2021-12-23 02:51:03

by Xin Xiong

Subject: [PATCH] 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.

Signed-off-by: Xin Xiong <[email protected]>
Signed-off-by: Xiyu Yang <[email protected]>
Signed-off-by: Xin Tan <[email protected]>
---
net/ipv4/netfilter/ipt_CLUSTERIP.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/net/ipv4/netfilter/ipt_CLUSTERIP.c b/net/ipv4/netfilter/ipt_CLUSTERIP.c
index 8fd1aba8a..b518f20c9 100644
--- 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) {
--
2.25.1

2021-12-23 13:38:44

by Florian Westphal

Subject: Re: [PATCH] netfilter: ipt_CLUSTERIP: fix refcount leak in clusterip_tg_check()

Xin Xiong <[email protected]> wrote:
> 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")

2022-01-06 09:40:27

by Pablo Neira Ayuso

Subject: Re: [PATCH] netfilter: ipt_CLUSTERIP: fix refcount leak in clusterip_tg_check()

On Thu, Dec 23, 2021 at 10:48:12AM +0800, Xin Xiong wrote:
> 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.

Applied