1 /* Userspace key control operations
3 * Copyright (C) 2004-5 Red Hat, Inc. All Rights Reserved.
4 * Written by David Howells (dhowells@redhat.com)
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public License
8 * as published by the Free Software Foundation; either version
9 * 2 of the License, or (at your option) any later version.
12 #include <linux/module.h>
13 #include <linux/init.h>
14 #include <linux/sched.h>
15 #include <linux/slab.h>
16 #include <linux/syscalls.h>
17 #include <linux/keyctl.h>
19 #include <linux/capability.h>
20 #include <linux/string.h>
21 #include <linux/err.h>
22 #include <linux/vmalloc.h>
23 #include <linux/security.h>
24 #include <asm/uaccess.h>
27 static int key_get_type_from_user(char *type,
28 const char __user *_type,
33 ret = strncpy_from_user(type, _type, len);
36 if (ret == 0 || ret >= len)
43 * Extract the description of a new key from userspace and either add it as a
44 * new key to the specified keyring or update a matching key in that keyring.
46 * The keyring must be writable so that we can attach the key to it.
48 * If successful, the new key's serial number is returned, otherwise an error
51 SYSCALL_DEFINE5(add_key, const char __user *, _type,
52 const char __user *, _description,
53 const void __user *, _payload,
57 key_ref_t keyring_ref, key_ref;
58 char type[32], *description;
64 if (plen > 1024 * 1024 - 1)
67 /* draw all the data into kernel space */
68 ret = key_get_type_from_user(type, _type, sizeof(type));
72 description = strndup_user(_description, PAGE_SIZE);
73 if (IS_ERR(description)) {
74 ret = PTR_ERR(description);
76 } else if ((description[0] == '.') &&
77 (strncmp(type, "keyring", 7) == 0)) {
82 /* pull the payload in if one was supplied */
88 payload = kmalloc(plen, GFP_KERNEL);
90 if (plen <= PAGE_SIZE)
93 payload = vmalloc(plen);
99 if (copy_from_user(payload, _payload, plen) != 0)
103 /* find the target keyring (which must be writable) */
104 keyring_ref = lookup_user_key(ringid, KEY_LOOKUP_CREATE, KEY_WRITE);
105 if (IS_ERR(keyring_ref)) {
106 ret = PTR_ERR(keyring_ref);
110 /* create or update the requested key and add it to the target
112 key_ref = key_create_or_update(keyring_ref, type, description,
113 payload, plen, KEY_PERM_UNDEF,
115 if (!IS_ERR(key_ref)) {
116 ret = key_ref_to_ptr(key_ref)->serial;
117 key_ref_put(key_ref);
120 ret = PTR_ERR(key_ref);
123 key_ref_put(keyring_ref);
136 * Search the process keyrings and keyring trees linked from those for a
137 * matching key. Keyrings must have appropriate Search permission to be
140 * If a key is found, it will be attached to the destination keyring if there's
141 * one specified and the serial number of the key will be returned.
143 * If no key is found, /sbin/request-key will be invoked if _callout_info is
144 * non-NULL in an attempt to create a key. The _callout_info string will be
145 * passed to /sbin/request-key to aid with completing the request. If the
146 * _callout_info string is "" then it will be changed to "-".
148 SYSCALL_DEFINE4(request_key, const char __user *, _type,
149 const char __user *, _description,
150 const char __user *, _callout_info,
151 key_serial_t, destringid)
153 struct key_type *ktype;
157 char type[32], *description, *callout_info;
160 /* pull the type into kernel space */
161 ret = key_get_type_from_user(type, _type, sizeof(type));
165 /* pull the description into kernel space */
166 description = strndup_user(_description, PAGE_SIZE);
167 if (IS_ERR(description)) {
168 ret = PTR_ERR(description);
172 /* pull the callout info into kernel space */
176 callout_info = strndup_user(_callout_info, PAGE_SIZE);
177 if (IS_ERR(callout_info)) {
178 ret = PTR_ERR(callout_info);
181 callout_len = strlen(callout_info);
184 /* get the destination keyring if specified */
187 dest_ref = lookup_user_key(destringid, KEY_LOOKUP_CREATE,
189 if (IS_ERR(dest_ref)) {
190 ret = PTR_ERR(dest_ref);
195 /* find the key type */
196 ktype = key_type_lookup(type);
198 ret = PTR_ERR(ktype);
203 key = request_key_and_link(ktype, description, callout_info,
204 callout_len, NULL, key_ref_to_ptr(dest_ref),
211 /* wait for the key to finish being constructed */
212 ret = wait_for_key_construction(key, 1);
223 key_ref_put(dest_ref);
233 * Get the ID of the specified process keyring.
235 * The requested keyring must have search permission to be found.
237 * If successful, the ID of the requested keyring will be returned.
239 long keyctl_get_keyring_ID(key_serial_t id, int create)
242 unsigned long lflags;
245 lflags = create ? KEY_LOOKUP_CREATE : 0;
246 key_ref = lookup_user_key(id, lflags, KEY_SEARCH);
247 if (IS_ERR(key_ref)) {
248 ret = PTR_ERR(key_ref);
252 ret = key_ref_to_ptr(key_ref)->serial;
253 key_ref_put(key_ref);
259 * Join a (named) session keyring.
261 * Create and join an anonymous session keyring or join a named session
262 * keyring, creating it if necessary. A named session keyring must have Search
263 * permission for it to be joined. Session keyrings without this permit will
266 * If successful, the ID of the joined session keyring will be returned.
268 long keyctl_join_session_keyring(const char __user *_name)
273 /* fetch the name from userspace */
276 name = strndup_user(_name, PAGE_SIZE);
283 /* join the session */
284 ret = join_session_keyring(name);
292 * Update a key's data payload from the given data.
294 * The key must grant the caller Write permission and the key type must support
295 * updating for this to work. A negative key can be positively instantiated
298 * If successful, 0 will be returned. If the key type does not support
299 * updating, then -EOPNOTSUPP will be returned.
301 long keyctl_update_key(key_serial_t id,
302 const void __user *_payload,
310 if (plen > PAGE_SIZE)
313 /* pull the payload in if one was supplied */
317 payload = kmalloc(plen, GFP_KERNEL);
322 if (copy_from_user(payload, _payload, plen) != 0)
326 /* find the target key (which must be writable) */
327 key_ref = lookup_user_key(id, 0, KEY_WRITE);
328 if (IS_ERR(key_ref)) {
329 ret = PTR_ERR(key_ref);
334 ret = key_update(key_ref, payload, plen);
336 key_ref_put(key_ref);
346 * The key must be grant the caller Write or Setattr permission for this to
347 * work. The key type should give up its quota claim when revoked. The key
348 * and any links to the key will be automatically garbage collected after a
349 * certain amount of time (/proc/sys/kernel/keys/gc_delay).
351 * If successful, 0 is returned.
353 long keyctl_revoke_key(key_serial_t id)
358 key_ref = lookup_user_key(id, 0, KEY_WRITE);
359 if (IS_ERR(key_ref)) {
360 ret = PTR_ERR(key_ref);
363 key_ref = lookup_user_key(id, 0, KEY_SETATTR);
364 if (IS_ERR(key_ref)) {
365 ret = PTR_ERR(key_ref);
370 key_revoke(key_ref_to_ptr(key_ref));
373 key_ref_put(key_ref);
379 * Clear the specified keyring, creating an empty process keyring if one of the
380 * special keyring IDs is used.
382 * The keyring must grant the caller Write permission for this to work. If
383 * successful, 0 will be returned.
385 long keyctl_keyring_clear(key_serial_t ringid)
387 key_ref_t keyring_ref;
390 keyring_ref = lookup_user_key(ringid, KEY_LOOKUP_CREATE, KEY_WRITE);
391 if (IS_ERR(keyring_ref)) {
392 ret = PTR_ERR(keyring_ref);
396 ret = keyring_clear(key_ref_to_ptr(keyring_ref));
398 key_ref_put(keyring_ref);
404 * Create a link from a keyring to a key if there's no matching key in the
405 * keyring, otherwise replace the link to the matching key with a link to the
408 * The key must grant the caller Link permission and the the keyring must grant
409 * the caller Write permission. Furthermore, if an additional link is created,
410 * the keyring's quota will be extended.
412 * If successful, 0 will be returned.
414 long keyctl_keyring_link(key_serial_t id, key_serial_t ringid)
416 key_ref_t keyring_ref, key_ref;
419 keyring_ref = lookup_user_key(ringid, KEY_LOOKUP_CREATE, KEY_WRITE);
420 if (IS_ERR(keyring_ref)) {
421 ret = PTR_ERR(keyring_ref);
425 key_ref = lookup_user_key(id, KEY_LOOKUP_CREATE, KEY_LINK);
426 if (IS_ERR(key_ref)) {
427 ret = PTR_ERR(key_ref);
431 ret = key_link(key_ref_to_ptr(keyring_ref), key_ref_to_ptr(key_ref));
433 key_ref_put(key_ref);
435 key_ref_put(keyring_ref);
441 * Unlink a key from a keyring.
443 * The keyring must grant the caller Write permission for this to work; the key
444 * itself need not grant the caller anything. If the last link to a key is
445 * removed then that key will be scheduled for destruction.
447 * If successful, 0 will be returned.
449 long keyctl_keyring_unlink(key_serial_t id, key_serial_t ringid)
451 key_ref_t keyring_ref, key_ref;
454 keyring_ref = lookup_user_key(ringid, 0, KEY_WRITE);
455 if (IS_ERR(keyring_ref)) {
456 ret = PTR_ERR(keyring_ref);
460 key_ref = lookup_user_key(id, KEY_LOOKUP_FOR_UNLINK, 0);
461 if (IS_ERR(key_ref)) {
462 ret = PTR_ERR(key_ref);
466 ret = key_unlink(key_ref_to_ptr(keyring_ref), key_ref_to_ptr(key_ref));
468 key_ref_put(key_ref);
470 key_ref_put(keyring_ref);
476 * Return a description of a key to userspace.
478 * The key must grant the caller View permission for this to work.
480 * If there's a buffer, we place up to buflen bytes of data into it formatted
481 * in the following way:
483 * type;uid;gid;perm;description<NUL>
485 * If successful, we return the amount of description available, irrespective
486 * of how much we may have copied into the buffer.
488 long keyctl_describe_key(key_serial_t keyid,
492 struct key *key, *instkey;
497 key_ref = lookup_user_key(keyid, KEY_LOOKUP_PARTIAL, KEY_VIEW);
498 if (IS_ERR(key_ref)) {
499 /* viewing a key under construction is permitted if we have the
500 * authorisation token handy */
501 if (PTR_ERR(key_ref) == -EACCES) {
502 instkey = key_get_instantiation_authkey(keyid);
503 if (!IS_ERR(instkey)) {
505 key_ref = lookup_user_key(keyid,
508 if (!IS_ERR(key_ref))
513 ret = PTR_ERR(key_ref);
518 /* calculate how much description we're going to return */
520 tmpbuf = kmalloc(PAGE_SIZE, GFP_KERNEL);
524 key = key_ref_to_ptr(key_ref);
526 ret = snprintf(tmpbuf, PAGE_SIZE - 1,
532 key->description ?: "");
534 /* include a NUL char at the end of the data */
535 if (ret > PAGE_SIZE - 1)
540 /* consider returning the data */
541 if (buffer && buflen > 0) {
545 if (copy_to_user(buffer, tmpbuf, buflen) != 0)
551 key_ref_put(key_ref);
557 * Search the specified keyring and any keyrings it links to for a matching
558 * key. Only keyrings that grant the caller Search permission will be searched
559 * (this includes the starting keyring). Only keys with Search permission can
562 * If successful, the found key will be linked to the destination keyring if
563 * supplied and the key has Link permission, and the found key ID will be
566 long keyctl_keyring_search(key_serial_t ringid,
567 const char __user *_type,
568 const char __user *_description,
569 key_serial_t destringid)
571 struct key_type *ktype;
572 key_ref_t keyring_ref, key_ref, dest_ref;
573 char type[32], *description;
576 /* pull the type and description into kernel space */
577 ret = key_get_type_from_user(type, _type, sizeof(type));
581 description = strndup_user(_description, PAGE_SIZE);
582 if (IS_ERR(description)) {
583 ret = PTR_ERR(description);
587 /* get the keyring at which to begin the search */
588 keyring_ref = lookup_user_key(ringid, 0, KEY_SEARCH);
589 if (IS_ERR(keyring_ref)) {
590 ret = PTR_ERR(keyring_ref);
594 /* get the destination keyring if specified */
597 dest_ref = lookup_user_key(destringid, KEY_LOOKUP_CREATE,
599 if (IS_ERR(dest_ref)) {
600 ret = PTR_ERR(dest_ref);
605 /* find the key type */
606 ktype = key_type_lookup(type);
608 ret = PTR_ERR(ktype);
613 key_ref = keyring_search(keyring_ref, ktype, description);
614 if (IS_ERR(key_ref)) {
615 ret = PTR_ERR(key_ref);
617 /* treat lack or presence of a negative key the same */
623 /* link the resulting key to the destination keyring if we can */
625 ret = key_permission(key_ref, KEY_LINK);
629 ret = key_link(key_ref_to_ptr(dest_ref), key_ref_to_ptr(key_ref));
634 ret = key_ref_to_ptr(key_ref)->serial;
637 key_ref_put(key_ref);
641 key_ref_put(dest_ref);
643 key_ref_put(keyring_ref);
651 * Read a key's payload.
653 * The key must either grant the caller Read permission, or it must grant the
654 * caller Search permission when searched for from the process keyrings.
656 * If successful, we place up to buflen bytes of data into the buffer, if one
657 * is provided, and return the amount of data that is available in the key,
658 * irrespective of how much we copied into the buffer.
660 long keyctl_read_key(key_serial_t keyid, char __user *buffer, size_t buflen)
666 /* find the key first */
667 key_ref = lookup_user_key(keyid, 0, 0);
668 if (IS_ERR(key_ref)) {
673 key = key_ref_to_ptr(key_ref);
675 /* see if we can read it directly */
676 ret = key_permission(key_ref, KEY_READ);
682 /* we can't; see if it's searchable from this process's keyrings
683 * - we automatically take account of the fact that it may be
684 * dangling off an instantiation key
686 if (!is_key_possessed(key_ref)) {
691 /* the key is probably readable - now try to read it */
694 if (key->type->read) {
695 /* Read the data with the semaphore held (since we might sleep)
696 * to protect against the key being updated or revoked.
698 down_read(&key->sem);
699 ret = key_validate(key);
701 ret = key->type->read(key, buffer, buflen);
712 * Change the ownership of a key
714 * The key must grant the caller Setattr permission for this to work, though
715 * the key need not be fully instantiated yet. For the UID to be changed, or
716 * for the GID to be changed to a group the caller is not a member of, the
717 * caller must have sysadmin capability. If either uid or gid is -1 then that
718 * attribute is not changed.
720 * If the UID is to be changed, the new user must have sufficient quota to
721 * accept the key. The quota deduction will be removed from the old user to
722 * the new user should the attribute be changed.
724 * If successful, 0 will be returned.
726 long keyctl_chown_key(key_serial_t id, uid_t uid, gid_t gid)
728 struct key_user *newowner, *zapowner = NULL;
734 if (uid == (uid_t) -1 && gid == (gid_t) -1)
737 key_ref = lookup_user_key(id, KEY_LOOKUP_CREATE | KEY_LOOKUP_PARTIAL,
739 if (IS_ERR(key_ref)) {
740 ret = PTR_ERR(key_ref);
744 key = key_ref_to_ptr(key_ref);
746 /* make the changes with the locks held to prevent chown/chown races */
748 down_write(&key->sem);
750 if (!capable(CAP_SYS_ADMIN)) {
751 /* only the sysadmin can chown a key to some other UID */
752 if (uid != (uid_t) -1 && key->uid != uid)
755 /* only the sysadmin can set the key's GID to a group other
756 * than one of those that the current process subscribes to */
757 if (gid != (gid_t) -1 && gid != key->gid && !in_group_p(gid))
762 if (uid != (uid_t) -1 && uid != key->uid) {
764 newowner = key_user_lookup(uid, current_user_ns());
768 /* transfer the quota burden to the new user */
769 if (test_bit(KEY_FLAG_IN_QUOTA, &key->flags)) {
770 unsigned maxkeys = (uid == 0) ?
771 key_quota_root_maxkeys : key_quota_maxkeys;
772 unsigned maxbytes = (uid == 0) ?
773 key_quota_root_maxbytes : key_quota_maxbytes;
775 spin_lock(&newowner->lock);
776 if (newowner->qnkeys + 1 >= maxkeys ||
777 newowner->qnbytes + key->quotalen >= maxbytes ||
778 newowner->qnbytes + key->quotalen <
783 newowner->qnbytes += key->quotalen;
784 spin_unlock(&newowner->lock);
786 spin_lock(&key->user->lock);
788 key->user->qnbytes -= key->quotalen;
789 spin_unlock(&key->user->lock);
792 atomic_dec(&key->user->nkeys);
793 atomic_inc(&newowner->nkeys);
795 if (test_bit(KEY_FLAG_INSTANTIATED, &key->flags)) {
796 atomic_dec(&key->user->nikeys);
797 atomic_inc(&newowner->nikeys);
800 zapowner = key->user;
801 key->user = newowner;
806 if (gid != (gid_t) -1)
815 key_user_put(zapowner);
820 spin_unlock(&newowner->lock);
827 * Change the permission mask on a key.
829 * The key must grant the caller Setattr permission for this to work, though
830 * the key need not be fully instantiated yet. If the caller does not have
831 * sysadmin capability, it may only change the permission on keys that it owns.
833 long keyctl_setperm_key(key_serial_t id, key_perm_t perm)
840 if (perm & ~(KEY_POS_ALL | KEY_USR_ALL | KEY_GRP_ALL | KEY_OTH_ALL))
843 key_ref = lookup_user_key(id, KEY_LOOKUP_CREATE | KEY_LOOKUP_PARTIAL,
845 if (IS_ERR(key_ref)) {
846 ret = PTR_ERR(key_ref);
850 key = key_ref_to_ptr(key_ref);
852 /* make the changes with the locks held to prevent chown/chmod races */
854 down_write(&key->sem);
856 /* if we're not the sysadmin, we can only change a key that we own */
857 if (capable(CAP_SYS_ADMIN) || key->uid == current_fsuid()) {
869 * Get the destination keyring for instantiation and check that the caller has
870 * Write permission on it.
872 static long get_instantiation_keyring(key_serial_t ringid,
873 struct request_key_auth *rka,
874 struct key **_dest_keyring)
878 *_dest_keyring = NULL;
880 /* just return a NULL pointer if we weren't asked to make a link */
884 /* if a specific keyring is nominated by ID, then use that */
886 dkref = lookup_user_key(ringid, KEY_LOOKUP_CREATE, KEY_WRITE);
888 return PTR_ERR(dkref);
889 *_dest_keyring = key_ref_to_ptr(dkref);
893 if (ringid == KEY_SPEC_REQKEY_AUTH_KEY)
896 /* otherwise specify the destination keyring recorded in the
897 * authorisation key (any KEY_SPEC_*_KEYRING) */
898 if (ringid >= KEY_SPEC_REQUESTOR_KEYRING) {
899 *_dest_keyring = key_get(rka->dest_keyring);
907 * Change the request_key authorisation key on the current process.
909 static int keyctl_change_reqkey_auth(struct key *key)
913 new = prepare_creds();
917 key_put(new->request_key_auth);
918 new->request_key_auth = key_get(key);
920 return commit_creds(new);
924 * Copy the iovec data from userspace
926 static long copy_from_user_iovec(void *buffer, const struct iovec *iov,
929 for (; ioc > 0; ioc--) {
930 if (copy_from_user(buffer, iov->iov_base, iov->iov_len) != 0)
932 buffer += iov->iov_len;
939 * Instantiate a key with the specified payload and link the key into the
940 * destination keyring if one is given.
942 * The caller must have the appropriate instantiation permit set for this to
943 * work (see keyctl_assume_authority). No other permissions are required.
945 * If successful, 0 will be returned.
947 long keyctl_instantiate_key_common(key_serial_t id,
948 const struct iovec *payload_iov,
953 const struct cred *cred = current_cred();
954 struct request_key_auth *rka;
955 struct key *instkey, *dest_keyring;
960 kenter("%d,,%zu,%d", id, plen, ringid);
963 if (plen > 1024 * 1024 - 1)
966 /* the appropriate instantiation authorisation key must have been
967 * assumed before calling this */
969 instkey = cred->request_key_auth;
973 rka = instkey->payload.data;
974 if (rka->target_key->serial != id)
977 /* pull the payload in if one was supplied */
982 payload = kmalloc(plen, GFP_KERNEL);
984 if (plen <= PAGE_SIZE)
987 payload = vmalloc(plen);
992 ret = copy_from_user_iovec(payload, payload_iov, ioc);
997 /* find the destination keyring amongst those belonging to the
999 ret = get_instantiation_keyring(ringid, rka, &dest_keyring);
1003 /* instantiate the key and link it into a keyring */
1004 ret = key_instantiate_and_link(rka->target_key, payload, plen,
1005 dest_keyring, instkey);
1007 key_put(dest_keyring);
1009 /* discard the assumed authority if it's just been disabled by
1010 * instantiation of the key */
1012 keyctl_change_reqkey_auth(NULL);
1024 * Instantiate a key with the specified payload and link the key into the
1025 * destination keyring if one is given.
1027 * The caller must have the appropriate instantiation permit set for this to
1028 * work (see keyctl_assume_authority). No other permissions are required.
1030 * If successful, 0 will be returned.
1032 long keyctl_instantiate_key(key_serial_t id,
1033 const void __user *_payload,
1035 key_serial_t ringid)
1037 if (_payload && plen) {
1038 struct iovec iov[1] = {
1039 [0].iov_base = (void __user *)_payload,
1043 return keyctl_instantiate_key_common(id, iov, 1, plen, ringid);
1046 return keyctl_instantiate_key_common(id, NULL, 0, 0, ringid);
1050 * Instantiate a key with the specified multipart payload and link the key into
1051 * the destination keyring if one is given.
1053 * The caller must have the appropriate instantiation permit set for this to
1054 * work (see keyctl_assume_authority). No other permissions are required.
1056 * If successful, 0 will be returned.
1058 long keyctl_instantiate_key_iov(key_serial_t id,
1059 const struct iovec __user *_payload_iov,
1061 key_serial_t ringid)
1063 struct iovec iovstack[UIO_FASTIOV], *iov = iovstack;
1066 if (_payload_iov == 0 || ioc == 0)
1069 ret = rw_copy_check_uvector(WRITE, _payload_iov, ioc,
1070 ARRAY_SIZE(iovstack), iovstack, &iov, 1);
1074 goto no_payload_free;
1076 ret = keyctl_instantiate_key_common(id, iov, ioc, ret, ringid);
1078 if (iov != iovstack)
1083 if (iov != iovstack)
1086 return keyctl_instantiate_key_common(id, NULL, 0, 0, ringid);
1090 * Negatively instantiate the key with the given timeout (in seconds) and link
1091 * the key into the destination keyring if one is given.
1093 * The caller must have the appropriate instantiation permit set for this to
1094 * work (see keyctl_assume_authority). No other permissions are required.
1096 * The key and any links to the key will be automatically garbage collected
1097 * after the timeout expires.
1099 * Negative keys are used to rate limit repeated request_key() calls by causing
1100 * them to return -ENOKEY until the negative key expires.
1102 * If successful, 0 will be returned.
1104 long keyctl_negate_key(key_serial_t id, unsigned timeout, key_serial_t ringid)
1106 return keyctl_reject_key(id, timeout, ENOKEY, ringid);
1110 * Negatively instantiate the key with the given timeout (in seconds) and error
1111 * code and link the key into the destination keyring if one is given.
1113 * The caller must have the appropriate instantiation permit set for this to
1114 * work (see keyctl_assume_authority). No other permissions are required.
1116 * The key and any links to the key will be automatically garbage collected
1117 * after the timeout expires.
1119 * Negative keys are used to rate limit repeated request_key() calls by causing
1120 * them to return the specified error code until the negative key expires.
1122 * If successful, 0 will be returned.
1124 long keyctl_reject_key(key_serial_t id, unsigned timeout, unsigned error,
1125 key_serial_t ringid)
1127 const struct cred *cred = current_cred();
1128 struct request_key_auth *rka;
1129 struct key *instkey, *dest_keyring;
1132 kenter("%d,%u,%u,%d", id, timeout, error, ringid);
1134 /* must be a valid error code and mustn't be a kernel special */
1136 error >= MAX_ERRNO ||
1137 error == ERESTARTSYS ||
1138 error == ERESTARTNOINTR ||
1139 error == ERESTARTNOHAND ||
1140 error == ERESTART_RESTARTBLOCK)
1143 /* the appropriate instantiation authorisation key must have been
1144 * assumed before calling this */
1146 instkey = cred->request_key_auth;
1150 rka = instkey->payload.data;
1151 if (rka->target_key->serial != id)
1154 /* find the destination keyring if present (which must also be
1156 ret = get_instantiation_keyring(ringid, rka, &dest_keyring);
1160 /* instantiate the key and link it into a keyring */
1161 ret = key_reject_and_link(rka->target_key, timeout, error,
1162 dest_keyring, instkey);
1164 key_put(dest_keyring);
1166 /* discard the assumed authority if it's just been disabled by
1167 * instantiation of the key */
1169 keyctl_change_reqkey_auth(NULL);
1176 * Read or set the default keyring in which request_key() will cache keys and
1177 * return the old setting.
1179 * If a process keyring is specified then this will be created if it doesn't
1180 * yet exist. The old setting will be returned if successful.
1182 long keyctl_set_reqkey_keyring(int reqkey_defl)
1185 int ret, old_setting;
1187 old_setting = current_cred_xxx(jit_keyring);
1189 if (reqkey_defl == KEY_REQKEY_DEFL_NO_CHANGE)
1192 new = prepare_creds();
1196 switch (reqkey_defl) {
1197 case KEY_REQKEY_DEFL_THREAD_KEYRING:
1198 ret = install_thread_keyring_to_cred(new);
1203 case KEY_REQKEY_DEFL_PROCESS_KEYRING:
1204 ret = install_process_keyring_to_cred(new);
1212 case KEY_REQKEY_DEFL_DEFAULT:
1213 case KEY_REQKEY_DEFL_SESSION_KEYRING:
1214 case KEY_REQKEY_DEFL_USER_KEYRING:
1215 case KEY_REQKEY_DEFL_USER_SESSION_KEYRING:
1216 case KEY_REQKEY_DEFL_REQUESTOR_KEYRING:
1219 case KEY_REQKEY_DEFL_NO_CHANGE:
1220 case KEY_REQKEY_DEFL_GROUP_KEYRING:
1227 new->jit_keyring = reqkey_defl;
1236 * Set or clear the timeout on a key.
1238 * Either the key must grant the caller Setattr permission or else the caller
1239 * must hold an instantiation authorisation token for the key.
1241 * The timeout is either 0 to clear the timeout, or a number of seconds from
1242 * the current time. The key and any links to the key will be automatically
1243 * garbage collected after the timeout expires.
1245 * If successful, 0 is returned.
1247 long keyctl_set_timeout(key_serial_t id, unsigned timeout)
1249 struct timespec now;
1250 struct key *key, *instkey;
1255 key_ref = lookup_user_key(id, KEY_LOOKUP_CREATE | KEY_LOOKUP_PARTIAL,
1257 if (IS_ERR(key_ref)) {
1258 /* setting the timeout on a key under construction is permitted
1259 * if we have the authorisation token handy */
1260 if (PTR_ERR(key_ref) == -EACCES) {
1261 instkey = key_get_instantiation_authkey(id);
1262 if (!IS_ERR(instkey)) {
1264 key_ref = lookup_user_key(id,
1267 if (!IS_ERR(key_ref))
1272 ret = PTR_ERR(key_ref);
1277 key = key_ref_to_ptr(key_ref);
1279 /* make the changes with the locks held to prevent races */
1280 down_write(&key->sem);
1284 now = current_kernel_time();
1285 expiry = now.tv_sec + timeout;
1288 key->expiry = expiry;
1289 key_schedule_gc(key->expiry + key_gc_delay);
1291 up_write(&key->sem);
1300 * Assume (or clear) the authority to instantiate the specified key.
1302 * This sets the authoritative token currently in force for key instantiation.
1303 * This must be done for a key to be instantiated. It has the effect of making
1304 * available all the keys from the caller of the request_key() that created a
1305 * key to request_key() calls made by the caller of this function.
1307 * The caller must have the instantiation key in their process keyrings with a
1308 * Search permission grant available to the caller.
1310 * If the ID given is 0, then the setting will be cleared and 0 returned.
1312 * If the ID given has a matching an authorisation key, then that key will be
1313 * set and its ID will be returned. The authorisation key can be read to get
1314 * the callout information passed to request_key().
1316 long keyctl_assume_authority(key_serial_t id)
1318 struct key *authkey;
1321 /* special key IDs aren't permitted */
1326 /* we divest ourselves of authority if given an ID of 0 */
1328 ret = keyctl_change_reqkey_auth(NULL);
1332 /* attempt to assume the authority temporarily granted to us whilst we
1333 * instantiate the specified key
1334 * - the authorisation key must be in the current task's keyrings
1337 authkey = key_get_instantiation_authkey(id);
1338 if (IS_ERR(authkey)) {
1339 ret = PTR_ERR(authkey);
1343 ret = keyctl_change_reqkey_auth(authkey);
1348 ret = authkey->serial;
1354 * Get a key's the LSM security label.
1356 * The key must grant the caller View permission for this to work.
1358 * If there's a buffer, then up to buflen bytes of data will be placed into it.
1360 * If successful, the amount of information available will be returned,
1361 * irrespective of how much was copied (including the terminal NUL).
1363 long keyctl_get_security(key_serial_t keyid,
1364 char __user *buffer,
1367 struct key *key, *instkey;
1372 key_ref = lookup_user_key(keyid, KEY_LOOKUP_PARTIAL, KEY_VIEW);
1373 if (IS_ERR(key_ref)) {
1374 if (PTR_ERR(key_ref) != -EACCES)
1375 return PTR_ERR(key_ref);
1377 /* viewing a key under construction is also permitted if we
1378 * have the authorisation token handy */
1379 instkey = key_get_instantiation_authkey(keyid);
1380 if (IS_ERR(instkey))
1381 return PTR_ERR(instkey);
1384 key_ref = lookup_user_key(keyid, KEY_LOOKUP_PARTIAL, 0);
1385 if (IS_ERR(key_ref))
1386 return PTR_ERR(key_ref);
1389 key = key_ref_to_ptr(key_ref);
1390 ret = security_key_getsecurity(key, &context);
1392 /* if no information was returned, give userspace an empty
1395 if (buffer && buflen > 0 &&
1396 copy_to_user(buffer, "", 1) != 0)
1398 } else if (ret > 0) {
1399 /* return as much data as there's room for */
1400 if (buffer && buflen > 0) {
1404 if (copy_to_user(buffer, context, buflen) != 0)
1411 key_ref_put(key_ref);
1416 * Attempt to install the calling process's session keyring on the process's
1419 * The keyring must exist and must grant the caller LINK permission, and the
1420 * parent process must be single-threaded and must have the same effective
1421 * ownership as this process and mustn't be SUID/SGID.
1423 * The keyring will be emplaced on the parent when it next resumes userspace.
1425 * If successful, 0 will be returned.
1427 long keyctl_session_to_parent(void)
1429 #ifdef TIF_NOTIFY_RESUME
1430 struct task_struct *me, *parent;
1431 const struct cred *mycred, *pcred;
1432 struct cred *cred, *oldcred;
1433 key_ref_t keyring_r;
1436 keyring_r = lookup_user_key(KEY_SPEC_SESSION_KEYRING, 0, KEY_LINK);
1437 if (IS_ERR(keyring_r))
1438 return PTR_ERR(keyring_r);
1440 /* our parent is going to need a new cred struct, a new tgcred struct
1441 * and new security data, so we allocate them here to prevent ENOMEM in
1444 cred = cred_alloc_blank();
1448 cred->tgcred->session_keyring = key_ref_to_ptr(keyring_r);
1453 write_lock_irq(&tasklist_lock);
1455 parent = me->real_parent;
1458 /* the parent mustn't be init and mustn't be a kernel thread */
1459 if (parent->pid <= 1 || !parent->mm)
1462 /* the parent must be single threaded */
1463 if (!thread_group_empty(parent))
1466 /* the parent and the child must have different session keyrings or
1467 * there's no point */
1468 mycred = current_cred();
1469 pcred = __task_cred(parent);
1470 if (mycred == pcred ||
1471 mycred->tgcred->session_keyring == pcred->tgcred->session_keyring)
1474 /* the parent must have the same effective ownership and mustn't be
1476 if (pcred->uid != mycred->euid ||
1477 pcred->euid != mycred->euid ||
1478 pcred->suid != mycred->euid ||
1479 pcred->gid != mycred->egid ||
1480 pcred->egid != mycred->egid ||
1481 pcred->sgid != mycred->egid)
1484 /* the keyrings must have the same UID */
1485 if ((pcred->tgcred->session_keyring &&
1486 pcred->tgcred->session_keyring->uid != mycred->euid) ||
1487 mycred->tgcred->session_keyring->uid != mycred->euid)
1490 /* if there's an already pending keyring replacement, then we replace
1492 oldcred = parent->replacement_session_keyring;
1494 /* the replacement session keyring is applied just prior to userspace
1496 parent->replacement_session_keyring = cred;
1498 set_ti_thread_flag(task_thread_info(parent), TIF_NOTIFY_RESUME);
1500 write_unlock_irq(&tasklist_lock);
1509 write_unlock_irq(&tasklist_lock);
1515 key_ref_put(keyring_r);
1518 #else /* !TIF_NOTIFY_RESUME */
1520 * To be removed when TIF_NOTIFY_RESUME has been implemented on
1523 #warning TIF_NOTIFY_RESUME not implemented
1525 #endif /* !TIF_NOTIFY_RESUME */
1529 * The key control system call
1531 SYSCALL_DEFINE5(keyctl, int, option, unsigned long, arg2, unsigned long, arg3,
1532 unsigned long, arg4, unsigned long, arg5)
1535 case KEYCTL_GET_KEYRING_ID:
1536 return keyctl_get_keyring_ID((key_serial_t) arg2,
1539 case KEYCTL_JOIN_SESSION_KEYRING:
1540 return keyctl_join_session_keyring((const char __user *) arg2);
1543 return keyctl_update_key((key_serial_t) arg2,
1544 (const void __user *) arg3,
1548 return keyctl_revoke_key((key_serial_t) arg2);
1550 case KEYCTL_DESCRIBE:
1551 return keyctl_describe_key((key_serial_t) arg2,
1552 (char __user *) arg3,
1556 return keyctl_keyring_clear((key_serial_t) arg2);
1559 return keyctl_keyring_link((key_serial_t) arg2,
1560 (key_serial_t) arg3);
1563 return keyctl_keyring_unlink((key_serial_t) arg2,
1564 (key_serial_t) arg3);
1567 return keyctl_keyring_search((key_serial_t) arg2,
1568 (const char __user *) arg3,
1569 (const char __user *) arg4,
1570 (key_serial_t) arg5);
1573 return keyctl_read_key((key_serial_t) arg2,
1574 (char __user *) arg3,
1578 return keyctl_chown_key((key_serial_t) arg2,
1582 case KEYCTL_SETPERM:
1583 return keyctl_setperm_key((key_serial_t) arg2,
1586 case KEYCTL_INSTANTIATE:
1587 return keyctl_instantiate_key((key_serial_t) arg2,
1588 (const void __user *) arg3,
1590 (key_serial_t) arg5);
1593 return keyctl_negate_key((key_serial_t) arg2,
1595 (key_serial_t) arg4);
1597 case KEYCTL_SET_REQKEY_KEYRING:
1598 return keyctl_set_reqkey_keyring(arg2);
1600 case KEYCTL_SET_TIMEOUT:
1601 return keyctl_set_timeout((key_serial_t) arg2,
1604 case KEYCTL_ASSUME_AUTHORITY:
1605 return keyctl_assume_authority((key_serial_t) arg2);
1607 case KEYCTL_GET_SECURITY:
1608 return keyctl_get_security((key_serial_t) arg2,
1609 (char __user *) arg3,
1612 case KEYCTL_SESSION_TO_PARENT:
1613 return keyctl_session_to_parent();
1616 return keyctl_reject_key((key_serial_t) arg2,
1619 (key_serial_t) arg5);
1621 case KEYCTL_INSTANTIATE_IOV:
1622 return keyctl_instantiate_key_iov(
1623 (key_serial_t) arg2,
1624 (const struct iovec __user *) arg3,
1626 (key_serial_t) arg5);