freebsd-nq/sys/security/mac_seeotheruids/mac_seeotheruids.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

190 lines
5.7 KiB
C

/*-
* Copyright (c) 1999-2002, 2007 Robert N. M. Watson
* Copyright (c) 2001-2002 Networks Associates Technology, Inc.
* Copyright (c) 2006 SPARTA, Inc.
* All rights reserved.
*
* This software was developed by Robert Watson for the TrustedBSD Project.
*
* This software was developed for the FreeBSD Project in part by Network
* Associates Laboratories, the Security Research Division of Network
* Associates, Inc. under DARPA/SPAWAR contract N66001-01-C-8035 ("CBOSS"),
* as part of the DARPA CHATS research program.
*
* This software was enhanced by SPARTA ISSO under SPAWAR contract
* N66001-04-C-6019 ("SEFOS").
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* $FreeBSD$
*/
/*
* Developed by the TrustedBSD Project.
*
* Prevent processes owned by a particular uid from seeing various transient
* kernel objects associated with other uids.
*/
#include <sys/param.h>
#include <sys/kernel.h>
#include <sys/module.h>
#include <sys/priv.h>
#include <sys/proc.h>
#include <sys/systm.h>
#include <sys/socket.h>
#include <sys/socketvar.h>
#include <sys/sysctl.h>
#include <net/route.h>
#include <netinet/in.h>
#include <netinet/in_pcb.h>
#include <security/mac/mac_policy.h>
SYSCTL_DECL(_security_mac);
SYSCTL_NODE(_security_mac, OID_AUTO, seeotheruids, CTLFLAG_RW, 0,
"TrustedBSD mac_seeotheruids policy controls");
static int seeotheruids_enabled = 1;
SYSCTL_INT(_security_mac_seeotheruids, OID_AUTO, enabled, CTLFLAG_RW,
&seeotheruids_enabled, 0, "Enforce seeotheruids policy");
/*
* Exception: allow credentials to be aware of other credentials with the
* same primary gid.
*/
static int primarygroup_enabled = 0;
SYSCTL_INT(_security_mac_seeotheruids, OID_AUTO, primarygroup_enabled,
CTLFLAG_RW, &primarygroup_enabled, 0, "Make an exception for credentials "
"with the same real primary group id");
/*
* Exception: allow the root user to be aware of other credentials by virtue
* of privilege.
*/
static int suser_privileged = 1;
SYSCTL_INT(_security_mac_seeotheruids, OID_AUTO, suser_privileged,
CTLFLAG_RW, &suser_privileged, 0, "Make an exception for superuser");
/*
* Exception: allow processes with a specific gid to be exempt from the
* policy. One sysctl enables this functionality; the other sets the
* exempt gid.
*/
static int specificgid_enabled = 0;
SYSCTL_INT(_security_mac_seeotheruids, OID_AUTO, specificgid_enabled,
CTLFLAG_RW, &specificgid_enabled, 0, "Make an exception for credentials "
"with a specific gid as their real primary group id or group set");
static gid_t specificgid = 0;
SYSCTL_INT(_security_mac_seeotheruids, OID_AUTO, specificgid, CTLFLAG_RW,
&specificgid, 0, "Specific gid to be exempt from seeotheruids policy");
static int
seeotheruids_check(struct ucred *cr1, struct ucred *cr2)
{
if (!seeotheruids_enabled)
return (0);
if (primarygroup_enabled) {
if (cr1->cr_rgid == cr2->cr_rgid)
return (0);
}
if (specificgid_enabled) {
if (cr1->cr_rgid == specificgid ||
groupmember(specificgid, cr1))
return (0);
}
if (cr1->cr_ruid == cr2->cr_ruid)
return (0);
if (suser_privileged) {
if (priv_check_cred(cr1, PRIV_SEEOTHERUIDS, 0) == 0)
return (0);
}
return (ESRCH);
}
static int
seeotheruids_proc_check_debug(struct ucred *cred, struct proc *p)
{
return (seeotheruids_check(cred, p->p_ucred));
}
static int
seeotheruids_proc_check_sched(struct ucred *cred, struct proc *p)
{
return (seeotheruids_check(cred, p->p_ucred));
}
static int
seeotheruids_proc_check_signal(struct ucred *cred, struct proc *p,
int signum)
{
return (seeotheruids_check(cred, p->p_ucred));
}
static int
seeotheruids_cred_check_visible(struct ucred *cr1, struct ucred *cr2)
{
return (seeotheruids_check(cr1, cr2));
}
static int
seeotheruids_inpcb_check_visible(struct ucred *cred, struct inpcb *inp,
struct label *inplabel)
{
return (seeotheruids_check(cred, inp->inp_cred));
}
static int
seeotheruids_socket_check_visible(struct ucred *cred, struct socket *so,
struct label *solabel)
{
return (seeotheruids_check(cred, so->so_cred));
}
static struct mac_policy_ops seeotheruids_ops =
{
.mpo_proc_check_debug = seeotheruids_proc_check_debug,
.mpo_proc_check_sched = seeotheruids_proc_check_sched,
.mpo_proc_check_signal = seeotheruids_proc_check_signal,
.mpo_cred_check_visible = seeotheruids_cred_check_visible,
.mpo_inpcb_check_visible = seeotheruids_inpcb_check_visible,
.mpo_socket_check_visible = seeotheruids_socket_check_visible,
};
MAC_POLICY_SET(&seeotheruids_ops, mac_seeotheruids,
"TrustedBSD MAC/seeotheruids", MPC_LOADTIME_FLAG_UNLOADOK, NULL);