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 <linux/uio.h>
26 #include <asm/uaccess.h>
29 static int key_get_type_from_user(char *type,
30 const char __user *_type,
35 ret = strncpy_from_user(type, _type, len);
38 if (ret == 0 || ret >= len)
45 * Extract the description of a new key from userspace and either add it as a
46 * new key to the specified keyring or update a matching key in that keyring.
48 * If the description is NULL or an empty string, the key type is asked to
49 * generate one from the payload.
51 * The keyring must be writable so that we can attach the key to it.
53 * If successful, the new key's serial number is returned, otherwise an error
56 SYSCALL_DEFINE5(add_key, const char __user *, _type,
57 const char __user *, _description,
58 const void __user *, _payload,
62 key_ref_t keyring_ref, key_ref;
63 char type[32], *description;
69 if (plen > 1024 * 1024 - 1)
72 /* draw all the data into kernel space */
73 ret = key_get_type_from_user(type, _type, sizeof(type));
79 description = strndup_user(_description, PAGE_SIZE);
80 if (IS_ERR(description)) {
81 ret = PTR_ERR(description);
87 } else if ((description[0] == '.') &&
88 (strncmp(type, "keyring", 7) == 0)) {
94 /* pull the payload in if one was supplied */
100 payload = kmalloc(plen, GFP_KERNEL | __GFP_NOWARN);
102 if (plen <= PAGE_SIZE)
105 payload = vmalloc(plen);
111 if (copy_from_user(payload, _payload, plen) != 0)
115 /* find the target keyring (which must be writable) */
116 keyring_ref = lookup_user_key(ringid, KEY_LOOKUP_CREATE, KEY_NEED_WRITE);
117 if (IS_ERR(keyring_ref)) {
118 ret = PTR_ERR(keyring_ref);
122 /* create or update the requested key and add it to the target
124 key_ref = key_create_or_update(keyring_ref, type, description,
125 payload, plen, KEY_PERM_UNDEF,
127 if (!IS_ERR(key_ref)) {
128 ret = key_ref_to_ptr(key_ref)->serial;
129 key_ref_put(key_ref);
132 ret = PTR_ERR(key_ref);
135 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, PAGE_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
278 * If successful, the ID of the joined session keyring will be returned.
280 long keyctl_join_session_keyring(const char __user *_name)
285 /* fetch the name from userspace */
288 name = strndup_user(_name, PAGE_SIZE);
295 /* join the session */
296 ret = join_session_keyring(name);
304 * Update a key's data payload from the given data.
306 * The key must grant the caller Write permission and the key type must support
307 * updating for this to work. A negative key can be positively instantiated
310 * If successful, 0 will be returned. If the key type does not support
311 * updating, then -EOPNOTSUPP will be returned.
313 long keyctl_update_key(key_serial_t id,
314 const void __user *_payload,
322 if (plen > PAGE_SIZE)
325 /* pull the payload in if one was supplied */
329 payload = kmalloc(plen, GFP_KERNEL);
334 if (copy_from_user(payload, _payload, plen) != 0)
338 /* find the target key (which must be writable) */
339 key_ref = lookup_user_key(id, 0, KEY_NEED_WRITE);
340 if (IS_ERR(key_ref)) {
341 ret = PTR_ERR(key_ref);
346 ret = key_update(key_ref, payload, plen);
348 key_ref_put(key_ref);
358 * The key must be grant the caller Write or Setattr permission for this to
359 * work. The key type should give up its quota claim when revoked. The key
360 * and any links to the key will be automatically garbage collected after a
361 * certain amount of time (/proc/sys/kernel/keys/gc_delay).
363 * If successful, 0 is returned.
365 long keyctl_revoke_key(key_serial_t id)
370 key_ref = lookup_user_key(id, 0, KEY_NEED_WRITE);
371 if (IS_ERR(key_ref)) {
372 ret = PTR_ERR(key_ref);
375 key_ref = lookup_user_key(id, 0, KEY_NEED_SETATTR);
376 if (IS_ERR(key_ref)) {
377 ret = PTR_ERR(key_ref);
382 key_revoke(key_ref_to_ptr(key_ref));
385 key_ref_put(key_ref);
393 * The key must be grant the caller Invalidate permission for this to work.
394 * The key and any links to the key will be automatically garbage collected
397 * If successful, 0 is returned.
399 long keyctl_invalidate_key(key_serial_t id)
406 key_ref = lookup_user_key(id, 0, KEY_NEED_SEARCH);
407 if (IS_ERR(key_ref)) {
408 ret = PTR_ERR(key_ref);
412 key_invalidate(key_ref_to_ptr(key_ref));
415 key_ref_put(key_ref);
417 kleave(" = %ld", ret);
422 * Clear the specified keyring, creating an empty process keyring if one of the
423 * special keyring IDs is used.
425 * The keyring must grant the caller Write permission for this to work. If
426 * successful, 0 will be returned.
428 long keyctl_keyring_clear(key_serial_t ringid)
430 key_ref_t keyring_ref;
433 keyring_ref = lookup_user_key(ringid, KEY_LOOKUP_CREATE, KEY_NEED_WRITE);
434 if (IS_ERR(keyring_ref)) {
435 ret = PTR_ERR(keyring_ref);
437 /* Root is permitted to invalidate certain special keyrings */
438 if (capable(CAP_SYS_ADMIN)) {
439 keyring_ref = lookup_user_key(ringid, 0, 0);
440 if (IS_ERR(keyring_ref))
442 if (test_bit(KEY_FLAG_ROOT_CAN_CLEAR,
443 &key_ref_to_ptr(keyring_ref)->flags))
452 ret = keyring_clear(key_ref_to_ptr(keyring_ref));
454 key_ref_put(keyring_ref);
460 * Create a link from a keyring to a key if there's no matching key in the
461 * keyring, otherwise replace the link to the matching key with a link to the
464 * The key must grant the caller Link permission and the the keyring must grant
465 * the caller Write permission. Furthermore, if an additional link is created,
466 * the keyring's quota will be extended.
468 * If successful, 0 will be returned.
470 long keyctl_keyring_link(key_serial_t id, key_serial_t ringid)
472 key_ref_t keyring_ref, key_ref;
475 keyring_ref = lookup_user_key(ringid, KEY_LOOKUP_CREATE, KEY_NEED_WRITE);
476 if (IS_ERR(keyring_ref)) {
477 ret = PTR_ERR(keyring_ref);
481 key_ref = lookup_user_key(id, KEY_LOOKUP_CREATE, KEY_NEED_LINK);
482 if (IS_ERR(key_ref)) {
483 ret = PTR_ERR(key_ref);
487 ret = key_link(key_ref_to_ptr(keyring_ref), key_ref_to_ptr(key_ref));
489 key_ref_put(key_ref);
491 key_ref_put(keyring_ref);
497 * Unlink a key from a keyring.
499 * The keyring must grant the caller Write permission for this to work; the key
500 * itself need not grant the caller anything. If the last link to a key is
501 * removed then that key will be scheduled for destruction.
503 * If successful, 0 will be returned.
505 long keyctl_keyring_unlink(key_serial_t id, key_serial_t ringid)
507 key_ref_t keyring_ref, key_ref;
510 keyring_ref = lookup_user_key(ringid, 0, KEY_NEED_WRITE);
511 if (IS_ERR(keyring_ref)) {
512 ret = PTR_ERR(keyring_ref);
516 key_ref = lookup_user_key(id, KEY_LOOKUP_FOR_UNLINK, 0);
517 if (IS_ERR(key_ref)) {
518 ret = PTR_ERR(key_ref);
522 ret = key_unlink(key_ref_to_ptr(keyring_ref), key_ref_to_ptr(key_ref));
524 key_ref_put(key_ref);
526 key_ref_put(keyring_ref);
532 * Return a description of a key to userspace.
534 * The key must grant the caller View permission for this to work.
536 * If there's a buffer, we place up to buflen bytes of data into it formatted
537 * in the following way:
539 * type;uid;gid;perm;description<NUL>
541 * If successful, we return the amount of description available, irrespective
542 * of how much we may have copied into the buffer.
544 long keyctl_describe_key(key_serial_t keyid,
548 struct key *key, *instkey;
553 key_ref = lookup_user_key(keyid, KEY_LOOKUP_PARTIAL, KEY_NEED_VIEW);
554 if (IS_ERR(key_ref)) {
555 /* viewing a key under construction is permitted if we have the
556 * authorisation token handy */
557 if (PTR_ERR(key_ref) == -EACCES) {
558 instkey = key_get_instantiation_authkey(keyid);
559 if (!IS_ERR(instkey)) {
561 key_ref = lookup_user_key(keyid,
564 if (!IS_ERR(key_ref))
569 ret = PTR_ERR(key_ref);
574 /* calculate how much description we're going to return */
576 tmpbuf = kmalloc(PAGE_SIZE, GFP_KERNEL);
580 key = key_ref_to_ptr(key_ref);
582 ret = snprintf(tmpbuf, PAGE_SIZE - 1,
585 from_kuid_munged(current_user_ns(), key->uid),
586 from_kgid_munged(current_user_ns(), key->gid),
588 key->description ?: "");
590 /* include a NUL char at the end of the data */
591 if (ret > PAGE_SIZE - 1)
596 /* consider returning the data */
597 if (buffer && buflen > 0) {
601 if (copy_to_user(buffer, tmpbuf, buflen) != 0)
607 key_ref_put(key_ref);
613 * Search the specified keyring and any keyrings it links to for a matching
614 * key. Only keyrings that grant the caller Search permission will be searched
615 * (this includes the starting keyring). Only keys with Search permission can
618 * If successful, the found key will be linked to the destination keyring if
619 * supplied and the key has Link permission, and the found key ID will be
622 long keyctl_keyring_search(key_serial_t ringid,
623 const char __user *_type,
624 const char __user *_description,
625 key_serial_t destringid)
627 struct key_type *ktype;
628 key_ref_t keyring_ref, key_ref, dest_ref;
629 char type[32], *description;
632 /* pull the type and description into kernel space */
633 ret = key_get_type_from_user(type, _type, sizeof(type));
637 description = strndup_user(_description, PAGE_SIZE);
638 if (IS_ERR(description)) {
639 ret = PTR_ERR(description);
643 /* get the keyring at which to begin the search */
644 keyring_ref = lookup_user_key(ringid, 0, KEY_NEED_SEARCH);
645 if (IS_ERR(keyring_ref)) {
646 ret = PTR_ERR(keyring_ref);
650 /* get the destination keyring if specified */
653 dest_ref = lookup_user_key(destringid, KEY_LOOKUP_CREATE,
655 if (IS_ERR(dest_ref)) {
656 ret = PTR_ERR(dest_ref);
661 /* find the key type */
662 ktype = key_type_lookup(type);
664 ret = PTR_ERR(ktype);
669 key_ref = keyring_search(keyring_ref, ktype, description);
670 if (IS_ERR(key_ref)) {
671 ret = PTR_ERR(key_ref);
673 /* treat lack or presence of a negative key the same */
679 /* link the resulting key to the destination keyring if we can */
681 ret = key_permission(key_ref, KEY_NEED_LINK);
685 ret = key_link(key_ref_to_ptr(dest_ref), key_ref_to_ptr(key_ref));
690 ret = key_ref_to_ptr(key_ref)->serial;
693 key_ref_put(key_ref);
697 key_ref_put(dest_ref);
699 key_ref_put(keyring_ref);
707 * Read a key's payload.
709 * The key must either grant the caller Read permission, or it must grant the
710 * caller Search permission when searched for from the process keyrings.
712 * If successful, we place up to buflen bytes of data into the buffer, if one
713 * is provided, and return the amount of data that is available in the key,
714 * irrespective of how much we copied into the buffer.
716 long keyctl_read_key(key_serial_t keyid, char __user *buffer, size_t buflen)
722 /* find the key first */
723 key_ref = lookup_user_key(keyid, 0, 0);
724 if (IS_ERR(key_ref)) {
729 key = key_ref_to_ptr(key_ref);
731 /* see if we can read it directly */
732 ret = key_permission(key_ref, KEY_NEED_READ);
738 /* we can't; see if it's searchable from this process's keyrings
739 * - we automatically take account of the fact that it may be
740 * dangling off an instantiation key
742 if (!is_key_possessed(key_ref)) {
747 /* the key is probably readable - now try to read it */
749 ret = key_validate(key);
752 if (key->type->read) {
753 /* read the data with the semaphore held (since we
755 down_read(&key->sem);
756 ret = key->type->read(key, buffer, buflen);
768 * Change the ownership of a key
770 * The key must grant the caller Setattr permission for this to work, though
771 * the key need not be fully instantiated yet. For the UID to be changed, or
772 * for the GID to be changed to a group the caller is not a member of, the
773 * caller must have sysadmin capability. If either uid or gid is -1 then that
774 * attribute is not changed.
776 * If the UID is to be changed, the new user must have sufficient quota to
777 * accept the key. The quota deduction will be removed from the old user to
778 * the new user should the attribute be changed.
780 * If successful, 0 will be returned.
782 long keyctl_chown_key(key_serial_t id, uid_t user, gid_t group)
784 struct key_user *newowner, *zapowner = NULL;
791 uid = make_kuid(current_user_ns(), user);
792 gid = make_kgid(current_user_ns(), group);
794 if ((user != (uid_t) -1) && !uid_valid(uid))
796 if ((group != (gid_t) -1) && !gid_valid(gid))
800 if (user == (uid_t) -1 && group == (gid_t) -1)
803 key_ref = lookup_user_key(id, KEY_LOOKUP_CREATE | KEY_LOOKUP_PARTIAL,
805 if (IS_ERR(key_ref)) {
806 ret = PTR_ERR(key_ref);
810 key = key_ref_to_ptr(key_ref);
812 /* make the changes with the locks held to prevent chown/chown races */
814 down_write(&key->sem);
816 if (!capable(CAP_SYS_ADMIN)) {
817 /* only the sysadmin can chown a key to some other UID */
818 if (user != (uid_t) -1 && !uid_eq(key->uid, uid))
821 /* only the sysadmin can set the key's GID to a group other
822 * than one of those that the current process subscribes to */
823 if (group != (gid_t) -1 && !gid_eq(gid, key->gid) && !in_group_p(gid))
828 if (user != (uid_t) -1 && !uid_eq(uid, key->uid)) {
830 newowner = key_user_lookup(uid);
834 /* transfer the quota burden to the new user */
835 if (test_bit(KEY_FLAG_IN_QUOTA, &key->flags)) {
836 unsigned maxkeys = uid_eq(uid, GLOBAL_ROOT_UID) ?
837 key_quota_root_maxkeys : key_quota_maxkeys;
838 unsigned maxbytes = uid_eq(uid, GLOBAL_ROOT_UID) ?
839 key_quota_root_maxbytes : key_quota_maxbytes;
841 spin_lock(&newowner->lock);
842 if (newowner->qnkeys + 1 >= maxkeys ||
843 newowner->qnbytes + key->quotalen >= maxbytes ||
844 newowner->qnbytes + key->quotalen <
849 newowner->qnbytes += key->quotalen;
850 spin_unlock(&newowner->lock);
852 spin_lock(&key->user->lock);
854 key->user->qnbytes -= key->quotalen;
855 spin_unlock(&key->user->lock);
858 atomic_dec(&key->user->nkeys);
859 atomic_inc(&newowner->nkeys);
861 if (test_bit(KEY_FLAG_INSTANTIATED, &key->flags)) {
862 atomic_dec(&key->user->nikeys);
863 atomic_inc(&newowner->nikeys);
866 zapowner = key->user;
867 key->user = newowner;
872 if (group != (gid_t) -1)
881 key_user_put(zapowner);
886 spin_unlock(&newowner->lock);
893 * Change the permission mask on a key.
895 * The key must grant the caller Setattr permission for this to work, though
896 * the key need not be fully instantiated yet. If the caller does not have
897 * sysadmin capability, it may only change the permission on keys that it owns.
899 long keyctl_setperm_key(key_serial_t id, key_perm_t perm)
906 if (perm & ~(KEY_POS_ALL | KEY_USR_ALL | KEY_GRP_ALL | KEY_OTH_ALL))
909 key_ref = lookup_user_key(id, KEY_LOOKUP_CREATE | KEY_LOOKUP_PARTIAL,
911 if (IS_ERR(key_ref)) {
912 ret = PTR_ERR(key_ref);
916 key = key_ref_to_ptr(key_ref);
918 /* make the changes with the locks held to prevent chown/chmod races */
920 down_write(&key->sem);
922 /* if we're not the sysadmin, we can only change a key that we own */
923 if (capable(CAP_SYS_ADMIN) || uid_eq(key->uid, current_fsuid())) {
935 * Get the destination keyring for instantiation and check that the caller has
936 * Write permission on it.
938 static long get_instantiation_keyring(key_serial_t ringid,
939 struct request_key_auth *rka,
940 struct key **_dest_keyring)
944 *_dest_keyring = NULL;
946 /* just return a NULL pointer if we weren't asked to make a link */
950 /* if a specific keyring is nominated by ID, then use that */
952 dkref = lookup_user_key(ringid, KEY_LOOKUP_CREATE, KEY_NEED_WRITE);
954 return PTR_ERR(dkref);
955 *_dest_keyring = key_ref_to_ptr(dkref);
959 if (ringid == KEY_SPEC_REQKEY_AUTH_KEY)
962 /* otherwise specify the destination keyring recorded in the
963 * authorisation key (any KEY_SPEC_*_KEYRING) */
964 if (ringid >= KEY_SPEC_REQUESTOR_KEYRING) {
965 *_dest_keyring = key_get(rka->dest_keyring);
973 * Change the request_key authorisation key on the current process.
975 static int keyctl_change_reqkey_auth(struct key *key)
979 new = prepare_creds();
983 key_put(new->request_key_auth);
984 new->request_key_auth = key_get(key);
986 return commit_creds(new);
990 * Copy the iovec data from userspace
992 static long copy_from_user_iovec(void *buffer, const struct iovec *iov,
995 for (; ioc > 0; ioc--) {
996 if (copy_from_user(buffer, iov->iov_base, iov->iov_len) != 0)
998 buffer += iov->iov_len;
1005 * Instantiate a key with the specified payload and link the key into the
1006 * destination keyring if one is given.
1008 * The caller must have the appropriate instantiation permit set for this to
1009 * work (see keyctl_assume_authority). No other permissions are required.
1011 * If successful, 0 will be returned.
1013 long keyctl_instantiate_key_common(key_serial_t id,
1014 const struct iovec *payload_iov,
1017 key_serial_t ringid)
1019 const struct cred *cred = current_cred();
1020 struct request_key_auth *rka;
1021 struct key *instkey, *dest_keyring;
1026 kenter("%d,,%zu,%d", id, plen, ringid);
1029 if (plen > 1024 * 1024 - 1)
1032 /* the appropriate instantiation authorisation key must have been
1033 * assumed before calling this */
1035 instkey = cred->request_key_auth;
1039 rka = instkey->payload.data;
1040 if (rka->target_key->serial != id)
1043 /* pull the payload in if one was supplied */
1048 payload = kmalloc(plen, GFP_KERNEL);
1050 if (plen <= PAGE_SIZE)
1053 payload = vmalloc(plen);
1058 ret = copy_from_user_iovec(payload, payload_iov, ioc);
1063 /* find the destination keyring amongst those belonging to the
1064 * requesting task */
1065 ret = get_instantiation_keyring(ringid, rka, &dest_keyring);
1069 /* instantiate the key and link it into a keyring */
1070 ret = key_instantiate_and_link(rka->target_key, payload, plen,
1071 dest_keyring, instkey);
1073 key_put(dest_keyring);
1075 /* discard the assumed authority if it's just been disabled by
1076 * instantiation of the key */
1078 keyctl_change_reqkey_auth(NULL);
1090 * Instantiate a key with the specified payload and link the key into the
1091 * destination keyring if one is given.
1093 * The caller must have the appropriate instantiation permit set for this to
1094 * work (see keyctl_assume_authority). No other permissions are required.
1096 * If successful, 0 will be returned.
1098 long keyctl_instantiate_key(key_serial_t id,
1099 const void __user *_payload,
1101 key_serial_t ringid)
1103 if (_payload && plen) {
1104 struct iovec iov[1] = {
1105 [0].iov_base = (void __user *)_payload,
1109 return keyctl_instantiate_key_common(id, iov, 1, plen, ringid);
1112 return keyctl_instantiate_key_common(id, NULL, 0, 0, ringid);
1116 * Instantiate a key with the specified multipart payload and link the key into
1117 * the destination keyring if one is given.
1119 * The caller must have the appropriate instantiation permit set for this to
1120 * work (see keyctl_assume_authority). No other permissions are required.
1122 * If successful, 0 will be returned.
1124 long keyctl_instantiate_key_iov(key_serial_t id,
1125 const struct iovec __user *_payload_iov,
1127 key_serial_t ringid)
1129 struct iovec iovstack[UIO_FASTIOV], *iov = iovstack;
1132 if (!_payload_iov || !ioc)
1135 ret = rw_copy_check_uvector(WRITE, _payload_iov, ioc,
1136 ARRAY_SIZE(iovstack), iovstack, &iov);
1140 goto no_payload_free;
1142 ret = keyctl_instantiate_key_common(id, iov, ioc, ret, ringid);
1144 if (iov != iovstack)
1149 if (iov != iovstack)
1152 return keyctl_instantiate_key_common(id, NULL, 0, 0, ringid);
1156 * Negatively instantiate the key with the given timeout (in seconds) and link
1157 * the key into the destination keyring if one is given.
1159 * The caller must have the appropriate instantiation permit set for this to
1160 * work (see keyctl_assume_authority). No other permissions are required.
1162 * The key and any links to the key will be automatically garbage collected
1163 * after the timeout expires.
1165 * Negative keys are used to rate limit repeated request_key() calls by causing
1166 * them to return -ENOKEY until the negative key expires.
1168 * If successful, 0 will be returned.
1170 long keyctl_negate_key(key_serial_t id, unsigned timeout, key_serial_t ringid)
1172 return keyctl_reject_key(id, timeout, ENOKEY, ringid);
1176 * Negatively instantiate the key with the given timeout (in seconds) and error
1177 * code and link the key into the destination keyring if one is given.
1179 * The caller must have the appropriate instantiation permit set for this to
1180 * work (see keyctl_assume_authority). No other permissions are required.
1182 * The key and any links to the key will be automatically garbage collected
1183 * after the timeout expires.
1185 * Negative keys are used to rate limit repeated request_key() calls by causing
1186 * them to return the specified error code until the negative key expires.
1188 * If successful, 0 will be returned.
1190 long keyctl_reject_key(key_serial_t id, unsigned timeout, unsigned error,
1191 key_serial_t ringid)
1193 const struct cred *cred = current_cred();
1194 struct request_key_auth *rka;
1195 struct key *instkey, *dest_keyring;
1198 kenter("%d,%u,%u,%d", id, timeout, error, ringid);
1200 /* must be a valid error code and mustn't be a kernel special */
1202 error >= MAX_ERRNO ||
1203 error == ERESTARTSYS ||
1204 error == ERESTARTNOINTR ||
1205 error == ERESTARTNOHAND ||
1206 error == ERESTART_RESTARTBLOCK)
1209 /* the appropriate instantiation authorisation key must have been
1210 * assumed before calling this */
1212 instkey = cred->request_key_auth;
1216 rka = instkey->payload.data;
1217 if (rka->target_key->serial != id)
1220 /* find the destination keyring if present (which must also be
1222 ret = get_instantiation_keyring(ringid, rka, &dest_keyring);
1226 /* instantiate the key and link it into a keyring */
1227 ret = key_reject_and_link(rka->target_key, timeout, error,
1228 dest_keyring, instkey);
1230 key_put(dest_keyring);
1232 /* discard the assumed authority if it's just been disabled by
1233 * instantiation of the key */
1235 keyctl_change_reqkey_auth(NULL);
1242 * Read or set the default keyring in which request_key() will cache keys and
1243 * return the old setting.
1245 * If a process keyring is specified then this will be created if it doesn't
1246 * yet exist. The old setting will be returned if successful.
1248 long keyctl_set_reqkey_keyring(int reqkey_defl)
1251 int ret, old_setting;
1253 old_setting = current_cred_xxx(jit_keyring);
1255 if (reqkey_defl == KEY_REQKEY_DEFL_NO_CHANGE)
1258 new = prepare_creds();
1262 switch (reqkey_defl) {
1263 case KEY_REQKEY_DEFL_THREAD_KEYRING:
1264 ret = install_thread_keyring_to_cred(new);
1269 case KEY_REQKEY_DEFL_PROCESS_KEYRING:
1270 ret = install_process_keyring_to_cred(new);
1278 case KEY_REQKEY_DEFL_DEFAULT:
1279 case KEY_REQKEY_DEFL_SESSION_KEYRING:
1280 case KEY_REQKEY_DEFL_USER_KEYRING:
1281 case KEY_REQKEY_DEFL_USER_SESSION_KEYRING:
1282 case KEY_REQKEY_DEFL_REQUESTOR_KEYRING:
1285 case KEY_REQKEY_DEFL_NO_CHANGE:
1286 case KEY_REQKEY_DEFL_GROUP_KEYRING:
1293 new->jit_keyring = reqkey_defl;
1302 * Set or clear the timeout on a key.
1304 * Either the key must grant the caller Setattr permission or else the caller
1305 * must hold an instantiation authorisation token for the key.
1307 * The timeout is either 0 to clear the timeout, or a number of seconds from
1308 * the current time. The key and any links to the key will be automatically
1309 * garbage collected after the timeout expires.
1311 * If successful, 0 is returned.
1313 long keyctl_set_timeout(key_serial_t id, unsigned timeout)
1315 struct key *key, *instkey;
1319 key_ref = lookup_user_key(id, KEY_LOOKUP_CREATE | KEY_LOOKUP_PARTIAL,
1321 if (IS_ERR(key_ref)) {
1322 /* setting the timeout on a key under construction is permitted
1323 * if we have the authorisation token handy */
1324 if (PTR_ERR(key_ref) == -EACCES) {
1325 instkey = key_get_instantiation_authkey(id);
1326 if (!IS_ERR(instkey)) {
1328 key_ref = lookup_user_key(id,
1331 if (!IS_ERR(key_ref))
1336 ret = PTR_ERR(key_ref);
1341 key = key_ref_to_ptr(key_ref);
1342 key_set_timeout(key, timeout);
1351 * Assume (or clear) the authority to instantiate the specified key.
1353 * This sets the authoritative token currently in force for key instantiation.
1354 * This must be done for a key to be instantiated. It has the effect of making
1355 * available all the keys from the caller of the request_key() that created a
1356 * key to request_key() calls made by the caller of this function.
1358 * The caller must have the instantiation key in their process keyrings with a
1359 * Search permission grant available to the caller.
1361 * If the ID given is 0, then the setting will be cleared and 0 returned.
1363 * If the ID given has a matching an authorisation key, then that key will be
1364 * set and its ID will be returned. The authorisation key can be read to get
1365 * the callout information passed to request_key().
1367 long keyctl_assume_authority(key_serial_t id)
1369 struct key *authkey;
1372 /* special key IDs aren't permitted */
1377 /* we divest ourselves of authority if given an ID of 0 */
1379 ret = keyctl_change_reqkey_auth(NULL);
1383 /* attempt to assume the authority temporarily granted to us whilst we
1384 * instantiate the specified key
1385 * - the authorisation key must be in the current task's keyrings
1388 authkey = key_get_instantiation_authkey(id);
1389 if (IS_ERR(authkey)) {
1390 ret = PTR_ERR(authkey);
1394 ret = keyctl_change_reqkey_auth(authkey);
1399 ret = authkey->serial;
1405 * Get a key's the LSM security label.
1407 * The key must grant the caller View permission for this to work.
1409 * If there's a buffer, then up to buflen bytes of data will be placed into it.
1411 * If successful, the amount of information available will be returned,
1412 * irrespective of how much was copied (including the terminal NUL).
1414 long keyctl_get_security(key_serial_t keyid,
1415 char __user *buffer,
1418 struct key *key, *instkey;
1423 key_ref = lookup_user_key(keyid, KEY_LOOKUP_PARTIAL, KEY_NEED_VIEW);
1424 if (IS_ERR(key_ref)) {
1425 if (PTR_ERR(key_ref) != -EACCES)
1426 return PTR_ERR(key_ref);
1428 /* viewing a key under construction is also permitted if we
1429 * have the authorisation token handy */
1430 instkey = key_get_instantiation_authkey(keyid);
1431 if (IS_ERR(instkey))
1432 return PTR_ERR(instkey);
1435 key_ref = lookup_user_key(keyid, KEY_LOOKUP_PARTIAL, 0);
1436 if (IS_ERR(key_ref))
1437 return PTR_ERR(key_ref);
1440 key = key_ref_to_ptr(key_ref);
1441 ret = security_key_getsecurity(key, &context);
1443 /* if no information was returned, give userspace an empty
1446 if (buffer && buflen > 0 &&
1447 copy_to_user(buffer, "", 1) != 0)
1449 } else if (ret > 0) {
1450 /* return as much data as there's room for */
1451 if (buffer && buflen > 0) {
1455 if (copy_to_user(buffer, context, buflen) != 0)
1462 key_ref_put(key_ref);
1467 * Attempt to install the calling process's session keyring on the process's
1470 * The keyring must exist and must grant the caller LINK permission, and the
1471 * parent process must be single-threaded and must have the same effective
1472 * ownership as this process and mustn't be SUID/SGID.
1474 * The keyring will be emplaced on the parent when it next resumes userspace.
1476 * If successful, 0 will be returned.
1478 long keyctl_session_to_parent(void)
1480 struct task_struct *me, *parent;
1481 const struct cred *mycred, *pcred;
1482 struct callback_head *newwork, *oldwork;
1483 key_ref_t keyring_r;
1487 keyring_r = lookup_user_key(KEY_SPEC_SESSION_KEYRING, 0, KEY_NEED_LINK);
1488 if (IS_ERR(keyring_r))
1489 return PTR_ERR(keyring_r);
1493 /* our parent is going to need a new cred struct, a new tgcred struct
1494 * and new security data, so we allocate them here to prevent ENOMEM in
1496 cred = cred_alloc_blank();
1499 newwork = &cred->rcu;
1501 cred->session_keyring = key_ref_to_ptr(keyring_r);
1503 init_task_work(newwork, key_change_session_keyring);
1507 write_lock_irq(&tasklist_lock);
1511 parent = me->real_parent;
1513 /* the parent mustn't be init and mustn't be a kernel thread */
1514 if (parent->pid <= 1 || !parent->mm)
1517 /* the parent must be single threaded */
1518 if (!thread_group_empty(parent))
1521 /* the parent and the child must have different session keyrings or
1522 * there's no point */
1523 mycred = current_cred();
1524 pcred = __task_cred(parent);
1525 if (mycred == pcred ||
1526 mycred->session_keyring == pcred->session_keyring) {
1531 /* the parent must have the same effective ownership and mustn't be
1533 if (!uid_eq(pcred->uid, mycred->euid) ||
1534 !uid_eq(pcred->euid, mycred->euid) ||
1535 !uid_eq(pcred->suid, mycred->euid) ||
1536 !gid_eq(pcred->gid, mycred->egid) ||
1537 !gid_eq(pcred->egid, mycred->egid) ||
1538 !gid_eq(pcred->sgid, mycred->egid))
1541 /* the keyrings must have the same UID */
1542 if ((pcred->session_keyring &&
1543 !uid_eq(pcred->session_keyring->uid, mycred->euid)) ||
1544 !uid_eq(mycred->session_keyring->uid, mycred->euid))
1547 /* cancel an already pending keyring replacement */
1548 oldwork = task_work_cancel(parent, key_change_session_keyring);
1550 /* the replacement session keyring is applied just prior to userspace
1552 ret = task_work_add(parent, newwork, true);
1556 write_unlock_irq(&tasklist_lock);
1559 put_cred(container_of(oldwork, struct cred, rcu));
1565 key_ref_put(keyring_r);
1570 * The key control system call
1572 SYSCALL_DEFINE5(keyctl, int, option, unsigned long, arg2, unsigned long, arg3,
1573 unsigned long, arg4, unsigned long, arg5)
1576 case KEYCTL_GET_KEYRING_ID:
1577 return keyctl_get_keyring_ID((key_serial_t) arg2,
1580 case KEYCTL_JOIN_SESSION_KEYRING:
1581 return keyctl_join_session_keyring((const char __user *) arg2);
1584 return keyctl_update_key((key_serial_t) arg2,
1585 (const void __user *) arg3,
1589 return keyctl_revoke_key((key_serial_t) arg2);
1591 case KEYCTL_DESCRIBE:
1592 return keyctl_describe_key((key_serial_t) arg2,
1593 (char __user *) arg3,
1597 return keyctl_keyring_clear((key_serial_t) arg2);
1600 return keyctl_keyring_link((key_serial_t) arg2,
1601 (key_serial_t) arg3);
1604 return keyctl_keyring_unlink((key_serial_t) arg2,
1605 (key_serial_t) arg3);
1608 return keyctl_keyring_search((key_serial_t) arg2,
1609 (const char __user *) arg3,
1610 (const char __user *) arg4,
1611 (key_serial_t) arg5);
1614 return keyctl_read_key((key_serial_t) arg2,
1615 (char __user *) arg3,
1619 return keyctl_chown_key((key_serial_t) arg2,
1623 case KEYCTL_SETPERM:
1624 return keyctl_setperm_key((key_serial_t) arg2,
1627 case KEYCTL_INSTANTIATE:
1628 return keyctl_instantiate_key((key_serial_t) arg2,
1629 (const void __user *) arg3,
1631 (key_serial_t) arg5);
1634 return keyctl_negate_key((key_serial_t) arg2,
1636 (key_serial_t) arg4);
1638 case KEYCTL_SET_REQKEY_KEYRING:
1639 return keyctl_set_reqkey_keyring(arg2);
1641 case KEYCTL_SET_TIMEOUT:
1642 return keyctl_set_timeout((key_serial_t) arg2,
1645 case KEYCTL_ASSUME_AUTHORITY:
1646 return keyctl_assume_authority((key_serial_t) arg2);
1648 case KEYCTL_GET_SECURITY:
1649 return keyctl_get_security((key_serial_t) arg2,
1650 (char __user *) arg3,
1653 case KEYCTL_SESSION_TO_PARENT:
1654 return keyctl_session_to_parent();
1657 return keyctl_reject_key((key_serial_t) arg2,
1660 (key_serial_t) arg5);
1662 case KEYCTL_INSTANTIATE_IOV:
1663 return keyctl_instantiate_key_iov(
1664 (key_serial_t) arg2,
1665 (const struct iovec __user *) arg3,
1667 (key_serial_t) arg5);
1669 case KEYCTL_INVALIDATE:
1670 return keyctl_invalidate_key((key_serial_t) arg2);
1672 case KEYCTL_GET_PERSISTENT:
1673 return keyctl_get_persistent((uid_t)arg2, (key_serial_t)arg3);