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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
29/*
30 * Pre-parsed payload, used by key add, update and instantiate.
31 *
32 * This struct will be cleared and data and datalen will be set with the data
33 * and length parameters from the caller and quotalen will be set from
34 * def_datalen from the key type. Then if the preparse() op is provided by the
35 * key type, that will be called. Then the struct will be passed to the
36 * instantiate() or the update() op.
37 *
38 * If the preparse() op is given, the free_preparse() op will be called to
39 * clear the contents.
40 */
41struct key_preparsed_payload {
42 char *description; /* Proposed key description (or NULL) */
43 void *type_data[2]; /* Private key-type data */
44 void *payload; /* Proposed payload */
45 const void *data; /* Raw data */
46 size_t datalen; /* Raw datalen */
47 size_t quotalen; /* Quota length for proposed payload */
48};
49
50typedef int (*request_key_actor_t)(struct key_construction *key,
51 const char *op, void *aux);
52
53/*
54 * kernel managed key type definition
55 */
56struct key_type {
57 /* name of the type */
58 const char *name;
59
60 /* default payload length for quota precalculation (optional)
61 * - this can be used instead of calling key_payload_reserve(), that
62 * function only needs to be called if the real datalen is different
63 */
64 size_t def_datalen;
65
66 /* vet a description */
67 int (*vet_description)(const char *description);
68
69 /* Preparse the data blob from userspace that is to be the payload,
70 * generating a proposed description and payload that will be handed to
71 * the instantiate() and update() ops.
72 */
73 int (*preparse)(struct key_preparsed_payload *prep);
74
75 /* Free a preparse data structure.
76 */
77 void (*free_preparse)(struct key_preparsed_payload *prep);
78
79 /* instantiate a key of this type
80 * - this method should call key_payload_reserve() to determine if the
81 * user's quota will hold the payload
82 */
83 int (*instantiate)(struct key *key, struct key_preparsed_payload *prep);
84
85 /* update a key of this type (optional)
86 * - this method should call key_payload_reserve() to recalculate the
87 * quota consumption
88 * - the key must be locked against read when modifying
89 */
90 int (*update)(struct key *key, struct key_preparsed_payload *prep);
91
92 /* match a key against a description */
93 int (*match)(const struct key *key, const void *desc);
94
95 /* clear some of the data from a key on revokation (optional)
96 * - the key's semaphore will be write-locked by the caller
97 */
98 void (*revoke)(struct key *key);
99
100 /* clear the data from a key (optional) */
101 void (*destroy)(struct key *key);
102
103 /* describe a key */
104 void (*describe)(const struct key *key, struct seq_file *p);
105
106 /* read a key's data (optional)
107 * - permission checks will be done by the caller
108 * - the key's semaphore will be readlocked by the caller
109 * - should return the amount of data that could be read, no matter how
110 * much is copied into the buffer
111 * - shouldn't do the copy if the buffer is NULL
112 */
113 long (*read)(const struct key *key, char __user *buffer, size_t buflen);
114
115 /* handle request_key() for this type instead of invoking
116 * /sbin/request-key (optional)
117 * - key is the key to instantiate
118 * - authkey is the authority to assume when instantiating this key
119 * - op is the operation to be done, usually "create"
120 * - the call must not return until the instantiation process has run
121 * its course
122 */
123 request_key_actor_t request_key;
124
125 /* internal fields */
126 struct list_head link; /* link in types list */
127 struct lock_class_key lock_class; /* key->sem lock class */
128};
129
130extern struct key_type key_type_keyring;
131
132extern int register_key_type(struct key_type *ktype);
133extern void unregister_key_type(struct key_type *ktype);
134
135extern int key_payload_reserve(struct key *key, size_t datalen);
136extern int key_instantiate_and_link(struct key *key,
137 const void *data,
138 size_t datalen,
139 struct key *keyring,
140 struct key *instkey);
141extern int key_reject_and_link(struct key *key,
142 unsigned timeout,
143 unsigned error,
144 struct key *keyring,
145 struct key *instkey);
146extern void complete_request_key(struct key_construction *cons, int error);
147
148static inline int key_negate_and_link(struct key *key,
149 unsigned timeout,
150 struct key *keyring,
151 struct key *instkey)
152{
153 return key_reject_and_link(key, timeout, ENOKEY, keyring, instkey);
154}
155
156#endif /* CONFIG_KEYS */
157#endif /* _LINUX_KEY_TYPE_H */