linux/include/keys/asymmetric-type.h
David Howells 3b76456317 KEYS: Allow authentication data to be stored in an asymmetric key
Allow authentication data to be stored in an asymmetric key in the 4th
element of the key payload and provide a way for it to be destroyed.

For the public key subtype, this will be a public_key_signature struct.

Signed-off-by: David Howells <dhowells@redhat.com>
2016-04-06 16:13:33 +01:00

83 lines
2.7 KiB
C

/* Asymmetric Public-key cryptography key type interface
*
* See Documentation/security/asymmetric-keys.txt
*
* Copyright (C) 2012 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 _KEYS_ASYMMETRIC_TYPE_H
#define _KEYS_ASYMMETRIC_TYPE_H
#include <linux/key-type.h>
extern struct key_type key_type_asymmetric;
/*
* The key payload is four words. The asymmetric-type key uses them as
* follows:
*/
enum asymmetric_payload_bits {
asym_crypto, /* The data representing the key */
asym_subtype, /* Pointer to an asymmetric_key_subtype struct */
asym_key_ids, /* Pointer to an asymmetric_key_ids struct */
asym_auth /* The key's authorisation (signature, parent key ID) */
};
/*
* Identifiers for an asymmetric key ID. We have three ways of looking up a
* key derived from an X.509 certificate:
*
* (1) Serial Number & Issuer. Non-optional. This is the only valid way to
* map a PKCS#7 signature to an X.509 certificate.
*
* (2) Issuer & Subject Unique IDs. Optional. These were the original way to
* match X.509 certificates, but have fallen into disuse in favour of (3).
*
* (3) Auth & Subject Key Identifiers. Optional. SKIDs are only provided on
* CA keys that are intended to sign other keys, so don't appear in end
* user certificates unless forced.
*
* We could also support an PGP key identifier, which is just a SHA1 sum of the
* public key and certain parameters, but since we don't support PGP keys at
* the moment, we shall ignore those.
*
* What we actually do is provide a place where binary identifiers can be
* stashed and then compare against them when checking for an id match.
*/
struct asymmetric_key_id {
unsigned short len;
unsigned char data[];
};
struct asymmetric_key_ids {
void *id[2];
};
extern bool asymmetric_key_id_same(const struct asymmetric_key_id *kid1,
const struct asymmetric_key_id *kid2);
extern bool asymmetric_key_id_partial(const struct asymmetric_key_id *kid1,
const struct asymmetric_key_id *kid2);
extern struct asymmetric_key_id *asymmetric_key_generate_id(const void *val_1,
size_t len_1,
const void *val_2,
size_t len_2);
static inline
const struct asymmetric_key_ids *asymmetric_key_ids(const struct key *key)
{
return key->payload.data[asym_key_ids];
}
/*
* The payload is at the discretion of the subtype.
*/
#endif /* _KEYS_ASYMMETRIC_TYPE_H */