Andrew Top | dee8b29 | 2019-01-22 14:48:26 -0800 | [diff] [blame] | 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 | |
| 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 | } |