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nf_nat: use secure_ipv4_port_ephemeral() for NAT port randomization

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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>
This commit is contained in:
Stephen Hemminger 2008-08-18 21:32:32 -07:00 committed by David S. Miller
parent fab00c5d15
commit 9f59365374
2 changed files with 7 additions and 2 deletions
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1
drivers/char/random.c
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@ -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,

8
net/ipv4/netfilter/nf_nat_proto_common.c
View File

@ -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);