diff options
Diffstat (limited to 'crypto/ecdsa/ecs_ossl.c')
| -rw-r--r-- | crypto/ecdsa/ecs_ossl.c | 32 |
1 files changed, 23 insertions, 9 deletions
diff --git a/crypto/ecdsa/ecs_ossl.c b/crypto/ecdsa/ecs_ossl.c index 16d4f59b9ba9..63c18273fd87 100644 --- a/crypto/ecdsa/ecs_ossl.c +++ b/crypto/ecdsa/ecs_ossl.c @@ -3,7 +3,7 @@ * Written by Nils Larsch for the OpenSSL project */ /* ==================================================================== - * Copyright (c) 1998-2004 The OpenSSL Project. All rights reserved. + * Copyright (c) 1998-2018 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 @@ -60,6 +60,7 @@ #include <openssl/err.h> #include <openssl/obj_mac.h> #include <openssl/bn.h> +#include "bn_int.h" static ECDSA_SIG *ecdsa_do_sign(const unsigned char *dgst, int dlen, const BIGNUM *, const BIGNUM *, @@ -251,13 +252,14 @@ static ECDSA_SIG *ecdsa_do_sign(const unsigned char *dgst, int dgst_len, EC_KEY *eckey) { int ok = 0, i; - BIGNUM *kinv = NULL, *s, *m = NULL, *tmp = NULL, *order = NULL; + BIGNUM *kinv = NULL, *s, *m = NULL, *order = NULL; const BIGNUM *ckinv; BN_CTX *ctx = NULL; const EC_GROUP *group; ECDSA_SIG *ret; ECDSA_DATA *ecdsa; const BIGNUM *priv_key; + BN_MONT_CTX *mont_data; ecdsa = ecdsa_check(eckey); group = EC_KEY_get0_group(eckey); @@ -276,7 +278,7 @@ static ECDSA_SIG *ecdsa_do_sign(const unsigned char *dgst, int dgst_len, s = ret->s; if ((ctx = BN_CTX_new()) == NULL || (order = BN_new()) == NULL || - (tmp = BN_new()) == NULL || (m = BN_new()) == NULL) { + (m = BN_new()) == NULL) { ECDSAerr(ECDSA_F_ECDSA_DO_SIGN, ERR_R_MALLOC_FAILURE); goto err; } @@ -285,6 +287,8 @@ static ECDSA_SIG *ecdsa_do_sign(const unsigned char *dgst, int dgst_len, ECDSAerr(ECDSA_F_ECDSA_DO_SIGN, ERR_R_EC_LIB); goto err; } + mont_data = EC_GROUP_get_mont_data(group); + i = BN_num_bits(order); /* * Need to truncate digest if it is too long: first truncate whole bytes. @@ -315,15 +319,27 @@ static ECDSA_SIG *ecdsa_do_sign(const unsigned char *dgst, int dgst_len, } } - if (!BN_mod_mul(tmp, priv_key, ret->r, order, ctx)) { - ECDSAerr(ECDSA_F_ECDSA_DO_SIGN, ERR_R_BN_LIB); + /* + * 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, mont_data, ctx) + || !bn_mul_mont_fixed_top(s, s, priv_key, mont_data, ctx)) { goto err; } - if (!BN_mod_add_quick(s, tmp, m, order)) { + if (!bn_mod_add_fixed_top(s, s, m, order)) { ECDSAerr(ECDSA_F_ECDSA_DO_SIGN, 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, mont_data, ctx) + || !BN_mod_mul_montgomery(s, s, ckinv, mont_data, ctx)) { ECDSAerr(ECDSA_F_ECDSA_DO_SIGN, ERR_R_BN_LIB); goto err; } @@ -353,8 +369,6 @@ static ECDSA_SIG *ecdsa_do_sign(const unsigned char *dgst, int dgst_len, BN_CTX_free(ctx); if (m) BN_clear_free(m); - if (tmp) - BN_clear_free(tmp); if (order) BN_free(order); if (kinv) |