ath9k_htc: properly set MAC address and BSSID mask

Pick the MAC address of the first virtual interface as the new hardware MAC
address. Set BSSID mask according to this MAC address. This fixes CVE-2013-4579.

Signed-off-by: Mathy Vanhoef <vanhoefm@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

drivers/net/wireless/ath/ath9k/htc_drv_main.c

@@ -127,21 +127,26 @@ static void ath9k_htc_bssid_iter(void *data, u8 *mac, struct ieee80211_vif *vif)
 	struct ath9k_vif_iter_data *iter_data = data;
 	int i;
 
-	for (i = 0; i < ETH_ALEN; i++)
-		iter_data->mask[i] &= ~(iter_data->hw_macaddr[i] ^ mac[i]);
+	if (iter_data->hw_macaddr != NULL) {
+		for (i = 0; i < ETH_ALEN; i++)
+			iter_data->mask[i] &= ~(iter_data->hw_macaddr[i] ^ mac[i]);
+	} else {
+		iter_data->hw_macaddr = mac;
+	}
 }
 
-static void ath9k_htc_set_bssid_mask(struct ath9k_htc_priv *priv,
+static void ath9k_htc_set_mac_bssid_mask(struct ath9k_htc_priv *priv,
 				     struct ieee80211_vif *vif)
 {
 	struct ath_common *common = ath9k_hw_common(priv->ah);
 	struct ath9k_vif_iter_data iter_data;
 
 	/*
-	 * Use the hardware MAC address as reference, the hardware uses it
-	 * together with the BSSID mask when matching addresses.
+	 * Pick the MAC address of the first interface as the new hardware
+	 * MAC address. The hardware will use it together with the BSSID mask
+	 * when matching addresses.
 	 */
-	iter_data.hw_macaddr = common->macaddr;
+	iter_data.hw_macaddr = NULL;
 	memset(&iter_data.mask, 0xff, ETH_ALEN);
 
 	if (vif)
@@ -153,6 +158,10 @@ static void ath9k_htc_set_bssid_mask(struct ath9k_htc_priv *priv,
 		ath9k_htc_bssid_iter, &iter_data);
 
 	memcpy(common->bssidmask, iter_data.mask, ETH_ALEN);
+
+	if (iter_data.hw_macaddr)
+		memcpy(common->macaddr, iter_data.hw_macaddr, ETH_ALEN);
+
 	ath_hw_setbssidmask(common);
 }
 
@@ -1063,7 +1072,7 @@ static int ath9k_htc_add_interface(struct ieee80211_hw *hw,
 		goto out;
 	}
 
-	ath9k_htc_set_bssid_mask(priv, vif);
+	ath9k_htc_set_mac_bssid_mask(priv, vif);
 
 	priv->vif_slot |= (1 << avp->index);
 	priv->nvifs++;
@@ -1128,7 +1137,7 @@ static void ath9k_htc_remove_interface(struct ieee80211_hw *hw,
 
 	ath9k_htc_set_opmode(priv);
 
-	ath9k_htc_set_bssid_mask(priv, vif);
+	ath9k_htc_set_mac_bssid_mask(priv, vif);
 
 	/*
 	 * Stop ANI only if there are no associated station interfaces.

drivers/net/wireless/ath/ath9k/main.c

@@ -965,8 +965,9 @@ void ath9k_calculate_iter_data(struct ieee80211_hw *hw,
 	struct ath_common *common = ath9k_hw_common(ah);
 
 	/*
-	 * Use the hardware MAC address as reference, the hardware uses it
-	 * together with the BSSID mask when matching addresses.
+	 * Pick the MAC address of the first interface as the new hardware
+	 * MAC address. The hardware will use it together with the BSSID mask
+	 * when matching addresses.
 	 */
 	memset(iter_data, 0, sizeof(*iter_data));
 	memset(&iter_data->mask, 0xff, ETH_ALEN);