Patch "netfilter: xt_CT: fix refcnt leak on error path" has been added to the 4.9-stable tree

This is a note to let you know that I've just added the patch titled

netfilter: xt_CT: fix refcnt leak on error path

to the 4.9-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
netfilter-xt_ct-fix-refcnt-leak-on-error-path.patch
and it can be found in the queue-4.9 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Gao Feng <[email protected]>
Date: Fri, 14 Apr 2017 10:00:08 +0800
Subject: netfilter: xt_CT: fix refcnt leak on error path

From: Gao Feng <[email protected]>

[ Upstream commit 470acf55a021713869b9bcc967268ac90c8a0fac ]

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

---
 net/netfilter/xt_CT.c |   11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

@@ -168,8 +168,10 @@ xt_ct_set_timeout(struct nf_conn *ct, co
 		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;

@@ -201,6 +203,7 @@ static int xt_ct_tg_check(const struct x
 			  struct xt_ct_target_info_v1 *info)
 {
 	struct nf_conntrack_zone zone;
+	struct nf_conn_help *help;
 	struct nf_conn *ct;
 	int ret = -EOPNOTSUPP;
 

@@ -249,7 +252,7 @@ static int xt_ct_tg_check(const struct x
 	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);

@@ -257,6 +260,10 @@ 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:

Patches currently in stable-queue which might be from [email protected] are

queue-4.9/netfilter-xt_ct-fix-refcnt-leak-on-error-path.patch