1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /* Userspace key control operations
3 *
4 * Copyright (C) 2004-5 Red Hat, Inc. All Rights Reserved.
5 * Written by David Howells (dhowells@redhat.com)
6 */
7
8 #include <linux/init.h>
9 #include <linux/sched.h>
10 #include <linux/sched/task.h>
11 #include <linux/slab.h>
12 #include <linux/syscalls.h>
13 #include <linux/key.h>
14 #include <linux/keyctl.h>
15 #include <linux/fs.h>
16 #include <linux/capability.h>
17 #include <linux/cred.h>
18 #include <linux/string.h>
19 #include <linux/err.h>
20 #include <linux/vmalloc.h>
21 #include <linux/security.h>
22 #include <linux/uio.h>
23 #include <linux/uaccess.h>
24 #include <keys/request_key_auth-type.h>
25 #include "internal.h"
26
27 #define KEY_MAX_DESC_SIZE 4096
28
29 static const unsigned char keyrings_capabilities[2] = {
30 [0] = (KEYCTL_CAPS0_CAPABILITIES |
31 (IS_ENABLED(CONFIG_PERSISTENT_KEYRINGS) ? KEYCTL_CAPS0_PERSISTENT_KEYRINGS : 0) |
32 (IS_ENABLED(CONFIG_KEY_DH_OPERATIONS) ? KEYCTL_CAPS0_DIFFIE_HELLMAN : 0) |
33 (IS_ENABLED(CONFIG_ASYMMETRIC_KEY_TYPE) ? KEYCTL_CAPS0_PUBLIC_KEY : 0) |
34 (IS_ENABLED(CONFIG_BIG_KEYS) ? KEYCTL_CAPS0_BIG_KEY : 0) |
35 KEYCTL_CAPS0_INVALIDATE |
36 KEYCTL_CAPS0_RESTRICT_KEYRING |
37 KEYCTL_CAPS0_MOVE
38 ),
39 [1] = (KEYCTL_CAPS1_NS_KEYRING_NAME |
40 KEYCTL_CAPS1_NS_KEY_TAG |
41 (IS_ENABLED(CONFIG_KEY_NOTIFICATIONS) ? KEYCTL_CAPS1_NOTIFICATIONS : 0)
42 ),
43 };
44
45 static int key_get_type_from_user(char *type,
46 const char __user *_type,
47 unsigned len)
48 {
49 int ret;
50
51 ret = strncpy_from_user(type, _type, len);
52 if (ret < 0)
53 return ret;
54 if (ret == 0 || ret >= len)
55 return -EINVAL;
56 if (type[0] == '.')
57 return -EPERM;
58 type[len - 1] = '\0';
59 return 0;
60 }
61
62 /*
63 * Extract the description of a new key from userspace and either add it as a
64 * new key to the specified keyring or update a matching key in that keyring.
65 *
66 * If the description is NULL or an empty string, the key type is asked to
67 * generate one from the payload.
68 *
69 * The keyring must be writable so that we can attach the key to it.
70 *
71 * If successful, the new key's serial number is returned, otherwise an error
72 * code is returned.
73 */
74 SYSCALL_DEFINE5(add_key, const char __user *, _type,
75 const char __user *, _description,
76 const void __user *, _payload,
77 size_t, plen,
78 key_serial_t, ringid)
79 {
80 key_ref_t keyring_ref, key_ref;
81 char type[32], *description;
82 void *payload;
83 long ret;
84
85 ret = -EINVAL;
86 if (plen > 1024 * 1024 - 1)
87 goto error;
88
89 /* draw all the data into kernel space */
90 ret = key_get_type_from_user(type, _type, sizeof(type));
91 if (ret < 0)
92 goto error;
93
94 description = NULL;
95 if (_description) {
96 description = strndup_user(_description, KEY_MAX_DESC_SIZE);
97 if (IS_ERR(description)) {
98 ret = PTR_ERR(description);
99 goto error;
100 }
101 if (!*description) {
102 kfree(description);
103 description = NULL;
104 } else if ((description[0] == '.') &&
105 (strncmp(type, "keyring", 7) == 0)) {
106 ret = -EPERM;
107 goto error2;
108 }
109 }
110
111 /* pull the payload in if one was supplied */
112 payload = NULL;
113
114 if (plen) {
115 ret = -ENOMEM;
116 payload = kvmalloc(plen, GFP_KERNEL);
117 if (!payload)
118 goto error2;
119
120 ret = -EFAULT;
121 if (copy_from_user(payload, _payload, plen) != 0)
122 goto error3;
123 }
124
125 /* find the target keyring (which must be writable) */
126 keyring_ref = lookup_user_key(ringid, KEY_LOOKUP_CREATE, KEY_NEED_WRITE);
127 if (IS_ERR(keyring_ref)) {
128 ret = PTR_ERR(keyring_ref);
129 goto error3;
130 }
131
132 /* create or update the requested key and add it to the target
133 * keyring */
134 key_ref = key_create_or_update(keyring_ref, type, description,
135 payload, plen, KEY_PERM_UNDEF,
136 KEY_ALLOC_IN_QUOTA);
137 if (!IS_ERR(key_ref)) {
138 ret = key_ref_to_ptr(key_ref)->serial;
139 key_ref_put(key_ref);
140 }
141 else {
142 ret = PTR_ERR(key_ref);
143 }
144
145 key_ref_put(keyring_ref);
146 error3:
147 kvfree_sensitive(payload, plen);
148 error2:
149 kfree(description);
150 error:
151 return ret;
152 }
153
154 /*
155 * Search the process keyrings and keyring trees linked from those for a
156 * matching key. Keyrings must have appropriate Search permission to be
157 * searched.
158 *
159 * If a key is found, it will be attached to the destination keyring if there's
160 * one specified and the serial number of the key will be returned.
161 *
162 * If no key is found, /sbin/request-key will be invoked if _callout_info is
163 * non-NULL in an attempt to create a key. The _callout_info string will be
164 * passed to /sbin/request-key to aid with completing the request. If the
165 * _callout_info string is "" then it will be changed to "-".
166 */
167 SYSCALL_DEFINE4(request_key, const char __user *, _type,
168 const char __user *, _description,
169 const char __user *, _callout_info,
170 key_serial_t, destringid)
171 {
172 struct key_type *ktype;
173 struct key *key;
174 key_ref_t dest_ref;
175 size_t callout_len;
176 char type[32], *description, *callout_info;
177 long ret;
178
179 /* pull the type into kernel space */
180 ret = key_get_type_from_user(type, _type, sizeof(type));
181 if (ret < 0)
182 goto error;
183
184 /* pull the description into kernel space */
185 description = strndup_user(_description, KEY_MAX_DESC_SIZE);
186 if (IS_ERR(description)) {
187 ret = PTR_ERR(description);
188 goto error;
189 }
190
191 /* pull the callout info into kernel space */
192 callout_info = NULL;
193 callout_len = 0;
194 if (_callout_info) {
195 callout_info = strndup_user(_callout_info, PAGE_SIZE);
196 if (IS_ERR(callout_info)) {
197 ret = PTR_ERR(callout_info);
198 goto error2;
199 }
200 callout_len = strlen(callout_info);
201 }
202
203 /* get the destination keyring if specified */
204 dest_ref = NULL;
205 if (destringid) {
206 dest_ref = lookup_user_key(destringid, KEY_LOOKUP_CREATE,
207 KEY_NEED_WRITE);
208 if (IS_ERR(dest_ref)) {
209 ret = PTR_ERR(dest_ref);
210 goto error3;
211 }
212 }
213
214 /* find the key type */
215 ktype = key_type_lookup(type);
216 if (IS_ERR(ktype)) {
217 ret = PTR_ERR(ktype);
218 goto error4;
219 }
220
221 /* do the search */
222 key = request_key_and_link(ktype, description, NULL, callout_info,
223 callout_len, NULL, key_ref_to_ptr(dest_ref),
224 KEY_ALLOC_IN_QUOTA);
225 if (IS_ERR(key)) {
226 ret = PTR_ERR(key);
227 goto error5;
228 }
229
230 /* wait for the key to finish being constructed */
231 ret = wait_for_key_construction(key, 1);
232 if (ret < 0)
233 goto error6;
234
235 ret = key->serial;
236
237 error6:
238 key_put(key);
239 error5:
240 key_type_put(ktype);
241 error4:
242 key_ref_put(dest_ref);
243 error3:
244 kfree(callout_info);
245 error2:
246 kfree(description);
247 error:
248 return ret;
249 }
250
251 /*
252 * Get the ID of the specified process keyring.
253 *
254 * The requested keyring must have search permission to be found.
255 *
256 * If successful, the ID of the requested keyring will be returned.
257 */
258 long keyctl_get_keyring_ID(key_serial_t id, int create)
259 {
260 key_ref_t key_ref;
261 unsigned long lflags;
262 long ret;
263
264 lflags = create ? KEY_LOOKUP_CREATE : 0;
265 key_ref = lookup_user_key(id, lflags, KEY_NEED_SEARCH);
266 if (IS_ERR(key_ref)) {
267 ret = PTR_ERR(key_ref);
268 goto error;
269 }
270
271 ret = key_ref_to_ptr(key_ref)->serial;
272 key_ref_put(key_ref);
273 error:
274 return ret;
275 }
276
277 /*
278 * Join a (named) session keyring.
279 *
280 * Create and join an anonymous session keyring or join a named session
281 * keyring, creating it if necessary. A named session keyring must have Search
282 * permission for it to be joined. Session keyrings without this permit will
283 * be skipped over. It is not permitted for userspace to create or join
284 * keyrings whose name begin with a dot.
285 *
286 * If successful, the ID of the joined session keyring will be returned.
287 */
288 long keyctl_join_session_keyring(const char __user *_name)
289 {
290 char *name;
291 long ret;
292
293 /* fetch the name from userspace */
294 name = NULL;
295 if (_name) {
296 name = strndup_user(_name, KEY_MAX_DESC_SIZE);
297 if (IS_ERR(name)) {
298 ret = PTR_ERR(name);
299 goto error;
300 }
301
302 ret = -EPERM;
303 if (name[0] == '.')
304 goto error_name;
305 }
306
307 /* join the session */
308 ret = join_session_keyring(name);
309 error_name:
310 kfree(name);
311 error:
312 return ret;
313 }
314
315 /*
316 * Update a key's data payload from the given data.
317 *
318 * The key must grant the caller Write permission and the key type must support
319 * updating for this to work. A negative key can be positively instantiated
320 * with this call.
321 *
322 * If successful, 0 will be returned. If the key type does not support
323 * updating, then -EOPNOTSUPP will be returned.
324 */
325 long keyctl_update_key(key_serial_t id,
326 const void __user *_payload,
327 size_t plen)
328 {
329 key_ref_t key_ref;
330 void *payload;
331 long ret;
332
333 ret = -EINVAL;
334 if (plen > PAGE_SIZE)
335 goto error;
336
337 /* pull the payload in if one was supplied */
338 payload = NULL;
339 if (plen) {
340 ret = -ENOMEM;
341 payload = kvmalloc(plen, GFP_KERNEL);
342 if (!payload)
343 goto error;
344
345 ret = -EFAULT;
346 if (copy_from_user(payload, _payload, plen) != 0)
347 goto error2;
348 }
349
350 /* find the target key (which must be writable) */
351 key_ref = lookup_user_key(id, 0, KEY_NEED_WRITE);
352 if (IS_ERR(key_ref)) {
353 ret = PTR_ERR(key_ref);
354 goto error2;
355 }
356
357 /* update the key */
358 ret = key_update(key_ref, payload, plen);
359
360 key_ref_put(key_ref);
361 error2:
362 kvfree_sensitive(payload, plen);
363 error:
364 return ret;
365 }
366
367 /*
368 * Revoke a key.
369 *
370 * The key must be grant the caller Write or Setattr permission for this to
371 * work. The key type should give up its quota claim when revoked. The key
372 * and any links to the key will be automatically garbage collected after a
373 * certain amount of time (/proc/sys/kernel/keys/gc_delay).
374 *
375 * Keys with KEY_FLAG_KEEP set should not be revoked.
376 *
377 * If successful, 0 is returned.
378 */
379 long keyctl_revoke_key(key_serial_t id)
380 {
381 key_ref_t key_ref;
382 struct key *key;
383 long ret;
384
385 key_ref = lookup_user_key(id, 0, KEY_NEED_WRITE);
386 if (IS_ERR(key_ref)) {
387 ret = PTR_ERR(key_ref);
388 if (ret != -EACCES)
389 goto error;
390 key_ref = lookup_user_key(id, 0, KEY_NEED_SETATTR);
391 if (IS_ERR(key_ref)) {
392 ret = PTR_ERR(key_ref);
393 goto error;
394 }
395 }
396
397 key = key_ref_to_ptr(key_ref);
398 ret = 0;
399 if (test_bit(KEY_FLAG_KEEP, &key->flags))
400 ret = -EPERM;
401 else
402 key_revoke(key);
403
404 key_ref_put(key_ref);
405 error:
406 return ret;
407 }
408
409 /*
410 * Invalidate a key.
411 *
412 * The key must be grant the caller Invalidate permission for this to work.
413 * The key and any links to the key will be automatically garbage collected
414 * immediately.
415 *
416 * Keys with KEY_FLAG_KEEP set should not be invalidated.
417 *
418 * If successful, 0 is returned.
419 */
420 long keyctl_invalidate_key(key_serial_t id)
421 {
422 key_ref_t key_ref;
423 struct key *key;
424 long ret;
425
426 kenter("%d", id);
427
428 key_ref = lookup_user_key(id, 0, KEY_NEED_SEARCH);
429 if (IS_ERR(key_ref)) {
430 ret = PTR_ERR(key_ref);
431
432 /* Root is permitted to invalidate certain special keys */
433 if (capable(CAP_SYS_ADMIN)) {
434 key_ref = lookup_user_key(id, 0, KEY_SYSADMIN_OVERRIDE);
435 if (IS_ERR(key_ref))
436 goto error;
437 if (test_bit(KEY_FLAG_ROOT_CAN_INVAL,
438 &key_ref_to_ptr(key_ref)->flags))
439 goto invalidate;
440 goto error_put;
441 }
442
443 goto error;
444 }
445
446 invalidate:
447 key = key_ref_to_ptr(key_ref);
448 ret = 0;
449 if (test_bit(KEY_FLAG_KEEP, &key->flags))
450 ret = -EPERM;
451 else
452 key_invalidate(key);
453 error_put:
454 key_ref_put(key_ref);
455 error:
456 kleave(" = %ld", ret);
457 return ret;
458 }
459
460 /*
461 * Clear the specified keyring, creating an empty process keyring if one of the
462 * special keyring IDs is used.
463 *
464 * The keyring must grant the caller Write permission and not have
465 * KEY_FLAG_KEEP set for this to work. If successful, 0 will be returned.
466 */
467 long keyctl_keyring_clear(key_serial_t ringid)
468 {
469 key_ref_t keyring_ref;
470 struct key *keyring;
471 long ret;
472
473 keyring_ref = lookup_user_key(ringid, KEY_LOOKUP_CREATE, KEY_NEED_WRITE);
474 if (IS_ERR(keyring_ref)) {
475 ret = PTR_ERR(keyring_ref);
476
477 /* Root is permitted to invalidate certain special keyrings */
478 if (capable(CAP_SYS_ADMIN)) {
479 keyring_ref = lookup_user_key(ringid, 0,
480 KEY_SYSADMIN_OVERRIDE);
481 if (IS_ERR(keyring_ref))
482 goto error;
483 if (test_bit(KEY_FLAG_ROOT_CAN_CLEAR,
484 &key_ref_to_ptr(keyring_ref)->flags))
485 goto clear;
486 goto error_put;
487 }
488
489 goto error;
490 }
491
492 clear:
493 keyring = key_ref_to_ptr(keyring_ref);
494 if (test_bit(KEY_FLAG_KEEP, &keyring->flags))
495 ret = -EPERM;
496 else
497 ret = keyring_clear(keyring);
498 error_put:
499 key_ref_put(keyring_ref);
500 error:
501 return ret;
502 }
503
504 /*
505 * Create a link from a keyring to a key if there's no matching key in the
506 * keyring, otherwise replace the link to the matching key with a link to the
507 * new key.
508 *
509 * The key must grant the caller Link permission and the keyring must grant
510 * the caller Write permission. Furthermore, if an additional link is created,
511 * the keyring's quota will be extended.
512 *
513 * If successful, 0 will be returned.
514 */
515 long keyctl_keyring_link(key_serial_t id, key_serial_t ringid)
516 {
517 key_ref_t keyring_ref, key_ref;
518 long ret;
519
520 keyring_ref = lookup_user_key(ringid, KEY_LOOKUP_CREATE, KEY_NEED_WRITE);
521 if (IS_ERR(keyring_ref)) {
522 ret = PTR_ERR(keyring_ref);
523 goto error;
524 }
525
526 key_ref = lookup_user_key(id, KEY_LOOKUP_CREATE, KEY_NEED_LINK);
527 if (IS_ERR(key_ref)) {
528 ret = PTR_ERR(key_ref);
529 goto error2;
530 }
531
532 ret = key_link(key_ref_to_ptr(keyring_ref), key_ref_to_ptr(key_ref));
533
534 key_ref_put(key_ref);
535 error2:
536 key_ref_put(keyring_ref);
537 error:
538 return ret;
539 }
540
541 /*
542 * Unlink a key from a keyring.
543 *
544 * The keyring must grant the caller Write permission for this to work; the key
545 * itself need not grant the caller anything. If the last link to a key is
546 * removed then that key will be scheduled for destruction.
547 *
548 * Keys or keyrings with KEY_FLAG_KEEP set should not be unlinked.
549 *
550 * If successful, 0 will be returned.
551 */
552 long keyctl_keyring_unlink(key_serial_t id, key_serial_t ringid)
553 {
554 key_ref_t keyring_ref, key_ref;
555 struct key *keyring, *key;
556 long ret;
557
558 keyring_ref = lookup_user_key(ringid, 0, KEY_NEED_WRITE);
559 if (IS_ERR(keyring_ref)) {
560 ret = PTR_ERR(keyring_ref);
561 goto error;
562 }
563
564 key_ref = lookup_user_key(id, KEY_LOOKUP_PARTIAL, KEY_NEED_UNLINK);
565 if (IS_ERR(key_ref)) {
566 ret = PTR_ERR(key_ref);
567 goto error2;
568 }
569
570 keyring = key_ref_to_ptr(keyring_ref);
571 key = key_ref_to_ptr(key_ref);
572 if (test_bit(KEY_FLAG_KEEP, &keyring->flags) &&
573 test_bit(KEY_FLAG_KEEP, &key->flags))
574 ret = -EPERM;
575 else
576 ret = key_unlink(keyring, key);
577
578 key_ref_put(key_ref);
579 error2:
580 key_ref_put(keyring_ref);
581 error:
582 return ret;
583 }
584
585 /*
586 * Move a link to a key from one keyring to another, displacing any matching
587 * key from the destination keyring.
588 *
589 * The key must grant the caller Link permission and both keyrings must grant
590 * the caller Write permission. There must also be a link in the from keyring
591 * to the key. If both keyrings are the same, nothing is done.
592 *
593 * If successful, 0 will be returned.
594 */
595 long keyctl_keyring_move(key_serial_t id, key_serial_t from_ringid,
596 key_serial_t to_ringid, unsigned int flags)
597 {
598 key_ref_t key_ref, from_ref, to_ref;
599 long ret;
600
601 if (flags & ~KEYCTL_MOVE_EXCL)
602 return -EINVAL;
603
604 key_ref = lookup_user_key(id, KEY_LOOKUP_CREATE, KEY_NEED_LINK);
605 if (IS_ERR(key_ref))
606 return PTR_ERR(key_ref);
607
608 from_ref = lookup_user_key(from_ringid, 0, KEY_NEED_WRITE);
609 if (IS_ERR(from_ref)) {
610 ret = PTR_ERR(from_ref);
611 goto error2;
612 }
613
614 to_ref = lookup_user_key(to_ringid, KEY_LOOKUP_CREATE, KEY_NEED_WRITE);
615 if (IS_ERR(to_ref)) {
616 ret = PTR_ERR(to_ref);
617 goto error3;
618 }
619
620 ret = key_move(key_ref_to_ptr(key_ref), key_ref_to_ptr(from_ref),
621 key_ref_to_ptr(to_ref), flags);
622
623 key_ref_put(to_ref);
624 error3:
625 key_ref_put(from_ref);
626 error2:
627 key_ref_put(key_ref);
628 return ret;
629 }
630
631 /*
632 * Return a description of a key to userspace.
633 *
634 * The key must grant the caller View permission for this to work.
635 *
636 * If there's a buffer, we place up to buflen bytes of data into it formatted
637 * in the following way:
638 *
639 * type;uid;gid;perm;description<NUL>
640 *
641 * If successful, we return the amount of description available, irrespective
642 * of how much we may have copied into the buffer.
643 */
644 long keyctl_describe_key(key_serial_t keyid,
645 char __user *buffer,
646 size_t buflen)
647 {
648 struct key *key, *instkey;
649 key_ref_t key_ref;
650 char *infobuf;
651 long ret;
652 int desclen, infolen;
653
654 key_ref = lookup_user_key(keyid, KEY_LOOKUP_PARTIAL, KEY_NEED_VIEW);
655 if (IS_ERR(key_ref)) {
656 /* viewing a key under construction is permitted if we have the
657 * authorisation token handy */
658 if (PTR_ERR(key_ref) == -EACCES) {
659 instkey = key_get_instantiation_authkey(keyid);
660 if (!IS_ERR(instkey)) {
661 key_put(instkey);
662 key_ref = lookup_user_key(keyid,
663 KEY_LOOKUP_PARTIAL,
664 KEY_AUTHTOKEN_OVERRIDE);
665 if (!IS_ERR(key_ref))
666 goto okay;
667 }
668 }
669
670 ret = PTR_ERR(key_ref);
671 goto error;
672 }
673
674 okay:
675 key = key_ref_to_ptr(key_ref);
676 desclen = strlen(key->description);
677
678 /* calculate how much information we're going to return */
679 ret = -ENOMEM;
680 infobuf = kasprintf(GFP_KERNEL,
681 "%s;%d;%d;%08x;",
682 key->type->name,
683 from_kuid_munged(current_user_ns(), key->uid),
684 from_kgid_munged(current_user_ns(), key->gid),
685 key->perm);
686 if (!infobuf)
687 goto error2;
688 infolen = strlen(infobuf);
689 ret = infolen + desclen + 1;
690
691 /* consider returning the data */
692 if (buffer && buflen >= ret) {
693 if (copy_to_user(buffer, infobuf, infolen) != 0 ||
694 copy_to_user(buffer + infolen, key->description,
695 desclen + 1) != 0)
696 ret = -EFAULT;
697 }
698
699 kfree(infobuf);
700 error2:
701 key_ref_put(key_ref);
702 error:
703 return ret;
704 }
705
706 /*
707 * Search the specified keyring and any keyrings it links to for a matching
708 * key. Only keyrings that grant the caller Search permission will be searched
709 * (this includes the starting keyring). Only keys with Search permission can
710 * be found.
711 *
712 * If successful, the found key will be linked to the destination keyring if
713 * supplied and the key has Link permission, and the found key ID will be
714 * returned.
715 */
716 long keyctl_keyring_search(key_serial_t ringid,
717 const char __user *_type,
718 const char __user *_description,
719 key_serial_t destringid)
720 {
721 struct key_type *ktype;
722 key_ref_t keyring_ref, key_ref, dest_ref;
723 char type[32], *description;
724 long ret;
725
726 /* pull the type and description into kernel space */
727 ret = key_get_type_from_user(type, _type, sizeof(type));
728 if (ret < 0)
729 goto error;
730
731 description = strndup_user(_description, KEY_MAX_DESC_SIZE);
732 if (IS_ERR(description)) {
733 ret = PTR_ERR(description);
734 goto error;
735 }
736
737 /* get the keyring at which to begin the search */
738 keyring_ref = lookup_user_key(ringid, 0, KEY_NEED_SEARCH);
739 if (IS_ERR(keyring_ref)) {
740 ret = PTR_ERR(keyring_ref);
741 goto error2;
742 }
743
744 /* get the destination keyring if specified */
745 dest_ref = NULL;
746 if (destringid) {
747 dest_ref = lookup_user_key(destringid, KEY_LOOKUP_CREATE,
748 KEY_NEED_WRITE);
749 if (IS_ERR(dest_ref)) {
750 ret = PTR_ERR(dest_ref);
751 goto error3;
752 }
753 }
754
755 /* find the key type */
756 ktype = key_type_lookup(type);
757 if (IS_ERR(ktype)) {
758 ret = PTR_ERR(ktype);
759 goto error4;
760 }
761
762 /* do the search */
763 key_ref = keyring_search(keyring_ref, ktype, description, true);
764 if (IS_ERR(key_ref)) {
765 ret = PTR_ERR(key_ref);
766
767 /* treat lack or presence of a negative key the same */
768 if (ret == -EAGAIN)
769 ret = -ENOKEY;
770 goto error5;
771 }
772
773 /* link the resulting key to the destination keyring if we can */
774 if (dest_ref) {
775 ret = key_permission(key_ref, KEY_NEED_LINK);
776 if (ret < 0)
777 goto error6;
778
779 ret = key_link(key_ref_to_ptr(dest_ref), key_ref_to_ptr(key_ref));
780 if (ret < 0)
781 goto error6;
782 }
783
784 ret = key_ref_to_ptr(key_ref)->serial;
785
786 error6:
787 key_ref_put(key_ref);
788 error5:
789 key_type_put(ktype);
790 error4:
791 key_ref_put(dest_ref);
792 error3:
793 key_ref_put(keyring_ref);
794 error2:
795 kfree(description);
796 error:
797 return ret;
798 }
799
800 /*
801 * Call the read method
802 */
803 static long __keyctl_read_key(struct key *key, char *buffer, size_t buflen)
804 {
805 long ret;
806
807 down_read(&key->sem);
808 ret = key_validate(key);
809 if (ret == 0)
810 ret = key->type->read(key, buffer, buflen);
811 up_read(&key->sem);
812 return ret;
813 }
814
815 /*
816 * Read a key's payload.
817 *
818 * The key must either grant the caller Read permission, or it must grant the
819 * caller Search permission when searched for from the process keyrings.
820 *
821 * If successful, we place up to buflen bytes of data into the buffer, if one
822 * is provided, and return the amount of data that is available in the key,
823 * irrespective of how much we copied into the buffer.
824 */
825 long keyctl_read_key(key_serial_t keyid, char __user *buffer, size_t buflen)
826 {
827 struct key *key;
828 key_ref_t key_ref;
829 long ret;
830 char *key_data = NULL;
831 size_t key_data_len;
832
833 /* find the key first */
834 key_ref = lookup_user_key(keyid, 0, KEY_DEFER_PERM_CHECK);
835 if (IS_ERR(key_ref)) {
836 ret = -ENOKEY;
837 goto out;
838 }
839
840 key = key_ref_to_ptr(key_ref);
841
842 ret = key_read_state(key);
843 if (ret < 0)
844 goto key_put_out; /* Negatively instantiated */
845
846 /* see if we can read it directly */
847 ret = key_permission(key_ref, KEY_NEED_READ);
848 if (ret == 0)
849 goto can_read_key;
850 if (ret != -EACCES)
851 goto key_put_out;
852
853 /* we can't; see if it's searchable from this process's keyrings
854 * - we automatically take account of the fact that it may be
855 * dangling off an instantiation key
856 */
857 if (!is_key_possessed(key_ref)) {
858 ret = -EACCES;
859 goto key_put_out;
860 }
861
862 /* the key is probably readable - now try to read it */
863 can_read_key:
864 if (!key->type->read) {
865 ret = -EOPNOTSUPP;
866 goto key_put_out;
867 }
868
869 if (!buffer || !buflen) {
870 /* Get the key length from the read method */
871 ret = __keyctl_read_key(key, NULL, 0);
872 goto key_put_out;
873 }
874
875 /*
876 * Read the data with the semaphore held (since we might sleep)
877 * to protect against the key being updated or revoked.
878 *
879 * Allocating a temporary buffer to hold the keys before
880 * transferring them to user buffer to avoid potential
881 * deadlock involving page fault and mmap_lock.
882 *
883 * key_data_len = (buflen <= PAGE_SIZE)
884 * ? buflen : actual length of key data
885 *
886 * This prevents allocating arbitrary large buffer which can
887 * be much larger than the actual key length. In the latter case,
888 * at least 2 passes of this loop is required.
889 */
890 key_data_len = (buflen <= PAGE_SIZE) ? buflen : 0;
891 for (;;) {
892 if (key_data_len) {
893 key_data = kvmalloc(key_data_len, GFP_KERNEL);
894 if (!key_data) {
895 ret = -ENOMEM;
896 goto key_put_out;
897 }
898 }
899
900 ret = __keyctl_read_key(key, key_data, key_data_len);
901
902 /*
903 * Read methods will just return the required length without
904 * any copying if the provided length isn't large enough.
905 */
906 if (ret <= 0 || ret > buflen)
907 break;
908
909 /*
910 * The key may change (unlikely) in between 2 consecutive
911 * __keyctl_read_key() calls. In this case, we reallocate
912 * a larger buffer and redo the key read when
913 * key_data_len < ret <= buflen.
914 */
915 if (ret > key_data_len) {
916 if (unlikely(key_data))
917 kvfree_sensitive(key_data, key_data_len);
918 key_data_len = ret;
919 continue; /* Allocate buffer */
920 }
921
922 if (copy_to_user(buffer, key_data, ret))
923 ret = -EFAULT;
924 break;
925 }
926 kvfree_sensitive(key_data, key_data_len);
927
928 key_put_out:
929 key_put(key);
930 out:
931 return ret;
932 }
933
934 /*
935 * Change the ownership of a key
936 *
937 * The key must grant the caller Setattr permission for this to work, though
938 * the key need not be fully instantiated yet. For the UID to be changed, or
939 * for the GID to be changed to a group the caller is not a member of, the
940 * caller must have sysadmin capability. If either uid or gid is -1 then that
941 * attribute is not changed.
942 *
943 * If the UID is to be changed, the new user must have sufficient quota to
944 * accept the key. The quota deduction will be removed from the old user to
945 * the new user should the attribute be changed.
946 *
947 * If successful, 0 will be returned.
948 */
949 long keyctl_chown_key(key_serial_t id, uid_t user, gid_t group)
950 {
951 struct key_user *newowner, *zapowner = NULL;
952 struct key *key;
953 key_ref_t key_ref;
954 long ret;
955 kuid_t uid;
956 kgid_t gid;
957 unsigned long flags;
958
959 uid = make_kuid(current_user_ns(), user);
960 gid = make_kgid(current_user_ns(), group);
961 ret = -EINVAL;
962 if ((user != (uid_t) -1) && !uid_valid(uid))
963 goto error;
964 if ((group != (gid_t) -1) && !gid_valid(gid))
965 goto error;
966
967 ret = 0;
968 if (user == (uid_t) -1 && group == (gid_t) -1)
969 goto error;
970
971 key_ref = lookup_user_key(id, KEY_LOOKUP_CREATE | KEY_LOOKUP_PARTIAL,
972 KEY_NEED_SETATTR);
973 if (IS_ERR(key_ref)) {
974 ret = PTR_ERR(key_ref);
975 goto error;
976 }
977
978 key = key_ref_to_ptr(key_ref);
979
980 /* make the changes with the locks held to prevent chown/chown races */
981 ret = -EACCES;
982 down_write(&key->sem);
983
984 {
985 bool is_privileged_op = false;
986
987 /* only the sysadmin can chown a key to some other UID */
988 if (user != (uid_t) -1 && !uid_eq(key->uid, uid))
989 is_privileged_op = true;
990
991 /* only the sysadmin can set the key's GID to a group other
992 * than one of those that the current process subscribes to */
993 if (group != (gid_t) -1 && !gid_eq(gid, key->gid) && !in_group_p(gid))
994 is_privileged_op = true;
995
996 if (is_privileged_op && !capable(CAP_SYS_ADMIN))
997 goto error_put;
998 }
999
1000 /* change the UID */
1001 if (user != (uid_t) -1 && !uid_eq(uid, key->uid)) {
1002 ret = -ENOMEM;
1003 newowner = key_user_lookup(uid);
1004 if (!newowner)
1005 goto error_put;
1006
1007 /* transfer the quota burden to the new user */
1008 if (test_bit(KEY_FLAG_IN_QUOTA, &key->flags)) {
1009 unsigned maxkeys = uid_eq(uid, GLOBAL_ROOT_UID) ?
1010 key_quota_root_maxkeys : key_quota_maxkeys;
1011 unsigned maxbytes = uid_eq(uid, GLOBAL_ROOT_UID) ?
1012 key_quota_root_maxbytes : key_quota_maxbytes;
1013
1014 spin_lock_irqsave(&newowner->lock, flags);
1015 if (newowner->qnkeys + 1 > maxkeys ||
1016 newowner->qnbytes + key->quotalen > maxbytes ||
1017 newowner->qnbytes + key->quotalen <
1018 newowner->qnbytes)
1019 goto quota_overrun;
1020
1021 newowner->qnkeys++;
1022 newowner->qnbytes += key->quotalen;
1023 spin_unlock_irqrestore(&newowner->lock, flags);
1024
1025 spin_lock_irqsave(&key->user->lock, flags);
1026 key->user->qnkeys--;
1027 key->user->qnbytes -= key->quotalen;
1028 spin_unlock_irqrestore(&key->user->lock, flags);
1029 }
1030
1031 atomic_dec(&key->user->nkeys);
1032 atomic_inc(&newowner->nkeys);
1033
1034 if (key->state != KEY_IS_UNINSTANTIATED) {
1035 atomic_dec(&key->user->nikeys);
1036 atomic_inc(&newowner->nikeys);
1037 }
1038
1039 zapowner = key->user;
1040 key->user = newowner;
1041 key->uid = uid;
1042 }
1043
1044 /* change the GID */
1045 if (group != (gid_t) -1)
1046 key->gid = gid;
1047
1048 notify_key(key, NOTIFY_KEY_SETATTR, 0);
1049 ret = 0;
1050
1051 error_put:
1052 up_write(&key->sem);
1053 key_put(key);
1054 if (zapowner)
1055 key_user_put(zapowner);
1056 error:
1057 return ret;
1058
1059 quota_overrun:
1060 spin_unlock_irqrestore(&newowner->lock, flags);
1061 zapowner = newowner;
1062 ret = -EDQUOT;
1063 goto error_put;
1064 }
1065
1066 /*
1067 * Change the permission mask on a key.
1068 *
1069 * The key must grant the caller Setattr permission for this to work, though
1070 * the key need not be fully instantiated yet. If the caller does not have
1071 * sysadmin capability, it may only change the permission on keys that it owns.
1072 */
1073 long keyctl_setperm_key(key_serial_t id, key_perm_t perm)
1074 {
1075 struct key *key;
1076 key_ref_t key_ref;
1077 long ret;
1078
1079 ret = -EINVAL;
1080 if (perm & ~(KEY_POS_ALL | KEY_USR_ALL | KEY_GRP_ALL | KEY_OTH_ALL))
1081 goto error;
1082
1083 key_ref = lookup_user_key(id, KEY_LOOKUP_CREATE | KEY_LOOKUP_PARTIAL,
1084 KEY_NEED_SETATTR);
1085 if (IS_ERR(key_ref)) {
1086 ret = PTR_ERR(key_ref);
1087 goto error;
1088 }
1089
1090 key = key_ref_to_ptr(key_ref);
1091
1092 /* make the changes with the locks held to prevent chown/chmod races */
1093 ret = -EACCES;
1094 down_write(&key->sem);
1095
1096 /* if we're not the sysadmin, we can only change a key that we own */
1097 if (uid_eq(key->uid, current_fsuid()) || capable(CAP_SYS_ADMIN)) {
1098 key->perm = perm;
1099 notify_key(key, NOTIFY_KEY_SETATTR, 0);
1100 ret = 0;
1101 }
1102
1103 up_write(&key->sem);
1104 key_put(key);
1105 error:
1106 return ret;
1107 }
1108
1109 /*
1110 * Get the destination keyring for instantiation and check that the caller has
1111 * Write permission on it.
1112 */
1113 static long get_instantiation_keyring(key_serial_t ringid,
1114 struct request_key_auth *rka,
1115 struct key **_dest_keyring)
1116 {
1117 key_ref_t dkref;
1118
1119 *_dest_keyring = NULL;
1120
1121 /* just return a NULL pointer if we weren't asked to make a link */
1122 if (ringid == 0)
1123 return 0;
1124
1125 /* if a specific keyring is nominated by ID, then use that */
1126 if (ringid > 0) {
1127 dkref = lookup_user_key(ringid, KEY_LOOKUP_CREATE, KEY_NEED_WRITE);
1128 if (IS_ERR(dkref))
1129 return PTR_ERR(dkref);
1130 *_dest_keyring = key_ref_to_ptr(dkref);
1131 return 0;
1132 }
1133
1134 if (ringid == KEY_SPEC_REQKEY_AUTH_KEY)
1135 return -EINVAL;
1136
1137 /* otherwise specify the destination keyring recorded in the
1138 * authorisation key (any KEY_SPEC_*_KEYRING) */
1139 if (ringid >= KEY_SPEC_REQUESTOR_KEYRING) {
1140 *_dest_keyring = key_get(rka->dest_keyring);
1141 return 0;
1142 }
1143
1144 return -ENOKEY;
1145 }
1146
1147 /*
1148 * Change the request_key authorisation key on the current process.
1149 */
1150 static int keyctl_change_reqkey_auth(struct key *key)
1151 {
1152 struct cred *new;
1153
1154 new = prepare_creds();
1155 if (!new)
1156 return -ENOMEM;
1157
1158 key_put(new->request_key_auth);
1159 new->request_key_auth = key_get(key);
1160
1161 return commit_creds(new);
1162 }
1163
1164 /*
1165 * Instantiate a key with the specified payload and link the key into the
1166 * 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 * If successful, 0 will be returned.
1172 */
1173 static long keyctl_instantiate_key_common(key_serial_t id,
1174 struct iov_iter *from,
1175 key_serial_t ringid)
1176 {
1177 const struct cred *cred = current_cred();
1178 struct request_key_auth *rka;
1179 struct key *instkey, *dest_keyring;
1180 size_t plen = from ? iov_iter_count(from) : 0;
1181 void *payload;
1182 long ret;
1183
1184 kenter("%d,,%zu,%d", id, plen, ringid);
1185
1186 if (!plen)
1187 from = NULL;
1188
1189 ret = -EINVAL;
1190 if (plen > 1024 * 1024 - 1)
1191 goto error;
1192
1193 /* the appropriate instantiation authorisation key must have been
1194 * assumed before calling this */
1195 ret = -EPERM;
1196 instkey = cred->request_key_auth;
1197 if (!instkey)
1198 goto error;
1199
1200 rka = instkey->payload.data[0];
1201 if (rka->target_key->serial != id)
1202 goto error;
1203
1204 /* pull the payload in if one was supplied */
1205 payload = NULL;
1206
1207 if (from) {
1208 ret = -ENOMEM;
1209 payload = kvmalloc(plen, GFP_KERNEL);
1210 if (!payload)
1211 goto error;
1212
1213 ret = -EFAULT;
1214 if (!copy_from_iter_full(payload, plen, from))
1215 goto error2;
1216 }
1217
1218 /* find the destination keyring amongst those belonging to the
1219 * requesting task */
1220 ret = get_instantiation_keyring(ringid, rka, &dest_keyring);
1221 if (ret < 0)
1222 goto error2;
1223
1224 /* instantiate the key and link it into a keyring */
1225 ret = key_instantiate_and_link(rka->target_key, payload, plen,
1226 dest_keyring, instkey);
1227
1228 key_put(dest_keyring);
1229
1230 /* discard the assumed authority if it's just been disabled by
1231 * instantiation of the key */
1232 if (ret == 0)
1233 keyctl_change_reqkey_auth(NULL);
1234
1235 error2:
1236 kvfree_sensitive(payload, plen);
1237 error:
1238 return ret;
1239 }
1240
1241 /*
1242 * Instantiate a key with the specified payload and link the key into the
1243 * destination keyring if one is given.
1244 *
1245 * The caller must have the appropriate instantiation permit set for this to
1246 * work (see keyctl_assume_authority). No other permissions are required.
1247 *
1248 * If successful, 0 will be returned.
1249 */
1250 long keyctl_instantiate_key(key_serial_t id,
1251 const void __user *_payload,
1252 size_t plen,
1253 key_serial_t ringid)
1254 {
1255 if (_payload && plen) {
1256 struct iov_iter from;
1257 int ret;
1258
1259 ret = import_ubuf(ITER_SOURCE, (void __user *)_payload, plen,
1260 &from);
1261 if (unlikely(ret))
1262 return ret;
1263
1264 return keyctl_instantiate_key_common(id, &from, ringid);
1265 }
1266
1267 return keyctl_instantiate_key_common(id, NULL, ringid);
1268 }
1269
1270 /*
1271 * Instantiate a key with the specified multipart payload and link the key into
1272 * the destination keyring if one is given.
1273 *
1274 * The caller must have the appropriate instantiation permit set for this to
1275 * work (see keyctl_assume_authority). No other permissions are required.
1276 *
1277 * If successful, 0 will be returned.
1278 */
1279 long keyctl_instantiate_key_iov(key_serial_t id,
1280 const struct iovec __user *_payload_iov,
1281 unsigned ioc,
1282 key_serial_t ringid)
1283 {
1284 struct iovec iovstack[UIO_FASTIOV], *iov = iovstack;
1285 struct iov_iter from;
1286 long ret;
1287
1288 if (!_payload_iov)
1289 ioc = 0;
1290
1291 ret = import_iovec(ITER_SOURCE, _payload_iov, ioc,
1292 ARRAY_SIZE(iovstack), &iov, &from);
1293 if (ret < 0)
1294 return ret;
1295 ret = keyctl_instantiate_key_common(id, &from, ringid);
1296 kfree(iov);
1297 return ret;
1298 }
1299
1300 /*
1301 * Negatively instantiate the key with the given timeout (in seconds) and link
1302 * the key into the destination keyring if one is given.
1303 *
1304 * The caller must have the appropriate instantiation permit set for this to
1305 * work (see keyctl_assume_authority). No other permissions are required.
1306 *
1307 * The key and any links to the key will be automatically garbage collected
1308 * after the timeout expires.
1309 *
1310 * Negative keys are used to rate limit repeated request_key() calls by causing
1311 * them to return -ENOKEY until the negative key expires.
1312 *
1313 * If successful, 0 will be returned.
1314 */
1315 long keyctl_negate_key(key_serial_t id, unsigned timeout, key_serial_t ringid)
1316 {
1317 return keyctl_reject_key(id, timeout, ENOKEY, ringid);
1318 }
1319
1320 /*
1321 * Negatively instantiate the key with the given timeout (in seconds) and error
1322 * code and link the key into the destination keyring if one is given.
1323 *
1324 * The caller must have the appropriate instantiation permit set for this to
1325 * work (see keyctl_assume_authority). No other permissions are required.
1326 *
1327 * The key and any links to the key will be automatically garbage collected
1328 * after the timeout expires.
1329 *
1330 * Negative keys are used to rate limit repeated request_key() calls by causing
1331 * them to return the specified error code until the negative key expires.
1332 *
1333 * If successful, 0 will be returned.
1334 */
1335 long keyctl_reject_key(key_serial_t id, unsigned timeout, unsigned error,
1336 key_serial_t ringid)
1337 {
1338 const struct cred *cred = current_cred();
1339 struct request_key_auth *rka;
1340 struct key *instkey, *dest_keyring;
1341 long ret;
1342
1343 kenter("%d,%u,%u,%d", id, timeout, error, ringid);
1344
1345 /* must be a valid error code and mustn't be a kernel special */
1346 if (error <= 0 ||
1347 error >= MAX_ERRNO ||
1348 error == ERESTARTSYS ||
1349 error == ERESTARTNOINTR ||
1350 error == ERESTARTNOHAND ||
1351 error == ERESTART_RESTARTBLOCK)
1352 return -EINVAL;
1353
1354 /* the appropriate instantiation authorisation key must have been
1355 * assumed before calling this */
1356 ret = -EPERM;
1357 instkey = cred->request_key_auth;
1358 if (!instkey)
1359 goto error;
1360
1361 rka = instkey->payload.data[0];
1362 if (rka->target_key->serial != id)
1363 goto error;
1364
1365 /* find the destination keyring if present (which must also be
1366 * writable) */
1367 ret = get_instantiation_keyring(ringid, rka, &dest_keyring);
1368 if (ret < 0)
1369 goto error;
1370
1371 /* instantiate the key and link it into a keyring */
1372 ret = key_reject_and_link(rka->target_key, timeout, error,
1373 dest_keyring, instkey);
1374
1375 key_put(dest_keyring);
1376
1377 /* discard the assumed authority if it's just been disabled by
1378 * instantiation of the key */
1379 if (ret == 0)
1380 keyctl_change_reqkey_auth(NULL);
1381
1382 error:
1383 return ret;
1384 }
1385
1386 /*
1387 * Read or set the default keyring in which request_key() will cache keys and
1388 * return the old setting.
1389 *
1390 * If a thread or process keyring is specified then it will be created if it
1391 * doesn't yet exist. The old setting will be returned if successful.
1392 */
1393 long keyctl_set_reqkey_keyring(int reqkey_defl)
1394 {
1395 struct cred *new;
1396 int ret, old_setting;
1397
1398 old_setting = current_cred_xxx(jit_keyring);
1399
1400 if (reqkey_defl == KEY_REQKEY_DEFL_NO_CHANGE)
1401 return old_setting;
1402
1403 new = prepare_creds();
1404 if (!new)
1405 return -ENOMEM;
1406
1407 switch (reqkey_defl) {
1408 case KEY_REQKEY_DEFL_THREAD_KEYRING:
1409 ret = install_thread_keyring_to_cred(new);
1410 if (ret < 0)
1411 goto error;
1412 goto set;
1413
1414 case KEY_REQKEY_DEFL_PROCESS_KEYRING:
1415 ret = install_process_keyring_to_cred(new);
1416 if (ret < 0)
1417 goto error;
1418 goto set;
1419
1420 case KEY_REQKEY_DEFL_DEFAULT:
1421 case KEY_REQKEY_DEFL_SESSION_KEYRING:
1422 case KEY_REQKEY_DEFL_USER_KEYRING:
1423 case KEY_REQKEY_DEFL_USER_SESSION_KEYRING:
1424 case KEY_REQKEY_DEFL_REQUESTOR_KEYRING:
1425 goto set;
1426
1427 case KEY_REQKEY_DEFL_NO_CHANGE:
1428 case KEY_REQKEY_DEFL_GROUP_KEYRING:
1429 default:
1430 ret = -EINVAL;
1431 goto error;
1432 }
1433
1434 set:
1435 new->jit_keyring = reqkey_defl;
1436 commit_creds(new);
1437 return old_setting;
1438 error:
1439 abort_creds(new);
1440 return ret;
1441 }
1442
1443 /*
1444 * Set or clear the timeout on a key.
1445 *
1446 * Either the key must grant the caller Setattr permission or else the caller
1447 * must hold an instantiation authorisation token for the key.
1448 *
1449 * The timeout is either 0 to clear the timeout, or a number of seconds from
1450 * the current time. The key and any links to the key will be automatically
1451 * garbage collected after the timeout expires.
1452 *
1453 * Keys with KEY_FLAG_KEEP set should not be timed out.
1454 *
1455 * If successful, 0 is returned.
1456 */
1457 long keyctl_set_timeout(key_serial_t id, unsigned timeout)
1458 {
1459 struct key *key, *instkey;
1460 key_ref_t key_ref;
1461 long ret;
1462
1463 key_ref = lookup_user_key(id, KEY_LOOKUP_CREATE | KEY_LOOKUP_PARTIAL,
1464 KEY_NEED_SETATTR);
1465 if (IS_ERR(key_ref)) {
1466 /* setting the timeout on a key under construction is permitted
1467 * if we have the authorisation token handy */
1468 if (PTR_ERR(key_ref) == -EACCES) {
1469 instkey = key_get_instantiation_authkey(id);
1470 if (!IS_ERR(instkey)) {
1471 key_put(instkey);
1472 key_ref = lookup_user_key(id,
1473 KEY_LOOKUP_PARTIAL,
1474 KEY_AUTHTOKEN_OVERRIDE);
1475 if (!IS_ERR(key_ref))
1476 goto okay;
1477 }
1478 }
1479
1480 ret = PTR_ERR(key_ref);
1481 goto error;
1482 }
1483
1484 okay:
1485 key = key_ref_to_ptr(key_ref);
1486 ret = 0;
1487 if (test_bit(KEY_FLAG_KEEP, &key->flags)) {
1488 ret = -EPERM;
1489 } else {
1490 key_set_timeout(key, timeout);
1491 notify_key(key, NOTIFY_KEY_SETATTR, 0);
1492 }
1493 key_put(key);
1494
1495 error:
1496 return ret;
1497 }
1498
1499 /*
1500 * Assume (or clear) the authority to instantiate the specified key.
1501 *
1502 * This sets the authoritative token currently in force for key instantiation.
1503 * This must be done for a key to be instantiated. It has the effect of making
1504 * available all the keys from the caller of the request_key() that created a
1505 * key to request_key() calls made by the caller of this function.
1506 *
1507 * The caller must have the instantiation key in their process keyrings with a
1508 * Search permission grant available to the caller.
1509 *
1510 * If the ID given is 0, then the setting will be cleared and 0 returned.
1511 *
1512 * If the ID given has a matching an authorisation key, then that key will be
1513 * set and its ID will be returned. The authorisation key can be read to get
1514 * the callout information passed to request_key().
1515 */
1516 long keyctl_assume_authority(key_serial_t id)
1517 {
1518 struct key *authkey;
1519 long ret;
1520
1521 /* special key IDs aren't permitted */
1522 ret = -EINVAL;
1523 if (id < 0)
1524 goto error;
1525
1526 /* we divest ourselves of authority if given an ID of 0 */
1527 if (id == 0) {
1528 ret = keyctl_change_reqkey_auth(NULL);
1529 goto error;
1530 }
1531
1532 /* attempt to assume the authority temporarily granted to us whilst we
1533 * instantiate the specified key
1534 * - the authorisation key must be in the current task's keyrings
1535 * somewhere
1536 */
1537 authkey = key_get_instantiation_authkey(id);
1538 if (IS_ERR(authkey)) {
1539 ret = PTR_ERR(authkey);
1540 goto error;
1541 }
1542
1543 ret = keyctl_change_reqkey_auth(authkey);
1544 if (ret == 0)
1545 ret = authkey->serial;
1546 key_put(authkey);
1547 error:
1548 return ret;
1549 }
1550
1551 /*
1552 * Get a key's the LSM security label.
1553 *
1554 * The key must grant the caller View permission for this to work.
1555 *
1556 * If there's a buffer, then up to buflen bytes of data will be placed into it.
1557 *
1558 * If successful, the amount of information available will be returned,
1559 * irrespective of how much was copied (including the terminal NUL).
1560 */
1561 long keyctl_get_security(key_serial_t keyid,
1562 char __user *buffer,
1563 size_t buflen)
1564 {
1565 struct key *key, *instkey;
1566 key_ref_t key_ref;
1567 char *context;
1568 long ret;
1569
1570 key_ref = lookup_user_key(keyid, KEY_LOOKUP_PARTIAL, KEY_NEED_VIEW);
1571 if (IS_ERR(key_ref)) {
1572 if (PTR_ERR(key_ref) != -EACCES)
1573 return PTR_ERR(key_ref);
1574
1575 /* viewing a key under construction is also permitted if we
1576 * have the authorisation token handy */
1577 instkey = key_get_instantiation_authkey(keyid);
1578 if (IS_ERR(instkey))
1579 return PTR_ERR(instkey);
1580 key_put(instkey);
1581
1582 key_ref = lookup_user_key(keyid, KEY_LOOKUP_PARTIAL,
1583 KEY_AUTHTOKEN_OVERRIDE);
1584 if (IS_ERR(key_ref))
1585 return PTR_ERR(key_ref);
1586 }
1587
1588 key = key_ref_to_ptr(key_ref);
1589 ret = security_key_getsecurity(key, &context);
1590 if (ret == 0) {
1591 /* if no information was returned, give userspace an empty
1592 * string */
1593 ret = 1;
1594 if (buffer && buflen > 0 &&
1595 copy_to_user(buffer, "", 1) != 0)
1596 ret = -EFAULT;
1597 } else if (ret > 0) {
1598 /* return as much data as there's room for */
1599 if (buffer && buflen > 0) {
1600 if (buflen > ret)
1601 buflen = ret;
1602
1603 if (copy_to_user(buffer, context, buflen) != 0)
1604 ret = -EFAULT;
1605 }
1606
1607 kfree(context);
1608 }
1609
1610 key_ref_put(key_ref);
1611 return ret;
1612 }
1613
1614 /*
1615 * Attempt to install the calling process's session keyring on the process's
1616 * parent process.
1617 *
1618 * The keyring must exist and must grant the caller LINK permission, and the
1619 * parent process must be single-threaded and must have the same effective
1620 * ownership as this process and mustn't be SUID/SGID.
1621 *
1622 * The keyring will be emplaced on the parent when it next resumes userspace.
1623 *
1624 * If successful, 0 will be returned.
1625 */
1626 long keyctl_session_to_parent(void)
1627 {
1628 struct task_struct *me, *parent;
1629 const struct cred *mycred, *pcred;
1630 struct callback_head *newwork, *oldwork;
1631 key_ref_t keyring_r;
1632 struct cred *cred;
1633 int ret;
1634
1635 keyring_r = lookup_user_key(KEY_SPEC_SESSION_KEYRING, 0, KEY_NEED_LINK);
1636 if (IS_ERR(keyring_r))
1637 return PTR_ERR(keyring_r);
1638
1639 ret = -ENOMEM;
1640
1641 /* our parent is going to need a new cred struct, a new tgcred struct
1642 * and new security data, so we allocate them here to prevent ENOMEM in
1643 * our parent */
1644 cred = cred_alloc_blank();
1645 if (!cred)
1646 goto error_keyring;
1647 newwork = &cred->rcu;
1648
1649 cred->session_keyring = key_ref_to_ptr(keyring_r);
1650 keyring_r = NULL;
1651 init_task_work(newwork, key_change_session_keyring);
1652
1653 me = current;
1654 rcu_read_lock();
1655 write_lock_irq(&tasklist_lock);
1656
1657 ret = -EPERM;
1658 oldwork = NULL;
1659 parent = rcu_dereference_protected(me->real_parent,
1660 lockdep_is_held(&tasklist_lock));
1661
1662 /* the parent mustn't be init and mustn't be a kernel thread */
1663 if (parent->pid <= 1 || !parent->mm)
1664 goto unlock;
1665
1666 /* the parent must be single threaded */
1667 if (!thread_group_empty(parent))
1668 goto unlock;
1669
1670 /* the parent and the child must have different session keyrings or
1671 * there's no point */
1672 mycred = current_cred();
1673 pcred = __task_cred(parent);
1674 if (mycred == pcred ||
1675 mycred->session_keyring == pcred->session_keyring) {
1676 ret = 0;
1677 goto unlock;
1678 }
1679
1680 /* the parent must have the same effective ownership and mustn't be
1681 * SUID/SGID */
1682 if (!uid_eq(pcred->uid, mycred->euid) ||
1683 !uid_eq(pcred->euid, mycred->euid) ||
1684 !uid_eq(pcred->suid, mycred->euid) ||
1685 !gid_eq(pcred->gid, mycred->egid) ||
1686 !gid_eq(pcred->egid, mycred->egid) ||
1687 !gid_eq(pcred->sgid, mycred->egid))
1688 goto unlock;
1689
1690 /* the keyrings must have the same UID */
1691 if ((pcred->session_keyring &&
1692 !uid_eq(pcred->session_keyring->uid, mycred->euid)) ||
1693 !uid_eq(mycred->session_keyring->uid, mycred->euid))
1694 goto unlock;
1695
1696 /* cancel an already pending keyring replacement */
1697 oldwork = task_work_cancel_func(parent, key_change_session_keyring);
1698
1699 /* the replacement session keyring is applied just prior to userspace
1700 * restarting */
1701 ret = task_work_add(parent, newwork, TWA_RESUME);
1702 if (!ret)
1703 newwork = NULL;
1704 unlock:
1705 write_unlock_irq(&tasklist_lock);
1706 rcu_read_unlock();
1707 if (oldwork)
1708 put_cred(container_of(oldwork, struct cred, rcu));
1709 if (newwork)
1710 put_cred(cred);
1711 return ret;
1712
1713 error_keyring:
1714 key_ref_put(keyring_r);
1715 return ret;
1716 }
1717
1718 /*
1719 * Apply a restriction to a given keyring.
1720 *
1721 * The caller must have Setattr permission to change keyring restrictions.
1722 *
1723 * The requested type name may be a NULL pointer to reject all attempts
1724 * to link to the keyring. In this case, _restriction must also be NULL.
1725 * Otherwise, both _type and _restriction must be non-NULL.
1726 *
1727 * Returns 0 if successful.
1728 */
1729 long keyctl_restrict_keyring(key_serial_t id, const char __user *_type,
1730 const char __user *_restriction)
1731 {
1732 key_ref_t key_ref;
1733 char type[32];
1734 char *restriction = NULL;
1735 long ret;
1736
1737 key_ref = lookup_user_key(id, 0, KEY_NEED_SETATTR);
1738 if (IS_ERR(key_ref))
1739 return PTR_ERR(key_ref);
1740
1741 ret = -EINVAL;
1742 if (_type) {
1743 if (!_restriction)
1744 goto error;
1745
1746 ret = key_get_type_from_user(type, _type, sizeof(type));
1747 if (ret < 0)
1748 goto error;
1749
1750 restriction = strndup_user(_restriction, PAGE_SIZE);
1751 if (IS_ERR(restriction)) {
1752 ret = PTR_ERR(restriction);
1753 goto error;
1754 }
1755 } else {
1756 if (_restriction)
1757 goto error;
1758 }
1759
1760 ret = keyring_restrict(key_ref, _type ? type : NULL, restriction);
1761 kfree(restriction);
1762 error:
1763 key_ref_put(key_ref);
1764 return ret;
1765 }
1766
1767 #ifdef CONFIG_KEY_NOTIFICATIONS
1768 /*
1769 * Watch for changes to a key.
1770 *
1771 * The caller must have View permission to watch a key or keyring.
1772 */
1773 long keyctl_watch_key(key_serial_t id, int watch_queue_fd, int watch_id)
1774 {
1775 struct watch_queue *wqueue;
1776 struct watch_list *wlist = NULL;
1777 struct watch *watch = NULL;
1778 struct key *key;
1779 key_ref_t key_ref;
1780 long ret;
1781
1782 if (watch_id < -1 || watch_id > 0xff)
1783 return -EINVAL;
1784
1785 key_ref = lookup_user_key(id, KEY_LOOKUP_CREATE, KEY_NEED_VIEW);
1786 if (IS_ERR(key_ref))
1787 return PTR_ERR(key_ref);
1788 key = key_ref_to_ptr(key_ref);
1789
1790 wqueue = get_watch_queue(watch_queue_fd);
1791 if (IS_ERR(wqueue)) {
1792 ret = PTR_ERR(wqueue);
1793 goto err_key;
1794 }
1795
1796 if (watch_id >= 0) {
1797 ret = -ENOMEM;
1798 if (!key->watchers) {
1799 wlist = kzalloc(sizeof(*wlist), GFP_KERNEL);
1800 if (!wlist)
1801 goto err_wqueue;
1802 init_watch_list(wlist, NULL);
1803 }
1804
1805 watch = kzalloc(sizeof(*watch), GFP_KERNEL);
1806 if (!watch)
1807 goto err_wlist;
1808
1809 init_watch(watch, wqueue);
1810 watch->id = key->serial;
1811 watch->info_id = (u32)watch_id << WATCH_INFO_ID__SHIFT;
1812
1813 ret = security_watch_key(key);
1814 if (ret < 0)
1815 goto err_watch;
1816
1817 down_write(&key->sem);
1818 if (!key->watchers) {
1819 key->watchers = wlist;
1820 wlist = NULL;
1821 }
1822
1823 ret = add_watch_to_object(watch, key->watchers);
1824 up_write(&key->sem);
1825
1826 if (ret == 0)
1827 watch = NULL;
1828 } else {
1829 ret = -EBADSLT;
1830 if (key->watchers) {
1831 down_write(&key->sem);
1832 ret = remove_watch_from_object(key->watchers,
1833 wqueue, key_serial(key),
1834 false);
1835 up_write(&key->sem);
1836 }
1837 }
1838
1839 err_watch:
1840 kfree(watch);
1841 err_wlist:
1842 kfree(wlist);
1843 err_wqueue:
1844 put_watch_queue(wqueue);
1845 err_key:
1846 key_put(key);
1847 return ret;
1848 }
1849 #endif /* CONFIG_KEY_NOTIFICATIONS */
1850
1851 /*
1852 * Get keyrings subsystem capabilities.
1853 */
1854 long keyctl_capabilities(unsigned char __user *_buffer, size_t buflen)
1855 {
1856 size_t size = buflen;
1857
1858 if (size > 0) {
1859 if (size > sizeof(keyrings_capabilities))
1860 size = sizeof(keyrings_capabilities);
1861 if (copy_to_user(_buffer, keyrings_capabilities, size) != 0)
1862 return -EFAULT;
1863 if (size < buflen &&
1864 clear_user(_buffer + size, buflen - size) != 0)
1865 return -EFAULT;
1866 }
1867
1868 return sizeof(keyrings_capabilities);
1869 }
1870
1871 /*
1872 * The key control system call
1873 */
1874 SYSCALL_DEFINE5(keyctl, int, option, unsigned long, arg2, unsigned long, arg3,
1875 unsigned long, arg4, unsigned long, arg5)
1876 {
1877 switch (option) {
1878 case KEYCTL_GET_KEYRING_ID:
1879 return keyctl_get_keyring_ID((key_serial_t) arg2,
1880 (int) arg3);
1881
1882 case KEYCTL_JOIN_SESSION_KEYRING:
1883 return keyctl_join_session_keyring((const char __user *) arg2);
1884
1885 case KEYCTL_UPDATE:
1886 return keyctl_update_key((key_serial_t) arg2,
1887 (const void __user *) arg3,
1888 (size_t) arg4);
1889
1890 case KEYCTL_REVOKE:
1891 return keyctl_revoke_key((key_serial_t) arg2);
1892
1893 case KEYCTL_DESCRIBE:
1894 return keyctl_describe_key((key_serial_t) arg2,
1895 (char __user *) arg3,
1896 (unsigned) arg4);
1897
1898 case KEYCTL_CLEAR:
1899 return keyctl_keyring_clear((key_serial_t) arg2);
1900
1901 case KEYCTL_LINK:
1902 return keyctl_keyring_link((key_serial_t) arg2,
1903 (key_serial_t) arg3);
1904
1905 case KEYCTL_UNLINK:
1906 return keyctl_keyring_unlink((key_serial_t) arg2,
1907 (key_serial_t) arg3);
1908
1909 case KEYCTL_SEARCH:
1910 return keyctl_keyring_search((key_serial_t) arg2,
1911 (const char __user *) arg3,
1912 (const char __user *) arg4,
1913 (key_serial_t) arg5);
1914
1915 case KEYCTL_READ:
1916 return keyctl_read_key((key_serial_t) arg2,
1917 (char __user *) arg3,
1918 (size_t) arg4);
1919
1920 case KEYCTL_CHOWN:
1921 return keyctl_chown_key((key_serial_t) arg2,
1922 (uid_t) arg3,
1923 (gid_t) arg4);
1924
1925 case KEYCTL_SETPERM:
1926 return keyctl_setperm_key((key_serial_t) arg2,
1927 (key_perm_t) arg3);
1928
1929 case KEYCTL_INSTANTIATE:
1930 return keyctl_instantiate_key((key_serial_t) arg2,
1931 (const void __user *) arg3,
1932 (size_t) arg4,
1933 (key_serial_t) arg5);
1934
1935 case KEYCTL_NEGATE:
1936 return keyctl_negate_key((key_serial_t) arg2,
1937 (unsigned) arg3,
1938 (key_serial_t) arg4);
1939
1940 case KEYCTL_SET_REQKEY_KEYRING:
1941 return keyctl_set_reqkey_keyring(arg2);
1942
1943 case KEYCTL_SET_TIMEOUT:
1944 return keyctl_set_timeout((key_serial_t) arg2,
1945 (unsigned) arg3);
1946
1947 case KEYCTL_ASSUME_AUTHORITY:
1948 return keyctl_assume_authority((key_serial_t) arg2);
1949
1950 case KEYCTL_GET_SECURITY:
1951 return keyctl_get_security((key_serial_t) arg2,
1952 (char __user *) arg3,
1953 (size_t) arg4);
1954
1955 case KEYCTL_SESSION_TO_PARENT:
1956 return keyctl_session_to_parent();
1957
1958 case KEYCTL_REJECT:
1959 return keyctl_reject_key((key_serial_t) arg2,
1960 (unsigned) arg3,
1961 (unsigned) arg4,
1962 (key_serial_t) arg5);
1963
1964 case KEYCTL_INSTANTIATE_IOV:
1965 return keyctl_instantiate_key_iov(
1966 (key_serial_t) arg2,
1967 (const struct iovec __user *) arg3,
1968 (unsigned) arg4,
1969 (key_serial_t) arg5);
1970
1971 case KEYCTL_INVALIDATE:
1972 return keyctl_invalidate_key((key_serial_t) arg2);
1973
1974 case KEYCTL_GET_PERSISTENT:
1975 return keyctl_get_persistent((uid_t)arg2, (key_serial_t)arg3);
1976
1977 case KEYCTL_DH_COMPUTE:
1978 return keyctl_dh_compute((struct keyctl_dh_params __user *) arg2,
1979 (char __user *) arg3, (size_t) arg4,
1980 (struct keyctl_kdf_params __user *) arg5);
1981
1982 case KEYCTL_RESTRICT_KEYRING:
1983 return keyctl_restrict_keyring((key_serial_t) arg2,
1984 (const char __user *) arg3,
1985 (const char __user *) arg4);
1986
1987 case KEYCTL_PKEY_QUERY:
1988 if (arg3 != 0)
1989 return -EINVAL;
1990 return keyctl_pkey_query((key_serial_t)arg2,
1991 (const char __user *)arg4,
1992 (struct keyctl_pkey_query __user *)arg5);
1993
1994 case KEYCTL_PKEY_ENCRYPT:
1995 case KEYCTL_PKEY_DECRYPT:
1996 case KEYCTL_PKEY_SIGN:
1997 return keyctl_pkey_e_d_s(
1998 option,
1999 (const struct keyctl_pkey_params __user *)arg2,
2000 (const char __user *)arg3,
2001 (const void __user *)arg4,
2002 (void __user *)arg5);
2003
2004 case KEYCTL_PKEY_VERIFY:
2005 return keyctl_pkey_verify(
2006 (const struct keyctl_pkey_params __user *)arg2,
2007 (const char __user *)arg3,
2008 (const void __user *)arg4,
2009 (const void __user *)arg5);
2010
2011 case KEYCTL_MOVE:
2012 return keyctl_keyring_move((key_serial_t)arg2,
2013 (key_serial_t)arg3,
2014 (key_serial_t)arg4,
2015 (unsigned int)arg5);
2016
2017 case KEYCTL_CAPABILITIES:
2018 return keyctl_capabilities((unsigned char __user *)arg2, (size_t)arg3);
2019
2020 case KEYCTL_WATCH_KEY:
2021 return keyctl_watch_key((key_serial_t)arg2, (int)arg3, (int)arg4);
2022
2023 default:
2024 return -EOPNOTSUPP;
2025 }
2026 }
2027
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