| Message ID | 1501221784-18226-1-git-send-email-xiaolou4617@gmail.com |
|---|---|
| State | Changes Requested |
| Delegated to: | Pablo Neira |
| Headers | show |
On Fri, Jul 28, 2017 at 02:03:04PM +0800, Lin Zhang wrote: > In function {ipv4,ipv6}_synproxy_hook we expect a normal tcp packet, > but the real server maybe reply an icmp error packet related to the > exist tcp conntrack, so we will access wrong tcp data. > > For fix it, we simply pass IP_CT_RELATED_REPLY packets. > > Signed-off-by: Lin Zhang <xiaolou4617@gmail.com> > --- > net/ipv4/netfilter/ipt_SYNPROXY.c | 2 +- > net/ipv6/netfilter/ip6t_SYNPROXY.c | 2 +- > 2 files changed, 2 insertions(+), 2 deletions(-) > > diff --git a/net/ipv4/netfilter/ipt_SYNPROXY.c b/net/ipv4/netfilter/ipt_SYNPROXY.c > index f1528f7..3971fd9 100644 > --- a/net/ipv4/netfilter/ipt_SYNPROXY.c > +++ b/net/ipv4/netfilter/ipt_SYNPROXY.c > @@ -330,7 +330,7 @@ static unsigned int ipv4_synproxy_hook(void *priv, > if (synproxy == NULL) > return NF_ACCEPT; > > - if (nf_is_loopback_packet(skb)) > + if (nf_is_loopback_packet(skb) || ctinfo == IP_CT_RELATED_REPLY) If the intention is to inspect TCP traffic only, I would suggest you just check for the protocol field here instead. So we are sure we only deal with TCP traffic indeed. Thanks. -- To unsubscribe from this list: send the line "unsubscribe netfilter-devel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/net/ipv4/netfilter/ipt_SYNPROXY.c b/net/ipv4/netfilter/ipt_SYNPROXY.c index f1528f7..3971fd9 100644 --- a/net/ipv4/netfilter/ipt_SYNPROXY.c +++ b/net/ipv4/netfilter/ipt_SYNPROXY.c @@ -330,7 +330,7 @@ static unsigned int ipv4_synproxy_hook(void *priv, if (synproxy == NULL) return NF_ACCEPT; - if (nf_is_loopback_packet(skb)) + if (nf_is_loopback_packet(skb) || ctinfo == IP_CT_RELATED_REPLY) return NF_ACCEPT; thoff = ip_hdrlen(skb); diff --git a/net/ipv6/netfilter/ip6t_SYNPROXY.c b/net/ipv6/netfilter/ip6t_SYNPROXY.c index ce203dd..c4bcefe 100644 --- a/net/ipv6/netfilter/ip6t_SYNPROXY.c +++ b/net/ipv6/netfilter/ip6t_SYNPROXY.c @@ -347,7 +347,7 @@ static unsigned int ipv6_synproxy_hook(void *priv, if (synproxy == NULL) return NF_ACCEPT; - if (nf_is_loopback_packet(skb)) + if (nf_is_loopback_packet(skb) || ctinfo == IP_CT_RELATED_REPLY) return NF_ACCEPT; nexthdr = ipv6_hdr(skb)->nexthdr;
In function {ipv4,ipv6}_synproxy_hook we expect a normal tcp packet, but the real server maybe reply an icmp error packet related to the exist tcp conntrack, so we will access wrong tcp data. For fix it, we simply pass IP_CT_RELATED_REPLY packets. Signed-off-by: Lin Zhang <xiaolou4617@gmail.com> --- net/ipv4/netfilter/ipt_SYNPROXY.c | 2 +- net/ipv6/netfilter/ip6t_SYNPROXY.c | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-)