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 * $FreeBSD$
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,
69    CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
70    "TrustedBSD mac_partition policy controls");
71
72static int	partition_enabled = 1;
73SYSCTL_INT(_security_mac_partition, OID_AUTO, enabled, CTLFLAG_RW,
74    &partition_enabled, 0, "Enforce partition policy");
75
76static int	partition_slot;
77#define	SLOT(l)	mac_label_get((l), partition_slot)
78#define	SLOT_SET(l, v)	mac_label_set((l), partition_slot, (v))
79
80static int
81partition_check(struct label *subject, struct label *object)
82{
83
84	if (partition_enabled == 0)
85		return (0);
86
87	if (subject == NULL)
88		return (0);
89
90	if (SLOT(subject) == 0)
91		return (0);
92
93	/*
94	 * If the object label hasn't been allocated, then it's effectively
95	 * not in a partition, and we know the subject is as it has a label
96	 * and it's not 0, so reject.
97	 */
98	if (object == NULL)
99		return (EPERM);
100
101	if (SLOT(subject) == SLOT(object))
102		return (0);
103
104	return (EPERM);
105}
106
107/*
108 * Object-specific entry points are sorted alphabetically by object type name
109 * and then by operation.
110 */
111static int
112partition_cred_check_relabel(struct ucred *cred, struct label *newlabel)
113{
114	int error;
115
116	error = 0;
117
118	/*
119	 * Treat "0" as a no-op request because it reflects an unset
120	 * partition label.  If we ever want to support switching back to an
121	 * unpartitioned state for a process, we'll need to differentiate the
122	 * "not in a partition" and "no partition defined during internalize"
123	 * conditions.
124	 */
125	if (SLOT(newlabel) != 0) {
126		/*
127		 * Require BSD privilege in order to change the partition.
128		 * Originally we also required that the process not be in a
129		 * partition in the first place, but this didn't interact
130		 * well with sendmail.
131		 */
132		error = priv_check_cred(cred, PRIV_MAC_PARTITION);
133	}
134
135	return (error);
136}
137
138static int
139partition_cred_check_visible(struct ucred *cr1, struct ucred *cr2)
140{
141	int error;
142
143	error = partition_check(cr1->cr_label, cr2->cr_label);
144
145	return (error == 0 ? 0 : ESRCH);
146}
147
148static void
149partition_cred_copy_label(struct label *src, struct label *dest)
150{
151
152	if (src != NULL && dest != NULL)
153		SLOT_SET(dest, SLOT(src));
154	else if (dest != NULL)
155		SLOT_SET(dest, 0);
156}
157
158static void
159partition_cred_create_init(struct ucred *cred)
160{
161
162	SLOT_SET(cred->cr_label, 0);
163}
164
165static void
166partition_cred_create_swapper(struct ucred *cred)
167{
168
169	SLOT_SET(cred->cr_label, 0);
170}
171
172static void
173partition_cred_destroy_label(struct label *label)
174{
175
176	SLOT_SET(label, 0);
177}
178
179static int
180partition_cred_externalize_label(struct label *label, char *element_name,
181    struct sbuf *sb, int *claimed)
182{
183
184	if (strcmp(MAC_PARTITION_LABEL_NAME, element_name) != 0)
185		return (0);
186
187	(*claimed)++;
188
189	if (label != NULL) {
190		if (sbuf_printf(sb, "%jd", (intmax_t)SLOT(label)) == -1)
191			return (EINVAL);
192	} else {
193		if (sbuf_printf(sb, "0") == -1)
194			return (EINVAL);
195	}
196	return (0);
197}
198
199static void
200partition_cred_init_label(struct label *label)
201{
202
203	SLOT_SET(label, 0);
204}
205
206static int
207partition_cred_internalize_label(struct label *label, char *element_name,
208    char *element_data, int *claimed)
209{
210
211	if (strcmp(MAC_PARTITION_LABEL_NAME, element_name) != 0)
212		return (0);
213
214	(*claimed)++;
215	SLOT_SET(label, strtol(element_data, NULL, 10));
216	return (0);
217}
218
219static void
220partition_cred_relabel(struct ucred *cred, struct label *newlabel)
221{
222
223	if (newlabel != NULL && SLOT(newlabel) != 0)
224		SLOT_SET(cred->cr_label, SLOT(newlabel));
225}
226
227static int
228partition_inpcb_check_visible(struct ucred *cred, struct inpcb *inp,
229    struct label *inplabel)
230{
231	int error;
232
233	error = partition_check(cred->cr_label, inp->inp_cred->cr_label);
234
235	return (error ? ENOENT : 0);
236}
237
238static int
239partition_proc_check_debug(struct ucred *cred, struct proc *p)
240{
241	int error;
242
243	error = partition_check(cred->cr_label, p->p_ucred->cr_label);
244
245	return (error ? ESRCH : 0);
246}
247
248static int
249partition_proc_check_sched(struct ucred *cred, struct proc *p)
250{
251	int error;
252
253	error = partition_check(cred->cr_label, p->p_ucred->cr_label);
254
255	return (error ? ESRCH : 0);
256}
257
258static int
259partition_proc_check_signal(struct ucred *cred, struct proc *p,
260    int signum)
261{
262	int error;
263
264	error = partition_check(cred->cr_label, p->p_ucred->cr_label);
265
266	return (error ? ESRCH : 0);
267}
268
269static int
270partition_socket_check_visible(struct ucred *cred, struct socket *so,
271    struct label *solabel)
272{
273	int error;
274
275	error = partition_check(cred->cr_label, so->so_cred->cr_label);
276
277	return (error ? ENOENT : 0);
278}
279
280static int
281partition_vnode_check_exec(struct ucred *cred, struct vnode *vp,
282    struct label *vplabel, struct image_params *imgp,
283    struct label *execlabel)
284{
285
286	if (execlabel != NULL) {
287		/*
288		 * We currently don't permit labels to be changed at
289		 * exec-time as part of the partition model, so disallow
290		 * non-NULL partition label changes in execlabel.
291		 */
292		if (SLOT(execlabel) != 0)
293			return (EINVAL);
294	}
295
296	return (0);
297}
298
299static struct mac_policy_ops partition_ops =
300{
301	.mpo_cred_check_relabel = partition_cred_check_relabel,
302	.mpo_cred_check_visible = partition_cred_check_visible,
303	.mpo_cred_copy_label = partition_cred_copy_label,
304	.mpo_cred_create_init = partition_cred_create_init,
305	.mpo_cred_create_swapper = partition_cred_create_swapper,
306	.mpo_cred_destroy_label = partition_cred_destroy_label,
307	.mpo_cred_externalize_label = partition_cred_externalize_label,
308	.mpo_cred_init_label = partition_cred_init_label,
309	.mpo_cred_internalize_label = partition_cred_internalize_label,
310	.mpo_cred_relabel = partition_cred_relabel,
311	.mpo_inpcb_check_visible = partition_inpcb_check_visible,
312	.mpo_proc_check_debug = partition_proc_check_debug,
313	.mpo_proc_check_sched = partition_proc_check_sched,
314	.mpo_proc_check_signal = partition_proc_check_signal,
315	.mpo_socket_check_visible = partition_socket_check_visible,
316	.mpo_vnode_check_exec = partition_vnode_check_exec,
317};
318
319MAC_POLICY_SET(&partition_ops, mac_partition, "TrustedBSD MAC/Partition",
320    MPC_LOADTIME_FLAG_UNLOADOK, &partition_slot);
321