From: Jouni Malinen jouni@codeaurora.org
commit 3e493173b7841259a08c5c8e5cbe90adb349da7e upstream.
The Layer 2 Update frame is used to update bridges when a station roams to another AP even if that STA does not transmit any frames after the reassociation. This behavior was described in IEEE Std 802.11F-2003 as something that would happen based on MLME-ASSOCIATE.indication, i.e., before completing 4-way handshake. However, this IEEE trial-use recommended practice document was published before RSN (IEEE Std 802.11i-2004) and as such, did not consider RSN use cases. Furthermore, IEEE Std 802.11F-2003 was withdrawn in 2006 and as such, has not been maintained amd should not be used anymore.
Sending out the Layer 2 Update frame immediately after association is fine for open networks (and also when using SAE, FT protocol, or FILS authentication when the station is actually authenticated by the time association completes). However, it is not appropriate for cases where RSN is used with PSK or EAP authentication since the station is actually fully authenticated only once the 4-way handshake completes after authentication and attackers might be able to use the unauthenticated triggering of Layer 2 Update frame transmission to disrupt bridge behavior.
Fix this by postponing transmission of the Layer 2 Update frame from station entry addition to the point when the station entry is marked authorized. Similarly, send out the VLAN binding update only if the STA entry has already been authorized.
Signed-off-by: Jouni Malinen jouni@codeaurora.org Reviewed-by: Johannes Berg johannes@sipsolutions.net Signed-off-by: David S. Miller davem@davemloft.net [bwh: Backported to 4.9: adjust context] Signed-off-by: Ben Hutchings ben.hutchings@codethink.co.uk Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- net/mac80211/cfg.c | 11 +++-------- net/mac80211/sta_info.c | 4 ++++ 2 files changed, 7 insertions(+), 8 deletions(-)
--- a/net/mac80211/cfg.c +++ b/net/mac80211/cfg.c @@ -1357,7 +1357,6 @@ static int ieee80211_add_station(struct struct sta_info *sta; struct ieee80211_sub_if_data *sdata; int err; - int layer2_update;
if (params->vlan) { sdata = IEEE80211_DEV_TO_SUB_IF(params->vlan); @@ -1401,18 +1400,12 @@ static int ieee80211_add_station(struct test_sta_flag(sta, WLAN_STA_ASSOC)) rate_control_rate_init(sta);
- layer2_update = sdata->vif.type == NL80211_IFTYPE_AP_VLAN || - sdata->vif.type == NL80211_IFTYPE_AP; - err = sta_info_insert_rcu(sta); if (err) { rcu_read_unlock(); return err; }
- if (layer2_update) - cfg80211_send_layer2_update(sta->sdata->dev, sta->sta.addr); - rcu_read_unlock();
return 0; @@ -1521,7 +1514,9 @@ static int ieee80211_change_station(stru atomic_inc(&sta->sdata->bss->num_mcast_sta); }
- cfg80211_send_layer2_update(sta->sdata->dev, sta->sta.addr); + if (sta->sta_state == IEEE80211_STA_AUTHORIZED) + cfg80211_send_layer2_update(sta->sdata->dev, + sta->sta.addr); }
err = sta_apply_parameters(local, sta, params); --- a/net/mac80211/sta_info.c +++ b/net/mac80211/sta_info.c @@ -1896,6 +1896,10 @@ int sta_info_move_state(struct sta_info ieee80211_check_fast_xmit(sta); ieee80211_check_fast_rx(sta); } + if (sta->sdata->vif.type == NL80211_IFTYPE_AP_VLAN || + sta->sdata->vif.type == NL80211_IFTYPE_AP) + cfg80211_send_layer2_update(sta->sdata->dev, + sta->sta.addr); break; default: break;