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/* 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) */
union key_payload payload; /* Proposed payload */
const void *data; /* Raw data */
size_t datalen; /* Raw datalen */
size_t quotalen; /* Quota length for proposed payload */
time64_t expiry; /* Expiry time of key */
} __randomize_layout;
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;
/* Look up a keyring access restriction (optional)
*
* - NULL is a valid return value (meaning the requested restriction
* is known but will never block addition of a key)
* - should return -EINVAL if the restriction is unknown
*/
struct key_restriction *(*lookup_restriction)(const char *params);
/* internal fields */
struct list_head link; /* link in types list */
struct lock_class_key lock_class; /* key->sem lock class */
} __randomize_layout;
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 */
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