From: Stephen Hemminger Date: Tue, 19 Aug 2008 04:32:32 +0000 (-0700) Subject: nf_nat: use secure_ipv4_port_ephemeral() for NAT port randomization X-Git-Tag: v2.6.27-rc4~39^2~5 X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=9f593653742d1dd816c4e94c6e5154a57ccba6d1;p=linux-2.6 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 [ added missing EXPORT_SYMBOL_GPL ] Signed-off-by: Patrick McHardy Signed-off-by: David S. Miller --- diff --git a/drivers/char/random.c b/drivers/char/random.c index e0d0e37190..1838aa3d24 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 91537f1127..6c4f11f514 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);