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
16struct kernel_pkey_query;
17struct 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 */
31struct key_preparsed_payload {
32	const char	*orig_description; /* Actual or proposed description (maybe NULL) */
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
41typedef int (*request_key_actor_t)(struct key *auth_key, void *aux);
42
43/*
44 * Preparsed matching criterion.
45 */
46struct 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 */
64struct 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	unsigned int flags;
75#define KEY_TYPE_NET_DOMAIN	0x00000001 /* Keys of this type have a net namespace domain */
76#define KEY_TYPE_INSTANT_REAP	0x00000002 /* Keys of this type don't have a delay after expiring */
77
78	/* vet a description */
79	int (*vet_description)(const char *description);
80
81	/* Preparse the data blob from userspace that is to be the payload,
82	 * generating a proposed description and payload that will be handed to
83	 * the instantiate() and update() ops.
84	 */
85	int (*preparse)(struct key_preparsed_payload *prep);
86
87	/* Free a preparse data structure.
88	 */
89	void (*free_preparse)(struct key_preparsed_payload *prep);
90
91	/* instantiate a key of this type
92	 * - this method should call key_payload_reserve() to determine if the
93	 *   user's quota will hold the payload
94	 */
95	int (*instantiate)(struct key *key, struct key_preparsed_payload *prep);
96
97	/* update a key of this type (optional)
98	 * - this method should call key_payload_reserve() to recalculate the
99	 *   quota consumption
100	 * - the key must be locked against read when modifying
101	 */
102	int (*update)(struct key *key, struct key_preparsed_payload *prep);
103
104	/* Preparse the data supplied to ->match() (optional).  The
105	 * data to be preparsed can be found in match_data->raw_data.
106	 * The lookup type can also be set by this function.
107	 */
108	int (*match_preparse)(struct key_match_data *match_data);
109
110	/* Free preparsed match data (optional).  This should be supplied it
111	 * ->match_preparse() is supplied. */
112	void (*match_free)(struct key_match_data *match_data);
113
114	/* clear some of the data from a key on revokation (optional)
115	 * - the key's semaphore will be write-locked by the caller
116	 */
117	void (*revoke)(struct key *key);
118
119	/* clear the data from a key (optional) */
120	void (*destroy)(struct key *key);
121
122	/* describe a key */
123	void (*describe)(const struct key *key, struct seq_file *p);
124
125	/* read a key's data (optional)
126	 * - permission checks will be done by the caller
127	 * - the key's semaphore will be readlocked by the caller
128	 * - should return the amount of data that could be read, no matter how
129	 *   much is copied into the buffer
130	 * - shouldn't do the copy if the buffer is NULL
131	 */
132	long (*read)(const struct key *key, char *buffer, size_t buflen);
133
134	/* handle request_key() for this type instead of invoking
135	 * /sbin/request-key (optional)
136	 * - key is the key to instantiate
137	 * - authkey is the authority to assume when instantiating this key
138	 * - op is the operation to be done, usually "create"
139	 * - the call must not return until the instantiation process has run
140	 *   its course
141	 */
142	request_key_actor_t request_key;
143
144	/* Look up a keyring access restriction (optional)
145	 *
146	 * - NULL is a valid return value (meaning the requested restriction
147	 *   is known but will never block addition of a key)
148	 * - should return -EINVAL if the restriction is unknown
149	 */
150	struct key_restriction *(*lookup_restriction)(const char *params);
151
152	/* Asymmetric key accessor functions. */
153	int (*asym_query)(const struct kernel_pkey_params *params,
154			  struct kernel_pkey_query *info);
155	int (*asym_eds_op)(struct kernel_pkey_params *params,
156			   const void *in, void *out);
157	int (*asym_verify_signature)(struct kernel_pkey_params *params,
158				     const void *in, const void *in2);
159
160	/* internal fields */
161	struct list_head	link;		/* link in types list */
162	struct lock_class_key	lock_class;	/* key->sem lock class */
163} __randomize_layout;
164
165extern struct key_type key_type_keyring;
166
167extern int register_key_type(struct key_type *ktype);
168extern void unregister_key_type(struct key_type *ktype);
169
170extern int key_payload_reserve(struct key *key, size_t datalen);
171extern int key_instantiate_and_link(struct key *key,
172				    const void *data,
173				    size_t datalen,
174				    struct key *keyring,
175				    struct key *authkey);
176extern int key_reject_and_link(struct key *key,
177			       unsigned timeout,
178			       unsigned error,
179			       struct key *keyring,
180			       struct key *authkey);
181extern void complete_request_key(struct key *authkey, int error);
182
183static inline int key_negate_and_link(struct key *key,
184				      unsigned timeout,
185				      struct key *keyring,
186				      struct key *authkey)
187{
188	return key_reject_and_link(key, timeout, ENOKEY, keyring, authkey);
189}
190
191extern int generic_key_instantiate(struct key *key, struct key_preparsed_payload *prep);
192
193#endif /* CONFIG_KEYS */
194#endif /* _LINUX_KEY_TYPE_H */
195