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 SYSCTL_DECL(_security_mac);
65
66 static SYSCTL_NODE(_security_mac, OID_AUTO, partition,
67 CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
68 "TrustedBSD mac_partition policy controls");
69
70 static int partition_enabled = 1;
71 SYSCTL_INT(_security_mac_partition, OID_AUTO, enabled, CTLFLAG_RW,
72 &partition_enabled, 0, "Enforce partition policy");
73
74 static int partition_slot;
75 #define SLOT(l) mac_label_get((l), partition_slot)
76 #define SLOT_SET(l, v) mac_label_set((l), partition_slot, (v))
77
78 static int
partition_check(struct label * subject,struct label * object)79 partition_check(struct label *subject, struct label *object)
80 {
81
82 if (partition_enabled == 0)
83 return (0);
84
85 if (subject == NULL)
86 return (0);
87
88 if (SLOT(subject) == 0)
89 return (0);
90
91 /*
92 * If the object label hasn't been allocated, then it's effectively
93 * not in a partition, and we know the subject is as it has a label
94 * and it's not 0, so reject.
95 */
96 if (object == NULL)
97 return (EPERM);
98
99 if (SLOT(subject) == SLOT(object))
100 return (0);
101
102 return (EPERM);
103 }
104
105 /*
106 * Object-specific entry points are sorted alphabetically by object type name
107 * and then by operation.
108 */
109 static int
partition_cred_check_relabel(struct ucred * cred,struct label * newlabel)110 partition_cred_check_relabel(struct ucred *cred, struct label *newlabel)
111 {
112 int error;
113
114 error = 0;
115
116 /*
117 * Treat "0" as a no-op request because it reflects an unset
118 * partition label. If we ever want to support switching back to an
119 * unpartitioned state for a process, we'll need to differentiate the
120 * "not in a partition" and "no partition defined during internalize"
121 * conditions.
122 */
123 if (SLOT(newlabel) != 0) {
124 /*
125 * Require BSD privilege in order to change the partition.
126 * Originally we also required that the process not be in a
127 * partition in the first place, but this didn't interact
128 * well with sendmail.
129 */
130 error = priv_check_cred(cred, PRIV_MAC_PARTITION);
131 }
132
133 return (error);
134 }
135
136 static int
partition_cred_check_visible(struct ucred * cr1,struct ucred * cr2)137 partition_cred_check_visible(struct ucred *cr1, struct ucred *cr2)
138 {
139 int error;
140
141 error = partition_check(cr1->cr_label, cr2->cr_label);
142
143 return (error == 0 ? 0 : ESRCH);
144 }
145
146 static void
partition_cred_copy_label(struct label * src,struct label * dest)147 partition_cred_copy_label(struct label *src, struct label *dest)
148 {
149
150 if (src != NULL && dest != NULL)
151 SLOT_SET(dest, SLOT(src));
152 else if (dest != NULL)
153 SLOT_SET(dest, 0);
154 }
155
156 static void
partition_cred_create_init(struct ucred * cred)157 partition_cred_create_init(struct ucred *cred)
158 {
159
160 SLOT_SET(cred->cr_label, 0);
161 }
162
163 static void
partition_cred_create_swapper(struct ucred * cred)164 partition_cred_create_swapper(struct ucred *cred)
165 {
166
167 SLOT_SET(cred->cr_label, 0);
168 }
169
170 static void
partition_cred_destroy_label(struct label * label)171 partition_cred_destroy_label(struct label *label)
172 {
173
174 SLOT_SET(label, 0);
175 }
176
177 static int
partition_cred_externalize_label(struct label * label,char * element_name,struct sbuf * sb,int * claimed)178 partition_cred_externalize_label(struct label *label, char *element_name,
179 struct sbuf *sb, int *claimed)
180 {
181
182 if (strcmp(MAC_PARTITION_LABEL_NAME, element_name) != 0)
183 return (0);
184
185 (*claimed)++;
186
187 if (label != NULL) {
188 if (sbuf_printf(sb, "%jd", (intmax_t)SLOT(label)) == -1)
189 return (EINVAL);
190 } else {
191 if (sbuf_printf(sb, "0") == -1)
192 return (EINVAL);
193 }
194 return (0);
195 }
196
197 static void
partition_cred_init_label(struct label * label)198 partition_cred_init_label(struct label *label)
199 {
200
201 SLOT_SET(label, 0);
202 }
203
204 static int
partition_cred_internalize_label(struct label * label,char * element_name,char * element_data,int * claimed)205 partition_cred_internalize_label(struct label *label, char *element_name,
206 char *element_data, int *claimed)
207 {
208
209 if (strcmp(MAC_PARTITION_LABEL_NAME, element_name) != 0)
210 return (0);
211
212 (*claimed)++;
213 SLOT_SET(label, strtol(element_data, NULL, 10));
214 return (0);
215 }
216
217 static void
partition_cred_relabel(struct ucred * cred,struct label * newlabel)218 partition_cred_relabel(struct ucred *cred, struct label *newlabel)
219 {
220
221 if (newlabel != NULL && SLOT(newlabel) != 0)
222 SLOT_SET(cred->cr_label, SLOT(newlabel));
223 }
224
225 static int
partition_inpcb_check_visible(struct ucred * cred,struct inpcb * inp,struct label * inplabel)226 partition_inpcb_check_visible(struct ucred *cred, struct inpcb *inp,
227 struct label *inplabel)
228 {
229 int error;
230
231 error = partition_check(cred->cr_label, inp->inp_cred->cr_label);
232
233 return (error ? ENOENT : 0);
234 }
235
236 static int
partition_proc_check_debug(struct ucred * cred,struct proc * p)237 partition_proc_check_debug(struct ucred *cred, struct proc *p)
238 {
239 int error;
240
241 error = partition_check(cred->cr_label, p->p_ucred->cr_label);
242
243 return (error ? ESRCH : 0);
244 }
245
246 static int
partition_proc_check_sched(struct ucred * cred,struct proc * p)247 partition_proc_check_sched(struct ucred *cred, struct proc *p)
248 {
249 int error;
250
251 error = partition_check(cred->cr_label, p->p_ucred->cr_label);
252
253 return (error ? ESRCH : 0);
254 }
255
256 static int
partition_proc_check_signal(struct ucred * cred,struct proc * p,int signum)257 partition_proc_check_signal(struct ucred *cred, struct proc *p,
258 int signum)
259 {
260 int error;
261
262 error = partition_check(cred->cr_label, p->p_ucred->cr_label);
263
264 return (error ? ESRCH : 0);
265 }
266
267 static int
partition_socket_check_visible(struct ucred * cred,struct socket * so,struct label * solabel)268 partition_socket_check_visible(struct ucred *cred, struct socket *so,
269 struct label *solabel)
270 {
271 int error;
272
273 error = partition_check(cred->cr_label, so->so_cred->cr_label);
274
275 return (error ? ENOENT : 0);
276 }
277
278 static int
partition_vnode_check_exec(struct ucred * cred,struct vnode * vp,struct label * vplabel,struct image_params * imgp,struct label * execlabel)279 partition_vnode_check_exec(struct ucred *cred, struct vnode *vp,
280 struct label *vplabel, struct image_params *imgp,
281 struct label *execlabel)
282 {
283
284 if (execlabel != NULL) {
285 /*
286 * We currently don't permit labels to be changed at
287 * exec-time as part of the partition model, so disallow
288 * non-NULL partition label changes in execlabel.
289 */
290 if (SLOT(execlabel) != 0)
291 return (EINVAL);
292 }
293
294 return (0);
295 }
296
297 static struct mac_policy_ops partition_ops =
298 {
299 .mpo_cred_check_relabel = partition_cred_check_relabel,
300 .mpo_cred_check_visible = partition_cred_check_visible,
301 .mpo_cred_copy_label = partition_cred_copy_label,
302 .mpo_cred_create_init = partition_cred_create_init,
303 .mpo_cred_create_swapper = partition_cred_create_swapper,
304 .mpo_cred_destroy_label = partition_cred_destroy_label,
305 .mpo_cred_externalize_label = partition_cred_externalize_label,
306 .mpo_cred_init_label = partition_cred_init_label,
307 .mpo_cred_internalize_label = partition_cred_internalize_label,
308 .mpo_cred_relabel = partition_cred_relabel,
309 .mpo_inpcb_check_visible = partition_inpcb_check_visible,
310 .mpo_proc_check_debug = partition_proc_check_debug,
311 .mpo_proc_check_sched = partition_proc_check_sched,
312 .mpo_proc_check_signal = partition_proc_check_signal,
313 .mpo_socket_check_visible = partition_socket_check_visible,
314 .mpo_vnode_check_exec = partition_vnode_check_exec,
315 };
316
317 MAC_POLICY_SET(&partition_ops, mac_partition, "TrustedBSD MAC/Partition",
318 MPC_LOADTIME_FLAG_UNLOADOK, &partition_slot);
319