[PATCH 1/2] wifi: mac80211: flush queues on STA removal

[PATCH 1/2] wifi: mac80211: flush queues on STA removal

[Johannes Berg]

From: Johannes Berg <johannes.berg@intel.com>

When we remove a station, we first make it unreachable,
then we (must) remove its keys, and then remove the
station itself. Depending on the hardware design, if
we have hardware crypto at all, frames still sitting
on hardware queues may then be transmitted without a
valid key, possibly unencrypted or with a fixed key.

Fix this by flushing the queues when removing stations
so this cannot happen.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
---
 net/mac80211/sta_info.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/net/mac80211/sta_info.c b/net/mac80211/sta_info.c
index 941bda9141fa..ce7c3b997269 100644
--- a/net/mac80211/sta_info.c
+++ b/net/mac80211/sta_info.c
@@ -1294,6 +1294,14 @@ static void __sta_info_destroy_part2(struct sta_info *sta)
 		WARN_ON_ONCE(ret);
 	}
 
+	/* Flush queues before removing keys, as that might remove them
+	 * from hardware, and then depending on the offload method, any
+	 * frames sitting on hardware queues might be sent out without
+	 * any encryption at all.
+	 */
+	if (local->ops->set_key)
+		ieee80211_flush_queues(local, sta->sdata, false);
+
 	/* now keys can no longer be reached */
 	ieee80211_free_sta_keys(local, sta);
 
-- 
2.39.2

[PATCH 2/2] wifi: mac80211: add flush_sta method

[Johannes Berg]

From: Johannes Berg <johannes.berg@intel.com>

Some drivers like iwlwifi might have per-STA queues, so we
may want to flush/drop just those queues rather than all
when removing a station. Add a separate method for that.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
---
 include/net/mac80211.h    |  6 ++++++
 net/mac80211/driver-ops.h | 15 +++++++++++++++
 net/mac80211/sta_info.c   |  8 ++++++--
 net/mac80211/trace.h      |  7 +++++++
 4 files changed, 34 insertions(+), 2 deletions(-)

diff --git a/include/net/mac80211.h b/include/net/mac80211.h
index 679421d37a42..a8dadbd83d95 100644
--- a/include/net/mac80211.h
+++ b/include/net/mac80211.h
@@ -3950,6 +3950,10 @@ struct ieee80211_prep_tx_info {
  *	Note that vif can be NULL.
  *	The callback can sleep.
  *
+ * @flush_sta: Flush or drop all pending frames from the hardware queue(s) for
+ *	the given station, as it's about to be removed.
+ *	The callback can sleep.
+ *
  * @channel_switch: Drivers that need (or want) to offload the channel
  *	switch operation for CSAs received from the AP may implement this
  *	callback. They must then call ieee80211_chswitch_done() to indicate
@@ -4415,6 +4419,8 @@ struct ieee80211_ops {
 #endif
 	void (*flush)(struct ieee80211_hw *hw, struct ieee80211_vif *vif,
 		      u32 queues, bool drop);
+	void (*flush_sta)(struct ieee80211_hw *hw, struct ieee80211_vif *vif,
+			  struct ieee80211_sta *sta);
 	void (*channel_switch)(struct ieee80211_hw *hw,
 			       struct ieee80211_vif *vif,
 			       struct ieee80211_channel_switch *ch_switch);
diff --git a/net/mac80211/driver-ops.h b/net/mac80211/driver-ops.h
index 0bf208f5bbc5..45d3e53c7383 100644
--- a/net/mac80211/driver-ops.h
+++ b/net/mac80211/driver-ops.h
@@ -649,6 +649,21 @@ static inline void drv_flush(struct ieee80211_local *local,
 	trace_drv_return_void(local);
 }
 
+static inline void drv_flush_sta(struct ieee80211_local *local,
+				 struct ieee80211_sub_if_data *sdata,
+				 struct sta_info *sta)
+{
+	might_sleep();
+
+	if (sdata && !check_sdata_in_driver(sdata))
+		return;
+
+	trace_drv_flush_sta(local, sdata, &sta->sta);
+	if (local->ops->flush_sta)
+		local->ops->flush_sta(&local->hw, &sdata->vif, &sta->sta);
+	trace_drv_return_void(local);
+}
+
 static inline void drv_channel_switch(struct ieee80211_local *local,
 				      struct ieee80211_sub_if_data *sdata,
 				      struct ieee80211_channel_switch *ch_switch)
diff --git a/net/mac80211/sta_info.c b/net/mac80211/sta_info.c
index ce7c3b997269..1400512e0dde 100644
--- a/net/mac80211/sta_info.c
+++ b/net/mac80211/sta_info.c
@@ -1299,8 +1299,12 @@ static void __sta_info_destroy_part2(struct sta_info *sta)
 	 * frames sitting on hardware queues might be sent out without
 	 * any encryption at all.
 	 */
-	if (local->ops->set_key)
-		ieee80211_flush_queues(local, sta->sdata, false);
+	if (local->ops->set_key) {
+		if (local->ops->flush_sta)
+			drv_flush_sta(local, sta->sdata, sta);
+		else
+			ieee80211_flush_queues(local, sta->sdata, false);
+	}
 
 	/* now keys can no longer be reached */
 	ieee80211_free_sta_keys(local, sta);
diff --git a/net/mac80211/trace.h b/net/mac80211/trace.h
index e0ccf5fe708a..de5d69f21306 100644
--- a/net/mac80211/trace.h
+++ b/net/mac80211/trace.h
@@ -1177,6 +1177,13 @@ TRACE_EVENT(drv_flush,
 	)
 );
 
+DEFINE_EVENT(sta_event, drv_flush_sta,
+	TP_PROTO(struct ieee80211_local *local,
+		 struct ieee80211_sub_if_data *sdata,
+		 struct ieee80211_sta *sta),
+	TP_ARGS(local, sdata, sta)
+);
+
 TRACE_EVENT(drv_channel_switch,
 	TP_PROTO(struct ieee80211_local *local,
 		 struct ieee80211_sub_if_data *sdata,
-- 
2.39.2