1 /* SPDX-License-Identifier: GPL-2.0-or-later */
2 /* Definitions for key type implementations
3 *
4 * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
5 * Written by David Howells (dhowells@redhat.com)
6 */
7
8 #ifndef _LINUX_KEY_TYPE_H
9 #define _LINUX_KEY_TYPE_H
10
11 #include <linux/key.h>
12 #include <linux/errno.h>
13
14 #ifdef CONFIG_KEYS
15
16 struct kernel_pkey_query;
17 struct kernel_pkey_params;
18
19 /*
20 * Pre-parsed payload, used by key add, update and instantiate.
21 *
22 * This struct will be cleared and data and datalen will be set with the data
23 * and length parameters from the caller and quotalen will be set from
24 * def_datalen from the key type. Then if the preparse() op is provided by the
25 * key type, that will be called. Then the struct will be passed to the
26 * instantiate() or the update() op.
27 *
28 * If the preparse() op is given, the free_preparse() op will be called to
29 * clear the contents.
30 */
31 struct key_preparsed_payload {
32 char *description; /* Proposed key description (or NULL) */
33 union key_payload payload; /* Proposed payload */
34 const void *data; /* Raw data */
35 size_t datalen; /* Raw datalen */
36 size_t quotalen; /* Quota length for proposed payload */
37 time64_t expiry; /* Expiry time of key */
38 } __randomize_layout;
39
40 typedef int (*request_key_actor_t)(struct key *auth_key, void *aux);
41
42 /*
43 * Preparsed matching criterion.
44 */
45 struct key_match_data {
46 /* Comparison function, defaults to exact description match, but can be
47 * overridden by type->match_preparse(). Should return true if a match
48 * is found and false if not.
49 */
50 bool (*cmp)(const struct key *key,
51 const struct key_match_data *match_data);
52
53 const void *raw_data; /* Raw match data */
54 void *preparsed; /* For ->match_preparse() to stash stuff */
55 unsigned lookup_type; /* Type of lookup for this search. */
56 #define KEYRING_SEARCH_LOOKUP_DIRECT 0x0000 /* Direct lookup by description. */
57 #define KEYRING_SEARCH_LOOKUP_ITERATE 0x0001 /* Iterative search. */
58 };
59
60 /*
61 * kernel managed key type definition
62 */
63 struct key_type {
64 /* name of the type */
65 const char *name;
66
67 /* default payload length for quota precalculation (optional)
68 * - this can be used instead of calling key_payload_reserve(), that
69 * function only needs to be called if the real datalen is different
70 */
71 size_t def_datalen;
72
73 unsigned int flags;
74 #define KEY_TYPE_NET_DOMAIN 0x00000001 /* Keys of this type have a net namespace domain */
75
76 /* vet a description */
77 int (*vet_description)(const char *description);
78
79 /* Preparse the data blob from userspace that is to be the payload,
80 * generating a proposed description and payload that will be handed to
81 * the instantiate() and update() ops.
82 */
83 int (*preparse)(struct key_preparsed_payload *prep);
84
85 /* Free a preparse data structure.
86 */
87 void (*free_preparse)(struct key_preparsed_payload *prep);
88
89 /* instantiate a key of this type
90 * - this method should call key_payload_reserve() to determine if the
91 * user's quota will hold the payload
92 */
93 int (*instantiate)(struct key *key, struct key_preparsed_payload *prep);
94
95 /* update a key of this type (optional)
96 * - this method should call key_payload_reserve() to recalculate the
97 * quota consumption
98 * - the key must be locked against read when modifying
99 */
100 int (*update)(struct key *key, struct key_preparsed_payload *prep);
101
102 /* Preparse the data supplied to ->match() (optional). The
103 * data to be preparsed can be found in match_data->raw_data.
104 * The lookup type can also be set by this function.
105 */
106 int (*match_preparse)(struct key_match_data *match_data);
107
108 /* Free preparsed match data (optional). This should be supplied it
109 * ->match_preparse() is supplied. */
110 void (*match_free)(struct key_match_data *match_data);
111
112 /* clear some of the data from a key on revokation (optional)
113 * - the key's semaphore will be write-locked by the caller
114 */
115 void (*revoke)(struct key *key);
116
117 /* clear the data from a key (optional) */
118 void (*destroy)(struct key *key);
119
120 /* describe a key */
121 void (*describe)(const struct key *key, struct seq_file *p);
122
123 /* read a key's data (optional)
124 * - permission checks will be done by the caller
125 * - the key's semaphore will be readlocked by the caller
126 * - should return the amount of data that could be read, no matter how
127 * much is copied into the buffer
128 * - shouldn't do the copy if the buffer is NULL
129 */
130 long (*read)(const struct key *key, char *buffer, size_t buflen);
131
132 /* handle request_key() for this type instead of invoking
133 * /sbin/request-key (optional)
134 * - key is the key to instantiate
135 * - authkey is the authority to assume when instantiating this key
136 * - op is the operation to be done, usually "create"
137 * - the call must not return until the instantiation process has run
138 * its course
139 */
140 request_key_actor_t request_key;
141
142 /* Look up a keyring access restriction (optional)
143 *
144 * - NULL is a valid return value (meaning the requested restriction
145 * is known but will never block addition of a key)
146 * - should return -EINVAL if the restriction is unknown
147 */
148 struct key_restriction *(*lookup_restriction)(const char *params);
149
150 /* Asymmetric key accessor functions. */
151 int (*asym_query)(const struct kernel_pkey_params *params,
152 struct kernel_pkey_query *info);
153 int (*asym_eds_op)(struct kernel_pkey_params *params,
154 const void *in, void *out);
155 int (*asym_verify_signature)(struct kernel_pkey_params *params,
156 const void *in, const void *in2);
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 *authkey);
174 extern int key_reject_and_link(struct key *key,
175 unsigned timeout,
176 unsigned error,
177 struct key *keyring,
178 struct key *authkey);
179 extern void complete_request_key(struct key *authkey, int error);
180
181 static inline int key_negate_and_link(struct key *key,
182 unsigned timeout,
183 struct key *keyring,
184 struct key *authkey)
185 {
186 return key_reject_and_link(key, timeout, ENOKEY, keyring, authkey);
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 */