text: /*-
   * Copyright (c) 1999, 2000, 2001, 2002 Robert N. M. Watson
   * Copyright (c) 2001, 2002 Networks Associates Technology, Inc.
   * All rights reserved.
   *
   * This software was developed by Robert Watson for the TrustedBSD Project.
   *
   * This software was developed for the FreeBSD Project in part by Network
   * Associates Laboratories, the Security Research Division of Network
   * Associates, Inc. under DARPA/SPAWAR contract N66001-01-C-8035 ("CBOSS"),
   * as part of the DARPA CHATS research program.
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions
   * are met:
   * 1. Redistributions of source code must retain the above copyright
   *    notice, this list of conditions and the following disclaimer.
   * 2. Redistributions in binary form must reproduce the above copyright
   *    notice, this list of conditions and the following disclaimer in the
   *    documentation and/or other materials provided with the distribution.
   *
   * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
   * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
   * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   * SUCH DAMAGE.
   *
   * $FreeBSD: src/sys/security/mac_ifoff/mac_ifoff.c,v 1.8 2003/11/18 00:39:06 rwatson Exp $
   */
  
  /*
   * Developed by the TrustedBSD Project.
   * Limit access to interfaces until they are specifically administratively
   * enabled.  Prevents protocol stack-driven packet leakage in unsafe
   * environments.
   */
  
  #include <sys/types.h>
  #include <sys/param.h>
  #include <sys/conf.h>
  #include <sys/kernel.h>
  #include <sys/mac.h>
  #include <sys/mount.h>
  #include <sys/proc.h>
  #include <sys/systm.h>
  #include <sys/sysproto.h>
  #include <sys/sysent.h>
  #include <sys/vnode.h>
  #include <sys/file.h>
  #include <sys/socket.h>
  #include <sys/socketvar.h>
  #include <sys/sysctl.h>
  
  #include <net/bpfdesc.h>
  #include <net/if.h>
  #include <net/if_types.h>
  #include <net/if_var.h>
  
  #include <vm/vm.h>
  
  #include <sys/mac_policy.h>
  
  SYSCTL_DECL(_security_mac);
  
  SYSCTL_NODE(_security_mac, OID_AUTO, ifoff, CTLFLAG_RW, 0,
      "TrustedBSD mac_ifoff policy controls");
  
  static int	mac_ifoff_enabled = 1;
  SYSCTL_INT(_security_mac_ifoff, OID_AUTO, enabled, CTLFLAG_RW,
      &mac_ifoff_enabled, 0, "Enforce ifoff policy");
  TUNABLE_INT("security.mac.ifoff.enabled", &mac_ifoff_enabled);
  
  static int	mac_ifoff_lo_enabled = 1;
  SYSCTL_INT(_security_mac_ifoff, OID_AUTO, lo_enabled, CTLFLAG_RW,
      &mac_ifoff_lo_enabled, 0, "Enable loopback interfaces");
  TUNABLE_INT("security.mac.ifoff.lo_enabled", &mac_ifoff_lo_enabled);
  
  static int	mac_ifoff_other_enabled = 0;
  SYSCTL_INT(_security_mac_ifoff, OID_AUTO, other_enabled, CTLFLAG_RW,
      &mac_ifoff_other_enabled, 0, "Enable other interfaces");
  TUNABLE_INT("security.mac.ifoff.other_enabled", &mac_ifoff_other_enabled);
  
  static int	mac_ifoff_bpfrecv_enabled = 0;
  SYSCTL_INT(_security_mac_ifoff, OID_AUTO, bpfrecv_enabled, CTLFLAG_RW,
      &mac_ifoff_bpfrecv_enabled, 0, "Enable BPF reception even when interface "
      "is disabled");
  TUNABLE_INT("security.mac.ifoff.bpfrecv.enabled", &mac_ifoff_bpfrecv_enabled);
  
  static int
  check_ifnet_outgoing(struct ifnet *ifnet)
  {
  
  	if (!mac_ifoff_enabled)
  		return (0);
  
  	if (mac_ifoff_lo_enabled && ifnet->if_type == IFT_LOOP)
  		return (0);
  
  	if (mac_ifoff_other_enabled && ifnet->if_type != IFT_LOOP)
  		return (0);
  
  	return (EPERM);
  }
  
  static int
  check_ifnet_incoming(struct ifnet *ifnet, int viabpf)
  {
  	if (!mac_ifoff_enabled)
  		return (0);
  
  	if (mac_ifoff_lo_enabled && ifnet->if_type == IFT_LOOP)
  		return (0);
  
  	if (mac_ifoff_other_enabled && ifnet->if_type != IFT_LOOP)
  		return (0);
  
  	if (viabpf && mac_ifoff_bpfrecv_enabled)
  		return (0);
  
  	return (EPERM);
  }
  
  static int
  mac_ifoff_check_bpfdesc_receive(struct bpf_d *bpf_d, struct label *bpflabel,
      struct ifnet *ifnet, struct label *ifnetlabel)
  {
  
  	return (check_ifnet_incoming(ifnet, 1));
  }
  
  static int
  mac_ifoff_check_ifnet_transmit(struct ifnet *ifnet, struct label *ifnetlabel,
      struct mbuf *m, struct label *mbuflabel)
  {
  
  	return (check_ifnet_outgoing(ifnet));
  }
  
  static int
  mac_ifoff_check_inpcb_deliver(struct inpcb *inp, struct label *inplabel,
      struct mbuf *m, struct label *mlabel)
  {
  
  	M_ASSERTPKTHDR(m);
  	if (m->m_pkthdr.rcvif != NULL)
  		return (check_ifnet_incoming(m->m_pkthdr.rcvif, 0));
  
  	return (0);
  }
  
  static int
  mac_ifoff_check_socket_deliver(struct socket *so, struct label *socketlabel,
      struct mbuf *m, struct label *mbuflabel)
  {
  
  	M_ASSERTPKTHDR(m);
  	if (m->m_pkthdr.rcvif != NULL)
  		return (check_ifnet_incoming(m->m_pkthdr.rcvif, 0));
  
  	return (0);
  }
  
  static struct mac_policy_ops mac_ifoff_ops =
  {
  	.mpo_check_bpfdesc_receive = mac_ifoff_check_bpfdesc_receive,
  	.mpo_check_ifnet_transmit = mac_ifoff_check_ifnet_transmit,
  	.mpo_check_inpcb_deliver = mac_ifoff_check_inpcb_deliver,
  	.mpo_check_socket_deliver = mac_ifoff_check_socket_deliver,
  };
  
  MAC_POLICY_SET(&mac_ifoff_ops, mac_ifoff, "TrustedBSD MAC/ifoff",
      MPC_LOADTIME_FLAG_UNLOADOK, NULL);
  