include/keys/user-type.h

   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,
  49                       char __user *buffer, size_t buflen);
  50
  51 static inline const struct user_key_payload *user_key_payload_rcu(const struct key *key)
  52 {
  53         return (struct user_key_payload *)dereference_key_rcu(key);
  54 }
  55
  56 static inline struct user_key_payload *user_key_payload_locked(const struct key *key)
  57 {
  58         return (struct user_key_payload *)dereference_key_locked((struct key *)key);
  59 }
  60
  61 #endif /* CONFIG_KEYS */
  62
  63 #endif /* _KEYS_USER_TYPE_H */