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openssl/crypto/ec/ec_key.c
Tomas Mraz 7ed6de997f Copyright year updates 
Reviewed-by: Neil Horman <nhorman@openssl.org>
Release: yes
2024-09-05 09:35:49 +02:00

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/*
* Copyright 2002-2024 The OpenSSL Project Authors. All Rights Reserved.
* Copyright (c) 2002, Oracle and/or its affiliates. All rights reserved
*
* Licensed under the Apache License 2.0 (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
*/
/*
* EC_KEY low level APIs are deprecated for public use, but still ok for
* internal use.
*/
#include "internal/deprecated.h"
#include "internal/cryptlib.h"
#include <string.h>
#include "ec_local.h"
#include "internal/refcount.h"
#include <openssl/err.h>
#ifndef FIPS_MODULE
# include <openssl/engine.h>
#endif
#include <openssl/self_test.h>
#include "prov/providercommon.h"
#include "prov/ecx.h"
#include "crypto/bn.h"
static int ecdsa_keygen_pairwise_test(EC_KEY *eckey, OSSL_CALLBACK *cb,
void *cbarg);
#ifndef FIPS_MODULE
EC_KEY *EC_KEY_new(void)
{
return ossl_ec_key_new_method_int(NULL, NULL, NULL);
}
#endif
EC_KEY *EC_KEY_new_ex(OSSL_LIB_CTX *ctx, const char *propq)
{
return ossl_ec_key_new_method_int(ctx, propq, NULL);
}
EC_KEY *EC_KEY_new_by_curve_name_ex(OSSL_LIB_CTX *ctx, const char *propq,
int nid)
{
EC_KEY *ret = EC_KEY_new_ex(ctx, propq);
if (ret == NULL)
return NULL;
ret->group = EC_GROUP_new_by_curve_name_ex(ctx, propq, nid);
if (ret->group == NULL) {
EC_KEY_free(ret);
return NULL;
}
if (ret->meth->set_group != NULL
&& ret->meth->set_group(ret, ret->group) == 0) {
EC_KEY_free(ret);
return NULL;
}
return ret;
}
#ifndef FIPS_MODULE
EC_KEY *EC_KEY_new_by_curve_name(int nid)
{
return EC_KEY_new_by_curve_name_ex(NULL, NULL, nid);
}
#endif
void EC_KEY_free(EC_KEY *r)
{
int i;
if (r == NULL)
return;
CRYPTO_DOWN_REF(&r->references, &i);
REF_PRINT_COUNT("EC_KEY", r);
if (i > 0)
return;
REF_ASSERT_ISNT(i < 0);
if (r->meth != NULL && r->meth->finish != NULL)
r->meth->finish(r);
#if !defined(OPENSSL_NO_ENGINE) && !defined(FIPS_MODULE)
ENGINE_finish(r->engine);
#endif
if (r->group && r->group->meth->keyfinish)
r->group->meth->keyfinish(r);
#ifndef FIPS_MODULE
CRYPTO_free_ex_data(CRYPTO_EX_INDEX_EC_KEY, r, &r->ex_data);
#endif
CRYPTO_FREE_REF(&r->references);
EC_GROUP_free(r->group);
EC_POINT_free(r->pub_key);
BN_clear_free(r->priv_key);
OPENSSL_free(r->propq);
OPENSSL_clear_free((void *)r, sizeof(EC_KEY));
}
EC_KEY *EC_KEY_copy(EC_KEY *dest, const EC_KEY *src)
{
if (dest == NULL || src == NULL) {
ERR_raise(ERR_LIB_EC, ERR_R_PASSED_NULL_PARAMETER);
return NULL;
}
if (src->meth != dest->meth) {
if (dest->meth->finish != NULL)
dest->meth->finish(dest);
if (dest->group && dest->group->meth->keyfinish)
dest->group->meth->keyfinish(dest);
#if !defined(OPENSSL_NO_ENGINE) && !defined(FIPS_MODULE)
if (ENGINE_finish(dest->engine) == 0)
return 0;
dest->engine = NULL;
#endif
}
dest->libctx = src->libctx;
/* copy the parameters */
if (src->group != NULL) {
/* clear the old group */
EC_GROUP_free(dest->group);
dest->group = ossl_ec_group_new_ex(src->libctx, src->propq,
src->group->meth);
if (dest->group == NULL)
return NULL;
if (!EC_GROUP_copy(dest->group, src->group))
return NULL;
/* copy the public key */
if (src->pub_key != NULL) {
EC_POINT_free(dest->pub_key);
dest->pub_key = EC_POINT_new(src->group);
if (dest->pub_key == NULL)
return NULL;
if (!EC_POINT_copy(dest->pub_key, src->pub_key))
return NULL;
}
/* copy the private key */
if (src->priv_key != NULL) {
if (dest->priv_key == NULL) {
dest->priv_key = BN_new();
if (dest->priv_key == NULL)
return NULL;
}
if (!BN_copy(dest->priv_key, src->priv_key))
return NULL;
if (src->group->meth->keycopy
&& src->group->meth->keycopy(dest, src) == 0)
return NULL;
}
}
/* copy the rest */
dest->enc_flag = src->enc_flag;
dest->conv_form = src->conv_form;
dest->version = src->version;
dest->flags = src->flags;
#ifndef FIPS_MODULE
if (!CRYPTO_dup_ex_data(CRYPTO_EX_INDEX_EC_KEY,
&dest->ex_data, &src->ex_data))
return NULL;
#endif
if (src->meth != dest->meth) {
#if !defined(OPENSSL_NO_ENGINE) && !defined(FIPS_MODULE)
if (src->engine != NULL && ENGINE_init(src->engine) == 0)
return NULL;
dest->engine = src->engine;
#endif
dest->meth = src->meth;
}
if (src->meth->copy != NULL && src->meth->copy(dest, src) == 0)
return NULL;
dest->dirty_cnt++;
return dest;
}
EC_KEY *EC_KEY_dup(const EC_KEY *ec_key)
{
return ossl_ec_key_dup(ec_key, OSSL_KEYMGMT_SELECT_ALL);
}
int EC_KEY_up_ref(EC_KEY *r)
{
int i;
if (CRYPTO_UP_REF(&r->references, &i) <= 0)
return 0;
REF_PRINT_COUNT("EC_KEY", r);
REF_ASSERT_ISNT(i < 2);
return ((i > 1) ? 1 : 0);
}
ENGINE *EC_KEY_get0_engine(const EC_KEY *eckey)
{
return eckey->engine;
}
int EC_KEY_generate_key(EC_KEY *eckey)
{
if (eckey == NULL || eckey->group == NULL) {
ERR_raise(ERR_LIB_EC, ERR_R_PASSED_NULL_PARAMETER);
return 0;
}
if (eckey->meth->keygen != NULL) {
int ret;
ret = eckey->meth->keygen(eckey);
if (ret == 1)
eckey->dirty_cnt++;
return ret;
}
ERR_raise(ERR_LIB_EC, EC_R_OPERATION_NOT_SUPPORTED);
return 0;
}
int ossl_ec_key_gen(EC_KEY *eckey)
{
int ret;
ret = eckey->group->meth->keygen(eckey);
if (ret == 1)
eckey->dirty_cnt++;
return ret;
}
/*
* Refer: FIPS 140-3 IG 10.3.A Additional Comment 1
* Perform a KAT by duplicating the public key generation.
*
* NOTE: This issue requires a background understanding, provided in a separate
* document; the current IG 10.3.A AC1 is insufficient regarding the PCT for
* the key agreement scenario.
*
* Currently IG 10.3.A requires PCT in the mode of use prior to use of the
* key pair, citing the PCT defined in the associated standard. For key
* agreement, the only PCT defined in SP 800-56A is that of Section 5.6.2.4:
* the comparison of the original public key to a newly calculated public key.
*/
static int ecdsa_keygen_knownanswer_test(EC_KEY *eckey, BN_CTX *ctx,
OSSL_CALLBACK *cb, void *cbarg)
{
int len, ret = 0;
OSSL_SELF_TEST *st = NULL;
unsigned char bytes[512] = {0};
EC_POINT *pub_key2 = EC_POINT_new(eckey->group);
if (pub_key2 == NULL)
return 0;
st = OSSL_SELF_TEST_new(cb, cbarg);
if (st == NULL)
return 0;
OSSL_SELF_TEST_onbegin(st, OSSL_SELF_TEST_TYPE_PCT_KAT,
OSSL_SELF_TEST_DESC_PCT_ECDSA);
/* pub_key = priv_key * G (where G is a point on the curve) */
if (!EC_POINT_mul(eckey->group, pub_key2, eckey->priv_key, NULL, NULL, ctx))
goto err;
if (BN_num_bytes(pub_key2->X) > (int)sizeof(bytes))
goto err;
len = BN_bn2bin(pub_key2->X, bytes);
if (OSSL_SELF_TEST_oncorrupt_byte(st, bytes)
&& BN_bin2bn(bytes, len, pub_key2->X) == NULL)
goto err;
ret = !EC_POINT_cmp(eckey->group, eckey->pub_key, pub_key2, ctx);
err:
OSSL_SELF_TEST_onend(st, ret);
OSSL_SELF_TEST_free(st);
EC_POINT_free(pub_key2);
return ret;
}
/*
* ECC Key generation.
* See SP800-56AR3 5.6.1.2.2 "Key Pair Generation by Testing Candidates"
*
* Params:
* libctx A context containing an optional self test callback.
* eckey An EC key object that contains domain params. The generated keypair
* is stored in this object.
* pairwise_test Set to non zero to perform a pairwise test. If the test
* fails then the keypair is not generated,
* Returns 1 if the keypair was generated or 0 otherwise.
*/
static int ec_generate_key(EC_KEY *eckey, int pairwise_test)
{
int ok = 0;
BIGNUM *priv_key = NULL;
const BIGNUM *tmp = NULL;
BIGNUM *order = NULL;
EC_POINT *pub_key = NULL;
const EC_GROUP *group = eckey->group;
BN_CTX *ctx = BN_CTX_secure_new_ex(eckey->libctx);
int sm2 = EC_KEY_get_flags(eckey) & EC_FLAG_SM2_RANGE ? 1 : 0;
if (ctx == NULL)
goto err;
if (eckey->priv_key == NULL) {
priv_key = BN_secure_new();
if (priv_key == NULL)
goto err;
} else
priv_key = eckey->priv_key;
/*
* Steps (1-2): Check domain parameters and security strength.
* These steps must be done by the user. This would need to be
* stated in the security policy.
*/
tmp = EC_GROUP_get0_order(group);
if (tmp == NULL)
goto err;
/*
* Steps (3-7): priv_key = DRBG_RAND(order_n_bits) (range [1, n-1]).
* Although this is slightly different from the standard, it is effectively
* equivalent as it gives an unbiased result ranging from 1..n-1. It is also
* faster as the standard needs to retry more often. Also doing
* 1 + rand[0..n-2] would effect the way that tests feed dummy entropy into
* rand so the simpler backward compatible method has been used here.
*/
/* range of SM2 private key is [1, n-1) */
if (sm2) {
order = BN_new();
if (order == NULL || !BN_sub(order, tmp, BN_value_one()))
goto err;
} else {
order = BN_dup(tmp);
if (order == NULL)
goto err;
}
do
if (!BN_priv_rand_range_ex(priv_key, order, 0, ctx))
goto err;
while (BN_is_zero(priv_key)) ;
if (eckey->pub_key == NULL) {
pub_key = EC_POINT_new(group);
if (pub_key == NULL)
goto err;
} else
pub_key = eckey->pub_key;
/* Step (8) : pub_key = priv_key * G (where G is a point on the curve) */
if (!EC_POINT_mul(group, pub_key, priv_key, NULL, NULL, ctx))
goto err;
eckey->priv_key = priv_key;
eckey->pub_key = pub_key;
priv_key = NULL;
pub_key = NULL;
eckey->dirty_cnt++;
#ifdef FIPS_MODULE
pairwise_test = 1;
#endif /* FIPS_MODULE */
ok = 1;
if (pairwise_test) {
OSSL_CALLBACK *cb = NULL;
void *cbarg = NULL;
OSSL_SELF_TEST_get_callback(eckey->libctx, &cb, &cbarg);
ok = ecdsa_keygen_pairwise_test(eckey, cb, cbarg)
&& ecdsa_keygen_knownanswer_test(eckey, ctx, cb, cbarg);
}
err:
/* Step (9): If there is an error return an invalid keypair. */
if (!ok) {
ossl_set_error_state(OSSL_SELF_TEST_TYPE_PCT);
BN_clear(eckey->priv_key);
if (eckey->pub_key != NULL)
EC_POINT_set_to_infinity(group, eckey->pub_key);
}
EC_POINT_free(pub_key);
BN_clear_free(priv_key);
BN_CTX_free(ctx);
BN_free(order);
return ok;
}
#ifndef FIPS_MODULE
/*
* This is similar to ec_generate_key(), except it uses an ikm to
* derive the private key.
*/
int ossl_ec_generate_key_dhkem(EC_KEY *eckey,
const unsigned char *ikm, size_t ikmlen)
{
int ok = 0;
if (eckey->priv_key == NULL) {
eckey->priv_key = BN_secure_new();
if (eckey->priv_key == NULL)
goto err;
}
if (ossl_ec_dhkem_derive_private(eckey, eckey->priv_key, ikm, ikmlen) <= 0)
goto err;
if (eckey->pub_key == NULL) {
eckey->pub_key = EC_POINT_new(eckey->group);
if (eckey->pub_key == NULL)
goto err;
}
if (!ossl_ec_key_simple_generate_public_key(eckey))
goto err;
ok = 1;
err:
if (!ok) {
BN_clear_free(eckey->priv_key);
eckey->priv_key = NULL;
if (eckey->pub_key != NULL)
EC_POINT_set_to_infinity(eckey->group, eckey->pub_key);
}
return ok;
}
#endif
int ossl_ec_key_simple_generate_key(EC_KEY *eckey)
{
return ec_generate_key(eckey, 0);
}
int ossl_ec_key_simple_generate_public_key(EC_KEY *eckey)
{
int ret;
BN_CTX *ctx = BN_CTX_new_ex(eckey->libctx);
if (ctx == NULL)
return 0;
/*
* See SP800-56AR3 5.6.1.2.2: Step (8)
* pub_key = priv_key * G (where G is a point on the curve)
*/
ret = EC_POINT_mul(eckey->group, eckey->pub_key, eckey->priv_key, NULL,
NULL, ctx);
BN_CTX_free(ctx);
if (ret == 1)
eckey->dirty_cnt++;
return ret;
}
int EC_KEY_check_key(const EC_KEY *eckey)
{
if (eckey == NULL || eckey->group == NULL || eckey->pub_key == NULL) {
ERR_raise(ERR_LIB_EC, ERR_R_PASSED_NULL_PARAMETER);
return 0;
}
if (eckey->group->meth->keycheck == NULL) {
ERR_raise(ERR_LIB_EC, ERR_R_SHOULD_NOT_HAVE_BEEN_CALLED);
return 0;
}
return eckey->group->meth->keycheck(eckey);
}
/*
* Check the range of the EC public key.
* See SP800-56A R3 Section 5.6.2.3.3 (Part 2)
* i.e.
* - If q = odd prime p: Verify that xQ and yQ are integers in the
* interval[0, p - 1], OR
* - If q = 2m: Verify that xQ and yQ are bit strings of length m bits.
* Returns 1 if the public key has a valid range, otherwise it returns 0.
*/
static int ec_key_public_range_check(BN_CTX *ctx, const EC_KEY *key)
{
int ret = 0;
BIGNUM *x, *y;
BN_CTX_start(ctx);
x = BN_CTX_get(ctx);
y = BN_CTX_get(ctx);
if (y == NULL)
goto err;
if (!EC_POINT_get_affine_coordinates(key->group, key->pub_key, x, y, ctx))
goto err;
if (EC_GROUP_get_field_type(key->group) == NID_X9_62_prime_field) {
if (BN_is_negative(x)
|| BN_cmp(x, key->group->field) >= 0
|| BN_is_negative(y)
|| BN_cmp(y, key->group->field) >= 0) {
goto err;
}
} else {
int m = EC_GROUP_get_degree(key->group);
if (BN_num_bits(x) > m || BN_num_bits(y) > m) {
goto err;
}
}
ret = 1;
err:
BN_CTX_end(ctx);
return ret;
}
/*
* ECC Partial Public-Key Validation as specified in SP800-56A R3
* Section 5.6.2.3.4 ECC Partial Public-Key Validation Routine.
*/
int ossl_ec_key_public_check_quick(const EC_KEY *eckey, BN_CTX *ctx)
{
if (eckey == NULL || eckey->group == NULL || eckey->pub_key == NULL) {
ERR_raise(ERR_LIB_EC, ERR_R_PASSED_NULL_PARAMETER);
return 0;
}
/* 5.6.2.3.3 (Step 1): Q != infinity */
if (EC_POINT_is_at_infinity(eckey->group, eckey->pub_key)) {
ERR_raise(ERR_LIB_EC, EC_R_POINT_AT_INFINITY);
return 0;
}
/* 5.6.2.3.3 (Step 2) Test if the public key is in range */
if (!ec_key_public_range_check(ctx, eckey)) {
ERR_raise(ERR_LIB_EC, EC_R_COORDINATES_OUT_OF_RANGE);
return 0;
}
/* 5.6.2.3.3 (Step 3) is the pub_key on the elliptic curve */
if (EC_POINT_is_on_curve(eckey->group, eckey->pub_key, ctx) <= 0) {
ERR_raise(ERR_LIB_EC, EC_R_POINT_IS_NOT_ON_CURVE);
return 0;
}
return 1;
}
/*
* ECC Key validation as specified in SP800-56A R3.
* Section 5.6.2.3.3 ECC Full Public-Key Validation Routine.
*/
int ossl_ec_key_public_check(const EC_KEY *eckey, BN_CTX *ctx)
{
int ret = 0;
EC_POINT *point = NULL;
const BIGNUM *order = NULL;
const BIGNUM *cofactor = EC_GROUP_get0_cofactor(eckey->group);
if (!ossl_ec_key_public_check_quick(eckey, ctx))
return 0;
if (cofactor != NULL && BN_is_one(cofactor)) {
/* Skip the unnecessary expensive computation for curves with cofactor of 1. */
return 1;
}
point = EC_POINT_new(eckey->group);
if (point == NULL)
return 0;
order = eckey->group->order;
if (BN_is_zero(order)) {
ERR_raise(ERR_LIB_EC, EC_R_INVALID_GROUP_ORDER);
goto err;
}
/* 5.6.2.3.3 (Step 4) : pub_key * order is the point at infinity. */
if (!EC_POINT_mul(eckey->group, point, NULL, eckey->pub_key, order, ctx)) {
ERR_raise(ERR_LIB_EC, ERR_R_EC_LIB);
goto err;
}
if (!EC_POINT_is_at_infinity(eckey->group, point)) {
ERR_raise(ERR_LIB_EC, EC_R_WRONG_ORDER);
goto err;
}
ret = 1;
err:
EC_POINT_free(point);
return ret;
}
/*
* ECC Key validation as specified in SP800-56A R3.
* Section 5.6.2.1.2 Owner Assurance of Private-Key Validity
* The private key is in the range [1, order-1]
*/
int ossl_ec_key_private_check(const EC_KEY *eckey)
{
if (eckey == NULL || eckey->group == NULL || eckey->priv_key == NULL) {
ERR_raise(ERR_LIB_EC, ERR_R_PASSED_NULL_PARAMETER);
return 0;
}
if (BN_cmp(eckey->priv_key, BN_value_one()) < 0
|| BN_cmp(eckey->priv_key, eckey->group->order) >= 0) {
ERR_raise(ERR_LIB_EC, EC_R_INVALID_PRIVATE_KEY);
return 0;
}
return 1;
}
/*
* ECC Key validation as specified in SP800-56A R3.
* Section 5.6.2.1.4 Owner Assurance of Pair-wise Consistency (b)
* Check if generator * priv_key = pub_key
*/
int ossl_ec_key_pairwise_check(const EC_KEY *eckey, BN_CTX *ctx)
{
int ret = 0;
EC_POINT *point = NULL;
if (eckey == NULL
|| eckey->group == NULL
|| eckey->pub_key == NULL
|| eckey->priv_key == NULL) {
ERR_raise(ERR_LIB_EC, ERR_R_PASSED_NULL_PARAMETER);
return 0;
}
point = EC_POINT_new(eckey->group);
if (point == NULL)
goto err;
if (!EC_POINT_mul(eckey->group, point, eckey->priv_key, NULL, NULL, ctx)) {
ERR_raise(ERR_LIB_EC, ERR_R_EC_LIB);
goto err;
}
if (EC_POINT_cmp(eckey->group, point, eckey->pub_key, ctx) != 0) {
ERR_raise(ERR_LIB_EC, EC_R_INVALID_PRIVATE_KEY);
goto err;
}
ret = 1;
err:
EC_POINT_free(point);
return ret;
}
/*
* ECC Key validation as specified in SP800-56A R3.
* Section 5.6.2.3.3 ECC Full Public-Key Validation
* Section 5.6.2.1.2 Owner Assurance of Private-Key Validity
* Section 5.6.2.1.4 Owner Assurance of Pair-wise Consistency
* NOTES:
* Before calling this method in fips mode, there should be an assurance that
* an approved elliptic-curve group is used.
* Returns 1 if the key is valid, otherwise it returns 0.
*/
int ossl_ec_key_simple_check_key(const EC_KEY *eckey)
{
int ok = 0;
BN_CTX *ctx = NULL;
if (eckey == NULL) {
ERR_raise(ERR_LIB_EC, ERR_R_PASSED_NULL_PARAMETER);
return 0;
}
if ((ctx = BN_CTX_new_ex(eckey->libctx)) == NULL)
return 0;
if (!ossl_ec_key_public_check(eckey, ctx))
goto err;
if (eckey->priv_key != NULL) {
if (!ossl_ec_key_private_check(eckey)
|| !ossl_ec_key_pairwise_check(eckey, ctx))
goto err;
}
ok = 1;
err:
BN_CTX_free(ctx);
return ok;
}
int EC_KEY_set_public_key_affine_coordinates(EC_KEY *key, BIGNUM *x,
BIGNUM *y)
{
BN_CTX *ctx = NULL;
BIGNUM *tx, *ty;
EC_POINT *point = NULL;
int ok = 0;
if (key == NULL || key->group == NULL || x == NULL || y == NULL) {
ERR_raise(ERR_LIB_EC, ERR_R_PASSED_NULL_PARAMETER);
return 0;
}
ctx = BN_CTX_new_ex(key->libctx);
if (ctx == NULL)
return 0;
BN_CTX_start(ctx);
point = EC_POINT_new(key->group);
if (point == NULL)
goto err;
tx = BN_CTX_get(ctx);
ty = BN_CTX_get(ctx);
if (ty == NULL)
goto err;
if (!EC_POINT_set_affine_coordinates(key->group, point, x, y, ctx))
goto err;
if (!EC_POINT_get_affine_coordinates(key->group, point, tx, ty, ctx))
goto err;
/*
* Check if retrieved coordinates match originals. The range check is done
* inside EC_KEY_check_key().
*/
if (BN_cmp(x, tx) || BN_cmp(y, ty)) {
ERR_raise(ERR_LIB_EC, EC_R_COORDINATES_OUT_OF_RANGE);
goto err;
}
/* EC_KEY_set_public_key updates dirty_cnt */
if (!EC_KEY_set_public_key(key, point))
goto err;
if (EC_KEY_check_key(key) == 0)
goto err;
ok = 1;
err:
BN_CTX_end(ctx);
BN_CTX_free(ctx);
EC_POINT_free(point);
return ok;
}
OSSL_LIB_CTX *ossl_ec_key_get_libctx(const EC_KEY *key)
{
return key->libctx;
}
const char *ossl_ec_key_get0_propq(const EC_KEY *key)
{
return key->propq;
}
void ossl_ec_key_set0_libctx(EC_KEY *key, OSSL_LIB_CTX *libctx)
{
key->libctx = libctx;
/* Do we need to propagate this to the group? */
}
const EC_GROUP *EC_KEY_get0_group(const EC_KEY *key)
{
return key->group;
}
int EC_KEY_set_group(EC_KEY *key, const EC_GROUP *group)
{
if (key->meth->set_group != NULL && key->meth->set_group(key, group) == 0)
return 0;
EC_GROUP_free(key->group);
key->group = EC_GROUP_dup(group);
if (key->group != NULL && EC_GROUP_get_curve_name(key->group) == NID_sm2)
EC_KEY_set_flags(key, EC_FLAG_SM2_RANGE);
key->dirty_cnt++;
return (key->group == NULL) ? 0 : 1;
}
const BIGNUM *EC_KEY_get0_private_key(const EC_KEY *key)
{
return key->priv_key;
}
int EC_KEY_set_private_key(EC_KEY *key, const BIGNUM *priv_key)
{
int fixed_top;
const BIGNUM *order = NULL;
BIGNUM *tmp_key = NULL;
if (key->group == NULL || key->group->meth == NULL)
return 0;
/*
* Not only should key->group be set, but it should also be in a valid
* fully initialized state.
*
* Specifically, to operate in constant time, we need that the group order
* is set, as we use its length as the fixed public size of any scalar used
* as an EC private key.
*/
order = EC_GROUP_get0_order(key->group);
if (order == NULL || BN_is_zero(order))
return 0; /* This should never happen */
if (key->group->meth->set_private != NULL
&& key->group->meth->set_private(key, priv_key) == 0)
return 0;
if (key->meth->set_private != NULL
&& key->meth->set_private(key, priv_key) == 0)
return 0;
/*
* Return `0` to comply with legacy behavior for this function, see
* https://github.com/openssl/openssl/issues/18744#issuecomment-1195175696
*/
if (priv_key == NULL) {
BN_clear_free(key->priv_key);
key->priv_key = NULL;
return 0; /* intentional for legacy compatibility */
}
/*
* We should never leak the bit length of the secret scalar in the key,
* so we always set the `BN_FLG_CONSTTIME` flag on the internal `BIGNUM`
* holding the secret scalar.
*
* This is important also because `BN_dup()` (and `BN_copy()`) do not
* propagate the `BN_FLG_CONSTTIME` flag from the source `BIGNUM`, and
* this brings an extra risk of inadvertently losing the flag, even when
* the caller specifically set it.
*
* The propagation has been turned on and off a few times in the past
* years because in some conditions has shown unintended consequences in
* some code paths, so at the moment we can't fix this in the BN layer.
*
* In `EC_KEY_set_private_key()` we can work around the propagation by
* manually setting the flag after `BN_dup()` as we know for sure that
* inside the EC module the `BN_FLG_CONSTTIME` is always treated
* correctly and should not generate unintended consequences.
*
* Setting the BN_FLG_CONSTTIME flag alone is never enough, we also have
* to preallocate the BIGNUM internal buffer to a fixed public size big
* enough that operations performed during the processing never trigger
* a realloc which would leak the size of the scalar through memory
* accesses.
*
* Fixed Length
* ------------
*
* The order of the large prime subgroup of the curve is our choice for
* a fixed public size, as that is generally the upper bound for
* generating a private key in EC cryptosystems and should fit all valid
* secret scalars.
*
* For preallocating the BIGNUM storage we look at the number of "words"
* required for the internal representation of the order, and we
* preallocate 2 extra "words" in case any of the subsequent processing
* might temporarily overflow the order length.
*/
tmp_key = BN_dup(priv_key);
if (tmp_key == NULL)
return 0;
BN_set_flags(tmp_key, BN_FLG_CONSTTIME);
fixed_top = bn_get_top(order) + 2;
if (bn_wexpand(tmp_key, fixed_top) == NULL) {
BN_clear_free(tmp_key);
return 0;
}
BN_clear_free(key->priv_key);
key->priv_key = tmp_key;
key->dirty_cnt++;
return 1;
}
const EC_POINT *EC_KEY_get0_public_key(const EC_KEY *key)
{
return key->pub_key;
}
int EC_KEY_set_public_key(EC_KEY *key, const EC_POINT *pub_key)
{
if (key->meth->set_public != NULL
&& key->meth->set_public(key, pub_key) == 0)
return 0;
EC_POINT_free(key->pub_key);
key->pub_key = EC_POINT_dup(pub_key, key->group);
key->dirty_cnt++;
return (key->pub_key == NULL) ? 0 : 1;
}
unsigned int EC_KEY_get_enc_flags(const EC_KEY *key)
{
return key->enc_flag;
}
void EC_KEY_set_enc_flags(EC_KEY *key, unsigned int flags)
{
key->enc_flag = flags;
}
point_conversion_form_t EC_KEY_get_conv_form(const EC_KEY *key)
{
return key->conv_form;
}
void EC_KEY_set_conv_form(EC_KEY *key, point_conversion_form_t cform)
{
key->conv_form = cform;
if (key->group != NULL)
EC_GROUP_set_point_conversion_form(key->group, cform);
}
void EC_KEY_set_asn1_flag(EC_KEY *key, int flag)
{
if (key->group != NULL)
EC_GROUP_set_asn1_flag(key->group, flag);
}
#ifndef OPENSSL_NO_DEPRECATED_3_0
int EC_KEY_precompute_mult(EC_KEY *key, BN_CTX *ctx)
{
if (key->group == NULL)
return 0;
return EC_GROUP_precompute_mult(key->group, ctx);
}
#endif
int EC_KEY_get_flags(const EC_KEY *key)
{
return key->flags;
}
void EC_KEY_set_flags(EC_KEY *key, int flags)
{
key->flags |= flags;
key->dirty_cnt++;
}
void EC_KEY_clear_flags(EC_KEY *key, int flags)
{
key->flags &= ~flags;
key->dirty_cnt++;
}
int EC_KEY_decoded_from_explicit_params(const EC_KEY *key)
{
if (key == NULL || key->group == NULL)
return -1;
return key->group->decoded_from_explicit_params;
}
size_t EC_KEY_key2buf(const EC_KEY *key, point_conversion_form_t form,
unsigned char **pbuf, BN_CTX *ctx)
{
if (key == NULL || key->pub_key == NULL || key->group == NULL)
return 0;
return EC_POINT_point2buf(key->group, key->pub_key, form, pbuf, ctx);
}
int EC_KEY_oct2key(EC_KEY *key, const unsigned char *buf, size_t len,
BN_CTX *ctx)
{
if (key == NULL || key->group == NULL)
return 0;
if (key->pub_key == NULL)
key->pub_key = EC_POINT_new(key->group);
if (key->pub_key == NULL)
return 0;
if (EC_POINT_oct2point(key->group, key->pub_key, buf, len, ctx) == 0)
return 0;
key->dirty_cnt++;
/*
* Save the point conversion form.
* For non-custom curves the first octet of the buffer (excluding
* the last significant bit) contains the point conversion form.
* EC_POINT_oct2point() has already performed sanity checking of
* the buffer so we know it is valid.
*/
if ((key->group->meth->flags & EC_FLAGS_CUSTOM_CURVE) == 0)
key->conv_form = (point_conversion_form_t)(buf[0] & ~0x01);
return 1;
}
size_t EC_KEY_priv2oct(const EC_KEY *eckey,
unsigned char *buf, size_t len)
{
if (eckey->group == NULL || eckey->group->meth == NULL)
return 0;
if (eckey->group->meth->priv2oct == NULL) {
ERR_raise(ERR_LIB_EC, ERR_R_SHOULD_NOT_HAVE_BEEN_CALLED);
return 0;
}
return eckey->group->meth->priv2oct(eckey, buf, len);
}
size_t ossl_ec_key_simple_priv2oct(const EC_KEY *eckey,
unsigned char *buf, size_t len)
{
size_t buf_len;
buf_len = (EC_GROUP_order_bits(eckey->group) + 7) / 8;
if (eckey->priv_key == NULL)
return 0;
if (buf == NULL)
return buf_len;
else if (len < buf_len)
return 0;
/* Octetstring may need leading zeros if BN is to short */
if (BN_bn2binpad(eckey->priv_key, buf, buf_len) == -1) {
ERR_raise(ERR_LIB_EC, EC_R_BUFFER_TOO_SMALL);
return 0;
}
return buf_len;
}
int EC_KEY_oct2priv(EC_KEY *eckey, const unsigned char *buf, size_t len)
{
int ret;
if (eckey->group == NULL || eckey->group->meth == NULL)
return 0;
if (eckey->group->meth->oct2priv == NULL) {
ERR_raise(ERR_LIB_EC, ERR_R_SHOULD_NOT_HAVE_BEEN_CALLED);
return 0;
}
ret = eckey->group->meth->oct2priv(eckey, buf, len);
if (ret == 1)
eckey->dirty_cnt++;
return ret;
}
int ossl_ec_key_simple_oct2priv(EC_KEY *eckey, const unsigned char *buf,
size_t len)
{
if (eckey->priv_key == NULL)
eckey->priv_key = BN_secure_new();
if (eckey->priv_key == NULL) {
ERR_raise(ERR_LIB_EC, ERR_R_BN_LIB);
return 0;
}
if (BN_bin2bn(buf, len, eckey->priv_key) == NULL) {
ERR_raise(ERR_LIB_EC, ERR_R_BN_LIB);
return 0;
}
eckey->dirty_cnt++;
return 1;
}
size_t EC_KEY_priv2buf(const EC_KEY *eckey, unsigned char **pbuf)
{
size_t len;
unsigned char *buf;
len = EC_KEY_priv2oct(eckey, NULL, 0);
if (len == 0)
return 0;
if ((buf = OPENSSL_malloc(len)) == NULL)
return 0;
len = EC_KEY_priv2oct(eckey, buf, len);
if (len == 0) {
OPENSSL_free(buf);
return 0;
}
*pbuf = buf;
return len;
}
int EC_KEY_can_sign(const EC_KEY *eckey)
{
if (eckey->group == NULL || eckey->group->meth == NULL
|| (eckey->group->meth->flags & EC_FLAGS_NO_SIGN))
return 0;
return 1;
}
/*
* FIPS 140-2 IG 9.9 AS09.33
* Perform a sign/verify operation.
*
* NOTE: When generating keys for key-agreement schemes - FIPS 140-2 IG 9.9
* states that no additional pairwise tests are required (apart from the tests
* specified in SP800-56A) when generating keys. Hence pairwise ECDH tests are
* omitted here.
*/
static int ecdsa_keygen_pairwise_test(EC_KEY *eckey, OSSL_CALLBACK *cb,
void *cbarg)
{
int ret = 0;
unsigned char dgst[16] = {0};
int dgst_len = (int)sizeof(dgst);
ECDSA_SIG *sig = NULL;
OSSL_SELF_TEST *st = NULL;
st = OSSL_SELF_TEST_new(cb, cbarg);
if (st == NULL)
return 0;
OSSL_SELF_TEST_onbegin(st, OSSL_SELF_TEST_TYPE_PCT,
OSSL_SELF_TEST_DESC_PCT_ECDSA);
sig = ECDSA_do_sign(dgst, dgst_len, eckey);
if (sig == NULL)
goto err;
OSSL_SELF_TEST_oncorrupt_byte(st, dgst);
if (ECDSA_do_verify(dgst, dgst_len, sig, eckey) != 1)
goto err;
ret = 1;
err:
OSSL_SELF_TEST_onend(st, ret);
OSSL_SELF_TEST_free(st);
ECDSA_SIG_free(sig);
return ret;
}
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