mac80211: allow driver to disconnect after resume

In WoWLAN, devices may use crypto keys for TX/RX
and could also implement GTK rekeying. If the
driver isn't able to retrieve replay counters and
similar information from the device upon resume,
or if the device isn't responsive due to platform
issues, it isn't safe to keep the connection up
as GTK rekey messages from during the sleep time
could be replayed against it.

The only protection against that is disconnecting
from the AP. Modifying mac80211 to do that while
it is resuming would be very complex and invasive
in the case that the driver requires a reconfig,
so do it after it has resumed completely. In that
case, however, packets might be replayed since it
can then only happen after TX/RX are up again, so
mark keys for interfaces that need to disconnect
as "tainted" and drop all packets that are sent
or received with those keys.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 27 insertions, 0 deletions

diff --git a/net/mac80211/util.c b/net/mac80211/util.c
index 1901320..5bfb80c 100644
--- a/net/mac80211/util.c
+++ b/net/mac80211/util.c
@@ -1334,6 +1334,33 @@ int ieee80211_reconfig(struct ieee80211_local *local)
 	return 0;
 }
 
+void ieee80211_resume_disconnect(struct ieee80211_vif *vif)
+{
+	struct ieee80211_sub_if_data *sdata;
+	struct ieee80211_local *local;
+	struct ieee80211_key *key;
+
+	if (WARN_ON(!vif))
+		return;
+
+	sdata = vif_to_sdata(vif);
+	local = sdata->local;
+
+	if (WARN_ON(!local->resuming))
+		return;
+
+	if (WARN_ON(vif->type != NL80211_IFTYPE_STATION))
+		return;
+
+	sdata->flags |= IEEE80211_SDATA_DISCONNECT_RESUME;
+
+	mutex_lock(&local->key_mtx);
+	list_for_each_entry(key, &sdata->key_list, list)
+		key->flags |= KEY_FLAG_TAINTED;
+	mutex_unlock(&local->key_mtx);
+}
+EXPORT_SYMBOL_GPL(ieee80211_resume_disconnect);
+
 static int check_mgd_smps(struct ieee80211_if_managed *ifmgd,
 			  enum ieee80211_smps_mode *smps_mode)
 {