From 7a02bf892d8f1e5298af1676f001bee410509d80 Mon Sep 17 00:00:00 2001 From: Johannes Berg Date: Thu, 4 Feb 2016 13:31:20 +0100 Subject: ipv6: add option to drop unsolicited neighbor advertisements In certain 802.11 wireless deployments, there will be NA proxies that use knowledge of the network to correctly answer requests. To prevent unsolicitd advertisements on the shared medium from being a problem, on such deployments wireless needs to drop them. Enable this by providing an option called "drop_unsolicited_na". Signed-off-by: Johannes Berg Signed-off-by: David S. Miller --- net/ipv6/ndisc.c | 9 +++++++++ 1 file changed, 9 insertions(+) (limited to 'net/ipv6/ndisc.c') diff --git a/net/ipv6/ndisc.c b/net/ipv6/ndisc.c index 84afb9a77278..c245895a3d41 100644 --- a/net/ipv6/ndisc.c +++ b/net/ipv6/ndisc.c @@ -883,6 +883,7 @@ static void ndisc_recv_na(struct sk_buff *skb) offsetof(struct nd_msg, opt)); struct ndisc_options ndopts; struct net_device *dev = skb->dev; + struct inet6_dev *idev = __in6_dev_get(dev); struct inet6_ifaddr *ifp; struct neighbour *neigh; @@ -902,6 +903,14 @@ static void ndisc_recv_na(struct sk_buff *skb) return; } + /* For some 802.11 wireless deployments (and possibly other networks), + * there will be a NA proxy and unsolicitd packets are attacks + * and thus should not be accepted. + */ + if (!msg->icmph.icmp6_solicited && idev && + idev->cnf.drop_unsolicited_na) + return; + if (!ndisc_parse_options(msg->opt, ndoptlen, &ndopts)) { ND_PRINTK(2, warn, "NS: invalid ND option\n"); return; -- cgit v1.2.3-58-ga151