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