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openssl/crypto/ec/ec_lib.c

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v1.1.1t
2023-05-09 22:08:48 +00:00
/*
* Copyright 2001-2020 The OpenSSL Project Authors. All Rights Reserved.
* Copyright (c) 2002, Oracle and/or its affiliates. All rights reserved
*
* Licensed under the OpenSSL license (the "License"). You may not use
* this file except in compliance with the License. You can obtain a copy
* in the file LICENSE in the source distribution or at
* https://www.openssl.org/source/license.html
*/
#include <string.h>
#include <openssl/err.h>
#include <openssl/opensslv.h>
#include "ec_local.h"
/* functions for EC_GROUP objects */
EC_GROUP *EC_GROUP_new(const EC_METHOD *meth)
{
EC_GROUP *ret;
if (meth == NULL) {
ECerr(EC_F_EC_GROUP_NEW, EC_R_SLOT_FULL);
return NULL;
}
if (meth->group_init == 0) {
ECerr(EC_F_EC_GROUP_NEW, ERR_R_SHOULD_NOT_HAVE_BEEN_CALLED);
return NULL;
}
ret = OPENSSL_zalloc(sizeof(*ret));
if (ret == NULL) {
ECerr(EC_F_EC_GROUP_NEW, ERR_R_MALLOC_FAILURE);
return NULL;
}
ret->meth = meth;
if ((ret->meth->flags & EC_FLAGS_CUSTOM_CURVE) == 0) {
ret->order = BN_new();
if (ret->order == NULL)
goto err;
ret->cofactor = BN_new();
if (ret->cofactor == NULL)
goto err;
}
ret->asn1_flag = OPENSSL_EC_NAMED_CURVE;
ret->asn1_form = POINT_CONVERSION_UNCOMPRESSED;
if (!meth->group_init(ret))
goto err;
return ret;
err:
BN_free(ret->order);
BN_free(ret->cofactor);
OPENSSL_free(ret);
return NULL;
}
void EC_pre_comp_free(EC_GROUP *group)
{
switch (group->pre_comp_type) {
case PCT_none:
break;
case PCT_nistz256:
#ifdef ECP_NISTZ256_ASM
EC_nistz256_pre_comp_free(group->pre_comp.nistz256);
#endif
break;
#ifndef OPENSSL_NO_EC_NISTP_64_GCC_128
case PCT_nistp224:
EC_nistp224_pre_comp_free(group->pre_comp.nistp224);
break;
case PCT_nistp256:
EC_nistp256_pre_comp_free(group->pre_comp.nistp256);
break;
case PCT_nistp521:
EC_nistp521_pre_comp_free(group->pre_comp.nistp521);
break;
#else
case PCT_nistp224:
case PCT_nistp256:
case PCT_nistp521:
break;
#endif
case PCT_ec:
EC_ec_pre_comp_free(group->pre_comp.ec);
break;
}
group->pre_comp.ec = NULL;
}
void EC_GROUP_free(EC_GROUP *group)
{
if (!group)
return;
if (group->meth->group_finish != 0)
group->meth->group_finish(group);
EC_pre_comp_free(group);
BN_MONT_CTX_free(group->mont_data);
EC_POINT_free(group->generator);
BN_free(group->order);
BN_free(group->cofactor);
OPENSSL_free(group->seed);
OPENSSL_free(group);
}
void EC_GROUP_clear_free(EC_GROUP *group)
{
if (!group)
return;
if (group->meth->group_clear_finish != 0)
group->meth->group_clear_finish(group);
else if (group->meth->group_finish != 0)
group->meth->group_finish(group);
EC_pre_comp_free(group);
BN_MONT_CTX_free(group->mont_data);
EC_POINT_clear_free(group->generator);
BN_clear_free(group->order);
BN_clear_free(group->cofactor);
OPENSSL_clear_free(group->seed, group->seed_len);
OPENSSL_clear_free(group, sizeof(*group));
}
int EC_GROUP_copy(EC_GROUP *dest, const EC_GROUP *src)
{
if (dest->meth->group_copy == 0) {
ECerr(EC_F_EC_GROUP_COPY, ERR_R_SHOULD_NOT_HAVE_BEEN_CALLED);
return 0;
}
if (dest->meth != src->meth) {
ECerr(EC_F_EC_GROUP_COPY, EC_R_INCOMPATIBLE_OBJECTS);
return 0;
}
if (dest == src)
return 1;
dest->curve_name = src->curve_name;
/* Copy precomputed */
dest->pre_comp_type = src->pre_comp_type;
switch (src->pre_comp_type) {
case PCT_none:
dest->pre_comp.ec = NULL;
break;
case PCT_nistz256:
#ifdef ECP_NISTZ256_ASM
dest->pre_comp.nistz256 = EC_nistz256_pre_comp_dup(src->pre_comp.nistz256);
#endif
break;
#ifndef OPENSSL_NO_EC_NISTP_64_GCC_128
case PCT_nistp224:
dest->pre_comp.nistp224 = EC_nistp224_pre_comp_dup(src->pre_comp.nistp224);
break;
case PCT_nistp256:
dest->pre_comp.nistp256 = EC_nistp256_pre_comp_dup(src->pre_comp.nistp256);
break;
case PCT_nistp521:
dest->pre_comp.nistp521 = EC_nistp521_pre_comp_dup(src->pre_comp.nistp521);
break;
#else
case PCT_nistp224:
case PCT_nistp256:
case PCT_nistp521:
break;
#endif
case PCT_ec:
dest->pre_comp.ec = EC_ec_pre_comp_dup(src->pre_comp.ec);
break;
}
if (src->mont_data != NULL) {
if (dest->mont_data == NULL) {
dest->mont_data = BN_MONT_CTX_new();
if (dest->mont_data == NULL)
return 0;
}
if (!BN_MONT_CTX_copy(dest->mont_data, src->mont_data))
return 0;
} else {
/* src->generator == NULL */
BN_MONT_CTX_free(dest->mont_data);
dest->mont_data = NULL;
}
if (src->generator != NULL) {
if (dest->generator == NULL) {
dest->generator = EC_POINT_new(dest);
if (dest->generator == NULL)
return 0;
}
if (!EC_POINT_copy(dest->generator, src->generator))
return 0;
} else {
/* src->generator == NULL */
EC_POINT_clear_free(dest->generator);
dest->generator = NULL;
}
if ((src->meth->flags & EC_FLAGS_CUSTOM_CURVE) == 0) {
if (!BN_copy(dest->order, src->order))
return 0;
if (!BN_copy(dest->cofactor, src->cofactor))
return 0;
}
dest->asn1_flag = src->asn1_flag;
dest->asn1_form = src->asn1_form;
dest->decoded_from_explicit_params = src->decoded_from_explicit_params;
if (src->seed) {
OPENSSL_free(dest->seed);
if ((dest->seed = OPENSSL_malloc(src->seed_len)) == NULL) {
ECerr(EC_F_EC_GROUP_COPY, ERR_R_MALLOC_FAILURE);
return 0;
}
if (!memcpy(dest->seed, src->seed, src->seed_len))
return 0;
dest->seed_len = src->seed_len;
} else {
OPENSSL_free(dest->seed);
dest->seed = NULL;
dest->seed_len = 0;
}
return dest->meth->group_copy(dest, src);
}
EC_GROUP *EC_GROUP_dup(const EC_GROUP *a)
{
EC_GROUP *t = NULL;
int ok = 0;
if (a == NULL)
return NULL;
if ((t = EC_GROUP_new(a->meth)) == NULL)
return NULL;
if (!EC_GROUP_copy(t, a))
goto err;
ok = 1;
err:
if (!ok) {
EC_GROUP_free(t);
return NULL;
}
return t;
}
const EC_METHOD *EC_GROUP_method_of(const EC_GROUP *group)
{
return group->meth;
}
int EC_METHOD_get_field_type(const EC_METHOD *meth)
{
return meth->field_type;
}
static int ec_precompute_mont_data(EC_GROUP *);
/*-
* Try computing cofactor from the generator order (n) and field cardinality (q).
* This works for all curves of cryptographic interest.
*
* Hasse thm: q + 1 - 2*sqrt(q) <= n*h <= q + 1 + 2*sqrt(q)
* h_min = (q + 1 - 2*sqrt(q))/n
* h_max = (q + 1 + 2*sqrt(q))/n
* h_max - h_min = 4*sqrt(q)/n
* So if n > 4*sqrt(q) holds, there is only one possible value for h:
* h = \lfloor (h_min + h_max)/2 \rceil = \lfloor (q + 1)/n \rceil
*
* Otherwise, zero cofactor and return success.
*/
static int ec_guess_cofactor(EC_GROUP *group) {
int ret = 0;
BN_CTX *ctx = NULL;
BIGNUM *q = NULL;
/*-
* If the cofactor is too large, we cannot guess it.
* The RHS of below is a strict overestimate of lg(4 * sqrt(q))
*/
if (BN_num_bits(group->order) <= (BN_num_bits(group->field) + 1) / 2 + 3) {
/* default to 0 */
BN_zero(group->cofactor);
/* return success */
return 1;
}
if ((ctx = BN_CTX_new()) == NULL)
return 0;
BN_CTX_start(ctx);
if ((q = BN_CTX_get(ctx)) == NULL)
goto err;
/* set q = 2**m for binary fields; q = p otherwise */
if (group->meth->field_type == NID_X9_62_characteristic_two_field) {
BN_zero(q);
if (!BN_set_bit(q, BN_num_bits(group->field) - 1))
goto err;
} else {
if (!BN_copy(q, group->field))
goto err;
}
/* compute h = \lfloor (q + 1)/n \rceil = \lfloor (q + 1 + n/2)/n \rfloor */
if (!BN_rshift1(group->cofactor, group->order) /* n/2 */
|| !BN_add(group->cofactor, group->cofactor, q) /* q + n/2 */
/* q + 1 + n/2 */
|| !BN_add(group->cofactor, group->cofactor, BN_value_one())
/* (q + 1 + n/2)/n */
|| !BN_div(group->cofactor, NULL, group->cofactor, group->order, ctx))
goto err;
ret = 1;
err:
BN_CTX_end(ctx);
BN_CTX_free(ctx);
return ret;
}
int EC_GROUP_set_generator(EC_GROUP *group, const EC_POINT *generator,
const BIGNUM *order, const BIGNUM *cofactor)
{
if (generator == NULL) {
ECerr(EC_F_EC_GROUP_SET_GENERATOR, ERR_R_PASSED_NULL_PARAMETER);
return 0;
}
/* require group->field >= 1 */
if (group->field == NULL || BN_is_zero(group->field)
|| BN_is_negative(group->field)) {
ECerr(EC_F_EC_GROUP_SET_GENERATOR, EC_R_INVALID_FIELD);
return 0;
}
/*-
* - require order >= 1
* - enforce upper bound due to Hasse thm: order can be no more than one bit
* longer than field cardinality
*/
if (order == NULL || BN_is_zero(order) || BN_is_negative(order)
|| BN_num_bits(order) > BN_num_bits(group->field) + 1) {
ECerr(EC_F_EC_GROUP_SET_GENERATOR, EC_R_INVALID_GROUP_ORDER);
return 0;
}
/*-
* Unfortunately the cofactor is an optional field in many standards.
* Internally, the lib uses 0 cofactor as a marker for "unknown cofactor".
* So accept cofactor == NULL or cofactor >= 0.
*/
if (cofactor != NULL && BN_is_negative(cofactor)) {
ECerr(EC_F_EC_GROUP_SET_GENERATOR, EC_R_UNKNOWN_COFACTOR);
return 0;
}
if (group->generator == NULL) {
group->generator = EC_POINT_new(group);
if (group->generator == NULL)
return 0;
}
if (!EC_POINT_copy(group->generator, generator))
return 0;
if (!BN_copy(group->order, order))
return 0;
/* Either take the provided positive cofactor, or try to compute it */
if (cofactor != NULL && !BN_is_zero(cofactor)) {
if (!BN_copy(group->cofactor, cofactor))
return 0;
} else if (!ec_guess_cofactor(group)) {
BN_zero(group->cofactor);
return 0;
}
/*
* Some groups have an order with
* factors of two, which makes the Montgomery setup fail.
* |group->mont_data| will be NULL in this case.
*/
if (BN_is_odd(group->order)) {
return ec_precompute_mont_data(group);
}
BN_MONT_CTX_free(group->mont_data);
group->mont_data = NULL;
return 1;
}
const EC_POINT *EC_GROUP_get0_generator(const EC_GROUP *group)
{
return group->generator;
}
BN_MONT_CTX *EC_GROUP_get_mont_data(const EC_GROUP *group)
{
return group->mont_data;
}
int EC_GROUP_get_order(const EC_GROUP *group, BIGNUM *order, BN_CTX *ctx)
{
if (group->order == NULL)
return 0;
if (!BN_copy(order, group->order))
return 0;
return !BN_is_zero(order);
}
const BIGNUM *EC_GROUP_get0_order(const EC_GROUP *group)
{
return group->order;
}
int EC_GROUP_order_bits(const EC_GROUP *group)
{
return group->meth->group_order_bits(group);
}
int EC_GROUP_get_cofactor(const EC_GROUP *group, BIGNUM *cofactor,
BN_CTX *ctx)
{
if (group->cofactor == NULL)
return 0;
if (!BN_copy(cofactor, group->cofactor))
return 0;
return !BN_is_zero(group->cofactor);
}
const BIGNUM *EC_GROUP_get0_cofactor(const EC_GROUP *group)
{
return group->cofactor;
}
void EC_GROUP_set_curve_name(EC_GROUP *group, int nid)
{
group->curve_name = nid;
}
int EC_GROUP_get_curve_name(const EC_GROUP *group)
{
return group->curve_name;
}
void EC_GROUP_set_asn1_flag(EC_GROUP *group, int flag)
{
group->asn1_flag = flag;
}
int EC_GROUP_get_asn1_flag(const EC_GROUP *group)
{
return group->asn1_flag;
}
void EC_GROUP_set_point_conversion_form(EC_GROUP *group,
point_conversion_form_t form)
{
group->asn1_form = form;
}
point_conversion_form_t EC_GROUP_get_point_conversion_form(const EC_GROUP
*group)
{
return group->asn1_form;
}
size_t EC_GROUP_set_seed(EC_GROUP *group, const unsigned char *p, size_t len)
{
OPENSSL_free(group->seed);
group->seed = NULL;
group->seed_len = 0;
if (!len || !p)
return 1;
if ((group->seed = OPENSSL_malloc(len)) == NULL) {
ECerr(EC_F_EC_GROUP_SET_SEED, ERR_R_MALLOC_FAILURE);
return 0;
}
memcpy(group->seed, p, len);
group->seed_len = len;
return len;
}
unsigned char *EC_GROUP_get0_seed(const EC_GROUP *group)
{
return group->seed;
}
size_t EC_GROUP_get_seed_len(const EC_GROUP *group)
{
return group->seed_len;
}
int EC_GROUP_set_curve(EC_GROUP *group, const BIGNUM *p, const BIGNUM *a,
const BIGNUM *b, BN_CTX *ctx)
{
if (group->meth->group_set_curve == 0) {
ECerr(EC_F_EC_GROUP_SET_CURVE, ERR_R_SHOULD_NOT_HAVE_BEEN_CALLED);
return 0;
}
return group->meth->group_set_curve(group, p, a, b, ctx);
}
int EC_GROUP_get_curve(const EC_GROUP *group, BIGNUM *p, BIGNUM *a, BIGNUM *b,
BN_CTX *ctx)
{
if (group->meth->group_get_curve == NULL) {
ECerr(EC_F_EC_GROUP_GET_CURVE, ERR_R_SHOULD_NOT_HAVE_BEEN_CALLED);
return 0;
}
return group->meth->group_get_curve(group, p, a, b, ctx);
}
#if OPENSSL_API_COMPAT < 0x10200000L
int EC_GROUP_set_curve_GFp(EC_GROUP *group, const BIGNUM *p, const BIGNUM *a,
const BIGNUM *b, BN_CTX *ctx)
{
return EC_GROUP_set_curve(group, p, a, b, ctx);
}
int EC_GROUP_get_curve_GFp(const EC_GROUP *group, BIGNUM *p, BIGNUM *a,
BIGNUM *b, BN_CTX *ctx)
{
return EC_GROUP_get_curve(group, p, a, b, ctx);
}
# ifndef OPENSSL_NO_EC2M
int EC_GROUP_set_curve_GF2m(EC_GROUP *group, const BIGNUM *p, const BIGNUM *a,
const BIGNUM *b, BN_CTX *ctx)
{
return EC_GROUP_set_curve(group, p, a, b, ctx);
}
int EC_GROUP_get_curve_GF2m(const EC_GROUP *group, BIGNUM *p, BIGNUM *a,
BIGNUM *b, BN_CTX *ctx)
{
return EC_GROUP_get_curve(group, p, a, b, ctx);
}
# endif
#endif
int EC_GROUP_get_degree(const EC_GROUP *group)
{
if (group->meth->group_get_degree == 0) {
ECerr(EC_F_EC_GROUP_GET_DEGREE, ERR_R_SHOULD_NOT_HAVE_BEEN_CALLED);
return 0;
}
return group->meth->group_get_degree(group);
}
int EC_GROUP_check_discriminant(const EC_GROUP *group, BN_CTX *ctx)
{
if (group->meth->group_check_discriminant == 0) {
ECerr(EC_F_EC_GROUP_CHECK_DISCRIMINANT,
ERR_R_SHOULD_NOT_HAVE_BEEN_CALLED);
return 0;
}
return group->meth->group_check_discriminant(group, ctx);
}
int EC_GROUP_cmp(const EC_GROUP *a, const EC_GROUP *b, BN_CTX *ctx)
{
int r = 0;
BIGNUM *a1, *a2, *a3, *b1, *b2, *b3;
BN_CTX *ctx_new = NULL;
/* compare the field types */
if (EC_METHOD_get_field_type(EC_GROUP_method_of(a)) !=
EC_METHOD_get_field_type(EC_GROUP_method_of(b)))
return 1;
/* compare the curve name (if present in both) */
if (EC_GROUP_get_curve_name(a) && EC_GROUP_get_curve_name(b) &&
EC_GROUP_get_curve_name(a) != EC_GROUP_get_curve_name(b))
return 1;
if (a->meth->flags & EC_FLAGS_CUSTOM_CURVE)
return 0;
if (ctx == NULL)
ctx_new = ctx = BN_CTX_new();
if (ctx == NULL)
return -1;
BN_CTX_start(ctx);
a1 = BN_CTX_get(ctx);
a2 = BN_CTX_get(ctx);
a3 = BN_CTX_get(ctx);
b1 = BN_CTX_get(ctx);
b2 = BN_CTX_get(ctx);
b3 = BN_CTX_get(ctx);
if (b3 == NULL) {
BN_CTX_end(ctx);
BN_CTX_free(ctx_new);
return -1;
}
/*
* XXX This approach assumes that the external representation of curves
* over the same field type is the same.
*/
if (!a->meth->group_get_curve(a, a1, a2, a3, ctx) ||
!b->meth->group_get_curve(b, b1, b2, b3, ctx))
r = 1;
if (r || BN_cmp(a1, b1) || BN_cmp(a2, b2) || BN_cmp(a3, b3))
r = 1;
/* XXX EC_POINT_cmp() assumes that the methods are equal */
if (r || EC_POINT_cmp(a, EC_GROUP_get0_generator(a),
EC_GROUP_get0_generator(b), ctx))
r = 1;
if (!r) {
const BIGNUM *ao, *bo, *ac, *bc;
/* compare the order and cofactor */
ao = EC_GROUP_get0_order(a);
bo = EC_GROUP_get0_order(b);
ac = EC_GROUP_get0_cofactor(a);
bc = EC_GROUP_get0_cofactor(b);
if (ao == NULL || bo == NULL) {
BN_CTX_end(ctx);
BN_CTX_free(ctx_new);
return -1;
}
if (BN_cmp(ao, bo) || BN_cmp(ac, bc))
r = 1;
}
BN_CTX_end(ctx);
BN_CTX_free(ctx_new);
return r;
}
/* functions for EC_POINT objects */
EC_POINT *EC_POINT_new(const EC_GROUP *group)
{
EC_POINT *ret;
if (group == NULL) {
ECerr(EC_F_EC_POINT_NEW, ERR_R_PASSED_NULL_PARAMETER);
return NULL;
}
if (group->meth->point_init == NULL) {
ECerr(EC_F_EC_POINT_NEW, ERR_R_SHOULD_NOT_HAVE_BEEN_CALLED);
return NULL;
}
ret = OPENSSL_zalloc(sizeof(*ret));
if (ret == NULL) {
ECerr(EC_F_EC_POINT_NEW, ERR_R_MALLOC_FAILURE);
return NULL;
}
ret->meth = group->meth;
ret->curve_name = group->curve_name;
if (!ret->meth->point_init(ret)) {
OPENSSL_free(ret);
return NULL;
}
return ret;
}
void EC_POINT_free(EC_POINT *point)
{
if (!point)
return;
if (point->meth->point_finish != 0)
point->meth->point_finish(point);
OPENSSL_free(point);
}
void EC_POINT_clear_free(EC_POINT *point)
{
if (!point)
return;
if (point->meth->point_clear_finish != 0)
point->meth->point_clear_finish(point);
else if (point->meth->point_finish != 0)
point->meth->point_finish(point);
OPENSSL_clear_free(point, sizeof(*point));
}
int EC_POINT_copy(EC_POINT *dest, const EC_POINT *src)
{
if (dest->meth->point_copy == 0) {
ECerr(EC_F_EC_POINT_COPY, ERR_R_SHOULD_NOT_HAVE_BEEN_CALLED);
return 0;
}
if (dest->meth != src->meth
|| (dest->curve_name != src->curve_name
&& dest->curve_name != 0
&& src->curve_name != 0)) {
ECerr(EC_F_EC_POINT_COPY, EC_R_INCOMPATIBLE_OBJECTS);
return 0;
}
if (dest == src)
return 1;
return dest->meth->point_copy(dest, src);
}
EC_POINT *EC_POINT_dup(const EC_POINT *a, const EC_GROUP *group)
{
EC_POINT *t;
int r;
if (a == NULL)
return NULL;
t = EC_POINT_new(group);
if (t == NULL)
return NULL;
r = EC_POINT_copy(t, a);
if (!r) {
EC_POINT_free(t);
return NULL;
}
return t;
}
const EC_METHOD *EC_POINT_method_of(const EC_POINT *point)
{
return point->meth;
}
int EC_POINT_set_to_infinity(const EC_GROUP *group, EC_POINT *point)
{
if (group->meth->point_set_to_infinity == 0) {
ECerr(EC_F_EC_POINT_SET_TO_INFINITY,
ERR_R_SHOULD_NOT_HAVE_BEEN_CALLED);
return 0;
}
if (group->meth != point->meth) {
ECerr(EC_F_EC_POINT_SET_TO_INFINITY, EC_R_INCOMPATIBLE_OBJECTS);
return 0;
}
return group->meth->point_set_to_infinity(group, point);
}
int EC_POINT_set_Jprojective_coordinates_GFp(const EC_GROUP *group,
EC_POINT *point, const BIGNUM *x,
const BIGNUM *y, const BIGNUM *z,
BN_CTX *ctx)
{
if (group->meth->point_set_Jprojective_coordinates_GFp == 0) {
ECerr(EC_F_EC_POINT_SET_JPROJECTIVE_COORDINATES_GFP,
ERR_R_SHOULD_NOT_HAVE_BEEN_CALLED);
return 0;
}
if (!ec_point_is_compat(point, group)) {
ECerr(EC_F_EC_POINT_SET_JPROJECTIVE_COORDINATES_GFP,
EC_R_INCOMPATIBLE_OBJECTS);
return 0;
}
return group->meth->point_set_Jprojective_coordinates_GFp(group, point, x,
y, z, ctx);
}
int EC_POINT_get_Jprojective_coordinates_GFp(const EC_GROUP *group,
const EC_POINT *point, BIGNUM *x,
BIGNUM *y, BIGNUM *z,
BN_CTX *ctx)
{
if (group->meth->point_get_Jprojective_coordinates_GFp == 0) {
ECerr(EC_F_EC_POINT_GET_JPROJECTIVE_COORDINATES_GFP,
ERR_R_SHOULD_NOT_HAVE_BEEN_CALLED);
return 0;
}
if (!ec_point_is_compat(point, group)) {
ECerr(EC_F_EC_POINT_GET_JPROJECTIVE_COORDINATES_GFP,
EC_R_INCOMPATIBLE_OBJECTS);
return 0;
}
return group->meth->point_get_Jprojective_coordinates_GFp(group, point, x,
y, z, ctx);
}
int EC_POINT_set_affine_coordinates(const EC_GROUP *group, EC_POINT *point,
const BIGNUM *x, const BIGNUM *y,
BN_CTX *ctx)
{
if (group->meth->point_set_affine_coordinates == NULL) {
ECerr(EC_F_EC_POINT_SET_AFFINE_COORDINATES,
ERR_R_SHOULD_NOT_HAVE_BEEN_CALLED);
return 0;
}
if (!ec_point_is_compat(point, group)) {
ECerr(EC_F_EC_POINT_SET_AFFINE_COORDINATES, EC_R_INCOMPATIBLE_OBJECTS);
return 0;
}
if (!group->meth->point_set_affine_coordinates(group, point, x, y, ctx))
return 0;
if (EC_POINT_is_on_curve(group, point, ctx) <= 0) {
ECerr(EC_F_EC_POINT_SET_AFFINE_COORDINATES, EC_R_POINT_IS_NOT_ON_CURVE);
return 0;
}
return 1;
}
#if OPENSSL_API_COMPAT < 0x10200000L
int EC_POINT_set_affine_coordinates_GFp(const EC_GROUP *group,
EC_POINT *point, const BIGNUM *x,
const BIGNUM *y, BN_CTX *ctx)
{
return EC_POINT_set_affine_coordinates(group, point, x, y, ctx);
}
# ifndef OPENSSL_NO_EC2M
int EC_POINT_set_affine_coordinates_GF2m(const EC_GROUP *group,
EC_POINT *point, const BIGNUM *x,
const BIGNUM *y, BN_CTX *ctx)
{
return EC_POINT_set_affine_coordinates(group, point, x, y, ctx);
}
# endif
#endif
int EC_POINT_get_affine_coordinates(const EC_GROUP *group,
const EC_POINT *point, BIGNUM *x, BIGNUM *y,
BN_CTX *ctx)
{
if (group->meth->point_get_affine_coordinates == NULL) {
ECerr(EC_F_EC_POINT_GET_AFFINE_COORDINATES,
ERR_R_SHOULD_NOT_HAVE_BEEN_CALLED);
return 0;
}
if (!ec_point_is_compat(point, group)) {
ECerr(EC_F_EC_POINT_GET_AFFINE_COORDINATES, EC_R_INCOMPATIBLE_OBJECTS);
return 0;
}
if (EC_POINT_is_at_infinity(group, point)) {
ECerr(EC_F_EC_POINT_GET_AFFINE_COORDINATES, EC_R_POINT_AT_INFINITY);
return 0;
}
return group->meth->point_get_affine_coordinates(group, point, x, y, ctx);
}
#if OPENSSL_API_COMPAT < 0x10200000L
int EC_POINT_get_affine_coordinates_GFp(const EC_GROUP *group,
const EC_POINT *point, BIGNUM *x,
BIGNUM *y, BN_CTX *ctx)
{
return EC_POINT_get_affine_coordinates(group, point, x, y, ctx);
}
# ifndef OPENSSL_NO_EC2M
int EC_POINT_get_affine_coordinates_GF2m(const EC_GROUP *group,
const EC_POINT *point, BIGNUM *x,
BIGNUM *y, BN_CTX *ctx)
{
return EC_POINT_get_affine_coordinates(group, point, x, y, ctx);
}
# endif
#endif
int EC_POINT_add(const EC_GROUP *group, EC_POINT *r, const EC_POINT *a,
const EC_POINT *b, BN_CTX *ctx)
{
if (group->meth->add == 0) {
ECerr(EC_F_EC_POINT_ADD, ERR_R_SHOULD_NOT_HAVE_BEEN_CALLED);
return 0;
}
if (!ec_point_is_compat(r, group) || !ec_point_is_compat(a, group)
|| !ec_point_is_compat(b, group)) {
ECerr(EC_F_EC_POINT_ADD, EC_R_INCOMPATIBLE_OBJECTS);
return 0;
}
return group->meth->add(group, r, a, b, ctx);
}
int EC_POINT_dbl(const EC_GROUP *group, EC_POINT *r, const EC_POINT *a,
BN_CTX *ctx)
{
if (group->meth->dbl == 0) {
ECerr(EC_F_EC_POINT_DBL, ERR_R_SHOULD_NOT_HAVE_BEEN_CALLED);
return 0;
}
if (!ec_point_is_compat(r, group) || !ec_point_is_compat(a, group)) {
ECerr(EC_F_EC_POINT_DBL, EC_R_INCOMPATIBLE_OBJECTS);
return 0;
}
return group->meth->dbl(group, r, a, ctx);
}
int EC_POINT_invert(const EC_GROUP *group, EC_POINT *a, BN_CTX *ctx)
{
if (group->meth->invert == 0) {
ECerr(EC_F_EC_POINT_INVERT, ERR_R_SHOULD_NOT_HAVE_BEEN_CALLED);
return 0;
}
if (!ec_point_is_compat(a, group)) {
ECerr(EC_F_EC_POINT_INVERT, EC_R_INCOMPATIBLE_OBJECTS);
return 0;
}
return group->meth->invert(group, a, ctx);
}
int EC_POINT_is_at_infinity(const EC_GROUP *group, const EC_POINT *point)
{
if (group->meth->is_at_infinity == 0) {
ECerr(EC_F_EC_POINT_IS_AT_INFINITY,
ERR_R_SHOULD_NOT_HAVE_BEEN_CALLED);
return 0;
}
if (!ec_point_is_compat(point, group)) {
ECerr(EC_F_EC_POINT_IS_AT_INFINITY, EC_R_INCOMPATIBLE_OBJECTS);
return 0;
}
return group->meth->is_at_infinity(group, point);
}
/*
* Check whether an EC_POINT is on the curve or not. Note that the return
* value for this function should NOT be treated as a boolean. Return values:
* 1: The point is on the curve
* 0: The point is not on the curve
* -1: An error occurred
*/
int EC_POINT_is_on_curve(const EC_GROUP *group, const EC_POINT *point,
BN_CTX *ctx)
{
if (group->meth->is_on_curve == 0) {
ECerr(EC_F_EC_POINT_IS_ON_CURVE, ERR_R_SHOULD_NOT_HAVE_BEEN_CALLED);
return 0;
}
if (!ec_point_is_compat(point, group)) {
ECerr(EC_F_EC_POINT_IS_ON_CURVE, EC_R_INCOMPATIBLE_OBJECTS);
return 0;
}
return group->meth->is_on_curve(group, point, ctx);
}
int EC_POINT_cmp(const EC_GROUP *group, const EC_POINT *a, const EC_POINT *b,
BN_CTX *ctx)
{
if (group->meth->point_cmp == 0) {
ECerr(EC_F_EC_POINT_CMP, ERR_R_SHOULD_NOT_HAVE_BEEN_CALLED);
return -1;
}
if (!ec_point_is_compat(a, group) || !ec_point_is_compat(b, group)) {
ECerr(EC_F_EC_POINT_CMP, EC_R_INCOMPATIBLE_OBJECTS);
return -1;
}
return group->meth->point_cmp(group, a, b, ctx);
}
int EC_POINT_make_affine(const EC_GROUP *group, EC_POINT *point, BN_CTX *ctx)
{
if (group->meth->make_affine == 0) {
ECerr(EC_F_EC_POINT_MAKE_AFFINE, ERR_R_SHOULD_NOT_HAVE_BEEN_CALLED);
return 0;
}
if (!ec_point_is_compat(point, group)) {
ECerr(EC_F_EC_POINT_MAKE_AFFINE, EC_R_INCOMPATIBLE_OBJECTS);
return 0;
}
return group->meth->make_affine(group, point, ctx);
}
int EC_POINTs_make_affine(const EC_GROUP *group, size_t num,
EC_POINT *points[], BN_CTX *ctx)
{
size_t i;
if (group->meth->points_make_affine == 0) {
ECerr(EC_F_EC_POINTS_MAKE_AFFINE, ERR_R_SHOULD_NOT_HAVE_BEEN_CALLED);
return 0;
}
for (i = 0; i < num; i++) {
if (!ec_point_is_compat(points[i], group)) {
ECerr(EC_F_EC_POINTS_MAKE_AFFINE, EC_R_INCOMPATIBLE_OBJECTS);
return 0;
}
}
return group->meth->points_make_affine(group, num, points, ctx);
}
/*
* Functions for point multiplication. If group->meth->mul is 0, we use the
* wNAF-based implementations in ec_mult.c; otherwise we dispatch through
* methods.
*/
int EC_POINTs_mul(const EC_GROUP *group, EC_POINT *r, const BIGNUM *scalar,
size_t num, const EC_POINT *points[],
const BIGNUM *scalars[], BN_CTX *ctx)
{
int ret = 0;
size_t i = 0;
BN_CTX *new_ctx = NULL;
if (!ec_point_is_compat(r, group)) {
ECerr(EC_F_EC_POINTS_MUL, EC_R_INCOMPATIBLE_OBJECTS);
return 0;
}
if (scalar == NULL && num == 0)
return EC_POINT_set_to_infinity(group, r);
for (i = 0; i < num; i++) {
if (!ec_point_is_compat(points[i], group)) {
ECerr(EC_F_EC_POINTS_MUL, EC_R_INCOMPATIBLE_OBJECTS);
return 0;
}
}
if (ctx == NULL && (ctx = new_ctx = BN_CTX_secure_new()) == NULL) {
ECerr(EC_F_EC_POINTS_MUL, ERR_R_INTERNAL_ERROR);
return 0;
}
if (group->meth->mul != NULL)
ret = group->meth->mul(group, r, scalar, num, points, scalars, ctx);
else
/* use default */
ret = ec_wNAF_mul(group, r, scalar, num, points, scalars, ctx);
BN_CTX_free(new_ctx);
return ret;
}
int EC_POINT_mul(const EC_GROUP *group, EC_POINT *r, const BIGNUM *g_scalar,
const EC_POINT *point, const BIGNUM *p_scalar, BN_CTX *ctx)
{
/* just a convenient interface to EC_POINTs_mul() */
const EC_POINT *points[1];
const BIGNUM *scalars[1];
points[0] = point;
scalars[0] = p_scalar;
return EC_POINTs_mul(group, r, g_scalar,
(point != NULL
&& p_scalar != NULL), points, scalars, ctx);
}
int EC_GROUP_precompute_mult(EC_GROUP *group, BN_CTX *ctx)
{
if (group->meth->mul == 0)
/* use default */
return ec_wNAF_precompute_mult(group, ctx);
if (group->meth->precompute_mult != 0)
return group->meth->precompute_mult(group, ctx);
else
return 1; /* nothing to do, so report success */
}
int EC_GROUP_have_precompute_mult(const EC_GROUP *group)
{
if (group->meth->mul == 0)
/* use default */
return ec_wNAF_have_precompute_mult(group);
if (group->meth->have_precompute_mult != 0)
return group->meth->have_precompute_mult(group);
else
return 0; /* cannot tell whether precomputation has
* been performed */
}
/*
* ec_precompute_mont_data sets |group->mont_data| from |group->order| and
* returns one on success. On error it returns zero.
*/
static int ec_precompute_mont_data(EC_GROUP *group)
{
BN_CTX *ctx = BN_CTX_new();
int ret = 0;
BN_MONT_CTX_free(group->mont_data);
group->mont_data = NULL;
if (ctx == NULL)
goto err;
group->mont_data = BN_MONT_CTX_new();
if (group->mont_data == NULL)
goto err;
if (!BN_MONT_CTX_set(group->mont_data, group->order, ctx)) {
BN_MONT_CTX_free(group->mont_data);
group->mont_data = NULL;
goto err;
}
ret = 1;
err:
BN_CTX_free(ctx);
return ret;
}
int EC_KEY_set_ex_data(EC_KEY *key, int idx, void *arg)
{
return CRYPTO_set_ex_data(&key->ex_data, idx, arg);
}
void *EC_KEY_get_ex_data(const EC_KEY *key, int idx)
{
return CRYPTO_get_ex_data(&key->ex_data, idx);
}
int ec_group_simple_order_bits(const EC_GROUP *group)
{
if (group->order == NULL)
return 0;
return BN_num_bits(group->order);
}
static int ec_field_inverse_mod_ord(const EC_GROUP *group, BIGNUM *r,
const BIGNUM *x, BN_CTX *ctx)
{
BIGNUM *e = NULL;
BN_CTX *new_ctx = NULL;
int ret = 0;
if (group->mont_data == NULL)
return 0;
if (ctx == NULL && (ctx = new_ctx = BN_CTX_secure_new()) == NULL)
return 0;
BN_CTX_start(ctx);
if ((e = BN_CTX_get(ctx)) == NULL)
goto err;
/*-
* We want inverse in constant time, therefore we utilize the fact
* order must be prime and use Fermats Little Theorem instead.
*/
if (!BN_set_word(e, 2))
goto err;
if (!BN_sub(e, group->order, e))
goto err;
/*-
* Exponent e is public.
* No need for scatter-gather or BN_FLG_CONSTTIME.
*/
if (!BN_mod_exp_mont(r, x, e, group->order, ctx, group->mont_data))
goto err;
ret = 1;
err:
BN_CTX_end(ctx);
BN_CTX_free(new_ctx);
return ret;
}
/*-
* Default behavior, if group->meth->field_inverse_mod_ord is NULL:
* - When group->order is even, this function returns an error.
* - When group->order is otherwise composite, the correctness
* of the output is not guaranteed.
* - When x is outside the range [1, group->order), the correctness
* of the output is not guaranteed.
* - Otherwise, this function returns the multiplicative inverse in the
* range [1, group->order).
*
* EC_METHODs must implement their own field_inverse_mod_ord for
* other functionality.
*/
int ec_group_do_inverse_ord(const EC_GROUP *group, BIGNUM *res,
const BIGNUM *x, BN_CTX *ctx)
{
if (group->meth->field_inverse_mod_ord != NULL)
return group->meth->field_inverse_mod_ord(group, res, x, ctx);
else
return ec_field_inverse_mod_ord(group, res, x, ctx);
}
/*-
* Coordinate blinding for EC_POINT.
*
* The underlying EC_METHOD can optionally implement this function:
* underlying implementations should return 0 on errors, or 1 on
* success.
*
* This wrapper returns 1 in case the underlying EC_METHOD does not
* support coordinate blinding.
*/
int ec_point_blind_coordinates(const EC_GROUP *group, EC_POINT *p, BN_CTX *ctx)
{
if (group->meth->blind_coordinates == NULL)
return 1; /* ignore if not implemented */
return group->meth->blind_coordinates(group, p, ctx);
}