/* $OpenBSD: ecs_vrf.c,v 1.6 2017/05/02 03:59:44 deraadt Exp $ */
/*
 * Written by Nils Larsch for the OpenSSL project
 */
/* ====================================================================
 * Copyright (c) 1998-2002 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
 *    openssl-core@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 <string.h>
#include <openssl/opensslconf.h>

#include "ecs_locl.h"
#ifndef OPENSSL_NO_ENGINE
#include <openssl/engine.h>
#endif

/* returns
 *      1: correct signature
 *      0: incorrect signature
 *     -1: error
 */
int
ECDSA_do_verify(const unsigned char *dgst, int dgst_len, const ECDSA_SIG *sig,
    EC_KEY *eckey)
{
	ECDSA_DATA *ecdsa = ecdsa_check(eckey);

	if (ecdsa == NULL)
		return 0;
	return ecdsa->meth->ecdsa_do_verify(dgst, dgst_len, sig, eckey);
}

/* returns
 *      1: correct signature
 *      0: incorrect signature
 *     -1: error
 */
int
ECDSA_verify(int type, const unsigned char *dgst, int dgst_len,
    const unsigned char *sigbuf, int sig_len, EC_KEY *eckey)
{
	ECDSA_SIG *s;
	unsigned char *der = NULL;
	const unsigned char *p = sigbuf;
	int derlen = -1;
	int ret = -1;

	s = ECDSA_SIG_new();
	if (s == NULL)
		return (ret);
	if (d2i_ECDSA_SIG(&s, &p, sig_len) == NULL)
		goto err;
	/* Ensure signature uses DER and doesn't have trailing garbage */
	derlen = i2d_ECDSA_SIG(s, &der);
	if (derlen != sig_len || memcmp(sigbuf, der, derlen))
		goto err;
	ret = ECDSA_do_verify(dgst, dgst_len, s, eckey);

err:
	freezero(der, derlen);
	ECDSA_SIG_free(s);
	return (ret);
}