nf_nat: use secure_ipv4_port_ephemeral() for NAT port randomization
Use incoming network tuple as seed for NAT port randomization.
This avoids concerns of leaking net_random() bits, and also gives better
port distribution. Don't have NAT server, compile tested only.
Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>
[ added missing EXPORT_SYMBOL_GPL ]
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv4/netfilter/nf_nat_proto_common.c b/net/ipv4/netfilter/nf_nat_proto_common.c
index 91537f1..6c4f11f 100644
--- a/net/ipv4/netfilter/nf_nat_proto_common.c
+++ b/net/ipv4/netfilter/nf_nat_proto_common.c
@@ -73,9 +73,13 @@
range_size = ntohs(range->max.all) - min + 1;
}
- off = *rover;
if (range->flags & IP_NAT_RANGE_PROTO_RANDOM)
- off = net_random();
+ off = secure_ipv4_port_ephemeral(tuple->src.u3.ip, tuple->dst.u3.ip,
+ maniptype == IP_NAT_MANIP_SRC
+ ? tuple->dst.u.all
+ : tuple->src.u.all);
+ else
+ off = *rover;
for (i = 0; i < range_size; i++, off++) {
*portptr = htons(min + off % range_size);