diff options
| author | Kyle Swenson <kyle.swenson@est.tech> | 2024-02-08 23:56:31 +0000 |
|---|---|---|
| committer | Pablo Neira Ayuso <pablo@netfilter.org> | 2024-02-15 00:20:00 +0100 |
| commit | 0f1ae2821fa4b13ab0f5ad7ff89fa57efcb04fe0 (patch) | |
| tree | 0f836a472f63ddd356d8bec467e2ad6f33ac9925 /net | |
| parent | f6374a82fc85bf911d033e2fa791372ce3356270 (diff) | |
netfilter: nat: restore default DNAT behavior
When a DNAT rule is configured via iptables with different port ranges,
iptables -t nat -A PREROUTING -p tcp -d 10.0.0.2 -m tcp --dport 32000:32010
-j DNAT --to-destination 192.168.0.10:21000-21010
we seem to be DNATing to some random port on the LAN side. While this is
expected if --random is passed to the iptables command, it is not
expected without passing --random. The expected behavior (and the
observed behavior prior to the commit in the "Fixes" tag) is the traffic
will be DNAT'd to 192.168.0.10:21000 unless there is a tuple collision
with that destination. In that case, we expect the traffic to be
instead DNAT'd to 192.168.0.10:21001, so on so forth until the end of
the range.
This patch intends to restore the behavior observed prior to the "Fixes"
tag.
Fixes: 6ed5943f8735 ("netfilter: nat: remove l4 protocol port rovers")
Signed-off-by: Kyle Swenson <kyle.swenson@est.tech>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Diffstat (limited to 'net')
| -rw-r--r-- | net/netfilter/nf_nat_core.c | 5 |
1 files changed, 4 insertions, 1 deletions
diff --git a/net/netfilter/nf_nat_core.c b/net/netfilter/nf_nat_core.c index c3d7ecbc777c..016c816d91cb 100644 --- a/net/netfilter/nf_nat_core.c +++ b/net/netfilter/nf_nat_core.c @@ -551,8 +551,11 @@ static void nf_nat_l4proto_unique_tuple(struct nf_conntrack_tuple *tuple, find_free_id: if (range->flags & NF_NAT_RANGE_PROTO_OFFSET) off = (ntohs(*keyptr) - ntohs(range->base_proto.all)); - else + else if ((range->flags & NF_NAT_RANGE_PROTO_RANDOM_ALL) || + maniptype != NF_NAT_MANIP_DST) off = get_random_u16(); + else + off = 0; attempts = range_size; if (attempts > NF_NAT_MAX_ATTEMPTS) |