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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 */