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