cfg80211: Unprotected Beacon frame RX indication

Extend cfg80211_rx_unprot_mlme_mgmt() to cover indication of unprotected
Beacon frames in addition to the previously used Deauthentication and
Disassociation frames. The Beacon frame case is quite similar, but has
couple of exceptions: this is used both with fully unprotected and also
incorrectly protected frames and there is a rate limit on the events to
avoid unnecessary flooding netlink events in case something goes wrong.

Signed-off-by: Jouni Malinen <jouni@codeaurora.org>
Link: https://lore.kernel.org/r/20200401142548.6990-1-jouni@codeaurora.org
[add missing kernel-doc]
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

include/net/cfg80211.h

@@ -5045,6 +5045,8 @@ struct cfg80211_cqm_config;
  * @pmsr_list: (private) peer measurement requests
  * @pmsr_lock: (private) peer measurements requests/results lock
  * @pmsr_free_wk: (private) peer measurements cleanup work
+ * @unprot_beacon_reported: (private) timestamp of last
+ *	unprotected beacon report
  */
 struct wireless_dev {
 	struct wiphy *wiphy;
@@ -5121,6 +5123,8 @@ struct wireless_dev {
 	struct list_head pmsr_list;
 	spinlock_t pmsr_lock;
 	struct work_struct pmsr_free_wk;
+
+	unsigned long unprot_beacon_reported;
 };
 
 static inline u8 *wdev_address(struct wireless_dev *wdev)
@@ -6135,12 +6139,16 @@ void cfg80211_tx_mlme_mgmt(struct net_device *dev, const u8 *buf, size_t len);
 /**
  * cfg80211_rx_unprot_mlme_mgmt - notification of unprotected mlme mgmt frame
  * @dev: network device
- * @buf: deauthentication frame (header + body)
+ * @buf: received management frame (header + body)
  * @len: length of the frame data
  *
  * This function is called whenever a received deauthentication or dissassoc
  * frame has been dropped in station mode because of MFP being used but the
- * frame was not protected. This function may sleep.
+ * frame was not protected. This is also used to notify reception of a Beacon
+ * frame that was dropped because it did not include a valid MME MIC while
+ * beacon protection was enabled (BIGTK configured in station mode).
+ *
+ * This function may sleep.
  */
 void cfg80211_rx_unprot_mlme_mgmt(struct net_device *dev,
 				  const u8 *buf, size_t len);

include/uapi/linux/nl80211.h

@@ -1151,6 +1151,11 @@
  * @NL80211_CMD_SET_TID_CONFIG: Data frame TID specific configuration
  *	is passed using %NL80211_ATTR_TID_CONFIG attribute.
  *
+ * @NL80211_CMD_UNPROT_BEACON: Unprotected or incorrectly protected Beacon
+ *	frame. This event is used to indicate that a received Beacon frame was
+ *	dropped because it did not include a valid MME MIC while beacon
+ *	protection was enabled (BIGTK configured in station mode).
+ *
  * @NL80211_CMD_MAX: highest used command number
  * @__NL80211_CMD_AFTER_LAST: internal use
  */
@@ -1377,6 +1382,8 @@ enum nl80211_commands {
 
 	NL80211_CMD_SET_TID_CONFIG,
 
+	NL80211_CMD_UNPROT_BEACON,
+
 	/* add new commands above here */
 
 	/* used to define NL80211_CMD_MAX below */

net/wireless/nl80211.c

@@ -15542,10 +15542,19 @@ void cfg80211_rx_unprot_mlme_mgmt(struct net_device *dev, const u8 *buf,
 	if (WARN_ON(len < 2))
 		return;
 
-	if (ieee80211_is_deauth(mgmt->frame_control))
+	if (ieee80211_is_deauth(mgmt->frame_control)) {
 		cmd = NL80211_CMD_UNPROT_DEAUTHENTICATE;
-	else
+	} else if (ieee80211_is_disassoc(mgmt->frame_control)) {
 		cmd = NL80211_CMD_UNPROT_DISASSOCIATE;
+	} else if (ieee80211_is_beacon(mgmt->frame_control)) {
+		if (wdev->unprot_beacon_reported &&
+		    elapsed_jiffies_msecs(wdev->unprot_beacon_reported) < 10000)
+			return;
+		cmd = NL80211_CMD_UNPROT_BEACON;
+		wdev->unprot_beacon_reported = jiffies;
+	} else {
+		return;
+	}
 
 	trace_cfg80211_rx_unprot_mlme_mgmt(dev, buf, len);
 	nl80211_send_mlme_event(rdev, dev, buf, len, cmd, GFP_ATOMIC, -1,

net/wireless/sme.c

@@ -694,6 +694,7 @@ void __cfg80211_connect_result(struct net_device *dev,
 		return;
 	}
 
+	wdev->unprot_beacon_reported = 0;
 	nl80211_send_connect_result(wiphy_to_rdev(wdev->wiphy), dev, cr,
 				    GFP_KERNEL);
 
@@ -921,6 +922,7 @@ void __cfg80211_roamed(struct wireless_dev *wdev,
 	cfg80211_hold_bss(bss_from_pub(info->bss));
 	wdev->current_bss = bss_from_pub(info->bss);
 
+	wdev->unprot_beacon_reported = 0;
 	nl80211_send_roamed(wiphy_to_rdev(wdev->wiphy),
 			    wdev->netdev, info, GFP_KERNEL);