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@xxxxxxxxxx>
[ added missing EXPORT_SYMBOL_GPL ]
Signed-off-by: Patrick McHardy <kaber@xxxxxxxxx>
---
commit 288787c6d3d50245d718537142800762d7ff1181
tree da622065f39a1adeb8323ab2549f8638adaffbd6
parent be6e3721aa813e40f20d84d7925f9cf5cd8eef2d
author Stephen Hemminger <shemminger@xxxxxxxxxx> Mon, 18 Aug 2008 18:35:09 +0200
committer Patrick McHardy <kaber@xxxxxxxxx> Mon, 18 Aug 2008 18:35:09 +0200
drivers/char/random.c | 1 +
net/ipv4/netfilter/nf_nat_proto_common.c | 8 ++++++--
2 files changed, 7 insertions(+), 2 deletions(-)
diff --git a/drivers/char/random.c b/drivers/char/random.c
index e0d0e37..1838aa3 100644
--- a/drivers/char/random.c
+++ b/drivers/char/random.c
@@ -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,
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 @@ 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);
--
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