/**
 * Copyright (c) 2013-2014 Tomas Dzetkulic
 * Copyright (c) 2013-2014 Pavol Rusnak
 *
 * 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.
 */

/* OpenSSL's SHA256_CTX/SHA512_CTX conflicts with our own */
#define SHA256_CTX _openssl_SHA256_CTX
#define SHA512_CTX _openssl_SHA512_CTX
#include <openssl/bn.h>
#include <openssl/ecdsa.h>
#include <openssl/obj_mac.h>
#include <openssl/sha.h>
#include <openssl/opensslv.h>
#undef SHA256_CTX
#undef SHA512_CTX

#include <stdio.h>
#include <stdint.h>
#include <string.h>

#include "ecdsa.h"
#include "rand.h"
#include "hasher.h"

#include "nist256p1.h"
#include "secp256k1.h"

#include "memzero.h"

void openssl_check(unsigned int iterations, int nid, const ecdsa_curve *curve)
{
	uint8_t sig[64], pub_key33[33], pub_key65[65], priv_key[32], msg[256], hash[32];
	struct SHA256state_st sha256;
	EC_GROUP *ecgroup;

	ecgroup = EC_GROUP_new_by_curve_name(nid);

	for (unsigned int iter = 0; iter < iterations; iter++) {

		// random message len between 1 and 256
		int msg_len = (random32() & 0xFF) + 1;
		// create random message
		random_buffer(msg, msg_len);

		// new ECDSA key
		EC_KEY *eckey = EC_KEY_new();
		EC_KEY_set_group(eckey, ecgroup);

		// generate the key
		EC_KEY_generate_key(eckey);
		// copy key to buffer
		const BIGNUM *K = EC_KEY_get0_private_key(eckey);
		int bn_off = sizeof(priv_key) - BN_num_bytes(K);
		memzero(priv_key, bn_off);
		BN_bn2bin(K, priv_key + bn_off);

		// use our ECDSA signer to sign the message with the key
		if (ecdsa_sign(curve, HASHER_SHA2, priv_key, msg, msg_len, sig, NULL, NULL) != 0) {
			printf("trezor-crypto signing failed\n");
			return;
		}

		// generate public key from private key
		ecdsa_get_public_key33(curve, priv_key, pub_key33);
		ecdsa_get_public_key65(curve, priv_key, pub_key65);

		// use our ECDSA verifier to verify the message signature
		if (ecdsa_verify(curve, HASHER_SHA2, pub_key65, sig, msg, msg_len) != 0) {
			printf("trezor-crypto verification failed (pub_key_len = 65)\n");
			return;
		}
		if (ecdsa_verify(curve, HASHER_SHA2, pub_key33, sig, msg, msg_len) != 0) {
			printf("trezor-crypto verification failed (pub_key_len = 33)\n");
			return;
		}

		// copy signature to the OpenSSL struct
		ECDSA_SIG *signature = ECDSA_SIG_new();
#if OPENSSL_VERSION_NUMBER  < 0x10100000L
		BN_bin2bn(sig, 32, signature->r);
		BN_bin2bn(sig + 32, 32, signature->s);
#else
		BIGNUM *R = BN_bin2bn(sig, 32, NULL);
		BIGNUM *S = BN_bin2bn(sig + 32, 32, NULL);
		ECDSA_SIG_set0(signature, R, S);
#endif

		// compute the digest of the message
		// note: these are OpenSSL functions, not our own
		SHA256_Init(&sha256);
		SHA256_Update(&sha256, msg, msg_len);
		SHA256_Final(hash, &sha256);

		// verify all went well, i.e. we can decrypt our signature with OpenSSL
		int v = ECDSA_do_verify(hash, 32, signature, eckey);
		if (v != 1) {
			printf("OpenSSL verification failed (%d)\n", v);
			return;
		}

		ECDSA_SIG_free(signature);
		EC_KEY_free(eckey);
		if (((iter + 1) % 100) == 0) printf("Passed ... %d\n", iter + 1);
	}
	EC_GROUP_free(ecgroup);
	printf("All OK\n");
}

int main(int argc, char *argv[])
{
	if (argc != 2) {
		printf("Usage: test_openssl iterations\n");
		return 1;
	}

	unsigned int iterations;
	sscanf(argv[1], "%u", &iterations);

	printf("Testing secp256k1:\n");
	openssl_check(iterations, NID_secp256k1, &secp256k1);

	printf("Testing nist256p1:\n");
	openssl_check(iterations, NID_X9_62_prime256v1, &nist256p1);

	return 0;
}