ipv6: Consider sk_bound_dev_if when binding a socket to a v4 mapped address

BugLink: https://bugs.launchpad.net/bugs/1818797

[ Upstream commit ec90ad33 ]

Similar to c5ee0663 ("ipv6: Consider sk_bound_dev_if when binding a
socket to an address"), binding a socket to v4 mapped addresses needs to
consider if the socket is bound to a device.

This problem also exists from the beginning of git history.
Signed-off-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Juerg Haefliger <juergh@canonical.com>
Signed-off-by: Khalid Elmously <khalid.elmously@canonical.com>

net/ipv6/af_inet6.c

@@ -292,6 +292,7 @@ int inet6_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len)
 
 	/* Check if the address belongs to the host. */
 	if (addr_type == IPV6_ADDR_MAPPED) {
+		struct net_device *dev = NULL;
 		int chk_addr_ret;
 
 		/* Binding to v4-mapped address on a v6-only socket
@@ -302,9 +303,17 @@ int inet6_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len)
 			goto out;
 		}
 
+		if (sk->sk_bound_dev_if) {
+			dev = dev_get_by_index_rcu(net, sk->sk_bound_dev_if);
+			if (!dev) {
+				err = -ENODEV;
+				goto out;
+			}
+		}
+
 		/* Reproduce AF_INET checks to make the bindings consistent */
 		v4addr = addr->sin6_addr.s6_addr32[3];
-		chk_addr_ret = inet_addr_type(net, v4addr);
+		chk_addr_ret = inet_addr_type_dev_table(net, dev, v4addr);
 		if (!net->ipv4.sysctl_ip_nonlocal_bind &&
 		    !(inet->freebind || inet->transparent) &&
 		    v4addr != htonl(INADDR_ANY) &&