freebsd-skq/sys/security/mac_partition/mac_partition.c
Robert Watson 9162f64b58 Rather than having MAC policies explicitly declare what object types
they label, derive that information implicitly from the set of label
initializers in their policy operations set.  This avoids a possible
class of programmer errors, while retaining the structure that
allows us to avoid allocating labels for objects that don't need
them.  As before, we regenerate a global mask of labeled objects
each time a policy is loaded or unloaded, stored in mac_labeled.

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

320 lines
8.2 KiB
C

/*-
* Copyright (c) 1999-2002, 2007-2008 Robert N. M. Watson
* Copyright (c) 2001-2002 Networks Associates Technology, Inc.
* Copyright (c) 2006 SPARTA, Inc.
* Copyright (c) 2008 Apple Inc.
* All rights reserved.
*
* This software was developed by Robert Watson for the TrustedBSD Project.
*
* This software was developed for the FreeBSD Project in part by Network
* Associates Laboratories, the Security Research Division of Network
* Associates, Inc. under DARPA/SPAWAR contract N66001-01-C-8035 ("CBOSS"),
* as part of the DARPA CHATS research program.
*
* This software was enhanced by SPARTA ISSO under SPAWAR contract
* N66001-04-C-6019 ("SEFOS").
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* $FreeBSD$
*/
/*
* Developed by the TrustedBSD Project.
*
* Experiment with a partition-like model.
*/
#include <sys/param.h>
#include <sys/kernel.h>
#include <sys/module.h>
#include <sys/priv.h>
#include <sys/proc.h>
#include <sys/sbuf.h>
#include <sys/socket.h>
#include <sys/socketvar.h>
#include <sys/systm.h>
#include <sys/sysctl.h>
#include <net/route.h>
#include <netinet/in.h>
#include <netinet/in_pcb.h>
#include <security/mac/mac_policy.h>
#include <security/mac_partition/mac_partition.h>
SYSCTL_DECL(_security_mac);
SYSCTL_NODE(_security_mac, OID_AUTO, partition, CTLFLAG_RW, 0,
"TrustedBSD mac_partition policy controls");
static int partition_enabled = 1;
SYSCTL_INT(_security_mac_partition, OID_AUTO, enabled, CTLFLAG_RW,
&partition_enabled, 0, "Enforce partition policy");
static int partition_slot;
#define SLOT(l) mac_label_get((l), partition_slot)
#define SLOT_SET(l, v) mac_label_set((l), partition_slot, (v))
static int
partition_check(struct label *subject, struct label *object)
{
if (partition_enabled == 0)
return (0);
if (subject == NULL)
return (0);
if (SLOT(subject) == 0)
return (0);
/*
* If the object label hasn't been allocated, then it's effectively
* not in a partition, and we know the subject is as it has a label
* and it's not 0, so reject.
*/
if (object == NULL)
return (EPERM);
if (SLOT(subject) == SLOT(object))
return (0);
return (EPERM);
}
/*
* Object-specific entry points are sorted alphabetically by object type name
* and then by operation.
*/
static int
partition_cred_check_relabel(struct ucred *cred, struct label *newlabel)
{
int error;
error = 0;
/*
* Treat "0" as a no-op request because it reflects an unset
* partition label. If we ever want to support switching back to an
* unpartitioned state for a process, we'll need to differentiate the
* "not in a partition" and "no partition defined during internalize"
* conditions.
*/
if (SLOT(newlabel) != 0) {
/*
* Require BSD privilege in order to change the partition.
* Originally we also required that the process not be in a
* partition in the first place, but this didn't interact
* well with sendmail.
*/
error = priv_check_cred(cred, PRIV_MAC_PARTITION, 0);
}
return (error);
}
static int
partition_cred_check_visible(struct ucred *cr1, struct ucred *cr2)
{
int error;
error = partition_check(cr1->cr_label, cr2->cr_label);
return (error == 0 ? 0 : ESRCH);
}
static void
partition_cred_copy_label(struct label *src, struct label *dest)
{
if (src != NULL && dest != NULL)
SLOT_SET(dest, SLOT(src));
else if (dest != NULL)
SLOT_SET(dest, 0);
}
static void
partition_cred_create_init(struct ucred *cred)
{
SLOT_SET(cred->cr_label, 0);
}
static void
partition_cred_create_swapper(struct ucred *cred)
{
SLOT_SET(cred->cr_label, 0);
}
static void
partition_cred_destroy_label(struct label *label)
{
SLOT_SET(label, 0);
}
static int
partition_cred_externalize_label(struct label *label, char *element_name,
struct sbuf *sb, int *claimed)
{
if (strcmp(MAC_PARTITION_LABEL_NAME, element_name) != 0)
return (0);
(*claimed)++;
if (label != NULL) {
if (sbuf_printf(sb, "%jd", (intmax_t)SLOT(label)) == -1)
return (EINVAL);
} else {
if (sbuf_printf(sb, "0") == -1)
return (EINVAL);
}
return (0);
}
static void
partition_cred_init_label(struct label *label)
{
SLOT_SET(label, 0);
}
static int
partition_cred_internalize_label(struct label *label, char *element_name,
char *element_data, int *claimed)
{
if (strcmp(MAC_PARTITION_LABEL_NAME, element_name) != 0)
return (0);
(*claimed)++;
SLOT_SET(label, strtol(element_data, NULL, 10));
return (0);
}
static void
partition_cred_relabel(struct ucred *cred, struct label *newlabel)
{
if (newlabel != NULL && SLOT(newlabel) != 0)
SLOT_SET(cred->cr_label, SLOT(newlabel));
}
static int
partition_inpcb_check_visible(struct ucred *cred, struct inpcb *inp,
struct label *inplabel)
{
int error;
error = partition_check(cred->cr_label, inp->inp_cred->cr_label);
return (error ? ENOENT : 0);
}
static int
partition_proc_check_debug(struct ucred *cred, struct proc *p)
{
int error;
error = partition_check(cred->cr_label, p->p_ucred->cr_label);
return (error ? ESRCH : 0);
}
static int
partition_proc_check_sched(struct ucred *cred, struct proc *p)
{
int error;
error = partition_check(cred->cr_label, p->p_ucred->cr_label);
return (error ? ESRCH : 0);
}
static int
partition_proc_check_signal(struct ucred *cred, struct proc *p,
int signum)
{
int error;
error = partition_check(cred->cr_label, p->p_ucred->cr_label);
return (error ? ESRCH : 0);
}
static int
partition_socket_check_visible(struct ucred *cred, struct socket *so,
struct label *solabel)
{
int error;
error = partition_check(cred->cr_label, so->so_cred->cr_label);
return (error ? ENOENT : 0);
}
static int
partition_vnode_check_exec(struct ucred *cred, struct vnode *vp,
struct label *vplabel, struct image_params *imgp,
struct label *execlabel)
{
if (execlabel != NULL) {
/*
* We currently don't permit labels to be changed at
* exec-time as part of the partition model, so disallow
* non-NULL partition label changes in execlabel.
*/
if (SLOT(execlabel) != 0)
return (EINVAL);
}
return (0);
}
static struct mac_policy_ops partition_ops =
{
.mpo_cred_check_relabel = partition_cred_check_relabel,
.mpo_cred_check_visible = partition_cred_check_visible,
.mpo_cred_copy_label = partition_cred_copy_label,
.mpo_cred_create_init = partition_cred_create_init,
.mpo_cred_create_swapper = partition_cred_create_swapper,
.mpo_cred_destroy_label = partition_cred_destroy_label,
.mpo_cred_externalize_label = partition_cred_externalize_label,
.mpo_cred_init_label = partition_cred_init_label,
.mpo_cred_internalize_label = partition_cred_internalize_label,
.mpo_cred_relabel = partition_cred_relabel,
.mpo_inpcb_check_visible = partition_inpcb_check_visible,
.mpo_proc_check_debug = partition_proc_check_debug,
.mpo_proc_check_sched = partition_proc_check_sched,
.mpo_proc_check_signal = partition_proc_check_signal,
.mpo_socket_check_visible = partition_socket_check_visible,
.mpo_vnode_check_exec = partition_vnode_check_exec,
};
MAC_POLICY_SET(&partition_ops, mac_partition, "TrustedBSD MAC/Partition",
MPC_LOADTIME_FLAG_UNLOADOK, &partition_slot);