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/*
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDERS OR CONTRIBUTORS
* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
#include "ecdsa.h"
#include "utils.h"
#include <botan/ffi.h>
#include <string.h>
#include "bn.h"
static bool
ecdsa_load_public_key(botan_pubkey_t *pubkey, const pgp_ec_key_t *keydata)
{
botan_mp_t px = NULL;
botan_mp_t py = NULL;
bool res = false;
const ec_curve_desc_t *curve = get_curve_desc(keydata->curve);
if (!curve) {
RNP_LOG("unknown curve");
return false;
}
const size_t curve_order = BITS_TO_BYTES(curve->bitlen);
if (!mpi_bytes(&keydata->p) || (keydata->p.mpi[0] != 0x04)) {
RNP_LOG(
"Failed to load public key: %zu, %02x", mpi_bytes(&keydata->p), keydata->p.mpi[0]);
return false;
}
if (botan_mp_init(&px) || botan_mp_init(&py) ||
botan_mp_from_bin(px, &keydata->p.mpi[1], curve_order) ||
botan_mp_from_bin(py, &keydata->p.mpi[1 + curve_order], curve_order)) {
goto end;
}
if (!(res = !botan_pubkey_load_ecdsa(pubkey, px, py, curve->botan_name))) {
RNP_LOG("failed to load ecdsa public key");
}
end:
botan_mp_destroy(px);
botan_mp_destroy(py);
return res;
}
static bool
ecdsa_load_secret_key(botan_privkey_t *seckey, const pgp_ec_key_t *keydata)
{
const ec_curve_desc_t *curve;
bignum_t * x = NULL;
bool res = false;
if (!(curve = get_curve_desc(keydata->curve))) {
return false;
}
if (!(x = mpi2bn(&keydata->x))) {
return false;
}
if (!(res = !botan_privkey_load_ecdsa(seckey, BN_HANDLE_PTR(x), curve->botan_name))) {
RNP_LOG("Can't load private key");
}
bn_free(x);
return res;
}
rnp_result_t
ecdsa_validate_key(rnp::RNG *rng, const pgp_ec_key_t *key, bool secret)
{
botan_pubkey_t bpkey = NULL;
botan_privkey_t bskey = NULL;
rnp_result_t ret = RNP_ERROR_BAD_PARAMETERS;
if (!ecdsa_load_public_key(&bpkey, key) ||
botan_pubkey_check_key(bpkey, rng->handle(), 0)) {
goto done;
}
if (!secret) {
ret = RNP_SUCCESS;
goto done;
}
if (!ecdsa_load_secret_key(&bskey, key) ||
botan_privkey_check_key(bskey, rng->handle(), 0)) {
goto done;
}
ret = RNP_SUCCESS;
done:
botan_privkey_destroy(bskey);
botan_pubkey_destroy(bpkey);
return ret;
}
static const char *
ecdsa_padding_str_for(pgp_hash_alg_t hash_alg)
{
switch (hash_alg) {
case PGP_HASH_MD5:
return "Raw(MD5)";
case PGP_HASH_SHA1:
return "Raw(SHA-1)";
case PGP_HASH_RIPEMD:
return "Raw(RIPEMD-160)";
case PGP_HASH_SHA256:
return "Raw(SHA-256)";
case PGP_HASH_SHA384:
return "Raw(SHA-384)";
case PGP_HASH_SHA512:
return "Raw(SHA-512)";
case PGP_HASH_SHA224:
return "Raw(SHA-224)";
case PGP_HASH_SHA3_256:
return "Raw(SHA3(256))";
case PGP_HASH_SHA3_512:
return "Raw(SHA3(512))";
case PGP_HASH_SM3:
return "Raw(SM3)";
default:
return "Raw";
}
}
rnp_result_t
ecdsa_sign(rnp::RNG * rng,
pgp_ec_signature_t *sig,
pgp_hash_alg_t hash_alg,
const uint8_t * hash,
size_t hash_len,
const pgp_ec_key_t *key)
{
botan_pk_op_sign_t signer = NULL;
botan_privkey_t b_key = NULL;
rnp_result_t ret = RNP_ERROR_GENERIC;
uint8_t out_buf[2 * MAX_CURVE_BYTELEN] = {0};
const ec_curve_desc_t *curve = get_curve_desc(key->curve);
const char * padding_str = ecdsa_padding_str_for(hash_alg);
if (!curve) {
return RNP_ERROR_BAD_PARAMETERS;
}
const size_t curve_order = BITS_TO_BYTES(curve->bitlen);
size_t sig_len = 2 * curve_order;
if (!ecdsa_load_secret_key(&b_key, key)) {
RNP_LOG("Can't load private key");
goto end;
}
if (botan_pk_op_sign_create(&signer, b_key, padding_str, 0)) {
goto end;
}
if (botan_pk_op_sign_update(signer, hash, hash_len)) {
goto end;
}
if (botan_pk_op_sign_finish(signer, rng->handle(), out_buf, &sig_len)) {
RNP_LOG("Signing failed");
goto end;
}
// Allocate memory and copy results
if (mem2mpi(&sig->r, out_buf, curve_order) &&
mem2mpi(&sig->s, out_buf + curve_order, curve_order)) {
ret = RNP_SUCCESS;
}
end:
botan_privkey_destroy(b_key);
botan_pk_op_sign_destroy(signer);
return ret;
}
rnp_result_t
ecdsa_verify(const pgp_ec_signature_t *sig,
pgp_hash_alg_t hash_alg,
const uint8_t * hash,
size_t hash_len,
const pgp_ec_key_t * key)
{
botan_pubkey_t pub = NULL;
botan_pk_op_verify_t verifier = NULL;
rnp_result_t ret = RNP_ERROR_SIGNATURE_INVALID;
uint8_t sign_buf[2 * MAX_CURVE_BYTELEN] = {0};
size_t r_blen, s_blen;
const char * padding_str = ecdsa_padding_str_for(hash_alg);
const ec_curve_desc_t *curve = get_curve_desc(key->curve);
if (!curve) {
RNP_LOG("unknown curve");
return RNP_ERROR_BAD_PARAMETERS;
}
const size_t curve_order = BITS_TO_BYTES(curve->bitlen);
if (!ecdsa_load_public_key(&pub, key)) {
goto end;
}
if (botan_pk_op_verify_create(&verifier, pub, padding_str, 0)) {
goto end;
}
if (botan_pk_op_verify_update(verifier, hash, hash_len)) {
goto end;
}
r_blen = mpi_bytes(&sig->r);
s_blen = mpi_bytes(&sig->s);
if ((r_blen > curve_order) || (s_blen > curve_order) ||
(curve_order > MAX_CURVE_BYTELEN)) {
ret = RNP_ERROR_BAD_PARAMETERS;
goto end;
}
// Both can't fail
mpi2mem(&sig->r, &sign_buf[curve_order - r_blen]);
mpi2mem(&sig->s, &sign_buf[curve_order + curve_order - s_blen]);
if (!botan_pk_op_verify_finish(verifier, sign_buf, curve_order * 2)) {
ret = RNP_SUCCESS;
}
end:
botan_pubkey_destroy(pub);
botan_pk_op_verify_destroy(verifier);
return ret;
}
pgp_hash_alg_t
ecdsa_get_min_hash(pgp_curve_t curve)
{
switch (curve) {
case PGP_CURVE_NIST_P_256:
case PGP_CURVE_BP256:
case PGP_CURVE_P256K1:
return PGP_HASH_SHA256;
case PGP_CURVE_NIST_P_384:
case PGP_CURVE_BP384:
return PGP_HASH_SHA384;
case PGP_CURVE_NIST_P_521:
case PGP_CURVE_BP512:
return PGP_HASH_SHA512;
default:
return PGP_HASH_UNKNOWN;
}
}