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 	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 
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 	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 
165 extern struct key_type key_type_keyring;
166 
167 extern int register_key_type(struct key_type *ktype);
168 extern void unregister_key_type(struct key_type *ktype);
169 
170 extern int key_payload_reserve(struct key *key, size_t datalen);
171 extern int key_instantiate_and_link(struct key *key,
172 				    const void *data,
173 				    size_t datalen,
174 				    struct key *keyring,
175 				    struct key *authkey);
176 extern int key_reject_and_link(struct key *key,
177 			       unsigned timeout,
178 			       unsigned error,
179 			       struct key *keyring,
180 			       struct key *authkey);
181 extern void complete_request_key(struct key *authkey, int error);
182 
key_negate_and_link(struct key * key,unsigned timeout,struct key * keyring,struct key * authkey)183 static 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 
191 extern int generic_key_instantiate(struct key *key, struct key_preparsed_payload *prep);
192 
193 #endif /* CONFIG_KEYS */
194 #endif /* _LINUX_KEY_TYPE_H */
195