aboutsummaryrefslogtreecommitdiffstats
path: root/crypto/rsa_helper.c
blob: d226f48d090767afb6fc588ac7829b09f9509cf3 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
/*
 * RSA key extract helper
 *
 * Copyright (c) 2015, Intel Corporation
 * Authors: Tadeusz Struk <tadeusz.struk@intel.com>
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by the Free
 * Software Foundation; either version 2 of the License, or (at your option)
 * any later version.
 *
 */
#include <linux/kernel.h>
#include <linux/export.h>
#include <linux/err.h>
#include <linux/fips.h>
#include <crypto/internal/rsa.h>
#include "rsapubkey-asn1.h"
#include "rsaprivkey-asn1.h"

int rsa_get_n(void *context, size_t hdrlen, unsigned char tag,
	      const void *value, size_t vlen)
{
	struct rsa_key *key = context;

	key->n = mpi_read_raw_data(value, vlen);

	if (!key->n)
		return -ENOMEM;

	/* In FIPS mode only allow key size 2K & 3K */
	if (fips_enabled && (mpi_get_size(key->n) != 256 &&
			     mpi_get_size(key->n) != 384)) {
		pr_err("RSA: key size not allowed in FIPS mode\n");
		mpi_free(key->n);
		key->n = NULL;
		return -EINVAL;
	}
	return 0;
}

int rsa_get_e(void *context, size_t hdrlen, unsigned char tag,
	      const void *value, size_t vlen)
{
	struct rsa_key *key = context;

	key->e = mpi_read_raw_data(value, vlen);

	if (!key->e)
		return -ENOMEM;

	return 0;
}

int rsa_get_d(void *context, size_t hdrlen, unsigned char tag,
	      const void *value, size_t vlen)
{
	struct rsa_key *key = context;

	key->d = mpi_read_raw_data(value, vlen);

	if (!key->d)
		return -ENOMEM;

	/* In FIPS mode only allow key size 2K & 3K */
	if (fips_enabled && (mpi_get_size(key->d) != 256 &&
			     mpi_get_size(key->d) != 384)) {
		pr_err("RSA: key size not allowed in FIPS mode\n");
		mpi_free(key->d);
		key->d = NULL;
		return -EINVAL;
	}
	return 0;
}

static void free_mpis(struct rsa_key *key)
{
	mpi_free(key->n);
	mpi_free(key->e);
	mpi_free(key->d);
	key->n = NULL;
	key->e = NULL;
	key->d = NULL;
}

/**
 * rsa_free_key() - frees rsa key allocated by rsa_parse_key()
 *
 * @rsa_key:	struct rsa_key key representation
 */
void rsa_free_key(struct rsa_key *key)
{
	free_mpis(key);
}
EXPORT_SYMBOL_GPL(rsa_free_key);

/**
 * rsa_parse_pub_key() - extracts an rsa public key from BER encoded buffer
 *			 and stores it in the provided struct rsa_key
 *
 * @rsa_key:	struct rsa_key key representation
 * @key:	key in BER format
 * @key_len:	length of key
 *
 * Return:	0 on success or error code in case of error
 */
int rsa_parse_pub_key(struct rsa_key *rsa_key, const void *key,
		      unsigned int key_len)
{
	int ret;

	free_mpis(rsa_key);
	ret = asn1_ber_decoder(&rsapubkey_decoder, rsa_key, key, key_len);
	if (ret < 0)
		goto error;

	return 0;
error:
	free_mpis(rsa_key);
	return ret;
}
EXPORT_SYMBOL_GPL(rsa_parse_pub_key);

/**
 * rsa_parse_pub_key() - extracts an rsa private key from BER encoded buffer
 *			 and stores it in the provided struct rsa_key
 *
 * @rsa_key:	struct rsa_key key representation
 * @key:	key in BER format
 * @key_len:	length of key
 *
 * Return:	0 on success or error code in case of error
 */
int rsa_parse_priv_key(struct rsa_key *rsa_key, const void *key,
		       unsigned int key_len)
{
	int ret;

	free_mpis(rsa_key);
	ret = asn1_ber_decoder(&rsaprivkey_decoder, rsa_key, key, key_len);
	if (ret < 0)
		goto error;

	return 0;
error:
	free_mpis(rsa_key);
	return ret;
}
EXPORT_SYMBOL_GPL(rsa_parse_priv_key);