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- /*
- * Copyright 2002-2021 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"
- 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);
- ECDSA_SIG_free(s);
- return 1;
- }
- static int ecdsa_sign_setup(EC_KEY *eckey, BN_CTX *ctx_in,
- BIGNUM **kinvp, BIGNUM **rp,
- const unsigned char *dgst, int dlen)
- {
- 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_MALLOC_FAILURE);
- 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_MALLOC_FAILURE);
- 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);
- 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 {
- if (dgst != NULL) {
- if (!BN_generate_dsa_nonce(k, order, priv_key,
- dgst, dlen, ctx)) {
- ERR_raise(ERR_LIB_EC, EC_R_RANDOM_NUMBER_GENERATION_FAILED);
- goto err;
- }
- } else {
- if (!BN_priv_rand_range_ex(k, order, 0, ctx)) {
- 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);
- }
- 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;
- 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_MALLOC_FAILURE);
- return NULL;
- }
- ret->r = BN_new();
- ret->s = BN_new();
- if (ret->r == NULL || ret->s == NULL) {
- ERR_raise(ERR_LIB_EC, ERR_R_MALLOC_FAILURE);
- 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_MALLOC_FAILURE);
- 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)) {
- 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_MALLOC_FAILURE);
- 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;
- }
- } 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_MALLOC_FAILURE);
- 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_MALLOC_FAILURE);
- 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;
- }
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