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Commit 9f593653 authored by Stephen Hemminger's avatar Stephen Hemminger Committed by David S. Miller
Browse files

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: default avatarStephen Hemminger <shemminger@vyatta.com>

[ added missing EXPORT_SYMBOL_GPL ]

Signed-off-by: default avatarPatrick McHardy <kaber@trash.net>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent fab00c5d

drivers/char/random.c

+1 −0
Original line number Diff line number Diff line
@@ -1571,6 +1571,7 @@ u32 secure_ipv4_port_ephemeral(__be32 saddr, __be32 daddr, __be16 dport) 


	return half_md4_transform(hash, keyptr->secret);

}

EXPORT_SYMBOL_GPL(secure_ipv4_port_ephemeral);



#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)

u32 secure_ipv6_port_ephemeral(const __be32 *saddr, const __be32 *daddr,

net/ipv4/netfilter/nf_nat_proto_common.c

+6 −2
Original line number Diff line number Diff line
@@ -73,9 +73,13 @@ bool nf_nat_proto_unique_tuple(struct nf_conntrack_tuple *tuple, 
		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);