l2tp: consider '::' as wildcard address in l2tp_ip6 socket lookup

[ Upstream commit 97b84fd6d91766ea57dcc350d78f42639e011c30 ]

An L2TP socket bound to the unspecified address should match with any
address. If not, it can't receive any packet and __l2tp_ip6_bind_lookup()
can't prevent another socket from binding on the same device/tunnel ID.

While there, rename the 'addr' variable to 'sk_laddr' (local addr), to
make following patch clearer.

Signed-off-by: Guillaume Nault <g.nault@alphalink.fr>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/net/l2tp/l2tp_ip6.c b/net/l2tp/l2tp_ip6.c
index b10abef..1d522ce 100644 (file)
--- a/net/l2tp/l2tp_ip6.c
+++ b/net/l2tp/l2tp_ip6.c
@@ -64,7 +64,7 @@ static struct sock *__l2tp_ip6_bind_lookup(struct net *net,
        struct sock *sk;
 
        sk_for_each_bound(sk, &l2tp_ip6_bind_table) {
-               const struct in6_addr *addr = inet6_rcv_saddr(sk);
+               const struct in6_addr *sk_laddr = inet6_rcv_saddr(sk);
                struct l2tp_ip6_sock *l2tp = l2tp_ip6_sk(sk);
 
                if (l2tp == NULL)
@@ -72,7 +72,7 @@ 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_laddr || ipv6_addr_any(sk_laddr) || ipv6_addr_equal(sk_laddr, laddr)) &&
                    (!sk->sk_bound_dev_if || !dif ||
                     sk->sk_bound_dev_if == dif))
                        goto found;