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 = kvmalloc(plen, GFP_KERNEL);
109 if (copy_from_user(payload, _payload, plen) != 0)
113 /* find the target keyring (which must be writable) */
114 keyring_ref = lookup_user_key(ringid, KEY_LOOKUP_CREATE, KEY_NEED_WRITE);
115 if (IS_ERR(keyring_ref)) {
116 ret = PTR_ERR(keyring_ref);
120 /* create or update the requested key and add it to the target
122 key_ref = key_create_or_update(keyring_ref, type, description,
123 payload, plen, KEY_PERM_UNDEF,
125 if (!IS_ERR(key_ref)) {
126 ret = key_ref_to_ptr(key_ref)->serial;
127 key_ref_put(key_ref);
130 ret = PTR_ERR(key_ref);
133 key_ref_put(keyring_ref);
143 * Search the process keyrings and keyring trees linked from those for a
144 * matching key. Keyrings must have appropriate Search permission to be
147 * If a key is found, it will be attached to the destination keyring if there's
148 * one specified and the serial number of the key will be returned.
150 * If no key is found, /sbin/request-key will be invoked if _callout_info is
151 * non-NULL in an attempt to create a key. The _callout_info string will be
152 * passed to /sbin/request-key to aid with completing the request. If the
153 * _callout_info string is "" then it will be changed to "-".
155 SYSCALL_DEFINE4(request_key, const char __user *, _type,
156 const char __user *, _description,
157 const char __user *, _callout_info,
158 key_serial_t, destringid)
160 struct key_type *ktype;
164 char type[32], *description, *callout_info;
167 /* pull the type into kernel space */
168 ret = key_get_type_from_user(type, _type, sizeof(type));
172 /* pull the description into kernel space */
173 description = strndup_user(_description, KEY_MAX_DESC_SIZE);
174 if (IS_ERR(description)) {
175 ret = PTR_ERR(description);
179 /* pull the callout info into kernel space */
183 callout_info = strndup_user(_callout_info, PAGE_SIZE);
184 if (IS_ERR(callout_info)) {
185 ret = PTR_ERR(callout_info);
188 callout_len = strlen(callout_info);
191 /* get the destination keyring if specified */
194 dest_ref = lookup_user_key(destringid, KEY_LOOKUP_CREATE,
196 if (IS_ERR(dest_ref)) {
197 ret = PTR_ERR(dest_ref);
202 /* find the key type */
203 ktype = key_type_lookup(type);
205 ret = PTR_ERR(ktype);
210 key = request_key_and_link(ktype, description, callout_info,
211 callout_len, NULL, key_ref_to_ptr(dest_ref),
218 /* wait for the key to finish being constructed */
219 ret = wait_for_key_construction(key, 1);
230 key_ref_put(dest_ref);
240 * Get the ID of the specified process keyring.
242 * The requested keyring must have search permission to be found.
244 * If successful, the ID of the requested keyring will be returned.
246 long keyctl_get_keyring_ID(key_serial_t id, int create)
249 unsigned long lflags;
252 lflags = create ? KEY_LOOKUP_CREATE : 0;
253 key_ref = lookup_user_key(id, lflags, KEY_NEED_SEARCH);
254 if (IS_ERR(key_ref)) {
255 ret = PTR_ERR(key_ref);
259 ret = key_ref_to_ptr(key_ref)->serial;
260 key_ref_put(key_ref);
266 * Join a (named) session keyring.
268 * Create and join an anonymous session keyring or join a named session
269 * keyring, creating it if necessary. A named session keyring must have Search
270 * permission for it to be joined. Session keyrings without this permit will
271 * be skipped over. It is not permitted for userspace to create or join
272 * keyrings whose name begin with a dot.
274 * If successful, the ID of the joined session keyring will be returned.
276 long keyctl_join_session_keyring(const char __user *_name)
281 /* fetch the name from userspace */
284 name = strndup_user(_name, KEY_MAX_DESC_SIZE);
295 /* join the session */
296 ret = join_session_keyring(name);
304 * Update a key's data payload from the given data.
306 * The key must grant the caller Write permission and the key type must support
307 * updating for this to work. A negative key can be positively instantiated
310 * If successful, 0 will be returned. If the key type does not support
311 * updating, then -EOPNOTSUPP will be returned.
313 long keyctl_update_key(key_serial_t id,
314 const void __user *_payload,
322 if (plen > PAGE_SIZE)
325 /* pull the payload in if one was supplied */
329 payload = kmalloc(plen, GFP_KERNEL);
334 if (copy_from_user(payload, _payload, plen) != 0)
338 /* find the target key (which must be writable) */
339 key_ref = lookup_user_key(id, 0, KEY_NEED_WRITE);
340 if (IS_ERR(key_ref)) {
341 ret = PTR_ERR(key_ref);
346 ret = key_update(key_ref, payload, plen);
348 key_ref_put(key_ref);
358 * The key must be grant the caller Write or Setattr permission for this to
359 * work. The key type should give up its quota claim when revoked. The key
360 * and any links to the key will be automatically garbage collected after a
361 * certain amount of time (/proc/sys/kernel/keys/gc_delay).
363 * Keys with KEY_FLAG_KEEP set should not be revoked.
365 * If successful, 0 is returned.
367 long keyctl_revoke_key(key_serial_t id)
373 key_ref = lookup_user_key(id, 0, KEY_NEED_WRITE);
374 if (IS_ERR(key_ref)) {
375 ret = PTR_ERR(key_ref);
378 key_ref = lookup_user_key(id, 0, KEY_NEED_SETATTR);
379 if (IS_ERR(key_ref)) {
380 ret = PTR_ERR(key_ref);
385 key = key_ref_to_ptr(key_ref);
387 if (test_bit(KEY_FLAG_KEEP, &key->flags))
392 key_ref_put(key_ref);
400 * The key must be grant the caller Invalidate permission for this to work.
401 * The key and any links to the key will be automatically garbage collected
404 * Keys with KEY_FLAG_KEEP set should not be invalidated.
406 * If successful, 0 is returned.
408 long keyctl_invalidate_key(key_serial_t id)
416 key_ref = lookup_user_key(id, 0, KEY_NEED_SEARCH);
417 if (IS_ERR(key_ref)) {
418 ret = PTR_ERR(key_ref);
420 /* Root is permitted to invalidate certain special keys */
421 if (capable(CAP_SYS_ADMIN)) {
422 key_ref = lookup_user_key(id, 0, 0);
425 if (test_bit(KEY_FLAG_ROOT_CAN_INVAL,
426 &key_ref_to_ptr(key_ref)->flags))
435 key = key_ref_to_ptr(key_ref);
437 if (test_bit(KEY_FLAG_KEEP, &key->flags))
442 key_ref_put(key_ref);
444 kleave(" = %ld", ret);
449 * Clear the specified keyring, creating an empty process keyring if one of the
450 * special keyring IDs is used.
452 * The keyring must grant the caller Write permission and not have
453 * KEY_FLAG_KEEP set for this to work. If successful, 0 will be returned.
455 long keyctl_keyring_clear(key_serial_t ringid)
457 key_ref_t keyring_ref;
461 keyring_ref = lookup_user_key(ringid, KEY_LOOKUP_CREATE, KEY_NEED_WRITE);
462 if (IS_ERR(keyring_ref)) {
463 ret = PTR_ERR(keyring_ref);
465 /* Root is permitted to invalidate certain special keyrings */
466 if (capable(CAP_SYS_ADMIN)) {
467 keyring_ref = lookup_user_key(ringid, 0, 0);
468 if (IS_ERR(keyring_ref))
470 if (test_bit(KEY_FLAG_ROOT_CAN_CLEAR,
471 &key_ref_to_ptr(keyring_ref)->flags))
480 keyring = key_ref_to_ptr(keyring_ref);
481 if (test_bit(KEY_FLAG_KEEP, &keyring->flags))
484 ret = keyring_clear(keyring);
486 key_ref_put(keyring_ref);
492 * Create a link from a keyring to a key if there's no matching key in the
493 * keyring, otherwise replace the link to the matching key with a link to the
496 * The key must grant the caller Link permission and the the keyring must grant
497 * the caller Write permission. Furthermore, if an additional link is created,
498 * the keyring's quota will be extended.
500 * If successful, 0 will be returned.
502 long keyctl_keyring_link(key_serial_t id, key_serial_t ringid)
504 key_ref_t keyring_ref, key_ref;
507 keyring_ref = lookup_user_key(ringid, KEY_LOOKUP_CREATE, KEY_NEED_WRITE);
508 if (IS_ERR(keyring_ref)) {
509 ret = PTR_ERR(keyring_ref);
513 key_ref = lookup_user_key(id, KEY_LOOKUP_CREATE, KEY_NEED_LINK);
514 if (IS_ERR(key_ref)) {
515 ret = PTR_ERR(key_ref);
519 ret = key_link(key_ref_to_ptr(keyring_ref), key_ref_to_ptr(key_ref));
521 key_ref_put(key_ref);
523 key_ref_put(keyring_ref);
529 * Unlink a key from a keyring.
531 * The keyring must grant the caller Write permission for this to work; the key
532 * itself need not grant the caller anything. If the last link to a key is
533 * removed then that key will be scheduled for destruction.
535 * Keys or keyrings with KEY_FLAG_KEEP set should not be unlinked.
537 * If successful, 0 will be returned.
539 long keyctl_keyring_unlink(key_serial_t id, key_serial_t ringid)
541 key_ref_t keyring_ref, key_ref;
542 struct key *keyring, *key;
545 keyring_ref = lookup_user_key(ringid, 0, KEY_NEED_WRITE);
546 if (IS_ERR(keyring_ref)) {
547 ret = PTR_ERR(keyring_ref);
551 key_ref = lookup_user_key(id, KEY_LOOKUP_FOR_UNLINK, 0);
552 if (IS_ERR(key_ref)) {
553 ret = PTR_ERR(key_ref);
557 keyring = key_ref_to_ptr(keyring_ref);
558 key = key_ref_to_ptr(key_ref);
559 if (test_bit(KEY_FLAG_KEEP, &keyring->flags) &&
560 test_bit(KEY_FLAG_KEEP, &key->flags))
563 ret = key_unlink(keyring, key);
565 key_ref_put(key_ref);
567 key_ref_put(keyring_ref);
573 * Return a description of a key to userspace.
575 * The key must grant the caller View permission for this to work.
577 * If there's a buffer, we place up to buflen bytes of data into it formatted
578 * in the following way:
580 * type;uid;gid;perm;description<NUL>
582 * If successful, we return the amount of description available, irrespective
583 * of how much we may have copied into the buffer.
585 long keyctl_describe_key(key_serial_t keyid,
589 struct key *key, *instkey;
593 int desclen, infolen;
595 key_ref = lookup_user_key(keyid, KEY_LOOKUP_PARTIAL, KEY_NEED_VIEW);
596 if (IS_ERR(key_ref)) {
597 /* viewing a key under construction is permitted if we have the
598 * authorisation token handy */
599 if (PTR_ERR(key_ref) == -EACCES) {
600 instkey = key_get_instantiation_authkey(keyid);
601 if (!IS_ERR(instkey)) {
603 key_ref = lookup_user_key(keyid,
606 if (!IS_ERR(key_ref))
611 ret = PTR_ERR(key_ref);
616 key = key_ref_to_ptr(key_ref);
617 desclen = strlen(key->description);
619 /* calculate how much information we're going to return */
621 infobuf = kasprintf(GFP_KERNEL,
624 from_kuid_munged(current_user_ns(), key->uid),
625 from_kgid_munged(current_user_ns(), key->gid),
629 infolen = strlen(infobuf);
630 ret = infolen + desclen + 1;
632 /* consider returning the data */
633 if (buffer && buflen >= ret) {
634 if (copy_to_user(buffer, infobuf, infolen) != 0 ||
635 copy_to_user(buffer + infolen, key->description,
642 key_ref_put(key_ref);
648 * Search the specified keyring and any keyrings it links to for a matching
649 * key. Only keyrings that grant the caller Search permission will be searched
650 * (this includes the starting keyring). Only keys with Search permission can
653 * If successful, the found key will be linked to the destination keyring if
654 * supplied and the key has Link permission, and the found key ID will be
657 long keyctl_keyring_search(key_serial_t ringid,
658 const char __user *_type,
659 const char __user *_description,
660 key_serial_t destringid)
662 struct key_type *ktype;
663 key_ref_t keyring_ref, key_ref, dest_ref;
664 char type[32], *description;
667 /* pull the type and description into kernel space */
668 ret = key_get_type_from_user(type, _type, sizeof(type));
672 description = strndup_user(_description, KEY_MAX_DESC_SIZE);
673 if (IS_ERR(description)) {
674 ret = PTR_ERR(description);
678 /* get the keyring at which to begin the search */
679 keyring_ref = lookup_user_key(ringid, 0, KEY_NEED_SEARCH);
680 if (IS_ERR(keyring_ref)) {
681 ret = PTR_ERR(keyring_ref);
685 /* get the destination keyring if specified */
688 dest_ref = lookup_user_key(destringid, KEY_LOOKUP_CREATE,
690 if (IS_ERR(dest_ref)) {
691 ret = PTR_ERR(dest_ref);
696 /* find the key type */
697 ktype = key_type_lookup(type);
699 ret = PTR_ERR(ktype);
704 key_ref = keyring_search(keyring_ref, ktype, description);
705 if (IS_ERR(key_ref)) {
706 ret = PTR_ERR(key_ref);
708 /* treat lack or presence of a negative key the same */
714 /* link the resulting key to the destination keyring if we can */
716 ret = key_permission(key_ref, KEY_NEED_LINK);
720 ret = key_link(key_ref_to_ptr(dest_ref), key_ref_to_ptr(key_ref));
725 ret = key_ref_to_ptr(key_ref)->serial;
728 key_ref_put(key_ref);
732 key_ref_put(dest_ref);
734 key_ref_put(keyring_ref);
742 * Read a key's payload.
744 * The key must either grant the caller Read permission, or it must grant the
745 * caller Search permission when searched for from the process keyrings.
747 * If successful, we place up to buflen bytes of data into the buffer, if one
748 * is provided, and return the amount of data that is available in the key,
749 * irrespective of how much we copied into the buffer.
751 long keyctl_read_key(key_serial_t keyid, char __user *buffer, size_t buflen)
757 /* find the key first */
758 key_ref = lookup_user_key(keyid, 0, 0);
759 if (IS_ERR(key_ref)) {
764 key = key_ref_to_ptr(key_ref);
766 /* see if we can read it directly */
767 ret = key_permission(key_ref, KEY_NEED_READ);
773 /* we can't; see if it's searchable from this process's keyrings
774 * - we automatically take account of the fact that it may be
775 * dangling off an instantiation key
777 if (!is_key_possessed(key_ref)) {
782 /* the key is probably readable - now try to read it */
785 if (key->type->read) {
786 /* Read the data with the semaphore held (since we might sleep)
787 * to protect against the key being updated or revoked.
789 down_read(&key->sem);
790 ret = key_validate(key);
792 ret = key->type->read(key, buffer, buflen);
803 * Change the ownership of a key
805 * The key must grant the caller Setattr permission for this to work, though
806 * the key need not be fully instantiated yet. For the UID to be changed, or
807 * for the GID to be changed to a group the caller is not a member of, the
808 * caller must have sysadmin capability. If either uid or gid is -1 then that
809 * attribute is not changed.
811 * If the UID is to be changed, the new user must have sufficient quota to
812 * accept the key. The quota deduction will be removed from the old user to
813 * the new user should the attribute be changed.
815 * If successful, 0 will be returned.
817 long keyctl_chown_key(key_serial_t id, uid_t user, gid_t group)
819 struct key_user *newowner, *zapowner = NULL;
826 uid = make_kuid(current_user_ns(), user);
827 gid = make_kgid(current_user_ns(), group);
829 if ((user != (uid_t) -1) && !uid_valid(uid))
831 if ((group != (gid_t) -1) && !gid_valid(gid))
835 if (user == (uid_t) -1 && group == (gid_t) -1)
838 key_ref = lookup_user_key(id, KEY_LOOKUP_CREATE | KEY_LOOKUP_PARTIAL,
840 if (IS_ERR(key_ref)) {
841 ret = PTR_ERR(key_ref);
845 key = key_ref_to_ptr(key_ref);
847 /* make the changes with the locks held to prevent chown/chown races */
849 down_write(&key->sem);
851 if (!capable(CAP_SYS_ADMIN)) {
852 /* only the sysadmin can chown a key to some other UID */
853 if (user != (uid_t) -1 && !uid_eq(key->uid, uid))
856 /* only the sysadmin can set the key's GID to a group other
857 * than one of those that the current process subscribes to */
858 if (group != (gid_t) -1 && !gid_eq(gid, key->gid) && !in_group_p(gid))
863 if (user != (uid_t) -1 && !uid_eq(uid, key->uid)) {
865 newowner = key_user_lookup(uid);
869 /* transfer the quota burden to the new user */
870 if (test_bit(KEY_FLAG_IN_QUOTA, &key->flags)) {
871 unsigned maxkeys = uid_eq(uid, GLOBAL_ROOT_UID) ?
872 key_quota_root_maxkeys : key_quota_maxkeys;
873 unsigned maxbytes = uid_eq(uid, GLOBAL_ROOT_UID) ?
874 key_quota_root_maxbytes : key_quota_maxbytes;
876 spin_lock(&newowner->lock);
877 if (newowner->qnkeys + 1 >= maxkeys ||
878 newowner->qnbytes + key->quotalen >= maxbytes ||
879 newowner->qnbytes + key->quotalen <
884 newowner->qnbytes += key->quotalen;
885 spin_unlock(&newowner->lock);
887 spin_lock(&key->user->lock);
889 key->user->qnbytes -= key->quotalen;
890 spin_unlock(&key->user->lock);
893 atomic_dec(&key->user->nkeys);
894 atomic_inc(&newowner->nkeys);
896 if (test_bit(KEY_FLAG_INSTANTIATED, &key->flags)) {
897 atomic_dec(&key->user->nikeys);
898 atomic_inc(&newowner->nikeys);
901 zapowner = key->user;
902 key->user = newowner;
907 if (group != (gid_t) -1)
916 key_user_put(zapowner);
921 spin_unlock(&newowner->lock);
928 * Change the permission mask on a key.
930 * The key must grant the caller Setattr permission for this to work, though
931 * the key need not be fully instantiated yet. If the caller does not have
932 * sysadmin capability, it may only change the permission on keys that it owns.
934 long keyctl_setperm_key(key_serial_t id, key_perm_t perm)
941 if (perm & ~(KEY_POS_ALL | KEY_USR_ALL | KEY_GRP_ALL | KEY_OTH_ALL))
944 key_ref = lookup_user_key(id, KEY_LOOKUP_CREATE | KEY_LOOKUP_PARTIAL,
946 if (IS_ERR(key_ref)) {
947 ret = PTR_ERR(key_ref);
951 key = key_ref_to_ptr(key_ref);
953 /* make the changes with the locks held to prevent chown/chmod races */
955 down_write(&key->sem);
957 /* if we're not the sysadmin, we can only change a key that we own */
958 if (capable(CAP_SYS_ADMIN) || uid_eq(key->uid, current_fsuid())) {
970 * Get the destination keyring for instantiation and check that the caller has
971 * Write permission on it.
973 static long get_instantiation_keyring(key_serial_t ringid,
974 struct request_key_auth *rka,
975 struct key **_dest_keyring)
979 *_dest_keyring = NULL;
981 /* just return a NULL pointer if we weren't asked to make a link */
985 /* if a specific keyring is nominated by ID, then use that */
987 dkref = lookup_user_key(ringid, KEY_LOOKUP_CREATE, KEY_NEED_WRITE);
989 return PTR_ERR(dkref);
990 *_dest_keyring = key_ref_to_ptr(dkref);
994 if (ringid == KEY_SPEC_REQKEY_AUTH_KEY)
997 /* otherwise specify the destination keyring recorded in the
998 * authorisation key (any KEY_SPEC_*_KEYRING) */
999 if (ringid >= KEY_SPEC_REQUESTOR_KEYRING) {
1000 *_dest_keyring = key_get(rka->dest_keyring);
1008 * Change the request_key authorisation key on the current process.
1010 static int keyctl_change_reqkey_auth(struct key *key)
1014 new = prepare_creds();
1018 key_put(new->request_key_auth);
1019 new->request_key_auth = key_get(key);
1021 return commit_creds(new);
1025 * Instantiate a key with the specified payload and link the key into the
1026 * destination keyring if one is given.
1028 * The caller must have the appropriate instantiation permit set for this to
1029 * work (see keyctl_assume_authority). No other permissions are required.
1031 * If successful, 0 will be returned.
1033 long keyctl_instantiate_key_common(key_serial_t id,
1034 struct iov_iter *from,
1035 key_serial_t ringid)
1037 const struct cred *cred = current_cred();
1038 struct request_key_auth *rka;
1039 struct key *instkey, *dest_keyring;
1040 size_t plen = from ? iov_iter_count(from) : 0;
1044 kenter("%d,,%zu,%d", id, plen, ringid);
1050 if (plen > 1024 * 1024 - 1)
1053 /* the appropriate instantiation authorisation key must have been
1054 * assumed before calling this */
1056 instkey = cred->request_key_auth;
1060 rka = instkey->payload.data[0];
1061 if (rka->target_key->serial != id)
1064 /* pull the payload in if one was supplied */
1069 payload = kvmalloc(plen, GFP_KERNEL);
1074 if (!copy_from_iter_full(payload, plen, from))
1078 /* find the destination keyring amongst those belonging to the
1079 * requesting task */
1080 ret = get_instantiation_keyring(ringid, rka, &dest_keyring);
1084 /* instantiate the key and link it into a keyring */
1085 ret = key_instantiate_and_link(rka->target_key, payload, plen,
1086 dest_keyring, instkey);
1088 key_put(dest_keyring);
1090 /* discard the assumed authority if it's just been disabled by
1091 * instantiation of the key */
1093 keyctl_change_reqkey_auth(NULL);
1102 * Instantiate a key with the specified payload and link the key into the
1103 * destination keyring if one is given.
1105 * The caller must have the appropriate instantiation permit set for this to
1106 * work (see keyctl_assume_authority). No other permissions are required.
1108 * If successful, 0 will be returned.
1110 long keyctl_instantiate_key(key_serial_t id,
1111 const void __user *_payload,
1113 key_serial_t ringid)
1115 if (_payload && plen) {
1117 struct iov_iter from;
1120 ret = import_single_range(WRITE, (void __user *)_payload, plen,
1125 return keyctl_instantiate_key_common(id, &from, ringid);
1128 return keyctl_instantiate_key_common(id, NULL, ringid);
1132 * Instantiate a key with the specified multipart payload and link the key into
1133 * the destination keyring if one is given.
1135 * The caller must have the appropriate instantiation permit set for this to
1136 * work (see keyctl_assume_authority). No other permissions are required.
1138 * If successful, 0 will be returned.
1140 long keyctl_instantiate_key_iov(key_serial_t id,
1141 const struct iovec __user *_payload_iov,
1143 key_serial_t ringid)
1145 struct iovec iovstack[UIO_FASTIOV], *iov = iovstack;
1146 struct iov_iter from;
1152 ret = import_iovec(WRITE, _payload_iov, ioc,
1153 ARRAY_SIZE(iovstack), &iov, &from);
1156 ret = keyctl_instantiate_key_common(id, &from, ringid);
1162 * Negatively instantiate the key with the given timeout (in seconds) and link
1163 * the key into the destination keyring if one is given.
1165 * The caller must have the appropriate instantiation permit set for this to
1166 * work (see keyctl_assume_authority). No other permissions are required.
1168 * The key and any links to the key will be automatically garbage collected
1169 * after the timeout expires.
1171 * Negative keys are used to rate limit repeated request_key() calls by causing
1172 * them to return -ENOKEY until the negative key expires.
1174 * If successful, 0 will be returned.
1176 long keyctl_negate_key(key_serial_t id, unsigned timeout, key_serial_t ringid)
1178 return keyctl_reject_key(id, timeout, ENOKEY, ringid);
1182 * Negatively instantiate the key with the given timeout (in seconds) and error
1183 * code and link the key into the destination keyring if one is given.
1185 * The caller must have the appropriate instantiation permit set for this to
1186 * work (see keyctl_assume_authority). No other permissions are required.
1188 * The key and any links to the key will be automatically garbage collected
1189 * after the timeout expires.
1191 * Negative keys are used to rate limit repeated request_key() calls by causing
1192 * them to return the specified error code until the negative key expires.
1194 * If successful, 0 will be returned.
1196 long keyctl_reject_key(key_serial_t id, unsigned timeout, unsigned error,
1197 key_serial_t ringid)
1199 const struct cred *cred = current_cred();
1200 struct request_key_auth *rka;
1201 struct key *instkey, *dest_keyring;
1204 kenter("%d,%u,%u,%d", id, timeout, error, ringid);
1206 /* must be a valid error code and mustn't be a kernel special */
1208 error >= MAX_ERRNO ||
1209 error == ERESTARTSYS ||
1210 error == ERESTARTNOINTR ||
1211 error == ERESTARTNOHAND ||
1212 error == ERESTART_RESTARTBLOCK)
1215 /* the appropriate instantiation authorisation key must have been
1216 * assumed before calling this */
1218 instkey = cred->request_key_auth;
1222 rka = instkey->payload.data[0];
1223 if (rka->target_key->serial != id)
1226 /* find the destination keyring if present (which must also be
1228 ret = get_instantiation_keyring(ringid, rka, &dest_keyring);
1232 /* instantiate the key and link it into a keyring */
1233 ret = key_reject_and_link(rka->target_key, timeout, error,
1234 dest_keyring, instkey);
1236 key_put(dest_keyring);
1238 /* discard the assumed authority if it's just been disabled by
1239 * instantiation of the key */
1241 keyctl_change_reqkey_auth(NULL);
1248 * Read or set the default keyring in which request_key() will cache keys and
1249 * return the old setting.
1251 * If a thread or process keyring is specified then it will be created if it
1252 * doesn't yet exist. The old setting will be returned if successful.
1254 long keyctl_set_reqkey_keyring(int reqkey_defl)
1257 int ret, old_setting;
1259 old_setting = current_cred_xxx(jit_keyring);
1261 if (reqkey_defl == KEY_REQKEY_DEFL_NO_CHANGE)
1264 new = prepare_creds();
1268 switch (reqkey_defl) {
1269 case KEY_REQKEY_DEFL_THREAD_KEYRING:
1270 ret = install_thread_keyring_to_cred(new);
1275 case KEY_REQKEY_DEFL_PROCESS_KEYRING:
1276 ret = install_process_keyring_to_cred(new);
1281 case KEY_REQKEY_DEFL_DEFAULT:
1282 case KEY_REQKEY_DEFL_SESSION_KEYRING:
1283 case KEY_REQKEY_DEFL_USER_KEYRING:
1284 case KEY_REQKEY_DEFL_USER_SESSION_KEYRING:
1285 case KEY_REQKEY_DEFL_REQUESTOR_KEYRING:
1288 case KEY_REQKEY_DEFL_NO_CHANGE:
1289 case KEY_REQKEY_DEFL_GROUP_KEYRING:
1296 new->jit_keyring = reqkey_defl;
1305 * Set or clear the timeout on a key.
1307 * Either the key must grant the caller Setattr permission or else the caller
1308 * must hold an instantiation authorisation token for the key.
1310 * The timeout is either 0 to clear the timeout, or a number of seconds from
1311 * the current time. The key and any links to the key will be automatically
1312 * garbage collected after the timeout expires.
1314 * Keys with KEY_FLAG_KEEP set should not be timed out.
1316 * If successful, 0 is returned.
1318 long keyctl_set_timeout(key_serial_t id, unsigned timeout)
1320 struct key *key, *instkey;
1324 key_ref = lookup_user_key(id, KEY_LOOKUP_CREATE | KEY_LOOKUP_PARTIAL,
1326 if (IS_ERR(key_ref)) {
1327 /* setting the timeout on a key under construction is permitted
1328 * if we have the authorisation token handy */
1329 if (PTR_ERR(key_ref) == -EACCES) {
1330 instkey = key_get_instantiation_authkey(id);
1331 if (!IS_ERR(instkey)) {
1333 key_ref = lookup_user_key(id,
1336 if (!IS_ERR(key_ref))
1341 ret = PTR_ERR(key_ref);
1346 key = key_ref_to_ptr(key_ref);
1348 if (test_bit(KEY_FLAG_KEEP, &key->flags))
1351 key_set_timeout(key, timeout);
1359 * Assume (or clear) the authority to instantiate the specified key.
1361 * This sets the authoritative token currently in force for key instantiation.
1362 * This must be done for a key to be instantiated. It has the effect of making
1363 * available all the keys from the caller of the request_key() that created a
1364 * key to request_key() calls made by the caller of this function.
1366 * The caller must have the instantiation key in their process keyrings with a
1367 * Search permission grant available to the caller.
1369 * If the ID given is 0, then the setting will be cleared and 0 returned.
1371 * If the ID given has a matching an authorisation key, then that key will be
1372 * set and its ID will be returned. The authorisation key can be read to get
1373 * the callout information passed to request_key().
1375 long keyctl_assume_authority(key_serial_t id)
1377 struct key *authkey;
1380 /* special key IDs aren't permitted */
1385 /* we divest ourselves of authority if given an ID of 0 */
1387 ret = keyctl_change_reqkey_auth(NULL);
1391 /* attempt to assume the authority temporarily granted to us whilst we
1392 * instantiate the specified key
1393 * - the authorisation key must be in the current task's keyrings
1396 authkey = key_get_instantiation_authkey(id);
1397 if (IS_ERR(authkey)) {
1398 ret = PTR_ERR(authkey);
1402 ret = keyctl_change_reqkey_auth(authkey);
1407 ret = authkey->serial;
1413 * Get a key's the LSM security label.
1415 * The key must grant the caller View permission for this to work.
1417 * If there's a buffer, then up to buflen bytes of data will be placed into it.
1419 * If successful, the amount of information available will be returned,
1420 * irrespective of how much was copied (including the terminal NUL).
1422 long keyctl_get_security(key_serial_t keyid,
1423 char __user *buffer,
1426 struct key *key, *instkey;
1431 key_ref = lookup_user_key(keyid, KEY_LOOKUP_PARTIAL, KEY_NEED_VIEW);
1432 if (IS_ERR(key_ref)) {
1433 if (PTR_ERR(key_ref) != -EACCES)
1434 return PTR_ERR(key_ref);
1436 /* viewing a key under construction is also permitted if we
1437 * have the authorisation token handy */
1438 instkey = key_get_instantiation_authkey(keyid);
1439 if (IS_ERR(instkey))
1440 return PTR_ERR(instkey);
1443 key_ref = lookup_user_key(keyid, KEY_LOOKUP_PARTIAL, 0);
1444 if (IS_ERR(key_ref))
1445 return PTR_ERR(key_ref);
1448 key = key_ref_to_ptr(key_ref);
1449 ret = security_key_getsecurity(key, &context);
1451 /* if no information was returned, give userspace an empty
1454 if (buffer && buflen > 0 &&
1455 copy_to_user(buffer, "", 1) != 0)
1457 } else if (ret > 0) {
1458 /* return as much data as there's room for */
1459 if (buffer && buflen > 0) {
1463 if (copy_to_user(buffer, context, buflen) != 0)
1470 key_ref_put(key_ref);
1475 * Attempt to install the calling process's session keyring on the process's
1478 * The keyring must exist and must grant the caller LINK permission, and the
1479 * parent process must be single-threaded and must have the same effective
1480 * ownership as this process and mustn't be SUID/SGID.
1482 * The keyring will be emplaced on the parent when it next resumes userspace.
1484 * If successful, 0 will be returned.
1486 long keyctl_session_to_parent(void)
1488 struct task_struct *me, *parent;
1489 const struct cred *mycred, *pcred;
1490 struct callback_head *newwork, *oldwork;
1491 key_ref_t keyring_r;
1495 keyring_r = lookup_user_key(KEY_SPEC_SESSION_KEYRING, 0, KEY_NEED_LINK);
1496 if (IS_ERR(keyring_r))
1497 return PTR_ERR(keyring_r);
1501 /* our parent is going to need a new cred struct, a new tgcred struct
1502 * and new security data, so we allocate them here to prevent ENOMEM in
1504 cred = cred_alloc_blank();
1507 newwork = &cred->rcu;
1509 cred->session_keyring = key_ref_to_ptr(keyring_r);
1511 init_task_work(newwork, key_change_session_keyring);
1515 write_lock_irq(&tasklist_lock);
1519 parent = me->real_parent;
1521 /* the parent mustn't be init and mustn't be a kernel thread */
1522 if (parent->pid <= 1 || !parent->mm)
1525 /* the parent must be single threaded */
1526 if (!thread_group_empty(parent))
1529 /* the parent and the child must have different session keyrings or
1530 * there's no point */
1531 mycred = current_cred();
1532 pcred = __task_cred(parent);
1533 if (mycred == pcred ||
1534 mycred->session_keyring == pcred->session_keyring) {
1539 /* the parent must have the same effective ownership and mustn't be
1541 if (!uid_eq(pcred->uid, mycred->euid) ||
1542 !uid_eq(pcred->euid, mycred->euid) ||
1543 !uid_eq(pcred->suid, mycred->euid) ||
1544 !gid_eq(pcred->gid, mycred->egid) ||
1545 !gid_eq(pcred->egid, mycred->egid) ||
1546 !gid_eq(pcred->sgid, mycred->egid))
1549 /* the keyrings must have the same UID */
1550 if ((pcred->session_keyring &&
1551 !uid_eq(pcred->session_keyring->uid, mycred->euid)) ||
1552 !uid_eq(mycred->session_keyring->uid, mycred->euid))
1555 /* cancel an already pending keyring replacement */
1556 oldwork = task_work_cancel(parent, key_change_session_keyring);
1558 /* the replacement session keyring is applied just prior to userspace
1560 ret = task_work_add(parent, newwork, true);
1564 write_unlock_irq(&tasklist_lock);
1567 put_cred(container_of(oldwork, struct cred, rcu));
1573 key_ref_put(keyring_r);
1578 * Apply a restriction to a given keyring.
1580 * The caller must have Setattr permission to change keyring restrictions.
1582 * The requested type name may be a NULL pointer to reject all attempts
1583 * to link to the keyring. If _type is non-NULL, _restriction can be
1584 * NULL or a pointer to a string describing the restriction. If _type is
1585 * NULL, _restriction must also be NULL.
1587 * Returns 0 if successful.
1589 long keyctl_restrict_keyring(key_serial_t id, const char __user *_type,
1590 const char __user *_restriction)
1593 bool link_reject = !_type;
1595 char *restriction = NULL;
1598 key_ref = lookup_user_key(id, 0, KEY_NEED_SETATTR);
1599 if (IS_ERR(key_ref))
1600 return PTR_ERR(key_ref);
1603 ret = key_get_type_from_user(type, _type, sizeof(type));
1614 restriction = strndup_user(_restriction, PAGE_SIZE);
1615 if (IS_ERR(restriction)) {
1616 ret = PTR_ERR(restriction);
1621 ret = keyring_restrict(key_ref, link_reject ? NULL : type, restriction);
1625 key_ref_put(key_ref);
1631 * The key control system call
1633 SYSCALL_DEFINE5(keyctl, int, option, unsigned long, arg2, unsigned long, arg3,
1634 unsigned long, arg4, unsigned long, arg5)
1637 case KEYCTL_GET_KEYRING_ID:
1638 return keyctl_get_keyring_ID((key_serial_t) arg2,
1641 case KEYCTL_JOIN_SESSION_KEYRING:
1642 return keyctl_join_session_keyring((const char __user *) arg2);
1645 return keyctl_update_key((key_serial_t) arg2,
1646 (const void __user *) arg3,
1650 return keyctl_revoke_key((key_serial_t) arg2);
1652 case KEYCTL_DESCRIBE:
1653 return keyctl_describe_key((key_serial_t) arg2,
1654 (char __user *) arg3,
1658 return keyctl_keyring_clear((key_serial_t) arg2);
1661 return keyctl_keyring_link((key_serial_t) arg2,
1662 (key_serial_t) arg3);
1665 return keyctl_keyring_unlink((key_serial_t) arg2,
1666 (key_serial_t) arg3);
1669 return keyctl_keyring_search((key_serial_t) arg2,
1670 (const char __user *) arg3,
1671 (const char __user *) arg4,
1672 (key_serial_t) arg5);
1675 return keyctl_read_key((key_serial_t) arg2,
1676 (char __user *) arg3,
1680 return keyctl_chown_key((key_serial_t) arg2,
1684 case KEYCTL_SETPERM:
1685 return keyctl_setperm_key((key_serial_t) arg2,
1688 case KEYCTL_INSTANTIATE:
1689 return keyctl_instantiate_key((key_serial_t) arg2,
1690 (const void __user *) arg3,
1692 (key_serial_t) arg5);
1695 return keyctl_negate_key((key_serial_t) arg2,
1697 (key_serial_t) arg4);
1699 case KEYCTL_SET_REQKEY_KEYRING:
1700 return keyctl_set_reqkey_keyring(arg2);
1702 case KEYCTL_SET_TIMEOUT:
1703 return keyctl_set_timeout((key_serial_t) arg2,
1706 case KEYCTL_ASSUME_AUTHORITY:
1707 return keyctl_assume_authority((key_serial_t) arg2);
1709 case KEYCTL_GET_SECURITY:
1710 return keyctl_get_security((key_serial_t) arg2,
1711 (char __user *) arg3,
1714 case KEYCTL_SESSION_TO_PARENT:
1715 return keyctl_session_to_parent();
1718 return keyctl_reject_key((key_serial_t) arg2,
1721 (key_serial_t) arg5);
1723 case KEYCTL_INSTANTIATE_IOV:
1724 return keyctl_instantiate_key_iov(
1725 (key_serial_t) arg2,
1726 (const struct iovec __user *) arg3,
1728 (key_serial_t) arg5);
1730 case KEYCTL_INVALIDATE:
1731 return keyctl_invalidate_key((key_serial_t) arg2);
1733 case KEYCTL_GET_PERSISTENT:
1734 return keyctl_get_persistent((uid_t)arg2, (key_serial_t)arg3);
1736 case KEYCTL_DH_COMPUTE:
1737 return keyctl_dh_compute((struct keyctl_dh_params __user *) arg2,
1738 (char __user *) arg3, (size_t) arg4,
1739 (struct keyctl_kdf_params __user *) arg5);
1741 case KEYCTL_RESTRICT_KEYRING:
1742 return keyctl_restrict_keyring((key_serial_t) arg2,
1743 (const char __user *) arg3,
1744 (const char __user *) arg4);