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>
29 #include <keys/request_key_auth-type.h>
32 #define KEY_MAX_DESC_SIZE 4096
34 static int key_get_type_from_user(char *type
,
35 const char __user
*_type
,
40 ret
= strncpy_from_user(type
, _type
, len
);
43 if (ret
== 0 || ret
>= len
)
52 * Extract the description of a new key from userspace and either add it as a
53 * new key to the specified keyring or update a matching key in that keyring.
55 * If the description is NULL or an empty string, the key type is asked to
56 * generate one from the payload.
58 * The keyring must be writable so that we can attach the key to it.
60 * If successful, the new key's serial number is returned, otherwise an error
63 SYSCALL_DEFINE5(add_key
, const char __user
*, _type
,
64 const char __user
*, _description
,
65 const void __user
*, _payload
,
69 key_ref_t keyring_ref
, key_ref
;
70 char type
[32], *description
;
75 if (plen
> 1024 * 1024 - 1)
78 /* draw all the data into kernel space */
79 ret
= key_get_type_from_user(type
, _type
, sizeof(type
));
85 description
= strndup_user(_description
, KEY_MAX_DESC_SIZE
);
86 if (IS_ERR(description
)) {
87 ret
= PTR_ERR(description
);
93 } else if ((description
[0] == '.') &&
94 (strncmp(type
, "keyring", 7) == 0)) {
100 /* pull the payload in if one was supplied */
105 payload
= kvmalloc(plen
, GFP_KERNEL
);
110 if (copy_from_user(payload
, _payload
, plen
) != 0)
114 /* find the target keyring (which must be writable) */
115 keyring_ref
= lookup_user_key(ringid
, KEY_LOOKUP_CREATE
, KEY_NEED_WRITE
);
116 if (IS_ERR(keyring_ref
)) {
117 ret
= PTR_ERR(keyring_ref
);
121 /* create or update the requested key and add it to the target
123 key_ref
= key_create_or_update(keyring_ref
, type
, description
,
124 payload
, plen
, KEY_PERM_UNDEF
,
126 if (!IS_ERR(key_ref
)) {
127 ret
= key_ref_to_ptr(key_ref
)->serial
;
128 key_ref_put(key_ref
);
131 ret
= PTR_ERR(key_ref
);
134 key_ref_put(keyring_ref
);
137 memzero_explicit(payload
, plen
);
147 * Search the process keyrings and keyring trees linked from those for a
148 * matching key. Keyrings must have appropriate Search permission to be
151 * If a key is found, it will be attached to the destination keyring if there's
152 * one specified and the serial number of the key will be returned.
154 * If no key is found, /sbin/request-key will be invoked if _callout_info is
155 * non-NULL in an attempt to create a key. The _callout_info string will be
156 * passed to /sbin/request-key to aid with completing the request. If the
157 * _callout_info string is "" then it will be changed to "-".
159 SYSCALL_DEFINE4(request_key
, const char __user
*, _type
,
160 const char __user
*, _description
,
161 const char __user
*, _callout_info
,
162 key_serial_t
, destringid
)
164 struct key_type
*ktype
;
168 char type
[32], *description
, *callout_info
;
171 /* pull the type into kernel space */
172 ret
= key_get_type_from_user(type
, _type
, sizeof(type
));
176 /* pull the description into kernel space */
177 description
= strndup_user(_description
, KEY_MAX_DESC_SIZE
);
178 if (IS_ERR(description
)) {
179 ret
= PTR_ERR(description
);
183 /* pull the callout info into kernel space */
187 callout_info
= strndup_user(_callout_info
, PAGE_SIZE
);
188 if (IS_ERR(callout_info
)) {
189 ret
= PTR_ERR(callout_info
);
192 callout_len
= strlen(callout_info
);
195 /* get the destination keyring if specified */
198 dest_ref
= lookup_user_key(destringid
, KEY_LOOKUP_CREATE
,
200 if (IS_ERR(dest_ref
)) {
201 ret
= PTR_ERR(dest_ref
);
206 /* find the key type */
207 ktype
= key_type_lookup(type
);
209 ret
= PTR_ERR(ktype
);
214 key
= request_key_and_link(ktype
, description
, callout_info
,
215 callout_len
, NULL
, key_ref_to_ptr(dest_ref
),
222 /* wait for the key to finish being constructed */
223 ret
= wait_for_key_construction(key
, 1);
234 key_ref_put(dest_ref
);
244 * Get the ID of the specified process keyring.
246 * The requested keyring must have search permission to be found.
248 * If successful, the ID of the requested keyring will be returned.
250 long keyctl_get_keyring_ID(key_serial_t id
, int create
)
253 unsigned long lflags
;
256 lflags
= create
? KEY_LOOKUP_CREATE
: 0;
257 key_ref
= lookup_user_key(id
, lflags
, KEY_NEED_SEARCH
);
258 if (IS_ERR(key_ref
)) {
259 ret
= PTR_ERR(key_ref
);
263 ret
= key_ref_to_ptr(key_ref
)->serial
;
264 key_ref_put(key_ref
);
270 * Join a (named) session keyring.
272 * Create and join an anonymous session keyring or join a named session
273 * keyring, creating it if necessary. A named session keyring must have Search
274 * permission for it to be joined. Session keyrings without this permit will
275 * be skipped over. It is not permitted for userspace to create or join
276 * keyrings whose name begin with a dot.
278 * If successful, the ID of the joined session keyring will be returned.
280 long keyctl_join_session_keyring(const char __user
*_name
)
285 /* fetch the name from userspace */
288 name
= strndup_user(_name
, KEY_MAX_DESC_SIZE
);
299 /* join the session */
300 ret
= join_session_keyring(name
);
308 * Update a key's data payload from the given data.
310 * The key must grant the caller Write permission and the key type must support
311 * updating for this to work. A negative key can be positively instantiated
314 * If successful, 0 will be returned. If the key type does not support
315 * updating, then -EOPNOTSUPP will be returned.
317 long keyctl_update_key(key_serial_t id
,
318 const void __user
*_payload
,
326 if (plen
> PAGE_SIZE
)
329 /* pull the payload in if one was supplied */
333 payload
= kmalloc(plen
, GFP_KERNEL
);
338 if (copy_from_user(payload
, _payload
, plen
) != 0)
342 /* find the target key (which must be writable) */
343 key_ref
= lookup_user_key(id
, 0, KEY_NEED_WRITE
);
344 if (IS_ERR(key_ref
)) {
345 ret
= PTR_ERR(key_ref
);
350 ret
= key_update(key_ref
, payload
, plen
);
352 key_ref_put(key_ref
);
362 * The key must be grant the caller Write or Setattr permission for this to
363 * work. The key type should give up its quota claim when revoked. The key
364 * and any links to the key will be automatically garbage collected after a
365 * certain amount of time (/proc/sys/kernel/keys/gc_delay).
367 * Keys with KEY_FLAG_KEEP set should not be revoked.
369 * If successful, 0 is returned.
371 long keyctl_revoke_key(key_serial_t id
)
377 key_ref
= lookup_user_key(id
, 0, KEY_NEED_WRITE
);
378 if (IS_ERR(key_ref
)) {
379 ret
= PTR_ERR(key_ref
);
382 key_ref
= lookup_user_key(id
, 0, KEY_NEED_SETATTR
);
383 if (IS_ERR(key_ref
)) {
384 ret
= PTR_ERR(key_ref
);
389 key
= key_ref_to_ptr(key_ref
);
391 if (test_bit(KEY_FLAG_KEEP
, &key
->flags
))
396 key_ref_put(key_ref
);
404 * The key must be grant the caller Invalidate permission for this to work.
405 * The key and any links to the key will be automatically garbage collected
408 * Keys with KEY_FLAG_KEEP set should not be invalidated.
410 * If successful, 0 is returned.
412 long keyctl_invalidate_key(key_serial_t id
)
420 key_ref
= lookup_user_key(id
, 0, KEY_NEED_SEARCH
);
421 if (IS_ERR(key_ref
)) {
422 ret
= PTR_ERR(key_ref
);
424 /* Root is permitted to invalidate certain special keys */
425 if (capable(CAP_SYS_ADMIN
)) {
426 key_ref
= lookup_user_key(id
, 0, 0);
429 if (test_bit(KEY_FLAG_ROOT_CAN_INVAL
,
430 &key_ref_to_ptr(key_ref
)->flags
))
439 key
= key_ref_to_ptr(key_ref
);
441 if (test_bit(KEY_FLAG_KEEP
, &key
->flags
))
446 key_ref_put(key_ref
);
448 kleave(" = %ld", ret
);
453 * Clear the specified keyring, creating an empty process keyring if one of the
454 * special keyring IDs is used.
456 * The keyring must grant the caller Write permission and not have
457 * KEY_FLAG_KEEP set for this to work. If successful, 0 will be returned.
459 long keyctl_keyring_clear(key_serial_t ringid
)
461 key_ref_t keyring_ref
;
465 keyring_ref
= lookup_user_key(ringid
, KEY_LOOKUP_CREATE
, KEY_NEED_WRITE
);
466 if (IS_ERR(keyring_ref
)) {
467 ret
= PTR_ERR(keyring_ref
);
469 /* Root is permitted to invalidate certain special keyrings */
470 if (capable(CAP_SYS_ADMIN
)) {
471 keyring_ref
= lookup_user_key(ringid
, 0, 0);
472 if (IS_ERR(keyring_ref
))
474 if (test_bit(KEY_FLAG_ROOT_CAN_CLEAR
,
475 &key_ref_to_ptr(keyring_ref
)->flags
))
484 keyring
= key_ref_to_ptr(keyring_ref
);
485 if (test_bit(KEY_FLAG_KEEP
, &keyring
->flags
))
488 ret
= keyring_clear(keyring
);
490 key_ref_put(keyring_ref
);
496 * Create a link from a keyring to a key if there's no matching key in the
497 * keyring, otherwise replace the link to the matching key with a link to the
500 * The key must grant the caller Link permission and the the keyring must grant
501 * the caller Write permission. Furthermore, if an additional link is created,
502 * the keyring's quota will be extended.
504 * If successful, 0 will be returned.
506 long keyctl_keyring_link(key_serial_t id
, key_serial_t ringid
)
508 key_ref_t keyring_ref
, key_ref
;
511 keyring_ref
= lookup_user_key(ringid
, KEY_LOOKUP_CREATE
, KEY_NEED_WRITE
);
512 if (IS_ERR(keyring_ref
)) {
513 ret
= PTR_ERR(keyring_ref
);
517 key_ref
= lookup_user_key(id
, KEY_LOOKUP_CREATE
, KEY_NEED_LINK
);
518 if (IS_ERR(key_ref
)) {
519 ret
= PTR_ERR(key_ref
);
523 ret
= key_link(key_ref_to_ptr(keyring_ref
), key_ref_to_ptr(key_ref
));
525 key_ref_put(key_ref
);
527 key_ref_put(keyring_ref
);
533 * Unlink a key from a keyring.
535 * The keyring must grant the caller Write permission for this to work; the key
536 * itself need not grant the caller anything. If the last link to a key is
537 * removed then that key will be scheduled for destruction.
539 * Keys or keyrings with KEY_FLAG_KEEP set should not be unlinked.
541 * If successful, 0 will be returned.
543 long keyctl_keyring_unlink(key_serial_t id
, key_serial_t ringid
)
545 key_ref_t keyring_ref
, key_ref
;
546 struct key
*keyring
, *key
;
549 keyring_ref
= lookup_user_key(ringid
, 0, KEY_NEED_WRITE
);
550 if (IS_ERR(keyring_ref
)) {
551 ret
= PTR_ERR(keyring_ref
);
555 key_ref
= lookup_user_key(id
, KEY_LOOKUP_FOR_UNLINK
, 0);
556 if (IS_ERR(key_ref
)) {
557 ret
= PTR_ERR(key_ref
);
561 keyring
= key_ref_to_ptr(keyring_ref
);
562 key
= key_ref_to_ptr(key_ref
);
563 if (test_bit(KEY_FLAG_KEEP
, &keyring
->flags
) &&
564 test_bit(KEY_FLAG_KEEP
, &key
->flags
))
567 ret
= key_unlink(keyring
, key
);
569 key_ref_put(key_ref
);
571 key_ref_put(keyring_ref
);
577 * Return a description of a key to userspace.
579 * The key must grant the caller View permission for this to work.
581 * If there's a buffer, we place up to buflen bytes of data into it formatted
582 * in the following way:
584 * type;uid;gid;perm;description<NUL>
586 * If successful, we return the amount of description available, irrespective
587 * of how much we may have copied into the buffer.
589 long keyctl_describe_key(key_serial_t keyid
,
593 struct key
*key
, *instkey
;
597 int desclen
, infolen
;
599 key_ref
= lookup_user_key(keyid
, KEY_LOOKUP_PARTIAL
, KEY_NEED_VIEW
);
600 if (IS_ERR(key_ref
)) {
601 /* viewing a key under construction is permitted if we have the
602 * authorisation token handy */
603 if (PTR_ERR(key_ref
) == -EACCES
) {
604 instkey
= key_get_instantiation_authkey(keyid
);
605 if (!IS_ERR(instkey
)) {
607 key_ref
= lookup_user_key(keyid
,
610 if (!IS_ERR(key_ref
))
615 ret
= PTR_ERR(key_ref
);
620 key
= key_ref_to_ptr(key_ref
);
621 desclen
= strlen(key
->description
);
623 /* calculate how much information we're going to return */
625 infobuf
= kasprintf(GFP_KERNEL
,
628 from_kuid_munged(current_user_ns(), key
->uid
),
629 from_kgid_munged(current_user_ns(), key
->gid
),
633 infolen
= strlen(infobuf
);
634 ret
= infolen
+ desclen
+ 1;
636 /* consider returning the data */
637 if (buffer
&& buflen
>= ret
) {
638 if (copy_to_user(buffer
, infobuf
, infolen
) != 0 ||
639 copy_to_user(buffer
+ infolen
, key
->description
,
646 key_ref_put(key_ref
);
652 * Search the specified keyring and any keyrings it links to for a matching
653 * key. Only keyrings that grant the caller Search permission will be searched
654 * (this includes the starting keyring). Only keys with Search permission can
657 * If successful, the found key will be linked to the destination keyring if
658 * supplied and the key has Link permission, and the found key ID will be
661 long keyctl_keyring_search(key_serial_t ringid
,
662 const char __user
*_type
,
663 const char __user
*_description
,
664 key_serial_t destringid
)
666 struct key_type
*ktype
;
667 key_ref_t keyring_ref
, key_ref
, dest_ref
;
668 char type
[32], *description
;
671 /* pull the type and description into kernel space */
672 ret
= key_get_type_from_user(type
, _type
, sizeof(type
));
676 description
= strndup_user(_description
, KEY_MAX_DESC_SIZE
);
677 if (IS_ERR(description
)) {
678 ret
= PTR_ERR(description
);
682 /* get the keyring at which to begin the search */
683 keyring_ref
= lookup_user_key(ringid
, 0, KEY_NEED_SEARCH
);
684 if (IS_ERR(keyring_ref
)) {
685 ret
= PTR_ERR(keyring_ref
);
689 /* get the destination keyring if specified */
692 dest_ref
= lookup_user_key(destringid
, KEY_LOOKUP_CREATE
,
694 if (IS_ERR(dest_ref
)) {
695 ret
= PTR_ERR(dest_ref
);
700 /* find the key type */
701 ktype
= key_type_lookup(type
);
703 ret
= PTR_ERR(ktype
);
708 key_ref
= keyring_search(keyring_ref
, ktype
, description
);
709 if (IS_ERR(key_ref
)) {
710 ret
= PTR_ERR(key_ref
);
712 /* treat lack or presence of a negative key the same */
718 /* link the resulting key to the destination keyring if we can */
720 ret
= key_permission(key_ref
, KEY_NEED_LINK
);
724 ret
= key_link(key_ref_to_ptr(dest_ref
), key_ref_to_ptr(key_ref
));
729 ret
= key_ref_to_ptr(key_ref
)->serial
;
732 key_ref_put(key_ref
);
736 key_ref_put(dest_ref
);
738 key_ref_put(keyring_ref
);
746 * Read a key's payload.
748 * The key must either grant the caller Read permission, or it must grant the
749 * caller Search permission when searched for from the process keyrings.
751 * If successful, we place up to buflen bytes of data into the buffer, if one
752 * is provided, and return the amount of data that is available in the key,
753 * irrespective of how much we copied into the buffer.
755 long keyctl_read_key(key_serial_t keyid
, char __user
*buffer
, size_t buflen
)
761 /* find the key first */
762 key_ref
= lookup_user_key(keyid
, 0, 0);
763 if (IS_ERR(key_ref
)) {
768 key
= key_ref_to_ptr(key_ref
);
770 ret
= key_read_state(key
);
772 goto error2
; /* Negatively instantiated */
774 /* see if we can read it directly */
775 ret
= key_permission(key_ref
, KEY_NEED_READ
);
781 /* we can't; see if it's searchable from this process's keyrings
782 * - we automatically take account of the fact that it may be
783 * dangling off an instantiation key
785 if (!is_key_possessed(key_ref
)) {
790 /* the key is probably readable - now try to read it */
793 if (key
->type
->read
) {
794 /* Read the data with the semaphore held (since we might sleep)
795 * to protect against the key being updated or revoked.
797 down_read(&key
->sem
);
798 ret
= key_validate(key
);
800 ret
= key
->type
->read(key
, buffer
, buflen
);
811 * Change the ownership of a key
813 * The key must grant the caller Setattr permission for this to work, though
814 * the key need not be fully instantiated yet. For the UID to be changed, or
815 * for the GID to be changed to a group the caller is not a member of, the
816 * caller must have sysadmin capability. If either uid or gid is -1 then that
817 * attribute is not changed.
819 * If the UID is to be changed, the new user must have sufficient quota to
820 * accept the key. The quota deduction will be removed from the old user to
821 * the new user should the attribute be changed.
823 * If successful, 0 will be returned.
825 long keyctl_chown_key(key_serial_t id
, uid_t user
, gid_t group
)
827 struct key_user
*newowner
, *zapowner
= NULL
;
834 uid
= make_kuid(current_user_ns(), user
);
835 gid
= make_kgid(current_user_ns(), group
);
837 if ((user
!= (uid_t
) -1) && !uid_valid(uid
))
839 if ((group
!= (gid_t
) -1) && !gid_valid(gid
))
843 if (user
== (uid_t
) -1 && group
== (gid_t
) -1)
846 key_ref
= lookup_user_key(id
, KEY_LOOKUP_CREATE
| KEY_LOOKUP_PARTIAL
,
848 if (IS_ERR(key_ref
)) {
849 ret
= PTR_ERR(key_ref
);
853 key
= key_ref_to_ptr(key_ref
);
855 /* make the changes with the locks held to prevent chown/chown races */
857 down_write(&key
->sem
);
859 if (!capable(CAP_SYS_ADMIN
)) {
860 /* only the sysadmin can chown a key to some other UID */
861 if (user
!= (uid_t
) -1 && !uid_eq(key
->uid
, uid
))
864 /* only the sysadmin can set the key's GID to a group other
865 * than one of those that the current process subscribes to */
866 if (group
!= (gid_t
) -1 && !gid_eq(gid
, key
->gid
) && !in_group_p(gid
))
871 if (user
!= (uid_t
) -1 && !uid_eq(uid
, key
->uid
)) {
873 newowner
= key_user_lookup(uid
);
877 /* transfer the quota burden to the new user */
878 if (test_bit(KEY_FLAG_IN_QUOTA
, &key
->flags
)) {
879 unsigned maxkeys
= uid_eq(uid
, GLOBAL_ROOT_UID
) ?
880 key_quota_root_maxkeys
: key_quota_maxkeys
;
881 unsigned maxbytes
= uid_eq(uid
, GLOBAL_ROOT_UID
) ?
882 key_quota_root_maxbytes
: key_quota_maxbytes
;
884 spin_lock(&newowner
->lock
);
885 if (newowner
->qnkeys
+ 1 >= maxkeys
||
886 newowner
->qnbytes
+ key
->quotalen
>= maxbytes
||
887 newowner
->qnbytes
+ key
->quotalen
<
892 newowner
->qnbytes
+= key
->quotalen
;
893 spin_unlock(&newowner
->lock
);
895 spin_lock(&key
->user
->lock
);
897 key
->user
->qnbytes
-= key
->quotalen
;
898 spin_unlock(&key
->user
->lock
);
901 atomic_dec(&key
->user
->nkeys
);
902 atomic_inc(&newowner
->nkeys
);
904 if (key
->state
!= KEY_IS_UNINSTANTIATED
) {
905 atomic_dec(&key
->user
->nikeys
);
906 atomic_inc(&newowner
->nikeys
);
909 zapowner
= key
->user
;
910 key
->user
= newowner
;
915 if (group
!= (gid_t
) -1)
924 key_user_put(zapowner
);
929 spin_unlock(&newowner
->lock
);
936 * Change the permission mask on a key.
938 * The key must grant the caller Setattr permission for this to work, though
939 * the key need not be fully instantiated yet. If the caller does not have
940 * sysadmin capability, it may only change the permission on keys that it owns.
942 long keyctl_setperm_key(key_serial_t id
, key_perm_t perm
)
949 if (perm
& ~(KEY_POS_ALL
| KEY_USR_ALL
| KEY_GRP_ALL
| KEY_OTH_ALL
))
952 key_ref
= lookup_user_key(id
, KEY_LOOKUP_CREATE
| KEY_LOOKUP_PARTIAL
,
954 if (IS_ERR(key_ref
)) {
955 ret
= PTR_ERR(key_ref
);
959 key
= key_ref_to_ptr(key_ref
);
961 /* make the changes with the locks held to prevent chown/chmod races */
963 down_write(&key
->sem
);
965 /* if we're not the sysadmin, we can only change a key that we own */
966 if (capable(CAP_SYS_ADMIN
) || uid_eq(key
->uid
, current_fsuid())) {
978 * Get the destination keyring for instantiation and check that the caller has
979 * Write permission on it.
981 static long get_instantiation_keyring(key_serial_t ringid
,
982 struct request_key_auth
*rka
,
983 struct key
**_dest_keyring
)
987 *_dest_keyring
= NULL
;
989 /* just return a NULL pointer if we weren't asked to make a link */
993 /* if a specific keyring is nominated by ID, then use that */
995 dkref
= lookup_user_key(ringid
, KEY_LOOKUP_CREATE
, KEY_NEED_WRITE
);
997 return PTR_ERR(dkref
);
998 *_dest_keyring
= key_ref_to_ptr(dkref
);
1002 if (ringid
== KEY_SPEC_REQKEY_AUTH_KEY
)
1005 /* otherwise specify the destination keyring recorded in the
1006 * authorisation key (any KEY_SPEC_*_KEYRING) */
1007 if (ringid
>= KEY_SPEC_REQUESTOR_KEYRING
) {
1008 *_dest_keyring
= key_get(rka
->dest_keyring
);
1016 * Change the request_key authorisation key on the current process.
1018 static int keyctl_change_reqkey_auth(struct key
*key
)
1022 new = prepare_creds();
1026 key_put(new->request_key_auth
);
1027 new->request_key_auth
= key_get(key
);
1029 return commit_creds(new);
1033 * Instantiate a key with the specified payload and link the key into the
1034 * destination keyring if one is given.
1036 * The caller must have the appropriate instantiation permit set for this to
1037 * work (see keyctl_assume_authority). No other permissions are required.
1039 * If successful, 0 will be returned.
1041 long keyctl_instantiate_key_common(key_serial_t id
,
1042 struct iov_iter
*from
,
1043 key_serial_t ringid
)
1045 const struct cred
*cred
= current_cred();
1046 struct request_key_auth
*rka
;
1047 struct key
*instkey
, *dest_keyring
;
1048 size_t plen
= from
? iov_iter_count(from
) : 0;
1052 kenter("%d,,%zu,%d", id
, plen
, ringid
);
1058 if (plen
> 1024 * 1024 - 1)
1061 /* the appropriate instantiation authorisation key must have been
1062 * assumed before calling this */
1064 instkey
= cred
->request_key_auth
;
1068 rka
= instkey
->payload
.data
[0];
1069 if (rka
->target_key
->serial
!= id
)
1072 /* pull the payload in if one was supplied */
1077 payload
= kvmalloc(plen
, GFP_KERNEL
);
1082 if (!copy_from_iter_full(payload
, plen
, from
))
1086 /* find the destination keyring amongst those belonging to the
1087 * requesting task */
1088 ret
= get_instantiation_keyring(ringid
, rka
, &dest_keyring
);
1092 /* instantiate the key and link it into a keyring */
1093 ret
= key_instantiate_and_link(rka
->target_key
, payload
, plen
,
1094 dest_keyring
, instkey
);
1096 key_put(dest_keyring
);
1098 /* discard the assumed authority if it's just been disabled by
1099 * instantiation of the key */
1101 keyctl_change_reqkey_auth(NULL
);
1105 memzero_explicit(payload
, plen
);
1113 * Instantiate a key with the specified payload and link the key into the
1114 * destination keyring if one is given.
1116 * The caller must have the appropriate instantiation permit set for this to
1117 * work (see keyctl_assume_authority). No other permissions are required.
1119 * If successful, 0 will be returned.
1121 long keyctl_instantiate_key(key_serial_t id
,
1122 const void __user
*_payload
,
1124 key_serial_t ringid
)
1126 if (_payload
&& plen
) {
1128 struct iov_iter from
;
1131 ret
= import_single_range(WRITE
, (void __user
*)_payload
, plen
,
1136 return keyctl_instantiate_key_common(id
, &from
, ringid
);
1139 return keyctl_instantiate_key_common(id
, NULL
, ringid
);
1143 * Instantiate a key with the specified multipart payload and link the key into
1144 * the destination keyring if one is given.
1146 * The caller must have the appropriate instantiation permit set for this to
1147 * work (see keyctl_assume_authority). No other permissions are required.
1149 * If successful, 0 will be returned.
1151 long keyctl_instantiate_key_iov(key_serial_t id
,
1152 const struct iovec __user
*_payload_iov
,
1154 key_serial_t ringid
)
1156 struct iovec iovstack
[UIO_FASTIOV
], *iov
= iovstack
;
1157 struct iov_iter from
;
1163 ret
= import_iovec(WRITE
, _payload_iov
, ioc
,
1164 ARRAY_SIZE(iovstack
), &iov
, &from
);
1167 ret
= keyctl_instantiate_key_common(id
, &from
, ringid
);
1173 * Negatively instantiate the key with the given timeout (in seconds) and link
1174 * the key into the destination keyring if one is given.
1176 * The caller must have the appropriate instantiation permit set for this to
1177 * work (see keyctl_assume_authority). No other permissions are required.
1179 * The key and any links to the key will be automatically garbage collected
1180 * after the timeout expires.
1182 * Negative keys are used to rate limit repeated request_key() calls by causing
1183 * them to return -ENOKEY until the negative key expires.
1185 * If successful, 0 will be returned.
1187 long keyctl_negate_key(key_serial_t id
, unsigned timeout
, key_serial_t ringid
)
1189 return keyctl_reject_key(id
, timeout
, ENOKEY
, ringid
);
1193 * Negatively instantiate the key with the given timeout (in seconds) and error
1194 * code and link the key into the destination keyring if one is given.
1196 * The caller must have the appropriate instantiation permit set for this to
1197 * work (see keyctl_assume_authority). No other permissions are required.
1199 * The key and any links to the key will be automatically garbage collected
1200 * after the timeout expires.
1202 * Negative keys are used to rate limit repeated request_key() calls by causing
1203 * them to return the specified error code until the negative key expires.
1205 * If successful, 0 will be returned.
1207 long keyctl_reject_key(key_serial_t id
, unsigned timeout
, unsigned error
,
1208 key_serial_t ringid
)
1210 const struct cred
*cred
= current_cred();
1211 struct request_key_auth
*rka
;
1212 struct key
*instkey
, *dest_keyring
;
1215 kenter("%d,%u,%u,%d", id
, timeout
, error
, ringid
);
1217 /* must be a valid error code and mustn't be a kernel special */
1219 error
>= MAX_ERRNO
||
1220 error
== ERESTARTSYS
||
1221 error
== ERESTARTNOINTR
||
1222 error
== ERESTARTNOHAND
||
1223 error
== ERESTART_RESTARTBLOCK
)
1226 /* the appropriate instantiation authorisation key must have been
1227 * assumed before calling this */
1229 instkey
= cred
->request_key_auth
;
1233 rka
= instkey
->payload
.data
[0];
1234 if (rka
->target_key
->serial
!= id
)
1237 /* find the destination keyring if present (which must also be
1239 ret
= get_instantiation_keyring(ringid
, rka
, &dest_keyring
);
1243 /* instantiate the key and link it into a keyring */
1244 ret
= key_reject_and_link(rka
->target_key
, timeout
, error
,
1245 dest_keyring
, instkey
);
1247 key_put(dest_keyring
);
1249 /* discard the assumed authority if it's just been disabled by
1250 * instantiation of the key */
1252 keyctl_change_reqkey_auth(NULL
);
1259 * Read or set the default keyring in which request_key() will cache keys and
1260 * return the old setting.
1262 * If a thread or process keyring is specified then it will be created if it
1263 * doesn't yet exist. The old setting will be returned if successful.
1265 long keyctl_set_reqkey_keyring(int reqkey_defl
)
1268 int ret
, old_setting
;
1270 old_setting
= current_cred_xxx(jit_keyring
);
1272 if (reqkey_defl
== KEY_REQKEY_DEFL_NO_CHANGE
)
1275 new = prepare_creds();
1279 switch (reqkey_defl
) {
1280 case KEY_REQKEY_DEFL_THREAD_KEYRING
:
1281 ret
= install_thread_keyring_to_cred(new);
1286 case KEY_REQKEY_DEFL_PROCESS_KEYRING
:
1287 ret
= install_process_keyring_to_cred(new);
1292 case KEY_REQKEY_DEFL_DEFAULT
:
1293 case KEY_REQKEY_DEFL_SESSION_KEYRING
:
1294 case KEY_REQKEY_DEFL_USER_KEYRING
:
1295 case KEY_REQKEY_DEFL_USER_SESSION_KEYRING
:
1296 case KEY_REQKEY_DEFL_REQUESTOR_KEYRING
:
1299 case KEY_REQKEY_DEFL_NO_CHANGE
:
1300 case KEY_REQKEY_DEFL_GROUP_KEYRING
:
1307 new->jit_keyring
= reqkey_defl
;
1316 * Set or clear the timeout on a key.
1318 * Either the key must grant the caller Setattr permission or else the caller
1319 * must hold an instantiation authorisation token for the key.
1321 * The timeout is either 0 to clear the timeout, or a number of seconds from
1322 * the current time. The key and any links to the key will be automatically
1323 * garbage collected after the timeout expires.
1325 * Keys with KEY_FLAG_KEEP set should not be timed out.
1327 * If successful, 0 is returned.
1329 long keyctl_set_timeout(key_serial_t id
, unsigned timeout
)
1331 struct key
*key
, *instkey
;
1335 key_ref
= lookup_user_key(id
, KEY_LOOKUP_CREATE
| KEY_LOOKUP_PARTIAL
,
1337 if (IS_ERR(key_ref
)) {
1338 /* setting the timeout on a key under construction is permitted
1339 * if we have the authorisation token handy */
1340 if (PTR_ERR(key_ref
) == -EACCES
) {
1341 instkey
= key_get_instantiation_authkey(id
);
1342 if (!IS_ERR(instkey
)) {
1344 key_ref
= lookup_user_key(id
,
1347 if (!IS_ERR(key_ref
))
1352 ret
= PTR_ERR(key_ref
);
1357 key
= key_ref_to_ptr(key_ref
);
1359 if (test_bit(KEY_FLAG_KEEP
, &key
->flags
))
1362 key_set_timeout(key
, timeout
);
1370 * Assume (or clear) the authority to instantiate the specified key.
1372 * This sets the authoritative token currently in force for key instantiation.
1373 * This must be done for a key to be instantiated. It has the effect of making
1374 * available all the keys from the caller of the request_key() that created a
1375 * key to request_key() calls made by the caller of this function.
1377 * The caller must have the instantiation key in their process keyrings with a
1378 * Search permission grant available to the caller.
1380 * If the ID given is 0, then the setting will be cleared and 0 returned.
1382 * If the ID given has a matching an authorisation key, then that key will be
1383 * set and its ID will be returned. The authorisation key can be read to get
1384 * the callout information passed to request_key().
1386 long keyctl_assume_authority(key_serial_t id
)
1388 struct key
*authkey
;
1391 /* special key IDs aren't permitted */
1396 /* we divest ourselves of authority if given an ID of 0 */
1398 ret
= keyctl_change_reqkey_auth(NULL
);
1402 /* attempt to assume the authority temporarily granted to us whilst we
1403 * instantiate the specified key
1404 * - the authorisation key must be in the current task's keyrings
1407 authkey
= key_get_instantiation_authkey(id
);
1408 if (IS_ERR(authkey
)) {
1409 ret
= PTR_ERR(authkey
);
1413 ret
= keyctl_change_reqkey_auth(authkey
);
1415 ret
= authkey
->serial
;
1422 * Get a key's the LSM security label.
1424 * The key must grant the caller View permission for this to work.
1426 * If there's a buffer, then up to buflen bytes of data will be placed into it.
1428 * If successful, the amount of information available will be returned,
1429 * irrespective of how much was copied (including the terminal NUL).
1431 long keyctl_get_security(key_serial_t keyid
,
1432 char __user
*buffer
,
1435 struct key
*key
, *instkey
;
1440 key_ref
= lookup_user_key(keyid
, KEY_LOOKUP_PARTIAL
, KEY_NEED_VIEW
);
1441 if (IS_ERR(key_ref
)) {
1442 if (PTR_ERR(key_ref
) != -EACCES
)
1443 return PTR_ERR(key_ref
);
1445 /* viewing a key under construction is also permitted if we
1446 * have the authorisation token handy */
1447 instkey
= key_get_instantiation_authkey(keyid
);
1448 if (IS_ERR(instkey
))
1449 return PTR_ERR(instkey
);
1452 key_ref
= lookup_user_key(keyid
, KEY_LOOKUP_PARTIAL
, 0);
1453 if (IS_ERR(key_ref
))
1454 return PTR_ERR(key_ref
);
1457 key
= key_ref_to_ptr(key_ref
);
1458 ret
= security_key_getsecurity(key
, &context
);
1460 /* if no information was returned, give userspace an empty
1463 if (buffer
&& buflen
> 0 &&
1464 copy_to_user(buffer
, "", 1) != 0)
1466 } else if (ret
> 0) {
1467 /* return as much data as there's room for */
1468 if (buffer
&& buflen
> 0) {
1472 if (copy_to_user(buffer
, context
, buflen
) != 0)
1479 key_ref_put(key_ref
);
1484 * Attempt to install the calling process's session keyring on the process's
1487 * The keyring must exist and must grant the caller LINK permission, and the
1488 * parent process must be single-threaded and must have the same effective
1489 * ownership as this process and mustn't be SUID/SGID.
1491 * The keyring will be emplaced on the parent when it next resumes userspace.
1493 * If successful, 0 will be returned.
1495 long keyctl_session_to_parent(void)
1497 struct task_struct
*me
, *parent
;
1498 const struct cred
*mycred
, *pcred
;
1499 struct callback_head
*newwork
, *oldwork
;
1500 key_ref_t keyring_r
;
1504 keyring_r
= lookup_user_key(KEY_SPEC_SESSION_KEYRING
, 0, KEY_NEED_LINK
);
1505 if (IS_ERR(keyring_r
))
1506 return PTR_ERR(keyring_r
);
1510 /* our parent is going to need a new cred struct, a new tgcred struct
1511 * and new security data, so we allocate them here to prevent ENOMEM in
1513 cred
= cred_alloc_blank();
1516 newwork
= &cred
->rcu
;
1518 cred
->session_keyring
= key_ref_to_ptr(keyring_r
);
1520 init_task_work(newwork
, key_change_session_keyring
);
1524 write_lock_irq(&tasklist_lock
);
1528 parent
= me
->real_parent
;
1530 /* the parent mustn't be init and mustn't be a kernel thread */
1531 if (parent
->pid
<= 1 || !parent
->mm
)
1534 /* the parent must be single threaded */
1535 if (!thread_group_empty(parent
))
1538 /* the parent and the child must have different session keyrings or
1539 * there's no point */
1540 mycred
= current_cred();
1541 pcred
= __task_cred(parent
);
1542 if (mycred
== pcred
||
1543 mycred
->session_keyring
== pcred
->session_keyring
) {
1548 /* the parent must have the same effective ownership and mustn't be
1550 if (!uid_eq(pcred
->uid
, mycred
->euid
) ||
1551 !uid_eq(pcred
->euid
, mycred
->euid
) ||
1552 !uid_eq(pcred
->suid
, mycred
->euid
) ||
1553 !gid_eq(pcred
->gid
, mycred
->egid
) ||
1554 !gid_eq(pcred
->egid
, mycred
->egid
) ||
1555 !gid_eq(pcred
->sgid
, mycred
->egid
))
1558 /* the keyrings must have the same UID */
1559 if ((pcred
->session_keyring
&&
1560 !uid_eq(pcred
->session_keyring
->uid
, mycred
->euid
)) ||
1561 !uid_eq(mycred
->session_keyring
->uid
, mycred
->euid
))
1564 /* cancel an already pending keyring replacement */
1565 oldwork
= task_work_cancel(parent
, key_change_session_keyring
);
1567 /* the replacement session keyring is applied just prior to userspace
1569 ret
= task_work_add(parent
, newwork
, true);
1573 write_unlock_irq(&tasklist_lock
);
1576 put_cred(container_of(oldwork
, struct cred
, rcu
));
1582 key_ref_put(keyring_r
);
1587 * Apply a restriction to a given keyring.
1589 * The caller must have Setattr permission to change keyring restrictions.
1591 * The requested type name may be a NULL pointer to reject all attempts
1592 * to link to the keyring. In this case, _restriction must also be NULL.
1593 * Otherwise, both _type and _restriction must be non-NULL.
1595 * Returns 0 if successful.
1597 long keyctl_restrict_keyring(key_serial_t id
, const char __user
*_type
,
1598 const char __user
*_restriction
)
1602 char *restriction
= NULL
;
1605 key_ref
= lookup_user_key(id
, 0, KEY_NEED_SETATTR
);
1606 if (IS_ERR(key_ref
))
1607 return PTR_ERR(key_ref
);
1614 ret
= key_get_type_from_user(type
, _type
, sizeof(type
));
1618 restriction
= strndup_user(_restriction
, PAGE_SIZE
);
1619 if (IS_ERR(restriction
)) {
1620 ret
= PTR_ERR(restriction
);
1628 ret
= keyring_restrict(key_ref
, _type
? type
: NULL
, restriction
);
1631 key_ref_put(key_ref
);
1636 * The key control system call
1638 SYSCALL_DEFINE5(keyctl
, int, option
, unsigned long, arg2
, unsigned long, arg3
,
1639 unsigned long, arg4
, unsigned long, arg5
)
1642 case KEYCTL_GET_KEYRING_ID
:
1643 return keyctl_get_keyring_ID((key_serial_t
) arg2
,
1646 case KEYCTL_JOIN_SESSION_KEYRING
:
1647 return keyctl_join_session_keyring((const char __user
*) arg2
);
1650 return keyctl_update_key((key_serial_t
) arg2
,
1651 (const void __user
*) arg3
,
1655 return keyctl_revoke_key((key_serial_t
) arg2
);
1657 case KEYCTL_DESCRIBE
:
1658 return keyctl_describe_key((key_serial_t
) arg2
,
1659 (char __user
*) arg3
,
1663 return keyctl_keyring_clear((key_serial_t
) arg2
);
1666 return keyctl_keyring_link((key_serial_t
) arg2
,
1667 (key_serial_t
) arg3
);
1670 return keyctl_keyring_unlink((key_serial_t
) arg2
,
1671 (key_serial_t
) arg3
);
1674 return keyctl_keyring_search((key_serial_t
) arg2
,
1675 (const char __user
*) arg3
,
1676 (const char __user
*) arg4
,
1677 (key_serial_t
) arg5
);
1680 return keyctl_read_key((key_serial_t
) arg2
,
1681 (char __user
*) arg3
,
1685 return keyctl_chown_key((key_serial_t
) arg2
,
1689 case KEYCTL_SETPERM
:
1690 return keyctl_setperm_key((key_serial_t
) arg2
,
1693 case KEYCTL_INSTANTIATE
:
1694 return keyctl_instantiate_key((key_serial_t
) arg2
,
1695 (const void __user
*) arg3
,
1697 (key_serial_t
) arg5
);
1700 return keyctl_negate_key((key_serial_t
) arg2
,
1702 (key_serial_t
) arg4
);
1704 case KEYCTL_SET_REQKEY_KEYRING
:
1705 return keyctl_set_reqkey_keyring(arg2
);
1707 case KEYCTL_SET_TIMEOUT
:
1708 return keyctl_set_timeout((key_serial_t
) arg2
,
1711 case KEYCTL_ASSUME_AUTHORITY
:
1712 return keyctl_assume_authority((key_serial_t
) arg2
);
1714 case KEYCTL_GET_SECURITY
:
1715 return keyctl_get_security((key_serial_t
) arg2
,
1716 (char __user
*) arg3
,
1719 case KEYCTL_SESSION_TO_PARENT
:
1720 return keyctl_session_to_parent();
1723 return keyctl_reject_key((key_serial_t
) arg2
,
1726 (key_serial_t
) arg5
);
1728 case KEYCTL_INSTANTIATE_IOV
:
1729 return keyctl_instantiate_key_iov(
1730 (key_serial_t
) arg2
,
1731 (const struct iovec __user
*) arg3
,
1733 (key_serial_t
) arg5
);
1735 case KEYCTL_INVALIDATE
:
1736 return keyctl_invalidate_key((key_serial_t
) arg2
);
1738 case KEYCTL_GET_PERSISTENT
:
1739 return keyctl_get_persistent((uid_t
)arg2
, (key_serial_t
)arg3
);
1741 case KEYCTL_DH_COMPUTE
:
1742 return keyctl_dh_compute((struct keyctl_dh_params __user
*) arg2
,
1743 (char __user
*) arg3
, (size_t) arg4
,
1744 (struct keyctl_kdf_params __user
*) arg5
);
1746 case KEYCTL_RESTRICT_KEYRING
:
1747 return keyctl_restrict_keyring((key_serial_t
) arg2
,
1748 (const char __user
*) arg3
,
1749 (const char __user
*) arg4
);