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
|
// SPDX-License-Identifier: GPL-2.0+
/*
* ECDSA signature verification for u-boot
*
* This implements the firmware-side wrapper for ECDSA verification. It bridges
* the struct crypto_algo API to the ECDSA uclass implementations.
*
* Copyright (c) 2020, Alexandru Gagniuc <mr.nuke.me@gmail.com>
*/
#include <crypto/ecdsa-uclass.h>
#include <dm/uclass.h>
#include <u-boot/ecdsa.h>
/*
* Derive size of an ECDSA key from the curve name
*
* While it's possible to extract the key size by using string manipulation,
* use a list of known curves for the time being.
*/
static int ecdsa_key_size(const char *curve_name)
{
if (!strcmp(curve_name, "prime256v1"))
return 256;
else
return 0;
}
static int fdt_get_key(struct ecdsa_public_key *key, const void *fdt, int node)
{
int x_len, y_len;
key->curve_name = fdt_getprop(fdt, node, "ecdsa,curve", NULL);
key->size_bits = ecdsa_key_size(key->curve_name);
if (key->size_bits == 0) {
debug("Unknown ECDSA curve '%s'", key->curve_name);
return -EINVAL;
}
key->x = fdt_getprop(fdt, node, "ecdsa,x-point", &x_len);
key->y = fdt_getprop(fdt, node, "ecdsa,y-point", &y_len);
if (!key->x || !key->y)
return -EINVAL;
if (x_len != (key->size_bits / 8) || y_len != (key->size_bits / 8)) {
printf("%s: node=%d, curve@%p x@%p+%i y@%p+%i\n", __func__,
node, key->curve_name, key->x, x_len, key->y, y_len);
return -EINVAL;
}
return 0;
}
static int ecdsa_verify_hash(struct udevice *dev,
const struct image_sign_info *info,
const void *hash, const void *sig, uint sig_len)
{
const struct ecdsa_ops *ops = device_get_ops(dev);
const struct checksum_algo *algo = info->checksum;
struct ecdsa_public_key key;
int sig_node, key_node, ret;
if (!ops || !ops->verify)
return -ENODEV;
if (info->required_keynode > 0) {
ret = fdt_get_key(&key, info->fdt_blob, info->required_keynode);
if (ret < 0)
return ret;
return ops->verify(dev, &key, hash, algo->checksum_len,
sig, sig_len);
}
sig_node = fdt_subnode_offset(info->fdt_blob, 0, FIT_SIG_NODENAME);
if (sig_node < 0)
return -ENOENT;
/* Try all possible keys under the "/signature" node */
fdt_for_each_subnode(key_node, info->fdt_blob, sig_node) {
ret = fdt_get_key(&key, info->fdt_blob, key_node);
if (ret < 0)
continue;
ret = ops->verify(dev, &key, hash, algo->checksum_len,
sig, sig_len);
/* On success, don't worry about remaining keys */
if (!ret)
return 0;
}
return -EPERM;
}
int ecdsa_verify(struct image_sign_info *info,
const struct image_region region[], int region_count,
uint8_t *sig, uint sig_len)
{
const struct checksum_algo *algo = info->checksum;
uint8_t hash[algo->checksum_len];
struct udevice *dev;
int ret;
ret = uclass_first_device_err(UCLASS_ECDSA, &dev);
if (ret) {
debug("ECDSA: Could not find ECDSA implementation: %d\n", ret);
return ret;
}
ret = algo->calculate(algo->name, region, region_count, hash);
if (ret < 0)
return -EINVAL;
return ecdsa_verify_hash(dev, info, hash, sig, sig_len);
}
U_BOOT_CRYPTO_ALGO(ecdsa) = {
.name = "ecdsa256",
.key_len = ECDSA256_BYTES,
.verify = ecdsa_verify,
};
/*
* uclass definition for ECDSA API
*
* We don't implement any wrappers around ecdsa_ops->verify() because it's
* trivial to call ops->verify().
*/
UCLASS_DRIVER(ecdsa) = {
.id = UCLASS_ECDSA,
.name = "ecdsa_verifier",
};
|
