d8a7b7a3cd
kernel access control. Provide implementations of some sample operating system security policy extensions. These are not yet hooked up to the build as other infrastructure is still being committed. Most of these work fairly well and are in daily use in our development and (limited) production environments. Some are not yet in their final form, and a number of the labeled policies waste a lot of kernel memory and will be fixed over the next month or so to be more conservative. They do give good examples of the flexibility of the MAC framework for implementing a variety of security policies. mac_biba: Implementation of fixed-label Biba integrity policy, similar to those found in a number of commercial trusted operating systems. All subjects and objects are assigned integrity levels, and information flow is controlled based on a read-up, write-down policy. Currently, purely hierarchal. mac_bsdextended: Implementation of a "file system firewall", which allows the administrator to specify a series of rules limiting access by users and groups to objects owned by other users and groups. This policy is unlabeled, relying on existing system security labeling (file permissions/ownership, process credentials). mac_ifoff: Secure interface silencing. Special-purpose module to limit inappropriate out-going network traffic for silent monitoring scenarios. Prevents the various network stacks from generating any output despite an interface being live for reception. mac_mls: Implementation of fixed-label Multi-Level Security confidentiality policy, similar to those found in a number of commercial trusted operating systems. All subjects and objects are assigned confidentiality levels, and information flow is controlled based on a write-up, read-down policy. Currently, purely hiearchal, although non-hierarchal support is in the works. mac_none: Policy module implementing all MAC policy entry points with empty stubs. A good place to start if you want all the prototypes types in for you, and don't mind a bit of pruning. Can be loaded, but has no access control impact. Useful also for performance measurements. mac_seeotheruids: Policy module implementing a security service similar to security.bsd.seeotheruids, only a slightly more detailed policy involving exceptions for members of specific groups, etc. This policy is unlabeled, relying on existing system security labeling (process credentials). mac_test: Policy module implementing basic sanity tests for label handling. Attempts to ensure that labels are not freed multiple times, etc, etc. Obtained from: TrustedBSD Project Sponsored by: DARPA, NAI Labs
174 lines
5.3 KiB
C
174 lines
5.3 KiB
C
/*-
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* Copyright (c) 1999, 2000, 2001, 2002 Robert N. M. Watson
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* Copyright (c) 2001, 2002 Networks Associates Technology, Inc.
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* All rights reserved.
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*
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* This software was developed by Robert Watson for the TrustedBSD Project.
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*
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* This software was developed for the FreeBSD Project in part by NAI Labs,
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* the Security Research Division of Network Associates, Inc. under
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* DARPA/SPAWAR contract N66001-01-C-8035 ("CBOSS"), as part of the DARPA
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* CHATS research program.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. The names of the authors may not be used to endorse or promote
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* products derived from this software without specific prior written
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* permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* $FreeBSD$
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*/
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/*
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* Developed by the TrustedBSD Project.
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* Limit access to interfaces until they are specifically administratively
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* enabled. Prevents protocol stack-driven packet leakage in unsafe
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* environments.
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*/
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#include <sys/types.h>
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#include <sys/param.h>
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#include <sys/conf.h>
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#include <sys/kernel.h>
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#include <sys/mac.h>
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#include <sys/mount.h>
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#include <sys/proc.h>
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#include <sys/systm.h>
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#include <sys/sysproto.h>
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#include <sys/sysent.h>
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#include <sys/vnode.h>
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#include <sys/file.h>
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#include <sys/socket.h>
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#include <sys/socketvar.h>
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#include <sys/sysctl.h>
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#include <net/bpfdesc.h>
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#include <net/if.h>
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#include <net/if_types.h>
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#include <net/if_var.h>
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#include <vm/vm.h>
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#include <sys/mac_policy.h>
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SYSCTL_DECL(_security_mac);
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SYSCTL_NODE(_security_mac, OID_AUTO, ifoff, CTLFLAG_RW, 0,
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"TrustedBSD mac_ifoff policy controls");
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static int mac_ifoff_enabled = 1;
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SYSCTL_INT(_security_mac_ifoff, OID_AUTO, enabled, CTLFLAG_RW,
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&mac_ifoff_enabled, 0, "Enforce ifoff policy");
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TUNABLE_INT("security.mac.ifoff.enabled", &mac_ifoff_enabled);
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static int mac_ifoff_lo_enabled = 1;
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SYSCTL_INT(_security_mac_ifoff, OID_AUTO, lo_enabled, CTLFLAG_RW,
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&mac_ifoff_lo_enabled, 0, "Enable loopback interfaces");
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TUNABLE_INT("security.mac.ifoff.lo_enabled", &mac_ifoff_lo_enabled);
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static int mac_ifoff_other_enabled = 0;
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SYSCTL_INT(_security_mac_ifoff, OID_AUTO, other_enabled, CTLFLAG_RW,
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&mac_ifoff_other_enabled, 0, "Enable other interfaces");
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TUNABLE_INT("security.mac.ifoff.other_enabled", &mac_ifoff_other_enabled);
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static int mac_ifoff_bpfrecv_enabled = 0;
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SYSCTL_INT(_security_mac_ifoff, OID_AUTO, bpfrecv_enabled, CTLFLAG_RW,
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&mac_ifoff_bpfrecv_enabled, 0, "Enable BPF reception even when interface "
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"is disabled");
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TUNABLE_INT("security.mac.ifoff.bpfrecv.enabled", &mac_ifoff_bpfrecv_enabled);
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static int
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check_ifnet_outgoing(struct ifnet *ifnet)
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{
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if (!mac_ifoff_enabled)
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return (0);
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if (mac_ifoff_lo_enabled && ifnet->if_type == IFT_LOOP)
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return (0);
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if (mac_ifoff_other_enabled && ifnet->if_type != IFT_LOOP)
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return (0);
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return (EPERM);
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}
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static int
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check_ifnet_incoming(struct ifnet *ifnet, int viabpf)
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{
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if (!mac_ifoff_enabled)
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return (0);
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if (mac_ifoff_lo_enabled && ifnet->if_type == IFT_LOOP)
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return (0);
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if (mac_ifoff_other_enabled && ifnet->if_type != IFT_LOOP)
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return (0);
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if (viabpf && mac_ifoff_bpfrecv_enabled)
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return (0);
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return (EPERM);
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}
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static int
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mac_ifoff_check_bpfdesc_receive(struct bpf_d *bpf_d, struct label *bpflabel,
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struct ifnet *ifnet, struct label *ifnetlabel)
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{
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return (check_ifnet_incoming(ifnet, 1));
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}
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static int
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mac_ifoff_check_ifnet_transmit(struct ifnet *ifnet, struct label *ifnetlabel,
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struct mbuf *m, struct label *mbuflabel)
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{
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return (check_ifnet_outgoing(ifnet));
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}
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static int
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mac_ifoff_check_socket_receive(struct socket *so, struct label *socketlabel,
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struct mbuf *m, struct label *mbuflabel)
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{
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if (m->m_flags & M_PKTHDR) {
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if (m->m_pkthdr.rcvif != NULL)
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return (check_ifnet_incoming(m->m_pkthdr.rcvif, 0));
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}
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return (0);
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}
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static struct mac_policy_op_entry mac_ifoff_ops[] =
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{
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{ MAC_CHECK_BPFDESC_RECEIVE,
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(macop_t)mac_ifoff_check_bpfdesc_receive },
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{ MAC_CHECK_IFNET_TRANSMIT,
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(macop_t)mac_ifoff_check_ifnet_transmit },
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{ MAC_CHECK_SOCKET_RECEIVE,
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(macop_t)mac_ifoff_check_socket_receive },
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{ MAC_OP_LAST, NULL }
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};
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MAC_POLICY_SET(mac_ifoff_ops, trustedbsd_mac_ifoff, "TrustedBSD MAC/ifoff",
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MPC_LOADTIME_FLAG_UNLOADOK, NULL);
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