[linux-2.6-block.git] / include / linux / key-type.h

/* Definitions for key type implementations
 *
 * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
 * Written by David Howells (dhowells@redhat.com)
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public Licence
 * as published by the Free Software Foundation; either version
 * 2 of the Licence, or (at your option) any later version.
 */

#ifndef _LINUX_KEY_TYPE_H
#define _LINUX_KEY_TYPE_H

#include <linux/key.h>
#include <linux/errno.h>

#ifdef CONFIG_KEYS

/*
 * key under-construction record
 * - passed to the request_key actor if supplied
 */
struct key_construction {
	struct key	*key;	/* key being constructed */
	struct key	*authkey;/* authorisation for key being constructed */
};

/*
 * Pre-parsed payload, used by key add, update and instantiate.
 *
 * This struct will be cleared and data and datalen will be set with the data
 * and length parameters from the caller and quotalen will be set from
 * def_datalen from the key type.  Then if the preparse() op is provided by the
 * key type, that will be called.  Then the struct will be passed to the
 * instantiate() or the update() op.
 *
 * If the preparse() op is given, the free_preparse() op will be called to
 * clear the contents.
 */
struct key_preparsed_payload {
	char		*description;	/* Proposed key description (or NULL) */
	void		*type_data[2];	/* Private key-type data */
	void		*payload[2];	/* Proposed payload */
	const void	*data;		/* Raw data */
	size_t		datalen;	/* Raw datalen */
	size_t		quotalen;	/* Quota length for proposed payload */
	time_t		expiry;		/* Expiry time of key */
	bool		trusted;	/* True if key is trusted */
};

typedef int (*request_key_actor_t)(struct key_construction *key,
				   const char *op, void *aux);

/*
 * Preparsed matching criterion.
 */
struct key_match_data {
	/* Comparison function, defaults to exact description match, but can be
	 * overridden by type->match_preparse().  Should return true if a match
	 * is found and false if not.
	 */
	bool (*cmp)(const struct key *key,
		    const struct key_match_data *match_data);

	const void	*raw_data;	/* Raw match data */
	void		*preparsed;	/* For ->match_preparse() to stash stuff */
	unsigned	lookup_type;	/* Type of lookup for this search. */
#define KEYRING_SEARCH_LOOKUP_DIRECT	0x0000	/* Direct lookup by description. */
#define KEYRING_SEARCH_LOOKUP_ITERATE	0x0001	/* Iterative search. */
};

/*
 * kernel managed key type definition
 */
struct key_type {
	/* name of the type */
	const char *name;

	/* default payload length for quota precalculation (optional)
	 * - this can be used instead of calling key_payload_reserve(), that
	 *   function only needs to be called if the real datalen is different
	 */
	size_t def_datalen;

	/* vet a description */
	int (*vet_description)(const char *description);

	/* Preparse the data blob from userspace that is to be the payload,
	 * generating a proposed description and payload that will be handed to
	 * the instantiate() and update() ops.
	 */
	int (*preparse)(struct key_preparsed_payload *prep);

	/* Free a preparse data structure.
	 */
	void (*free_preparse)(struct key_preparsed_payload *prep);

	/* instantiate a key of this type
	 * - this method should call key_payload_reserve() to determine if the
	 *   user's quota will hold the payload
	 */
	int (*instantiate)(struct key *key, struct key_preparsed_payload *prep);

	/* update a key of this type (optional)
	 * - this method should call key_payload_reserve() to recalculate the
	 *   quota consumption
	 * - the key must be locked against read when modifying
	 */
	int (*update)(struct key *key, struct key_preparsed_payload *prep);

	/* Preparse the data supplied to ->match() (optional).  The
	 * data to be preparsed can be found in match_data->raw_data.
	 * The lookup type can also be set by this function.
	 */
	int (*match_preparse)(struct key_match_data *match_data);

	/* Free preparsed match data (optional).  This should be supplied it
	 * ->match_preparse() is supplied. */
	void (*match_free)(struct key_match_data *match_data);

	/* clear some of the data from a key on revokation (optional)
	 * - the key's semaphore will be write-locked by the caller
	 */
	void (*revoke)(struct key *key);

	/* clear the data from a key (optional) */
	void (*destroy)(struct key *key);

	/* describe a key */
	void (*describe)(const struct key *key, struct seq_file *p);

	/* read a key's data (optional)
	 * - permission checks will be done by the caller
	 * - the key's semaphore will be readlocked by the caller
	 * - should return the amount of data that could be read, no matter how
	 *   much is copied into the buffer
	 * - shouldn't do the copy if the buffer is NULL
	 */
	long (*read)(const struct key *key, char __user *buffer, size_t buflen);

	/* handle request_key() for this type instead of invoking
	 * /sbin/request-key (optional)
	 * - key is the key to instantiate
	 * - authkey is the authority to assume when instantiating this key
	 * - op is the operation to be done, usually "create"
	 * - the call must not return until the instantiation process has run
	 *   its course
	 */
	request_key_actor_t request_key;

	/* internal fields */
	struct list_head	link;		/* link in types list */
	struct lock_class_key	lock_class;	/* key->sem lock class */
};

extern struct key_type key_type_keyring;

extern int register_key_type(struct key_type *ktype);
extern void unregister_key_type(struct key_type *ktype);

extern int key_payload_reserve(struct key *key, size_t datalen);
extern int key_instantiate_and_link(struct key *key,
				    const void *data,
				    size_t datalen,
				    struct key *keyring,
				    struct key *instkey);
extern int key_reject_and_link(struct key *key,
			       unsigned timeout,
			       unsigned error,
			       struct key *keyring,
			       struct key *instkey);
extern void complete_request_key(struct key_construction *cons, int error);

static inline int key_negate_and_link(struct key *key,
				      unsigned timeout,
				      struct key *keyring,
				      struct key *instkey)
{
	return key_reject_and_link(key, timeout, ENOKEY, keyring, instkey);
}

extern int generic_key_instantiate(struct key *key, struct key_preparsed_payload *prep);

#endif /* CONFIG_KEYS */
#endif /* _LINUX_KEY_TYPE_H */
Commit	Line	Data
76181c13 DH	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>
5935e6dc	16	#include <linux/errno.h>
76181c13 DH	17
	18	#ifdef CONFIG_KEYS
	19
	20	/*
	21	* key under-construction record
	22	* - passed to the request_key actor if supplied
	23	*/
	24	struct key_construction {
	25	struct key key; / key being constructed */
	26	struct key authkey;/ authorisation for key being constructed */
	27	};
	28
cf7f601c DH	29	/*
	30	* Pre-parsed payload, used by key add, update and instantiate.
	31	*
	32	* This struct will be cleared and data and datalen will be set with the data
	33	* and length parameters from the caller and quotalen will be set from
	34	* def_datalen from the key type. Then if the preparse() op is provided by the
	35	* key type, that will be called. Then the struct will be passed to the
	36	* instantiate() or the update() op.
	37	*
	38	* If the preparse() op is given, the free_preparse() op will be called to
	39	* clear the contents.
	40	*/
	41	struct key_preparsed_payload {
	42	char description; / Proposed key description (or NULL) */
	43	void type_data[2]; / Private key-type data */
fc7c70e0	44	void payload[2]; / Proposed payload */
cf7f601c DH	45	const void data; / Raw data */
	46	size_t datalen; /* Raw datalen */
	47	size_t quotalen; /* Quota length for proposed payload */
7dfa0ca6	48	time_t expiry; /* Expiry time of key */
008643b8	49	bool trusted; /* True if key is trusted */
cf7f601c DH	50	};
cf7f601c DH	51
76181c13 DH	52	typedef int (request_key_actor_t)(struct key_construction key,
	53	const char op, void aux);
	54
46291959 DH	55	/*
	56	* Preparsed matching criterion.
	57	*/
	58	struct key_match_data {
0c903ab6 DH	59	/* Comparison function, defaults to exact description match, but can be
	60	* overridden by type->match_preparse(). Should return true if a match
	61	* is found and false if not.
	62	*/
	63	bool (cmp)(const struct key key,
	64	const struct key_match_data *match_data);
46291959 DH	65
	66	const void raw_data; / Raw match data */
	67	void preparsed; / For ->match_preparse() to stash stuff */
	68	unsigned lookup_type; /* Type of lookup for this search. */
	69	#define KEYRING_SEARCH_LOOKUP_DIRECT 0x0000 /* Direct lookup by description. */
	70	#define KEYRING_SEARCH_LOOKUP_ITERATE 0x0001 /* Iterative search. */
	71	};
	72
76181c13 DH	73	/*
	74	* kernel managed key type definition
	75	*/
	76	struct key_type {
	77	/* name of the type */
	78	const char *name;
	79
	80	/* default payload length for quota precalculation (optional)
	81	* - this can be used instead of calling key_payload_reserve(), that
	82	* function only needs to be called if the real datalen is different
	83	*/
	84	size_t def_datalen;
	85
b9fffa38 DH	86	/* vet a description */
	87	int (vet_description)(const char description);
	88
cf7f601c DH	89	/* Preparse the data blob from userspace that is to be the payload,
	90	* generating a proposed description and payload that will be handed to
	91	* the instantiate() and update() ops.
	92	*/
	93	int (preparse)(struct key_preparsed_payload prep);
	94
	95	/* Free a preparse data structure.
	96	*/
	97	void (free_preparse)(struct key_preparsed_payload prep);
	98
76181c13 DH	99	/* instantiate a key of this type
	100	* - this method should call key_payload_reserve() to determine if the
	101	* user's quota will hold the payload
	102	*/
cf7f601c	103	int (instantiate)(struct key key, struct key_preparsed_payload *prep);
76181c13 DH	104
	105	/* update a key of this type (optional)
	106	* - this method should call key_payload_reserve() to recalculate the
	107	* quota consumption
	108	* - the key must be locked against read when modifying
	109	*/
cf7f601c	110	int (update)(struct key key, struct key_preparsed_payload *prep);
76181c13	111
46291959 DH	112	/* Preparse the data supplied to ->match() (optional). The
	113	* data to be preparsed can be found in match_data->raw_data.
	114	* The lookup type can also be set by this function.
	115	*/
	116	int (match_preparse)(struct key_match_data match_data);
	117
46291959 DH	118	/* Free preparsed match data (optional). This should be supplied it
	119	* ->match_preparse() is supplied. */
	120	void (match_free)(struct key_match_data match_data);
76181c13 DH	121
	122	/* clear some of the data from a key on revokation (optional)
	123	* - the key's semaphore will be write-locked by the caller
	124	*/
	125	void (revoke)(struct key key);
	126
	127	/* clear the data from a key (optional) */
	128	void (destroy)(struct key key);
	129
	130	/* describe a key */
	131	void (describe)(const struct key key, struct seq_file *p);
	132
	133	/* read a key's data (optional)
	134	* - permission checks will be done by the caller
	135	* - the key's semaphore will be readlocked by the caller
	136	* - should return the amount of data that could be read, no matter how
	137	* much is copied into the buffer
	138	* - shouldn't do the copy if the buffer is NULL
	139	*/
	140	long (read)(const struct key key, char __user *buffer, size_t buflen);
	141
	142	/* handle request_key() for this type instead of invoking
	143	* /sbin/request-key (optional)
	144	* - key is the key to instantiate
	145	* - authkey is the authority to assume when instantiating this key
	146	* - op is the operation to be done, usually "create"
	147	* - the call must not return until the instantiation process has run
	148	* its course
	149	*/
	150	request_key_actor_t request_key;
	151
	152	/* internal fields */
	153	struct list_head link; /* link in types list */
7845bc39	154	struct lock_class_key lock_class; /* key->sem lock class */
76181c13 DH	155	};
	156
	157	extern struct key_type key_type_keyring;
	158
	159	extern int register_key_type(struct key_type *ktype);
	160	extern void unregister_key_type(struct key_type *ktype);
	161
	162	extern int key_payload_reserve(struct key *key, size_t datalen);
	163	extern int key_instantiate_and_link(struct key *key,
	164	const void *data,
	165	size_t datalen,
	166	struct key *keyring,
	167	struct key *instkey);
fdd1b945	168	extern int key_reject_and_link(struct key *key,
76181c13	169	unsigned timeout,
fdd1b945	170	unsigned error,
76181c13 DH	171	struct key *keyring,
	172	struct key *instkey);
	173	extern void complete_request_key(struct key_construction *cons, int error);
	174
fdd1b945 DH	175	static inline int key_negate_and_link(struct key *key,
	176	unsigned timeout,
	177	struct key *keyring,
	178	struct key *instkey)
	179	{
	180	return key_reject_and_link(key, timeout, ENOKEY, keyring, instkey);
	181	}
	182
6a09d17b DH	183	extern int generic_key_instantiate(struct key key, struct key_preparsed_payload prep);
6a09d17b DH	184
76181c13 DH	185	#endif /* CONFIG_KEYS */
76181c13 DH	186	#endif /* _LINUX_KEY_TYPE_H */