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 */
23 struct key_construction {
24 struct key *key; /* key being constructed */
25 struct key *authkey;/* authorisation for key being constructed */
26 };
27
28 typedef int (*request_key_actor_t)(struct key_construction *key,
29 const char *op, void *aux);
30
31 /*
32 * kernel managed key type definition
33 */
34 struct 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 /* vet a description */
45 int (*vet_description)(const char *description);
46
47 /* instantiate a key of this type
48 * - this method should call key_payload_reserve() to determine if the
49 * user's quota will hold the payload
50 */
51 int (*instantiate)(struct key *key, const void *data, size_t datalen);
52
53 /* update a key of this type (optional)
54 * - this method should call key_payload_reserve() to recalculate the
55 * quota consumption
56 * - the key must be locked against read when modifying
57 */
58 int (*update)(struct key *key, const void *data, size_t datalen);
59
60 /* match a key against a description */
61 int (*match)(const struct key *key, const void *desc);
62
63 /* clear some of the data from a key on revokation (optional)
64 * - the key's semaphore will be write-locked by the caller
65 */
66 void (*revoke)(struct key *key);
67
68 /* clear the data from a key (optional) */
69 void (*destroy)(struct key *key);
70
71 /* describe a key */
72 void (*describe)(const struct key *key, struct seq_file *p);
73
74 /* read a key's data (optional)
75 * - permission checks will be done by the caller
76 * - the key's semaphore will be readlocked by the caller
77 * - should return the amount of data that could be read, no matter how
78 * much is copied into the buffer
79 * - shouldn't do the copy if the buffer is NULL
80 */
81 long (*read)(const struct key *key, char __user *buffer, size_t buflen);
82
83 /* handle request_key() for this type instead of invoking
84 * /sbin/request-key (optional)
85 * - key is the key to instantiate
86 * - authkey is the authority to assume when instantiating this key
87 * - op is the operation to be done, usually "create"
88 * - the call must not return until the instantiation process has run
89 * its course
90 */
91 request_key_actor_t request_key;
92
93 /* internal fields */
94 struct list_head link; /* link in types list */
95 struct lock_class_key lock_class; /* key->sem lock class */
96 };
97
98 extern struct key_type key_type_keyring;
99
100 extern int register_key_type(struct key_type *ktype);
101 extern void unregister_key_type(struct key_type *ktype);
102
103 extern int key_payload_reserve(struct key *key, size_t datalen);
104 extern int key_instantiate_and_link(struct key *key,
105 const void *data,
106 size_t datalen,
107 struct key *keyring,
108 struct key *instkey);
109 extern int key_reject_and_link(struct key *key,
110 unsigned timeout,
111 unsigned error,
112 struct key *keyring,
113 struct key *instkey);
114 extern void complete_request_key(struct key_construction *cons, int error);
115
key_negate_and_link(struct key * key,unsigned timeout,struct key * keyring,struct key * instkey)116 static inline int key_negate_and_link(struct key *key,
117 unsigned timeout,
118 struct key *keyring,
119 struct key *instkey)
120 {
121 return key_reject_and_link(key, timeout, ENOKEY, keyring, instkey);
122 }
123
124 #endif /* CONFIG_KEYS */
125 #endif /* _LINUX_KEY_TYPE_H */
126