[PATCH 4.20 34/80] ipv6: Consider sk_bound_dev_if when binding a socket to an address

[Greg Kroah-Hartman]

4.20-stable review patch.  If anyone has any objections, please let me know.

------------------

From: David Ahern <dsah...@gmail.com>

[ Upstream commit c5ee066333ebc322a24a00a743ed941a0c68617e ]

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 <dsah...@gmail.com>
Signed-off-by: David S. Miller <da...@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>
---
 net/ipv6/af_inet6.c |    3 +++
 1 file changed, 3 insertions(+)

--- a/net/ipv6/af_inet6.c
+++ b/net/ipv6/af_inet6.c
@@ -362,6 +362,9 @@ static int __inet6_bind(struct sock *sk,
                                        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;