freebsd-skq/sys/security/mac_ifoff/mac_ifoff.c
rwatson 5743072acf Rather than having MAC policies explicitly declare what object types
they label, derive that information implicitly from the set of label
initializers in their policy operations set.  This avoids a possible
class of programmer errors, while retaining the structure that
allows us to avoid allocating labels for objects that don't need
them.  As before, we regenerate a global mask of labeled objects
each time a policy is loaded or unloaded, stored in mac_labeled.

Discussed with:   csjp
Suggested by:     Jacques Vidrine <nectar at apple.com>
Obtained from:    TrustedBSD Project
Sponsored by:     Apple, Inc.
2009-01-10 10:58:41 +00:00

174 lines
5.2 KiB
C

/*-
* Copyright (c) 1999-2002, 2007 Robert N. M. Watson
* Copyright (c) 2001-2002 Networks Associates Technology, Inc.
* Copyright (c) 2006 SPARTA, 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.
*
* This software was enhanced by SPARTA ISSO under SPAWAR contract
* N66001-04-C-6019 ("SEFOS").
*
* 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 ifoff_enabled = 1;
SYSCTL_INT(_security_mac_ifoff, OID_AUTO, enabled, CTLFLAG_RW,
&ifoff_enabled, 0, "Enforce ifoff policy");
TUNABLE_INT("security.mac.ifoff.enabled", &ifoff_enabled);
static int ifoff_lo_enabled = 1;
SYSCTL_INT(_security_mac_ifoff, OID_AUTO, lo_enabled, CTLFLAG_RW,
&ifoff_lo_enabled, 0, "Enable loopback interfaces");
TUNABLE_INT("security.mac.ifoff.lo_enabled", &ifoff_lo_enabled);
static int ifoff_other_enabled = 0;
SYSCTL_INT(_security_mac_ifoff, OID_AUTO, other_enabled, CTLFLAG_RW,
&ifoff_other_enabled, 0, "Enable other interfaces");
TUNABLE_INT("security.mac.ifoff.other_enabled", &ifoff_other_enabled);
static int ifoff_bpfrecv_enabled = 0;
SYSCTL_INT(_security_mac_ifoff, OID_AUTO, bpfrecv_enabled, CTLFLAG_RW,
&ifoff_bpfrecv_enabled, 0, "Enable BPF reception even when interface "
"is disabled");
TUNABLE_INT("security.mac.ifoff.bpfrecv.enabled", &ifoff_bpfrecv_enabled);
static int
ifnet_check_outgoing(struct ifnet *ifp)
{
if (!ifoff_enabled)
return (0);
if (ifoff_lo_enabled && ifp->if_type == IFT_LOOP)
return (0);
if (ifoff_other_enabled && ifp->if_type != IFT_LOOP)
return (0);
return (EPERM);
}
static int
ifnet_check_incoming(struct ifnet *ifp, int viabpf)
{
if (!ifoff_enabled)
return (0);
if (ifoff_lo_enabled && ifp->if_type == IFT_LOOP)
return (0);
if (ifoff_other_enabled && ifp->if_type != IFT_LOOP)
return (0);
if (viabpf && ifoff_bpfrecv_enabled)
return (0);
return (EPERM);
}
/*
* Object-specific entry point implementations are sorted alphabetically by
* object type and then by operation.
*/
static int
ifoff_bpfdesc_check_receive(struct bpf_d *d, struct label *dlabel,
struct ifnet *ifp, struct label *ifplabel)
{
return (ifnet_check_incoming(ifp, 1));
}
static int
ifoff_ifnet_check_transmit(struct ifnet *ifp, struct label *ifplabel,
struct mbuf *m, struct label *mlabel)
{
return (ifnet_check_outgoing(ifp));
}
static int
ifoff_inpcb_check_deliver(struct inpcb *inp, struct label *inplabel,
struct mbuf *m, struct label *mlabel)
{
M_ASSERTPKTHDR(m);
if (m->m_pkthdr.rcvif != NULL)
return (ifnet_check_incoming(m->m_pkthdr.rcvif, 0));
return (0);
}
static int
ifoff_socket_check_deliver(struct socket *so, struct label *solabel,
struct mbuf *m, struct label *mlabel)
{
M_ASSERTPKTHDR(m);
if (m->m_pkthdr.rcvif != NULL)
return (ifnet_check_incoming(m->m_pkthdr.rcvif, 0));
return (0);
}
static struct mac_policy_ops ifoff_ops =
{
.mpo_bpfdesc_check_receive = ifoff_bpfdesc_check_receive,
.mpo_ifnet_check_transmit = ifoff_ifnet_check_transmit,
.mpo_inpcb_check_deliver = ifoff_inpcb_check_deliver,
.mpo_socket_check_deliver = ifoff_socket_check_deliver,
};
MAC_POLICY_SET(&ifoff_ops, mac_ifoff, "TrustedBSD MAC/ifoff",
MPC_LOADTIME_FLAG_UNLOADOK, NULL);