/*
* Copyright (c) 2018 Thomas Pornin <pornin@bolet.org>
*
* Permission is hereby granted, free of charge, to any person obtaining
* a copy of this software and associated documentation files (the
* "Software"), to deal in the Software without restriction, including
* without limitation the rights to use, copy, modify, merge, publish,
* distribute, sublicense, and/or sell copies of the Software, and to
* permit persons to whom the Software is furnished to do so, subject to
* the following conditions:
*
* The above copyright notice and this permission notice shall be
* included in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
* BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
* ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
* SOFTWARE.
*/
#include "inner.h"
/* see inner.h */
const unsigned char *
br_get_curve_OID(int curve)
{
static const unsigned char OID_secp256r1[] = {
0x08, 0x2a, 0x86, 0x48, 0xce, 0x3d, 0x03, 0x01, 0x07
};
static const unsigned char OID_secp384r1[] = {
0x05, 0x2b, 0x81, 0x04, 0x00, 0x22
};
static const unsigned char OID_secp521r1[] = {
0x05, 0x2b, 0x81, 0x04, 0x00, 0x23
};
switch (curve) {
case BR_EC_secp256r1: return OID_secp256r1;
case BR_EC_secp384r1: return OID_secp384r1;
case BR_EC_secp521r1: return OID_secp521r1;
default:
return NULL;
}
}
/* see inner.h */
size_t
br_encode_ec_raw_der_inner(void *dest,
const br_ec_private_key *sk, const br_ec_public_key *pk,
int include_curve_oid)
{
/*
* ASN.1 format:
*
* ECPrivateKey ::= SEQUENCE {
* version INTEGER { ecPrivkeyVer1(1) } (ecPrivkeyVer1),
* privateKey OCTET STRING,
* parameters [0] ECParameters {{ NamedCurve }} OPTIONAL,
* publicKey [1] BIT STRING OPTIONAL
* }
*
* The tages '[0]' and '[1]' are explicit. The 'ECParameters'
* is a CHOICE; in our case, it will always be an OBJECT IDENTIFIER
* that identifies the curve.
*
* The value of the 'privateKey' field is the raw unsigned big-endian
* encoding of the private key (integer modulo the curve subgroup
* order); there is no INTEGER tag, and the leading bit may be 1.
* Also, leading bytes of value 0x00 are _not_ removed.
*
* The 'publicKey' contents are the raw encoded public key point,
* normally uncompressed (leading byte of value 0x04, followed
* by the unsigned big-endian encodings of the X and Y coordinates,
* padded to the full field length if necessary).
*/
size_t len_version, len_privateKey, len_parameters, len_publicKey;
size_t len_publicKey_bits, len_seq;
const unsigned char *oid;
if (include_curve_oid) {
oid = br_get_curve_OID(sk->curve);
if (oid == NULL) {
return 0;
}
} else {
oid = NULL;
}
len_version = 3;
len_privateKey = 1 + len_of_len(sk->xlen) + sk->xlen;
if (include_curve_oid) {
len_parameters = 4 + oid[0];
} else {
len_parameters = 0;
}
if (pk == NULL) {
len_publicKey = 0;
len_publicKey_bits = 0;
} else {
len_publicKey_bits = 2 + len_of_len(pk->qlen) + pk->qlen;
len_publicKey = 1 + len_of_len(len_publicKey_bits)
+ len_publicKey_bits;
}
len_seq = len_version + len_privateKey + len_parameters + len_publicKey;
if (dest == NULL) {
return 1 + len_of_len(len_seq) + len_seq;
} else {
unsigned char *buf;
size_t lenlen;
buf = dest;
*buf ++ = 0x30; /* SEQUENCE tag */
lenlen = br_asn1_encode_length(buf, len_seq);
buf += lenlen;
/* version */
*buf ++ = 0x02;
*buf ++ = 0x01;
*buf ++ = 0x01;
/* privateKey */
*buf ++ = 0x04;
buf += br_asn1_encode_length(buf, sk->xlen);
memcpy(buf, sk->x, sk->xlen);
buf += sk->xlen;
/* parameters */
if (include_curve_oid) {
*buf ++ = 0xA0;
*buf ++ = oid[0] + 2;
*buf ++ = 0x06;
memcpy(buf, oid, oid[0] + 1);
buf += oid[0] + 1;
}
/* publicKey */
if (pk != NULL) {
*buf ++ = 0xA1;
buf += br_asn1_encode_length(buf, len_publicKey_bits);
*buf ++ = 0x03;
buf += br_asn1_encode_length(buf, pk->qlen + 1);
*buf ++ = 0x00;
memcpy(buf, pk->q, pk->qlen);
/* buf += pk->qlen; */
}
return 1 + lenlen + len_seq;
}
}
/* see bearssl_x509.h */
size_t
br_encode_ec_raw_der(void *dest,
const br_ec_private_key *sk, const br_ec_public_key *pk)
{
return br_encode_ec_raw_der_inner(dest, sk, pk, 1);
}