l2tp: fix lookup for sockets not bound to a device in l2tp_ip (df90e688) · Commits · 戴 / test

When looking up an l2tp socket, we must consider a null netdevice id as wild card. There are currently two problems caused by __l2tp_ip_bind_lookup() not considering 'dif' as wild card when set to 0: * A socket bound to a device (i.e. with sk->sk_bound_dev_if != 0) never receives any packet. Since __l2tp_ip_bind_lookup() is called with dif == 0 in l2tp_ip_recv(), sk->sk_bound_dev_if is always different from 'dif' so the socket doesn't match. * Two sockets, one bound to a device but not the other, can be bound to the same address. If the first socket binding to the address is the one that is also bound to a device, the second socket can bind to the same address without __l2tp_ip_bind_lookup() noticing the overlap. To fix this issue, we need to consider that any null device index, be it 'sk->sk_bound_dev_if' or 'dif', matches with any other value. We also need to pass the input device index to __l2tp_ip_bind_lookup() on reception so that sockets bound to a device never receive packets from other devices. This patch fixes l2tp_ip6 in the same way. Signed-off-by:

Guillaume Nault <g.nault@alphalink.fr> Signed-off-by:

David S. Miller <davem@davemloft.net>

net/l2tp/l2tp_ip.c

+4 −2

Original line number	Diff line number	Diff line
		@@ -61,7 +61,8 @@ static struct sock __l2tp_ip_bind_lookup(struct net net, __be32 laddr, int dif
		if ((l2tp->conn_id == tunnel_id) &&
		net_eq(sock_net(sk), net) &&
		!(inet->inet_rcv_saddr && inet->inet_rcv_saddr != laddr) &&
		!(sk->sk_bound_dev_if && sk->sk_bound_dev_if != dif))
		(!sk->sk_bound_dev_if \|\| !dif \|\|
		sk->sk_bound_dev_if == dif))
		goto found;
		}

		@@ -182,7 +183,8 @@ pass_up:
		struct iphdr iph = (struct iphdr ) skb_network_header(skb);

		read_lock_bh(&l2tp_ip_lock);
		sk = __l2tp_ip_bind_lookup(net, iph->daddr, 0, tunnel_id);
		sk = __l2tp_ip_bind_lookup(net, iph->daddr, inet_iif(skb),
		tunnel_id);
		if (!sk) {
		read_unlock_bh(&l2tp_ip_lock);
		goto discard;

net/l2tp/l2tp_ip6.c

+4 −3

Original line number	Diff line number	Diff line
		@@ -73,7 +73,8 @@ static struct sock __l2tp_ip6_bind_lookup(struct net net,
		if ((l2tp->conn_id == tunnel_id) &&
		net_eq(sock_net(sk), net) &&
		!(addr && ipv6_addr_equal(addr, laddr)) &&
		!(sk->sk_bound_dev_if && sk->sk_bound_dev_if != dif))
		(!sk->sk_bound_dev_if \|\| !dif \|\|
		sk->sk_bound_dev_if == dif))
		goto found;
		}

		@@ -196,8 +197,8 @@ pass_up:
		struct ipv6hdr *iph = ipv6_hdr(skb);

		read_lock_bh(&l2tp_ip6_lock);
		sk = __l2tp_ip6_bind_lookup(net, &iph->daddr,
		0, tunnel_id);
		sk = __l2tp_ip6_bind_lookup(net, &iph->daddr, inet6_iif(skb),
		tunnel_id);
		if (!sk) {
		read_unlock_bh(&l2tp_ip6_lock);
		goto discard;

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