2019-01-14 10:02:03

by Henry Yen (顏修溫)

Subject: [PATCH] netfilter: fix checking method of conntrack helper

This patch uses nfct_help() to detect whether an
established connection needs conntrack helper instead of using
test_bit(IPS_HELPER_BIT, &ct->status).

The reason is that IPS_HELPER_BIT is only set when using explicit
CT target.

However, in the case that a device enables conntrack helper via
command "echo 1 > /proc/sys/net/netfilter/nf_conntrack_helper",
the status of IPS_HELPER_BIT will not present any change, and
consequently it loses the checking ability in the context.

Signed-off-by: Henry Yen <[email protected]>
Reviewed-by: Ryder Lee <[email protected]>
---
net/netfilter/nft_flow_offload.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/net/netfilter/nft_flow_offload.c b/net/netfilter/nft_flow_offload.c
index 974525eb92df..de4684cc4633 100644
--- a/net/netfilter/nft_flow_offload.c
+++ b/net/netfilter/nft_flow_offload.c
@@ -12,6 +12,7 @@
#include <net/netfilter/nf_conntrack_core.h>
#include <linux/netfilter/nf_conntrack_common.h>
#include <net/netfilter/nf_flow_table.h>
+#include <net/netfilter/nf_conntrack_helper.h>

struct nft_flow_offload {
struct nft_flowtable *flowtable;
@@ -71,6 +72,7 @@ static void nft_flow_offload_eval(const struct nft_expr *expr,
struct flow_offload *flow;
enum ip_conntrack_dir dir;
struct nf_conn *ct;
+ const struct nf_conn_help *help;
int ret;

if (nft_flow_offload_skip(pkt->skb))
@@ -88,7 +90,8 @@ static void nft_flow_offload_eval(const struct nft_expr *expr,
goto out;
}

- if (test_bit(IPS_HELPER_BIT, &ct->status))
+ help = nfct_help(ct);
+ if (help)
goto out;

if (ctinfo == IP_CT_NEW ||
--
2.17.1

2019-01-14 10:38:28

by John Crispin

Subject: Re: [PATCH] netfilter: fix checking method of conntrack helper

On 14/01/2019 10:59, Henry Yen wrote:
> This patch uses nfct_help() to detect whether an
> established connection needs conntrack helper instead of using
> test_bit(IPS_HELPER_BIT, &ct->status).
>
> The reason is that IPS_HELPER_BIT is only set when using explicit
> CT target.
>
> However, in the case that a device enables conntrack helper via
> command "echo 1 > /proc/sys/net/netfilter/nf_conntrack_helper",
> the status of IPS_HELPER_BIT will not present any change, and
> consequently it loses the checking ability in the context.
>
> Signed-off-by: Henry Yen <[email protected]>
> Reviewed-by: Ryder Lee <[email protected]>
Tested-by: John Crispin <[email protected]>
> ---
> net/netfilter/nft_flow_offload.c | 5 ++++-
> 1 file changed, 4 insertions(+), 1 deletion(-)
>
> diff --git a/net/netfilter/nft_flow_offload.c b/net/netfilter/nft_flow_offload.c
> index 974525eb92df..de4684cc4633 100644
> --- a/net/netfilter/nft_flow_offload.c
> +++ b/net/netfilter/nft_flow_offload.c
> @@ -12,6 +12,7 @@
> #include <net/netfilter/nf_conntrack_core.h>
> #include <linux/netfilter/nf_conntrack_common.h>
> #include <net/netfilter/nf_flow_table.h>
> +#include <net/netfilter/nf_conntrack_helper.h>
>
> struct nft_flow_offload {
> struct nft_flowtable *flowtable;
> @@ -71,6 +72,7 @@ static void nft_flow_offload_eval(const struct nft_expr *expr,
> struct flow_offload *flow;
> enum ip_conntrack_dir dir;
> struct nf_conn *ct;
> + const struct nf_conn_help *help;
> int ret;
>
> if (nft_flow_offload_skip(pkt->skb))
> @@ -88,7 +90,8 @@ static void nft_flow_offload_eval(const struct nft_expr *expr,
> goto out;
> }
>
> - if (test_bit(IPS_HELPER_BIT, &ct->status))
> + help = nfct_help(ct);
> + if (help)
> goto out;
>
> if (ctinfo == IP_CT_NEW ||