[PATCH] NET: Ensure device name passed to SO_BINDTODEVICE is NULL terminated.

The user can pass us arbitrary garbage so we should ensure the
string they give us is null terminated before we pass it on
to dev_get_by_index() et al.

Found by Solar Designer.

Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Chris Wright <chrisw@sous-sol.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>