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/10.4/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
66 SYSCTL_DECL(_security_mac);
67
68 static SYSCTL_NODE(_security_mac, OID_AUTO, partition, CTLFLAG_RW, 0,
69 "TrustedBSD mac_partition policy controls");
70
71 static int partition_enabled = 1;
72 SYSCTL_INT(_security_mac_partition, OID_AUTO, enabled, CTLFLAG_RW,
73 &partition_enabled, 0, "Enforce partition policy");
74
75 static 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
79 static int
80 partition_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 */
110 static int
111 partition_cred_check_relabel(struct ucred *cred, struct label *newlabel)
112 {
113 int error;
114
115 error = 0;
116
117 /*
118 * Treat "" 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
137 static int
138 partition_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
147 static void
148 partition_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
157 static void
158 partition_cred_create_init(struct ucred *cred)
159 {
160
161 SLOT_SET(cred->cr_label, 0);
162 }
163
164 static void
165 partition_cred_create_swapper(struct ucred *cred)
166 {
167
168 SLOT_SET(cred->cr_label, 0);
169 }
170
171 static void
172 partition_cred_destroy_label(struct label *label)
173 {
174
175 SLOT_SET(label, 0);
176 }
177
178 static int
179 partition_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, "") == -1)
193 return (EINVAL);
194 }
195 return (0);
196 }
197
198 static void
199 partition_cred_init_label(struct label *label)
200 {
201
202 SLOT_SET(label, 0);
203 }
204
205 static int
206 partition_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
218 static void
219 partition_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
226 static int
227 partition_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
237 static int
238 partition_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
247 static int
248 partition_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
257 static int
258 partition_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
268 static int
269 partition_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
279 static int
280 partition_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
298 static 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
318 MAC_POLICY_SET(&partition_ops, mac_partition, "TrustedBSD MAC/Partition",
319 MPC_LOADTIME_FLAG_UNLOADOK, &partition_slot);
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