/*
 * Copyright (C) Internet Systems Consortium, Inc. ("ISC")
 *
 * SPDX-License-Identifier: MPL-2.0
 *
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, you can obtain one at https://mozilla.org/MPL/2.0/.
 *
 * See the COPYRIGHT file distributed with this work for additional
 * information regarding copyright ownership.
 */

#include <stdio.h>

#include <openssl/err.h>
#include <openssl/evp.h>
#include <openssl/opensslv.h>

#include <isc/md.h>
#include <isc/util.h>

#include "openssl_shim.h"

isc_md_t *
isc_md_new(void) {
	isc_md_t *md = EVP_MD_CTX_new();
	RUNTIME_CHECK(md != NULL);
	return (md);
}

void
isc_md_free(isc_md_t *md) {
	if (md == NULL) {
		return;
	}

	EVP_MD_CTX_free(md);
}

isc_result_t
isc_md_init(isc_md_t *md, const isc_md_type_t *md_type) {
	REQUIRE(md != NULL);

	if (md_type == NULL) {
		return (ISC_R_NOTIMPLEMENTED);
	}

	if (EVP_DigestInit_ex(md, md_type, NULL) != 1) {
		ERR_clear_error();
		return (ISC_R_CRYPTOFAILURE);
	}

	return (ISC_R_SUCCESS);
}

isc_result_t
isc_md_reset(isc_md_t *md) {
	REQUIRE(md != NULL);

	if (EVP_MD_CTX_reset(md) != 1) {
		ERR_clear_error();
		return (ISC_R_CRYPTOFAILURE);
	}

	return (ISC_R_SUCCESS);
}

isc_result_t
isc_md_update(isc_md_t *md, const unsigned char *buf, const size_t len) {
	REQUIRE(md != NULL);

	if (buf == NULL || len == 0) {
		return (ISC_R_SUCCESS);
	}

	if (EVP_DigestUpdate(md, buf, len) != 1) {
		ERR_clear_error();
		return (ISC_R_CRYPTOFAILURE);
	}

	return (ISC_R_SUCCESS);
}

isc_result_t
isc_md_final(isc_md_t *md, unsigned char *digest, unsigned int *digestlen) {
	REQUIRE(md != NULL);
	REQUIRE(digest != NULL);

	if (EVP_DigestFinal_ex(md, digest, digestlen) != 1) {
		ERR_clear_error();
		return (ISC_R_CRYPTOFAILURE);
	}

	return (ISC_R_SUCCESS);
}

const isc_md_type_t *
isc_md_get_md_type(isc_md_t *md) {
	REQUIRE(md != NULL);

	return (EVP_MD_CTX_get0_md(md));
}

size_t
isc_md_get_size(isc_md_t *md) {
	REQUIRE(md != NULL);

	return (EVP_MD_CTX_size(md));
}

size_t
isc_md_get_block_size(isc_md_t *md) {
	REQUIRE(md != NULL);

	return (EVP_MD_CTX_block_size(md));
}

size_t
isc_md_type_get_size(const isc_md_type_t *md_type) {
	STATIC_ASSERT(ISC_MAX_MD_SIZE >= EVP_MAX_MD_SIZE,
		      "Change ISC_MAX_MD_SIZE to be greater than or equal to "
		      "EVP_MAX_MD_SIZE");
	if (md_type != NULL) {
		return ((size_t)EVP_MD_size(md_type));
	}

	return (ISC_MAX_MD_SIZE);
}

size_t
isc_md_type_get_block_size(const isc_md_type_t *md_type) {
	STATIC_ASSERT(ISC_MAX_MD_SIZE >= EVP_MAX_MD_SIZE,
		      "Change ISC_MAX_MD_SIZE to be greater than or equal to "
		      "EVP_MAX_MD_SIZE");
	if (md_type != NULL) {
		return ((size_t)EVP_MD_block_size(md_type));
	}

	return (ISC_MAX_MD_SIZE);
}

isc_result_t
isc_md(const isc_md_type_t *md_type, const unsigned char *buf, const size_t len,
       unsigned char *digest, unsigned int *digestlen) {
	isc_md_t *md;
	isc_result_t res;

	md = isc_md_new();

	res = isc_md_init(md, md_type);
	if (res != ISC_R_SUCCESS) {
		goto end;
	}

	res = isc_md_update(md, buf, len);
	if (res != ISC_R_SUCCESS) {
		goto end;
	}

	res = isc_md_final(md, digest, digestlen);
	if (res != ISC_R_SUCCESS) {
		goto end;
	}
end:
	isc_md_free(md);

	return (res);
}

#define md_register_algorithm(alg)                        \
	const isc_md_type_t *isc__md_##alg(void) {        \
		const isc_md_type_t *value = EVP_##alg(); \
		if (value == NULL) {                      \
			ERR_clear_error();                \
		}                                         \
		return (value);                           \
	}

md_register_algorithm(md5);
md_register_algorithm(sha1);
md_register_algorithm(sha224);
md_register_algorithm(sha256);
md_register_algorithm(sha384);
md_register_algorithm(sha512);