1 /* Userspace key control operations
3 * Copyright (C) 2004-5 Red Hat, Inc. All Rights Reserved.
4 * Written by David Howells (dhowells@redhat.com)
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.
12 #include <linux/module.h>
13 #include <linux/init.h>
14 #include <linux/sched.h>
15 #include <linux/sched/task.h>
16 #include <linux/slab.h>
17 #include <linux/syscalls.h>
18 #include <linux/key.h>
19 #include <linux/keyctl.h>
21 #include <linux/capability.h>
22 #include <linux/cred.h>
23 #include <linux/string.h>
24 #include <linux/err.h>
25 #include <linux/vmalloc.h>
26 #include <linux/security.h>
27 #include <linux/uio.h>
28 #include <linux/uaccess.h>
31 #define KEY_MAX_DESC_SIZE 4096
33 static int key_get_type_from_user(char *type
,
34 const char __user
*_type
,
39 ret
= strncpy_from_user(type
, _type
, len
);
42 if (ret
== 0 || ret
>= len
)
51 * Extract the description of a new key from userspace and either add it as a
52 * new key to the specified keyring or update a matching key in that keyring.
54 * If the description is NULL or an empty string, the key type is asked to
55 * generate one from the payload.
57 * The keyring must be writable so that we can attach the key to it.
59 * If successful, the new key's serial number is returned, otherwise an error
62 SYSCALL_DEFINE5(add_key
, const char __user
*, _type
,
63 const char __user
*, _description
,
64 const void __user
*, _payload
,
68 key_ref_t keyring_ref
, key_ref
;
69 char type
[32], *description
;
74 if (plen
> 1024 * 1024 - 1)
77 /* draw all the data into kernel space */
78 ret
= key_get_type_from_user(type
, _type
, sizeof(type
));
84 description
= strndup_user(_description
, KEY_MAX_DESC_SIZE
);
85 if (IS_ERR(description
)) {
86 ret
= PTR_ERR(description
);
92 } else if ((description
[0] == '.') &&
93 (strncmp(type
, "keyring", 7) == 0)) {
99 /* pull the payload in if one was supplied */
104 payload
= kmalloc(plen
, GFP_KERNEL
| __GFP_NOWARN
);
106 if (plen
<= PAGE_SIZE
)
108 payload
= vmalloc(plen
);
114 if (copy_from_user(payload
, _payload
, plen
) != 0)
118 /* find the target keyring (which must be writable) */
119 keyring_ref
= lookup_user_key(ringid
, KEY_LOOKUP_CREATE
, KEY_NEED_WRITE
);
120 if (IS_ERR(keyring_ref
)) {
121 ret
= PTR_ERR(keyring_ref
);
125 /* create or update the requested key and add it to the target
127 key_ref
= key_create_or_update(keyring_ref
, type
, description
,
128 payload
, plen
, KEY_PERM_UNDEF
,
130 if (!IS_ERR(key_ref
)) {
131 ret
= key_ref_to_ptr(key_ref
)->serial
;
132 key_ref_put(key_ref
);
135 ret
= PTR_ERR(key_ref
);
138 key_ref_put(keyring_ref
);
148 * Search the process keyrings and keyring trees linked from those for a
149 * matching key. Keyrings must have appropriate Search permission to be
152 * If a key is found, it will be attached to the destination keyring if there's
153 * one specified and the serial number of the key will be returned.
155 * If no key is found, /sbin/request-key will be invoked if _callout_info is
156 * non-NULL in an attempt to create a key. The _callout_info string will be
157 * passed to /sbin/request-key to aid with completing the request. If the
158 * _callout_info string is "" then it will be changed to "-".
160 SYSCALL_DEFINE4(request_key
, const char __user
*, _type
,
161 const char __user
*, _description
,
162 const char __user
*, _callout_info
,
163 key_serial_t
, destringid
)
165 struct key_type
*ktype
;
169 char type
[32], *description
, *callout_info
;
172 /* pull the type into kernel space */
173 ret
= key_get_type_from_user(type
, _type
, sizeof(type
));
177 /* pull the description into kernel space */
178 description
= strndup_user(_description
, KEY_MAX_DESC_SIZE
);
179 if (IS_ERR(description
)) {
180 ret
= PTR_ERR(description
);
184 /* pull the callout info into kernel space */
188 callout_info
= strndup_user(_callout_info
, PAGE_SIZE
);
189 if (IS_ERR(callout_info
)) {
190 ret
= PTR_ERR(callout_info
);
193 callout_len
= strlen(callout_info
);
196 /* get the destination keyring if specified */
199 dest_ref
= lookup_user_key(destringid
, KEY_LOOKUP_CREATE
,
201 if (IS_ERR(dest_ref
)) {
202 ret
= PTR_ERR(dest_ref
);
207 /* find the key type */
208 ktype
= key_type_lookup(type
);
210 ret
= PTR_ERR(ktype
);
215 key
= request_key_and_link(ktype
, description
, callout_info
,
216 callout_len
, NULL
, key_ref_to_ptr(dest_ref
),
223 /* wait for the key to finish being constructed */
224 ret
= wait_for_key_construction(key
, 1);
235 key_ref_put(dest_ref
);
245 * Get the ID of the specified process keyring.
247 * The requested keyring must have search permission to be found.
249 * If successful, the ID of the requested keyring will be returned.
251 long keyctl_get_keyring_ID(key_serial_t id
, int create
)
254 unsigned long lflags
;
257 lflags
= create
? KEY_LOOKUP_CREATE
: 0;
258 key_ref
= lookup_user_key(id
, lflags
, KEY_NEED_SEARCH
);
259 if (IS_ERR(key_ref
)) {
260 ret
= PTR_ERR(key_ref
);
264 ret
= key_ref_to_ptr(key_ref
)->serial
;
265 key_ref_put(key_ref
);
271 * Join a (named) session keyring.
273 * Create and join an anonymous session keyring or join a named session
274 * keyring, creating it if necessary. A named session keyring must have Search
275 * permission for it to be joined. Session keyrings without this permit will
276 * be skipped over. It is not permitted for userspace to create or join
277 * keyrings whose name begin with a dot.
279 * If successful, the ID of the joined session keyring will be returned.
281 long keyctl_join_session_keyring(const char __user
*_name
)
286 /* fetch the name from userspace */
289 name
= strndup_user(_name
, KEY_MAX_DESC_SIZE
);
300 /* join the session */
301 ret
= join_session_keyring(name
);
309 * Update a key's data payload from the given data.
311 * The key must grant the caller Write permission and the key type must support
312 * updating for this to work. A negative key can be positively instantiated
315 * If successful, 0 will be returned. If the key type does not support
316 * updating, then -EOPNOTSUPP will be returned.
318 long keyctl_update_key(key_serial_t id
,
319 const void __user
*_payload
,
327 if (plen
> PAGE_SIZE
)
330 /* pull the payload in if one was supplied */
334 payload
= kmalloc(plen
, GFP_KERNEL
);
339 if (copy_from_user(payload
, _payload
, plen
) != 0)
343 /* find the target key (which must be writable) */
344 key_ref
= lookup_user_key(id
, 0, KEY_NEED_WRITE
);
345 if (IS_ERR(key_ref
)) {
346 ret
= PTR_ERR(key_ref
);
351 ret
= key_update(key_ref
, payload
, plen
);
353 key_ref_put(key_ref
);
363 * The key must be grant the caller Write or Setattr permission for this to
364 * work. The key type should give up its quota claim when revoked. The key
365 * and any links to the key will be automatically garbage collected after a
366 * certain amount of time (/proc/sys/kernel/keys/gc_delay).
368 * Keys with KEY_FLAG_KEEP set should not be revoked.
370 * If successful, 0 is returned.
372 long keyctl_revoke_key(key_serial_t id
)
378 key_ref
= lookup_user_key(id
, 0, KEY_NEED_WRITE
);
379 if (IS_ERR(key_ref
)) {
380 ret
= PTR_ERR(key_ref
);
383 key_ref
= lookup_user_key(id
, 0, KEY_NEED_SETATTR
);
384 if (IS_ERR(key_ref
)) {
385 ret
= PTR_ERR(key_ref
);
390 key
= key_ref_to_ptr(key_ref
);
392 if (test_bit(KEY_FLAG_KEEP
, &key
->flags
))
397 key_ref_put(key_ref
);
405 * The key must be grant the caller Invalidate permission for this to work.
406 * The key and any links to the key will be automatically garbage collected
409 * Keys with KEY_FLAG_KEEP set should not be invalidated.
411 * If successful, 0 is returned.
413 long keyctl_invalidate_key(key_serial_t id
)
421 key_ref
= lookup_user_key(id
, 0, KEY_NEED_SEARCH
);
422 if (IS_ERR(key_ref
)) {
423 ret
= PTR_ERR(key_ref
);
425 /* Root is permitted to invalidate certain special keys */
426 if (capable(CAP_SYS_ADMIN
)) {
427 key_ref
= lookup_user_key(id
, 0, 0);
430 if (test_bit(KEY_FLAG_ROOT_CAN_INVAL
,
431 &key_ref_to_ptr(key_ref
)->flags
))
440 key
= key_ref_to_ptr(key_ref
);
442 if (test_bit(KEY_FLAG_KEEP
, &key
->flags
))
447 key_ref_put(key_ref
);
449 kleave(" = %ld", ret
);
454 * Clear the specified keyring, creating an empty process keyring if one of the
455 * special keyring IDs is used.
457 * The keyring must grant the caller Write permission and not have
458 * KEY_FLAG_KEEP set for this to work. If successful, 0 will be returned.
460 long keyctl_keyring_clear(key_serial_t ringid
)
462 key_ref_t keyring_ref
;
466 keyring_ref
= lookup_user_key(ringid
, KEY_LOOKUP_CREATE
, KEY_NEED_WRITE
);
467 if (IS_ERR(keyring_ref
)) {
468 ret
= PTR_ERR(keyring_ref
);
470 /* Root is permitted to invalidate certain special keyrings */
471 if (capable(CAP_SYS_ADMIN
)) {
472 keyring_ref
= lookup_user_key(ringid
, 0, 0);
473 if (IS_ERR(keyring_ref
))
475 if (test_bit(KEY_FLAG_ROOT_CAN_CLEAR
,
476 &key_ref_to_ptr(keyring_ref
)->flags
))
485 keyring
= key_ref_to_ptr(keyring_ref
);
486 if (test_bit(KEY_FLAG_KEEP
, &keyring
->flags
))
489 ret
= keyring_clear(keyring
);
491 key_ref_put(keyring_ref
);
497 * Create a link from a keyring to a key if there's no matching key in the
498 * keyring, otherwise replace the link to the matching key with a link to the
501 * The key must grant the caller Link permission and the the keyring must grant
502 * the caller Write permission. Furthermore, if an additional link is created,
503 * the keyring's quota will be extended.
505 * If successful, 0 will be returned.
507 long keyctl_keyring_link(key_serial_t id
, key_serial_t ringid
)
509 key_ref_t keyring_ref
, key_ref
;
512 keyring_ref
= lookup_user_key(ringid
, KEY_LOOKUP_CREATE
, KEY_NEED_WRITE
);
513 if (IS_ERR(keyring_ref
)) {
514 ret
= PTR_ERR(keyring_ref
);
518 key_ref
= lookup_user_key(id
, KEY_LOOKUP_CREATE
, KEY_NEED_LINK
);
519 if (IS_ERR(key_ref
)) {
520 ret
= PTR_ERR(key_ref
);
524 ret
= key_link(key_ref_to_ptr(keyring_ref
), key_ref_to_ptr(key_ref
));
526 key_ref_put(key_ref
);
528 key_ref_put(keyring_ref
);
534 * Unlink a key from a keyring.
536 * The keyring must grant the caller Write permission for this to work; the key
537 * itself need not grant the caller anything. If the last link to a key is
538 * removed then that key will be scheduled for destruction.
540 * Keys or keyrings with KEY_FLAG_KEEP set should not be unlinked.
542 * If successful, 0 will be returned.
544 long keyctl_keyring_unlink(key_serial_t id
, key_serial_t ringid
)
546 key_ref_t keyring_ref
, key_ref
;
547 struct key
*keyring
, *key
;
550 keyring_ref
= lookup_user_key(ringid
, 0, KEY_NEED_WRITE
);
551 if (IS_ERR(keyring_ref
)) {
552 ret
= PTR_ERR(keyring_ref
);
556 key_ref
= lookup_user_key(id
, KEY_LOOKUP_FOR_UNLINK
, 0);
557 if (IS_ERR(key_ref
)) {
558 ret
= PTR_ERR(key_ref
);
562 keyring
= key_ref_to_ptr(keyring_ref
);
563 key
= key_ref_to_ptr(key_ref
);
564 if (test_bit(KEY_FLAG_KEEP
, &keyring
->flags
) &&
565 test_bit(KEY_FLAG_KEEP
, &key
->flags
))
568 ret
= key_unlink(keyring
, key
);
570 key_ref_put(key_ref
);
572 key_ref_put(keyring_ref
);
578 * Return a description of a key to userspace.
580 * The key must grant the caller View permission for this to work.
582 * If there's a buffer, we place up to buflen bytes of data into it formatted
583 * in the following way:
585 * type;uid;gid;perm;description<NUL>
587 * If successful, we return the amount of description available, irrespective
588 * of how much we may have copied into the buffer.
590 long keyctl_describe_key(key_serial_t keyid
,
594 struct key
*key
, *instkey
;
598 int desclen
, infolen
;
600 key_ref
= lookup_user_key(keyid
, KEY_LOOKUP_PARTIAL
, KEY_NEED_VIEW
);
601 if (IS_ERR(key_ref
)) {
602 /* viewing a key under construction is permitted if we have the
603 * authorisation token handy */
604 if (PTR_ERR(key_ref
) == -EACCES
) {
605 instkey
= key_get_instantiation_authkey(keyid
);
606 if (!IS_ERR(instkey
)) {
608 key_ref
= lookup_user_key(keyid
,
611 if (!IS_ERR(key_ref
))
616 ret
= PTR_ERR(key_ref
);
621 key
= key_ref_to_ptr(key_ref
);
622 desclen
= strlen(key
->description
);
624 /* calculate how much information we're going to return */
626 infobuf
= kasprintf(GFP_KERNEL
,
629 from_kuid_munged(current_user_ns(), key
->uid
),
630 from_kgid_munged(current_user_ns(), key
->gid
),
634 infolen
= strlen(infobuf
);
635 ret
= infolen
+ desclen
+ 1;
637 /* consider returning the data */
638 if (buffer
&& buflen
>= ret
) {
639 if (copy_to_user(buffer
, infobuf
, infolen
) != 0 ||
640 copy_to_user(buffer
+ infolen
, key
->description
,
647 key_ref_put(key_ref
);
653 * Search the specified keyring and any keyrings it links to for a matching
654 * key. Only keyrings that grant the caller Search permission will be searched
655 * (this includes the starting keyring). Only keys with Search permission can
658 * If successful, the found key will be linked to the destination keyring if
659 * supplied and the key has Link permission, and the found key ID will be
662 long keyctl_keyring_search(key_serial_t ringid
,
663 const char __user
*_type
,
664 const char __user
*_description
,
665 key_serial_t destringid
)
667 struct key_type
*ktype
;
668 key_ref_t keyring_ref
, key_ref
, dest_ref
;
669 char type
[32], *description
;
672 /* pull the type and description into kernel space */
673 ret
= key_get_type_from_user(type
, _type
, sizeof(type
));
677 description
= strndup_user(_description
, KEY_MAX_DESC_SIZE
);
678 if (IS_ERR(description
)) {
679 ret
= PTR_ERR(description
);
683 /* get the keyring at which to begin the search */
684 keyring_ref
= lookup_user_key(ringid
, 0, KEY_NEED_SEARCH
);
685 if (IS_ERR(keyring_ref
)) {
686 ret
= PTR_ERR(keyring_ref
);
690 /* get the destination keyring if specified */
693 dest_ref
= lookup_user_key(destringid
, KEY_LOOKUP_CREATE
,
695 if (IS_ERR(dest_ref
)) {
696 ret
= PTR_ERR(dest_ref
);
701 /* find the key type */
702 ktype
= key_type_lookup(type
);
704 ret
= PTR_ERR(ktype
);
709 key_ref
= keyring_search(keyring_ref
, ktype
, description
);
710 if (IS_ERR(key_ref
)) {
711 ret
= PTR_ERR(key_ref
);
713 /* treat lack or presence of a negative key the same */
719 /* link the resulting key to the destination keyring if we can */
721 ret
= key_permission(key_ref
, KEY_NEED_LINK
);
725 ret
= key_link(key_ref_to_ptr(dest_ref
), key_ref_to_ptr(key_ref
));
730 ret
= key_ref_to_ptr(key_ref
)->serial
;
733 key_ref_put(key_ref
);
737 key_ref_put(dest_ref
);
739 key_ref_put(keyring_ref
);
747 * Read a key's payload.
749 * The key must either grant the caller Read permission, or it must grant the
750 * caller Search permission when searched for from the process keyrings.
752 * If successful, we place up to buflen bytes of data into the buffer, if one
753 * is provided, and return the amount of data that is available in the key,
754 * irrespective of how much we copied into the buffer.
756 long keyctl_read_key(key_serial_t keyid
, char __user
*buffer
, size_t buflen
)
762 /* find the key first */
763 key_ref
= lookup_user_key(keyid
, 0, 0);
764 if (IS_ERR(key_ref
)) {
769 key
= key_ref_to_ptr(key_ref
);
771 /* see if we can read it directly */
772 ret
= key_permission(key_ref
, KEY_NEED_READ
);
778 /* we can't; see if it's searchable from this process's keyrings
779 * - we automatically take account of the fact that it may be
780 * dangling off an instantiation key
782 if (!is_key_possessed(key_ref
)) {
787 /* the key is probably readable - now try to read it */
790 if (key
->type
->read
) {
791 /* Read the data with the semaphore held (since we might sleep)
792 * to protect against the key being updated or revoked.
794 down_read(&key
->sem
);
795 ret
= key_validate(key
);
797 ret
= key
->type
->read(key
, buffer
, buflen
);
808 * Change the ownership of a key
810 * The key must grant the caller Setattr permission for this to work, though
811 * the key need not be fully instantiated yet. For the UID to be changed, or
812 * for the GID to be changed to a group the caller is not a member of, the
813 * caller must have sysadmin capability. If either uid or gid is -1 then that
814 * attribute is not changed.
816 * If the UID is to be changed, the new user must have sufficient quota to
817 * accept the key. The quota deduction will be removed from the old user to
818 * the new user should the attribute be changed.
820 * If successful, 0 will be returned.
822 long keyctl_chown_key(key_serial_t id
, uid_t user
, gid_t group
)
824 struct key_user
*newowner
, *zapowner
= NULL
;
831 uid
= make_kuid(current_user_ns(), user
);
832 gid
= make_kgid(current_user_ns(), group
);
834 if ((user
!= (uid_t
) -1) && !uid_valid(uid
))
836 if ((group
!= (gid_t
) -1) && !gid_valid(gid
))
840 if (user
== (uid_t
) -1 && group
== (gid_t
) -1)
843 key_ref
= lookup_user_key(id
, KEY_LOOKUP_CREATE
| KEY_LOOKUP_PARTIAL
,
845 if (IS_ERR(key_ref
)) {
846 ret
= PTR_ERR(key_ref
);
850 key
= key_ref_to_ptr(key_ref
);
852 /* make the changes with the locks held to prevent chown/chown races */
854 down_write(&key
->sem
);
856 if (!capable(CAP_SYS_ADMIN
)) {
857 /* only the sysadmin can chown a key to some other UID */
858 if (user
!= (uid_t
) -1 && !uid_eq(key
->uid
, uid
))
861 /* only the sysadmin can set the key's GID to a group other
862 * than one of those that the current process subscribes to */
863 if (group
!= (gid_t
) -1 && !gid_eq(gid
, key
->gid
) && !in_group_p(gid
))
868 if (user
!= (uid_t
) -1 && !uid_eq(uid
, key
->uid
)) {
870 newowner
= key_user_lookup(uid
);
874 /* transfer the quota burden to the new user */
875 if (test_bit(KEY_FLAG_IN_QUOTA
, &key
->flags
)) {
876 unsigned maxkeys
= uid_eq(uid
, GLOBAL_ROOT_UID
) ?
877 key_quota_root_maxkeys
: key_quota_maxkeys
;
878 unsigned maxbytes
= uid_eq(uid
, GLOBAL_ROOT_UID
) ?
879 key_quota_root_maxbytes
: key_quota_maxbytes
;
881 spin_lock(&newowner
->lock
);
882 if (newowner
->qnkeys
+ 1 >= maxkeys
||
883 newowner
->qnbytes
+ key
->quotalen
>= maxbytes
||
884 newowner
->qnbytes
+ key
->quotalen
<
889 newowner
->qnbytes
+= key
->quotalen
;
890 spin_unlock(&newowner
->lock
);
892 spin_lock(&key
->user
->lock
);
894 key
->user
->qnbytes
-= key
->quotalen
;
895 spin_unlock(&key
->user
->lock
);
898 atomic_dec(&key
->user
->nkeys
);
899 atomic_inc(&newowner
->nkeys
);
901 if (test_bit(KEY_FLAG_INSTANTIATED
, &key
->flags
)) {
902 atomic_dec(&key
->user
->nikeys
);
903 atomic_inc(&newowner
->nikeys
);
906 zapowner
= key
->user
;
907 key
->user
= newowner
;
912 if (group
!= (gid_t
) -1)
921 key_user_put(zapowner
);
926 spin_unlock(&newowner
->lock
);
933 * Change the permission mask on a key.
935 * The key must grant the caller Setattr permission for this to work, though
936 * the key need not be fully instantiated yet. If the caller does not have
937 * sysadmin capability, it may only change the permission on keys that it owns.
939 long keyctl_setperm_key(key_serial_t id
, key_perm_t perm
)
946 if (perm
& ~(KEY_POS_ALL
| KEY_USR_ALL
| KEY_GRP_ALL
| KEY_OTH_ALL
))
949 key_ref
= lookup_user_key(id
, KEY_LOOKUP_CREATE
| KEY_LOOKUP_PARTIAL
,
951 if (IS_ERR(key_ref
)) {
952 ret
= PTR_ERR(key_ref
);
956 key
= key_ref_to_ptr(key_ref
);
958 /* make the changes with the locks held to prevent chown/chmod races */
960 down_write(&key
->sem
);
962 /* if we're not the sysadmin, we can only change a key that we own */
963 if (capable(CAP_SYS_ADMIN
) || uid_eq(key
->uid
, current_fsuid())) {
975 * Get the destination keyring for instantiation and check that the caller has
976 * Write permission on it.
978 static long get_instantiation_keyring(key_serial_t ringid
,
979 struct request_key_auth
*rka
,
980 struct key
**_dest_keyring
)
984 *_dest_keyring
= NULL
;
986 /* just return a NULL pointer if we weren't asked to make a link */
990 /* if a specific keyring is nominated by ID, then use that */
992 dkref
= lookup_user_key(ringid
, KEY_LOOKUP_CREATE
, KEY_NEED_WRITE
);
994 return PTR_ERR(dkref
);
995 *_dest_keyring
= key_ref_to_ptr(dkref
);
999 if (ringid
== KEY_SPEC_REQKEY_AUTH_KEY
)
1002 /* otherwise specify the destination keyring recorded in the
1003 * authorisation key (any KEY_SPEC_*_KEYRING) */
1004 if (ringid
>= KEY_SPEC_REQUESTOR_KEYRING
) {
1005 *_dest_keyring
= key_get(rka
->dest_keyring
);
1013 * Change the request_key authorisation key on the current process.
1015 static int keyctl_change_reqkey_auth(struct key
*key
)
1019 new = prepare_creds();
1023 key_put(new->request_key_auth
);
1024 new->request_key_auth
= key_get(key
);
1026 return commit_creds(new);
1030 * Instantiate a key with the specified payload and link the key into the
1031 * destination keyring if one is given.
1033 * The caller must have the appropriate instantiation permit set for this to
1034 * work (see keyctl_assume_authority). No other permissions are required.
1036 * If successful, 0 will be returned.
1038 long keyctl_instantiate_key_common(key_serial_t id
,
1039 struct iov_iter
*from
,
1040 key_serial_t ringid
)
1042 const struct cred
*cred
= current_cred();
1043 struct request_key_auth
*rka
;
1044 struct key
*instkey
, *dest_keyring
;
1045 size_t plen
= from
? iov_iter_count(from
) : 0;
1049 kenter("%d,,%zu,%d", id
, plen
, ringid
);
1055 if (plen
> 1024 * 1024 - 1)
1058 /* the appropriate instantiation authorisation key must have been
1059 * assumed before calling this */
1061 instkey
= cred
->request_key_auth
;
1065 rka
= instkey
->payload
.data
[0];
1066 if (rka
->target_key
->serial
!= id
)
1069 /* pull the payload in if one was supplied */
1074 payload
= kmalloc(plen
, GFP_KERNEL
);
1076 if (plen
<= PAGE_SIZE
)
1078 payload
= vmalloc(plen
);
1084 if (!copy_from_iter_full(payload
, plen
, from
))
1088 /* find the destination keyring amongst those belonging to the
1089 * requesting task */
1090 ret
= get_instantiation_keyring(ringid
, rka
, &dest_keyring
);
1094 /* instantiate the key and link it into a keyring */
1095 ret
= key_instantiate_and_link(rka
->target_key
, payload
, plen
,
1096 dest_keyring
, instkey
);
1098 key_put(dest_keyring
);
1100 /* discard the assumed authority if it's just been disabled by
1101 * instantiation of the key */
1103 keyctl_change_reqkey_auth(NULL
);
1112 * Instantiate a key with the specified payload and link the key into the
1113 * destination keyring if one is given.
1115 * The caller must have the appropriate instantiation permit set for this to
1116 * work (see keyctl_assume_authority). No other permissions are required.
1118 * If successful, 0 will be returned.
1120 long keyctl_instantiate_key(key_serial_t id
,
1121 const void __user
*_payload
,
1123 key_serial_t ringid
)
1125 if (_payload
&& plen
) {
1127 struct iov_iter from
;
1130 ret
= import_single_range(WRITE
, (void __user
*)_payload
, plen
,
1135 return keyctl_instantiate_key_common(id
, &from
, ringid
);
1138 return keyctl_instantiate_key_common(id
, NULL
, ringid
);
1142 * Instantiate a key with the specified multipart payload and link the key into
1143 * the destination keyring if one is given.
1145 * The caller must have the appropriate instantiation permit set for this to
1146 * work (see keyctl_assume_authority). No other permissions are required.
1148 * If successful, 0 will be returned.
1150 long keyctl_instantiate_key_iov(key_serial_t id
,
1151 const struct iovec __user
*_payload_iov
,
1153 key_serial_t ringid
)
1155 struct iovec iovstack
[UIO_FASTIOV
], *iov
= iovstack
;
1156 struct iov_iter from
;
1162 ret
= import_iovec(WRITE
, _payload_iov
, ioc
,
1163 ARRAY_SIZE(iovstack
), &iov
, &from
);
1166 ret
= keyctl_instantiate_key_common(id
, &from
, ringid
);
1172 * Negatively instantiate the key with the given timeout (in seconds) and link
1173 * the key into the destination keyring if one is given.
1175 * The caller must have the appropriate instantiation permit set for this to
1176 * work (see keyctl_assume_authority). No other permissions are required.
1178 * The key and any links to the key will be automatically garbage collected
1179 * after the timeout expires.
1181 * Negative keys are used to rate limit repeated request_key() calls by causing
1182 * them to return -ENOKEY until the negative key expires.
1184 * If successful, 0 will be returned.
1186 long keyctl_negate_key(key_serial_t id
, unsigned timeout
, key_serial_t ringid
)
1188 return keyctl_reject_key(id
, timeout
, ENOKEY
, ringid
);
1192 * Negatively instantiate the key with the given timeout (in seconds) and error
1193 * code and link the key into the destination keyring if one is given.
1195 * The caller must have the appropriate instantiation permit set for this to
1196 * work (see keyctl_assume_authority). No other permissions are required.
1198 * The key and any links to the key will be automatically garbage collected
1199 * after the timeout expires.
1201 * Negative keys are used to rate limit repeated request_key() calls by causing
1202 * them to return the specified error code until the negative key expires.
1204 * If successful, 0 will be returned.
1206 long keyctl_reject_key(key_serial_t id
, unsigned timeout
, unsigned error
,
1207 key_serial_t ringid
)
1209 const struct cred
*cred
= current_cred();
1210 struct request_key_auth
*rka
;
1211 struct key
*instkey
, *dest_keyring
;
1214 kenter("%d,%u,%u,%d", id
, timeout
, error
, ringid
);
1216 /* must be a valid error code and mustn't be a kernel special */
1218 error
>= MAX_ERRNO
||
1219 error
== ERESTARTSYS
||
1220 error
== ERESTARTNOINTR
||
1221 error
== ERESTARTNOHAND
||
1222 error
== ERESTART_RESTARTBLOCK
)
1225 /* the appropriate instantiation authorisation key must have been
1226 * assumed before calling this */
1228 instkey
= cred
->request_key_auth
;
1232 rka
= instkey
->payload
.data
[0];
1233 if (rka
->target_key
->serial
!= id
)
1236 /* find the destination keyring if present (which must also be
1238 ret
= get_instantiation_keyring(ringid
, rka
, &dest_keyring
);
1242 /* instantiate the key and link it into a keyring */
1243 ret
= key_reject_and_link(rka
->target_key
, timeout
, error
,
1244 dest_keyring
, instkey
);
1246 key_put(dest_keyring
);
1248 /* discard the assumed authority if it's just been disabled by
1249 * instantiation of the key */
1251 keyctl_change_reqkey_auth(NULL
);
1258 * Read or set the default keyring in which request_key() will cache keys and
1259 * return the old setting.
1261 * If a thread or process keyring is specified then it will be created if it
1262 * doesn't yet exist. The old setting will be returned if successful.
1264 long keyctl_set_reqkey_keyring(int reqkey_defl
)
1267 int ret
, old_setting
;
1269 old_setting
= current_cred_xxx(jit_keyring
);
1271 if (reqkey_defl
== KEY_REQKEY_DEFL_NO_CHANGE
)
1274 new = prepare_creds();
1278 switch (reqkey_defl
) {
1279 case KEY_REQKEY_DEFL_THREAD_KEYRING
:
1280 ret
= install_thread_keyring_to_cred(new);
1285 case KEY_REQKEY_DEFL_PROCESS_KEYRING
:
1286 ret
= install_process_keyring_to_cred(new);
1291 case KEY_REQKEY_DEFL_DEFAULT
:
1292 case KEY_REQKEY_DEFL_SESSION_KEYRING
:
1293 case KEY_REQKEY_DEFL_USER_KEYRING
:
1294 case KEY_REQKEY_DEFL_USER_SESSION_KEYRING
:
1295 case KEY_REQKEY_DEFL_REQUESTOR_KEYRING
:
1298 case KEY_REQKEY_DEFL_NO_CHANGE
:
1299 case KEY_REQKEY_DEFL_GROUP_KEYRING
:
1306 new->jit_keyring
= reqkey_defl
;
1315 * Set or clear the timeout on a key.
1317 * Either the key must grant the caller Setattr permission or else the caller
1318 * must hold an instantiation authorisation token for the key.
1320 * The timeout is either 0 to clear the timeout, or a number of seconds from
1321 * the current time. The key and any links to the key will be automatically
1322 * garbage collected after the timeout expires.
1324 * Keys with KEY_FLAG_KEEP set should not be timed out.
1326 * If successful, 0 is returned.
1328 long keyctl_set_timeout(key_serial_t id
, unsigned timeout
)
1330 struct key
*key
, *instkey
;
1334 key_ref
= lookup_user_key(id
, KEY_LOOKUP_CREATE
| KEY_LOOKUP_PARTIAL
,
1336 if (IS_ERR(key_ref
)) {
1337 /* setting the timeout on a key under construction is permitted
1338 * if we have the authorisation token handy */
1339 if (PTR_ERR(key_ref
) == -EACCES
) {
1340 instkey
= key_get_instantiation_authkey(id
);
1341 if (!IS_ERR(instkey
)) {
1343 key_ref
= lookup_user_key(id
,
1346 if (!IS_ERR(key_ref
))
1351 ret
= PTR_ERR(key_ref
);
1356 key
= key_ref_to_ptr(key_ref
);
1358 if (test_bit(KEY_FLAG_KEEP
, &key
->flags
))
1361 key_set_timeout(key
, timeout
);
1369 * Assume (or clear) the authority to instantiate the specified key.
1371 * This sets the authoritative token currently in force for key instantiation.
1372 * This must be done for a key to be instantiated. It has the effect of making
1373 * available all the keys from the caller of the request_key() that created a
1374 * key to request_key() calls made by the caller of this function.
1376 * The caller must have the instantiation key in their process keyrings with a
1377 * Search permission grant available to the caller.
1379 * If the ID given is 0, then the setting will be cleared and 0 returned.
1381 * If the ID given has a matching an authorisation key, then that key will be
1382 * set and its ID will be returned. The authorisation key can be read to get
1383 * the callout information passed to request_key().
1385 long keyctl_assume_authority(key_serial_t id
)
1387 struct key
*authkey
;
1390 /* special key IDs aren't permitted */
1395 /* we divest ourselves of authority if given an ID of 0 */
1397 ret
= keyctl_change_reqkey_auth(NULL
);
1401 /* attempt to assume the authority temporarily granted to us whilst we
1402 * instantiate the specified key
1403 * - the authorisation key must be in the current task's keyrings
1406 authkey
= key_get_instantiation_authkey(id
);
1407 if (IS_ERR(authkey
)) {
1408 ret
= PTR_ERR(authkey
);
1412 ret
= keyctl_change_reqkey_auth(authkey
);
1417 ret
= authkey
->serial
;
1423 * Get a key's the LSM security label.
1425 * The key must grant the caller View permission for this to work.
1427 * If there's a buffer, then up to buflen bytes of data will be placed into it.
1429 * If successful, the amount of information available will be returned,
1430 * irrespective of how much was copied (including the terminal NUL).
1432 long keyctl_get_security(key_serial_t keyid
,
1433 char __user
*buffer
,
1436 struct key
*key
, *instkey
;
1441 key_ref
= lookup_user_key(keyid
, KEY_LOOKUP_PARTIAL
, KEY_NEED_VIEW
);
1442 if (IS_ERR(key_ref
)) {
1443 if (PTR_ERR(key_ref
) != -EACCES
)
1444 return PTR_ERR(key_ref
);
1446 /* viewing a key under construction is also permitted if we
1447 * have the authorisation token handy */
1448 instkey
= key_get_instantiation_authkey(keyid
);
1449 if (IS_ERR(instkey
))
1450 return PTR_ERR(instkey
);
1453 key_ref
= lookup_user_key(keyid
, KEY_LOOKUP_PARTIAL
, 0);
1454 if (IS_ERR(key_ref
))
1455 return PTR_ERR(key_ref
);
1458 key
= key_ref_to_ptr(key_ref
);
1459 ret
= security_key_getsecurity(key
, &context
);
1461 /* if no information was returned, give userspace an empty
1464 if (buffer
&& buflen
> 0 &&
1465 copy_to_user(buffer
, "", 1) != 0)
1467 } else if (ret
> 0) {
1468 /* return as much data as there's room for */
1469 if (buffer
&& buflen
> 0) {
1473 if (copy_to_user(buffer
, context
, buflen
) != 0)
1480 key_ref_put(key_ref
);
1485 * Attempt to install the calling process's session keyring on the process's
1488 * The keyring must exist and must grant the caller LINK permission, and the
1489 * parent process must be single-threaded and must have the same effective
1490 * ownership as this process and mustn't be SUID/SGID.
1492 * The keyring will be emplaced on the parent when it next resumes userspace.
1494 * If successful, 0 will be returned.
1496 long keyctl_session_to_parent(void)
1498 struct task_struct
*me
, *parent
;
1499 const struct cred
*mycred
, *pcred
;
1500 struct callback_head
*newwork
, *oldwork
;
1501 key_ref_t keyring_r
;
1505 keyring_r
= lookup_user_key(KEY_SPEC_SESSION_KEYRING
, 0, KEY_NEED_LINK
);
1506 if (IS_ERR(keyring_r
))
1507 return PTR_ERR(keyring_r
);
1511 /* our parent is going to need a new cred struct, a new tgcred struct
1512 * and new security data, so we allocate them here to prevent ENOMEM in
1514 cred
= cred_alloc_blank();
1517 newwork
= &cred
->rcu
;
1519 cred
->session_keyring
= key_ref_to_ptr(keyring_r
);
1521 init_task_work(newwork
, key_change_session_keyring
);
1525 write_lock_irq(&tasklist_lock
);
1529 parent
= me
->real_parent
;
1531 /* the parent mustn't be init and mustn't be a kernel thread */
1532 if (parent
->pid
<= 1 || !parent
->mm
)
1535 /* the parent must be single threaded */
1536 if (!thread_group_empty(parent
))
1539 /* the parent and the child must have different session keyrings or
1540 * there's no point */
1541 mycred
= current_cred();
1542 pcred
= __task_cred(parent
);
1543 if (mycred
== pcred
||
1544 mycred
->session_keyring
== pcred
->session_keyring
) {
1549 /* the parent must have the same effective ownership and mustn't be
1551 if (!uid_eq(pcred
->uid
, mycred
->euid
) ||
1552 !uid_eq(pcred
->euid
, mycred
->euid
) ||
1553 !uid_eq(pcred
->suid
, mycred
->euid
) ||
1554 !gid_eq(pcred
->gid
, mycred
->egid
) ||
1555 !gid_eq(pcred
->egid
, mycred
->egid
) ||
1556 !gid_eq(pcred
->sgid
, mycred
->egid
))
1559 /* the keyrings must have the same UID */
1560 if ((pcred
->session_keyring
&&
1561 !uid_eq(pcred
->session_keyring
->uid
, mycred
->euid
)) ||
1562 !uid_eq(mycred
->session_keyring
->uid
, mycred
->euid
))
1565 /* cancel an already pending keyring replacement */
1566 oldwork
= task_work_cancel(parent
, key_change_session_keyring
);
1568 /* the replacement session keyring is applied just prior to userspace
1570 ret
= task_work_add(parent
, newwork
, true);
1574 write_unlock_irq(&tasklist_lock
);
1577 put_cred(container_of(oldwork
, struct cred
, rcu
));
1583 key_ref_put(keyring_r
);
1588 * The key control system call
1590 SYSCALL_DEFINE5(keyctl
, int, option
, unsigned long, arg2
, unsigned long, arg3
,
1591 unsigned long, arg4
, unsigned long, arg5
)
1594 case KEYCTL_GET_KEYRING_ID
:
1595 return keyctl_get_keyring_ID((key_serial_t
) arg2
,
1598 case KEYCTL_JOIN_SESSION_KEYRING
:
1599 return keyctl_join_session_keyring((const char __user
*) arg2
);
1602 return keyctl_update_key((key_serial_t
) arg2
,
1603 (const void __user
*) arg3
,
1607 return keyctl_revoke_key((key_serial_t
) arg2
);
1609 case KEYCTL_DESCRIBE
:
1610 return keyctl_describe_key((key_serial_t
) arg2
,
1611 (char __user
*) arg3
,
1615 return keyctl_keyring_clear((key_serial_t
) arg2
);
1618 return keyctl_keyring_link((key_serial_t
) arg2
,
1619 (key_serial_t
) arg3
);
1622 return keyctl_keyring_unlink((key_serial_t
) arg2
,
1623 (key_serial_t
) arg3
);
1626 return keyctl_keyring_search((key_serial_t
) arg2
,
1627 (const char __user
*) arg3
,
1628 (const char __user
*) arg4
,
1629 (key_serial_t
) arg5
);
1632 return keyctl_read_key((key_serial_t
) arg2
,
1633 (char __user
*) arg3
,
1637 return keyctl_chown_key((key_serial_t
) arg2
,
1641 case KEYCTL_SETPERM
:
1642 return keyctl_setperm_key((key_serial_t
) arg2
,
1645 case KEYCTL_INSTANTIATE
:
1646 return keyctl_instantiate_key((key_serial_t
) arg2
,
1647 (const void __user
*) arg3
,
1649 (key_serial_t
) arg5
);
1652 return keyctl_negate_key((key_serial_t
) arg2
,
1654 (key_serial_t
) arg4
);
1656 case KEYCTL_SET_REQKEY_KEYRING
:
1657 return keyctl_set_reqkey_keyring(arg2
);
1659 case KEYCTL_SET_TIMEOUT
:
1660 return keyctl_set_timeout((key_serial_t
) arg2
,
1663 case KEYCTL_ASSUME_AUTHORITY
:
1664 return keyctl_assume_authority((key_serial_t
) arg2
);
1666 case KEYCTL_GET_SECURITY
:
1667 return keyctl_get_security((key_serial_t
) arg2
,
1668 (char __user
*) arg3
,
1671 case KEYCTL_SESSION_TO_PARENT
:
1672 return keyctl_session_to_parent();
1675 return keyctl_reject_key((key_serial_t
) arg2
,
1678 (key_serial_t
) arg5
);
1680 case KEYCTL_INSTANTIATE_IOV
:
1681 return keyctl_instantiate_key_iov(
1682 (key_serial_t
) arg2
,
1683 (const struct iovec __user
*) arg3
,
1685 (key_serial_t
) arg5
);
1687 case KEYCTL_INVALIDATE
:
1688 return keyctl_invalidate_key((key_serial_t
) arg2
);
1690 case KEYCTL_GET_PERSISTENT
:
1691 return keyctl_get_persistent((uid_t
)arg2
, (key_serial_t
)arg3
);
1693 case KEYCTL_DH_COMPUTE
:
1694 return keyctl_dh_compute((struct keyctl_dh_params __user
*) arg2
,
1695 (char __user
*) arg3
, (size_t) arg4
,
1696 (void __user
*) arg5
);