1 /* user-type.h: User-defined key type
2  *
3  * Copyright (C) 2005 Red Hat, Inc. All Rights Reserved.
4  * Written by David Howells (dhowells@redhat.com)
5  *
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.
10  */
11 
12 #ifndef _KEYS_USER_TYPE_H
13 #define _KEYS_USER_TYPE_H
14 
15 #include <linux/key.h>
16 #include <linux/rcupdate.h>
17 
18 #ifdef CONFIG_KEYS
19 
20 /*****************************************************************************/
21 /*
22  * the payload for a key of type "user" or "logon"
23  * - once filled in and attached to a key:
24  *   - the payload struct is invariant may not be changed, only replaced
25  *   - the payload must be read with RCU procedures or with the key semaphore
26  *     held
27  *   - the payload may only be replaced with the key semaphore write-locked
28  * - the key's data length is the size of the actual data, not including the
29  *   payload wrapper
30  */
31 struct user_key_payload {
32 	struct rcu_head	rcu;		/* RCU destructor */
33 	unsigned short	datalen;	/* length of this data */
34 	char		data[0] __aligned(__alignof__(u64)); /* actual data */
35 };
36 
37 extern struct key_type key_type_user;
38 extern struct key_type key_type_logon;
39 
40 struct key_preparsed_payload;
41 
42 extern int user_preparse(struct key_preparsed_payload *prep);
43 extern void user_free_preparse(struct key_preparsed_payload *prep);
44 extern int user_update(struct key *key, struct key_preparsed_payload *prep);
45 extern void user_revoke(struct key *key);
46 extern void user_destroy(struct key *key);
47 extern void user_describe(const struct key *user, struct seq_file *m);
48 extern long user_read(const struct key *key, char *buffer, size_t buflen);
49 
user_key_payload_rcu(const struct key * key)50 static inline const struct user_key_payload *user_key_payload_rcu(const struct key *key)
51 {
52 	return (struct user_key_payload *)dereference_key_rcu(key);
53 }
54 
user_key_payload_locked(const struct key * key)55 static inline struct user_key_payload *user_key_payload_locked(const struct key *key)
56 {
57 	return (struct user_key_payload *)dereference_key_locked((struct key *)key);
58 }
59 
60 #endif /* CONFIG_KEYS */
61 
62 #endif /* _KEYS_USER_TYPE_H */
63