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 const unsigned char keyrings_capabilities[2] = {
30 [0] = (KEYCTL_CAPS0_CAPABILITIES |
31 (IS_ENABLED(CONFIG_PERSISTENT_KEYRINGS) ? KEYCTL_CAPS0_PERSISTENT_KEYRINGS : 0) |
32 (IS_ENABLED(CONFIG_KEY_DH_OPERATIONS) ? KEYCTL_CAPS0_DIFFIE_HELLMAN : 0) |
33 (IS_ENABLED(CONFIG_ASYMMETRIC_KEY_TYPE) ? KEYCTL_CAPS0_PUBLIC_KEY : 0) |
34 (IS_ENABLED(CONFIG_BIG_KEYS) ? KEYCTL_CAPS0_BIG_KEY : 0) |
35 KEYCTL_CAPS0_INVALIDATE |
36 KEYCTL_CAPS0_RESTRICT_KEYRING |
39 [1] = (KEYCTL_CAPS1_NS_KEYRING_NAME |
40 KEYCTL_CAPS1_NS_KEY_TAG),
43 static int key_get_type_from_user(char *type,
44 const char __user *_type,
49 ret = strncpy_from_user(type, _type, len);
52 if (ret == 0 || ret >= len)
61 * Extract the description of a new key from userspace and either add it as a
62 * new key to the specified keyring or update a matching key in that keyring.
64 * If the description is NULL or an empty string, the key type is asked to
65 * generate one from the payload.
67 * The keyring must be writable so that we can attach the key to it.
69 * If successful, the new key's serial number is returned, otherwise an error
72 SYSCALL_DEFINE5(add_key, const char __user *, _type,
73 const char __user *, _description,
74 const void __user *, _payload,
78 key_ref_t keyring_ref, key_ref;
79 char type[32], *description;
84 if (plen > 1024 * 1024 - 1)
87 /* draw all the data into kernel space */
88 ret = key_get_type_from_user(type, _type, sizeof(type));
94 description = strndup_user(_description, KEY_MAX_DESC_SIZE);
95 if (IS_ERR(description)) {
96 ret = PTR_ERR(description);
102 } else if ((description[0] == '.') &&
103 (strncmp(type, "keyring", 7) == 0)) {
109 /* pull the payload in if one was supplied */
114 payload = kvmalloc(plen, GFP_KERNEL);
119 if (copy_from_user(payload, _payload, plen) != 0)
123 /* find the target keyring (which must be writable) */
124 keyring_ref = lookup_user_key(ringid, KEY_LOOKUP_CREATE, KEY_NEED_WRITE);
125 if (IS_ERR(keyring_ref)) {
126 ret = PTR_ERR(keyring_ref);
130 /* create or update the requested key and add it to the target
132 key_ref = key_create_or_update(keyring_ref, type, description,
133 payload, plen, KEY_PERM_UNDEF,
135 if (!IS_ERR(key_ref)) {
136 ret = key_ref_to_ptr(key_ref)->serial;
137 key_ref_put(key_ref);
140 ret = PTR_ERR(key_ref);
143 key_ref_put(keyring_ref);
146 memzero_explicit(payload, plen);
156 * Search the process keyrings and keyring trees linked from those for a
157 * matching key. Keyrings must have appropriate Search permission to be
160 * If a key is found, it will be attached to the destination keyring if there's
161 * one specified and the serial number of the key will be returned.
163 * If no key is found, /sbin/request-key will be invoked if _callout_info is
164 * non-NULL in an attempt to create a key. The _callout_info string will be
165 * passed to /sbin/request-key to aid with completing the request. If the
166 * _callout_info string is "" then it will be changed to "-".
168 SYSCALL_DEFINE4(request_key, const char __user *, _type,
169 const char __user *, _description,
170 const char __user *, _callout_info,
171 key_serial_t, destringid)
173 struct key_type *ktype;
177 char type[32], *description, *callout_info;
180 /* pull the type into kernel space */
181 ret = key_get_type_from_user(type, _type, sizeof(type));
185 /* pull the description into kernel space */
186 description = strndup_user(_description, KEY_MAX_DESC_SIZE);
187 if (IS_ERR(description)) {
188 ret = PTR_ERR(description);
192 /* pull the callout info into kernel space */
196 callout_info = strndup_user(_callout_info, PAGE_SIZE);
197 if (IS_ERR(callout_info)) {
198 ret = PTR_ERR(callout_info);
201 callout_len = strlen(callout_info);
204 /* get the destination keyring if specified */
207 dest_ref = lookup_user_key(destringid, KEY_LOOKUP_CREATE,
209 if (IS_ERR(dest_ref)) {
210 ret = PTR_ERR(dest_ref);
215 /* find the key type */
216 ktype = key_type_lookup(type);
218 ret = PTR_ERR(ktype);
223 key = request_key_and_link(ktype, description, NULL, callout_info,
224 callout_len, NULL, key_ref_to_ptr(dest_ref),
231 /* wait for the key to finish being constructed */
232 ret = wait_for_key_construction(key, 1);
243 key_ref_put(dest_ref);
253 * Get the ID of the specified process keyring.
255 * The requested keyring must have search permission to be found.
257 * If successful, the ID of the requested keyring will be returned.
259 long keyctl_get_keyring_ID(key_serial_t id, int create)
262 unsigned long lflags;
265 lflags = create ? KEY_LOOKUP_CREATE : 0;
266 key_ref = lookup_user_key(id, lflags, KEY_NEED_SEARCH);
267 if (IS_ERR(key_ref)) {
268 ret = PTR_ERR(key_ref);
272 ret = key_ref_to_ptr(key_ref)->serial;
273 key_ref_put(key_ref);
279 * Join a (named) session keyring.
281 * Create and join an anonymous session keyring or join a named session
282 * keyring, creating it if necessary. A named session keyring must have Search
283 * permission for it to be joined. Session keyrings without this permit will
284 * be skipped over. It is not permitted for userspace to create or join
285 * keyrings whose name begin with a dot.
287 * If successful, the ID of the joined session keyring will be returned.
289 long keyctl_join_session_keyring(const char __user *_name)
294 /* fetch the name from userspace */
297 name = strndup_user(_name, KEY_MAX_DESC_SIZE);
308 /* join the session */
309 ret = join_session_keyring(name);
317 * Update a key's data payload from the given data.
319 * The key must grant the caller Write permission and the key type must support
320 * updating for this to work. A negative key can be positively instantiated
323 * If successful, 0 will be returned. If the key type does not support
324 * updating, then -EOPNOTSUPP will be returned.
326 long keyctl_update_key(key_serial_t id,
327 const void __user *_payload,
335 if (plen > PAGE_SIZE)
338 /* pull the payload in if one was supplied */
342 payload = kmalloc(plen, GFP_KERNEL);
347 if (copy_from_user(payload, _payload, plen) != 0)
351 /* find the target key (which must be writable) */
352 key_ref = lookup_user_key(id, 0, KEY_NEED_WRITE);
353 if (IS_ERR(key_ref)) {
354 ret = PTR_ERR(key_ref);
359 ret = key_update(key_ref, payload, plen);
361 key_ref_put(key_ref);
371 * The key must be grant the caller Write or Setattr permission for this to
372 * work. The key type should give up its quota claim when revoked. The key
373 * and any links to the key will be automatically garbage collected after a
374 * certain amount of time (/proc/sys/kernel/keys/gc_delay).
376 * Keys with KEY_FLAG_KEEP set should not be revoked.
378 * If successful, 0 is returned.
380 long keyctl_revoke_key(key_serial_t id)
386 key_ref = lookup_user_key(id, 0, KEY_NEED_WRITE);
387 if (IS_ERR(key_ref)) {
388 ret = PTR_ERR(key_ref);
391 key_ref = lookup_user_key(id, 0, KEY_NEED_SETATTR);
392 if (IS_ERR(key_ref)) {
393 ret = PTR_ERR(key_ref);
398 key = key_ref_to_ptr(key_ref);
400 if (test_bit(KEY_FLAG_KEEP, &key->flags))
405 key_ref_put(key_ref);
413 * The key must be grant the caller Invalidate permission for this to work.
414 * The key and any links to the key will be automatically garbage collected
417 * Keys with KEY_FLAG_KEEP set should not be invalidated.
419 * If successful, 0 is returned.
421 long keyctl_invalidate_key(key_serial_t id)
429 key_ref = lookup_user_key(id, 0, KEY_NEED_SEARCH);
430 if (IS_ERR(key_ref)) {
431 ret = PTR_ERR(key_ref);
433 /* Root is permitted to invalidate certain special keys */
434 if (capable(CAP_SYS_ADMIN)) {
435 key_ref = lookup_user_key(id, 0, 0);
438 if (test_bit(KEY_FLAG_ROOT_CAN_INVAL,
439 &key_ref_to_ptr(key_ref)->flags))
448 key = key_ref_to_ptr(key_ref);
450 if (test_bit(KEY_FLAG_KEEP, &key->flags))
455 key_ref_put(key_ref);
457 kleave(" = %ld", ret);
462 * Clear the specified keyring, creating an empty process keyring if one of the
463 * special keyring IDs is used.
465 * The keyring must grant the caller Write permission and not have
466 * KEY_FLAG_KEEP set for this to work. If successful, 0 will be returned.
468 long keyctl_keyring_clear(key_serial_t ringid)
470 key_ref_t keyring_ref;
474 keyring_ref = lookup_user_key(ringid, KEY_LOOKUP_CREATE, KEY_NEED_WRITE);
475 if (IS_ERR(keyring_ref)) {
476 ret = PTR_ERR(keyring_ref);
478 /* Root is permitted to invalidate certain special keyrings */
479 if (capable(CAP_SYS_ADMIN)) {
480 keyring_ref = lookup_user_key(ringid, 0, 0);
481 if (IS_ERR(keyring_ref))
483 if (test_bit(KEY_FLAG_ROOT_CAN_CLEAR,
484 &key_ref_to_ptr(keyring_ref)->flags))
493 keyring = key_ref_to_ptr(keyring_ref);
494 if (test_bit(KEY_FLAG_KEEP, &keyring->flags))
497 ret = keyring_clear(keyring);
499 key_ref_put(keyring_ref);
505 * Create a link from a keyring to a key if there's no matching key in the
506 * keyring, otherwise replace the link to the matching key with a link to the
509 * The key must grant the caller Link permission and the the keyring must grant
510 * the caller Write permission. Furthermore, if an additional link is created,
511 * the keyring's quota will be extended.
513 * If successful, 0 will be returned.
515 long keyctl_keyring_link(key_serial_t id, key_serial_t ringid)
517 key_ref_t keyring_ref, key_ref;
520 keyring_ref = lookup_user_key(ringid, KEY_LOOKUP_CREATE, KEY_NEED_WRITE);
521 if (IS_ERR(keyring_ref)) {
522 ret = PTR_ERR(keyring_ref);
526 key_ref = lookup_user_key(id, KEY_LOOKUP_CREATE, KEY_NEED_LINK);
527 if (IS_ERR(key_ref)) {
528 ret = PTR_ERR(key_ref);
532 ret = key_link(key_ref_to_ptr(keyring_ref), key_ref_to_ptr(key_ref));
534 key_ref_put(key_ref);
536 key_ref_put(keyring_ref);
542 * Unlink a key from a keyring.
544 * The keyring must grant the caller Write permission for this to work; the key
545 * itself need not grant the caller anything. If the last link to a key is
546 * removed then that key will be scheduled for destruction.
548 * Keys or keyrings with KEY_FLAG_KEEP set should not be unlinked.
550 * If successful, 0 will be returned.
552 long keyctl_keyring_unlink(key_serial_t id, key_serial_t ringid)
554 key_ref_t keyring_ref, key_ref;
555 struct key *keyring, *key;
558 keyring_ref = lookup_user_key(ringid, 0, KEY_NEED_WRITE);
559 if (IS_ERR(keyring_ref)) {
560 ret = PTR_ERR(keyring_ref);
564 key_ref = lookup_user_key(id, KEY_LOOKUP_FOR_UNLINK, 0);
565 if (IS_ERR(key_ref)) {
566 ret = PTR_ERR(key_ref);
570 keyring = key_ref_to_ptr(keyring_ref);
571 key = key_ref_to_ptr(key_ref);
572 if (test_bit(KEY_FLAG_KEEP, &keyring->flags) &&
573 test_bit(KEY_FLAG_KEEP, &key->flags))
576 ret = key_unlink(keyring, key);
578 key_ref_put(key_ref);
580 key_ref_put(keyring_ref);
586 * Move a link to a key from one keyring to another, displacing any matching
587 * key from the destination keyring.
589 * The key must grant the caller Link permission and both keyrings must grant
590 * the caller Write permission. There must also be a link in the from keyring
591 * to the key. If both keyrings are the same, nothing is done.
593 * If successful, 0 will be returned.
595 long keyctl_keyring_move(key_serial_t id, key_serial_t from_ringid,
596 key_serial_t to_ringid, unsigned int flags)
598 key_ref_t key_ref, from_ref, to_ref;
601 if (flags & ~KEYCTL_MOVE_EXCL)
604 key_ref = lookup_user_key(id, KEY_LOOKUP_CREATE, KEY_NEED_LINK);
606 return PTR_ERR(key_ref);
608 from_ref = lookup_user_key(from_ringid, 0, KEY_NEED_WRITE);
609 if (IS_ERR(from_ref)) {
610 ret = PTR_ERR(from_ref);
614 to_ref = lookup_user_key(to_ringid, KEY_LOOKUP_CREATE, KEY_NEED_WRITE);
615 if (IS_ERR(to_ref)) {
616 ret = PTR_ERR(to_ref);
620 ret = key_move(key_ref_to_ptr(key_ref), key_ref_to_ptr(from_ref),
621 key_ref_to_ptr(to_ref), flags);
625 key_ref_put(from_ref);
627 key_ref_put(key_ref);
632 * Return a description of a key to userspace.
634 * The key must grant the caller View permission for this to work.
636 * If there's a buffer, we place up to buflen bytes of data into it formatted
637 * in the following way:
639 * type;uid;gid;perm;description<NUL>
641 * If successful, we return the amount of description available, irrespective
642 * of how much we may have copied into the buffer.
644 long keyctl_describe_key(key_serial_t keyid,
648 struct key *key, *instkey;
652 int desclen, infolen;
654 key_ref = lookup_user_key(keyid, KEY_LOOKUP_PARTIAL, KEY_NEED_VIEW);
655 if (IS_ERR(key_ref)) {
656 /* viewing a key under construction is permitted if we have the
657 * authorisation token handy */
658 if (PTR_ERR(key_ref) == -EACCES) {
659 instkey = key_get_instantiation_authkey(keyid);
660 if (!IS_ERR(instkey)) {
662 key_ref = lookup_user_key(keyid,
665 if (!IS_ERR(key_ref))
670 ret = PTR_ERR(key_ref);
675 key = key_ref_to_ptr(key_ref);
676 desclen = strlen(key->description);
678 /* calculate how much information we're going to return */
680 infobuf = kasprintf(GFP_KERNEL,
683 from_kuid_munged(current_user_ns(), key->uid),
684 from_kgid_munged(current_user_ns(), key->gid),
688 infolen = strlen(infobuf);
689 ret = infolen + desclen + 1;
691 /* consider returning the data */
692 if (buffer && buflen >= ret) {
693 if (copy_to_user(buffer, infobuf, infolen) != 0 ||
694 copy_to_user(buffer + infolen, key->description,
701 key_ref_put(key_ref);
707 * Search the specified keyring and any keyrings it links to for a matching
708 * key. Only keyrings that grant the caller Search permission will be searched
709 * (this includes the starting keyring). Only keys with Search permission can
712 * If successful, the found key will be linked to the destination keyring if
713 * supplied and the key has Link permission, and the found key ID will be
716 long keyctl_keyring_search(key_serial_t ringid,
717 const char __user *_type,
718 const char __user *_description,
719 key_serial_t destringid)
721 struct key_type *ktype;
722 key_ref_t keyring_ref, key_ref, dest_ref;
723 char type[32], *description;
726 /* pull the type and description into kernel space */
727 ret = key_get_type_from_user(type, _type, sizeof(type));
731 description = strndup_user(_description, KEY_MAX_DESC_SIZE);
732 if (IS_ERR(description)) {
733 ret = PTR_ERR(description);
737 /* get the keyring at which to begin the search */
738 keyring_ref = lookup_user_key(ringid, 0, KEY_NEED_SEARCH);
739 if (IS_ERR(keyring_ref)) {
740 ret = PTR_ERR(keyring_ref);
744 /* get the destination keyring if specified */
747 dest_ref = lookup_user_key(destringid, KEY_LOOKUP_CREATE,
749 if (IS_ERR(dest_ref)) {
750 ret = PTR_ERR(dest_ref);
755 /* find the key type */
756 ktype = key_type_lookup(type);
758 ret = PTR_ERR(ktype);
763 key_ref = keyring_search(keyring_ref, ktype, description, true);
764 if (IS_ERR(key_ref)) {
765 ret = PTR_ERR(key_ref);
767 /* treat lack or presence of a negative key the same */
773 /* link the resulting key to the destination keyring if we can */
775 ret = key_permission(key_ref, KEY_NEED_LINK);
779 ret = key_link(key_ref_to_ptr(dest_ref), key_ref_to_ptr(key_ref));
784 ret = key_ref_to_ptr(key_ref)->serial;
787 key_ref_put(key_ref);
791 key_ref_put(dest_ref);
793 key_ref_put(keyring_ref);
801 * Read a key's payload.
803 * The key must either grant the caller Read permission, or it must grant the
804 * caller Search permission when searched for from the process keyrings.
806 * If successful, we place up to buflen bytes of data into the buffer, if one
807 * is provided, and return the amount of data that is available in the key,
808 * irrespective of how much we copied into the buffer.
810 long keyctl_read_key(key_serial_t keyid, char __user *buffer, size_t buflen)
816 /* find the key first */
817 key_ref = lookup_user_key(keyid, 0, 0);
818 if (IS_ERR(key_ref)) {
823 key = key_ref_to_ptr(key_ref);
825 ret = key_read_state(key);
827 goto error2; /* Negatively instantiated */
829 /* see if we can read it directly */
830 ret = key_permission(key_ref, KEY_NEED_READ);
836 /* we can't; see if it's searchable from this process's keyrings
837 * - we automatically take account of the fact that it may be
838 * dangling off an instantiation key
840 if (!is_key_possessed(key_ref)) {
845 /* the key is probably readable - now try to read it */
848 if (key->type->read) {
849 /* Read the data with the semaphore held (since we might sleep)
850 * to protect against the key being updated or revoked.
852 down_read(&key->sem);
853 ret = key_validate(key);
855 ret = key->type->read(key, buffer, buflen);
866 * Change the ownership of a key
868 * The key must grant the caller Setattr permission for this to work, though
869 * the key need not be fully instantiated yet. For the UID to be changed, or
870 * for the GID to be changed to a group the caller is not a member of, the
871 * caller must have sysadmin capability. If either uid or gid is -1 then that
872 * attribute is not changed.
874 * If the UID is to be changed, the new user must have sufficient quota to
875 * accept the key. The quota deduction will be removed from the old user to
876 * the new user should the attribute be changed.
878 * If successful, 0 will be returned.
880 long keyctl_chown_key(key_serial_t id, uid_t user, gid_t group)
882 struct key_user *newowner, *zapowner = NULL;
889 uid = make_kuid(current_user_ns(), user);
890 gid = make_kgid(current_user_ns(), group);
892 if ((user != (uid_t) -1) && !uid_valid(uid))
894 if ((group != (gid_t) -1) && !gid_valid(gid))
898 if (user == (uid_t) -1 && group == (gid_t) -1)
901 key_ref = lookup_user_key(id, KEY_LOOKUP_CREATE | KEY_LOOKUP_PARTIAL,
903 if (IS_ERR(key_ref)) {
904 ret = PTR_ERR(key_ref);
908 key = key_ref_to_ptr(key_ref);
910 /* make the changes with the locks held to prevent chown/chown races */
912 down_write(&key->sem);
914 if (!capable(CAP_SYS_ADMIN)) {
915 /* only the sysadmin can chown a key to some other UID */
916 if (user != (uid_t) -1 && !uid_eq(key->uid, uid))
919 /* only the sysadmin can set the key's GID to a group other
920 * than one of those that the current process subscribes to */
921 if (group != (gid_t) -1 && !gid_eq(gid, key->gid) && !in_group_p(gid))
926 if (user != (uid_t) -1 && !uid_eq(uid, key->uid)) {
928 newowner = key_user_lookup(uid);
932 /* transfer the quota burden to the new user */
933 if (test_bit(KEY_FLAG_IN_QUOTA, &key->flags)) {
934 unsigned maxkeys = uid_eq(uid, GLOBAL_ROOT_UID) ?
935 key_quota_root_maxkeys : key_quota_maxkeys;
936 unsigned maxbytes = uid_eq(uid, GLOBAL_ROOT_UID) ?
937 key_quota_root_maxbytes : key_quota_maxbytes;
939 spin_lock(&newowner->lock);
940 if (newowner->qnkeys + 1 > maxkeys ||
941 newowner->qnbytes + key->quotalen > maxbytes ||
942 newowner->qnbytes + key->quotalen <
947 newowner->qnbytes += key->quotalen;
948 spin_unlock(&newowner->lock);
950 spin_lock(&key->user->lock);
952 key->user->qnbytes -= key->quotalen;
953 spin_unlock(&key->user->lock);
956 atomic_dec(&key->user->nkeys);
957 atomic_inc(&newowner->nkeys);
959 if (key->state != KEY_IS_UNINSTANTIATED) {
960 atomic_dec(&key->user->nikeys);
961 atomic_inc(&newowner->nikeys);
964 zapowner = key->user;
965 key->user = newowner;
970 if (group != (gid_t) -1)
979 key_user_put(zapowner);
984 spin_unlock(&newowner->lock);
991 * Change the permission mask on a key.
993 * The key must grant the caller Setattr permission for this to work, though
994 * the key need not be fully instantiated yet. If the caller does not have
995 * sysadmin capability, it may only change the permission on keys that it owns.
997 long keyctl_setperm_key(key_serial_t id, key_perm_t perm)
1004 if (perm & ~(KEY_POS_ALL | KEY_USR_ALL | KEY_GRP_ALL | KEY_OTH_ALL))
1007 key_ref = lookup_user_key(id, KEY_LOOKUP_CREATE | KEY_LOOKUP_PARTIAL,
1009 if (IS_ERR(key_ref)) {
1010 ret = PTR_ERR(key_ref);
1014 key = key_ref_to_ptr(key_ref);
1016 /* make the changes with the locks held to prevent chown/chmod races */
1018 down_write(&key->sem);
1020 /* if we're not the sysadmin, we can only change a key that we own */
1021 if (capable(CAP_SYS_ADMIN) || uid_eq(key->uid, current_fsuid())) {
1026 up_write(&key->sem);
1033 * Get the destination keyring for instantiation and check that the caller has
1034 * Write permission on it.
1036 static long get_instantiation_keyring(key_serial_t ringid,
1037 struct request_key_auth *rka,
1038 struct key **_dest_keyring)
1042 *_dest_keyring = NULL;
1044 /* just return a NULL pointer if we weren't asked to make a link */
1048 /* if a specific keyring is nominated by ID, then use that */
1050 dkref = lookup_user_key(ringid, KEY_LOOKUP_CREATE, KEY_NEED_WRITE);
1052 return PTR_ERR(dkref);
1053 *_dest_keyring = key_ref_to_ptr(dkref);
1057 if (ringid == KEY_SPEC_REQKEY_AUTH_KEY)
1060 /* otherwise specify the destination keyring recorded in the
1061 * authorisation key (any KEY_SPEC_*_KEYRING) */
1062 if (ringid >= KEY_SPEC_REQUESTOR_KEYRING) {
1063 *_dest_keyring = key_get(rka->dest_keyring);
1071 * Change the request_key authorisation key on the current process.
1073 static int keyctl_change_reqkey_auth(struct key *key)
1077 new = prepare_creds();
1081 key_put(new->request_key_auth);
1082 new->request_key_auth = key_get(key);
1084 return commit_creds(new);
1088 * Instantiate a key with the specified payload and link the key into the
1089 * destination keyring if one is given.
1091 * The caller must have the appropriate instantiation permit set for this to
1092 * work (see keyctl_assume_authority). No other permissions are required.
1094 * If successful, 0 will be returned.
1096 long keyctl_instantiate_key_common(key_serial_t id,
1097 struct iov_iter *from,
1098 key_serial_t ringid)
1100 const struct cred *cred = current_cred();
1101 struct request_key_auth *rka;
1102 struct key *instkey, *dest_keyring;
1103 size_t plen = from ? iov_iter_count(from) : 0;
1107 kenter("%d,,%zu,%d", id, plen, ringid);
1113 if (plen > 1024 * 1024 - 1)
1116 /* the appropriate instantiation authorisation key must have been
1117 * assumed before calling this */
1119 instkey = cred->request_key_auth;
1123 rka = instkey->payload.data[0];
1124 if (rka->target_key->serial != id)
1127 /* pull the payload in if one was supplied */
1132 payload = kvmalloc(plen, GFP_KERNEL);
1137 if (!copy_from_iter_full(payload, plen, from))
1141 /* find the destination keyring amongst those belonging to the
1142 * requesting task */
1143 ret = get_instantiation_keyring(ringid, rka, &dest_keyring);
1147 /* instantiate the key and link it into a keyring */
1148 ret = key_instantiate_and_link(rka->target_key, payload, plen,
1149 dest_keyring, instkey);
1151 key_put(dest_keyring);
1153 /* discard the assumed authority if it's just been disabled by
1154 * instantiation of the key */
1156 keyctl_change_reqkey_auth(NULL);
1160 memzero_explicit(payload, plen);
1168 * Instantiate a key with the specified payload and link the key into the
1169 * 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 * If successful, 0 will be returned.
1176 long keyctl_instantiate_key(key_serial_t id,
1177 const void __user *_payload,
1179 key_serial_t ringid)
1181 if (_payload && plen) {
1183 struct iov_iter from;
1186 ret = import_single_range(WRITE, (void __user *)_payload, plen,
1191 return keyctl_instantiate_key_common(id, &from, ringid);
1194 return keyctl_instantiate_key_common(id, NULL, ringid);
1198 * Instantiate a key with the specified multipart payload and link the key into
1199 * the destination keyring if one is given.
1201 * The caller must have the appropriate instantiation permit set for this to
1202 * work (see keyctl_assume_authority). No other permissions are required.
1204 * If successful, 0 will be returned.
1206 long keyctl_instantiate_key_iov(key_serial_t id,
1207 const struct iovec __user *_payload_iov,
1209 key_serial_t ringid)
1211 struct iovec iovstack[UIO_FASTIOV], *iov = iovstack;
1212 struct iov_iter from;
1218 ret = import_iovec(WRITE, _payload_iov, ioc,
1219 ARRAY_SIZE(iovstack), &iov, &from);
1222 ret = keyctl_instantiate_key_common(id, &from, ringid);
1228 * Negatively instantiate the key with the given timeout (in seconds) and link
1229 * the key into the destination keyring if one is given.
1231 * The caller must have the appropriate instantiation permit set for this to
1232 * work (see keyctl_assume_authority). No other permissions are required.
1234 * The key and any links to the key will be automatically garbage collected
1235 * after the timeout expires.
1237 * Negative keys are used to rate limit repeated request_key() calls by causing
1238 * them to return -ENOKEY until the negative key expires.
1240 * If successful, 0 will be returned.
1242 long keyctl_negate_key(key_serial_t id, unsigned timeout, key_serial_t ringid)
1244 return keyctl_reject_key(id, timeout, ENOKEY, ringid);
1248 * Negatively instantiate the key with the given timeout (in seconds) and error
1249 * code and link the key into the destination keyring if one is given.
1251 * The caller must have the appropriate instantiation permit set for this to
1252 * work (see keyctl_assume_authority). No other permissions are required.
1254 * The key and any links to the key will be automatically garbage collected
1255 * after the timeout expires.
1257 * Negative keys are used to rate limit repeated request_key() calls by causing
1258 * them to return the specified error code until the negative key expires.
1260 * If successful, 0 will be returned.
1262 long keyctl_reject_key(key_serial_t id, unsigned timeout, unsigned error,
1263 key_serial_t ringid)
1265 const struct cred *cred = current_cred();
1266 struct request_key_auth *rka;
1267 struct key *instkey, *dest_keyring;
1270 kenter("%d,%u,%u,%d", id, timeout, error, ringid);
1272 /* must be a valid error code and mustn't be a kernel special */
1274 error >= MAX_ERRNO ||
1275 error == ERESTARTSYS ||
1276 error == ERESTARTNOINTR ||
1277 error == ERESTARTNOHAND ||
1278 error == ERESTART_RESTARTBLOCK)
1281 /* the appropriate instantiation authorisation key must have been
1282 * assumed before calling this */
1284 instkey = cred->request_key_auth;
1288 rka = instkey->payload.data[0];
1289 if (rka->target_key->serial != id)
1292 /* find the destination keyring if present (which must also be
1294 ret = get_instantiation_keyring(ringid, rka, &dest_keyring);
1298 /* instantiate the key and link it into a keyring */
1299 ret = key_reject_and_link(rka->target_key, timeout, error,
1300 dest_keyring, instkey);
1302 key_put(dest_keyring);
1304 /* discard the assumed authority if it's just been disabled by
1305 * instantiation of the key */
1307 keyctl_change_reqkey_auth(NULL);
1314 * Read or set the default keyring in which request_key() will cache keys and
1315 * return the old setting.
1317 * If a thread or process keyring is specified then it will be created if it
1318 * doesn't yet exist. The old setting will be returned if successful.
1320 long keyctl_set_reqkey_keyring(int reqkey_defl)
1323 int ret, old_setting;
1325 old_setting = current_cred_xxx(jit_keyring);
1327 if (reqkey_defl == KEY_REQKEY_DEFL_NO_CHANGE)
1330 new = prepare_creds();
1334 switch (reqkey_defl) {
1335 case KEY_REQKEY_DEFL_THREAD_KEYRING:
1336 ret = install_thread_keyring_to_cred(new);
1341 case KEY_REQKEY_DEFL_PROCESS_KEYRING:
1342 ret = install_process_keyring_to_cred(new);
1347 case KEY_REQKEY_DEFL_DEFAULT:
1348 case KEY_REQKEY_DEFL_SESSION_KEYRING:
1349 case KEY_REQKEY_DEFL_USER_KEYRING:
1350 case KEY_REQKEY_DEFL_USER_SESSION_KEYRING:
1351 case KEY_REQKEY_DEFL_REQUESTOR_KEYRING:
1354 case KEY_REQKEY_DEFL_NO_CHANGE:
1355 case KEY_REQKEY_DEFL_GROUP_KEYRING:
1362 new->jit_keyring = reqkey_defl;
1371 * Set or clear the timeout on a key.
1373 * Either the key must grant the caller Setattr permission or else the caller
1374 * must hold an instantiation authorisation token for the key.
1376 * The timeout is either 0 to clear the timeout, or a number of seconds from
1377 * the current time. The key and any links to the key will be automatically
1378 * garbage collected after the timeout expires.
1380 * Keys with KEY_FLAG_KEEP set should not be timed out.
1382 * If successful, 0 is returned.
1384 long keyctl_set_timeout(key_serial_t id, unsigned timeout)
1386 struct key *key, *instkey;
1390 key_ref = lookup_user_key(id, KEY_LOOKUP_CREATE | KEY_LOOKUP_PARTIAL,
1392 if (IS_ERR(key_ref)) {
1393 /* setting the timeout on a key under construction is permitted
1394 * if we have the authorisation token handy */
1395 if (PTR_ERR(key_ref) == -EACCES) {
1396 instkey = key_get_instantiation_authkey(id);
1397 if (!IS_ERR(instkey)) {
1399 key_ref = lookup_user_key(id,
1402 if (!IS_ERR(key_ref))
1407 ret = PTR_ERR(key_ref);
1412 key = key_ref_to_ptr(key_ref);
1414 if (test_bit(KEY_FLAG_KEEP, &key->flags))
1417 key_set_timeout(key, timeout);
1425 * Assume (or clear) the authority to instantiate the specified key.
1427 * This sets the authoritative token currently in force for key instantiation.
1428 * This must be done for a key to be instantiated. It has the effect of making
1429 * available all the keys from the caller of the request_key() that created a
1430 * key to request_key() calls made by the caller of this function.
1432 * The caller must have the instantiation key in their process keyrings with a
1433 * Search permission grant available to the caller.
1435 * If the ID given is 0, then the setting will be cleared and 0 returned.
1437 * If the ID given has a matching an authorisation key, then that key will be
1438 * set and its ID will be returned. The authorisation key can be read to get
1439 * the callout information passed to request_key().
1441 long keyctl_assume_authority(key_serial_t id)
1443 struct key *authkey;
1446 /* special key IDs aren't permitted */
1451 /* we divest ourselves of authority if given an ID of 0 */
1453 ret = keyctl_change_reqkey_auth(NULL);
1457 /* attempt to assume the authority temporarily granted to us whilst we
1458 * instantiate the specified key
1459 * - the authorisation key must be in the current task's keyrings
1462 authkey = key_get_instantiation_authkey(id);
1463 if (IS_ERR(authkey)) {
1464 ret = PTR_ERR(authkey);
1468 ret = keyctl_change_reqkey_auth(authkey);
1470 ret = authkey->serial;
1477 * Get a key's the LSM security label.
1479 * The key must grant the caller View permission for this to work.
1481 * If there's a buffer, then up to buflen bytes of data will be placed into it.
1483 * If successful, the amount of information available will be returned,
1484 * irrespective of how much was copied (including the terminal NUL).
1486 long keyctl_get_security(key_serial_t keyid,
1487 char __user *buffer,
1490 struct key *key, *instkey;
1495 key_ref = lookup_user_key(keyid, KEY_LOOKUP_PARTIAL, KEY_NEED_VIEW);
1496 if (IS_ERR(key_ref)) {
1497 if (PTR_ERR(key_ref) != -EACCES)
1498 return PTR_ERR(key_ref);
1500 /* viewing a key under construction is also permitted if we
1501 * have the authorisation token handy */
1502 instkey = key_get_instantiation_authkey(keyid);
1503 if (IS_ERR(instkey))
1504 return PTR_ERR(instkey);
1507 key_ref = lookup_user_key(keyid, KEY_LOOKUP_PARTIAL, 0);
1508 if (IS_ERR(key_ref))
1509 return PTR_ERR(key_ref);
1512 key = key_ref_to_ptr(key_ref);
1513 ret = security_key_getsecurity(key, &context);
1515 /* if no information was returned, give userspace an empty
1518 if (buffer && buflen > 0 &&
1519 copy_to_user(buffer, "", 1) != 0)
1521 } else if (ret > 0) {
1522 /* return as much data as there's room for */
1523 if (buffer && buflen > 0) {
1527 if (copy_to_user(buffer, context, buflen) != 0)
1534 key_ref_put(key_ref);
1539 * Attempt to install the calling process's session keyring on the process's
1542 * The keyring must exist and must grant the caller LINK permission, and the
1543 * parent process must be single-threaded and must have the same effective
1544 * ownership as this process and mustn't be SUID/SGID.
1546 * The keyring will be emplaced on the parent when it next resumes userspace.
1548 * If successful, 0 will be returned.
1550 long keyctl_session_to_parent(void)
1552 struct task_struct *me, *parent;
1553 const struct cred *mycred, *pcred;
1554 struct callback_head *newwork, *oldwork;
1555 key_ref_t keyring_r;
1559 keyring_r = lookup_user_key(KEY_SPEC_SESSION_KEYRING, 0, KEY_NEED_LINK);
1560 if (IS_ERR(keyring_r))
1561 return PTR_ERR(keyring_r);
1565 /* our parent is going to need a new cred struct, a new tgcred struct
1566 * and new security data, so we allocate them here to prevent ENOMEM in
1568 cred = cred_alloc_blank();
1571 newwork = &cred->rcu;
1573 cred->session_keyring = key_ref_to_ptr(keyring_r);
1575 init_task_work(newwork, key_change_session_keyring);
1579 write_lock_irq(&tasklist_lock);
1583 parent = rcu_dereference_protected(me->real_parent,
1584 lockdep_is_held(&tasklist_lock));
1586 /* the parent mustn't be init and mustn't be a kernel thread */
1587 if (parent->pid <= 1 || !parent->mm)
1590 /* the parent must be single threaded */
1591 if (!thread_group_empty(parent))
1594 /* the parent and the child must have different session keyrings or
1595 * there's no point */
1596 mycred = current_cred();
1597 pcred = __task_cred(parent);
1598 if (mycred == pcred ||
1599 mycred->session_keyring == pcred->session_keyring) {
1604 /* the parent must have the same effective ownership and mustn't be
1606 if (!uid_eq(pcred->uid, mycred->euid) ||
1607 !uid_eq(pcred->euid, mycred->euid) ||
1608 !uid_eq(pcred->suid, mycred->euid) ||
1609 !gid_eq(pcred->gid, mycred->egid) ||
1610 !gid_eq(pcred->egid, mycred->egid) ||
1611 !gid_eq(pcred->sgid, mycred->egid))
1614 /* the keyrings must have the same UID */
1615 if ((pcred->session_keyring &&
1616 !uid_eq(pcred->session_keyring->uid, mycred->euid)) ||
1617 !uid_eq(mycred->session_keyring->uid, mycred->euid))
1620 /* cancel an already pending keyring replacement */
1621 oldwork = task_work_cancel(parent, key_change_session_keyring);
1623 /* the replacement session keyring is applied just prior to userspace
1625 ret = task_work_add(parent, newwork, true);
1629 write_unlock_irq(&tasklist_lock);
1632 put_cred(container_of(oldwork, struct cred, rcu));
1638 key_ref_put(keyring_r);
1643 * Apply a restriction to a given keyring.
1645 * The caller must have Setattr permission to change keyring restrictions.
1647 * The requested type name may be a NULL pointer to reject all attempts
1648 * to link to the keyring. In this case, _restriction must also be NULL.
1649 * Otherwise, both _type and _restriction must be non-NULL.
1651 * Returns 0 if successful.
1653 long keyctl_restrict_keyring(key_serial_t id, const char __user *_type,
1654 const char __user *_restriction)
1658 char *restriction = NULL;
1661 key_ref = lookup_user_key(id, 0, KEY_NEED_SETATTR);
1662 if (IS_ERR(key_ref))
1663 return PTR_ERR(key_ref);
1670 ret = key_get_type_from_user(type, _type, sizeof(type));
1674 restriction = strndup_user(_restriction, PAGE_SIZE);
1675 if (IS_ERR(restriction)) {
1676 ret = PTR_ERR(restriction);
1684 ret = keyring_restrict(key_ref, _type ? type : NULL, restriction);
1687 key_ref_put(key_ref);
1692 * Get keyrings subsystem capabilities.
1694 long keyctl_capabilities(unsigned char __user *_buffer, size_t buflen)
1696 size_t size = buflen;
1699 if (size > sizeof(keyrings_capabilities))
1700 size = sizeof(keyrings_capabilities);
1701 if (copy_to_user(_buffer, keyrings_capabilities, size) != 0)
1703 if (size < buflen &&
1704 clear_user(_buffer + size, buflen - size) != 0)
1708 return sizeof(keyrings_capabilities);
1712 * The key control system call
1714 SYSCALL_DEFINE5(keyctl, int, option, unsigned long, arg2, unsigned long, arg3,
1715 unsigned long, arg4, unsigned long, arg5)
1718 case KEYCTL_GET_KEYRING_ID:
1719 return keyctl_get_keyring_ID((key_serial_t) arg2,
1722 case KEYCTL_JOIN_SESSION_KEYRING:
1723 return keyctl_join_session_keyring((const char __user *) arg2);
1726 return keyctl_update_key((key_serial_t) arg2,
1727 (const void __user *) arg3,
1731 return keyctl_revoke_key((key_serial_t) arg2);
1733 case KEYCTL_DESCRIBE:
1734 return keyctl_describe_key((key_serial_t) arg2,
1735 (char __user *) arg3,
1739 return keyctl_keyring_clear((key_serial_t) arg2);
1742 return keyctl_keyring_link((key_serial_t) arg2,
1743 (key_serial_t) arg3);
1746 return keyctl_keyring_unlink((key_serial_t) arg2,
1747 (key_serial_t) arg3);
1750 return keyctl_keyring_search((key_serial_t) arg2,
1751 (const char __user *) arg3,
1752 (const char __user *) arg4,
1753 (key_serial_t) arg5);
1756 return keyctl_read_key((key_serial_t) arg2,
1757 (char __user *) arg3,
1761 return keyctl_chown_key((key_serial_t) arg2,
1765 case KEYCTL_SETPERM:
1766 return keyctl_setperm_key((key_serial_t) arg2,
1769 case KEYCTL_INSTANTIATE:
1770 return keyctl_instantiate_key((key_serial_t) arg2,
1771 (const void __user *) arg3,
1773 (key_serial_t) arg5);
1776 return keyctl_negate_key((key_serial_t) arg2,
1778 (key_serial_t) arg4);
1780 case KEYCTL_SET_REQKEY_KEYRING:
1781 return keyctl_set_reqkey_keyring(arg2);
1783 case KEYCTL_SET_TIMEOUT:
1784 return keyctl_set_timeout((key_serial_t) arg2,
1787 case KEYCTL_ASSUME_AUTHORITY:
1788 return keyctl_assume_authority((key_serial_t) arg2);
1790 case KEYCTL_GET_SECURITY:
1791 return keyctl_get_security((key_serial_t) arg2,
1792 (char __user *) arg3,
1795 case KEYCTL_SESSION_TO_PARENT:
1796 return keyctl_session_to_parent();
1799 return keyctl_reject_key((key_serial_t) arg2,
1802 (key_serial_t) arg5);
1804 case KEYCTL_INSTANTIATE_IOV:
1805 return keyctl_instantiate_key_iov(
1806 (key_serial_t) arg2,
1807 (const struct iovec __user *) arg3,
1809 (key_serial_t) arg5);
1811 case KEYCTL_INVALIDATE:
1812 return keyctl_invalidate_key((key_serial_t) arg2);
1814 case KEYCTL_GET_PERSISTENT:
1815 return keyctl_get_persistent((uid_t)arg2, (key_serial_t)arg3);
1817 case KEYCTL_DH_COMPUTE:
1818 return keyctl_dh_compute((struct keyctl_dh_params __user *) arg2,
1819 (char __user *) arg3, (size_t) arg4,
1820 (struct keyctl_kdf_params __user *) arg5);
1822 case KEYCTL_RESTRICT_KEYRING:
1823 return keyctl_restrict_keyring((key_serial_t) arg2,
1824 (const char __user *) arg3,
1825 (const char __user *) arg4);
1827 case KEYCTL_PKEY_QUERY:
1830 return keyctl_pkey_query((key_serial_t)arg2,
1831 (const char __user *)arg4,
1832 (struct keyctl_pkey_query __user *)arg5);
1834 case KEYCTL_PKEY_ENCRYPT:
1835 case KEYCTL_PKEY_DECRYPT:
1836 case KEYCTL_PKEY_SIGN:
1837 return keyctl_pkey_e_d_s(
1839 (const struct keyctl_pkey_params __user *)arg2,
1840 (const char __user *)arg3,
1841 (const void __user *)arg4,
1842 (void __user *)arg5);
1844 case KEYCTL_PKEY_VERIFY:
1845 return keyctl_pkey_verify(
1846 (const struct keyctl_pkey_params __user *)arg2,
1847 (const char __user *)arg3,
1848 (const void __user *)arg4,
1849 (const void __user *)arg5);
1852 return keyctl_keyring_move((key_serial_t)arg2,
1855 (unsigned int)arg5);
1857 case KEYCTL_CAPABILITIES:
1858 return keyctl_capabilities((unsigned char __user *)arg2, (size_t)arg3);