mac_partition.c revision 184401 
1/*-
2 * Copyright (c) 1999-2002, 2007 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: head/sys/security/mac_partition/mac_partition.c 184401 2008-10-28 09:12:13Z rwatson $
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
68SYSCTL_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	/* Treat "0" as a no-op request. */
118	if (SLOT(newlabel) != 0) {
119		/*
120		 * Require BSD privilege in order to change the partition.
121		 * Originally we also required that the process not be in a
122		 * partition in the first place, but this didn't interact
123		 * well with sendmail.
124		 */
125		error = priv_check_cred(cred, PRIV_MAC_PARTITION, 0);
126	}
127
128	return (error);
129}
130
131static int
132partition_cred_check_visible(struct ucred *cr1, struct ucred *cr2)
133{
134	int error;
135
136	error = partition_check(cr1->cr_label, cr2->cr_label);
137
138	return (error == 0 ? 0 : ESRCH);
139}
140
141static void
142partition_cred_copy_label(struct label *src, struct label *dest)
143{
144
145	if (src != NULL && dest != NULL)
146		SLOT_SET(dest, SLOT(src));
147	else if (dest != NULL)
148		SLOT_SET(dest, 0);
149}
150
151static void
152partition_cred_destroy_label(struct label *label)
153{
154
155	SLOT_SET(label, 0);
156}
157
158static int
159partition_cred_externalize_label(struct label *label, char *element_name,
160    struct sbuf *sb, int *claimed)
161{
162
163	if (strcmp(MAC_PARTITION_LABEL_NAME, element_name) != 0)
164		return (0);
165
166	(*claimed)++;
167
168	if (label != NULL) {
169		if (sbuf_printf(sb, "%jd", (intmax_t)SLOT(label)) == -1)
170			return (EINVAL);
171	} else {
172		if (sbuf_printf(sb, "0") == -1)
173			return (EINVAL);
174	}
175	return (0);
176}
177
178static void
179partition_cred_init_label(struct label *label)
180{
181
182	SLOT_SET(label, 0);
183}
184
185static int
186partition_cred_internalize_label(struct label *label, char *element_name,
187    char *element_data, int *claimed)
188{
189
190	if (strcmp(MAC_PARTITION_LABEL_NAME, element_name) != 0)
191		return (0);
192
193	(*claimed)++;
194	SLOT_SET(label, strtol(element_data, NULL, 10));
195	return (0);
196}
197
198static void
199partition_cred_relabel(struct ucred *cred, struct label *newlabel)
200{
201
202	if (newlabel != NULL && SLOT(newlabel) != 0)
203		SLOT_SET(cred->cr_label, SLOT(newlabel));
204}
205
206static int
207partition_inpcb_check_visible(struct ucred *cred, struct inpcb *inp,
208    struct label *inplabel)
209{
210	int error;
211
212	error = partition_check(cred->cr_label, inp->inp_cred->cr_label);
213
214	return (error ? ENOENT : 0);
215}
216
217static int
218partition_proc_check_debug(struct ucred *cred, struct proc *p)
219{
220	int error;
221
222	error = partition_check(cred->cr_label, p->p_ucred->cr_label);
223
224	return (error ? ESRCH : 0);
225}
226
227static int
228partition_proc_check_sched(struct ucred *cred, struct proc *p)
229{
230	int error;
231
232	error = partition_check(cred->cr_label, p->p_ucred->cr_label);
233
234	return (error ? ESRCH : 0);
235}
236
237static int
238partition_proc_check_signal(struct ucred *cred, struct proc *p,
239    int signum)
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 void
249partition_proc_create_init(struct ucred *cred)
250{
251
252	SLOT_SET(cred->cr_label, 0);
253}
254
255static void
256partition_proc_create_swapper(struct ucred *cred)
257{
258
259	SLOT_SET(cred->cr_label, 0);
260}
261
262static int
263partition_socket_check_visible(struct ucred *cred, struct socket *so,
264    struct label *solabel)
265{
266	int error;
267
268	error = partition_check(cred->cr_label, so->so_cred->cr_label);
269
270	return (error ? ENOENT : 0);
271}
272
273static int
274partition_vnode_check_exec(struct ucred *cred, struct vnode *vp,
275    struct label *vplabel, struct image_params *imgp,
276    struct label *execlabel)
277{
278
279	if (execlabel != NULL) {
280		/*
281		 * We currently don't permit labels to be changed at
282		 * exec-time as part of the partition model, so disallow
283		 * non-NULL partition label changes in execlabel.
284		 */
285		if (SLOT(execlabel) != 0)
286			return (EINVAL);
287	}
288
289	return (0);
290}
291
292static struct mac_policy_ops partition_ops =
293{
294	.mpo_cred_check_relabel = partition_cred_check_relabel,
295	.mpo_cred_check_visible = partition_cred_check_visible,
296	.mpo_cred_copy_label = partition_cred_copy_label,
297	.mpo_cred_destroy_label = partition_cred_destroy_label,
298	.mpo_cred_externalize_label = partition_cred_externalize_label,
299	.mpo_cred_init_label = partition_cred_init_label,
300	.mpo_cred_internalize_label = partition_cred_internalize_label,
301	.mpo_cred_relabel = partition_cred_relabel,
302	.mpo_inpcb_check_visible = partition_inpcb_check_visible,
303	.mpo_proc_check_debug = partition_proc_check_debug,
304	.mpo_proc_check_sched = partition_proc_check_sched,
305	.mpo_proc_check_signal = partition_proc_check_signal,
306	.mpo_proc_create_init = partition_proc_create_init,
307	.mpo_proc_create_swapper = partition_proc_create_swapper,
308	.mpo_socket_check_visible = partition_socket_check_visible,
309	.mpo_vnode_check_exec = partition_vnode_check_exec,
310};
311
312MAC_POLICY_SET(&partition_ops, mac_partition, "TrustedBSD MAC/Partition",
313    MPC_LOADTIME_FLAG_UNLOADOK, &partition_slot, MPC_OBJECT_CRED);
314