LXR linux/include/linux/key-type.h

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