cfg80211: release station info tidstats where needed

This fixes memory leaks in cases where we got the station
info but failed sending it out properly.

Fixes: 8689c051 ("cfg80211: dynamically allocate per-tid stats for station info")
Reviewed-by: NArend van Spriel <arend.vanspriel@broadcom.com>
Signed-off-by: NJohannes Berg <johannes.berg@intel.com>

include/net/cfg80211.h

@@ -5710,6 +5710,19 @@ void cfg80211_remain_on_channel_expired(struct wireless_dev *wdev, u64 cookie,
  */
 int cfg80211_sinfo_alloc_tid_stats(struct station_info *sinfo, gfp_t gfp);
 
+/**
+ * cfg80211_sinfo_release_content - release contents of station info
+ * @sinfo: the station information
+ *
+ * Releases any potentially allocated sub-information of the station
+ * information, but not the struct itself (since it's typically on
+ * the stack.)
+ */
+static inline void cfg80211_sinfo_release_content(struct station_info *sinfo)
+{
+	kfree(sinfo->pertid);
+}
+
 /**
  * cfg80211_new_sta - notify userspace about station
  *

net/wireless/nl80211.c

@@ -4702,7 +4702,6 @@ static int nl80211_send_station(struct sk_buff *msg, u32 cmd, u32 portid,
 		}
 
 		nla_nest_end(msg, tidsattr);
-		kfree(sinfo->pertid);
 	}
 
 	nla_nest_end(msg, sinfoattr);
@@ -4712,10 +4711,12 @@ static int nl80211_send_station(struct sk_buff *msg, u32 cmd, u32 portid,
 		    sinfo->assoc_req_ies))
 		goto nla_put_failure;
 
+	cfg80211_sinfo_release_content(sinfo);
 	genlmsg_end(msg, hdr);
 	return 0;
 
  nla_put_failure:
+	cfg80211_sinfo_release_content(sinfo);
 	genlmsg_cancel(msg, hdr);
 	return -EMSGSIZE;
 }
@@ -4797,8 +4798,10 @@ static int nl80211_get_station(struct sk_buff *skb, struct genl_info *info)
 		return err;
 
 	msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
-	if (!msg)
+	if (!msg) {
+		cfg80211_sinfo_release_content(sinfo);
 		return -ENOMEM;
+	}
 
 	if (nl80211_send_station(msg, NL80211_CMD_NEW_STATION,
 				 info->snd_portid, info->snd_seq, 0,
@@ -14624,8 +14627,10 @@ void cfg80211_del_sta_sinfo(struct net_device *dev, const u8 *mac_addr,
 	trace_cfg80211_del_sta(dev, mac_addr);
 
 	msg = nlmsg_new(NLMSG_DEFAULT_SIZE, gfp);
-	if (!msg)
+	if (!msg) {
+		cfg80211_sinfo_release_content(sinfo);
 		return;
+	}
 
 	if (nl80211_send_station(msg, NL80211_CMD_DEL_STATION, 0, 0, 0,
 				 rdev, dev, mac_addr, sinfo) < 0) {