1 /* SPDX-License-Identifier: GPL-2.0-or-later */
2 /* Asymmetric Public-key cryptography key type interface
3 *
4 * See Documentation/crypto/asymmetric-keys.txt
5 *
6 * Copyright (C) 2012 Red Hat, Inc. All Rights Reserved.
7 * Written by David Howells (dhowells@redhat.com)
8 */
9
10 #ifndef _KEYS_ASYMMETRIC_TYPE_H
11 #define _KEYS_ASYMMETRIC_TYPE_H
12
13 #include <linux/key-type.h>
14 #include <linux/verification.h>
15
16 extern struct key_type key_type_asymmetric;
17
18 /*
19 * The key payload is four words. The asymmetric-type key uses them as
20 * follows:
21 */
22 enum asymmetric_payload_bits {
23 asym_crypto, /* The data representing the key */
24 asym_subtype, /* Pointer to an asymmetric_key_subtype struct */
25 asym_key_ids, /* Pointer to an asymmetric_key_ids struct */
26 asym_auth /* The key's authorisation (signature, parent key ID) */
27 };
28
29 /*
30 * Identifiers for an asymmetric key ID. We have three ways of looking up a
31 * key derived from an X.509 certificate:
32 *
33 * (1) Serial Number & Issuer. Non-optional. This is the only valid way to
34 * map a PKCS#7 signature to an X.509 certificate.
35 *
36 * (2) Issuer & Subject Unique IDs. Optional. These were the original way to
37 * match X.509 certificates, but have fallen into disuse in favour of (3).
38 *
39 * (3) Auth & Subject Key Identifiers. Optional. SKIDs are only provided on
40 * CA keys that are intended to sign other keys, so don't appear in end
41 * user certificates unless forced.
42 *
43 * We could also support an PGP key identifier, which is just a SHA1 sum of the
44 * public key and certain parameters, but since we don't support PGP keys at
45 * the moment, we shall ignore those.
46 *
47 * What we actually do is provide a place where binary identifiers can be
48 * stashed and then compare against them when checking for an id match.
49 */
50 struct asymmetric_key_id {
51 unsigned short len;
52 unsigned char data[];
53 };
54
55 struct asymmetric_key_ids {
56 void *id[2];
57 };
58
59 extern bool asymmetric_key_id_same(const struct asymmetric_key_id *kid1,
60 const struct asymmetric_key_id *kid2);
61
62 extern bool asymmetric_key_id_partial(const struct asymmetric_key_id *kid1,
63 const struct asymmetric_key_id *kid2);
64
65 extern struct asymmetric_key_id *asymmetric_key_generate_id(const void *val_1,
66 size_t len_1,
67 const void *val_2,
68 size_t len_2);
69 static inline
70 const struct asymmetric_key_ids *asymmetric_key_ids(const struct key *key)
71 {
72 return key->payload.data[asym_key_ids];
73 }
74
75 extern struct key *find_asymmetric_key(struct key *keyring,
76 const struct asymmetric_key_id *id_0,
77 const struct asymmetric_key_id *id_1,
78 bool partial);
79
80 /*
81 * The payload is at the discretion of the subtype.
82 */
83
84 #endif /* _KEYS_ASYMMETRIC_TYPE_H */