From: Jan Engelhardt <jengelh@xxxxxxxxxx>
xt_connlimit normally records the "original" tuples in a hashlist
(such as "1.2.3.4 -> 5.6.7.8"), and looks in this list for iph->daddr
when counting.
When the user however uses DNAT in PREROUTING, looking for
iph->daddrÂ-- which is now 192.168.9.10 -- will not match. Thus in
daddr mode, we need to record the reverse direction tuple
("192.168.9.10 -> 1.2.3.4") instead. In the reverse tuple, the dst
addr is on the src side, which is convenient, as count_them still uses
&conn->tuple.src.u3.
Signed-off-by: Jan Engelhardt <jengelh@xxxxxxxxxx>
---
net/netfilter/xt_connlimit.c | 12 ++++++++----
1 files changed, 8 insertions(+), 4 deletions(-)
diff --git a/net/netfilter/xt_connlimit.c b/net/netfilter/xt_connlimit.c
index 7fd3fd5..e029c48 100644
--- a/net/netfilter/xt_connlimit.c
+++ b/net/netfilter/xt_connlimit.c
@@ -185,11 +185,15 @@ connlimit_mt(const struct sk_buff *skb, struct xt_action_param *par)
int connections;
ct = nf_ct_get(skb, &ctinfo);
- if (ct != NULL)
- tuple_ptr = &ct->tuplehash[0].tuple;
- else if (!nf_ct_get_tuplepr(skb, skb_network_offset(skb),
- par->family, &tuple))
+ if (ct != NULL) {
+ if (info->flags & XT_CONNLIMIT_DADDR)
+ tuple_ptr = &ct->tuplehash[IP_CT_DIR_REPLY].tuple;
+ else
+ tuple_ptr = &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple;
+ } else if (!nf_ct_get_tuplepr(skb, skb_network_offset(skb),
+ par->family, &tuple)) {
goto hotdrop;
+ }
if (par->family == NFPROTO_IPV6) {
const struct ipv6hdr *iph = ipv6_hdr(skb);
--
1.7.2.3
--
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