summaryrefslogtreecommitdiff
path: root/net/ipv4
diff options
context:
space:
mode:
authorGao Feng <fgao@ikuai8.com>2017-04-20 09:01:45 +0300
committerPablo Neira Ayuso <pablo@netfilter.org>2017-04-26 10:30:22 +0300
commit495dcb56d09ddb63afe30e799af41876c3f061cc (patch)
treea1f3b7af426436ea25763e5c8f5fe58d29c63263 /net/ipv4
parentaee12a0a3727e16fb837367c4755cb6daaf45109 (diff)
downloadlinux-495dcb56d09ddb63afe30e799af41876c3f061cc.tar.xz
netfilter: SYNPROXY: Return NF_STOLEN instead of NF_DROP during handshaking
Current SYNPROXY codes return NF_DROP during normal TCP handshaking, it is not friendly to caller. Because the nf_hook_slow would treat the NF_DROP as an error, and return -EPERM. As a result, it may cause the top caller think it meets one error. For example, the following codes are from cfv_rx_poll() err = netif_receive_skb(skb); if (unlikely(err)) { ++cfv->ndev->stats.rx_dropped; } else { ++cfv->ndev->stats.rx_packets; cfv->ndev->stats.rx_bytes += skb_len; } When SYNPROXY returns NF_DROP, then netif_receive_skb returns -EPERM. As a result, the cfv driver would treat it as an error, and increase the rx_dropped counter. So use NF_STOLEN instead of NF_DROP now because there is no error happened indeed, and free the skb directly. Signed-off-by: Gao Feng <fgao@ikuai8.com> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Diffstat (limited to 'net/ipv4')
-rw-r--r--net/ipv4/netfilter/ipt_SYNPROXY.c21
1 files changed, 14 insertions, 7 deletions
diff --git a/net/ipv4/netfilter/ipt_SYNPROXY.c b/net/ipv4/netfilter/ipt_SYNPROXY.c
index c308ee0ee0bc..af2b69b6895f 100644
--- a/net/ipv4/netfilter/ipt_SYNPROXY.c
+++ b/net/ipv4/netfilter/ipt_SYNPROXY.c
@@ -293,12 +293,16 @@ synproxy_tg4(struct sk_buff *skb, const struct xt_action_param *par)
XT_SYNPROXY_OPT_ECN);
synproxy_send_client_synack(net, skb, th, &opts);
- return NF_DROP;
-
+ consume_skb(skb);
+ return NF_STOLEN;
} else if (th->ack && !(th->fin || th->rst || th->syn)) {
/* ACK from client */
- synproxy_recv_client_ack(net, skb, th, &opts, ntohl(th->seq));
- return NF_DROP;
+ if (synproxy_recv_client_ack(net, skb, th, &opts, ntohl(th->seq))) {
+ consume_skb(skb);
+ return NF_STOLEN;
+ } else {
+ return NF_DROP;
+ }
}
return XT_CONTINUE;
@@ -367,10 +371,13 @@ static unsigned int ipv4_synproxy_hook(void *priv,
* number match the one of first SYN.
*/
if (synproxy_recv_client_ack(net, skb, th, &opts,
- ntohl(th->seq) + 1))
+ ntohl(th->seq) + 1)) {
this_cpu_inc(snet->stats->cookie_retrans);
-
- return NF_DROP;
+ consume_skb(skb);
+ return NF_STOLEN;
+ } else {
+ return NF_DROP;
+ }
}
synproxy->isn = ntohl(th->ack_seq);