/* $OpenBSD: ec_print.c,v 1.7 2014/12/03 19:53:20 deraadt Exp $ */
/* ====================================================================
 * 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 <openssl/crypto.h>
#include "ec_lcl.h"

BIGNUM *
EC_POINT_point2bn(const EC_GROUP * group, const EC_POINT * point,
    point_conversion_form_t form, BIGNUM * ret, BN_CTX * ctx)
{
	size_t buf_len = 0;
	unsigned char *buf;

	buf_len = EC_POINT_point2oct(group, point, form,
	    NULL, 0, ctx);
	if (buf_len == 0)
		return NULL;

	if ((buf = malloc(buf_len)) == NULL)
		return NULL;

	if (!EC_POINT_point2oct(group, point, form, buf, buf_len, ctx)) {
		free(buf);
		return NULL;
	}
	ret = BN_bin2bn(buf, buf_len, ret);

	free(buf);

	return ret;
}

EC_POINT *
EC_POINT_bn2point(const EC_GROUP * group,
    const BIGNUM * bn, EC_POINT * point, BN_CTX * ctx)
{
	size_t buf_len = 0;
	unsigned char *buf;
	EC_POINT *ret;

	if ((buf_len = BN_num_bytes(bn)) == 0)
		return NULL;
	buf = malloc(buf_len);
	if (buf == NULL)
		return NULL;

	if (!BN_bn2bin(bn, buf)) {
		free(buf);
		return NULL;
	}
	if (point == NULL) {
		if ((ret = EC_POINT_new(group)) == NULL) {
			free(buf);
			return NULL;
		}
	} else
		ret = point;

	if (!EC_POINT_oct2point(group, ret, buf, buf_len, ctx)) {
		if (point == NULL)
			EC_POINT_clear_free(ret);
		free(buf);
		return NULL;
	}
	free(buf);
	return ret;
}

static const char *HEX_DIGITS = "0123456789ABCDEF";

/* the return value must be freed (using free()) */
char *
EC_POINT_point2hex(const EC_GROUP * group, const EC_POINT * point,
    point_conversion_form_t form, BN_CTX * ctx)
{
	char *ret, *p;
	size_t buf_len = 0, i;
	unsigned char *buf, *pbuf;

	buf_len = EC_POINT_point2oct(group, point, form,
	    NULL, 0, ctx);
	if (buf_len == 0 || buf_len + 1 == 0)
		return NULL;

	if ((buf = malloc(buf_len)) == NULL)
		return NULL;

	if (!EC_POINT_point2oct(group, point, form, buf, buf_len, ctx)) {
		free(buf);
		return NULL;
	}
	ret = reallocarray(NULL, buf_len + 1, 2);
	if (ret == NULL) {
		free(buf);
		return NULL;
	}
	p = ret;
	pbuf = buf;
	for (i = buf_len; i > 0; i--) {
		int v = (int) *(pbuf++);
		*(p++) = HEX_DIGITS[v >> 4];
		*(p++) = HEX_DIGITS[v & 0x0F];
	}
	*p = '\0';

	free(buf);

	return ret;
}

EC_POINT *
EC_POINT_hex2point(const EC_GROUP * group, const char *buf,
    EC_POINT * point, BN_CTX * ctx)
{
	EC_POINT *ret = NULL;
	BIGNUM *tmp_bn = NULL;

	if (!BN_hex2bn(&tmp_bn, buf))
		return NULL;

	ret = EC_POINT_bn2point(group, tmp_bn, point, ctx);

	BN_clear_free(tmp_bn);

	return ret;
}
