diff options
| author | Bodo Möller <bodo@openssl.org> | 2005-05-16 01:43:31 +0000 |
|---|---|---|
| committer | Bodo Möller <bodo@openssl.org> | 2005-05-16 01:43:31 +0000 |
| commit | 46a643763de6d8e39ecf6f76fa79b4d04885aa59 (patch) | |
| tree | e1f3cfc98bddba797b5300977dbf3223f008fc4a /crypto/dsa/dsa_ossl.c | |
| parent | 92c44685724c0d993ea8920577680f3c0a1d79c8 (diff) | |
Implement fixed-window exponentiation to mitigate hyper-threading
timing attacks.
BN_FLG_EXP_CONSTTIME requests this algorithm, and this done by default for
RSA/DSA/DH private key computations unless
RSA_FLAG_NO_EXP_CONSTTIME/DSA_FLAG_NO_EXP_CONSTTIME/
DH_FLAG_NO_EXP_CONSTTIME is set.
Submitted by: Matthew D Wood
Reviewed by: Bodo Moeller
Diffstat (limited to 'crypto/dsa/dsa_ossl.c')
| -rw-r--r-- | crypto/dsa/dsa_ossl.c | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/crypto/dsa/dsa_ossl.c b/crypto/dsa/dsa_ossl.c index 25cd8484aa..2e5ede7826 100644 --- a/crypto/dsa/dsa_ossl.c +++ b/crypto/dsa/dsa_ossl.c @@ -227,6 +227,10 @@ static int dsa_sign_setup(DSA *dsa, BN_CTX *ctx_in, BIGNUM **kinvp, BIGNUM **rp) do if (!BN_rand_range(&k, dsa->q)) goto err; while (BN_is_zero(&k)); + if ((dsa->flags & DSA_FLAG_NO_EXP_CONSTTIME) == 0) + { + BN_set_flags(&k, BN_FLG_EXP_CONSTTIME); + } if (dsa->flags & DSA_FLAG_CACHE_MONT_P) { |