1 /* Userspace key control operations
3 * Copyright (C) 2004-5 Red Hat, Inc. All Rights Reserved.
4 * Written by David Howells (dhowells@redhat.com)
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public License
8 * as published by the Free Software Foundation; either version
9 * 2 of the License, or (at your option) any later version.
12 #include <linux/module.h>
13 #include <linux/init.h>
14 #include <linux/sched.h>
15 #include <linux/sched/task.h>
16 #include <linux/slab.h>
17 #include <linux/syscalls.h>
18 #include <linux/key.h>
19 #include <linux/keyctl.h>
21 #include <linux/capability.h>
22 #include <linux/cred.h>
23 #include <linux/string.h>
24 #include <linux/err.h>
25 #include <linux/vmalloc.h>
26 #include <linux/security.h>
27 #include <linux/uio.h>
28 #include <linux/uaccess.h>
31 #define KEY_MAX_DESC_SIZE 4096
33 static int key_get_type_from_user(char *type,
34 const char __user *_type,
39 ret = strncpy_from_user(type, _type, len);
42 if (ret == 0 || ret >= len)
51 * Extract the description of a new key from userspace and either add it as a
52 * new key to the specified keyring or update a matching key in that keyring.
54 * If the description is NULL or an empty string, the key type is asked to
55 * generate one from the payload.
57 * The keyring must be writable so that we can attach the key to it.
59 * If successful, the new key's serial number is returned, otherwise an error
62 SYSCALL_DEFINE5(add_key, const char __user *, _type,
63 const char __user *, _description,
64 const void __user *, _payload,
68 key_ref_t keyring_ref, key_ref;
69 char type[32], *description;
74 if (plen > 1024 * 1024 - 1)
77 /* draw all the data into kernel space */
78 ret = key_get_type_from_user(type, _type, sizeof(type));
84 description = strndup_user(_description, KEY_MAX_DESC_SIZE);
85 if (IS_ERR(description)) {
86 ret = PTR_ERR(description);
92 } else if ((description[0] == '.') &&
93 (strncmp(type, "keyring", 7) == 0)) {
99 /* pull the payload in if one was supplied */
104 payload = kmalloc(plen, GFP_KERNEL | __GFP_NOWARN);
106 if (plen <= PAGE_SIZE)
108 payload = vmalloc(plen);
114 if (copy_from_user(payload, _payload, plen) != 0)
118 /* find the target keyring (which must be writable) */
119 keyring_ref = lookup_user_key(ringid, KEY_LOOKUP_CREATE, KEY_NEED_WRITE);
120 if (IS_ERR(keyring_ref)) {
121 ret = PTR_ERR(keyring_ref);
125 /* create or update the requested key and add it to the target
127 key_ref = key_create_or_update(keyring_ref, type, description,
128 payload, plen, KEY_PERM_UNDEF,
130 if (!IS_ERR(key_ref)) {
131 ret = key_ref_to_ptr(key_ref)->serial;
132 key_ref_put(key_ref);
135 ret = PTR_ERR(key_ref);
138 key_ref_put(keyring_ref);
148 * Search the process keyrings and keyring trees linked from those for a
149 * matching key. Keyrings must have appropriate Search permission to be
152 * If a key is found, it will be attached to the destination keyring if there's
153 * one specified and the serial number of the key will be returned.
155 * If no key is found, /sbin/request-key will be invoked if _callout_info is
156 * non-NULL in an attempt to create a key. The _callout_info string will be
157 * passed to /sbin/request-key to aid with completing the request. If the
158 * _callout_info string is "" then it will be changed to "-".
160 SYSCALL_DEFINE4(request_key, const char __user *, _type,
161 const char __user *, _description,
162 const char __user *, _callout_info,
163 key_serial_t, destringid)
165 struct key_type *ktype;
169 char type[32], *description, *callout_info;
172 /* pull the type into kernel space */
173 ret = key_get_type_from_user(type, _type, sizeof(type));
177 /* pull the description into kernel space */
178 description = strndup_user(_description, KEY_MAX_DESC_SIZE);
179 if (IS_ERR(description)) {
180 ret = PTR_ERR(description);
184 /* pull the callout info into kernel space */
188 callout_info = strndup_user(_callout_info, PAGE_SIZE);
189 if (IS_ERR(callout_info)) {
190 ret = PTR_ERR(callout_info);
193 callout_len = strlen(callout_info);
196 /* get the destination keyring if specified */
199 dest_ref = lookup_user_key(destringid, KEY_LOOKUP_CREATE,
201 if (IS_ERR(dest_ref)) {
202 ret = PTR_ERR(dest_ref);
207 /* find the key type */
208 ktype = key_type_lookup(type);
210 ret = PTR_ERR(ktype);
215 key = request_key_and_link(ktype, description, callout_info,
216 callout_len, NULL, key_ref_to_ptr(dest_ref),
223 /* wait for the key to finish being constructed */
224 ret = wait_for_key_construction(key, 1);
235 key_ref_put(dest_ref);
245 * Get the ID of the specified process keyring.
247 * The requested keyring must have search permission to be found.
249 * If successful, the ID of the requested keyring will be returned.
251 long keyctl_get_keyring_ID(key_serial_t id, int create)
254 unsigned long lflags;
257 lflags = create ? KEY_LOOKUP_CREATE : 0;
258 key_ref = lookup_user_key(id, lflags, KEY_NEED_SEARCH);
259 if (IS_ERR(key_ref)) {
260 ret = PTR_ERR(key_ref);
264 ret = key_ref_to_ptr(key_ref)->serial;
265 key_ref_put(key_ref);
271 * Join a (named) session keyring.
273 * Create and join an anonymous session keyring or join a named session
274 * keyring, creating it if necessary. A named session keyring must have Search
275 * permission for it to be joined. Session keyrings without this permit will
276 * be skipped over. It is not permitted for userspace to create or join
277 * keyrings whose name begin with a dot.
279 * If successful, the ID of the joined session keyring will be returned.
281 long keyctl_join_session_keyring(const char __user *_name)
286 /* fetch the name from userspace */
289 name = strndup_user(_name, KEY_MAX_DESC_SIZE);
300 /* join the session */
301 ret = join_session_keyring(name);
309 * Update a key's data payload from the given data.
311 * The key must grant the caller Write permission and the key type must support
312 * updating for this to work. A negative key can be positively instantiated
315 * If successful, 0 will be returned. If the key type does not support
316 * updating, then -EOPNOTSUPP will be returned.
318 long keyctl_update_key(key_serial_t id,
319 const void __user *_payload,
327 if (plen > PAGE_SIZE)
330 /* pull the payload in if one was supplied */
334 payload = kmalloc(plen, GFP_KERNEL);
339 if (copy_from_user(payload, _payload, plen) != 0)
343 /* find the target key (which must be writable) */
344 key_ref = lookup_user_key(id, 0, KEY_NEED_WRITE);
345 if (IS_ERR(key_ref)) {
346 ret = PTR_ERR(key_ref);
351 ret = key_update(key_ref, payload, plen);
353 key_ref_put(key_ref);
363 * The key must be grant the caller Write or Setattr permission for this to
364 * work. The key type should give up its quota claim when revoked. The key
365 * and any links to the key will be automatically garbage collected after a
366 * certain amount of time (/proc/sys/kernel/keys/gc_delay).
368 * Keys with KEY_FLAG_KEEP set should not be revoked.
370 * If successful, 0 is returned.
372 long keyctl_revoke_key(key_serial_t id)
378 key_ref = lookup_user_key(id, 0, KEY_NEED_WRITE);
379 if (IS_ERR(key_ref)) {
380 ret = PTR_ERR(key_ref);
383 key_ref = lookup_user_key(id, 0, KEY_NEED_SETATTR);
384 if (IS_ERR(key_ref)) {
385 ret = PTR_ERR(key_ref);
390 key = key_ref_to_ptr(key_ref);
392 if (test_bit(KEY_FLAG_KEEP, &key->flags))
397 key_ref_put(key_ref);
405 * The key must be grant the caller Invalidate permission for this to work.
406 * The key and any links to the key will be automatically garbage collected
409 * Keys with KEY_FLAG_KEEP set should not be invalidated.
411 * If successful, 0 is returned.
413 long keyctl_invalidate_key(key_serial_t id)
421 key_ref = lookup_user_key(id, 0, KEY_NEED_SEARCH);
422 if (IS_ERR(key_ref)) {
423 ret = PTR_ERR(key_ref);
425 /* Root is permitted to invalidate certain special keys */
426 if (capable(CAP_SYS_ADMIN)) {
427 key_ref = lookup_user_key(id, 0, 0);
430 if (test_bit(KEY_FLAG_ROOT_CAN_INVAL,
431 &key_ref_to_ptr(key_ref)->flags))
440 key = key_ref_to_ptr(key_ref);
442 if (test_bit(KEY_FLAG_KEEP, &key->flags))
447 key_ref_put(key_ref);
449 kleave(" = %ld", ret);
454 * Clear the specified keyring, creating an empty process keyring if one of the
455 * special keyring IDs is used.
457 * The keyring must grant the caller Write permission and not have
458 * KEY_FLAG_KEEP set for this to work. If successful, 0 will be returned.
460 long keyctl_keyring_clear(key_serial_t ringid)
462 key_ref_t keyring_ref;
466 keyring_ref = lookup_user_key(ringid, KEY_LOOKUP_CREATE, KEY_NEED_WRITE);
467 if (IS_ERR(keyring_ref)) {
468 ret = PTR_ERR(keyring_ref);
470 /* Root is permitted to invalidate certain special keyrings */
471 if (capable(CAP_SYS_ADMIN)) {
472 keyring_ref = lookup_user_key(ringid, 0, 0);
473 if (IS_ERR(keyring_ref))
475 if (test_bit(KEY_FLAG_ROOT_CAN_CLEAR,
476 &key_ref_to_ptr(keyring_ref)->flags))
485 keyring = key_ref_to_ptr(keyring_ref);
486 if (test_bit(KEY_FLAG_KEEP, &keyring->flags))
489 ret = keyring_clear(keyring);
491 key_ref_put(keyring_ref);
497 * Create a link from a keyring to a key if there's no matching key in the
498 * keyring, otherwise replace the link to the matching key with a link to the
501 * The key must grant the caller Link permission and the the keyring must grant
502 * the caller Write permission. Furthermore, if an additional link is created,
503 * the keyring's quota will be extended.
505 * If successful, 0 will be returned.
507 long keyctl_keyring_link(key_serial_t id, key_serial_t ringid)
509 key_ref_t keyring_ref, key_ref;
512 keyring_ref = lookup_user_key(ringid, KEY_LOOKUP_CREATE, KEY_NEED_WRITE);
513 if (IS_ERR(keyring_ref)) {
514 ret = PTR_ERR(keyring_ref);
518 key_ref = lookup_user_key(id, KEY_LOOKUP_CREATE, KEY_NEED_LINK);
519 if (IS_ERR(key_ref)) {
520 ret = PTR_ERR(key_ref);
524 ret = key_link(key_ref_to_ptr(keyring_ref), key_ref_to_ptr(key_ref));
526 key_ref_put(key_ref);
528 key_ref_put(keyring_ref);
534 * Unlink a key from a keyring.
536 * The keyring must grant the caller Write permission for this to work; the key
537 * itself need not grant the caller anything. If the last link to a key is
538 * removed then that key will be scheduled for destruction.
540 * Keys or keyrings with KEY_FLAG_KEEP set should not be unlinked.
542 * If successful, 0 will be returned.
544 long keyctl_keyring_unlink(key_serial_t id, key_serial_t ringid)
546 key_ref_t keyring_ref, key_ref;
547 struct key *keyring, *key;
550 keyring_ref = lookup_user_key(ringid, 0, KEY_NEED_WRITE);
551 if (IS_ERR(keyring_ref)) {
552 ret = PTR_ERR(keyring_ref);
556 key_ref = lookup_user_key(id, KEY_LOOKUP_FOR_UNLINK, 0);
557 if (IS_ERR(key_ref)) {
558 ret = PTR_ERR(key_ref);
562 keyring = key_ref_to_ptr(keyring_ref);
563 key = key_ref_to_ptr(key_ref);
564 if (test_bit(KEY_FLAG_KEEP, &keyring->flags) &&
565 test_bit(KEY_FLAG_KEEP, &key->flags))
568 ret = key_unlink(keyring, key);
570 key_ref_put(key_ref);
572 key_ref_put(keyring_ref);
578 * Return a description of a key to userspace.
580 * The key must grant the caller View permission for this to work.
582 * If there's a buffer, we place up to buflen bytes of data into it formatted
583 * in the following way:
585 * type;uid;gid;perm;description<NUL>
587 * If successful, we return the amount of description available, irrespective
588 * of how much we may have copied into the buffer.
590 long keyctl_describe_key(key_serial_t keyid,
594 struct key *key, *instkey;
598 int desclen, infolen;
600 key_ref = lookup_user_key(keyid, KEY_LOOKUP_PARTIAL, KEY_NEED_VIEW);
601 if (IS_ERR(key_ref)) {
602 /* viewing a key under construction is permitted if we have the
603 * authorisation token handy */
604 if (PTR_ERR(key_ref) == -EACCES) {
605 instkey = key_get_instantiation_authkey(keyid);
606 if (!IS_ERR(instkey)) {
608 key_ref = lookup_user_key(keyid,
611 if (!IS_ERR(key_ref))
616 ret = PTR_ERR(key_ref);
621 key = key_ref_to_ptr(key_ref);
622 desclen = strlen(key->description);
624 /* calculate how much information we're going to return */
626 infobuf = kasprintf(GFP_KERNEL,
629 from_kuid_munged(current_user_ns(), key->uid),
630 from_kgid_munged(current_user_ns(), key->gid),
634 infolen = strlen(infobuf);
635 ret = infolen + desclen + 1;
637 /* consider returning the data */
638 if (buffer && buflen >= ret) {
639 if (copy_to_user(buffer, infobuf, infolen) != 0 ||
640 copy_to_user(buffer + infolen, key->description,
647 key_ref_put(key_ref);
653 * Search the specified keyring and any keyrings it links to for a matching
654 * key. Only keyrings that grant the caller Search permission will be searched
655 * (this includes the starting keyring). Only keys with Search permission can
658 * If successful, the found key will be linked to the destination keyring if
659 * supplied and the key has Link permission, and the found key ID will be
662 long keyctl_keyring_search(key_serial_t ringid,
663 const char __user *_type,
664 const char __user *_description,
665 key_serial_t destringid)
667 struct key_type *ktype;
668 key_ref_t keyring_ref, key_ref, dest_ref;
669 char type[32], *description;
672 /* pull the type and description into kernel space */
673 ret = key_get_type_from_user(type, _type, sizeof(type));
677 description = strndup_user(_description, KEY_MAX_DESC_SIZE);
678 if (IS_ERR(description)) {
679 ret = PTR_ERR(description);
683 /* get the keyring at which to begin the search */
684 keyring_ref = lookup_user_key(ringid, 0, KEY_NEED_SEARCH);
685 if (IS_ERR(keyring_ref)) {
686 ret = PTR_ERR(keyring_ref);
690 /* get the destination keyring if specified */
693 dest_ref = lookup_user_key(destringid, KEY_LOOKUP_CREATE,
695 if (IS_ERR(dest_ref)) {
696 ret = PTR_ERR(dest_ref);
701 /* find the key type */
702 ktype = key_type_lookup(type);
704 ret = PTR_ERR(ktype);
709 key_ref = keyring_search(keyring_ref, ktype, description);
710 if (IS_ERR(key_ref)) {
711 ret = PTR_ERR(key_ref);
713 /* treat lack or presence of a negative key the same */
719 /* link the resulting key to the destination keyring if we can */
721 ret = key_permission(key_ref, KEY_NEED_LINK);
725 ret = key_link(key_ref_to_ptr(dest_ref), key_ref_to_ptr(key_ref));
730 ret = key_ref_to_ptr(key_ref)->serial;
733 key_ref_put(key_ref);
737 key_ref_put(dest_ref);
739 key_ref_put(keyring_ref);
747 * Read a key's payload.
749 * The key must either grant the caller Read permission, or it must grant the
750 * caller Search permission when searched for from the process keyrings.
752 * If successful, we place up to buflen bytes of data into the buffer, if one
753 * is provided, and return the amount of data that is available in the key,
754 * irrespective of how much we copied into the buffer.
756 long keyctl_read_key(key_serial_t keyid, char __user *buffer, size_t buflen)
762 /* find the key first */
763 key_ref = lookup_user_key(keyid, 0, 0);
764 if (IS_ERR(key_ref)) {
769 key = key_ref_to_ptr(key_ref);
771 /* see if we can read it directly */
772 ret = key_permission(key_ref, KEY_NEED_READ);
778 /* we can't; see if it's searchable from this process's keyrings
779 * - we automatically take account of the fact that it may be
780 * dangling off an instantiation key
782 if (!is_key_possessed(key_ref)) {
787 /* the key is probably readable - now try to read it */
790 if (key->type->read) {
791 /* Read the data with the semaphore held (since we might sleep)
792 * to protect against the key being updated or revoked.
794 down_read(&key->sem);
795 ret = key_validate(key);
797 ret = key->type->read(key, buffer, buflen);
808 * Change the ownership of a key
810 * The key must grant the caller Setattr permission for this to work, though
811 * the key need not be fully instantiated yet. For the UID to be changed, or
812 * for the GID to be changed to a group the caller is not a member of, the
813 * caller must have sysadmin capability. If either uid or gid is -1 then that
814 * attribute is not changed.
816 * If the UID is to be changed, the new user must have sufficient quota to
817 * accept the key. The quota deduction will be removed from the old user to
818 * the new user should the attribute be changed.
820 * If successful, 0 will be returned.
822 long keyctl_chown_key(key_serial_t id, uid_t user, gid_t group)
824 struct key_user *newowner, *zapowner = NULL;
831 uid = make_kuid(current_user_ns(), user);
832 gid = make_kgid(current_user_ns(), group);
834 if ((user != (uid_t) -1) && !uid_valid(uid))
836 if ((group != (gid_t) -1) && !gid_valid(gid))
840 if (user == (uid_t) -1 && group == (gid_t) -1)
843 key_ref = lookup_user_key(id, KEY_LOOKUP_CREATE | KEY_LOOKUP_PARTIAL,
845 if (IS_ERR(key_ref)) {
846 ret = PTR_ERR(key_ref);
850 key = key_ref_to_ptr(key_ref);
852 /* make the changes with the locks held to prevent chown/chown races */
854 down_write(&key->sem);
856 if (!capable(CAP_SYS_ADMIN)) {
857 /* only the sysadmin can chown a key to some other UID */
858 if (user != (uid_t) -1 && !uid_eq(key->uid, uid))
861 /* only the sysadmin can set the key's GID to a group other
862 * than one of those that the current process subscribes to */
863 if (group != (gid_t) -1 && !gid_eq(gid, key->gid) && !in_group_p(gid))
868 if (user != (uid_t) -1 && !uid_eq(uid, key->uid)) {
870 newowner = key_user_lookup(uid);
874 /* transfer the quota burden to the new user */
875 if (test_bit(KEY_FLAG_IN_QUOTA, &key->flags)) {
876 unsigned maxkeys = uid_eq(uid, GLOBAL_ROOT_UID) ?
877 key_quota_root_maxkeys : key_quota_maxkeys;
878 unsigned maxbytes = uid_eq(uid, GLOBAL_ROOT_UID) ?
879 key_quota_root_maxbytes : key_quota_maxbytes;
881 spin_lock(&newowner->lock);
882 if (newowner->qnkeys + 1 >= maxkeys ||
883 newowner->qnbytes + key->quotalen >= maxbytes ||
884 newowner->qnbytes + key->quotalen <
889 newowner->qnbytes += key->quotalen;
890 spin_unlock(&newowner->lock);
892 spin_lock(&key->user->lock);
894 key->user->qnbytes -= key->quotalen;
895 spin_unlock(&key->user->lock);
898 atomic_dec(&key->user->nkeys);
899 atomic_inc(&newowner->nkeys);
901 if (test_bit(KEY_FLAG_INSTANTIATED, &key->flags)) {
902 atomic_dec(&key->user->nikeys);
903 atomic_inc(&newowner->nikeys);
906 zapowner = key->user;
907 key->user = newowner;
912 if (group != (gid_t) -1)
921 key_user_put(zapowner);
926 spin_unlock(&newowner->lock);
933 * Change the permission mask on a key.
935 * The key must grant the caller Setattr permission for this to work, though
936 * the key need not be fully instantiated yet. If the caller does not have
937 * sysadmin capability, it may only change the permission on keys that it owns.
939 long keyctl_setperm_key(key_serial_t id, key_perm_t perm)
946 if (perm & ~(KEY_POS_ALL | KEY_USR_ALL | KEY_GRP_ALL | KEY_OTH_ALL))
949 key_ref = lookup_user_key(id, KEY_LOOKUP_CREATE | KEY_LOOKUP_PARTIAL,
951 if (IS_ERR(key_ref)) {
952 ret = PTR_ERR(key_ref);
956 key = key_ref_to_ptr(key_ref);
958 /* make the changes with the locks held to prevent chown/chmod races */
960 down_write(&key->sem);
962 /* if we're not the sysadmin, we can only change a key that we own */
963 if (capable(CAP_SYS_ADMIN) || uid_eq(key->uid, current_fsuid())) {
975 * Get the destination keyring for instantiation and check that the caller has
976 * Write permission on it.
978 static long get_instantiation_keyring(key_serial_t ringid,
979 struct request_key_auth *rka,
980 struct key **_dest_keyring)
984 *_dest_keyring = NULL;
986 /* just return a NULL pointer if we weren't asked to make a link */
990 /* if a specific keyring is nominated by ID, then use that */
992 dkref = lookup_user_key(ringid, KEY_LOOKUP_CREATE, KEY_NEED_WRITE);
994 return PTR_ERR(dkref);
995 *_dest_keyring = key_ref_to_ptr(dkref);
999 if (ringid == KEY_SPEC_REQKEY_AUTH_KEY)
1002 /* otherwise specify the destination keyring recorded in the
1003 * authorisation key (any KEY_SPEC_*_KEYRING) */
1004 if (ringid >= KEY_SPEC_REQUESTOR_KEYRING) {
1005 *_dest_keyring = key_get(rka->dest_keyring);
1013 * Change the request_key authorisation key on the current process.
1015 static int keyctl_change_reqkey_auth(struct key *key)
1019 new = prepare_creds();
1023 key_put(new->request_key_auth);
1024 new->request_key_auth = key_get(key);
1026 return commit_creds(new);
1030 * Instantiate a key with the specified payload and link the key into the
1031 * destination keyring if one is given.
1033 * The caller must have the appropriate instantiation permit set for this to
1034 * work (see keyctl_assume_authority). No other permissions are required.
1036 * If successful, 0 will be returned.
1038 long keyctl_instantiate_key_common(key_serial_t id,
1039 struct iov_iter *from,
1040 key_serial_t ringid)
1042 const struct cred *cred = current_cred();
1043 struct request_key_auth *rka;
1044 struct key *instkey, *dest_keyring;
1045 size_t plen = from ? iov_iter_count(from) : 0;
1049 kenter("%d,,%zu,%d", id, plen, ringid);
1055 if (plen > 1024 * 1024 - 1)
1058 /* the appropriate instantiation authorisation key must have been
1059 * assumed before calling this */
1061 instkey = cred->request_key_auth;
1065 rka = instkey->payload.data[0];
1066 if (rka->target_key->serial != id)
1069 /* pull the payload in if one was supplied */
1074 payload = kmalloc(plen, GFP_KERNEL);
1076 if (plen <= PAGE_SIZE)
1078 payload = vmalloc(plen);
1084 if (!copy_from_iter_full(payload, plen, from))
1088 /* find the destination keyring amongst those belonging to the
1089 * requesting task */
1090 ret = get_instantiation_keyring(ringid, rka, &dest_keyring);
1094 /* instantiate the key and link it into a keyring */
1095 ret = key_instantiate_and_link(rka->target_key, payload, plen,
1096 dest_keyring, instkey);
1098 key_put(dest_keyring);
1100 /* discard the assumed authority if it's just been disabled by
1101 * instantiation of the key */
1103 keyctl_change_reqkey_auth(NULL);
1112 * Instantiate a key with the specified payload and link the key into the
1113 * destination keyring if one is given.
1115 * The caller must have the appropriate instantiation permit set for this to
1116 * work (see keyctl_assume_authority). No other permissions are required.
1118 * If successful, 0 will be returned.
1120 long keyctl_instantiate_key(key_serial_t id,
1121 const void __user *_payload,
1123 key_serial_t ringid)
1125 if (_payload && plen) {
1127 struct iov_iter from;
1130 ret = import_single_range(WRITE, (void __user *)_payload, plen,
1135 return keyctl_instantiate_key_common(id, &from, ringid);
1138 return keyctl_instantiate_key_common(id, NULL, ringid);
1142 * Instantiate a key with the specified multipart payload and link the key into
1143 * the destination keyring if one is given.
1145 * The caller must have the appropriate instantiation permit set for this to
1146 * work (see keyctl_assume_authority). No other permissions are required.
1148 * If successful, 0 will be returned.
1150 long keyctl_instantiate_key_iov(key_serial_t id,
1151 const struct iovec __user *_payload_iov,
1153 key_serial_t ringid)
1155 struct iovec iovstack[UIO_FASTIOV], *iov = iovstack;
1156 struct iov_iter from;
1162 ret = import_iovec(WRITE, _payload_iov, ioc,
1163 ARRAY_SIZE(iovstack), &iov, &from);
1166 ret = keyctl_instantiate_key_common(id, &from, ringid);
1172 * Negatively instantiate the key with the given timeout (in seconds) and link
1173 * the key into the destination keyring if one is given.
1175 * The caller must have the appropriate instantiation permit set for this to
1176 * work (see keyctl_assume_authority). No other permissions are required.
1178 * The key and any links to the key will be automatically garbage collected
1179 * after the timeout expires.
1181 * Negative keys are used to rate limit repeated request_key() calls by causing
1182 * them to return -ENOKEY until the negative key expires.
1184 * If successful, 0 will be returned.
1186 long keyctl_negate_key(key_serial_t id, unsigned timeout, key_serial_t ringid)
1188 return keyctl_reject_key(id, timeout, ENOKEY, ringid);
1192 * Negatively instantiate the key with the given timeout (in seconds) and error
1193 * code and link the key into the destination keyring if one is given.
1195 * The caller must have the appropriate instantiation permit set for this to
1196 * work (see keyctl_assume_authority). No other permissions are required.
1198 * The key and any links to the key will be automatically garbage collected
1199 * after the timeout expires.
1201 * Negative keys are used to rate limit repeated request_key() calls by causing
1202 * them to return the specified error code until the negative key expires.
1204 * If successful, 0 will be returned.
1206 long keyctl_reject_key(key_serial_t id, unsigned timeout, unsigned error,
1207 key_serial_t ringid)
1209 const struct cred *cred = current_cred();
1210 struct request_key_auth *rka;
1211 struct key *instkey, *dest_keyring;
1214 kenter("%d,%u,%u,%d", id, timeout, error, ringid);
1216 /* must be a valid error code and mustn't be a kernel special */
1218 error >= MAX_ERRNO ||
1219 error == ERESTARTSYS ||
1220 error == ERESTARTNOINTR ||
1221 error == ERESTARTNOHAND ||
1222 error == ERESTART_RESTARTBLOCK)
1225 /* the appropriate instantiation authorisation key must have been
1226 * assumed before calling this */
1228 instkey = cred->request_key_auth;
1232 rka = instkey->payload.data[0];
1233 if (rka->target_key->serial != id)
1236 /* find the destination keyring if present (which must also be
1238 ret = get_instantiation_keyring(ringid, rka, &dest_keyring);
1242 /* instantiate the key and link it into a keyring */
1243 ret = key_reject_and_link(rka->target_key, timeout, error,
1244 dest_keyring, instkey);
1246 key_put(dest_keyring);
1248 /* discard the assumed authority if it's just been disabled by
1249 * instantiation of the key */
1251 keyctl_change_reqkey_auth(NULL);
1258 * Read or set the default keyring in which request_key() will cache keys and
1259 * return the old setting.
1261 * If a thread or process keyring is specified then it will be created if it
1262 * doesn't yet exist. The old setting will be returned if successful.
1264 long keyctl_set_reqkey_keyring(int reqkey_defl)
1267 int ret, old_setting;
1269 old_setting = current_cred_xxx(jit_keyring);
1271 if (reqkey_defl == KEY_REQKEY_DEFL_NO_CHANGE)
1274 new = prepare_creds();
1278 switch (reqkey_defl) {
1279 case KEY_REQKEY_DEFL_THREAD_KEYRING:
1280 ret = install_thread_keyring_to_cred(new);
1285 case KEY_REQKEY_DEFL_PROCESS_KEYRING:
1286 ret = install_process_keyring_to_cred(new);
1291 case KEY_REQKEY_DEFL_DEFAULT:
1292 case KEY_REQKEY_DEFL_SESSION_KEYRING:
1293 case KEY_REQKEY_DEFL_USER_KEYRING:
1294 case KEY_REQKEY_DEFL_USER_SESSION_KEYRING:
1295 case KEY_REQKEY_DEFL_REQUESTOR_KEYRING:
1298 case KEY_REQKEY_DEFL_NO_CHANGE:
1299 case KEY_REQKEY_DEFL_GROUP_KEYRING:
1306 new->jit_keyring = reqkey_defl;
1315 * Set or clear the timeout on a key.
1317 * Either the key must grant the caller Setattr permission or else the caller
1318 * must hold an instantiation authorisation token for the key.
1320 * The timeout is either 0 to clear the timeout, or a number of seconds from
1321 * the current time. The key and any links to the key will be automatically
1322 * garbage collected after the timeout expires.
1324 * Keys with KEY_FLAG_KEEP set should not be timed out.
1326 * If successful, 0 is returned.
1328 long keyctl_set_timeout(key_serial_t id, unsigned timeout)
1330 struct key *key, *instkey;
1334 key_ref = lookup_user_key(id, KEY_LOOKUP_CREATE | KEY_LOOKUP_PARTIAL,
1336 if (IS_ERR(key_ref)) {
1337 /* setting the timeout on a key under construction is permitted
1338 * if we have the authorisation token handy */
1339 if (PTR_ERR(key_ref) == -EACCES) {
1340 instkey = key_get_instantiation_authkey(id);
1341 if (!IS_ERR(instkey)) {
1343 key_ref = lookup_user_key(id,
1346 if (!IS_ERR(key_ref))
1351 ret = PTR_ERR(key_ref);
1356 key = key_ref_to_ptr(key_ref);
1358 if (test_bit(KEY_FLAG_KEEP, &key->flags))
1361 key_set_timeout(key, timeout);
1369 * Assume (or clear) the authority to instantiate the specified key.
1371 * This sets the authoritative token currently in force for key instantiation.
1372 * This must be done for a key to be instantiated. It has the effect of making
1373 * available all the keys from the caller of the request_key() that created a
1374 * key to request_key() calls made by the caller of this function.
1376 * The caller must have the instantiation key in their process keyrings with a
1377 * Search permission grant available to the caller.
1379 * If the ID given is 0, then the setting will be cleared and 0 returned.
1381 * If the ID given has a matching an authorisation key, then that key will be
1382 * set and its ID will be returned. The authorisation key can be read to get
1383 * the callout information passed to request_key().
1385 long keyctl_assume_authority(key_serial_t id)
1387 struct key *authkey;
1390 /* special key IDs aren't permitted */
1395 /* we divest ourselves of authority if given an ID of 0 */
1397 ret = keyctl_change_reqkey_auth(NULL);
1401 /* attempt to assume the authority temporarily granted to us whilst we
1402 * instantiate the specified key
1403 * - the authorisation key must be in the current task's keyrings
1406 authkey = key_get_instantiation_authkey(id);
1407 if (IS_ERR(authkey)) {
1408 ret = PTR_ERR(authkey);
1412 ret = keyctl_change_reqkey_auth(authkey);
1417 ret = authkey->serial;
1423 * Get a key's the LSM security label.
1425 * The key must grant the caller View permission for this to work.
1427 * If there's a buffer, then up to buflen bytes of data will be placed into it.
1429 * If successful, the amount of information available will be returned,
1430 * irrespective of how much was copied (including the terminal NUL).
1432 long keyctl_get_security(key_serial_t keyid,
1433 char __user *buffer,
1436 struct key *key, *instkey;
1441 key_ref = lookup_user_key(keyid, KEY_LOOKUP_PARTIAL, KEY_NEED_VIEW);
1442 if (IS_ERR(key_ref)) {
1443 if (PTR_ERR(key_ref) != -EACCES)
1444 return PTR_ERR(key_ref);
1446 /* viewing a key under construction is also permitted if we
1447 * have the authorisation token handy */
1448 instkey = key_get_instantiation_authkey(keyid);
1449 if (IS_ERR(instkey))
1450 return PTR_ERR(instkey);
1453 key_ref = lookup_user_key(keyid, KEY_LOOKUP_PARTIAL, 0);
1454 if (IS_ERR(key_ref))
1455 return PTR_ERR(key_ref);
1458 key = key_ref_to_ptr(key_ref);
1459 ret = security_key_getsecurity(key, &context);
1461 /* if no information was returned, give userspace an empty
1464 if (buffer && buflen > 0 &&
1465 copy_to_user(buffer, "", 1) != 0)
1467 } else if (ret > 0) {
1468 /* return as much data as there's room for */
1469 if (buffer && buflen > 0) {
1473 if (copy_to_user(buffer, context, buflen) != 0)
1480 key_ref_put(key_ref);
1485 * Attempt to install the calling process's session keyring on the process's
1488 * The keyring must exist and must grant the caller LINK permission, and the
1489 * parent process must be single-threaded and must have the same effective
1490 * ownership as this process and mustn't be SUID/SGID.
1492 * The keyring will be emplaced on the parent when it next resumes userspace.
1494 * If successful, 0 will be returned.
1496 long keyctl_session_to_parent(void)
1498 struct task_struct *me, *parent;
1499 const struct cred *mycred, *pcred;
1500 struct callback_head *newwork, *oldwork;
1501 key_ref_t keyring_r;
1505 keyring_r = lookup_user_key(KEY_SPEC_SESSION_KEYRING, 0, KEY_NEED_LINK);
1506 if (IS_ERR(keyring_r))
1507 return PTR_ERR(keyring_r);
1511 /* our parent is going to need a new cred struct, a new tgcred struct
1512 * and new security data, so we allocate them here to prevent ENOMEM in
1514 cred = cred_alloc_blank();
1517 newwork = &cred->rcu;
1519 cred->session_keyring = key_ref_to_ptr(keyring_r);
1521 init_task_work(newwork, key_change_session_keyring);
1525 write_lock_irq(&tasklist_lock);
1529 parent = me->real_parent;
1531 /* the parent mustn't be init and mustn't be a kernel thread */
1532 if (parent->pid <= 1 || !parent->mm)
1535 /* the parent must be single threaded */
1536 if (!thread_group_empty(parent))
1539 /* the parent and the child must have different session keyrings or
1540 * there's no point */
1541 mycred = current_cred();
1542 pcred = __task_cred(parent);
1543 if (mycred == pcred ||
1544 mycred->session_keyring == pcred->session_keyring) {
1549 /* the parent must have the same effective ownership and mustn't be
1551 if (!uid_eq(pcred->uid, mycred->euid) ||
1552 !uid_eq(pcred->euid, mycred->euid) ||
1553 !uid_eq(pcred->suid, mycred->euid) ||
1554 !gid_eq(pcred->gid, mycred->egid) ||
1555 !gid_eq(pcred->egid, mycred->egid) ||
1556 !gid_eq(pcred->sgid, mycred->egid))
1559 /* the keyrings must have the same UID */
1560 if ((pcred->session_keyring &&
1561 !uid_eq(pcred->session_keyring->uid, mycred->euid)) ||
1562 !uid_eq(mycred->session_keyring->uid, mycred->euid))
1565 /* cancel an already pending keyring replacement */
1566 oldwork = task_work_cancel(parent, key_change_session_keyring);
1568 /* the replacement session keyring is applied just prior to userspace
1570 ret = task_work_add(parent, newwork, true);
1574 write_unlock_irq(&tasklist_lock);
1577 put_cred(container_of(oldwork, struct cred, rcu));
1583 key_ref_put(keyring_r);
1588 * Apply a restriction to a given keyring.
1590 * The caller must have Setattr permission to change keyring restrictions.
1592 * The requested type name may be a NULL pointer to reject all attempts
1593 * to link to the keyring. If _type is non-NULL, _restriction can be
1594 * NULL or a pointer to a string describing the restriction. If _type is
1595 * NULL, _restriction must also be NULL.
1597 * Returns 0 if successful.
1599 long keyctl_restrict_keyring(key_serial_t id, const char __user *_type,
1600 const char __user *_restriction)
1603 bool link_reject = !_type;
1605 char *restriction = NULL;
1608 key_ref = lookup_user_key(id, 0, KEY_NEED_SETATTR);
1609 if (IS_ERR(key_ref))
1610 return PTR_ERR(key_ref);
1613 ret = key_get_type_from_user(type, _type, sizeof(type));
1624 restriction = strndup_user(_restriction, PAGE_SIZE);
1625 if (IS_ERR(restriction)) {
1626 ret = PTR_ERR(restriction);
1631 ret = keyring_restrict(key_ref, link_reject ? NULL : type, restriction);
1635 key_ref_put(key_ref);
1641 * The key control system call
1643 SYSCALL_DEFINE5(keyctl, int, option, unsigned long, arg2, unsigned long, arg3,
1644 unsigned long, arg4, unsigned long, arg5)
1647 case KEYCTL_GET_KEYRING_ID:
1648 return keyctl_get_keyring_ID((key_serial_t) arg2,
1651 case KEYCTL_JOIN_SESSION_KEYRING:
1652 return keyctl_join_session_keyring((const char __user *) arg2);
1655 return keyctl_update_key((key_serial_t) arg2,
1656 (const void __user *) arg3,
1660 return keyctl_revoke_key((key_serial_t) arg2);
1662 case KEYCTL_DESCRIBE:
1663 return keyctl_describe_key((key_serial_t) arg2,
1664 (char __user *) arg3,
1668 return keyctl_keyring_clear((key_serial_t) arg2);
1671 return keyctl_keyring_link((key_serial_t) arg2,
1672 (key_serial_t) arg3);
1675 return keyctl_keyring_unlink((key_serial_t) arg2,
1676 (key_serial_t) arg3);
1679 return keyctl_keyring_search((key_serial_t) arg2,
1680 (const char __user *) arg3,
1681 (const char __user *) arg4,
1682 (key_serial_t) arg5);
1685 return keyctl_read_key((key_serial_t) arg2,
1686 (char __user *) arg3,
1690 return keyctl_chown_key((key_serial_t) arg2,
1694 case KEYCTL_SETPERM:
1695 return keyctl_setperm_key((key_serial_t) arg2,
1698 case KEYCTL_INSTANTIATE:
1699 return keyctl_instantiate_key((key_serial_t) arg2,
1700 (const void __user *) arg3,
1702 (key_serial_t) arg5);
1705 return keyctl_negate_key((key_serial_t) arg2,
1707 (key_serial_t) arg4);
1709 case KEYCTL_SET_REQKEY_KEYRING:
1710 return keyctl_set_reqkey_keyring(arg2);
1712 case KEYCTL_SET_TIMEOUT:
1713 return keyctl_set_timeout((key_serial_t) arg2,
1716 case KEYCTL_ASSUME_AUTHORITY:
1717 return keyctl_assume_authority((key_serial_t) arg2);
1719 case KEYCTL_GET_SECURITY:
1720 return keyctl_get_security((key_serial_t) arg2,
1721 (char __user *) arg3,
1724 case KEYCTL_SESSION_TO_PARENT:
1725 return keyctl_session_to_parent();
1728 return keyctl_reject_key((key_serial_t) arg2,
1731 (key_serial_t) arg5);
1733 case KEYCTL_INSTANTIATE_IOV:
1734 return keyctl_instantiate_key_iov(
1735 (key_serial_t) arg2,
1736 (const struct iovec __user *) arg3,
1738 (key_serial_t) arg5);
1740 case KEYCTL_INVALIDATE:
1741 return keyctl_invalidate_key((key_serial_t) arg2);
1743 case KEYCTL_GET_PERSISTENT:
1744 return keyctl_get_persistent((uid_t)arg2, (key_serial_t)arg3);
1746 case KEYCTL_DH_COMPUTE:
1747 return keyctl_dh_compute((struct keyctl_dh_params __user *) arg2,
1748 (char __user *) arg3, (size_t) arg4,
1749 (struct keyctl_kdf_params __user *) arg5);
1751 case KEYCTL_RESTRICT_KEYRING:
1752 return keyctl_restrict_keyring((key_serial_t) arg2,
1753 (const char __user *) arg3,
1754 (const char __user *) arg4);