From adaebd81a01e2926a3106feec0476db7c8d7b362 Mon Sep 17 00:00:00 2001 From: Cesar Pereida Garcia Date: Thu, 5 Sep 2019 17:47:40 +0300 Subject: [PATCH] [crypto/rsa] Fix multiple SCA vulnerabilities during RSA key validation. This commit addresses multiple side-channel vulnerabilities present during RSA key validation. Private key parameters are re-computed using variable-time functions. This issue was discovered and reported by the NISEC group at TAU Finland. Reviewed-by: Bernd Edlinger Reviewed-by: Matt Caswell (Merged from https://github.com/openssl/openssl/pull/9785) --- crypto/rsa/rsa_chk.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/crypto/rsa/rsa_chk.c b/crypto/rsa/rsa_chk.c index 475dfc5628..3ea4e02974 100644 --- a/crypto/rsa/rsa_chk.c +++ b/crypto/rsa/rsa_chk.c @@ -63,6 +63,10 @@ int RSA_check_key(const RSA *key) return 0; } + /* Set consant-time flag on private parameters */ + BN_set_flags(key->p, BN_FLG_CONSTTIME); + BN_set_flags(key->q, BN_FLG_CONSTTIME); + BN_set_flags(key->d, BN_FLG_CONSTTIME); i = BN_new(); j = BN_new(); k = BN_new(); @@ -141,6 +145,10 @@ int RSA_check_key(const RSA *key) } if (key->dmp1 != NULL && key->dmq1 != NULL && key->iqmp != NULL) { + /* Set consant-time flag on CRT parameters */ + BN_set_flags(key->dmp1, BN_FLG_CONSTTIME); + BN_set_flags(key->dmq1, BN_FLG_CONSTTIME); + BN_set_flags(key->iqmp, BN_FLG_CONSTTIME); /* dmp1 = d mod (p-1)? */ if (!BN_sub(i, key->p, BN_value_one())) { ret = -1; -- 2.25.1