FreeBSD/Linux Kernel Cross Reference
sys/security/mac_ifoff/mac_ifoff.c

     /*-
      * Copyright (c) 1999-2002, 2007 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.
     *
     * $FreeBSD$
     */
    
    /*
     * 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/param.h>
    #include <sys/kernel.h>
    #include <sys/module.h>
    #include <sys/socket.h>
    #include <sys/sysctl.h>
    
    #include <net/bpfdesc.h>
    #include <net/if_types.h>
    
    #include <security/mac/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 *ifp)
    {
    
            if (!mac_ifoff_enabled)
                    return (0);
    
            if (mac_ifoff_lo_enabled && ifp->if_type == IFT_LOOP)
                    return (0);
    
            if (mac_ifoff_other_enabled && ifp->if_type != IFT_LOOP)
                    return (0);
    
            return (EPERM);
    }
    
    static int
    check_ifnet_incoming(struct ifnet *ifp, int viabpf)
    {
           if (!mac_ifoff_enabled)
                   return (0);
   
           if (mac_ifoff_lo_enabled && ifp->if_type == IFT_LOOP)
                   return (0);
   
           if (mac_ifoff_other_enabled && ifp->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 *d, struct label *dlabel,
       struct ifnet *ifp, struct label *ifplabel)
   {
   
           return (check_ifnet_incoming(ifp, 1));
   }
   
   static int
   mac_ifoff_check_ifnet_transmit(struct ifnet *ifp, struct label *ifplabel,
       struct mbuf *m, struct label *mlabel)
   {
   
           return (check_ifnet_outgoing(ifp));
   }
   
   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 *solabel,
       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 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);

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