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