1/*-
2 * Copyright (c) 1999-2002, 2007-2008 Robert N. M. Watson
3 * Copyright (c) 2001-2002 Networks Associates Technology, Inc.
4 * Copyright (c) 2006 SPARTA, Inc.
5 * Copyright (c) 2008 Apple Inc.
6 * All rights reserved.
7 *
8 * This software was developed by Robert Watson for the TrustedBSD Project.
9 *
10 * This software was developed for the FreeBSD Project in part by Network
11 * Associates Laboratories, the Security Research Division of Network
12 * Associates, Inc. under DARPA/SPAWAR contract N66001-01-C-8035 ("CBOSS"),
13 * as part of the DARPA CHATS research program.
14 *
15 * This software was enhanced by SPARTA ISSO under SPAWAR contract
16 * N66001-04-C-6019 ("SEFOS").
17 *
18 * Redistribution and use in source and binary forms, with or without
19 * modification, are permitted provided that the following conditions
20 * are met:
21 * 1. Redistributions of source code must retain the above copyright
22 *    notice, this list of conditions and the following disclaimer.
23 * 2. Redistributions in binary form must reproduce the above copyright
24 *    notice, this list of conditions and the following disclaimer in the
25 *    documentation and/or other materials provided with the distribution.
26 *
27 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
28 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
29 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
30 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
31 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
32 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
33 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
34 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
35 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
36 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
37 * SUCH DAMAGE.
38 *
39 * $FreeBSD: releng/10.3/sys/security/mac_partition/mac_partition.c 227309 2011-11-07 15:43:11Z ed $
40 */
41
42/*
43 * Developed by the TrustedBSD Project.
44 *
45 * Experiment with a partition-like model.
46 */
47
48#include <sys/param.h>
49#include <sys/kernel.h>
50#include <sys/module.h>
51#include <sys/priv.h>
52#include <sys/proc.h>
53#include <sys/sbuf.h>
54#include <sys/socket.h>
55#include <sys/socketvar.h>
56#include <sys/systm.h>
57#include <sys/sysctl.h>
58
59#include <net/route.h>
60#include <netinet/in.h>
61#include <netinet/in_pcb.h>
62
63#include <security/mac/mac_policy.h>
64#include <security/mac_partition/mac_partition.h>
65
66SYSCTL_DECL(_security_mac);
67
68static SYSCTL_NODE(_security_mac, OID_AUTO, partition, CTLFLAG_RW, 0,
69    "TrustedBSD mac_partition policy controls");
70
71static int	partition_enabled = 1;
72SYSCTL_INT(_security_mac_partition, OID_AUTO, enabled, CTLFLAG_RW,
73    &partition_enabled, 0, "Enforce partition policy");
74
75static int	partition_slot;
76#define	SLOT(l)	mac_label_get((l), partition_slot)
77#define	SLOT_SET(l, v)	mac_label_set((l), partition_slot, (v))
78
79static int
80partition_check(struct label *subject, struct label *object)
81{
82
83	if (partition_enabled == 0)
84		return (0);
85
86	if (subject == NULL)
87		return (0);
88
89	if (SLOT(subject) == 0)
90		return (0);
91
92	/*
93	 * If the object label hasn't been allocated, then it's effectively
94	 * not in a partition, and we know the subject is as it has a label
95	 * and it's not 0, so reject.
96	 */
97	if (object == NULL)
98		return (EPERM);
99
100	if (SLOT(subject) == SLOT(object))
101		return (0);
102
103	return (EPERM);
104}
105
106/*
107 * Object-specific entry points are sorted alphabetically by object type name
108 * and then by operation.
109 */
110static int
111partition_cred_check_relabel(struct ucred *cred, struct label *newlabel)
112{
113	int error;
114
115	error = 0;
116
117	/*
118	 * Treat "0" as a no-op request because it reflects an unset
119	 * partition label.  If we ever want to support switching back to an
120	 * unpartitioned state for a process, we'll need to differentiate the
121	 * "not in a partition" and "no partition defined during internalize"
122	 * conditions.
123	 */
124	if (SLOT(newlabel) != 0) {
125		/*
126		 * Require BSD privilege in order to change the partition.
127		 * Originally we also required that the process not be in a
128		 * partition in the first place, but this didn't interact
129		 * well with sendmail.
130		 */
131		error = priv_check_cred(cred, PRIV_MAC_PARTITION, 0);
132	}
133
134	return (error);
135}
136
137static int
138partition_cred_check_visible(struct ucred *cr1, struct ucred *cr2)
139{
140	int error;
141
142	error = partition_check(cr1->cr_label, cr2->cr_label);
143
144	return (error == 0 ? 0 : ESRCH);
145}
146
147static void
148partition_cred_copy_label(struct label *src, struct label *dest)
149{
150
151	if (src != NULL && dest != NULL)
152		SLOT_SET(dest, SLOT(src));
153	else if (dest != NULL)
154		SLOT_SET(dest, 0);
155}
156
157static void
158partition_cred_create_init(struct ucred *cred)
159{
160
161	SLOT_SET(cred->cr_label, 0);
162}
163
164static void
165partition_cred_create_swapper(struct ucred *cred)
166{
167
168	SLOT_SET(cred->cr_label, 0);
169}
170
171static void
172partition_cred_destroy_label(struct label *label)
173{
174
175	SLOT_SET(label, 0);
176}
177
178static int
179partition_cred_externalize_label(struct label *label, char *element_name,
180    struct sbuf *sb, int *claimed)
181{
182
183	if (strcmp(MAC_PARTITION_LABEL_NAME, element_name) != 0)
184		return (0);
185
186	(*claimed)++;
187
188	if (label != NULL) {
189		if (sbuf_printf(sb, "%jd", (intmax_t)SLOT(label)) == -1)
190			return (EINVAL);
191	} else {
192		if (sbuf_printf(sb, "0") == -1)
193			return (EINVAL);
194	}
195	return (0);
196}
197
198static void
199partition_cred_init_label(struct label *label)
200{
201
202	SLOT_SET(label, 0);
203}
204
205static int
206partition_cred_internalize_label(struct label *label, char *element_name,
207    char *element_data, int *claimed)
208{
209
210	if (strcmp(MAC_PARTITION_LABEL_NAME, element_name) != 0)
211		return (0);
212
213	(*claimed)++;
214	SLOT_SET(label, strtol(element_data, NULL, 10));
215	return (0);
216}
217
218static void
219partition_cred_relabel(struct ucred *cred, struct label *newlabel)
220{
221
222	if (newlabel != NULL && SLOT(newlabel) != 0)
223		SLOT_SET(cred->cr_label, SLOT(newlabel));
224}
225
226static int
227partition_inpcb_check_visible(struct ucred *cred, struct inpcb *inp,
228    struct label *inplabel)
229{
230	int error;
231
232	error = partition_check(cred->cr_label, inp->inp_cred->cr_label);
233
234	return (error ? ENOENT : 0);
235}
236
237static int
238partition_proc_check_debug(struct ucred *cred, struct proc *p)
239{
240	int error;
241
242	error = partition_check(cred->cr_label, p->p_ucred->cr_label);
243
244	return (error ? ESRCH : 0);
245}
246
247static int
248partition_proc_check_sched(struct ucred *cred, struct proc *p)
249{
250	int error;
251
252	error = partition_check(cred->cr_label, p->p_ucred->cr_label);
253
254	return (error ? ESRCH : 0);
255}
256
257static int
258partition_proc_check_signal(struct ucred *cred, struct proc *p,
259    int signum)
260{
261	int error;
262
263	error = partition_check(cred->cr_label, p->p_ucred->cr_label);
264
265	return (error ? ESRCH : 0);
266}
267
268static int
269partition_socket_check_visible(struct ucred *cred, struct socket *so,
270    struct label *solabel)
271{
272	int error;
273
274	error = partition_check(cred->cr_label, so->so_cred->cr_label);
275
276	return (error ? ENOENT : 0);
277}
278
279static int
280partition_vnode_check_exec(struct ucred *cred, struct vnode *vp,
281    struct label *vplabel, struct image_params *imgp,
282    struct label *execlabel)
283{
284
285	if (execlabel != NULL) {
286		/*
287		 * We currently don't permit labels to be changed at
288		 * exec-time as part of the partition model, so disallow
289		 * non-NULL partition label changes in execlabel.
290		 */
291		if (SLOT(execlabel) != 0)
292			return (EINVAL);
293	}
294
295	return (0);
296}
297
298static struct mac_policy_ops partition_ops =
299{
300	.mpo_cred_check_relabel = partition_cred_check_relabel,
301	.mpo_cred_check_visible = partition_cred_check_visible,
302	.mpo_cred_copy_label = partition_cred_copy_label,
303	.mpo_cred_create_init = partition_cred_create_init,
304	.mpo_cred_create_swapper = partition_cred_create_swapper,
305	.mpo_cred_destroy_label = partition_cred_destroy_label,
306	.mpo_cred_externalize_label = partition_cred_externalize_label,
307	.mpo_cred_init_label = partition_cred_init_label,
308	.mpo_cred_internalize_label = partition_cred_internalize_label,
309	.mpo_cred_relabel = partition_cred_relabel,
310	.mpo_inpcb_check_visible = partition_inpcb_check_visible,
311	.mpo_proc_check_debug = partition_proc_check_debug,
312	.mpo_proc_check_sched = partition_proc_check_sched,
313	.mpo_proc_check_signal = partition_proc_check_signal,
314	.mpo_socket_check_visible = partition_socket_check_visible,
315	.mpo_vnode_check_exec = partition_vnode_check_exec,
316};
317
318MAC_POLICY_SET(&partition_ops, mac_partition, "TrustedBSD MAC/Partition",
319    MPC_LOADTIME_FLAG_UNLOADOK, &partition_slot);
320