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authorGuillaume Nault <g.nault@alphalink.fr>2016-11-29 15:09:47 +0300
committerDavid S. Miller <davem@davemloft.net>2016-11-30 22:14:08 +0300
commitdf90e6886146dd744eb3929782e6df9749cd4a69 (patch)
treeb9e1e821b3f0b3572724ba9e4817f36d8c23a420 /net/l2tp/l2tp_ip.c
parentd5e3a190937a1e386671266202c62565741f0f1a (diff)
downloadlinux-df90e6886146dd744eb3929782e6df9749cd4a69.tar.xz
l2tp: fix lookup for sockets not bound to a device in l2tp_ip
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>
Diffstat (limited to 'net/l2tp/l2tp_ip.c')
-rw-r--r--net/l2tp/l2tp_ip.c6
1 files changed, 4 insertions, 2 deletions
diff --git a/net/l2tp/l2tp_ip.c b/net/l2tp/l2tp_ip.c
index b517c3366922..8938b6ba57a0 100644
--- a/net/l2tp/l2tp_ip.c
+++ b/net/l2tp/l2tp_ip.c
@@ -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;