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- /* ====================================================================
- * Copyright (c) 1998-2005 The OpenSSL Project. All rights reserved.
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions
- * are met:
- *
- * 1. Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *
- * 2. Redistributions in binary form must reproduce the above copyright
- * notice, this list of conditions and the following disclaimer in
- * the documentation and/or other materials provided with the
- * distribution.
- *
- * 3. All advertising materials mentioning features or use of this
- * software must display the following acknowledgment:
- * "This product includes software developed by the OpenSSL Project
- * for use in the OpenSSL Toolkit. (http://www.OpenSSL.org/)"
- *
- * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
- * endorse or promote products derived from this software without
- * prior written permission. For written permission, please contact
- * openssl-core@OpenSSL.org.
- *
- * 5. Products derived from this software may not be called "OpenSSL"
- * nor may "OpenSSL" appear in their names without prior written
- * permission of the OpenSSL Project.
- *
- * 6. Redistributions of any form whatsoever must retain the following
- * acknowledgment:
- * "This product includes software developed by the OpenSSL Project
- * for use in the OpenSSL Toolkit (http://www.OpenSSL.org/)"
- *
- * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
- * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
- * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
- * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR
- * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
- * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
- * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
- * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
- * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
- * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
- * OF THE POSSIBILITY OF SUCH DAMAGE.
- * ====================================================================
- *
- * This product includes cryptographic software written by Eric Young
- * (eay@cryptsoft.com). This product includes software written by Tim
- * Hudson (tjh@cryptsoft.com). */
-
- #include <openssl/ecdsa.h>
-
- #include <assert.h>
- #include <string.h>
-
- #include <openssl/bn.h>
- #include <openssl/bytestring.h>
- #include <openssl/err.h>
- #include <openssl/mem.h>
-
- #include "../ec/internal.h"
-
-
- int ECDSA_sign(int type, const uint8_t *digest, size_t digest_len, uint8_t *sig,
- unsigned int *sig_len, EC_KEY *eckey) {
- if (eckey->ecdsa_meth && eckey->ecdsa_meth->sign) {
- return eckey->ecdsa_meth->sign(digest, digest_len, sig, sig_len, eckey);
- }
-
- return ECDSA_sign_ex(type, digest, digest_len, sig, sig_len, NULL, NULL,
- eckey);
- }
-
- int ECDSA_verify(int type, const uint8_t *digest, size_t digest_len,
- const uint8_t *sig, size_t sig_len, EC_KEY *eckey) {
- ECDSA_SIG *s;
- int ret = 0;
- uint8_t *der = NULL;
-
- if (eckey->ecdsa_meth && eckey->ecdsa_meth->verify) {
- return eckey->ecdsa_meth->verify(digest, digest_len, sig, sig_len, eckey);
- }
-
- /* Decode the ECDSA signature. */
- s = ECDSA_SIG_from_bytes(sig, sig_len);
- if (s == NULL) {
- goto err;
- }
-
- /* Defend against potential laxness in the DER parser. */
- size_t der_len;
- if (!ECDSA_SIG_to_bytes(&der, &der_len, s) ||
- der_len != sig_len || memcmp(sig, der, sig_len) != 0) {
- /* This should never happen. crypto/bytestring is strictly DER. */
- OPENSSL_PUT_ERROR(ECDSA, ERR_R_INTERNAL_ERROR);
- goto err;
- }
-
- ret = ECDSA_do_verify(digest, digest_len, s, eckey);
-
- err:
- OPENSSL_free(der);
- ECDSA_SIG_free(s);
- return ret;
- }
-
- /* digest_to_bn interprets |digest_len| bytes from |digest| as a big-endian
- * number and sets |out| to that value. It then truncates |out| so that it's,
- * at most, as long as |order|. It returns one on success and zero otherwise. */
- static int digest_to_bn(BIGNUM *out, const uint8_t *digest, size_t digest_len,
- const BIGNUM *order) {
- size_t num_bits;
-
- num_bits = BN_num_bits(order);
- /* Need to truncate digest if it is too long: first truncate whole
- * bytes. */
- if (8 * digest_len > num_bits) {
- digest_len = (num_bits + 7) / 8;
- }
- if (!BN_bin2bn(digest, digest_len, out)) {
- OPENSSL_PUT_ERROR(ECDSA, ERR_R_BN_LIB);
- return 0;
- }
-
- /* If still too long truncate remaining bits with a shift */
- if ((8 * digest_len > num_bits) &&
- !BN_rshift(out, out, 8 - (num_bits & 0x7))) {
- OPENSSL_PUT_ERROR(ECDSA, ERR_R_BN_LIB);
- return 0;
- }
-
- return 1;
- }
-
- ECDSA_SIG *ECDSA_do_sign(const uint8_t *digest, size_t digest_len,
- EC_KEY *key) {
- return ECDSA_do_sign_ex(digest, digest_len, NULL, NULL, key);
- }
-
- int ECDSA_do_verify(const uint8_t *digest, size_t digest_len,
- const ECDSA_SIG *sig, EC_KEY *eckey) {
- int ret = 0;
- BN_CTX *ctx;
- BIGNUM *order, *u1, *u2, *m, *X;
- EC_POINT *point = NULL;
- const EC_GROUP *group;
- const EC_POINT *pub_key;
-
- if (eckey->ecdsa_meth && eckey->ecdsa_meth->verify) {
- OPENSSL_PUT_ERROR(ECDSA, ECDSA_R_NOT_IMPLEMENTED);
- return 0;
- }
-
- /* check input values */
- if ((group = EC_KEY_get0_group(eckey)) == NULL ||
- (pub_key = EC_KEY_get0_public_key(eckey)) == NULL ||
- sig == NULL) {
- OPENSSL_PUT_ERROR(ECDSA, ECDSA_R_MISSING_PARAMETERS);
- return 0;
- }
-
- ctx = BN_CTX_new();
- if (!ctx) {
- OPENSSL_PUT_ERROR(ECDSA, ERR_R_MALLOC_FAILURE);
- return 0;
- }
- BN_CTX_start(ctx);
- order = BN_CTX_get(ctx);
- u1 = BN_CTX_get(ctx);
- u2 = BN_CTX_get(ctx);
- m = BN_CTX_get(ctx);
- X = BN_CTX_get(ctx);
- if (!X) {
- OPENSSL_PUT_ERROR(ECDSA, ERR_R_BN_LIB);
- goto err;
- }
-
- if (!EC_GROUP_get_order(group, order, ctx)) {
- OPENSSL_PUT_ERROR(ECDSA, 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) {
- OPENSSL_PUT_ERROR(ECDSA, ECDSA_R_BAD_SIGNATURE);
- ret = 0; /* signature is invalid */
- goto err;
- }
- /* calculate tmp1 = inv(S) mod order */
- if (!BN_mod_inverse(u2, sig->s, order, ctx)) {
- OPENSSL_PUT_ERROR(ECDSA, ERR_R_BN_LIB);
- goto err;
- }
- if (!digest_to_bn(m, digest, digest_len, order)) {
- goto err;
- }
- /* u1 = m * tmp mod order */
- if (!BN_mod_mul(u1, m, u2, order, ctx)) {
- OPENSSL_PUT_ERROR(ECDSA, ERR_R_BN_LIB);
- goto err;
- }
- /* u2 = r * w mod q */
- if (!BN_mod_mul(u2, sig->r, u2, order, ctx)) {
- OPENSSL_PUT_ERROR(ECDSA, ERR_R_BN_LIB);
- goto err;
- }
-
- point = EC_POINT_new(group);
- if (point == NULL) {
- OPENSSL_PUT_ERROR(ECDSA, ERR_R_MALLOC_FAILURE);
- goto err;
- }
- if (!EC_POINT_mul(group, point, u1, pub_key, u2, ctx)) {
- OPENSSL_PUT_ERROR(ECDSA, ERR_R_EC_LIB);
- goto err;
- }
- if (!EC_POINT_get_affine_coordinates_GFp(group, point, X, NULL, ctx)) {
- OPENSSL_PUT_ERROR(ECDSA, ERR_R_EC_LIB);
- goto err;
- }
- if (!BN_nnmod(u1, X, order, ctx)) {
- OPENSSL_PUT_ERROR(ECDSA, 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;
- }
-
- static int ecdsa_sign_setup(EC_KEY *eckey, BN_CTX *ctx_in, BIGNUM **kinvp,
- BIGNUM **rp, const uint8_t *digest,
- size_t digest_len) {
- BN_CTX *ctx = NULL;
- BIGNUM *k = NULL, *r = NULL, *order = NULL, *X = NULL;
- EC_POINT *tmp_point = NULL;
- const EC_GROUP *group;
- int ret = 0;
-
- if (eckey == NULL || (group = EC_KEY_get0_group(eckey)) == NULL) {
- OPENSSL_PUT_ERROR(ECDSA, ERR_R_PASSED_NULL_PARAMETER);
- return 0;
- }
-
- if (ctx_in == NULL) {
- if ((ctx = BN_CTX_new()) == NULL) {
- OPENSSL_PUT_ERROR(ECDSA, 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 */
- order = BN_new();
- X = BN_new();
- if (!k || !r || !order || !X) {
- OPENSSL_PUT_ERROR(ECDSA, ERR_R_MALLOC_FAILURE);
- goto err;
- }
- tmp_point = EC_POINT_new(group);
- if (tmp_point == NULL) {
- OPENSSL_PUT_ERROR(ECDSA, ERR_R_EC_LIB);
- goto err;
- }
- if (!EC_GROUP_get_order(group, order, ctx)) {
- OPENSSL_PUT_ERROR(ECDSA, ERR_R_EC_LIB);
- goto err;
- }
-
- do {
- /* If possible, we'll include the private key and message digest in the k
- * generation. The |digest| argument is only empty if |ECDSA_sign_setup| is
- * being used. */
- do {
- int ok;
-
- if (digest_len > 0) {
- ok = BN_generate_dsa_nonce(k, order, EC_KEY_get0_private_key(eckey),
- digest, digest_len, ctx);
- } else {
- ok = BN_rand_range(k, order);
- }
- if (!ok) {
- OPENSSL_PUT_ERROR(ECDSA, ECDSA_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;
- }
- }
-
- /* compute r the x-coordinate of generator * k */
- if (!EC_POINT_mul(group, tmp_point, k, NULL, NULL, ctx)) {
- OPENSSL_PUT_ERROR(ECDSA, ERR_R_EC_LIB);
- goto err;
- }
- if (!EC_POINT_get_affine_coordinates_GFp(group, tmp_point, X, NULL, ctx)) {
- OPENSSL_PUT_ERROR(ECDSA, ERR_R_EC_LIB);
- goto err;
- }
-
- if (!BN_nnmod(r, X, order, ctx)) {
- OPENSSL_PUT_ERROR(ECDSA, ERR_R_BN_LIB);
- goto err;
- }
- } while (BN_is_zero(r));
-
- /* compute the inverse of k */
- if (!BN_mod_inverse(k, k, order, ctx)) {
- OPENSSL_PUT_ERROR(ECDSA, 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_in == NULL) {
- BN_CTX_free(ctx);
- }
- BN_free(order);
- EC_POINT_free(tmp_point);
- BN_clear_free(X);
- return ret;
- }
-
- int ECDSA_sign_setup(EC_KEY *eckey, BN_CTX *ctx, BIGNUM **kinv, BIGNUM **rp) {
- return ecdsa_sign_setup(eckey, ctx, kinv, rp, NULL, 0);
- }
-
- ECDSA_SIG *ECDSA_do_sign_ex(const uint8_t *digest, size_t digest_len,
- const BIGNUM *in_kinv, const BIGNUM *in_r,
- EC_KEY *eckey) {
- int ok = 0;
- BIGNUM *kinv = NULL, *s, *m = NULL, *tmp = NULL, *order = NULL;
- const BIGNUM *ckinv;
- BN_CTX *ctx = NULL;
- const EC_GROUP *group;
- ECDSA_SIG *ret;
- const BIGNUM *priv_key;
-
- if (eckey->ecdsa_meth && eckey->ecdsa_meth->sign) {
- OPENSSL_PUT_ERROR(ECDSA, ECDSA_R_NOT_IMPLEMENTED);
- return NULL;
- }
-
- group = EC_KEY_get0_group(eckey);
- priv_key = EC_KEY_get0_private_key(eckey);
-
- if (group == NULL || priv_key == NULL) {
- OPENSSL_PUT_ERROR(ECDSA, ERR_R_PASSED_NULL_PARAMETER);
- return NULL;
- }
-
- ret = ECDSA_SIG_new();
- if (!ret) {
- OPENSSL_PUT_ERROR(ECDSA, ERR_R_MALLOC_FAILURE);
- return NULL;
- }
- s = ret->s;
-
- if ((ctx = BN_CTX_new()) == NULL || (order = BN_new()) == NULL ||
- (tmp = BN_new()) == NULL || (m = BN_new()) == NULL) {
- OPENSSL_PUT_ERROR(ECDSA, ERR_R_MALLOC_FAILURE);
- goto err;
- }
-
- if (!EC_GROUP_get_order(group, order, ctx)) {
- OPENSSL_PUT_ERROR(ECDSA, ERR_R_EC_LIB);
- goto err;
- }
- if (!digest_to_bn(m, digest, digest_len, order)) {
- goto err;
- }
- for (;;) {
- if (in_kinv == NULL || in_r == NULL) {
- if (!ecdsa_sign_setup(eckey, ctx, &kinv, &ret->r, digest, digest_len)) {
- OPENSSL_PUT_ERROR(ECDSA, ERR_R_ECDSA_LIB);
- goto err;
- }
- ckinv = kinv;
- } else {
- ckinv = in_kinv;
- if (BN_copy(ret->r, in_r) == NULL) {
- OPENSSL_PUT_ERROR(ECDSA, ERR_R_MALLOC_FAILURE);
- goto err;
- }
- }
-
- if (!BN_mod_mul(tmp, priv_key, ret->r, order, ctx)) {
- OPENSSL_PUT_ERROR(ECDSA, ERR_R_BN_LIB);
- goto err;
- }
- if (!BN_mod_add_quick(s, tmp, m, order)) {
- OPENSSL_PUT_ERROR(ECDSA, ERR_R_BN_LIB);
- goto err;
- }
- if (!BN_mod_mul(s, s, ckinv, order, ctx)) {
- OPENSSL_PUT_ERROR(ECDSA, ERR_R_BN_LIB);
- goto err;
- }
- if (BN_is_zero(s)) {
- /* if kinv and r have been supplied by the caller
- * don't to generate new kinv and r values */
- if (in_kinv != NULL && in_r != NULL) {
- OPENSSL_PUT_ERROR(ECDSA, ECDSA_R_NEED_NEW_SETUP_VALUES);
- goto err;
- }
- } else {
- /* s != 0 => we have a valid signature */
- break;
- }
- }
-
- ok = 1;
-
- err:
- if (!ok) {
- ECDSA_SIG_free(ret);
- ret = NULL;
- }
- BN_CTX_free(ctx);
- BN_clear_free(m);
- BN_clear_free(tmp);
- BN_free(order);
- BN_clear_free(kinv);
- return ret;
- }
-
- int ECDSA_sign_ex(int type, const uint8_t *digest, size_t digest_len,
- uint8_t *sig, unsigned int *sig_len, const BIGNUM *kinv,
- const BIGNUM *r, EC_KEY *eckey) {
- int ret = 0;
- ECDSA_SIG *s = NULL;
-
- if (eckey->ecdsa_meth && eckey->ecdsa_meth->sign) {
- OPENSSL_PUT_ERROR(ECDSA, ECDSA_R_NOT_IMPLEMENTED);
- *sig_len = 0;
- goto err;
- }
-
- s = ECDSA_do_sign_ex(digest, digest_len, kinv, r, eckey);
- if (s == NULL) {
- *sig_len = 0;
- goto err;
- }
-
- CBB cbb;
- CBB_zero(&cbb);
- size_t len;
- if (!CBB_init_fixed(&cbb, sig, ECDSA_size(eckey)) ||
- !ECDSA_SIG_marshal(&cbb, s) ||
- !CBB_finish(&cbb, NULL, &len)) {
- OPENSSL_PUT_ERROR(ECDSA, ECDSA_R_ENCODE_ERROR);
- CBB_cleanup(&cbb);
- *sig_len = 0;
- goto err;
- }
- *sig_len = (unsigned)len;
- ret = 1;
-
- err:
- ECDSA_SIG_free(s);
- return ret;
- }
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