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 "../ec/internal.h"
65
66
ECDSA_size(const EC_KEY * key)67 size_t ECDSA_size(const EC_KEY *key) {
68 if (key == NULL) {
69 return 0;
70 }
71
72 size_t group_order_size;
73 if (key->ecdsa_meth && key->ecdsa_meth->group_order_size) {
74 group_order_size = key->ecdsa_meth->group_order_size(key);
75 } else {
76 const EC_GROUP *group = EC_KEY_get0_group(key);
77 if (group == NULL) {
78 return 0;
79 }
80
81 group_order_size = BN_num_bytes(EC_GROUP_get0_order(group));
82 }
83
84 return ECDSA_SIG_max_len(group_order_size);
85 }
86
ECDSA_SIG_new(void)87 ECDSA_SIG *ECDSA_SIG_new(void) {
88 ECDSA_SIG *sig = OPENSSL_malloc(sizeof(ECDSA_SIG));
89 if (sig == NULL) {
90 return NULL;
91 }
92 sig->r = BN_new();
93 sig->s = BN_new();
94 if (sig->r == NULL || sig->s == NULL) {
95 ECDSA_SIG_free(sig);
96 return NULL;
97 }
98 return sig;
99 }
100
ECDSA_SIG_free(ECDSA_SIG * sig)101 void ECDSA_SIG_free(ECDSA_SIG *sig) {
102 if (sig == NULL) {
103 return;
104 }
105
106 BN_free(sig->r);
107 BN_free(sig->s);
108 OPENSSL_free(sig);
109 }
110
ECDSA_SIG_parse(CBS * cbs)111 ECDSA_SIG *ECDSA_SIG_parse(CBS *cbs) {
112 ECDSA_SIG *ret = ECDSA_SIG_new();
113 if (ret == NULL) {
114 return NULL;
115 }
116 CBS child;
117 if (!CBS_get_asn1(cbs, &child, CBS_ASN1_SEQUENCE) ||
118 !BN_cbs2unsigned(&child, ret->r) ||
119 !BN_cbs2unsigned(&child, ret->s) ||
120 CBS_len(&child) != 0) {
121 OPENSSL_PUT_ERROR(ECDSA, ECDSA_R_BAD_SIGNATURE);
122 ECDSA_SIG_free(ret);
123 return NULL;
124 }
125 return ret;
126 }
127
ECDSA_SIG_from_bytes(const uint8_t * in,size_t in_len)128 ECDSA_SIG *ECDSA_SIG_from_bytes(const uint8_t *in, size_t in_len) {
129 CBS cbs;
130 CBS_init(&cbs, in, in_len);
131 ECDSA_SIG *ret = ECDSA_SIG_parse(&cbs);
132 if (ret == NULL || CBS_len(&cbs) != 0) {
133 OPENSSL_PUT_ERROR(ECDSA, ECDSA_R_BAD_SIGNATURE);
134 ECDSA_SIG_free(ret);
135 return NULL;
136 }
137 return ret;
138 }
139
ECDSA_SIG_marshal(CBB * cbb,const ECDSA_SIG * sig)140 int ECDSA_SIG_marshal(CBB *cbb, const ECDSA_SIG *sig) {
141 CBB child;
142 if (!CBB_add_asn1(cbb, &child, CBS_ASN1_SEQUENCE) ||
143 !BN_bn2cbb(&child, sig->r) ||
144 !BN_bn2cbb(&child, sig->s) ||
145 !CBB_flush(cbb)) {
146 OPENSSL_PUT_ERROR(ECDSA, ECDSA_R_ENCODE_ERROR);
147 return 0;
148 }
149 return 1;
150 }
151
ECDSA_SIG_to_bytes(uint8_t ** out_bytes,size_t * out_len,const ECDSA_SIG * sig)152 int ECDSA_SIG_to_bytes(uint8_t **out_bytes, size_t *out_len,
153 const ECDSA_SIG *sig) {
154 CBB cbb;
155 CBB_zero(&cbb);
156 if (!CBB_init(&cbb, 0) ||
157 !ECDSA_SIG_marshal(&cbb, sig) ||
158 !CBB_finish(&cbb, out_bytes, out_len)) {
159 OPENSSL_PUT_ERROR(ECDSA, ECDSA_R_ENCODE_ERROR);
160 CBB_cleanup(&cbb);
161 return 0;
162 }
163 return 1;
164 }
165
166 /* der_len_len returns the number of bytes needed to represent a length of |len|
167 * in DER. */
der_len_len(size_t len)168 static size_t der_len_len(size_t len) {
169 if (len < 0x80) {
170 return 1;
171 }
172 size_t ret = 1;
173 while (len > 0) {
174 ret++;
175 len >>= 8;
176 }
177 return ret;
178 }
179
ECDSA_SIG_max_len(size_t order_len)180 size_t ECDSA_SIG_max_len(size_t order_len) {
181 /* Compute the maximum length of an |order_len| byte integer. Defensively
182 * assume that the leading 0x00 is included. */
183 size_t integer_len = 1 /* tag */ + der_len_len(order_len + 1) + 1 + order_len;
184 if (integer_len < order_len) {
185 return 0;
186 }
187 /* An ECDSA signature is two INTEGERs. */
188 size_t value_len = 2 * integer_len;
189 if (value_len < integer_len) {
190 return 0;
191 }
192 /* Add the header. */
193 size_t ret = 1 /* tag */ + der_len_len(value_len) + value_len;
194 if (ret < value_len) {
195 return 0;
196 }
197 return ret;
198 }
199
d2i_ECDSA_SIG(ECDSA_SIG ** out,const uint8_t ** inp,long len)200 ECDSA_SIG *d2i_ECDSA_SIG(ECDSA_SIG **out, const uint8_t **inp, long len) {
201 if (len < 0) {
202 return NULL;
203 }
204 CBS cbs;
205 CBS_init(&cbs, *inp, (size_t)len);
206 ECDSA_SIG *ret = ECDSA_SIG_parse(&cbs);
207 if (ret == NULL) {
208 return NULL;
209 }
210 if (out != NULL) {
211 ECDSA_SIG_free(*out);
212 *out = ret;
213 }
214 *inp += (size_t)len - CBS_len(&cbs);
215 return ret;
216 }
217
i2d_ECDSA_SIG(const ECDSA_SIG * sig,uint8_t ** outp)218 int i2d_ECDSA_SIG(const ECDSA_SIG *sig, uint8_t **outp) {
219 uint8_t *der;
220 size_t der_len;
221 if (!ECDSA_SIG_to_bytes(&der, &der_len, sig)) {
222 return -1;
223 }
224 if (der_len > INT_MAX) {
225 OPENSSL_PUT_ERROR(ECDSA, ERR_R_OVERFLOW);
226 OPENSSL_free(der);
227 return -1;
228 }
229 if (outp != NULL) {
230 if (*outp == NULL) {
231 *outp = der;
232 der = NULL;
233 } else {
234 memcpy(*outp, der, der_len);
235 *outp += der_len;
236 }
237 }
238 OPENSSL_free(der);
239 return (int)der_len;
240 }
241