diff options
| author | Lin Zhang <xiaolou4617@gmail.com> | 2017-10-06 00:44:03 +0800 |
|---|---|---|
| committer | Pablo Neira Ayuso <pablo@netfilter.org> | 2017-10-09 13:08:39 +0200 |
| commit | 49f817d793d1bcc11d721881aac037b996feef5c (patch) | |
| tree | f1525ecf75e8f4e4d7c9ffca73f2b097cb4c424a | |
| parent | e466af75c074e76107ae1cd5a2823e9c61894ffb (diff) | |
| download | linux-rseq-49f817d793d1bcc11d721881aac037b996feef5c.tar.gz | |
netfilter: SYNPROXY: skip non-tcp packet in {ipv4, ipv6}_synproxy_hook
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.
Fix it by checking for the protocol field and only process tcp traffic.
Signed-off-by: Lin Zhang <xiaolou4617@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
| -rw-r--r-- | net/ipv4/netfilter/ipt_SYNPROXY.c | 3 | ||||
| -rw-r--r-- | net/ipv6/netfilter/ip6t_SYNPROXY.c | 2 |
2 files changed, 3 insertions, 2 deletions
diff --git a/net/ipv4/netfilter/ipt_SYNPROXY.c b/net/ipv4/netfilter/ipt_SYNPROXY.c index 811689e523c31..f75fc6b531152 100644 --- a/net/ipv4/netfilter/ipt_SYNPROXY.c +++ b/net/ipv4/netfilter/ipt_SYNPROXY.c @@ -330,7 +330,8 @@ 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) || + ip_hdr(skb)->protocol != IPPROTO_TCP) return NF_ACCEPT; thoff = ip_hdrlen(skb); diff --git a/net/ipv6/netfilter/ip6t_SYNPROXY.c b/net/ipv6/netfilter/ip6t_SYNPROXY.c index a5cd43d75393d..437af8c95277f 100644 --- a/net/ipv6/netfilter/ip6t_SYNPROXY.c +++ b/net/ipv6/netfilter/ip6t_SYNPROXY.c @@ -353,7 +353,7 @@ static unsigned int ipv6_synproxy_hook(void *priv, nexthdr = ipv6_hdr(skb)->nexthdr; thoff = ipv6_skip_exthdr(skb, sizeof(struct ipv6hdr), &nexthdr, &frag_off); - if (thoff < 0) + if (thoff < 0 || nexthdr != IPPROTO_TCP) return NF_ACCEPT; th = skb_header_pointer(skb, thoff, sizeof(_th), &_th); |