
1367 ret = key_reject_and_link(rka->target_key, timeout, error,
1368 dest_keyring, instkey);
1369
1370 key_put(dest_keyring);
1371
1372 /* discard the assumed authority if it's just been disabled by
1373 * instantiation of the key */
1374 if (ret == 0)
1375 keyctl_change_reqkey_auth(NULL);
1376
1377error:
1378 return ret;
1379}
1380
1381/*
1382 * Read or set the default keyring in which request_key() will cache keys and
1383 * return the old setting.
1384 *
1385 * If a thread or process keyring is specified then it will be created if it
1386 * doesn't yet exist. The old setting will be returned if successful.
1387 */
1388long keyctl_set_reqkey_keyring(int reqkey_defl)
1389{
1390 struct cred *new;
1391 int ret, old_setting;
1392
1393 old_setting = current_cred_xxx(jit_keyring);
1394
1395 if (reqkey_defl == KEY_REQKEY_DEFL_NO_CHANGE)
1396 return old_setting;
1397
1398 new = prepare_creds();
1399 if (!new)
1400 return -ENOMEM;
1401
1402 switch (reqkey_defl) {
1403 case KEY_REQKEY_DEFL_THREAD_KEYRING:
1404 ret = install_thread_keyring_to_cred(new);
1405 if (ret < 0)
1406 goto error;
1407 goto set;
1408
1409 case KEY_REQKEY_DEFL_PROCESS_KEYRING:
1410 ret = install_process_keyring_to_cred(new);
1411 if (ret < 0)
1412 goto error;
1413 goto set;
1414
1415 case KEY_REQKEY_DEFL_DEFAULT:
1416 case KEY_REQKEY_DEFL_SESSION_KEYRING:
1417 case KEY_REQKEY_DEFL_USER_KEYRING:
1418 case KEY_REQKEY_DEFL_USER_SESSION_KEYRING:
1419 case KEY_REQKEY_DEFL_REQUESTOR_KEYRING:
1420 goto set;
1421
1422 case KEY_REQKEY_DEFL_NO_CHANGE:
1423 case KEY_REQKEY_DEFL_GROUP_KEYRING:
1424 default:
1425 ret = -EINVAL;
1426 goto error;
1427 }
1428
1429set:
1430 new->jit_keyring = reqkey_defl;
1431 commit_creds(new);
1432 return old_setting;
1433error:
1434 abort_creds(new);
1435 return ret;
1436}
1437
1438/*
1439 * Set or clear the timeout on a key.
1440 *
1441 * Either the key must grant the caller Setattr permission or else the caller
1442 * must hold an instantiation authorisation token for the key.
1443 *
1444 * The timeout is either 0 to clear the timeout, or a number of seconds from
1445 * the current time. The key and any links to the key will be automatically
1446 * garbage collected after the timeout expires.
1447 *
1448 * Keys with KEY_FLAG_KEEP set should not be timed out.
1449 *
1450 * If successful, 0 is returned.
1451 */
1452long keyctl_set_timeout(key_serial_t id, unsigned timeout)
1453{
1454 struct key *key, *instkey;
1455 key_ref_t key_ref;
1456 long ret;
1457
1458 key_ref = lookup_user_key(id, KEY_LOOKUP_CREATE | KEY_LOOKUP_PARTIAL,
1459 KEY_NEED_SETATTR);
1460 if (IS_ERR(key_ref)) {
1461 /* setting the timeout on a key under construction is permitted
1462 * if we have the authorisation token handy */
1463 if (PTR_ERR(key_ref) == -EACCES) {
1464 instkey = key_get_instantiation_authkey(id);
1465 if (!IS_ERR(instkey)) {
1466 key_put(instkey);
1467 key_ref = lookup_user_key(id,
1468 KEY_LOOKUP_PARTIAL,
1469 KEY_AUTHTOKEN_OVERRIDE);
1470 if (!IS_ERR(key_ref))
1471 goto okay;
1472 }
1473 }
1474
1475 ret = PTR_ERR(key_ref);
1476 goto error;
1477 }
1478
1479okay:
1480 key = key_ref_to_ptr(key_ref);
1481 ret = 0;
1482 if (test_bit(KEY_FLAG_KEEP, &key->flags)) {
1483 ret = -EPERM;
1484 } else {
1485 key_set_timeout(key, timeout);
1486 notify_key(key, NOTIFY_KEY_SETATTR, 0);
1487 }
1488 key_put(key);
1489
1490error:
1491 return ret;
1492}
1493
1494/*
1495 * Assume (or clear) the authority to instantiate the specified key.
1496 *
1497 * This sets the authoritative token currently in force for key instantiation.
1498 * This must be done for a key to be instantiated. It has the effect of making
1499 * available all the keys from the caller of the request_key() that created a
1500 * key to request_key() calls made by the caller of this function.
1501 *
1502 * The caller must have the instantiation key in their process keyrings with a
1503 * Search permission grant available to the caller.
1504 *
1505 * If the ID given is 0, then the setting will be cleared and 0 returned.
1506 *
1507 * If the ID given has a matching an authorisation key, then that key will be
1508 * set and its ID will be returned. The authorisation key can be read to get
1509 * the callout information passed to request_key().
1510 */
1511long keyctl_assume_authority(key_serial_t id)
1512{
1513 struct key *authkey;
1514 long ret;
1515
1516 /* special key IDs aren't permitted */
1517 ret = -EINVAL;
1518 if (id < 0)
1519 goto error;
1520
1521 /* we divest ourselves of authority if given an ID of 0 */
1522 if (id == 0) {
1523 ret = keyctl_change_reqkey_auth(NULL);
1524 goto error;
1525 }
1526
1527 /* attempt to assume the authority temporarily granted to us whilst we
1528 * instantiate the specified key
1529 * - the authorisation key must be in the current task's keyrings
1530 * somewhere
1531 */
1532 authkey = key_get_instantiation_authkey(id);
1533 if (IS_ERR(authkey)) {
1534 ret = PTR_ERR(authkey);
1535 goto error;
1536 }
1537
1538 ret = keyctl_change_reqkey_auth(authkey);
1539 if (ret == 0)
1540 ret = authkey->serial;
1541 key_put(authkey);
1542error:
1543 return ret;
1544}
1545
1546/*
1547 * Get a key's the LSM security label.
1548 *
1549 * The key must grant the caller View permission for this to work.
1550 *
1551 * If there's a buffer, then up to buflen bytes of data will be placed into it.
1552 *
1553 * If successful, the amount of information available will be returned,
1554 * irrespective of how much was copied (including the terminal NUL).
1555 */
1556long keyctl_get_security(key_serial_t keyid,
1557 char __user *buffer,
1558 size_t buflen)
1559{
1560 struct key *key, *instkey;
1561 key_ref_t key_ref;
1562 char *context;
1563 long ret;
1564
1565 key_ref = lookup_user_key(keyid, KEY_LOOKUP_PARTIAL, KEY_NEED_VIEW);
1566 if (IS_ERR(key_ref)) {
1567 if (PTR_ERR(key_ref) != -EACCES)
1568 return PTR_ERR(key_ref);
1569
1570 /* viewing a key under construction is also permitted if we
1571 * have the authorisation token handy */
1572 instkey = key_get_instantiation_authkey(keyid);
1573 if (IS_ERR(instkey))
1574 return PTR_ERR(instkey);
1575 key_put(instkey);
1576
1577 key_ref = lookup_user_key(keyid, KEY_LOOKUP_PARTIAL,
1578 KEY_AUTHTOKEN_OVERRIDE);
1579 if (IS_ERR(key_ref))
1580 return PTR_ERR(key_ref);
1581 }
1582
1583 key = key_ref_to_ptr(key_ref);
1584 ret = security_key_getsecurity(key, &context);
1585 if (ret == 0) {
1586 /* if no information was returned, give userspace an empty
1587 * string */
1588 ret = 1;
1589 if (buffer && buflen > 0 &&
1590 copy_to_user(buffer, "", 1) != 0)
1591 ret = -EFAULT;
1592 } else if (ret > 0) {
1593 /* return as much data as there's room for */
1594 if (buffer && buflen > 0) {
1595 if (buflen > ret)
1596 buflen = ret;
1597
1598 if (copy_to_user(buffer, context, buflen) != 0)
1599 ret = -EFAULT;
1600 }
1601
1602 kfree(context);
1603 }
1604
1605 key_ref_put(key_ref);
1606 return ret;
1607}
1608
1609/*
1610 * Attempt to install the calling process's session keyring on the process's
1611 * parent process.
1612 *
1613 * The keyring must exist and must grant the caller LINK permission, and the
1614 * parent process must be single-threaded and must have the same effective
1615 * ownership as this process and mustn't be SUID/SGID.
1616 *
1617 * The keyring will be emplaced on the parent when it next resumes userspace.
1618 *
1619 * If successful, 0 will be returned.
1620 */
1621long keyctl_session_to_parent(void)
1622{
1623 struct task_struct *me, *parent;
1624 const struct cred *mycred, *pcred;
1625 struct callback_head *newwork, *oldwork;
1626 key_ref_t keyring_r;
1627 struct cred *cred;
1628 int ret;
1629
1630 keyring_r = lookup_user_key(KEY_SPEC_SESSION_KEYRING, 0, KEY_NEED_LINK);
1631 if (IS_ERR(keyring_r))
1632 return PTR_ERR(keyring_r);
1633
1634 ret = -ENOMEM;
1635
1636 /* our parent is going to need a new cred struct, a new tgcred struct
1637 * and new security data, so we allocate them here to prevent ENOMEM in
1638 * our parent */
1639 cred = cred_alloc_blank();
1640 if (!cred)
1641 goto error_keyring;
1642 newwork = &cred->rcu;
1643
1644 cred->session_keyring = key_ref_to_ptr(keyring_r);
1645 keyring_r = NULL;
1646 init_task_work(newwork, key_change_session_keyring);
1647
1648 me = current;
1649 rcu_read_lock();
1650 write_lock_irq(&tasklist_lock);
1651
1652 ret = -EPERM;
1653 oldwork = NULL;
1654 parent = rcu_dereference_protected(me->real_parent,
1655 lockdep_is_held(&tasklist_lock));
1656
1657 /* the parent mustn't be init and mustn't be a kernel thread */
1658 if (parent->pid <= 1 || !parent->mm)
1659 goto unlock;
1660
1661 /* the parent must be single threaded */
1662 if (!thread_group_empty(parent))
1663 goto unlock;
1664
1665 /* the parent and the child must have different session keyrings or
1666 * there's no point */
1667 mycred = current_cred();
1668 pcred = __task_cred(parent);
1669 if (mycred == pcred ||
1670 mycred->session_keyring == pcred->session_keyring) {
1671 ret = 0;
1672 goto unlock;
1673 }
1674
1675 /* the parent must have the same effective ownership and mustn't be
1676 * SUID/SGID */
1677 if (!uid_eq(pcred->uid, mycred->euid) ||
1678 !uid_eq(pcred->euid, mycred->euid) ||
1679 !uid_eq(pcred->suid, mycred->euid) ||
1680 !gid_eq(pcred->gid, mycred->egid) ||
1681 !gid_eq(pcred->egid, mycred->egid) ||
1682 !gid_eq(pcred->sgid, mycred->egid))
1683 goto unlock;
1684
1685 /* the keyrings must have the same UID */
1686 if ((pcred->session_keyring &&
1687 !uid_eq(pcred->session_keyring->uid, mycred->euid)) ||
1688 !uid_eq(mycred->session_keyring->uid, mycred->euid))
1689 goto unlock;
1690
1691 /* cancel an already pending keyring replacement */
1692 oldwork = task_work_cancel(parent, key_change_session_keyring);
1693
1694 /* the replacement session keyring is applied just prior to userspace
1695 * restarting */
1696 ret = task_work_add(parent, newwork, TWA_RESUME);
1697 if (!ret)
1698 newwork = NULL;
1699unlock:
1700 write_unlock_irq(&tasklist_lock);
1701 rcu_read_unlock();
1702 if (oldwork)
1703 put_cred(container_of(oldwork, struct cred, rcu));
1704 if (newwork)
1705 put_cred(cred);
1706 return ret;
1707
1708error_keyring:
1709 key_ref_put(keyring_r);
1710 return ret;
1711}
1712
1713/*
1714 * Apply a restriction to a given keyring.
1715 *
1716 * The caller must have Setattr permission to change keyring restrictions.
1717 *
1718 * The requested type name may be a NULL pointer to reject all attempts
1719 * to link to the keyring. In this case, _restriction must also be NULL.
1720 * Otherwise, both _type and _restriction must be non-NULL.
1721 *
1722 * Returns 0 if successful.
1723 */
1724long keyctl_restrict_keyring(key_serial_t id, const char __user *_type,
1725 const char __user *_restriction)
1726{
1727 key_ref_t key_ref;
1728 char type[32];
1729 char *restriction = NULL;
1730 long ret;
1731
1732 key_ref = lookup_user_key(id, 0, KEY_NEED_SETATTR);
1733 if (IS_ERR(key_ref))
1734 return PTR_ERR(key_ref);
1735
1736 ret = -EINVAL;
1737 if (_type) {
1738 if (!_restriction)
1739 goto error;
1740
1741 ret = key_get_type_from_user(type, _type, sizeof(type));
1742 if (ret < 0)
1743 goto error;
1744
1745 restriction = strndup_user(_restriction, PAGE_SIZE);
1746 if (IS_ERR(restriction)) {
1747 ret = PTR_ERR(restriction);
1748 goto error;
1749 }
1750 } else {
1751 if (_restriction)
1752 goto error;
1753 }
1754
1755 ret = keyring_restrict(key_ref, _type ? type : NULL, restriction);
1756 kfree(restriction);
1757error:
1758 key_ref_put(key_ref);
1759 return ret;
1760}
1761
1762#ifdef CONFIG_KEY_NOTIFICATIONS
1763/*
1764 * Watch for changes to a key.
1765 *
1766 * The caller must have View permission to watch a key or keyring.
1767 */
1768long keyctl_watch_key(key_serial_t id, int watch_queue_fd, int watch_id)
1769{
1770 struct watch_queue *wqueue;
1771 struct watch_list *wlist = NULL;
1772 struct watch *watch = NULL;
1773 struct key *key;
1774 key_ref_t key_ref;
1775 long ret;
1776
1777 if (watch_id < -1 || watch_id > 0xff)
1778 return -EINVAL;
1779
1780 key_ref = lookup_user_key(id, KEY_LOOKUP_CREATE, KEY_NEED_VIEW);
1781 if (IS_ERR(key_ref))
1782 return PTR_ERR(key_ref);
1783 key = key_ref_to_ptr(key_ref);
1784
1785 wqueue = get_watch_queue(watch_queue_fd);
1786 if (IS_ERR(wqueue)) {
1787 ret = PTR_ERR(wqueue);
1788 goto err_key;
1789 }
1790
1791 if (watch_id >= 0) {
1792 ret = -ENOMEM;
1793 if (!key->watchers) {
1794 wlist = kzalloc(sizeof(*wlist), GFP_KERNEL);
1795 if (!wlist)
1796 goto err_wqueue;
1797 init_watch_list(wlist, NULL);
1798 }
1799
1800 watch = kzalloc(sizeof(*watch), GFP_KERNEL);
1801 if (!watch)
1802 goto err_wlist;
1803
1804 init_watch(watch, wqueue);
1805 watch->id = key->serial;
1806 watch->info_id = (u32)watch_id << WATCH_INFO_ID__SHIFT;
1807
1808 ret = security_watch_key(key);
1809 if (ret < 0)
1810 goto err_watch;
1811
1812 down_write(&key->sem);
1813 if (!key->watchers) {
1814 key->watchers = wlist;
1815 wlist = NULL;
1816 }
1817
1818 ret = add_watch_to_object(watch, key->watchers);
1819 up_write(&key->sem);
1820
1821 if (ret == 0)
1822 watch = NULL;
1823 } else {
1824 ret = -EBADSLT;
1825 if (key->watchers) {
1826 down_write(&key->sem);
1827 ret = remove_watch_from_object(key->watchers,
1828 wqueue, key_serial(key),
1829 false);
1830 up_write(&key->sem);
1831 }
1832 }
1833
1834err_watch:
1835 kfree(watch);
1836err_wlist:
1837 kfree(wlist);
1838err_wqueue:
1839 put_watch_queue(wqueue);
1840err_key:
1841 key_put(key);
1842 return ret;
1843}
1844#endif /* CONFIG_KEY_NOTIFICATIONS */
1845
1846/*
1847 * Get keyrings subsystem capabilities.
1848 */
1849long keyctl_capabilities(unsigned char __user *_buffer, size_t buflen)
1850{
1851 size_t size = buflen;
1852
1853 if (size > 0) {
1854 if (size > sizeof(keyrings_capabilities))
1855 size = sizeof(keyrings_capabilities);
1856 if (copy_to_user(_buffer, keyrings_capabilities, size) != 0)
1857 return -EFAULT;
1858 if (size < buflen &&
1859 clear_user(_buffer + size, buflen - size) != 0)
1860 return -EFAULT;
1861 }
1862
1863 return sizeof(keyrings_capabilities);
1864}
1865
1866/*
1867 * The key control system call
1868 */
1869SYSCALL_DEFINE5(keyctl, int, option, unsigned long, arg2, unsigned long, arg3,
1870 unsigned long, arg4, unsigned long, arg5)
1871{
1872 switch (option) {
1873 case KEYCTL_GET_KEYRING_ID:
1874 return keyctl_get_keyring_ID((key_serial_t) arg2,
1875 (int) arg3);
1876
1877 case KEYCTL_JOIN_SESSION_KEYRING:
1878 return keyctl_join_session_keyring((const char __user *) arg2);
1879
1880 case KEYCTL_UPDATE:
1881 return keyctl_update_key((key_serial_t) arg2,
1882 (const void __user *) arg3,
1883 (size_t) arg4);
1884
1885 case KEYCTL_REVOKE:
1886 return keyctl_revoke_key((key_serial_t) arg2);
1887
1888 case KEYCTL_DESCRIBE:
1889 return keyctl_describe_key((key_serial_t) arg2,
1890 (char __user *) arg3,
1891 (unsigned) arg4);
1892
1893 case KEYCTL_CLEAR:
1894 return keyctl_keyring_clear((key_serial_t) arg2);
1895
1896 case KEYCTL_LINK:
1897 return keyctl_keyring_link((key_serial_t) arg2,
1898 (key_serial_t) arg3);
1899
1900 case KEYCTL_UNLINK:
1901 return keyctl_keyring_unlink((key_serial_t) arg2,
1902 (key_serial_t) arg3);
1903
1904 case KEYCTL_SEARCH:
1905 return keyctl_keyring_search((key_serial_t) arg2,
1906 (const char __user *) arg3,
1907 (const char __user *) arg4,
1908 (key_serial_t) arg5);
1909
1910 case KEYCTL_READ:
1911 return keyctl_read_key((key_serial_t) arg2,
1912 (char __user *) arg3,
1913 (size_t) arg4);
1914
1915 case KEYCTL_CHOWN:
1916 return keyctl_chown_key((key_serial_t) arg2,
1917 (uid_t) arg3,
1918 (gid_t) arg4);
1919
1920 case KEYCTL_SETPERM:
1921 return keyctl_setperm_key((key_serial_t) arg2,
1922 (key_perm_t) arg3);
1923
1924 case KEYCTL_INSTANTIATE:
1925 return keyctl_instantiate_key((key_serial_t) arg2,
1926 (const void __user *) arg3,
1927 (size_t) arg4,
1928 (key_serial_t) arg5);
1929
1930 case KEYCTL_NEGATE:
1931 return keyctl_negate_key((key_serial_t) arg2,
1932 (unsigned) arg3,
1933 (key_serial_t) arg4);
1934
1935 case KEYCTL_SET_REQKEY_KEYRING:
1936 return keyctl_set_reqkey_keyring(arg2);
1937
1938 case KEYCTL_SET_TIMEOUT:
1939 return keyctl_set_timeout((key_serial_t) arg2,
1940 (unsigned) arg3);
1941
1942 case KEYCTL_ASSUME_AUTHORITY:
1943 return keyctl_assume_authority((key_serial_t) arg2);
1944
1945 case KEYCTL_GET_SECURITY:
1946 return keyctl_get_security((key_serial_t) arg2,
1947 (char __user *) arg3,
1948 (size_t) arg4);
1949
1950 case KEYCTL_SESSION_TO_PARENT:
1951 return keyctl_session_to_parent();
1952
1953 case KEYCTL_REJECT:
1954 return keyctl_reject_key((key_serial_t) arg2,
1955 (unsigned) arg3,
1956 (unsigned) arg4,
1957 (key_serial_t) arg5);
1958
1959 case KEYCTL_INSTANTIATE_IOV:
1960 return keyctl_instantiate_key_iov(
1961 (key_serial_t) arg2,
1962 (const struct iovec __user *) arg3,
1963 (unsigned) arg4,
1964 (key_serial_t) arg5);
1965
1966 case KEYCTL_INVALIDATE:
1967 return keyctl_invalidate_key((key_serial_t) arg2);
1968
1969 case KEYCTL_GET_PERSISTENT:
1970 return keyctl_get_persistent((uid_t)arg2, (key_serial_t)arg3);
1971
1972 case KEYCTL_DH_COMPUTE:
1973 return keyctl_dh_compute((struct keyctl_dh_params __user *) arg2,
1974 (char __user *) arg3, (size_t) arg4,
1975 (struct keyctl_kdf_params __user *) arg5);
1976
1977 case KEYCTL_RESTRICT_KEYRING:
1978 return keyctl_restrict_keyring((key_serial_t) arg2,
1979 (const char __user *) arg3,
1980 (const char __user *) arg4);
1981
1982 case KEYCTL_PKEY_QUERY:
1983 if (arg3 != 0)
1984 return -EINVAL;
1985 return keyctl_pkey_query((key_serial_t)arg2,
1986 (const char __user *)arg4,
1987 (struct keyctl_pkey_query __user *)arg5);
1988
1989 case KEYCTL_PKEY_ENCRYPT:
1990 case KEYCTL_PKEY_DECRYPT:
1991 case KEYCTL_PKEY_SIGN:
1992 return keyctl_pkey_e_d_s(
1993 option,
1994 (const struct keyctl_pkey_params __user *)arg2,
1995 (const char __user *)arg3,
1996 (const void __user *)arg4,
1997 (void __user *)arg5);
1998
1999 case KEYCTL_PKEY_VERIFY:
2000 return keyctl_pkey_verify(
2001 (const struct keyctl_pkey_params __user *)arg2,
2002 (const char __user *)arg3,
2003 (const void __user *)arg4,
2004 (const void __user *)arg5);
2005
2006 case KEYCTL_MOVE:
2007 return keyctl_keyring_move((key_serial_t)arg2,
2008 (key_serial_t)arg3,
2009 (key_serial_t)arg4,
2010 (unsigned int)arg5);
2011
2012 case KEYCTL_CAPABILITIES:
2013 return keyctl_capabilities((unsigned char __user *)arg2, (size_t)arg3);
2014
2015 case KEYCTL_WATCH_KEY:
2016 return keyctl_watch_key((key_serial_t)arg2, (int)arg3, (int)arg4);
2017
2018 default:
2019 return -EOPNOTSUPP;
2020 }
2021}