From d2b3db2860c962927def39a52f67f1c23f7b201a Mon Sep 17 00:00:00 2001 From: "jsing@openbsd.org" Date: Wed, 14 Feb 2018 16:27:24 +0000 Subject: upstream: Ensure that D mod (P-1) and D mod (Q-1) are calculated in constant time. This avoids a potential side channel timing leak. ok djm@ markus@ OpenBSD-Commit-ID: 71ff3c16be03290e63d8edab8fac053d8a82968c --- ssh-rsa.c | 18 ++++++++++-------- 1 file changed, 10 insertions(+), 8 deletions(-) (limited to 'ssh-rsa.c') diff --git a/ssh-rsa.c b/ssh-rsa.c index 89e3c8c74..49e71c87f 100644 --- a/ssh-rsa.c +++ b/ssh-rsa.c @@ -1,4 +1,4 @@ -/* $OpenBSD: ssh-rsa.c,v 1.65 2018/02/07 05:17:56 jsing Exp $ */ +/* $OpenBSD: ssh-rsa.c,v 1.66 2018/02/14 16:27:24 jsing Exp $ */ /* * Copyright (c) 2000, 2003 Markus Friedl * @@ -79,13 +79,12 @@ rsa_hash_alg_nid(int type) } } -/* calculate p-1 and q-1 */ int ssh_rsa_generate_additional_parameters(struct sshkey *key) { - RSA *rsa; BIGNUM *aux = NULL; BN_CTX *ctx = NULL; + BIGNUM d; int r; if (key == NULL || key->rsa == NULL || @@ -98,12 +97,15 @@ ssh_rsa_generate_additional_parameters(struct sshkey *key) r = SSH_ERR_ALLOC_FAIL; goto out; } - rsa = key->rsa; + BN_set_flags(aux, BN_FLG_CONSTTIME); - if ((BN_sub(aux, rsa->q, BN_value_one()) == 0) || - (BN_mod(rsa->dmq1, rsa->d, aux, ctx) == 0) || - (BN_sub(aux, rsa->p, BN_value_one()) == 0) || - (BN_mod(rsa->dmp1, rsa->d, aux, ctx) == 0)) { + BN_init(&d); + BN_with_flags(&d, key->rsa->d, BN_FLG_CONSTTIME); + + if ((BN_sub(aux, key->rsa->q, BN_value_one()) == 0) || + (BN_mod(key->rsa->dmq1, &d, aux, ctx) == 0) || + (BN_sub(aux, key->rsa->p, BN_value_one()) == 0) || + (BN_mod(key->rsa->dmp1, &d, aux, ctx) == 0)) { r = SSH_ERR_LIBCRYPTO_ERROR; goto out; } -- cgit v1.2.3