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/keyctl.h>
19 #include <linux/capability.h>
20 #include <linux/string.h>
21 #include <linux/err.h>
22 #include <linux/vmalloc.h>
23 #include <linux/security.h>
24 #include <asm/uaccess.h>
27 static int key_get_type_from_user(char *type,
28 const char __user *_type,
33 ret = strncpy_from_user(type, _type, len);
36 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 * The keyring must be writable so that we can attach the key to it.
50 * If successful, the new key's serial number is returned, otherwise an error
53 SYSCALL_DEFINE5(add_key, const char __user *, _type,
54 const char __user *, _description,
55 const void __user *, _payload,
59 key_ref_t keyring_ref, key_ref;
60 char type[32], *description;
66 if (plen > 1024 * 1024 - 1)
69 /* draw all the data into kernel space */
70 ret = key_get_type_from_user(type, _type, sizeof(type));
74 description = strndup_user(_description, PAGE_SIZE);
75 if (IS_ERR(description)) {
76 ret = PTR_ERR(description);
80 /* pull the payload in if one was supplied */
86 payload = kmalloc(plen, GFP_KERNEL);
88 if (plen <= PAGE_SIZE)
91 payload = vmalloc(plen);
97 if (copy_from_user(payload, _payload, plen) != 0)
101 /* find the target keyring (which must be writable) */
102 keyring_ref = lookup_user_key(ringid, KEY_LOOKUP_CREATE, KEY_WRITE);
103 if (IS_ERR(keyring_ref)) {
104 ret = PTR_ERR(keyring_ref);
108 /* create or update the requested key and add it to the target
110 key_ref = key_create_or_update(keyring_ref, type, description,
111 payload, plen, KEY_PERM_UNDEF,
113 if (!IS_ERR(key_ref)) {
114 ret = key_ref_to_ptr(key_ref)->serial;
115 key_ref_put(key_ref);
118 ret = PTR_ERR(key_ref);
121 key_ref_put(keyring_ref);
134 * Search the process keyrings and keyring trees linked from those for a
135 * matching key. Keyrings must have appropriate Search permission to be
138 * If a key is found, it will be attached to the destination keyring if there's
139 * one specified and the serial number of the key will be returned.
141 * If no key is found, /sbin/request-key will be invoked if _callout_info is
142 * non-NULL in an attempt to create a key. The _callout_info string will be
143 * passed to /sbin/request-key to aid with completing the request. If the
144 * _callout_info string is "" then it will be changed to "-".
146 SYSCALL_DEFINE4(request_key, const char __user *, _type,
147 const char __user *, _description,
148 const char __user *, _callout_info,
149 key_serial_t, destringid)
151 struct key_type *ktype;
155 char type[32], *description, *callout_info;
158 /* pull the type into kernel space */
159 ret = key_get_type_from_user(type, _type, sizeof(type));
163 /* pull the description into kernel space */
164 description = strndup_user(_description, PAGE_SIZE);
165 if (IS_ERR(description)) {
166 ret = PTR_ERR(description);
170 /* pull the callout info into kernel space */
174 callout_info = strndup_user(_callout_info, PAGE_SIZE);
175 if (IS_ERR(callout_info)) {
176 ret = PTR_ERR(callout_info);
179 callout_len = strlen(callout_info);
182 /* get the destination keyring if specified */
185 dest_ref = lookup_user_key(destringid, KEY_LOOKUP_CREATE,
187 if (IS_ERR(dest_ref)) {
188 ret = PTR_ERR(dest_ref);
193 /* find the key type */
194 ktype = key_type_lookup(type);
196 ret = PTR_ERR(ktype);
201 key = request_key_and_link(ktype, description, callout_info,
202 callout_len, NULL, key_ref_to_ptr(dest_ref),
215 key_ref_put(dest_ref);
225 * Get the ID of the specified process keyring.
227 * The requested keyring must have search permission to be found.
229 * If successful, the ID of the requested keyring will be returned.
231 long keyctl_get_keyring_ID(key_serial_t id, int create)
234 unsigned long lflags;
237 lflags = create ? KEY_LOOKUP_CREATE : 0;
238 key_ref = lookup_user_key(id, lflags, KEY_SEARCH);
239 if (IS_ERR(key_ref)) {
240 ret = PTR_ERR(key_ref);
244 ret = key_ref_to_ptr(key_ref)->serial;
245 key_ref_put(key_ref);
251 * Join a (named) session keyring.
253 * Create and join an anonymous session keyring or join a named session
254 * keyring, creating it if necessary. A named session keyring must have Search
255 * permission for it to be joined. Session keyrings without this permit will
258 * If successful, the ID of the joined session keyring will be returned.
260 long keyctl_join_session_keyring(const char __user *_name)
265 /* fetch the name from userspace */
268 name = strndup_user(_name, PAGE_SIZE);
275 /* join the session */
276 ret = join_session_keyring(name);
284 * Update a key's data payload from the given data.
286 * The key must grant the caller Write permission and the key type must support
287 * updating for this to work. A negative key can be positively instantiated
290 * If successful, 0 will be returned. If the key type does not support
291 * updating, then -EOPNOTSUPP will be returned.
293 long keyctl_update_key(key_serial_t id,
294 const void __user *_payload,
302 if (plen > PAGE_SIZE)
305 /* pull the payload in if one was supplied */
309 payload = kmalloc(plen, GFP_KERNEL);
314 if (copy_from_user(payload, _payload, plen) != 0)
318 /* find the target key (which must be writable) */
319 key_ref = lookup_user_key(id, 0, KEY_WRITE);
320 if (IS_ERR(key_ref)) {
321 ret = PTR_ERR(key_ref);
326 ret = key_update(key_ref, payload, plen);
328 key_ref_put(key_ref);
338 * The key must be grant the caller Write or Setattr permission for this to
339 * work. The key type should give up its quota claim when revoked. The key
340 * and any links to the key will be automatically garbage collected after a
341 * certain amount of time (/proc/sys/kernel/keys/gc_delay).
343 * If successful, 0 is returned.
345 long keyctl_revoke_key(key_serial_t id)
350 key_ref = lookup_user_key(id, 0, KEY_WRITE);
351 if (IS_ERR(key_ref)) {
352 ret = PTR_ERR(key_ref);
355 key_ref = lookup_user_key(id, 0, KEY_SETATTR);
356 if (IS_ERR(key_ref)) {
357 ret = PTR_ERR(key_ref);
362 key_revoke(key_ref_to_ptr(key_ref));
365 key_ref_put(key_ref);
371 * Clear the specified keyring, creating an empty process keyring if one of the
372 * special keyring IDs is used.
374 * The keyring must grant the caller Write permission for this to work. If
375 * successful, 0 will be returned.
377 long keyctl_keyring_clear(key_serial_t ringid)
379 key_ref_t keyring_ref;
382 keyring_ref = lookup_user_key(ringid, KEY_LOOKUP_CREATE, KEY_WRITE);
383 if (IS_ERR(keyring_ref)) {
384 ret = PTR_ERR(keyring_ref);
388 ret = keyring_clear(key_ref_to_ptr(keyring_ref));
390 key_ref_put(keyring_ref);
396 * Create a link from a keyring to a key if there's no matching key in the
397 * keyring, otherwise replace the link to the matching key with a link to the
400 * The key must grant the caller Link permission and the the keyring must grant
401 * the caller Write permission. Furthermore, if an additional link is created,
402 * the keyring's quota will be extended.
404 * If successful, 0 will be returned.
406 long keyctl_keyring_link(key_serial_t id, key_serial_t ringid)
408 key_ref_t keyring_ref, key_ref;
411 keyring_ref = lookup_user_key(ringid, KEY_LOOKUP_CREATE, KEY_WRITE);
412 if (IS_ERR(keyring_ref)) {
413 ret = PTR_ERR(keyring_ref);
417 key_ref = lookup_user_key(id, KEY_LOOKUP_CREATE, KEY_LINK);
418 if (IS_ERR(key_ref)) {
419 ret = PTR_ERR(key_ref);
423 ret = key_link(key_ref_to_ptr(keyring_ref), key_ref_to_ptr(key_ref));
425 key_ref_put(key_ref);
427 key_ref_put(keyring_ref);
433 * Unlink a key from a keyring.
435 * The keyring must grant the caller Write permission for this to work; the key
436 * itself need not grant the caller anything. If the last link to a key is
437 * removed then that key will be scheduled for destruction.
439 * If successful, 0 will be returned.
441 long keyctl_keyring_unlink(key_serial_t id, key_serial_t ringid)
443 key_ref_t keyring_ref, key_ref;
446 keyring_ref = lookup_user_key(ringid, 0, KEY_WRITE);
447 if (IS_ERR(keyring_ref)) {
448 ret = PTR_ERR(keyring_ref);
452 key_ref = lookup_user_key(id, KEY_LOOKUP_FOR_UNLINK, 0);
453 if (IS_ERR(key_ref)) {
454 ret = PTR_ERR(key_ref);
458 ret = key_unlink(key_ref_to_ptr(keyring_ref), key_ref_to_ptr(key_ref));
460 key_ref_put(key_ref);
462 key_ref_put(keyring_ref);
468 * Return a description of a key to userspace.
470 * The key must grant the caller View permission for this to work.
472 * If there's a buffer, we place up to buflen bytes of data into it formatted
473 * in the following way:
475 * type;uid;gid;perm;description<NUL>
477 * If successful, we return the amount of description available, irrespective
478 * of how much we may have copied into the buffer.
480 long keyctl_describe_key(key_serial_t keyid,
484 struct key *key, *instkey;
489 key_ref = lookup_user_key(keyid, KEY_LOOKUP_PARTIAL, KEY_VIEW);
490 if (IS_ERR(key_ref)) {
491 /* viewing a key under construction is permitted if we have the
492 * authorisation token handy */
493 if (PTR_ERR(key_ref) == -EACCES) {
494 instkey = key_get_instantiation_authkey(keyid);
495 if (!IS_ERR(instkey)) {
497 key_ref = lookup_user_key(keyid,
500 if (!IS_ERR(key_ref))
505 ret = PTR_ERR(key_ref);
510 /* calculate how much description we're going to return */
512 tmpbuf = kmalloc(PAGE_SIZE, GFP_KERNEL);
516 key = key_ref_to_ptr(key_ref);
518 ret = snprintf(tmpbuf, PAGE_SIZE - 1,
524 key->description ?: "");
526 /* include a NUL char at the end of the data */
527 if (ret > PAGE_SIZE - 1)
532 /* consider returning the data */
533 if (buffer && buflen > 0) {
537 if (copy_to_user(buffer, tmpbuf, buflen) != 0)
543 key_ref_put(key_ref);
549 * Search the specified keyring and any keyrings it links to for a matching
550 * key. Only keyrings that grant the caller Search permission will be searched
551 * (this includes the starting keyring). Only keys with Search permission can
554 * If successful, the found key will be linked to the destination keyring if
555 * supplied and the key has Link permission, and the found key ID will be
558 long keyctl_keyring_search(key_serial_t ringid,
559 const char __user *_type,
560 const char __user *_description,
561 key_serial_t destringid)
563 struct key_type *ktype;
564 key_ref_t keyring_ref, key_ref, dest_ref;
565 char type[32], *description;
568 /* pull the type and description into kernel space */
569 ret = key_get_type_from_user(type, _type, sizeof(type));
573 description = strndup_user(_description, PAGE_SIZE);
574 if (IS_ERR(description)) {
575 ret = PTR_ERR(description);
579 /* get the keyring at which to begin the search */
580 keyring_ref = lookup_user_key(ringid, 0, KEY_SEARCH);
581 if (IS_ERR(keyring_ref)) {
582 ret = PTR_ERR(keyring_ref);
586 /* get the destination keyring if specified */
589 dest_ref = lookup_user_key(destringid, KEY_LOOKUP_CREATE,
591 if (IS_ERR(dest_ref)) {
592 ret = PTR_ERR(dest_ref);
597 /* find the key type */
598 ktype = key_type_lookup(type);
600 ret = PTR_ERR(ktype);
605 key_ref = keyring_search(keyring_ref, ktype, description);
606 if (IS_ERR(key_ref)) {
607 ret = PTR_ERR(key_ref);
609 /* treat lack or presence of a negative key the same */
615 /* link the resulting key to the destination keyring if we can */
617 ret = key_permission(key_ref, KEY_LINK);
621 ret = key_link(key_ref_to_ptr(dest_ref), key_ref_to_ptr(key_ref));
626 ret = key_ref_to_ptr(key_ref)->serial;
629 key_ref_put(key_ref);
633 key_ref_put(dest_ref);
635 key_ref_put(keyring_ref);
643 * Read a key's payload.
645 * The key must either grant the caller Read permission, or it must grant the
646 * caller Search permission when searched for from the process keyrings.
648 * If successful, we place up to buflen bytes of data into the buffer, if one
649 * is provided, and return the amount of data that is available in the key,
650 * irrespective of how much we copied into the buffer.
652 long keyctl_read_key(key_serial_t keyid, char __user *buffer, size_t buflen)
658 /* find the key first */
659 key_ref = lookup_user_key(keyid, 0, 0);
660 if (IS_ERR(key_ref)) {
665 key = key_ref_to_ptr(key_ref);
667 /* see if we can read it directly */
668 ret = key_permission(key_ref, KEY_READ);
674 /* we can't; see if it's searchable from this process's keyrings
675 * - we automatically take account of the fact that it may be
676 * dangling off an instantiation key
678 if (!is_key_possessed(key_ref)) {
683 /* the key is probably readable - now try to read it */
685 ret = key_validate(key);
688 if (key->type->read) {
689 /* read the data with the semaphore held (since we
691 down_read(&key->sem);
692 ret = key->type->read(key, buffer, buflen);
704 * Change the ownership of a key
706 * The key must grant the caller Setattr permission for this to work, though
707 * the key need not be fully instantiated yet. For the UID to be changed, or
708 * for the GID to be changed to a group the caller is not a member of, the
709 * caller must have sysadmin capability. If either uid or gid is -1 then that
710 * attribute is not changed.
712 * If the UID is to be changed, the new user must have sufficient quota to
713 * accept the key. The quota deduction will be removed from the old user to
714 * the new user should the attribute be changed.
716 * If successful, 0 will be returned.
718 long keyctl_chown_key(key_serial_t id, uid_t uid, gid_t gid)
720 struct key_user *newowner, *zapowner = NULL;
726 if (uid == (uid_t) -1 && gid == (gid_t) -1)
729 key_ref = lookup_user_key(id, KEY_LOOKUP_CREATE | KEY_LOOKUP_PARTIAL,
731 if (IS_ERR(key_ref)) {
732 ret = PTR_ERR(key_ref);
736 key = key_ref_to_ptr(key_ref);
738 /* make the changes with the locks held to prevent chown/chown races */
740 down_write(&key->sem);
742 if (!capable(CAP_SYS_ADMIN)) {
743 /* only the sysadmin can chown a key to some other UID */
744 if (uid != (uid_t) -1 && key->uid != uid)
747 /* only the sysadmin can set the key's GID to a group other
748 * than one of those that the current process subscribes to */
749 if (gid != (gid_t) -1 && gid != key->gid && !in_group_p(gid))
754 if (uid != (uid_t) -1 && uid != key->uid) {
756 newowner = key_user_lookup(uid, current_user_ns());
760 /* transfer the quota burden to the new user */
761 if (test_bit(KEY_FLAG_IN_QUOTA, &key->flags)) {
762 unsigned maxkeys = (uid == 0) ?
763 key_quota_root_maxkeys : key_quota_maxkeys;
764 unsigned maxbytes = (uid == 0) ?
765 key_quota_root_maxbytes : key_quota_maxbytes;
767 spin_lock(&newowner->lock);
768 if (newowner->qnkeys + 1 >= maxkeys ||
769 newowner->qnbytes + key->quotalen >= maxbytes ||
770 newowner->qnbytes + key->quotalen <
775 newowner->qnbytes += key->quotalen;
776 spin_unlock(&newowner->lock);
778 spin_lock(&key->user->lock);
780 key->user->qnbytes -= key->quotalen;
781 spin_unlock(&key->user->lock);
784 atomic_dec(&key->user->nkeys);
785 atomic_inc(&newowner->nkeys);
787 if (test_bit(KEY_FLAG_INSTANTIATED, &key->flags)) {
788 atomic_dec(&key->user->nikeys);
789 atomic_inc(&newowner->nikeys);
792 zapowner = key->user;
793 key->user = newowner;
798 if (gid != (gid_t) -1)
807 key_user_put(zapowner);
812 spin_unlock(&newowner->lock);
819 * Change the permission mask on a key.
821 * The key must grant the caller Setattr permission for this to work, though
822 * the key need not be fully instantiated yet. If the caller does not have
823 * sysadmin capability, it may only change the permission on keys that it owns.
825 long keyctl_setperm_key(key_serial_t id, key_perm_t perm)
832 if (perm & ~(KEY_POS_ALL | KEY_USR_ALL | KEY_GRP_ALL | KEY_OTH_ALL))
835 key_ref = lookup_user_key(id, KEY_LOOKUP_CREATE | KEY_LOOKUP_PARTIAL,
837 if (IS_ERR(key_ref)) {
838 ret = PTR_ERR(key_ref);
842 key = key_ref_to_ptr(key_ref);
844 /* make the changes with the locks held to prevent chown/chmod races */
846 down_write(&key->sem);
848 /* if we're not the sysadmin, we can only change a key that we own */
849 if (capable(CAP_SYS_ADMIN) || key->uid == current_fsuid()) {
861 * Get the destination keyring for instantiation and check that the caller has
862 * Write permission on it.
864 static long get_instantiation_keyring(key_serial_t ringid,
865 struct request_key_auth *rka,
866 struct key **_dest_keyring)
870 *_dest_keyring = NULL;
872 /* just return a NULL pointer if we weren't asked to make a link */
876 /* if a specific keyring is nominated by ID, then use that */
878 dkref = lookup_user_key(ringid, KEY_LOOKUP_CREATE, KEY_WRITE);
880 return PTR_ERR(dkref);
881 *_dest_keyring = key_ref_to_ptr(dkref);
885 if (ringid == KEY_SPEC_REQKEY_AUTH_KEY)
888 /* otherwise specify the destination keyring recorded in the
889 * authorisation key (any KEY_SPEC_*_KEYRING) */
890 if (ringid >= KEY_SPEC_REQUESTOR_KEYRING) {
891 *_dest_keyring = key_get(rka->dest_keyring);
899 * Change the request_key authorisation key on the current process.
901 static int keyctl_change_reqkey_auth(struct key *key)
905 new = prepare_creds();
909 key_put(new->request_key_auth);
910 new->request_key_auth = key_get(key);
912 return commit_creds(new);
916 * Instantiate a key with the specified payload and link the key into the
917 * destination keyring if one is given.
919 * The caller must have the appropriate instantiation permit set for this to
920 * work (see keyctl_assume_authority). No other permissions are required.
922 * If successful, 0 will be returned.
924 long keyctl_instantiate_key(key_serial_t id,
925 const void __user *_payload,
929 const struct cred *cred = current_cred();
930 struct request_key_auth *rka;
931 struct key *instkey, *dest_keyring;
936 kenter("%d,,%zu,%d", id, plen, ringid);
939 if (plen > 1024 * 1024 - 1)
942 /* the appropriate instantiation authorisation key must have been
943 * assumed before calling this */
945 instkey = cred->request_key_auth;
949 rka = instkey->payload.data;
950 if (rka->target_key->serial != id)
953 /* pull the payload in if one was supplied */
958 payload = kmalloc(plen, GFP_KERNEL);
960 if (plen <= PAGE_SIZE)
963 payload = vmalloc(plen);
969 if (copy_from_user(payload, _payload, plen) != 0)
973 /* find the destination keyring amongst those belonging to the
975 ret = get_instantiation_keyring(ringid, rka, &dest_keyring);
979 /* instantiate the key and link it into a keyring */
980 ret = key_instantiate_and_link(rka->target_key, payload, plen,
981 dest_keyring, instkey);
983 key_put(dest_keyring);
985 /* discard the assumed authority if it's just been disabled by
986 * instantiation of the key */
988 keyctl_change_reqkey_auth(NULL);
1000 * Negatively instantiate the key with the given timeout (in seconds) and link
1001 * the key into the destination keyring if one is given.
1003 * The caller must have the appropriate instantiation permit set for this to
1004 * work (see keyctl_assume_authority). No other permissions are required.
1006 * The key and any links to the key will be automatically garbage collected
1007 * after the timeout expires.
1009 * Negative keys are used to rate limit repeated request_key() calls by causing
1010 * them to return -ENOKEY until the negative key expires.
1012 * If successful, 0 will be returned.
1014 long keyctl_negate_key(key_serial_t id, unsigned timeout, key_serial_t ringid)
1016 const struct cred *cred = current_cred();
1017 struct request_key_auth *rka;
1018 struct key *instkey, *dest_keyring;
1021 kenter("%d,%u,%d", id, timeout, ringid);
1023 /* the appropriate instantiation authorisation key must have been
1024 * assumed before calling this */
1026 instkey = cred->request_key_auth;
1030 rka = instkey->payload.data;
1031 if (rka->target_key->serial != id)
1034 /* find the destination keyring if present (which must also be
1036 ret = get_instantiation_keyring(ringid, rka, &dest_keyring);
1040 /* instantiate the key and link it into a keyring */
1041 ret = key_negate_and_link(rka->target_key, timeout,
1042 dest_keyring, instkey);
1044 key_put(dest_keyring);
1046 /* discard the assumed authority if it's just been disabled by
1047 * instantiation of the key */
1049 keyctl_change_reqkey_auth(NULL);
1056 * Read or set the default keyring in which request_key() will cache keys and
1057 * return the old setting.
1059 * If a process keyring is specified then this will be created if it doesn't
1060 * yet exist. The old setting will be returned if successful.
1062 long keyctl_set_reqkey_keyring(int reqkey_defl)
1065 int ret, old_setting;
1067 old_setting = current_cred_xxx(jit_keyring);
1069 if (reqkey_defl == KEY_REQKEY_DEFL_NO_CHANGE)
1072 new = prepare_creds();
1076 switch (reqkey_defl) {
1077 case KEY_REQKEY_DEFL_THREAD_KEYRING:
1078 ret = install_thread_keyring_to_cred(new);
1083 case KEY_REQKEY_DEFL_PROCESS_KEYRING:
1084 ret = install_process_keyring_to_cred(new);
1092 case KEY_REQKEY_DEFL_DEFAULT:
1093 case KEY_REQKEY_DEFL_SESSION_KEYRING:
1094 case KEY_REQKEY_DEFL_USER_KEYRING:
1095 case KEY_REQKEY_DEFL_USER_SESSION_KEYRING:
1096 case KEY_REQKEY_DEFL_REQUESTOR_KEYRING:
1099 case KEY_REQKEY_DEFL_NO_CHANGE:
1100 case KEY_REQKEY_DEFL_GROUP_KEYRING:
1107 new->jit_keyring = reqkey_defl;
1116 * Set or clear the timeout on a key.
1118 * Either the key must grant the caller Setattr permission or else the caller
1119 * must hold an instantiation authorisation token for the key.
1121 * The timeout is either 0 to clear the timeout, or a number of seconds from
1122 * the current time. The key and any links to the key will be automatically
1123 * garbage collected after the timeout expires.
1125 * If successful, 0 is returned.
1127 long keyctl_set_timeout(key_serial_t id, unsigned timeout)
1129 struct timespec now;
1130 struct key *key, *instkey;
1135 key_ref = lookup_user_key(id, KEY_LOOKUP_CREATE | KEY_LOOKUP_PARTIAL,
1137 if (IS_ERR(key_ref)) {
1138 /* setting the timeout on a key under construction is permitted
1139 * if we have the authorisation token handy */
1140 if (PTR_ERR(key_ref) == -EACCES) {
1141 instkey = key_get_instantiation_authkey(id);
1142 if (!IS_ERR(instkey)) {
1144 key_ref = lookup_user_key(id,
1147 if (!IS_ERR(key_ref))
1152 ret = PTR_ERR(key_ref);
1157 key = key_ref_to_ptr(key_ref);
1159 /* make the changes with the locks held to prevent races */
1160 down_write(&key->sem);
1164 now = current_kernel_time();
1165 expiry = now.tv_sec + timeout;
1168 key->expiry = expiry;
1169 key_schedule_gc(key->expiry + key_gc_delay);
1171 up_write(&key->sem);
1180 * Assume (or clear) the authority to instantiate the specified key.
1182 * This sets the authoritative token currently in force for key instantiation.
1183 * This must be done for a key to be instantiated. It has the effect of making
1184 * available all the keys from the caller of the request_key() that created a
1185 * key to request_key() calls made by the caller of this function.
1187 * The caller must have the instantiation key in their process keyrings with a
1188 * Search permission grant available to the caller.
1190 * If the ID given is 0, then the setting will be cleared and 0 returned.
1192 * If the ID given has a matching an authorisation key, then that key will be
1193 * set and its ID will be returned. The authorisation key can be read to get
1194 * the callout information passed to request_key().
1196 long keyctl_assume_authority(key_serial_t id)
1198 struct key *authkey;
1201 /* special key IDs aren't permitted */
1206 /* we divest ourselves of authority if given an ID of 0 */
1208 ret = keyctl_change_reqkey_auth(NULL);
1212 /* attempt to assume the authority temporarily granted to us whilst we
1213 * instantiate the specified key
1214 * - the authorisation key must be in the current task's keyrings
1217 authkey = key_get_instantiation_authkey(id);
1218 if (IS_ERR(authkey)) {
1219 ret = PTR_ERR(authkey);
1223 ret = keyctl_change_reqkey_auth(authkey);
1228 ret = authkey->serial;
1234 * Get a key's the LSM security label.
1236 * The key must grant the caller View permission for this to work.
1238 * If there's a buffer, then up to buflen bytes of data will be placed into it.
1240 * If successful, the amount of information available will be returned,
1241 * irrespective of how much was copied (including the terminal NUL).
1243 long keyctl_get_security(key_serial_t keyid,
1244 char __user *buffer,
1247 struct key *key, *instkey;
1252 key_ref = lookup_user_key(keyid, KEY_LOOKUP_PARTIAL, KEY_VIEW);
1253 if (IS_ERR(key_ref)) {
1254 if (PTR_ERR(key_ref) != -EACCES)
1255 return PTR_ERR(key_ref);
1257 /* viewing a key under construction is also permitted if we
1258 * have the authorisation token handy */
1259 instkey = key_get_instantiation_authkey(keyid);
1260 if (IS_ERR(instkey))
1261 return PTR_ERR(instkey);
1264 key_ref = lookup_user_key(keyid, KEY_LOOKUP_PARTIAL, 0);
1265 if (IS_ERR(key_ref))
1266 return PTR_ERR(key_ref);
1269 key = key_ref_to_ptr(key_ref);
1270 ret = security_key_getsecurity(key, &context);
1272 /* if no information was returned, give userspace an empty
1275 if (buffer && buflen > 0 &&
1276 copy_to_user(buffer, "", 1) != 0)
1278 } else if (ret > 0) {
1279 /* return as much data as there's room for */
1280 if (buffer && buflen > 0) {
1284 if (copy_to_user(buffer, context, buflen) != 0)
1291 key_ref_put(key_ref);
1296 * Attempt to install the calling process's session keyring on the process's
1299 * The keyring must exist and must grant the caller LINK permission, and the
1300 * parent process must be single-threaded and must have the same effective
1301 * ownership as this process and mustn't be SUID/SGID.
1303 * The keyring will be emplaced on the parent when it next resumes userspace.
1305 * If successful, 0 will be returned.
1307 long keyctl_session_to_parent(void)
1309 #ifdef TIF_NOTIFY_RESUME
1310 struct task_struct *me, *parent;
1311 const struct cred *mycred, *pcred;
1312 struct cred *cred, *oldcred;
1313 key_ref_t keyring_r;
1316 keyring_r = lookup_user_key(KEY_SPEC_SESSION_KEYRING, 0, KEY_LINK);
1317 if (IS_ERR(keyring_r))
1318 return PTR_ERR(keyring_r);
1320 /* our parent is going to need a new cred struct, a new tgcred struct
1321 * and new security data, so we allocate them here to prevent ENOMEM in
1324 cred = cred_alloc_blank();
1328 cred->tgcred->session_keyring = key_ref_to_ptr(keyring_r);
1333 write_lock_irq(&tasklist_lock);
1335 parent = me->real_parent;
1338 /* the parent mustn't be init and mustn't be a kernel thread */
1339 if (parent->pid <= 1 || !parent->mm)
1342 /* the parent must be single threaded */
1343 if (!thread_group_empty(parent))
1346 /* the parent and the child must have different session keyrings or
1347 * there's no point */
1348 mycred = current_cred();
1349 pcred = __task_cred(parent);
1350 if (mycred == pcred ||
1351 mycred->tgcred->session_keyring == pcred->tgcred->session_keyring)
1354 /* the parent must have the same effective ownership and mustn't be
1356 if (pcred->uid != mycred->euid ||
1357 pcred->euid != mycred->euid ||
1358 pcred->suid != mycred->euid ||
1359 pcred->gid != mycred->egid ||
1360 pcred->egid != mycred->egid ||
1361 pcred->sgid != mycred->egid)
1364 /* the keyrings must have the same UID */
1365 if ((pcred->tgcred->session_keyring &&
1366 pcred->tgcred->session_keyring->uid != mycred->euid) ||
1367 mycred->tgcred->session_keyring->uid != mycred->euid)
1370 /* if there's an already pending keyring replacement, then we replace
1372 oldcred = parent->replacement_session_keyring;
1374 /* the replacement session keyring is applied just prior to userspace
1376 parent->replacement_session_keyring = cred;
1378 set_ti_thread_flag(task_thread_info(parent), TIF_NOTIFY_RESUME);
1380 write_unlock_irq(&tasklist_lock);
1389 write_unlock_irq(&tasklist_lock);
1395 key_ref_put(keyring_r);
1398 #else /* !TIF_NOTIFY_RESUME */
1400 * To be removed when TIF_NOTIFY_RESUME has been implemented on
1403 #warning TIF_NOTIFY_RESUME not implemented
1405 #endif /* !TIF_NOTIFY_RESUME */
1409 * The key control system call
1411 SYSCALL_DEFINE5(keyctl, int, option, unsigned long, arg2, unsigned long, arg3,
1412 unsigned long, arg4, unsigned long, arg5)
1415 case KEYCTL_GET_KEYRING_ID:
1416 return keyctl_get_keyring_ID((key_serial_t) arg2,
1419 case KEYCTL_JOIN_SESSION_KEYRING:
1420 return keyctl_join_session_keyring((const char __user *) arg2);
1423 return keyctl_update_key((key_serial_t) arg2,
1424 (const void __user *) arg3,
1428 return keyctl_revoke_key((key_serial_t) arg2);
1430 case KEYCTL_DESCRIBE:
1431 return keyctl_describe_key((key_serial_t) arg2,
1432 (char __user *) arg3,
1436 return keyctl_keyring_clear((key_serial_t) arg2);
1439 return keyctl_keyring_link((key_serial_t) arg2,
1440 (key_serial_t) arg3);
1443 return keyctl_keyring_unlink((key_serial_t) arg2,
1444 (key_serial_t) arg3);
1447 return keyctl_keyring_search((key_serial_t) arg2,
1448 (const char __user *) arg3,
1449 (const char __user *) arg4,
1450 (key_serial_t) arg5);
1453 return keyctl_read_key((key_serial_t) arg2,
1454 (char __user *) arg3,
1458 return keyctl_chown_key((key_serial_t) arg2,
1462 case KEYCTL_SETPERM:
1463 return keyctl_setperm_key((key_serial_t) arg2,
1466 case KEYCTL_INSTANTIATE:
1467 return keyctl_instantiate_key((key_serial_t) arg2,
1468 (const void __user *) arg3,
1470 (key_serial_t) arg5);
1473 return keyctl_negate_key((key_serial_t) arg2,
1475 (key_serial_t) arg4);
1477 case KEYCTL_SET_REQKEY_KEYRING:
1478 return keyctl_set_reqkey_keyring(arg2);
1480 case KEYCTL_SET_TIMEOUT:
1481 return keyctl_set_timeout((key_serial_t) arg2,
1484 case KEYCTL_ASSUME_AUTHORITY:
1485 return keyctl_assume_authority((key_serial_t) arg2);
1487 case KEYCTL_GET_SECURITY:
1488 return keyctl_get_security((key_serial_t) arg2,
1489 (char __user *) arg3,
1492 case KEYCTL_SESSION_TO_PARENT:
1493 return keyctl_session_to_parent();