mac_seeotheruids.c revision 106393 
1/*-
2 * Copyright (c) 1999, 2000, 2001, 2002 Robert N. M. Watson
3 * Copyright (c) 2001, 2002 Networks Associates Technology, Inc.
4 * All rights reserved.
5 *
6 * This software was developed by Robert Watson for the TrustedBSD Project.
7 *
8 * This software was developed for the FreeBSD Project in part by Network
9 * Associates Laboratories, the Security Research Division of Network
10 * Associates, Inc. under DARPA/SPAWAR contract N66001-01-C-8035 ("CBOSS"),
11 * as part of the DARPA CHATS research program.
12 *
13 * Redistribution and use in source and binary forms, with or without
14 * modification, are permitted provided that the following conditions
15 * are met:
16 * 1. Redistributions of source code must retain the above copyright
17 *    notice, this list of conditions and the following disclaimer.
18 * 2. Redistributions in binary form must reproduce the above copyright
19 *    notice, this list of conditions and the following disclaimer in the
20 *    documentation and/or other materials provided with the distribution.
21 *
22 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32 * SUCH DAMAGE.
33 *
34 * $FreeBSD: head/sys/security/mac_seeotheruids/mac_seeotheruids.c 106393 2002-11-04 01:53:12Z rwatson $
35 */
36
37/*
38 * Developed by the TrustedBSD Project.
39 * Prevent processes owned by a particular uid from seeing various transient
40 * kernel objects associated with other uids.
41 */
42
43#include <sys/types.h>
44#include <sys/param.h>
45#include <sys/conf.h>
46#include <sys/kernel.h>
47#include <sys/mac.h>
48#include <sys/mount.h>
49#include <sys/proc.h>
50#include <sys/systm.h>
51#include <sys/sysproto.h>
52#include <sys/sysent.h>
53#include <sys/vnode.h>
54#include <sys/file.h>
55#include <sys/socket.h>
56#include <sys/socketvar.h>
57#include <sys/sysctl.h>
58
59#include <net/bpfdesc.h>
60#include <net/if.h>
61#include <net/if_types.h>
62#include <net/if_var.h>
63
64#include <vm/vm.h>
65
66#include <sys/mac_policy.h>
67
68SYSCTL_DECL(_security_mac);
69
70SYSCTL_NODE(_security_mac, OID_AUTO, seeotheruids, CTLFLAG_RW, 0,
71    "TrustedBSD mac_seeotheruids policy controls");
72
73static int	mac_seeotheruids_enabled = 0;
74SYSCTL_INT(_security_mac_seeotheruids, OID_AUTO, enabled, CTLFLAG_RW,
75    &mac_seeotheruids_enabled, 0, "Enforce seeotheruids policy");
76
77/*
78 * Exception: allow credentials to be aware of other credentials with the
79 * same primary gid.
80 */
81static int	primarygroup_enabled = 0;
82SYSCTL_INT(_security_mac_seeotheruids, OID_AUTO, primarygroup_enabled,
83    CTLFLAG_RW, &primarygroup_enabled, 0, "Make an exception for credentials "
84    "with the same real primary group id");
85
86/*
87 * Exception: allow processes with a specific gid to be exempt from the
88 * policy.  One sysctl enables this functionality; the other sets the
89 * exempt gid.
90 */
91static int	specificgid_enabled = 0;
92SYSCTL_INT(_security_mac_seeotheruids, OID_AUTO, specificgid_enabled,
93    CTLFLAG_RW, &specificgid_enabled, 0, "Make an exception for credentials "
94    "with a specific gid as their real primary group id or group set");
95
96static gid_t	specificgid = 0;
97SYSCTL_INT(_security_mac_seeotheruids, OID_AUTO, specificgid, CTLFLAG_RW,
98    &specificgid, 0, "Specific gid to be exempt from seeotheruids policy");
99
100static int
101mac_seeotheruids_check(struct ucred *u1, struct ucred *u2)
102{
103
104	if (!mac_seeotheruids_enabled)
105		return (0);
106
107	if (primarygroup_enabled) {
108		if (u1->cr_rgid == u2->cr_rgid)
109			return (0);
110	}
111
112	if (specificgid_enabled) {
113		if (u1->cr_rgid == specificgid || groupmember(specificgid, u1))
114			return (0);
115	}
116
117	if (u1->cr_ruid == u2->cr_ruid)
118		return (0);
119
120	return (ESRCH);
121}
122
123static int
124mac_seeotheruids_check_cred_visible(struct ucred *u1, struct ucred *u2)
125{
126
127	return (mac_seeotheruids_check(u1, u2));
128}
129
130static int
131mac_seeotheruids_check_proc_signal(struct ucred *cred, struct proc *proc,
132    int signum)
133{
134
135	return (mac_seeotheruids_check(cred, proc->p_ucred));
136}
137
138static int
139mac_seeotheruids_check_proc_sched(struct ucred *cred, struct proc *proc)
140{
141
142	return (mac_seeotheruids_check(cred, proc->p_ucred));
143}
144
145static int
146mac_seeotheruids_check_proc_debug(struct ucred *cred, struct proc *proc)
147{
148
149	return (mac_seeotheruids_check(cred, proc->p_ucred));
150}
151
152static int
153mac_seeotheruids_check_socket_visible(struct ucred *cred, struct socket *socket,
154    struct label *socketlabel)
155{
156
157	return (mac_seeotheruids_check(cred, socket->so_cred));
158}
159
160static struct mac_policy_ops mac_seeotheruids_ops =
161{
162	.mpo_check_cred_visible = mac_seeotheruids_check_cred_visible,
163	.mpo_check_proc_debug = mac_seeotheruids_check_proc_debug,
164	.mpo_check_proc_sched = mac_seeotheruids_check_proc_sched,
165	.mpo_check_proc_signal = mac_seeotheruids_check_proc_signal,
166	.mpo_check_socket_visible = mac_seeotheruids_check_socket_visible,
167};
168
169MAC_POLICY_SET(&mac_seeotheruids_ops, trustedbsd_mac_seeotheruids,
170    "TrustedBSD MAC/seeotheruids", MPC_LOADTIME_FLAG_UNLOADOK, NULL);
171