ec_print.c revision 1.12 
1/* $OpenBSD: ec_print.c,v 1.12 2023/06/23 10:34:16 tb Exp $ */
2/* ====================================================================
3 * Copyright (c) 1998-2002 The OpenSSL Project.  All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 *
9 * 1. Redistributions of source code must retain the above copyright
10 *    notice, this list of conditions and the following disclaimer.
11 *
12 * 2. Redistributions in binary form must reproduce the above copyright
13 *    notice, this list of conditions and the following disclaimer in
14 *    the documentation and/or other materials provided with the
15 *    distribution.
16 *
17 * 3. All advertising materials mentioning features or use of this
18 *    software must display the following acknowledgment:
19 *    "This product includes software developed by the OpenSSL Project
20 *    for use in the OpenSSL Toolkit. (http://www.openssl.org/)"
21 *
22 * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
23 *    endorse or promote products derived from this software without
24 *    prior written permission. For written permission, please contact
25 *    openssl-core@openssl.org.
26 *
27 * 5. Products derived from this software may not be called "OpenSSL"
28 *    nor may "OpenSSL" appear in their names without prior written
29 *    permission of the OpenSSL Project.
30 *
31 * 6. Redistributions of any form whatsoever must retain the following
32 *    acknowledgment:
33 *    "This product includes software developed by the OpenSSL Project
34 *    for use in the OpenSSL Toolkit (http://www.openssl.org/)"
35 *
36 * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
37 * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
38 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
39 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE OpenSSL PROJECT OR
40 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
41 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
42 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
43 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
44 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
45 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
46 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
47 * OF THE POSSIBILITY OF SUCH DAMAGE.
48 * ====================================================================
49 *
50 * This product includes cryptographic software written by Eric Young
51 * (eay@cryptsoft.com).  This product includes software written by Tim
52 * Hudson (tjh@cryptsoft.com).
53 *
54 */
55
56#include <openssl/crypto.h>
57#include "ec_local.h"
58
59BIGNUM *
60EC_POINT_point2bn(const EC_GROUP *group, const EC_POINT *point,
61    point_conversion_form_t form, BIGNUM *ret, BN_CTX *ctx)
62{
63	size_t buf_len = 0;
64	unsigned char *buf;
65
66	buf_len = EC_POINT_point2oct(group, point, form,
67	    NULL, 0, ctx);
68	if (buf_len == 0)
69		return NULL;
70
71	if ((buf = malloc(buf_len)) == NULL)
72		return NULL;
73
74	if (!EC_POINT_point2oct(group, point, form, buf, buf_len, ctx)) {
75		free(buf);
76		return NULL;
77	}
78	ret = BN_bin2bn(buf, buf_len, ret);
79
80	free(buf);
81
82	return ret;
83}
84
85EC_POINT *
86EC_POINT_bn2point(const EC_GROUP *group,
87    const BIGNUM *bn, EC_POINT *point, BN_CTX *ctx)
88{
89	size_t buf_len = 0;
90	unsigned char *buf;
91	EC_POINT *ret;
92
93	if ((buf_len = BN_num_bytes(bn)) == 0)
94		return NULL;
95	buf = malloc(buf_len);
96	if (buf == NULL)
97		return NULL;
98
99	if (!BN_bn2bin(bn, buf)) {
100		free(buf);
101		return NULL;
102	}
103	if (point == NULL) {
104		if ((ret = EC_POINT_new(group)) == NULL) {
105			free(buf);
106			return NULL;
107		}
108	} else
109		ret = point;
110
111	if (!EC_POINT_oct2point(group, ret, buf, buf_len, ctx)) {
112		if (point == NULL)
113			EC_POINT_free(ret);
114		free(buf);
115		return NULL;
116	}
117	free(buf);
118	return ret;
119}
120
121static const char *HEX_DIGITS = "0123456789ABCDEF";
122
123/* the return value must be freed (using free()) */
124char *
125EC_POINT_point2hex(const EC_GROUP *group, const EC_POINT *point,
126    point_conversion_form_t form, BN_CTX *ctx)
127{
128	char *ret, *p;
129	size_t buf_len = 0, i;
130	unsigned char *buf, *pbuf;
131
132	buf_len = EC_POINT_point2oct(group, point, form,
133	    NULL, 0, ctx);
134	if (buf_len == 0 || buf_len + 1 == 0)
135		return NULL;
136
137	if ((buf = malloc(buf_len)) == NULL)
138		return NULL;
139
140	if (!EC_POINT_point2oct(group, point, form, buf, buf_len, ctx)) {
141		free(buf);
142		return NULL;
143	}
144	ret = reallocarray(NULL, buf_len + 1, 2);
145	if (ret == NULL) {
146		free(buf);
147		return NULL;
148	}
149	p = ret;
150	pbuf = buf;
151	for (i = buf_len; i > 0; i--) {
152		int v = (int) *(pbuf++);
153		*(p++) = HEX_DIGITS[v >> 4];
154		*(p++) = HEX_DIGITS[v & 0x0F];
155	}
156	*p = '\0';
157
158	free(buf);
159
160	return ret;
161}
162
163EC_POINT *
164EC_POINT_hex2point(const EC_GROUP *group, const char *buf,
165    EC_POINT *point, BN_CTX *ctx)
166{
167	EC_POINT *ret = NULL;
168	BIGNUM *tmp_bn = NULL;
169
170	if (BN_hex2bn(&tmp_bn, buf) == 0)
171		return NULL;
172
173	ret = EC_POINT_bn2point(group, tmp_bn, point, ctx);
174
175	BN_free(tmp_bn);
176
177	return ret;
178}
179