From 7cc9eb6ef78d0dcb97d543ea19966486e98afa0b Mon Sep 17 00:00:00 2001
From: Jesper Dangaard Brouer <brouer@redhat.com>
Date: Thu, 29 Aug 2013 12:18:46 +0200
Subject: [PATCH] netfilter: SYNPROXY: let unrelated packets continue
Packets reaching SYNPROXY were default dropped, as they were most
likely invalid (given the recommended state matching). This
patch, changes SYNPROXY target to let packets, not consumed,
continue being processed by the stack.
This will be more in line other target modules. As it will allow
more flexible configurations of handling, logging or matching on
packets in INVALID states.
Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
Acked-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
---
net/ipv4/netfilter/ipt_SYNPROXY.c | 8 ++++++--
net/ipv6/netfilter/ip6t_SYNPROXY.c | 8 ++++++--
2 files changed, 12 insertions(+), 4 deletions(-)
diff --git a/net/ipv4/netfilter/ipt_SYNPROXY.c b/net/ipv4/netfilter/ipt_SYNPROXY.c
index 90e489eb1c0a..67e17dcda65e 100644
--- a/net/ipv4/netfilter/ipt_SYNPROXY.c
+++ b/net/ipv4/netfilter/ipt_SYNPROXY.c
@@ -285,11 +285,15 @@ synproxy_tg4(struct sk_buff *skb, const struct xt_action_param *par)
XT_SYNPROXY_OPT_ECN);
synproxy_send_client_synack(skb, th, &opts);
- } else if (th->ack && !(th->fin || th->rst || th->syn))
+ return NF_DROP;
+
+ } else if (th->ack && !(th->fin || th->rst || th->syn)) {
/* ACK from client */
synproxy_recv_client_ack(snet, skb, th, &opts, ntohl(th->seq));
+ return NF_DROP;
+ }
- return NF_DROP;
+ return XT_CONTINUE;
}
static unsigned int ipv4_synproxy_hook(unsigned int hooknum,
diff --git a/net/ipv6/netfilter/ip6t_SYNPROXY.c b/net/ipv6/netfilter/ip6t_SYNPROXY.c
index a5af0bfef126..19cfea8dbcaa 100644
--- a/net/ipv6/netfilter/ip6t_SYNPROXY.c
+++ b/net/ipv6/netfilter/ip6t_SYNPROXY.c
@@ -300,11 +300,15 @@ synproxy_tg6(struct sk_buff *skb, const struct xt_action_param *par)
XT_SYNPROXY_OPT_ECN);
synproxy_send_client_synack(skb, th, &opts);
- } else if (th->ack && !(th->fin || th->rst || th->syn))
+ return NF_DROP;
+
+ } else if (th->ack && !(th->fin || th->rst || th->syn)) {
/* ACK from client */
synproxy_recv_client_ack(snet, skb, th, &opts, ntohl(th->seq));
+ return NF_DROP;
+ }
- return NF_DROP;
+ return XT_CONTINUE;
}
static unsigned int ipv6_synproxy_hook(unsigned int hooknum,
--
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