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
20struct kernel_pkey_query;
21struct kernel_pkey_params;
22
23/*
24 * Pre-parsed payload, used by key add, update and instantiate.
25 *
26 * This struct will be cleared and data and datalen will be set with the data
27 * and length parameters from the caller and quotalen will be set from
28 * def_datalen from the key type. Then if the preparse() op is provided by the
29 * key type, that will be called. Then the struct will be passed to the
30 * instantiate() or the update() op.
31 *
32 * If the preparse() op is given, the free_preparse() op will be called to
33 * clear the contents.
34 */
35struct key_preparsed_payload {
36 char *description; /* Proposed key description (or NULL) */
37 union key_payload payload; /* Proposed payload */
38 const void *data; /* Raw data */
39 size_t datalen; /* Raw datalen */
40 size_t quotalen; /* Quota length for proposed payload */
41 time64_t expiry; /* Expiry time of key */
42} __randomize_layout;
43
44typedef int (*request_key_actor_t)(struct key *auth_key, void *aux);
45
46/*
47 * Preparsed matching criterion.
48 */
49struct key_match_data {
50 /* Comparison function, defaults to exact description match, but can be
51 * overridden by type->match_preparse(). Should return true if a match
52 * is found and false if not.
53 */
54 bool (*cmp)(const struct key *key,
55 const struct key_match_data *match_data);
56
57 const void *raw_data; /* Raw match data */
58 void *preparsed; /* For ->match_preparse() to stash stuff */
59 unsigned lookup_type; /* Type of lookup for this search. */
60#define KEYRING_SEARCH_LOOKUP_DIRECT 0x0000 /* Direct lookup by description. */
61#define KEYRING_SEARCH_LOOKUP_ITERATE 0x0001 /* Iterative search. */
62};
63
64/*
65 * kernel managed key type definition
66 */
67struct key_type {
68 /* name of the type */
69 const char *name;
70
71 /* default payload length for quota precalculation (optional)
72 * - this can be used instead of calling key_payload_reserve(), that
73 * function only needs to be called if the real datalen is different
74 */
75 size_t def_datalen;
76
77 /* vet a description */
78 int (*vet_description)(const char *description);
79
80 /* Preparse the data blob from userspace that is to be the payload,
81 * generating a proposed description and payload that will be handed to
82 * the instantiate() and update() ops.
83 */
84 int (*preparse)(struct key_preparsed_payload *prep);
85
86 /* Free a preparse data structure.
87 */
88 void (*free_preparse)(struct key_preparsed_payload *prep);
89
90 /* instantiate a key of this type
91 * - this method should call key_payload_reserve() to determine if the
92 * user's quota will hold the payload
93 */
94 int (*instantiate)(struct key *key, struct key_preparsed_payload *prep);
95
96 /* update a key of this type (optional)
97 * - this method should call key_payload_reserve() to recalculate the
98 * quota consumption
99 * - the key must be locked against read when modifying
100 */
101 int (*update)(struct key *key, struct key_preparsed_payload *prep);
102
103 /* Preparse the data supplied to ->match() (optional). The
104 * data to be preparsed can be found in match_data->raw_data.
105 * The lookup type can also be set by this function.
106 */
107 int (*match_preparse)(struct key_match_data *match_data);
108
109 /* Free preparsed match data (optional). This should be supplied it
110 * ->match_preparse() is supplied. */
111 void (*match_free)(struct key_match_data *match_data);
112
113 /* clear some of the data from a key on revokation (optional)
114 * - the key's semaphore will be write-locked by the caller
115 */
116 void (*revoke)(struct key *key);
117
118 /* clear the data from a key (optional) */
119 void (*destroy)(struct key *key);
120
121 /* describe a key */
122 void (*describe)(const struct key *key, struct seq_file *p);
123
124 /* read a key's data (optional)
125 * - permission checks will be done by the caller
126 * - the key's semaphore will be readlocked by the caller
127 * - should return the amount of data that could be read, no matter how
128 * much is copied into the buffer
129 * - shouldn't do the copy if the buffer is NULL
130 */
131 long (*read)(const struct key *key, char __user *buffer, size_t buflen);
132
133 /* handle request_key() for this type instead of invoking
134 * /sbin/request-key (optional)
135 * - key is the key to instantiate
136 * - authkey is the authority to assume when instantiating this key
137 * - op is the operation to be done, usually "create"
138 * - the call must not return until the instantiation process has run
139 * its course
140 */
141 request_key_actor_t request_key;
142
143 /* Look up a keyring access restriction (optional)
144 *
145 * - NULL is a valid return value (meaning the requested restriction
146 * is known but will never block addition of a key)
147 * - should return -EINVAL if the restriction is unknown
148 */
149 struct key_restriction *(*lookup_restriction)(const char *params);
150
151 /* Asymmetric key accessor functions. */
152 int (*asym_query)(const struct kernel_pkey_params *params,
153 struct kernel_pkey_query *info);
154 int (*asym_eds_op)(struct kernel_pkey_params *params,
155 const void *in, void *out);
156 int (*asym_verify_signature)(struct kernel_pkey_params *params,
157 const void *in, const void *in2);
158
159 /* internal fields */
160 struct list_head link; /* link in types list */
161 struct lock_class_key lock_class; /* key->sem lock class */
162} __randomize_layout;
163
164extern struct key_type key_type_keyring;
165
166extern int register_key_type(struct key_type *ktype);
167extern void unregister_key_type(struct key_type *ktype);
168
169extern int key_payload_reserve(struct key *key, size_t datalen);
170extern int key_instantiate_and_link(struct key *key,
171 const void *data,
172 size_t datalen,
173 struct key *keyring,
174 struct key *authkey);
175extern int key_reject_and_link(struct key *key,
176 unsigned timeout,
177 unsigned error,
178 struct key *keyring,
179 struct key *authkey);
180extern void complete_request_key(struct key *authkey, int error);
181
182static inline int key_negate_and_link(struct key *key,
183 unsigned timeout,
184 struct key *keyring,
185 struct key *authkey)
186{
187 return key_reject_and_link(key, timeout, ENOKEY, keyring, authkey);
188}
189
190extern int generic_key_instantiate(struct key *key, struct key_preparsed_payload *prep);
191
192#endif /* CONFIG_KEYS */
193#endif /* _LINUX_KEY_TYPE_H */
194