cfg80211: Fix possible memory leak in function cfg80211_bss_update

When we exceed the limit of BSS entries, this function will free the
new entry, however, at this time, it is the last door to access the
inputed ies, so these ies will be unreferenced objects and cause memory
leak.
Therefore we should free its ies before deallocating the new entry, beside
of dropping it from hidden_list.

Signed-off-by: Nguyen Dinh Phi <phind.uet@gmail.com>
Link: https://lore.kernel.org/r/20210628132334.851095-1-phind.uet@gmail.com
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

net/wireless/scan.c

@@ -1754,16 +1754,14 @@ cfg80211_bss_update(struct cfg80211_registered_device *rdev,
 			 * be grouped with this beacon for updates ...
 			 */
 			if (!cfg80211_combine_bsses(rdev, new)) {
-				kfree(new);
+				bss_ref_put(rdev, new);
 				goto drop;
 			}
 		}
 
 		if (rdev->bss_entries >= bss_entries_limit &&
 		    !cfg80211_bss_expire_oldest(rdev)) {
-			if (!list_empty(&new->hidden_list))
-				list_del(&new->hidden_list);
-			kfree(new);
+			bss_ref_put(rdev, new);
 			goto drop;
 		}