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);
136 memzero_explicit(payload, plen);
146 * Search the process keyrings and keyring trees linked from those for a
147 * matching key. Keyrings must have appropriate Search permission to be
150 * If a key is found, it will be attached to the destination keyring if there's
151 * one specified and the serial number of the key will be returned.
153 * If no key is found, /sbin/request-key will be invoked if _callout_info is
154 * non-NULL in an attempt to create a key. The _callout_info string will be
155 * passed to /sbin/request-key to aid with completing the request. If the
156 * _callout_info string is "" then it will be changed to "-".
158 SYSCALL_DEFINE4(request_key, const char __user *, _type,
159 const char __user *, _description,
160 const char __user *, _callout_info,
161 key_serial_t, destringid)
163 struct key_type *ktype;
167 char type[32], *description, *callout_info;
170 /* pull the type into kernel space */
171 ret = key_get_type_from_user(type, _type, sizeof(type));
175 /* pull the description into kernel space */
176 description = strndup_user(_description, KEY_MAX_DESC_SIZE);
177 if (IS_ERR(description)) {
178 ret = PTR_ERR(description);
182 /* pull the callout info into kernel space */
186 callout_info = strndup_user(_callout_info, PAGE_SIZE);
187 if (IS_ERR(callout_info)) {
188 ret = PTR_ERR(callout_info);
191 callout_len = strlen(callout_info);
194 /* get the destination keyring if specified */
197 dest_ref = lookup_user_key(destringid, KEY_LOOKUP_CREATE,
199 if (IS_ERR(dest_ref)) {
200 ret = PTR_ERR(dest_ref);
205 /* find the key type */
206 ktype = key_type_lookup(type);
208 ret = PTR_ERR(ktype);
213 key = request_key_and_link(ktype, description, callout_info,
214 callout_len, NULL, key_ref_to_ptr(dest_ref),
221 /* wait for the key to finish being constructed */
222 ret = wait_for_key_construction(key, 1);
233 key_ref_put(dest_ref);
243 * Get the ID of the specified process keyring.
245 * The requested keyring must have search permission to be found.
247 * If successful, the ID of the requested keyring will be returned.
249 long keyctl_get_keyring_ID(key_serial_t id, int create)
252 unsigned long lflags;
255 lflags = create ? KEY_LOOKUP_CREATE : 0;
256 key_ref = lookup_user_key(id, lflags, KEY_NEED_SEARCH);
257 if (IS_ERR(key_ref)) {
258 ret = PTR_ERR(key_ref);
262 ret = key_ref_to_ptr(key_ref)->serial;
263 key_ref_put(key_ref);
269 * Join a (named) session keyring.
271 * Create and join an anonymous session keyring or join a named session
272 * keyring, creating it if necessary. A named session keyring must have Search
273 * permission for it to be joined. Session keyrings without this permit will
274 * be skipped over. It is not permitted for userspace to create or join
275 * keyrings whose name begin with a dot.
277 * If successful, the ID of the joined session keyring will be returned.
279 long keyctl_join_session_keyring(const char __user *_name)
284 /* fetch the name from userspace */
287 name = strndup_user(_name, KEY_MAX_DESC_SIZE);
298 /* join the session */
299 ret = join_session_keyring(name);
307 * Update a key's data payload from the given data.
309 * The key must grant the caller Write permission and the key type must support
310 * updating for this to work. A negative key can be positively instantiated
313 * If successful, 0 will be returned. If the key type does not support
314 * updating, then -EOPNOTSUPP will be returned.
316 long keyctl_update_key(key_serial_t id,
317 const void __user *_payload,
325 if (plen > PAGE_SIZE)
328 /* pull the payload in if one was supplied */
332 payload = kmalloc(plen, GFP_KERNEL);
337 if (copy_from_user(payload, _payload, plen) != 0)
341 /* find the target key (which must be writable) */
342 key_ref = lookup_user_key(id, 0, KEY_NEED_WRITE);
343 if (IS_ERR(key_ref)) {
344 ret = PTR_ERR(key_ref);
349 ret = key_update(key_ref, payload, plen);
351 key_ref_put(key_ref);
361 * The key must be grant the caller Write or Setattr permission for this to
362 * work. The key type should give up its quota claim when revoked. The key
363 * and any links to the key will be automatically garbage collected after a
364 * certain amount of time (/proc/sys/kernel/keys/gc_delay).
366 * Keys with KEY_FLAG_KEEP set should not be revoked.
368 * If successful, 0 is returned.
370 long keyctl_revoke_key(key_serial_t id)
376 key_ref = lookup_user_key(id, 0, KEY_NEED_WRITE);
377 if (IS_ERR(key_ref)) {
378 ret = PTR_ERR(key_ref);
381 key_ref = lookup_user_key(id, 0, KEY_NEED_SETATTR);
382 if (IS_ERR(key_ref)) {
383 ret = PTR_ERR(key_ref);
388 key = key_ref_to_ptr(key_ref);
390 if (test_bit(KEY_FLAG_KEEP, &key->flags))
395 key_ref_put(key_ref);
403 * The key must be grant the caller Invalidate permission for this to work.
404 * The key and any links to the key will be automatically garbage collected
407 * Keys with KEY_FLAG_KEEP set should not be invalidated.
409 * If successful, 0 is returned.
411 long keyctl_invalidate_key(key_serial_t id)
419 key_ref = lookup_user_key(id, 0, KEY_NEED_SEARCH);
420 if (IS_ERR(key_ref)) {
421 ret = PTR_ERR(key_ref);
423 /* Root is permitted to invalidate certain special keys */
424 if (capable(CAP_SYS_ADMIN)) {
425 key_ref = lookup_user_key(id, 0, 0);
428 if (test_bit(KEY_FLAG_ROOT_CAN_INVAL,
429 &key_ref_to_ptr(key_ref)->flags))
438 key = key_ref_to_ptr(key_ref);
440 if (test_bit(KEY_FLAG_KEEP, &key->flags))
445 key_ref_put(key_ref);
447 kleave(" = %ld", ret);
452 * Clear the specified keyring, creating an empty process keyring if one of the
453 * special keyring IDs is used.
455 * The keyring must grant the caller Write permission and not have
456 * KEY_FLAG_KEEP set for this to work. If successful, 0 will be returned.
458 long keyctl_keyring_clear(key_serial_t ringid)
460 key_ref_t keyring_ref;
464 keyring_ref = lookup_user_key(ringid, KEY_LOOKUP_CREATE, KEY_NEED_WRITE);
465 if (IS_ERR(keyring_ref)) {
466 ret = PTR_ERR(keyring_ref);
468 /* Root is permitted to invalidate certain special keyrings */
469 if (capable(CAP_SYS_ADMIN)) {
470 keyring_ref = lookup_user_key(ringid, 0, 0);
471 if (IS_ERR(keyring_ref))
473 if (test_bit(KEY_FLAG_ROOT_CAN_CLEAR,
474 &key_ref_to_ptr(keyring_ref)->flags))
483 keyring = key_ref_to_ptr(keyring_ref);
484 if (test_bit(KEY_FLAG_KEEP, &keyring->flags))
487 ret = keyring_clear(keyring);
489 key_ref_put(keyring_ref);
495 * Create a link from a keyring to a key if there's no matching key in the
496 * keyring, otherwise replace the link to the matching key with a link to the
499 * The key must grant the caller Link permission and the the keyring must grant
500 * the caller Write permission. Furthermore, if an additional link is created,
501 * the keyring's quota will be extended.
503 * If successful, 0 will be returned.
505 long keyctl_keyring_link(key_serial_t id, key_serial_t ringid)
507 key_ref_t keyring_ref, key_ref;
510 keyring_ref = lookup_user_key(ringid, KEY_LOOKUP_CREATE, KEY_NEED_WRITE);
511 if (IS_ERR(keyring_ref)) {
512 ret = PTR_ERR(keyring_ref);
516 key_ref = lookup_user_key(id, KEY_LOOKUP_CREATE, KEY_NEED_LINK);
517 if (IS_ERR(key_ref)) {
518 ret = PTR_ERR(key_ref);
522 ret = key_link(key_ref_to_ptr(keyring_ref), key_ref_to_ptr(key_ref));
524 key_ref_put(key_ref);
526 key_ref_put(keyring_ref);
532 * Unlink a key from a keyring.
534 * The keyring must grant the caller Write permission for this to work; the key
535 * itself need not grant the caller anything. If the last link to a key is
536 * removed then that key will be scheduled for destruction.
538 * Keys or keyrings with KEY_FLAG_KEEP set should not be unlinked.
540 * If successful, 0 will be returned.
542 long keyctl_keyring_unlink(key_serial_t id, key_serial_t ringid)
544 key_ref_t keyring_ref, key_ref;
545 struct key *keyring, *key;
548 keyring_ref = lookup_user_key(ringid, 0, KEY_NEED_WRITE);
549 if (IS_ERR(keyring_ref)) {
550 ret = PTR_ERR(keyring_ref);
554 key_ref = lookup_user_key(id, KEY_LOOKUP_FOR_UNLINK, 0);
555 if (IS_ERR(key_ref)) {
556 ret = PTR_ERR(key_ref);
560 keyring = key_ref_to_ptr(keyring_ref);
561 key = key_ref_to_ptr(key_ref);
562 if (test_bit(KEY_FLAG_KEEP, &keyring->flags) &&
563 test_bit(KEY_FLAG_KEEP, &key->flags))
566 ret = key_unlink(keyring, key);
568 key_ref_put(key_ref);
570 key_ref_put(keyring_ref);
576 * Return a description of a key to userspace.
578 * The key must grant the caller View permission for this to work.
580 * If there's a buffer, we place up to buflen bytes of data into it formatted
581 * in the following way:
583 * type;uid;gid;perm;description<NUL>
585 * If successful, we return the amount of description available, irrespective
586 * of how much we may have copied into the buffer.
588 long keyctl_describe_key(key_serial_t keyid,
592 struct key *key, *instkey;
596 int desclen, infolen;
598 key_ref = lookup_user_key(keyid, KEY_LOOKUP_PARTIAL, KEY_NEED_VIEW);
599 if (IS_ERR(key_ref)) {
600 /* viewing a key under construction is permitted if we have the
601 * authorisation token handy */
602 if (PTR_ERR(key_ref) == -EACCES) {
603 instkey = key_get_instantiation_authkey(keyid);
604 if (!IS_ERR(instkey)) {
606 key_ref = lookup_user_key(keyid,
609 if (!IS_ERR(key_ref))
614 ret = PTR_ERR(key_ref);
619 key = key_ref_to_ptr(key_ref);
620 desclen = strlen(key->description);
622 /* calculate how much information we're going to return */
624 infobuf = kasprintf(GFP_KERNEL,
627 from_kuid_munged(current_user_ns(), key->uid),
628 from_kgid_munged(current_user_ns(), key->gid),
632 infolen = strlen(infobuf);
633 ret = infolen + desclen + 1;
635 /* consider returning the data */
636 if (buffer && buflen >= ret) {
637 if (copy_to_user(buffer, infobuf, infolen) != 0 ||
638 copy_to_user(buffer + infolen, key->description,
645 key_ref_put(key_ref);
651 * Search the specified keyring and any keyrings it links to for a matching
652 * key. Only keyrings that grant the caller Search permission will be searched
653 * (this includes the starting keyring). Only keys with Search permission can
656 * If successful, the found key will be linked to the destination keyring if
657 * supplied and the key has Link permission, and the found key ID will be
660 long keyctl_keyring_search(key_serial_t ringid,
661 const char __user *_type,
662 const char __user *_description,
663 key_serial_t destringid)
665 struct key_type *ktype;
666 key_ref_t keyring_ref, key_ref, dest_ref;
667 char type[32], *description;
670 /* pull the type and description into kernel space */
671 ret = key_get_type_from_user(type, _type, sizeof(type));
675 description = strndup_user(_description, KEY_MAX_DESC_SIZE);
676 if (IS_ERR(description)) {
677 ret = PTR_ERR(description);
681 /* get the keyring at which to begin the search */
682 keyring_ref = lookup_user_key(ringid, 0, KEY_NEED_SEARCH);
683 if (IS_ERR(keyring_ref)) {
684 ret = PTR_ERR(keyring_ref);
688 /* get the destination keyring if specified */
691 dest_ref = lookup_user_key(destringid, KEY_LOOKUP_CREATE,
693 if (IS_ERR(dest_ref)) {
694 ret = PTR_ERR(dest_ref);
699 /* find the key type */
700 ktype = key_type_lookup(type);
702 ret = PTR_ERR(ktype);
707 key_ref = keyring_search(keyring_ref, ktype, description);
708 if (IS_ERR(key_ref)) {
709 ret = PTR_ERR(key_ref);
711 /* treat lack or presence of a negative key the same */
717 /* link the resulting key to the destination keyring if we can */
719 ret = key_permission(key_ref, KEY_NEED_LINK);
723 ret = key_link(key_ref_to_ptr(dest_ref), key_ref_to_ptr(key_ref));
728 ret = key_ref_to_ptr(key_ref)->serial;
731 key_ref_put(key_ref);
735 key_ref_put(dest_ref);
737 key_ref_put(keyring_ref);
745 * Read a key's payload.
747 * The key must either grant the caller Read permission, or it must grant the
748 * caller Search permission when searched for from the process keyrings.
750 * If successful, we place up to buflen bytes of data into the buffer, if one
751 * is provided, and return the amount of data that is available in the key,
752 * irrespective of how much we copied into the buffer.
754 long keyctl_read_key(key_serial_t keyid, char __user *buffer, size_t buflen)
760 /* find the key first */
761 key_ref = lookup_user_key(keyid, 0, 0);
762 if (IS_ERR(key_ref)) {
767 key = key_ref_to_ptr(key_ref);
769 /* see if we can read it directly */
770 ret = key_permission(key_ref, KEY_NEED_READ);
776 /* we can't; see if it's searchable from this process's keyrings
777 * - we automatically take account of the fact that it may be
778 * dangling off an instantiation key
780 if (!is_key_possessed(key_ref)) {
785 /* the key is probably readable - now try to read it */
788 if (key->type->read) {
789 /* Read the data with the semaphore held (since we might sleep)
790 * to protect against the key being updated or revoked.
792 down_read(&key->sem);
793 ret = key_validate(key);
795 ret = key->type->read(key, buffer, buflen);
806 * Change the ownership of a key
808 * The key must grant the caller Setattr permission for this to work, though
809 * the key need not be fully instantiated yet. For the UID to be changed, or
810 * for the GID to be changed to a group the caller is not a member of, the
811 * caller must have sysadmin capability. If either uid or gid is -1 then that
812 * attribute is not changed.
814 * If the UID is to be changed, the new user must have sufficient quota to
815 * accept the key. The quota deduction will be removed from the old user to
816 * the new user should the attribute be changed.
818 * If successful, 0 will be returned.
820 long keyctl_chown_key(key_serial_t id, uid_t user, gid_t group)
822 struct key_user *newowner, *zapowner = NULL;
829 uid = make_kuid(current_user_ns(), user);
830 gid = make_kgid(current_user_ns(), group);
832 if ((user != (uid_t) -1) && !uid_valid(uid))
834 if ((group != (gid_t) -1) && !gid_valid(gid))
838 if (user == (uid_t) -1 && group == (gid_t) -1)
841 key_ref = lookup_user_key(id, KEY_LOOKUP_CREATE | KEY_LOOKUP_PARTIAL,
843 if (IS_ERR(key_ref)) {
844 ret = PTR_ERR(key_ref);
848 key = key_ref_to_ptr(key_ref);
850 /* make the changes with the locks held to prevent chown/chown races */
852 down_write(&key->sem);
854 if (!capable(CAP_SYS_ADMIN)) {
855 /* only the sysadmin can chown a key to some other UID */
856 if (user != (uid_t) -1 && !uid_eq(key->uid, uid))
859 /* only the sysadmin can set the key's GID to a group other
860 * than one of those that the current process subscribes to */
861 if (group != (gid_t) -1 && !gid_eq(gid, key->gid) && !in_group_p(gid))
866 if (user != (uid_t) -1 && !uid_eq(uid, key->uid)) {
868 newowner = key_user_lookup(uid);
872 /* transfer the quota burden to the new user */
873 if (test_bit(KEY_FLAG_IN_QUOTA, &key->flags)) {
874 unsigned maxkeys = uid_eq(uid, GLOBAL_ROOT_UID) ?
875 key_quota_root_maxkeys : key_quota_maxkeys;
876 unsigned maxbytes = uid_eq(uid, GLOBAL_ROOT_UID) ?
877 key_quota_root_maxbytes : key_quota_maxbytes;
879 spin_lock(&newowner->lock);
880 if (newowner->qnkeys + 1 >= maxkeys ||
881 newowner->qnbytes + key->quotalen >= maxbytes ||
882 newowner->qnbytes + key->quotalen <
887 newowner->qnbytes += key->quotalen;
888 spin_unlock(&newowner->lock);
890 spin_lock(&key->user->lock);
892 key->user->qnbytes -= key->quotalen;
893 spin_unlock(&key->user->lock);
896 atomic_dec(&key->user->nkeys);
897 atomic_inc(&newowner->nkeys);
899 if (test_bit(KEY_FLAG_INSTANTIATED, &key->flags)) {
900 atomic_dec(&key->user->nikeys);
901 atomic_inc(&newowner->nikeys);
904 zapowner = key->user;
905 key->user = newowner;
910 if (group != (gid_t) -1)
919 key_user_put(zapowner);
924 spin_unlock(&newowner->lock);
931 * Change the permission mask on a key.
933 * The key must grant the caller Setattr permission for this to work, though
934 * the key need not be fully instantiated yet. If the caller does not have
935 * sysadmin capability, it may only change the permission on keys that it owns.
937 long keyctl_setperm_key(key_serial_t id, key_perm_t perm)
944 if (perm & ~(KEY_POS_ALL | KEY_USR_ALL | KEY_GRP_ALL | KEY_OTH_ALL))
947 key_ref = lookup_user_key(id, KEY_LOOKUP_CREATE | KEY_LOOKUP_PARTIAL,
949 if (IS_ERR(key_ref)) {
950 ret = PTR_ERR(key_ref);
954 key = key_ref_to_ptr(key_ref);
956 /* make the changes with the locks held to prevent chown/chmod races */
958 down_write(&key->sem);
960 /* if we're not the sysadmin, we can only change a key that we own */
961 if (capable(CAP_SYS_ADMIN) || uid_eq(key->uid, current_fsuid())) {
973 * Get the destination keyring for instantiation and check that the caller has
974 * Write permission on it.
976 static long get_instantiation_keyring(key_serial_t ringid,
977 struct request_key_auth *rka,
978 struct key **_dest_keyring)
982 *_dest_keyring = NULL;
984 /* just return a NULL pointer if we weren't asked to make a link */
988 /* if a specific keyring is nominated by ID, then use that */
990 dkref = lookup_user_key(ringid, KEY_LOOKUP_CREATE, KEY_NEED_WRITE);
992 return PTR_ERR(dkref);
993 *_dest_keyring = key_ref_to_ptr(dkref);
997 if (ringid == KEY_SPEC_REQKEY_AUTH_KEY)
1000 /* otherwise specify the destination keyring recorded in the
1001 * authorisation key (any KEY_SPEC_*_KEYRING) */
1002 if (ringid >= KEY_SPEC_REQUESTOR_KEYRING) {
1003 *_dest_keyring = key_get(rka->dest_keyring);
1011 * Change the request_key authorisation key on the current process.
1013 static int keyctl_change_reqkey_auth(struct key *key)
1017 new = prepare_creds();
1021 key_put(new->request_key_auth);
1022 new->request_key_auth = key_get(key);
1024 return commit_creds(new);
1028 * Instantiate a key with the specified payload and link the key into the
1029 * destination keyring if one is given.
1031 * The caller must have the appropriate instantiation permit set for this to
1032 * work (see keyctl_assume_authority). No other permissions are required.
1034 * If successful, 0 will be returned.
1036 long keyctl_instantiate_key_common(key_serial_t id,
1037 struct iov_iter *from,
1038 key_serial_t ringid)
1040 const struct cred *cred = current_cred();
1041 struct request_key_auth *rka;
1042 struct key *instkey, *dest_keyring;
1043 size_t plen = from ? iov_iter_count(from) : 0;
1047 kenter("%d,,%zu,%d", id, plen, ringid);
1053 if (plen > 1024 * 1024 - 1)
1056 /* the appropriate instantiation authorisation key must have been
1057 * assumed before calling this */
1059 instkey = cred->request_key_auth;
1063 rka = instkey->payload.data[0];
1064 if (rka->target_key->serial != id)
1067 /* pull the payload in if one was supplied */
1072 payload = kvmalloc(plen, GFP_KERNEL);
1077 if (!copy_from_iter_full(payload, plen, from))
1081 /* find the destination keyring amongst those belonging to the
1082 * requesting task */
1083 ret = get_instantiation_keyring(ringid, rka, &dest_keyring);
1087 /* instantiate the key and link it into a keyring */
1088 ret = key_instantiate_and_link(rka->target_key, payload, plen,
1089 dest_keyring, instkey);
1091 key_put(dest_keyring);
1093 /* discard the assumed authority if it's just been disabled by
1094 * instantiation of the key */
1096 keyctl_change_reqkey_auth(NULL);
1100 memzero_explicit(payload, plen);
1108 * Instantiate a key with the specified payload and link the key into the
1109 * destination keyring if one is given.
1111 * The caller must have the appropriate instantiation permit set for this to
1112 * work (see keyctl_assume_authority). No other permissions are required.
1114 * If successful, 0 will be returned.
1116 long keyctl_instantiate_key(key_serial_t id,
1117 const void __user *_payload,
1119 key_serial_t ringid)
1121 if (_payload && plen) {
1123 struct iov_iter from;
1126 ret = import_single_range(WRITE, (void __user *)_payload, plen,
1131 return keyctl_instantiate_key_common(id, &from, ringid);
1134 return keyctl_instantiate_key_common(id, NULL, ringid);
1138 * Instantiate a key with the specified multipart payload and link the key into
1139 * the destination keyring if one is given.
1141 * The caller must have the appropriate instantiation permit set for this to
1142 * work (see keyctl_assume_authority). No other permissions are required.
1144 * If successful, 0 will be returned.
1146 long keyctl_instantiate_key_iov(key_serial_t id,
1147 const struct iovec __user *_payload_iov,
1149 key_serial_t ringid)
1151 struct iovec iovstack[UIO_FASTIOV], *iov = iovstack;
1152 struct iov_iter from;
1158 ret = import_iovec(WRITE, _payload_iov, ioc,
1159 ARRAY_SIZE(iovstack), &iov, &from);
1162 ret = keyctl_instantiate_key_common(id, &from, ringid);
1168 * Negatively instantiate the key with the given timeout (in seconds) and link
1169 * the key into the destination keyring if one is given.
1171 * The caller must have the appropriate instantiation permit set for this to
1172 * work (see keyctl_assume_authority). No other permissions are required.
1174 * The key and any links to the key will be automatically garbage collected
1175 * after the timeout expires.
1177 * Negative keys are used to rate limit repeated request_key() calls by causing
1178 * them to return -ENOKEY until the negative key expires.
1180 * If successful, 0 will be returned.
1182 long keyctl_negate_key(key_serial_t id, unsigned timeout, key_serial_t ringid)
1184 return keyctl_reject_key(id, timeout, ENOKEY, ringid);
1188 * Negatively instantiate the key with the given timeout (in seconds) and error
1189 * code and link the key into the destination keyring if one is given.
1191 * The caller must have the appropriate instantiation permit set for this to
1192 * work (see keyctl_assume_authority). No other permissions are required.
1194 * The key and any links to the key will be automatically garbage collected
1195 * after the timeout expires.
1197 * Negative keys are used to rate limit repeated request_key() calls by causing
1198 * them to return the specified error code until the negative key expires.
1200 * If successful, 0 will be returned.
1202 long keyctl_reject_key(key_serial_t id, unsigned timeout, unsigned error,
1203 key_serial_t ringid)
1205 const struct cred *cred = current_cred();
1206 struct request_key_auth *rka;
1207 struct key *instkey, *dest_keyring;
1210 kenter("%d,%u,%u,%d", id, timeout, error, ringid);
1212 /* must be a valid error code and mustn't be a kernel special */
1214 error >= MAX_ERRNO ||
1215 error == ERESTARTSYS ||
1216 error == ERESTARTNOINTR ||
1217 error == ERESTARTNOHAND ||
1218 error == ERESTART_RESTARTBLOCK)
1221 /* the appropriate instantiation authorisation key must have been
1222 * assumed before calling this */
1224 instkey = cred->request_key_auth;
1228 rka = instkey->payload.data[0];
1229 if (rka->target_key->serial != id)
1232 /* find the destination keyring if present (which must also be
1234 ret = get_instantiation_keyring(ringid, rka, &dest_keyring);
1238 /* instantiate the key and link it into a keyring */
1239 ret = key_reject_and_link(rka->target_key, timeout, error,
1240 dest_keyring, instkey);
1242 key_put(dest_keyring);
1244 /* discard the assumed authority if it's just been disabled by
1245 * instantiation of the key */
1247 keyctl_change_reqkey_auth(NULL);
1254 * Read or set the default keyring in which request_key() will cache keys and
1255 * return the old setting.
1257 * If a thread or process keyring is specified then it will be created if it
1258 * doesn't yet exist. The old setting will be returned if successful.
1260 long keyctl_set_reqkey_keyring(int reqkey_defl)
1263 int ret, old_setting;
1265 old_setting = current_cred_xxx(jit_keyring);
1267 if (reqkey_defl == KEY_REQKEY_DEFL_NO_CHANGE)
1270 new = prepare_creds();
1274 switch (reqkey_defl) {
1275 case KEY_REQKEY_DEFL_THREAD_KEYRING:
1276 ret = install_thread_keyring_to_cred(new);
1281 case KEY_REQKEY_DEFL_PROCESS_KEYRING:
1282 ret = install_process_keyring_to_cred(new);
1287 case KEY_REQKEY_DEFL_DEFAULT:
1288 case KEY_REQKEY_DEFL_SESSION_KEYRING:
1289 case KEY_REQKEY_DEFL_USER_KEYRING:
1290 case KEY_REQKEY_DEFL_USER_SESSION_KEYRING:
1291 case KEY_REQKEY_DEFL_REQUESTOR_KEYRING:
1294 case KEY_REQKEY_DEFL_NO_CHANGE:
1295 case KEY_REQKEY_DEFL_GROUP_KEYRING:
1302 new->jit_keyring = reqkey_defl;
1311 * Set or clear the timeout on a key.
1313 * Either the key must grant the caller Setattr permission or else the caller
1314 * must hold an instantiation authorisation token for the key.
1316 * The timeout is either 0 to clear the timeout, or a number of seconds from
1317 * the current time. The key and any links to the key will be automatically
1318 * garbage collected after the timeout expires.
1320 * Keys with KEY_FLAG_KEEP set should not be timed out.
1322 * If successful, 0 is returned.
1324 long keyctl_set_timeout(key_serial_t id, unsigned timeout)
1326 struct key *key, *instkey;
1330 key_ref = lookup_user_key(id, KEY_LOOKUP_CREATE | KEY_LOOKUP_PARTIAL,
1332 if (IS_ERR(key_ref)) {
1333 /* setting the timeout on a key under construction is permitted
1334 * if we have the authorisation token handy */
1335 if (PTR_ERR(key_ref) == -EACCES) {
1336 instkey = key_get_instantiation_authkey(id);
1337 if (!IS_ERR(instkey)) {
1339 key_ref = lookup_user_key(id,
1342 if (!IS_ERR(key_ref))
1347 ret = PTR_ERR(key_ref);
1352 key = key_ref_to_ptr(key_ref);
1354 if (test_bit(KEY_FLAG_KEEP, &key->flags))
1357 key_set_timeout(key, timeout);
1365 * Assume (or clear) the authority to instantiate the specified key.
1367 * This sets the authoritative token currently in force for key instantiation.
1368 * This must be done for a key to be instantiated. It has the effect of making
1369 * available all the keys from the caller of the request_key() that created a
1370 * key to request_key() calls made by the caller of this function.
1372 * The caller must have the instantiation key in their process keyrings with a
1373 * Search permission grant available to the caller.
1375 * If the ID given is 0, then the setting will be cleared and 0 returned.
1377 * If the ID given has a matching an authorisation key, then that key will be
1378 * set and its ID will be returned. The authorisation key can be read to get
1379 * the callout information passed to request_key().
1381 long keyctl_assume_authority(key_serial_t id)
1383 struct key *authkey;
1386 /* special key IDs aren't permitted */
1391 /* we divest ourselves of authority if given an ID of 0 */
1393 ret = keyctl_change_reqkey_auth(NULL);
1397 /* attempt to assume the authority temporarily granted to us whilst we
1398 * instantiate the specified key
1399 * - the authorisation key must be in the current task's keyrings
1402 authkey = key_get_instantiation_authkey(id);
1403 if (IS_ERR(authkey)) {
1404 ret = PTR_ERR(authkey);
1408 ret = keyctl_change_reqkey_auth(authkey);
1413 ret = authkey->serial;
1419 * Get a key's the LSM security label.
1421 * The key must grant the caller View permission for this to work.
1423 * If there's a buffer, then up to buflen bytes of data will be placed into it.
1425 * If successful, the amount of information available will be returned,
1426 * irrespective of how much was copied (including the terminal NUL).
1428 long keyctl_get_security(key_serial_t keyid,
1429 char __user *buffer,
1432 struct key *key, *instkey;
1437 key_ref = lookup_user_key(keyid, KEY_LOOKUP_PARTIAL, KEY_NEED_VIEW);
1438 if (IS_ERR(key_ref)) {
1439 if (PTR_ERR(key_ref) != -EACCES)
1440 return PTR_ERR(key_ref);
1442 /* viewing a key under construction is also permitted if we
1443 * have the authorisation token handy */
1444 instkey = key_get_instantiation_authkey(keyid);
1445 if (IS_ERR(instkey))
1446 return PTR_ERR(instkey);
1449 key_ref = lookup_user_key(keyid, KEY_LOOKUP_PARTIAL, 0);
1450 if (IS_ERR(key_ref))
1451 return PTR_ERR(key_ref);
1454 key = key_ref_to_ptr(key_ref);
1455 ret = security_key_getsecurity(key, &context);
1457 /* if no information was returned, give userspace an empty
1460 if (buffer && buflen > 0 &&
1461 copy_to_user(buffer, "", 1) != 0)
1463 } else if (ret > 0) {
1464 /* return as much data as there's room for */
1465 if (buffer && buflen > 0) {
1469 if (copy_to_user(buffer, context, buflen) != 0)
1476 key_ref_put(key_ref);
1481 * Attempt to install the calling process's session keyring on the process's
1484 * The keyring must exist and must grant the caller LINK permission, and the
1485 * parent process must be single-threaded and must have the same effective
1486 * ownership as this process and mustn't be SUID/SGID.
1488 * The keyring will be emplaced on the parent when it next resumes userspace.
1490 * If successful, 0 will be returned.
1492 long keyctl_session_to_parent(void)
1494 struct task_struct *me, *parent;
1495 const struct cred *mycred, *pcred;
1496 struct callback_head *newwork, *oldwork;
1497 key_ref_t keyring_r;
1501 keyring_r = lookup_user_key(KEY_SPEC_SESSION_KEYRING, 0, KEY_NEED_LINK);
1502 if (IS_ERR(keyring_r))
1503 return PTR_ERR(keyring_r);
1507 /* our parent is going to need a new cred struct, a new tgcred struct
1508 * and new security data, so we allocate them here to prevent ENOMEM in
1510 cred = cred_alloc_blank();
1513 newwork = &cred->rcu;
1515 cred->session_keyring = key_ref_to_ptr(keyring_r);
1517 init_task_work(newwork, key_change_session_keyring);
1521 write_lock_irq(&tasklist_lock);
1525 parent = me->real_parent;
1527 /* the parent mustn't be init and mustn't be a kernel thread */
1528 if (parent->pid <= 1 || !parent->mm)
1531 /* the parent must be single threaded */
1532 if (!thread_group_empty(parent))
1535 /* the parent and the child must have different session keyrings or
1536 * there's no point */
1537 mycred = current_cred();
1538 pcred = __task_cred(parent);
1539 if (mycred == pcred ||
1540 mycred->session_keyring == pcred->session_keyring) {
1545 /* the parent must have the same effective ownership and mustn't be
1547 if (!uid_eq(pcred->uid, mycred->euid) ||
1548 !uid_eq(pcred->euid, mycred->euid) ||
1549 !uid_eq(pcred->suid, mycred->euid) ||
1550 !gid_eq(pcred->gid, mycred->egid) ||
1551 !gid_eq(pcred->egid, mycred->egid) ||
1552 !gid_eq(pcred->sgid, mycred->egid))
1555 /* the keyrings must have the same UID */
1556 if ((pcred->session_keyring &&
1557 !uid_eq(pcred->session_keyring->uid, mycred->euid)) ||
1558 !uid_eq(mycred->session_keyring->uid, mycred->euid))
1561 /* cancel an already pending keyring replacement */
1562 oldwork = task_work_cancel(parent, key_change_session_keyring);
1564 /* the replacement session keyring is applied just prior to userspace
1566 ret = task_work_add(parent, newwork, true);
1570 write_unlock_irq(&tasklist_lock);
1573 put_cred(container_of(oldwork, struct cred, rcu));
1579 key_ref_put(keyring_r);
1584 * Apply a restriction to a given keyring.
1586 * The caller must have Setattr permission to change keyring restrictions.
1588 * The requested type name may be a NULL pointer to reject all attempts
1589 * to link to the keyring. If _type is non-NULL, _restriction can be
1590 * NULL or a pointer to a string describing the restriction. If _type is
1591 * NULL, _restriction must also be NULL.
1593 * Returns 0 if successful.
1595 long keyctl_restrict_keyring(key_serial_t id, const char __user *_type,
1596 const char __user *_restriction)
1599 bool link_reject = !_type;
1601 char *restriction = NULL;
1604 key_ref = lookup_user_key(id, 0, KEY_NEED_SETATTR);
1605 if (IS_ERR(key_ref))
1606 return PTR_ERR(key_ref);
1609 ret = key_get_type_from_user(type, _type, sizeof(type));
1620 restriction = strndup_user(_restriction, PAGE_SIZE);
1621 if (IS_ERR(restriction)) {
1622 ret = PTR_ERR(restriction);
1627 ret = keyring_restrict(key_ref, link_reject ? NULL : type, restriction);
1631 key_ref_put(key_ref);
1637 * The key control system call
1639 SYSCALL_DEFINE5(keyctl, int, option, unsigned long, arg2, unsigned long, arg3,
1640 unsigned long, arg4, unsigned long, arg5)
1643 case KEYCTL_GET_KEYRING_ID:
1644 return keyctl_get_keyring_ID((key_serial_t) arg2,
1647 case KEYCTL_JOIN_SESSION_KEYRING:
1648 return keyctl_join_session_keyring((const char __user *) arg2);
1651 return keyctl_update_key((key_serial_t) arg2,
1652 (const void __user *) arg3,
1656 return keyctl_revoke_key((key_serial_t) arg2);
1658 case KEYCTL_DESCRIBE:
1659 return keyctl_describe_key((key_serial_t) arg2,
1660 (char __user *) arg3,
1664 return keyctl_keyring_clear((key_serial_t) arg2);
1667 return keyctl_keyring_link((key_serial_t) arg2,
1668 (key_serial_t) arg3);
1671 return keyctl_keyring_unlink((key_serial_t) arg2,
1672 (key_serial_t) arg3);
1675 return keyctl_keyring_search((key_serial_t) arg2,
1676 (const char __user *) arg3,
1677 (const char __user *) arg4,
1678 (key_serial_t) arg5);
1681 return keyctl_read_key((key_serial_t) arg2,
1682 (char __user *) arg3,
1686 return keyctl_chown_key((key_serial_t) arg2,
1690 case KEYCTL_SETPERM:
1691 return keyctl_setperm_key((key_serial_t) arg2,
1694 case KEYCTL_INSTANTIATE:
1695 return keyctl_instantiate_key((key_serial_t) arg2,
1696 (const void __user *) arg3,
1698 (key_serial_t) arg5);
1701 return keyctl_negate_key((key_serial_t) arg2,
1703 (key_serial_t) arg4);
1705 case KEYCTL_SET_REQKEY_KEYRING:
1706 return keyctl_set_reqkey_keyring(arg2);
1708 case KEYCTL_SET_TIMEOUT:
1709 return keyctl_set_timeout((key_serial_t) arg2,
1712 case KEYCTL_ASSUME_AUTHORITY:
1713 return keyctl_assume_authority((key_serial_t) arg2);
1715 case KEYCTL_GET_SECURITY:
1716 return keyctl_get_security((key_serial_t) arg2,
1717 (char __user *) arg3,
1720 case KEYCTL_SESSION_TO_PARENT:
1721 return keyctl_session_to_parent();
1724 return keyctl_reject_key((key_serial_t) arg2,
1727 (key_serial_t) arg5);
1729 case KEYCTL_INSTANTIATE_IOV:
1730 return keyctl_instantiate_key_iov(
1731 (key_serial_t) arg2,
1732 (const struct iovec __user *) arg3,
1734 (key_serial_t) arg5);
1736 case KEYCTL_INVALIDATE:
1737 return keyctl_invalidate_key((key_serial_t) arg2);
1739 case KEYCTL_GET_PERSISTENT:
1740 return keyctl_get_persistent((uid_t)arg2, (key_serial_t)arg3);
1742 case KEYCTL_DH_COMPUTE:
1743 return keyctl_dh_compute((struct keyctl_dh_params __user *) arg2,
1744 (char __user *) arg3, (size_t) arg4,
1745 (struct keyctl_kdf_params __user *) arg5);
1747 case KEYCTL_RESTRICT_KEYRING:
1748 return keyctl_restrict_keyring((key_serial_t) arg2,
1749 (const char __user *) arg3,
1750 (const char __user *) arg4);