1// SPDX-License-Identifier: GPL-2.0-or-later
2/* Signature verification with an asymmetric key
3 *
4 * See Documentation/crypto/asymmetric-keys.rst
5 *
6 * Copyright (C) 2012 Red Hat, Inc. All Rights Reserved.
7 * Written by David Howells (dhowells@redhat.com)
8 */
9
10#define pr_fmt(fmt) "SIG: "fmt
11#include <keys/asymmetric-subtype.h>
12#include <linux/export.h>
13#include <linux/err.h>
14#include <linux/slab.h>
15#include <linux/keyctl.h>
16#include <crypto/public_key.h>
17#include <keys/user-type.h>
18#include "asymmetric_keys.h"
19
20/*
21 * Destroy a public key signature.
22 */
23void public_key_signature_free(struct public_key_signature *sig)
24{
25 int i;
26
27 if (sig) {
28 for (i = 0; i < ARRAY_SIZE(sig->auth_ids); i++)
29 kfree(objp: sig->auth_ids[i]);
30 kfree(objp: sig->s);
31 kfree(objp: sig->digest);
32 kfree(objp: sig);
33 }
34}
35EXPORT_SYMBOL_GPL(public_key_signature_free);
36
37/**
38 * query_asymmetric_key - Get information about an asymmetric key.
39 * @params: Various parameters.
40 * @info: Where to put the information.
41 */
42int query_asymmetric_key(const struct kernel_pkey_params *params,
43 struct kernel_pkey_query *info)
44{
45 const struct asymmetric_key_subtype *subtype;
46 struct key *key = params->key;
47 int ret;
48
49 pr_devel("==>%s()\n", __func__);
50
51 if (key->type != &key_type_asymmetric)
52 return -EINVAL;
53 subtype = asymmetric_key_subtype(key);
54 if (!subtype ||
55 !key->payload.data[0])
56 return -EINVAL;
57 if (!subtype->query)
58 return -ENOTSUPP;
59
60 ret = subtype->query(params, info);
61
62 pr_devel("<==%s() = %d\n", __func__, ret);
63 return ret;
64}
65EXPORT_SYMBOL_GPL(query_asymmetric_key);
66
67/**
68 * verify_signature - Initiate the use of an asymmetric key to verify a signature
69 * @key: The asymmetric key to verify against
70 * @sig: The signature to check
71 *
72 * Returns 0 if successful or else an error.
73 */
74int verify_signature(const struct key *key,
75 const struct public_key_signature *sig)
76{
77 const struct asymmetric_key_subtype *subtype;
78 int ret;
79
80 pr_devel("==>%s()\n", __func__);
81
82 if (key->type != &key_type_asymmetric)
83 return -EINVAL;
84 subtype = asymmetric_key_subtype(key);
85 if (!subtype ||
86 !key->payload.data[0])
87 return -EINVAL;
88 if (!subtype->verify_signature)
89 return -ENOTSUPP;
90
91 ret = subtype->verify_signature(key, sig);
92
93 pr_devel("<==%s() = %d\n", __func__, ret);
94 return ret;
95}
96EXPORT_SYMBOL_GPL(verify_signature);
97