1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /* Userspace key control operations
4 * Copyright (C) 2004-5 Red Hat, Inc. All Rights Reserved.
5 * Written by David Howells (dhowells@redhat.com)
8 #include <linux/init.h>
9 #include <linux/sched.h>
10 #include <linux/sched/task.h>
11 #include <linux/slab.h>
12 #include <linux/syscalls.h>
13 #include <linux/key.h>
14 #include <linux/keyctl.h>
16 #include <linux/capability.h>
17 #include <linux/cred.h>
18 #include <linux/string.h>
19 #include <linux/err.h>
20 #include <linux/vmalloc.h>
21 #include <linux/security.h>
22 #include <linux/uio.h>
23 #include <linux/uaccess.h>
24 #include <keys/request_key_auth-type.h>
27 #define KEY_MAX_DESC_SIZE 4096
29 static const unsigned char keyrings_capabilities[2] = {
30 [0] = (KEYCTL_CAPS0_CAPABILITIES |
31 (IS_ENABLED(CONFIG_PERSISTENT_KEYRINGS) ? KEYCTL_CAPS0_PERSISTENT_KEYRINGS : 0) |
32 (IS_ENABLED(CONFIG_KEY_DH_OPERATIONS) ? KEYCTL_CAPS0_DIFFIE_HELLMAN : 0) |
33 (IS_ENABLED(CONFIG_ASYMMETRIC_KEY_TYPE) ? KEYCTL_CAPS0_PUBLIC_KEY : 0) |
34 (IS_ENABLED(CONFIG_BIG_KEYS) ? KEYCTL_CAPS0_BIG_KEY : 0) |
35 KEYCTL_CAPS0_INVALIDATE |
36 KEYCTL_CAPS0_RESTRICT_KEYRING |
39 [1] = (KEYCTL_CAPS1_NS_KEYRING_NAME |
40 KEYCTL_CAPS1_NS_KEY_TAG |
41 (IS_ENABLED(CONFIG_KEY_NOTIFICATIONS) ? KEYCTL_CAPS1_NOTIFICATIONS : 0)
45 static int key_get_type_from_user(char *type,
46 const char __user *_type,
51 ret = strncpy_from_user(type, _type, len);
54 if (ret == 0 || ret >= len)
63 * Extract the description of a new key from userspace and either add it as a
64 * new key to the specified keyring or update a matching key in that keyring.
66 * If the description is NULL or an empty string, the key type is asked to
67 * generate one from the payload.
69 * The keyring must be writable so that we can attach the key to it.
71 * If successful, the new key's serial number is returned, otherwise an error
74 SYSCALL_DEFINE5(add_key, const char __user *, _type,
75 const char __user *, _description,
76 const void __user *, _payload,
80 key_ref_t keyring_ref, key_ref;
81 char type[32], *description;
86 if (plen > 1024 * 1024 - 1)
89 /* draw all the data into kernel space */
90 ret = key_get_type_from_user(type, _type, sizeof(type));
96 description = strndup_user(_description, KEY_MAX_DESC_SIZE);
97 if (IS_ERR(description)) {
98 ret = PTR_ERR(description);
104 } else if ((description[0] == '.') &&
105 (strncmp(type, "keyring", 7) == 0)) {
111 /* pull the payload in if one was supplied */
116 payload = kvmalloc(plen, GFP_KERNEL);
121 if (copy_from_user(payload, _payload, plen) != 0)
125 /* find the target keyring (which must be writable) */
126 keyring_ref = lookup_user_key(ringid, KEY_LOOKUP_CREATE, KEY_NEED_WRITE);
127 if (IS_ERR(keyring_ref)) {
128 ret = PTR_ERR(keyring_ref);
132 /* create or update the requested key and add it to the target
134 key_ref = key_create_or_update(keyring_ref, type, description,
135 payload, plen, KEY_PERM_UNDEF,
137 if (!IS_ERR(key_ref)) {
138 ret = key_ref_to_ptr(key_ref)->serial;
139 key_ref_put(key_ref);
142 ret = PTR_ERR(key_ref);
145 key_ref_put(keyring_ref);
147 kvfree_sensitive(payload, plen);
155 * Search the process keyrings and keyring trees linked from those for a
156 * matching key. Keyrings must have appropriate Search permission to be
159 * If a key is found, it will be attached to the destination keyring if there's
160 * one specified and the serial number of the key will be returned.
162 * If no key is found, /sbin/request-key will be invoked if _callout_info is
163 * non-NULL in an attempt to create a key. The _callout_info string will be
164 * passed to /sbin/request-key to aid with completing the request. If the
165 * _callout_info string is "" then it will be changed to "-".
167 SYSCALL_DEFINE4(request_key, const char __user *, _type,
168 const char __user *, _description,
169 const char __user *, _callout_info,
170 key_serial_t, destringid)
172 struct key_type *ktype;
176 char type[32], *description, *callout_info;
179 /* pull the type into kernel space */
180 ret = key_get_type_from_user(type, _type, sizeof(type));
184 /* pull the description into kernel space */
185 description = strndup_user(_description, KEY_MAX_DESC_SIZE);
186 if (IS_ERR(description)) {
187 ret = PTR_ERR(description);
191 /* pull the callout info into kernel space */
195 callout_info = strndup_user(_callout_info, PAGE_SIZE);
196 if (IS_ERR(callout_info)) {
197 ret = PTR_ERR(callout_info);
200 callout_len = strlen(callout_info);
203 /* get the destination keyring if specified */
206 dest_ref = lookup_user_key(destringid, KEY_LOOKUP_CREATE,
208 if (IS_ERR(dest_ref)) {
209 ret = PTR_ERR(dest_ref);
214 /* find the key type */
215 ktype = key_type_lookup(type);
217 ret = PTR_ERR(ktype);
222 key = request_key_and_link(ktype, description, NULL, callout_info,
223 callout_len, NULL, key_ref_to_ptr(dest_ref),
230 /* wait for the key to finish being constructed */
231 ret = wait_for_key_construction(key, 1);
242 key_ref_put(dest_ref);
252 * Get the ID of the specified process keyring.
254 * The requested keyring must have search permission to be found.
256 * If successful, the ID of the requested keyring will be returned.
258 long keyctl_get_keyring_ID(key_serial_t id, int create)
261 unsigned long lflags;
264 lflags = create ? KEY_LOOKUP_CREATE : 0;
265 key_ref = lookup_user_key(id, lflags, KEY_NEED_SEARCH);
266 if (IS_ERR(key_ref)) {
267 ret = PTR_ERR(key_ref);
271 ret = key_ref_to_ptr(key_ref)->serial;
272 key_ref_put(key_ref);
278 * Join a (named) session keyring.
280 * Create and join an anonymous session keyring or join a named session
281 * keyring, creating it if necessary. A named session keyring must have Search
282 * permission for it to be joined. Session keyrings without this permit will
283 * be skipped over. It is not permitted for userspace to create or join
284 * keyrings whose name begin with a dot.
286 * If successful, the ID of the joined session keyring will be returned.
288 long keyctl_join_session_keyring(const char __user *_name)
293 /* fetch the name from userspace */
296 name = strndup_user(_name, KEY_MAX_DESC_SIZE);
307 /* join the session */
308 ret = join_session_keyring(name);
316 * Update a key's data payload from the given data.
318 * The key must grant the caller Write permission and the key type must support
319 * updating for this to work. A negative key can be positively instantiated
322 * If successful, 0 will be returned. If the key type does not support
323 * updating, then -EOPNOTSUPP will be returned.
325 long keyctl_update_key(key_serial_t id,
326 const void __user *_payload,
334 if (plen > PAGE_SIZE)
337 /* pull the payload in if one was supplied */
341 payload = kvmalloc(plen, GFP_KERNEL);
346 if (copy_from_user(payload, _payload, plen) != 0)
350 /* find the target key (which must be writable) */
351 key_ref = lookup_user_key(id, 0, KEY_NEED_WRITE);
352 if (IS_ERR(key_ref)) {
353 ret = PTR_ERR(key_ref);
358 ret = key_update(key_ref, payload, plen);
360 key_ref_put(key_ref);
362 kvfree_sensitive(payload, plen);
370 * The key must be grant the caller Write or Setattr permission for this to
371 * work. The key type should give up its quota claim when revoked. The key
372 * and any links to the key will be automatically garbage collected after a
373 * certain amount of time (/proc/sys/kernel/keys/gc_delay).
375 * Keys with KEY_FLAG_KEEP set should not be revoked.
377 * If successful, 0 is returned.
379 long keyctl_revoke_key(key_serial_t id)
385 key_ref = lookup_user_key(id, 0, KEY_NEED_WRITE);
386 if (IS_ERR(key_ref)) {
387 ret = PTR_ERR(key_ref);
390 key_ref = lookup_user_key(id, 0, KEY_NEED_SETATTR);
391 if (IS_ERR(key_ref)) {
392 ret = PTR_ERR(key_ref);
397 key = key_ref_to_ptr(key_ref);
399 if (test_bit(KEY_FLAG_KEEP, &key->flags))
404 key_ref_put(key_ref);
412 * The key must be grant the caller Invalidate permission for this to work.
413 * The key and any links to the key will be automatically garbage collected
416 * Keys with KEY_FLAG_KEEP set should not be invalidated.
418 * If successful, 0 is returned.
420 long keyctl_invalidate_key(key_serial_t id)
428 key_ref = lookup_user_key(id, 0, KEY_NEED_SEARCH);
429 if (IS_ERR(key_ref)) {
430 ret = PTR_ERR(key_ref);
432 /* Root is permitted to invalidate certain special keys */
433 if (capable(CAP_SYS_ADMIN)) {
434 key_ref = lookup_user_key(id, 0, KEY_SYSADMIN_OVERRIDE);
437 if (test_bit(KEY_FLAG_ROOT_CAN_INVAL,
438 &key_ref_to_ptr(key_ref)->flags))
447 key = key_ref_to_ptr(key_ref);
449 if (test_bit(KEY_FLAG_KEEP, &key->flags))
454 key_ref_put(key_ref);
456 kleave(" = %ld", ret);
461 * Clear the specified keyring, creating an empty process keyring if one of the
462 * special keyring IDs is used.
464 * The keyring must grant the caller Write permission and not have
465 * KEY_FLAG_KEEP set for this to work. If successful, 0 will be returned.
467 long keyctl_keyring_clear(key_serial_t ringid)
469 key_ref_t keyring_ref;
473 keyring_ref = lookup_user_key(ringid, KEY_LOOKUP_CREATE, KEY_NEED_WRITE);
474 if (IS_ERR(keyring_ref)) {
475 ret = PTR_ERR(keyring_ref);
477 /* Root is permitted to invalidate certain special keyrings */
478 if (capable(CAP_SYS_ADMIN)) {
479 keyring_ref = lookup_user_key(ringid, 0,
480 KEY_SYSADMIN_OVERRIDE);
481 if (IS_ERR(keyring_ref))
483 if (test_bit(KEY_FLAG_ROOT_CAN_CLEAR,
484 &key_ref_to_ptr(keyring_ref)->flags))
493 keyring = key_ref_to_ptr(keyring_ref);
494 if (test_bit(KEY_FLAG_KEEP, &keyring->flags))
497 ret = keyring_clear(keyring);
499 key_ref_put(keyring_ref);
505 * Create a link from a keyring to a key if there's no matching key in the
506 * keyring, otherwise replace the link to the matching key with a link to the
509 * The key must grant the caller Link permission and the keyring must grant
510 * the caller Write permission. Furthermore, if an additional link is created,
511 * the keyring's quota will be extended.
513 * If successful, 0 will be returned.
515 long keyctl_keyring_link(key_serial_t id, key_serial_t ringid)
517 key_ref_t keyring_ref, key_ref;
520 keyring_ref = lookup_user_key(ringid, KEY_LOOKUP_CREATE, KEY_NEED_WRITE);
521 if (IS_ERR(keyring_ref)) {
522 ret = PTR_ERR(keyring_ref);
526 key_ref = lookup_user_key(id, KEY_LOOKUP_CREATE, KEY_NEED_LINK);
527 if (IS_ERR(key_ref)) {
528 ret = PTR_ERR(key_ref);
532 ret = key_link(key_ref_to_ptr(keyring_ref), key_ref_to_ptr(key_ref));
534 key_ref_put(key_ref);
536 key_ref_put(keyring_ref);
542 * Unlink a key from a keyring.
544 * The keyring must grant the caller Write permission for this to work; the key
545 * itself need not grant the caller anything. If the last link to a key is
546 * removed then that key will be scheduled for destruction.
548 * Keys or keyrings with KEY_FLAG_KEEP set should not be unlinked.
550 * If successful, 0 will be returned.
552 long keyctl_keyring_unlink(key_serial_t id, key_serial_t ringid)
554 key_ref_t keyring_ref, key_ref;
555 struct key *keyring, *key;
558 keyring_ref = lookup_user_key(ringid, 0, KEY_NEED_WRITE);
559 if (IS_ERR(keyring_ref)) {
560 ret = PTR_ERR(keyring_ref);
564 key_ref = lookup_user_key(id, KEY_LOOKUP_PARTIAL, KEY_NEED_UNLINK);
565 if (IS_ERR(key_ref)) {
566 ret = PTR_ERR(key_ref);
570 keyring = key_ref_to_ptr(keyring_ref);
571 key = key_ref_to_ptr(key_ref);
572 if (test_bit(KEY_FLAG_KEEP, &keyring->flags) &&
573 test_bit(KEY_FLAG_KEEP, &key->flags))
576 ret = key_unlink(keyring, key);
578 key_ref_put(key_ref);
580 key_ref_put(keyring_ref);
586 * Move a link to a key from one keyring to another, displacing any matching
587 * key from the destination keyring.
589 * The key must grant the caller Link permission and both keyrings must grant
590 * the caller Write permission. There must also be a link in the from keyring
591 * to the key. If both keyrings are the same, nothing is done.
593 * If successful, 0 will be returned.
595 long keyctl_keyring_move(key_serial_t id, key_serial_t from_ringid,
596 key_serial_t to_ringid, unsigned int flags)
598 key_ref_t key_ref, from_ref, to_ref;
601 if (flags & ~KEYCTL_MOVE_EXCL)
604 key_ref = lookup_user_key(id, KEY_LOOKUP_CREATE, KEY_NEED_LINK);
606 return PTR_ERR(key_ref);
608 from_ref = lookup_user_key(from_ringid, 0, KEY_NEED_WRITE);
609 if (IS_ERR(from_ref)) {
610 ret = PTR_ERR(from_ref);
614 to_ref = lookup_user_key(to_ringid, KEY_LOOKUP_CREATE, KEY_NEED_WRITE);
615 if (IS_ERR(to_ref)) {
616 ret = PTR_ERR(to_ref);
620 ret = key_move(key_ref_to_ptr(key_ref), key_ref_to_ptr(from_ref),
621 key_ref_to_ptr(to_ref), flags);
625 key_ref_put(from_ref);
627 key_ref_put(key_ref);
632 * Return a description of a key to userspace.
634 * The key must grant the caller View permission for this to work.
636 * If there's a buffer, we place up to buflen bytes of data into it formatted
637 * in the following way:
639 * type;uid;gid;perm;description<NUL>
641 * If successful, we return the amount of description available, irrespective
642 * of how much we may have copied into the buffer.
644 long keyctl_describe_key(key_serial_t keyid,
648 struct key *key, *instkey;
652 int desclen, infolen;
654 key_ref = lookup_user_key(keyid, KEY_LOOKUP_PARTIAL, KEY_NEED_VIEW);
655 if (IS_ERR(key_ref)) {
656 /* viewing a key under construction is permitted if we have the
657 * authorisation token handy */
658 if (PTR_ERR(key_ref) == -EACCES) {
659 instkey = key_get_instantiation_authkey(keyid);
660 if (!IS_ERR(instkey)) {
662 key_ref = lookup_user_key(keyid,
664 KEY_AUTHTOKEN_OVERRIDE);
665 if (!IS_ERR(key_ref))
670 ret = PTR_ERR(key_ref);
675 key = key_ref_to_ptr(key_ref);
676 desclen = strlen(key->description);
678 /* calculate how much information we're going to return */
680 infobuf = kasprintf(GFP_KERNEL,
683 from_kuid_munged(current_user_ns(), key->uid),
684 from_kgid_munged(current_user_ns(), key->gid),
688 infolen = strlen(infobuf);
689 ret = infolen + desclen + 1;
691 /* consider returning the data */
692 if (buffer && buflen >= ret) {
693 if (copy_to_user(buffer, infobuf, infolen) != 0 ||
694 copy_to_user(buffer + infolen, key->description,
701 key_ref_put(key_ref);
707 * Search the specified keyring and any keyrings it links to for a matching
708 * key. Only keyrings that grant the caller Search permission will be searched
709 * (this includes the starting keyring). Only keys with Search permission can
712 * If successful, the found key will be linked to the destination keyring if
713 * supplied and the key has Link permission, and the found key ID will be
716 long keyctl_keyring_search(key_serial_t ringid,
717 const char __user *_type,
718 const char __user *_description,
719 key_serial_t destringid)
721 struct key_type *ktype;
722 key_ref_t keyring_ref, key_ref, dest_ref;
723 char type[32], *description;
726 /* pull the type and description into kernel space */
727 ret = key_get_type_from_user(type, _type, sizeof(type));
731 description = strndup_user(_description, KEY_MAX_DESC_SIZE);
732 if (IS_ERR(description)) {
733 ret = PTR_ERR(description);
737 /* get the keyring at which to begin the search */
738 keyring_ref = lookup_user_key(ringid, 0, KEY_NEED_SEARCH);
739 if (IS_ERR(keyring_ref)) {
740 ret = PTR_ERR(keyring_ref);
744 /* get the destination keyring if specified */
747 dest_ref = lookup_user_key(destringid, KEY_LOOKUP_CREATE,
749 if (IS_ERR(dest_ref)) {
750 ret = PTR_ERR(dest_ref);
755 /* find the key type */
756 ktype = key_type_lookup(type);
758 ret = PTR_ERR(ktype);
763 key_ref = keyring_search(keyring_ref, ktype, description, true);
764 if (IS_ERR(key_ref)) {
765 ret = PTR_ERR(key_ref);
767 /* treat lack or presence of a negative key the same */
773 /* link the resulting key to the destination keyring if we can */
775 ret = key_permission(key_ref, KEY_NEED_LINK);
779 ret = key_link(key_ref_to_ptr(dest_ref), key_ref_to_ptr(key_ref));
784 ret = key_ref_to_ptr(key_ref)->serial;
787 key_ref_put(key_ref);
791 key_ref_put(dest_ref);
793 key_ref_put(keyring_ref);
801 * Call the read method
803 static long __keyctl_read_key(struct key *key, char *buffer, size_t buflen)
807 down_read(&key->sem);
808 ret = key_validate(key);
810 ret = key->type->read(key, buffer, buflen);
816 * Read a key's payload.
818 * The key must either grant the caller Read permission, or it must grant the
819 * caller Search permission when searched for from the process keyrings.
821 * If successful, we place up to buflen bytes of data into the buffer, if one
822 * is provided, and return the amount of data that is available in the key,
823 * irrespective of how much we copied into the buffer.
825 long keyctl_read_key(key_serial_t keyid, char __user *buffer, size_t buflen)
830 char *key_data = NULL;
833 /* find the key first */
834 key_ref = lookup_user_key(keyid, 0, KEY_DEFER_PERM_CHECK);
835 if (IS_ERR(key_ref)) {
840 key = key_ref_to_ptr(key_ref);
842 ret = key_read_state(key);
844 goto key_put_out; /* Negatively instantiated */
846 /* see if we can read it directly */
847 ret = key_permission(key_ref, KEY_NEED_READ);
853 /* we can't; see if it's searchable from this process's keyrings
854 * - we automatically take account of the fact that it may be
855 * dangling off an instantiation key
857 if (!is_key_possessed(key_ref)) {
862 /* the key is probably readable - now try to read it */
864 if (!key->type->read) {
869 if (!buffer || !buflen) {
870 /* Get the key length from the read method */
871 ret = __keyctl_read_key(key, NULL, 0);
876 * Read the data with the semaphore held (since we might sleep)
877 * to protect against the key being updated or revoked.
879 * Allocating a temporary buffer to hold the keys before
880 * transferring them to user buffer to avoid potential
881 * deadlock involving page fault and mmap_lock.
883 * key_data_len = (buflen <= PAGE_SIZE)
884 * ? buflen : actual length of key data
886 * This prevents allocating arbitrary large buffer which can
887 * be much larger than the actual key length. In the latter case,
888 * at least 2 passes of this loop is required.
890 key_data_len = (buflen <= PAGE_SIZE) ? buflen : 0;
893 key_data = kvmalloc(key_data_len, GFP_KERNEL);
900 ret = __keyctl_read_key(key, key_data, key_data_len);
903 * Read methods will just return the required length without
904 * any copying if the provided length isn't large enough.
906 if (ret <= 0 || ret > buflen)
910 * The key may change (unlikely) in between 2 consecutive
911 * __keyctl_read_key() calls. In this case, we reallocate
912 * a larger buffer and redo the key read when
913 * key_data_len < ret <= buflen.
915 if (ret > key_data_len) {
916 if (unlikely(key_data))
917 kvfree_sensitive(key_data, key_data_len);
919 continue; /* Allocate buffer */
922 if (copy_to_user(buffer, key_data, ret))
926 kvfree_sensitive(key_data, key_data_len);
935 * Change the ownership of a key
937 * The key must grant the caller Setattr permission for this to work, though
938 * the key need not be fully instantiated yet. For the UID to be changed, or
939 * for the GID to be changed to a group the caller is not a member of, the
940 * caller must have sysadmin capability. If either uid or gid is -1 then that
941 * attribute is not changed.
943 * If the UID is to be changed, the new user must have sufficient quota to
944 * accept the key. The quota deduction will be removed from the old user to
945 * the new user should the attribute be changed.
947 * If successful, 0 will be returned.
949 long keyctl_chown_key(key_serial_t id, uid_t user, gid_t group)
951 struct key_user *newowner, *zapowner = NULL;
958 uid = make_kuid(current_user_ns(), user);
959 gid = make_kgid(current_user_ns(), group);
961 if ((user != (uid_t) -1) && !uid_valid(uid))
963 if ((group != (gid_t) -1) && !gid_valid(gid))
967 if (user == (uid_t) -1 && group == (gid_t) -1)
970 key_ref = lookup_user_key(id, KEY_LOOKUP_CREATE | KEY_LOOKUP_PARTIAL,
972 if (IS_ERR(key_ref)) {
973 ret = PTR_ERR(key_ref);
977 key = key_ref_to_ptr(key_ref);
979 /* make the changes with the locks held to prevent chown/chown races */
981 down_write(&key->sem);
984 bool is_privileged_op = false;
986 /* only the sysadmin can chown a key to some other UID */
987 if (user != (uid_t) -1 && !uid_eq(key->uid, uid))
988 is_privileged_op = true;
990 /* only the sysadmin can set the key's GID to a group other
991 * than one of those that the current process subscribes to */
992 if (group != (gid_t) -1 && !gid_eq(gid, key->gid) && !in_group_p(gid))
993 is_privileged_op = true;
995 if (is_privileged_op && !capable(CAP_SYS_ADMIN))
1000 if (user != (uid_t) -1 && !uid_eq(uid, key->uid)) {
1002 newowner = key_user_lookup(uid);
1006 /* transfer the quota burden to the new user */
1007 if (test_bit(KEY_FLAG_IN_QUOTA, &key->flags)) {
1008 unsigned maxkeys = uid_eq(uid, GLOBAL_ROOT_UID) ?
1009 key_quota_root_maxkeys : key_quota_maxkeys;
1010 unsigned maxbytes = uid_eq(uid, GLOBAL_ROOT_UID) ?
1011 key_quota_root_maxbytes : key_quota_maxbytes;
1013 spin_lock(&newowner->lock);
1014 if (newowner->qnkeys + 1 > maxkeys ||
1015 newowner->qnbytes + key->quotalen > maxbytes ||
1016 newowner->qnbytes + key->quotalen <
1021 newowner->qnbytes += key->quotalen;
1022 spin_unlock(&newowner->lock);
1024 spin_lock(&key->user->lock);
1025 key->user->qnkeys--;
1026 key->user->qnbytes -= key->quotalen;
1027 spin_unlock(&key->user->lock);
1030 atomic_dec(&key->user->nkeys);
1031 atomic_inc(&newowner->nkeys);
1033 if (key->state != KEY_IS_UNINSTANTIATED) {
1034 atomic_dec(&key->user->nikeys);
1035 atomic_inc(&newowner->nikeys);
1038 zapowner = key->user;
1039 key->user = newowner;
1043 /* change the GID */
1044 if (group != (gid_t) -1)
1047 notify_key(key, NOTIFY_KEY_SETATTR, 0);
1051 up_write(&key->sem);
1054 key_user_put(zapowner);
1059 spin_unlock(&newowner->lock);
1060 zapowner = newowner;
1066 * Change the permission mask on a key.
1068 * The key must grant the caller Setattr permission for this to work, though
1069 * the key need not be fully instantiated yet. If the caller does not have
1070 * sysadmin capability, it may only change the permission on keys that it owns.
1072 long keyctl_setperm_key(key_serial_t id, key_perm_t perm)
1079 if (perm & ~(KEY_POS_ALL | KEY_USR_ALL | KEY_GRP_ALL | KEY_OTH_ALL))
1082 key_ref = lookup_user_key(id, KEY_LOOKUP_CREATE | KEY_LOOKUP_PARTIAL,
1084 if (IS_ERR(key_ref)) {
1085 ret = PTR_ERR(key_ref);
1089 key = key_ref_to_ptr(key_ref);
1091 /* make the changes with the locks held to prevent chown/chmod races */
1093 down_write(&key->sem);
1095 /* if we're not the sysadmin, we can only change a key that we own */
1096 if (uid_eq(key->uid, current_fsuid()) || capable(CAP_SYS_ADMIN)) {
1098 notify_key(key, NOTIFY_KEY_SETATTR, 0);
1102 up_write(&key->sem);
1109 * Get the destination keyring for instantiation and check that the caller has
1110 * Write permission on it.
1112 static long get_instantiation_keyring(key_serial_t ringid,
1113 struct request_key_auth *rka,
1114 struct key **_dest_keyring)
1118 *_dest_keyring = NULL;
1120 /* just return a NULL pointer if we weren't asked to make a link */
1124 /* if a specific keyring is nominated by ID, then use that */
1126 dkref = lookup_user_key(ringid, KEY_LOOKUP_CREATE, KEY_NEED_WRITE);
1128 return PTR_ERR(dkref);
1129 *_dest_keyring = key_ref_to_ptr(dkref);
1133 if (ringid == KEY_SPEC_REQKEY_AUTH_KEY)
1136 /* otherwise specify the destination keyring recorded in the
1137 * authorisation key (any KEY_SPEC_*_KEYRING) */
1138 if (ringid >= KEY_SPEC_REQUESTOR_KEYRING) {
1139 *_dest_keyring = key_get(rka->dest_keyring);
1147 * Change the request_key authorisation key on the current process.
1149 static int keyctl_change_reqkey_auth(struct key *key)
1153 new = prepare_creds();
1157 key_put(new->request_key_auth);
1158 new->request_key_auth = key_get(key);
1160 return commit_creds(new);
1164 * Instantiate a key with the specified payload and link the key into the
1165 * destination keyring if one is given.
1167 * The caller must have the appropriate instantiation permit set for this to
1168 * work (see keyctl_assume_authority). No other permissions are required.
1170 * If successful, 0 will be returned.
1172 static long keyctl_instantiate_key_common(key_serial_t id,
1173 struct iov_iter *from,
1174 key_serial_t ringid)
1176 const struct cred *cred = current_cred();
1177 struct request_key_auth *rka;
1178 struct key *instkey, *dest_keyring;
1179 size_t plen = from ? iov_iter_count(from) : 0;
1183 kenter("%d,,%zu,%d", id, plen, ringid);
1189 if (plen > 1024 * 1024 - 1)
1192 /* the appropriate instantiation authorisation key must have been
1193 * assumed before calling this */
1195 instkey = cred->request_key_auth;
1199 rka = instkey->payload.data[0];
1200 if (rka->target_key->serial != id)
1203 /* pull the payload in if one was supplied */
1208 payload = kvmalloc(plen, GFP_KERNEL);
1213 if (!copy_from_iter_full(payload, plen, from))
1217 /* find the destination keyring amongst those belonging to the
1218 * requesting task */
1219 ret = get_instantiation_keyring(ringid, rka, &dest_keyring);
1223 /* instantiate the key and link it into a keyring */
1224 ret = key_instantiate_and_link(rka->target_key, payload, plen,
1225 dest_keyring, instkey);
1227 key_put(dest_keyring);
1229 /* discard the assumed authority if it's just been disabled by
1230 * instantiation of the key */
1232 keyctl_change_reqkey_auth(NULL);
1235 kvfree_sensitive(payload, plen);
1241 * Instantiate a key with the specified payload and link the key into the
1242 * destination keyring if one is given.
1244 * The caller must have the appropriate instantiation permit set for this to
1245 * work (see keyctl_assume_authority). No other permissions are required.
1247 * If successful, 0 will be returned.
1249 long keyctl_instantiate_key(key_serial_t id,
1250 const void __user *_payload,
1252 key_serial_t ringid)
1254 if (_payload && plen) {
1255 struct iov_iter from;
1258 ret = import_ubuf(ITER_SOURCE, (void __user *)_payload, plen,
1263 return keyctl_instantiate_key_common(id, &from, ringid);
1266 return keyctl_instantiate_key_common(id, NULL, ringid);
1270 * Instantiate a key with the specified multipart payload and link the key into
1271 * the destination keyring if one is given.
1273 * The caller must have the appropriate instantiation permit set for this to
1274 * work (see keyctl_assume_authority). No other permissions are required.
1276 * If successful, 0 will be returned.
1278 long keyctl_instantiate_key_iov(key_serial_t id,
1279 const struct iovec __user *_payload_iov,
1281 key_serial_t ringid)
1283 struct iovec iovstack[UIO_FASTIOV], *iov = iovstack;
1284 struct iov_iter from;
1290 ret = import_iovec(ITER_SOURCE, _payload_iov, ioc,
1291 ARRAY_SIZE(iovstack), &iov, &from);
1294 ret = keyctl_instantiate_key_common(id, &from, ringid);
1300 * Negatively instantiate the key with the given timeout (in seconds) and link
1301 * the key into the destination keyring if one is given.
1303 * The caller must have the appropriate instantiation permit set for this to
1304 * work (see keyctl_assume_authority). No other permissions are required.
1306 * The key and any links to the key will be automatically garbage collected
1307 * after the timeout expires.
1309 * Negative keys are used to rate limit repeated request_key() calls by causing
1310 * them to return -ENOKEY until the negative key expires.
1312 * If successful, 0 will be returned.
1314 long keyctl_negate_key(key_serial_t id, unsigned timeout, key_serial_t ringid)
1316 return keyctl_reject_key(id, timeout, ENOKEY, ringid);
1320 * Negatively instantiate the key with the given timeout (in seconds) and error
1321 * code and link the key into the destination keyring if one is given.
1323 * The caller must have the appropriate instantiation permit set for this to
1324 * work (see keyctl_assume_authority). No other permissions are required.
1326 * The key and any links to the key will be automatically garbage collected
1327 * after the timeout expires.
1329 * Negative keys are used to rate limit repeated request_key() calls by causing
1330 * them to return the specified error code until the negative key expires.
1332 * If successful, 0 will be returned.
1334 long keyctl_reject_key(key_serial_t id, unsigned timeout, unsigned error,
1335 key_serial_t ringid)
1337 const struct cred *cred = current_cred();
1338 struct request_key_auth *rka;
1339 struct key *instkey, *dest_keyring;
1342 kenter("%d,%u,%u,%d", id, timeout, error, ringid);
1344 /* must be a valid error code and mustn't be a kernel special */
1346 error >= MAX_ERRNO ||
1347 error == ERESTARTSYS ||
1348 error == ERESTARTNOINTR ||
1349 error == ERESTARTNOHAND ||
1350 error == ERESTART_RESTARTBLOCK)
1353 /* the appropriate instantiation authorisation key must have been
1354 * assumed before calling this */
1356 instkey = cred->request_key_auth;
1360 rka = instkey->payload.data[0];
1361 if (rka->target_key->serial != id)
1364 /* find the destination keyring if present (which must also be
1366 ret = get_instantiation_keyring(ringid, rka, &dest_keyring);
1370 /* instantiate the key and link it into a keyring */
1371 ret = key_reject_and_link(rka->target_key, timeout, error,
1372 dest_keyring, instkey);
1374 key_put(dest_keyring);
1376 /* discard the assumed authority if it's just been disabled by
1377 * instantiation of the key */
1379 keyctl_change_reqkey_auth(NULL);
1386 * Read or set the default keyring in which request_key() will cache keys and
1387 * return the old setting.
1389 * If a thread or process keyring is specified then it will be created if it
1390 * doesn't yet exist. The old setting will be returned if successful.
1392 long keyctl_set_reqkey_keyring(int reqkey_defl)
1395 int ret, old_setting;
1397 old_setting = current_cred_xxx(jit_keyring);
1399 if (reqkey_defl == KEY_REQKEY_DEFL_NO_CHANGE)
1402 new = prepare_creds();
1406 switch (reqkey_defl) {
1407 case KEY_REQKEY_DEFL_THREAD_KEYRING:
1408 ret = install_thread_keyring_to_cred(new);
1413 case KEY_REQKEY_DEFL_PROCESS_KEYRING:
1414 ret = install_process_keyring_to_cred(new);
1419 case KEY_REQKEY_DEFL_DEFAULT:
1420 case KEY_REQKEY_DEFL_SESSION_KEYRING:
1421 case KEY_REQKEY_DEFL_USER_KEYRING:
1422 case KEY_REQKEY_DEFL_USER_SESSION_KEYRING:
1423 case KEY_REQKEY_DEFL_REQUESTOR_KEYRING:
1426 case KEY_REQKEY_DEFL_NO_CHANGE:
1427 case KEY_REQKEY_DEFL_GROUP_KEYRING:
1434 new->jit_keyring = reqkey_defl;
1443 * Set or clear the timeout on a key.
1445 * Either the key must grant the caller Setattr permission or else the caller
1446 * must hold an instantiation authorisation token for the key.
1448 * The timeout is either 0 to clear the timeout, or a number of seconds from
1449 * the current time. The key and any links to the key will be automatically
1450 * garbage collected after the timeout expires.
1452 * Keys with KEY_FLAG_KEEP set should not be timed out.
1454 * If successful, 0 is returned.
1456 long keyctl_set_timeout(key_serial_t id, unsigned timeout)
1458 struct key *key, *instkey;
1462 key_ref = lookup_user_key(id, KEY_LOOKUP_CREATE | KEY_LOOKUP_PARTIAL,
1464 if (IS_ERR(key_ref)) {
1465 /* setting the timeout on a key under construction is permitted
1466 * if we have the authorisation token handy */
1467 if (PTR_ERR(key_ref) == -EACCES) {
1468 instkey = key_get_instantiation_authkey(id);
1469 if (!IS_ERR(instkey)) {
1471 key_ref = lookup_user_key(id,
1473 KEY_AUTHTOKEN_OVERRIDE);
1474 if (!IS_ERR(key_ref))
1479 ret = PTR_ERR(key_ref);
1484 key = key_ref_to_ptr(key_ref);
1486 if (test_bit(KEY_FLAG_KEEP, &key->flags)) {
1489 key_set_timeout(key, timeout);
1490 notify_key(key, NOTIFY_KEY_SETATTR, 0);
1499 * Assume (or clear) the authority to instantiate the specified key.
1501 * This sets the authoritative token currently in force for key instantiation.
1502 * This must be done for a key to be instantiated. It has the effect of making
1503 * available all the keys from the caller of the request_key() that created a
1504 * key to request_key() calls made by the caller of this function.
1506 * The caller must have the instantiation key in their process keyrings with a
1507 * Search permission grant available to the caller.
1509 * If the ID given is 0, then the setting will be cleared and 0 returned.
1511 * If the ID given has a matching an authorisation key, then that key will be
1512 * set and its ID will be returned. The authorisation key can be read to get
1513 * the callout information passed to request_key().
1515 long keyctl_assume_authority(key_serial_t id)
1517 struct key *authkey;
1520 /* special key IDs aren't permitted */
1525 /* we divest ourselves of authority if given an ID of 0 */
1527 ret = keyctl_change_reqkey_auth(NULL);
1531 /* attempt to assume the authority temporarily granted to us whilst we
1532 * instantiate the specified key
1533 * - the authorisation key must be in the current task's keyrings
1536 authkey = key_get_instantiation_authkey(id);
1537 if (IS_ERR(authkey)) {
1538 ret = PTR_ERR(authkey);
1542 ret = keyctl_change_reqkey_auth(authkey);
1544 ret = authkey->serial;
1551 * Get a key's the LSM security label.
1553 * The key must grant the caller View permission for this to work.
1555 * If there's a buffer, then up to buflen bytes of data will be placed into it.
1557 * If successful, the amount of information available will be returned,
1558 * irrespective of how much was copied (including the terminal NUL).
1560 long keyctl_get_security(key_serial_t keyid,
1561 char __user *buffer,
1564 struct key *key, *instkey;
1569 key_ref = lookup_user_key(keyid, KEY_LOOKUP_PARTIAL, KEY_NEED_VIEW);
1570 if (IS_ERR(key_ref)) {
1571 if (PTR_ERR(key_ref) != -EACCES)
1572 return PTR_ERR(key_ref);
1574 /* viewing a key under construction is also permitted if we
1575 * have the authorisation token handy */
1576 instkey = key_get_instantiation_authkey(keyid);
1577 if (IS_ERR(instkey))
1578 return PTR_ERR(instkey);
1581 key_ref = lookup_user_key(keyid, KEY_LOOKUP_PARTIAL,
1582 KEY_AUTHTOKEN_OVERRIDE);
1583 if (IS_ERR(key_ref))
1584 return PTR_ERR(key_ref);
1587 key = key_ref_to_ptr(key_ref);
1588 ret = security_key_getsecurity(key, &context);
1590 /* if no information was returned, give userspace an empty
1593 if (buffer && buflen > 0 &&
1594 copy_to_user(buffer, "", 1) != 0)
1596 } else if (ret > 0) {
1597 /* return as much data as there's room for */
1598 if (buffer && buflen > 0) {
1602 if (copy_to_user(buffer, context, buflen) != 0)
1609 key_ref_put(key_ref);
1614 * Attempt to install the calling process's session keyring on the process's
1617 * The keyring must exist and must grant the caller LINK permission, and the
1618 * parent process must be single-threaded and must have the same effective
1619 * ownership as this process and mustn't be SUID/SGID.
1621 * The keyring will be emplaced on the parent when it next resumes userspace.
1623 * If successful, 0 will be returned.
1625 long keyctl_session_to_parent(void)
1627 struct task_struct *me, *parent;
1628 const struct cred *mycred, *pcred;
1629 struct callback_head *newwork, *oldwork;
1630 key_ref_t keyring_r;
1634 keyring_r = lookup_user_key(KEY_SPEC_SESSION_KEYRING, 0, KEY_NEED_LINK);
1635 if (IS_ERR(keyring_r))
1636 return PTR_ERR(keyring_r);
1640 /* our parent is going to need a new cred struct, a new tgcred struct
1641 * and new security data, so we allocate them here to prevent ENOMEM in
1643 cred = cred_alloc_blank();
1646 newwork = &cred->rcu;
1648 cred->session_keyring = key_ref_to_ptr(keyring_r);
1650 init_task_work(newwork, key_change_session_keyring);
1654 write_lock_irq(&tasklist_lock);
1658 parent = rcu_dereference_protected(me->real_parent,
1659 lockdep_is_held(&tasklist_lock));
1661 /* the parent mustn't be init and mustn't be a kernel thread */
1662 if (parent->pid <= 1 || !parent->mm)
1665 /* the parent must be single threaded */
1666 if (!thread_group_empty(parent))
1669 /* the parent and the child must have different session keyrings or
1670 * there's no point */
1671 mycred = current_cred();
1672 pcred = __task_cred(parent);
1673 if (mycred == pcred ||
1674 mycred->session_keyring == pcred->session_keyring) {
1679 /* the parent must have the same effective ownership and mustn't be
1681 if (!uid_eq(pcred->uid, mycred->euid) ||
1682 !uid_eq(pcred->euid, mycred->euid) ||
1683 !uid_eq(pcred->suid, mycred->euid) ||
1684 !gid_eq(pcred->gid, mycred->egid) ||
1685 !gid_eq(pcred->egid, mycred->egid) ||
1686 !gid_eq(pcred->sgid, mycred->egid))
1689 /* the keyrings must have the same UID */
1690 if ((pcred->session_keyring &&
1691 !uid_eq(pcred->session_keyring->uid, mycred->euid)) ||
1692 !uid_eq(mycred->session_keyring->uid, mycred->euid))
1695 /* cancel an already pending keyring replacement */
1696 oldwork = task_work_cancel(parent, key_change_session_keyring);
1698 /* the replacement session keyring is applied just prior to userspace
1700 ret = task_work_add(parent, newwork, TWA_RESUME);
1704 write_unlock_irq(&tasklist_lock);
1707 put_cred(container_of(oldwork, struct cred, rcu));
1713 key_ref_put(keyring_r);
1718 * Apply a restriction to a given keyring.
1720 * The caller must have Setattr permission to change keyring restrictions.
1722 * The requested type name may be a NULL pointer to reject all attempts
1723 * to link to the keyring. In this case, _restriction must also be NULL.
1724 * Otherwise, both _type and _restriction must be non-NULL.
1726 * Returns 0 if successful.
1728 long keyctl_restrict_keyring(key_serial_t id, const char __user *_type,
1729 const char __user *_restriction)
1733 char *restriction = NULL;
1736 key_ref = lookup_user_key(id, 0, KEY_NEED_SETATTR);
1737 if (IS_ERR(key_ref))
1738 return PTR_ERR(key_ref);
1745 ret = key_get_type_from_user(type, _type, sizeof(type));
1749 restriction = strndup_user(_restriction, PAGE_SIZE);
1750 if (IS_ERR(restriction)) {
1751 ret = PTR_ERR(restriction);
1759 ret = keyring_restrict(key_ref, _type ? type : NULL, restriction);
1762 key_ref_put(key_ref);
1766 #ifdef CONFIG_KEY_NOTIFICATIONS
1768 * Watch for changes to a key.
1770 * The caller must have View permission to watch a key or keyring.
1772 long keyctl_watch_key(key_serial_t id, int watch_queue_fd, int watch_id)
1774 struct watch_queue *wqueue;
1775 struct watch_list *wlist = NULL;
1776 struct watch *watch = NULL;
1781 if (watch_id < -1 || watch_id > 0xff)
1784 key_ref = lookup_user_key(id, KEY_LOOKUP_CREATE, KEY_NEED_VIEW);
1785 if (IS_ERR(key_ref))
1786 return PTR_ERR(key_ref);
1787 key = key_ref_to_ptr(key_ref);
1789 wqueue = get_watch_queue(watch_queue_fd);
1790 if (IS_ERR(wqueue)) {
1791 ret = PTR_ERR(wqueue);
1795 if (watch_id >= 0) {
1797 if (!key->watchers) {
1798 wlist = kzalloc(sizeof(*wlist), GFP_KERNEL);
1801 init_watch_list(wlist, NULL);
1804 watch = kzalloc(sizeof(*watch), GFP_KERNEL);
1808 init_watch(watch, wqueue);
1809 watch->id = key->serial;
1810 watch->info_id = (u32)watch_id << WATCH_INFO_ID__SHIFT;
1812 ret = security_watch_key(key);
1816 down_write(&key->sem);
1817 if (!key->watchers) {
1818 key->watchers = wlist;
1822 ret = add_watch_to_object(watch, key->watchers);
1823 up_write(&key->sem);
1829 if (key->watchers) {
1830 down_write(&key->sem);
1831 ret = remove_watch_from_object(key->watchers,
1832 wqueue, key_serial(key),
1834 up_write(&key->sem);
1843 put_watch_queue(wqueue);
1848 #endif /* CONFIG_KEY_NOTIFICATIONS */
1851 * Get keyrings subsystem capabilities.
1853 long keyctl_capabilities(unsigned char __user *_buffer, size_t buflen)
1855 size_t size = buflen;
1858 if (size > sizeof(keyrings_capabilities))
1859 size = sizeof(keyrings_capabilities);
1860 if (copy_to_user(_buffer, keyrings_capabilities, size) != 0)
1862 if (size < buflen &&
1863 clear_user(_buffer + size, buflen - size) != 0)
1867 return sizeof(keyrings_capabilities);
1871 * The key control system call
1873 SYSCALL_DEFINE5(keyctl, int, option, unsigned long, arg2, unsigned long, arg3,
1874 unsigned long, arg4, unsigned long, arg5)
1877 case KEYCTL_GET_KEYRING_ID:
1878 return keyctl_get_keyring_ID((key_serial_t) arg2,
1881 case KEYCTL_JOIN_SESSION_KEYRING:
1882 return keyctl_join_session_keyring((const char __user *) arg2);
1885 return keyctl_update_key((key_serial_t) arg2,
1886 (const void __user *) arg3,
1890 return keyctl_revoke_key((key_serial_t) arg2);
1892 case KEYCTL_DESCRIBE:
1893 return keyctl_describe_key((key_serial_t) arg2,
1894 (char __user *) arg3,
1898 return keyctl_keyring_clear((key_serial_t) arg2);
1901 return keyctl_keyring_link((key_serial_t) arg2,
1902 (key_serial_t) arg3);
1905 return keyctl_keyring_unlink((key_serial_t) arg2,
1906 (key_serial_t) arg3);
1909 return keyctl_keyring_search((key_serial_t) arg2,
1910 (const char __user *) arg3,
1911 (const char __user *) arg4,
1912 (key_serial_t) arg5);
1915 return keyctl_read_key((key_serial_t) arg2,
1916 (char __user *) arg3,
1920 return keyctl_chown_key((key_serial_t) arg2,
1924 case KEYCTL_SETPERM:
1925 return keyctl_setperm_key((key_serial_t) arg2,
1928 case KEYCTL_INSTANTIATE:
1929 return keyctl_instantiate_key((key_serial_t) arg2,
1930 (const void __user *) arg3,
1932 (key_serial_t) arg5);
1935 return keyctl_negate_key((key_serial_t) arg2,
1937 (key_serial_t) arg4);
1939 case KEYCTL_SET_REQKEY_KEYRING:
1940 return keyctl_set_reqkey_keyring(arg2);
1942 case KEYCTL_SET_TIMEOUT:
1943 return keyctl_set_timeout((key_serial_t) arg2,
1946 case KEYCTL_ASSUME_AUTHORITY:
1947 return keyctl_assume_authority((key_serial_t) arg2);
1949 case KEYCTL_GET_SECURITY:
1950 return keyctl_get_security((key_serial_t) arg2,
1951 (char __user *) arg3,
1954 case KEYCTL_SESSION_TO_PARENT:
1955 return keyctl_session_to_parent();
1958 return keyctl_reject_key((key_serial_t) arg2,
1961 (key_serial_t) arg5);
1963 case KEYCTL_INSTANTIATE_IOV:
1964 return keyctl_instantiate_key_iov(
1965 (key_serial_t) arg2,
1966 (const struct iovec __user *) arg3,
1968 (key_serial_t) arg5);
1970 case KEYCTL_INVALIDATE:
1971 return keyctl_invalidate_key((key_serial_t) arg2);
1973 case KEYCTL_GET_PERSISTENT:
1974 return keyctl_get_persistent((uid_t)arg2, (key_serial_t)arg3);
1976 case KEYCTL_DH_COMPUTE:
1977 return keyctl_dh_compute((struct keyctl_dh_params __user *) arg2,
1978 (char __user *) arg3, (size_t) arg4,
1979 (struct keyctl_kdf_params __user *) arg5);
1981 case KEYCTL_RESTRICT_KEYRING:
1982 return keyctl_restrict_keyring((key_serial_t) arg2,
1983 (const char __user *) arg3,
1984 (const char __user *) arg4);
1986 case KEYCTL_PKEY_QUERY:
1989 return keyctl_pkey_query((key_serial_t)arg2,
1990 (const char __user *)arg4,
1991 (struct keyctl_pkey_query __user *)arg5);
1993 case KEYCTL_PKEY_ENCRYPT:
1994 case KEYCTL_PKEY_DECRYPT:
1995 case KEYCTL_PKEY_SIGN:
1996 return keyctl_pkey_e_d_s(
1998 (const struct keyctl_pkey_params __user *)arg2,
1999 (const char __user *)arg3,
2000 (const void __user *)arg4,
2001 (void __user *)arg5);
2003 case KEYCTL_PKEY_VERIFY:
2004 return keyctl_pkey_verify(
2005 (const struct keyctl_pkey_params __user *)arg2,
2006 (const char __user *)arg3,
2007 (const void __user *)arg4,
2008 (const void __user *)arg5);
2011 return keyctl_keyring_move((key_serial_t)arg2,
2014 (unsigned int)arg5);
2016 case KEYCTL_CAPABILITIES:
2017 return keyctl_capabilities((unsigned char __user *)arg2, (size_t)arg3);
2019 case KEYCTL_WATCH_KEY:
2020 return keyctl_watch_key((key_serial_t)arg2, (int)arg3, (int)arg4);