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authorJulian Anastasov <ja@ssi.bg>2011-06-16 17:29:22 +0200
committerPatrick McHardy <kaber@trash.net>2011-06-16 17:29:22 +0200
commit42c1edd345c8412d96e7a362ee06feb7be73bb6c (patch)
tree5b05b0324b8186fe8bc40ffced48c856b099547d /net/ipv4
parent2c38de4c1f8da799bdca0e4bb40ca13f2174d3e8 (diff)
downloadlinux-42c1edd345c8412d96e7a362ee06feb7be73bb6c.tar.bz2
netfilter: nf_nat: avoid double seq_adjust for loopback
Avoid double seq adjustment for loopback traffic because it causes silent repetition of TCP data. One example is passive FTP with DNAT rule and difference in the length of IP addresses. This patch adds check if packet is sent and received via loopback device. As the same conntrack is used both for outgoing and incoming direction, we restrict seq adjustment to happen only in POSTROUTING. Signed-off-by: Julian Anastasov <ja@ssi.bg> Signed-off-by: Patrick McHardy <kaber@trash.net>
Diffstat (limited to 'net/ipv4')
-rw-r--r--net/ipv4/netfilter/nf_conntrack_l3proto_ipv4.c4
1 files changed, 3 insertions, 1 deletions
diff --git a/net/ipv4/netfilter/nf_conntrack_l3proto_ipv4.c b/net/ipv4/netfilter/nf_conntrack_l3proto_ipv4.c
index db10075dd88e..de9da21113a1 100644
--- a/net/ipv4/netfilter/nf_conntrack_l3proto_ipv4.c
+++ b/net/ipv4/netfilter/nf_conntrack_l3proto_ipv4.c
@@ -121,7 +121,9 @@ static unsigned int ipv4_confirm(unsigned int hooknum,
return ret;
}
- if (test_bit(IPS_SEQ_ADJUST_BIT, &ct->status)) {
+ /* adjust seqs for loopback traffic only in outgoing direction */
+ if (test_bit(IPS_SEQ_ADJUST_BIT, &ct->status) &&
+ !nf_is_loopback_packet(skb)) {
typeof(nf_nat_seq_adjust_hook) seq_adjust;
seq_adjust = rcu_dereference(nf_nat_seq_adjust_hook);