netfilter: ipt_CLUSTERIP: fix refcount leak in clusterip_tg_check()

The issue takes place in one error path of clusterip_tg_check(). When
memcmp() returns nonzero, the function simply returns the error code,
forgetting to decrease the reference count of a clusterip_config
object, which is bumped earlier by clusterip_config_find_get(). This
may incur reference count leak.

Fix this issue by decrementing the refcount of the object in specific
error path.

Fixes: 06aa151ad1fc74 ("netfilter: ipt_CLUSTERIP: check MAC address when duplicate config is set")
Signed-off-by: Xin Xiong <xiongx18@fudan.edu.cn>
Signed-off-by: Xiyu Yang <xiyuyang19@fudan.edu.cn>
Signed-off-by: Xin Tan <tanxin.ctf@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

diff --git a/net/ipv4/netfilter/ipt_CLUSTERIP.c b/net/ipv4/netfilter/ipt_CLUSTERIP.c
index 8fd1aba..b518f20 100644 (file)
--- a/net/ipv4/netfilter/ipt_CLUSTERIP.c
+++ b/net/ipv4/netfilter/ipt_CLUSTERIP.c
@@ -520,8 +520,11 @@ static int clusterip_tg_check(const struct xt_tgchk_param *par)
                        if (IS_ERR(config))
                                return PTR_ERR(config);
                }
-       } else if (memcmp(&config->clustermac, &cipinfo->clustermac, ETH_ALEN))
+       } else if (memcmp(&config->clustermac, &cipinfo->clustermac, ETH_ALEN)) {
+               clusterip_config_entry_put(config);
+               clusterip_config_put(config);
                return -EINVAL;
+       }
 
        ret = nf_ct_netns_get(par->net, par->family);
        if (ret < 0) {