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;
72 if (plen > 1024 * 1024 - 1)
75 /* draw all the data into kernel space */
76 ret = key_get_type_from_user(type, _type, sizeof(type));
82 description = strndup_user(_description, KEY_MAX_DESC_SIZE);
83 if (IS_ERR(description)) {
84 ret = PTR_ERR(description);
90 } else if ((description[0] == '.') &&
91 (strncmp(type, "keyring", 7) == 0)) {
97 /* pull the payload in if one was supplied */
102 payload = kmalloc(plen, GFP_KERNEL | __GFP_NOWARN);
104 if (plen <= PAGE_SIZE)
106 payload = vmalloc(plen);
112 if (copy_from_user(payload, _payload, plen) != 0)
116 /* find the target keyring (which must be writable) */
117 keyring_ref = lookup_user_key(ringid, KEY_LOOKUP_CREATE, KEY_NEED_WRITE);
118 if (IS_ERR(keyring_ref)) {
119 ret = PTR_ERR(keyring_ref);
123 /* create or update the requested key and add it to the target
125 key_ref = key_create_or_update(keyring_ref, type, description,
126 payload, plen, KEY_PERM_UNDEF,
128 if (!IS_ERR(key_ref)) {
129 ret = key_ref_to_ptr(key_ref)->serial;
130 key_ref_put(key_ref);
133 ret = PTR_ERR(key_ref);
136 key_ref_put(keyring_ref);
146 * Search the process keyrings and keyring trees linked from those for a
147 * matching key. Keyrings must have appropriate Search permission to be
150 * If a key is found, it will be attached to the destination keyring if there's
151 * one specified and the serial number of the key will be returned.
153 * If no key is found, /sbin/request-key will be invoked if _callout_info is
154 * non-NULL in an attempt to create a key. The _callout_info string will be
155 * passed to /sbin/request-key to aid with completing the request. If the
156 * _callout_info string is "" then it will be changed to "-".
158 SYSCALL_DEFINE4(request_key, const char __user *, _type,
159 const char __user *, _description,
160 const char __user *, _callout_info,
161 key_serial_t, destringid)
163 struct key_type *ktype;
167 char type[32], *description, *callout_info;
170 /* pull the type into kernel space */
171 ret = key_get_type_from_user(type, _type, sizeof(type));
175 /* pull the description into kernel space */
176 description = strndup_user(_description, KEY_MAX_DESC_SIZE);
177 if (IS_ERR(description)) {
178 ret = PTR_ERR(description);
182 /* pull the callout info into kernel space */
186 callout_info = strndup_user(_callout_info, PAGE_SIZE);
187 if (IS_ERR(callout_info)) {
188 ret = PTR_ERR(callout_info);
191 callout_len = strlen(callout_info);
194 /* get the destination keyring if specified */
197 dest_ref = lookup_user_key(destringid, KEY_LOOKUP_CREATE,
199 if (IS_ERR(dest_ref)) {
200 ret = PTR_ERR(dest_ref);
205 /* find the key type */
206 ktype = key_type_lookup(type);
208 ret = PTR_ERR(ktype);
213 key = request_key_and_link(ktype, description, callout_info,
214 callout_len, NULL, key_ref_to_ptr(dest_ref),
221 /* wait for the key to finish being constructed */
222 ret = wait_for_key_construction(key, 1);
233 key_ref_put(dest_ref);
243 * Get the ID of the specified process keyring.
245 * The requested keyring must have search permission to be found.
247 * If successful, the ID of the requested keyring will be returned.
249 long keyctl_get_keyring_ID(key_serial_t id, int create)
252 unsigned long lflags;
255 lflags = create ? KEY_LOOKUP_CREATE : 0;
256 key_ref = lookup_user_key(id, lflags, KEY_NEED_SEARCH);
257 if (IS_ERR(key_ref)) {
258 ret = PTR_ERR(key_ref);
262 ret = key_ref_to_ptr(key_ref)->serial;
263 key_ref_put(key_ref);
269 * Join a (named) session keyring.
271 * Create and join an anonymous session keyring or join a named session
272 * keyring, creating it if necessary. A named session keyring must have Search
273 * permission for it to be joined. Session keyrings without this permit will
274 * be skipped over. It is not permitted for userspace to create or join
275 * keyrings whose name begin with a dot.
277 * If successful, the ID of the joined session keyring will be returned.
279 long keyctl_join_session_keyring(const char __user *_name)
284 /* fetch the name from userspace */
287 name = strndup_user(_name, KEY_MAX_DESC_SIZE);
298 /* join the session */
299 ret = join_session_keyring(name);
307 * Update a key's data payload from the given data.
309 * The key must grant the caller Write permission and the key type must support
310 * updating for this to work. A negative key can be positively instantiated
313 * If successful, 0 will be returned. If the key type does not support
314 * updating, then -EOPNOTSUPP will be returned.
316 long keyctl_update_key(key_serial_t id,
317 const void __user *_payload,
325 if (plen > PAGE_SIZE)
328 /* pull the payload in if one was supplied */
332 payload = kmalloc(plen, GFP_KERNEL);
337 if (copy_from_user(payload, _payload, plen) != 0)
341 /* find the target key (which must be writable) */
342 key_ref = lookup_user_key(id, 0, KEY_NEED_WRITE);
343 if (IS_ERR(key_ref)) {
344 ret = PTR_ERR(key_ref);
349 ret = key_update(key_ref, payload, plen);
351 key_ref_put(key_ref);
361 * The key must be grant the caller Write or Setattr permission for this to
362 * work. The key type should give up its quota claim when revoked. The key
363 * and any links to the key will be automatically garbage collected after a
364 * certain amount of time (/proc/sys/kernel/keys/gc_delay).
366 * If successful, 0 is returned.
368 long keyctl_revoke_key(key_serial_t id)
373 key_ref = lookup_user_key(id, 0, KEY_NEED_WRITE);
374 if (IS_ERR(key_ref)) {
375 ret = PTR_ERR(key_ref);
378 key_ref = lookup_user_key(id, 0, KEY_NEED_SETATTR);
379 if (IS_ERR(key_ref)) {
380 ret = PTR_ERR(key_ref);
385 key_revoke(key_ref_to_ptr(key_ref));
388 key_ref_put(key_ref);
396 * The key must be grant the caller Invalidate permission for this to work.
397 * The key and any links to the key will be automatically garbage collected
400 * If successful, 0 is returned.
402 long keyctl_invalidate_key(key_serial_t id)
409 key_ref = lookup_user_key(id, 0, KEY_NEED_SEARCH);
410 if (IS_ERR(key_ref)) {
411 ret = PTR_ERR(key_ref);
413 /* Root is permitted to invalidate certain special keys */
414 if (capable(CAP_SYS_ADMIN)) {
415 key_ref = lookup_user_key(id, 0, 0);
418 if (test_bit(KEY_FLAG_ROOT_CAN_INVAL,
419 &key_ref_to_ptr(key_ref)->flags))
428 key_invalidate(key_ref_to_ptr(key_ref));
431 key_ref_put(key_ref);
433 kleave(" = %ld", ret);
438 * Clear the specified keyring, creating an empty process keyring if one of the
439 * special keyring IDs is used.
441 * The keyring must grant the caller Write permission for this to work. If
442 * successful, 0 will be returned.
444 long keyctl_keyring_clear(key_serial_t ringid)
446 key_ref_t keyring_ref;
449 keyring_ref = lookup_user_key(ringid, KEY_LOOKUP_CREATE, KEY_NEED_WRITE);
450 if (IS_ERR(keyring_ref)) {
451 ret = PTR_ERR(keyring_ref);
453 /* Root is permitted to invalidate certain special keyrings */
454 if (capable(CAP_SYS_ADMIN)) {
455 keyring_ref = lookup_user_key(ringid, 0, 0);
456 if (IS_ERR(keyring_ref))
458 if (test_bit(KEY_FLAG_ROOT_CAN_CLEAR,
459 &key_ref_to_ptr(keyring_ref)->flags))
468 ret = keyring_clear(key_ref_to_ptr(keyring_ref));
470 key_ref_put(keyring_ref);
476 * Create a link from a keyring to a key if there's no matching key in the
477 * keyring, otherwise replace the link to the matching key with a link to the
480 * The key must grant the caller Link permission and the the keyring must grant
481 * the caller Write permission. Furthermore, if an additional link is created,
482 * the keyring's quota will be extended.
484 * If successful, 0 will be returned.
486 long keyctl_keyring_link(key_serial_t id, key_serial_t ringid)
488 key_ref_t keyring_ref, key_ref;
491 keyring_ref = lookup_user_key(ringid, KEY_LOOKUP_CREATE, KEY_NEED_WRITE);
492 if (IS_ERR(keyring_ref)) {
493 ret = PTR_ERR(keyring_ref);
497 key_ref = lookup_user_key(id, KEY_LOOKUP_CREATE, KEY_NEED_LINK);
498 if (IS_ERR(key_ref)) {
499 ret = PTR_ERR(key_ref);
503 ret = key_link(key_ref_to_ptr(keyring_ref), key_ref_to_ptr(key_ref));
505 key_ref_put(key_ref);
507 key_ref_put(keyring_ref);
513 * Unlink a key from a keyring.
515 * The keyring must grant the caller Write permission for this to work; the key
516 * itself need not grant the caller anything. If the last link to a key is
517 * removed then that key will be scheduled for destruction.
519 * If successful, 0 will be returned.
521 long keyctl_keyring_unlink(key_serial_t id, key_serial_t ringid)
523 key_ref_t keyring_ref, key_ref;
526 keyring_ref = lookup_user_key(ringid, 0, KEY_NEED_WRITE);
527 if (IS_ERR(keyring_ref)) {
528 ret = PTR_ERR(keyring_ref);
532 key_ref = lookup_user_key(id, KEY_LOOKUP_FOR_UNLINK, 0);
533 if (IS_ERR(key_ref)) {
534 ret = PTR_ERR(key_ref);
538 ret = key_unlink(key_ref_to_ptr(keyring_ref), key_ref_to_ptr(key_ref));
540 key_ref_put(key_ref);
542 key_ref_put(keyring_ref);
548 * Return a description of a key to userspace.
550 * The key must grant the caller View permission for this to work.
552 * If there's a buffer, we place up to buflen bytes of data into it formatted
553 * in the following way:
555 * type;uid;gid;perm;description<NUL>
557 * If successful, we return the amount of description available, irrespective
558 * of how much we may have copied into the buffer.
560 long keyctl_describe_key(key_serial_t keyid,
564 struct key *key, *instkey;
568 int desclen, infolen;
570 key_ref = lookup_user_key(keyid, KEY_LOOKUP_PARTIAL, KEY_NEED_VIEW);
571 if (IS_ERR(key_ref)) {
572 /* viewing a key under construction is permitted if we have the
573 * authorisation token handy */
574 if (PTR_ERR(key_ref) == -EACCES) {
575 instkey = key_get_instantiation_authkey(keyid);
576 if (!IS_ERR(instkey)) {
578 key_ref = lookup_user_key(keyid,
581 if (!IS_ERR(key_ref))
586 ret = PTR_ERR(key_ref);
591 key = key_ref_to_ptr(key_ref);
592 desclen = strlen(key->description);
594 /* calculate how much information we're going to return */
596 infobuf = kasprintf(GFP_KERNEL,
599 from_kuid_munged(current_user_ns(), key->uid),
600 from_kgid_munged(current_user_ns(), key->gid),
604 infolen = strlen(infobuf);
605 ret = infolen + desclen + 1;
607 /* consider returning the data */
608 if (buffer && buflen >= ret) {
609 if (copy_to_user(buffer, infobuf, infolen) != 0 ||
610 copy_to_user(buffer + infolen, key->description,
617 key_ref_put(key_ref);
623 * Search the specified keyring and any keyrings it links to for a matching
624 * key. Only keyrings that grant the caller Search permission will be searched
625 * (this includes the starting keyring). Only keys with Search permission can
628 * If successful, the found key will be linked to the destination keyring if
629 * supplied and the key has Link permission, and the found key ID will be
632 long keyctl_keyring_search(key_serial_t ringid,
633 const char __user *_type,
634 const char __user *_description,
635 key_serial_t destringid)
637 struct key_type *ktype;
638 key_ref_t keyring_ref, key_ref, dest_ref;
639 char type[32], *description;
642 /* pull the type and description into kernel space */
643 ret = key_get_type_from_user(type, _type, sizeof(type));
647 description = strndup_user(_description, KEY_MAX_DESC_SIZE);
648 if (IS_ERR(description)) {
649 ret = PTR_ERR(description);
653 /* get the keyring at which to begin the search */
654 keyring_ref = lookup_user_key(ringid, 0, KEY_NEED_SEARCH);
655 if (IS_ERR(keyring_ref)) {
656 ret = PTR_ERR(keyring_ref);
660 /* get the destination keyring if specified */
663 dest_ref = lookup_user_key(destringid, KEY_LOOKUP_CREATE,
665 if (IS_ERR(dest_ref)) {
666 ret = PTR_ERR(dest_ref);
671 /* find the key type */
672 ktype = key_type_lookup(type);
674 ret = PTR_ERR(ktype);
679 key_ref = keyring_search(keyring_ref, ktype, description);
680 if (IS_ERR(key_ref)) {
681 ret = PTR_ERR(key_ref);
683 /* treat lack or presence of a negative key the same */
689 /* link the resulting key to the destination keyring if we can */
691 ret = key_permission(key_ref, KEY_NEED_LINK);
695 ret = key_link(key_ref_to_ptr(dest_ref), key_ref_to_ptr(key_ref));
700 ret = key_ref_to_ptr(key_ref)->serial;
703 key_ref_put(key_ref);
707 key_ref_put(dest_ref);
709 key_ref_put(keyring_ref);
717 * Read a key's payload.
719 * The key must either grant the caller Read permission, or it must grant the
720 * caller Search permission when searched for from the process keyrings.
722 * If successful, we place up to buflen bytes of data into the buffer, if one
723 * is provided, and return the amount of data that is available in the key,
724 * irrespective of how much we copied into the buffer.
726 long keyctl_read_key(key_serial_t keyid, char __user *buffer, size_t buflen)
732 /* find the key first */
733 key_ref = lookup_user_key(keyid, 0, 0);
734 if (IS_ERR(key_ref)) {
739 key = key_ref_to_ptr(key_ref);
741 ret = key_read_state(key);
743 goto error2; /* Negatively instantiated */
745 /* see if we can read it directly */
746 ret = key_permission(key_ref, KEY_NEED_READ);
752 /* we can't; see if it's searchable from this process's keyrings
753 * - we automatically take account of the fact that it may be
754 * dangling off an instantiation key
756 if (!is_key_possessed(key_ref)) {
761 /* the key is probably readable - now try to read it */
764 if (key->type->read) {
765 /* Read the data with the semaphore held (since we might sleep)
766 * to protect against the key being updated or revoked.
768 down_read(&key->sem);
769 ret = key_validate(key);
771 ret = key->type->read(key, buffer, buflen);
782 * Change the ownership of a key
784 * The key must grant the caller Setattr permission for this to work, though
785 * the key need not be fully instantiated yet. For the UID to be changed, or
786 * for the GID to be changed to a group the caller is not a member of, the
787 * caller must have sysadmin capability. If either uid or gid is -1 then that
788 * attribute is not changed.
790 * If the UID is to be changed, the new user must have sufficient quota to
791 * accept the key. The quota deduction will be removed from the old user to
792 * the new user should the attribute be changed.
794 * If successful, 0 will be returned.
796 long keyctl_chown_key(key_serial_t id, uid_t user, gid_t group)
798 struct key_user *newowner, *zapowner = NULL;
805 uid = make_kuid(current_user_ns(), user);
806 gid = make_kgid(current_user_ns(), group);
808 if ((user != (uid_t) -1) && !uid_valid(uid))
810 if ((group != (gid_t) -1) && !gid_valid(gid))
814 if (user == (uid_t) -1 && group == (gid_t) -1)
817 key_ref = lookup_user_key(id, KEY_LOOKUP_CREATE | KEY_LOOKUP_PARTIAL,
819 if (IS_ERR(key_ref)) {
820 ret = PTR_ERR(key_ref);
824 key = key_ref_to_ptr(key_ref);
826 /* make the changes with the locks held to prevent chown/chown races */
828 down_write(&key->sem);
830 if (!capable(CAP_SYS_ADMIN)) {
831 /* only the sysadmin can chown a key to some other UID */
832 if (user != (uid_t) -1 && !uid_eq(key->uid, uid))
835 /* only the sysadmin can set the key's GID to a group other
836 * than one of those that the current process subscribes to */
837 if (group != (gid_t) -1 && !gid_eq(gid, key->gid) && !in_group_p(gid))
842 if (user != (uid_t) -1 && !uid_eq(uid, key->uid)) {
844 newowner = key_user_lookup(uid);
848 /* transfer the quota burden to the new user */
849 if (test_bit(KEY_FLAG_IN_QUOTA, &key->flags)) {
850 unsigned maxkeys = uid_eq(uid, GLOBAL_ROOT_UID) ?
851 key_quota_root_maxkeys : key_quota_maxkeys;
852 unsigned maxbytes = uid_eq(uid, GLOBAL_ROOT_UID) ?
853 key_quota_root_maxbytes : key_quota_maxbytes;
855 spin_lock(&newowner->lock);
856 if (newowner->qnkeys + 1 > maxkeys ||
857 newowner->qnbytes + key->quotalen > maxbytes ||
858 newowner->qnbytes + key->quotalen <
863 newowner->qnbytes += key->quotalen;
864 spin_unlock(&newowner->lock);
866 spin_lock(&key->user->lock);
868 key->user->qnbytes -= key->quotalen;
869 spin_unlock(&key->user->lock);
872 atomic_dec(&key->user->nkeys);
873 atomic_inc(&newowner->nkeys);
875 if (key->state != KEY_IS_UNINSTANTIATED) {
876 atomic_dec(&key->user->nikeys);
877 atomic_inc(&newowner->nikeys);
880 zapowner = key->user;
881 key->user = newowner;
886 if (group != (gid_t) -1)
895 key_user_put(zapowner);
900 spin_unlock(&newowner->lock);
907 * Change the permission mask on a key.
909 * The key must grant the caller Setattr permission for this to work, though
910 * the key need not be fully instantiated yet. If the caller does not have
911 * sysadmin capability, it may only change the permission on keys that it owns.
913 long keyctl_setperm_key(key_serial_t id, key_perm_t perm)
920 if (perm & ~(KEY_POS_ALL | KEY_USR_ALL | KEY_GRP_ALL | KEY_OTH_ALL))
923 key_ref = lookup_user_key(id, KEY_LOOKUP_CREATE | KEY_LOOKUP_PARTIAL,
925 if (IS_ERR(key_ref)) {
926 ret = PTR_ERR(key_ref);
930 key = key_ref_to_ptr(key_ref);
932 /* make the changes with the locks held to prevent chown/chmod races */
934 down_write(&key->sem);
936 /* if we're not the sysadmin, we can only change a key that we own */
937 if (capable(CAP_SYS_ADMIN) || uid_eq(key->uid, current_fsuid())) {
949 * Get the destination keyring for instantiation and check that the caller has
950 * Write permission on it.
952 static long get_instantiation_keyring(key_serial_t ringid,
953 struct request_key_auth *rka,
954 struct key **_dest_keyring)
958 *_dest_keyring = NULL;
960 /* just return a NULL pointer if we weren't asked to make a link */
964 /* if a specific keyring is nominated by ID, then use that */
966 dkref = lookup_user_key(ringid, KEY_LOOKUP_CREATE, KEY_NEED_WRITE);
968 return PTR_ERR(dkref);
969 *_dest_keyring = key_ref_to_ptr(dkref);
973 if (ringid == KEY_SPEC_REQKEY_AUTH_KEY)
976 /* otherwise specify the destination keyring recorded in the
977 * authorisation key (any KEY_SPEC_*_KEYRING) */
978 if (ringid >= KEY_SPEC_REQUESTOR_KEYRING) {
979 *_dest_keyring = key_get(rka->dest_keyring);
987 * Change the request_key authorisation key on the current process.
989 static int keyctl_change_reqkey_auth(struct key *key)
993 new = prepare_creds();
997 key_put(new->request_key_auth);
998 new->request_key_auth = key_get(key);
1000 return commit_creds(new);
1004 * Instantiate a key with the specified payload and link the key into the
1005 * destination keyring if one is given.
1007 * The caller must have the appropriate instantiation permit set for this to
1008 * work (see keyctl_assume_authority). No other permissions are required.
1010 * If successful, 0 will be returned.
1012 long keyctl_instantiate_key_common(key_serial_t id,
1013 struct iov_iter *from,
1014 key_serial_t ringid)
1016 const struct cred *cred = current_cred();
1017 struct request_key_auth *rka;
1018 struct key *instkey, *dest_keyring;
1019 size_t plen = from ? iov_iter_count(from) : 0;
1023 kenter("%d,,%zu,%d", id, plen, ringid);
1029 if (plen > 1024 * 1024 - 1)
1032 /* the appropriate instantiation authorisation key must have been
1033 * assumed before calling this */
1035 instkey = cred->request_key_auth;
1039 rka = instkey->payload.data[0];
1040 if (rka->target_key->serial != id)
1043 /* pull the payload in if one was supplied */
1048 payload = kmalloc(plen, GFP_KERNEL);
1050 if (plen <= PAGE_SIZE)
1052 payload = vmalloc(plen);
1058 if (copy_from_iter(payload, plen, from) != plen)
1062 /* find the destination keyring amongst those belonging to the
1063 * requesting task */
1064 ret = get_instantiation_keyring(ringid, rka, &dest_keyring);
1068 /* instantiate the key and link it into a keyring */
1069 ret = key_instantiate_and_link(rka->target_key, payload, plen,
1070 dest_keyring, instkey);
1072 key_put(dest_keyring);
1074 /* discard the assumed authority if it's just been disabled by
1075 * instantiation of the key */
1077 keyctl_change_reqkey_auth(NULL);
1086 * Instantiate a key with the specified payload and link the key into the
1087 * destination keyring if one is given.
1089 * The caller must have the appropriate instantiation permit set for this to
1090 * work (see keyctl_assume_authority). No other permissions are required.
1092 * If successful, 0 will be returned.
1094 long keyctl_instantiate_key(key_serial_t id,
1095 const void __user *_payload,
1097 key_serial_t ringid)
1099 if (_payload && plen) {
1101 struct iov_iter from;
1104 ret = import_single_range(WRITE, (void __user *)_payload, plen,
1109 return keyctl_instantiate_key_common(id, &from, ringid);
1112 return keyctl_instantiate_key_common(id, NULL, ringid);
1116 * Instantiate a key with the specified multipart payload and link the key into
1117 * the destination keyring if one is given.
1119 * The caller must have the appropriate instantiation permit set for this to
1120 * work (see keyctl_assume_authority). No other permissions are required.
1122 * If successful, 0 will be returned.
1124 long keyctl_instantiate_key_iov(key_serial_t id,
1125 const struct iovec __user *_payload_iov,
1127 key_serial_t ringid)
1129 struct iovec iovstack[UIO_FASTIOV], *iov = iovstack;
1130 struct iov_iter from;
1136 ret = import_iovec(WRITE, _payload_iov, ioc,
1137 ARRAY_SIZE(iovstack), &iov, &from);
1140 ret = keyctl_instantiate_key_common(id, &from, ringid);
1146 * Negatively instantiate the key with the given timeout (in seconds) and link
1147 * the key into the destination keyring if one is given.
1149 * The caller must have the appropriate instantiation permit set for this to
1150 * work (see keyctl_assume_authority). No other permissions are required.
1152 * The key and any links to the key will be automatically garbage collected
1153 * after the timeout expires.
1155 * Negative keys are used to rate limit repeated request_key() calls by causing
1156 * them to return -ENOKEY until the negative key expires.
1158 * If successful, 0 will be returned.
1160 long keyctl_negate_key(key_serial_t id, unsigned timeout, key_serial_t ringid)
1162 return keyctl_reject_key(id, timeout, ENOKEY, ringid);
1166 * Negatively instantiate the key with the given timeout (in seconds) and error
1167 * code and link the key into the destination keyring if one is given.
1169 * The caller must have the appropriate instantiation permit set for this to
1170 * work (see keyctl_assume_authority). No other permissions are required.
1172 * The key and any links to the key will be automatically garbage collected
1173 * after the timeout expires.
1175 * Negative keys are used to rate limit repeated request_key() calls by causing
1176 * them to return the specified error code until the negative key expires.
1178 * If successful, 0 will be returned.
1180 long keyctl_reject_key(key_serial_t id, unsigned timeout, unsigned error,
1181 key_serial_t ringid)
1183 const struct cred *cred = current_cred();
1184 struct request_key_auth *rka;
1185 struct key *instkey, *dest_keyring;
1188 kenter("%d,%u,%u,%d", id, timeout, error, ringid);
1190 /* must be a valid error code and mustn't be a kernel special */
1192 error >= MAX_ERRNO ||
1193 error == ERESTARTSYS ||
1194 error == ERESTARTNOINTR ||
1195 error == ERESTARTNOHAND ||
1196 error == ERESTART_RESTARTBLOCK)
1199 /* the appropriate instantiation authorisation key must have been
1200 * assumed before calling this */
1202 instkey = cred->request_key_auth;
1206 rka = instkey->payload.data[0];
1207 if (rka->target_key->serial != id)
1210 /* find the destination keyring if present (which must also be
1212 ret = get_instantiation_keyring(ringid, rka, &dest_keyring);
1216 /* instantiate the key and link it into a keyring */
1217 ret = key_reject_and_link(rka->target_key, timeout, error,
1218 dest_keyring, instkey);
1220 key_put(dest_keyring);
1222 /* discard the assumed authority if it's just been disabled by
1223 * instantiation of the key */
1225 keyctl_change_reqkey_auth(NULL);
1232 * Read or set the default keyring in which request_key() will cache keys and
1233 * return the old setting.
1235 * If a thread or process keyring is specified then it will be created if it
1236 * doesn't yet exist. The old setting will be returned if successful.
1238 long keyctl_set_reqkey_keyring(int reqkey_defl)
1241 int ret, old_setting;
1243 old_setting = current_cred_xxx(jit_keyring);
1245 if (reqkey_defl == KEY_REQKEY_DEFL_NO_CHANGE)
1248 new = prepare_creds();
1252 switch (reqkey_defl) {
1253 case KEY_REQKEY_DEFL_THREAD_KEYRING:
1254 ret = install_thread_keyring_to_cred(new);
1259 case KEY_REQKEY_DEFL_PROCESS_KEYRING:
1260 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);