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 * Copy the iovec data from userspace
1003 static long copy_from_user_iovec(void *buffer, const struct iovec *iov,
1006 for (; ioc > 0; ioc--) {
1007 if (copy_from_user(buffer, iov->iov_base, iov->iov_len) != 0)
1009 buffer += iov->iov_len;
1016 * Instantiate a key with the specified payload and link the key into the
1017 * destination keyring if one is given.
1019 * The caller must have the appropriate instantiation permit set for this to
1020 * work (see keyctl_assume_authority). No other permissions are required.
1022 * If successful, 0 will be returned.
1024 long keyctl_instantiate_key_common(key_serial_t id,
1025 const struct iovec *payload_iov,
1028 key_serial_t ringid)
1030 const struct cred *cred = current_cred();
1031 struct request_key_auth *rka;
1032 struct key *instkey, *dest_keyring;
1037 kenter("%d,,%zu,%d", id, plen, ringid);
1040 if (plen > 1024 * 1024 - 1)
1043 /* the appropriate instantiation authorisation key must have been
1044 * assumed before calling this */
1046 instkey = cred->request_key_auth;
1050 rka = instkey->payload.data;
1051 if (rka->target_key->serial != id)
1054 /* pull the payload in if one was supplied */
1059 payload = kmalloc(plen, GFP_KERNEL);
1061 if (plen <= PAGE_SIZE)
1064 payload = vmalloc(plen);
1069 ret = copy_from_user_iovec(payload, payload_iov, ioc);
1074 /* find the destination keyring amongst those belonging to the
1075 * requesting task */
1076 ret = get_instantiation_keyring(ringid, rka, &dest_keyring);
1080 /* instantiate the key and link it into a keyring */
1081 ret = key_instantiate_and_link(rka->target_key, payload, plen,
1082 dest_keyring, instkey);
1084 key_put(dest_keyring);
1086 /* discard the assumed authority if it's just been disabled by
1087 * instantiation of the key */
1089 keyctl_change_reqkey_auth(NULL);
1101 * Instantiate a key with the specified payload and link the key into the
1102 * destination keyring if one is given.
1104 * The caller must have the appropriate instantiation permit set for this to
1105 * work (see keyctl_assume_authority). No other permissions are required.
1107 * If successful, 0 will be returned.
1109 long keyctl_instantiate_key(key_serial_t id,
1110 const void __user *_payload,
1112 key_serial_t ringid)
1114 if (_payload && plen) {
1115 struct iovec iov[1] = {
1116 [0].iov_base = (void __user *)_payload,
1120 return keyctl_instantiate_key_common(id, iov, 1, plen, ringid);
1123 return keyctl_instantiate_key_common(id, NULL, 0, 0, ringid);
1127 * Instantiate a key with the specified multipart payload and link the key into
1128 * the destination keyring if one is given.
1130 * The caller must have the appropriate instantiation permit set for this to
1131 * work (see keyctl_assume_authority). No other permissions are required.
1133 * If successful, 0 will be returned.
1135 long keyctl_instantiate_key_iov(key_serial_t id,
1136 const struct iovec __user *_payload_iov,
1138 key_serial_t ringid)
1140 struct iovec iovstack[UIO_FASTIOV], *iov = iovstack;
1143 if (!_payload_iov || !ioc)
1146 ret = rw_copy_check_uvector(WRITE, _payload_iov, ioc,
1147 ARRAY_SIZE(iovstack), iovstack, &iov);
1151 goto no_payload_free;
1153 ret = keyctl_instantiate_key_common(id, iov, ioc, ret, ringid);
1155 if (iov != iovstack)
1160 if (iov != iovstack)
1163 return keyctl_instantiate_key_common(id, NULL, 0, 0, ringid);
1167 * Negatively instantiate the key with the given timeout (in seconds) and link
1168 * the key into the destination keyring if one is given.
1170 * The caller must have the appropriate instantiation permit set for this to
1171 * work (see keyctl_assume_authority). No other permissions are required.
1173 * The key and any links to the key will be automatically garbage collected
1174 * after the timeout expires.
1176 * Negative keys are used to rate limit repeated request_key() calls by causing
1177 * them to return -ENOKEY until the negative key expires.
1179 * If successful, 0 will be returned.
1181 long keyctl_negate_key(key_serial_t id, unsigned timeout, key_serial_t ringid)
1183 return keyctl_reject_key(id, timeout, ENOKEY, ringid);
1187 * Negatively instantiate the key with the given timeout (in seconds) and error
1188 * code and link the key into the destination keyring if one is given.
1190 * The caller must have the appropriate instantiation permit set for this to
1191 * work (see keyctl_assume_authority). No other permissions are required.
1193 * The key and any links to the key will be automatically garbage collected
1194 * after the timeout expires.
1196 * Negative keys are used to rate limit repeated request_key() calls by causing
1197 * them to return the specified error code until the negative key expires.
1199 * If successful, 0 will be returned.
1201 long keyctl_reject_key(key_serial_t id, unsigned timeout, unsigned error,
1202 key_serial_t ringid)
1204 const struct cred *cred = current_cred();
1205 struct request_key_auth *rka;
1206 struct key *instkey, *dest_keyring;
1209 kenter("%d,%u,%u,%d", id, timeout, error, ringid);
1211 /* must be a valid error code and mustn't be a kernel special */
1213 error >= MAX_ERRNO ||
1214 error == ERESTARTSYS ||
1215 error == ERESTARTNOINTR ||
1216 error == ERESTARTNOHAND ||
1217 error == ERESTART_RESTARTBLOCK)
1220 /* the appropriate instantiation authorisation key must have been
1221 * assumed before calling this */
1223 instkey = cred->request_key_auth;
1227 rka = instkey->payload.data;
1228 if (rka->target_key->serial != id)
1231 /* find the destination keyring if present (which must also be
1233 ret = get_instantiation_keyring(ringid, rka, &dest_keyring);
1237 /* instantiate the key and link it into a keyring */
1238 ret = key_reject_and_link(rka->target_key, timeout, error,
1239 dest_keyring, instkey);
1241 key_put(dest_keyring);
1243 /* discard the assumed authority if it's just been disabled by
1244 * instantiation of the key */
1246 keyctl_change_reqkey_auth(NULL);
1253 * Read or set the default keyring in which request_key() will cache keys and
1254 * return the old setting.
1256 * If a process keyring is specified then this will be created if it doesn't
1257 * yet exist. The old setting will be returned if successful.
1259 long keyctl_set_reqkey_keyring(int reqkey_defl)
1262 int ret, old_setting;
1264 old_setting = current_cred_xxx(jit_keyring);
1266 if (reqkey_defl == KEY_REQKEY_DEFL_NO_CHANGE)
1269 new = prepare_creds();
1273 switch (reqkey_defl) {
1274 case KEY_REQKEY_DEFL_THREAD_KEYRING:
1275 ret = install_thread_keyring_to_cred(new);
1280 case KEY_REQKEY_DEFL_PROCESS_KEYRING:
1281 ret = install_process_keyring_to_cred(new);
1289 case KEY_REQKEY_DEFL_DEFAULT:
1290 case KEY_REQKEY_DEFL_SESSION_KEYRING:
1291 case KEY_REQKEY_DEFL_USER_KEYRING:
1292 case KEY_REQKEY_DEFL_USER_SESSION_KEYRING:
1293 case KEY_REQKEY_DEFL_REQUESTOR_KEYRING:
1296 case KEY_REQKEY_DEFL_NO_CHANGE:
1297 case KEY_REQKEY_DEFL_GROUP_KEYRING:
1304 new->jit_keyring = reqkey_defl;
1313 * Set or clear the timeout on a key.
1315 * Either the key must grant the caller Setattr permission or else the caller
1316 * must hold an instantiation authorisation token for the key.
1318 * The timeout is either 0 to clear the timeout, or a number of seconds from
1319 * the current time. The key and any links to the key will be automatically
1320 * garbage collected after the timeout expires.
1322 * If successful, 0 is returned.
1324 long keyctl_set_timeout(key_serial_t id, unsigned timeout)
1326 struct key *key, *instkey;
1330 key_ref = lookup_user_key(id, KEY_LOOKUP_CREATE | KEY_LOOKUP_PARTIAL,
1332 if (IS_ERR(key_ref)) {
1333 /* setting the timeout on a key under construction is permitted
1334 * if we have the authorisation token handy */
1335 if (PTR_ERR(key_ref) == -EACCES) {
1336 instkey = key_get_instantiation_authkey(id);
1337 if (!IS_ERR(instkey)) {
1339 key_ref = lookup_user_key(id,
1342 if (!IS_ERR(key_ref))
1347 ret = PTR_ERR(key_ref);
1352 key = key_ref_to_ptr(key_ref);
1353 key_set_timeout(key, timeout);
1362 * Assume (or clear) the authority to instantiate the specified key.
1364 * This sets the authoritative token currently in force for key instantiation.
1365 * This must be done for a key to be instantiated. It has the effect of making
1366 * available all the keys from the caller of the request_key() that created a
1367 * key to request_key() calls made by the caller of this function.
1369 * The caller must have the instantiation key in their process keyrings with a
1370 * Search permission grant available to the caller.
1372 * If the ID given is 0, then the setting will be cleared and 0 returned.
1374 * If the ID given has a matching an authorisation key, then that key will be
1375 * set and its ID will be returned. The authorisation key can be read to get
1376 * the callout information passed to request_key().
1378 long keyctl_assume_authority(key_serial_t id)
1380 struct key *authkey;
1383 /* special key IDs aren't permitted */
1388 /* we divest ourselves of authority if given an ID of 0 */
1390 ret = keyctl_change_reqkey_auth(NULL);
1394 /* attempt to assume the authority temporarily granted to us whilst we
1395 * instantiate the specified key
1396 * - the authorisation key must be in the current task's keyrings
1399 authkey = key_get_instantiation_authkey(id);
1400 if (IS_ERR(authkey)) {
1401 ret = PTR_ERR(authkey);
1405 ret = keyctl_change_reqkey_auth(authkey);
1410 ret = authkey->serial;
1416 * Get a key's the LSM security label.
1418 * The key must grant the caller View permission for this to work.
1420 * If there's a buffer, then up to buflen bytes of data will be placed into it.
1422 * If successful, the amount of information available will be returned,
1423 * irrespective of how much was copied (including the terminal NUL).
1425 long keyctl_get_security(key_serial_t keyid,
1426 char __user *buffer,
1429 struct key *key, *instkey;
1434 key_ref = lookup_user_key(keyid, KEY_LOOKUP_PARTIAL, KEY_NEED_VIEW);
1435 if (IS_ERR(key_ref)) {
1436 if (PTR_ERR(key_ref) != -EACCES)
1437 return PTR_ERR(key_ref);
1439 /* viewing a key under construction is also permitted if we
1440 * have the authorisation token handy */
1441 instkey = key_get_instantiation_authkey(keyid);
1442 if (IS_ERR(instkey))
1443 return PTR_ERR(instkey);
1446 key_ref = lookup_user_key(keyid, KEY_LOOKUP_PARTIAL, 0);
1447 if (IS_ERR(key_ref))
1448 return PTR_ERR(key_ref);
1451 key = key_ref_to_ptr(key_ref);
1452 ret = security_key_getsecurity(key, &context);
1454 /* if no information was returned, give userspace an empty
1457 if (buffer && buflen > 0 &&
1458 copy_to_user(buffer, "", 1) != 0)
1460 } else if (ret > 0) {
1461 /* return as much data as there's room for */
1462 if (buffer && buflen > 0) {
1466 if (copy_to_user(buffer, context, buflen) != 0)
1473 key_ref_put(key_ref);
1478 * Attempt to install the calling process's session keyring on the process's
1481 * The keyring must exist and must grant the caller LINK permission, and the
1482 * parent process must be single-threaded and must have the same effective
1483 * ownership as this process and mustn't be SUID/SGID.
1485 * The keyring will be emplaced on the parent when it next resumes userspace.
1487 * If successful, 0 will be returned.
1489 long keyctl_session_to_parent(void)
1491 struct task_struct *me, *parent;
1492 const struct cred *mycred, *pcred;
1493 struct callback_head *newwork, *oldwork;
1494 key_ref_t keyring_r;
1498 keyring_r = lookup_user_key(KEY_SPEC_SESSION_KEYRING, 0, KEY_NEED_LINK);
1499 if (IS_ERR(keyring_r))
1500 return PTR_ERR(keyring_r);
1504 /* our parent is going to need a new cred struct, a new tgcred struct
1505 * and new security data, so we allocate them here to prevent ENOMEM in
1507 cred = cred_alloc_blank();
1510 newwork = &cred->rcu;
1512 cred->session_keyring = key_ref_to_ptr(keyring_r);
1514 init_task_work(newwork, key_change_session_keyring);
1518 write_lock_irq(&tasklist_lock);
1522 parent = me->real_parent;
1524 /* the parent mustn't be init and mustn't be a kernel thread */
1525 if (parent->pid <= 1 || !parent->mm)
1528 /* the parent must be single threaded */
1529 if (!thread_group_empty(parent))
1532 /* the parent and the child must have different session keyrings or
1533 * there's no point */
1534 mycred = current_cred();
1535 pcred = __task_cred(parent);
1536 if (mycred == pcred ||
1537 mycred->session_keyring == pcred->session_keyring) {
1542 /* the parent must have the same effective ownership and mustn't be
1544 if (!uid_eq(pcred->uid, mycred->euid) ||
1545 !uid_eq(pcred->euid, mycred->euid) ||
1546 !uid_eq(pcred->suid, mycred->euid) ||
1547 !gid_eq(pcred->gid, mycred->egid) ||
1548 !gid_eq(pcred->egid, mycred->egid) ||
1549 !gid_eq(pcred->sgid, mycred->egid))
1552 /* the keyrings must have the same UID */
1553 if ((pcred->session_keyring &&
1554 !uid_eq(pcred->session_keyring->uid, mycred->euid)) ||
1555 !uid_eq(mycred->session_keyring->uid, mycred->euid))
1558 /* cancel an already pending keyring replacement */
1559 oldwork = task_work_cancel(parent, key_change_session_keyring);
1561 /* the replacement session keyring is applied just prior to userspace
1563 ret = task_work_add(parent, newwork, true);
1567 write_unlock_irq(&tasklist_lock);
1570 put_cred(container_of(oldwork, struct cred, rcu));
1576 key_ref_put(keyring_r);
1581 * The key control system call
1583 SYSCALL_DEFINE5(keyctl, int, option, unsigned long, arg2, unsigned long, arg3,
1584 unsigned long, arg4, unsigned long, arg5)
1587 case KEYCTL_GET_KEYRING_ID:
1588 return keyctl_get_keyring_ID((key_serial_t) arg2,
1591 case KEYCTL_JOIN_SESSION_KEYRING:
1592 return keyctl_join_session_keyring((const char __user *) arg2);
1595 return keyctl_update_key((key_serial_t) arg2,
1596 (const void __user *) arg3,
1600 return keyctl_revoke_key((key_serial_t) arg2);
1602 case KEYCTL_DESCRIBE:
1603 return keyctl_describe_key((key_serial_t) arg2,
1604 (char __user *) arg3,
1608 return keyctl_keyring_clear((key_serial_t) arg2);
1611 return keyctl_keyring_link((key_serial_t) arg2,
1612 (key_serial_t) arg3);
1615 return keyctl_keyring_unlink((key_serial_t) arg2,
1616 (key_serial_t) arg3);
1619 return keyctl_keyring_search((key_serial_t) arg2,
1620 (const char __user *) arg3,
1621 (const char __user *) arg4,
1622 (key_serial_t) arg5);
1625 return keyctl_read_key((key_serial_t) arg2,
1626 (char __user *) arg3,
1630 return keyctl_chown_key((key_serial_t) arg2,
1634 case KEYCTL_SETPERM:
1635 return keyctl_setperm_key((key_serial_t) arg2,
1638 case KEYCTL_INSTANTIATE:
1639 return keyctl_instantiate_key((key_serial_t) arg2,
1640 (const void __user *) arg3,
1642 (key_serial_t) arg5);
1645 return keyctl_negate_key((key_serial_t) arg2,
1647 (key_serial_t) arg4);
1649 case KEYCTL_SET_REQKEY_KEYRING:
1650 return keyctl_set_reqkey_keyring(arg2);
1652 case KEYCTL_SET_TIMEOUT:
1653 return keyctl_set_timeout((key_serial_t) arg2,
1656 case KEYCTL_ASSUME_AUTHORITY:
1657 return keyctl_assume_authority((key_serial_t) arg2);
1659 case KEYCTL_GET_SECURITY:
1660 return keyctl_get_security((key_serial_t) arg2,
1661 (char __user *) arg3,
1664 case KEYCTL_SESSION_TO_PARENT:
1665 return keyctl_session_to_parent();
1668 return keyctl_reject_key((key_serial_t) arg2,
1671 (key_serial_t) arg5);
1673 case KEYCTL_INSTANTIATE_IOV:
1674 return keyctl_instantiate_key_iov(
1675 (key_serial_t) arg2,
1676 (const struct iovec __user *) arg3,
1678 (key_serial_t) arg5);
1680 case KEYCTL_INVALIDATE:
1681 return keyctl_invalidate_key((key_serial_t) arg2);
1683 case KEYCTL_GET_PERSISTENT:
1684 return keyctl_get_persistent((uid_t)arg2, (key_serial_t)arg3);