Merge remote-tracking branch 'asoc/fix/cs42l52' into tmp

[cascardo/linux.git] / net / netfilter / xt_hashlimit.c

diff --git a/net/netfilter/xt_hashlimit.c b/net/netfilter/xt_hashlimit.c
index 26a668a..a9d7af9 100644 (file)
--- a/net/netfilter/xt_hashlimit.c
+++ b/net/netfilter/xt_hashlimit.c
@@ -157,11 +157,22 @@ dsthash_find(const struct xt_hashlimit_htable *ht,
 /* allocate dsthash_ent, initialize dst, put in htable and lock it */
 static struct dsthash_ent *
 dsthash_alloc_init(struct xt_hashlimit_htable *ht,
-                  const struct dsthash_dst *dst)
+                  const struct dsthash_dst *dst, bool *race)
 {
        struct dsthash_ent *ent;
 
        spin_lock(&ht->lock);
+
+       /* Two or more packets may race to create the same entry in the
+        * hashtable, double check if this packet lost race.
+        */
+       ent = dsthash_find(ht, dst);
+       if (ent != NULL) {
+               spin_unlock(&ht->lock);
+               *race = true;
+               return ent;
+       }
+
        /* initialize hash with random val at the time we allocate
         * the first hashtable entry */
        if (unlikely(!ht->rnd_initialized)) {
@@ -318,7 +329,10 @@ static void htable_destroy(struct xt_hashlimit_htable *hinfo)
                parent = hashlimit_net->ipt_hashlimit;
        else
                parent = hashlimit_net->ip6t_hashlimit;
-       remove_proc_entry(hinfo->pde->name, parent);
+
+       if(parent != NULL)
+               remove_proc_entry(hinfo->pde->name, parent);
+
        htable_selective_cleanup(hinfo, select_all);
        vfree(hinfo);
 }
@@ -585,6 +599,7 @@ hashlimit_mt(const struct sk_buff *skb, struct xt_action_param *par)
        unsigned long now = jiffies;
        struct dsthash_ent *dh;
        struct dsthash_dst dst;
+       bool race = false;
        u32 cost;
 
        if (hashlimit_init_dst(hinfo, &dst, skb, par->thoff) < 0)
@@ -593,13 +608,18 @@ hashlimit_mt(const struct sk_buff *skb, struct xt_action_param *par)
        rcu_read_lock_bh();
        dh = dsthash_find(hinfo, &dst);
        if (dh == NULL) {
-               dh = dsthash_alloc_init(hinfo, &dst);
+               dh = dsthash_alloc_init(hinfo, &dst, &race);
                if (dh == NULL) {
                        rcu_read_unlock_bh();
                        goto hotdrop;
+               } else if (race) {
+                       /* Already got an entry, update expiration timeout */
+                       dh->expires = now + msecs_to_jiffies(hinfo->cfg.expire);
+                       rateinfo_recalc(dh, now, hinfo->cfg.mode);
+               } else {
+                       dh->expires = jiffies + msecs_to_jiffies(hinfo->cfg.expire);
+                       rateinfo_init(dh, hinfo);
                }
-               dh->expires = jiffies + msecs_to_jiffies(hinfo->cfg.expire);
-               rateinfo_init(dh, hinfo);
        } else {
                /* update expiration timeout */
                dh->expires = now + msecs_to_jiffies(hinfo->cfg.expire);
@@ -856,6 +876,27 @@ static int __net_init hashlimit_proc_net_init(struct net *net)
 
 static void __net_exit hashlimit_proc_net_exit(struct net *net)
 {
+       struct xt_hashlimit_htable *hinfo;
+       struct hlist_node *pos;
+       struct proc_dir_entry *pde;
+       struct hashlimit_net *hashlimit_net = hashlimit_pernet(net);
+
+       /* recent_net_exit() is called before recent_mt_destroy(). Make sure
+        * that the parent xt_recent proc entry is is empty before trying to
+        * remove it.
+        */
+       mutex_lock(&hashlimit_mutex);
+       pde = hashlimit_net->ipt_hashlimit;
+       if (pde == NULL)
+               pde = hashlimit_net->ip6t_hashlimit;
+
+       hlist_for_each_entry(hinfo, pos, &hashlimit_net->htables, node)
+               remove_proc_entry(hinfo->pde->name, pde);
+
+       hashlimit_net->ipt_hashlimit = NULL;
+       hashlimit_net->ip6t_hashlimit = NULL;
+       mutex_unlock(&hashlimit_mutex);
+
        proc_net_remove(net, "ipt_hashlimit");
 #if IS_ENABLED(CONFIG_IP6_NF_IPTABLES)
        proc_net_remove(net, "ip6t_hashlimit");
@@ -872,9 +913,6 @@ static int __net_init hashlimit_net_init(struct net *net)
 
 static void __net_exit hashlimit_net_exit(struct net *net)
 {
-       struct hashlimit_net *hashlimit_net = hashlimit_pernet(net);
-
-       BUG_ON(!hlist_empty(&hashlimit_net->htables));
        hashlimit_proc_net_exit(net);
 }