key-type.h

  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	/*
111	 * Free preparsed match data (optional).  This should be supplied if
112	 * ->match_preparse() is supplied.
113	 */
114	void (*match_free)(struct key_match_data *match_data);
115
116	/*
117	 * Clear some of the data from a key on revocation (optional).
118	 * - the key's semaphore will be write-locked by the caller
119	 */
120	void (*revoke)(struct key *key);
121
122	/* clear the data from a key (optional) */
123	void (*destroy)(struct key *key);
124
125	/* describe a key */
126	void (*describe)(const struct key *key, struct seq_file *p);
127
128	/* read a key's data (optional)
129	 * - permission checks will be done by the caller
130	 * - the key's semaphore will be readlocked by the caller
131	 * - should return the amount of data that could be read, no matter how
132	 *   much is copied into the buffer
133	 * - shouldn't do the copy if the buffer is NULL
134	 */
135	long (*read)(const struct key *key, char *buffer, size_t buflen);
136
137	/* handle request_key() for this type instead of invoking
138	 * /sbin/request-key (optional)
139	 * - key is the key to instantiate
140	 * - authkey is the authority to assume when instantiating this key
141	 * - op is the operation to be done, usually "create"
142	 * - the call must not return until the instantiation process has run
143	 *   its course
144	 */
145	request_key_actor_t request_key;
146
147	/* Look up a keyring access restriction (optional)
148	 *
149	 * - NULL is a valid return value (meaning the requested restriction
150	 *   is known but will never block addition of a key)
151	 * - should return -EINVAL if the restriction is unknown
152	 */
153	struct key_restriction *(*lookup_restriction)(const char *params);
154
155	/* Asymmetric key accessor functions. */
156	int (*asym_query)(const struct kernel_pkey_params *params,
157			  struct kernel_pkey_query *info);
158	int (*asym_eds_op)(struct kernel_pkey_params *params,
159			   const void *in, void *out);
160	int (*asym_verify_signature)(struct kernel_pkey_params *params,
161				     const void *in, const void *in2);
162
163	/* internal fields */
164	struct list_head	link;		/* link in types list */
165	struct lock_class_key	lock_class;	/* key->sem lock class */
166} __randomize_layout;
167
168extern struct key_type key_type_keyring;
169
170extern int register_key_type(struct key_type *ktype);
171extern void unregister_key_type(struct key_type *ktype);
172
173extern int key_payload_reserve(struct key *key, size_t datalen);
174extern int key_instantiate_and_link(struct key *key,
175				    const void *data,
176				    size_t datalen,
177				    struct key *keyring,
178				    struct key *authkey);
179extern int key_reject_and_link(struct key *key,
180			       unsigned timeout,
181			       unsigned error,
182			       struct key *keyring,
183			       struct key *authkey);
184extern void complete_request_key(struct key *authkey, int error);
185
186static inline int key_negate_and_link(struct key *key,
187				      unsigned timeout,
188				      struct key *keyring,
189				      struct key *authkey)
190{
191	return key_reject_and_link(key, timeout, ENOKEY, keyring, authkey);
192}
193
194extern int generic_key_instantiate(struct key *key, struct key_preparsed_payload *prep);
195
196#endif /* CONFIG_KEYS */
197#endif /* _LINUX_KEY_TYPE_H */