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 "../ec/internal.h" 66 67 68 size_t ECDSA_size(const EC_KEY *key) { 69 if (key == NULL) { 70 return 0; 71 } 72 73 size_t group_order_size; 74 if (key->ecdsa_meth && key->ecdsa_meth->group_order_size) { 75 group_order_size = key->ecdsa_meth->group_order_size(key); 76 } else { 77 const EC_GROUP *group = EC_KEY_get0_group(key); 78 if (group == NULL) { 79 return 0; 80 } 81 82 group_order_size = BN_num_bytes(EC_GROUP_get0_order(group)); 83 } 84 85 return ECDSA_SIG_max_len(group_order_size); 86 } 87 88 ECDSA_SIG *ECDSA_SIG_new(void) { 89 ECDSA_SIG *sig = OPENSSL_malloc(sizeof(ECDSA_SIG)); 90 if (sig == NULL) { 91 return NULL; 92 } 93 sig->r = BN_new(); 94 sig->s = BN_new(); 95 if (sig->r == NULL || sig->s == NULL) { 96 ECDSA_SIG_free(sig); 97 return NULL; 98 } 99 return sig; 100 } 101 102 void ECDSA_SIG_free(ECDSA_SIG *sig) { 103 if (sig == NULL) { 104 return; 105 } 106 107 BN_free(sig->r); 108 BN_free(sig->s); 109 OPENSSL_free(sig); 110 } 111 112 ECDSA_SIG *ECDSA_SIG_parse(CBS *cbs) { 113 ECDSA_SIG *ret = ECDSA_SIG_new(); 114 if (ret == NULL) { 115 return NULL; 116 } 117 CBS child; 118 if (!CBS_get_asn1(cbs, &child, CBS_ASN1_SEQUENCE) || 119 !BN_parse_asn1_unsigned(&child, ret->r) || 120 !BN_parse_asn1_unsigned(&child, ret->s) || 121 CBS_len(&child) != 0) { 122 OPENSSL_PUT_ERROR(ECDSA, ECDSA_R_BAD_SIGNATURE); 123 ECDSA_SIG_free(ret); 124 return NULL; 125 } 126 return ret; 127 } 128 129 ECDSA_SIG *ECDSA_SIG_from_bytes(const uint8_t *in, size_t in_len) { 130 CBS cbs; 131 CBS_init(&cbs, in, in_len); 132 ECDSA_SIG *ret = ECDSA_SIG_parse(&cbs); 133 if (ret == NULL || CBS_len(&cbs) != 0) { 134 OPENSSL_PUT_ERROR(ECDSA, ECDSA_R_BAD_SIGNATURE); 135 ECDSA_SIG_free(ret); 136 return NULL; 137 } 138 return ret; 139 } 140 141 int ECDSA_SIG_marshal(CBB *cbb, const ECDSA_SIG *sig) { 142 CBB child; 143 if (!CBB_add_asn1(cbb, &child, CBS_ASN1_SEQUENCE) || 144 !BN_marshal_asn1(&child, sig->r) || 145 !BN_marshal_asn1(&child, sig->s) || 146 !CBB_flush(cbb)) { 147 OPENSSL_PUT_ERROR(ECDSA, ECDSA_R_ENCODE_ERROR); 148 return 0; 149 } 150 return 1; 151 } 152 153 int ECDSA_SIG_to_bytes(uint8_t **out_bytes, size_t *out_len, 154 const ECDSA_SIG *sig) { 155 CBB cbb; 156 CBB_zero(&cbb); 157 if (!CBB_init(&cbb, 0) || 158 !ECDSA_SIG_marshal(&cbb, sig) || 159 !CBB_finish(&cbb, out_bytes, out_len)) { 160 OPENSSL_PUT_ERROR(ECDSA, ECDSA_R_ENCODE_ERROR); 161 CBB_cleanup(&cbb); 162 return 0; 163 } 164 return 1; 165 } 166 167 /* der_len_len returns the number of bytes needed to represent a length of |len| 168 * in DER. */ 169 static size_t der_len_len(size_t len) { 170 if (len < 0x80) { 171 return 1; 172 } 173 size_t ret = 1; 174 while (len > 0) { 175 ret++; 176 len >>= 8; 177 } 178 return ret; 179 } 180 181 size_t ECDSA_SIG_max_len(size_t order_len) { 182 /* Compute the maximum length of an |order_len| byte integer. Defensively 183 * assume that the leading 0x00 is included. */ 184 size_t integer_len = 1 /* tag */ + der_len_len(order_len + 1) + 1 + order_len; 185 if (integer_len < order_len) { 186 return 0; 187 } 188 /* An ECDSA signature is two INTEGERs. */ 189 size_t value_len = 2 * integer_len; 190 if (value_len < integer_len) { 191 return 0; 192 } 193 /* Add the header. */ 194 size_t ret = 1 /* tag */ + der_len_len(value_len) + value_len; 195 if (ret < value_len) { 196 return 0; 197 } 198 return ret; 199 } 200 201 ECDSA_SIG *d2i_ECDSA_SIG(ECDSA_SIG **out, const uint8_t **inp, long len) { 202 if (len < 0) { 203 return NULL; 204 } 205 CBS cbs; 206 CBS_init(&cbs, *inp, (size_t)len); 207 ECDSA_SIG *ret = ECDSA_SIG_parse(&cbs); 208 if (ret == NULL) { 209 return NULL; 210 } 211 if (out != NULL) { 212 ECDSA_SIG_free(*out); 213 *out = ret; 214 } 215 *inp = CBS_data(&cbs); 216 return ret; 217 } 218 219 int i2d_ECDSA_SIG(const ECDSA_SIG *sig, uint8_t **outp) { 220 CBB cbb; 221 if (!CBB_init(&cbb, 0) || 222 !ECDSA_SIG_marshal(&cbb, sig)) { 223 CBB_cleanup(&cbb); 224 return -1; 225 } 226 return CBB_finish_i2d(&cbb, outp); 227 } 228
