From ff767a758086cac8797e611d3c5e9210a563a83b Mon Sep 17 00:00:00 2001
From: antirez <antirez@gmail.com>
Date: Mon, 29 Mar 2010 12:33:41 +0200
Subject: [PATCH] free hash table entries about no longer active classes, so
 that PUBSUB can be abused with millions of different classes

---
 redis.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/redis.c b/redis.c
index 6e450aaf..650e11e4 100644
--- a/redis.c
+++ b/redis.c
@@ -9312,6 +9312,12 @@ static int pubsubUnsubscribe(redisClient *c, robj *class, int notify) {
         ln = listSearchKey(clients,c);
         assert(ln != NULL);
         listDelNode(clients,ln);
+        if (listLength(clients) == 0) {
+            /* Free the list and associated hash entry at all if this was
+             * the latest client, so that it will be possible to abuse
+             * Redis PUBSUB creating millions of classes. */
+            dictDelete(server.pubsub_classes,class);
+        }
     }
     /* Notify the client */
     if (notify) {
-- 
2.45.2