From c317428644c0af137d80069ab178cd797da3be45 Mon Sep 17 00:00:00 2001 From: Pablo Neira Ayuso Date: Wed, 9 Feb 2011 08:08:20 +0100 Subject: [PATCH] netfilter: nf_conntrack: set conntrack templates again if we return NF_REPEAT The TCP tracking code has a special case that allows to return NF_REPEAT if we receive a new SYN packet while in TIME_WAIT state. In this situation, the TCP tracking code destroys the existing conntrack to start a new clean session. [DESTROY] tcp 6 src=192.168.0.2 dst=192.168.1.2 sport=38925 dport=8000 src=192.168.1.2 dst=192.168.1.100 sport=8000 dport=38925 [ASSURED] [NEW] tcp 6 120 SYN_SENT src=192.168.0.2 dst=192.168.1.2 sport=38925 dport=8000 [UNREPLIED] src=192.168.1.2 dst=192.168.1.100 sport=8000 dport=38925 However, this is a problem for the iptables' CT target event filtering which will not work in this case since the conntrack template will not be there for the new session. To fix this, we reassign the conntrack template to the packet if we return NF_REPEAT. Signed-off-by: Pablo Neira Ayuso Signed-off-by: Patrick McHardy --- net/netfilter/nf_conntrack_core.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) diff --git a/net/netfilter/nf_conntrack_core.c b/net/netfilter/nf_conntrack_core.c index e61511929c66..84f4fcc5884b 100644 --- a/net/netfilter/nf_conntrack_core.c +++ b/net/netfilter/nf_conntrack_core.c @@ -942,8 +942,15 @@ nf_conntrack_in(struct net *net, u_int8_t pf, unsigned int hooknum, if (set_reply && !test_and_set_bit(IPS_SEEN_REPLY_BIT, &ct->status)) nf_conntrack_event_cache(IPCT_REPLY, ct); out: - if (tmpl) - nf_ct_put(tmpl); + if (tmpl) { + /* Special case: we have to repeat this hook, assign the + * template again to this packet. We assume that this packet + * has no conntrack assigned. This is used by nf_ct_tcp. */ + if (ret == NF_REPEAT) + skb->nfct = (struct nf_conntrack *)tmpl; + else + nf_ct_put(tmpl); + } return ret; } -- 2.39.5