From bfcdac1c8bb7189310d0797b9bdf19d92d0414f3 Mon Sep 17 00:00:00 2001 From: "Arnout Vandecappelle (Essensium/Mind)" Date: Tue, 12 Feb 2019 15:35:23 +0100 Subject: [PATCH] Multi-AP: Don't reject backhaul STA on fronthaul BSS The Multi-AP specification only specifies that information elements have to be added to the Association Request and Association Response frame; it doesn't specify anything about what should be done in case they are missing. Previously, we rejected non-backhaul associations on a backhaul-only BSS, and non-fronthaul associations on a fronthaul-only BSS. However, this makes WPS fail when fronthaul and backhaul are separate SSIDs. Indeed, WPS for the backhaul link is performed on the *fronthaul* SSID. Thus, the Association Request frmae used for WPS *will* contain the Multi-AP IE indicating a backhaul STA. Rejecting that association makes WPS fail. Therefore, accept a multi-AP backhaul STA Association Request frame on a fronthaul-only BSS. Still issue a warning about it, but only at level DEBUG intead of INFO. Also change the condition checking to make it clearer. While we're at it, also fix the handling of unexpected bits in the Multi-AP IE. 4 bits are reserved in the specification, so these certainly have to be ignored. The specification also doesn't say that setting one of the other bits is not allowed. Therefore, only report unexpected values in the Multi-AP IE, don't reject because of it. Note that a malformed IE (containing more than one byte) still triggers a rejection. Signed-off-by: Arnout Vandecappelle (Essensium/Mind) --- src/ap/ieee802_11.c | 38 ++++++++++++++++++++------------------ 1 file changed, 20 insertions(+), 18 deletions(-) diff --git a/src/ap/ieee802_11.c b/src/ap/ieee802_11.c index bc45cd71f..80d2d67ea 100644 --- a/src/ap/ieee802_11.c +++ b/src/ap/ieee802_11.c @@ -2297,28 +2297,30 @@ static u16 check_multi_ap(struct hostapd_data *hapd, struct sta_info *sta, } } - if (multi_ap_value == MULTI_AP_BACKHAUL_STA) - sta->flags |= WLAN_STA_MULTI_AP; + if (multi_ap_value && multi_ap_value != MULTI_AP_BACKHAUL_STA) + hostapd_logger(hapd, sta->addr, HOSTAPD_MODULE_IEEE80211, + HOSTAPD_LEVEL_INFO, + "Multi-AP IE with unexpected value 0x%02x", + multi_ap_value); - if ((hapd->conf->multi_ap & BACKHAUL_BSS) && - multi_ap_value == MULTI_AP_BACKHAUL_STA) - return WLAN_STATUS_SUCCESS; + if (!(multi_ap_value & MULTI_AP_BACKHAUL_STA)) { + if (hapd->conf->multi_ap & FRONTHAUL_BSS) + return WLAN_STATUS_SUCCESS; - if (hapd->conf->multi_ap & FRONTHAUL_BSS) { - if (multi_ap_value == MULTI_AP_BACKHAUL_STA) { - hostapd_logger(hapd, sta->addr, - HOSTAPD_MODULE_IEEE80211, - HOSTAPD_LEVEL_INFO, - "Backhaul STA tries to associate with fronthaul-only BSS"); - return WLAN_STATUS_ASSOC_DENIED_UNSPEC; - } - return WLAN_STATUS_SUCCESS; + hostapd_logger(hapd, sta->addr, + HOSTAPD_MODULE_IEEE80211, + HOSTAPD_LEVEL_INFO, + "Non-Multi-AP STA tries to associate with backhaul-only BSS"); + return WLAN_STATUS_ASSOC_DENIED_UNSPEC; } - hostapd_logger(hapd, sta->addr, HOSTAPD_MODULE_IEEE80211, - HOSTAPD_LEVEL_INFO, - "Non-Multi-AP STA tries to associate with backhaul-only BSS"); - return WLAN_STATUS_ASSOC_DENIED_UNSPEC; + if (!(hapd->conf->multi_ap & BACKHAUL_BSS)) + hostapd_logger(hapd, sta->addr, HOSTAPD_MODULE_IEEE80211, + HOSTAPD_LEVEL_DEBUG, + "Backhaul STA tries to associate with fronthaul-only BSS"); + + sta->flags |= WLAN_STA_MULTI_AP; + return WLAN_STATUS_SUCCESS; }