1 /* keyctl.c: userspace keyctl operations
3 * Copyright (C) 2004-5 Red Hat, Inc. All Rights Reserved.
4 * Written by David Howells (dhowells@redhat.com)
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public License
8 * as published by the Free Software Foundation; either version
9 * 2 of the License, or (at your option) any later version.
12 #include <linux/module.h>
13 #include <linux/init.h>
14 #include <linux/sched.h>
15 #include <linux/slab.h>
16 #include <linux/syscalls.h>
17 #include <linux/keyctl.h>
19 #include <linux/capability.h>
20 #include <linux/string.h>
21 #include <linux/err.h>
22 #include <linux/vmalloc.h>
23 #include <linux/security.h>
24 #include <asm/uaccess.h>
27 static int key_get_type_from_user(char *type,
28 const char __user *_type,
33 ret = strncpy_from_user(type, _type, len);
38 if (ret == 0 || ret >= len)
49 /*****************************************************************************/
51 * extract the description of a new key from userspace and either add it as a
52 * new key to the specified keyring or update a matching key in that keyring
53 * - the keyring must be writable
54 * - returns the new key's serial number
55 * - implements add_key()
57 SYSCALL_DEFINE5(add_key, const char __user *, _type,
58 const char __user *, _description,
59 const void __user *, _payload,
63 key_ref_t keyring_ref, key_ref;
64 char type[32], *description;
70 if (plen > 1024 * 1024 - 1)
73 /* draw all the data into kernel space */
74 ret = key_get_type_from_user(type, _type, sizeof(type));
78 description = strndup_user(_description, PAGE_SIZE);
79 if (IS_ERR(description)) {
80 ret = PTR_ERR(description);
84 /* pull the payload in if one was supplied */
90 payload = kmalloc(plen, GFP_KERNEL);
92 if (plen <= PAGE_SIZE)
95 payload = vmalloc(plen);
101 if (copy_from_user(payload, _payload, plen) != 0)
105 /* find the target keyring (which must be writable) */
106 keyring_ref = lookup_user_key(ringid, KEY_LOOKUP_CREATE, KEY_WRITE);
107 if (IS_ERR(keyring_ref)) {
108 ret = PTR_ERR(keyring_ref);
112 /* create or update the requested key and add it to the target
114 key_ref = key_create_or_update(keyring_ref, type, description,
115 payload, plen, KEY_PERM_UNDEF,
117 if (!IS_ERR(key_ref)) {
118 ret = key_ref_to_ptr(key_ref)->serial;
119 key_ref_put(key_ref);
122 ret = PTR_ERR(key_ref);
125 key_ref_put(keyring_ref);
136 } /* end sys_add_key() */
138 /*****************************************************************************/
140 * search the process keyrings for a matching key
141 * - nested keyrings may also be searched if they have Search permission
142 * - if a key is found, it will be attached to the destination keyring if
143 * there's one specified
144 * - /sbin/request-key will be invoked if _callout_info is non-NULL
145 * - the _callout_info string will be passed to /sbin/request-key
146 * - if the _callout_info string is empty, it will be rendered as "-"
147 * - implements request_key()
149 SYSCALL_DEFINE4(request_key, const char __user *, _type,
150 const char __user *, _description,
151 const char __user *, _callout_info,
152 key_serial_t, destringid)
154 struct key_type *ktype;
158 char type[32], *description, *callout_info;
161 /* pull the type into kernel space */
162 ret = key_get_type_from_user(type, _type, sizeof(type));
166 /* pull the description into kernel space */
167 description = strndup_user(_description, PAGE_SIZE);
168 if (IS_ERR(description)) {
169 ret = PTR_ERR(description);
173 /* pull the callout info into kernel space */
177 callout_info = strndup_user(_callout_info, PAGE_SIZE);
178 if (IS_ERR(callout_info)) {
179 ret = PTR_ERR(callout_info);
182 callout_len = strlen(callout_info);
185 /* get the destination keyring if specified */
188 dest_ref = lookup_user_key(destringid, KEY_LOOKUP_CREATE,
190 if (IS_ERR(dest_ref)) {
191 ret = PTR_ERR(dest_ref);
196 /* find the key type */
197 ktype = key_type_lookup(type);
199 ret = PTR_ERR(ktype);
204 key = request_key_and_link(ktype, description, callout_info,
205 callout_len, NULL, key_ref_to_ptr(dest_ref),
218 key_ref_put(dest_ref);
226 } /* end sys_request_key() */
228 /*****************************************************************************/
230 * get the ID of the specified process keyring
231 * - the keyring must have search permission to be found
232 * - implements keyctl(KEYCTL_GET_KEYRING_ID)
234 long keyctl_get_keyring_ID(key_serial_t id, int create)
237 unsigned long lflags;
240 lflags = create ? KEY_LOOKUP_CREATE : 0;
241 key_ref = lookup_user_key(id, lflags, KEY_SEARCH);
242 if (IS_ERR(key_ref)) {
243 ret = PTR_ERR(key_ref);
247 ret = key_ref_to_ptr(key_ref)->serial;
248 key_ref_put(key_ref);
252 } /* end keyctl_get_keyring_ID() */
254 /*****************************************************************************/
256 * join the session keyring
257 * - implements keyctl(KEYCTL_JOIN_SESSION_KEYRING)
259 long keyctl_join_session_keyring(const char __user *_name)
264 /* fetch the name from userspace */
267 name = strndup_user(_name, PAGE_SIZE);
274 /* join the session */
275 ret = join_session_keyring(name);
281 } /* end keyctl_join_session_keyring() */
283 /*****************************************************************************/
285 * update a key's data payload
286 * - the key must be writable
287 * - implements keyctl(KEYCTL_UPDATE)
289 long keyctl_update_key(key_serial_t id,
290 const void __user *_payload,
298 if (plen > PAGE_SIZE)
301 /* pull the payload in if one was supplied */
305 payload = kmalloc(plen, GFP_KERNEL);
310 if (copy_from_user(payload, _payload, plen) != 0)
314 /* find the target key (which must be writable) */
315 key_ref = lookup_user_key(id, 0, KEY_WRITE);
316 if (IS_ERR(key_ref)) {
317 ret = PTR_ERR(key_ref);
322 ret = key_update(key_ref, payload, plen);
324 key_ref_put(key_ref);
330 } /* end keyctl_update_key() */
332 /*****************************************************************************/
335 * - the key must be writable
336 * - implements keyctl(KEYCTL_REVOKE)
338 long keyctl_revoke_key(key_serial_t id)
343 key_ref = lookup_user_key(id, 0, KEY_WRITE);
344 if (IS_ERR(key_ref)) {
345 ret = PTR_ERR(key_ref);
348 key_ref = lookup_user_key(id, 0, KEY_SETATTR);
349 if (IS_ERR(key_ref)) {
350 ret = PTR_ERR(key_ref);
355 key_revoke(key_ref_to_ptr(key_ref));
358 key_ref_put(key_ref);
362 } /* end keyctl_revoke_key() */
364 /*****************************************************************************/
366 * clear the specified process keyring
367 * - the keyring must be writable
368 * - implements keyctl(KEYCTL_CLEAR)
370 long keyctl_keyring_clear(key_serial_t ringid)
372 key_ref_t keyring_ref;
375 keyring_ref = lookup_user_key(ringid, KEY_LOOKUP_CREATE, KEY_WRITE);
376 if (IS_ERR(keyring_ref)) {
377 ret = PTR_ERR(keyring_ref);
381 ret = keyring_clear(key_ref_to_ptr(keyring_ref));
383 key_ref_put(keyring_ref);
387 } /* end keyctl_keyring_clear() */
389 /*****************************************************************************/
391 * link a key into a keyring
392 * - the keyring must be writable
393 * - the key must be linkable
394 * - implements keyctl(KEYCTL_LINK)
396 long keyctl_keyring_link(key_serial_t id, key_serial_t ringid)
398 key_ref_t keyring_ref, key_ref;
401 keyring_ref = lookup_user_key(ringid, KEY_LOOKUP_CREATE, KEY_WRITE);
402 if (IS_ERR(keyring_ref)) {
403 ret = PTR_ERR(keyring_ref);
407 key_ref = lookup_user_key(id, KEY_LOOKUP_CREATE, KEY_LINK);
408 if (IS_ERR(key_ref)) {
409 ret = PTR_ERR(key_ref);
413 ret = key_link(key_ref_to_ptr(keyring_ref), key_ref_to_ptr(key_ref));
415 key_ref_put(key_ref);
417 key_ref_put(keyring_ref);
421 } /* end keyctl_keyring_link() */
423 /*****************************************************************************/
425 * unlink the first attachment of a key from a keyring
426 * - the keyring must be writable
427 * - we don't need any permissions on the key
428 * - implements keyctl(KEYCTL_UNLINK)
430 long keyctl_keyring_unlink(key_serial_t id, key_serial_t ringid)
432 key_ref_t keyring_ref, key_ref;
435 keyring_ref = lookup_user_key(ringid, 0, KEY_WRITE);
436 if (IS_ERR(keyring_ref)) {
437 ret = PTR_ERR(keyring_ref);
441 key_ref = lookup_user_key(id, KEY_LOOKUP_FOR_UNLINK, 0);
442 if (IS_ERR(key_ref)) {
443 ret = PTR_ERR(key_ref);
447 ret = key_unlink(key_ref_to_ptr(keyring_ref), key_ref_to_ptr(key_ref));
449 key_ref_put(key_ref);
451 key_ref_put(keyring_ref);
455 } /* end keyctl_keyring_unlink() */
457 /*****************************************************************************/
459 * describe a user key
460 * - the key must have view permission
461 * - if there's a buffer, we place up to buflen bytes of data into it
462 * - unless there's an error, we return the amount of description available,
463 * irrespective of how much we may have copied
464 * - the description is formatted thus:
465 * type;uid;gid;perm;description<NUL>
466 * - implements keyctl(KEYCTL_DESCRIBE)
468 long keyctl_describe_key(key_serial_t keyid,
472 struct key *key, *instkey;
477 key_ref = lookup_user_key(keyid, KEY_LOOKUP_PARTIAL, KEY_VIEW);
478 if (IS_ERR(key_ref)) {
479 /* viewing a key under construction is permitted if we have the
480 * authorisation token handy */
481 if (PTR_ERR(key_ref) == -EACCES) {
482 instkey = key_get_instantiation_authkey(keyid);
483 if (!IS_ERR(instkey)) {
485 key_ref = lookup_user_key(keyid,
488 if (!IS_ERR(key_ref))
493 ret = PTR_ERR(key_ref);
498 /* calculate how much description we're going to return */
500 tmpbuf = kmalloc(PAGE_SIZE, GFP_KERNEL);
504 key = key_ref_to_ptr(key_ref);
506 ret = snprintf(tmpbuf, PAGE_SIZE - 1,
512 key->description ?: "");
514 /* include a NUL char at the end of the data */
515 if (ret > PAGE_SIZE - 1)
520 /* consider returning the data */
521 if (buffer && buflen > 0) {
525 if (copy_to_user(buffer, tmpbuf, buflen) != 0)
531 key_ref_put(key_ref);
535 } /* end keyctl_describe_key() */
537 /*****************************************************************************/
539 * search the specified keyring for a matching key
540 * - the start keyring must be searchable
541 * - nested keyrings may also be searched if they are searchable
542 * - only keys with search permission may be found
543 * - if a key is found, it will be attached to the destination keyring if
544 * there's one specified
545 * - implements keyctl(KEYCTL_SEARCH)
547 long keyctl_keyring_search(key_serial_t ringid,
548 const char __user *_type,
549 const char __user *_description,
550 key_serial_t destringid)
552 struct key_type *ktype;
553 key_ref_t keyring_ref, key_ref, dest_ref;
554 char type[32], *description;
557 /* pull the type and description into kernel space */
558 ret = key_get_type_from_user(type, _type, sizeof(type));
562 description = strndup_user(_description, PAGE_SIZE);
563 if (IS_ERR(description)) {
564 ret = PTR_ERR(description);
568 /* get the keyring at which to begin the search */
569 keyring_ref = lookup_user_key(ringid, 0, KEY_SEARCH);
570 if (IS_ERR(keyring_ref)) {
571 ret = PTR_ERR(keyring_ref);
575 /* get the destination keyring if specified */
578 dest_ref = lookup_user_key(destringid, KEY_LOOKUP_CREATE,
580 if (IS_ERR(dest_ref)) {
581 ret = PTR_ERR(dest_ref);
586 /* find the key type */
587 ktype = key_type_lookup(type);
589 ret = PTR_ERR(ktype);
594 key_ref = keyring_search(keyring_ref, ktype, description);
595 if (IS_ERR(key_ref)) {
596 ret = PTR_ERR(key_ref);
598 /* treat lack or presence of a negative key the same */
604 /* link the resulting key to the destination keyring if we can */
606 ret = key_permission(key_ref, KEY_LINK);
610 ret = key_link(key_ref_to_ptr(dest_ref), key_ref_to_ptr(key_ref));
615 ret = key_ref_to_ptr(key_ref)->serial;
618 key_ref_put(key_ref);
622 key_ref_put(dest_ref);
624 key_ref_put(keyring_ref);
630 } /* end keyctl_keyring_search() */
632 /*****************************************************************************/
634 * read a user key's payload
635 * - the keyring must be readable or the key must be searchable from the
637 * - if there's a buffer, we place up to buflen bytes of data into it
638 * - unless there's an error, we return the amount of data in the key,
639 * irrespective of how much we may have copied
640 * - implements keyctl(KEYCTL_READ)
642 long keyctl_read_key(key_serial_t keyid, char __user *buffer, size_t buflen)
648 /* find the key first */
649 key_ref = lookup_user_key(keyid, 0, 0);
650 if (IS_ERR(key_ref)) {
655 key = key_ref_to_ptr(key_ref);
657 /* see if we can read it directly */
658 ret = key_permission(key_ref, KEY_READ);
664 /* we can't; see if it's searchable from this process's keyrings
665 * - we automatically take account of the fact that it may be
666 * dangling off an instantiation key
668 if (!is_key_possessed(key_ref)) {
673 /* the key is probably readable - now try to read it */
675 ret = key_validate(key);
678 if (key->type->read) {
679 /* read the data with the semaphore held (since we
681 down_read(&key->sem);
682 ret = key->type->read(key, buffer, buflen);
692 } /* end keyctl_read_key() */
694 /*****************************************************************************/
696 * change the ownership of a key
697 * - the keyring owned by the changer
698 * - if the uid or gid is -1, then that parameter is not changed
699 * - implements keyctl(KEYCTL_CHOWN)
701 long keyctl_chown_key(key_serial_t id, uid_t uid, gid_t gid)
703 struct key_user *newowner, *zapowner = NULL;
709 if (uid == (uid_t) -1 && gid == (gid_t) -1)
712 key_ref = lookup_user_key(id, KEY_LOOKUP_CREATE | KEY_LOOKUP_PARTIAL,
714 if (IS_ERR(key_ref)) {
715 ret = PTR_ERR(key_ref);
719 key = key_ref_to_ptr(key_ref);
721 /* make the changes with the locks held to prevent chown/chown races */
723 down_write(&key->sem);
725 if (!capable(CAP_SYS_ADMIN)) {
726 /* only the sysadmin can chown a key to some other UID */
727 if (uid != (uid_t) -1 && key->uid != uid)
730 /* only the sysadmin can set the key's GID to a group other
731 * than one of those that the current process subscribes to */
732 if (gid != (gid_t) -1 && gid != key->gid && !in_group_p(gid))
737 if (uid != (uid_t) -1 && uid != key->uid) {
739 newowner = key_user_lookup(uid, current_user_ns());
743 /* transfer the quota burden to the new user */
744 if (test_bit(KEY_FLAG_IN_QUOTA, &key->flags)) {
745 unsigned maxkeys = (uid == 0) ?
746 key_quota_root_maxkeys : key_quota_maxkeys;
747 unsigned maxbytes = (uid == 0) ?
748 key_quota_root_maxbytes : key_quota_maxbytes;
750 spin_lock(&newowner->lock);
751 if (newowner->qnkeys + 1 >= maxkeys ||
752 newowner->qnbytes + key->quotalen >= maxbytes ||
753 newowner->qnbytes + key->quotalen <
758 newowner->qnbytes += key->quotalen;
759 spin_unlock(&newowner->lock);
761 spin_lock(&key->user->lock);
763 key->user->qnbytes -= key->quotalen;
764 spin_unlock(&key->user->lock);
767 atomic_dec(&key->user->nkeys);
768 atomic_inc(&newowner->nkeys);
770 if (test_bit(KEY_FLAG_INSTANTIATED, &key->flags)) {
771 atomic_dec(&key->user->nikeys);
772 atomic_inc(&newowner->nikeys);
775 zapowner = key->user;
776 key->user = newowner;
781 if (gid != (gid_t) -1)
790 key_user_put(zapowner);
795 spin_unlock(&newowner->lock);
800 } /* end keyctl_chown_key() */
802 /*****************************************************************************/
804 * change the permission mask on a key
805 * - the keyring owned by the changer
806 * - implements keyctl(KEYCTL_SETPERM)
808 long keyctl_setperm_key(key_serial_t id, key_perm_t perm)
815 if (perm & ~(KEY_POS_ALL | KEY_USR_ALL | KEY_GRP_ALL | KEY_OTH_ALL))
818 key_ref = lookup_user_key(id, KEY_LOOKUP_CREATE | KEY_LOOKUP_PARTIAL,
820 if (IS_ERR(key_ref)) {
821 ret = PTR_ERR(key_ref);
825 key = key_ref_to_ptr(key_ref);
827 /* make the changes with the locks held to prevent chown/chmod races */
829 down_write(&key->sem);
831 /* if we're not the sysadmin, we can only change a key that we own */
832 if (capable(CAP_SYS_ADMIN) || key->uid == current_fsuid()) {
842 } /* end keyctl_setperm_key() */
845 * get the destination keyring for instantiation
847 static long get_instantiation_keyring(key_serial_t ringid,
848 struct request_key_auth *rka,
849 struct key **_dest_keyring)
853 *_dest_keyring = NULL;
855 /* just return a NULL pointer if we weren't asked to make a link */
859 /* if a specific keyring is nominated by ID, then use that */
861 dkref = lookup_user_key(ringid, KEY_LOOKUP_CREATE, KEY_WRITE);
863 return PTR_ERR(dkref);
864 *_dest_keyring = key_ref_to_ptr(dkref);
868 if (ringid == KEY_SPEC_REQKEY_AUTH_KEY)
871 /* otherwise specify the destination keyring recorded in the
872 * authorisation key (any KEY_SPEC_*_KEYRING) */
873 if (ringid >= KEY_SPEC_REQUESTOR_KEYRING) {
874 *_dest_keyring = key_get(rka->dest_keyring);
882 * change the request_key authorisation key on the current process
884 static int keyctl_change_reqkey_auth(struct key *key)
888 new = prepare_creds();
892 key_put(new->request_key_auth);
893 new->request_key_auth = key_get(key);
895 return commit_creds(new);
898 /*****************************************************************************/
900 * instantiate the key with the specified payload, and, if one is given, link
901 * the key into the keyring
903 long keyctl_instantiate_key(key_serial_t id,
904 const void __user *_payload,
908 const struct cred *cred = current_cred();
909 struct request_key_auth *rka;
910 struct key *instkey, *dest_keyring;
915 kenter("%d,,%zu,%d", id, plen, ringid);
918 if (plen > 1024 * 1024 - 1)
921 /* the appropriate instantiation authorisation key must have been
922 * assumed before calling this */
924 instkey = cred->request_key_auth;
928 rka = instkey->payload.data;
929 if (rka->target_key->serial != id)
932 /* pull the payload in if one was supplied */
937 payload = kmalloc(plen, GFP_KERNEL);
939 if (plen <= PAGE_SIZE)
942 payload = vmalloc(plen);
948 if (copy_from_user(payload, _payload, plen) != 0)
952 /* find the destination keyring amongst those belonging to the
954 ret = get_instantiation_keyring(ringid, rka, &dest_keyring);
958 /* instantiate the key and link it into a keyring */
959 ret = key_instantiate_and_link(rka->target_key, payload, plen,
960 dest_keyring, instkey);
962 key_put(dest_keyring);
964 /* discard the assumed authority if it's just been disabled by
965 * instantiation of the key */
967 keyctl_change_reqkey_auth(NULL);
977 } /* end keyctl_instantiate_key() */
979 /*****************************************************************************/
981 * negatively instantiate the key with the given timeout (in seconds), and, if
982 * one is given, link the key into the keyring
984 long keyctl_negate_key(key_serial_t id, unsigned timeout, key_serial_t ringid)
986 const struct cred *cred = current_cred();
987 struct request_key_auth *rka;
988 struct key *instkey, *dest_keyring;
991 kenter("%d,%u,%d", id, timeout, ringid);
993 /* the appropriate instantiation authorisation key must have been
994 * assumed before calling this */
996 instkey = cred->request_key_auth;
1000 rka = instkey->payload.data;
1001 if (rka->target_key->serial != id)
1004 /* find the destination keyring if present (which must also be
1006 ret = get_instantiation_keyring(ringid, rka, &dest_keyring);
1010 /* instantiate the key and link it into a keyring */
1011 ret = key_negate_and_link(rka->target_key, timeout,
1012 dest_keyring, instkey);
1014 key_put(dest_keyring);
1016 /* discard the assumed authority if it's just been disabled by
1017 * instantiation of the key */
1019 keyctl_change_reqkey_auth(NULL);
1024 } /* end keyctl_negate_key() */
1026 /*****************************************************************************/
1028 * set the default keyring in which request_key() will cache keys
1029 * - return the old setting
1031 long keyctl_set_reqkey_keyring(int reqkey_defl)
1034 int ret, old_setting;
1036 old_setting = current_cred_xxx(jit_keyring);
1038 if (reqkey_defl == KEY_REQKEY_DEFL_NO_CHANGE)
1041 new = prepare_creds();
1045 switch (reqkey_defl) {
1046 case KEY_REQKEY_DEFL_THREAD_KEYRING:
1047 ret = install_thread_keyring_to_cred(new);
1052 case KEY_REQKEY_DEFL_PROCESS_KEYRING:
1053 ret = install_process_keyring_to_cred(new);
1061 case KEY_REQKEY_DEFL_DEFAULT:
1062 case KEY_REQKEY_DEFL_SESSION_KEYRING:
1063 case KEY_REQKEY_DEFL_USER_KEYRING:
1064 case KEY_REQKEY_DEFL_USER_SESSION_KEYRING:
1065 case KEY_REQKEY_DEFL_REQUESTOR_KEYRING:
1068 case KEY_REQKEY_DEFL_NO_CHANGE:
1069 case KEY_REQKEY_DEFL_GROUP_KEYRING:
1076 new->jit_keyring = reqkey_defl;
1083 } /* end keyctl_set_reqkey_keyring() */
1085 /*****************************************************************************/
1087 * set or clear the timeout for a key
1089 long keyctl_set_timeout(key_serial_t id, unsigned timeout)
1091 struct timespec now;
1092 struct key *key, *instkey;
1097 key_ref = lookup_user_key(id, KEY_LOOKUP_CREATE | KEY_LOOKUP_PARTIAL,
1099 if (IS_ERR(key_ref)) {
1100 /* setting the timeout on a key under construction is permitted
1101 * if we have the authorisation token handy */
1102 if (PTR_ERR(key_ref) == -EACCES) {
1103 instkey = key_get_instantiation_authkey(id);
1104 if (!IS_ERR(instkey)) {
1106 key_ref = lookup_user_key(id,
1109 if (!IS_ERR(key_ref))
1114 ret = PTR_ERR(key_ref);
1119 key = key_ref_to_ptr(key_ref);
1121 /* make the changes with the locks held to prevent races */
1122 down_write(&key->sem);
1126 now = current_kernel_time();
1127 expiry = now.tv_sec + timeout;
1130 key->expiry = expiry;
1131 key_schedule_gc(key->expiry + key_gc_delay);
1133 up_write(&key->sem);
1140 } /* end keyctl_set_timeout() */
1142 /*****************************************************************************/
1144 * assume the authority to instantiate the specified key
1146 long keyctl_assume_authority(key_serial_t id)
1148 struct key *authkey;
1151 /* special key IDs aren't permitted */
1156 /* we divest ourselves of authority if given an ID of 0 */
1158 ret = keyctl_change_reqkey_auth(NULL);
1162 /* attempt to assume the authority temporarily granted to us whilst we
1163 * instantiate the specified key
1164 * - the authorisation key must be in the current task's keyrings
1167 authkey = key_get_instantiation_authkey(id);
1168 if (IS_ERR(authkey)) {
1169 ret = PTR_ERR(authkey);
1173 ret = keyctl_change_reqkey_auth(authkey);
1178 ret = authkey->serial;
1182 } /* end keyctl_assume_authority() */
1185 * get the security label of a key
1186 * - the key must grant us view permission
1187 * - if there's a buffer, we place up to buflen bytes of data into it
1188 * - unless there's an error, we return the amount of information available,
1189 * irrespective of how much we may have copied (including the terminal NUL)
1190 * - implements keyctl(KEYCTL_GET_SECURITY)
1192 long keyctl_get_security(key_serial_t keyid,
1193 char __user *buffer,
1196 struct key *key, *instkey;
1201 key_ref = lookup_user_key(keyid, KEY_LOOKUP_PARTIAL, KEY_VIEW);
1202 if (IS_ERR(key_ref)) {
1203 if (PTR_ERR(key_ref) != -EACCES)
1204 return PTR_ERR(key_ref);
1206 /* viewing a key under construction is also permitted if we
1207 * have the authorisation token handy */
1208 instkey = key_get_instantiation_authkey(keyid);
1209 if (IS_ERR(instkey))
1210 return PTR_ERR(instkey);
1213 key_ref = lookup_user_key(keyid, KEY_LOOKUP_PARTIAL, 0);
1214 if (IS_ERR(key_ref))
1215 return PTR_ERR(key_ref);
1218 key = key_ref_to_ptr(key_ref);
1219 ret = security_key_getsecurity(key, &context);
1221 /* if no information was returned, give userspace an empty
1224 if (buffer && buflen > 0 &&
1225 copy_to_user(buffer, "", 1) != 0)
1227 } else if (ret > 0) {
1228 /* return as much data as there's room for */
1229 if (buffer && buflen > 0) {
1233 if (copy_to_user(buffer, context, buflen) != 0)
1240 key_ref_put(key_ref);
1245 * attempt to install the calling process's session keyring on the process's
1247 * - the keyring must exist and must grant us LINK permission
1248 * - implements keyctl(KEYCTL_SESSION_TO_PARENT)
1250 long keyctl_session_to_parent(void)
1252 #ifdef TIF_NOTIFY_RESUME
1253 struct task_struct *me, *parent;
1254 const struct cred *mycred, *pcred;
1255 struct cred *cred, *oldcred;
1256 key_ref_t keyring_r;
1259 keyring_r = lookup_user_key(KEY_SPEC_SESSION_KEYRING, 0, KEY_LINK);
1260 if (IS_ERR(keyring_r))
1261 return PTR_ERR(keyring_r);
1263 /* our parent is going to need a new cred struct, a new tgcred struct
1264 * and new security data, so we allocate them here to prevent ENOMEM in
1267 cred = cred_alloc_blank();
1271 cred->tgcred->session_keyring = key_ref_to_ptr(keyring_r);
1275 write_lock_irq(&tasklist_lock);
1277 parent = me->real_parent;
1280 /* the parent mustn't be init and mustn't be a kernel thread */
1281 if (parent->pid <= 1 || !parent->mm)
1284 /* the parent must be single threaded */
1285 if (!thread_group_empty(parent))
1288 /* the parent and the child must have different session keyrings or
1289 * there's no point */
1290 mycred = current_cred();
1291 pcred = __task_cred(parent);
1292 if (mycred == pcred ||
1293 mycred->tgcred->session_keyring == pcred->tgcred->session_keyring)
1296 /* the parent must have the same effective ownership and mustn't be
1298 if (pcred->uid != mycred->euid ||
1299 pcred->euid != mycred->euid ||
1300 pcred->suid != mycred->euid ||
1301 pcred->gid != mycred->egid ||
1302 pcred->egid != mycred->egid ||
1303 pcred->sgid != mycred->egid)
1306 /* the keyrings must have the same UID */
1307 if (pcred->tgcred->session_keyring->uid != mycred->euid ||
1308 mycred->tgcred->session_keyring->uid != mycred->euid)
1311 /* if there's an already pending keyring replacement, then we replace
1313 oldcred = parent->replacement_session_keyring;
1315 /* the replacement session keyring is applied just prior to userspace
1317 parent->replacement_session_keyring = cred;
1319 set_ti_thread_flag(task_thread_info(parent), TIF_NOTIFY_RESUME);
1321 write_unlock_irq(&tasklist_lock);
1329 write_unlock_irq(&tasklist_lock);
1334 key_ref_put(keyring_r);
1337 #else /* !TIF_NOTIFY_RESUME */
1339 * To be removed when TIF_NOTIFY_RESUME has been implemented on
1342 #warning TIF_NOTIFY_RESUME not implemented
1344 #endif /* !TIF_NOTIFY_RESUME */
1347 /*****************************************************************************/
1349 * the key control system call
1351 SYSCALL_DEFINE5(keyctl, int, option, unsigned long, arg2, unsigned long, arg3,
1352 unsigned long, arg4, unsigned long, arg5)
1355 case KEYCTL_GET_KEYRING_ID:
1356 return keyctl_get_keyring_ID((key_serial_t) arg2,
1359 case KEYCTL_JOIN_SESSION_KEYRING:
1360 return keyctl_join_session_keyring((const char __user *) arg2);
1363 return keyctl_update_key((key_serial_t) arg2,
1364 (const void __user *) arg3,
1368 return keyctl_revoke_key((key_serial_t) arg2);
1370 case KEYCTL_DESCRIBE:
1371 return keyctl_describe_key((key_serial_t) arg2,
1372 (char __user *) arg3,
1376 return keyctl_keyring_clear((key_serial_t) arg2);
1379 return keyctl_keyring_link((key_serial_t) arg2,
1380 (key_serial_t) arg3);
1383 return keyctl_keyring_unlink((key_serial_t) arg2,
1384 (key_serial_t) arg3);
1387 return keyctl_keyring_search((key_serial_t) arg2,
1388 (const char __user *) arg3,
1389 (const char __user *) arg4,
1390 (key_serial_t) arg5);
1393 return keyctl_read_key((key_serial_t) arg2,
1394 (char __user *) arg3,
1398 return keyctl_chown_key((key_serial_t) arg2,
1402 case KEYCTL_SETPERM:
1403 return keyctl_setperm_key((key_serial_t) arg2,
1406 case KEYCTL_INSTANTIATE:
1407 return keyctl_instantiate_key((key_serial_t) arg2,
1408 (const void __user *) arg3,
1410 (key_serial_t) arg5);
1413 return keyctl_negate_key((key_serial_t) arg2,
1415 (key_serial_t) arg4);
1417 case KEYCTL_SET_REQKEY_KEYRING:
1418 return keyctl_set_reqkey_keyring(arg2);
1420 case KEYCTL_SET_TIMEOUT:
1421 return keyctl_set_timeout((key_serial_t) arg2,
1424 case KEYCTL_ASSUME_AUTHORITY:
1425 return keyctl_assume_authority((key_serial_t) arg2);
1427 case KEYCTL_GET_SECURITY:
1428 return keyctl_get_security((key_serial_t) arg2,
1429 (char __user *) arg3,
1432 case KEYCTL_SESSION_TO_PARENT:
1433 return keyctl_session_to_parent();
1439 } /* end sys_keyctl() */