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 * Pre-parsed payload, used by key add, update and instantiate.
22 *
23 * This struct will be cleared and data and datalen will be set with the data
24 * and length parameters from the caller and quotalen will be set from
25 * def_datalen from the key type. Then if the preparse() op is provided by the
26 * key type, that will be called. Then the struct will be passed to the
27 * instantiate() or the update() op.
28 *
29 * If the preparse() op is given, the free_preparse() op will be called to
30 * clear the contents.
31 */
32 struct key_preparsed_payload {
33 char *description; /* Proposed key description (or NULL) */
34 union key_payload payload; /* Proposed payload */
35 const void *data; /* Raw data */
36 size_t datalen; /* Raw datalen */
37 size_t quotalen; /* Quota length for proposed payload */
38 time64_t expiry; /* Expiry time of key */
39 } __randomize_layout;
40
41 typedef int (*request_key_actor_t)(struct key *auth_key, void *aux);
42
43 /*
44 * Preparsed matching criterion.
45 */
46 struct key_match_data {
47 /* Comparison function, defaults to exact description match, but can be
48 * overridden by type->match_preparse(). Should return true if a match
49 * is found and false if not.
50 */
51 bool (*cmp)(const struct key *key,
52 const struct key_match_data *match_data);
53
54 const void *raw_data; /* Raw match data */
55 void *preparsed; /* For ->match_preparse() to stash stuff */
56 unsigned lookup_type; /* Type of lookup for this search. */
57 #define KEYRING_SEARCH_LOOKUP_DIRECT 0x0000 /* Direct lookup by description. */
58 #define KEYRING_SEARCH_LOOKUP_ITERATE 0x0001 /* Iterative search. */
59 };
60
61 /*
62 * kernel managed key type definition
63 */
64 struct key_type {
65 /* name of the type */
66 const char *name;
67
68 /* default payload length for quota precalculation (optional)
69 * - this can be used instead of calling key_payload_reserve(), that
70 * function only needs to be called if the real datalen is different
71 */
72 size_t def_datalen;
73
74 /* vet a description */
75 int (*vet_description)(const char *description);
76
77 /* Preparse the data blob from userspace that is to be the payload,
78 * generating a proposed description and payload that will be handed to
79 * the instantiate() and update() ops.
80 */
81 int (*preparse)(struct key_preparsed_payload *prep);
82
83 /* Free a preparse data structure.
84 */
85 void (*free_preparse)(struct key_preparsed_payload *prep);
86
87 /* instantiate a key of this type
88 * - this method should call key_payload_reserve() to determine if the
89 * user's quota will hold the payload
90 */
91 int (*instantiate)(struct key *key, struct key_preparsed_payload *prep);
92
93 /* update a key of this type (optional)
94 * - this method should call key_payload_reserve() to recalculate the
95 * quota consumption
96 * - the key must be locked against read when modifying
97 */
98 int (*update)(struct key *key, struct key_preparsed_payload *prep);
99
100 /* Preparse the data supplied to ->match() (optional). The
101 * data to be preparsed can be found in match_data->raw_data.
102 * The lookup type can also be set by this function.
103 */
104 int (*match_preparse)(struct key_match_data *match_data);
105
106 /* Free preparsed match data (optional). This should be supplied it
107 * ->match_preparse() is supplied. */
108 void (*match_free)(struct key_match_data *match_data);
109
110 /* clear some of the data from a key on revokation (optional)
111 * - the key's semaphore will be write-locked by the caller
112 */
113 void (*revoke)(struct key *key);
114
115 /* clear the data from a key (optional) */
116 void (*destroy)(struct key *key);
117
118 /* describe a key */
119 void (*describe)(const struct key *key, struct seq_file *p);
120
121 /* read a key's data (optional)
122 * - permission checks will be done by the caller
123 * - the key's semaphore will be readlocked by the caller
124 * - should return the amount of data that could be read, no matter how
125 * much is copied into the buffer
126 * - shouldn't do the copy if the buffer is NULL
127 */
128 long (*read)(const struct key *key, char *buffer, size_t buflen);
129
130 /* handle request_key() for this type instead of invoking
131 * /sbin/request-key (optional)
132 * - key is the key to instantiate
133 * - authkey is the authority to assume when instantiating this key
134 * - op is the operation to be done, usually "create"
135 * - the call must not return until the instantiation process has run
136 * its course
137 */
138 request_key_actor_t request_key;
139
140 /* Look up a keyring access restriction (optional)
141 *
142 * - NULL is a valid return value (meaning the requested restriction
143 * is known but will never block addition of a key)
144 * - should return -EINVAL if the restriction is unknown
145 */
146 struct key_restriction *(*lookup_restriction)(const char *params);
147
148 /* internal fields */
149 struct list_head link; /* link in types list */
150 struct lock_class_key lock_class; /* key->sem lock class */
151 } __randomize_layout;
152
153 extern struct key_type key_type_keyring;
154
155 extern int register_key_type(struct key_type *ktype);
156 extern void unregister_key_type(struct key_type *ktype);
157
158 extern int key_payload_reserve(struct key *key, size_t datalen);
159 extern int key_instantiate_and_link(struct key *key,
160 const void *data,
161 size_t datalen,
162 struct key *keyring,
163 struct key *authkey);
164 extern int key_reject_and_link(struct key *key,
165 unsigned timeout,
166 unsigned error,
167 struct key *keyring,
168 struct key *authkey);
169 extern void complete_request_key(struct key *authkey, int error);
170
key_negate_and_link(struct key * key,unsigned timeout,struct key * keyring,struct key * authkey)171 static inline int key_negate_and_link(struct key *key,
172 unsigned timeout,
173 struct key *keyring,
174 struct key *authkey)
175 {
176 return key_reject_and_link(key, timeout, ENOKEY, keyring, authkey);
177 }
178
179 extern int generic_key_instantiate(struct key *key, struct key_preparsed_payload *prep);
180
181 #endif /* CONFIG_KEYS */
182 #endif /* _LINUX_KEY_TYPE_H */
183