diff options
author | Dr. Stephen Henson <steve@openssl.org> | 2015-10-27 16:48:36 +0000 |
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committer | Dr. Stephen Henson <steve@openssl.org> | 2015-12-09 22:09:18 +0000 |
commit | 0a6f1d97330f777f9bcf5fa4f91390b59b737975 (patch) | |
tree | ab476be1769a2a242735cc1b4058f0468e0dad17 /crypto/ec/ecdsa_ossl.c | |
parent | 2d3d00dcd85fcf6dfacebe03e1bf59388849159e (diff) | |
download | openssl-0a6f1d97330f777f9bcf5fa4f91390b59b737975.tar.gz |
Move ECDSA implementation to crypto/ec
Reviewed-by: Richard Levitte <levitte@openssl.org>
Diffstat (limited to 'crypto/ec/ecdsa_ossl.c')
-rw-r--r-- | crypto/ec/ecdsa_ossl.c | 468 |
1 files changed, 468 insertions, 0 deletions
diff --git a/crypto/ec/ecdsa_ossl.c b/crypto/ec/ecdsa_ossl.c new file mode 100644 index 0000000000..bff80f9e11 --- /dev/null +++ b/crypto/ec/ecdsa_ossl.c @@ -0,0 +1,468 @@ +/* crypto/ecdsa/ecs_ossl.c */ +/* + * Written by Nils Larsch for the OpenSSL project + */ +/* ==================================================================== + * Copyright (c) 1998-2004 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 "ecs_locl.h" +#include <openssl/err.h> +#include <openssl/obj_mac.h> +#include <openssl/bn.h> +#include <openssl/rand.h> + +static ECDSA_SIG *ecdsa_do_sign(const unsigned char *dgst, int dlen, + const BIGNUM *, const BIGNUM *, + EC_KEY *eckey); +static int ecdsa_sign_setup_no_digest(EC_KEY *eckey, BN_CTX *ctx_in, + BIGNUM **kinvp, BIGNUM **rp); +static int ecdsa_sign_setup(EC_KEY *eckey, BN_CTX *ctx_in, BIGNUM **kinvp, + BIGNUM **rp, const unsigned char *dgst, int dlen); +static int ecdsa_do_verify(const unsigned char *dgst, int dgst_len, + const ECDSA_SIG *sig, EC_KEY *eckey); + +static ECDSA_METHOD openssl_ecdsa_meth = { + "OpenSSL ECDSA method", + ecdsa_do_sign, + ecdsa_sign_setup_no_digest, + ecdsa_do_verify, + ECDSA_FLAG_FIPS_METHOD, /* flags */ + NULL /* app_data */ +}; + +const ECDSA_METHOD *ECDSA_OpenSSL(void) +{ + return &openssl_ecdsa_meth; +} + +static int ecdsa_sign_setup_no_digest(EC_KEY *eckey, + BN_CTX *ctx_in, BIGNUM **kinvp, + BIGNUM **rp) +{ + return ecdsa_sign_setup(eckey, ctx_in, kinvp, rp, NULL, 0); +} + +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, *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) { + ECDSAerr(ECDSA_F_ECDSA_SIGN_SETUP, ERR_R_PASSED_NULL_PARAMETER); + return 0; + } + + if (ctx_in == NULL) { + if ((ctx = BN_CTX_new()) == NULL) { + ECDSAerr(ECDSA_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 */ + order = BN_new(); + X = BN_new(); + if (k == NULL || r == NULL || order == NULL || X == NULL) { + ECDSAerr(ECDSA_F_ECDSA_SIGN_SETUP, ERR_R_MALLOC_FAILURE); + goto err; + } + if ((tmp_point = EC_POINT_new(group)) == NULL) { + ECDSAerr(ECDSA_F_ECDSA_SIGN_SETUP, ERR_R_EC_LIB); + goto err; + } + if (!EC_GROUP_get_order(group, order, ctx)) { + ECDSAerr(ECDSA_F_ECDSA_SIGN_SETUP, ERR_R_EC_LIB); + goto err; + } + + do { + /* get random k */ + do + if (dgst != NULL) { + if (!BN_generate_dsa_nonce + (k, order, EC_KEY_get0_private_key(eckey), dgst, dlen, + ctx)) { + ECDSAerr(ECDSA_F_ECDSA_SIGN_SETUP, + ECDSA_R_RANDOM_NUMBER_GENERATION_FAILED); + goto err; + } + } else { + if (!BN_rand_range(k, order)) { + ECDSAerr(ECDSA_F_ECDSA_SIGN_SETUP, + 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)) { + ECDSAerr(ECDSA_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)) { + ECDSAerr(ECDSA_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)) { + ECDSAerr(ECDSA_F_ECDSA_SIGN_SETUP, ERR_R_EC_LIB); + goto err; + } + } +#endif + if (!BN_nnmod(r, X, order, ctx)) { + ECDSAerr(ECDSA_F_ECDSA_SIGN_SETUP, ERR_R_BN_LIB); + goto err; + } + } + 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)) { + ECDSAerr(ECDSA_F_ECDSA_SIGN_SETUP, ERR_R_BN_LIB); + goto err; + } + if (!BN_mod_sub(X, order, X, order, ctx)) { + ECDSAerr(ECDSA_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))) { + ECDSAerr(ECDSA_F_ECDSA_SIGN_SETUP, ERR_R_BN_LIB); + goto err; + } + } else { + if (!BN_mod_inverse(k, k, order, ctx)) { + ECDSAerr(ECDSA_F_ECDSA_SIGN_SETUP, 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); + BN_free(order); + EC_POINT_free(tmp_point); + BN_clear_free(X); + return (ret); +} + +static ECDSA_SIG *ecdsa_do_sign(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, *tmp = NULL, *order = NULL; + const BIGNUM *ckinv; + BN_CTX *ctx = NULL; + const EC_GROUP *group; + ECDSA_SIG *ret; + ECDSA_DATA *ecdsa; + const BIGNUM *priv_key; + + ecdsa = ecdsa_check(eckey); + group = EC_KEY_get0_group(eckey); + priv_key = EC_KEY_get0_private_key(eckey); + + if (group == NULL || priv_key == NULL || ecdsa == NULL) { + ECDSAerr(ECDSA_F_ECDSA_DO_SIGN, ERR_R_PASSED_NULL_PARAMETER); + return NULL; + } + + ret = ECDSA_SIG_new(); + if (ret == NULL) { + ECDSAerr(ECDSA_F_ECDSA_DO_SIGN, 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) { + ECDSAerr(ECDSA_F_ECDSA_DO_SIGN, ERR_R_MALLOC_FAILURE); + goto err; + } + + if (!EC_GROUP_get_order(group, order, ctx)) { + ECDSAerr(ECDSA_F_ECDSA_DO_SIGN, ERR_R_EC_LIB); + goto err; + } + 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)) { + ECDSAerr(ECDSA_F_ECDSA_DO_SIGN, 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))) { + ECDSAerr(ECDSA_F_ECDSA_DO_SIGN, 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)) { + ECDSAerr(ECDSA_F_ECDSA_DO_SIGN, ERR_R_ECDSA_LIB); + goto err; + } + ckinv = kinv; + } else { + ckinv = in_kinv; + if (BN_copy(ret->r, in_r) == NULL) { + ECDSAerr(ECDSA_F_ECDSA_DO_SIGN, ERR_R_MALLOC_FAILURE); + goto err; + } + } + + if (!BN_mod_mul(tmp, priv_key, ret->r, order, ctx)) { + ECDSAerr(ECDSA_F_ECDSA_DO_SIGN, ERR_R_BN_LIB); + goto err; + } + if (!BN_mod_add_quick(s, tmp, m, order)) { + ECDSAerr(ECDSA_F_ECDSA_DO_SIGN, ERR_R_BN_LIB); + goto err; + } + if (!BN_mod_mul(s, s, ckinv, order, ctx)) { + ECDSAerr(ECDSA_F_ECDSA_DO_SIGN, 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) { + ECDSAerr(ECDSA_F_ECDSA_DO_SIGN, + ECDSA_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(tmp); + BN_free(order); + BN_clear_free(kinv); + return ret; +} + +static int ecdsa_do_verify(const unsigned char *dgst, int dgst_len, + const ECDSA_SIG *sig, EC_KEY *eckey) +{ + int ret = -1, i; + BN_CTX *ctx; + BIGNUM *order, *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) { + ECDSAerr(ECDSA_F_ECDSA_DO_VERIFY, ECDSA_R_MISSING_PARAMETERS); + return -1; + } + + ctx = BN_CTX_new(); + if (ctx == NULL) { + ECDSAerr(ECDSA_F_ECDSA_DO_VERIFY, ERR_R_MALLOC_FAILURE); + return -1; + } + 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) { + ECDSAerr(ECDSA_F_ECDSA_DO_VERIFY, ERR_R_BN_LIB); + goto err; + } + + if (!EC_GROUP_get_order(group, order, ctx)) { + ECDSAerr(ECDSA_F_ECDSA_DO_VERIFY, 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) { + ECDSAerr(ECDSA_F_ECDSA_DO_VERIFY, 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)) { + ECDSAerr(ECDSA_F_ECDSA_DO_VERIFY, 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)) { + ECDSAerr(ECDSA_F_ECDSA_DO_VERIFY, 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))) { + ECDSAerr(ECDSA_F_ECDSA_DO_VERIFY, ERR_R_BN_LIB); + goto err; + } + /* u1 = m * tmp mod order */ + if (!BN_mod_mul(u1, m, u2, order, ctx)) { + ECDSAerr(ECDSA_F_ECDSA_DO_VERIFY, ERR_R_BN_LIB); + goto err; + } + /* u2 = r * w mod q */ + if (!BN_mod_mul(u2, sig->r, u2, order, ctx)) { + ECDSAerr(ECDSA_F_ECDSA_DO_VERIFY, ERR_R_BN_LIB); + goto err; + } + + if ((point = EC_POINT_new(group)) == NULL) { + ECDSAerr(ECDSA_F_ECDSA_DO_VERIFY, ERR_R_MALLOC_FAILURE); + goto err; + } + if (!EC_POINT_mul(group, point, u1, pub_key, u2, ctx)) { + ECDSAerr(ECDSA_F_ECDSA_DO_VERIFY, 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)) { + ECDSAerr(ECDSA_F_ECDSA_DO_VERIFY, 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)) { + ECDSAerr(ECDSA_F_ECDSA_DO_VERIFY, ERR_R_EC_LIB); + goto err; + } + } +#endif + if (!BN_nnmod(u1, X, order, ctx)) { + ECDSAerr(ECDSA_F_ECDSA_DO_VERIFY, 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; +} |