netfilter: xt_recent: fix namespace destroy path

recent_net_exit() is called before recent_mt_destroy() in the
destroy path of network namespaces. Make sure there are no entries
in the parent proc entry xt_recent before removing it.

Signed-off-by: Vitaly E. Lavrov <lve@guap.ru>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

1 files changed, 16 insertions, 4 deletions

diff --git a/net/netfilter/xt_recent.c b/net/netfilter/xt_recent.c
index 4635c9b00459..dab053e2a1a2 100644
--- a/net/netfilter/xt_recent.c
+++ b/net/netfilter/xt_recent.c
@@ -431,7 +431,8 @@ static void recent_mt_destroy(const struct xt_mtdtor_param *par)
                 list_del(&t->list);
                 spin_unlock_bh(&recent_lock);
 #ifdef CONFIG_PROC_FS
-                remove_proc_entry(t->name, recent_net->xt_recent);
+                if (recent_net->xt_recent != NULL)
+                        remove_proc_entry(t->name, recent_net->xt_recent);
 #endif
                 recent_table_flush(t);
                 kfree(t);
@@ -615,6 +616,20 @@ static int __net_init recent_proc_net_init(struct net *net)
 
 static void __net_exit recent_proc_net_exit(struct net *net)
 {
+        struct recent_net *recent_net = recent_pernet(net);
+        struct recent_table *t;
+
+        /* 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.
+         */
+        spin_lock_bh(&recent_lock);
+        list_for_each_entry(t, &recent_net->tables, list)
+                remove_proc_entry(t->name, recent_net->xt_recent);
+
+        recent_net->xt_recent = NULL;
+        spin_unlock_bh(&recent_lock);
+
         proc_net_remove(net, "xt_recent");
 }
 #else
@@ -638,9 +653,6 @@ static int __net_init recent_net_init(struct net *net)
 
 static void __net_exit recent_net_exit(struct net *net)
 {
-        struct recent_net *recent_net = recent_pernet(net);
-
-        BUG_ON(!list_empty(&recent_net->tables));
         recent_proc_net_exit(net);
 }