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 #define KEY_MAX_DESC_SIZE 4096
31 static int key_get_type_from_user(char *type,
32 const char __user *_type,
37 ret = strncpy_from_user(type, _type, len);
40 if (ret == 0 || ret >= len)
49 * Extract the description of a new key from userspace and either add it as a
50 * new key to the specified keyring or update a matching key in that keyring.
52 * If the description is NULL or an empty string, the key type is asked to
53 * generate one from the payload.
55 * The keyring must be writable so that we can attach the key to it.
57 * If successful, the new key's serial number is returned, otherwise an error
60 SYSCALL_DEFINE5(add_key, const char __user *, _type,
61 const char __user *, _description,
62 const void __user *, _payload,
66 key_ref_t keyring_ref, key_ref;
67 char type[32], *description;
73 if (plen > 1024 * 1024 - 1)
76 /* draw all the data into kernel space */
77 ret = key_get_type_from_user(type, _type, sizeof(type));
83 description = strndup_user(_description, KEY_MAX_DESC_SIZE);
84 if (IS_ERR(description)) {
85 ret = PTR_ERR(description);
91 } else if ((description[0] == '.') &&
92 (strncmp(type, "keyring", 7) == 0)) {
98 /* pull the payload in if one was supplied */
104 payload = kmalloc(plen, GFP_KERNEL | __GFP_NOWARN);
106 if (plen <= PAGE_SIZE)
109 payload = vmalloc(plen);
115 if (copy_from_user(payload, _payload, plen) != 0)
119 /* find the target keyring (which must be writable) */
120 keyring_ref = lookup_user_key(ringid, KEY_LOOKUP_CREATE, KEY_NEED_WRITE);
121 if (IS_ERR(keyring_ref)) {
122 ret = PTR_ERR(keyring_ref);
126 /* create or update the requested key and add it to the target
128 key_ref = key_create_or_update(keyring_ref, type, description,
129 payload, plen, KEY_PERM_UNDEF,
131 if (!IS_ERR(key_ref)) {
132 ret = key_ref_to_ptr(key_ref)->serial;
133 key_ref_put(key_ref);
136 ret = PTR_ERR(key_ref);
139 key_ref_put(keyring_ref);
152 * Search the process keyrings and keyring trees linked from those for a
153 * matching key. Keyrings must have appropriate Search permission to be
156 * If a key is found, it will be attached to the destination keyring if there's
157 * one specified and the serial number of the key will be returned.
159 * If no key is found, /sbin/request-key will be invoked if _callout_info is
160 * non-NULL in an attempt to create a key. The _callout_info string will be
161 * passed to /sbin/request-key to aid with completing the request. If the
162 * _callout_info string is "" then it will be changed to "-".
164 SYSCALL_DEFINE4(request_key, const char __user *, _type,
165 const char __user *, _description,
166 const char __user *, _callout_info,
167 key_serial_t, destringid)
169 struct key_type *ktype;
173 char type[32], *description, *callout_info;
176 /* pull the type into kernel space */
177 ret = key_get_type_from_user(type, _type, sizeof(type));
181 /* pull the description into kernel space */
182 description = strndup_user(_description, KEY_MAX_DESC_SIZE);
183 if (IS_ERR(description)) {
184 ret = PTR_ERR(description);
188 /* pull the callout info into kernel space */
192 callout_info = strndup_user(_callout_info, PAGE_SIZE);
193 if (IS_ERR(callout_info)) {
194 ret = PTR_ERR(callout_info);
197 callout_len = strlen(callout_info);
200 /* get the destination keyring if specified */
203 dest_ref = lookup_user_key(destringid, KEY_LOOKUP_CREATE,
205 if (IS_ERR(dest_ref)) {
206 ret = PTR_ERR(dest_ref);
211 /* find the key type */
212 ktype = key_type_lookup(type);
214 ret = PTR_ERR(ktype);
219 key = request_key_and_link(ktype, description, callout_info,
220 callout_len, NULL, key_ref_to_ptr(dest_ref),
227 /* wait for the key to finish being constructed */
228 ret = wait_for_key_construction(key, 1);
239 key_ref_put(dest_ref);
249 * Get the ID of the specified process keyring.
251 * The requested keyring must have search permission to be found.
253 * If successful, the ID of the requested keyring will be returned.
255 long keyctl_get_keyring_ID(key_serial_t id, int create)
258 unsigned long lflags;
261 lflags = create ? KEY_LOOKUP_CREATE : 0;
262 key_ref = lookup_user_key(id, lflags, KEY_NEED_SEARCH);
263 if (IS_ERR(key_ref)) {
264 ret = PTR_ERR(key_ref);
268 ret = key_ref_to_ptr(key_ref)->serial;
269 key_ref_put(key_ref);
275 * Join a (named) session keyring.
277 * Create and join an anonymous session keyring or join a named session
278 * keyring, creating it if necessary. A named session keyring must have Search
279 * permission for it to be joined. Session keyrings without this permit will
282 * If successful, the ID of the joined session keyring will be returned.
284 long keyctl_join_session_keyring(const char __user *_name)
289 /* fetch the name from userspace */
292 name = strndup_user(_name, KEY_MAX_DESC_SIZE);
299 /* join the session */
300 ret = join_session_keyring(name);
308 * Update a key's data payload from the given data.
310 * The key must grant the caller Write permission and the key type must support
311 * updating for this to work. A negative key can be positively instantiated
314 * If successful, 0 will be returned. If the key type does not support
315 * updating, then -EOPNOTSUPP will be returned.
317 long keyctl_update_key(key_serial_t id,
318 const void __user *_payload,
326 if (plen > PAGE_SIZE)
329 /* pull the payload in if one was supplied */
333 payload = kmalloc(plen, GFP_KERNEL);
338 if (copy_from_user(payload, _payload, plen) != 0)
342 /* find the target key (which must be writable) */
343 key_ref = lookup_user_key(id, 0, KEY_NEED_WRITE);
344 if (IS_ERR(key_ref)) {
345 ret = PTR_ERR(key_ref);
350 ret = key_update(key_ref, payload, plen);
352 key_ref_put(key_ref);
362 * The key must be grant the caller Write or Setattr permission for this to
363 * work. The key type should give up its quota claim when revoked. The key
364 * and any links to the key will be automatically garbage collected after a
365 * certain amount of time (/proc/sys/kernel/keys/gc_delay).
367 * If successful, 0 is returned.
369 long keyctl_revoke_key(key_serial_t id)
374 key_ref = lookup_user_key(id, 0, KEY_NEED_WRITE);
375 if (IS_ERR(key_ref)) {
376 ret = PTR_ERR(key_ref);
379 key_ref = lookup_user_key(id, 0, KEY_NEED_SETATTR);
380 if (IS_ERR(key_ref)) {
381 ret = PTR_ERR(key_ref);
386 key_revoke(key_ref_to_ptr(key_ref));
389 key_ref_put(key_ref);
397 * The key must be grant the caller Invalidate permission for this to work.
398 * The key and any links to the key will be automatically garbage collected
401 * If successful, 0 is returned.
403 long keyctl_invalidate_key(key_serial_t id)
410 key_ref = lookup_user_key(id, 0, KEY_NEED_SEARCH);
411 if (IS_ERR(key_ref)) {
412 ret = PTR_ERR(key_ref);
414 /* Root is permitted to invalidate certain special keys */
415 if (capable(CAP_SYS_ADMIN)) {
416 key_ref = lookup_user_key(id, 0, 0);
419 if (test_bit(KEY_FLAG_ROOT_CAN_INVAL,
420 &key_ref_to_ptr(key_ref)->flags))
429 key_invalidate(key_ref_to_ptr(key_ref));
432 key_ref_put(key_ref);
434 kleave(" = %ld", ret);
439 * Clear the specified keyring, creating an empty process keyring if one of the
440 * special keyring IDs is used.
442 * The keyring must grant the caller Write permission for this to work. If
443 * successful, 0 will be returned.
445 long keyctl_keyring_clear(key_serial_t ringid)
447 key_ref_t keyring_ref;
450 keyring_ref = lookup_user_key(ringid, KEY_LOOKUP_CREATE, KEY_NEED_WRITE);
451 if (IS_ERR(keyring_ref)) {
452 ret = PTR_ERR(keyring_ref);
454 /* Root is permitted to invalidate certain special keyrings */
455 if (capable(CAP_SYS_ADMIN)) {
456 keyring_ref = lookup_user_key(ringid, 0, 0);
457 if (IS_ERR(keyring_ref))
459 if (test_bit(KEY_FLAG_ROOT_CAN_CLEAR,
460 &key_ref_to_ptr(keyring_ref)->flags))
469 ret = keyring_clear(key_ref_to_ptr(keyring_ref));
471 key_ref_put(keyring_ref);
477 * Create a link from a keyring to a key if there's no matching key in the
478 * keyring, otherwise replace the link to the matching key with a link to the
481 * The key must grant the caller Link permission and the the keyring must grant
482 * the caller Write permission. Furthermore, if an additional link is created,
483 * the keyring's quota will be extended.
485 * If successful, 0 will be returned.
487 long keyctl_keyring_link(key_serial_t id, key_serial_t ringid)
489 key_ref_t keyring_ref, key_ref;
492 keyring_ref = lookup_user_key(ringid, KEY_LOOKUP_CREATE, KEY_NEED_WRITE);
493 if (IS_ERR(keyring_ref)) {
494 ret = PTR_ERR(keyring_ref);
498 key_ref = lookup_user_key(id, KEY_LOOKUP_CREATE, KEY_NEED_LINK);
499 if (IS_ERR(key_ref)) {
500 ret = PTR_ERR(key_ref);
504 ret = key_link(key_ref_to_ptr(keyring_ref), key_ref_to_ptr(key_ref));
506 key_ref_put(key_ref);
508 key_ref_put(keyring_ref);
514 * Unlink a key from a keyring.
516 * The keyring must grant the caller Write permission for this to work; the key
517 * itself need not grant the caller anything. If the last link to a key is
518 * removed then that key will be scheduled for destruction.
520 * If successful, 0 will be returned.
522 long keyctl_keyring_unlink(key_serial_t id, key_serial_t ringid)
524 key_ref_t keyring_ref, key_ref;
527 keyring_ref = lookup_user_key(ringid, 0, KEY_NEED_WRITE);
528 if (IS_ERR(keyring_ref)) {
529 ret = PTR_ERR(keyring_ref);
533 key_ref = lookup_user_key(id, KEY_LOOKUP_FOR_UNLINK, 0);
534 if (IS_ERR(key_ref)) {
535 ret = PTR_ERR(key_ref);
539 ret = key_unlink(key_ref_to_ptr(keyring_ref), key_ref_to_ptr(key_ref));
541 key_ref_put(key_ref);
543 key_ref_put(keyring_ref);
549 * Return a description of a key to userspace.
551 * The key must grant the caller View permission for this to work.
553 * If there's a buffer, we place up to buflen bytes of data into it formatted
554 * in the following way:
556 * type;uid;gid;perm;description<NUL>
558 * If successful, we return the amount of description available, irrespective
559 * of how much we may have copied into the buffer.
561 long keyctl_describe_key(key_serial_t keyid,
565 struct key *key, *instkey;
569 int desclen, infolen;
571 key_ref = lookup_user_key(keyid, KEY_LOOKUP_PARTIAL, KEY_NEED_VIEW);
572 if (IS_ERR(key_ref)) {
573 /* viewing a key under construction is permitted if we have the
574 * authorisation token handy */
575 if (PTR_ERR(key_ref) == -EACCES) {
576 instkey = key_get_instantiation_authkey(keyid);
577 if (!IS_ERR(instkey)) {
579 key_ref = lookup_user_key(keyid,
582 if (!IS_ERR(key_ref))
587 ret = PTR_ERR(key_ref);
592 key = key_ref_to_ptr(key_ref);
593 desclen = strlen(key->description);
595 /* calculate how much information we're going to return */
597 infobuf = kasprintf(GFP_KERNEL,
600 from_kuid_munged(current_user_ns(), key->uid),
601 from_kgid_munged(current_user_ns(), key->gid),
605 infolen = strlen(infobuf);
606 ret = infolen + desclen + 1;
608 /* consider returning the data */
609 if (buffer && buflen >= ret) {
610 if (copy_to_user(buffer, infobuf, infolen) != 0 ||
611 copy_to_user(buffer + infolen, key->description,
618 key_ref_put(key_ref);
624 * Search the specified keyring and any keyrings it links to for a matching
625 * key. Only keyrings that grant the caller Search permission will be searched
626 * (this includes the starting keyring). Only keys with Search permission can
629 * If successful, the found key will be linked to the destination keyring if
630 * supplied and the key has Link permission, and the found key ID will be
633 long keyctl_keyring_search(key_serial_t ringid,
634 const char __user *_type,
635 const char __user *_description,
636 key_serial_t destringid)
638 struct key_type *ktype;
639 key_ref_t keyring_ref, key_ref, dest_ref;
640 char type[32], *description;
643 /* pull the type and description into kernel space */
644 ret = key_get_type_from_user(type, _type, sizeof(type));
648 description = strndup_user(_description, KEY_MAX_DESC_SIZE);
649 if (IS_ERR(description)) {
650 ret = PTR_ERR(description);
654 /* get the keyring at which to begin the search */
655 keyring_ref = lookup_user_key(ringid, 0, KEY_NEED_SEARCH);
656 if (IS_ERR(keyring_ref)) {
657 ret = PTR_ERR(keyring_ref);
661 /* get the destination keyring if specified */
664 dest_ref = lookup_user_key(destringid, KEY_LOOKUP_CREATE,
666 if (IS_ERR(dest_ref)) {
667 ret = PTR_ERR(dest_ref);
672 /* find the key type */
673 ktype = key_type_lookup(type);
675 ret = PTR_ERR(ktype);
680 key_ref = keyring_search(keyring_ref, ktype, description);
681 if (IS_ERR(key_ref)) {
682 ret = PTR_ERR(key_ref);
684 /* treat lack or presence of a negative key the same */
690 /* link the resulting key to the destination keyring if we can */
692 ret = key_permission(key_ref, KEY_NEED_LINK);
696 ret = key_link(key_ref_to_ptr(dest_ref), key_ref_to_ptr(key_ref));
701 ret = key_ref_to_ptr(key_ref)->serial;
704 key_ref_put(key_ref);
708 key_ref_put(dest_ref);
710 key_ref_put(keyring_ref);
718 * Read a key's payload.
720 * The key must either grant the caller Read permission, or it must grant the
721 * caller Search permission when searched for from the process keyrings.
723 * If successful, we place up to buflen bytes of data into the buffer, if one
724 * is provided, and return the amount of data that is available in the key,
725 * irrespective of how much we copied into the buffer.
727 long keyctl_read_key(key_serial_t keyid, char __user *buffer, size_t buflen)
733 /* find the key first */
734 key_ref = lookup_user_key(keyid, 0, 0);
735 if (IS_ERR(key_ref)) {
740 key = key_ref_to_ptr(key_ref);
742 /* see if we can read it directly */
743 ret = key_permission(key_ref, KEY_NEED_READ);
749 /* we can't; see if it's searchable from this process's keyrings
750 * - we automatically take account of the fact that it may be
751 * dangling off an instantiation key
753 if (!is_key_possessed(key_ref)) {
758 /* the key is probably readable - now try to read it */
760 ret = key_validate(key);
763 if (key->type->read) {
764 /* read the data with the semaphore held (since we
766 down_read(&key->sem);
767 ret = key->type->read(key, buffer, buflen);
779 * Change the ownership of a key
781 * The key must grant the caller Setattr permission for this to work, though
782 * the key need not be fully instantiated yet. For the UID to be changed, or
783 * for the GID to be changed to a group the caller is not a member of, the
784 * caller must have sysadmin capability. If either uid or gid is -1 then that
785 * attribute is not changed.
787 * If the UID is to be changed, the new user must have sufficient quota to
788 * accept the key. The quota deduction will be removed from the old user to
789 * the new user should the attribute be changed.
791 * If successful, 0 will be returned.
793 long keyctl_chown_key(key_serial_t id, uid_t user, gid_t group)
795 struct key_user *newowner, *zapowner = NULL;
802 uid = make_kuid(current_user_ns(), user);
803 gid = make_kgid(current_user_ns(), group);
805 if ((user != (uid_t) -1) && !uid_valid(uid))
807 if ((group != (gid_t) -1) && !gid_valid(gid))
811 if (user == (uid_t) -1 && group == (gid_t) -1)
814 key_ref = lookup_user_key(id, KEY_LOOKUP_CREATE | KEY_LOOKUP_PARTIAL,
816 if (IS_ERR(key_ref)) {
817 ret = PTR_ERR(key_ref);
821 key = key_ref_to_ptr(key_ref);
823 /* make the changes with the locks held to prevent chown/chown races */
825 down_write(&key->sem);
827 if (!capable(CAP_SYS_ADMIN)) {
828 /* only the sysadmin can chown a key to some other UID */
829 if (user != (uid_t) -1 && !uid_eq(key->uid, uid))
832 /* only the sysadmin can set the key's GID to a group other
833 * than one of those that the current process subscribes to */
834 if (group != (gid_t) -1 && !gid_eq(gid, key->gid) && !in_group_p(gid))
839 if (user != (uid_t) -1 && !uid_eq(uid, key->uid)) {
841 newowner = key_user_lookup(uid);
845 /* transfer the quota burden to the new user */
846 if (test_bit(KEY_FLAG_IN_QUOTA, &key->flags)) {
847 unsigned maxkeys = uid_eq(uid, GLOBAL_ROOT_UID) ?
848 key_quota_root_maxkeys : key_quota_maxkeys;
849 unsigned maxbytes = uid_eq(uid, GLOBAL_ROOT_UID) ?
850 key_quota_root_maxbytes : key_quota_maxbytes;
852 spin_lock(&newowner->lock);
853 if (newowner->qnkeys + 1 >= maxkeys ||
854 newowner->qnbytes + key->quotalen >= maxbytes ||
855 newowner->qnbytes + key->quotalen <
860 newowner->qnbytes += key->quotalen;
861 spin_unlock(&newowner->lock);
863 spin_lock(&key->user->lock);
865 key->user->qnbytes -= key->quotalen;
866 spin_unlock(&key->user->lock);
869 atomic_dec(&key->user->nkeys);
870 atomic_inc(&newowner->nkeys);
872 if (test_bit(KEY_FLAG_INSTANTIATED, &key->flags)) {
873 atomic_dec(&key->user->nikeys);
874 atomic_inc(&newowner->nikeys);
877 zapowner = key->user;
878 key->user = newowner;
883 if (group != (gid_t) -1)
892 key_user_put(zapowner);
897 spin_unlock(&newowner->lock);
904 * Change the permission mask on a key.
906 * The key must grant the caller Setattr permission for this to work, though
907 * the key need not be fully instantiated yet. If the caller does not have
908 * sysadmin capability, it may only change the permission on keys that it owns.
910 long keyctl_setperm_key(key_serial_t id, key_perm_t perm)
917 if (perm & ~(KEY_POS_ALL | KEY_USR_ALL | KEY_GRP_ALL | KEY_OTH_ALL))
920 key_ref = lookup_user_key(id, KEY_LOOKUP_CREATE | KEY_LOOKUP_PARTIAL,
922 if (IS_ERR(key_ref)) {
923 ret = PTR_ERR(key_ref);
927 key = key_ref_to_ptr(key_ref);
929 /* make the changes with the locks held to prevent chown/chmod races */
931 down_write(&key->sem);
933 /* if we're not the sysadmin, we can only change a key that we own */
934 if (capable(CAP_SYS_ADMIN) || uid_eq(key->uid, current_fsuid())) {
946 * Get the destination keyring for instantiation and check that the caller has
947 * Write permission on it.
949 static long get_instantiation_keyring(key_serial_t ringid,
950 struct request_key_auth *rka,
951 struct key **_dest_keyring)
955 *_dest_keyring = NULL;
957 /* just return a NULL pointer if we weren't asked to make a link */
961 /* if a specific keyring is nominated by ID, then use that */
963 dkref = lookup_user_key(ringid, KEY_LOOKUP_CREATE, KEY_NEED_WRITE);
965 return PTR_ERR(dkref);
966 *_dest_keyring = key_ref_to_ptr(dkref);
970 if (ringid == KEY_SPEC_REQKEY_AUTH_KEY)
973 /* otherwise specify the destination keyring recorded in the
974 * authorisation key (any KEY_SPEC_*_KEYRING) */
975 if (ringid >= KEY_SPEC_REQUESTOR_KEYRING) {
976 *_dest_keyring = key_get(rka->dest_keyring);
984 * Change the request_key authorisation key on the current process.
986 static int keyctl_change_reqkey_auth(struct key *key)
990 new = prepare_creds();
994 key_put(new->request_key_auth);
995 new->request_key_auth = key_get(key);
997 return commit_creds(new);
1001 * Instantiate a key with the specified payload and link the key into the
1002 * destination keyring if one is given.
1004 * The caller must have the appropriate instantiation permit set for this to
1005 * work (see keyctl_assume_authority). No other permissions are required.
1007 * If successful, 0 will be returned.
1009 long keyctl_instantiate_key_common(key_serial_t id,
1010 struct iov_iter *from,
1011 key_serial_t ringid)
1013 const struct cred *cred = current_cred();
1014 struct request_key_auth *rka;
1015 struct key *instkey, *dest_keyring;
1016 size_t plen = from ? iov_iter_count(from) : 0;
1020 kenter("%d,,%zu,%d", id, plen, ringid);
1026 if (plen > 1024 * 1024 - 1)
1029 /* the appropriate instantiation authorisation key must have been
1030 * assumed before calling this */
1032 instkey = cred->request_key_auth;
1036 rka = instkey->payload.data;
1037 if (rka->target_key->serial != id)
1040 /* pull the payload in if one was supplied */
1045 payload = kmalloc(plen, GFP_KERNEL);
1047 if (plen <= PAGE_SIZE)
1049 payload = vmalloc(plen);
1055 if (copy_from_iter(payload, plen, from) != plen)
1059 /* find the destination keyring amongst those belonging to the
1060 * requesting task */
1061 ret = get_instantiation_keyring(ringid, rka, &dest_keyring);
1065 /* instantiate the key and link it into a keyring */
1066 ret = key_instantiate_and_link(rka->target_key, payload, plen,
1067 dest_keyring, instkey);
1069 key_put(dest_keyring);
1071 /* discard the assumed authority if it's just been disabled by
1072 * instantiation of the key */
1074 keyctl_change_reqkey_auth(NULL);
1083 * Instantiate a key with the specified payload and link the key into the
1084 * destination keyring if one is given.
1086 * The caller must have the appropriate instantiation permit set for this to
1087 * work (see keyctl_assume_authority). No other permissions are required.
1089 * If successful, 0 will be returned.
1091 long keyctl_instantiate_key(key_serial_t id,
1092 const void __user *_payload,
1094 key_serial_t ringid)
1096 if (_payload && plen) {
1098 struct iov_iter from;
1101 ret = import_single_range(WRITE, (void __user *)_payload, plen,
1106 return keyctl_instantiate_key_common(id, &from, ringid);
1109 return keyctl_instantiate_key_common(id, NULL, ringid);
1113 * Instantiate a key with the specified multipart payload and link the key into
1114 * the destination keyring if one is given.
1116 * The caller must have the appropriate instantiation permit set for this to
1117 * work (see keyctl_assume_authority). No other permissions are required.
1119 * If successful, 0 will be returned.
1121 long keyctl_instantiate_key_iov(key_serial_t id,
1122 const struct iovec __user *_payload_iov,
1124 key_serial_t ringid)
1126 struct iovec iovstack[UIO_FASTIOV], *iov = iovstack;
1127 struct iov_iter from;
1133 ret = import_iovec(WRITE, _payload_iov, ioc,
1134 ARRAY_SIZE(iovstack), &iov, &from);
1137 ret = keyctl_instantiate_key_common(id, &from, 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_NEED_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_NEED_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->session_keyring = key_ref_to_ptr(keyring_r);
1490 init_task_work(newwork, key_change_session_keyring);
1494 write_lock_irq(&tasklist_lock);
1498 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->session_keyring == pcred->session_keyring) {
1518 /* the parent must have the same effective ownership and mustn't be
1520 if (!uid_eq(pcred->uid, mycred->euid) ||
1521 !uid_eq(pcred->euid, mycred->euid) ||
1522 !uid_eq(pcred->suid, mycred->euid) ||
1523 !gid_eq(pcred->gid, mycred->egid) ||
1524 !gid_eq(pcred->egid, mycred->egid) ||
1525 !gid_eq(pcred->sgid, mycred->egid))
1528 /* the keyrings must have the same UID */
1529 if ((pcred->session_keyring &&
1530 !uid_eq(pcred->session_keyring->uid, mycred->euid)) ||
1531 !uid_eq(mycred->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 write_unlock_irq(&tasklist_lock);
1546 put_cred(container_of(oldwork, struct cred, rcu));
1552 key_ref_put(keyring_r);
1557 * The key control system call
1559 SYSCALL_DEFINE5(keyctl, int, option, unsigned long, arg2, unsigned long, arg3,
1560 unsigned long, arg4, unsigned long, arg5)
1563 case KEYCTL_GET_KEYRING_ID:
1564 return keyctl_get_keyring_ID((key_serial_t) arg2,
1567 case KEYCTL_JOIN_SESSION_KEYRING:
1568 return keyctl_join_session_keyring((const char __user *) arg2);
1571 return keyctl_update_key((key_serial_t) arg2,
1572 (const void __user *) arg3,
1576 return keyctl_revoke_key((key_serial_t) arg2);
1578 case KEYCTL_DESCRIBE:
1579 return keyctl_describe_key((key_serial_t) arg2,
1580 (char __user *) arg3,
1584 return keyctl_keyring_clear((key_serial_t) arg2);
1587 return keyctl_keyring_link((key_serial_t) arg2,
1588 (key_serial_t) arg3);
1591 return keyctl_keyring_unlink((key_serial_t) arg2,
1592 (key_serial_t) arg3);
1595 return keyctl_keyring_search((key_serial_t) arg2,
1596 (const char __user *) arg3,
1597 (const char __user *) arg4,
1598 (key_serial_t) arg5);
1601 return keyctl_read_key((key_serial_t) arg2,
1602 (char __user *) arg3,
1606 return keyctl_chown_key((key_serial_t) arg2,
1610 case KEYCTL_SETPERM:
1611 return keyctl_setperm_key((key_serial_t) arg2,
1614 case KEYCTL_INSTANTIATE:
1615 return keyctl_instantiate_key((key_serial_t) arg2,
1616 (const void __user *) arg3,
1618 (key_serial_t) arg5);
1621 return keyctl_negate_key((key_serial_t) arg2,
1623 (key_serial_t) arg4);
1625 case KEYCTL_SET_REQKEY_KEYRING:
1626 return keyctl_set_reqkey_keyring(arg2);
1628 case KEYCTL_SET_TIMEOUT:
1629 return keyctl_set_timeout((key_serial_t) arg2,
1632 case KEYCTL_ASSUME_AUTHORITY:
1633 return keyctl_assume_authority((key_serial_t) arg2);
1635 case KEYCTL_GET_SECURITY:
1636 return keyctl_get_security((key_serial_t) arg2,
1637 (char __user *) arg3,
1640 case KEYCTL_SESSION_TO_PARENT:
1641 return keyctl_session_to_parent();
1644 return keyctl_reject_key((key_serial_t) arg2,
1647 (key_serial_t) arg5);
1649 case KEYCTL_INSTANTIATE_IOV:
1650 return keyctl_instantiate_key_iov(
1651 (key_serial_t) arg2,
1652 (const struct iovec __user *) arg3,
1654 (key_serial_t) arg5);
1656 case KEYCTL_INVALIDATE:
1657 return keyctl_invalidate_key((key_serial_t) arg2);
1659 case KEYCTL_GET_PERSISTENT:
1660 return keyctl_get_persistent((uid_t)arg2, (key_serial_t)arg3);