cfg80211: fix wext-compat memory leak

cfg80211_wext_giwrate and sinfo.pertid might allocate sinfo.pertid via
rdev_get_station(), but never release it. Fix that.

Fixes: 8689c051a2 ("cfg80211: dynamically allocate per-tid stats for station info")
Signed-off-by: Stefan Seyfried <seife+kernel@b1-systems.com>
[johannes: fix error path, use cfg80211_sinfo_release_content(), add Fixes]
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

net/wireless/wext-compat.c

@@ -1278,12 +1278,16 @@ static int cfg80211_wext_giwrate(struct net_device *dev,
 	if (err)
 		return err;
 
-	if (!(sinfo.filled & BIT_ULL(NL80211_STA_INFO_TX_BITRATE)))
-		return -EOPNOTSUPP;
+	if (!(sinfo.filled & BIT_ULL(NL80211_STA_INFO_TX_BITRATE))) {
+		err = -EOPNOTSUPP;
+		goto free;
+	}
 
 	rate->value = 100000 * cfg80211_calculate_bitrate(&sinfo.txrate);
 
-	return 0;
+free:
+	cfg80211_sinfo_release_content(&sinfo);
+	return err;
 }
 
 /* Get wireless statistics.  Called by /proc/net/wireless and by SIOCGIWSTATS */
@@ -1293,7 +1297,7 @@ static struct iw_statistics *cfg80211_wireless_stats(struct net_device *dev)
 	struct cfg80211_registered_device *rdev = wiphy_to_rdev(wdev->wiphy);
 	/* we are under RTNL - globally locked - so can use static structs */
 	static struct iw_statistics wstats;
-	static struct station_info sinfo;
+	static struct station_info sinfo = {};
 	u8 bssid[ETH_ALEN];
 
 	if (dev->ieee80211_ptr->iftype != NL80211_IFTYPE_STATION)
@@ -1352,6 +1356,8 @@ static struct iw_statistics *cfg80211_wireless_stats(struct net_device *dev)
 	if (sinfo.filled & BIT_ULL(NL80211_STA_INFO_TX_FAILED))
 		wstats.discard.retries = sinfo.tx_failed;
 
+	cfg80211_sinfo_release_content(&sinfo);
+
 	return &wstats;
 }