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
40 /*
41 * Developed by the TrustedBSD Project.
42 *
43 * Experiment with a partition-like model.
44 */
45
46 #include <sys/param.h>
47 #include <sys/kernel.h>
48 #include <sys/module.h>
49 #include <sys/priv.h>
50 #include <sys/proc.h>
51 #include <sys/sbuf.h>
52 #include <sys/socket.h>
53 #include <sys/socketvar.h>
54 #include <sys/systm.h>
55 #include <sys/sysctl.h>
56
57 #include <net/route.h>
58 #include <netinet/in.h>
59 #include <netinet/in_pcb.h>
60
61 #include <security/mac/mac_policy.h>
62 #include <security/mac_partition/mac_partition.h>
63
64 static SYSCTL_NODE(_security_mac, OID_AUTO, partition,
65 CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
66 "TrustedBSD mac_partition policy controls");
67
68 static int partition_enabled = 1;
69 SYSCTL_INT(_security_mac_partition, OID_AUTO, enabled, CTLFLAG_RW,
70 &partition_enabled, 0, "Enforce partition policy");
71
72 static int partition_slot;
73 #define SLOT(l) mac_label_get((l), partition_slot)
74 #define SLOT_SET(l, v) mac_label_set((l), partition_slot, (v))
75
76 static int
partition_check(struct label * subject,struct label * object)77 partition_check(struct label *subject, struct label *object)
78 {
79
80 if (partition_enabled == 0)
81 return (0);
82
83 if (subject == NULL)
84 return (0);
85
86 if (SLOT(subject) == 0)
87 return (0);
88
89 /*
90 * If the object label hasn't been allocated, then it's effectively
91 * not in a partition, and we know the subject is as it has a label
92 * and it's not 0, so reject.
93 */
94 if (object == NULL)
95 return (EPERM);
96
97 if (SLOT(subject) == SLOT(object))
98 return (0);
99
100 return (EPERM);
101 }
102
103 /*
104 * Object-specific entry points are sorted alphabetically by object type name
105 * and then by operation.
106 */
107 static int
partition_cred_check_relabel(struct ucred * cred,struct label * newlabel)108 partition_cred_check_relabel(struct ucred *cred, struct label *newlabel)
109 {
110 int error;
111
112 error = 0;
113
114 /*
115 * Treat "0" as a no-op request because it reflects an unset
116 * partition label. If we ever want to support switching back to an
117 * unpartitioned state for a process, we'll need to differentiate the
118 * "not in a partition" and "no partition defined during internalize"
119 * conditions.
120 */
121 if (SLOT(newlabel) != 0) {
122 /*
123 * Require BSD privilege in order to change the partition.
124 * Originally we also required that the process not be in a
125 * partition in the first place, but this didn't interact
126 * well with sendmail.
127 */
128 error = priv_check_cred(cred, PRIV_MAC_PARTITION);
129 }
130
131 return (error);
132 }
133
134 static int
partition_cred_check_visible(struct ucred * cr1,struct ucred * cr2)135 partition_cred_check_visible(struct ucred *cr1, struct ucred *cr2)
136 {
137 int error;
138
139 error = partition_check(cr1->cr_label, cr2->cr_label);
140
141 return (error == 0 ? 0 : ESRCH);
142 }
143
144 static void
partition_cred_copy_label(struct label * src,struct label * dest)145 partition_cred_copy_label(struct label *src, struct label *dest)
146 {
147
148 if (src != NULL && dest != NULL)
149 SLOT_SET(dest, SLOT(src));
150 else if (dest != NULL)
151 SLOT_SET(dest, 0);
152 }
153
154 static void
partition_cred_create_init(struct ucred * cred)155 partition_cred_create_init(struct ucred *cred)
156 {
157
158 SLOT_SET(cred->cr_label, 0);
159 }
160
161 static void
partition_cred_create_swapper(struct ucred * cred)162 partition_cred_create_swapper(struct ucred *cred)
163 {
164
165 SLOT_SET(cred->cr_label, 0);
166 }
167
168 static void
partition_cred_destroy_label(struct label * label)169 partition_cred_destroy_label(struct label *label)
170 {
171
172 SLOT_SET(label, 0);
173 }
174
175 static int
partition_cred_externalize_label(struct label * label,char * element_name,struct sbuf * sb,int * claimed)176 partition_cred_externalize_label(struct label *label, char *element_name,
177 struct sbuf *sb, int *claimed)
178 {
179
180 if (strcmp(MAC_PARTITION_LABEL_NAME, element_name) != 0)
181 return (0);
182
183 (*claimed)++;
184
185 if (label != NULL) {
186 if (sbuf_printf(sb, "%jd", (intmax_t)SLOT(label)) == -1)
187 return (EINVAL);
188 } else {
189 if (sbuf_printf(sb, "0") == -1)
190 return (EINVAL);
191 }
192 return (0);
193 }
194
195 static void
partition_cred_init_label(struct label * label)196 partition_cred_init_label(struct label *label)
197 {
198
199 SLOT_SET(label, 0);
200 }
201
202 static int
partition_cred_internalize_label(struct label * label,char * element_name,char * element_data,int * claimed)203 partition_cred_internalize_label(struct label *label, char *element_name,
204 char *element_data, int *claimed)
205 {
206
207 if (strcmp(MAC_PARTITION_LABEL_NAME, element_name) != 0)
208 return (0);
209
210 (*claimed)++;
211 SLOT_SET(label, strtol(element_data, NULL, 10));
212 return (0);
213 }
214
215 static void
partition_cred_relabel(struct ucred * cred,struct label * newlabel)216 partition_cred_relabel(struct ucred *cred, struct label *newlabel)
217 {
218
219 if (newlabel != NULL && SLOT(newlabel) != 0)
220 SLOT_SET(cred->cr_label, SLOT(newlabel));
221 }
222
223 static int
partition_inpcb_check_visible(struct ucred * cred,struct inpcb * inp,struct label * inplabel)224 partition_inpcb_check_visible(struct ucred *cred, struct inpcb *inp,
225 struct label *inplabel)
226 {
227 int error;
228
229 error = partition_check(cred->cr_label, inp->inp_cred->cr_label);
230
231 return (error ? ENOENT : 0);
232 }
233
234 static int
partition_proc_check_debug(struct ucred * cred,struct proc * p)235 partition_proc_check_debug(struct ucred *cred, struct proc *p)
236 {
237 int error;
238
239 error = partition_check(cred->cr_label, p->p_ucred->cr_label);
240
241 return (error ? ESRCH : 0);
242 }
243
244 static int
partition_proc_check_sched(struct ucred * cred,struct proc * p)245 partition_proc_check_sched(struct ucred *cred, struct proc *p)
246 {
247 int error;
248
249 error = partition_check(cred->cr_label, p->p_ucred->cr_label);
250
251 return (error ? ESRCH : 0);
252 }
253
254 static int
partition_proc_check_signal(struct ucred * cred,struct proc * p,int signum)255 partition_proc_check_signal(struct ucred *cred, struct proc *p,
256 int signum)
257 {
258 int error;
259
260 error = partition_check(cred->cr_label, p->p_ucred->cr_label);
261
262 return (error ? ESRCH : 0);
263 }
264
265 static int
partition_socket_check_visible(struct ucred * cred,struct socket * so,struct label * solabel)266 partition_socket_check_visible(struct ucred *cred, struct socket *so,
267 struct label *solabel)
268 {
269 int error;
270
271 error = partition_check(cred->cr_label, so->so_cred->cr_label);
272
273 return (error ? ENOENT : 0);
274 }
275
276 static int
partition_vnode_check_exec(struct ucred * cred,struct vnode * vp,struct label * vplabel,struct image_params * imgp,struct label * execlabel)277 partition_vnode_check_exec(struct ucred *cred, struct vnode *vp,
278 struct label *vplabel, struct image_params *imgp,
279 struct label *execlabel)
280 {
281
282 if (execlabel != NULL) {
283 /*
284 * We currently don't permit labels to be changed at
285 * exec-time as part of the partition model, so disallow
286 * non-NULL partition label changes in execlabel.
287 */
288 if (SLOT(execlabel) != 0)
289 return (EINVAL);
290 }
291
292 return (0);
293 }
294
295 static struct mac_policy_ops partition_ops =
296 {
297 .mpo_cred_check_relabel = partition_cred_check_relabel,
298 .mpo_cred_check_visible = partition_cred_check_visible,
299 .mpo_cred_copy_label = partition_cred_copy_label,
300 .mpo_cred_create_init = partition_cred_create_init,
301 .mpo_cred_create_swapper = partition_cred_create_swapper,
302 .mpo_cred_destroy_label = partition_cred_destroy_label,
303 .mpo_cred_externalize_label = partition_cred_externalize_label,
304 .mpo_cred_init_label = partition_cred_init_label,
305 .mpo_cred_internalize_label = partition_cred_internalize_label,
306 .mpo_cred_relabel = partition_cred_relabel,
307 .mpo_inpcb_check_visible = partition_inpcb_check_visible,
308 .mpo_proc_check_debug = partition_proc_check_debug,
309 .mpo_proc_check_sched = partition_proc_check_sched,
310 .mpo_proc_check_signal = partition_proc_check_signal,
311 .mpo_socket_check_visible = partition_socket_check_visible,
312 .mpo_vnode_check_exec = partition_vnode_check_exec,
313 };
314
315 MAC_POLICY_SET(&partition_ops, mac_partition, "TrustedBSD MAC/Partition",
316 MPC_LOADTIME_FLAG_UNLOADOK, &partition_slot);
317