[PATCH AUTOSEL for 4.4 043/101] netfilter: xt_CT: fix refcnt leak on error path

Sasha Levin
2018-03-08T05:06:01Z

From: Gao Feng <fgao@ikuai8.com>

[ 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

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>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
---
net/netfilter/xt_CT.c | 11 +++++++++--
1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/net/netfilter/xt_CT.c b/net/netfilter/xt_CT.c
index e7ac07e53b59..febcfac7e3df 100644
--- a/net/netfilter/xt_CT.c
+++ b/net/netfilter/xt_CT.c
@@ -168,8 +168,10 @@ 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;
@@ -201,6 +203,7 @@ 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;

@@ -249,7 +252,7 @@ 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);
@@ -257,6 +260,10 @@ static int xt_ct_tg_check(const struct xt_tgchk_param *par,
info->ct = ct;
return 0;

+err4:
+ help = nfct_help(ct);
+ if (help)
+ module_put(help->helper->me);
err3:
nf_ct_tmpl_free(ct);
err2:
--
2.14.1