[thirdparty/openssl.git] / crypto / ec / ecp_oct.c

/* crypto/ec/ecp_oct.c */
/*
 * Includes code written by Lenka Fibikova <fibikova@exp-math.uni-essen.de>
 * for the OpenSSL project. Includes code written by Bodo Moeller 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).
 *
 */
/* ====================================================================
 * Copyright 2002 Sun Microsystems, Inc. ALL RIGHTS RESERVED.
 * Portions of this software developed by SUN MICROSYSTEMS, INC.,
 * and contributed to the OpenSSL project.
 */

#include <openssl/err.h>
#include <openssl/symhacks.h>

#include "ec_lcl.h"

int ec_GFp_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 *tmp1, *tmp2, *x, *y;
    int ret = 0;

    /* 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);

    BN_CTX_start(ctx);
    tmp1 = BN_CTX_get(ctx);
    tmp2 = BN_CTX_get(ctx);
    x = BN_CTX_get(ctx);
    y = BN_CTX_get(ctx);
    if (y == NULL)
        goto err;

    /*-
     * Recover y.  We have a Weierstrass equation
     *     y^2 = x^3 + a*x + b,
     * so  y  is one of the square roots of  x^3 + a*x + b.
     */

    /* tmp1 := x^3 */
    if (!BN_nnmod(x, x_, group->field, ctx))
        goto err;
    if (group->meth->field_decode == 0) {
        /* field_{sqr,mul} work on standard representation */
        if (!group->meth->field_sqr(group, tmp2, x_, ctx))
            goto err;
        if (!group->meth->field_mul(group, tmp1, tmp2, x_, ctx))
            goto err;
    } else {
        if (!BN_mod_sqr(tmp2, x_, group->field, ctx))
            goto err;
        if (!BN_mod_mul(tmp1, tmp2, x_, group->field, ctx))
            goto err;
    }

    /* tmp1 := tmp1 + a*x */
    if (group->a_is_minus3) {
        if (!BN_mod_lshift1_quick(tmp2, x, group->field))
            goto err;
        if (!BN_mod_add_quick(tmp2, tmp2, x, group->field))
            goto err;
        if (!BN_mod_sub_quick(tmp1, tmp1, tmp2, group->field))
            goto err;
    } else {
        if (group->meth->field_decode) {
            if (!group->meth->field_decode(group, tmp2, group->a, ctx))
                goto err;
            if (!BN_mod_mul(tmp2, tmp2, x, group->field, ctx))
                goto err;
        } else {
            /* field_mul works on standard representation */
            if (!group->meth->field_mul(group, tmp2, group->a, x, ctx))
                goto err;
        }

        if (!BN_mod_add_quick(tmp1, tmp1, tmp2, group->field))
            goto err;
    }

    /* tmp1 := tmp1 + b */
    if (group->meth->field_decode) {
        if (!group->meth->field_decode(group, tmp2, group->b, ctx))
            goto err;
        if (!BN_mod_add_quick(tmp1, tmp1, tmp2, group->field))
            goto err;
    } else {
        if (!BN_mod_add_quick(tmp1, tmp1, group->b, group->field))
            goto err;
    }

    if (!BN_mod_sqrt(y, tmp1, group->field, ctx)) {
        unsigned long err = ERR_peek_last_error();

        if (ERR_GET_LIB(err) == ERR_LIB_BN
            && ERR_GET_REASON(err) == BN_R_NOT_A_SQUARE) {
            ERR_clear_error();
            ECerr(EC_F_EC_GFP_SIMPLE_SET_COMPRESSED_COORDINATES,
                  EC_R_INVALID_COMPRESSED_POINT);
        } else
            ECerr(EC_F_EC_GFP_SIMPLE_SET_COMPRESSED_COORDINATES,
                  ERR_R_BN_LIB);
        goto err;
    }

    if (y_bit != BN_is_odd(y)) {
        if (BN_is_zero(y)) {
            int kron;

            kron = BN_kronecker(x, group->field, ctx);
            if (kron == -2)
                goto err;

            if (kron == 1)
                ECerr(EC_F_EC_GFP_SIMPLE_SET_COMPRESSED_COORDINATES,
                      EC_R_INVALID_COMPRESSION_BIT);
            else
                /*
                 * BN_mod_sqrt() should have cought this error (not a square)
                 */
                ECerr(EC_F_EC_GFP_SIMPLE_SET_COMPRESSED_COORDINATES,
                      EC_R_INVALID_COMPRESSED_POINT);
            goto err;
        }
        if (!BN_usub(y, group->field, y))
            goto err;
    }
    if (y_bit != BN_is_odd(y)) {
        ECerr(EC_F_EC_GFP_SIMPLE_SET_COMPRESSED_COORDINATES,
              ERR_R_INTERNAL_ERROR);
        goto err;
    }

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

    ret = 1;

 err:
    BN_CTX_end(ctx);
    if (new_ctx != NULL)
        BN_CTX_free(new_ctx);
    return ret;
}

size_t ec_GFp_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;
    size_t field_len, i, skip;

    if ((form != POINT_CONVERSION_COMPRESSED)
        && (form != POINT_CONVERSION_UNCOMPRESSED)
        && (form != POINT_CONVERSION_HYBRID)) {
        ECerr(EC_F_EC_GFP_SIMPLE_POINT2OCT, EC_R_INVALID_FORM);
        goto err;
    }

    if (EC_POINT_is_at_infinity(group, point)) {
        /* encodes to a single 0 octet */
        if (buf != NULL) {
            if (len < 1) {
                ECerr(EC_F_EC_GFP_SIMPLE_POINT2OCT, EC_R_BUFFER_TOO_SMALL);
                return 0;
            }
            buf[0] = 0;
        }
        return 1;
    }

    /* ret := required output buffer length */
    field_len = BN_num_bytes(group->field);
    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_GFP_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;
        x = BN_CTX_get(ctx);
        y = BN_CTX_get(ctx);
        if (y == NULL)
            goto err;

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

        if ((form == POINT_CONVERSION_COMPRESSED
             || form == POINT_CONVERSION_HYBRID) && BN_is_odd(y))
            buf[0] = form + 1;
        else
            buf[0] = form;

        i = 1;

        skip = field_len - BN_num_bytes(x);
        if (skip > field_len) {
            ECerr(EC_F_EC_GFP_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_GFP_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_GFP_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_GFP_SIMPLE_POINT2OCT, ERR_R_INTERNAL_ERROR);
            goto err;
        }
    }

    if (used_ctx)
        BN_CTX_end(ctx);
    if (new_ctx != NULL)
        BN_CTX_free(new_ctx);
    return ret;

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

int ec_GFp_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;
    size_t field_len, enc_len;
    int ret = 0;

    if (len == 0) {
        ECerr(EC_F_EC_GFP_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_GFP_SIMPLE_OCT2POINT, EC_R_INVALID_ENCODING);
        return 0;
    }
    if ((form == 0 || form == POINT_CONVERSION_UNCOMPRESSED) && y_bit) {
        ECerr(EC_F_EC_GFP_SIMPLE_OCT2POINT, EC_R_INVALID_ENCODING);
        return 0;
    }

    if (form == 0) {
        if (len != 1) {
            ECerr(EC_F_EC_GFP_SIMPLE_OCT2POINT, EC_R_INVALID_ENCODING);
            return 0;
        }

        return EC_POINT_set_to_infinity(group, point);
    }

    field_len = BN_num_bytes(group->field);
    enc_len =
        (form ==
         POINT_CONVERSION_COMPRESSED) ? 1 + field_len : 1 + 2 * field_len;

    if (len != enc_len) {
        ECerr(EC_F_EC_GFP_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);
    x = BN_CTX_get(ctx);
    y = BN_CTX_get(ctx);
    if (y == NULL)
        goto err;

    if (!BN_bin2bn(buf + 1, field_len, x))
        goto err;
    if (BN_ucmp(x, group->field) >= 0) {
        ECerr(EC_F_EC_GFP_SIMPLE_OCT2POINT, EC_R_INVALID_ENCODING);
        goto err;
    }

    if (form == POINT_CONVERSION_COMPRESSED) {
        if (!EC_POINT_set_compressed_coordinates_GFp
            (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_GFP_SIMPLE_OCT2POINT, EC_R_INVALID_ENCODING);
            goto err;
        }
        if (form == POINT_CONVERSION_HYBRID) {
            if (y_bit != BN_is_odd(y)) {
                ECerr(EC_F_EC_GFP_SIMPLE_OCT2POINT, EC_R_INVALID_ENCODING);
                goto err;
            }
        }

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

    /* test required by X9.62 */
    if (!EC_POINT_is_on_curve(group, point, ctx)) {
        ECerr(EC_F_EC_GFP_SIMPLE_OCT2POINT, EC_R_POINT_IS_NOT_ON_CURVE);
        goto err;
    }

    ret = 1;

 err:
    BN_CTX_end(ctx);
    if (new_ctx != NULL)
        BN_CTX_free(new_ctx);
    return ret;
}
Commit	Line	Data
84b08eee	1	/* crypto/ec/ecp_oct.c */
0f113f3e MC	2	/*
	3	* Includes code written by Lenka Fibikova <fibikova@exp-math.uni-essen.de>
	4	* for the OpenSSL project. Includes code written by Bodo Moeller for the
	5	* OpenSSL project.
	6	*/
84b08eee DSH	7	/* ====================================================================
	8	* Copyright (c) 1998-2002 The OpenSSL Project. All rights reserved.
	9	*
	10	* Redistribution and use in source and binary forms, with or without
	11	* modification, are permitted provided that the following conditions
	12	* are met:
	13	*
	14	* 1. Redistributions of source code must retain the above copyright
0f113f3e	15	* notice, this list of conditions and the following disclaimer.
84b08eee DSH	16	*
	17	* 2. Redistributions in binary form must reproduce the above copyright
	18	* notice, this list of conditions and the following disclaimer in
	19	* the documentation and/or other materials provided with the
	20	* distribution.
	21	*
	22	* 3. All advertising materials mentioning features or use of this
	23	* software must display the following acknowledgment:
	24	* "This product includes software developed by the OpenSSL Project
	25	* for use in the OpenSSL Toolkit. (http://www.openssl.org/)"
	26	*
	27	* 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
	28	* endorse or promote products derived from this software without
	29	* prior written permission. For written permission, please contact
	30	* openssl-core@openssl.org.
	31	*
	32	* 5. Products derived from this software may not be called "OpenSSL"
	33	* nor may "OpenSSL" appear in their names without prior written
	34	* permission of the OpenSSL Project.
	35	*
	36	* 6. Redistributions of any form whatsoever must retain the following
	37	* acknowledgment:
	38	* "This product includes software developed by the OpenSSL Project
	39	* for use in the OpenSSL Toolkit (http://www.openssl.org/)"
	40	*
	41	* THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
	42	* EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
	43	* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
	44	* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR
	45	* ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
	46	* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
	47	* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
	48	* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
	49	* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
	50	* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
	51	* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
	52	* OF THE POSSIBILITY OF SUCH DAMAGE.
	53	* ====================================================================
	54	*
	55	* This product includes cryptographic software written by Eric Young
	56	* (eay@cryptsoft.com). This product includes software written by Tim
	57	* Hudson (tjh@cryptsoft.com).
	58	*
	59	*/
	60	/* ====================================================================
	61	* Copyright 2002 Sun Microsystems, Inc. ALL RIGHTS RESERVED.
	62	* Portions of this software developed by SUN MICROSYSTEMS, INC.,
	63	* and contributed to the OpenSSL project.
	64	*/
	65
	66	#include <openssl/err.h>
	67	#include <openssl/symhacks.h>
	68
	69	#include "ec_lcl.h"
	70
0f113f3e MC	71	int ec_GFp_simple_set_compressed_coordinates(const EC_GROUP *group,
	72	EC_POINT *point,
	73	const BIGNUM *x_, int y_bit,
	74	BN_CTX *ctx)
	75	{
	76	BN_CTX *new_ctx = NULL;
	77	BIGNUM tmp1, tmp2, x, y;
	78	int ret = 0;
	79
	80	/* clear error queue */
	81	ERR_clear_error();
	82
	83	if (ctx == NULL) {
	84	ctx = new_ctx = BN_CTX_new();
	85	if (ctx == NULL)
	86	return 0;
	87	}
	88
	89	y_bit = (y_bit != 0);
	90
	91	BN_CTX_start(ctx);
	92	tmp1 = BN_CTX_get(ctx);
	93	tmp2 = BN_CTX_get(ctx);
	94	x = BN_CTX_get(ctx);
	95	y = BN_CTX_get(ctx);
	96	if (y == NULL)
	97	goto err;
	98
35a1cc90 MC	99	/*-
	100	* Recover y. We have a Weierstrass equation
	101	* y^2 = x^3 + a*x + b,
	102	* so y is one of the square roots of x^3 + a*x + b.
	103	*/
0f113f3e MC	104
	105	/* tmp1 := x^3 */
	106	if (!BN_nnmod(x, x_, group->field, ctx))
	107	goto err;
	108	if (group->meth->field_decode == 0) {
	109	/* field_{sqr,mul} work on standard representation */
	110	if (!group->meth->field_sqr(group, tmp2, x_, ctx))
	111	goto err;
	112	if (!group->meth->field_mul(group, tmp1, tmp2, x_, ctx))
	113	goto err;
	114	} else {
	115	if (!BN_mod_sqr(tmp2, x_, group->field, ctx))
	116	goto err;
	117	if (!BN_mod_mul(tmp1, tmp2, x_, group->field, ctx))
	118	goto err;
	119	}
	120
	121	/* tmp1 := tmp1 + ax /
	122	if (group->a_is_minus3) {
	123	if (!BN_mod_lshift1_quick(tmp2, x, group->field))
	124	goto err;
	125	if (!BN_mod_add_quick(tmp2, tmp2, x, group->field))
	126	goto err;
	127	if (!BN_mod_sub_quick(tmp1, tmp1, tmp2, group->field))
	128	goto err;
	129	} else {
	130	if (group->meth->field_decode) {
	131	if (!group->meth->field_decode(group, tmp2, group->a, ctx))
	132	goto err;
	133	if (!BN_mod_mul(tmp2, tmp2, x, group->field, ctx))
	134	goto err;
	135	} else {
	136	/* field_mul works on standard representation */
	137	if (!group->meth->field_mul(group, tmp2, group->a, x, ctx))
	138	goto err;
	139	}
	140
	141	if (!BN_mod_add_quick(tmp1, tmp1, tmp2, group->field))
	142	goto err;
	143	}
	144
	145	/* tmp1 := tmp1 + b */
	146	if (group->meth->field_decode) {
	147	if (!group->meth->field_decode(group, tmp2, group->b, ctx))
	148	goto err;
	149	if (!BN_mod_add_quick(tmp1, tmp1, tmp2, group->field))
	150	goto err;
	151	} else {
	152	if (!BN_mod_add_quick(tmp1, tmp1, group->b, group->field))
	153	goto err;
	154	}
	155
	156	if (!BN_mod_sqrt(y, tmp1, group->field, ctx)) {
	157	unsigned long err = ERR_peek_last_error();
	158
	159	if (ERR_GET_LIB(err) == ERR_LIB_BN
	160	&& ERR_GET_REASON(err) == BN_R_NOT_A_SQUARE) {
	161	ERR_clear_error();
	162	ECerr(EC_F_EC_GFP_SIMPLE_SET_COMPRESSED_COORDINATES,
	163	EC_R_INVALID_COMPRESSED_POINT);
	164	} else
	165	ECerr(EC_F_EC_GFP_SIMPLE_SET_COMPRESSED_COORDINATES,
	166	ERR_R_BN_LIB);
	167	goto err;
168	}
169
170	if (y_bit != BN_is_odd(y)) {
171	if (BN_is_zero(y)) {
172	int kron;
173
174	kron = BN_kronecker(x, group->field, ctx);
175	if (kron == -2)
176	goto err;
177
178	if (kron == 1)
179	ECerr(EC_F_EC_GFP_SIMPLE_SET_COMPRESSED_COORDINATES,
180	EC_R_INVALID_COMPRESSION_BIT);
181	else
182	/*
183	* BN_mod_sqrt() should have cought this error (not a square)
184	*/
185	ECerr(EC_F_EC_GFP_SIMPLE_SET_COMPRESSED_COORDINATES,
186	EC_R_INVALID_COMPRESSED_POINT);
187	goto err;
188	}
189	if (!BN_usub(y, group->field, y))
190	goto err;
191	}
192	if (y_bit != BN_is_odd(y)) {
193	ECerr(EC_F_EC_GFP_SIMPLE_SET_COMPRESSED_COORDINATES,
194	ERR_R_INTERNAL_ERROR);
195	goto err;
196	}
197
198	if (!EC_POINT_set_affine_coordinates_GFp(group, point, x, y, ctx))
199	goto err;
200
201	ret = 1;
84b08eee DSH	202
84b08eee DSH	203	err:
0f113f3e MC	204	BN_CTX_end(ctx);
	205	if (new_ctx != NULL)
	206	BN_CTX_free(new_ctx);
	207	return ret;
	208	}
	209
	210	size_t ec_GFp_simple_point2oct(const EC_GROUP group, const EC_POINT point,
	211	point_conversion_form_t form,
	212	unsigned char buf, size_t len, BN_CTX ctx)
	213	{
	214	size_t ret;
	215	BN_CTX *new_ctx = NULL;
	216	int used_ctx = 0;
	217	BIGNUM x, y;
	218	size_t field_len, i, skip;
	219
	220	if ((form != POINT_CONVERSION_COMPRESSED)
	221	&& (form != POINT_CONVERSION_UNCOMPRESSED)
	222	&& (form != POINT_CONVERSION_HYBRID)) {
	223	ECerr(EC_F_EC_GFP_SIMPLE_POINT2OCT, EC_R_INVALID_FORM);
	224	goto err;
	225	}
	226
	227	if (EC_POINT_is_at_infinity(group, point)) {
	228	/* encodes to a single 0 octet */
	229	if (buf != NULL) {
	230	if (len < 1) {
	231	ECerr(EC_F_EC_GFP_SIMPLE_POINT2OCT, EC_R_BUFFER_TOO_SMALL);
	232	return 0;
	233	}
	234	buf[0] = 0;
	235	}
	236	return 1;
	237	}
	238
	239	/* ret := required output buffer length */
	240	field_len = BN_num_bytes(group->field);
	241	ret =
	242	(form ==
	243	POINT_CONVERSION_COMPRESSED) ? 1 + field_len : 1 + 2 * field_len;
	244
	245	/* if 'buf' is NULL, just return required length */
	246	if (buf != NULL) {
	247	if (len < ret) {
	248	ECerr(EC_F_EC_GFP_SIMPLE_POINT2OCT, EC_R_BUFFER_TOO_SMALL);
	249	goto err;
	250	}
	251
	252	if (ctx == NULL) {
	253	ctx = new_ctx = BN_CTX_new();
	254	if (ctx == NULL)
	255	return 0;
	256	}
	257
	258	BN_CTX_start(ctx);
	259	used_ctx = 1;
	260	x = BN_CTX_get(ctx);
	261	y = BN_CTX_get(ctx);
	262	if (y == NULL)
	263	goto err;
	264
	265	if (!EC_POINT_get_affine_coordinates_GFp(group, point, x, y, ctx))
	266	goto err;
	267
268	if ((form == POINT_CONVERSION_COMPRESSED
269	\|\| form == POINT_CONVERSION_HYBRID) && BN_is_odd(y))
270	buf[0] = form + 1;
271	else
272	buf[0] = form;
273
274	i = 1;
275
276	skip = field_len - BN_num_bytes(x);
277	if (skip > field_len) {
278	ECerr(EC_F_EC_GFP_SIMPLE_POINT2OCT, ERR_R_INTERNAL_ERROR);
279	goto err;
280	}
281	while (skip > 0) {
282	buf[i++] = 0;
283	skip--;
284	}
285	skip = BN_bn2bin(x, buf + i);
286	i += skip;
287	if (i != 1 + field_len) {
288	ECerr(EC_F_EC_GFP_SIMPLE_POINT2OCT, ERR_R_INTERNAL_ERROR);
289	goto err;
290	}
291
292	if (form == POINT_CONVERSION_UNCOMPRESSED
293	\|\| form == POINT_CONVERSION_HYBRID) {
294	skip = field_len - BN_num_bytes(y);
295	if (skip > field_len) {
296	ECerr(EC_F_EC_GFP_SIMPLE_POINT2OCT, ERR_R_INTERNAL_ERROR);
297	goto err;
298	}
299	while (skip > 0) {
300	buf[i++] = 0;
301	skip--;
302	}
303	skip = BN_bn2bin(y, buf + i);
304	i += skip;
305	}
306
307	if (i != ret) {
308	ECerr(EC_F_EC_GFP_SIMPLE_POINT2OCT, ERR_R_INTERNAL_ERROR);
309	goto err;
310	}
311	}
312
313	if (used_ctx)
314	BN_CTX_end(ctx);
315	if (new_ctx != NULL)
316	BN_CTX_free(new_ctx);
317	return ret;
84b08eee DSH	318
84b08eee DSH	319	err:
0f113f3e MC	320	if (used_ctx)
	321	BN_CTX_end(ctx);
	322	if (new_ctx != NULL)
	323	BN_CTX_free(new_ctx);
	324	return 0;
	325	}
84b08eee DSH	326
84b08eee DSH	327	int ec_GFp_simple_oct2point(const EC_GROUP group, EC_POINT point,
0f113f3e MC	328	const unsigned char buf, size_t len, BN_CTX ctx)
	329	{
	330	point_conversion_form_t form;
	331	int y_bit;
	332	BN_CTX *new_ctx = NULL;
	333	BIGNUM x, y;
	334	size_t field_len, enc_len;
	335	int ret = 0;
	336
	337	if (len == 0) {
	338	ECerr(EC_F_EC_GFP_SIMPLE_OCT2POINT, EC_R_BUFFER_TOO_SMALL);
	339	return 0;
	340	}
	341	form = buf[0];
	342	y_bit = form & 1;
	343	form = form & ~1U;
	344	if ((form != 0) && (form != POINT_CONVERSION_COMPRESSED)
	345	&& (form != POINT_CONVERSION_UNCOMPRESSED)
	346	&& (form != POINT_CONVERSION_HYBRID)) {
	347	ECerr(EC_F_EC_GFP_SIMPLE_OCT2POINT, EC_R_INVALID_ENCODING);
	348	return 0;
	349	}
	350	if ((form == 0 \|\| form == POINT_CONVERSION_UNCOMPRESSED) && y_bit) {
	351	ECerr(EC_F_EC_GFP_SIMPLE_OCT2POINT, EC_R_INVALID_ENCODING);
	352	return 0;
	353	}
	354
	355	if (form == 0) {
	356	if (len != 1) {
	357	ECerr(EC_F_EC_GFP_SIMPLE_OCT2POINT, EC_R_INVALID_ENCODING);
	358	return 0;
	359	}
	360
	361	return EC_POINT_set_to_infinity(group, point);
	362	}
	363
	364	field_len = BN_num_bytes(group->field);
	365	enc_len =
	366	(form ==
	367	POINT_CONVERSION_COMPRESSED) ? 1 + field_len : 1 + 2 * field_len;
	368
	369	if (len != enc_len) {
	370	ECerr(EC_F_EC_GFP_SIMPLE_OCT2POINT, EC_R_INVALID_ENCODING);
	371	return 0;
	372	}
	373
	374	if (ctx == NULL) {
	375	ctx = new_ctx = BN_CTX_new();
	376	if (ctx == NULL)
	377	return 0;
	378	}
	379
	380	BN_CTX_start(ctx);
	381	x = BN_CTX_get(ctx);
	382	y = BN_CTX_get(ctx);
	383	if (y == NULL)
	384	goto err;
	385
	386	if (!BN_bin2bn(buf + 1, field_len, x))
	387	goto err;
	388	if (BN_ucmp(x, group->field) >= 0) {
	389	ECerr(EC_F_EC_GFP_SIMPLE_OCT2POINT, EC_R_INVALID_ENCODING);
	390	goto err;
	391	}
392
393	if (form == POINT_CONVERSION_COMPRESSED) {
394	if (!EC_POINT_set_compressed_coordinates_GFp
395	(group, point, x, y_bit, ctx))
396	goto err;
397	} else {
398	if (!BN_bin2bn(buf + 1 + field_len, field_len, y))
399	goto err;
400	if (BN_ucmp(y, group->field) >= 0) {
401	ECerr(EC_F_EC_GFP_SIMPLE_OCT2POINT, EC_R_INVALID_ENCODING);
402	goto err;
403	}
404	if (form == POINT_CONVERSION_HYBRID) {
405	if (y_bit != BN_is_odd(y)) {
406	ECerr(EC_F_EC_GFP_SIMPLE_OCT2POINT, EC_R_INVALID_ENCODING);
407	goto err;
408	}
409	}
410
411	if (!EC_POINT_set_affine_coordinates_GFp(group, point, x, y, ctx))
412	goto err;
413	}
414
415	/* test required by X9.62 */
416	if (!EC_POINT_is_on_curve(group, point, ctx)) {
417	ECerr(EC_F_EC_GFP_SIMPLE_OCT2POINT, EC_R_POINT_IS_NOT_ON_CURVE);
418	goto err;
419	}
420
421	ret = 1;
84b08eee	422
0f113f3e MC	423	err:
	424	BN_CTX_end(ctx);
	425	if (new_ctx != NULL)
	426	BN_CTX_free(new_ctx);
	427	return ret;
	428	}