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/slab.h>
16 #include <linux/syscalls.h>
17 #include <linux/key.h>
18 #include <linux/keyctl.h>
20 #include <linux/capability.h>
21 #include <linux/string.h>
22 #include <linux/err.h>
23 #include <linux/vmalloc.h>
24 #include <linux/security.h>
25 #include <asm/uaccess.h>
28 static int key_get_type_from_user(char *type,
29 const char __user *_type,
34 ret = strncpy_from_user(type, _type, len);
37 if (ret == 0 || ret >= len)
46 * Extract the description of a new key from userspace and either add it as a
47 * new key to the specified keyring or update a matching key in that keyring.
49 * If the description is NULL or an empty string, the key type is asked to
50 * generate one from the payload.
52 * The keyring must be writable so that we can attach the key to it.
54 * If successful, the new key's serial number is returned, otherwise an error
57 SYSCALL_DEFINE5(add_key, const char __user *, _type,
58 const char __user *, _description,
59 const void __user *, _payload,
63 key_ref_t keyring_ref, key_ref;
64 char type[32], *description;
70 if (plen > 1024 * 1024 - 1)
73 /* draw all the data into kernel space */
74 ret = key_get_type_from_user(type, _type, sizeof(type));
80 description = strndup_user(_description, PAGE_SIZE);
81 if (IS_ERR(description)) {
82 ret = PTR_ERR(description);
91 /* pull the payload in if one was supplied */
97 payload = kmalloc(plen, GFP_KERNEL | __GFP_NOWARN);
99 if (plen <= PAGE_SIZE)
102 payload = vmalloc(plen);
108 if (copy_from_user(payload, _payload, plen) != 0)
112 /* find the target keyring (which must be writable) */
113 keyring_ref = lookup_user_key(ringid, KEY_LOOKUP_CREATE, KEY_WRITE);
114 if (IS_ERR(keyring_ref)) {
115 ret = PTR_ERR(keyring_ref);
119 /* create or update the requested key and add it to the target
121 key_ref = key_create_or_update(keyring_ref, type, description,
122 payload, plen, KEY_PERM_UNDEF,
124 if (!IS_ERR(key_ref)) {
125 ret = key_ref_to_ptr(key_ref)->serial;
126 key_ref_put(key_ref);
129 ret = PTR_ERR(key_ref);
132 key_ref_put(keyring_ref);
145 * Search the process keyrings and keyring trees linked from those for a
146 * matching key. Keyrings must have appropriate Search permission to be
149 * If a key is found, it will be attached to the destination keyring if there's
150 * one specified and the serial number of the key will be returned.
152 * If no key is found, /sbin/request-key will be invoked if _callout_info is
153 * non-NULL in an attempt to create a key. The _callout_info string will be
154 * passed to /sbin/request-key to aid with completing the request. If the
155 * _callout_info string is "" then it will be changed to "-".
157 SYSCALL_DEFINE4(request_key, const char __user *, _type,
158 const char __user *, _description,
159 const char __user *, _callout_info,
160 key_serial_t, destringid)
162 struct key_type *ktype;
166 char type[32], *description, *callout_info;
169 /* pull the type into kernel space */
170 ret = key_get_type_from_user(type, _type, sizeof(type));
174 /* pull the description into kernel space */
175 description = strndup_user(_description, PAGE_SIZE);
176 if (IS_ERR(description)) {
177 ret = PTR_ERR(description);
181 /* pull the callout info into kernel space */
185 callout_info = strndup_user(_callout_info, PAGE_SIZE);
186 if (IS_ERR(callout_info)) {
187 ret = PTR_ERR(callout_info);
190 callout_len = strlen(callout_info);
193 /* get the destination keyring if specified */
196 dest_ref = lookup_user_key(destringid, KEY_LOOKUP_CREATE,
198 if (IS_ERR(dest_ref)) {
199 ret = PTR_ERR(dest_ref);
204 /* find the key type */
205 ktype = key_type_lookup(type);
207 ret = PTR_ERR(ktype);
212 key = request_key_and_link(ktype, description, callout_info,
213 callout_len, NULL, key_ref_to_ptr(dest_ref),
220 /* wait for the key to finish being constructed */
221 ret = wait_for_key_construction(key, 1);
232 key_ref_put(dest_ref);
242 * Get the ID of the specified process keyring.
244 * The requested keyring must have search permission to be found.
246 * If successful, the ID of the requested keyring will be returned.
248 long keyctl_get_keyring_ID(key_serial_t id, int create)
251 unsigned long lflags;
254 lflags = create ? KEY_LOOKUP_CREATE : 0;
255 key_ref = lookup_user_key(id, lflags, KEY_SEARCH);
256 if (IS_ERR(key_ref)) {
257 ret = PTR_ERR(key_ref);
261 ret = key_ref_to_ptr(key_ref)->serial;
262 key_ref_put(key_ref);
268 * Join a (named) session keyring.
270 * Create and join an anonymous session keyring or join a named session
271 * keyring, creating it if necessary. A named session keyring must have Search
272 * permission for it to be joined. Session keyrings without this permit will
275 * If successful, the ID of the joined session keyring will be returned.
277 long keyctl_join_session_keyring(const char __user *_name)
282 /* fetch the name from userspace */
285 name = strndup_user(_name, PAGE_SIZE);
292 /* join the session */
293 ret = join_session_keyring(name);
301 * Update a key's data payload from the given data.
303 * The key must grant the caller Write permission and the key type must support
304 * updating for this to work. A negative key can be positively instantiated
307 * If successful, 0 will be returned. If the key type does not support
308 * updating, then -EOPNOTSUPP will be returned.
310 long keyctl_update_key(key_serial_t id,
311 const void __user *_payload,
319 if (plen > PAGE_SIZE)
322 /* pull the payload in if one was supplied */
326 payload = kmalloc(plen, GFP_KERNEL);
331 if (copy_from_user(payload, _payload, plen) != 0)
335 /* find the target key (which must be writable) */
336 key_ref = lookup_user_key(id, 0, KEY_WRITE);
337 if (IS_ERR(key_ref)) {
338 ret = PTR_ERR(key_ref);
343 ret = key_update(key_ref, payload, plen);
345 key_ref_put(key_ref);
355 * The key must be grant the caller Write or Setattr permission for this to
356 * work. The key type should give up its quota claim when revoked. The key
357 * and any links to the key will be automatically garbage collected after a
358 * certain amount of time (/proc/sys/kernel/keys/gc_delay).
360 * If successful, 0 is returned.
362 long keyctl_revoke_key(key_serial_t id)
367 key_ref = lookup_user_key(id, 0, KEY_WRITE);
368 if (IS_ERR(key_ref)) {
369 ret = PTR_ERR(key_ref);
372 key_ref = lookup_user_key(id, 0, KEY_SETATTR);
373 if (IS_ERR(key_ref)) {
374 ret = PTR_ERR(key_ref);
379 key_revoke(key_ref_to_ptr(key_ref));
382 key_ref_put(key_ref);
390 * The key must be grant the caller Invalidate permission for this to work.
391 * The key and any links to the key will be automatically garbage collected
394 * If successful, 0 is returned.
396 long keyctl_invalidate_key(key_serial_t id)
403 key_ref = lookup_user_key(id, 0, KEY_SEARCH);
404 if (IS_ERR(key_ref)) {
405 ret = PTR_ERR(key_ref);
409 key_invalidate(key_ref_to_ptr(key_ref));
412 key_ref_put(key_ref);
414 kleave(" = %ld", ret);
419 * Clear the specified keyring, creating an empty process keyring if one of the
420 * special keyring IDs is used.
422 * The keyring must grant the caller Write permission for this to work. If
423 * successful, 0 will be returned.
425 long keyctl_keyring_clear(key_serial_t ringid)
427 key_ref_t keyring_ref;
430 keyring_ref = lookup_user_key(ringid, KEY_LOOKUP_CREATE, KEY_WRITE);
431 if (IS_ERR(keyring_ref)) {
432 ret = PTR_ERR(keyring_ref);
434 /* Root is permitted to invalidate certain special keyrings */
435 if (capable(CAP_SYS_ADMIN)) {
436 keyring_ref = lookup_user_key(ringid, 0, 0);
437 if (IS_ERR(keyring_ref))
439 if (test_bit(KEY_FLAG_ROOT_CAN_CLEAR,
440 &key_ref_to_ptr(keyring_ref)->flags))
449 ret = keyring_clear(key_ref_to_ptr(keyring_ref));
451 key_ref_put(keyring_ref);
457 * Create a link from a keyring to a key if there's no matching key in the
458 * keyring, otherwise replace the link to the matching key with a link to the
461 * The key must grant the caller Link permission and the the keyring must grant
462 * the caller Write permission. Furthermore, if an additional link is created,
463 * the keyring's quota will be extended.
465 * If successful, 0 will be returned.
467 long keyctl_keyring_link(key_serial_t id, key_serial_t ringid)
469 key_ref_t keyring_ref, key_ref;
472 keyring_ref = lookup_user_key(ringid, KEY_LOOKUP_CREATE, KEY_WRITE);
473 if (IS_ERR(keyring_ref)) {
474 ret = PTR_ERR(keyring_ref);
478 key_ref = lookup_user_key(id, KEY_LOOKUP_CREATE, KEY_LINK);
479 if (IS_ERR(key_ref)) {
480 ret = PTR_ERR(key_ref);
484 ret = key_link(key_ref_to_ptr(keyring_ref), key_ref_to_ptr(key_ref));
486 key_ref_put(key_ref);
488 key_ref_put(keyring_ref);
494 * Unlink a key from a keyring.
496 * The keyring must grant the caller Write permission for this to work; the key
497 * itself need not grant the caller anything. If the last link to a key is
498 * removed then that key will be scheduled for destruction.
500 * If successful, 0 will be returned.
502 long keyctl_keyring_unlink(key_serial_t id, key_serial_t ringid)
504 key_ref_t keyring_ref, key_ref;
507 keyring_ref = lookup_user_key(ringid, 0, KEY_WRITE);
508 if (IS_ERR(keyring_ref)) {
509 ret = PTR_ERR(keyring_ref);
513 key_ref = lookup_user_key(id, KEY_LOOKUP_FOR_UNLINK, 0);
514 if (IS_ERR(key_ref)) {
515 ret = PTR_ERR(key_ref);
519 ret = key_unlink(key_ref_to_ptr(keyring_ref), key_ref_to_ptr(key_ref));
521 key_ref_put(key_ref);
523 key_ref_put(keyring_ref);
529 * Return a description of a key to userspace.
531 * The key must grant the caller View permission for this to work.
533 * If there's a buffer, we place up to buflen bytes of data into it formatted
534 * in the following way:
536 * type;uid;gid;perm;description<NUL>
538 * If successful, we return the amount of description available, irrespective
539 * of how much we may have copied into the buffer.
541 long keyctl_describe_key(key_serial_t keyid,
545 struct key *key, *instkey;
550 key_ref = lookup_user_key(keyid, KEY_LOOKUP_PARTIAL, KEY_VIEW);
551 if (IS_ERR(key_ref)) {
552 /* viewing a key under construction is permitted if we have the
553 * authorisation token handy */
554 if (PTR_ERR(key_ref) == -EACCES) {
555 instkey = key_get_instantiation_authkey(keyid);
556 if (!IS_ERR(instkey)) {
558 key_ref = lookup_user_key(keyid,
561 if (!IS_ERR(key_ref))
566 ret = PTR_ERR(key_ref);
571 /* calculate how much description we're going to return */
573 tmpbuf = kmalloc(PAGE_SIZE, GFP_KERNEL);
577 key = key_ref_to_ptr(key_ref);
579 ret = snprintf(tmpbuf, PAGE_SIZE - 1,
585 key->description ?: "");
587 /* include a NUL char at the end of the data */
588 if (ret > PAGE_SIZE - 1)
593 /* consider returning the data */
594 if (buffer && buflen > 0) {
598 if (copy_to_user(buffer, tmpbuf, buflen) != 0)
604 key_ref_put(key_ref);
610 * Search the specified keyring and any keyrings it links to for a matching
611 * key. Only keyrings that grant the caller Search permission will be searched
612 * (this includes the starting keyring). Only keys with Search permission can
615 * If successful, the found key will be linked to the destination keyring if
616 * supplied and the key has Link permission, and the found key ID will be
619 long keyctl_keyring_search(key_serial_t ringid,
620 const char __user *_type,
621 const char __user *_description,
622 key_serial_t destringid)
624 struct key_type *ktype;
625 key_ref_t keyring_ref, key_ref, dest_ref;
626 char type[32], *description;
629 /* pull the type and description into kernel space */
630 ret = key_get_type_from_user(type, _type, sizeof(type));
634 description = strndup_user(_description, PAGE_SIZE);
635 if (IS_ERR(description)) {
636 ret = PTR_ERR(description);
640 /* get the keyring at which to begin the search */
641 keyring_ref = lookup_user_key(ringid, 0, KEY_SEARCH);
642 if (IS_ERR(keyring_ref)) {
643 ret = PTR_ERR(keyring_ref);
647 /* get the destination keyring if specified */
650 dest_ref = lookup_user_key(destringid, KEY_LOOKUP_CREATE,
652 if (IS_ERR(dest_ref)) {
653 ret = PTR_ERR(dest_ref);
658 /* find the key type */
659 ktype = key_type_lookup(type);
661 ret = PTR_ERR(ktype);
666 key_ref = keyring_search(keyring_ref, ktype, description);
667 if (IS_ERR(key_ref)) {
668 ret = PTR_ERR(key_ref);
670 /* treat lack or presence of a negative key the same */
676 /* link the resulting key to the destination keyring if we can */
678 ret = key_permission(key_ref, KEY_LINK);
682 ret = key_link(key_ref_to_ptr(dest_ref), key_ref_to_ptr(key_ref));
687 ret = key_ref_to_ptr(key_ref)->serial;
690 key_ref_put(key_ref);
694 key_ref_put(dest_ref);
696 key_ref_put(keyring_ref);
704 * Read a key's payload.
706 * The key must either grant the caller Read permission, or it must grant the
707 * caller Search permission when searched for from the process keyrings.
709 * If successful, we place up to buflen bytes of data into the buffer, if one
710 * is provided, and return the amount of data that is available in the key,
711 * irrespective of how much we copied into the buffer.
713 long keyctl_read_key(key_serial_t keyid, char __user *buffer, size_t buflen)
719 /* find the key first */
720 key_ref = lookup_user_key(keyid, 0, 0);
721 if (IS_ERR(key_ref)) {
726 key = key_ref_to_ptr(key_ref);
728 /* see if we can read it directly */
729 ret = key_permission(key_ref, KEY_READ);
735 /* we can't; see if it's searchable from this process's keyrings
736 * - we automatically take account of the fact that it may be
737 * dangling off an instantiation key
739 if (!is_key_possessed(key_ref)) {
744 /* the key is probably readable - now try to read it */
746 ret = key_validate(key);
749 if (key->type->read) {
750 /* read the data with the semaphore held (since we
752 down_read(&key->sem);
753 ret = key->type->read(key, buffer, buflen);
765 * Change the ownership of a key
767 * The key must grant the caller Setattr permission for this to work, though
768 * the key need not be fully instantiated yet. For the UID to be changed, or
769 * for the GID to be changed to a group the caller is not a member of, the
770 * caller must have sysadmin capability. If either uid or gid is -1 then that
771 * attribute is not changed.
773 * If the UID is to be changed, the new user must have sufficient quota to
774 * accept the key. The quota deduction will be removed from the old user to
775 * the new user should the attribute be changed.
777 * If successful, 0 will be returned.
779 long keyctl_chown_key(key_serial_t id, uid_t uid, gid_t gid)
781 struct key_user *newowner, *zapowner = NULL;
787 if (uid == (uid_t) -1 && gid == (gid_t) -1)
790 key_ref = lookup_user_key(id, KEY_LOOKUP_CREATE | KEY_LOOKUP_PARTIAL,
792 if (IS_ERR(key_ref)) {
793 ret = PTR_ERR(key_ref);
797 key = key_ref_to_ptr(key_ref);
799 /* make the changes with the locks held to prevent chown/chown races */
801 down_write(&key->sem);
803 if (!capable(CAP_SYS_ADMIN)) {
804 /* only the sysadmin can chown a key to some other UID */
805 if (uid != (uid_t) -1 && key->uid != uid)
808 /* only the sysadmin can set the key's GID to a group other
809 * than one of those that the current process subscribes to */
810 if (gid != (gid_t) -1 && gid != key->gid && !in_group_p(gid))
815 if (uid != (uid_t) -1 && uid != key->uid) {
817 newowner = key_user_lookup(uid, current_user_ns());
821 /* transfer the quota burden to the new user */
822 if (test_bit(KEY_FLAG_IN_QUOTA, &key->flags)) {
823 unsigned maxkeys = (uid == 0) ?
824 key_quota_root_maxkeys : key_quota_maxkeys;
825 unsigned maxbytes = (uid == 0) ?
826 key_quota_root_maxbytes : key_quota_maxbytes;
828 spin_lock(&newowner->lock);
829 if (newowner->qnkeys + 1 >= maxkeys ||
830 newowner->qnbytes + key->quotalen >= maxbytes ||
831 newowner->qnbytes + key->quotalen <
836 newowner->qnbytes += key->quotalen;
837 spin_unlock(&newowner->lock);
839 spin_lock(&key->user->lock);
841 key->user->qnbytes -= key->quotalen;
842 spin_unlock(&key->user->lock);
845 atomic_dec(&key->user->nkeys);
846 atomic_inc(&newowner->nkeys);
848 if (test_bit(KEY_FLAG_INSTANTIATED, &key->flags)) {
849 atomic_dec(&key->user->nikeys);
850 atomic_inc(&newowner->nikeys);
853 zapowner = key->user;
854 key->user = newowner;
859 if (gid != (gid_t) -1)
868 key_user_put(zapowner);
873 spin_unlock(&newowner->lock);
880 * Change the permission mask on a key.
882 * The key must grant the caller Setattr permission for this to work, though
883 * the key need not be fully instantiated yet. If the caller does not have
884 * sysadmin capability, it may only change the permission on keys that it owns.
886 long keyctl_setperm_key(key_serial_t id, key_perm_t perm)
893 if (perm & ~(KEY_POS_ALL | KEY_USR_ALL | KEY_GRP_ALL | KEY_OTH_ALL))
896 key_ref = lookup_user_key(id, KEY_LOOKUP_CREATE | KEY_LOOKUP_PARTIAL,
898 if (IS_ERR(key_ref)) {
899 ret = PTR_ERR(key_ref);
903 key = key_ref_to_ptr(key_ref);
905 /* make the changes with the locks held to prevent chown/chmod races */
907 down_write(&key->sem);
909 /* if we're not the sysadmin, we can only change a key that we own */
910 if (capable(CAP_SYS_ADMIN) || key->uid == current_fsuid()) {
922 * Get the destination keyring for instantiation and check that the caller has
923 * Write permission on it.
925 static long get_instantiation_keyring(key_serial_t ringid,
926 struct request_key_auth *rka,
927 struct key **_dest_keyring)
931 *_dest_keyring = NULL;
933 /* just return a NULL pointer if we weren't asked to make a link */
937 /* if a specific keyring is nominated by ID, then use that */
939 dkref = lookup_user_key(ringid, KEY_LOOKUP_CREATE, KEY_WRITE);
941 return PTR_ERR(dkref);
942 *_dest_keyring = key_ref_to_ptr(dkref);
946 if (ringid == KEY_SPEC_REQKEY_AUTH_KEY)
949 /* otherwise specify the destination keyring recorded in the
950 * authorisation key (any KEY_SPEC_*_KEYRING) */
951 if (ringid >= KEY_SPEC_REQUESTOR_KEYRING) {
952 *_dest_keyring = key_get(rka->dest_keyring);
960 * Change the request_key authorisation key on the current process.
962 static int keyctl_change_reqkey_auth(struct key *key)
966 new = prepare_creds();
970 key_put(new->request_key_auth);
971 new->request_key_auth = key_get(key);
973 return commit_creds(new);
977 * Copy the iovec data from userspace
979 static long copy_from_user_iovec(void *buffer, const struct iovec *iov,
982 for (; ioc > 0; ioc--) {
983 if (copy_from_user(buffer, iov->iov_base, iov->iov_len) != 0)
985 buffer += iov->iov_len;
992 * Instantiate a key with the specified payload and link the key into the
993 * destination keyring if one is given.
995 * The caller must have the appropriate instantiation permit set for this to
996 * work (see keyctl_assume_authority). No other permissions are required.
998 * If successful, 0 will be returned.
1000 long keyctl_instantiate_key_common(key_serial_t id,
1001 const struct iovec *payload_iov,
1004 key_serial_t ringid)
1006 const struct cred *cred = current_cred();
1007 struct request_key_auth *rka;
1008 struct key *instkey, *dest_keyring;
1013 kenter("%d,,%zu,%d", id, plen, ringid);
1016 if (plen > 1024 * 1024 - 1)
1019 /* the appropriate instantiation authorisation key must have been
1020 * assumed before calling this */
1022 instkey = cred->request_key_auth;
1026 rka = instkey->payload.data;
1027 if (rka->target_key->serial != id)
1030 /* pull the payload in if one was supplied */
1035 payload = kmalloc(plen, GFP_KERNEL);
1037 if (plen <= PAGE_SIZE)
1040 payload = vmalloc(plen);
1045 ret = copy_from_user_iovec(payload, payload_iov, ioc);
1050 /* find the destination keyring amongst those belonging to the
1051 * requesting task */
1052 ret = get_instantiation_keyring(ringid, rka, &dest_keyring);
1056 /* instantiate the key and link it into a keyring */
1057 ret = key_instantiate_and_link(rka->target_key, payload, plen,
1058 dest_keyring, instkey);
1060 key_put(dest_keyring);
1062 /* discard the assumed authority if it's just been disabled by
1063 * instantiation of the key */
1065 keyctl_change_reqkey_auth(NULL);
1077 * Instantiate a key with the specified payload and link the key into the
1078 * destination keyring if one is given.
1080 * The caller must have the appropriate instantiation permit set for this to
1081 * work (see keyctl_assume_authority). No other permissions are required.
1083 * If successful, 0 will be returned.
1085 long keyctl_instantiate_key(key_serial_t id,
1086 const void __user *_payload,
1088 key_serial_t ringid)
1090 if (_payload && plen) {
1091 struct iovec iov[1] = {
1092 [0].iov_base = (void __user *)_payload,
1096 return keyctl_instantiate_key_common(id, iov, 1, plen, ringid);
1099 return keyctl_instantiate_key_common(id, NULL, 0, 0, ringid);
1103 * Instantiate a key with the specified multipart payload and link the key into
1104 * the destination keyring if one is given.
1106 * The caller must have the appropriate instantiation permit set for this to
1107 * work (see keyctl_assume_authority). No other permissions are required.
1109 * If successful, 0 will be returned.
1111 long keyctl_instantiate_key_iov(key_serial_t id,
1112 const struct iovec __user *_payload_iov,
1114 key_serial_t ringid)
1116 struct iovec iovstack[UIO_FASTIOV], *iov = iovstack;
1119 if (!_payload_iov || !ioc)
1122 ret = rw_copy_check_uvector(WRITE, _payload_iov, ioc,
1123 ARRAY_SIZE(iovstack), iovstack, &iov);
1127 goto no_payload_free;
1129 ret = keyctl_instantiate_key_common(id, iov, ioc, ret, ringid);
1131 if (iov != iovstack)
1136 if (iov != iovstack)
1139 return keyctl_instantiate_key_common(id, NULL, 0, 0, ringid);
1143 * Negatively instantiate the key with the given timeout (in seconds) and link
1144 * the key into the destination keyring if one is given.
1146 * The caller must have the appropriate instantiation permit set for this to
1147 * work (see keyctl_assume_authority). No other permissions are required.
1149 * The key and any links to the key will be automatically garbage collected
1150 * after the timeout expires.
1152 * Negative keys are used to rate limit repeated request_key() calls by causing
1153 * them to return -ENOKEY until the negative key expires.
1155 * If successful, 0 will be returned.
1157 long keyctl_negate_key(key_serial_t id, unsigned timeout, key_serial_t ringid)
1159 return keyctl_reject_key(id, timeout, ENOKEY, ringid);
1163 * Negatively instantiate the key with the given timeout (in seconds) and error
1164 * code and link the key into the destination keyring if one is given.
1166 * The caller must have the appropriate instantiation permit set for this to
1167 * work (see keyctl_assume_authority). No other permissions are required.
1169 * The key and any links to the key will be automatically garbage collected
1170 * after the timeout expires.
1172 * Negative keys are used to rate limit repeated request_key() calls by causing
1173 * them to return the specified error code until the negative key expires.
1175 * If successful, 0 will be returned.
1177 long keyctl_reject_key(key_serial_t id, unsigned timeout, unsigned error,
1178 key_serial_t ringid)
1180 const struct cred *cred = current_cred();
1181 struct request_key_auth *rka;
1182 struct key *instkey, *dest_keyring;
1185 kenter("%d,%u,%u,%d", id, timeout, error, ringid);
1187 /* must be a valid error code and mustn't be a kernel special */
1189 error >= MAX_ERRNO ||
1190 error == ERESTARTSYS ||
1191 error == ERESTARTNOINTR ||
1192 error == ERESTARTNOHAND ||
1193 error == ERESTART_RESTARTBLOCK)
1196 /* the appropriate instantiation authorisation key must have been
1197 * assumed before calling this */
1199 instkey = cred->request_key_auth;
1203 rka = instkey->payload.data;
1204 if (rka->target_key->serial != id)
1207 /* find the destination keyring if present (which must also be
1209 ret = get_instantiation_keyring(ringid, rka, &dest_keyring);
1213 /* instantiate the key and link it into a keyring */
1214 ret = key_reject_and_link(rka->target_key, timeout, error,
1215 dest_keyring, instkey);
1217 key_put(dest_keyring);
1219 /* discard the assumed authority if it's just been disabled by
1220 * instantiation of the key */
1222 keyctl_change_reqkey_auth(NULL);
1229 * Read or set the default keyring in which request_key() will cache keys and
1230 * return the old setting.
1232 * If a process keyring is specified then this will be created if it doesn't
1233 * yet exist. The old setting will be returned if successful.
1235 long keyctl_set_reqkey_keyring(int reqkey_defl)
1238 int ret, old_setting;
1240 old_setting = current_cred_xxx(jit_keyring);
1242 if (reqkey_defl == KEY_REQKEY_DEFL_NO_CHANGE)
1245 new = prepare_creds();
1249 switch (reqkey_defl) {
1250 case KEY_REQKEY_DEFL_THREAD_KEYRING:
1251 ret = install_thread_keyring_to_cred(new);
1256 case KEY_REQKEY_DEFL_PROCESS_KEYRING:
1257 ret = install_process_keyring_to_cred(new);
1265 case KEY_REQKEY_DEFL_DEFAULT:
1266 case KEY_REQKEY_DEFL_SESSION_KEYRING:
1267 case KEY_REQKEY_DEFL_USER_KEYRING:
1268 case KEY_REQKEY_DEFL_USER_SESSION_KEYRING:
1269 case KEY_REQKEY_DEFL_REQUESTOR_KEYRING:
1272 case KEY_REQKEY_DEFL_NO_CHANGE:
1273 case KEY_REQKEY_DEFL_GROUP_KEYRING:
1280 new->jit_keyring = reqkey_defl;
1289 * Set or clear the timeout on a key.
1291 * Either the key must grant the caller Setattr permission or else the caller
1292 * must hold an instantiation authorisation token for the key.
1294 * The timeout is either 0 to clear the timeout, or a number of seconds from
1295 * the current time. The key and any links to the key will be automatically
1296 * garbage collected after the timeout expires.
1298 * If successful, 0 is returned.
1300 long keyctl_set_timeout(key_serial_t id, unsigned timeout)
1302 struct key *key, *instkey;
1306 key_ref = lookup_user_key(id, KEY_LOOKUP_CREATE | KEY_LOOKUP_PARTIAL,
1308 if (IS_ERR(key_ref)) {
1309 /* setting the timeout on a key under construction is permitted
1310 * if we have the authorisation token handy */
1311 if (PTR_ERR(key_ref) == -EACCES) {
1312 instkey = key_get_instantiation_authkey(id);
1313 if (!IS_ERR(instkey)) {
1315 key_ref = lookup_user_key(id,
1318 if (!IS_ERR(key_ref))
1323 ret = PTR_ERR(key_ref);
1328 key = key_ref_to_ptr(key_ref);
1329 key_set_timeout(key, timeout);
1338 * Assume (or clear) the authority to instantiate the specified key.
1340 * This sets the authoritative token currently in force for key instantiation.
1341 * This must be done for a key to be instantiated. It has the effect of making
1342 * available all the keys from the caller of the request_key() that created a
1343 * key to request_key() calls made by the caller of this function.
1345 * The caller must have the instantiation key in their process keyrings with a
1346 * Search permission grant available to the caller.
1348 * If the ID given is 0, then the setting will be cleared and 0 returned.
1350 * If the ID given has a matching an authorisation key, then that key will be
1351 * set and its ID will be returned. The authorisation key can be read to get
1352 * the callout information passed to request_key().
1354 long keyctl_assume_authority(key_serial_t id)
1356 struct key *authkey;
1359 /* special key IDs aren't permitted */
1364 /* we divest ourselves of authority if given an ID of 0 */
1366 ret = keyctl_change_reqkey_auth(NULL);
1370 /* attempt to assume the authority temporarily granted to us whilst we
1371 * instantiate the specified key
1372 * - the authorisation key must be in the current task's keyrings
1375 authkey = key_get_instantiation_authkey(id);
1376 if (IS_ERR(authkey)) {
1377 ret = PTR_ERR(authkey);
1381 ret = keyctl_change_reqkey_auth(authkey);
1386 ret = authkey->serial;
1392 * Get a key's the LSM security label.
1394 * The key must grant the caller View permission for this to work.
1396 * If there's a buffer, then up to buflen bytes of data will be placed into it.
1398 * If successful, the amount of information available will be returned,
1399 * irrespective of how much was copied (including the terminal NUL).
1401 long keyctl_get_security(key_serial_t keyid,
1402 char __user *buffer,
1405 struct key *key, *instkey;
1410 key_ref = lookup_user_key(keyid, KEY_LOOKUP_PARTIAL, KEY_VIEW);
1411 if (IS_ERR(key_ref)) {
1412 if (PTR_ERR(key_ref) != -EACCES)
1413 return PTR_ERR(key_ref);
1415 /* viewing a key under construction is also permitted if we
1416 * have the authorisation token handy */
1417 instkey = key_get_instantiation_authkey(keyid);
1418 if (IS_ERR(instkey))
1419 return PTR_ERR(instkey);
1422 key_ref = lookup_user_key(keyid, KEY_LOOKUP_PARTIAL, 0);
1423 if (IS_ERR(key_ref))
1424 return PTR_ERR(key_ref);
1427 key = key_ref_to_ptr(key_ref);
1428 ret = security_key_getsecurity(key, &context);
1430 /* if no information was returned, give userspace an empty
1433 if (buffer && buflen > 0 &&
1434 copy_to_user(buffer, "", 1) != 0)
1436 } else if (ret > 0) {
1437 /* return as much data as there's room for */
1438 if (buffer && buflen > 0) {
1442 if (copy_to_user(buffer, context, buflen) != 0)
1449 key_ref_put(key_ref);
1454 * Attempt to install the calling process's session keyring on the process's
1457 * The keyring must exist and must grant the caller LINK permission, and the
1458 * parent process must be single-threaded and must have the same effective
1459 * ownership as this process and mustn't be SUID/SGID.
1461 * The keyring will be emplaced on the parent when it next resumes userspace.
1463 * If successful, 0 will be returned.
1465 long keyctl_session_to_parent(void)
1467 struct task_struct *me, *parent;
1468 const struct cred *mycred, *pcred;
1469 struct callback_head *newwork, *oldwork;
1470 key_ref_t keyring_r;
1474 keyring_r = lookup_user_key(KEY_SPEC_SESSION_KEYRING, 0, KEY_LINK);
1475 if (IS_ERR(keyring_r))
1476 return PTR_ERR(keyring_r);
1480 /* our parent is going to need a new cred struct, a new tgcred struct
1481 * and new security data, so we allocate them here to prevent ENOMEM in
1483 cred = cred_alloc_blank();
1486 newwork = &cred->rcu;
1488 cred->tgcred->session_keyring = key_ref_to_ptr(keyring_r);
1489 init_task_work(newwork, key_change_session_keyring);
1493 write_lock_irq(&tasklist_lock);
1497 parent = me->real_parent;
1500 /* the parent mustn't be init and mustn't be a kernel thread */
1501 if (parent->pid <= 1 || !parent->mm)
1504 /* the parent must be single threaded */
1505 if (!thread_group_empty(parent))
1508 /* the parent and the child must have different session keyrings or
1509 * there's no point */
1510 mycred = current_cred();
1511 pcred = __task_cred(parent);
1512 if (mycred == pcred ||
1513 mycred->tgcred->session_keyring == pcred->tgcred->session_keyring) {
1518 /* the parent must have the same effective ownership and mustn't be
1520 if (pcred->uid != mycred->euid ||
1521 pcred->euid != mycred->euid ||
1522 pcred->suid != mycred->euid ||
1523 pcred->gid != mycred->egid ||
1524 pcred->egid != mycred->egid ||
1525 pcred->sgid != mycred->egid)
1528 /* the keyrings must have the same UID */
1529 if ((pcred->tgcred->session_keyring &&
1530 pcred->tgcred->session_keyring->uid != mycred->euid) ||
1531 mycred->tgcred->session_keyring->uid != mycred->euid)
1534 /* cancel an already pending keyring replacement */
1535 oldwork = task_work_cancel(parent, key_change_session_keyring);
1537 /* the replacement session keyring is applied just prior to userspace
1539 ret = task_work_add(parent, newwork, true);
1543 task_unlock(parent);
1544 write_unlock_irq(&tasklist_lock);
1547 put_cred(container_of(oldwork, struct cred, rcu));
1553 key_ref_put(keyring_r);
1558 * The key control system call
1560 SYSCALL_DEFINE5(keyctl, int, option, unsigned long, arg2, unsigned long, arg3,
1561 unsigned long, arg4, unsigned long, arg5)
1564 case KEYCTL_GET_KEYRING_ID:
1565 return keyctl_get_keyring_ID((key_serial_t) arg2,
1568 case KEYCTL_JOIN_SESSION_KEYRING:
1569 return keyctl_join_session_keyring((const char __user *) arg2);
1572 return keyctl_update_key((key_serial_t) arg2,
1573 (const void __user *) arg3,
1577 return keyctl_revoke_key((key_serial_t) arg2);
1579 case KEYCTL_DESCRIBE:
1580 return keyctl_describe_key((key_serial_t) arg2,
1581 (char __user *) arg3,
1585 return keyctl_keyring_clear((key_serial_t) arg2);
1588 return keyctl_keyring_link((key_serial_t) arg2,
1589 (key_serial_t) arg3);
1592 return keyctl_keyring_unlink((key_serial_t) arg2,
1593 (key_serial_t) arg3);
1596 return keyctl_keyring_search((key_serial_t) arg2,
1597 (const char __user *) arg3,
1598 (const char __user *) arg4,
1599 (key_serial_t) arg5);
1602 return keyctl_read_key((key_serial_t) arg2,
1603 (char __user *) arg3,
1607 return keyctl_chown_key((key_serial_t) arg2,
1611 case KEYCTL_SETPERM:
1612 return keyctl_setperm_key((key_serial_t) arg2,
1615 case KEYCTL_INSTANTIATE:
1616 return keyctl_instantiate_key((key_serial_t) arg2,
1617 (const void __user *) arg3,
1619 (key_serial_t) arg5);
1622 return keyctl_negate_key((key_serial_t) arg2,
1624 (key_serial_t) arg4);
1626 case KEYCTL_SET_REQKEY_KEYRING:
1627 return keyctl_set_reqkey_keyring(arg2);
1629 case KEYCTL_SET_TIMEOUT:
1630 return keyctl_set_timeout((key_serial_t) arg2,
1633 case KEYCTL_ASSUME_AUTHORITY:
1634 return keyctl_assume_authority((key_serial_t) arg2);
1636 case KEYCTL_GET_SECURITY:
1637 return keyctl_get_security((key_serial_t) arg2,
1638 (char __user *) arg3,
1641 case KEYCTL_SESSION_TO_PARENT:
1642 return keyctl_session_to_parent();
1645 return keyctl_reject_key((key_serial_t) arg2,
1648 (key_serial_t) arg5);
1650 case KEYCTL_INSTANTIATE_IOV:
1651 return keyctl_instantiate_key_iov(
1652 (key_serial_t) arg2,
1653 (const struct iovec __user *) arg3,
1655 (key_serial_t) arg5);
1657 case KEYCTL_INVALIDATE:
1658 return keyctl_invalidate_key((key_serial_t) arg2);