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/sched/task.h>
16 #include <linux/slab.h>
17 #include <linux/syscalls.h>
18 #include <linux/key.h>
19 #include <linux/keyctl.h>
21 #include <linux/capability.h>
22 #include <linux/cred.h>
23 #include <linux/string.h>
24 #include <linux/err.h>
25 #include <linux/vmalloc.h>
26 #include <linux/security.h>
27 #include <linux/uio.h>
28 #include <linux/uaccess.h>
29 #include <keys/request_key_auth-type.h>
32 #define KEY_MAX_DESC_SIZE 4096
34 static int key_get_type_from_user(char *type,
35 const char __user *_type,
40 ret = strncpy_from_user(type, _type, len);
43 if (ret == 0 || ret >= len)
52 * Extract the description of a new key from userspace and either add it as a
53 * new key to the specified keyring or update a matching key in that keyring.
55 * If the description is NULL or an empty string, the key type is asked to
56 * generate one from the payload.
58 * The keyring must be writable so that we can attach the key to it.
60 * If successful, the new key's serial number is returned, otherwise an error
63 SYSCALL_DEFINE5(add_key, const char __user *, _type,
64 const char __user *, _description,
65 const void __user *, _payload,
69 key_ref_t keyring_ref, key_ref;
70 char type[32], *description;
75 if (plen > 1024 * 1024 - 1)
78 /* draw all the data into kernel space */
79 ret = key_get_type_from_user(type, _type, sizeof(type));
85 description = strndup_user(_description, KEY_MAX_DESC_SIZE);
86 if (IS_ERR(description)) {
87 ret = PTR_ERR(description);
93 } else if ((description[0] == '.') &&
94 (strncmp(type, "keyring", 7) == 0)) {
100 /* pull the payload in if one was supplied */
105 payload = kvmalloc(plen, GFP_KERNEL);
110 if (copy_from_user(payload, _payload, plen) != 0)
114 /* find the target keyring (which must be writable) */
115 keyring_ref = lookup_user_key(ringid, KEY_LOOKUP_CREATE, KEY_NEED_WRITE);
116 if (IS_ERR(keyring_ref)) {
117 ret = PTR_ERR(keyring_ref);
121 /* create or update the requested key and add it to the target
123 key_ref = key_create_or_update(keyring_ref, type, description,
124 payload, plen, KEY_PERM_UNDEF,
126 if (!IS_ERR(key_ref)) {
127 ret = key_ref_to_ptr(key_ref)->serial;
128 key_ref_put(key_ref);
131 ret = PTR_ERR(key_ref);
134 key_ref_put(keyring_ref);
136 kvfree_sensitive(payload, plen);
144 * Search the process keyrings and keyring trees linked from those for a
145 * matching key. Keyrings must have appropriate Search permission to be
148 * If a key is found, it will be attached to the destination keyring if there's
149 * one specified and the serial number of the key will be returned.
151 * If no key is found, /sbin/request-key will be invoked if _callout_info is
152 * non-NULL in an attempt to create a key. The _callout_info string will be
153 * passed to /sbin/request-key to aid with completing the request. If the
154 * _callout_info string is "" then it will be changed to "-".
156 SYSCALL_DEFINE4(request_key, const char __user *, _type,
157 const char __user *, _description,
158 const char __user *, _callout_info,
159 key_serial_t, destringid)
161 struct key_type *ktype;
165 char type[32], *description, *callout_info;
168 /* pull the type into kernel space */
169 ret = key_get_type_from_user(type, _type, sizeof(type));
173 /* pull the description into kernel space */
174 description = strndup_user(_description, KEY_MAX_DESC_SIZE);
175 if (IS_ERR(description)) {
176 ret = PTR_ERR(description);
180 /* pull the callout info into kernel space */
184 callout_info = strndup_user(_callout_info, PAGE_SIZE);
185 if (IS_ERR(callout_info)) {
186 ret = PTR_ERR(callout_info);
189 callout_len = strlen(callout_info);
192 /* get the destination keyring if specified */
195 dest_ref = lookup_user_key(destringid, KEY_LOOKUP_CREATE,
197 if (IS_ERR(dest_ref)) {
198 ret = PTR_ERR(dest_ref);
203 /* find the key type */
204 ktype = key_type_lookup(type);
206 ret = PTR_ERR(ktype);
211 key = request_key_and_link(ktype, description, callout_info,
212 callout_len, NULL, key_ref_to_ptr(dest_ref),
219 /* wait for the key to finish being constructed */
220 ret = wait_for_key_construction(key, 1);
231 key_ref_put(dest_ref);
241 * Get the ID of the specified process keyring.
243 * The requested keyring must have search permission to be found.
245 * If successful, the ID of the requested keyring will be returned.
247 long keyctl_get_keyring_ID(key_serial_t id, int create)
250 unsigned long lflags;
253 lflags = create ? KEY_LOOKUP_CREATE : 0;
254 key_ref = lookup_user_key(id, lflags, KEY_NEED_SEARCH);
255 if (IS_ERR(key_ref)) {
256 ret = PTR_ERR(key_ref);
260 ret = key_ref_to_ptr(key_ref)->serial;
261 key_ref_put(key_ref);
267 * Join a (named) session keyring.
269 * Create and join an anonymous session keyring or join a named session
270 * keyring, creating it if necessary. A named session keyring must have Search
271 * permission for it to be joined. Session keyrings without this permit will
272 * be skipped over. It is not permitted for userspace to create or join
273 * keyrings whose name begin with a dot.
275 * If successful, the ID of the joined session keyring will be returned.
277 long keyctl_join_session_keyring(const char __user *_name)
282 /* fetch the name from userspace */
285 name = strndup_user(_name, KEY_MAX_DESC_SIZE);
296 /* join the session */
297 ret = join_session_keyring(name);
305 * Update a key's data payload from the given data.
307 * The key must grant the caller Write permission and the key type must support
308 * updating for this to work. A negative key can be positively instantiated
311 * If successful, 0 will be returned. If the key type does not support
312 * updating, then -EOPNOTSUPP will be returned.
314 long keyctl_update_key(key_serial_t id,
315 const void __user *_payload,
323 if (plen > PAGE_SIZE)
326 /* pull the payload in if one was supplied */
330 payload = kvmalloc(plen, GFP_KERNEL);
335 if (copy_from_user(payload, _payload, plen) != 0)
339 /* find the target key (which must be writable) */
340 key_ref = lookup_user_key(id, 0, KEY_NEED_WRITE);
341 if (IS_ERR(key_ref)) {
342 ret = PTR_ERR(key_ref);
347 ret = key_update(key_ref, payload, plen);
349 key_ref_put(key_ref);
351 kvfree_sensitive(payload, plen);
359 * The key must be grant the caller Write or Setattr permission for this to
360 * work. The key type should give up its quota claim when revoked. The key
361 * and any links to the key will be automatically garbage collected after a
362 * certain amount of time (/proc/sys/kernel/keys/gc_delay).
364 * Keys with KEY_FLAG_KEEP set should not be revoked.
366 * If successful, 0 is returned.
368 long keyctl_revoke_key(key_serial_t id)
374 key_ref = lookup_user_key(id, 0, KEY_NEED_WRITE);
375 if (IS_ERR(key_ref)) {
376 ret = PTR_ERR(key_ref);
379 key_ref = lookup_user_key(id, 0, KEY_NEED_SETATTR);
380 if (IS_ERR(key_ref)) {
381 ret = PTR_ERR(key_ref);
386 key = key_ref_to_ptr(key_ref);
388 if (test_bit(KEY_FLAG_KEEP, &key->flags))
393 key_ref_put(key_ref);
401 * The key must be grant the caller Invalidate permission for this to work.
402 * The key and any links to the key will be automatically garbage collected
405 * Keys with KEY_FLAG_KEEP set should not be invalidated.
407 * If successful, 0 is returned.
409 long keyctl_invalidate_key(key_serial_t id)
417 key_ref = lookup_user_key(id, 0, KEY_NEED_SEARCH);
418 if (IS_ERR(key_ref)) {
419 ret = PTR_ERR(key_ref);
421 /* Root is permitted to invalidate certain special keys */
422 if (capable(CAP_SYS_ADMIN)) {
423 key_ref = lookup_user_key(id, 0, 0);
426 if (test_bit(KEY_FLAG_ROOT_CAN_INVAL,
427 &key_ref_to_ptr(key_ref)->flags))
436 key = key_ref_to_ptr(key_ref);
438 if (test_bit(KEY_FLAG_KEEP, &key->flags))
443 key_ref_put(key_ref);
445 kleave(" = %ld", ret);
450 * Clear the specified keyring, creating an empty process keyring if one of the
451 * special keyring IDs is used.
453 * The keyring must grant the caller Write permission and not have
454 * KEY_FLAG_KEEP set for this to work. If successful, 0 will be returned.
456 long keyctl_keyring_clear(key_serial_t ringid)
458 key_ref_t keyring_ref;
462 keyring_ref = lookup_user_key(ringid, KEY_LOOKUP_CREATE, KEY_NEED_WRITE);
463 if (IS_ERR(keyring_ref)) {
464 ret = PTR_ERR(keyring_ref);
466 /* Root is permitted to invalidate certain special keyrings */
467 if (capable(CAP_SYS_ADMIN)) {
468 keyring_ref = lookup_user_key(ringid, 0, 0);
469 if (IS_ERR(keyring_ref))
471 if (test_bit(KEY_FLAG_ROOT_CAN_CLEAR,
472 &key_ref_to_ptr(keyring_ref)->flags))
481 keyring = key_ref_to_ptr(keyring_ref);
482 if (test_bit(KEY_FLAG_KEEP, &keyring->flags))
485 ret = keyring_clear(keyring);
487 key_ref_put(keyring_ref);
493 * Create a link from a keyring to a key if there's no matching key in the
494 * keyring, otherwise replace the link to the matching key with a link to the
497 * The key must grant the caller Link permission and the the keyring must grant
498 * the caller Write permission. Furthermore, if an additional link is created,
499 * the keyring's quota will be extended.
501 * If successful, 0 will be returned.
503 long keyctl_keyring_link(key_serial_t id, key_serial_t ringid)
505 key_ref_t keyring_ref, key_ref;
508 keyring_ref = lookup_user_key(ringid, KEY_LOOKUP_CREATE, KEY_NEED_WRITE);
509 if (IS_ERR(keyring_ref)) {
510 ret = PTR_ERR(keyring_ref);
514 key_ref = lookup_user_key(id, KEY_LOOKUP_CREATE, KEY_NEED_LINK);
515 if (IS_ERR(key_ref)) {
516 ret = PTR_ERR(key_ref);
520 ret = key_link(key_ref_to_ptr(keyring_ref), key_ref_to_ptr(key_ref));
522 key_ref_put(key_ref);
524 key_ref_put(keyring_ref);
530 * Unlink a key from a keyring.
532 * The keyring must grant the caller Write permission for this to work; the key
533 * itself need not grant the caller anything. If the last link to a key is
534 * removed then that key will be scheduled for destruction.
536 * Keys or keyrings with KEY_FLAG_KEEP set should not be unlinked.
538 * If successful, 0 will be returned.
540 long keyctl_keyring_unlink(key_serial_t id, key_serial_t ringid)
542 key_ref_t keyring_ref, key_ref;
543 struct key *keyring, *key;
546 keyring_ref = lookup_user_key(ringid, 0, KEY_NEED_WRITE);
547 if (IS_ERR(keyring_ref)) {
548 ret = PTR_ERR(keyring_ref);
552 key_ref = lookup_user_key(id, KEY_LOOKUP_FOR_UNLINK, 0);
553 if (IS_ERR(key_ref)) {
554 ret = PTR_ERR(key_ref);
558 keyring = key_ref_to_ptr(keyring_ref);
559 key = key_ref_to_ptr(key_ref);
560 if (test_bit(KEY_FLAG_KEEP, &keyring->flags) &&
561 test_bit(KEY_FLAG_KEEP, &key->flags))
564 ret = key_unlink(keyring, key);
566 key_ref_put(key_ref);
568 key_ref_put(keyring_ref);
574 * Return a description of a key to userspace.
576 * The key must grant the caller View permission for this to work.
578 * If there's a buffer, we place up to buflen bytes of data into it formatted
579 * in the following way:
581 * type;uid;gid;perm;description<NUL>
583 * If successful, we return the amount of description available, irrespective
584 * of how much we may have copied into the buffer.
586 long keyctl_describe_key(key_serial_t keyid,
590 struct key *key, *instkey;
594 int desclen, infolen;
596 key_ref = lookup_user_key(keyid, KEY_LOOKUP_PARTIAL, KEY_NEED_VIEW);
597 if (IS_ERR(key_ref)) {
598 /* viewing a key under construction is permitted if we have the
599 * authorisation token handy */
600 if (PTR_ERR(key_ref) == -EACCES) {
601 instkey = key_get_instantiation_authkey(keyid);
602 if (!IS_ERR(instkey)) {
604 key_ref = lookup_user_key(keyid,
607 if (!IS_ERR(key_ref))
612 ret = PTR_ERR(key_ref);
617 key = key_ref_to_ptr(key_ref);
618 desclen = strlen(key->description);
620 /* calculate how much information we're going to return */
622 infobuf = kasprintf(GFP_KERNEL,
625 from_kuid_munged(current_user_ns(), key->uid),
626 from_kgid_munged(current_user_ns(), key->gid),
630 infolen = strlen(infobuf);
631 ret = infolen + desclen + 1;
633 /* consider returning the data */
634 if (buffer && buflen >= ret) {
635 if (copy_to_user(buffer, infobuf, infolen) != 0 ||
636 copy_to_user(buffer + infolen, key->description,
643 key_ref_put(key_ref);
649 * Search the specified keyring and any keyrings it links to for a matching
650 * key. Only keyrings that grant the caller Search permission will be searched
651 * (this includes the starting keyring). Only keys with Search permission can
654 * If successful, the found key will be linked to the destination keyring if
655 * supplied and the key has Link permission, and the found key ID will be
658 long keyctl_keyring_search(key_serial_t ringid,
659 const char __user *_type,
660 const char __user *_description,
661 key_serial_t destringid)
663 struct key_type *ktype;
664 key_ref_t keyring_ref, key_ref, dest_ref;
665 char type[32], *description;
668 /* pull the type and description into kernel space */
669 ret = key_get_type_from_user(type, _type, sizeof(type));
673 description = strndup_user(_description, KEY_MAX_DESC_SIZE);
674 if (IS_ERR(description)) {
675 ret = PTR_ERR(description);
679 /* get the keyring at which to begin the search */
680 keyring_ref = lookup_user_key(ringid, 0, KEY_NEED_SEARCH);
681 if (IS_ERR(keyring_ref)) {
682 ret = PTR_ERR(keyring_ref);
686 /* get the destination keyring if specified */
689 dest_ref = lookup_user_key(destringid, KEY_LOOKUP_CREATE,
691 if (IS_ERR(dest_ref)) {
692 ret = PTR_ERR(dest_ref);
697 /* find the key type */
698 ktype = key_type_lookup(type);
700 ret = PTR_ERR(ktype);
705 key_ref = keyring_search(keyring_ref, ktype, description);
706 if (IS_ERR(key_ref)) {
707 ret = PTR_ERR(key_ref);
709 /* treat lack or presence of a negative key the same */
715 /* link the resulting key to the destination keyring if we can */
717 ret = key_permission(key_ref, KEY_NEED_LINK);
721 ret = key_link(key_ref_to_ptr(dest_ref), key_ref_to_ptr(key_ref));
726 ret = key_ref_to_ptr(key_ref)->serial;
729 key_ref_put(key_ref);
733 key_ref_put(dest_ref);
735 key_ref_put(keyring_ref);
743 * Call the read method
745 static long __keyctl_read_key(struct key *key, char *buffer, size_t buflen)
749 down_read(&key->sem);
750 ret = key_validate(key);
752 ret = key->type->read(key, buffer, buflen);
758 * Read a key's payload.
760 * The key must either grant the caller Read permission, or it must grant the
761 * caller Search permission when searched for from the process keyrings.
763 * If successful, we place up to buflen bytes of data into the buffer, if one
764 * is provided, and return the amount of data that is available in the key,
765 * irrespective of how much we copied into the buffer.
767 long keyctl_read_key(key_serial_t keyid, char __user *buffer, size_t buflen)
772 char *key_data = NULL;
775 /* find the key first */
776 key_ref = lookup_user_key(keyid, 0, 0);
777 if (IS_ERR(key_ref)) {
782 key = key_ref_to_ptr(key_ref);
784 ret = key_read_state(key);
786 goto key_put_out; /* Negatively instantiated */
788 /* see if we can read it directly */
789 ret = key_permission(key_ref, KEY_NEED_READ);
795 /* we can't; see if it's searchable from this process's keyrings
796 * - we automatically take account of the fact that it may be
797 * dangling off an instantiation key
799 if (!is_key_possessed(key_ref)) {
804 /* the key is probably readable - now try to read it */
806 if (!key->type->read) {
811 if (!buffer || !buflen) {
812 /* Get the key length from the read method */
813 ret = __keyctl_read_key(key, NULL, 0);
818 * Read the data with the semaphore held (since we might sleep)
819 * to protect against the key being updated or revoked.
821 * Allocating a temporary buffer to hold the keys before
822 * transferring them to user buffer to avoid potential
823 * deadlock involving page fault and mmap_sem.
825 * key_data_len = (buflen <= PAGE_SIZE)
826 * ? buflen : actual length of key data
828 * This prevents allocating arbitrary large buffer which can
829 * be much larger than the actual key length. In the latter case,
830 * at least 2 passes of this loop is required.
832 key_data_len = (buflen <= PAGE_SIZE) ? buflen : 0;
835 key_data = kvmalloc(key_data_len, GFP_KERNEL);
842 ret = __keyctl_read_key(key, key_data, key_data_len);
845 * Read methods will just return the required length without
846 * any copying if the provided length isn't large enough.
848 if (ret <= 0 || ret > buflen)
852 * The key may change (unlikely) in between 2 consecutive
853 * __keyctl_read_key() calls. In this case, we reallocate
854 * a larger buffer and redo the key read when
855 * key_data_len < ret <= buflen.
857 if (ret > key_data_len) {
858 if (unlikely(key_data))
859 kvfree_sensitive(key_data, key_data_len);
861 continue; /* Allocate buffer */
864 if (copy_to_user(buffer, key_data, ret))
868 kvfree_sensitive(key_data, key_data_len);
877 * Change the ownership of a key
879 * The key must grant the caller Setattr permission for this to work, though
880 * the key need not be fully instantiated yet. For the UID to be changed, or
881 * for the GID to be changed to a group the caller is not a member of, the
882 * caller must have sysadmin capability. If either uid or gid is -1 then that
883 * attribute is not changed.
885 * If the UID is to be changed, the new user must have sufficient quota to
886 * accept the key. The quota deduction will be removed from the old user to
887 * the new user should the attribute be changed.
889 * If successful, 0 will be returned.
891 long keyctl_chown_key(key_serial_t id, uid_t user, gid_t group)
893 struct key_user *newowner, *zapowner = NULL;
900 uid = make_kuid(current_user_ns(), user);
901 gid = make_kgid(current_user_ns(), group);
903 if ((user != (uid_t) -1) && !uid_valid(uid))
905 if ((group != (gid_t) -1) && !gid_valid(gid))
909 if (user == (uid_t) -1 && group == (gid_t) -1)
912 key_ref = lookup_user_key(id, KEY_LOOKUP_CREATE | KEY_LOOKUP_PARTIAL,
914 if (IS_ERR(key_ref)) {
915 ret = PTR_ERR(key_ref);
919 key = key_ref_to_ptr(key_ref);
921 /* make the changes with the locks held to prevent chown/chown races */
923 down_write(&key->sem);
926 bool is_privileged_op = false;
928 /* only the sysadmin can chown a key to some other UID */
929 if (user != (uid_t) -1 && !uid_eq(key->uid, uid))
930 is_privileged_op = true;
932 /* only the sysadmin can set the key's GID to a group other
933 * than one of those that the current process subscribes to */
934 if (group != (gid_t) -1 && !gid_eq(gid, key->gid) && !in_group_p(gid))
935 is_privileged_op = true;
937 if (is_privileged_op && !capable(CAP_SYS_ADMIN))
942 if (user != (uid_t) -1 && !uid_eq(uid, key->uid)) {
944 newowner = key_user_lookup(uid);
948 /* transfer the quota burden to the new user */
949 if (test_bit(KEY_FLAG_IN_QUOTA, &key->flags)) {
950 unsigned maxkeys = uid_eq(uid, GLOBAL_ROOT_UID) ?
951 key_quota_root_maxkeys : key_quota_maxkeys;
952 unsigned maxbytes = uid_eq(uid, GLOBAL_ROOT_UID) ?
953 key_quota_root_maxbytes : key_quota_maxbytes;
955 spin_lock(&newowner->lock);
956 if (newowner->qnkeys + 1 > maxkeys ||
957 newowner->qnbytes + key->quotalen > maxbytes ||
958 newowner->qnbytes + key->quotalen <
963 newowner->qnbytes += key->quotalen;
964 spin_unlock(&newowner->lock);
966 spin_lock(&key->user->lock);
968 key->user->qnbytes -= key->quotalen;
969 spin_unlock(&key->user->lock);
972 atomic_dec(&key->user->nkeys);
973 atomic_inc(&newowner->nkeys);
975 if (key->state != KEY_IS_UNINSTANTIATED) {
976 atomic_dec(&key->user->nikeys);
977 atomic_inc(&newowner->nikeys);
980 zapowner = key->user;
981 key->user = newowner;
986 if (group != (gid_t) -1)
995 key_user_put(zapowner);
1000 spin_unlock(&newowner->lock);
1001 zapowner = newowner;
1007 * Change the permission mask on a key.
1009 * The key must grant the caller Setattr permission for this to work, though
1010 * the key need not be fully instantiated yet. If the caller does not have
1011 * sysadmin capability, it may only change the permission on keys that it owns.
1013 long keyctl_setperm_key(key_serial_t id, key_perm_t perm)
1020 if (perm & ~(KEY_POS_ALL | KEY_USR_ALL | KEY_GRP_ALL | KEY_OTH_ALL))
1023 key_ref = lookup_user_key(id, KEY_LOOKUP_CREATE | KEY_LOOKUP_PARTIAL,
1025 if (IS_ERR(key_ref)) {
1026 ret = PTR_ERR(key_ref);
1030 key = key_ref_to_ptr(key_ref);
1032 /* make the changes with the locks held to prevent chown/chmod races */
1034 down_write(&key->sem);
1036 /* if we're not the sysadmin, we can only change a key that we own */
1037 if (uid_eq(key->uid, current_fsuid()) || capable(CAP_SYS_ADMIN)) {
1042 up_write(&key->sem);
1049 * Get the destination keyring for instantiation and check that the caller has
1050 * Write permission on it.
1052 static long get_instantiation_keyring(key_serial_t ringid,
1053 struct request_key_auth *rka,
1054 struct key **_dest_keyring)
1058 *_dest_keyring = NULL;
1060 /* just return a NULL pointer if we weren't asked to make a link */
1064 /* if a specific keyring is nominated by ID, then use that */
1066 dkref = lookup_user_key(ringid, KEY_LOOKUP_CREATE, KEY_NEED_WRITE);
1068 return PTR_ERR(dkref);
1069 *_dest_keyring = key_ref_to_ptr(dkref);
1073 if (ringid == KEY_SPEC_REQKEY_AUTH_KEY)
1076 /* otherwise specify the destination keyring recorded in the
1077 * authorisation key (any KEY_SPEC_*_KEYRING) */
1078 if (ringid >= KEY_SPEC_REQUESTOR_KEYRING) {
1079 *_dest_keyring = key_get(rka->dest_keyring);
1087 * Change the request_key authorisation key on the current process.
1089 static int keyctl_change_reqkey_auth(struct key *key)
1093 new = prepare_creds();
1097 key_put(new->request_key_auth);
1098 new->request_key_auth = key_get(key);
1100 return commit_creds(new);
1104 * Instantiate a key with the specified payload and link the key into the
1105 * destination keyring if one is given.
1107 * The caller must have the appropriate instantiation permit set for this to
1108 * work (see keyctl_assume_authority). No other permissions are required.
1110 * If successful, 0 will be returned.
1112 long keyctl_instantiate_key_common(key_serial_t id,
1113 struct iov_iter *from,
1114 key_serial_t ringid)
1116 const struct cred *cred = current_cred();
1117 struct request_key_auth *rka;
1118 struct key *instkey, *dest_keyring;
1119 size_t plen = from ? iov_iter_count(from) : 0;
1123 kenter("%d,,%zu,%d", id, plen, ringid);
1129 if (plen > 1024 * 1024 - 1)
1132 /* the appropriate instantiation authorisation key must have been
1133 * assumed before calling this */
1135 instkey = cred->request_key_auth;
1139 rka = instkey->payload.data[0];
1140 if (rka->target_key->serial != id)
1143 /* pull the payload in if one was supplied */
1148 payload = kvmalloc(plen, GFP_KERNEL);
1153 if (!copy_from_iter_full(payload, plen, from))
1157 /* find the destination keyring amongst those belonging to the
1158 * requesting task */
1159 ret = get_instantiation_keyring(ringid, rka, &dest_keyring);
1163 /* instantiate the key and link it into a keyring */
1164 ret = key_instantiate_and_link(rka->target_key, payload, plen,
1165 dest_keyring, instkey);
1167 key_put(dest_keyring);
1169 /* discard the assumed authority if it's just been disabled by
1170 * instantiation of the key */
1172 keyctl_change_reqkey_auth(NULL);
1175 kvfree_sensitive(payload, plen);
1181 * Instantiate a key with the specified payload and link the key into the
1182 * destination keyring if one is given.
1184 * The caller must have the appropriate instantiation permit set for this to
1185 * work (see keyctl_assume_authority). No other permissions are required.
1187 * If successful, 0 will be returned.
1189 long keyctl_instantiate_key(key_serial_t id,
1190 const void __user *_payload,
1192 key_serial_t ringid)
1194 if (_payload && plen) {
1196 struct iov_iter from;
1199 ret = import_single_range(WRITE, (void __user *)_payload, plen,
1204 return keyctl_instantiate_key_common(id, &from, ringid);
1207 return keyctl_instantiate_key_common(id, NULL, ringid);
1211 * Instantiate a key with the specified multipart payload and link the key into
1212 * the destination keyring if one is given.
1214 * The caller must have the appropriate instantiation permit set for this to
1215 * work (see keyctl_assume_authority). No other permissions are required.
1217 * If successful, 0 will be returned.
1219 long keyctl_instantiate_key_iov(key_serial_t id,
1220 const struct iovec __user *_payload_iov,
1222 key_serial_t ringid)
1224 struct iovec iovstack[UIO_FASTIOV], *iov = iovstack;
1225 struct iov_iter from;
1231 ret = import_iovec(WRITE, _payload_iov, ioc,
1232 ARRAY_SIZE(iovstack), &iov, &from);
1235 ret = keyctl_instantiate_key_common(id, &from, ringid);
1241 * Negatively instantiate the key with the given timeout (in seconds) and link
1242 * the key into the 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 * The key and any links to the key will be automatically garbage collected
1248 * after the timeout expires.
1250 * Negative keys are used to rate limit repeated request_key() calls by causing
1251 * them to return -ENOKEY until the negative key expires.
1253 * If successful, 0 will be returned.
1255 long keyctl_negate_key(key_serial_t id, unsigned timeout, key_serial_t ringid)
1257 return keyctl_reject_key(id, timeout, ENOKEY, ringid);
1261 * Negatively instantiate the key with the given timeout (in seconds) and error
1262 * code and link the key into the destination keyring if one is given.
1264 * The caller must have the appropriate instantiation permit set for this to
1265 * work (see keyctl_assume_authority). No other permissions are required.
1267 * The key and any links to the key will be automatically garbage collected
1268 * after the timeout expires.
1270 * Negative keys are used to rate limit repeated request_key() calls by causing
1271 * them to return the specified error code until the negative key expires.
1273 * If successful, 0 will be returned.
1275 long keyctl_reject_key(key_serial_t id, unsigned timeout, unsigned error,
1276 key_serial_t ringid)
1278 const struct cred *cred = current_cred();
1279 struct request_key_auth *rka;
1280 struct key *instkey, *dest_keyring;
1283 kenter("%d,%u,%u,%d", id, timeout, error, ringid);
1285 /* must be a valid error code and mustn't be a kernel special */
1287 error >= MAX_ERRNO ||
1288 error == ERESTARTSYS ||
1289 error == ERESTARTNOINTR ||
1290 error == ERESTARTNOHAND ||
1291 error == ERESTART_RESTARTBLOCK)
1294 /* the appropriate instantiation authorisation key must have been
1295 * assumed before calling this */
1297 instkey = cred->request_key_auth;
1301 rka = instkey->payload.data[0];
1302 if (rka->target_key->serial != id)
1305 /* find the destination keyring if present (which must also be
1307 ret = get_instantiation_keyring(ringid, rka, &dest_keyring);
1311 /* instantiate the key and link it into a keyring */
1312 ret = key_reject_and_link(rka->target_key, timeout, error,
1313 dest_keyring, instkey);
1315 key_put(dest_keyring);
1317 /* discard the assumed authority if it's just been disabled by
1318 * instantiation of the key */
1320 keyctl_change_reqkey_auth(NULL);
1327 * Read or set the default keyring in which request_key() will cache keys and
1328 * return the old setting.
1330 * If a thread or process keyring is specified then it will be created if it
1331 * doesn't yet exist. The old setting will be returned if successful.
1333 long keyctl_set_reqkey_keyring(int reqkey_defl)
1336 int ret, old_setting;
1338 old_setting = current_cred_xxx(jit_keyring);
1340 if (reqkey_defl == KEY_REQKEY_DEFL_NO_CHANGE)
1343 new = prepare_creds();
1347 switch (reqkey_defl) {
1348 case KEY_REQKEY_DEFL_THREAD_KEYRING:
1349 ret = install_thread_keyring_to_cred(new);
1354 case KEY_REQKEY_DEFL_PROCESS_KEYRING:
1355 ret = install_process_keyring_to_cred(new);
1360 case KEY_REQKEY_DEFL_DEFAULT:
1361 case KEY_REQKEY_DEFL_SESSION_KEYRING:
1362 case KEY_REQKEY_DEFL_USER_KEYRING:
1363 case KEY_REQKEY_DEFL_USER_SESSION_KEYRING:
1364 case KEY_REQKEY_DEFL_REQUESTOR_KEYRING:
1367 case KEY_REQKEY_DEFL_NO_CHANGE:
1368 case KEY_REQKEY_DEFL_GROUP_KEYRING:
1375 new->jit_keyring = reqkey_defl;
1384 * Set or clear the timeout on a key.
1386 * Either the key must grant the caller Setattr permission or else the caller
1387 * must hold an instantiation authorisation token for the key.
1389 * The timeout is either 0 to clear the timeout, or a number of seconds from
1390 * the current time. The key and any links to the key will be automatically
1391 * garbage collected after the timeout expires.
1393 * Keys with KEY_FLAG_KEEP set should not be timed out.
1395 * If successful, 0 is returned.
1397 long keyctl_set_timeout(key_serial_t id, unsigned timeout)
1399 struct key *key, *instkey;
1403 key_ref = lookup_user_key(id, KEY_LOOKUP_CREATE | KEY_LOOKUP_PARTIAL,
1405 if (IS_ERR(key_ref)) {
1406 /* setting the timeout on a key under construction is permitted
1407 * if we have the authorisation token handy */
1408 if (PTR_ERR(key_ref) == -EACCES) {
1409 instkey = key_get_instantiation_authkey(id);
1410 if (!IS_ERR(instkey)) {
1412 key_ref = lookup_user_key(id,
1415 if (!IS_ERR(key_ref))
1420 ret = PTR_ERR(key_ref);
1425 key = key_ref_to_ptr(key_ref);
1427 if (test_bit(KEY_FLAG_KEEP, &key->flags))
1430 key_set_timeout(key, timeout);
1438 * Assume (or clear) the authority to instantiate the specified key.
1440 * This sets the authoritative token currently in force for key instantiation.
1441 * This must be done for a key to be instantiated. It has the effect of making
1442 * available all the keys from the caller of the request_key() that created a
1443 * key to request_key() calls made by the caller of this function.
1445 * The caller must have the instantiation key in their process keyrings with a
1446 * Search permission grant available to the caller.
1448 * If the ID given is 0, then the setting will be cleared and 0 returned.
1450 * If the ID given has a matching an authorisation key, then that key will be
1451 * set and its ID will be returned. The authorisation key can be read to get
1452 * the callout information passed to request_key().
1454 long keyctl_assume_authority(key_serial_t id)
1456 struct key *authkey;
1459 /* special key IDs aren't permitted */
1464 /* we divest ourselves of authority if given an ID of 0 */
1466 ret = keyctl_change_reqkey_auth(NULL);
1470 /* attempt to assume the authority temporarily granted to us whilst we
1471 * instantiate the specified key
1472 * - the authorisation key must be in the current task's keyrings
1475 authkey = key_get_instantiation_authkey(id);
1476 if (IS_ERR(authkey)) {
1477 ret = PTR_ERR(authkey);
1481 ret = keyctl_change_reqkey_auth(authkey);
1483 ret = authkey->serial;
1490 * Get a key's the LSM security label.
1492 * The key must grant the caller View permission for this to work.
1494 * If there's a buffer, then up to buflen bytes of data will be placed into it.
1496 * If successful, the amount of information available will be returned,
1497 * irrespective of how much was copied (including the terminal NUL).
1499 long keyctl_get_security(key_serial_t keyid,
1500 char __user *buffer,
1503 struct key *key, *instkey;
1508 key_ref = lookup_user_key(keyid, KEY_LOOKUP_PARTIAL, KEY_NEED_VIEW);
1509 if (IS_ERR(key_ref)) {
1510 if (PTR_ERR(key_ref) != -EACCES)
1511 return PTR_ERR(key_ref);
1513 /* viewing a key under construction is also permitted if we
1514 * have the authorisation token handy */
1515 instkey = key_get_instantiation_authkey(keyid);
1516 if (IS_ERR(instkey))
1517 return PTR_ERR(instkey);
1520 key_ref = lookup_user_key(keyid, KEY_LOOKUP_PARTIAL, 0);
1521 if (IS_ERR(key_ref))
1522 return PTR_ERR(key_ref);
1525 key = key_ref_to_ptr(key_ref);
1526 ret = security_key_getsecurity(key, &context);
1528 /* if no information was returned, give userspace an empty
1531 if (buffer && buflen > 0 &&
1532 copy_to_user(buffer, "", 1) != 0)
1534 } else if (ret > 0) {
1535 /* return as much data as there's room for */
1536 if (buffer && buflen > 0) {
1540 if (copy_to_user(buffer, context, buflen) != 0)
1547 key_ref_put(key_ref);
1552 * Attempt to install the calling process's session keyring on the process's
1555 * The keyring must exist and must grant the caller LINK permission, and the
1556 * parent process must be single-threaded and must have the same effective
1557 * ownership as this process and mustn't be SUID/SGID.
1559 * The keyring will be emplaced on the parent when it next resumes userspace.
1561 * If successful, 0 will be returned.
1563 long keyctl_session_to_parent(void)
1565 struct task_struct *me, *parent;
1566 const struct cred *mycred, *pcred;
1567 struct callback_head *newwork, *oldwork;
1568 key_ref_t keyring_r;
1572 keyring_r = lookup_user_key(KEY_SPEC_SESSION_KEYRING, 0, KEY_NEED_LINK);
1573 if (IS_ERR(keyring_r))
1574 return PTR_ERR(keyring_r);
1578 /* our parent is going to need a new cred struct, a new tgcred struct
1579 * and new security data, so we allocate them here to prevent ENOMEM in
1581 cred = cred_alloc_blank();
1584 newwork = &cred->rcu;
1586 cred->session_keyring = key_ref_to_ptr(keyring_r);
1588 init_task_work(newwork, key_change_session_keyring);
1592 write_lock_irq(&tasklist_lock);
1596 parent = me->real_parent;
1598 /* the parent mustn't be init and mustn't be a kernel thread */
1599 if (parent->pid <= 1 || !parent->mm)
1602 /* the parent must be single threaded */
1603 if (!thread_group_empty(parent))
1606 /* the parent and the child must have different session keyrings or
1607 * there's no point */
1608 mycred = current_cred();
1609 pcred = __task_cred(parent);
1610 if (mycred == pcred ||
1611 mycred->session_keyring == pcred->session_keyring) {
1616 /* the parent must have the same effective ownership and mustn't be
1618 if (!uid_eq(pcred->uid, mycred->euid) ||
1619 !uid_eq(pcred->euid, mycred->euid) ||
1620 !uid_eq(pcred->suid, mycred->euid) ||
1621 !gid_eq(pcred->gid, mycred->egid) ||
1622 !gid_eq(pcred->egid, mycred->egid) ||
1623 !gid_eq(pcred->sgid, mycred->egid))
1626 /* the keyrings must have the same UID */
1627 if ((pcred->session_keyring &&
1628 !uid_eq(pcred->session_keyring->uid, mycred->euid)) ||
1629 !uid_eq(mycred->session_keyring->uid, mycred->euid))
1632 /* cancel an already pending keyring replacement */
1633 oldwork = task_work_cancel(parent, key_change_session_keyring);
1635 /* the replacement session keyring is applied just prior to userspace
1637 ret = task_work_add(parent, newwork, true);
1641 write_unlock_irq(&tasklist_lock);
1644 put_cred(container_of(oldwork, struct cred, rcu));
1650 key_ref_put(keyring_r);
1655 * Apply a restriction to a given keyring.
1657 * The caller must have Setattr permission to change keyring restrictions.
1659 * The requested type name may be a NULL pointer to reject all attempts
1660 * to link to the keyring. In this case, _restriction must also be NULL.
1661 * Otherwise, both _type and _restriction must be non-NULL.
1663 * Returns 0 if successful.
1665 long keyctl_restrict_keyring(key_serial_t id, const char __user *_type,
1666 const char __user *_restriction)
1670 char *restriction = NULL;
1673 key_ref = lookup_user_key(id, 0, KEY_NEED_SETATTR);
1674 if (IS_ERR(key_ref))
1675 return PTR_ERR(key_ref);
1682 ret = key_get_type_from_user(type, _type, sizeof(type));
1686 restriction = strndup_user(_restriction, PAGE_SIZE);
1687 if (IS_ERR(restriction)) {
1688 ret = PTR_ERR(restriction);
1696 ret = keyring_restrict(key_ref, _type ? type : NULL, restriction);
1699 key_ref_put(key_ref);
1704 * The key control system call
1706 SYSCALL_DEFINE5(keyctl, int, option, unsigned long, arg2, unsigned long, arg3,
1707 unsigned long, arg4, unsigned long, arg5)
1710 case KEYCTL_GET_KEYRING_ID:
1711 return keyctl_get_keyring_ID((key_serial_t) arg2,
1714 case KEYCTL_JOIN_SESSION_KEYRING:
1715 return keyctl_join_session_keyring((const char __user *) arg2);
1718 return keyctl_update_key((key_serial_t) arg2,
1719 (const void __user *) arg3,
1723 return keyctl_revoke_key((key_serial_t) arg2);
1725 case KEYCTL_DESCRIBE:
1726 return keyctl_describe_key((key_serial_t) arg2,
1727 (char __user *) arg3,
1731 return keyctl_keyring_clear((key_serial_t) arg2);
1734 return keyctl_keyring_link((key_serial_t) arg2,
1735 (key_serial_t) arg3);
1738 return keyctl_keyring_unlink((key_serial_t) arg2,
1739 (key_serial_t) arg3);
1742 return keyctl_keyring_search((key_serial_t) arg2,
1743 (const char __user *) arg3,
1744 (const char __user *) arg4,
1745 (key_serial_t) arg5);
1748 return keyctl_read_key((key_serial_t) arg2,
1749 (char __user *) arg3,
1753 return keyctl_chown_key((key_serial_t) arg2,
1757 case KEYCTL_SETPERM:
1758 return keyctl_setperm_key((key_serial_t) arg2,
1761 case KEYCTL_INSTANTIATE:
1762 return keyctl_instantiate_key((key_serial_t) arg2,
1763 (const void __user *) arg3,
1765 (key_serial_t) arg5);
1768 return keyctl_negate_key((key_serial_t) arg2,
1770 (key_serial_t) arg4);
1772 case KEYCTL_SET_REQKEY_KEYRING:
1773 return keyctl_set_reqkey_keyring(arg2);
1775 case KEYCTL_SET_TIMEOUT:
1776 return keyctl_set_timeout((key_serial_t) arg2,
1779 case KEYCTL_ASSUME_AUTHORITY:
1780 return keyctl_assume_authority((key_serial_t) arg2);
1782 case KEYCTL_GET_SECURITY:
1783 return keyctl_get_security((key_serial_t) arg2,
1784 (char __user *) arg3,
1787 case KEYCTL_SESSION_TO_PARENT:
1788 return keyctl_session_to_parent();
1791 return keyctl_reject_key((key_serial_t) arg2,
1794 (key_serial_t) arg5);
1796 case KEYCTL_INSTANTIATE_IOV:
1797 return keyctl_instantiate_key_iov(
1798 (key_serial_t) arg2,
1799 (const struct iovec __user *) arg3,
1801 (key_serial_t) arg5);
1803 case KEYCTL_INVALIDATE:
1804 return keyctl_invalidate_key((key_serial_t) arg2);
1806 case KEYCTL_GET_PERSISTENT:
1807 return keyctl_get_persistent((uid_t)arg2, (key_serial_t)arg3);
1809 case KEYCTL_DH_COMPUTE:
1810 return keyctl_dh_compute((struct keyctl_dh_params __user *) arg2,
1811 (char __user *) arg3, (size_t) arg4,
1812 (struct keyctl_kdf_params __user *) arg5);
1814 case KEYCTL_RESTRICT_KEYRING:
1815 return keyctl_restrict_keyring((key_serial_t) arg2,
1816 (const char __user *) arg3,
1817 (const char __user *) arg4);