[RFC,v2] mac80211: fix possible null-pointer dereference

Commit Message

Christian Lamparter Sept. 24, 2010, 10:02 p.m. UTC

None

Patch

diff --git a/net/mac80211/mesh_plink.c b/net/mac80211/mesh_plink.c
index ea13a80..8b7efee 100644
--- a/net/mac80211/mesh_plink.c
+++ b/net/mac80211/mesh_plink.c
@@ -412,7 +412,7 @@  void mesh_rx_plink_frame(struct ieee80211_sub_if_data *sdata, struct ieee80211_m
 	enum plink_event event;
 	enum plink_frame_type ftype;
 	size_t baselen;
-	bool deactivated;
+	bool deactivated, matches_local = true;
 	u8 ie_len;
 	u8 *baseaddr;
 	__le16 plid, llid, reason;
@@ -487,6 +487,7 @@  void mesh_rx_plink_frame(struct ieee80211_sub_if_data *sdata, struct ieee80211_m
 	/* Now we will figure out the appropriate event... */
 	event = PLINK_UNDEFINED;
 	if (ftype != PLINK_CLOSE && (!mesh_matches_local(&elems, sdata))) {
+		matches_local = false;
 		switch (ftype) {
 		case PLINK_OPEN:
 			event = OPN_RJCT;
@@ -498,7 +499,15 @@  void mesh_rx_plink_frame(struct ieee80211_sub_if_data *sdata, struct ieee80211_m
 			/* avoid warning */
 			break;
 		}
-		spin_lock_bh(&sta->lock);
+	}
+
+	if (!sta && !matches_local) {
+		rcu_read_unlock();
+		reason = cpu_to_le16(MESH_CAPABILITY_POLICY_VIOLATION);
+		llid = 0;
+		mesh_plink_frame_tx(sdata, PLINK_CLOSE, mgmt->sa, llid,
+ 				    plid, reason);
+		return;
 	} else if (!sta) {
 		/* ftype == PLINK_OPEN */
 		u32 rates;
@@ -522,7 +531,7 @@  void mesh_rx_plink_frame(struct ieee80211_sub_if_data *sdata, struct ieee80211_m
 		}
 		event = OPN_ACPT;
 		spin_lock_bh(&sta->lock);
-	} else {
+	} else if (matches_local) {
 		spin_lock_bh(&sta->lock);
 		switch (ftype) {
 		case PLINK_OPEN:
@@ -564,6 +573,8 @@  void mesh_rx_plink_frame(struct ieee80211_sub_if_data *sdata, struct ieee80211_m
 			rcu_read_unlock();
 			return;
 		}
+	} else {
+		spin_lock_bh(&sta->lock);
 	}
 
 	mpl_dbg("Mesh plink (peer, state, llid, plid, event): %pM %s %d %d %d\n",