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 <asm/uaccess.h>
28 static int key_get_type_from_user(char *type,
29 const char __user *_type,
34 ret = strncpy_from_user(type, _type, len);
37 if (ret == 0 || ret >= len)
46 * Extract the description of a new key from userspace and either add it as a
47 * new key to the specified keyring or update a matching key in that keyring.
49 * The keyring must be writable so that we can attach the key to it.
51 * If successful, the new key's serial number is returned, otherwise an error
54 SYSCALL_DEFINE5(add_key, const char __user *, _type,
55 const char __user *, _description,
56 const void __user *, _payload,
60 key_ref_t keyring_ref, key_ref;
61 char type[32], *description;
67 if (plen > 1024 * 1024 - 1)
70 /* draw all the data into kernel space */
71 ret = key_get_type_from_user(type, _type, sizeof(type));
75 description = strndup_user(_description, PAGE_SIZE);
76 if (IS_ERR(description)) {
77 ret = PTR_ERR(description);
81 /* pull the payload in if one was supplied */
87 payload = kmalloc(plen, GFP_KERNEL);
89 if (plen <= PAGE_SIZE)
92 payload = vmalloc(plen);
98 if (copy_from_user(payload, _payload, plen) != 0)
102 /* find the target keyring (which must be writable) */
103 keyring_ref = lookup_user_key(ringid, KEY_LOOKUP_CREATE, KEY_WRITE);
104 if (IS_ERR(keyring_ref)) {
105 ret = PTR_ERR(keyring_ref);
109 /* create or update the requested key and add it to the target
111 key_ref = key_create_or_update(keyring_ref, type, description,
112 payload, plen, KEY_PERM_UNDEF,
114 if (!IS_ERR(key_ref)) {
115 ret = key_ref_to_ptr(key_ref)->serial;
116 key_ref_put(key_ref);
119 ret = PTR_ERR(key_ref);
122 key_ref_put(keyring_ref);
135 * Search the process keyrings and keyring trees linked from those for a
136 * matching key. Keyrings must have appropriate Search permission to be
139 * If a key is found, it will be attached to the destination keyring if there's
140 * one specified and the serial number of the key will be returned.
142 * If no key is found, /sbin/request-key will be invoked if _callout_info is
143 * non-NULL in an attempt to create a key. The _callout_info string will be
144 * passed to /sbin/request-key to aid with completing the request. If the
145 * _callout_info string is "" then it will be changed to "-".
147 SYSCALL_DEFINE4(request_key, const char __user *, _type,
148 const char __user *, _description,
149 const char __user *, _callout_info,
150 key_serial_t, destringid)
152 struct key_type *ktype;
156 char type[32], *description, *callout_info;
159 /* pull the type into kernel space */
160 ret = key_get_type_from_user(type, _type, sizeof(type));
164 /* pull the description into kernel space */
165 description = strndup_user(_description, PAGE_SIZE);
166 if (IS_ERR(description)) {
167 ret = PTR_ERR(description);
171 /* pull the callout info into kernel space */
175 callout_info = strndup_user(_callout_info, PAGE_SIZE);
176 if (IS_ERR(callout_info)) {
177 ret = PTR_ERR(callout_info);
180 callout_len = strlen(callout_info);
183 /* get the destination keyring if specified */
186 dest_ref = lookup_user_key(destringid, KEY_LOOKUP_CREATE,
188 if (IS_ERR(dest_ref)) {
189 ret = PTR_ERR(dest_ref);
194 /* find the key type */
195 ktype = key_type_lookup(type);
197 ret = PTR_ERR(ktype);
202 key = request_key_and_link(ktype, description, callout_info,
203 callout_len, NULL, key_ref_to_ptr(dest_ref),
210 /* wait for the key to finish being constructed */
211 ret = wait_for_key_construction(key, 1);
222 key_ref_put(dest_ref);
232 * Get the ID of the specified process keyring.
234 * The requested keyring must have search permission to be found.
236 * If successful, the ID of the requested keyring will be returned.
238 long keyctl_get_keyring_ID(key_serial_t id, int create)
241 unsigned long lflags;
244 lflags = create ? KEY_LOOKUP_CREATE : 0;
245 key_ref = lookup_user_key(id, lflags, KEY_SEARCH);
246 if (IS_ERR(key_ref)) {
247 ret = PTR_ERR(key_ref);
251 ret = key_ref_to_ptr(key_ref)->serial;
252 key_ref_put(key_ref);
258 * Join a (named) session keyring.
260 * Create and join an anonymous session keyring or join a named session
261 * keyring, creating it if necessary. A named session keyring must have Search
262 * permission for it to be joined. Session keyrings without this permit will
265 * If successful, the ID of the joined session keyring will be returned.
267 long keyctl_join_session_keyring(const char __user *_name)
272 /* fetch the name from userspace */
275 name = strndup_user(_name, PAGE_SIZE);
282 /* join the session */
283 ret = join_session_keyring(name);
291 * Update a key's data payload from the given data.
293 * The key must grant the caller Write permission and the key type must support
294 * updating for this to work. A negative key can be positively instantiated
297 * If successful, 0 will be returned. If the key type does not support
298 * updating, then -EOPNOTSUPP will be returned.
300 long keyctl_update_key(key_serial_t id,
301 const void __user *_payload,
309 if (plen > PAGE_SIZE)
312 /* pull the payload in if one was supplied */
316 payload = kmalloc(plen, GFP_KERNEL);
321 if (copy_from_user(payload, _payload, plen) != 0)
325 /* find the target key (which must be writable) */
326 key_ref = lookup_user_key(id, 0, KEY_WRITE);
327 if (IS_ERR(key_ref)) {
328 ret = PTR_ERR(key_ref);
333 ret = key_update(key_ref, payload, plen);
335 key_ref_put(key_ref);
345 * The key must be grant the caller Write or Setattr permission for this to
346 * work. The key type should give up its quota claim when revoked. The key
347 * and any links to the key will be automatically garbage collected after a
348 * certain amount of time (/proc/sys/kernel/keys/gc_delay).
350 * If successful, 0 is returned.
352 long keyctl_revoke_key(key_serial_t id)
357 key_ref = lookup_user_key(id, 0, KEY_WRITE);
358 if (IS_ERR(key_ref)) {
359 ret = PTR_ERR(key_ref);
362 key_ref = lookup_user_key(id, 0, KEY_SETATTR);
363 if (IS_ERR(key_ref)) {
364 ret = PTR_ERR(key_ref);
369 key_revoke(key_ref_to_ptr(key_ref));
372 key_ref_put(key_ref);
378 * Clear the specified keyring, creating an empty process keyring if one of the
379 * special keyring IDs is used.
381 * The keyring must grant the caller Write permission for this to work. If
382 * successful, 0 will be returned.
384 long keyctl_keyring_clear(key_serial_t ringid)
386 key_ref_t keyring_ref;
389 keyring_ref = lookup_user_key(ringid, KEY_LOOKUP_CREATE, KEY_WRITE);
390 if (IS_ERR(keyring_ref)) {
391 ret = PTR_ERR(keyring_ref);
393 /* Root is permitted to invalidate certain special keyrings */
394 if (capable(CAP_SYS_ADMIN)) {
395 keyring_ref = lookup_user_key(ringid, 0, 0);
396 if (IS_ERR(keyring_ref))
398 if (test_bit(KEY_FLAG_ROOT_CAN_CLEAR,
399 &key_ref_to_ptr(keyring_ref)->flags))
408 ret = keyring_clear(key_ref_to_ptr(keyring_ref));
410 key_ref_put(keyring_ref);
416 * Create a link from a keyring to a key if there's no matching key in the
417 * keyring, otherwise replace the link to the matching key with a link to the
420 * The key must grant the caller Link permission and the the keyring must grant
421 * the caller Write permission. Furthermore, if an additional link is created,
422 * the keyring's quota will be extended.
424 * If successful, 0 will be returned.
426 long keyctl_keyring_link(key_serial_t id, key_serial_t ringid)
428 key_ref_t keyring_ref, key_ref;
431 keyring_ref = lookup_user_key(ringid, KEY_LOOKUP_CREATE, KEY_WRITE);
432 if (IS_ERR(keyring_ref)) {
433 ret = PTR_ERR(keyring_ref);
437 key_ref = lookup_user_key(id, KEY_LOOKUP_CREATE, KEY_LINK);
438 if (IS_ERR(key_ref)) {
439 ret = PTR_ERR(key_ref);
443 ret = key_link(key_ref_to_ptr(keyring_ref), key_ref_to_ptr(key_ref));
445 key_ref_put(key_ref);
447 key_ref_put(keyring_ref);
453 * Unlink a key from a keyring.
455 * The keyring must grant the caller Write permission for this to work; the key
456 * itself need not grant the caller anything. If the last link to a key is
457 * removed then that key will be scheduled for destruction.
459 * If successful, 0 will be returned.
461 long keyctl_keyring_unlink(key_serial_t id, key_serial_t ringid)
463 key_ref_t keyring_ref, key_ref;
466 keyring_ref = lookup_user_key(ringid, 0, KEY_WRITE);
467 if (IS_ERR(keyring_ref)) {
468 ret = PTR_ERR(keyring_ref);
472 key_ref = lookup_user_key(id, KEY_LOOKUP_FOR_UNLINK, 0);
473 if (IS_ERR(key_ref)) {
474 ret = PTR_ERR(key_ref);
478 ret = key_unlink(key_ref_to_ptr(keyring_ref), key_ref_to_ptr(key_ref));
480 key_ref_put(key_ref);
482 key_ref_put(keyring_ref);
488 * Return a description of a key to userspace.
490 * The key must grant the caller View permission for this to work.
492 * If there's a buffer, we place up to buflen bytes of data into it formatted
493 * in the following way:
495 * type;uid;gid;perm;description<NUL>
497 * If successful, we return the amount of description available, irrespective
498 * of how much we may have copied into the buffer.
500 long keyctl_describe_key(key_serial_t keyid,
504 struct key *key, *instkey;
509 key_ref = lookup_user_key(keyid, KEY_LOOKUP_PARTIAL, KEY_VIEW);
510 if (IS_ERR(key_ref)) {
511 /* viewing a key under construction is permitted if we have the
512 * authorisation token handy */
513 if (PTR_ERR(key_ref) == -EACCES) {
514 instkey = key_get_instantiation_authkey(keyid);
515 if (!IS_ERR(instkey)) {
517 key_ref = lookup_user_key(keyid,
520 if (!IS_ERR(key_ref))
525 ret = PTR_ERR(key_ref);
530 /* calculate how much description we're going to return */
532 tmpbuf = kmalloc(PAGE_SIZE, GFP_KERNEL);
536 key = key_ref_to_ptr(key_ref);
538 ret = snprintf(tmpbuf, PAGE_SIZE - 1,
544 key->description ?: "");
546 /* include a NUL char at the end of the data */
547 if (ret > PAGE_SIZE - 1)
552 /* consider returning the data */
553 if (buffer && buflen > 0) {
557 if (copy_to_user(buffer, tmpbuf, buflen) != 0)
563 key_ref_put(key_ref);
569 * Search the specified keyring and any keyrings it links to for a matching
570 * key. Only keyrings that grant the caller Search permission will be searched
571 * (this includes the starting keyring). Only keys with Search permission can
574 * If successful, the found key will be linked to the destination keyring if
575 * supplied and the key has Link permission, and the found key ID will be
578 long keyctl_keyring_search(key_serial_t ringid,
579 const char __user *_type,
580 const char __user *_description,
581 key_serial_t destringid)
583 struct key_type *ktype;
584 key_ref_t keyring_ref, key_ref, dest_ref;
585 char type[32], *description;
588 /* pull the type and description into kernel space */
589 ret = key_get_type_from_user(type, _type, sizeof(type));
593 description = strndup_user(_description, PAGE_SIZE);
594 if (IS_ERR(description)) {
595 ret = PTR_ERR(description);
599 /* get the keyring at which to begin the search */
600 keyring_ref = lookup_user_key(ringid, 0, KEY_SEARCH);
601 if (IS_ERR(keyring_ref)) {
602 ret = PTR_ERR(keyring_ref);
606 /* get the destination keyring if specified */
609 dest_ref = lookup_user_key(destringid, KEY_LOOKUP_CREATE,
611 if (IS_ERR(dest_ref)) {
612 ret = PTR_ERR(dest_ref);
617 /* find the key type */
618 ktype = key_type_lookup(type);
620 ret = PTR_ERR(ktype);
625 key_ref = keyring_search(keyring_ref, ktype, description);
626 if (IS_ERR(key_ref)) {
627 ret = PTR_ERR(key_ref);
629 /* treat lack or presence of a negative key the same */
635 /* link the resulting key to the destination keyring if we can */
637 ret = key_permission(key_ref, KEY_LINK);
641 ret = key_link(key_ref_to_ptr(dest_ref), key_ref_to_ptr(key_ref));
646 ret = key_ref_to_ptr(key_ref)->serial;
649 key_ref_put(key_ref);
653 key_ref_put(dest_ref);
655 key_ref_put(keyring_ref);
663 * Read a key's payload.
665 * The key must either grant the caller Read permission, or it must grant the
666 * caller Search permission when searched for from the process keyrings.
668 * If successful, we place up to buflen bytes of data into the buffer, if one
669 * is provided, and return the amount of data that is available in the key,
670 * irrespective of how much we copied into the buffer.
672 long keyctl_read_key(key_serial_t keyid, char __user *buffer, size_t buflen)
678 /* find the key first */
679 key_ref = lookup_user_key(keyid, 0, 0);
680 if (IS_ERR(key_ref)) {
685 key = key_ref_to_ptr(key_ref);
687 /* see if we can read it directly */
688 ret = key_permission(key_ref, KEY_READ);
694 /* we can't; see if it's searchable from this process's keyrings
695 * - we automatically take account of the fact that it may be
696 * dangling off an instantiation key
698 if (!is_key_possessed(key_ref)) {
703 /* the key is probably readable - now try to read it */
705 ret = key_validate(key);
708 if (key->type->read) {
709 /* read the data with the semaphore held (since we
711 down_read(&key->sem);
712 ret = key->type->read(key, buffer, buflen);
724 * Change the ownership of a key
726 * The key must grant the caller Setattr permission for this to work, though
727 * the key need not be fully instantiated yet. For the UID to be changed, or
728 * for the GID to be changed to a group the caller is not a member of, the
729 * caller must have sysadmin capability. If either uid or gid is -1 then that
730 * attribute is not changed.
732 * If the UID is to be changed, the new user must have sufficient quota to
733 * accept the key. The quota deduction will be removed from the old user to
734 * the new user should the attribute be changed.
736 * If successful, 0 will be returned.
738 long keyctl_chown_key(key_serial_t id, uid_t uid, gid_t gid)
740 struct key_user *newowner, *zapowner = NULL;
746 if (uid == (uid_t) -1 && gid == (gid_t) -1)
749 key_ref = lookup_user_key(id, KEY_LOOKUP_CREATE | KEY_LOOKUP_PARTIAL,
751 if (IS_ERR(key_ref)) {
752 ret = PTR_ERR(key_ref);
756 key = key_ref_to_ptr(key_ref);
758 /* make the changes with the locks held to prevent chown/chown races */
760 down_write(&key->sem);
762 if (!capable(CAP_SYS_ADMIN)) {
763 /* only the sysadmin can chown a key to some other UID */
764 if (uid != (uid_t) -1 && key->uid != uid)
767 /* only the sysadmin can set the key's GID to a group other
768 * than one of those that the current process subscribes to */
769 if (gid != (gid_t) -1 && gid != key->gid && !in_group_p(gid))
774 if (uid != (uid_t) -1 && uid != key->uid) {
776 newowner = key_user_lookup(uid, current_user_ns());
780 /* transfer the quota burden to the new user */
781 if (test_bit(KEY_FLAG_IN_QUOTA, &key->flags)) {
782 unsigned maxkeys = (uid == 0) ?
783 key_quota_root_maxkeys : key_quota_maxkeys;
784 unsigned maxbytes = (uid == 0) ?
785 key_quota_root_maxbytes : key_quota_maxbytes;
787 spin_lock(&newowner->lock);
788 if (newowner->qnkeys + 1 >= maxkeys ||
789 newowner->qnbytes + key->quotalen >= maxbytes ||
790 newowner->qnbytes + key->quotalen <
795 newowner->qnbytes += key->quotalen;
796 spin_unlock(&newowner->lock);
798 spin_lock(&key->user->lock);
800 key->user->qnbytes -= key->quotalen;
801 spin_unlock(&key->user->lock);
804 atomic_dec(&key->user->nkeys);
805 atomic_inc(&newowner->nkeys);
807 if (test_bit(KEY_FLAG_INSTANTIATED, &key->flags)) {
808 atomic_dec(&key->user->nikeys);
809 atomic_inc(&newowner->nikeys);
812 zapowner = key->user;
813 key->user = newowner;
818 if (gid != (gid_t) -1)
827 key_user_put(zapowner);
832 spin_unlock(&newowner->lock);
839 * Change the permission mask on a key.
841 * The key must grant the caller Setattr permission for this to work, though
842 * the key need not be fully instantiated yet. If the caller does not have
843 * sysadmin capability, it may only change the permission on keys that it owns.
845 long keyctl_setperm_key(key_serial_t id, key_perm_t perm)
852 if (perm & ~(KEY_POS_ALL | KEY_USR_ALL | KEY_GRP_ALL | KEY_OTH_ALL))
855 key_ref = lookup_user_key(id, KEY_LOOKUP_CREATE | KEY_LOOKUP_PARTIAL,
857 if (IS_ERR(key_ref)) {
858 ret = PTR_ERR(key_ref);
862 key = key_ref_to_ptr(key_ref);
864 /* make the changes with the locks held to prevent chown/chmod races */
866 down_write(&key->sem);
868 /* if we're not the sysadmin, we can only change a key that we own */
869 if (capable(CAP_SYS_ADMIN) || key->uid == current_fsuid()) {
881 * Get the destination keyring for instantiation and check that the caller has
882 * Write permission on it.
884 static long get_instantiation_keyring(key_serial_t ringid,
885 struct request_key_auth *rka,
886 struct key **_dest_keyring)
890 *_dest_keyring = NULL;
892 /* just return a NULL pointer if we weren't asked to make a link */
896 /* if a specific keyring is nominated by ID, then use that */
898 dkref = lookup_user_key(ringid, KEY_LOOKUP_CREATE, KEY_WRITE);
900 return PTR_ERR(dkref);
901 *_dest_keyring = key_ref_to_ptr(dkref);
905 if (ringid == KEY_SPEC_REQKEY_AUTH_KEY)
908 /* otherwise specify the destination keyring recorded in the
909 * authorisation key (any KEY_SPEC_*_KEYRING) */
910 if (ringid >= KEY_SPEC_REQUESTOR_KEYRING) {
911 *_dest_keyring = key_get(rka->dest_keyring);
919 * Change the request_key authorisation key on the current process.
921 static int keyctl_change_reqkey_auth(struct key *key)
925 new = prepare_creds();
929 key_put(new->request_key_auth);
930 new->request_key_auth = key_get(key);
932 return commit_creds(new);
936 * Copy the iovec data from userspace
938 static long copy_from_user_iovec(void *buffer, const struct iovec *iov,
941 for (; ioc > 0; ioc--) {
942 if (copy_from_user(buffer, iov->iov_base, iov->iov_len) != 0)
944 buffer += iov->iov_len;
951 * Instantiate a key with the specified payload and link the key into the
952 * destination keyring if one is given.
954 * The caller must have the appropriate instantiation permit set for this to
955 * work (see keyctl_assume_authority). No other permissions are required.
957 * If successful, 0 will be returned.
959 long keyctl_instantiate_key_common(key_serial_t id,
960 const struct iovec *payload_iov,
965 const struct cred *cred = current_cred();
966 struct request_key_auth *rka;
967 struct key *instkey, *dest_keyring;
972 kenter("%d,,%zu,%d", id, plen, ringid);
975 if (plen > 1024 * 1024 - 1)
978 /* the appropriate instantiation authorisation key must have been
979 * assumed before calling this */
981 instkey = cred->request_key_auth;
985 rka = instkey->payload.data;
986 if (rka->target_key->serial != id)
989 /* pull the payload in if one was supplied */
994 payload = kmalloc(plen, GFP_KERNEL);
996 if (plen <= PAGE_SIZE)
999 payload = vmalloc(plen);
1004 ret = copy_from_user_iovec(payload, payload_iov, ioc);
1009 /* find the destination keyring amongst those belonging to the
1010 * requesting task */
1011 ret = get_instantiation_keyring(ringid, rka, &dest_keyring);
1015 /* instantiate the key and link it into a keyring */
1016 ret = key_instantiate_and_link(rka->target_key, payload, plen,
1017 dest_keyring, instkey);
1019 key_put(dest_keyring);
1021 /* discard the assumed authority if it's just been disabled by
1022 * instantiation of the key */
1024 keyctl_change_reqkey_auth(NULL);
1036 * Instantiate a key with the specified payload and link the key into the
1037 * destination keyring if one is given.
1039 * The caller must have the appropriate instantiation permit set for this to
1040 * work (see keyctl_assume_authority). No other permissions are required.
1042 * If successful, 0 will be returned.
1044 long keyctl_instantiate_key(key_serial_t id,
1045 const void __user *_payload,
1047 key_serial_t ringid)
1049 if (_payload && plen) {
1050 struct iovec iov[1] = {
1051 [0].iov_base = (void __user *)_payload,
1055 return keyctl_instantiate_key_common(id, iov, 1, plen, ringid);
1058 return keyctl_instantiate_key_common(id, NULL, 0, 0, ringid);
1062 * Instantiate a key with the specified multipart payload and link the key into
1063 * the destination keyring if one is given.
1065 * The caller must have the appropriate instantiation permit set for this to
1066 * work (see keyctl_assume_authority). No other permissions are required.
1068 * If successful, 0 will be returned.
1070 long keyctl_instantiate_key_iov(key_serial_t id,
1071 const struct iovec __user *_payload_iov,
1073 key_serial_t ringid)
1075 struct iovec iovstack[UIO_FASTIOV], *iov = iovstack;
1078 if (_payload_iov == 0 || ioc == 0)
1081 ret = rw_copy_check_uvector(WRITE, _payload_iov, ioc,
1082 ARRAY_SIZE(iovstack), iovstack, &iov, 1);
1086 goto no_payload_free;
1088 ret = keyctl_instantiate_key_common(id, iov, ioc, ret, ringid);
1090 if (iov != iovstack)
1095 if (iov != iovstack)
1098 return keyctl_instantiate_key_common(id, NULL, 0, 0, ringid);
1102 * Negatively instantiate the key with the given timeout (in seconds) and link
1103 * the key into the destination keyring if one is given.
1105 * The caller must have the appropriate instantiation permit set for this to
1106 * work (see keyctl_assume_authority). No other permissions are required.
1108 * The key and any links to the key will be automatically garbage collected
1109 * after the timeout expires.
1111 * Negative keys are used to rate limit repeated request_key() calls by causing
1112 * them to return -ENOKEY until the negative key expires.
1114 * If successful, 0 will be returned.
1116 long keyctl_negate_key(key_serial_t id, unsigned timeout, key_serial_t ringid)
1118 return keyctl_reject_key(id, timeout, ENOKEY, ringid);
1122 * Negatively instantiate the key with the given timeout (in seconds) and error
1123 * code and link the key into the destination keyring if one is given.
1125 * The caller must have the appropriate instantiation permit set for this to
1126 * work (see keyctl_assume_authority). No other permissions are required.
1128 * The key and any links to the key will be automatically garbage collected
1129 * after the timeout expires.
1131 * Negative keys are used to rate limit repeated request_key() calls by causing
1132 * them to return the specified error code until the negative key expires.
1134 * If successful, 0 will be returned.
1136 long keyctl_reject_key(key_serial_t id, unsigned timeout, unsigned error,
1137 key_serial_t ringid)
1139 const struct cred *cred = current_cred();
1140 struct request_key_auth *rka;
1141 struct key *instkey, *dest_keyring;
1144 kenter("%d,%u,%u,%d", id, timeout, error, ringid);
1146 /* must be a valid error code and mustn't be a kernel special */
1148 error >= MAX_ERRNO ||
1149 error == ERESTARTSYS ||
1150 error == ERESTARTNOINTR ||
1151 error == ERESTARTNOHAND ||
1152 error == ERESTART_RESTARTBLOCK)
1155 /* the appropriate instantiation authorisation key must have been
1156 * assumed before calling this */
1158 instkey = cred->request_key_auth;
1162 rka = instkey->payload.data;
1163 if (rka->target_key->serial != id)
1166 /* find the destination keyring if present (which must also be
1168 ret = get_instantiation_keyring(ringid, rka, &dest_keyring);
1172 /* instantiate the key and link it into a keyring */
1173 ret = key_reject_and_link(rka->target_key, timeout, error,
1174 dest_keyring, instkey);
1176 key_put(dest_keyring);
1178 /* discard the assumed authority if it's just been disabled by
1179 * instantiation of the key */
1181 keyctl_change_reqkey_auth(NULL);
1188 * Read or set the default keyring in which request_key() will cache keys and
1189 * return the old setting.
1191 * If a process keyring is specified then this will be created if it doesn't
1192 * yet exist. The old setting will be returned if successful.
1194 long keyctl_set_reqkey_keyring(int reqkey_defl)
1197 int ret, old_setting;
1199 old_setting = current_cred_xxx(jit_keyring);
1201 if (reqkey_defl == KEY_REQKEY_DEFL_NO_CHANGE)
1204 new = prepare_creds();
1208 switch (reqkey_defl) {
1209 case KEY_REQKEY_DEFL_THREAD_KEYRING:
1210 ret = install_thread_keyring_to_cred(new);
1215 case KEY_REQKEY_DEFL_PROCESS_KEYRING:
1216 ret = install_process_keyring_to_cred(new);
1224 case KEY_REQKEY_DEFL_DEFAULT:
1225 case KEY_REQKEY_DEFL_SESSION_KEYRING:
1226 case KEY_REQKEY_DEFL_USER_KEYRING:
1227 case KEY_REQKEY_DEFL_USER_SESSION_KEYRING:
1228 case KEY_REQKEY_DEFL_REQUESTOR_KEYRING:
1231 case KEY_REQKEY_DEFL_NO_CHANGE:
1232 case KEY_REQKEY_DEFL_GROUP_KEYRING:
1239 new->jit_keyring = reqkey_defl;
1248 * Set or clear the timeout on a key.
1250 * Either the key must grant the caller Setattr permission or else the caller
1251 * must hold an instantiation authorisation token for the key.
1253 * The timeout is either 0 to clear the timeout, or a number of seconds from
1254 * the current time. The key and any links to the key will be automatically
1255 * garbage collected after the timeout expires.
1257 * If successful, 0 is returned.
1259 long keyctl_set_timeout(key_serial_t id, unsigned timeout)
1261 struct key *key, *instkey;
1265 key_ref = lookup_user_key(id, KEY_LOOKUP_CREATE | KEY_LOOKUP_PARTIAL,
1267 if (IS_ERR(key_ref)) {
1268 /* setting the timeout on a key under construction is permitted
1269 * if we have the authorisation token handy */
1270 if (PTR_ERR(key_ref) == -EACCES) {
1271 instkey = key_get_instantiation_authkey(id);
1272 if (!IS_ERR(instkey)) {
1274 key_ref = lookup_user_key(id,
1277 if (!IS_ERR(key_ref))
1282 ret = PTR_ERR(key_ref);
1287 key = key_ref_to_ptr(key_ref);
1288 key_set_timeout(key, timeout);
1297 * Assume (or clear) the authority to instantiate the specified key.
1299 * This sets the authoritative token currently in force for key instantiation.
1300 * This must be done for a key to be instantiated. It has the effect of making
1301 * available all the keys from the caller of the request_key() that created a
1302 * key to request_key() calls made by the caller of this function.
1304 * The caller must have the instantiation key in their process keyrings with a
1305 * Search permission grant available to the caller.
1307 * If the ID given is 0, then the setting will be cleared and 0 returned.
1309 * If the ID given has a matching an authorisation key, then that key will be
1310 * set and its ID will be returned. The authorisation key can be read to get
1311 * the callout information passed to request_key().
1313 long keyctl_assume_authority(key_serial_t id)
1315 struct key *authkey;
1318 /* special key IDs aren't permitted */
1323 /* we divest ourselves of authority if given an ID of 0 */
1325 ret = keyctl_change_reqkey_auth(NULL);
1329 /* attempt to assume the authority temporarily granted to us whilst we
1330 * instantiate the specified key
1331 * - the authorisation key must be in the current task's keyrings
1334 authkey = key_get_instantiation_authkey(id);
1335 if (IS_ERR(authkey)) {
1336 ret = PTR_ERR(authkey);
1340 ret = keyctl_change_reqkey_auth(authkey);
1345 ret = authkey->serial;
1351 * Get a key's the LSM security label.
1353 * The key must grant the caller View permission for this to work.
1355 * If there's a buffer, then up to buflen bytes of data will be placed into it.
1357 * If successful, the amount of information available will be returned,
1358 * irrespective of how much was copied (including the terminal NUL).
1360 long keyctl_get_security(key_serial_t keyid,
1361 char __user *buffer,
1364 struct key *key, *instkey;
1369 key_ref = lookup_user_key(keyid, KEY_LOOKUP_PARTIAL, KEY_VIEW);
1370 if (IS_ERR(key_ref)) {
1371 if (PTR_ERR(key_ref) != -EACCES)
1372 return PTR_ERR(key_ref);
1374 /* viewing a key under construction is also permitted if we
1375 * have the authorisation token handy */
1376 instkey = key_get_instantiation_authkey(keyid);
1377 if (IS_ERR(instkey))
1378 return PTR_ERR(instkey);
1381 key_ref = lookup_user_key(keyid, KEY_LOOKUP_PARTIAL, 0);
1382 if (IS_ERR(key_ref))
1383 return PTR_ERR(key_ref);
1386 key = key_ref_to_ptr(key_ref);
1387 ret = security_key_getsecurity(key, &context);
1389 /* if no information was returned, give userspace an empty
1392 if (buffer && buflen > 0 &&
1393 copy_to_user(buffer, "", 1) != 0)
1395 } else if (ret > 0) {
1396 /* return as much data as there's room for */
1397 if (buffer && buflen > 0) {
1401 if (copy_to_user(buffer, context, buflen) != 0)
1408 key_ref_put(key_ref);
1413 * Attempt to install the calling process's session keyring on the process's
1416 * The keyring must exist and must grant the caller LINK permission, and the
1417 * parent process must be single-threaded and must have the same effective
1418 * ownership as this process and mustn't be SUID/SGID.
1420 * The keyring will be emplaced on the parent when it next resumes userspace.
1422 * If successful, 0 will be returned.
1424 long keyctl_session_to_parent(void)
1426 #ifdef TIF_NOTIFY_RESUME
1427 struct task_struct *me, *parent;
1428 const struct cred *mycred, *pcred;
1429 struct cred *cred, *oldcred;
1430 key_ref_t keyring_r;
1433 keyring_r = lookup_user_key(KEY_SPEC_SESSION_KEYRING, 0, KEY_LINK);
1434 if (IS_ERR(keyring_r))
1435 return PTR_ERR(keyring_r);
1437 /* our parent is going to need a new cred struct, a new tgcred struct
1438 * and new security data, so we allocate them here to prevent ENOMEM in
1441 cred = cred_alloc_blank();
1445 cred->tgcred->session_keyring = key_ref_to_ptr(keyring_r);
1450 write_lock_irq(&tasklist_lock);
1452 parent = me->real_parent;
1455 /* the parent mustn't be init and mustn't be a kernel thread */
1456 if (parent->pid <= 1 || !parent->mm)
1459 /* the parent must be single threaded */
1460 if (!thread_group_empty(parent))
1463 /* the parent and the child must have different session keyrings or
1464 * there's no point */
1465 mycred = current_cred();
1466 pcred = __task_cred(parent);
1467 if (mycred == pcred ||
1468 mycred->tgcred->session_keyring == pcred->tgcred->session_keyring)
1471 /* the parent must have the same effective ownership and mustn't be
1473 if (pcred->uid != mycred->euid ||
1474 pcred->euid != mycred->euid ||
1475 pcred->suid != mycred->euid ||
1476 pcred->gid != mycred->egid ||
1477 pcred->egid != mycred->egid ||
1478 pcred->sgid != mycred->egid)
1481 /* the keyrings must have the same UID */
1482 if ((pcred->tgcred->session_keyring &&
1483 pcred->tgcred->session_keyring->uid != mycred->euid) ||
1484 mycred->tgcred->session_keyring->uid != mycred->euid)
1487 /* if there's an already pending keyring replacement, then we replace
1489 oldcred = parent->replacement_session_keyring;
1491 /* the replacement session keyring is applied just prior to userspace
1493 parent->replacement_session_keyring = cred;
1495 set_ti_thread_flag(task_thread_info(parent), TIF_NOTIFY_RESUME);
1497 write_unlock_irq(&tasklist_lock);
1506 write_unlock_irq(&tasklist_lock);
1512 key_ref_put(keyring_r);
1515 #else /* !TIF_NOTIFY_RESUME */
1517 * To be removed when TIF_NOTIFY_RESUME has been implemented on
1520 #warning TIF_NOTIFY_RESUME not implemented
1522 #endif /* !TIF_NOTIFY_RESUME */
1526 * The key control system call
1528 SYSCALL_DEFINE5(keyctl, int, option, unsigned long, arg2, unsigned long, arg3,
1529 unsigned long, arg4, unsigned long, arg5)
1532 case KEYCTL_GET_KEYRING_ID:
1533 return keyctl_get_keyring_ID((key_serial_t) arg2,
1536 case KEYCTL_JOIN_SESSION_KEYRING:
1537 return keyctl_join_session_keyring((const char __user *) arg2);
1540 return keyctl_update_key((key_serial_t) arg2,
1541 (const void __user *) arg3,
1545 return keyctl_revoke_key((key_serial_t) arg2);
1547 case KEYCTL_DESCRIBE:
1548 return keyctl_describe_key((key_serial_t) arg2,
1549 (char __user *) arg3,
1553 return keyctl_keyring_clear((key_serial_t) arg2);
1556 return keyctl_keyring_link((key_serial_t) arg2,
1557 (key_serial_t) arg3);
1560 return keyctl_keyring_unlink((key_serial_t) arg2,
1561 (key_serial_t) arg3);
1564 return keyctl_keyring_search((key_serial_t) arg2,
1565 (const char __user *) arg3,
1566 (const char __user *) arg4,
1567 (key_serial_t) arg5);
1570 return keyctl_read_key((key_serial_t) arg2,
1571 (char __user *) arg3,
1575 return keyctl_chown_key((key_serial_t) arg2,
1579 case KEYCTL_SETPERM:
1580 return keyctl_setperm_key((key_serial_t) arg2,
1583 case KEYCTL_INSTANTIATE:
1584 return keyctl_instantiate_key((key_serial_t) arg2,
1585 (const void __user *) arg3,
1587 (key_serial_t) arg5);
1590 return keyctl_negate_key((key_serial_t) arg2,
1592 (key_serial_t) arg4);
1594 case KEYCTL_SET_REQKEY_KEYRING:
1595 return keyctl_set_reqkey_keyring(arg2);
1597 case KEYCTL_SET_TIMEOUT:
1598 return keyctl_set_timeout((key_serial_t) arg2,
1601 case KEYCTL_ASSUME_AUTHORITY:
1602 return keyctl_assume_authority((key_serial_t) arg2);
1604 case KEYCTL_GET_SECURITY:
1605 return keyctl_get_security((key_serial_t) arg2,
1606 (char __user *) arg3,
1609 case KEYCTL_SESSION_TO_PARENT:
1610 return keyctl_session_to_parent();
1613 return keyctl_reject_key((key_serial_t) arg2,
1616 (key_serial_t) arg5);
1618 case KEYCTL_INSTANTIATE_IOV:
1619 return keyctl_instantiate_key_iov(
1620 (key_serial_t) arg2,
1621 (const struct iovec __user *) arg3,
1623 (key_serial_t) arg5);