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 (at) 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 (at) cryptsoft.com). This product includes software written by Tim 51 * Hudson (tjh (at) 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 69 int 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 = NULL; 78 79 if (eckey->ecdsa_meth && eckey->ecdsa_meth->sign) { 80 OPENSSL_PUT_ERROR(ECDSA, ECDSA_R_NOT_IMPLEMENTED); 81 *sig_len = 0; 82 goto err; 83 } 84 85 s = ECDSA_do_sign(digest, digest_len, eckey); 86 if (s == NULL) { 87 *sig_len = 0; 88 goto err; 89 } 90 91 CBB cbb; 92 CBB_zero(&cbb); 93 size_t len; 94 if (!CBB_init_fixed(&cbb, sig, ECDSA_size(eckey)) || 95 !ECDSA_SIG_marshal(&cbb, s) || 96 !CBB_finish(&cbb, NULL, &len)) { 97 OPENSSL_PUT_ERROR(ECDSA, ECDSA_R_ENCODE_ERROR); 98 CBB_cleanup(&cbb); 99 *sig_len = 0; 100 goto err; 101 } 102 *sig_len = (unsigned)len; 103 ret = 1; 104 105 err: 106 ECDSA_SIG_free(s); 107 return ret; 108 } 109 110 int ECDSA_verify(int type, const uint8_t *digest, size_t digest_len, 111 const uint8_t *sig, size_t sig_len, const EC_KEY *eckey) { 112 ECDSA_SIG *s; 113 int ret = 0; 114 uint8_t *der = NULL; 115 116 // Decode the ECDSA signature. 117 s = ECDSA_SIG_from_bytes(sig, sig_len); 118 if (s == NULL) { 119 goto err; 120 } 121 122 // Defend against potential laxness in the DER parser. 123 size_t der_len; 124 if (!ECDSA_SIG_to_bytes(&der, &der_len, s) || 125 der_len != sig_len || OPENSSL_memcmp(sig, der, sig_len) != 0) { 126 // This should never happen. crypto/bytestring is strictly DER. 127 OPENSSL_PUT_ERROR(ECDSA, ERR_R_INTERNAL_ERROR); 128 goto err; 129 } 130 131 ret = ECDSA_do_verify(digest, digest_len, s, eckey); 132 133 err: 134 OPENSSL_free(der); 135 ECDSA_SIG_free(s); 136 return ret; 137 } 138 139 140 size_t ECDSA_size(const EC_KEY *key) { 141 if (key == NULL) { 142 return 0; 143 } 144 145 size_t group_order_size; 146 if (key->ecdsa_meth && key->ecdsa_meth->group_order_size) { 147 group_order_size = key->ecdsa_meth->group_order_size(key); 148 } else { 149 const EC_GROUP *group = EC_KEY_get0_group(key); 150 if (group == NULL) { 151 return 0; 152 } 153 154 group_order_size = BN_num_bytes(EC_GROUP_get0_order(group)); 155 } 156 157 return ECDSA_SIG_max_len(group_order_size); 158 } 159 160 ECDSA_SIG *ECDSA_SIG_parse(CBS *cbs) { 161 ECDSA_SIG *ret = ECDSA_SIG_new(); 162 if (ret == NULL) { 163 return NULL; 164 } 165 CBS child; 166 if (!CBS_get_asn1(cbs, &child, CBS_ASN1_SEQUENCE) || 167 !BN_parse_asn1_unsigned(&child, ret->r) || 168 !BN_parse_asn1_unsigned(&child, ret->s) || 169 CBS_len(&child) != 0) { 170 OPENSSL_PUT_ERROR(ECDSA, ECDSA_R_BAD_SIGNATURE); 171 ECDSA_SIG_free(ret); 172 return NULL; 173 } 174 return ret; 175 } 176 177 ECDSA_SIG *ECDSA_SIG_from_bytes(const uint8_t *in, size_t in_len) { 178 CBS cbs; 179 CBS_init(&cbs, in, in_len); 180 ECDSA_SIG *ret = ECDSA_SIG_parse(&cbs); 181 if (ret == NULL || CBS_len(&cbs) != 0) { 182 OPENSSL_PUT_ERROR(ECDSA, ECDSA_R_BAD_SIGNATURE); 183 ECDSA_SIG_free(ret); 184 return NULL; 185 } 186 return ret; 187 } 188 189 int ECDSA_SIG_marshal(CBB *cbb, const ECDSA_SIG *sig) { 190 CBB child; 191 if (!CBB_add_asn1(cbb, &child, CBS_ASN1_SEQUENCE) || 192 !BN_marshal_asn1(&child, sig->r) || 193 !BN_marshal_asn1(&child, sig->s) || 194 !CBB_flush(cbb)) { 195 OPENSSL_PUT_ERROR(ECDSA, ECDSA_R_ENCODE_ERROR); 196 return 0; 197 } 198 return 1; 199 } 200 201 int ECDSA_SIG_to_bytes(uint8_t **out_bytes, size_t *out_len, 202 const ECDSA_SIG *sig) { 203 CBB cbb; 204 CBB_zero(&cbb); 205 if (!CBB_init(&cbb, 0) || 206 !ECDSA_SIG_marshal(&cbb, sig) || 207 !CBB_finish(&cbb, out_bytes, out_len)) { 208 OPENSSL_PUT_ERROR(ECDSA, ECDSA_R_ENCODE_ERROR); 209 CBB_cleanup(&cbb); 210 return 0; 211 } 212 return 1; 213 } 214 215 // der_len_len returns the number of bytes needed to represent a length of |len| 216 // in DER. 217 static size_t der_len_len(size_t len) { 218 if (len < 0x80) { 219 return 1; 220 } 221 size_t ret = 1; 222 while (len > 0) { 223 ret++; 224 len >>= 8; 225 } 226 return ret; 227 } 228 229 size_t ECDSA_SIG_max_len(size_t order_len) { 230 // Compute the maximum length of an |order_len| byte integer. Defensively 231 // assume that the leading 0x00 is included. 232 size_t integer_len = 1 /* tag */ + der_len_len(order_len + 1) + 1 + order_len; 233 if (integer_len < order_len) { 234 return 0; 235 } 236 // An ECDSA signature is two INTEGERs. 237 size_t value_len = 2 * integer_len; 238 if (value_len < integer_len) { 239 return 0; 240 } 241 // Add the header. 242 size_t ret = 1 /* tag */ + der_len_len(value_len) + value_len; 243 if (ret < value_len) { 244 return 0; 245 } 246 return ret; 247 } 248 249 ECDSA_SIG *d2i_ECDSA_SIG(ECDSA_SIG **out, const uint8_t **inp, long len) { 250 if (len < 0) { 251 return NULL; 252 } 253 CBS cbs; 254 CBS_init(&cbs, *inp, (size_t)len); 255 ECDSA_SIG *ret = ECDSA_SIG_parse(&cbs); 256 if (ret == NULL) { 257 return NULL; 258 } 259 if (out != NULL) { 260 ECDSA_SIG_free(*out); 261 *out = ret; 262 } 263 *inp = CBS_data(&cbs); 264 return ret; 265 } 266 267 int i2d_ECDSA_SIG(const ECDSA_SIG *sig, uint8_t **outp) { 268 CBB cbb; 269 if (!CBB_init(&cbb, 0) || 270 !ECDSA_SIG_marshal(&cbb, sig)) { 271 CBB_cleanup(&cbb); 272 return -1; 273 } 274 return CBB_finish_i2d(&cbb, outp); 275 } 276
