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SAE: Implement retransmission timer 

Add the t0 retransmission timer as specified by IEEE Std 802.11-2012,
11.3.8.4. This makes SAE much more likely to succeed in the case of lost
frames.

Signed-off-by: Bob Copeland <me@bobcopeland.com>
This commit is contained in:
Bob Copeland 2015-01-07 01:10:57 -05:00 committed by Jouni Malinen
parent a206e2a175
commit f3b8ad4d78
4 changed files with 103 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

93
src/ap/ieee802_11.c
View File

@ -328,6 +328,10 @@ static void handle_auth_ft_finish(void *ctx, const u8 *dst, const u8 *bssid,
#ifdef CONFIG_SAE
#define dot11RSNASAERetransPeriod 40 /* msec */
#define dot11RSNASAESync 5 /* attempts */
static struct wpabuf * auth_build_sae_commit(struct hostapd_data *hapd,
struct sta_info *sta, int update)
{
@ -483,6 +487,66 @@ static struct wpabuf * auth_build_token_req(struct hostapd_data *hapd,
}
static int sae_check_big_sync(struct sta_info *sta)
{
if (sta->sae->sync > dot11RSNASAESync) {
sta->sae->state = SAE_NOTHING;
sta->sae->sync = 0;
return -1;
}
return 0;
}
static void auth_sae_retransmit_timer(void *eloop_ctx, void *eloop_data)
{
struct hostapd_data *hapd = eloop_ctx;
struct sta_info *sta = eloop_data;
int ret;
if (sae_check_big_sync(sta))
return;
sta->sae->sync++;
switch (sta->sae->state) {
case SAE_COMMITTED:
ret = auth_sae_send_commit(hapd, sta, hapd->own_addr, 0);
eloop_register_timeout(0, dot11RSNASAERetransPeriod * 1000,
auth_sae_retransmit_timer, hapd, sta);
break;
case SAE_CONFIRMED:
ret = auth_sae_send_confirm(hapd, sta, hapd->own_addr);
eloop_register_timeout(0, dot11RSNASAERetransPeriod * 1000,
auth_sae_retransmit_timer, hapd, sta);
break;
default:
ret = -1;
break;
}
if (ret != WLAN_STATUS_SUCCESS)
wpa_printf(MSG_INFO, "SAE: Failed to retransmit: ret=%d", ret);
}
void sae_clear_retransmit_timer(struct hostapd_data *hapd, struct sta_info *sta)
{
eloop_cancel_timeout(auth_sae_retransmit_timer, hapd, sta);
}
static void sae_set_retransmit_timer(struct hostapd_data *hapd,
struct sta_info *sta)
{
if (!(hapd->conf->mesh & MESH_ENABLED))
return;
eloop_cancel_timeout(auth_sae_retransmit_timer, hapd, sta);
eloop_register_timeout(0, dot11RSNASAERetransPeriod * 1000,
auth_sae_retransmit_timer, hapd, sta);
}
static int sae_sm_step(struct hostapd_data *hapd, struct sta_info *sta,
const u8 *bssid, u8 auth_transaction)
{
@ -530,6 +594,8 @@ static int sae_sm_step(struct hostapd_data *hapd, struct sta_info *sta,
* when receiving Confirm from STA.
*/
}
sta->sae->sync = 0;
sae_set_retransmit_timer(hapd, sta);
} else {
hostapd_logger(hapd, sta->addr,
HOSTAPD_MODULE_IEEE80211,
@ -538,6 +604,7 @@ static int sae_sm_step(struct hostapd_data *hapd, struct sta_info *sta,
}
break;
case SAE_COMMITTED:
sae_clear_retransmit_timer(hapd, sta);
if (auth_transaction == 1) {
if (sae_process_commit(sta->sae) < 0)
return WLAN_STATUS_UNSPECIFIED_FAILURE;
@ -546,14 +613,22 @@ static int sae_sm_step(struct hostapd_data *hapd, struct sta_info *sta,
if (ret)
return ret;
sta->sae->state = SAE_CONFIRMED;
sta->sae->sync = 0;
sae_set_retransmit_timer(hapd, sta);
} else if (hapd->conf->mesh & MESH_ENABLED) {
/*
* In mesh case, follow SAE finite state machine and
* send Commit now.
* send Commit now, if sync count allows.
*/
if (sae_check_big_sync(sta))
return WLAN_STATUS_SUCCESS;
sta->sae->sync++;
ret = auth_sae_send_commit(hapd, sta, bssid, 1);
if (ret)
return ret;
sae_set_retransmit_timer(hapd, sta);
} else {
/*
* For instructure BSS, send the postponed Confirm from
@ -575,7 +650,12 @@ static int sae_sm_step(struct hostapd_data *hapd, struct sta_info *sta,
}
break;
case SAE_CONFIRMED:
sae_clear_retransmit_timer(hapd, sta);
if (auth_transaction == 1) {
if (sae_check_big_sync(sta))
return WLAN_STATUS_SUCCESS;
sta->sae->sync++;
ret = auth_sae_send_commit(hapd, sta, bssid, 1);
if (ret)
return ret;
@ -586,6 +666,8 @@ static int sae_sm_step(struct hostapd_data *hapd, struct sta_info *sta,
ret = auth_sae_send_confirm(hapd, sta, bssid);
if (ret)
return ret;
sae_set_retransmit_timer(hapd, sta);
} else {
sta->flags |= WLAN_STA_AUTH;
sta->auth_alg = WLAN_AUTH_SAE;
@ -603,6 +685,10 @@ static int sae_sm_step(struct hostapd_data *hapd, struct sta_info *sta,
MAC2STR(sta->addr));
ap_free_sta(hapd, sta);
} else {
if (sae_check_big_sync(sta))
return WLAN_STATUS_SUCCESS;
sta->sae->sync++;
ret = auth_sae_send_confirm(hapd, sta, bssid);
sae_clear_temp_data(sta->sae);
if (ret)
@ -632,6 +718,7 @@ static void handle_auth_sae(struct hostapd_data *hapd, struct sta_info *sta,
if (sta->sae == NULL)
return;
sta->sae->state = SAE_NOTHING;
sta->sae->sync = 0;
}
if (auth_transaction == 1) {
@ -685,6 +772,8 @@ static void handle_auth_sae(struct hostapd_data *hapd, struct sta_info *sta,
return;
}
sta->sae->state = SAE_COMMITTED;
sta->sae->sync = 0;
sae_set_retransmit_timer(hapd, sta);
return;
}
@ -782,6 +871,8 @@ int auth_sae_init_committed(struct hostapd_data *hapd, struct sta_info *sta)
return -1;
sta->sae->state = SAE_COMMITTED;
sta->sae->sync = 0;
sae_set_retransmit_timer(hapd, sta);
return 0;
}

9
src/ap/ieee802_11.h
View File

@ -90,5 +90,14 @@ void hostapd_client_poll_ok(struct hostapd_data *hapd, const u8 *addr);
u8 * hostapd_eid_bss_max_idle_period(struct hostapd_data *hapd, u8 *eid);
int auth_sae_init_committed(struct hostapd_data *hapd, struct sta_info *sta);
#ifdef CONFIG_SAE
void sae_clear_retransmit_timer(struct hostapd_data *hapd,
struct sta_info *sta);
#else /* CONFIG_SAE */
static inline void sae_clear_retransmit_timer(struct hostapd_data *hapd,
struct sta_info *sta)
{
}
#endif /* CONFIG_SAE */
#endif /* IEEE802_11_H */

1
src/ap/sta_info.c
View File

@ -250,6 +250,7 @@ void ap_free_sta(struct hostapd_data *hapd, struct sta_info *sta)
eloop_cancel_timeout(ap_handle_session_warning_timer, hapd, sta);
eloop_cancel_timeout(ap_sta_deauth_cb_timeout, hapd, sta);
eloop_cancel_timeout(ap_sta_disassoc_cb_timeout, hapd, sta);
sae_clear_retransmit_timer(hapd, sta);
ieee802_1x_free_station(sta);
wpa_auth_sta_deinit(sta->wpa_sm);

1
src/common/sae.h
View File

@ -44,6 +44,7 @@ struct sae_data {
u8 pmk[SAE_PMK_LEN];
struct crypto_bignum *peer_commit_scalar;
int group;
int sync;
struct sae_temporary_data *tmp;
};