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authorLin Zhang <xiaolou4617@gmail.com>2017-10-06 00:44:03 +0800
committerPablo Neira Ayuso <pablo@netfilter.org>2017-10-09 13:08:39 +0200
commit49f817d793d1bcc11d721881aac037b996feef5c (patch)
treef1525ecf75e8f4e4d7c9ffca73f2b097cb4c424a /net
parente466af75c074e76107ae1cd5a2823e9c61894ffb (diff)
downloadlinux-49f817d793d1bcc11d721881aac037b996feef5c.tar.bz2
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>
Diffstat (limited to 'net')
-rw-r--r--net/ipv4/netfilter/ipt_SYNPROXY.c3
-rw-r--r--net/ipv6/netfilter/ip6t_SYNPROXY.c2
2 files changed, 3 insertions, 2 deletions
diff --git a/net/ipv4/netfilter/ipt_SYNPROXY.c b/net/ipv4/netfilter/ipt_SYNPROXY.c
index 811689e523c3..f75fc6b53115 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 a5cd43d75393..437af8c95277 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);