From f119d6694250d5ac4105da72ddbdbe793251d230 Mon Sep 17 00:00:00 2001 From: Florent Daigniere Date: Fri, 27 Jun 2014 12:24:30 +0200 Subject: [PATCH] EAP-pwd: Verify BN_rand_range return code This makes the EAP-pwd server and peer implementations more robust should OpenSSL fail to derive random number for some reason. While this is unlikely to happen in practice, the implementation better be prepared for this should something unexpected ever happen. See http://jbp.io/2014/01/16/openssl-rand-api/#review-of-randbytes-callers for more details. Signed-off-by: Florent Daigniere --- src/eap_peer/eap_pwd.c | 14 +++++++++----- src/eap_server/eap_server_pwd.c | 14 +++++++++----- 2 files changed, 18 insertions(+), 10 deletions(-) diff --git a/src/eap_peer/eap_pwd.c b/src/eap_peer/eap_pwd.c index ef80dba35..fd5c2f0f5 100644 --- a/src/eap_peer/eap_pwd.c +++ b/src/eap_peer/eap_pwd.c @@ -317,11 +317,15 @@ eap_pwd_perform_commit_exchange(struct eap_sm *sm, struct eap_pwd_data *data, goto fin; } - BN_rand_range(data->private_value, data->grp->order); - BN_rand_range(mask, data->grp->order); - BN_add(data->my_scalar, data->private_value, mask); - BN_mod(data->my_scalar, data->my_scalar, data->grp->order, - data->bnctx); + if (BN_rand_range(data->private_value, data->grp->order) != 1 || + BN_rand_range(mask, data->grp->order) != 1 || + BN_add(data->my_scalar, data->private_value, mask) != 1 || + BN_mod(data->my_scalar, data->my_scalar, data->grp->order, + data->bnctx) != 1) { + wpa_printf(MSG_INFO, + "EAP-pwd (peer): unable to get randomness"); + goto fin; + } if (!EC_POINT_mul(data->grp->group, data->my_element, NULL, data->grp->pwe, mask, data->bnctx)) { diff --git a/src/eap_server/eap_server_pwd.c b/src/eap_server/eap_server_pwd.c index fc2ae263e..ed7dda109 100644 --- a/src/eap_server/eap_server_pwd.c +++ b/src/eap_server/eap_server_pwd.c @@ -210,11 +210,15 @@ static void eap_pwd_build_commit_req(struct eap_sm *sm, goto fin; } - BN_rand_range(data->private_value, data->grp->order); - BN_rand_range(mask, data->grp->order); - BN_add(data->my_scalar, data->private_value, mask); - BN_mod(data->my_scalar, data->my_scalar, data->grp->order, - data->bnctx); + if (BN_rand_range(data->private_value, data->grp->order) != 1 || + BN_rand_range(mask, data->grp->order) != 1 || + BN_add(data->my_scalar, data->private_value, mask) != 1 || + BN_mod(data->my_scalar, data->my_scalar, data->grp->order, + data->bnctx) != 1) { + wpa_printf(MSG_INFO, + "EAP-pwd (server): unable to get randomness"); + goto fin; + } if (!EC_POINT_mul(data->grp->group, data->my_element, NULL, data->grp->pwe, mask, data->bnctx)) {