[NETFILTER]: nf_nat: Clears helper private area when NATing

Some helpers (eg. ftp) assume that private area in conntrack is
filled with zero. It should be cleared when helper is changed.

Signed-off-by: Yasuyuki Kozakai <yasuyuki.kozakai@toshiba.co.jp>
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/netfilter/nf_conntrack_core.c b/net/netfilter/nf_conntrack_core.c
index 94000a4c7dcf0ccbf94457086cf6c7478d4f7745..e8b5c2d7db62355981a82475b5226ab672ae4d8f 100644 (file)
--- a/net/netfilter/nf_conntrack_core.c
+++ b/net/netfilter/nf_conntrack_core.c
@@ -888,8 +888,13 @@ void nf_conntrack_alter_reply(struct nf_conn *ct,
        NF_CT_DUMP_TUPLE(newreply);
 
        ct->tuplehash[IP_CT_DIR_REPLY].tuple = *newreply;
-       if (!ct->master && help && help->expecting == 0)
-               help->helper = __nf_ct_helper_find(newreply);
+       if (!ct->master && help && help->expecting == 0) {
+               struct nf_conntrack_helper *helper;
+               helper = __nf_ct_helper_find(newreply);
+               if (helper)
+                       memset(&help->help, 0, sizeof(help->help));
+               help->helper = helper;
+       }
        write_unlock_bh(&nf_conntrack_lock);
 }
 EXPORT_SYMBOL_GPL(nf_conntrack_alter_reply);