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 time64_t expiry; /* Expiry time of key */
48 } __randomize_layout;
49
50 typedef int (*request_key_actor_t)(struct key_construction *key,
51 const char *op, void *aux);
52
53 /*
54 * Preparsed matching criterion.
55 */
56 struct key_match_data {
57 /* Comparison function, defaults to exact description match, but can be
58 * overridden by type->match_preparse(). Should return true if a match
59 * is found and false if not.
60 */
61 bool (*cmp)(const struct key *key,
62 const struct key_match_data *match_data);
63
64 const void *raw_data; /* Raw match data */
65 void *preparsed; /* For ->match_preparse() to stash stuff */
66 unsigned lookup_type; /* Type of lookup for this search. */
67 #define KEYRING_SEARCH_LOOKUP_DIRECT 0x0000 /* Direct lookup by description. */
68 #define KEYRING_SEARCH_LOOKUP_ITERATE 0x0001 /* Iterative search. */
69 };
70
71 /*
72 * kernel managed key type definition
73 */
74 struct key_type {
75 /* name of the type */
76 const char *name;
77
78 /* default payload length for quota precalculation (optional)
79 * - this can be used instead of calling key_payload_reserve(), that
80 * function only needs to be called if the real datalen is different
81 */
82 size_t def_datalen;
83
84 /* vet a description */
85 int (*vet_description)(const char *description);
86
87 /* Preparse the data blob from userspace that is to be the payload,
88 * generating a proposed description and payload that will be handed to
89 * the instantiate() and update() ops.
90 */
91 int (*preparse)(struct key_preparsed_payload *prep);
92
93 /* Free a preparse data structure.
94 */
95 void (*free_preparse)(struct key_preparsed_payload *prep);
96
97 /* instantiate a key of this type
98 * - this method should call key_payload_reserve() to determine if the
99 * user's quota will hold the payload
100 */
101 int (*instantiate)(struct key *key, struct key_preparsed_payload *prep);
102
103 /* update a key of this type (optional)
104 * - this method should call key_payload_reserve() to recalculate the
105 * quota consumption
106 * - the key must be locked against read when modifying
107 */
108 int (*update)(struct key *key, struct key_preparsed_payload *prep);
109
110 /* Preparse the data supplied to ->match() (optional). The
111 * data to be preparsed can be found in match_data->raw_data.
112 * The lookup type can also be set by this function.
113 */
114 int (*match_preparse)(struct key_match_data *match_data);
115
116 /* Free preparsed match data (optional). This should be supplied it
117 * ->match_preparse() is supplied. */
118 void (*match_free)(struct key_match_data *match_data);
119
120 /* clear some of the data from a key on revokation (optional)
121 * - the key's semaphore will be write-locked by the caller
122 */
123 void (*revoke)(struct key *key);
124
125 /* clear the data from a key (optional) */
126 void (*destroy)(struct key *key);
127
128 /* describe a key */
129 void (*describe)(const struct key *key, struct seq_file *p);
130
131 /* read a key's data (optional)
132 * - permission checks will be done by the caller
133 * - the key's semaphore will be readlocked by the caller
134 * - should return the amount of data that could be read, no matter how
135 * much is copied into the buffer
136 * - shouldn't do the copy if the buffer is NULL
137 */
138 long (*read)(const struct key *key, char __user *buffer, size_t buflen);
139
140 /* handle request_key() for this type instead of invoking
141 * /sbin/request-key (optional)
142 * - key is the key to instantiate
143 * - authkey is the authority to assume when instantiating this key
144 * - op is the operation to be done, usually "create"
145 * - the call must not return until the instantiation process has run
146 * its course
147 */
148 request_key_actor_t request_key;
149
150 /* Look up a keyring access restriction (optional)
151 *
152 * - NULL is a valid return value (meaning the requested restriction
153 * is known but will never block addition of a key)
154 * - should return -EINVAL if the restriction is unknown
155 */
156 struct key_restriction *(*lookup_restriction)(const char *params);
157
158 /* internal fields */
159 struct list_head link; /* link in types list */
160 struct lock_class_key lock_class; /* key->sem lock class */
161 } __randomize_layout;
162
163 extern struct key_type key_type_keyring;
164
165 extern int register_key_type(struct key_type *ktype);
166 extern void unregister_key_type(struct key_type *ktype);
167
168 extern int key_payload_reserve(struct key *key, size_t datalen);
169 extern int key_instantiate_and_link(struct key *key,
170 const void *data,
171 size_t datalen,
172 struct key *keyring,
173 struct key *instkey);
174 extern int key_reject_and_link(struct key *key,
175 unsigned timeout,
176 unsigned error,
177 struct key *keyring,
178 struct key *instkey);
179 extern void complete_request_key(struct key_construction *cons, int error);
180
key_negate_and_link(struct key * key,unsigned timeout,struct key * keyring,struct key * instkey)181 static inline int key_negate_and_link(struct key *key,
182 unsigned timeout,
183 struct key *keyring,
184 struct key *instkey)
185 {
186 return key_reject_and_link(key, timeout, ENOKEY, keyring, instkey);
187 }
188
189 extern int generic_key_instantiate(struct key *key, struct key_preparsed_payload *prep);
190
191 #endif /* CONFIG_KEYS */
192 #endif /* _LINUX_KEY_TYPE_H */
193
