531 lines
16 KiB
C
531 lines
16 KiB
C
|
/*
|
||
|
|
* Copyright 2002-2023 The OpenSSL Project Authors. 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
|
||
|
|
*/
|
||
|
|
|
||
|
|
/*
|
||
|
|
* ECDSA low level APIs are deprecated for public use, but still ok for
|
||
|
|
* internal use.
|
||
|
|
*/
|
||
|
|
#include "internal/deprecated.h"
|
||
|
|
|
||
|
|
#include <string.h>
|
||
|
|
#include <openssl/err.h>
|
||
|
|
#include <openssl/obj_mac.h>
|
||
|
|
#include <openssl/rand.h>
|
||
|
|
#include "crypto/bn.h"
|
||
|
|
#include "ec_local.h"
|
||
|
|
#include "internal/deterministic_nonce.h"
|
||
|
|
|
||
|
|
#define MIN_ECDSA_SIGN_ORDERBITS 64
|
||
|
|
/*
|
||
|
|
* It is highly unlikely that a retry will happen,
|
||
|
|
* Multiple retries would indicate that something is wrong
|
||
|
|
* with the group parameters (which would normally only happen
|
||
|
|
* with a bad custom group).
|
||
|
|
*/
|
||
|
|
#define MAX_ECDSA_SIGN_RETRIES 8
|
||
|
|
|
||
|
|
static int ecdsa_sign_setup(EC_KEY *eckey, BN_CTX *ctx_in,
|
||
|
|
BIGNUM **kinvp, BIGNUM **rp,
|
||
|
|
const unsigned char *dgst, int dlen,
|
||
|
|
unsigned int nonce_type, const char *digestname,
|
||
|
|
OSSL_LIB_CTX *libctx, const char *propq);
|
||
|
|
|
||
|
|
int ossl_ecdsa_sign_setup(EC_KEY *eckey, BN_CTX *ctx_in, BIGNUM **kinvp,
|
||
|
|
BIGNUM **rp)
|
||
|
|
{
|
||
|
|
if (eckey->group->meth->ecdsa_sign_setup == NULL) {
|
||
|
|
ERR_raise(ERR_LIB_EC, EC_R_CURVE_DOES_NOT_SUPPORT_ECDSA);
|
||
|
|
return 0;
|
||
|
|
}
|
||
|
|
|
||
|
|
return eckey->group->meth->ecdsa_sign_setup(eckey, ctx_in, kinvp, rp);
|
||
|
|
}
|
||
|
|
|
||
|
|
ECDSA_SIG *ossl_ecdsa_sign_sig(const unsigned char *dgst, int dgst_len,
|
||
|
|
const BIGNUM *in_kinv, const BIGNUM *in_r,
|
||
|
|
EC_KEY *eckey)
|
||
|
|
{
|
||
|
|
if (eckey->group->meth->ecdsa_sign_sig == NULL) {
|
||
|
|
ERR_raise(ERR_LIB_EC, EC_R_CURVE_DOES_NOT_SUPPORT_ECDSA);
|
||
|
|
return NULL;
|
||
|
|
}
|
||
|
|
|
||
|
|
return eckey->group->meth->ecdsa_sign_sig(dgst, dgst_len,
|
||
|
|
in_kinv, in_r, eckey);
|
||
|
|
}
|
||
|
|
|
||
|
|
int ossl_ecdsa_verify_sig(const unsigned char *dgst, int dgst_len,
|
||
|
|
const ECDSA_SIG *sig, EC_KEY *eckey)
|
||
|
|
{
|
||
|
|
if (eckey->group->meth->ecdsa_verify_sig == NULL) {
|
||
|
|
ERR_raise(ERR_LIB_EC, EC_R_CURVE_DOES_NOT_SUPPORT_ECDSA);
|
||
|
|
return 0;
|
||
|
|
}
|
||
|
|
|
||
|
|
return eckey->group->meth->ecdsa_verify_sig(dgst, dgst_len, sig, eckey);
|
||
|
|
}
|
||
|
|
|
||
|
|
int ossl_ecdsa_sign(int type, const unsigned char *dgst, int dlen,
|
||
|
|
unsigned char *sig, unsigned int *siglen,
|
||
|
|
const BIGNUM *kinv, const BIGNUM *r, EC_KEY *eckey)
|
||
|
|
{
|
||
|
|
ECDSA_SIG *s;
|
||
|
|
|
||
|
|
s = ECDSA_do_sign_ex(dgst, dlen, kinv, r, eckey);
|
||
|
|
if (s == NULL) {
|
||
|
|
*siglen = 0;
|
||
|
|
return 0;
|
||
|
|
}
|
||
|
|
*siglen = i2d_ECDSA_SIG(s, sig != NULL ? &sig : NULL);
|
||
|
|
ECDSA_SIG_free(s);
|
||
|
|
return 1;
|
||
|
|
}
|
||
|
|
|
||
|
|
int ossl_ecdsa_deterministic_sign(const unsigned char *dgst, int dlen,
|
||
|
|
unsigned char *sig, unsigned int *siglen,
|
||
|
|
EC_KEY *eckey, unsigned int nonce_type,
|
||
|
|
const char *digestname,
|
||
|
|
OSSL_LIB_CTX *libctx, const char *propq)
|
||
|
|
{
|
||
|
|
ECDSA_SIG *s;
|
||
|
|
BIGNUM *kinv = NULL, *r = NULL;
|
||
|
|
int ret = 0;
|
||
|
|
|
||
|
|
*siglen = 0;
|
||
|
|
if (!ecdsa_sign_setup(eckey, NULL, &kinv, &r, dgst, dlen,
|
||
|
|
nonce_type, digestname, libctx, propq))
|
||
|
|
return 0;
|
||
|
|
|
||
|
|
s = ECDSA_do_sign_ex(dgst, dlen, kinv, r, eckey);
|
||
|
|
if (s == NULL)
|
||
|
|
goto end;
|
||
|
|
|
||
|
|
*siglen = i2d_ECDSA_SIG(s, sig != NULL ? &sig : NULL);
|
||
|
|
ECDSA_SIG_free(s);
|
||
|
|
ret = 1;
|
||
|
|
end:
|
||
|
|
BN_clear_free(kinv);
|
||
|
|
BN_clear_free(r);
|
||
|
|
return ret;
|
||
|
|
}
|
||
|
|
|
||
|
|
static int ecdsa_sign_setup(EC_KEY *eckey, BN_CTX *ctx_in,
|
||
|
|
BIGNUM **kinvp, BIGNUM **rp,
|
||
|
|
const unsigned char *dgst, int dlen,
|
||
|
|
unsigned int nonce_type, const char *digestname,
|
||
|
|
OSSL_LIB_CTX *libctx, const char *propq)
|
||
|
|
{
|
||
|
|
BN_CTX *ctx = NULL;
|
||
|
|
BIGNUM *k = NULL, *r = NULL, *X = NULL;
|
||
|
|
const BIGNUM *order;
|
||
|
|
EC_POINT *tmp_point = NULL;
|
||
|
|
const EC_GROUP *group;
|
||
|
|
int ret = 0;
|
||
|
|
int order_bits;
|
||
|
|
const BIGNUM *priv_key;
|
||
|
|
|
||
|
|
if (eckey == NULL || (group = EC_KEY_get0_group(eckey)) == NULL) {
|
||
|
|
ERR_raise(ERR_LIB_EC, ERR_R_PASSED_NULL_PARAMETER);
|
||
|
|
return 0;
|
||
|
|
}
|
||
|
|
if ((priv_key = EC_KEY_get0_private_key(eckey)) == NULL) {
|
||
|
|
ERR_raise(ERR_LIB_EC, EC_R_MISSING_PRIVATE_KEY);
|
||
|
|
return 0;
|
||
|
|
}
|
||
|
|
|
||
|
|
if (!EC_KEY_can_sign(eckey)) {
|
||
|
|
ERR_raise(ERR_LIB_EC, EC_R_CURVE_DOES_NOT_SUPPORT_SIGNING);
|
||
|
|
return 0;
|
||
|
|
}
|
||
|
|
|
||
|
|
if ((ctx = ctx_in) == NULL) {
|
||
|
|
if ((ctx = BN_CTX_new_ex(eckey->libctx)) == NULL) {
|
||
|
|
ERR_raise(ERR_LIB_EC, ERR_R_BN_LIB);
|
||
|
|
return 0;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
k = BN_secure_new(); /* this value is later returned in *kinvp */
|
||
|
|
r = BN_new(); /* this value is later returned in *rp */
|
||
|
|
X = BN_new();
|
||
|
|
if (k == NULL || r == NULL || X == NULL) {
|
||
|
|
ERR_raise(ERR_LIB_EC, ERR_R_BN_LIB);
|
||
|
|
goto err;
|
||
|
|
}
|
||
|
|
if ((tmp_point = EC_POINT_new(group)) == NULL) {
|
||
|
|
ERR_raise(ERR_LIB_EC, ERR_R_EC_LIB);
|
||
|
|
goto err;
|
||
|
|
}
|
||
|
|
order = EC_GROUP_get0_order(group);
|
||
|
|
|
||
|
|
/* Preallocate space */
|
||
|
|
order_bits = BN_num_bits(order);
|
||
|
|
/* Check the number of bits here so that an infinite loop is not possible */
|
||
|
|
if (order_bits < MIN_ECDSA_SIGN_ORDERBITS
|
||
|
|
|| !BN_set_bit(k, order_bits)
|
||
|
|
|| !BN_set_bit(r, order_bits)
|
||
|
|
|| !BN_set_bit(X, order_bits))
|
||
|
|
goto err;
|
||
|
|
|
||
|
|
do {
|
||
|
|
/* get random or deterministic value of k */
|
||
|
|
do {
|
||
|
|
int res = 0;
|
||
|
|
|
||
|
|
if (dgst != NULL) {
|
||
|
|
if (nonce_type == 1) {
|
||
|
|
#ifndef FIPS_MODULE
|
||
|
|
res = ossl_gen_deterministic_nonce_rfc6979(k, order,
|
||
|
|
priv_key,
|
||
|
|
dgst, dlen,
|
||
|
|
digestname,
|
||
|
|
libctx, propq);
|
||
|
|
#endif
|
||
|
|
} else {
|
||
|
|
res = BN_generate_dsa_nonce(k, order, priv_key, dgst, dlen,
|
||
|
|
ctx);
|
||
|
|
}
|
||
|
|
} else {
|
||
|
|
res = BN_priv_rand_range_ex(k, order, 0, ctx);
|
||
|
|
}
|
||
|
|
if (!res) {
|
||
|
|
ERR_raise(ERR_LIB_EC, EC_R_RANDOM_NUMBER_GENERATION_FAILED);
|
||
|
|
goto err;
|
||
|
|
}
|
||
|
|
} while (BN_is_zero(k));
|
||
|
|
|
||
|
|
/* compute r the x-coordinate of generator * k */
|
||
|
|
if (!EC_POINT_mul(group, tmp_point, k, NULL, NULL, ctx)) {
|
||
|
|
ERR_raise(ERR_LIB_EC, ERR_R_EC_LIB);
|
||
|
|
goto err;
|
||
|
|
}
|
||
|
|
|
||
|
|
if (!EC_POINT_get_affine_coordinates(group, tmp_point, X, NULL, ctx)) {
|
||
|
|
ERR_raise(ERR_LIB_EC, ERR_R_EC_LIB);
|
||
|
|
goto err;
|
||
|
|
}
|
||
|
|
|
||
|
|
if (!BN_nnmod(r, X, order, ctx)) {
|
||
|
|
ERR_raise(ERR_LIB_EC, ERR_R_BN_LIB);
|
||
|
|
goto err;
|
||
|
|
}
|
||
|
|
} while (BN_is_zero(r));
|
||
|
|
|
||
|
|
/* compute the inverse of k */
|
||
|
|
if (!ossl_ec_group_do_inverse_ord(group, k, k, ctx)) {
|
||
|
|
ERR_raise(ERR_LIB_EC, ERR_R_BN_LIB);
|
||
|
|
goto err;
|
||
|
|
}
|
||
|
|
|
||
|
|
/* clear old values if necessary */
|
||
|
|
BN_clear_free(*rp);
|
||
|
|
BN_clear_free(*kinvp);
|
||
|
|
/* save the pre-computed values */
|
||
|
|
*rp = r;
|
||
|
|
*kinvp = k;
|
||
|
|
ret = 1;
|
||
|
|
err:
|
||
|
|
if (!ret) {
|
||
|
|
BN_clear_free(k);
|
||
|
|
BN_clear_free(r);
|
||
|
|
}
|
||
|
|
if (ctx != ctx_in)
|
||
|
|
BN_CTX_free(ctx);
|
||
|
|
EC_POINT_free(tmp_point);
|
||
|
|
BN_clear_free(X);
|
||
|
|
return ret;
|
||
|
|
}
|
||
|
|
|
||
|
|
int ossl_ecdsa_simple_sign_setup(EC_KEY *eckey, BN_CTX *ctx_in, BIGNUM **kinvp,
|
||
|
|
BIGNUM **rp)
|
||
|
|
{
|
||
|
|
return ecdsa_sign_setup(eckey, ctx_in, kinvp, rp, NULL, 0,
|
||
|
|
0, NULL, NULL, NULL);
|
||
|
|
}
|
||
|
|
|
||
|
|
ECDSA_SIG *ossl_ecdsa_simple_sign_sig(const unsigned char *dgst, int dgst_len,
|
||
|
|
const BIGNUM *in_kinv, const BIGNUM *in_r,
|
||
|
|
EC_KEY *eckey)
|
||
|
|
{
|
||
|
|
int ok = 0, i;
|
||
|
|
int retries = 0;
|
||
|
|
BIGNUM *kinv = NULL, *s, *m = NULL;
|
||
|
|
const BIGNUM *order, *ckinv;
|
||
|
|
BN_CTX *ctx = NULL;
|
||
|
|
const EC_GROUP *group;
|
||
|
|
ECDSA_SIG *ret;
|
||
|
|
const BIGNUM *priv_key;
|
||
|
|
|
||
|
|
group = EC_KEY_get0_group(eckey);
|
||
|
|
priv_key = EC_KEY_get0_private_key(eckey);
|
||
|
|
|
||
|
|
if (group == NULL) {
|
||
|
|
ERR_raise(ERR_LIB_EC, ERR_R_PASSED_NULL_PARAMETER);
|
||
|
|
return NULL;
|
||
|
|
}
|
||
|
|
if (priv_key == NULL) {
|
||
|
|
ERR_raise(ERR_LIB_EC, EC_R_MISSING_PRIVATE_KEY);
|
||
|
|
return NULL;
|
||
|
|
}
|
||
|
|
|
||
|
|
if (!EC_KEY_can_sign(eckey)) {
|
||
|
|
ERR_raise(ERR_LIB_EC, EC_R_CURVE_DOES_NOT_SUPPORT_SIGNING);
|
||
|
|
return NULL;
|
||
|
|
}
|
||
|
|
|
||
|
|
ret = ECDSA_SIG_new();
|
||
|
|
if (ret == NULL) {
|
||
|
|
ERR_raise(ERR_LIB_EC, ERR_R_ECDSA_LIB);
|
||
|
|
return NULL;
|
||
|
|
}
|
||
|
|
ret->r = BN_new();
|
||
|
|
ret->s = BN_new();
|
||
|
|
if (ret->r == NULL || ret->s == NULL) {
|
||
|
|
ERR_raise(ERR_LIB_EC, ERR_R_BN_LIB);
|
||
|
|
goto err;
|
||
|
|
}
|
||
|
|
s = ret->s;
|
||
|
|
|
||
|
|
if ((ctx = BN_CTX_new_ex(eckey->libctx)) == NULL
|
||
|
|
|| (m = BN_new()) == NULL) {
|
||
|
|
ERR_raise(ERR_LIB_EC, ERR_R_BN_LIB);
|
||
|
|
goto err;
|
||
|
|
}
|
||
|
|
|
||
|
|
order = EC_GROUP_get0_order(group);
|
||
|
|
i = BN_num_bits(order);
|
||
|
|
/*
|
||
|
|
* Need to truncate digest if it is too long: first truncate whole bytes.
|
||
|
|
*/
|
||
|
|
if (8 * dgst_len > i)
|
||
|
|
dgst_len = (i + 7) / 8;
|
||
|
|
if (!BN_bin2bn(dgst, dgst_len, m)) {
|
||
|
|
ERR_raise(ERR_LIB_EC, ERR_R_BN_LIB);
|
||
|
|
goto err;
|
||
|
|
}
|
||
|
|
/* If still too long, truncate remaining bits with a shift */
|
||
|
|
if ((8 * dgst_len > i) && !BN_rshift(m, m, 8 - (i & 0x7))) {
|
||
|
|
ERR_raise(ERR_LIB_EC, ERR_R_BN_LIB);
|
||
|
|
goto err;
|
||
|
|
}
|
||
|
|
do {
|
||
|
|
if (in_kinv == NULL || in_r == NULL) {
|
||
|
|
if (!ecdsa_sign_setup(eckey, ctx, &kinv, &ret->r, dgst, dgst_len,
|
||
|
|
0, NULL, NULL, NULL)) {
|
||
|
|
ERR_raise(ERR_LIB_EC, ERR_R_ECDSA_LIB);
|
||
|
|
goto err;
|
||
|
|
}
|
||
|
|
ckinv = kinv;
|
||
|
|
} else {
|
||
|
|
ckinv = in_kinv;
|
||
|
|
if (BN_copy(ret->r, in_r) == NULL) {
|
||
|
|
ERR_raise(ERR_LIB_EC, ERR_R_BN_LIB);
|
||
|
|
goto err;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
/*
|
||
|
|
* With only one multiplicant being in Montgomery domain
|
||
|
|
* multiplication yields real result without post-conversion.
|
||
|
|
* Also note that all operations but last are performed with
|
||
|
|
* zero-padded vectors. Last operation, BN_mod_mul_montgomery
|
||
|
|
* below, returns user-visible value with removed zero padding.
|
||
|
|
*/
|
||
|
|
if (!bn_to_mont_fixed_top(s, ret->r, group->mont_data, ctx)
|
||
|
|
|| !bn_mul_mont_fixed_top(s, s, priv_key, group->mont_data, ctx)) {
|
||
|
|
ERR_raise(ERR_LIB_EC, ERR_R_BN_LIB);
|
||
|
|
goto err;
|
||
|
|
}
|
||
|
|
if (!bn_mod_add_fixed_top(s, s, m, order)) {
|
||
|
|
ERR_raise(ERR_LIB_EC, ERR_R_BN_LIB);
|
||
|
|
goto err;
|
||
|
|
}
|
||
|
|
/*
|
||
|
|
* |s| can still be larger than modulus, because |m| can be. In
|
||
|
|
* such case we count on Montgomery reduction to tie it up.
|
||
|
|
*/
|
||
|
|
if (!bn_to_mont_fixed_top(s, s, group->mont_data, ctx)
|
||
|
|
|| !BN_mod_mul_montgomery(s, s, ckinv, group->mont_data, ctx)) {
|
||
|
|
ERR_raise(ERR_LIB_EC, ERR_R_BN_LIB);
|
||
|
|
goto err;
|
||
|
|
}
|
||
|
|
|
||
|
|
if (BN_is_zero(s)) {
|
||
|
|
/*
|
||
|
|
* if kinv and r have been supplied by the caller, don't
|
||
|
|
* generate new kinv and r values
|
||
|
|
*/
|
||
|
|
if (in_kinv != NULL && in_r != NULL) {
|
||
|
|
ERR_raise(ERR_LIB_EC, EC_R_NEED_NEW_SETUP_VALUES);
|
||
|
|
goto err;
|
||
|
|
}
|
||
|
|
/* Avoid infinite loops cause by invalid group parameters */
|
||
|
|
if (retries++ > MAX_ECDSA_SIGN_RETRIES) {
|
||
|
|
ERR_raise(ERR_LIB_EC, EC_R_TOO_MANY_RETRIES);
|
||
|
|
goto err;
|
||
|
|
}
|
||
|
|
} else {
|
||
|
|
/* s != 0 => we have a valid signature */
|
||
|
|
break;
|
||
|
|
}
|
||
|
|
} while (1);
|
||
|
|
|
||
|
|
ok = 1;
|
||
|
|
err:
|
||
|
|
if (!ok) {
|
||
|
|
ECDSA_SIG_free(ret);
|
||
|
|
ret = NULL;
|
||
|
|
}
|
||
|
|
BN_CTX_free(ctx);
|
||
|
|
BN_clear_free(m);
|
||
|
|
BN_clear_free(kinv);
|
||
|
|
return ret;
|
||
|
|
}
|
||
|
|
|
||
|
|
/*-
|
||
|
|
* returns
|
||
|
|
* 1: correct signature
|
||
|
|
* 0: incorrect signature
|
||
|
|
* -1: error
|
||
|
|
*/
|
||
|
|
int ossl_ecdsa_verify(int type, const unsigned char *dgst, int dgst_len,
|
||
|
|
const unsigned char *sigbuf, int sig_len, EC_KEY *eckey)
|
||
|
|
{
|
||
|
|
ECDSA_SIG *s;
|
||
|
|
const unsigned char *p = sigbuf;
|
||
|
|
unsigned char *der = NULL;
|
||
|
|
int derlen = -1;
|
||
|
|
int ret = -1;
|
||
|
|
|
||
|
|
s = ECDSA_SIG_new();
|
||
|
|
if (s == NULL)
|
||
|
|
return ret;
|
||
|
|
if (d2i_ECDSA_SIG(&s, &p, sig_len) == NULL)
|
||
|
|
goto err;
|
||
|
|
/* Ensure signature uses DER and doesn't have trailing garbage */
|
||
|
|
derlen = i2d_ECDSA_SIG(s, &der);
|
||
|
|
if (derlen != sig_len || memcmp(sigbuf, der, derlen) != 0)
|
||
|
|
goto err;
|
||
|
|
ret = ECDSA_do_verify(dgst, dgst_len, s, eckey);
|
||
|
|
err:
|
||
|
|
OPENSSL_free(der);
|
||
|
|
ECDSA_SIG_free(s);
|
||
|
|
return ret;
|
||
|
|
}
|
||
|
|
|
||
|
|
int ossl_ecdsa_simple_verify_sig(const unsigned char *dgst, int dgst_len,
|
||
|
|
const ECDSA_SIG *sig, EC_KEY *eckey)
|
||
|
|
{
|
||
|
|
int ret = -1, i;
|
||
|
|
BN_CTX *ctx;
|
||
|
|
const BIGNUM *order;
|
||
|
|
BIGNUM *u1, *u2, *m, *X;
|
||
|
|
EC_POINT *point = NULL;
|
||
|
|
const EC_GROUP *group;
|
||
|
|
const EC_POINT *pub_key;
|
||
|
|
|
||
|
|
/* check input values */
|
||
|
|
if (eckey == NULL || (group = EC_KEY_get0_group(eckey)) == NULL ||
|
||
|
|
(pub_key = EC_KEY_get0_public_key(eckey)) == NULL || sig == NULL) {
|
||
|
|
ERR_raise(ERR_LIB_EC, EC_R_MISSING_PARAMETERS);
|
||
|
|
return -1;
|
||
|
|
}
|
||
|
|
|
||
|
|
if (!EC_KEY_can_sign(eckey)) {
|
||
|
|
ERR_raise(ERR_LIB_EC, EC_R_CURVE_DOES_NOT_SUPPORT_SIGNING);
|
||
|
|
return -1;
|
||
|
|
}
|
||
|
|
|
||
|
|
ctx = BN_CTX_new_ex(eckey->libctx);
|
||
|
|
if (ctx == NULL) {
|
||
|
|
ERR_raise(ERR_LIB_EC, ERR_R_BN_LIB);
|
||
|
|
return -1;
|
||
|
|
}
|
||
|
|
BN_CTX_start(ctx);
|
||
|
|
u1 = BN_CTX_get(ctx);
|
||
|
|
u2 = BN_CTX_get(ctx);
|
||
|
|
m = BN_CTX_get(ctx);
|
||
|
|
X = BN_CTX_get(ctx);
|
||
|
|
if (X == NULL) {
|
||
|
|
ERR_raise(ERR_LIB_EC, ERR_R_BN_LIB);
|
||
|
|
goto err;
|
||
|
|
}
|
||
|
|
|
||
|
|
order = EC_GROUP_get0_order(group);
|
||
|
|
if (order == NULL) {
|
||
|
|
ERR_raise(ERR_LIB_EC, ERR_R_EC_LIB);
|
||
|
|
goto err;
|
||
|
|
}
|
||
|
|
|
||
|
|
if (BN_is_zero(sig->r) || BN_is_negative(sig->r) ||
|
||
|
|
BN_ucmp(sig->r, order) >= 0 || BN_is_zero(sig->s) ||
|
||
|
|
BN_is_negative(sig->s) || BN_ucmp(sig->s, order) >= 0) {
|
||
|
|
ERR_raise(ERR_LIB_EC, EC_R_BAD_SIGNATURE);
|
||
|
|
ret = 0; /* signature is invalid */
|
||
|
|
goto err;
|
||
|
|
}
|
||
|
|
/* calculate tmp1 = inv(S) mod order */
|
||
|
|
if (!ossl_ec_group_do_inverse_ord(group, u2, sig->s, ctx)) {
|
||
|
|
ERR_raise(ERR_LIB_EC, ERR_R_BN_LIB);
|
||
|
|
goto err;
|
||
|
|
}
|
||
|
|
/* digest -> m */
|
||
|
|
i = BN_num_bits(order);
|
||
|
|
/*
|
||
|
|
* Need to truncate digest if it is too long: first truncate whole bytes.
|
||
|
|
*/
|
||
|
|
if (8 * dgst_len > i)
|
||
|
|
dgst_len = (i + 7) / 8;
|
||
|
|
if (!BN_bin2bn(dgst, dgst_len, m)) {
|
||
|
|
ERR_raise(ERR_LIB_EC, ERR_R_BN_LIB);
|
||
|
|
goto err;
|
||
|
|
}
|
||
|
|
/* If still too long truncate remaining bits with a shift */
|
||
|
|
if ((8 * dgst_len > i) && !BN_rshift(m, m, 8 - (i & 0x7))) {
|
||
|
|
ERR_raise(ERR_LIB_EC, ERR_R_BN_LIB);
|
||
|
|
goto err;
|
||
|
|
}
|
||
|
|
/* u1 = m * tmp mod order */
|
||
|
|
if (!BN_mod_mul(u1, m, u2, order, ctx)) {
|
||
|
|
ERR_raise(ERR_LIB_EC, ERR_R_BN_LIB);
|
||
|
|
goto err;
|
||
|
|
}
|
||
|
|
/* u2 = r * w mod q */
|
||
|
|
if (!BN_mod_mul(u2, sig->r, u2, order, ctx)) {
|
||
|
|
ERR_raise(ERR_LIB_EC, ERR_R_BN_LIB);
|
||
|
|
goto err;
|
||
|
|
}
|
||
|
|
|
||
|
|
if ((point = EC_POINT_new(group)) == NULL) {
|
||
|
|
ERR_raise(ERR_LIB_EC, ERR_R_EC_LIB);
|
||
|
|
goto err;
|
||
|
|
}
|
||
|
|
if (!EC_POINT_mul(group, point, u1, pub_key, u2, ctx)) {
|
||
|
|
ERR_raise(ERR_LIB_EC, ERR_R_EC_LIB);
|
||
|
|
goto err;
|
||
|
|
}
|
||
|
|
|
||
|
|
if (!EC_POINT_get_affine_coordinates(group, point, X, NULL, ctx)) {
|
||
|
|
ERR_raise(ERR_LIB_EC, ERR_R_EC_LIB);
|
||
|
|
goto err;
|
||
|
|
}
|
||
|
|
|
||
|
|
if (!BN_nnmod(u1, X, order, ctx)) {
|
||
|
|
ERR_raise(ERR_LIB_EC, ERR_R_BN_LIB);
|
||
|
|
goto err;
|
||
|
|
}
|
||
|
|
/* if the signature is correct u1 is equal to sig->r */
|
||
|
|
ret = (BN_ucmp(u1, sig->r) == 0);
|
||
|
|
err:
|
||
|
|
BN_CTX_end(ctx);
|
||
|
|
BN_CTX_free(ctx);
|
||
|
|
EC_POINT_free(point);
|
||
|
|
return ret;
|
||
|
|
}
|