net: Fix ns_capable check in sock_diag_put_filterinfo

The caller needs capabilities on the namespace being queried, not on
their own namespace.  This is a security bug, although it likely has
only a minor impact.

Cc: stable@vger.kernel.org
Signed-off-by: Andy Lutomirski <luto@amacapital.net>
Acked-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --cc include/linux/sock_diag.h
Simple merge

diff --cc net/core/sock_diag.c
Simple merge

diff --cc net/packet/diag.c
Simple merge