xref: /freebsd-11-stable/sys/security/mac_biba/mac_biba.c

/*-
 * Copyright (c) 1999-2002, 2007 Robert N. M. Watson
 * Copyright (c) 2001-2005 McAfee, 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 McAfee
 * Research, the Security Research Division of McAfee, 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: head/sys/security/mac_biba/mac_biba.c 166617 2007-02-10 08:59:39Z rwatson $
 */

/*
 * Developed by the TrustedBSD Project.
 * Biba fixed label mandatory integrity policy.
 */

#include <sys/types.h>
#include <sys/param.h>
#include <sys/acl.h>
#include <sys/conf.h>
#include <sys/extattr.h>
#include <sys/kernel.h>
#include <sys/ksem.h>
#include <sys/malloc.h>
#include <sys/mman.h>
#include <sys/mount.h>
#include <sys/proc.h>
#include <sys/sbuf.h>
#include <sys/systm.h>
#include <sys/sysproto.h>
#include <sys/sysent.h>
#include <sys/systm.h>
#include <sys/vnode.h>
#include <sys/file.h>
#include <sys/socket.h>
#include <sys/socketvar.h>
#include <sys/pipe.h>
#include <sys/sx.h>
#include <sys/sysctl.h>
#include <sys/msg.h>
#include <sys/sem.h>
#include <sys/shm.h>

#include <fs/devfs/devfs.h>

#include <net/bpfdesc.h>
#include <net/if.h>
#include <net/if_types.h>
#include <net/if_var.h>

#include <netinet/in.h>
#include <netinet/in_pcb.h>
#include <netinet/ip_var.h>

#include <vm/uma.h>
#include <vm/vm.h>

#include <security/mac/mac_policy.h>
#include <security/mac_biba/mac_biba.h>

SYSCTL_DECL(_security_mac);

SYSCTL_NODE(_security_mac, OID_AUTO, biba, CTLFLAG_RW, 0,
    "TrustedBSD mac_biba policy controls");

static int	mac_biba_label_size = sizeof(struct mac_biba);
SYSCTL_INT(_security_mac_biba, OID_AUTO, label_size, CTLFLAG_RD,
    &mac_biba_label_size, 0, "Size of struct mac_biba");

static int	mac_biba_enabled = 1;
SYSCTL_INT(_security_mac_biba, OID_AUTO, enabled, CTLFLAG_RW,
    &mac_biba_enabled, 0, "Enforce MAC/Biba policy");
TUNABLE_INT("security.mac.biba.enabled", &mac_biba_enabled);

static int	destroyed_not_inited;
SYSCTL_INT(_security_mac_biba, OID_AUTO, destroyed_not_inited, CTLFLAG_RD,
    &destroyed_not_inited, 0, "Count of labels destroyed but not inited");

static int	trust_all_interfaces = 0;
SYSCTL_INT(_security_mac_biba, OID_AUTO, trust_all_interfaces, CTLFLAG_RD,
    &trust_all_interfaces, 0, "Consider all interfaces 'trusted' by MAC/Biba");
TUNABLE_INT("security.mac.biba.trust_all_interfaces", &trust_all_interfaces);

static char	trusted_interfaces[128];
SYSCTL_STRING(_security_mac_biba, OID_AUTO, trusted_interfaces, CTLFLAG_RD,
    trusted_interfaces, 0, "Interfaces considered 'trusted' by MAC/Biba");
TUNABLE_STR("security.mac.biba.trusted_interfaces", trusted_interfaces,
    sizeof(trusted_interfaces));

static int	max_compartments = MAC_BIBA_MAX_COMPARTMENTS;
SYSCTL_INT(_security_mac_biba, OID_AUTO, max_compartments, CTLFLAG_RD,
    &max_compartments, 0, "Maximum supported compartments");

static int	ptys_equal = 0;
SYSCTL_INT(_security_mac_biba, OID_AUTO, ptys_equal, CTLFLAG_RW,
    &ptys_equal, 0, "Label pty devices as biba/equal on create");
TUNABLE_INT("security.mac.biba.ptys_equal", &ptys_equal);

static int	interfaces_equal;
SYSCTL_INT(_security_mac_biba, OID_AUTO, interfaces_equal, CTLFLAG_RW,
    &interfaces_equal, 0, "Label network interfaces as biba/equal on create");
TUNABLE_INT("security.mac.biba.interfaces_equal", &interfaces_equal);

static int	revocation_enabled = 0;
SYSCTL_INT(_security_mac_biba, OID_AUTO, revocation_enabled, CTLFLAG_RW,
    &revocation_enabled, 0, "Revoke access to objects on relabel");
TUNABLE_INT("security.mac.biba.revocation_enabled", &revocation_enabled);

static int	mac_biba_slot;
#define	SLOT(l)	((struct mac_biba *)mac_label_get((l), mac_biba_slot))
#define	SLOT_SET(l, val) mac_label_set((l), mac_biba_slot, (uintptr_t)(val))

static uma_zone_t	zone_biba;

static __inline int
biba_bit_set_empty(u_char *set) {
	int i;

	for (i = 0; i < MAC_BIBA_MAX_COMPARTMENTS >> 3; i++)
		if (set[i] != 0)
			return (0);
	return (1);
}

static struct mac_biba *
biba_alloc(int flag)
{

	return (uma_zalloc(zone_biba, flag | M_ZERO));
}

static void
biba_free(struct mac_biba *mac_biba)
{

	if (mac_biba != NULL)
		uma_zfree(zone_biba, mac_biba);
	else
		atomic_add_int(&destroyed_not_inited, 1);
}

static int
biba_atmostflags(struct mac_biba *mac_biba, int flags)
{

	if ((mac_biba->mb_flags & flags) != mac_biba->mb_flags)
		return (EINVAL);
	return (0);
}

static int
mac_biba_dominate_element(struct mac_biba_element *a,
    struct mac_biba_element *b)
{
	int bit;

	switch (a->mbe_type) {
	case MAC_BIBA_TYPE_EQUAL:
	case MAC_BIBA_TYPE_HIGH:
		return (1);

	case MAC_BIBA_TYPE_LOW:
		switch (b->mbe_type) {
		case MAC_BIBA_TYPE_GRADE:
		case MAC_BIBA_TYPE_HIGH:
			return (0);

		case MAC_BIBA_TYPE_EQUAL:
		case MAC_BIBA_TYPE_LOW:
			return (1);

		default:
			panic("mac_biba_dominate_element: b->mbe_type invalid");
		}

	case MAC_BIBA_TYPE_GRADE:
		switch (b->mbe_type) {
		case MAC_BIBA_TYPE_EQUAL:
		case MAC_BIBA_TYPE_LOW:
			return (1);

		case MAC_BIBA_TYPE_HIGH:
			return (0);

		case MAC_BIBA_TYPE_GRADE:
			for (bit = 1; bit <= MAC_BIBA_MAX_COMPARTMENTS; bit++)
				if (!MAC_BIBA_BIT_TEST(bit,
				    a->mbe_compartments) &&
				    MAC_BIBA_BIT_TEST(bit, b->mbe_compartments))
					return (0);
			return (a->mbe_grade >= b->mbe_grade);

		default:
			panic("mac_biba_dominate_element: b->mbe_type invalid");
		}

	default:
		panic("mac_biba_dominate_element: a->mbe_type invalid");
	}

	return (0);
}

static int
mac_biba_subject_dominate_high(struct mac_biba *mac_biba)
{
	struct mac_biba_element *element;

	KASSERT((mac_biba->mb_flags & MAC_BIBA_FLAG_EFFECTIVE) != 0,
	    ("mac_biba_effective_in_range: mac_biba not effective"));
	element = &mac_biba->mb_effective;

	return (element->mbe_type == MAC_BIBA_TYPE_EQUAL ||
	    element->mbe_type == MAC_BIBA_TYPE_HIGH);
}

static int
mac_biba_range_in_range(struct mac_biba *rangea, struct mac_biba *rangeb)
{

	return (mac_biba_dominate_element(&rangeb->mb_rangehigh,
	    &rangea->mb_rangehigh) &&
	    mac_biba_dominate_element(&rangea->mb_rangelow,
	    &rangeb->mb_rangelow));
}

static int
mac_biba_effective_in_range(struct mac_biba *effective,
    struct mac_biba *range)
{

	KASSERT((effective->mb_flags & MAC_BIBA_FLAG_EFFECTIVE) != 0,
	    ("mac_biba_effective_in_range: a not effective"));
	KASSERT((range->mb_flags & MAC_BIBA_FLAG_RANGE) != 0,
	    ("mac_biba_effective_in_range: b not range"));

	return (mac_biba_dominate_element(&range->mb_rangehigh,
	    &effective->mb_effective) &&
	    mac_biba_dominate_element(&effective->mb_effective,
	    &range->mb_rangelow));

	return (1);
}

static int
mac_biba_dominate_effective(struct mac_biba *a, struct mac_biba *b)
{
	KASSERT((a->mb_flags & MAC_BIBA_FLAG_EFFECTIVE) != 0,
	    ("mac_biba_dominate_effective: a not effective"));
	KASSERT((b->mb_flags & MAC_BIBA_FLAG_EFFECTIVE) != 0,
	    ("mac_biba_dominate_effective: b not effective"));

	return (mac_biba_dominate_element(&a->mb_effective, &b->mb_effective));
}

static int
mac_biba_equal_element(struct mac_biba_element *a, struct mac_biba_element *b)
{

	if (a->mbe_type == MAC_BIBA_TYPE_EQUAL ||
	    b->mbe_type == MAC_BIBA_TYPE_EQUAL)
		return (1);

	return (a->mbe_type == b->mbe_type && a->mbe_grade == b->mbe_grade);
}

static int
mac_biba_equal_effective(struct mac_biba *a, struct mac_biba *b)
{

	KASSERT((a->mb_flags & MAC_BIBA_FLAG_EFFECTIVE) != 0,
	    ("mac_biba_equal_effective: a not effective"));
	KASSERT((b->mb_flags & MAC_BIBA_FLAG_EFFECTIVE) != 0,
	    ("mac_biba_equal_effective: b not effective"));

	return (mac_biba_equal_element(&a->mb_effective, &b->mb_effective));
}

static int
mac_biba_contains_equal(struct mac_biba *mac_biba)
{

	if (mac_biba->mb_flags & MAC_BIBA_FLAG_EFFECTIVE)
		if (mac_biba->mb_effective.mbe_type == MAC_BIBA_TYPE_EQUAL)
			return (1);

	if (mac_biba->mb_flags & MAC_BIBA_FLAG_RANGE) {
		if (mac_biba->mb_rangelow.mbe_type == MAC_BIBA_TYPE_EQUAL)
			return (1);
		if (mac_biba->mb_rangehigh.mbe_type == MAC_BIBA_TYPE_EQUAL)
			return (1);
	}

	return (0);
}

static int
mac_biba_subject_privileged(struct mac_biba *mac_biba)
{

	KASSERT((mac_biba->mb_flags & MAC_BIBA_FLAGS_BOTH) ==
	    MAC_BIBA_FLAGS_BOTH,
	    ("mac_biba_subject_privileged: subject doesn't have both labels"));

	/* If the effective is EQUAL, it's ok. */
	if (mac_biba->mb_effective.mbe_type == MAC_BIBA_TYPE_EQUAL)
		return (0);

	/* If either range endpoint is EQUAL, it's ok. */
	if (mac_biba->mb_rangelow.mbe_type == MAC_BIBA_TYPE_EQUAL ||
	    mac_biba->mb_rangehigh.mbe_type == MAC_BIBA_TYPE_EQUAL)
		return (0);

	/* If the range is low-high, it's ok. */
	if (mac_biba->mb_rangelow.mbe_type == MAC_BIBA_TYPE_LOW &&
	    mac_biba->mb_rangehigh.mbe_type == MAC_BIBA_TYPE_HIGH)
		return (0);

	/* It's not ok. */
	return (EPERM);
}

static int
mac_biba_high_effective(struct mac_biba *mac_biba)
{

	KASSERT((mac_biba->mb_flags & MAC_BIBA_FLAG_EFFECTIVE) != 0,
	    ("mac_biba_equal_effective: mac_biba not effective"));

	return (mac_biba->mb_effective.mbe_type == MAC_BIBA_TYPE_HIGH);
}

static int
mac_biba_valid(struct mac_biba *mac_biba)
{

	if (mac_biba->mb_flags & MAC_BIBA_FLAG_EFFECTIVE) {
		switch (mac_biba->mb_effective.mbe_type) {
		case MAC_BIBA_TYPE_GRADE:
			break;

		case MAC_BIBA_TYPE_EQUAL:
		case MAC_BIBA_TYPE_HIGH:
		case MAC_BIBA_TYPE_LOW:
			if (mac_biba->mb_effective.mbe_grade != 0 ||
			    !MAC_BIBA_BIT_SET_EMPTY(
			    mac_biba->mb_effective.mbe_compartments))
				return (EINVAL);
			break;

		default:
			return (EINVAL);
		}
	} else {
		if (mac_biba->mb_effective.mbe_type != MAC_BIBA_TYPE_UNDEF)
			return (EINVAL);
	}

	if (mac_biba->mb_flags & MAC_BIBA_FLAG_RANGE) {
		switch (mac_biba->mb_rangelow.mbe_type) {
		case MAC_BIBA_TYPE_GRADE:
			break;

		case MAC_BIBA_TYPE_EQUAL:
		case MAC_BIBA_TYPE_HIGH:
		case MAC_BIBA_TYPE_LOW:
			if (mac_biba->mb_rangelow.mbe_grade != 0 ||
			    !MAC_BIBA_BIT_SET_EMPTY(
			    mac_biba->mb_rangelow.mbe_compartments))
				return (EINVAL);
			break;

		default:
			return (EINVAL);
		}

		switch (mac_biba->mb_rangehigh.mbe_type) {
		case MAC_BIBA_TYPE_GRADE:
			break;

		case MAC_BIBA_TYPE_EQUAL:
		case MAC_BIBA_TYPE_HIGH:
		case MAC_BIBA_TYPE_LOW:
			if (mac_biba->mb_rangehigh.mbe_grade != 0 ||
			    !MAC_BIBA_BIT_SET_EMPTY(
			    mac_biba->mb_rangehigh.mbe_compartments))
				return (EINVAL);
			break;

		default:
			return (EINVAL);
		}
		if (!mac_biba_dominate_element(&mac_biba->mb_rangehigh,
		    &mac_biba->mb_rangelow))
			return (EINVAL);
	} else {
		if (mac_biba->mb_rangelow.mbe_type != MAC_BIBA_TYPE_UNDEF ||
		    mac_biba->mb_rangehigh.mbe_type != MAC_BIBA_TYPE_UNDEF)
			return (EINVAL);
	}

	return (0);
}

static void
mac_biba_set_range(struct mac_biba *mac_biba, u_short typelow,
    u_short gradelow, u_char *compartmentslow, u_short typehigh,
    u_short gradehigh, u_char *compartmentshigh)
{

	mac_biba->mb_rangelow.mbe_type = typelow;
	mac_biba->mb_rangelow.mbe_grade = gradelow;
	if (compartmentslow != NULL)
		memcpy(mac_biba->mb_rangelow.mbe_compartments,
		    compartmentslow,
		    sizeof(mac_biba->mb_rangelow.mbe_compartments));
	mac_biba->mb_rangehigh.mbe_type = typehigh;
	mac_biba->mb_rangehigh.mbe_grade = gradehigh;
	if (compartmentshigh != NULL)
		memcpy(mac_biba->mb_rangehigh.mbe_compartments,
		    compartmentshigh,
		    sizeof(mac_biba->mb_rangehigh.mbe_compartments));
	mac_biba->mb_flags |= MAC_BIBA_FLAG_RANGE;
}

static void
mac_biba_set_effective(struct mac_biba *mac_biba, u_short type, u_short grade,
    u_char *compartments)
{

	mac_biba->mb_effective.mbe_type = type;
	mac_biba->mb_effective.mbe_grade = grade;
	if (compartments != NULL)
		memcpy(mac_biba->mb_effective.mbe_compartments, compartments,
		    sizeof(mac_biba->mb_effective.mbe_compartments));
	mac_biba->mb_flags |= MAC_BIBA_FLAG_EFFECTIVE;
}

static void
mac_biba_copy_range(struct mac_biba *labelfrom, struct mac_biba *labelto)
{

	KASSERT((labelfrom->mb_flags & MAC_BIBA_FLAG_RANGE) != 0,
	    ("mac_biba_copy_range: labelfrom not range"));

	labelto->mb_rangelow = labelfrom->mb_rangelow;
	labelto->mb_rangehigh = labelfrom->mb_rangehigh;
	labelto->mb_flags |= MAC_BIBA_FLAG_RANGE;
}

static void
mac_biba_copy_effective(struct mac_biba *labelfrom, struct mac_biba *labelto)
{

	KASSERT((labelfrom->mb_flags & MAC_BIBA_FLAG_EFFECTIVE) != 0,
	    ("mac_biba_copy_effective: labelfrom not effective"));

	labelto->mb_effective = labelfrom->mb_effective;
	labelto->mb_flags |= MAC_BIBA_FLAG_EFFECTIVE;
}

static void
mac_biba_copy(struct mac_biba *source, struct mac_biba *dest)
{

	if (source->mb_flags & MAC_BIBA_FLAG_EFFECTIVE)
		mac_biba_copy_effective(source, dest);
	if (source->mb_flags & MAC_BIBA_FLAG_RANGE)
		mac_biba_copy_range(source, dest);
}

/*
 * Policy module operations.
 */
static void
mac_biba_init(struct mac_policy_conf *conf)
{

	zone_biba = uma_zcreate("mac_biba", sizeof(struct mac_biba), NULL,
	    NULL, NULL, NULL, UMA_ALIGN_PTR, 0);
}

/*
 * Label operations.
 */
static void
mac_biba_init_label(struct label *label)
{

	SLOT_SET(label, biba_alloc(M_WAITOK));
}

static int
mac_biba_init_label_waitcheck(struct label *label, int flag)
{

	SLOT_SET(label, biba_alloc(flag));
	if (SLOT(label) == NULL)
		return (ENOMEM);

	return (0);
}

static void
mac_biba_destroy_label(struct label *label)
{

	biba_free(SLOT(label));
	SLOT_SET(label, NULL);
}

/*
 * mac_biba_element_to_string() accepts an sbuf and Biba element.  It
 * converts the Biba element to a string and stores the result in the
 * sbuf; if there isn't space in the sbuf, -1 is returned.
 */
static int
mac_biba_element_to_string(struct sbuf *sb, struct mac_biba_element *element)
{
	int i, first;

	switch (element->mbe_type) {
	case MAC_BIBA_TYPE_HIGH:
		return (sbuf_printf(sb, "high"));

	case MAC_BIBA_TYPE_LOW:
		return (sbuf_printf(sb, "low"));

	case MAC_BIBA_TYPE_EQUAL:
		return (sbuf_printf(sb, "equal"));

	case MAC_BIBA_TYPE_GRADE:
		if (sbuf_printf(sb, "%d", element->mbe_grade) == -1)
			return (-1);

		first = 1;
		for (i = 1; i <= MAC_BIBA_MAX_COMPARTMENTS; i++) {
			if (MAC_BIBA_BIT_TEST(i, element->mbe_compartments)) {
				if (first) {
					if (sbuf_putc(sb, ':') == -1)
						return (-1);
					if (sbuf_printf(sb, "%d", i) == -1)
						return (-1);
					first = 0;
				} else {
					if (sbuf_printf(sb, "+%d", i) == -1)
						return (-1);
				}
			}
		}
		return (0);

	default:
		panic("mac_biba_element_to_string: invalid type (%d)",
		    element->mbe_type);
	}
}

/*
 * mac_biba_to_string() converts a Biba label to a string, and places
 * the results in the passed sbuf.  It returns 0 on success, or EINVAL
 * if there isn't room in the sbuf.  Note: the sbuf will be modified
 * even in a failure case, so the caller may need to revert the sbuf
 * by restoring the offset if that's undesired.
 */
static int
mac_biba_to_string(struct sbuf *sb, struct mac_biba *mac_biba)
{

	if (mac_biba->mb_flags & MAC_BIBA_FLAG_EFFECTIVE) {
		if (mac_biba_element_to_string(sb, &mac_biba->mb_effective)
		    == -1)
			return (EINVAL);
	}

	if (mac_biba->mb_flags & MAC_BIBA_FLAG_RANGE) {
		if (sbuf_putc(sb, '(') == -1)
			return (EINVAL);

		if (mac_biba_element_to_string(sb, &mac_biba->mb_rangelow)
		    == -1)
			return (EINVAL);

		if (sbuf_putc(sb, '-') == -1)
			return (EINVAL);

		if (mac_biba_element_to_string(sb, &mac_biba->mb_rangehigh)
		    == -1)
			return (EINVAL);

		if (sbuf_putc(sb, ')') == -1)
			return (EINVAL);
	}

	return (0);
}

static int
mac_biba_externalize_label(struct label *label, char *element_name,
    struct sbuf *sb, int *claimed)
{
	struct mac_biba *mac_biba;

	if (strcmp(MAC_BIBA_LABEL_NAME, element_name) != 0)
		return (0);

	(*claimed)++;

	mac_biba = SLOT(label);
	return (mac_biba_to_string(sb, mac_biba));
}

static int
mac_biba_parse_element(struct mac_biba_element *element, char *string)
{
	char *compartment, *end, *grade;
	int value;

	if (strcmp(string, "high") == 0 ||
	    strcmp(string, "hi") == 0) {
		element->mbe_type = MAC_BIBA_TYPE_HIGH;
		element->mbe_grade = MAC_BIBA_TYPE_UNDEF;
	} else if (strcmp(string, "low") == 0 ||
	    strcmp(string, "lo") == 0) {
		element->mbe_type = MAC_BIBA_TYPE_LOW;
		element->mbe_grade = MAC_BIBA_TYPE_UNDEF;
	} else if (strcmp(string, "equal") == 0 ||
	    strcmp(string, "eq") == 0) {
		element->mbe_type = MAC_BIBA_TYPE_EQUAL;
		element->mbe_grade = MAC_BIBA_TYPE_UNDEF;
	} else {
		element->mbe_type = MAC_BIBA_TYPE_GRADE;

		/*
		 * Numeric grade piece of the element.
		 */
		grade = strsep(&string, ":");
		value = strtol(grade, &end, 10);
		if (end == grade || *end != '\0')
			return (EINVAL);
		if (value < 0 || value > 65535)
			return (EINVAL);
		element->mbe_grade = value;

		/*
		 * Optional compartment piece of the element.  If none
		 * are included, we assume that the label has no
		 * compartments.
		 */
		if (string == NULL)
			return (0);
		if (*string == '\0')
			return (0);

		while ((compartment = strsep(&string, "+")) != NULL) {
			value = strtol(compartment, &end, 10);
			if (compartment == end || *end != '\0')
				return (EINVAL);
			if (value < 1 || value > MAC_BIBA_MAX_COMPARTMENTS)
				return (EINVAL);
			MAC_BIBA_BIT_SET(value, element->mbe_compartments);
		}
	}

	return (0);
}

/*
 * Note: destructively consumes the string, make a local copy before
 * calling if that's a problem.
 */
static int
mac_biba_parse(struct mac_biba *mac_biba, char *string)
{
	char *rangehigh, *rangelow, *effective;
	int error;

	effective = strsep(&string, "(");
	if (*effective == '\0')
		effective = NULL;

	if (string != NULL) {
		rangelow = strsep(&string, "-");
		if (string == NULL)
			return (EINVAL);
		rangehigh = strsep(&string, ")");
		if (string == NULL)
			return (EINVAL);
		if (*string != '\0')
			return (EINVAL);
	} else {
		rangelow = NULL;
		rangehigh = NULL;
	}

	KASSERT((rangelow != NULL && rangehigh != NULL) ||
	    (rangelow == NULL && rangehigh == NULL),
	    ("mac_biba_parse: range mismatch"));

	bzero(mac_biba, sizeof(*mac_biba));
	if (effective != NULL) {
		error = mac_biba_parse_element(&mac_biba->mb_effective, effective);
		if (error)
			return (error);
		mac_biba->mb_flags |= MAC_BIBA_FLAG_EFFECTIVE;
	}

	if (rangelow != NULL) {
		error = mac_biba_parse_element(&mac_biba->mb_rangelow,
		    rangelow);
		if (error)
			return (error);
		error = mac_biba_parse_element(&mac_biba->mb_rangehigh,
		    rangehigh);
		if (error)
			return (error);
		mac_biba->mb_flags |= MAC_BIBA_FLAG_RANGE;
	}

	error = mac_biba_valid(mac_biba);
	if (error)
		return (error);

	return (0);
}

static int
mac_biba_internalize_label(struct label *label, char *element_name,
    char *element_data, int *claimed)
{
	struct mac_biba *mac_biba, mac_biba_temp;
	int error;

	if (strcmp(MAC_BIBA_LABEL_NAME, element_name) != 0)
		return (0);

	(*claimed)++;

	error = mac_biba_parse(&mac_biba_temp, element_data);
	if (error)
		return (error);

	mac_biba = SLOT(label);
	*mac_biba = mac_biba_temp;

	return (0);
}

static void
mac_biba_copy_label(struct label *src, struct label *dest)
{

	*SLOT(dest) = *SLOT(src);
}

/*
 * Labeling event operations: file system objects, and things that look
 * a lot like file system objects.
 */
static void
mac_biba_create_devfs_device(struct ucred *cred, struct mount *mp,
    struct cdev *dev, struct devfs_dirent *devfs_dirent, struct label *label)
{
	struct mac_biba *mac_biba;
	int biba_type;

	mac_biba = SLOT(label);
	if (strcmp(dev->si_name, "null") == 0 ||
	    strcmp(dev->si_name, "zero") == 0 ||
	    strcmp(dev->si_name, "random") == 0 ||
	    strncmp(dev->si_name, "fd/", strlen("fd/")) == 0)
		biba_type = MAC_BIBA_TYPE_EQUAL;
	else if (ptys_equal &&
	    (strncmp(dev->si_name, "ttyp", strlen("ttyp")) == 0 ||
	    strncmp(dev->si_name, "ptyp", strlen("ptyp")) == 0))
		biba_type = MAC_BIBA_TYPE_EQUAL;
	else
		biba_type = MAC_BIBA_TYPE_HIGH;
	mac_biba_set_effective(mac_biba, biba_type, 0, NULL);
}

static void
mac_biba_create_devfs_directory(struct mount *mp, char *dirname,
    int dirnamelen, struct devfs_dirent *devfs_dirent, struct label *label)
{
	struct mac_biba *mac_biba;

	mac_biba = SLOT(label);
	mac_biba_set_effective(mac_biba, MAC_BIBA_TYPE_HIGH, 0, NULL);
}

static void
mac_biba_create_devfs_symlink(struct ucred *cred, struct mount *mp,
    struct devfs_dirent *dd, struct label *ddlabel, struct devfs_dirent *de,
    struct label *delabel)
{
	struct mac_biba *source, *dest;

	source = SLOT(cred->cr_label);
	dest = SLOT(delabel);

	mac_biba_copy_effective(source, dest);
}

static void
mac_biba_create_mount(struct ucred *cred, struct mount *mp,
    struct label *mntlabel, struct label *fslabel)
{
	struct mac_biba *source, *dest;

	source = SLOT(cred->cr_label);
	dest = SLOT(mntlabel);
	mac_biba_copy_effective(source, dest);
	dest = SLOT(fslabel);
	mac_biba_copy_effective(source, dest);
}

static void
mac_biba_relabel_vnode(struct ucred *cred, struct vnode *vp,
    struct label *vnodelabel, struct label *label)
{
	struct mac_biba *source, *dest;

	source = SLOT(label);
	dest = SLOT(vnodelabel);

	mac_biba_copy(source, dest);
}

static void
mac_biba_update_devfsdirent(struct mount *mp,
    struct devfs_dirent *devfs_dirent, struct label *direntlabel,
    struct vnode *vp, struct label *vnodelabel)
{
	struct mac_biba *source, *dest;

	source = SLOT(vnodelabel);
	dest = SLOT(direntlabel);

	mac_biba_copy(source, dest);
}

static void
mac_biba_associate_vnode_devfs(struct mount *mp, struct label *fslabel,
    struct devfs_dirent *de, struct label *delabel, struct vnode *vp,
    struct label *vlabel)
{
	struct mac_biba *source, *dest;

	source = SLOT(delabel);
	dest = SLOT(vlabel);

	mac_biba_copy_effective(source, dest);
}

static int
mac_biba_associate_vnode_extattr(struct mount *mp, struct label *fslabel,
    struct vnode *vp, struct label *vlabel)
{
	struct mac_biba temp, *source, *dest;
	int buflen, error;

	source = SLOT(fslabel);
	dest = SLOT(vlabel);

	buflen = sizeof(temp);
	bzero(&temp, buflen);

	error = vn_extattr_get(vp, IO_NODELOCKED, MAC_BIBA_EXTATTR_NAMESPACE,
	    MAC_BIBA_EXTATTR_NAME, &buflen, (char *) &temp, curthread);
	if (error == ENOATTR || error == EOPNOTSUPP) {
		/* Fall back to the fslabel. */
		mac_biba_copy_effective(source, dest);
		return (0);
	} else if (error)
		return (error);

	if (buflen != sizeof(temp)) {
		printf("mac_biba_associate_vnode_extattr: bad size %d\n",
		    buflen);
		return (EPERM);
	}
	if (mac_biba_valid(&temp) != 0) {
		printf("mac_biba_associate_vnode_extattr: invalid\n");
		return (EPERM);
	}
	if ((temp.mb_flags & MAC_BIBA_FLAGS_BOTH) != MAC_BIBA_FLAG_EFFECTIVE) {
		printf("mac_biba_associate_vnode_extattr: not effective\n");
		return (EPERM);
	}

	mac_biba_copy_effective(&temp, dest);
	return (0);
}

static void
mac_biba_associate_vnode_singlelabel(struct mount *mp,
    struct label *fslabel, struct vnode *vp, struct label *vlabel)
{
	struct mac_biba *source, *dest;

	source = SLOT(fslabel);
	dest = SLOT(vlabel);

	mac_biba_copy_effective(source, dest);
}

static int
mac_biba_create_vnode_extattr(struct ucred *cred, struct mount *mp,
    struct label *fslabel, struct vnode *dvp, struct label *dlabel,
    struct vnode *vp, struct label *vlabel, struct componentname *cnp)
{
	struct mac_biba *source, *dest, temp;
	size_t buflen;
	int error;

	buflen = sizeof(temp);
	bzero(&temp, buflen);

	source = SLOT(cred->cr_label);
	dest = SLOT(vlabel);
	mac_biba_copy_effective(source, &temp);

	error = vn_extattr_set(vp, IO_NODELOCKED, MAC_BIBA_EXTATTR_NAMESPACE,
	    MAC_BIBA_EXTATTR_NAME, buflen, (char *) &temp, curthread);
	if (error == 0)
		mac_biba_copy_effective(source, dest);
	return (error);
}

static int
mac_biba_setlabel_vnode_extattr(struct ucred *cred, struct vnode *vp,
    struct label *vlabel, struct label *intlabel)
{
	struct mac_biba *source, temp;
	size_t buflen;
	int error;

	buflen = sizeof(temp);
	bzero(&temp, buflen);

	source = SLOT(intlabel);
	if ((source->mb_flags & MAC_BIBA_FLAG_EFFECTIVE) == 0)
		return (0);

	mac_biba_copy_effective(source, &temp);

	error = vn_extattr_set(vp, IO_NODELOCKED, MAC_BIBA_EXTATTR_NAMESPACE,
	    MAC_BIBA_EXTATTR_NAME, buflen, (char *) &temp, curthread);
	return (error);
}

/*
 * Labeling event operations: IPC object.
 */
static void
mac_biba_create_inpcb_from_socket(struct socket *so, struct label *solabel,
    struct inpcb *inp, struct label *inplabel)
{
	struct mac_biba *source, *dest;

	source = SLOT(solabel);
	dest = SLOT(inplabel);

	mac_biba_copy_effective(source, dest);
}

static void
mac_biba_create_mbuf_from_socket(struct socket *so, struct label *socketlabel,
    struct mbuf *m, struct label *mbuflabel)
{
	struct mac_biba *source, *dest;

	source = SLOT(socketlabel);
	dest = SLOT(mbuflabel);

	mac_biba_copy_effective(source, dest);
}

static void
mac_biba_create_socket(struct ucred *cred, struct socket *socket,
    struct label *socketlabel)
{
	struct mac_biba *source, *dest;

	source = SLOT(cred->cr_label);
	dest = SLOT(socketlabel);

	mac_biba_copy_effective(source, dest);
}

static void
mac_biba_create_pipe(struct ucred *cred, struct pipepair *pp,
    struct label *pipelabel)
{
	struct mac_biba *source, *dest;

	source = SLOT(cred->cr_label);
	dest = SLOT(pipelabel);

	mac_biba_copy_effective(source, dest);
}

static void
mac_biba_create_posix_sem(struct ucred *cred, struct ksem *ksemptr,
    struct label *ks_label)
{
	struct mac_biba *source, *dest;

	source = SLOT(cred->cr_label);
	dest = SLOT(ks_label);

	mac_biba_copy_effective(source, dest);
}

static void
mac_biba_create_socket_from_socket(struct socket *oldsocket,
    struct label *oldsocketlabel, struct socket *newsocket,
    struct label *newsocketlabel)
{
	struct mac_biba *source, *dest;

	source = SLOT(oldsocketlabel);
	dest = SLOT(newsocketlabel);

	mac_biba_copy_effective(source, dest);
}

static void
mac_biba_relabel_socket(struct ucred *cred, struct socket *socket,
    struct label *socketlabel, struct label *newlabel)
{
	struct mac_biba *source, *dest;

	source = SLOT(newlabel);
	dest = SLOT(socketlabel);

	mac_biba_copy(source, dest);
}

static void
mac_biba_relabel_pipe(struct ucred *cred, struct pipepair *pp,
    struct label *pipelabel, struct label *newlabel)
{
	struct mac_biba *source, *dest;

	source = SLOT(newlabel);
	dest = SLOT(pipelabel);

	mac_biba_copy(source, dest);
}

static void
mac_biba_set_socket_peer_from_mbuf(struct mbuf *mbuf, struct label *mbuflabel,
    struct socket *socket, struct label *socketpeerlabel)
{
	struct mac_biba *source, *dest;

	source = SLOT(mbuflabel);
	dest = SLOT(socketpeerlabel);

	mac_biba_copy_effective(source, dest);
}

/*
 * Labeling event operations: System V IPC objects.
 */

static void
mac_biba_create_sysv_msgmsg(struct ucred *cred, struct msqid_kernel *msqkptr,
    struct label *msqlabel, struct msg *msgptr, struct label *msglabel)
{
	struct mac_biba *source, *dest;

	/* Ignore the msgq label */
	source = SLOT(cred->cr_label);
	dest = SLOT(msglabel);

	mac_biba_copy_effective(source, dest);
}

static void
mac_biba_create_sysv_msgqueue(struct ucred *cred,
    struct msqid_kernel *msqkptr, struct label *msqlabel)
{
	struct mac_biba *source, *dest;

	source = SLOT(cred->cr_label);
	dest = SLOT(msqlabel);

	mac_biba_copy_effective(source, dest);
}

static void
mac_biba_create_sysv_sem(struct ucred *cred, struct semid_kernel *semakptr,
    struct label *semalabel)
{
	struct mac_biba *source, *dest;

	source = SLOT(cred->cr_label);
	dest = SLOT(semalabel);

	mac_biba_copy_effective(source, dest);
}

static void
mac_biba_create_sysv_shm(struct ucred *cred, struct shmid_kernel *shmsegptr,
    struct label *shmlabel)
{
	struct mac_biba *source, *dest;

	source = SLOT(cred->cr_label);
	dest = SLOT(shmlabel);

	mac_biba_copy_effective(source, dest);
}

/*
 * Labeling event operations: network objects.
 */
static void
mac_biba_set_socket_peer_from_socket(struct socket *oldsocket,
    struct label *oldsocketlabel, struct socket *newsocket,
    struct label *newsocketpeerlabel)
{
	struct mac_biba *source, *dest;

	source = SLOT(oldsocketlabel);
	dest = SLOT(newsocketpeerlabel);

	mac_biba_copy_effective(source, dest);
}

static void
mac_biba_create_bpfdesc(struct ucred *cred, struct bpf_d *bpf_d,
    struct label *bpflabel)
{
	struct mac_biba *source, *dest;

	source = SLOT(cred->cr_label);
	dest = SLOT(bpflabel);

	mac_biba_copy_effective(source, dest);
}

static void
mac_biba_create_ifnet(struct ifnet *ifnet, struct label *ifnetlabel)
{
	char tifname[IFNAMSIZ], *p, *q;
	char tiflist[sizeof(trusted_interfaces)];
	struct mac_biba *dest;
	int len, type;

	dest = SLOT(ifnetlabel);

	if (ifnet->if_type == IFT_LOOP || interfaces_equal != 0) {
		type = MAC_BIBA_TYPE_EQUAL;
		goto set;
	}

	if (trust_all_interfaces) {
		type = MAC_BIBA_TYPE_HIGH;
		goto set;
	}

	type = MAC_BIBA_TYPE_LOW;

	if (trusted_interfaces[0] == '\0' ||
	    !strvalid(trusted_interfaces, sizeof(trusted_interfaces)))
		goto set;

	bzero(tiflist, sizeof(tiflist));
	for (p = trusted_interfaces, q = tiflist; *p != '\0'; p++, q++)
		if(*p != ' ' && *p != '\t')
			*q = *p;

	for (p = q = tiflist;; p++) {
		if (*p == ',' || *p == '\0') {
			len = p - q;
			if (len < IFNAMSIZ) {
				bzero(tifname, sizeof(tifname));
				bcopy(q, tifname, len);
				if (strcmp(tifname, ifnet->if_xname) == 0) {
					type = MAC_BIBA_TYPE_HIGH;
					break;
				}
			} else {
				*p = '\0';
				printf("mac_biba warning: interface name "
				    "\"%s\" is too long (must be < %d)\n",
				    q, IFNAMSIZ);
			}
			if (*p == '\0')
				break;
			q = p + 1;
		}
	}
set:
	mac_biba_set_effective(dest, type, 0, NULL);
	mac_biba_set_range(dest, type, 0, NULL, type, 0, NULL);
}

static void
mac_biba_create_ipq(struct mbuf *fragment, struct label *fragmentlabel,
    struct ipq *ipq, struct label *ipqlabel)
{
	struct mac_biba *source, *dest;

	source = SLOT(fragmentlabel);
	dest = SLOT(ipqlabel);

	mac_biba_copy_effective(source, dest);
}

static void
mac_biba_create_datagram_from_ipq(struct ipq *ipq, struct label *ipqlabel,
    struct mbuf *datagram, struct label *datagramlabel)
{
	struct mac_biba *source, *dest;

	source = SLOT(ipqlabel);
	dest = SLOT(datagramlabel);

	/* Just use the head, since we require them all to match. */
	mac_biba_copy_effective(source, dest);
}

static void
mac_biba_create_fragment(struct mbuf *datagram, struct label *datagramlabel,
    struct mbuf *fragment, struct label *fragmentlabel)
{
	struct mac_biba *source, *dest;

	source = SLOT(datagramlabel);
	dest = SLOT(fragmentlabel);

	mac_biba_copy_effective(source, dest);
}

static void
mac_biba_create_mbuf_from_inpcb(struct inpcb *inp, struct label *inplabel,
    struct mbuf *m, struct label *mlabel)
{
	struct mac_biba *source, *dest;

	source = SLOT(inplabel);
	dest = SLOT(mlabel);

	mac_biba_copy_effective(source, dest);
}

static void
mac_biba_create_mbuf_linklayer(struct ifnet *ifnet, struct label *ifnetlabel,
    struct mbuf *mbuf, struct label *mbuflabel)
{
	struct mac_biba *dest;

	dest = SLOT(mbuflabel);

	mac_biba_set_effective(dest, MAC_BIBA_TYPE_EQUAL, 0, NULL);
}

static void
mac_biba_create_mbuf_from_bpfdesc(struct bpf_d *bpf_d, struct label *bpflabel,
    struct mbuf *mbuf, struct label *mbuflabel)
{
	struct mac_biba *source, *dest;

	source = SLOT(bpflabel);
	dest = SLOT(mbuflabel);

	mac_biba_copy_effective(source, dest);
}

static void
mac_biba_create_mbuf_from_ifnet(struct ifnet *ifnet, struct label *ifnetlabel,
    struct mbuf *m, struct label *mbuflabel)
{
	struct mac_biba *source, *dest;

	source = SLOT(ifnetlabel);
	dest = SLOT(mbuflabel);

	mac_biba_copy_effective(source, dest);
}

static void
mac_biba_create_mbuf_multicast_encap(struct mbuf *oldmbuf,
    struct label *oldmbuflabel, struct ifnet *ifnet, struct label *ifnetlabel,
    struct mbuf *newmbuf, struct label *newmbuflabel)
{
	struct mac_biba *source, *dest;

	source = SLOT(oldmbuflabel);
	dest = SLOT(newmbuflabel);

	mac_biba_copy_effective(source, dest);
}

static void
mac_biba_create_mbuf_netlayer(struct mbuf *oldmbuf, struct label *oldmbuflabel,
    struct mbuf *newmbuf, struct label *newmbuflabel)
{
	struct mac_biba *source, *dest;

	source = SLOT(oldmbuflabel);
	dest = SLOT(newmbuflabel);

	mac_biba_copy_effective(source, dest);
}

static int
mac_biba_fragment_match(struct mbuf *fragment, struct label *fragmentlabel,
    struct ipq *ipq, struct label *ipqlabel)
{
	struct mac_biba *a, *b;

	a = SLOT(ipqlabel);
	b = SLOT(fragmentlabel);

	return (mac_biba_equal_effective(a, b));
}

static void
mac_biba_relabel_ifnet(struct ucred *cred, struct ifnet *ifnet,
    struct label *ifnetlabel, struct label *newlabel)
{
	struct mac_biba *source, *dest;

	source = SLOT(newlabel);
	dest = SLOT(ifnetlabel);

	mac_biba_copy(source, dest);
}

static void
mac_biba_update_ipq(struct mbuf *fragment, struct label *fragmentlabel,
    struct ipq *ipq, struct label *ipqlabel)
{

	/* NOOP: we only accept matching labels, so no need to update */
}

static void
mac_biba_inpcb_sosetlabel(struct socket *so, struct label *solabel,
    struct inpcb *inp, struct label *inplabel)
{
	struct mac_biba *source, *dest;

	source = SLOT(solabel);
	dest = SLOT(inplabel);

	mac_biba_copy(source, dest);
}

static void
mac_biba_create_mbuf_from_firewall(struct mbuf *m, struct label *label)
{
	struct mac_biba *dest;

	dest = SLOT(label);

	/* XXX: where is the label for the firewall really comming from? */
	mac_biba_set_effective(dest, MAC_BIBA_TYPE_EQUAL, 0, NULL);
}

/*
 * Labeling event operations: processes.
 */
static void
mac_biba_create_proc0(struct ucred *cred)
{
	struct mac_biba *dest;

	dest = SLOT(cred->cr_label);

	mac_biba_set_effective(dest, MAC_BIBA_TYPE_EQUAL, 0, NULL);
	mac_biba_set_range(dest, MAC_BIBA_TYPE_LOW, 0, NULL,
	    MAC_BIBA_TYPE_HIGH, 0, NULL);
}

static void
mac_biba_create_proc1(struct ucred *cred)
{
	struct mac_biba *dest;

	dest = SLOT(cred->cr_label);

	mac_biba_set_effective(dest, MAC_BIBA_TYPE_HIGH, 0, NULL);
	mac_biba_set_range(dest, MAC_BIBA_TYPE_LOW, 0, NULL,
	    MAC_BIBA_TYPE_HIGH, 0, NULL);
}

static void
mac_biba_relabel_cred(struct ucred *cred, struct label *newlabel)
{
	struct mac_biba *source, *dest;

	source = SLOT(newlabel);
	dest = SLOT(cred->cr_label);

	mac_biba_copy(source, dest);
}

/*
 * Label cleanup/flush operations
 */
static void
mac_biba_cleanup_sysv_msgmsg(struct label *msglabel)
{

	bzero(SLOT(msglabel), sizeof(struct mac_biba));
}

static void
mac_biba_cleanup_sysv_msgqueue(struct label *msqlabel)
{

	bzero(SLOT(msqlabel), sizeof(struct mac_biba));
}

static void
mac_biba_cleanup_sysv_sem(struct label *semalabel)
{

	bzero(SLOT(semalabel), sizeof(struct mac_biba));
}

static void
mac_biba_cleanup_sysv_shm(struct label *shmlabel)
{
	bzero(SLOT(shmlabel), sizeof(struct mac_biba));
}

/*
 * Access control checks.
 */
static int
mac_biba_check_bpfdesc_receive(struct bpf_d *bpf_d, struct label *bpflabel,
    struct ifnet *ifnet, struct label *ifnetlabel)
{
	struct mac_biba *a, *b;

	if (!mac_biba_enabled)
		return (0);

	a = SLOT(bpflabel);
	b = SLOT(ifnetlabel);

	if (mac_biba_equal_effective(a, b))
		return (0);
	return (EACCES);
}

static int
mac_biba_check_cred_relabel(struct ucred *cred, struct label *newlabel)
{
	struct mac_biba *subj, *new;
	int error;

	subj = SLOT(cred->cr_label);
	new = SLOT(newlabel);

	/*
	 * If there is a Biba label update for the credential, it may
	 * be an update of the effective, range, or both.
	 */
	error = biba_atmostflags(new, MAC_BIBA_FLAGS_BOTH);
	if (error)
		return (error);

	/*
	 * If the Biba label is to be changed, authorize as appropriate.
	 */
	if (new->mb_flags & MAC_BIBA_FLAGS_BOTH) {
		/*
		 * If the change request modifies both the Biba label
		 * effective and range, check that the new effective will be
		 * in the new range.
		 */
		if ((new->mb_flags & MAC_BIBA_FLAGS_BOTH) ==
		    MAC_BIBA_FLAGS_BOTH &&
		    !mac_biba_effective_in_range(new, new))
			return (EINVAL);

		/*
		 * To change the Biba effective label on a credential, the
		 * new effective label must be in the current range.
		 */
		if (new->mb_flags & MAC_BIBA_FLAG_EFFECTIVE &&
		    !mac_biba_effective_in_range(new, subj))
			return (EPERM);

		/*
		 * To change the Biba range on a credential, the new
		 * range label must be in the current range.
		 */
		if (new->mb_flags & MAC_BIBA_FLAG_RANGE &&
		    !mac_biba_range_in_range(new, subj))
			return (EPERM);

		/*
		 * To have EQUAL in any component of the new credential
		 * Biba label, the subject must already have EQUAL in
		 * their label.
		 */
		if (mac_biba_contains_equal(new)) {
			error = mac_biba_subject_privileged(subj);
			if (error)
				return (error);
		}
	}

	return (0);
}

static int
mac_biba_check_cred_visible(struct ucred *u1, struct ucred *u2)
{
	struct mac_biba *subj, *obj;

	if (!mac_biba_enabled)
		return (0);

	subj = SLOT(u1->cr_label);
	obj = SLOT(u2->cr_label);

	/* XXX: range */
	if (!mac_biba_dominate_effective(obj, subj))
		return (ESRCH);

	return (0);
}

static int
mac_biba_check_ifnet_relabel(struct ucred *cred, struct ifnet *ifnet,
    struct label *ifnetlabel, struct label *newlabel)
{
	struct mac_biba *subj, *new;
	int error;

	subj = SLOT(cred->cr_label);
	new = SLOT(newlabel);

	/*
	 * If there is a Biba label update for the interface, it may
	 * be an update of the effective, range, or both.
	 */
	error = biba_atmostflags(new, MAC_BIBA_FLAGS_BOTH);
	if (error)
		return (error);

	/*
	 * Relabling network interfaces requires Biba privilege.
	 */
	error = mac_biba_subject_privileged(subj);
	if (error)
		return (error);

	return (0);
}

static int
mac_biba_check_ifnet_transmit(struct ifnet *ifnet, struct label *ifnetlabel,
    struct mbuf *m, struct label *mbuflabel)
{
	struct mac_biba *p, *i;

	if (!mac_biba_enabled)
		return (0);

	p = SLOT(mbuflabel);
	i = SLOT(ifnetlabel);

	return (mac_biba_effective_in_range(p, i) ? 0 : EACCES);
}

static int
mac_biba_check_inpcb_deliver(struct inpcb *inp, struct label *inplabel,
    struct mbuf *m, struct label *mlabel)
{
	struct mac_biba *p, *i;

	if (!mac_biba_enabled)
		return (0);

	p = SLOT(mlabel);
	i = SLOT(inplabel);

	return (mac_biba_equal_effective(p, i) ? 0 : EACCES);
}

static int
mac_biba_check_sysv_msgrcv(struct ucred *cred, struct msg *msgptr,
    struct label *msglabel)
{
	struct mac_biba *subj, *obj;

	if (!mac_biba_enabled)
		return (0);

	subj = SLOT(cred->cr_label);
	obj = SLOT(msglabel);

	if (!mac_biba_dominate_effective(obj, subj))
		return (EACCES);

	return (0);
}

static int
mac_biba_check_sysv_msgrmid(struct ucred *cred, struct msg *msgptr,
    struct label *msglabel)
{
	struct mac_biba *subj, *obj;

	if (!mac_biba_enabled)
		return (0);

	subj = SLOT(cred->cr_label);
	obj = SLOT(msglabel);

	if (!mac_biba_dominate_effective(subj, obj))
		return (EACCES);

	return (0);
}

static int
mac_biba_check_sysv_msqget(struct ucred *cred, struct msqid_kernel *msqkptr,
    struct label *msqklabel)
{
	struct mac_biba *subj, *obj;

	if (!mac_biba_enabled)
		return (0);

	subj = SLOT(cred->cr_label);
	obj = SLOT(msqklabel);

	if (!mac_biba_dominate_effective(obj, subj))
		return (EACCES);

	return (0);
}

static int
mac_biba_check_sysv_msqsnd(struct ucred *cred, struct msqid_kernel *msqkptr,
    struct label *msqklabel)
{
	struct mac_biba *subj, *obj;

	if (!mac_biba_enabled)
		return (0);

	subj = SLOT(cred->cr_label);
	obj = SLOT(msqklabel);

	if (!mac_biba_dominate_effective(subj, obj))
		return (EACCES);

	return (0);
}

static int
mac_biba_check_sysv_msqrcv(struct ucred *cred, struct msqid_kernel *msqkptr,
    struct label *msqklabel)
{
	struct mac_biba *subj, *obj;

	if (!mac_biba_enabled)
		return (0);

	subj = SLOT(cred->cr_label);
	obj = SLOT(msqklabel);

	if (!mac_biba_dominate_effective(obj, subj))
		return (EACCES);

	return (0);
}


static int
mac_biba_check_sysv_msqctl(struct ucred *cred, struct msqid_kernel *msqkptr,
    struct label *msqklabel, int cmd)
{
	struct mac_biba *subj, *obj;

	if (!mac_biba_enabled)
		return (0);

	subj = SLOT(cred->cr_label);
	obj = SLOT(msqklabel);

	switch(cmd) {
	case IPC_RMID:
	case IPC_SET:
		if (!mac_biba_dominate_effective(subj, obj))
			return (EACCES);
		break;

	case IPC_STAT:
		if (!mac_biba_dominate_effective(obj, subj))
			return (EACCES);
		break;

	default:
		return (EACCES);
	}

	return (0);
}

static int
mac_biba_check_sysv_semctl(struct ucred *cred, struct semid_kernel *semakptr,
    struct label *semaklabel, int cmd)
{
	struct mac_biba *subj, *obj;

	if (!mac_biba_enabled)
		return (0);

	subj = SLOT(cred->cr_label);
	obj = SLOT(semaklabel);

	switch(cmd) {
	case IPC_RMID:
	case IPC_SET:
	case SETVAL:
	case SETALL:
		if (!mac_biba_dominate_effective(subj, obj))
			return (EACCES);
		break;

	case IPC_STAT:
	case GETVAL:
	case GETPID:
	case GETNCNT:
	case GETZCNT:
	case GETALL:
		if (!mac_biba_dominate_effective(obj, subj))
			return (EACCES);
		break;

	default:
		return (EACCES);
	}

	return (0);
}


static int
mac_biba_check_sysv_semget(struct ucred *cred, struct semid_kernel *semakptr,
    struct label *semaklabel)
{
	struct mac_biba *subj, *obj;

	if (!mac_biba_enabled)
		return (0);

	subj = SLOT(cred->cr_label);
	obj = SLOT(semaklabel);

	if (!mac_biba_dominate_effective(obj, subj))
		return (EACCES);

	return (0);
}


static int
mac_biba_check_sysv_semop(struct ucred *cred, struct semid_kernel *semakptr,
    struct label *semaklabel, size_t accesstype)
{
	struct mac_biba *subj, *obj;

	if (!mac_biba_enabled)
		return (0);

	subj = SLOT(cred->cr_label);
	obj = SLOT(semaklabel);

	if (accesstype & SEM_R)
		if (!mac_biba_dominate_effective(obj, subj))
			return (EACCES);

	if (accesstype & SEM_A)
		if (!mac_biba_dominate_effective(subj, obj))
			return (EACCES);

	return (0);
}

static int
mac_biba_check_sysv_shmat(struct ucred *cred, struct shmid_kernel *shmsegptr,
    struct label *shmseglabel, int shmflg)
{
	struct mac_biba *subj, *obj;

	if (!mac_biba_enabled)
		return (0);

	subj = SLOT(cred->cr_label);
	obj = SLOT(shmseglabel);

	if (!mac_biba_dominate_effective(obj, subj))
		return (EACCES);
	if ((shmflg & SHM_RDONLY) == 0) {
		if (!mac_biba_dominate_effective(subj, obj))
			return (EACCES);
	}

	return (0);
}

static int
mac_biba_check_sysv_shmctl(struct ucred *cred, struct shmid_kernel *shmsegptr,
    struct label *shmseglabel, int cmd)
{
	struct mac_biba *subj, *obj;

	if (!mac_biba_enabled)
		return (0);

	subj = SLOT(cred->cr_label);
	obj = SLOT(shmseglabel);

	switch(cmd) {
	case IPC_RMID:
	case IPC_SET:
		if (!mac_biba_dominate_effective(subj, obj))
			return (EACCES);
		break;

	case IPC_STAT:
	case SHM_STAT:
		if (!mac_biba_dominate_effective(obj, subj))
			return (EACCES);
		break;

	default:
		return (EACCES);
	}

	return (0);
}

static int
mac_biba_check_sysv_shmget(struct ucred *cred, struct shmid_kernel *shmsegptr,
    struct label *shmseglabel, int shmflg)
{
	struct mac_biba *subj, *obj;

	if (!mac_biba_enabled)
		return (0);

	subj = SLOT(cred->cr_label);
	obj = SLOT(shmseglabel);

	if (!mac_biba_dominate_effective(obj, subj))
		return (EACCES);

	return (0);
}

static int
mac_biba_check_kld_load(struct ucred *cred, struct vnode *vp,
    struct label *label)
{
	struct mac_biba *subj, *obj;
	int error;

	if (!mac_biba_enabled)
		return (0);

	subj = SLOT(cred->cr_label);

	error = mac_biba_subject_privileged(subj);
	if (error)
		return (error);

	obj = SLOT(label);
	if (!mac_biba_high_effective(obj))
		return (EACCES);

	return (0);
}


static int
mac_biba_check_kld_unload(struct ucred *cred)
{
	struct mac_biba *subj;

	if (!mac_biba_enabled)
		return (0);

	subj = SLOT(cred->cr_label);

	return (mac_biba_subject_privileged(subj));
}

static int
mac_biba_check_mount_stat(struct ucred *cred, struct mount *mp,
    struct label *mntlabel)
{
	struct mac_biba *subj, *obj;

	if (!mac_biba_enabled)
		return (0);

	subj = SLOT(cred->cr_label);
	obj = SLOT(mntlabel);

	if (!mac_biba_dominate_effective(obj, subj))
		return (EACCES);

	return (0);
}

static int
mac_biba_check_pipe_ioctl(struct ucred *cred, struct pipepair *pp,
    struct label *pipelabel, unsigned long cmd, void /* caddr_t */ *data)
{

	if(!mac_biba_enabled)
		return (0);

	/* XXX: This will be implemented soon... */

	return (0);
}

static int
mac_biba_check_pipe_poll(struct ucred *cred, struct pipepair *pp,
    struct label *pipelabel)
{
	struct mac_biba *subj, *obj;

	if (!mac_biba_enabled)
		return (0);

	subj = SLOT(cred->cr_label);
	obj = SLOT((pipelabel));

	if (!mac_biba_dominate_effective(obj, subj))
		return (EACCES);

	return (0);
}

static int
mac_biba_check_pipe_read(struct ucred *cred, struct pipepair *pp,
    struct label *pipelabel)
{
	struct mac_biba *subj, *obj;

	if (!mac_biba_enabled)
		return (0);

	subj = SLOT(cred->cr_label);
	obj = SLOT((pipelabel));

	if (!mac_biba_dominate_effective(obj, subj))
		return (EACCES);

	return (0);
}

static int
mac_biba_check_pipe_relabel(struct ucred *cred, struct pipepair *pp,
    struct label *pipelabel, struct label *newlabel)
{
	struct mac_biba *subj, *obj, *new;
	int error;

	new = SLOT(newlabel);
	subj = SLOT(cred->cr_label);
	obj = SLOT(pipelabel);

	/*
	 * If there is a Biba label update for a pipe, it must be a
	 * effective update.
	 */
	error = biba_atmostflags(new, MAC_BIBA_FLAG_EFFECTIVE);
	if (error)
		return (error);

	/*
	 * To perform a relabel of a pipe (Biba label or not), Biba must
	 * authorize the relabel.
	 */
	if (!mac_biba_effective_in_range(obj, subj))
		return (EPERM);

	/*
	 * If the Biba label is to be changed, authorize as appropriate.
	 */
	if (new->mb_flags & MAC_BIBA_FLAG_EFFECTIVE) {
		/*
		 * To change the Biba label on a pipe, the new pipe label
		 * must be in the subject range.
		 */
		if (!mac_biba_effective_in_range(new, subj))
			return (EPERM);

		/*
		 * To change the Biba label on a pipe to be EQUAL, the
		 * subject must have appropriate privilege.
		 */
		if (mac_biba_contains_equal(new)) {
			error = mac_biba_subject_privileged(subj);
			if (error)
				return (error);
		}
	}

	return (0);
}

static int
mac_biba_check_pipe_stat(struct ucred *cred, struct pipepair *pp,
    struct label *pipelabel)
{
	struct mac_biba *subj, *obj;

	if (!mac_biba_enabled)
		return (0);

	subj = SLOT(cred->cr_label);
	obj = SLOT((pipelabel));

	if (!mac_biba_dominate_effective(obj, subj))
		return (EACCES);

	return (0);
}

static int
mac_biba_check_pipe_write(struct ucred *cred, struct pipepair *pp,
    struct label *pipelabel)
{
	struct mac_biba *subj, *obj;

	if (!mac_biba_enabled)
		return (0);

	subj = SLOT(cred->cr_label);
	obj = SLOT((pipelabel));

	if (!mac_biba_dominate_effective(subj, obj))
		return (EACCES);

	return (0);
}

static int
mac_biba_check_posix_sem_write(struct ucred *cred, struct ksem *ksemptr,
    struct label *ks_label)
{
	struct mac_biba *subj, *obj;

	if (!mac_biba_enabled)
		return (0);

	subj = SLOT(cred->cr_label);
	obj = SLOT(ks_label);

	if (!mac_biba_dominate_effective(subj, obj))
		return (EACCES);

	return (0);
}

static int
mac_biba_check_posix_sem_rdonly(struct ucred *cred, struct ksem *ksemptr,
    struct label *ks_label)
{
	struct mac_biba *subj, *obj;

	if (!mac_biba_enabled)
		return (0);

	subj = SLOT(cred->cr_label);
	obj = SLOT(ks_label);

	if (!mac_biba_dominate_effective(obj, subj))
		return (EACCES);

	return (0);
}

static int
mac_biba_check_proc_debug(struct ucred *cred, struct proc *proc)
{
	struct mac_biba *subj, *obj;

	if (!mac_biba_enabled)
		return (0);

	subj = SLOT(cred->cr_label);
	obj = SLOT(proc->p_ucred->cr_label);

	/* XXX: range checks */
	if (!mac_biba_dominate_effective(obj, subj))
		return (ESRCH);
	if (!mac_biba_dominate_effective(subj, obj))
		return (EACCES);

	return (0);
}

static int
mac_biba_check_proc_sched(struct ucred *cred, struct proc *proc)
{
	struct mac_biba *subj, *obj;

	if (!mac_biba_enabled)
		return (0);

	subj = SLOT(cred->cr_label);
	obj = SLOT(proc->p_ucred->cr_label);

	/* XXX: range checks */
	if (!mac_biba_dominate_effective(obj, subj))
		return (ESRCH);
	if (!mac_biba_dominate_effective(subj, obj))
		return (EACCES);

	return (0);
}

static int
mac_biba_check_proc_signal(struct ucred *cred, struct proc *proc, int signum)
{
	struct mac_biba *subj, *obj;

	if (!mac_biba_enabled)
		return (0);

	subj = SLOT(cred->cr_label);
	obj = SLOT(proc->p_ucred->cr_label);

	/* XXX: range checks */
	if (!mac_biba_dominate_effective(obj, subj))
		return (ESRCH);
	if (!mac_biba_dominate_effective(subj, obj))
		return (EACCES);

	return (0);
}

static int
mac_biba_check_socket_deliver(struct socket *so, struct label *socketlabel,
    struct mbuf *m, struct label *mbuflabel)
{
	struct mac_biba *p, *s;

	if (!mac_biba_enabled)
		return (0);

	p = SLOT(mbuflabel);
	s = SLOT(socketlabel);

	return (mac_biba_equal_effective(p, s) ? 0 : EACCES);
}

static int
mac_biba_check_socket_relabel(struct ucred *cred, struct socket *so,
    struct label *socketlabel, struct label *newlabel)
{
	struct mac_biba *subj, *obj, *new;
	int error;

	new = SLOT(newlabel);
	subj = SLOT(cred->cr_label);
	obj = SLOT(socketlabel);

	/*
	 * If there is a Biba label update for the socket, it may be
	 * an update of effective.
	 */
	error = biba_atmostflags(new, MAC_BIBA_FLAG_EFFECTIVE);
	if (error)
		return (error);

	/*
	 * To relabel a socket, the old socket effective must be in the subject
	 * range.
	 */
	if (!mac_biba_effective_in_range(obj, subj))
		return (EPERM);

	/*
	 * If the Biba label is to be changed, authorize as appropriate.
	 */
	if (new->mb_flags & MAC_BIBA_FLAG_EFFECTIVE) {
		/*
		 * To relabel a socket, the new socket effective must be in
		 * the subject range.
		 */
		if (!mac_biba_effective_in_range(new, subj))
			return (EPERM);

		/*
		 * To change the Biba label on the socket to contain EQUAL,
		 * the subject must have appropriate privilege.
		 */
		if (mac_biba_contains_equal(new)) {
			error = mac_biba_subject_privileged(subj);
			if (error)
				return (error);
		}
	}

	return (0);
}

static int
mac_biba_check_socket_visible(struct ucred *cred, struct socket *socket,
    struct label *socketlabel)
{
	struct mac_biba *subj, *obj;

	if (!mac_biba_enabled)
		return (0);

	subj = SLOT(cred->cr_label);
	obj = SLOT(socketlabel);

	if (!mac_biba_dominate_effective(obj, subj))
		return (ENOENT);

	return (0);
}

static int
mac_biba_check_sysarch_ioperm(struct ucred *cred)
{
	struct mac_biba *subj;
	int error;

	if (!mac_biba_enabled)
		return (0);

	subj = SLOT(cred->cr_label);

	error = mac_biba_subject_privileged(subj);
	if (error)
		return (error);

	return (0);
}

static int
mac_biba_check_system_acct(struct ucred *cred, struct vnode *vp,
    struct label *label)
{
	struct mac_biba *subj, *obj;
	int error;

	if (!mac_biba_enabled)
		return (0);

	subj = SLOT(cred->cr_label);

	error = mac_biba_subject_privileged(subj);
	if (error)
		return (error);

	if (label == NULL)
		return (0);

	obj = SLOT(label);
	if (!mac_biba_high_effective(obj))
		return (EACCES);

	return (0);
}

static int
mac_biba_check_system_settime(struct ucred *cred)
{
	struct mac_biba *subj;
	int error;

	if (!mac_biba_enabled)
		return (0);

	subj = SLOT(cred->cr_label);

	error = mac_biba_subject_privileged(subj);
	if (error)
		return (error);

	return (0);
}

static int
mac_biba_check_system_swapon(struct ucred *cred, struct vnode *vp,
    struct label *label)
{
	struct mac_biba *subj, *obj;
	int error;

	if (!mac_biba_enabled)
		return (0);

	subj = SLOT(cred->cr_label);
	obj = SLOT(label);

	error = mac_biba_subject_privileged(subj);
	if (error)
		return (error);

	if (!mac_biba_high_effective(obj))
		return (EACCES);

	return (0);
}

static int
mac_biba_check_system_swapoff(struct ucred *cred, struct vnode *vp,
    struct label *label)
{
	struct mac_biba *subj;
	int error;

	if (!mac_biba_enabled)
		return (0);

	subj = SLOT(cred->cr_label);

	error = mac_biba_subject_privileged(subj);
	if (error)
		return (error);

	return (0);
}

static int
mac_biba_check_system_sysctl(struct ucred *cred, struct sysctl_oid *oidp,
    void *arg1, int arg2, struct sysctl_req *req)
{
	struct mac_biba *subj;
	int error;

	if (!mac_biba_enabled)
		return (0);

	subj = SLOT(cred->cr_label);

	/*
	 * Treat sysctl variables without CTLFLAG_ANYBODY flag as
	 * biba/high, but also require privilege to change them.
	 */
	if (req->newptr != NULL && (oidp->oid_kind & CTLFLAG_ANYBODY) == 0) {
		if (!mac_biba_subject_dominate_high(subj))
			return (EACCES);

		error = mac_biba_subject_privileged(subj);
		if (error)
			return (error);
	}

	return (0);
}

static int
mac_biba_check_vnode_chdir(struct ucred *cred, struct vnode *dvp,
    struct label *dlabel)
{
	struct mac_biba *subj, *obj;

	if (!mac_biba_enabled)
		return (0);

	subj = SLOT(cred->cr_label);
	obj = SLOT(dlabel);

	if (!mac_biba_dominate_effective(obj, subj))
		return (EACCES);

	return (0);
}

static int
mac_biba_check_vnode_chroot(struct ucred *cred, struct vnode *dvp,
    struct label *dlabel)
{
	struct mac_biba *subj, *obj;

	if (!mac_biba_enabled)
		return (0);

	subj = SLOT(cred->cr_label);
	obj = SLOT(dlabel);

	if (!mac_biba_dominate_effective(obj, subj))
		return (EACCES);

	return (0);
}

static int
mac_biba_check_vnode_create(struct ucred *cred, struct vnode *dvp,
    struct label *dlabel, struct componentname *cnp, struct vattr *vap)
{
	struct mac_biba *subj, *obj;

	if (!mac_biba_enabled)
		return (0);

	subj = SLOT(cred->cr_label);
	obj = SLOT(dlabel);

	if (!mac_biba_dominate_effective(subj, obj))
		return (EACCES);

	return (0);
}

static int
mac_biba_check_vnode_delete(struct ucred *cred, struct vnode *dvp,
    struct label *dlabel, struct vnode *vp, struct label *label,
    struct componentname *cnp)
{
	struct mac_biba *subj, *obj;

	if (!mac_biba_enabled)
		return (0);

	subj = SLOT(cred->cr_label);
	obj = SLOT(dlabel);

	if (!mac_biba_dominate_effective(subj, obj))
		return (EACCES);

	obj = SLOT(label);

	if (!mac_biba_dominate_effective(subj, obj))
		return (EACCES);

	return (0);
}

static int
mac_biba_check_vnode_deleteacl(struct ucred *cred, struct vnode *vp,
    struct label *label, acl_type_t type)
{
	struct mac_biba *subj, *obj;

	if (!mac_biba_enabled)
		return (0);

	subj = SLOT(cred->cr_label);
	obj = SLOT(label);

	if (!mac_biba_dominate_effective(subj, obj))
		return (EACCES);

	return (0);
}

static int
mac_biba_check_vnode_deleteextattr(struct ucred *cred, struct vnode *vp,
    struct label *label, int attrnamespace, const char *name)
{
	struct mac_biba *subj, *obj;

	if (!mac_biba_enabled)
		return (0);

	subj = SLOT(cred->cr_label);
	obj = SLOT(label);

	if (!mac_biba_dominate_effective(subj, obj))
		return (EACCES);

	return (0);
}

static int
mac_biba_check_vnode_exec(struct ucred *cred, struct vnode *vp,
    struct label *label, struct image_params *imgp,
    struct label *execlabel)
{
	struct mac_biba *subj, *obj, *exec;
	int error;

	if (execlabel != NULL) {
		/*
		 * We currently don't permit labels to be changed at
		 * exec-time as part of Biba, so disallow non-NULL
		 * Biba label elements in the execlabel.
		 */
		exec = SLOT(execlabel);
		error = biba_atmostflags(exec, 0);
		if (error)
			return (error);
	}

	if (!mac_biba_enabled)
		return (0);

	subj = SLOT(cred->cr_label);
	obj = SLOT(label);

	if (!mac_biba_dominate_effective(obj, subj))
		return (EACCES);

	return (0);
}

static int
mac_biba_check_vnode_getacl(struct ucred *cred, struct vnode *vp,
    struct label *label, acl_type_t type)
{
	struct mac_biba *subj, *obj;

	if (!mac_biba_enabled)
		return (0);

	subj = SLOT(cred->cr_label);
	obj = SLOT(label);

	if (!mac_biba_dominate_effective(obj, subj))
		return (EACCES);

	return (0);
}

static int
mac_biba_check_vnode_getextattr(struct ucred *cred, struct vnode *vp,
    struct label *label, int attrnamespace, const char *name, struct uio *uio)
{
	struct mac_biba *subj, *obj;

	if (!mac_biba_enabled)
		return (0);

	subj = SLOT(cred->cr_label);
	obj = SLOT(label);

	if (!mac_biba_dominate_effective(obj, subj))
		return (EACCES);

	return (0);
}

static int
mac_biba_check_vnode_link(struct ucred *cred, struct vnode *dvp,
    struct label *dlabel, struct vnode *vp, struct label *label,
    struct componentname *cnp)
{
	struct mac_biba *subj, *obj;

	if (!mac_biba_enabled)
		return (0);

	subj = SLOT(cred->cr_label);
	obj = SLOT(dlabel);

	if (!mac_biba_dominate_effective(subj, obj))
		return (EACCES);

	obj = SLOT(label);

	if (!mac_biba_dominate_effective(subj, obj))
		return (EACCES);

	return (0);
}

static int
mac_biba_check_vnode_listextattr(struct ucred *cred, struct vnode *vp,
    struct label *label, int attrnamespace)
{
	struct mac_biba *subj, *obj;

	if (!mac_biba_enabled)
		return (0);

	subj = SLOT(cred->cr_label);
	obj = SLOT(label);

	if (!mac_biba_dominate_effective(obj, subj))
		return (EACCES);

	return (0);
}

static int
mac_biba_check_vnode_lookup(struct ucred *cred, struct vnode *dvp,
    struct label *dlabel, struct componentname *cnp)
{
	struct mac_biba *subj, *obj;

	if (!mac_biba_enabled)
		return (0);

	subj = SLOT(cred->cr_label);
	obj = SLOT(dlabel);

	if (!mac_biba_dominate_effective(obj, subj))
		return (EACCES);

	return (0);
}

static int
mac_biba_check_vnode_mmap(struct ucred *cred, struct vnode *vp,
    struct label *label, int prot, int flags)
{
	struct mac_biba *subj, *obj;

	/*
	 * Rely on the use of open()-time protections to handle
	 * non-revocation cases.
	 */
	if (!mac_biba_enabled || !revocation_enabled)
		return (0);

	subj = SLOT(cred->cr_label);
	obj = SLOT(label);

	if (prot & (VM_PROT_READ | VM_PROT_EXECUTE)) {
		if (!mac_biba_dominate_effective(obj, subj))
			return (EACCES);
	}
	if (((prot & VM_PROT_WRITE) != 0) && ((flags & MAP_SHARED) != 0)) {
		if (!mac_biba_dominate_effective(subj, obj))
			return (EACCES);
	}

	return (0);
}

static int
mac_biba_check_vnode_open(struct ucred *cred, struct vnode *vp,
    struct label *vnodelabel, int acc_mode)
{
	struct mac_biba *subj, *obj;

	if (!mac_biba_enabled)
		return (0);

	subj = SLOT(cred->cr_label);
	obj = SLOT(vnodelabel);

	/* XXX privilege override for admin? */
	if (acc_mode & (VREAD | VEXEC | VSTAT)) {
		if (!mac_biba_dominate_effective(obj, subj))
			return (EACCES);
	}
	if (acc_mode & (VWRITE | VAPPEND | VADMIN)) {
		if (!mac_biba_dominate_effective(subj, obj))
			return (EACCES);
	}

	return (0);
}

static int
mac_biba_check_vnode_poll(struct ucred *active_cred, struct ucred *file_cred,
    struct vnode *vp, struct label *label)
{
	struct mac_biba *subj, *obj;

	if (!mac_biba_enabled || !revocation_enabled)
		return (0);

	subj = SLOT(active_cred->cr_label);
	obj = SLOT(label);

	if (!mac_biba_dominate_effective(obj, subj))
		return (EACCES);

	return (0);
}

static int
mac_biba_check_vnode_read(struct ucred *active_cred, struct ucred *file_cred,
    struct vnode *vp, struct label *label)
{
	struct mac_biba *subj, *obj;

	if (!mac_biba_enabled || !revocation_enabled)
		return (0);

	subj = SLOT(active_cred->cr_label);
	obj = SLOT(label);

	if (!mac_biba_dominate_effective(obj, subj))
		return (EACCES);

	return (0);
}

static int
mac_biba_check_vnode_readdir(struct ucred *cred, struct vnode *dvp,
    struct label *dlabel)
{
	struct mac_biba *subj, *obj;

	if (!mac_biba_enabled)
		return (0);

	subj = SLOT(cred->cr_label);
	obj = SLOT(dlabel);

	if (!mac_biba_dominate_effective(obj, subj))
		return (EACCES);

	return (0);
}

static int
mac_biba_check_vnode_readlink(struct ucred *cred, struct vnode *vp,
    struct label *label)
{
	struct mac_biba *subj, *obj;

	if (!mac_biba_enabled)
		return (0);

	subj = SLOT(cred->cr_label);
	obj = SLOT(label);

	if (!mac_biba_dominate_effective(obj, subj))
		return (EACCES);

	return (0);
}

static int
mac_biba_check_vnode_relabel(struct ucred *cred, struct vnode *vp,
    struct label *vnodelabel, struct label *newlabel)
{
	struct mac_biba *old, *new, *subj;
	int error;

	old = SLOT(vnodelabel);
	new = SLOT(newlabel);
	subj = SLOT(cred->cr_label);

	/*
	 * If there is a Biba label update for the vnode, it must be a
	 * effective label.
	 */
	error = biba_atmostflags(new, MAC_BIBA_FLAG_EFFECTIVE);
	if (error)
		return (error);

	/*
	 * To perform a relabel of the vnode (Biba label or not), Biba must
	 * authorize the relabel.
	 */
	if (!mac_biba_effective_in_range(old, subj))
		return (EPERM);

	/*
	 * If the Biba label is to be changed, authorize as appropriate.
	 */
	if (new->mb_flags & MAC_BIBA_FLAG_EFFECTIVE) {
		/*
		 * To change the Biba label on a vnode, the new vnode label
		 * must be in the subject range.
		 */
		if (!mac_biba_effective_in_range(new, subj))
			return (EPERM);

		/*
		 * To change the Biba label on the vnode to be EQUAL,
		 * the subject must have appropriate privilege.
		 */
		if (mac_biba_contains_equal(new)) {
			error = mac_biba_subject_privileged(subj);
			if (error)
				return (error);
		}
	}

	return (0);
}

static int
mac_biba_check_vnode_rename_from(struct ucred *cred, struct vnode *dvp,
    struct label *dlabel, struct vnode *vp, struct label *label,
    struct componentname *cnp)
{
	struct mac_biba *subj, *obj;

	if (!mac_biba_enabled)
		return (0);

	subj = SLOT(cred->cr_label);
	obj = SLOT(dlabel);

	if (!mac_biba_dominate_effective(subj, obj))
		return (EACCES);

	obj = SLOT(label);

	if (!mac_biba_dominate_effective(subj, obj))
		return (EACCES);

	return (0);
}

static int
mac_biba_check_vnode_rename_to(struct ucred *cred, struct vnode *dvp,
    struct label *dlabel, struct vnode *vp, struct label *label, int samedir,
    struct componentname *cnp)
{
	struct mac_biba *subj, *obj;

	if (!mac_biba_enabled)
		return (0);

	subj = SLOT(cred->cr_label);
	obj = SLOT(dlabel);

	if (!mac_biba_dominate_effective(subj, obj))
		return (EACCES);

	if (vp != NULL) {
		obj = SLOT(label);

		if (!mac_biba_dominate_effective(subj, obj))
			return (EACCES);
	}

	return (0);
}

static int
mac_biba_check_vnode_revoke(struct ucred *cred, struct vnode *vp,
    struct label *label)
{
	struct mac_biba *subj, *obj;

	if (!mac_biba_enabled)
		return (0);

	subj = SLOT(cred->cr_label);
	obj = SLOT(label);

	if (!mac_biba_dominate_effective(subj, obj))
		return (EACCES);

	return (0);
}

static int
mac_biba_check_vnode_setacl(struct ucred *cred, struct vnode *vp,
    struct label *label, acl_type_t type, struct acl *acl)
{
	struct mac_biba *subj, *obj;

	if (!mac_biba_enabled)
		return (0);

	subj = SLOT(cred->cr_label);
	obj = SLOT(label);

	if (!mac_biba_dominate_effective(subj, obj))
		return (EACCES);

	return (0);
}

static int
mac_biba_check_vnode_setextattr(struct ucred *cred, struct vnode *vp,
    struct label *vnodelabel, int attrnamespace, const char *name,
    struct uio *uio)
{
	struct mac_biba *subj, *obj;

	if (!mac_biba_enabled)
		return (0);

	subj = SLOT(cred->cr_label);
	obj = SLOT(vnodelabel);

	if (!mac_biba_dominate_effective(subj, obj))
		return (EACCES);

	/* XXX: protect the MAC EA in a special way? */

	return (0);
}

static int
mac_biba_check_vnode_setflags(struct ucred *cred, struct vnode *vp,
    struct label *vnodelabel, u_long flags)
{
	struct mac_biba *subj, *obj;

	if (!mac_biba_enabled)
		return (0);

	subj = SLOT(cred->cr_label);
	obj = SLOT(vnodelabel);

	if (!mac_biba_dominate_effective(subj, obj))
		return (EACCES);

	return (0);
}

static int
mac_biba_check_vnode_setmode(struct ucred *cred, struct vnode *vp,
    struct label *vnodelabel, mode_t mode)
{
	struct mac_biba *subj, *obj;

	if (!mac_biba_enabled)
		return (0);

	subj = SLOT(cred->cr_label);
	obj = SLOT(vnodelabel);

	if (!mac_biba_dominate_effective(subj, obj))
		return (EACCES);

	return (0);
}

static int
mac_biba_check_vnode_setowner(struct ucred *cred, struct vnode *vp,
    struct label *vnodelabel, uid_t uid, gid_t gid)
{
	struct mac_biba *subj, *obj;

	if (!mac_biba_enabled)
		return (0);

	subj = SLOT(cred->cr_label);
	obj = SLOT(vnodelabel);

	if (!mac_biba_dominate_effective(subj, obj))
		return (EACCES);

	return (0);
}

static int
mac_biba_check_vnode_setutimes(struct ucred *cred, struct vnode *vp,
    struct label *vnodelabel, struct timespec atime, struct timespec mtime)
{
	struct mac_biba *subj, *obj;

	if (!mac_biba_enabled)
		return (0);

	subj = SLOT(cred->cr_label);
	obj = SLOT(vnodelabel);

	if (!mac_biba_dominate_effective(subj, obj))
		return (EACCES);

	return (0);
}

static int
mac_biba_check_vnode_stat(struct ucred *active_cred, struct ucred *file_cred,
    struct vnode *vp, struct label *vnodelabel)
{
	struct mac_biba *subj, *obj;

	if (!mac_biba_enabled)
		return (0);

	subj = SLOT(active_cred->cr_label);
	obj = SLOT(vnodelabel);

	if (!mac_biba_dominate_effective(obj, subj))
		return (EACCES);

	return (0);
}

static int
mac_biba_check_vnode_write(struct ucred *active_cred,
    struct ucred *file_cred, struct vnode *vp, struct label *label)
{
	struct mac_biba *subj, *obj;

	if (!mac_biba_enabled || !revocation_enabled)
		return (0);

	subj = SLOT(active_cred->cr_label);
	obj = SLOT(label);

	if (!mac_biba_dominate_effective(subj, obj))
		return (EACCES);

	return (0);
}

static void
mac_biba_associate_nfsd_label(struct ucred *cred)
{
	struct mac_biba *label;

	label = SLOT(cred->cr_label);
	mac_biba_set_effective(label, MAC_BIBA_TYPE_LOW, 0, NULL);
	mac_biba_set_range(label, MAC_BIBA_TYPE_LOW, 0, NULL,
	    MAC_BIBA_TYPE_HIGH, 0, NULL);
}

static void
mac_biba_init_syncache_from_inpcb(struct label *label, struct inpcb *inp)
{
	struct mac_biba *source, *dest;

	source = SLOT(inp->inp_label);
	dest = SLOT(label);
	mac_biba_copy_effective(source, dest);
}

static void
mac_biba_create_mbuf_from_syncache(struct label *sc_label, struct mbuf *m,
    struct label *mbuf_label)
{
	struct mac_biba *source, *dest;

	source = SLOT(sc_label);
	dest = SLOT(mbuf_label);
	mac_biba_copy_effective(source, dest);
}

static struct mac_policy_ops mac_biba_ops =
{
	.mpo_init = mac_biba_init,
	.mpo_init_bpfdesc_label = mac_biba_init_label,
	.mpo_init_cred_label = mac_biba_init_label,
	.mpo_init_devfsdirent_label = mac_biba_init_label,
	.mpo_init_ifnet_label = mac_biba_init_label,
	.mpo_init_inpcb_label = mac_biba_init_label_waitcheck,
	.mpo_init_syncache_label = mac_biba_init_label_waitcheck,
	.mpo_init_sysv_msgmsg_label = mac_biba_init_label,
	.mpo_init_sysv_msgqueue_label = mac_biba_init_label,
	.mpo_init_sysv_sem_label = mac_biba_init_label,
	.mpo_init_sysv_shm_label = mac_biba_init_label,
	.mpo_init_ipq_label = mac_biba_init_label_waitcheck,
	.mpo_init_mbuf_label = mac_biba_init_label_waitcheck,
	.mpo_init_mount_label = mac_biba_init_label,
	.mpo_init_mount_fs_label = mac_biba_init_label,
	.mpo_init_pipe_label = mac_biba_init_label,
	.mpo_init_posix_sem_label = mac_biba_init_label,
	.mpo_init_socket_label = mac_biba_init_label_waitcheck,
	.mpo_init_socket_peer_label = mac_biba_init_label_waitcheck,
	.mpo_init_syncache_from_inpcb = mac_biba_init_syncache_from_inpcb,
	.mpo_init_vnode_label = mac_biba_init_label,
	.mpo_destroy_bpfdesc_label = mac_biba_destroy_label,
	.mpo_destroy_cred_label = mac_biba_destroy_label,
	.mpo_destroy_devfsdirent_label = mac_biba_destroy_label,
	.mpo_destroy_ifnet_label = mac_biba_destroy_label,
	.mpo_destroy_inpcb_label = mac_biba_destroy_label,
	.mpo_destroy_syncache_label = mac_biba_destroy_label,
	.mpo_destroy_sysv_msgmsg_label = mac_biba_destroy_label,
	.mpo_destroy_sysv_msgqueue_label = mac_biba_destroy_label,
	.mpo_destroy_sysv_sem_label = mac_biba_destroy_label,
	.mpo_destroy_sysv_shm_label = mac_biba_destroy_label,
	.mpo_destroy_ipq_label = mac_biba_destroy_label,
	.mpo_destroy_mbuf_label = mac_biba_destroy_label,
	.mpo_destroy_mount_label = mac_biba_destroy_label,
	.mpo_destroy_mount_fs_label = mac_biba_destroy_label,
	.mpo_destroy_pipe_label = mac_biba_destroy_label,
	.mpo_destroy_posix_sem_label = mac_biba_destroy_label,
	.mpo_destroy_socket_label = mac_biba_destroy_label,
	.mpo_destroy_socket_peer_label = mac_biba_destroy_label,
	.mpo_destroy_vnode_label = mac_biba_destroy_label,
	.mpo_copy_cred_label = mac_biba_copy_label,
	.mpo_copy_ifnet_label = mac_biba_copy_label,
	.mpo_copy_mbuf_label = mac_biba_copy_label,
	.mpo_copy_pipe_label = mac_biba_copy_label,
	.mpo_copy_socket_label = mac_biba_copy_label,
	.mpo_copy_vnode_label = mac_biba_copy_label,
	.mpo_externalize_cred_label = mac_biba_externalize_label,
	.mpo_externalize_ifnet_label = mac_biba_externalize_label,
	.mpo_externalize_pipe_label = mac_biba_externalize_label,
	.mpo_externalize_socket_label = mac_biba_externalize_label,
	.mpo_externalize_socket_peer_label = mac_biba_externalize_label,
	.mpo_externalize_vnode_label = mac_biba_externalize_label,
	.mpo_internalize_cred_label = mac_biba_internalize_label,
	.mpo_internalize_ifnet_label = mac_biba_internalize_label,
	.mpo_internalize_pipe_label = mac_biba_internalize_label,
	.mpo_internalize_socket_label = mac_biba_internalize_label,
	.mpo_internalize_vnode_label = mac_biba_internalize_label,
	.mpo_create_devfs_device = mac_biba_create_devfs_device,
	.mpo_create_devfs_directory = mac_biba_create_devfs_directory,
	.mpo_create_devfs_symlink = mac_biba_create_devfs_symlink,
	.mpo_create_mount = mac_biba_create_mount,
	.mpo_relabel_vnode = mac_biba_relabel_vnode,
	.mpo_update_devfsdirent = mac_biba_update_devfsdirent,
	.mpo_associate_vnode_devfs = mac_biba_associate_vnode_devfs,
	.mpo_associate_vnode_extattr = mac_biba_associate_vnode_extattr,
	.mpo_associate_vnode_singlelabel = mac_biba_associate_vnode_singlelabel,
	.mpo_create_vnode_extattr = mac_biba_create_vnode_extattr,
	.mpo_setlabel_vnode_extattr = mac_biba_setlabel_vnode_extattr,
	.mpo_create_mbuf_from_socket = mac_biba_create_mbuf_from_socket,
	.mpo_create_mbuf_from_syncache = mac_biba_create_mbuf_from_syncache,
	.mpo_create_pipe = mac_biba_create_pipe,
	.mpo_create_posix_sem = mac_biba_create_posix_sem,
	.mpo_create_socket = mac_biba_create_socket,
	.mpo_create_socket_from_socket = mac_biba_create_socket_from_socket,
	.mpo_relabel_pipe = mac_biba_relabel_pipe,
	.mpo_relabel_socket = mac_biba_relabel_socket,
	.mpo_set_socket_peer_from_mbuf = mac_biba_set_socket_peer_from_mbuf,
	.mpo_set_socket_peer_from_socket = mac_biba_set_socket_peer_from_socket,
	.mpo_create_bpfdesc = mac_biba_create_bpfdesc,
	.mpo_create_datagram_from_ipq = mac_biba_create_datagram_from_ipq,
	.mpo_create_fragment = mac_biba_create_fragment,
	.mpo_create_ifnet = mac_biba_create_ifnet,
	.mpo_create_inpcb_from_socket = mac_biba_create_inpcb_from_socket,
	.mpo_create_sysv_msgmsg = mac_biba_create_sysv_msgmsg,
	.mpo_create_sysv_msgqueue = mac_biba_create_sysv_msgqueue,
	.mpo_create_sysv_sem = mac_biba_create_sysv_sem,
	.mpo_create_sysv_shm = mac_biba_create_sysv_shm,
	.mpo_create_ipq = mac_biba_create_ipq,
	.mpo_create_mbuf_from_inpcb = mac_biba_create_mbuf_from_inpcb,
	.mpo_create_mbuf_linklayer = mac_biba_create_mbuf_linklayer,
	.mpo_create_mbuf_from_bpfdesc = mac_biba_create_mbuf_from_bpfdesc,
	.mpo_create_mbuf_from_ifnet = mac_biba_create_mbuf_from_ifnet,
	.mpo_create_mbuf_multicast_encap = mac_biba_create_mbuf_multicast_encap,
	.mpo_create_mbuf_netlayer = mac_biba_create_mbuf_netlayer,
	.mpo_fragment_match = mac_biba_fragment_match,
	.mpo_relabel_ifnet = mac_biba_relabel_ifnet,
	.mpo_update_ipq = mac_biba_update_ipq,
	.mpo_inpcb_sosetlabel = mac_biba_inpcb_sosetlabel,
	.mpo_create_proc0 = mac_biba_create_proc0,
	.mpo_create_proc1 = mac_biba_create_proc1,
	.mpo_relabel_cred = mac_biba_relabel_cred,
	.mpo_cleanup_sysv_msgmsg = mac_biba_cleanup_sysv_msgmsg,
	.mpo_cleanup_sysv_msgqueue = mac_biba_cleanup_sysv_msgqueue,
	.mpo_cleanup_sysv_sem = mac_biba_cleanup_sysv_sem,
	.mpo_cleanup_sysv_shm = mac_biba_cleanup_sysv_shm,
	.mpo_check_bpfdesc_receive = mac_biba_check_bpfdesc_receive,
	.mpo_check_cred_relabel = mac_biba_check_cred_relabel,
	.mpo_check_cred_visible = mac_biba_check_cred_visible,
	.mpo_check_ifnet_relabel = mac_biba_check_ifnet_relabel,
	.mpo_check_ifnet_transmit = mac_biba_check_ifnet_transmit,
	.mpo_check_inpcb_deliver = mac_biba_check_inpcb_deliver,
	.mpo_check_sysv_msgrcv = mac_biba_check_sysv_msgrcv,
	.mpo_check_sysv_msgrmid = mac_biba_check_sysv_msgrmid,
	.mpo_check_sysv_msqget = mac_biba_check_sysv_msqget,
	.mpo_check_sysv_msqsnd = mac_biba_check_sysv_msqsnd,
	.mpo_check_sysv_msqrcv = mac_biba_check_sysv_msqrcv,
	.mpo_check_sysv_msqctl = mac_biba_check_sysv_msqctl,
	.mpo_check_sysv_semctl = mac_biba_check_sysv_semctl,
	.mpo_check_sysv_semget = mac_biba_check_sysv_semget,
	.mpo_check_sysv_semop = mac_biba_check_sysv_semop,
	.mpo_check_sysv_shmat = mac_biba_check_sysv_shmat,
	.mpo_check_sysv_shmctl = mac_biba_check_sysv_shmctl,
	.mpo_check_sysv_shmget = mac_biba_check_sysv_shmget,
	.mpo_check_kld_load = mac_biba_check_kld_load,
	.mpo_check_kld_unload = mac_biba_check_kld_unload,
	.mpo_check_mount_stat = mac_biba_check_mount_stat,
	.mpo_check_pipe_ioctl = mac_biba_check_pipe_ioctl,
	.mpo_check_pipe_poll = mac_biba_check_pipe_poll,
	.mpo_check_pipe_read = mac_biba_check_pipe_read,
	.mpo_check_pipe_relabel = mac_biba_check_pipe_relabel,
	.mpo_check_pipe_stat = mac_biba_check_pipe_stat,
	.mpo_check_pipe_write = mac_biba_check_pipe_write,
	.mpo_check_posix_sem_destroy = mac_biba_check_posix_sem_write,
	.mpo_check_posix_sem_getvalue = mac_biba_check_posix_sem_rdonly,
	.mpo_check_posix_sem_open = mac_biba_check_posix_sem_write,
	.mpo_check_posix_sem_post = mac_biba_check_posix_sem_write,
	.mpo_check_posix_sem_unlink = mac_biba_check_posix_sem_write,
	.mpo_check_posix_sem_wait = mac_biba_check_posix_sem_write,
	.mpo_check_proc_debug = mac_biba_check_proc_debug,
	.mpo_check_proc_sched = mac_biba_check_proc_sched,
	.mpo_check_proc_signal = mac_biba_check_proc_signal,
	.mpo_check_socket_deliver = mac_biba_check_socket_deliver,
	.mpo_check_socket_relabel = mac_biba_check_socket_relabel,
	.mpo_check_socket_visible = mac_biba_check_socket_visible,
	.mpo_check_sysarch_ioperm = mac_biba_check_sysarch_ioperm,
	.mpo_check_system_acct = mac_biba_check_system_acct,
	.mpo_check_system_settime = mac_biba_check_system_settime,
	.mpo_check_system_swapon = mac_biba_check_system_swapon,
	.mpo_check_system_swapoff = mac_biba_check_system_swapoff,
	.mpo_check_system_sysctl = mac_biba_check_system_sysctl,
	.mpo_check_vnode_access = mac_biba_check_vnode_open,
	.mpo_check_vnode_chdir = mac_biba_check_vnode_chdir,
	.mpo_check_vnode_chroot = mac_biba_check_vnode_chroot,
	.mpo_check_vnode_create = mac_biba_check_vnode_create,
	.mpo_check_vnode_delete = mac_biba_check_vnode_delete,
	.mpo_check_vnode_deleteacl = mac_biba_check_vnode_deleteacl,
	.mpo_check_vnode_deleteextattr = mac_biba_check_vnode_deleteextattr,
	.mpo_check_vnode_exec = mac_biba_check_vnode_exec,
	.mpo_check_vnode_getacl = mac_biba_check_vnode_getacl,
	.mpo_check_vnode_getextattr = mac_biba_check_vnode_getextattr,
	.mpo_check_vnode_link = mac_biba_check_vnode_link,
	.mpo_check_vnode_listextattr = mac_biba_check_vnode_listextattr,
	.mpo_check_vnode_lookup = mac_biba_check_vnode_lookup,
	.mpo_check_vnode_mmap = mac_biba_check_vnode_mmap,
	.mpo_check_vnode_open = mac_biba_check_vnode_open,
	.mpo_check_vnode_poll = mac_biba_check_vnode_poll,
	.mpo_check_vnode_read = mac_biba_check_vnode_read,
	.mpo_check_vnode_readdir = mac_biba_check_vnode_readdir,
	.mpo_check_vnode_readlink = mac_biba_check_vnode_readlink,
	.mpo_check_vnode_relabel = mac_biba_check_vnode_relabel,
	.mpo_check_vnode_rename_from = mac_biba_check_vnode_rename_from,
	.mpo_check_vnode_rename_to = mac_biba_check_vnode_rename_to,
	.mpo_check_vnode_revoke = mac_biba_check_vnode_revoke,
	.mpo_check_vnode_setacl = mac_biba_check_vnode_setacl,
	.mpo_check_vnode_setextattr = mac_biba_check_vnode_setextattr,
	.mpo_check_vnode_setflags = mac_biba_check_vnode_setflags,
	.mpo_check_vnode_setmode = mac_biba_check_vnode_setmode,
	.mpo_check_vnode_setowner = mac_biba_check_vnode_setowner,
	.mpo_check_vnode_setutimes = mac_biba_check_vnode_setutimes,
	.mpo_check_vnode_stat = mac_biba_check_vnode_stat,
	.mpo_check_vnode_write = mac_biba_check_vnode_write,
	.mpo_associate_nfsd_label = mac_biba_associate_nfsd_label,
	.mpo_create_mbuf_from_firewall = mac_biba_create_mbuf_from_firewall,
};

MAC_POLICY_SET(&mac_biba_ops, mac_biba, "TrustedBSD MAC/Biba",
    MPC_LOADTIME_FLAG_NOTLATE | MPC_LOADTIME_FLAG_LABELMBUFS, &mac_biba_slot);