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442 lines
14 KiB
442 lines
14 KiB
/* crypto/ecdsa/ecs_ossl.c */ |
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/* |
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* Written by Nils Larsch for the OpenSSL project |
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*/ |
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/* ==================================================================== |
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* Copyright (c) 1998-2004 The OpenSSL Project. All rights reserved. |
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* |
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* Redistribution and use in source and binary forms, with or without |
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* modification, are permitted provided that the following conditions |
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* are met: |
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* |
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* 1. Redistributions of source code must retain the above copyright |
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* notice, this list of conditions and the following disclaimer. |
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* |
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* 2. Redistributions in binary form must reproduce the above copyright |
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* notice, this list of conditions and the following disclaimer in |
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* the documentation and/or other materials provided with the |
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* distribution. |
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* |
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* 3. All advertising materials mentioning features or use of this |
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* software must display the following acknowledgment: |
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* "This product includes software developed by the OpenSSL Project |
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* for use in the OpenSSL Toolkit. (http://www.OpenSSL.org/)" |
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* |
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* 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to |
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* endorse or promote products derived from this software without |
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* prior written permission. For written permission, please contact |
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* openssl-core@OpenSSL.org. |
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* |
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* 5. Products derived from this software may not be called "OpenSSL" |
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* nor may "OpenSSL" appear in their names without prior written |
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* permission of the OpenSSL Project. |
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* |
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* 6. Redistributions of any form whatsoever must retain the following |
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* acknowledgment: |
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* "This product includes software developed by the OpenSSL Project |
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* for use in the OpenSSL Toolkit (http://www.OpenSSL.org/)" |
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* |
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* THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY |
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* EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR |
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* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR |
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* ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, |
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* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT |
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; |
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* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) |
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, |
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* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) |
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED |
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* OF THE POSSIBILITY OF SUCH DAMAGE. |
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* ==================================================================== |
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* |
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* This product includes cryptographic software written by Eric Young |
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* (eay@cryptsoft.com). This product includes software written by Tim |
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* Hudson (tjh@cryptsoft.com). |
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* |
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*/ |
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#include "ecs_locl.h" |
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#include <openssl/err.h> |
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#include <openssl/obj_mac.h> |
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#include <openssl/bn.h> |
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static ECDSA_SIG *ecdsa_do_sign(const unsigned char *dgst, int dlen, |
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const BIGNUM *, const BIGNUM *, |
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EC_KEY *eckey); |
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static int ecdsa_sign_setup(EC_KEY *eckey, BN_CTX *ctx_in, BIGNUM **kinvp, |
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BIGNUM **rp); |
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static int ecdsa_do_verify(const unsigned char *dgst, int dgst_len, |
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const ECDSA_SIG *sig, EC_KEY *eckey); |
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static ECDSA_METHOD openssl_ecdsa_meth = { |
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"OpenSSL ECDSA method", |
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ecdsa_do_sign, |
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ecdsa_sign_setup, |
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ecdsa_do_verify, |
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#if 0 |
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NULL, /* init */ |
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NULL, /* finish */ |
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#endif |
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0, /* flags */ |
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NULL /* app_data */ |
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}; |
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const ECDSA_METHOD *ECDSA_OpenSSL(void) |
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{ |
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return &openssl_ecdsa_meth; |
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} |
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static int ecdsa_sign_setup(EC_KEY *eckey, BN_CTX *ctx_in, BIGNUM **kinvp, |
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BIGNUM **rp) |
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{ |
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BN_CTX *ctx = NULL; |
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BIGNUM *k = NULL, *r = NULL, *order = NULL, *X = NULL; |
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EC_POINT *tmp_point = NULL; |
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const EC_GROUP *group; |
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int ret = 0; |
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if (eckey == NULL || (group = EC_KEY_get0_group(eckey)) == NULL) { |
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ECDSAerr(ECDSA_F_ECDSA_SIGN_SETUP, ERR_R_PASSED_NULL_PARAMETER); |
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return 0; |
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} |
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if (ctx_in == NULL) { |
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if ((ctx = BN_CTX_new()) == NULL) { |
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ECDSAerr(ECDSA_F_ECDSA_SIGN_SETUP, ERR_R_MALLOC_FAILURE); |
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return 0; |
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} |
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} else |
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ctx = ctx_in; |
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k = BN_new(); /* this value is later returned in *kinvp */ |
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r = BN_new(); /* this value is later returned in *rp */ |
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order = BN_new(); |
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X = BN_new(); |
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if (!k || !r || !order || !X) { |
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ECDSAerr(ECDSA_F_ECDSA_SIGN_SETUP, ERR_R_MALLOC_FAILURE); |
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goto err; |
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} |
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if ((tmp_point = EC_POINT_new(group)) == NULL) { |
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ECDSAerr(ECDSA_F_ECDSA_SIGN_SETUP, ERR_R_EC_LIB); |
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goto err; |
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} |
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if (!EC_GROUP_get_order(group, order, ctx)) { |
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ECDSAerr(ECDSA_F_ECDSA_SIGN_SETUP, ERR_R_EC_LIB); |
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goto err; |
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} |
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do { |
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/* get random k */ |
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do |
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if (!BN_rand_range(k, order)) { |
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ECDSAerr(ECDSA_F_ECDSA_SIGN_SETUP, |
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ECDSA_R_RANDOM_NUMBER_GENERATION_FAILED); |
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goto err; |
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} |
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while (BN_is_zero(k)) ; |
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/* |
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* We do not want timing information to leak the length of k, so we |
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* compute G*k using an equivalent scalar of fixed bit-length. |
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*/ |
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if (!BN_add(k, k, order)) |
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goto err; |
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if (BN_num_bits(k) <= BN_num_bits(order)) |
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if (!BN_add(k, k, order)) |
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goto err; |
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/* compute r the x-coordinate of generator * k */ |
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if (!EC_POINT_mul(group, tmp_point, k, NULL, NULL, ctx)) { |
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ECDSAerr(ECDSA_F_ECDSA_SIGN_SETUP, ERR_R_EC_LIB); |
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goto err; |
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} |
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if (EC_METHOD_get_field_type(EC_GROUP_method_of(group)) == |
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NID_X9_62_prime_field) { |
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if (!EC_POINT_get_affine_coordinates_GFp |
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(group, tmp_point, X, NULL, ctx)) { |
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ECDSAerr(ECDSA_F_ECDSA_SIGN_SETUP, ERR_R_EC_LIB); |
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goto err; |
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} |
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} |
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#ifndef OPENSSL_NO_EC2M |
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else { /* NID_X9_62_characteristic_two_field */ |
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if (!EC_POINT_get_affine_coordinates_GF2m(group, |
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tmp_point, X, NULL, |
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ctx)) { |
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ECDSAerr(ECDSA_F_ECDSA_SIGN_SETUP, ERR_R_EC_LIB); |
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goto err; |
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} |
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} |
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#endif |
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if (!BN_nnmod(r, X, order, ctx)) { |
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ECDSAerr(ECDSA_F_ECDSA_SIGN_SETUP, ERR_R_BN_LIB); |
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goto err; |
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} |
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} |
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while (BN_is_zero(r)); |
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/* compute the inverse of k */ |
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if (!BN_mod_inverse(k, k, order, ctx)) { |
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ECDSAerr(ECDSA_F_ECDSA_SIGN_SETUP, ERR_R_BN_LIB); |
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goto err; |
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} |
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/* clear old values if necessary */ |
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if (*rp != NULL) |
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BN_clear_free(*rp); |
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if (*kinvp != NULL) |
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BN_clear_free(*kinvp); |
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/* save the pre-computed values */ |
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*rp = r; |
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*kinvp = k; |
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ret = 1; |
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err: |
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if (!ret) { |
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if (k != NULL) |
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BN_clear_free(k); |
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if (r != NULL) |
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BN_clear_free(r); |
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} |
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if (ctx_in == NULL) |
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BN_CTX_free(ctx); |
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if (order != NULL) |
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BN_free(order); |
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if (tmp_point != NULL) |
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EC_POINT_free(tmp_point); |
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if (X) |
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BN_clear_free(X); |
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return (ret); |
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} |
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static ECDSA_SIG *ecdsa_do_sign(const unsigned char *dgst, int dgst_len, |
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const BIGNUM *in_kinv, const BIGNUM *in_r, |
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EC_KEY *eckey) |
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{ |
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int ok = 0, i; |
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BIGNUM *kinv = NULL, *s, *m = NULL, *tmp = NULL, *order = NULL; |
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const BIGNUM *ckinv; |
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BN_CTX *ctx = NULL; |
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const EC_GROUP *group; |
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ECDSA_SIG *ret; |
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ECDSA_DATA *ecdsa; |
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const BIGNUM *priv_key; |
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ecdsa = ecdsa_check(eckey); |
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group = EC_KEY_get0_group(eckey); |
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priv_key = EC_KEY_get0_private_key(eckey); |
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if (group == NULL || priv_key == NULL || ecdsa == NULL) { |
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ECDSAerr(ECDSA_F_ECDSA_DO_SIGN, ERR_R_PASSED_NULL_PARAMETER); |
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return NULL; |
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} |
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ret = ECDSA_SIG_new(); |
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if (!ret) { |
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ECDSAerr(ECDSA_F_ECDSA_DO_SIGN, ERR_R_MALLOC_FAILURE); |
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return NULL; |
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} |
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s = ret->s; |
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if ((ctx = BN_CTX_new()) == NULL || (order = BN_new()) == NULL || |
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(tmp = BN_new()) == NULL || (m = BN_new()) == NULL) { |
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ECDSAerr(ECDSA_F_ECDSA_DO_SIGN, ERR_R_MALLOC_FAILURE); |
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goto err; |
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} |
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if (!EC_GROUP_get_order(group, order, ctx)) { |
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ECDSAerr(ECDSA_F_ECDSA_DO_SIGN, ERR_R_EC_LIB); |
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goto err; |
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} |
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i = BN_num_bits(order); |
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/* |
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* Need to truncate digest if it is too long: first truncate whole bytes. |
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*/ |
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if (8 * dgst_len > i) |
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dgst_len = (i + 7) / 8; |
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if (!BN_bin2bn(dgst, dgst_len, m)) { |
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ECDSAerr(ECDSA_F_ECDSA_DO_SIGN, ERR_R_BN_LIB); |
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goto err; |
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} |
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/* If still too long truncate remaining bits with a shift */ |
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if ((8 * dgst_len > i) && !BN_rshift(m, m, 8 - (i & 0x7))) { |
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ECDSAerr(ECDSA_F_ECDSA_DO_SIGN, ERR_R_BN_LIB); |
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goto err; |
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} |
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do { |
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if (in_kinv == NULL || in_r == NULL) { |
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if (!ECDSA_sign_setup(eckey, ctx, &kinv, &ret->r)) { |
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ECDSAerr(ECDSA_F_ECDSA_DO_SIGN, ERR_R_ECDSA_LIB); |
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goto err; |
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} |
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ckinv = kinv; |
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} else { |
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ckinv = in_kinv; |
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if (BN_copy(ret->r, in_r) == NULL) { |
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ECDSAerr(ECDSA_F_ECDSA_DO_SIGN, ERR_R_MALLOC_FAILURE); |
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goto err; |
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} |
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} |
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if (!BN_mod_mul(tmp, priv_key, ret->r, order, ctx)) { |
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ECDSAerr(ECDSA_F_ECDSA_DO_SIGN, ERR_R_BN_LIB); |
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goto err; |
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} |
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if (!BN_mod_add_quick(s, tmp, m, order)) { |
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ECDSAerr(ECDSA_F_ECDSA_DO_SIGN, ERR_R_BN_LIB); |
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goto err; |
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} |
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if (!BN_mod_mul(s, s, ckinv, order, ctx)) { |
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ECDSAerr(ECDSA_F_ECDSA_DO_SIGN, ERR_R_BN_LIB); |
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goto err; |
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} |
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if (BN_is_zero(s)) { |
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/* |
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* if kinv and r have been supplied by the caller don't to |
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* generate new kinv and r values |
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*/ |
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if (in_kinv != NULL && in_r != NULL) { |
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ECDSAerr(ECDSA_F_ECDSA_DO_SIGN, |
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ECDSA_R_NEED_NEW_SETUP_VALUES); |
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goto err; |
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} |
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} else |
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/* s != 0 => we have a valid signature */ |
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break; |
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} |
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while (1); |
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ok = 1; |
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err: |
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if (!ok) { |
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ECDSA_SIG_free(ret); |
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ret = NULL; |
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} |
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if (ctx) |
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BN_CTX_free(ctx); |
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if (m) |
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BN_clear_free(m); |
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if (tmp) |
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BN_clear_free(tmp); |
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if (order) |
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BN_free(order); |
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if (kinv) |
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BN_clear_free(kinv); |
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return ret; |
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} |
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static int ecdsa_do_verify(const unsigned char *dgst, int dgst_len, |
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const ECDSA_SIG *sig, EC_KEY *eckey) |
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{ |
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int ret = -1, i; |
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BN_CTX *ctx; |
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BIGNUM *order, *u1, *u2, *m, *X; |
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EC_POINT *point = NULL; |
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const EC_GROUP *group; |
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const EC_POINT *pub_key; |
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/* check input values */ |
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if (eckey == NULL || (group = EC_KEY_get0_group(eckey)) == NULL || |
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(pub_key = EC_KEY_get0_public_key(eckey)) == NULL || sig == NULL) { |
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ECDSAerr(ECDSA_F_ECDSA_DO_VERIFY, ECDSA_R_MISSING_PARAMETERS); |
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return -1; |
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} |
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ctx = BN_CTX_new(); |
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if (!ctx) { |
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ECDSAerr(ECDSA_F_ECDSA_DO_VERIFY, ERR_R_MALLOC_FAILURE); |
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return -1; |
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} |
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BN_CTX_start(ctx); |
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order = BN_CTX_get(ctx); |
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u1 = BN_CTX_get(ctx); |
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u2 = BN_CTX_get(ctx); |
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m = BN_CTX_get(ctx); |
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X = BN_CTX_get(ctx); |
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if (!X) { |
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ECDSAerr(ECDSA_F_ECDSA_DO_VERIFY, ERR_R_BN_LIB); |
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goto err; |
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} |
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if (!EC_GROUP_get_order(group, order, ctx)) { |
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ECDSAerr(ECDSA_F_ECDSA_DO_VERIFY, ERR_R_EC_LIB); |
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goto err; |
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} |
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if (BN_is_zero(sig->r) || BN_is_negative(sig->r) || |
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BN_ucmp(sig->r, order) >= 0 || BN_is_zero(sig->s) || |
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BN_is_negative(sig->s) || BN_ucmp(sig->s, order) >= 0) { |
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ECDSAerr(ECDSA_F_ECDSA_DO_VERIFY, ECDSA_R_BAD_SIGNATURE); |
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ret = 0; /* signature is invalid */ |
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goto err; |
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} |
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/* calculate tmp1 = inv(S) mod order */ |
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if (!BN_mod_inverse(u2, sig->s, order, ctx)) { |
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ECDSAerr(ECDSA_F_ECDSA_DO_VERIFY, ERR_R_BN_LIB); |
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goto err; |
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} |
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/* digest -> m */ |
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i = BN_num_bits(order); |
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/* |
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* Need to truncate digest if it is too long: first truncate whole bytes. |
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*/ |
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if (8 * dgst_len > i) |
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dgst_len = (i + 7) / 8; |
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if (!BN_bin2bn(dgst, dgst_len, m)) { |
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ECDSAerr(ECDSA_F_ECDSA_DO_VERIFY, ERR_R_BN_LIB); |
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goto err; |
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} |
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/* If still too long truncate remaining bits with a shift */ |
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if ((8 * dgst_len > i) && !BN_rshift(m, m, 8 - (i & 0x7))) { |
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ECDSAerr(ECDSA_F_ECDSA_DO_VERIFY, ERR_R_BN_LIB); |
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goto err; |
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} |
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/* u1 = m * tmp mod order */ |
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if (!BN_mod_mul(u1, m, u2, order, ctx)) { |
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ECDSAerr(ECDSA_F_ECDSA_DO_VERIFY, ERR_R_BN_LIB); |
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goto err; |
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} |
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/* u2 = r * w mod q */ |
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if (!BN_mod_mul(u2, sig->r, u2, order, ctx)) { |
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ECDSAerr(ECDSA_F_ECDSA_DO_VERIFY, ERR_R_BN_LIB); |
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goto err; |
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} |
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if ((point = EC_POINT_new(group)) == NULL) { |
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ECDSAerr(ECDSA_F_ECDSA_DO_VERIFY, ERR_R_MALLOC_FAILURE); |
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goto err; |
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} |
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if (!EC_POINT_mul(group, point, u1, pub_key, u2, ctx)) { |
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ECDSAerr(ECDSA_F_ECDSA_DO_VERIFY, ERR_R_EC_LIB); |
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goto err; |
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} |
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if (EC_METHOD_get_field_type(EC_GROUP_method_of(group)) == |
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NID_X9_62_prime_field) { |
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if (!EC_POINT_get_affine_coordinates_GFp(group, point, X, NULL, ctx)) { |
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ECDSAerr(ECDSA_F_ECDSA_DO_VERIFY, ERR_R_EC_LIB); |
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goto err; |
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} |
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} |
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#ifndef OPENSSL_NO_EC2M |
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else { /* NID_X9_62_characteristic_two_field */ |
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if (!EC_POINT_get_affine_coordinates_GF2m(group, point, X, NULL, ctx)) { |
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ECDSAerr(ECDSA_F_ECDSA_DO_VERIFY, ERR_R_EC_LIB); |
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goto err; |
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} |
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} |
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#endif |
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if (!BN_nnmod(u1, X, order, ctx)) { |
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ECDSAerr(ECDSA_F_ECDSA_DO_VERIFY, ERR_R_BN_LIB); |
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goto err; |
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} |
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/* if the signature is correct u1 is equal to sig->r */ |
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ret = (BN_ucmp(u1, sig->r) == 0); |
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err: |
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BN_CTX_end(ctx); |
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BN_CTX_free(ctx); |
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if (point) |
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EC_POINT_free(point); |
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return ret; |
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}
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