1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /* Userspace key control operations
4 * Copyright (C) 2004-5 Red Hat, Inc. All Rights Reserved.
5 * Written by David Howells (dhowells@redhat.com)
8 #include <linux/init.h>
9 #include <linux/sched.h>
10 #include <linux/sched/task.h>
11 #include <linux/slab.h>
12 #include <linux/syscalls.h>
13 #include <linux/key.h>
14 #include <linux/keyctl.h>
16 #include <linux/capability.h>
17 #include <linux/cred.h>
18 #include <linux/string.h>
19 #include <linux/err.h>
20 #include <linux/vmalloc.h>
21 #include <linux/security.h>
22 #include <linux/uio.h>
23 #include <linux/uaccess.h>
24 #include <keys/request_key_auth-type.h>
27 #define KEY_MAX_DESC_SIZE 4096
29 static int key_get_type_from_user(char *type,
30 const char __user *_type,
35 ret = strncpy_from_user(type, _type, len);
38 if (ret == 0 || ret >= len)
47 * Extract the description of a new key from userspace and either add it as a
48 * new key to the specified keyring or update a matching key in that keyring.
50 * If the description is NULL or an empty string, the key type is asked to
51 * generate one from the payload.
53 * The keyring must be writable so that we can attach the key to it.
55 * If successful, the new key's serial number is returned, otherwise an error
58 SYSCALL_DEFINE5(add_key, const char __user *, _type,
59 const char __user *, _description,
60 const void __user *, _payload,
64 key_ref_t keyring_ref, key_ref;
65 char type[32], *description;
70 if (plen > 1024 * 1024 - 1)
73 /* draw all the data into kernel space */
74 ret = key_get_type_from_user(type, _type, sizeof(type));
80 description = strndup_user(_description, KEY_MAX_DESC_SIZE);
81 if (IS_ERR(description)) {
82 ret = PTR_ERR(description);
88 } else if ((description[0] == '.') &&
89 (strncmp(type, "keyring", 7) == 0)) {
95 /* pull the payload in if one was supplied */
100 payload = kvmalloc(plen, GFP_KERNEL);
105 if (copy_from_user(payload, _payload, plen) != 0)
109 /* find the target keyring (which must be writable) */
110 keyring_ref = lookup_user_key(ringid, KEY_LOOKUP_CREATE, KEY_NEED_WRITE);
111 if (IS_ERR(keyring_ref)) {
112 ret = PTR_ERR(keyring_ref);
116 /* create or update the requested key and add it to the target
118 key_ref = key_create_or_update(keyring_ref, type, description,
119 payload, plen, KEY_PERM_UNDEF,
121 if (!IS_ERR(key_ref)) {
122 ret = key_ref_to_ptr(key_ref)->serial;
123 key_ref_put(key_ref);
126 ret = PTR_ERR(key_ref);
129 key_ref_put(keyring_ref);
132 memzero_explicit(payload, plen);
142 * Search the process keyrings and keyring trees linked from those for a
143 * matching key. Keyrings must have appropriate Search permission to be
146 * If a key is found, it will be attached to the destination keyring if there's
147 * one specified and the serial number of the key will be returned.
149 * If no key is found, /sbin/request-key will be invoked if _callout_info is
150 * non-NULL in an attempt to create a key. The _callout_info string will be
151 * passed to /sbin/request-key to aid with completing the request. If the
152 * _callout_info string is "" then it will be changed to "-".
154 SYSCALL_DEFINE4(request_key, const char __user *, _type,
155 const char __user *, _description,
156 const char __user *, _callout_info,
157 key_serial_t, destringid)
159 struct key_type *ktype;
163 char type[32], *description, *callout_info;
166 /* pull the type into kernel space */
167 ret = key_get_type_from_user(type, _type, sizeof(type));
171 /* pull the description into kernel space */
172 description = strndup_user(_description, KEY_MAX_DESC_SIZE);
173 if (IS_ERR(description)) {
174 ret = PTR_ERR(description);
178 /* pull the callout info into kernel space */
182 callout_info = strndup_user(_callout_info, PAGE_SIZE);
183 if (IS_ERR(callout_info)) {
184 ret = PTR_ERR(callout_info);
187 callout_len = strlen(callout_info);
190 /* get the destination keyring if specified */
193 dest_ref = lookup_user_key(destringid, KEY_LOOKUP_CREATE,
195 if (IS_ERR(dest_ref)) {
196 ret = PTR_ERR(dest_ref);
201 /* find the key type */
202 ktype = key_type_lookup(type);
204 ret = PTR_ERR(ktype);
209 key = request_key_and_link(ktype, description, callout_info,
210 callout_len, NULL, key_ref_to_ptr(dest_ref),
217 /* wait for the key to finish being constructed */
218 ret = wait_for_key_construction(key, 1);
229 key_ref_put(dest_ref);
239 * Get the ID of the specified process keyring.
241 * The requested keyring must have search permission to be found.
243 * If successful, the ID of the requested keyring will be returned.
245 long keyctl_get_keyring_ID(key_serial_t id, int create)
248 unsigned long lflags;
251 lflags = create ? KEY_LOOKUP_CREATE : 0;
252 key_ref = lookup_user_key(id, lflags, KEY_NEED_SEARCH);
253 if (IS_ERR(key_ref)) {
254 ret = PTR_ERR(key_ref);
258 ret = key_ref_to_ptr(key_ref)->serial;
259 key_ref_put(key_ref);
265 * Join a (named) session keyring.
267 * Create and join an anonymous session keyring or join a named session
268 * keyring, creating it if necessary. A named session keyring must have Search
269 * permission for it to be joined. Session keyrings without this permit will
270 * be skipped over. It is not permitted for userspace to create or join
271 * keyrings whose name begin with a dot.
273 * If successful, the ID of the joined session keyring will be returned.
275 long keyctl_join_session_keyring(const char __user *_name)
280 /* fetch the name from userspace */
283 name = strndup_user(_name, KEY_MAX_DESC_SIZE);
294 /* join the session */
295 ret = join_session_keyring(name);
303 * Update a key's data payload from the given data.
305 * The key must grant the caller Write permission and the key type must support
306 * updating for this to work. A negative key can be positively instantiated
309 * If successful, 0 will be returned. If the key type does not support
310 * updating, then -EOPNOTSUPP will be returned.
312 long keyctl_update_key(key_serial_t id,
313 const void __user *_payload,
321 if (plen > PAGE_SIZE)
324 /* pull the payload in if one was supplied */
328 payload = kmalloc(plen, GFP_KERNEL);
333 if (copy_from_user(payload, _payload, plen) != 0)
337 /* find the target key (which must be writable) */
338 key_ref = lookup_user_key(id, 0, KEY_NEED_WRITE);
339 if (IS_ERR(key_ref)) {
340 ret = PTR_ERR(key_ref);
345 ret = key_update(key_ref, payload, plen);
347 key_ref_put(key_ref);
357 * The key must be grant the caller Write or Setattr permission for this to
358 * work. The key type should give up its quota claim when revoked. The key
359 * and any links to the key will be automatically garbage collected after a
360 * certain amount of time (/proc/sys/kernel/keys/gc_delay).
362 * Keys with KEY_FLAG_KEEP set should not be revoked.
364 * If successful, 0 is returned.
366 long keyctl_revoke_key(key_serial_t id)
372 key_ref = lookup_user_key(id, 0, KEY_NEED_WRITE);
373 if (IS_ERR(key_ref)) {
374 ret = PTR_ERR(key_ref);
377 key_ref = lookup_user_key(id, 0, KEY_NEED_SETATTR);
378 if (IS_ERR(key_ref)) {
379 ret = PTR_ERR(key_ref);
384 key = key_ref_to_ptr(key_ref);
386 if (test_bit(KEY_FLAG_KEEP, &key->flags))
391 key_ref_put(key_ref);
399 * The key must be grant the caller Invalidate permission for this to work.
400 * The key and any links to the key will be automatically garbage collected
403 * Keys with KEY_FLAG_KEEP set should not be invalidated.
405 * If successful, 0 is returned.
407 long keyctl_invalidate_key(key_serial_t id)
415 key_ref = lookup_user_key(id, 0, KEY_NEED_SEARCH);
416 if (IS_ERR(key_ref)) {
417 ret = PTR_ERR(key_ref);
419 /* Root is permitted to invalidate certain special keys */
420 if (capable(CAP_SYS_ADMIN)) {
421 key_ref = lookup_user_key(id, 0, 0);
424 if (test_bit(KEY_FLAG_ROOT_CAN_INVAL,
425 &key_ref_to_ptr(key_ref)->flags))
434 key = key_ref_to_ptr(key_ref);
436 if (test_bit(KEY_FLAG_KEEP, &key->flags))
441 key_ref_put(key_ref);
443 kleave(" = %ld", ret);
448 * Clear the specified keyring, creating an empty process keyring if one of the
449 * special keyring IDs is used.
451 * The keyring must grant the caller Write permission and not have
452 * KEY_FLAG_KEEP set for this to work. If successful, 0 will be returned.
454 long keyctl_keyring_clear(key_serial_t ringid)
456 key_ref_t keyring_ref;
460 keyring_ref = lookup_user_key(ringid, KEY_LOOKUP_CREATE, KEY_NEED_WRITE);
461 if (IS_ERR(keyring_ref)) {
462 ret = PTR_ERR(keyring_ref);
464 /* Root is permitted to invalidate certain special keyrings */
465 if (capable(CAP_SYS_ADMIN)) {
466 keyring_ref = lookup_user_key(ringid, 0, 0);
467 if (IS_ERR(keyring_ref))
469 if (test_bit(KEY_FLAG_ROOT_CAN_CLEAR,
470 &key_ref_to_ptr(keyring_ref)->flags))
479 keyring = key_ref_to_ptr(keyring_ref);
480 if (test_bit(KEY_FLAG_KEEP, &keyring->flags))
483 ret = keyring_clear(keyring);
485 key_ref_put(keyring_ref);
491 * Create a link from a keyring to a key if there's no matching key in the
492 * keyring, otherwise replace the link to the matching key with a link to the
495 * The key must grant the caller Link permission and the the keyring must grant
496 * the caller Write permission. Furthermore, if an additional link is created,
497 * the keyring's quota will be extended.
499 * If successful, 0 will be returned.
501 long keyctl_keyring_link(key_serial_t id, key_serial_t ringid)
503 key_ref_t keyring_ref, key_ref;
506 keyring_ref = lookup_user_key(ringid, KEY_LOOKUP_CREATE, KEY_NEED_WRITE);
507 if (IS_ERR(keyring_ref)) {
508 ret = PTR_ERR(keyring_ref);
512 key_ref = lookup_user_key(id, KEY_LOOKUP_CREATE, KEY_NEED_LINK);
513 if (IS_ERR(key_ref)) {
514 ret = PTR_ERR(key_ref);
518 ret = key_link(key_ref_to_ptr(keyring_ref), key_ref_to_ptr(key_ref));
520 key_ref_put(key_ref);
522 key_ref_put(keyring_ref);
528 * Unlink a key from a keyring.
530 * The keyring must grant the caller Write permission for this to work; the key
531 * itself need not grant the caller anything. If the last link to a key is
532 * removed then that key will be scheduled for destruction.
534 * Keys or keyrings with KEY_FLAG_KEEP set should not be unlinked.
536 * If successful, 0 will be returned.
538 long keyctl_keyring_unlink(key_serial_t id, key_serial_t ringid)
540 key_ref_t keyring_ref, key_ref;
541 struct key *keyring, *key;
544 keyring_ref = lookup_user_key(ringid, 0, KEY_NEED_WRITE);
545 if (IS_ERR(keyring_ref)) {
546 ret = PTR_ERR(keyring_ref);
550 key_ref = lookup_user_key(id, KEY_LOOKUP_FOR_UNLINK, 0);
551 if (IS_ERR(key_ref)) {
552 ret = PTR_ERR(key_ref);
556 keyring = key_ref_to_ptr(keyring_ref);
557 key = key_ref_to_ptr(key_ref);
558 if (test_bit(KEY_FLAG_KEEP, &keyring->flags) &&
559 test_bit(KEY_FLAG_KEEP, &key->flags))
562 ret = key_unlink(keyring, key);
564 key_ref_put(key_ref);
566 key_ref_put(keyring_ref);
572 * Return a description of a key to userspace.
574 * The key must grant the caller View permission for this to work.
576 * If there's a buffer, we place up to buflen bytes of data into it formatted
577 * in the following way:
579 * type;uid;gid;perm;description<NUL>
581 * If successful, we return the amount of description available, irrespective
582 * of how much we may have copied into the buffer.
584 long keyctl_describe_key(key_serial_t keyid,
588 struct key *key, *instkey;
592 int desclen, infolen;
594 key_ref = lookup_user_key(keyid, KEY_LOOKUP_PARTIAL, KEY_NEED_VIEW);
595 if (IS_ERR(key_ref)) {
596 /* viewing a key under construction is permitted if we have the
597 * authorisation token handy */
598 if (PTR_ERR(key_ref) == -EACCES) {
599 instkey = key_get_instantiation_authkey(keyid);
600 if (!IS_ERR(instkey)) {
602 key_ref = lookup_user_key(keyid,
605 if (!IS_ERR(key_ref))
610 ret = PTR_ERR(key_ref);
615 key = key_ref_to_ptr(key_ref);
616 desclen = strlen(key->description);
618 /* calculate how much information we're going to return */
620 infobuf = kasprintf(GFP_KERNEL,
623 from_kuid_munged(current_user_ns(), key->uid),
624 from_kgid_munged(current_user_ns(), key->gid),
628 infolen = strlen(infobuf);
629 ret = infolen + desclen + 1;
631 /* consider returning the data */
632 if (buffer && buflen >= ret) {
633 if (copy_to_user(buffer, infobuf, infolen) != 0 ||
634 copy_to_user(buffer + infolen, key->description,
641 key_ref_put(key_ref);
647 * Search the specified keyring and any keyrings it links to for a matching
648 * key. Only keyrings that grant the caller Search permission will be searched
649 * (this includes the starting keyring). Only keys with Search permission can
652 * If successful, the found key will be linked to the destination keyring if
653 * supplied and the key has Link permission, and the found key ID will be
656 long keyctl_keyring_search(key_serial_t ringid,
657 const char __user *_type,
658 const char __user *_description,
659 key_serial_t destringid)
661 struct key_type *ktype;
662 key_ref_t keyring_ref, key_ref, dest_ref;
663 char type[32], *description;
666 /* pull the type and description into kernel space */
667 ret = key_get_type_from_user(type, _type, sizeof(type));
671 description = strndup_user(_description, KEY_MAX_DESC_SIZE);
672 if (IS_ERR(description)) {
673 ret = PTR_ERR(description);
677 /* get the keyring at which to begin the search */
678 keyring_ref = lookup_user_key(ringid, 0, KEY_NEED_SEARCH);
679 if (IS_ERR(keyring_ref)) {
680 ret = PTR_ERR(keyring_ref);
684 /* get the destination keyring if specified */
687 dest_ref = lookup_user_key(destringid, KEY_LOOKUP_CREATE,
689 if (IS_ERR(dest_ref)) {
690 ret = PTR_ERR(dest_ref);
695 /* find the key type */
696 ktype = key_type_lookup(type);
698 ret = PTR_ERR(ktype);
703 key_ref = keyring_search(keyring_ref, ktype, description);
704 if (IS_ERR(key_ref)) {
705 ret = PTR_ERR(key_ref);
707 /* treat lack or presence of a negative key the same */
713 /* link the resulting key to the destination keyring if we can */
715 ret = key_permission(key_ref, KEY_NEED_LINK);
719 ret = key_link(key_ref_to_ptr(dest_ref), key_ref_to_ptr(key_ref));
724 ret = key_ref_to_ptr(key_ref)->serial;
727 key_ref_put(key_ref);
731 key_ref_put(dest_ref);
733 key_ref_put(keyring_ref);
741 * Read a key's payload.
743 * The key must either grant the caller Read permission, or it must grant the
744 * caller Search permission when searched for from the process keyrings.
746 * If successful, we place up to buflen bytes of data into the buffer, if one
747 * is provided, and return the amount of data that is available in the key,
748 * irrespective of how much we copied into the buffer.
750 long keyctl_read_key(key_serial_t keyid, char __user *buffer, size_t buflen)
756 /* find the key first */
757 key_ref = lookup_user_key(keyid, 0, 0);
758 if (IS_ERR(key_ref)) {
763 key = key_ref_to_ptr(key_ref);
765 ret = key_read_state(key);
767 goto error2; /* Negatively instantiated */
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 (key->state != KEY_IS_UNINSTANTIATED) {
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);
1410 ret = authkey->serial;
1417 * Get a key's the LSM security label.
1419 * The key must grant the caller View permission for this to work.
1421 * If there's a buffer, then up to buflen bytes of data will be placed into it.
1423 * If successful, the amount of information available will be returned,
1424 * irrespective of how much was copied (including the terminal NUL).
1426 long keyctl_get_security(key_serial_t keyid,
1427 char __user *buffer,
1430 struct key *key, *instkey;
1435 key_ref = lookup_user_key(keyid, KEY_LOOKUP_PARTIAL, KEY_NEED_VIEW);
1436 if (IS_ERR(key_ref)) {
1437 if (PTR_ERR(key_ref) != -EACCES)
1438 return PTR_ERR(key_ref);
1440 /* viewing a key under construction is also permitted if we
1441 * have the authorisation token handy */
1442 instkey = key_get_instantiation_authkey(keyid);
1443 if (IS_ERR(instkey))
1444 return PTR_ERR(instkey);
1447 key_ref = lookup_user_key(keyid, KEY_LOOKUP_PARTIAL, 0);
1448 if (IS_ERR(key_ref))
1449 return PTR_ERR(key_ref);
1452 key = key_ref_to_ptr(key_ref);
1453 ret = security_key_getsecurity(key, &context);
1455 /* if no information was returned, give userspace an empty
1458 if (buffer && buflen > 0 &&
1459 copy_to_user(buffer, "", 1) != 0)
1461 } else if (ret > 0) {
1462 /* return as much data as there's room for */
1463 if (buffer && buflen > 0) {
1467 if (copy_to_user(buffer, context, buflen) != 0)
1474 key_ref_put(key_ref);
1479 * Attempt to install the calling process's session keyring on the process's
1482 * The keyring must exist and must grant the caller LINK permission, and the
1483 * parent process must be single-threaded and must have the same effective
1484 * ownership as this process and mustn't be SUID/SGID.
1486 * The keyring will be emplaced on the parent when it next resumes userspace.
1488 * If successful, 0 will be returned.
1490 long keyctl_session_to_parent(void)
1492 struct task_struct *me, *parent;
1493 const struct cred *mycred, *pcred;
1494 struct callback_head *newwork, *oldwork;
1495 key_ref_t keyring_r;
1499 keyring_r = lookup_user_key(KEY_SPEC_SESSION_KEYRING, 0, KEY_NEED_LINK);
1500 if (IS_ERR(keyring_r))
1501 return PTR_ERR(keyring_r);
1505 /* our parent is going to need a new cred struct, a new tgcred struct
1506 * and new security data, so we allocate them here to prevent ENOMEM in
1508 cred = cred_alloc_blank();
1511 newwork = &cred->rcu;
1513 cred->session_keyring = key_ref_to_ptr(keyring_r);
1515 init_task_work(newwork, key_change_session_keyring);
1519 write_lock_irq(&tasklist_lock);
1523 parent = me->real_parent;
1525 /* the parent mustn't be init and mustn't be a kernel thread */
1526 if (parent->pid <= 1 || !parent->mm)
1529 /* the parent must be single threaded */
1530 if (!thread_group_empty(parent))
1533 /* the parent and the child must have different session keyrings or
1534 * there's no point */
1535 mycred = current_cred();
1536 pcred = __task_cred(parent);
1537 if (mycred == pcred ||
1538 mycred->session_keyring == pcred->session_keyring) {
1543 /* the parent must have the same effective ownership and mustn't be
1545 if (!uid_eq(pcred->uid, mycred->euid) ||
1546 !uid_eq(pcred->euid, mycred->euid) ||
1547 !uid_eq(pcred->suid, mycred->euid) ||
1548 !gid_eq(pcred->gid, mycred->egid) ||
1549 !gid_eq(pcred->egid, mycred->egid) ||
1550 !gid_eq(pcred->sgid, mycred->egid))
1553 /* the keyrings must have the same UID */
1554 if ((pcred->session_keyring &&
1555 !uid_eq(pcred->session_keyring->uid, mycred->euid)) ||
1556 !uid_eq(mycred->session_keyring->uid, mycred->euid))
1559 /* cancel an already pending keyring replacement */
1560 oldwork = task_work_cancel(parent, key_change_session_keyring);
1562 /* the replacement session keyring is applied just prior to userspace
1564 ret = task_work_add(parent, newwork, true);
1568 write_unlock_irq(&tasklist_lock);
1571 put_cred(container_of(oldwork, struct cred, rcu));
1577 key_ref_put(keyring_r);
1582 * Apply a restriction to a given keyring.
1584 * The caller must have Setattr permission to change keyring restrictions.
1586 * The requested type name may be a NULL pointer to reject all attempts
1587 * to link to the keyring. In this case, _restriction must also be NULL.
1588 * Otherwise, both _type and _restriction must be non-NULL.
1590 * Returns 0 if successful.
1592 long keyctl_restrict_keyring(key_serial_t id, const char __user *_type,
1593 const char __user *_restriction)
1597 char *restriction = NULL;
1600 key_ref = lookup_user_key(id, 0, KEY_NEED_SETATTR);
1601 if (IS_ERR(key_ref))
1602 return PTR_ERR(key_ref);
1609 ret = key_get_type_from_user(type, _type, sizeof(type));
1613 restriction = strndup_user(_restriction, PAGE_SIZE);
1614 if (IS_ERR(restriction)) {
1615 ret = PTR_ERR(restriction);
1623 ret = keyring_restrict(key_ref, _type ? type : NULL, restriction);
1626 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);
1746 case KEYCTL_PKEY_QUERY:
1749 return keyctl_pkey_query((key_serial_t)arg2,
1750 (const char __user *)arg4,
1751 (struct keyctl_pkey_query __user *)arg5);
1753 case KEYCTL_PKEY_ENCRYPT:
1754 case KEYCTL_PKEY_DECRYPT:
1755 case KEYCTL_PKEY_SIGN:
1756 return keyctl_pkey_e_d_s(
1758 (const struct keyctl_pkey_params __user *)arg2,
1759 (const char __user *)arg3,
1760 (const void __user *)arg4,
1761 (void __user *)arg5);
1763 case KEYCTL_PKEY_VERIFY:
1764 return keyctl_pkey_verify(
1765 (const struct keyctl_pkey_params __user *)arg2,
1766 (const char __user *)arg3,
1767 (const void __user *)arg4,
1768 (const void __user *)arg5);