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 return ECDSA_sign_ex(type, digest, digest_len, sig, sig_len, NULL, NULL, 77 eckey); 78} 79 80int ECDSA_sign_ex(int type, const uint8_t *digest, size_t digest_len, 81 uint8_t *sig, unsigned int *sig_len, const BIGNUM *kinv, 82 const BIGNUM *r, const EC_KEY *eckey) { 83 int ret = 0; 84 ECDSA_SIG *s = NULL; 85 86 if (eckey->ecdsa_meth && eckey->ecdsa_meth->sign) { 87 OPENSSL_PUT_ERROR(ECDSA, ECDSA_R_NOT_IMPLEMENTED); 88 *sig_len = 0; 89 goto err; 90 } 91 92 s = ECDSA_do_sign_ex(digest, digest_len, kinv, r, eckey); 93 if (s == NULL) { 94 *sig_len = 0; 95 goto err; 96 } 97 98 CBB cbb; 99 CBB_zero(&cbb); 100 size_t len; 101 if (!CBB_init_fixed(&cbb, sig, ECDSA_size(eckey)) || 102 !ECDSA_SIG_marshal(&cbb, s) || 103 !CBB_finish(&cbb, NULL, &len)) { 104 OPENSSL_PUT_ERROR(ECDSA, ECDSA_R_ENCODE_ERROR); 105 CBB_cleanup(&cbb); 106 *sig_len = 0; 107 goto err; 108 } 109 *sig_len = (unsigned)len; 110 ret = 1; 111 112err: 113 ECDSA_SIG_free(s); 114 return ret; 115} 116 117int ECDSA_verify(int type, const uint8_t *digest, size_t digest_len, 118 const uint8_t *sig, size_t sig_len, const EC_KEY *eckey) { 119 ECDSA_SIG *s; 120 int ret = 0; 121 uint8_t *der = NULL; 122 123 /* Decode the ECDSA signature. */ 124 s = ECDSA_SIG_from_bytes(sig, sig_len); 125 if (s == NULL) { 126 goto err; 127 } 128 129 /* Defend against potential laxness in the DER parser. */ 130 size_t der_len; 131 if (!ECDSA_SIG_to_bytes(&der, &der_len, s) || 132 der_len != sig_len || OPENSSL_memcmp(sig, der, sig_len) != 0) { 133 /* This should never happen. crypto/bytestring is strictly DER. */ 134 OPENSSL_PUT_ERROR(ECDSA, ERR_R_INTERNAL_ERROR); 135 goto err; 136 } 137 138 ret = ECDSA_do_verify(digest, digest_len, s, eckey); 139 140err: 141 OPENSSL_free(der); 142 ECDSA_SIG_free(s); 143 return ret; 144} 145 146 147size_t ECDSA_size(const EC_KEY *key) { 148 if (key == NULL) { 149 return 0; 150 } 151 152 size_t group_order_size; 153 if (key->ecdsa_meth && key->ecdsa_meth->group_order_size) { 154 group_order_size = key->ecdsa_meth->group_order_size(key); 155 } else { 156 const EC_GROUP *group = EC_KEY_get0_group(key); 157 if (group == NULL) { 158 return 0; 159 } 160 161 group_order_size = BN_num_bytes(EC_GROUP_get0_order(group)); 162 } 163 164 return ECDSA_SIG_max_len(group_order_size); 165} 166 167ECDSA_SIG *ECDSA_SIG_parse(CBS *cbs) { 168 ECDSA_SIG *ret = ECDSA_SIG_new(); 169 if (ret == NULL) { 170 return NULL; 171 } 172 CBS child; 173 if (!CBS_get_asn1(cbs, &child, CBS_ASN1_SEQUENCE) || 174 !BN_parse_asn1_unsigned(&child, ret->r) || 175 !BN_parse_asn1_unsigned(&child, ret->s) || 176 CBS_len(&child) != 0) { 177 OPENSSL_PUT_ERROR(ECDSA, ECDSA_R_BAD_SIGNATURE); 178 ECDSA_SIG_free(ret); 179 return NULL; 180 } 181 return ret; 182} 183 184ECDSA_SIG *ECDSA_SIG_from_bytes(const uint8_t *in, size_t in_len) { 185 CBS cbs; 186 CBS_init(&cbs, in, in_len); 187 ECDSA_SIG *ret = ECDSA_SIG_parse(&cbs); 188 if (ret == NULL || CBS_len(&cbs) != 0) { 189 OPENSSL_PUT_ERROR(ECDSA, ECDSA_R_BAD_SIGNATURE); 190 ECDSA_SIG_free(ret); 191 return NULL; 192 } 193 return ret; 194} 195 196int ECDSA_SIG_marshal(CBB *cbb, const ECDSA_SIG *sig) { 197 CBB child; 198 if (!CBB_add_asn1(cbb, &child, CBS_ASN1_SEQUENCE) || 199 !BN_marshal_asn1(&child, sig->r) || 200 !BN_marshal_asn1(&child, sig->s) || 201 !CBB_flush(cbb)) { 202 OPENSSL_PUT_ERROR(ECDSA, ECDSA_R_ENCODE_ERROR); 203 return 0; 204 } 205 return 1; 206} 207 208int ECDSA_SIG_to_bytes(uint8_t **out_bytes, size_t *out_len, 209 const ECDSA_SIG *sig) { 210 CBB cbb; 211 CBB_zero(&cbb); 212 if (!CBB_init(&cbb, 0) || 213 !ECDSA_SIG_marshal(&cbb, sig) || 214 !CBB_finish(&cbb, out_bytes, out_len)) { 215 OPENSSL_PUT_ERROR(ECDSA, ECDSA_R_ENCODE_ERROR); 216 CBB_cleanup(&cbb); 217 return 0; 218 } 219 return 1; 220} 221 222/* der_len_len returns the number of bytes needed to represent a length of |len| 223 * in DER. */ 224static size_t der_len_len(size_t len) { 225 if (len < 0x80) { 226 return 1; 227 } 228 size_t ret = 1; 229 while (len > 0) { 230 ret++; 231 len >>= 8; 232 } 233 return ret; 234} 235 236size_t ECDSA_SIG_max_len(size_t order_len) { 237 /* Compute the maximum length of an |order_len| byte integer. Defensively 238 * assume that the leading 0x00 is included. */ 239 size_t integer_len = 1 /* tag */ + der_len_len(order_len + 1) + 1 + order_len; 240 if (integer_len < order_len) { 241 return 0; 242 } 243 /* An ECDSA signature is two INTEGERs. */ 244 size_t value_len = 2 * integer_len; 245 if (value_len < integer_len) { 246 return 0; 247 } 248 /* Add the header. */ 249 size_t ret = 1 /* tag */ + der_len_len(value_len) + value_len; 250 if (ret < value_len) { 251 return 0; 252 } 253 return ret; 254} 255 256ECDSA_SIG *d2i_ECDSA_SIG(ECDSA_SIG **out, const uint8_t **inp, long len) { 257 if (len < 0) { 258 return NULL; 259 } 260 CBS cbs; 261 CBS_init(&cbs, *inp, (size_t)len); 262 ECDSA_SIG *ret = ECDSA_SIG_parse(&cbs); 263 if (ret == NULL) { 264 return NULL; 265 } 266 if (out != NULL) { 267 ECDSA_SIG_free(*out); 268 *out = ret; 269 } 270 *inp = CBS_data(&cbs); 271 return ret; 272} 273 274int i2d_ECDSA_SIG(const ECDSA_SIG *sig, uint8_t **outp) { 275 CBB cbb; 276 if (!CBB_init(&cbb, 0) || 277 !ECDSA_SIG_marshal(&cbb, sig)) { 278 CBB_cleanup(&cbb); 279 return -1; 280 } 281 return CBB_finish_i2d(&cbb, outp); 282} 283