From: Johannes Berg Date: Wed, 5 Oct 2016 08:14:42 +0000 (+0200) Subject: mac80211: discard multicast and 4-addr A-MSDUs X-Git-Tag: v3.2.85~83 X-Git-Url: https://git.openpandora.org/cgi-bin/gitweb.cgi?p=pandora-kernel.git;a=commitdiff_plain;h=53718b139b546cdd8bd904b02690e30640172d07 mac80211: discard multicast and 4-addr A-MSDUs commit ea720935cf6686f72def9d322298bf7e9bd53377 upstream. In mac80211, multicast A-MSDUs are accepted in many cases that they shouldn't be accepted in: * drop A-MSDUs with a multicast A1 (RA), as required by the spec in 9.11 (802.11-2012 version) * drop A-MSDUs with a 4-addr header, since the fourth address can't actually be useful for them; unless 4-address frame format is actually requested, even though the fourth address is still not useful in this case, but ignored Accepting the first case, in particular, is very problematic since it allows anyone else with possession of a GTK to send unicast frames encapsulated in a multicast A-MSDU, even when the AP has client isolation enabled. Signed-off-by: Johannes Berg Signed-off-by: Ben Hutchings --- diff --git a/net/mac80211/rx.c b/net/mac80211/rx.c index 7c53effb6eda..c1d02d860489 100644 --- a/net/mac80211/rx.c +++ b/net/mac80211/rx.c @@ -1854,16 +1854,22 @@ ieee80211_rx_h_amsdu(struct ieee80211_rx_data *rx) if (!(status->rx_flags & IEEE80211_RX_AMSDU)) return RX_CONTINUE; - if (ieee80211_has_a4(hdr->frame_control) && - rx->sdata->vif.type == NL80211_IFTYPE_AP_VLAN && - !rx->sdata->u.vlan.sta) - return RX_DROP_UNUSABLE; + if (unlikely(ieee80211_has_a4(hdr->frame_control))) { + switch (rx->sdata->vif.type) { + case NL80211_IFTYPE_AP_VLAN: + if (!rx->sdata->u.vlan.sta) + return RX_DROP_UNUSABLE; + break; + case NL80211_IFTYPE_STATION: + if (!rx->sdata->u.mgd.use_4addr) + return RX_DROP_UNUSABLE; + break; + default: + return RX_DROP_UNUSABLE; + } + } - if (is_multicast_ether_addr(hdr->addr1) && - ((rx->sdata->vif.type == NL80211_IFTYPE_AP_VLAN && - rx->sdata->u.vlan.sta) || - (rx->sdata->vif.type == NL80211_IFTYPE_STATION && - rx->sdata->u.mgd.use_4addr))) + if (is_multicast_ether_addr(hdr->addr1)) return RX_DROP_UNUSABLE; skb->dev = dev;