Head

GCC Code Coverage Report

Directory:	./		Exec	Total	Coverage
File:	lib/libcrypto/crypto/../../libssl/src/crypto/ec/ec2_oct.c	Lines:	69	188	36.7 %
Date:	2016-12-06	Branches:	42	154	27.3 %


/* $OpenBSD: ec2_oct.c,v 1.7 2015/02/09 15:49:22 jsing Exp $ */
/* ====================================================================
 * Copyright 2002 Sun Microsystems, Inc. ALL RIGHTS RESERVED.
 *
 * The Elliptic Curve Public-Key Crypto Library (ECC Code) included
 * herein is developed by SUN MICROSYSTEMS, INC., and is contributed
 * to the OpenSSL project.
 *
 * The ECC Code is licensed pursuant to the OpenSSL open source
 * license provided below.
 *
 * The software is originally written by Sheueling Chang Shantz and
 * Douglas Stebila of Sun Microsystems Laboratories.
 *
 */
/* ====================================================================
 * Copyright (c) 1998-2005 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/opensslconf.h>

#include <openssl/err.h>

#include "ec_lcl.h"

#ifndef OPENSSL_NO_EC2M

/* Calculates and sets the affine coordinates of an EC_POINT from the given
 * compressed coordinates.  Uses algorithm 2.3.4 of SEC 1.
 * Note that the simple implementation only uses affine coordinates.
 *
 * The method is from the following publication:
 *
 *     Harper, Menezes, Vanstone:
 *     "Public-Key Cryptosystems with Very Small Key Lengths",
 *     EUROCRYPT '92, Springer-Verlag LNCS 658,
 *     published February 1993
 *
 * US Patents 6,141,420 and 6,618,483 (Vanstone, Mullin, Agnew) describe
 * the same method, but claim no priority date earlier than July 29, 1994
 * (and additionally fail to cite the EUROCRYPT '92 publication as prior art).
 */
int
ec_GF2m_simple_set_compressed_coordinates(const EC_GROUP *group, EC_POINT *point,
    const BIGNUM *x_, int y_bit, BN_CTX *ctx)
{
	BN_CTX *new_ctx = NULL;
	BIGNUM *tmp, *x, *y, *z;
	int ret = 0, z0;

	/* clear error queue */
	ERR_clear_error();

	if (ctx == NULL) {
		ctx = new_ctx = BN_CTX_new();
		if (ctx == NULL)
			return 0;
	}
	y_bit = (y_bit != 0) ? 1 : 0;

	BN_CTX_start(ctx);
	if ((tmp = BN_CTX_get(ctx)) == NULL)
		goto err;
	if ((x = BN_CTX_get(ctx)) == NULL)
		goto err;
	if ((y = BN_CTX_get(ctx)) == NULL)
		goto err;
	if ((z = BN_CTX_get(ctx)) == NULL)
		goto err;

	if (!BN_GF2m_mod_arr(x, x_, group->poly))
		goto err;
	if (BN_is_zero(x)) {
		if (!BN_GF2m_mod_sqrt_arr(y, &group->b, group->poly, ctx))
			goto err;
	} else {
		if (!group->meth->field_sqr(group, tmp, x, ctx))
			goto err;
		if (!group->meth->field_div(group, tmp, &group->b, tmp, ctx))
			goto err;
		if (!BN_GF2m_add(tmp, &group->a, tmp))
			goto err;
		if (!BN_GF2m_add(tmp, x, tmp))
			goto err;
		if (!BN_GF2m_mod_solve_quad_arr(z, tmp, group->poly, ctx)) {
			unsigned long err = ERR_peek_last_error();

			if (ERR_GET_LIB(err) == ERR_LIB_BN &&
			    ERR_GET_REASON(err) == BN_R_NO_SOLUTION) {
				ERR_clear_error();
				ECerr(EC_F_EC_GF2M_SIMPLE_SET_COMPRESSED_COORDINATES, EC_R_INVALID_COMPRESSED_POINT);
			} else
				ECerr(EC_F_EC_GF2M_SIMPLE_SET_COMPRESSED_COORDINATES, ERR_R_BN_LIB);
			goto err;
		}
		z0 = (BN_is_odd(z)) ? 1 : 0;
		if (!group->meth->field_mul(group, y, x, z, ctx))
			goto err;
		if (z0 != y_bit) {
			if (!BN_GF2m_add(y, y, x))
				goto err;
		}
	}

	if (!EC_POINT_set_affine_coordinates_GF2m(group, point, x, y, ctx))
		goto err;

	ret = 1;

err:
	BN_CTX_end(ctx);
	BN_CTX_free(new_ctx);
	return ret;
}


/* Converts an EC_POINT to an octet string.
 * If buf is NULL, the encoded length will be returned.
 * If the length len of buf is smaller than required an error will be returned.
 */
size_t
ec_GF2m_simple_point2oct(const EC_GROUP *group, const EC_POINT *point,
    point_conversion_form_t form,
    unsigned char *buf, size_t len, BN_CTX * ctx)
{
	size_t ret;
	BN_CTX *new_ctx = NULL;
	int used_ctx = 0;
	BIGNUM *x, *y, *yxi;
	size_t field_len, i, skip;

	if ((form != POINT_CONVERSION_COMPRESSED)
	    && (form != POINT_CONVERSION_UNCOMPRESSED)
	    && (form != POINT_CONVERSION_HYBRID)) {
		ECerr(EC_F_EC_GF2M_SIMPLE_POINT2OCT, EC_R_INVALID_FORM);
		goto err;
	}
	if (EC_POINT_is_at_infinity(group, point) > 0) {
		/* encodes to a single 0 octet */
		if (buf != NULL) {
			if (len < 1) {
				ECerr(EC_F_EC_GF2M_SIMPLE_POINT2OCT, EC_R_BUFFER_TOO_SMALL);
				return 0;
			}
			buf[0] = 0;
		}
		return 1;
	}
	/* ret := required output buffer length */
	field_len = (EC_GROUP_get_degree(group) + 7) / 8;
	ret = (form == POINT_CONVERSION_COMPRESSED) ? 1 + field_len :
	    1 + 2 * field_len;

	/* if 'buf' is NULL, just return required length */
	if (buf != NULL) {
		if (len < ret) {
			ECerr(EC_F_EC_GF2M_SIMPLE_POINT2OCT, EC_R_BUFFER_TOO_SMALL);
			goto err;
		}
		if (ctx == NULL) {
			ctx = new_ctx = BN_CTX_new();
			if (ctx == NULL)
				return 0;
		}
		BN_CTX_start(ctx);
		used_ctx = 1;
		if ((x = BN_CTX_get(ctx)) == NULL)
			goto err;
		if ((y = BN_CTX_get(ctx)) == NULL)
			goto err;
		if ((yxi = BN_CTX_get(ctx)) == NULL)
			goto err;

		if (!EC_POINT_get_affine_coordinates_GF2m(group, point, x, y, ctx))
			goto err;

		buf[0] = form;
		if ((form != POINT_CONVERSION_UNCOMPRESSED) && !BN_is_zero(x)) {
			if (!group->meth->field_div(group, yxi, y, x, ctx))
				goto err;
			if (BN_is_odd(yxi))
				buf[0]++;
		}
		i = 1;

		skip = field_len - BN_num_bytes(x);
		if (skip > field_len) {
			ECerr(EC_F_EC_GF2M_SIMPLE_POINT2OCT, ERR_R_INTERNAL_ERROR);
			goto err;
		}
		while (skip > 0) {
			buf[i++] = 0;
			skip--;
		}
		skip = BN_bn2bin(x, buf + i);
		i += skip;
		if (i != 1 + field_len) {
			ECerr(EC_F_EC_GF2M_SIMPLE_POINT2OCT, ERR_R_INTERNAL_ERROR);
			goto err;
		}
		if (form == POINT_CONVERSION_UNCOMPRESSED ||
		    form == POINT_CONVERSION_HYBRID) {
			skip = field_len - BN_num_bytes(y);
			if (skip > field_len) {
				ECerr(EC_F_EC_GF2M_SIMPLE_POINT2OCT, ERR_R_INTERNAL_ERROR);
				goto err;
			}
			while (skip > 0) {
				buf[i++] = 0;
				skip--;
			}
			skip = BN_bn2bin(y, buf + i);
			i += skip;
		}
		if (i != ret) {
			ECerr(EC_F_EC_GF2M_SIMPLE_POINT2OCT, ERR_R_INTERNAL_ERROR);
			goto err;
		}
	}
	if (used_ctx)
		BN_CTX_end(ctx);
	BN_CTX_free(new_ctx);
	return ret;

err:
	if (used_ctx)
		BN_CTX_end(ctx);
	BN_CTX_free(new_ctx);
	return 0;
}


/* Converts an octet string representation to an EC_POINT.
 * Note that the simple implementation only uses affine coordinates.
 */
int
ec_GF2m_simple_oct2point(const EC_GROUP *group, EC_POINT *point,
    const unsigned char *buf, size_t len, BN_CTX *ctx)
{
	point_conversion_form_t form;
	int y_bit;
	BN_CTX *new_ctx = NULL;
	BIGNUM *x, *y, *yxi;
	size_t field_len, enc_len;
	int ret = 0;

	if (len == 0) {
		ECerr(EC_F_EC_GF2M_SIMPLE_OCT2POINT, EC_R_BUFFER_TOO_SMALL);
		return 0;
	}
	form = buf[0];
	y_bit = form & 1;
	form = form & ~1U;
	if ((form != 0) && (form != POINT_CONVERSION_COMPRESSED) &&
	    (form != POINT_CONVERSION_UNCOMPRESSED) &&
	    (form != POINT_CONVERSION_HYBRID)) {
		ECerr(EC_F_EC_GF2M_SIMPLE_OCT2POINT, EC_R_INVALID_ENCODING);
		return 0;
	}
	if ((form == 0 || form == POINT_CONVERSION_UNCOMPRESSED) && y_bit) {
		ECerr(EC_F_EC_GF2M_SIMPLE_OCT2POINT, EC_R_INVALID_ENCODING);
		return 0;
	}
	if (form == 0) {
		if (len != 1) {
			ECerr(EC_F_EC_GF2M_SIMPLE_OCT2POINT, EC_R_INVALID_ENCODING);
			return 0;
		}
		return EC_POINT_set_to_infinity(group, point);
	}
	field_len = (EC_GROUP_get_degree(group) + 7) / 8;
	enc_len = (form == POINT_CONVERSION_COMPRESSED) ? 1 + field_len :
	    1 + 2 * field_len;

	if (len != enc_len) {
		ECerr(EC_F_EC_GF2M_SIMPLE_OCT2POINT, EC_R_INVALID_ENCODING);
		return 0;
	}
	if (ctx == NULL) {
		ctx = new_ctx = BN_CTX_new();
		if (ctx == NULL)
			return 0;
	}
	BN_CTX_start(ctx);
	if ((x = BN_CTX_get(ctx)) == NULL)
		goto err;
	if ((y = BN_CTX_get(ctx)) == NULL)
		goto err;
	if ((yxi = BN_CTX_get(ctx)) == NULL)
		goto err;

	if (!BN_bin2bn(buf + 1, field_len, x))
		goto err;
	if (BN_ucmp(x, &group->field) >= 0) {
		ECerr(EC_F_EC_GF2M_SIMPLE_OCT2POINT, EC_R_INVALID_ENCODING);
		goto err;
	}
	if (form == POINT_CONVERSION_COMPRESSED) {
		if (!EC_POINT_set_compressed_coordinates_GF2m(group, point, x, y_bit, ctx))
			goto err;
	} else {
		if (!BN_bin2bn(buf + 1 + field_len, field_len, y))
			goto err;
		if (BN_ucmp(y, &group->field) >= 0) {
			ECerr(EC_F_EC_GF2M_SIMPLE_OCT2POINT, EC_R_INVALID_ENCODING);
			goto err;
		}
		if (form == POINT_CONVERSION_HYBRID) {
			if (!group->meth->field_div(group, yxi, y, x, ctx))
				goto err;
			if (y_bit != BN_is_odd(yxi)) {
				ECerr(EC_F_EC_GF2M_SIMPLE_OCT2POINT, EC_R_INVALID_ENCODING);
				goto err;
			}
		}
		if (!EC_POINT_set_affine_coordinates_GF2m(group, point, x, y, ctx))
			goto err;
	}

	/* test required by X9.62 */
	if (EC_POINT_is_on_curve(group, point, ctx) <= 0) {
		ECerr(EC_F_EC_GF2M_SIMPLE_OCT2POINT, EC_R_POINT_IS_NOT_ON_CURVE);
		goto err;
	}
	ret = 1;

err:
	BN_CTX_end(ctx);
	BN_CTX_free(new_ctx);
	return ret;
}
#endif


Generated by: GCOVR (Version 3.3)

Line	Branch	Exec	Source
1			/* $OpenBSD: ec2_oct.c,v 1.7 2015/02/09 15:49:22 jsing Exp $ */
2			/* ====================================================================
3			* Copyright 2002 Sun Microsystems, Inc. ALL RIGHTS RESERVED.
4			*
5			* The Elliptic Curve Public-Key Crypto Library (ECC Code) included
6			* herein is developed by SUN MICROSYSTEMS, INC., and is contributed
7			* to the OpenSSL project.
8			*
9			* The ECC Code is licensed pursuant to the OpenSSL open source
10			* license provided below.
11			*
12			* The software is originally written by Sheueling Chang Shantz and
13			* Douglas Stebila of Sun Microsystems Laboratories.
14			*
15			*/
16			/* ====================================================================
17			* Copyright (c) 1998-2005 The OpenSSL Project. All rights reserved.
18			*
19			* Redistribution and use in source and binary forms, with or without
20			* modification, are permitted provided that the following conditions
21			* are met:
22			*
23			* 1. Redistributions of source code must retain the above copyright
24			* notice, this list of conditions and the following disclaimer.
25			*
26			* 2. Redistributions in binary form must reproduce the above copyright
27			* notice, this list of conditions and the following disclaimer in
28			* the documentation and/or other materials provided with the
29			* distribution.
30			*
31			* 3. All advertising materials mentioning features or use of this
32			* software must display the following acknowledgment:
33			* "This product includes software developed by the OpenSSL Project
34			* for use in the OpenSSL Toolkit. (http://www.openssl.org/)"
35			*
36			* 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
37			* endorse or promote products derived from this software without
38			* prior written permission. For written permission, please contact
39			* openssl-core@openssl.org.
40			*
41			* 5. Products derived from this software may not be called "OpenSSL"
42			* nor may "OpenSSL" appear in their names without prior written
43			* permission of the OpenSSL Project.
44			*
45			* 6. Redistributions of any form whatsoever must retain the following
46			* acknowledgment:
47			* "This product includes software developed by the OpenSSL Project
48			* for use in the OpenSSL Toolkit (http://www.openssl.org/)"
49			*
50			* THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
51			* EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
52			* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
53			* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR
54			* ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
55			* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
56			* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
57			* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
58			* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
59			* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
60			* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
61			* OF THE POSSIBILITY OF SUCH DAMAGE.
62			* ====================================================================
63			*
64			* This product includes cryptographic software written by Eric Young
65			* (eay@cryptsoft.com). This product includes software written by Tim
66			* Hudson (tjh@cryptsoft.com).
67			*
68			*/
69
70			#include <openssl/opensslconf.h>
71
72			#include <openssl/err.h>
73
74			#include "ec_lcl.h"
75
76			#ifndef OPENSSL_NO_EC2M
77
78			/* Calculates and sets the affine coordinates of an EC_POINT from the given
79			* compressed coordinates. Uses algorithm 2.3.4 of SEC 1.
80			* Note that the simple implementation only uses affine coordinates.
81			*
82			* The method is from the following publication:
83			*
84			* Harper, Menezes, Vanstone:
85			* "Public-Key Cryptosystems with Very Small Key Lengths",
86			* EUROCRYPT '92, Springer-Verlag LNCS 658,
87			* published February 1993
88			*
89			* US Patents 6,141,420 and 6,618,483 (Vanstone, Mullin, Agnew) describe
90			* the same method, but claim no priority date earlier than July 29, 1994
91			* (and additionally fail to cite the EUROCRYPT '92 publication as prior art).
92			*/
93			int
94			ec_GF2m_simple_set_compressed_coordinates(const EC_GROUP group, EC_POINT point,
95			const BIGNUM x_, int y_bit, BN_CTX ctx)
96			{
97			BN_CTX *new_ctx = NULL;
98			BIGNUM tmp, x, y, z;
99			int ret = 0, z0;
100
101			/* clear error queue */
102			ERR_clear_error();
103
104			if (ctx == NULL) {
105			ctx = new_ctx = BN_CTX_new();
106			if (ctx == NULL)
107			return 0;
108			}
109			y_bit = (y_bit != 0) ? 1 : 0;
110
111			BN_CTX_start(ctx);
112			if ((tmp = BN_CTX_get(ctx)) == NULL)
113			goto err;
114			if ((x = BN_CTX_get(ctx)) == NULL)
115			goto err;
116			if ((y = BN_CTX_get(ctx)) == NULL)
117			goto err;
118			if ((z = BN_CTX_get(ctx)) == NULL)
119			goto err;
120
121			if (!BN_GF2m_mod_arr(x, x_, group->poly))
122			goto err;
123			if (BN_is_zero(x)) {
124			if (!BN_GF2m_mod_sqrt_arr(y, &group->b, group->poly, ctx))
125			goto err;
126			} else {
127			if (!group->meth->field_sqr(group, tmp, x, ctx))
128			goto err;
129			if (!group->meth->field_div(group, tmp, &group->b, tmp, ctx))
130			goto err;
131			if (!BN_GF2m_add(tmp, &group->a, tmp))
132			goto err;
133			if (!BN_GF2m_add(tmp, x, tmp))
134			goto err;
135			if (!BN_GF2m_mod_solve_quad_arr(z, tmp, group->poly, ctx)) {
136			unsigned long err = ERR_peek_last_error();
137
138			if (ERR_GET_LIB(err) == ERR_LIB_BN &&
139			ERR_GET_REASON(err) == BN_R_NO_SOLUTION) {
140			ERR_clear_error();
141			ECerr(EC_F_EC_GF2M_SIMPLE_SET_COMPRESSED_COORDINATES, EC_R_INVALID_COMPRESSED_POINT);
142			} else
143			ECerr(EC_F_EC_GF2M_SIMPLE_SET_COMPRESSED_COORDINATES, ERR_R_BN_LIB);
144			goto err;
145			}
146			z0 = (BN_is_odd(z)) ? 1 : 0;
147			if (!group->meth->field_mul(group, y, x, z, ctx))
148			goto err;
149			if (z0 != y_bit) {
150			if (!BN_GF2m_add(y, y, x))
151			goto err;
152			}
153			}
154
155			if (!EC_POINT_set_affine_coordinates_GF2m(group, point, x, y, ctx))
156			goto err;
157
158			ret = 1;
159
160			err:
161			BN_CTX_end(ctx);
162			BN_CTX_free(new_ctx);
163			return ret;
164			}
165
166
167			/* Converts an EC_POINT to an octet string.
168			* If buf is NULL, the encoded length will be returned.
169			* If the length len of buf is smaller than required an error will be returned.
170			*/
171			size_t
172			ec_GF2m_simple_point2oct(const EC_GROUP group, const EC_POINT point,
173			point_conversion_form_t form,
174			unsigned char buf, size_t len, BN_CTX ctx)
175		1	{
176			size_t ret;
177		1	BN_CTX *new_ctx = NULL;
178		1	int used_ctx = 0;
179			BIGNUM x, y, *yxi;
180			size_t field_len, i, skip;
181
182	✗✓✗✗	1	if ((form != POINT_CONVERSION_COMPRESSED)
183			&& (form != POINT_CONVERSION_UNCOMPRESSED)
184			&& (form != POINT_CONVERSION_HYBRID)) {
185			ECerr(EC_F_EC_GF2M_SIMPLE_POINT2OCT, EC_R_INVALID_FORM);
186			goto err;
187			}
188	✗✓	1	if (EC_POINT_is_at_infinity(group, point) > 0) {
189			/* encodes to a single 0 octet */
190			if (buf != NULL) {
191			if (len < 1) {
192			ECerr(EC_F_EC_GF2M_SIMPLE_POINT2OCT, EC_R_BUFFER_TOO_SMALL);
193			return 0;
194			}
195			buf[0] = 0;
196			}
197			return 1;
198			}
199			/* ret := required output buffer length */
200		1	field_len = (EC_GROUP_get_degree(group) + 7) / 8;
201	✗✓	1	ret = (form == POINT_CONVERSION_COMPRESSED) ? 1 + field_len :
202			1 + 2 * field_len;
203
204			/* if 'buf' is NULL, just return required length */
205	✓✗	1	if (buf != NULL) {
206	✗✓	1	if (len < ret) {
207			ECerr(EC_F_EC_GF2M_SIMPLE_POINT2OCT, EC_R_BUFFER_TOO_SMALL);
208			goto err;
209			}
210	✗✓	1	if (ctx == NULL) {
211			ctx = new_ctx = BN_CTX_new();
212			if (ctx == NULL)
213			return 0;
214			}
215		1	BN_CTX_start(ctx);
216		1	used_ctx = 1;
217	✗✓	1	if ((x = BN_CTX_get(ctx)) == NULL)
218			goto err;
219	✗✓	1	if ((y = BN_CTX_get(ctx)) == NULL)
220			goto err;
221	✗✓	1	if ((yxi = BN_CTX_get(ctx)) == NULL)
222			goto err;
223
224	✗✓	1	if (!EC_POINT_get_affine_coordinates_GF2m(group, point, x, y, ctx))
225			goto err;
226
227		1	buf[0] = form;
228	✗✓✗✗	1	if ((form != POINT_CONVERSION_UNCOMPRESSED) && !BN_is_zero(x)) {
229			if (!group->meth->field_div(group, yxi, y, x, ctx))
230			goto err;
231			if (BN_is_odd(yxi))
232			buf[0]++;
233			}
234		1	i = 1;
235
236		1	skip = field_len - BN_num_bytes(x);
237	✗✓	1	if (skip > field_len) {
238			ECerr(EC_F_EC_GF2M_SIMPLE_POINT2OCT, ERR_R_INTERNAL_ERROR);
239			goto err;
240			}
241	✗✓	1	while (skip > 0) {
242			buf[i++] = 0;
243			skip--;
244			}
245		1	skip = BN_bn2bin(x, buf + i);
246		1	i += skip;
247	✗✓	1	if (i != 1 + field_len) {
248			ECerr(EC_F_EC_GF2M_SIMPLE_POINT2OCT, ERR_R_INTERNAL_ERROR);
249			goto err;
250			}
251	✓✗	1	if (form == POINT_CONVERSION_UNCOMPRESSED \|\|
252			form == POINT_CONVERSION_HYBRID) {
253		1	skip = field_len - BN_num_bytes(y);
254	✗✓	1	if (skip > field_len) {
255			ECerr(EC_F_EC_GF2M_SIMPLE_POINT2OCT, ERR_R_INTERNAL_ERROR);
256			goto err;
257			}
258	✗✓	1	while (skip > 0) {
259			buf[i++] = 0;
260			skip--;
261			}
262		1	skip = BN_bn2bin(y, buf + i);
263		1	i += skip;
264			}
265	✗✓	1	if (i != ret) {
266			ECerr(EC_F_EC_GF2M_SIMPLE_POINT2OCT, ERR_R_INTERNAL_ERROR);
267			goto err;
268			}
269			}
270	✓✗	1	if (used_ctx)
271		1	BN_CTX_end(ctx);
272		1	BN_CTX_free(new_ctx);
273		1	return ret;
274
275			err:
276			if (used_ctx)
277			BN_CTX_end(ctx);
278			BN_CTX_free(new_ctx);
279			return 0;
280			}
281
282
283			/* Converts an octet string representation to an EC_POINT.
284			* Note that the simple implementation only uses affine coordinates.
285			*/
286			int
287			ec_GF2m_simple_oct2point(const EC_GROUP group, EC_POINT point,
288			const unsigned char buf, size_t len, BN_CTX ctx)
289		2	{
290			point_conversion_form_t form;
291			int y_bit;
292		2	BN_CTX *new_ctx = NULL;
293			BIGNUM x, y, *yxi;
294			size_t field_len, enc_len;
295		2	int ret = 0;
296
297	✗✓	2	if (len == 0) {
298			ECerr(EC_F_EC_GF2M_SIMPLE_OCT2POINT, EC_R_BUFFER_TOO_SMALL);
299			return 0;
300			}
301		2	form = buf[0];
302		2	y_bit = form & 1;
303		2	form = form & ~1U;
304	✓✓✗✓	2	if ((form != 0) && (form != POINT_CONVERSION_COMPRESSED) &&
305			(form != POINT_CONVERSION_UNCOMPRESSED) &&
306			(form != POINT_CONVERSION_HYBRID)) {
307			ECerr(EC_F_EC_GF2M_SIMPLE_OCT2POINT, EC_R_INVALID_ENCODING);
308			return 0;
309			}
310	✓✗✗✓	2	if ((form == 0 \|\| form == POINT_CONVERSION_UNCOMPRESSED) && y_bit) {
311			ECerr(EC_F_EC_GF2M_SIMPLE_OCT2POINT, EC_R_INVALID_ENCODING);
312			return 0;
313			}
314	✓✓	2	if (form == 0) {
315	✗✓	1	if (len != 1) {
316			ECerr(EC_F_EC_GF2M_SIMPLE_OCT2POINT, EC_R_INVALID_ENCODING);
317			return 0;
318			}
319		1	return EC_POINT_set_to_infinity(group, point);
320			}
321		1	field_len = (EC_GROUP_get_degree(group) + 7) / 8;
322	✗✓	1	enc_len = (form == POINT_CONVERSION_COMPRESSED) ? 1 + field_len :
323			1 + 2 * field_len;
324
325	✗✓	1	if (len != enc_len) {
326			ECerr(EC_F_EC_GF2M_SIMPLE_OCT2POINT, EC_R_INVALID_ENCODING);
327			return 0;
328			}
329	✗✓	1	if (ctx == NULL) {
330			ctx = new_ctx = BN_CTX_new();
331			if (ctx == NULL)
332			return 0;
333			}
334		1	BN_CTX_start(ctx);
335	✗✓	1	if ((x = BN_CTX_get(ctx)) == NULL)
336			goto err;
337	✗✓	1	if ((y = BN_CTX_get(ctx)) == NULL)
338			goto err;
339	✗✓	1	if ((yxi = BN_CTX_get(ctx)) == NULL)
340			goto err;
341
342	✗✓	1	if (!BN_bin2bn(buf + 1, field_len, x))
343			goto err;
344	✗✓	1	if (BN_ucmp(x, &group->field) >= 0) {
345			ECerr(EC_F_EC_GF2M_SIMPLE_OCT2POINT, EC_R_INVALID_ENCODING);
346			goto err;
347			}
348	✗✓	1	if (form == POINT_CONVERSION_COMPRESSED) {
349			if (!EC_POINT_set_compressed_coordinates_GF2m(group, point, x, y_bit, ctx))
350			goto err;
351			} else {
352	✗✓	1	if (!BN_bin2bn(buf + 1 + field_len, field_len, y))
353			goto err;
354	✗✓	1	if (BN_ucmp(y, &group->field) >= 0) {
355			ECerr(EC_F_EC_GF2M_SIMPLE_OCT2POINT, EC_R_INVALID_ENCODING);
356			goto err;
357			}
358	✗✓	1	if (form == POINT_CONVERSION_HYBRID) {
359			if (!group->meth->field_div(group, yxi, y, x, ctx))
360			goto err;
361			if (y_bit != BN_is_odd(yxi)) {
362			ECerr(EC_F_EC_GF2M_SIMPLE_OCT2POINT, EC_R_INVALID_ENCODING);
363			goto err;
364			}
365			}
366	✗✓	1	if (!EC_POINT_set_affine_coordinates_GF2m(group, point, x, y, ctx))
367			goto err;
368			}
369
370			/* test required by X9.62 */
371	✗✓	1	if (EC_POINT_is_on_curve(group, point, ctx) <= 0) {
372			ECerr(EC_F_EC_GF2M_SIMPLE_OCT2POINT, EC_R_POINT_IS_NOT_ON_CURVE);
373			goto err;
374			}
375		1	ret = 1;
376
377		1	err:
378		1	BN_CTX_end(ctx);
379		1	BN_CTX_free(new_ctx);
380		1	return ret;
381			}
382			#endif