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 |
41 KEYCTL_CAPS1_ACL_ALTERABLE),
44 static int key_get_type_from_user(char *type,
45 const char __user *_type,
50 ret = strncpy_from_user(type, _type, len);
53 if (ret == 0 || ret >= len)
62 * Extract the description of a new key from userspace and either add it as a
63 * new key to the specified keyring or update a matching key in that keyring.
65 * If the description is NULL or an empty string, the key type is asked to
66 * generate one from the payload.
68 * The keyring must be writable so that we can attach the key to it.
70 * If successful, the new key's serial number is returned, otherwise an error
73 SYSCALL_DEFINE5(add_key, const char __user *, _type,
74 const char __user *, _description,
75 const void __user *, _payload,
79 key_ref_t keyring_ref, key_ref;
80 char type[32], *description;
85 if (plen > 1024 * 1024 - 1)
88 /* draw all the data into kernel space */
89 ret = key_get_type_from_user(type, _type, sizeof(type));
95 description = strndup_user(_description, KEY_MAX_DESC_SIZE);
96 if (IS_ERR(description)) {
97 ret = PTR_ERR(description);
103 } else if ((description[0] == '.') &&
104 (strncmp(type, "keyring", 7) == 0)) {
110 /* pull the payload in if one was supplied */
115 payload = kvmalloc(plen, GFP_KERNEL);
120 if (copy_from_user(payload, _payload, plen) != 0)
124 /* find the target keyring (which must be writable) */
125 keyring_ref = lookup_user_key(ringid, KEY_LOOKUP_CREATE, KEY_NEED_WRITE);
126 if (IS_ERR(keyring_ref)) {
127 ret = PTR_ERR(keyring_ref);
131 /* create or update the requested key and add it to the target
133 key_ref = key_create_or_update(keyring_ref, type, description,
134 payload, plen, NULL, KEY_ALLOC_IN_QUOTA);
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, NULL,
225 key_ref_to_ptr(dest_ref),
232 /* wait for the key to finish being constructed */
233 ret = wait_for_key_construction(key, 1);
244 key_ref_put(dest_ref);
254 * Get the ID of the specified process keyring.
256 * The requested keyring must have search permission to be found.
258 * If successful, the ID of the requested keyring will be returned.
260 long keyctl_get_keyring_ID(key_serial_t id, int create)
263 unsigned long lflags;
266 lflags = create ? KEY_LOOKUP_CREATE : 0;
267 key_ref = lookup_user_key(id, lflags, KEY_NEED_SEARCH);
268 if (IS_ERR(key_ref)) {
269 ret = PTR_ERR(key_ref);
273 ret = key_ref_to_ptr(key_ref)->serial;
274 key_ref_put(key_ref);
280 * Join a (named) session keyring.
282 * Create and join an anonymous session keyring or join a named session
283 * keyring, creating it if necessary. A named session keyring must have Search
284 * permission for it to be joined. Session keyrings without this permit will
285 * be skipped over. It is not permitted for userspace to create or join
286 * keyrings whose name begin with a dot.
288 * If successful, the ID of the joined session keyring will be returned.
290 long keyctl_join_session_keyring(const char __user *_name)
295 /* fetch the name from userspace */
298 name = strndup_user(_name, KEY_MAX_DESC_SIZE);
309 /* join the session */
310 ret = join_session_keyring(name);
318 * Update a key's data payload from the given data.
320 * The key must grant the caller Write permission and the key type must support
321 * updating for this to work. A negative key can be positively instantiated
324 * If successful, 0 will be returned. If the key type does not support
325 * updating, then -EOPNOTSUPP will be returned.
327 long keyctl_update_key(key_serial_t id,
328 const void __user *_payload,
336 if (plen > PAGE_SIZE)
339 /* pull the payload in if one was supplied */
343 payload = kmalloc(plen, GFP_KERNEL);
348 if (copy_from_user(payload, _payload, plen) != 0)
352 /* find the target key (which must be writable) */
353 key_ref = lookup_user_key(id, 0, KEY_NEED_WRITE);
354 if (IS_ERR(key_ref)) {
355 ret = PTR_ERR(key_ref);
360 ret = key_update(key_ref, payload, plen);
362 key_ref_put(key_ref);
372 * The key must be grant the caller Write or Setattr permission for this to
373 * work. The key type should give up its quota claim when revoked. The key
374 * and any links to the key will be automatically garbage collected after a
375 * certain amount of time (/proc/sys/kernel/keys/gc_delay).
377 * Keys with KEY_FLAG_KEEP set should not be revoked.
379 * If successful, 0 is returned.
381 long keyctl_revoke_key(key_serial_t id)
387 key_ref = lookup_user_key(id, 0, KEY_NEED_REVOKE);
388 if (IS_ERR(key_ref)) {
389 ret = PTR_ERR(key_ref);
393 key = key_ref_to_ptr(key_ref);
395 if (test_bit(KEY_FLAG_KEEP, &key->flags))
400 key_ref_put(key_ref);
408 * The key must be grant the caller Invalidate permission for this to work.
409 * The key and any links to the key will be automatically garbage collected
412 * Keys with KEY_FLAG_KEEP set should not be invalidated.
414 * If successful, 0 is returned.
416 long keyctl_invalidate_key(key_serial_t id)
424 key_ref = lookup_user_key(id, 0, KEY_NEED_INVAL);
425 if (IS_ERR(key_ref)) {
426 ret = PTR_ERR(key_ref);
428 /* Root is permitted to invalidate certain special keys */
429 if (capable(CAP_SYS_ADMIN)) {
430 key_ref = lookup_user_key(id, 0, 0);
433 if (test_bit(KEY_FLAG_ROOT_CAN_INVAL,
434 &key_ref_to_ptr(key_ref)->flags))
443 key = key_ref_to_ptr(key_ref);
445 if (test_bit(KEY_FLAG_KEEP, &key->flags))
450 key_ref_put(key_ref);
452 kleave(" = %ld", ret);
457 * Clear the specified keyring, creating an empty process keyring if one of the
458 * special keyring IDs is used.
460 * The keyring must grant the caller Write permission and not have
461 * KEY_FLAG_KEEP set for this to work. If successful, 0 will be returned.
463 long keyctl_keyring_clear(key_serial_t ringid)
465 key_ref_t keyring_ref;
469 keyring_ref = lookup_user_key(ringid, KEY_LOOKUP_CREATE, KEY_NEED_CLEAR);
470 if (IS_ERR(keyring_ref)) {
471 ret = PTR_ERR(keyring_ref);
473 /* Root is permitted to invalidate certain special keyrings */
474 if (capable(CAP_SYS_ADMIN)) {
475 keyring_ref = lookup_user_key(ringid, 0, 0);
476 if (IS_ERR(keyring_ref))
478 if (test_bit(KEY_FLAG_ROOT_CAN_CLEAR,
479 &key_ref_to_ptr(keyring_ref)->flags))
488 keyring = key_ref_to_ptr(keyring_ref);
489 if (test_bit(KEY_FLAG_KEEP, &keyring->flags))
492 ret = keyring_clear(keyring);
494 key_ref_put(keyring_ref);
500 * Create a link from a keyring to a key if there's no matching key in the
501 * keyring, otherwise replace the link to the matching key with a link to the
504 * The key must grant the caller Link permission and the the keyring must grant
505 * the caller Write permission. Furthermore, if an additional link is created,
506 * the keyring's quota will be extended.
508 * If successful, 0 will be returned.
510 long keyctl_keyring_link(key_serial_t id, key_serial_t ringid)
512 key_ref_t keyring_ref, key_ref;
515 keyring_ref = lookup_user_key(ringid, KEY_LOOKUP_CREATE, KEY_NEED_WRITE);
516 if (IS_ERR(keyring_ref)) {
517 ret = PTR_ERR(keyring_ref);
521 key_ref = lookup_user_key(id, KEY_LOOKUP_CREATE, KEY_NEED_LINK);
522 if (IS_ERR(key_ref)) {
523 ret = PTR_ERR(key_ref);
527 ret = key_link(key_ref_to_ptr(keyring_ref), key_ref_to_ptr(key_ref));
529 key_ref_put(key_ref);
531 key_ref_put(keyring_ref);
537 * Unlink a key from a keyring.
539 * The keyring must grant the caller Write permission for this to work; the key
540 * itself need not grant the caller anything. If the last link to a key is
541 * removed then that key will be scheduled for destruction.
543 * Keys or keyrings with KEY_FLAG_KEEP set should not be unlinked.
545 * If successful, 0 will be returned.
547 long keyctl_keyring_unlink(key_serial_t id, key_serial_t ringid)
549 key_ref_t keyring_ref, key_ref;
550 struct key *keyring, *key;
553 keyring_ref = lookup_user_key(ringid, 0, KEY_NEED_WRITE);
554 if (IS_ERR(keyring_ref)) {
555 ret = PTR_ERR(keyring_ref);
559 key_ref = lookup_user_key(id, KEY_LOOKUP_FOR_UNLINK, 0);
560 if (IS_ERR(key_ref)) {
561 ret = PTR_ERR(key_ref);
565 keyring = key_ref_to_ptr(keyring_ref);
566 key = key_ref_to_ptr(key_ref);
567 if (test_bit(KEY_FLAG_KEEP, &keyring->flags) &&
568 test_bit(KEY_FLAG_KEEP, &key->flags))
571 ret = key_unlink(keyring, key);
573 key_ref_put(key_ref);
575 key_ref_put(keyring_ref);
581 * Move a link to a key from one keyring to another, displacing any matching
582 * key from the destination keyring.
584 * The key must grant the caller Link permission and both keyrings must grant
585 * the caller Write permission. There must also be a link in the from keyring
586 * to the key. If both keyrings are the same, nothing is done.
588 * If successful, 0 will be returned.
590 long keyctl_keyring_move(key_serial_t id, key_serial_t from_ringid,
591 key_serial_t to_ringid, unsigned int flags)
593 key_ref_t key_ref, from_ref, to_ref;
596 if (flags & ~KEYCTL_MOVE_EXCL)
599 key_ref = lookup_user_key(id, KEY_LOOKUP_CREATE, KEY_NEED_LINK);
601 return PTR_ERR(key_ref);
603 from_ref = lookup_user_key(from_ringid, 0, KEY_NEED_WRITE);
604 if (IS_ERR(from_ref)) {
605 ret = PTR_ERR(from_ref);
609 to_ref = lookup_user_key(to_ringid, KEY_LOOKUP_CREATE, KEY_NEED_WRITE);
610 if (IS_ERR(to_ref)) {
611 ret = PTR_ERR(to_ref);
615 ret = key_move(key_ref_to_ptr(key_ref), key_ref_to_ptr(from_ref),
616 key_ref_to_ptr(to_ref), flags);
620 key_ref_put(from_ref);
622 key_ref_put(key_ref);
627 * Return a description of a key to userspace.
629 * The key must grant the caller View permission for this to work.
631 * If there's a buffer, we place up to buflen bytes of data into it formatted
632 * in the following way:
634 * type;uid;gid;perm;description<NUL>
636 * If successful, we return the amount of description available, irrespective
637 * of how much we may have copied into the buffer.
639 long keyctl_describe_key(key_serial_t keyid,
643 struct key *key, *instkey;
648 int desclen, infolen;
650 key_ref = lookup_user_key(keyid, KEY_LOOKUP_PARTIAL, KEY_NEED_VIEW);
651 if (IS_ERR(key_ref)) {
652 /* viewing a key under construction is permitted if we have the
653 * authorisation token handy */
654 if (PTR_ERR(key_ref) == -EACCES) {
655 instkey = key_get_instantiation_authkey(keyid);
656 if (!IS_ERR(instkey)) {
658 key_ref = lookup_user_key(keyid,
661 if (!IS_ERR(key_ref))
666 ret = PTR_ERR(key_ref);
671 key = key_ref_to_ptr(key_ref);
672 desclen = strlen(key->description);
675 perm = key_acl_to_perm(rcu_dereference(key->acl));
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, unsigned int perm)
1005 if (perm & ~(KEY_POS_ALL | KEY_USR_ALL | KEY_GRP_ALL | KEY_OTH_ALL))
1009 if (perm & KEY_POS_ALL) nr++;
1010 if (perm & KEY_USR_ALL) nr++;
1011 if (perm & KEY_GRP_ALL) nr++;
1012 if (perm & KEY_OTH_ALL) nr++;
1014 key_ref = lookup_user_key(id, KEY_LOOKUP_CREATE | KEY_LOOKUP_PARTIAL,
1016 if (IS_ERR(key_ref)) {
1017 ret = PTR_ERR(key_ref);
1021 key = key_ref_to_ptr(key_ref);
1024 if (test_bit(KEY_FLAG_HAS_ACL, &key->flags))
1028 acl = kzalloc(struct_size(acl, aces, nr), GFP_KERNEL);
1032 refcount_set(&acl->usage, 1);
1035 for (i = 0; i < 4; i++) {
1036 struct key_ace *ace = &acl->aces[j];
1037 unsigned int subset = (perm >> (i * 8)) & KEY_OTH_ALL;
1041 ace->type = KEY_ACE_SUBJ_STANDARD;
1042 ace->subject_id = KEY_ACE_EVERYONE + i;
1044 if (subset & (KEY_OTH_WRITE | KEY_OTH_SETATTR))
1045 ace->perm |= KEY_ACE_REVOKE;
1046 if (subset & KEY_OTH_SEARCH)
1047 ace->perm |= KEY_ACE_INVAL;
1048 if (key->type == &key_type_keyring) {
1049 if (subset & KEY_OTH_SEARCH)
1050 ace->perm |= KEY_ACE_JOIN;
1051 if (subset & KEY_OTH_WRITE)
1052 ace->perm |= KEY_ACE_CLEAR;
1057 /* make the changes with the locks held to prevent chown/chmod races */
1058 down_write(&key->sem);
1059 ret = key_set_acl(key, acl);
1060 up_write(&key->sem);
1068 * Get the destination keyring for instantiation and check that the caller has
1069 * Write permission on it.
1071 static long get_instantiation_keyring(key_serial_t ringid,
1072 struct request_key_auth *rka,
1073 struct key **_dest_keyring)
1077 *_dest_keyring = NULL;
1079 /* just return a NULL pointer if we weren't asked to make a link */
1083 /* if a specific keyring is nominated by ID, then use that */
1085 dkref = lookup_user_key(ringid, KEY_LOOKUP_CREATE, KEY_NEED_WRITE);
1087 return PTR_ERR(dkref);
1088 *_dest_keyring = key_ref_to_ptr(dkref);
1092 if (ringid == KEY_SPEC_REQKEY_AUTH_KEY)
1095 /* otherwise specify the destination keyring recorded in the
1096 * authorisation key (any KEY_SPEC_*_KEYRING) */
1097 if (ringid >= KEY_SPEC_REQUESTOR_KEYRING) {
1098 *_dest_keyring = key_get(rka->dest_keyring);
1106 * Change the request_key authorisation key on the current process.
1108 static int keyctl_change_reqkey_auth(struct key *key)
1112 new = prepare_creds();
1116 key_put(new->request_key_auth);
1117 new->request_key_auth = key_get(key);
1119 return commit_creds(new);
1123 * Instantiate a key with the specified payload and link the key into the
1124 * destination keyring if one is given.
1126 * The caller must have the appropriate instantiation permit set for this to
1127 * work (see keyctl_assume_authority). No other permissions are required.
1129 * If successful, 0 will be returned.
1131 long keyctl_instantiate_key_common(key_serial_t id,
1132 struct iov_iter *from,
1133 key_serial_t ringid)
1135 const struct cred *cred = current_cred();
1136 struct request_key_auth *rka;
1137 struct key *instkey, *dest_keyring;
1138 size_t plen = from ? iov_iter_count(from) : 0;
1142 kenter("%d,,%zu,%d", id, plen, ringid);
1148 if (plen > 1024 * 1024 - 1)
1151 /* the appropriate instantiation authorisation key must have been
1152 * assumed before calling this */
1154 instkey = cred->request_key_auth;
1158 rka = instkey->payload.data[0];
1159 if (rka->target_key->serial != id)
1162 /* pull the payload in if one was supplied */
1167 payload = kvmalloc(plen, GFP_KERNEL);
1172 if (!copy_from_iter_full(payload, plen, from))
1176 /* find the destination keyring amongst those belonging to the
1177 * requesting task */
1178 ret = get_instantiation_keyring(ringid, rka, &dest_keyring);
1182 /* instantiate the key and link it into a keyring */
1183 ret = key_instantiate_and_link(rka->target_key, payload, plen,
1184 dest_keyring, instkey);
1186 key_put(dest_keyring);
1188 /* discard the assumed authority if it's just been disabled by
1189 * instantiation of the key */
1191 keyctl_change_reqkey_auth(NULL);
1195 memzero_explicit(payload, plen);
1203 * Instantiate a key with the specified payload and link the key into the
1204 * destination keyring if one is given.
1206 * The caller must have the appropriate instantiation permit set for this to
1207 * work (see keyctl_assume_authority). No other permissions are required.
1209 * If successful, 0 will be returned.
1211 long keyctl_instantiate_key(key_serial_t id,
1212 const void __user *_payload,
1214 key_serial_t ringid)
1216 if (_payload && plen) {
1218 struct iov_iter from;
1221 ret = import_single_range(WRITE, (void __user *)_payload, plen,
1226 return keyctl_instantiate_key_common(id, &from, ringid);
1229 return keyctl_instantiate_key_common(id, NULL, ringid);
1233 * Instantiate a key with the specified multipart payload and link the key into
1234 * the destination keyring if one is given.
1236 * The caller must have the appropriate instantiation permit set for this to
1237 * work (see keyctl_assume_authority). No other permissions are required.
1239 * If successful, 0 will be returned.
1241 long keyctl_instantiate_key_iov(key_serial_t id,
1242 const struct iovec __user *_payload_iov,
1244 key_serial_t ringid)
1246 struct iovec iovstack[UIO_FASTIOV], *iov = iovstack;
1247 struct iov_iter from;
1253 ret = import_iovec(WRITE, _payload_iov, ioc,
1254 ARRAY_SIZE(iovstack), &iov, &from);
1257 ret = keyctl_instantiate_key_common(id, &from, ringid);
1263 * Negatively instantiate the key with the given timeout (in seconds) and link
1264 * the key into the destination keyring if one is given.
1266 * The caller must have the appropriate instantiation permit set for this to
1267 * work (see keyctl_assume_authority). No other permissions are required.
1269 * The key and any links to the key will be automatically garbage collected
1270 * after the timeout expires.
1272 * Negative keys are used to rate limit repeated request_key() calls by causing
1273 * them to return -ENOKEY until the negative key expires.
1275 * If successful, 0 will be returned.
1277 long keyctl_negate_key(key_serial_t id, unsigned timeout, key_serial_t ringid)
1279 return keyctl_reject_key(id, timeout, ENOKEY, ringid);
1283 * Negatively instantiate the key with the given timeout (in seconds) and error
1284 * code and link the key into the destination keyring if one is given.
1286 * The caller must have the appropriate instantiation permit set for this to
1287 * work (see keyctl_assume_authority). No other permissions are required.
1289 * The key and any links to the key will be automatically garbage collected
1290 * after the timeout expires.
1292 * Negative keys are used to rate limit repeated request_key() calls by causing
1293 * them to return the specified error code until the negative key expires.
1295 * If successful, 0 will be returned.
1297 long keyctl_reject_key(key_serial_t id, unsigned timeout, unsigned error,
1298 key_serial_t ringid)
1300 const struct cred *cred = current_cred();
1301 struct request_key_auth *rka;
1302 struct key *instkey, *dest_keyring;
1305 kenter("%d,%u,%u,%d", id, timeout, error, ringid);
1307 /* must be a valid error code and mustn't be a kernel special */
1309 error >= MAX_ERRNO ||
1310 error == ERESTARTSYS ||
1311 error == ERESTARTNOINTR ||
1312 error == ERESTARTNOHAND ||
1313 error == ERESTART_RESTARTBLOCK)
1316 /* the appropriate instantiation authorisation key must have been
1317 * assumed before calling this */
1319 instkey = cred->request_key_auth;
1323 rka = instkey->payload.data[0];
1324 if (rka->target_key->serial != id)
1327 /* find the destination keyring if present (which must also be
1329 ret = get_instantiation_keyring(ringid, rka, &dest_keyring);
1333 /* instantiate the key and link it into a keyring */
1334 ret = key_reject_and_link(rka->target_key, timeout, error,
1335 dest_keyring, instkey);
1337 key_put(dest_keyring);
1339 /* discard the assumed authority if it's just been disabled by
1340 * instantiation of the key */
1342 keyctl_change_reqkey_auth(NULL);
1349 * Read or set the default keyring in which request_key() will cache keys and
1350 * return the old setting.
1352 * If a thread or process keyring is specified then it will be created if it
1353 * doesn't yet exist. The old setting will be returned if successful.
1355 long keyctl_set_reqkey_keyring(int reqkey_defl)
1358 int ret, old_setting;
1360 old_setting = current_cred_xxx(jit_keyring);
1362 if (reqkey_defl == KEY_REQKEY_DEFL_NO_CHANGE)
1365 new = prepare_creds();
1369 switch (reqkey_defl) {
1370 case KEY_REQKEY_DEFL_THREAD_KEYRING:
1371 ret = install_thread_keyring_to_cred(new);
1376 case KEY_REQKEY_DEFL_PROCESS_KEYRING:
1377 ret = install_process_keyring_to_cred(new);
1382 case KEY_REQKEY_DEFL_DEFAULT:
1383 case KEY_REQKEY_DEFL_SESSION_KEYRING:
1384 case KEY_REQKEY_DEFL_USER_KEYRING:
1385 case KEY_REQKEY_DEFL_USER_SESSION_KEYRING:
1386 case KEY_REQKEY_DEFL_REQUESTOR_KEYRING:
1389 case KEY_REQKEY_DEFL_NO_CHANGE:
1390 case KEY_REQKEY_DEFL_GROUP_KEYRING:
1397 new->jit_keyring = reqkey_defl;
1406 * Set or clear the timeout on a key.
1408 * Either the key must grant the caller Setattr permission or else the caller
1409 * must hold an instantiation authorisation token for the key.
1411 * The timeout is either 0 to clear the timeout, or a number of seconds from
1412 * the current time. The key and any links to the key will be automatically
1413 * garbage collected after the timeout expires.
1415 * Keys with KEY_FLAG_KEEP set should not be timed out.
1417 * If successful, 0 is returned.
1419 long keyctl_set_timeout(key_serial_t id, unsigned timeout)
1421 struct key *key, *instkey;
1425 key_ref = lookup_user_key(id, KEY_LOOKUP_CREATE | KEY_LOOKUP_PARTIAL,
1427 if (IS_ERR(key_ref)) {
1428 /* setting the timeout on a key under construction is permitted
1429 * if we have the authorisation token handy */
1430 if (PTR_ERR(key_ref) == -EACCES) {
1431 instkey = key_get_instantiation_authkey(id);
1432 if (!IS_ERR(instkey)) {
1434 key_ref = lookup_user_key(id,
1437 if (!IS_ERR(key_ref))
1442 ret = PTR_ERR(key_ref);
1447 key = key_ref_to_ptr(key_ref);
1449 if (test_bit(KEY_FLAG_KEEP, &key->flags))
1452 key_set_timeout(key, timeout);
1460 * Assume (or clear) the authority to instantiate the specified key.
1462 * This sets the authoritative token currently in force for key instantiation.
1463 * This must be done for a key to be instantiated. It has the effect of making
1464 * available all the keys from the caller of the request_key() that created a
1465 * key to request_key() calls made by the caller of this function.
1467 * The caller must have the instantiation key in their process keyrings with a
1468 * Search permission grant available to the caller.
1470 * If the ID given is 0, then the setting will be cleared and 0 returned.
1472 * If the ID given has a matching an authorisation key, then that key will be
1473 * set and its ID will be returned. The authorisation key can be read to get
1474 * the callout information passed to request_key().
1476 long keyctl_assume_authority(key_serial_t id)
1478 struct key *authkey;
1481 /* special key IDs aren't permitted */
1486 /* we divest ourselves of authority if given an ID of 0 */
1488 ret = keyctl_change_reqkey_auth(NULL);
1492 /* attempt to assume the authority temporarily granted to us whilst we
1493 * instantiate the specified key
1494 * - the authorisation key must be in the current task's keyrings
1497 authkey = key_get_instantiation_authkey(id);
1498 if (IS_ERR(authkey)) {
1499 ret = PTR_ERR(authkey);
1503 ret = keyctl_change_reqkey_auth(authkey);
1505 ret = authkey->serial;
1512 * Get a key's the LSM security label.
1514 * The key must grant the caller View permission for this to work.
1516 * If there's a buffer, then up to buflen bytes of data will be placed into it.
1518 * If successful, the amount of information available will be returned,
1519 * irrespective of how much was copied (including the terminal NUL).
1521 long keyctl_get_security(key_serial_t keyid,
1522 char __user *buffer,
1525 struct key *key, *instkey;
1530 key_ref = lookup_user_key(keyid, KEY_LOOKUP_PARTIAL, KEY_NEED_VIEW);
1531 if (IS_ERR(key_ref)) {
1532 if (PTR_ERR(key_ref) != -EACCES)
1533 return PTR_ERR(key_ref);
1535 /* viewing a key under construction is also permitted if we
1536 * have the authorisation token handy */
1537 instkey = key_get_instantiation_authkey(keyid);
1538 if (IS_ERR(instkey))
1539 return PTR_ERR(instkey);
1542 key_ref = lookup_user_key(keyid, KEY_LOOKUP_PARTIAL, 0);
1543 if (IS_ERR(key_ref))
1544 return PTR_ERR(key_ref);
1547 key = key_ref_to_ptr(key_ref);
1548 ret = security_key_getsecurity(key, &context);
1550 /* if no information was returned, give userspace an empty
1553 if (buffer && buflen > 0 &&
1554 copy_to_user(buffer, "", 1) != 0)
1556 } else if (ret > 0) {
1557 /* return as much data as there's room for */
1558 if (buffer && buflen > 0) {
1562 if (copy_to_user(buffer, context, buflen) != 0)
1569 key_ref_put(key_ref);
1574 * Attempt to install the calling process's session keyring on the process's
1577 * The keyring must exist and must grant the caller JOIN permission, and the
1578 * parent process must be single-threaded and must have the same effective
1579 * ownership as this process and mustn't be SUID/SGID.
1581 * The keyring will be emplaced on the parent when it next resumes userspace.
1583 * If successful, 0 will be returned.
1585 long keyctl_session_to_parent(void)
1587 struct task_struct *me, *parent;
1588 const struct cred *mycred, *pcred;
1589 struct callback_head *newwork, *oldwork;
1590 key_ref_t keyring_r;
1594 keyring_r = lookup_user_key(KEY_SPEC_SESSION_KEYRING, 0, KEY_NEED_JOIN);
1595 if (IS_ERR(keyring_r))
1596 return PTR_ERR(keyring_r);
1600 /* our parent is going to need a new cred struct, a new tgcred struct
1601 * and new security data, so we allocate them here to prevent ENOMEM in
1603 cred = cred_alloc_blank();
1606 newwork = &cred->rcu;
1608 cred->session_keyring = key_ref_to_ptr(keyring_r);
1610 init_task_work(newwork, key_change_session_keyring);
1614 write_lock_irq(&tasklist_lock);
1618 parent = rcu_dereference_protected(me->real_parent,
1619 lockdep_is_held(&tasklist_lock));
1621 /* the parent mustn't be init and mustn't be a kernel thread */
1622 if (parent->pid <= 1 || !parent->mm)
1625 /* the parent must be single threaded */
1626 if (!thread_group_empty(parent))
1629 /* the parent and the child must have different session keyrings or
1630 * there's no point */
1631 mycred = current_cred();
1632 pcred = __task_cred(parent);
1633 if (mycred == pcred ||
1634 mycred->session_keyring == pcred->session_keyring) {
1639 /* the parent must have the same effective ownership and mustn't be
1641 if (!uid_eq(pcred->uid, mycred->euid) ||
1642 !uid_eq(pcred->euid, mycred->euid) ||
1643 !uid_eq(pcred->suid, mycred->euid) ||
1644 !gid_eq(pcred->gid, mycred->egid) ||
1645 !gid_eq(pcred->egid, mycred->egid) ||
1646 !gid_eq(pcred->sgid, mycred->egid))
1649 /* the keyrings must have the same UID */
1650 if ((pcred->session_keyring &&
1651 !uid_eq(pcred->session_keyring->uid, mycred->euid)) ||
1652 !uid_eq(mycred->session_keyring->uid, mycred->euid))
1655 /* cancel an already pending keyring replacement */
1656 oldwork = task_work_cancel(parent, key_change_session_keyring);
1658 /* the replacement session keyring is applied just prior to userspace
1660 ret = task_work_add(parent, newwork, true);
1664 write_unlock_irq(&tasklist_lock);
1667 put_cred(container_of(oldwork, struct cred, rcu));
1673 key_ref_put(keyring_r);
1678 * Apply a restriction to a given keyring.
1680 * The caller must have Setattr permission to change keyring restrictions.
1682 * The requested type name may be a NULL pointer to reject all attempts
1683 * to link to the keyring. In this case, _restriction must also be NULL.
1684 * Otherwise, both _type and _restriction must be non-NULL.
1686 * Returns 0 if successful.
1688 long keyctl_restrict_keyring(key_serial_t id, const char __user *_type,
1689 const char __user *_restriction)
1693 char *restriction = NULL;
1696 key_ref = lookup_user_key(id, 0, KEY_NEED_SETSEC);
1697 if (IS_ERR(key_ref))
1698 return PTR_ERR(key_ref);
1705 ret = key_get_type_from_user(type, _type, sizeof(type));
1709 restriction = strndup_user(_restriction, PAGE_SIZE);
1710 if (IS_ERR(restriction)) {
1711 ret = PTR_ERR(restriction);
1719 ret = keyring_restrict(key_ref, _type ? type : NULL, restriction);
1722 key_ref_put(key_ref);
1727 * Get keyrings subsystem capabilities.
1729 long keyctl_capabilities(unsigned char __user *_buffer, size_t buflen)
1731 size_t size = buflen;
1734 if (size > sizeof(keyrings_capabilities))
1735 size = sizeof(keyrings_capabilities);
1736 if (copy_to_user(_buffer, keyrings_capabilities, size) != 0)
1738 if (size < buflen &&
1739 clear_user(_buffer + size, buflen - size) != 0)
1743 return sizeof(keyrings_capabilities);
1747 * The key control system call
1749 SYSCALL_DEFINE5(keyctl, int, option, unsigned long, arg2, unsigned long, arg3,
1750 unsigned long, arg4, unsigned long, arg5)
1753 case KEYCTL_GET_KEYRING_ID:
1754 return keyctl_get_keyring_ID((key_serial_t) arg2,
1757 case KEYCTL_JOIN_SESSION_KEYRING:
1758 return keyctl_join_session_keyring((const char __user *) arg2);
1761 return keyctl_update_key((key_serial_t) arg2,
1762 (const void __user *) arg3,
1766 return keyctl_revoke_key((key_serial_t) arg2);
1768 case KEYCTL_DESCRIBE:
1769 return keyctl_describe_key((key_serial_t) arg2,
1770 (char __user *) arg3,
1774 return keyctl_keyring_clear((key_serial_t) arg2);
1777 return keyctl_keyring_link((key_serial_t) arg2,
1778 (key_serial_t) arg3);
1781 return keyctl_keyring_unlink((key_serial_t) arg2,
1782 (key_serial_t) arg3);
1785 return keyctl_keyring_search((key_serial_t) arg2,
1786 (const char __user *) arg3,
1787 (const char __user *) arg4,
1788 (key_serial_t) arg5);
1791 return keyctl_read_key((key_serial_t) arg2,
1792 (char __user *) arg3,
1796 return keyctl_chown_key((key_serial_t) arg2,
1800 case KEYCTL_SETPERM:
1801 return keyctl_setperm_key((key_serial_t) arg2,
1802 (unsigned int)arg3);
1804 case KEYCTL_INSTANTIATE:
1805 return keyctl_instantiate_key((key_serial_t) arg2,
1806 (const void __user *) arg3,
1808 (key_serial_t) arg5);
1811 return keyctl_negate_key((key_serial_t) arg2,
1813 (key_serial_t) arg4);
1815 case KEYCTL_SET_REQKEY_KEYRING:
1816 return keyctl_set_reqkey_keyring(arg2);
1818 case KEYCTL_SET_TIMEOUT:
1819 return keyctl_set_timeout((key_serial_t) arg2,
1822 case KEYCTL_ASSUME_AUTHORITY:
1823 return keyctl_assume_authority((key_serial_t) arg2);
1825 case KEYCTL_GET_SECURITY:
1826 return keyctl_get_security((key_serial_t) arg2,
1827 (char __user *) arg3,
1830 case KEYCTL_SESSION_TO_PARENT:
1831 return keyctl_session_to_parent();
1834 return keyctl_reject_key((key_serial_t) arg2,
1837 (key_serial_t) arg5);
1839 case KEYCTL_INSTANTIATE_IOV:
1840 return keyctl_instantiate_key_iov(
1841 (key_serial_t) arg2,
1842 (const struct iovec __user *) arg3,
1844 (key_serial_t) arg5);
1846 case KEYCTL_INVALIDATE:
1847 return keyctl_invalidate_key((key_serial_t) arg2);
1849 case KEYCTL_GET_PERSISTENT:
1850 return keyctl_get_persistent((uid_t)arg2, (key_serial_t)arg3);
1852 case KEYCTL_DH_COMPUTE:
1853 return keyctl_dh_compute((struct keyctl_dh_params __user *) arg2,
1854 (char __user *) arg3, (size_t) arg4,
1855 (struct keyctl_kdf_params __user *) arg5);
1857 case KEYCTL_RESTRICT_KEYRING:
1858 return keyctl_restrict_keyring((key_serial_t) arg2,
1859 (const char __user *) arg3,
1860 (const char __user *) arg4);
1862 case KEYCTL_PKEY_QUERY:
1865 return keyctl_pkey_query((key_serial_t)arg2,
1866 (const char __user *)arg4,
1867 (struct keyctl_pkey_query __user *)arg5);
1869 case KEYCTL_PKEY_ENCRYPT:
1870 case KEYCTL_PKEY_DECRYPT:
1871 case KEYCTL_PKEY_SIGN:
1872 return keyctl_pkey_e_d_s(
1874 (const struct keyctl_pkey_params __user *)arg2,
1875 (const char __user *)arg3,
1876 (const void __user *)arg4,
1877 (void __user *)arg5);
1879 case KEYCTL_PKEY_VERIFY:
1880 return keyctl_pkey_verify(
1881 (const struct keyctl_pkey_params __user *)arg2,
1882 (const char __user *)arg3,
1883 (const void __user *)arg4,
1884 (const void __user *)arg5);
1887 return keyctl_keyring_move((key_serial_t)arg2,
1890 (unsigned int)arg5);
1891 case KEYCTL_GRANT_PERMISSION:
1892 return keyctl_grant_permission((key_serial_t)arg2,
1893 (enum key_ace_subject_type)arg3,
1895 (unsigned int)arg5);
1897 case KEYCTL_CAPABILITIES:
1898 return keyctl_capabilities((unsigned char __user *)arg2, (size_t)arg3);