Coverage Report

Created: 2020-09-01 07:05

/libfido2/src/rs256.c
Line
Count
Source (jump to first uncovered line)
1
/*
2
 * Copyright (c) 2018 Yubico AB. All rights reserved.
3
 * Use of this source code is governed by a BSD-style
4
 * license that can be found in the LICENSE file.
5
 */
6
7
#include <openssl/bn.h>
8
#include <openssl/rsa.h>
9
#include <openssl/evp.h>
10
#include <openssl/obj_mac.h>
11
12
#include <string.h>
13
#include "fido.h"
14
#include "fido/rs256.h"
15
16
#if OPENSSL_VERSION_NUMBER < 0x10100000L
17
static int
18
RSA_bits(const RSA *r)
19
{
20
        return (BN_num_bits(r->n));
21
}
22
23
static int
24
RSA_set0_key(RSA *r, BIGNUM *n, BIGNUM *e, BIGNUM *d)
25
{
26
        r->n = n;
27
        r->e = e;
28
        r->d = d;
29
30
        return (1);
31
}
32
33
static void
34
RSA_get0_key(const RSA *r, const BIGNUM **n, const BIGNUM **e, const BIGNUM **d)
35
{
36
        *n = r->n;
37
        *e = r->e;
38
        *d = r->d;
39
}
40
#endif /* OPENSSL_VERSION_NUMBER < 0x10100000L */
41
42
static int
43
decode_bignum(const cbor_item_t *item, void *ptr, size_t len)
44
120
{
45
120
        if (cbor_isa_bytestring(item) == false ||
46
120
            cbor_bytestring_is_definite(item) == false ||
47
120
            cbor_bytestring_length(item) != len) {
48
0
                fido_log_debug("%s: cbor type", __func__);
49
0
                return (-1);
50
0
        }
51
120
52
120
        memcpy(ptr, cbor_bytestring_handle(item), len);
53
120
54
120
        return (0);
55
120
}
56
57
static int
58
decode_rsa_pubkey(const cbor_item_t *key, const cbor_item_t *val, void *arg)
59
242
{
60
242
        rs256_pk_t *k = arg;
61
242
62
242
        if (cbor_isa_negint(key) == false ||
63
242
            cbor_int_get_width(key) != CBOR_INT_8)
64
122
                return (0); /* ignore */
65
120
66
120
        switch (cbor_get_uint8(key)) {
67
60
        case 0: /* modulus */
68
60
                return (decode_bignum(val, &k->n, sizeof(k->n)));
69
60
        case 1: /* public exponent */
70
60
                return (decode_bignum(val, &k->e, sizeof(k->e)));
71
0
        }
72
0
73
0
        return (0); /* ignore */
74
0
}
75
76
int
77
rs256_pk_decode(const cbor_item_t *item, rs256_pk_t *k)
78
65
{
79
65
        if (cbor_isa_map(item) == false ||
80
65
            cbor_map_is_definite(item) == false ||
81
65
            cbor_map_iter(item, k, decode_rsa_pubkey) < 0) {
82
4
                fido_log_debug("%s: cbor type", __func__);
83
4
                return (-1);
84
4
        }
85
61
86
61
        return (0);
87
61
}
88
89
rs256_pk_t *
90
rs256_pk_new(void)
91
820
{
92
820
        return (calloc(1, sizeof(rs256_pk_t)));
93
820
}
94
95
void
96
rs256_pk_free(rs256_pk_t **pkp)
97
1.86k
{
98
1.86k
        rs256_pk_t *pk;
99
1.86k
100
1.86k
        if (pkp == NULL || (pk = *pkp) == NULL)
101
1.86k
                return;
102
817
103
817
        explicit_bzero(pk, sizeof(*pk));
104
817
        free(pk);
105
817
106
817
        *pkp = NULL;
107
817
}
108
109
int
110
rs256_pk_from_ptr(rs256_pk_t *pk, const void *ptr, size_t len)
111
423
{
112
423
        if (len < sizeof(*pk))
113
385
                return (FIDO_ERR_INVALID_ARGUMENT);
114
38
115
38
        memcpy(pk, ptr, sizeof(*pk));
116
38
117
38
        return (FIDO_OK);
118
38
}
119
120
EVP_PKEY *
121
rs256_pk_to_EVP_PKEY(const rs256_pk_t *k)
122
516
{
123
516
        RSA             *rsa = NULL;
124
516
        EVP_PKEY        *pkey = NULL;
125
516
        BIGNUM          *n = NULL;
126
516
        BIGNUM          *e = NULL;
127
516
        int              ok = -1;
128
516
129
516
        if ((n = BN_new()) == NULL || (e = BN_new()) == NULL)
130
516
                goto fail;
131
501
132
501
        if (BN_bin2bn(k->n, sizeof(k->n), n) == NULL ||
133
501
            BN_bin2bn(k->e, sizeof(k->e), e) == NULL) {
134
12
                fido_log_debug("%s: BN_bin2bn", __func__);
135
12
                goto fail;
136
12
        }
137
489
138
489
        if ((rsa = RSA_new()) == NULL || RSA_set0_key(rsa, n, e, NULL) == 0) {
139
9
                fido_log_debug("%s: RSA_set0_key", __func__);
140
9
                goto fail;
141
9
        }
142
480
143
480
        /* at this point, n and e belong to rsa */
144
480
        n = NULL;
145
480
        e = NULL;
146
480
147
480
        if ((pkey = EVP_PKEY_new()) == NULL ||
148
480
            EVP_PKEY_assign_RSA(pkey, rsa) == 0) {
149
14
                fido_log_debug("%s: EVP_PKEY_assign_RSA", __func__);
150
14
                goto fail;
151
14
        }
152
466
153
466
        rsa = NULL; /* at this point, rsa belongs to evp */
154
466
155
466
        ok = 0;
156
516
fail:
157
516
        if (n != NULL)
158
516
                BN_free(n);
159
516
        if (e != NULL)
160
516
                BN_free(e);
161
516
        if (rsa != NULL)
162
516
                RSA_free(rsa);
163
516
        if (ok < 0 && pkey != NULL) {
164
6
                EVP_PKEY_free(pkey);
165
6
                pkey = NULL;
166
6
        }
167
516
168
516
        return (pkey);
169
466
}
170
171
int
172
rs256_pk_from_RSA(rs256_pk_t *pk, const RSA *rsa)
173
394
{
174
394
        const BIGNUM    *n = NULL;
175
394
        const BIGNUM    *e = NULL;
176
394
        const BIGNUM    *d = NULL;
177
394
        int              k;
178
394
179
394
        if (RSA_bits(rsa) != 2048) {
180
373
                fido_log_debug("%s: invalid key length", __func__);
181
373
                return (FIDO_ERR_INVALID_ARGUMENT);
182
373
        }
183
21
184
21
        RSA_get0_key(rsa, &n, &e, &d);
185
21
186
21
        if (n == NULL || e == NULL) {
187
0
                fido_log_debug("%s: RSA_get0_key", __func__);
188
0
                return (FIDO_ERR_INTERNAL);
189
0
        }
190
21
191
21
        if ((k = BN_num_bytes(n)) < 0 || (size_t)k > sizeof(pk->n) ||
192
21
            (k = BN_num_bytes(e)) < 0 || (size_t)k > sizeof(pk->e)) {
193
0
                fido_log_debug("%s: invalid key", __func__);
194
0
                return (FIDO_ERR_INTERNAL);
195
0
        }
196
21
197
21
        if ((k = BN_bn2bin(n, pk->n)) < 0 || (size_t)k > sizeof(pk->n) ||
198
21
            (k = BN_bn2bin(e, pk->e)) < 0 || (size_t)k > sizeof(pk->e)) {
199
3
                fido_log_debug("%s: BN_bn2bin", __func__);
200
3
                return (FIDO_ERR_INTERNAL);
201
3
        }
202
18
203
18
        return (FIDO_OK);
204
18
}