1 /*-
2 * Copyright (c) 1999-2002, 2009, 2019 Robert N. M. Watson
3 * Copyright (c) 2001 Ilmar S. Habibulin
4 * Copyright (c) 2001-2004 Networks Associates Technology, Inc.
5 * Copyright (c) 2006 SPARTA, Inc.
6 * Copyright (c) 2008 Apple Inc.
7 * All rights reserved.
8 *
9 * This software was developed by Robert Watson and Ilmar Habibulin for the
10 * TrustedBSD Project.
11 *
12 * This software was enhanced by SPARTA ISSO under SPAWAR contract
13 * N66001-04-C-6019 ("SEFOS").
14 *
15 * This software was developed for the FreeBSD Project in part by Network
16 * Associates Laboratories, the Security Research Division of Network
17 * Associates, Inc. under DARPA/SPAWAR contract N66001-01-C-8035 ("CBOSS"),
18 * as part of the DARPA CHATS research program.
19 *
20 * This software was developed at the University of Cambridge Computer
21 * Laboratory with support from a grant from Google, Inc.
22 *
23 * Redistribution and use in source and binary forms, with or without
24 * modification, are permitted provided that the following conditions
25 * are met:
26 * 1. Redistributions of source code must retain the above copyright
27 * notice, this list of conditions and the following disclaimer.
28 * 2. Redistributions in binary form must reproduce the above copyright
29 * notice, this list of conditions and the following disclaimer in the
30 * documentation and/or other materials provided with the distribution.
31 *
32 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
33 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
34 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
35 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
36 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
37 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
38 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
39 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
40 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
41 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
42 * SUCH DAMAGE.
43 */
44
45 #include <sys/cdefs.h>
46 #include "opt_mac.h"
47
48 #include <sys/param.h>
49 #include <sys/kernel.h>
50 #include <sys/lock.h>
51 #include <sys/malloc.h>
52 #include <sys/mutex.h>
53 #include <sys/mac.h>
54 #include <sys/priv.h>
55 #include <sys/sbuf.h>
56 #include <sys/sdt.h>
57 #include <sys/systm.h>
58 #include <sys/mount.h>
59 #include <sys/file.h>
60 #include <sys/namei.h>
61 #include <sys/protosw.h>
62 #include <sys/socket.h>
63 #include <sys/socketvar.h>
64 #include <sys/sysctl.h>
65
66 #include <net/bpfdesc.h>
67 #include <net/if.h>
68 #include <net/if_var.h>
69
70 #include <security/mac/mac_framework.h>
71 #include <security/mac/mac_internal.h>
72 #include <security/mac/mac_policy.h>
73
74 /*
75 * XXXRW: struct ifnet locking is incomplete in the network code, so we use
76 * our own global mutex for struct ifnet. Non-ideal, but should help in the
77 * SMP environment.
78 *
79 * This lock is acquired only if a loaded policy is using ifnet labeling.
80 * This should not ever change during a MAC policy check, itself, but could
81 * change during setup/return from a check, so we have to condition unlock on
82 * previous lock.
83 */
84 struct mtx mac_ifnet_mtx;
85 MTX_SYSINIT(mac_ifnet_mtx, &mac_ifnet_mtx, "mac_ifnet", MTX_DEF);
86
87 /*
88 * Retrieve the label associated with an mbuf by searching for the tag.
89 * Depending on the value of mac_labelmbufs, it's possible that a label will
90 * not be present, in which case NULL is returned. Policies must handle the
91 * possibility of an mbuf not having label storage if they do not enforce
92 * early loading.
93 */
94 struct label *
mac_mbuf_to_label(struct mbuf * m)95 mac_mbuf_to_label(struct mbuf *m)
96 {
97 struct m_tag *tag;
98 struct label *label;
99
100 if (m == NULL)
101 return (NULL);
102 tag = m_tag_find(m, PACKET_TAG_MACLABEL, NULL);
103 if (tag == NULL)
104 return (NULL);
105 label = (struct label *)(tag+1);
106 return (label);
107 }
108
109 static struct label *
mac_bpfdesc_label_alloc(void)110 mac_bpfdesc_label_alloc(void)
111 {
112 struct label *label;
113
114 label = mac_labelzone_alloc(M_WAITOK);
115 MAC_POLICY_PERFORM(bpfdesc_init_label, label);
116 return (label);
117 }
118
119 void
mac_bpfdesc_init(struct bpf_d * d)120 mac_bpfdesc_init(struct bpf_d *d)
121 {
122
123 if (mac_labeled & MPC_OBJECT_BPFDESC)
124 d->bd_label = mac_bpfdesc_label_alloc();
125 else
126 d->bd_label = NULL;
127 }
128
129 static struct label *
mac_ifnet_label_alloc(void)130 mac_ifnet_label_alloc(void)
131 {
132 struct label *label;
133
134 label = mac_labelzone_alloc(M_WAITOK);
135 MAC_POLICY_PERFORM(ifnet_init_label, label);
136 return (label);
137 }
138
139 void
mac_ifnet_init(struct ifnet * ifp)140 mac_ifnet_init(struct ifnet *ifp)
141 {
142
143 if (mac_labeled & MPC_OBJECT_IFNET)
144 if_setmaclabel(ifp, mac_ifnet_label_alloc());
145 else
146 if_setmaclabel(ifp, NULL);
147 }
148
149 int
mac_mbuf_tag_init(struct m_tag * tag,int flag)150 mac_mbuf_tag_init(struct m_tag *tag, int flag)
151 {
152 struct label *label;
153 int error;
154
155 label = (struct label *) (tag + 1);
156 mac_init_label(label);
157
158 if (flag & M_WAITOK)
159 MAC_POLICY_CHECK(mbuf_init_label, label, flag);
160 else
161 MAC_POLICY_CHECK_NOSLEEP(mbuf_init_label, label, flag);
162 if (error) {
163 MAC_POLICY_PERFORM_NOSLEEP(mbuf_destroy_label, label);
164 mac_destroy_label(label);
165 }
166 return (error);
167 }
168
169 int
mac_mbuf_init(struct mbuf * m,int flag)170 mac_mbuf_init(struct mbuf *m, int flag)
171 {
172 struct m_tag *tag;
173 int error;
174
175 M_ASSERTPKTHDR(m);
176
177 if (mac_labeled & MPC_OBJECT_MBUF) {
178 tag = m_tag_get(PACKET_TAG_MACLABEL, sizeof(struct label),
179 flag);
180 if (tag == NULL)
181 return (ENOMEM);
182 error = mac_mbuf_tag_init(tag, flag);
183 if (error) {
184 m_tag_free(tag);
185 return (error);
186 }
187 m_tag_prepend(m, tag);
188 }
189 return (0);
190 }
191
192 static void
mac_bpfdesc_label_free(struct label * label)193 mac_bpfdesc_label_free(struct label *label)
194 {
195
196 MAC_POLICY_PERFORM_NOSLEEP(bpfdesc_destroy_label, label);
197 mac_labelzone_free(label);
198 }
199
200 void
mac_bpfdesc_destroy(struct bpf_d * d)201 mac_bpfdesc_destroy(struct bpf_d *d)
202 {
203
204 if (d->bd_label != NULL) {
205 mac_bpfdesc_label_free(d->bd_label);
206 d->bd_label = NULL;
207 }
208 }
209
210 static void
mac_ifnet_label_free(struct label * label)211 mac_ifnet_label_free(struct label *label)
212 {
213
214 MAC_POLICY_PERFORM_NOSLEEP(ifnet_destroy_label, label);
215 mac_labelzone_free(label);
216 }
217
218 void
mac_ifnet_destroy(struct ifnet * ifp)219 mac_ifnet_destroy(struct ifnet *ifp)
220 {
221 struct label *label = if_getmaclabel(ifp);
222 if (label != NULL) {
223 mac_ifnet_label_free(label);
224 if_setmaclabel(ifp, NULL);
225 }
226 }
227
228 void
mac_mbuf_tag_destroy(struct m_tag * tag)229 mac_mbuf_tag_destroy(struct m_tag *tag)
230 {
231 struct label *label;
232
233 label = (struct label *)(tag+1);
234
235 MAC_POLICY_PERFORM_NOSLEEP(mbuf_destroy_label, label);
236 mac_destroy_label(label);
237 }
238
239 /*
240 * mac_mbuf_tag_copy is called when an mbuf header is duplicated, in which
241 * case the labels must also be duplicated.
242 */
243 void
mac_mbuf_tag_copy(struct m_tag * src,struct m_tag * dest)244 mac_mbuf_tag_copy(struct m_tag *src, struct m_tag *dest)
245 {
246 struct label *src_label, *dest_label;
247
248 src_label = (struct label *)(src+1);
249 dest_label = (struct label *)(dest+1);
250
251 /*
252 * mac_mbuf_tag_init() is called on the target tag in m_tag_copy(),
253 * so we don't need to call it here.
254 */
255 MAC_POLICY_PERFORM_NOSLEEP(mbuf_copy_label, src_label, dest_label);
256 }
257
258 void
mac_mbuf_copy(struct mbuf * m_from,struct mbuf * m_to)259 mac_mbuf_copy(struct mbuf *m_from, struct mbuf *m_to)
260 {
261 struct label *src_label, *dest_label;
262
263 if (mac_policy_count == 0)
264 return;
265
266 src_label = mac_mbuf_to_label(m_from);
267 dest_label = mac_mbuf_to_label(m_to);
268
269 MAC_POLICY_PERFORM_NOSLEEP(mbuf_copy_label, src_label, dest_label);
270 }
271
272 static void
mac_ifnet_copy_label(struct label * src,struct label * dest)273 mac_ifnet_copy_label(struct label *src, struct label *dest)
274 {
275
276 MAC_POLICY_PERFORM_NOSLEEP(ifnet_copy_label, src, dest);
277 }
278
279 static int
mac_ifnet_externalize_label(struct label * label,char * elements,char * outbuf,size_t outbuflen)280 mac_ifnet_externalize_label(struct label *label, char *elements,
281 char *outbuf, size_t outbuflen)
282 {
283 int error;
284
285 MAC_POLICY_EXTERNALIZE(ifnet, label, elements, outbuf, outbuflen);
286
287 return (error);
288 }
289
290 static int
mac_ifnet_internalize_label(struct label * label,char * string)291 mac_ifnet_internalize_label(struct label *label, char *string)
292 {
293 int error;
294
295 MAC_POLICY_INTERNALIZE(ifnet, label, string);
296
297 return (error);
298 }
299
300 void
mac_ifnet_create(struct ifnet * ifp)301 mac_ifnet_create(struct ifnet *ifp)
302 {
303 int locked;
304
305 if (mac_policy_count == 0)
306 return;
307
308 MAC_IFNET_LOCK(ifp, locked);
309 MAC_POLICY_PERFORM_NOSLEEP(ifnet_create, ifp, if_getmaclabel(ifp));
310 MAC_IFNET_UNLOCK(ifp, locked);
311 }
312
313 void
mac_bpfdesc_create(struct ucred * cred,struct bpf_d * d)314 mac_bpfdesc_create(struct ucred *cred, struct bpf_d *d)
315 {
316
317 MAC_POLICY_PERFORM_NOSLEEP(bpfdesc_create, cred, d, d->bd_label);
318 }
319
320 void
mac_bpfdesc_create_mbuf(struct bpf_d * d,struct mbuf * m)321 mac_bpfdesc_create_mbuf(struct bpf_d *d, struct mbuf *m)
322 {
323 struct label *label;
324
325 /* Assume reader lock is enough. */
326 BPFD_LOCK_ASSERT(d);
327
328 if (mac_policy_count == 0)
329 return;
330
331 label = mac_mbuf_to_label(m);
332
333 MAC_POLICY_PERFORM_NOSLEEP(bpfdesc_create_mbuf, d, d->bd_label, m,
334 label);
335 }
336
337 void
mac_ifnet_create_mbuf_impl(struct ifnet * ifp,struct mbuf * m)338 mac_ifnet_create_mbuf_impl(struct ifnet *ifp, struct mbuf *m)
339 {
340 struct label *label;
341 int locked;
342
343 label = mac_mbuf_to_label(m);
344
345 MAC_IFNET_LOCK(ifp, locked);
346 MAC_POLICY_PERFORM_NOSLEEP(ifnet_create_mbuf, ifp, if_getmaclabel(ifp), m,
347 label);
348 MAC_IFNET_UNLOCK(ifp, locked);
349 }
350
351 MAC_CHECK_PROBE_DEFINE2(bpfdesc_check_receive, "struct bpf_d *",
352 "struct ifnet *");
353
354 int
mac_bpfdesc_check_receive(struct bpf_d * d,struct ifnet * ifp)355 mac_bpfdesc_check_receive(struct bpf_d *d, struct ifnet *ifp)
356 {
357 int error, locked;
358
359 /* Assume reader lock is enough. */
360 BPFD_LOCK_ASSERT(d);
361
362 if (mac_policy_count == 0)
363 return (0);
364
365 MAC_IFNET_LOCK(ifp, locked);
366 MAC_POLICY_CHECK_NOSLEEP(bpfdesc_check_receive, d, d->bd_label, ifp,
367 if_getmaclabel(ifp));
368 MAC_CHECK_PROBE2(bpfdesc_check_receive, error, d, ifp);
369 MAC_IFNET_UNLOCK(ifp, locked);
370
371 return (error);
372 }
373
374 MAC_CHECK_PROBE_DEFINE2(ifnet_check_transmit, "struct ifnet *",
375 "struct mbuf *");
376
377 int
mac_ifnet_check_transmit_impl(struct ifnet * ifp,struct mbuf * m)378 mac_ifnet_check_transmit_impl(struct ifnet *ifp, struct mbuf *m)
379 {
380 struct label *label;
381 int error, locked;
382
383 M_ASSERTPKTHDR(m);
384
385 label = mac_mbuf_to_label(m);
386
387 MAC_IFNET_LOCK(ifp, locked);
388 MAC_POLICY_CHECK_NOSLEEP(ifnet_check_transmit, ifp, if_getmaclabel(ifp), m,
389 label);
390 MAC_CHECK_PROBE2(ifnet_check_transmit, error, ifp, m);
391 MAC_IFNET_UNLOCK(ifp, locked);
392
393 return (error);
394 }
395
396 int
mac_ifnet_ioctl_get(struct ucred * cred,struct ifreq * ifr,struct ifnet * ifp)397 mac_ifnet_ioctl_get(struct ucred *cred, struct ifreq *ifr,
398 struct ifnet *ifp)
399 {
400 char *elements, *buffer;
401 struct label *intlabel;
402 struct mac mac;
403 int error, locked;
404
405 if (!(mac_labeled & MPC_OBJECT_IFNET))
406 return (EINVAL);
407
408 error = copyin(ifr_data_get_ptr(ifr), &mac, sizeof(mac));
409 if (error)
410 return (error);
411
412 error = mac_check_structmac_consistent(&mac);
413 if (error)
414 return (error);
415
416 elements = malloc(mac.m_buflen, M_MACTEMP, M_WAITOK);
417 error = copyinstr(mac.m_string, elements, mac.m_buflen, NULL);
418 if (error) {
419 free(elements, M_MACTEMP);
420 return (error);
421 }
422
423 buffer = malloc(mac.m_buflen, M_MACTEMP, M_WAITOK | M_ZERO);
424 intlabel = mac_ifnet_label_alloc();
425 MAC_IFNET_LOCK(ifp, locked);
426 mac_ifnet_copy_label(if_getmaclabel(ifp), intlabel);
427 MAC_IFNET_UNLOCK(ifp, locked);
428 error = mac_ifnet_externalize_label(intlabel, elements, buffer,
429 mac.m_buflen);
430 mac_ifnet_label_free(intlabel);
431 if (error == 0)
432 error = copyout(buffer, mac.m_string, strlen(buffer)+1);
433
434 free(buffer, M_MACTEMP);
435 free(elements, M_MACTEMP);
436
437 return (error);
438 }
439
440 int
mac_ifnet_ioctl_set(struct ucred * cred,struct ifreq * ifr,struct ifnet * ifp)441 mac_ifnet_ioctl_set(struct ucred *cred, struct ifreq *ifr, struct ifnet *ifp)
442 {
443 struct label *intlabel;
444 struct mac mac;
445 char *buffer;
446 int error, locked;
447
448 if (!(mac_labeled & MPC_OBJECT_IFNET))
449 return (EINVAL);
450
451 error = copyin(ifr_data_get_ptr(ifr), &mac, sizeof(mac));
452 if (error)
453 return (error);
454
455 error = mac_check_structmac_consistent(&mac);
456 if (error)
457 return (error);
458
459 buffer = malloc(mac.m_buflen, M_MACTEMP, M_WAITOK);
460 error = copyinstr(mac.m_string, buffer, mac.m_buflen, NULL);
461 if (error) {
462 free(buffer, M_MACTEMP);
463 return (error);
464 }
465
466 intlabel = mac_ifnet_label_alloc();
467 error = mac_ifnet_internalize_label(intlabel, buffer);
468 free(buffer, M_MACTEMP);
469 if (error) {
470 mac_ifnet_label_free(intlabel);
471 return (error);
472 }
473
474 /*
475 * XXX: Note that this is a redundant privilege check, since policies
476 * impose this check themselves if required by the policy
477 * Eventually, this should go away.
478 */
479 error = priv_check_cred(cred, PRIV_NET_SETIFMAC);
480 if (error) {
481 mac_ifnet_label_free(intlabel);
482 return (error);
483 }
484
485 MAC_IFNET_LOCK(ifp, locked);
486 MAC_POLICY_CHECK_NOSLEEP(ifnet_check_relabel, cred, ifp,
487 if_getmaclabel(ifp), intlabel);
488 if (error) {
489 MAC_IFNET_UNLOCK(ifp, locked);
490 mac_ifnet_label_free(intlabel);
491 return (error);
492 }
493
494 MAC_POLICY_PERFORM_NOSLEEP(ifnet_relabel, cred, ifp, if_getmaclabel(ifp),
495 intlabel);
496 MAC_IFNET_UNLOCK(ifp, locked);
497
498 mac_ifnet_label_free(intlabel);
499 return (0);
500 }
501