From: David Ahern <dsahern@gmail.com>
Date: Wed, 2 Jan 2019 18:57:09 -0800
Subject: ipv6: Consider sk_bound_dev_if when binding a socket to an address
Git-commit: c5ee066333ebc322a24a00a743ed941a0c68617e
Patch-mainline: v5.0-rc1
References: networking-stable-19_02_01

IPv6 does not consider if the socket is bound to a device when binding
to an address. The result is that a socket can be bound to eth0 and then
bound to the address of eth1. If the device is a VRF, the result is that
a socket can only be bound to an address in the default VRF.

Resolve by considering the device if sk_bound_dev_if is set.

This problem 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: Jiri Slaby <jslaby@suse.cz>
---
 net/ipv6/af_inet6.c |    3 +++
 1 file changed, 3 insertions(+)

--- a/net/ipv6/af_inet6.c
+++ b/net/ipv6/af_inet6.c
@@ -357,6 +357,9 @@ int inet6_bind(struct socket *sock, stru
 					err = -EINVAL;
 					goto out_unlock;
 				}
+			}
+
+			if (sk->sk_bound_dev_if) {
 				dev = dev_get_by_index_rcu(net, sk->sk_bound_dev_if);
 				if (!dev) {
 					err = -ENODEV;