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 */
24 struct 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 */
41 struct key_preparsed_payload {
42 char *description; /* Proposed key description (or NULL) */
43 union key_payload payload; /* Proposed payload */
44 const void *data; /* Raw data */
45 size_t datalen; /* Raw datalen */
46 size_t quotalen; /* Quota length for proposed payload */
47 time_t expiry; /* Expiry time of key */
48 bool trusted; /* True if key is trusted */
49 };
50
51 typedef int (*request_key_actor_t)(struct key_construction *key,
52 const char *op, void *aux);
53
54 /*
55 * Preparsed matching criterion.
56 */
57 struct key_match_data {
58 /* Comparison function, defaults to exact description match, but can be
59 * overridden by type->match_preparse(). Should return true if a match
60 * is found and false if not.
61 */
62 bool (*cmp)(const struct key *key,
63 const struct key_match_data *match_data);
64
65 const void *raw_data; /* Raw match data */
66 void *preparsed; /* For ->match_preparse() to stash stuff */
67 unsigned lookup_type; /* Type of lookup for this search. */
68 #define KEYRING_SEARCH_LOOKUP_DIRECT 0x0000 /* Direct lookup by description. */
69 #define KEYRING_SEARCH_LOOKUP_ITERATE 0x0001 /* Iterative search. */
70 };
71
72 /*
73 * kernel managed key type definition
74 */
75 struct key_type {
76 /* name of the type */
77 const char *name;
78
79 /* default payload length for quota precalculation (optional)
80 * - this can be used instead of calling key_payload_reserve(), that
81 * function only needs to be called if the real datalen is different
82 */
83 size_t def_datalen;
84
85 /* vet a description */
86 int (*vet_description)(const char *description);
87
88 /* Preparse the data blob from userspace that is to be the payload,
89 * generating a proposed description and payload that will be handed to
90 * the instantiate() and update() ops.
91 */
92 int (*preparse)(struct key_preparsed_payload *prep);
93
94 /* Free a preparse data structure.
95 */
96 void (*free_preparse)(struct key_preparsed_payload *prep);
97
98 /* instantiate a key of this type
99 * - this method should call key_payload_reserve() to determine if the
100 * user's quota will hold the payload
101 */
102 int (*instantiate)(struct key *key, struct key_preparsed_payload *prep);
103
104 /* update a key of this type (optional)
105 * - this method should call key_payload_reserve() to recalculate the
106 * quota consumption
107 * - the key must be locked against read when modifying
108 */
109 int (*update)(struct key *key, struct key_preparsed_payload *prep);
110
111 /* Preparse the data supplied to ->match() (optional). The
112 * data to be preparsed can be found in match_data->raw_data.
113 * The lookup type can also be set by this function.
114 */
115 int (*match_preparse)(struct key_match_data *match_data);
116
117 /* Free preparsed match data (optional). This should be supplied it
118 * ->match_preparse() is supplied. */
119 void (*match_free)(struct key_match_data *match_data);
120
121 /* clear some of the data from a key on revokation (optional)
122 * - the key's semaphore will be write-locked by the caller
123 */
124 void (*revoke)(struct key *key);
125
126 /* clear the data from a key (optional) */
127 void (*destroy)(struct key *key);
128
129 /* describe a key */
130 void (*describe)(const struct key *key, struct seq_file *p);
131
132 /* read a key's data (optional)
133 * - permission checks will be done by the caller
134 * - the key's semaphore will be readlocked by the caller
135 * - should return the amount of data that could be read, no matter how
136 * much is copied into the buffer
137 * - shouldn't do the copy if the buffer is NULL
138 */
139 long (*read)(const struct key *key, char __user *buffer, size_t buflen);
140
141 /* handle request_key() for this type instead of invoking
142 * /sbin/request-key (optional)
143 * - key is the key to instantiate
144 * - authkey is the authority to assume when instantiating this key
145 * - op is the operation to be done, usually "create"
146 * - the call must not return until the instantiation process has run
147 * its course
148 */
149 request_key_actor_t request_key;
150
151 /* internal fields */
152 struct list_head link; /* link in types list */
153 struct lock_class_key lock_class; /* key->sem lock class */
154 };
155
156 extern struct key_type key_type_keyring;
157
158 extern int register_key_type(struct key_type *ktype);
159 extern void unregister_key_type(struct key_type *ktype);
160
161 extern int key_payload_reserve(struct key *key, size_t datalen);
162 extern int key_instantiate_and_link(struct key *key,
163 const void *data,
164 size_t datalen,
165 struct key *keyring,
166 struct key *instkey);
167 extern int key_reject_and_link(struct key *key,
168 unsigned timeout,
169 unsigned error,
170 struct key *keyring,
171 struct key *instkey);
172 extern void complete_request_key(struct key_construction *cons, int error);
173
key_negate_and_link(struct key * key,unsigned timeout,struct key * keyring,struct key * instkey)174 static inline int key_negate_and_link(struct key *key,
175 unsigned timeout,
176 struct key *keyring,
177 struct key *instkey)
178 {
179 return key_reject_and_link(key, timeout, ENOKEY, keyring, instkey);
180 }
181
182 extern int generic_key_instantiate(struct key *key, struct key_preparsed_payload *prep);
183
184 #endif /* CONFIG_KEYS */
185 #endif /* _LINUX_KEY_TYPE_H */
186