netfilter: xt_CT: fix refcnt leak on error path

There are two cases which causes refcnt leak.

1. When nf_ct_timeout_ext_add failed in xt_ct_set_timeout, it should
free the timeout refcnt.
Now goto the err_put_timeout error handler instead of going ahead.

2. When the time policy is not found, we should call module_put.
Otherwise, the related cthelper module cannot be removed anymore.
It is easy to reproduce by typing the following command:
  # iptables -t raw -A OUTPUT -p tcp -j CT --helper ftp --timeout xxx

Signed-off-by: Gao Feng <fgao@ikuai8.com>
Signed-off-by: Liping Zhang <zlpnobody@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

diff --git a/net/netfilter/xt_CT.c b/net/netfilter/xt_CT.c
index b008db0184b8a2a1679d5d4737427a672c36b560..81fdcdca74576323b73b892091556842b9725edd 100644 (file)
--- a/net/netfilter/xt_CT.c
+++ b/net/netfilter/xt_CT.c
@@ -167,8 +167,10 @@ xt_ct_set_timeout(struct nf_conn *ct, const struct xt_tgchk_param *par,
                goto err_put_timeout;
        }
        timeout_ext = nf_ct_timeout_ext_add(ct, timeout, GFP_ATOMIC);
-       if (timeout_ext == NULL)
+       if (!timeout_ext) {
                ret = -ENOMEM;
+               goto err_put_timeout;
+       }
 
        rcu_read_unlock();
        return ret;
@@ -200,6 +202,7 @@ static int xt_ct_tg_check(const struct xt_tgchk_param *par,
                          struct xt_ct_target_info_v1 *info)
 {
        struct nf_conntrack_zone zone;
+       struct nf_conn_help *help;
        struct nf_conn *ct;
        int ret = -EOPNOTSUPP;
 
@@ -248,7 +251,7 @@ static int xt_ct_tg_check(const struct xt_tgchk_param *par,
        if (info->timeout[0]) {
                ret = xt_ct_set_timeout(ct, par, info->timeout);
                if (ret < 0)
-                       goto err3;
+                       goto err4;
        }
        __set_bit(IPS_CONFIRMED_BIT, &ct->status);
        nf_conntrack_get(&ct->ct_general);
@@ -256,6 +259,10 @@ out:
        info->ct = ct;
        return 0;
 
+err4:
+       help = nfct_help(ct);
+       if (help)
+               module_put(help->helper->me);
 err3:
        nf_ct_tmpl_free(ct);
 err2: