/* $OpenBSD: hm_ameth.c,v 1.12 2021/12/12 21:30:14 tb Exp $ */
/* Written by Dr Stephen N Henson (steve@openssl.org) for the OpenSSL
 * project 2007.
 */
/* ====================================================================
 * Copyright (c) 2007 The OpenSSL Project.  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.
 *
 * 3. All advertising materials mentioning features or use of this
 *    software must display the following acknowledgment:
 *    "This product includes software developed by the OpenSSL Project
 *    for use in the OpenSSL Toolkit. (http://www.OpenSSL.org/)"
 *
 * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
 *    endorse or promote products derived from this software without
 *    prior written permission. For written permission, please contact
 *    licensing@OpenSSL.org.
 *
 * 5. Products derived from this software may not be called "OpenSSL"
 *    nor may "OpenSSL" appear in their names without prior written
 *    permission of the OpenSSL Project.
 *
 * 6. Redistributions of any form whatsoever must retain the following
 *    acknowledgment:
 *    "This product includes software developed by the OpenSSL Project
 *    for use in the OpenSSL Toolkit (http://www.OpenSSL.org/)"
 *
 * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
 * EXPRESSED 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 OpenSSL PROJECT OR
 * ITS 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.
 * ====================================================================
 *
 * This product includes cryptographic software written by Eric Young
 * (eay@cryptsoft.com).  This product includes software written by Tim
 * Hudson (tjh@cryptsoft.com).
 *
 */

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

#include <openssl/evp.h>
#include <openssl/hmac.h>

#include "asn1_locl.h"
#include "evp_locl.h"
#include "hmac_local.h"

#define HMAC_TEST_PRIVATE_KEY_FORMAT

/* HMAC "ASN1" method. This is just here to indicate the
 * maximum HMAC output length and to free up an HMAC
 * key.
 */

static int
hmac_size(const EVP_PKEY *pkey)
{
	return EVP_MAX_MD_SIZE;
}

static void
hmac_key_free(EVP_PKEY *pkey)
{
	ASN1_OCTET_STRING *os = (ASN1_OCTET_STRING *)pkey->pkey.ptr;

	if (os) {
		if (os->data)
			explicit_bzero(os->data, os->length);
		ASN1_OCTET_STRING_free(os);
	}
}

static int
hmac_pkey_ctrl(EVP_PKEY *pkey, int op, long arg1, void *arg2)
{
	switch (op) {
	case ASN1_PKEY_CTRL_DEFAULT_MD_NID:
		*(int *)arg2 = NID_sha1;
		return 1;
	default:
		return -2;
	}
}

#ifdef HMAC_TEST_PRIVATE_KEY_FORMAT
/* A bogus private key format for test purposes. This is simply the
 * HMAC key with "HMAC PRIVATE KEY" in the headers. When enabled the
 * genpkey utility can be used to "generate" HMAC keys.
 */

static int
old_hmac_decode(EVP_PKEY *pkey, const unsigned char **pder, int derlen)
{
	ASN1_OCTET_STRING *os;

	os = ASN1_OCTET_STRING_new();
	if (os == NULL)
		goto err;
	if (ASN1_OCTET_STRING_set(os, *pder, derlen) == 0)
		goto err;
	if (EVP_PKEY_assign(pkey, EVP_PKEY_HMAC, os) == 0)
		goto err;
	return 1;

err:
	ASN1_OCTET_STRING_free(os);
	return 0;
}

static int
old_hmac_encode(const EVP_PKEY *pkey, unsigned char **pder)
{
	int inc;
	ASN1_OCTET_STRING *os = (ASN1_OCTET_STRING *)pkey->pkey.ptr;

	if (pder) {
		if (!*pder) {
			*pder = malloc(os->length);
			if (*pder == NULL)
				return -1;
			inc = 0;
		} else
			inc = 1;

		memcpy(*pder, os->data, os->length);

		if (inc)
			*pder += os->length;
	}

	return os->length;
}

#endif

const EVP_PKEY_ASN1_METHOD hmac_asn1_meth = {
	.pkey_id = EVP_PKEY_HMAC,
	.pkey_base_id = EVP_PKEY_HMAC,

	.pem_str = "HMAC",
	.info = "OpenSSL HMAC method",

	.pkey_size = hmac_size,

	.pkey_free = hmac_key_free,
	.pkey_ctrl = hmac_pkey_ctrl,
#ifdef HMAC_TEST_PRIVATE_KEY_FORMAT
	.old_priv_decode = old_hmac_decode,
	.old_priv_encode = old_hmac_encode
#endif
};
