include/keys/user-type.h

   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[0] __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,
  45                       char __user *buffer, size_t buflen);
  46
  47 static inline const struct user_key_payload *user_key_payload_rcu(const struct key *key)
  48 {
  49         return (struct user_key_payload *)dereference_key_rcu(key);
  50 }
  51
  52 static inline struct user_key_payload *user_key_payload_locked(const struct key *key)
  53 {
  54         return (struct user_key_payload *)dereference_key_locked((struct key *)key);
  55 }
  56
  57 #endif /* CONFIG_KEYS */
  58
  59 #endif /* _KEYS_USER_TYPE_H */