linux/include/linux/key-type.h
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   1/* Definitions for key type implementations
   2 *
   3 * Copyright (C) 2007 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 Licence
   8 * as published by the Free Software Foundation; either version
   9 * 2 of the Licence, or (at your option) any later version.
  10 */
  11
  12#ifndef _LINUX_KEY_TYPE_H
  13#define _LINUX_KEY_TYPE_H
  14
  15#include <linux/key.h>
  16#include <linux/errno.h>
  17
  18#ifdef CONFIG_KEYS
  19
  20/*
  21 * key under-construction record
  22 * - passed to the request_key actor if supplied
  23 */
  24struct key_construction {
  25        struct key      *key;   /* key being constructed */
  26        struct key      *authkey;/* authorisation for key being constructed */
  27};
  28
  29typedef int (*request_key_actor_t)(struct key_construction *key,
  30                                   const char *op, void *aux);
  31
  32/*
  33 * kernel managed key type definition
  34 */
  35struct key_type {
  36        /* name of the type */
  37        const char *name;
  38
  39        /* default payload length for quota precalculation (optional)
  40         * - this can be used instead of calling key_payload_reserve(), that
  41         *   function only needs to be called if the real datalen is different
  42         */
  43        size_t def_datalen;
  44
  45        /* vet a description */
  46        int (*vet_description)(const char *description);
  47
  48        /* instantiate a key of this type
  49         * - this method should call key_payload_reserve() to determine if the
  50         *   user's quota will hold the payload
  51         */
  52        int (*instantiate)(struct key *key, const void *data, size_t datalen);
  53
  54        /* update a key of this type (optional)
  55         * - this method should call key_payload_reserve() to recalculate the
  56         *   quota consumption
  57         * - the key must be locked against read when modifying
  58         */
  59        int (*update)(struct key *key, const void *data, size_t datalen);
  60
  61        /* match a key against a description */
  62        int (*match)(const struct key *key, const void *desc);
  63
  64        /* clear some of the data from a key on revokation (optional)
  65         * - the key's semaphore will be write-locked by the caller
  66         */
  67        void (*revoke)(struct key *key);
  68
  69        /* clear the data from a key (optional) */
  70        void (*destroy)(struct key *key);
  71
  72        /* describe a key */
  73        void (*describe)(const struct key *key, struct seq_file *p);
  74
  75        /* read a key's data (optional)
  76         * - permission checks will be done by the caller
  77         * - the key's semaphore will be readlocked by the caller
  78         * - should return the amount of data that could be read, no matter how
  79         *   much is copied into the buffer
  80         * - shouldn't do the copy if the buffer is NULL
  81         */
  82        long (*read)(const struct key *key, char __user *buffer, size_t buflen);
  83
  84        /* handle request_key() for this type instead of invoking
  85         * /sbin/request-key (optional)
  86         * - key is the key to instantiate
  87         * - authkey is the authority to assume when instantiating this key
  88         * - op is the operation to be done, usually "create"
  89         * - the call must not return until the instantiation process has run
  90         *   its course
  91         */
  92        request_key_actor_t request_key;
  93
  94        /* internal fields */
  95        struct list_head        link;           /* link in types list */
  96        struct lock_class_key   lock_class;     /* key->sem lock class */
  97};
  98
  99extern struct key_type key_type_keyring;
 100
 101extern int register_key_type(struct key_type *ktype);
 102extern void unregister_key_type(struct key_type *ktype);
 103
 104extern int key_payload_reserve(struct key *key, size_t datalen);
 105extern int key_instantiate_and_link(struct key *key,
 106                                    const void *data,
 107                                    size_t datalen,
 108                                    struct key *keyring,
 109                                    struct key *instkey);
 110extern int key_reject_and_link(struct key *key,
 111                               unsigned timeout,
 112                               unsigned error,
 113                               struct key *keyring,
 114                               struct key *instkey);
 115extern void complete_request_key(struct key_construction *cons, int error);
 116
 117static inline int key_negate_and_link(struct key *key,
 118                                      unsigned timeout,
 119                                      struct key *keyring,
 120                                      struct key *instkey)
 121{
 122        return key_reject_and_link(key, timeout, ENOKEY, keyring, instkey);
 123}
 124
 125#endif /* CONFIG_KEYS */
 126#endif /* _LINUX_KEY_TYPE_H */
 127
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