/*
- * Copyright 2002-2016 The OpenSSL Project Authors. All Rights Reserved.
+ * Copyright 2002-2018 The OpenSSL Project Authors. 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
#include <string.h>
#include <openssl/err.h>
#include <openssl/obj_mac.h>
-#include <openssl/bn.h>
#include <openssl/rand.h>
-#include <openssl/ec.h>
+#include "internal/bn_int.h"
#include "ec_lcl.h"
int ossl_ecdsa_sign(int type, const unsigned char *dgst, int dlen,
const BIGNUM *kinv, const BIGNUM *r, EC_KEY *eckey)
{
ECDSA_SIG *s;
- RAND_seed(dgst, dlen);
+
s = ECDSA_do_sign_ex(dgst, dlen, kinv, r, eckey);
if (s == NULL) {
*siglen = 0;
EC_POINT *tmp_point = NULL;
const EC_GROUP *group;
int ret = 0;
+ int order_bits;
if (eckey == NULL || (group = EC_KEY_get0_group(eckey)) == NULL) {
ECerr(EC_F_ECDSA_SIGN_SETUP, ERR_R_PASSED_NULL_PARAMETER);
return 0;
}
- if (ctx_in == NULL) {
+ if ((ctx = ctx_in) == NULL) {
if ((ctx = BN_CTX_new()) == NULL) {
ECerr(EC_F_ECDSA_SIGN_SETUP, ERR_R_MALLOC_FAILURE);
return 0;
}
- } else
- ctx = ctx_in;
+ }
k = BN_new(); /* this value is later returned in *kinvp */
r = BN_new(); /* this value is later returned in *rp */
goto err;
}
order = EC_GROUP_get0_order(group);
- if (order == NULL) {
- ECerr(EC_F_ECDSA_SIGN_SETUP, ERR_R_EC_LIB);
+
+ /* Preallocate space */
+ order_bits = BN_num_bits(order);
+ if (!BN_set_bit(k, order_bits)
+ || !BN_set_bit(r, order_bits)
+ || !BN_set_bit(X, order_bits))
goto err;
- }
do {
/* get random k */
- do
+ do {
if (dgst != NULL) {
- if (!BN_generate_dsa_nonce
- (k, order, EC_KEY_get0_private_key(eckey), dgst, dlen,
- ctx)) {
+ if (!BN_generate_dsa_nonce(k, order,
+ EC_KEY_get0_private_key(eckey),
+ dgst, dlen, ctx)) {
ECerr(EC_F_ECDSA_SIGN_SETUP,
- EC_R_RANDOM_NUMBER_GENERATION_FAILED);
+ EC_R_RANDOM_NUMBER_GENERATION_FAILED);
goto err;
}
} else {
- if (!BN_rand_range(k, order)) {
+ if (!BN_priv_rand_range(k, order)) {
ECerr(EC_F_ECDSA_SIGN_SETUP,
- EC_R_RANDOM_NUMBER_GENERATION_FAILED);
+ EC_R_RANDOM_NUMBER_GENERATION_FAILED);
goto err;
}
}
- while (BN_is_zero(k));
-
- /*
- * We do not want timing information to leak the length of k, so we
- * compute G*k using an equivalent scalar of fixed bit-length.
- */
-
- if (!BN_add(k, k, order))
- goto err;
- if (BN_num_bits(k) <= BN_num_bits(order))
- if (!BN_add(k, k, order))
- 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)) {
ECerr(EC_F_ECDSA_SIGN_SETUP, ERR_R_EC_LIB);
goto err;
}
- if (EC_METHOD_get_field_type(EC_GROUP_method_of(group)) ==
- NID_X9_62_prime_field) {
- if (!EC_POINT_get_affine_coordinates_GFp
- (group, tmp_point, X, NULL, ctx)) {
- ECerr(EC_F_ECDSA_SIGN_SETUP, ERR_R_EC_LIB);
- goto err;
- }
- }
-#ifndef OPENSSL_NO_EC2M
- else { /* NID_X9_62_characteristic_two_field */
- if (!EC_POINT_get_affine_coordinates_GF2m(group,
- tmp_point, X, NULL,
- ctx)) {
- ECerr(EC_F_ECDSA_SIGN_SETUP, ERR_R_EC_LIB);
- goto err;
- }
+ if (!EC_POINT_get_affine_coordinates(group, tmp_point, X, NULL, ctx)) {
+ ECerr(EC_F_ECDSA_SIGN_SETUP, ERR_R_EC_LIB);
+ goto err;
}
-#endif
+
if (!BN_nnmod(r, X, order, ctx)) {
ECerr(EC_F_ECDSA_SIGN_SETUP, ERR_R_BN_LIB);
goto err;
}
- }
- while (BN_is_zero(r));
+ } while (BN_is_zero(r));
/* compute the inverse of k */
- if (EC_GROUP_get_mont_data(group) != NULL) {
- /*
- * 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(X, 2)) {
- ECerr(EC_F_ECDSA_SIGN_SETUP, ERR_R_BN_LIB);
- goto err;
- }
- if (!BN_mod_sub(X, order, X, order, ctx)) {
- ECerr(EC_F_ECDSA_SIGN_SETUP, ERR_R_BN_LIB);
- goto err;
- }
- BN_set_flags(X, BN_FLG_CONSTTIME);
- if (!BN_mod_exp_mont_consttime
- (k, k, X, order, ctx, EC_GROUP_get_mont_data(group))) {
- ECerr(EC_F_ECDSA_SIGN_SETUP, ERR_R_BN_LIB);
- goto err;
- }
- } else {
- if (!BN_mod_inverse(k, k, order, ctx)) {
- ECerr(EC_F_ECDSA_SIGN_SETUP, ERR_R_BN_LIB);
- goto err;
- }
+ if (!ec_group_do_inverse_ord(group, k, k, ctx)) {
+ ECerr(EC_F_ECDSA_SIGN_SETUP, ERR_R_BN_LIB);
+ goto err;
}
/* clear old values if necessary */
BN_CTX_free(ctx);
EC_POINT_free(tmp_point);
BN_clear_free(X);
- return (ret);
+ return ret;
}
int ossl_ecdsa_sign_setup(EC_KEY *eckey, BN_CTX *ctx_in, BIGNUM **kinvp,
EC_KEY *eckey)
{
int ok = 0, i;
- BIGNUM *kinv = NULL, *s, *m = NULL, *tmp = NULL;
+ BIGNUM *kinv = NULL, *s, *m = NULL;
const BIGNUM *order, *ckinv;
BN_CTX *ctx = NULL;
const EC_GROUP *group;
ECerr(EC_F_OSSL_ECDSA_SIGN_SIG, ERR_R_MALLOC_FAILURE);
return NULL;
}
+ ret->r = BN_new();
+ ret->s = BN_new();
+ if (ret->r == NULL || ret->s == NULL) {
+ ECerr(EC_F_OSSL_ECDSA_SIGN_SIG, ERR_R_MALLOC_FAILURE);
+ goto err;
+ }
s = ret->s;
- if ((ctx = BN_CTX_new()) == NULL ||
- (tmp = BN_new()) == NULL || (m = BN_new()) == NULL) {
+ if ((ctx = BN_CTX_new()) == NULL
+ || (m = BN_new()) == NULL) {
ECerr(EC_F_OSSL_ECDSA_SIGN_SIG, ERR_R_MALLOC_FAILURE);
goto err;
}
order = EC_GROUP_get0_order(group);
- if (order == NULL) {
- ECerr(EC_F_OSSL_ECDSA_SIGN_SIG, ERR_R_EC_LIB);
- goto err;
- }
i = BN_num_bits(order);
/*
* Need to truncate digest if it is too long: first truncate whole bytes.
ECerr(EC_F_OSSL_ECDSA_SIGN_SIG, ERR_R_BN_LIB);
goto err;
}
- /* If still too long truncate remaining bits with a shift */
+ /* If still too long, truncate remaining bits with a shift */
if ((8 * dgst_len > i) && !BN_rshift(m, m, 8 - (i & 0x7))) {
ECerr(EC_F_OSSL_ECDSA_SIGN_SIG, ERR_R_BN_LIB);
goto err;
}
}
- if (!BN_mod_mul(tmp, priv_key, ret->r, order, ctx)) {
+ /*
+ * 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)) {
ECerr(EC_F_OSSL_ECDSA_SIGN_SIG, ERR_R_BN_LIB);
goto err;
}
- if (!BN_mod_add_quick(s, tmp, m, order)) {
+ if (!bn_mod_add_fixed_top(s, s, m, order)) {
ECerr(EC_F_OSSL_ECDSA_SIGN_SIG, ERR_R_BN_LIB);
goto err;
}
- if (!BN_mod_mul(s, s, ckinv, order, ctx)) {
+ /*
+ * |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)) {
ECerr(EC_F_OSSL_ECDSA_SIGN_SIG, ERR_R_BN_LIB);
goto err;
}
+
if (BN_is_zero(s)) {
/*
- * if kinv and r have been supplied by the caller don't to
+ * 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) {
ECerr(EC_F_OSSL_ECDSA_SIGN_SIG, EC_R_NEED_NEW_SETUP_VALUES);
goto err;
}
- } else
+ } else {
/* s != 0 => we have a valid signature */
break;
- }
- while (1);
+ }
+ } while (1);
ok = 1;
err:
}
BN_CTX_free(ctx);
BN_clear_free(m);
- BN_clear_free(tmp);
BN_clear_free(kinv);
return ret;
}
s = ECDSA_SIG_new();
if (s == NULL)
- return (ret);
+ return ret;
if (d2i_ECDSA_SIG(&s, &p, sig_len) == NULL)
goto err;
/* Ensure signature uses DER and doesn't have trailing garbage */
err:
OPENSSL_clear_free(der, derlen);
ECDSA_SIG_free(s);
- return (ret);
+ return ret;
}
int ossl_ecdsa_verify_sig(const unsigned char *dgst, int dgst_len,
goto err;
}
/* calculate tmp1 = inv(S) mod order */
- if (!BN_mod_inverse(u2, sig->s, order, ctx)) {
+ if (!ec_group_do_inverse_ord(group, u2, sig->s, ctx)) {
ECerr(EC_F_OSSL_ECDSA_VERIFY_SIG, ERR_R_BN_LIB);
goto err;
}
ECerr(EC_F_OSSL_ECDSA_VERIFY_SIG, ERR_R_EC_LIB);
goto err;
}
- if (EC_METHOD_get_field_type(EC_GROUP_method_of(group)) ==
- NID_X9_62_prime_field) {
- if (!EC_POINT_get_affine_coordinates_GFp(group, point, X, NULL, ctx)) {
- ECerr(EC_F_OSSL_ECDSA_VERIFY_SIG, ERR_R_EC_LIB);
- goto err;
- }
- }
-#ifndef OPENSSL_NO_EC2M
- else { /* NID_X9_62_characteristic_two_field */
- if (!EC_POINT_get_affine_coordinates_GF2m(group, point, X, NULL, ctx)) {
- ECerr(EC_F_OSSL_ECDSA_VERIFY_SIG, ERR_R_EC_LIB);
- goto err;
- }
+ if (!EC_POINT_get_affine_coordinates(group, point, X, NULL, ctx)) {
+ ECerr(EC_F_OSSL_ECDSA_VERIFY_SIG, ERR_R_EC_LIB);
+ goto err;
}
-#endif
+
if (!BN_nnmod(u1, X, order, ctx)) {
ECerr(EC_F_OSSL_ECDSA_VERIFY_SIG, ERR_R_BN_LIB);
goto err;
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