1 /* SPDX-License-Identifier: GPL-2.0-or-later */
2 /* user-type.h: User-defined key type
3  *
4  * Copyright (C) 2005 Red Hat, Inc. All Rights Reserved.
5  * Written by David Howells (dhowells@redhat.com)
6  */
7 
8 #ifndef _KEYS_USER_TYPE_H
9 #define _KEYS_USER_TYPE_H
10 
11 #include <linux/key.h>
12 #include <linux/rcupdate.h>
13 
14 #ifdef CONFIG_KEYS
15 
16 /*****************************************************************************/
17 /*
18  * the payload for a key of type "user" or "logon"
19  * - once filled in and attached to a key:
20  *   - the payload struct is invariant may not be changed, only replaced
21  *   - the payload must be read with RCU procedures or with the key semaphore
22  *     held
23  *   - the payload may only be replaced with the key semaphore write-locked
24  * - the key's data length is the size of the actual data, not including the
25  *   payload wrapper
26  */
27 struct user_key_payload {
28 	struct rcu_head	rcu;		/* RCU destructor */
29 	unsigned short	datalen;	/* length of this data */
30 	char		data[] __aligned(__alignof__(u64)); /* actual data */
31 };
32 
33 extern struct key_type key_type_user;
34 extern struct key_type key_type_logon;
35 
36 struct key_preparsed_payload;
37 
38 extern int user_preparse(struct key_preparsed_payload *prep);
39 extern void user_free_preparse(struct key_preparsed_payload *prep);
40 extern int user_update(struct key *key, struct key_preparsed_payload *prep);
41 extern void user_revoke(struct key *key);
42 extern void user_destroy(struct key *key);
43 extern void user_describe(const struct key *user, struct seq_file *m);
44 extern long user_read(const struct key *key, char *buffer, size_t buflen);
45 
user_key_payload_rcu(const struct key * key)46 static inline const struct user_key_payload *user_key_payload_rcu(const struct key *key)
47 {
48 	return (struct user_key_payload *)dereference_key_rcu(key);
49 }
50 
user_key_payload_locked(const struct key * key)51 static inline struct user_key_payload *user_key_payload_locked(const struct key *key)
52 {
53 	return (struct user_key_payload *)dereference_key_locked((struct key *)key);
54 }
55 
56 #endif /* CONFIG_KEYS */
57 
58 #endif /* _KEYS_USER_TYPE_H */
59