diff options
Diffstat (limited to 'deps/openssl/openssl/crypto/dsa/dsa_ossl.c')
-rw-r--r-- | deps/openssl/openssl/crypto/dsa/dsa_ossl.c | 68 |
1 files changed, 50 insertions, 18 deletions
diff --git a/deps/openssl/openssl/crypto/dsa/dsa_ossl.c b/deps/openssl/openssl/crypto/dsa/dsa_ossl.c index 7f48cf2e33..4aa49f554a 100644 --- a/deps/openssl/openssl/crypto/dsa/dsa_ossl.c +++ b/deps/openssl/openssl/crypto/dsa/dsa_ossl.c @@ -1,5 +1,5 @@ /* - * Copyright 1995-2016 The OpenSSL Project Authors. All Rights Reserved. + * Copyright 1995-2018 The OpenSSL Project Authors. All Rights Reserved. * * Licensed under the OpenSSL license (the "License"). You may not use * this file except in compliance with the License. You can obtain a copy @@ -61,19 +61,13 @@ const DSA_METHOD *DSA_OpenSSL(void) static DSA_SIG *dsa_do_sign(const unsigned char *dgst, int dlen, DSA *dsa) { BIGNUM *kinv = NULL; - BIGNUM *m; - BIGNUM *xr; + BIGNUM *m, *blind, *blindm, *tmp; BN_CTX *ctx = NULL; int reason = ERR_R_BN_LIB; DSA_SIG *ret = NULL; int rv = 0; - m = BN_new(); - xr = BN_new(); - if (m == NULL || xr == NULL) - goto err; - - if (!dsa->p || !dsa->q || !dsa->g) { + if (dsa->p == NULL || dsa->q == NULL || dsa->g == NULL) { reason = DSA_R_MISSING_PARAMETERS; goto err; } @@ -89,6 +83,13 @@ static DSA_SIG *dsa_do_sign(const unsigned char *dgst, int dlen, DSA *dsa) ctx = BN_CTX_new(); if (ctx == NULL) goto err; + m = BN_CTX_get(ctx); + blind = BN_CTX_get(ctx); + blindm = BN_CTX_get(ctx); + tmp = BN_CTX_get(ctx); + if (tmp == NULL) + goto err; + redo: if (!dsa_sign_setup(dsa, ctx, &kinv, &ret->r, dgst, dlen)) goto err; @@ -103,17 +104,50 @@ static DSA_SIG *dsa_do_sign(const unsigned char *dgst, int dlen, DSA *dsa) if (BN_bin2bn(dgst, dlen, m) == NULL) goto err; - /* Compute s = inv(k) (m + xr) mod q */ - if (!BN_mod_mul(xr, dsa->priv_key, ret->r, dsa->q, ctx)) - goto err; /* s = xr */ - if (!BN_add(ret->s, xr, m)) - goto err; /* s = m + xr */ - if (BN_cmp(ret->s, dsa->q) > 0) - if (!BN_sub(ret->s, ret->s, dsa->q)) + /* + * The normal signature calculation is: + * + * s := k^-1 * (m + r * priv_key) mod q + * + * We will blind this to protect against side channel attacks + * + * s := blind^-1 * k^-1 * (blind * m + blind * r * priv_key) mod q + */ + + /* Generate a blinding value */ + do { + if (!BN_rand(blind, BN_num_bits(dsa->q) - 1, BN_RAND_TOP_ANY, + BN_RAND_BOTTOM_ANY)) goto err; + } while (BN_is_zero(blind)); + BN_set_flags(blind, BN_FLG_CONSTTIME); + BN_set_flags(blindm, BN_FLG_CONSTTIME); + BN_set_flags(tmp, BN_FLG_CONSTTIME); + + /* tmp := blind * priv_key * r mod q */ + if (!BN_mod_mul(tmp, blind, dsa->priv_key, dsa->q, ctx)) + goto err; + if (!BN_mod_mul(tmp, tmp, ret->r, dsa->q, ctx)) + goto err; + + /* blindm := blind * m mod q */ + if (!BN_mod_mul(blindm, blind, m, dsa->q, ctx)) + goto err; + + /* s : = (blind * priv_key * r) + (blind * m) mod q */ + if (!BN_mod_add_quick(ret->s, tmp, blindm, dsa->q)) + goto err; + + /* s := s * k^-1 mod q */ if (!BN_mod_mul(ret->s, ret->s, kinv, dsa->q, ctx)) goto err; + /* s:= s * blind^-1 mod q */ + if (BN_mod_inverse(blind, blind, dsa->q, ctx) == NULL) + goto err; + if (!BN_mod_mul(ret->s, ret->s, blind, dsa->q, ctx)) + goto err; + /* * Redo if r or s is zero as required by FIPS 186-3: this is very * unlikely. @@ -130,8 +164,6 @@ static DSA_SIG *dsa_do_sign(const unsigned char *dgst, int dlen, DSA *dsa) ret = NULL; } BN_CTX_free(ctx); - BN_clear_free(m); - BN_clear_free(xr); BN_clear_free(kinv); return ret; } |