1 /* 2 * Copyright (c) 2018 Thomas Pornin <pornin@bolet.org> 3 * 4 * Permission is hereby granted, free of charge, to any person obtaining 5 * a copy of this software and associated documentation files (the 6 * "Software"), to deal in the Software without restriction, including 7 * without limitation the rights to use, copy, modify, merge, publish, 8 * distribute, sublicense, and/or sell copies of the Software, and to 9 * permit persons to whom the Software is furnished to do so, subject to 10 * the following conditions: 11 * 12 * The above copyright notice and this permission notice shall be 13 * included in all copies or substantial portions of the Software. 14 * 15 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, 16 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF 17 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND 18 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS 19 * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN 20 * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN 21 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE 22 * SOFTWARE. 23 */ 24 25 #include "inner.h" 26 27 /* see inner.h */ 28 const unsigned char * 29 br_get_curve_OID(int curve) 30 { 31 static const unsigned char OID_secp256r1[] = { 32 0x08, 0x2a, 0x86, 0x48, 0xce, 0x3d, 0x03, 0x01, 0x07 33 }; 34 static const unsigned char OID_secp384r1[] = { 35 0x05, 0x2b, 0x81, 0x04, 0x00, 0x22 36 }; 37 static const unsigned char OID_secp521r1[] = { 38 0x05, 0x2b, 0x81, 0x04, 0x00, 0x23 39 }; 40 41 switch (curve) { 42 case BR_EC_secp256r1: return OID_secp256r1; 43 case BR_EC_secp384r1: return OID_secp384r1; 44 case BR_EC_secp521r1: return OID_secp521r1; 45 default: 46 return NULL; 47 } 48 } 49 50 /* see inner.h */ 51 size_t 52 br_encode_ec_raw_der_inner(void *dest, 53 const br_ec_private_key *sk, const br_ec_public_key *pk, 54 int include_curve_oid) 55 { 56 /* 57 * ASN.1 format: 58 * 59 * ECPrivateKey ::= SEQUENCE { 60 * version INTEGER { ecPrivkeyVer1(1) } (ecPrivkeyVer1), 61 * privateKey OCTET STRING, 62 * parameters [0] ECParameters {{ NamedCurve }} OPTIONAL, 63 * publicKey [1] BIT STRING OPTIONAL 64 * } 65 * 66 * The tages '[0]' and '[1]' are explicit. The 'ECParameters' 67 * is a CHOICE; in our case, it will always be an OBJECT IDENTIFIER 68 * that identifies the curve. 69 * 70 * The value of the 'privateKey' field is the raw unsigned big-endian 71 * encoding of the private key (integer modulo the curve subgroup 72 * order); there is no INTEGER tag, and the leading bit may be 1. 73 * Also, leading bytes of value 0x00 are _not_ removed. 74 * 75 * The 'publicKey' contents are the raw encoded public key point, 76 * normally uncompressed (leading byte of value 0x04, followed 77 * by the unsigned big-endian encodings of the X and Y coordinates, 78 * padded to the full field length if necessary). 79 */ 80 81 size_t len_version, len_privateKey, len_parameters, len_publicKey; 82 size_t len_publicKey_bits, len_seq; 83 const unsigned char *oid; 84 85 if (include_curve_oid) { 86 oid = br_get_curve_OID(sk->curve); 87 if (oid == NULL) { 88 return 0; 89 } 90 } else { 91 oid = NULL; 92 } 93 len_version = 3; 94 len_privateKey = 1 + len_of_len(sk->xlen) + sk->xlen; 95 if (include_curve_oid) { 96 len_parameters = 4 + oid[0]; 97 } else { 98 len_parameters = 0; 99 } 100 if (pk == NULL) { 101 len_publicKey = 0; 102 len_publicKey_bits = 0; 103 } else { 104 len_publicKey_bits = 2 + len_of_len(pk->qlen) + pk->qlen; 105 len_publicKey = 1 + len_of_len(len_publicKey_bits) 106 + len_publicKey_bits; 107 } 108 len_seq = len_version + len_privateKey + len_parameters + len_publicKey; 109 if (dest == NULL) { 110 return 1 + len_of_len(len_seq) + len_seq; 111 } else { 112 unsigned char *buf; 113 size_t lenlen; 114 115 buf = dest; 116 *buf ++ = 0x30; /* SEQUENCE tag */ 117 lenlen = br_asn1_encode_length(buf, len_seq); 118 buf += lenlen; 119 120 /* version */ 121 *buf ++ = 0x02; 122 *buf ++ = 0x01; 123 *buf ++ = 0x01; 124 125 /* privateKey */ 126 *buf ++ = 0x04; 127 buf += br_asn1_encode_length(buf, sk->xlen); 128 memcpy(buf, sk->x, sk->xlen); 129 buf += sk->xlen; 130 131 /* parameters */ 132 if (include_curve_oid) { 133 *buf ++ = 0xA0; 134 *buf ++ = oid[0] + 2; 135 *buf ++ = 0x06; 136 memcpy(buf, oid, oid[0] + 1); 137 buf += oid[0] + 1; 138 } 139 140 /* publicKey */ 141 if (pk != NULL) { 142 *buf ++ = 0xA1; 143 buf += br_asn1_encode_length(buf, len_publicKey_bits); 144 *buf ++ = 0x03; 145 buf += br_asn1_encode_length(buf, pk->qlen + 1); 146 *buf ++ = 0x00; 147 memcpy(buf, pk->q, pk->qlen); 148 /* buf += pk->qlen; */ 149 } 150 151 return 1 + lenlen + len_seq; 152 } 153 } 154 155 /* see bearssl_x509.h */ 156 size_t 157 br_encode_ec_raw_der(void *dest, 158 const br_ec_private_key *sk, const br_ec_public_key *pk) 159 { 160 return br_encode_ec_raw_der_inner(dest, sk, pk, 1); 161 } 162