nl80211: Add Michael MIC failure event

Define a new nl80211 event, NL80211_CMD_MICHAEL_MIC_FAILURE, to be
used to notify user space about locally detected Michael MIC failures.
This matches with the MLME-MICHAELMICFAILURE.indication() primitive.

Since we do not actually have TSC in the skb anymore when
mac80211_ev_michael_mic_failure() is called, that function is changed
to take in the TSC as an optional parameter instead of as a
requirement to include the TSC after the hdr field (which we did not
really follow). For now, TSC is not included in the events from
mac80211, but it could be added at some point.

Signed-off-by: Jouni Malinen <j@w1.fi>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

7 files changed, 67 insertions, 11 deletions

diff --git a/net/mac80211/event.c b/net/mac80211/event.c
index 0d95561..f288d01 100644
--- a/net/mac80211/event.c
+++ b/net/mac80211/event.c
@@ -12,12 +12,12 @@
 #include "ieee80211_i.h"
 
 /*
- * indicate a failed Michael MIC to userspace; the passed packet
- * (in the variable hdr) must be long enough to extract the TKIP
- * fields like TSC
+ * Indicate a failed Michael MIC to userspace. If the caller knows the TSC of
+ * the frame that generated the MIC failure (i.e., if it was provided by the
+ * driver or is still in the frame), it should provide that information.
  */
 void mac80211_ev_michael_mic_failure(struct ieee80211_sub_if_data *sdata, int keyidx,
-				     struct ieee80211_hdr *hdr)
+				     struct ieee80211_hdr *hdr, const u8 *tsc)
 {
 	union iwreq_data wrqu;
 	char *buf = kmalloc(128, GFP_ATOMIC);
@@ -34,8 +34,9 @@ void mac80211_ev_michael_mic_failure(struct ieee80211_sub_if_data *sdata, int ke
 		kfree(buf);
 	}
 
-	/*
-	 * TODO: re-add support for sending MIC failure indication
-	 * with all info via nl80211
-	 */
+	cfg80211_michael_mic_failure(sdata->dev, hdr->addr2,
+				     (hdr->addr1[0] & 0x01) ?
+				     NL80211_KEYTYPE_GROUP :
+				     NL80211_KEYTYPE_PAIRWISE,
+				     keyidx, tsc);
 }
diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h
index e6ed78c..312347d 100644
--- a/net/mac80211/ieee80211_i.h
+++ b/net/mac80211/ieee80211_i.h
@@ -1060,7 +1060,7 @@ u8 *ieee80211_get_bssid(struct ieee80211_hdr *hdr, size_t len,
 int ieee80211_frame_duration(struct ieee80211_local *local, size_t len,
 			     int rate, int erp, int short_preamble);
 void mac80211_ev_michael_mic_failure(struct ieee80211_sub_if_data *sdata, int keyidx,
-				     struct ieee80211_hdr *hdr);
+				     struct ieee80211_hdr *hdr, const u8 *tsc);
 void ieee80211_set_wmm_default(struct ieee80211_sub_if_data *sdata);
 void ieee80211_tx_skb(struct ieee80211_sub_if_data *sdata, struct sk_buff *skb,
 		      int encrypt);
diff --git a/net/mac80211/rx.c b/net/mac80211/rx.c
index 5fa7aed..19c4b45 100644
--- a/net/mac80211/rx.c
+++ b/net/mac80211/rx.c
@@ -1932,7 +1932,7 @@ static void ieee80211_rx_michael_mic_report(struct net_device *dev,
 	    !ieee80211_is_auth(hdr->frame_control))
 		goto ignore;
 
-	mac80211_ev_michael_mic_failure(rx->sdata, keyidx, hdr);
+	mac80211_ev_michael_mic_failure(rx->sdata, keyidx, hdr, NULL);
  ignore:
 	dev_kfree_skb(rx->skb);
 	rx->skb = NULL;
diff --git a/net/mac80211/wpa.c b/net/mac80211/wpa.c
index 4f8bfea..dcfae88 100644
--- a/net/mac80211/wpa.c
+++ b/net/mac80211/wpa.c
@@ -122,7 +122,7 @@ ieee80211_rx_h_michael_mic_verify(struct ieee80211_rx_data *rx)
 			return RX_DROP_UNUSABLE;
 
 		mac80211_ev_michael_mic_failure(rx->sdata, rx->key->conf.keyidx,
-						(void *) skb->data);
+						(void *) skb->data, NULL);
 		return RX_DROP_UNUSABLE;
 	}
 
diff --git a/net/wireless/mlme.c b/net/wireless/mlme.c
index 33ff7cc..1407244 100644
--- a/net/wireless/mlme.c
+++ b/net/wireless/mlme.c
@@ -43,3 +43,13 @@ void cfg80211_send_disassoc(struct net_device *dev, const u8 *buf, size_t len)
 	nl80211_send_disassoc(rdev, dev, buf, len);
 }
 EXPORT_SYMBOL(cfg80211_send_disassoc);
+
+void cfg80211_michael_mic_failure(struct net_device *dev, const u8 *addr,
+				  enum nl80211_key_type key_type, int key_id,
+				  const u8 *tsc)
+{
+	struct wiphy *wiphy = dev->ieee80211_ptr->wiphy;
+	struct cfg80211_registered_device *rdev = wiphy_to_dev(wiphy);
+	nl80211_michael_mic_failure(rdev, dev, addr, key_type, key_id, tsc);
+}
+EXPORT_SYMBOL(cfg80211_michael_mic_failure);
diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c
index 195424e..1394115 100644
--- a/net/wireless/nl80211.c
+++ b/net/wireless/nl80211.c
@@ -3430,6 +3430,46 @@ void nl80211_send_disassoc(struct cfg80211_registered_device *rdev,
 				NL80211_CMD_DISASSOCIATE);
 }
 
+void nl80211_michael_mic_failure(struct cfg80211_registered_device *rdev,
+				 struct net_device *netdev, const u8 *addr,
+				 enum nl80211_key_type key_type, int key_id,
+				 const u8 *tsc)
+{
+	struct sk_buff *msg;
+	void *hdr;
+
+	msg = nlmsg_new(NLMSG_GOODSIZE, GFP_KERNEL);
+	if (!msg)
+		return;
+
+	hdr = nl80211hdr_put(msg, 0, 0, 0, NL80211_CMD_MICHAEL_MIC_FAILURE);
+	if (!hdr) {
+		nlmsg_free(msg);
+		return;
+	}
+
+	NLA_PUT_U32(msg, NL80211_ATTR_WIPHY, rdev->wiphy_idx);
+	NLA_PUT_U32(msg, NL80211_ATTR_IFINDEX, netdev->ifindex);
+	if (addr)
+		NLA_PUT(msg, NL80211_ATTR_MAC, ETH_ALEN, addr);
+	NLA_PUT_U32(msg, NL80211_ATTR_KEY_TYPE, key_type);
+	NLA_PUT_U8(msg, NL80211_ATTR_KEY_IDX, key_id);
+	if (tsc)
+		NLA_PUT(msg, NL80211_ATTR_KEY_SEQ, 6, tsc);
+
+	if (genlmsg_end(msg, hdr) < 0) {
+		nlmsg_free(msg);
+		return;
+	}
+
+	genlmsg_multicast(msg, 0, nl80211_mlme_mcgrp.id, GFP_KERNEL);
+	return;
+
+ nla_put_failure:
+	genlmsg_cancel(msg, hdr);
+	nlmsg_free(msg);
+}
+
 /* initialisation/exit functions */
 
 int nl80211_init(void)
diff --git a/net/wireless/nl80211.h b/net/wireless/nl80211.h
index 55686fc..e4b92cc 100644
--- a/net/wireless/nl80211.h
+++ b/net/wireless/nl80211.h
@@ -23,5 +23,10 @@ extern void nl80211_send_deauth(struct cfg80211_registered_device *rdev,
 extern void nl80211_send_disassoc(struct cfg80211_registered_device *rdev,
 				  struct net_device *netdev,
 				  const u8 *buf, size_t len);
+extern void
+nl80211_michael_mic_failure(struct cfg80211_registered_device *rdev,
+			    struct net_device *netdev, const u8 *addr,
+			    enum nl80211_key_type key_type,
+			    int key_id, const u8 *tsc);
 
 #endif /* __NET_WIRELESS_NL80211_H */