LXR linux/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 */
  27struct 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
  33extern struct key_type key_type_user;
  34extern struct key_type key_type_logon;
  35
  36struct key_preparsed_payload;
  37
  38extern int user_preparse(struct key_preparsed_payload *prep);
  39extern void user_free_preparse(struct key_preparsed_payload *prep);
  40extern int user_update(struct key *key, struct key_preparsed_payload *prep);
  41extern void user_revoke(struct key *key);
  42extern void user_destroy(struct key *key);
  43extern void user_describe(const struct key *user, struct seq_file *m);
  44extern long user_read(const struct key *key,
  45                      char __user *buffer, size_t buflen);
  46
  47static 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
  52static 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 */
  60