1/* ====================================================================
2 * Copyright (c) 1998-2005 The OpenSSL Project. All rights reserved.
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
6 * are met:
7 *
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 *
11 * 2. Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in
13 * the documentation and/or other materials provided with the
14 * distribution.
15 *
16 * 3. All advertising materials mentioning features or use of this
17 * software must display the following acknowledgment:
18 * "This product includes software developed by the OpenSSL Project
19 * for use in the OpenSSL Toolkit. (http://www.OpenSSL.org/)"
20 *
21 * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
22 * endorse or promote products derived from this software without
23 * prior written permission. For written permission, please contact
24 * openssl-core@OpenSSL.org.
25 *
26 * 5. Products derived from this software may not be called "OpenSSL"
27 * nor may "OpenSSL" appear in their names without prior written
28 * permission of the OpenSSL Project.
29 *
30 * 6. Redistributions of any form whatsoever must retain the following
31 * acknowledgment:
32 * "This product includes software developed by the OpenSSL Project
33 * for use in the OpenSSL Toolkit (http://www.OpenSSL.org/)"
34 *
35 * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
36 * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
37 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
38 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR
39 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
40 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
41 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
42 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
43 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
44 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
45 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
46 * OF THE POSSIBILITY OF SUCH DAMAGE.
47 * ====================================================================
48 *
49 * This product includes cryptographic software written by Eric Young
50 * (eay@cryptsoft.com). This product includes software written by Tim
51 * Hudson (tjh@cryptsoft.com). */
52
53#include <openssl/ecdsa.h>
54
55#include <limits.h>
56#include <string.h>
57
58#include <openssl/bn.h>
59#include <openssl/bytestring.h>
60#include <openssl/err.h>
61#include <openssl/ec_key.h>
62#include <openssl/mem.h>
63
64#include "../bytestring/internal.h"
65#include "../fipsmodule/ec/internal.h"
66#include "../internal.h"
67
68
69int ECDSA_sign(int type, const uint8_t *digest, size_t digest_len, uint8_t *sig,
70 unsigned int *sig_len, const EC_KEY *eckey) {
71 if (eckey->ecdsa_meth && eckey->ecdsa_meth->sign) {
72 return eckey->ecdsa_meth->sign(digest, digest_len, sig, sig_len,
73 (EC_KEY*) eckey /* cast away const */);
74 }
75
76 int ret = 0;
77 ECDSA_SIG *s = ECDSA_do_sign(digest, digest_len, eckey);
78 if (s == NULL) {
79 *sig_len = 0;
80 goto err;
81 }
82
83 CBB cbb;
84 CBB_zero(&cbb);
85 size_t len;
86 if (!CBB_init_fixed(&cbb, sig, ECDSA_size(eckey)) ||
87 !ECDSA_SIG_marshal(&cbb, s) ||
88 !CBB_finish(&cbb, NULL, &len)) {
89 OPENSSL_PUT_ERROR(ECDSA, ECDSA_R_ENCODE_ERROR);
90 CBB_cleanup(&cbb);
91 *sig_len = 0;
92 goto err;
93 }
94 *sig_len = (unsigned)len;
95 ret = 1;
96
97err:
98 ECDSA_SIG_free(s);
99 return ret;
100}
101
102int ECDSA_verify(int type, const uint8_t *digest, size_t digest_len,
103 const uint8_t *sig, size_t sig_len, const EC_KEY *eckey) {
104 ECDSA_SIG *s;
105 int ret = 0;
106 uint8_t *der = NULL;
107
108 // Decode the ECDSA signature.
109 s = ECDSA_SIG_from_bytes(sig, sig_len);
110 if (s == NULL) {
111 goto err;
112 }
113
114 // Defend against potential laxness in the DER parser.
115 size_t der_len;
116 if (!ECDSA_SIG_to_bytes(&der, &der_len, s) ||
117 der_len != sig_len || OPENSSL_memcmp(sig, der, sig_len) != 0) {
118 // This should never happen. crypto/bytestring is strictly DER.
119 OPENSSL_PUT_ERROR(ECDSA, ERR_R_INTERNAL_ERROR);
120 goto err;
121 }
122
123 ret = ECDSA_do_verify(digest, digest_len, s, eckey);
124
125err:
126 OPENSSL_free(der);
127 ECDSA_SIG_free(s);
128 return ret;
129}
130
131
132size_t ECDSA_size(const EC_KEY *key) {
133 if (key == NULL) {
134 return 0;
135 }
136
137 size_t group_order_size;
138 if (key->ecdsa_meth && key->ecdsa_meth->group_order_size) {
139 group_order_size = key->ecdsa_meth->group_order_size(key);
140 } else {
141 const EC_GROUP *group = EC_KEY_get0_group(key);
142 if (group == NULL) {
143 return 0;
144 }
145
146 group_order_size = BN_num_bytes(EC_GROUP_get0_order(group));
147 }
148
149 return ECDSA_SIG_max_len(group_order_size);
150}
151
152ECDSA_SIG *ECDSA_SIG_parse(CBS *cbs) {
153 ECDSA_SIG *ret = ECDSA_SIG_new();
154 if (ret == NULL) {
155 return NULL;
156 }
157 CBS child;
158 if (!CBS_get_asn1(cbs, &child, CBS_ASN1_SEQUENCE) ||
159 !BN_parse_asn1_unsigned(&child, ret->r) ||
160 !BN_parse_asn1_unsigned(&child, ret->s) ||
161 CBS_len(&child) != 0) {
162 OPENSSL_PUT_ERROR(ECDSA, ECDSA_R_BAD_SIGNATURE);
163 ECDSA_SIG_free(ret);
164 return NULL;
165 }
166 return ret;
167}
168
169ECDSA_SIG *ECDSA_SIG_from_bytes(const uint8_t *in, size_t in_len) {
170 CBS cbs;
171 CBS_init(&cbs, in, in_len);
172 ECDSA_SIG *ret = ECDSA_SIG_parse(&cbs);
173 if (ret == NULL || CBS_len(&cbs) != 0) {
174 OPENSSL_PUT_ERROR(ECDSA, ECDSA_R_BAD_SIGNATURE);
175 ECDSA_SIG_free(ret);
176 return NULL;
177 }
178 return ret;
179}
180
181int ECDSA_SIG_marshal(CBB *cbb, const ECDSA_SIG *sig) {
182 CBB child;
183 if (!CBB_add_asn1(cbb, &child, CBS_ASN1_SEQUENCE) ||
184 !BN_marshal_asn1(&child, sig->r) ||
185 !BN_marshal_asn1(&child, sig->s) ||
186 !CBB_flush(cbb)) {
187 OPENSSL_PUT_ERROR(ECDSA, ECDSA_R_ENCODE_ERROR);
188 return 0;
189 }
190 return 1;
191}
192
193int ECDSA_SIG_to_bytes(uint8_t **out_bytes, size_t *out_len,
194 const ECDSA_SIG *sig) {
195 CBB cbb;
196 CBB_zero(&cbb);
197 if (!CBB_init(&cbb, 0) ||
198 !ECDSA_SIG_marshal(&cbb, sig) ||
199 !CBB_finish(&cbb, out_bytes, out_len)) {
200 OPENSSL_PUT_ERROR(ECDSA, ECDSA_R_ENCODE_ERROR);
201 CBB_cleanup(&cbb);
202 return 0;
203 }
204 return 1;
205}
206
207// der_len_len returns the number of bytes needed to represent a length of |len|
208// in DER.
209static size_t der_len_len(size_t len) {
210 if (len < 0x80) {
211 return 1;
212 }
213 size_t ret = 1;
214 while (len > 0) {
215 ret++;
216 len >>= 8;
217 }
218 return ret;
219}
220
221size_t ECDSA_SIG_max_len(size_t order_len) {
222 // Compute the maximum length of an |order_len| byte integer. Defensively
223 // assume that the leading 0x00 is included.
224 size_t integer_len = 1 /* tag */ + der_len_len(order_len + 1) + 1 + order_len;
225 if (integer_len < order_len) {
226 return 0;
227 }
228 // An ECDSA signature is two INTEGERs.
229 size_t value_len = 2 * integer_len;
230 if (value_len < integer_len) {
231 return 0;
232 }
233 // Add the header.
234 size_t ret = 1 /* tag */ + der_len_len(value_len) + value_len;
235 if (ret < value_len) {
236 return 0;
237 }
238 return ret;
239}
240
241ECDSA_SIG *d2i_ECDSA_SIG(ECDSA_SIG **out, const uint8_t **inp, long len) {
242 if (len < 0) {
243 return NULL;
244 }
245 CBS cbs;
246 CBS_init(&cbs, *inp, (size_t)len);
247 ECDSA_SIG *ret = ECDSA_SIG_parse(&cbs);
248 if (ret == NULL) {
249 return NULL;
250 }
251 if (out != NULL) {
252 ECDSA_SIG_free(*out);
253 *out = ret;
254 }
255 *inp = CBS_data(&cbs);
256 return ret;
257}
258
259int i2d_ECDSA_SIG(const ECDSA_SIG *sig, uint8_t **outp) {
260 CBB cbb;
261 if (!CBB_init(&cbb, 0) ||
262 !ECDSA_SIG_marshal(&cbb, sig)) {
263 CBB_cleanup(&cbb);
264 return -1;
265 }
266 return CBB_finish_i2d(&cbb, outp);
267}
268