xref: /freebsd/sys/security/mac/mac_net.c (revision cc426dd31990b8b50b210efc450e404596548ca1)
1 /*-
2  * Copyright (c) 1999-2002, 2009 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 __FBSDID("$FreeBSD$");
47 
48 #include "opt_mac.h"
49 
50 #include <sys/param.h>
51 #include <sys/kernel.h>
52 #include <sys/lock.h>
53 #include <sys/malloc.h>
54 #include <sys/mutex.h>
55 #include <sys/mac.h>
56 #include <sys/priv.h>
57 #include <sys/sbuf.h>
58 #include <sys/sdt.h>
59 #include <sys/systm.h>
60 #include <sys/mount.h>
61 #include <sys/file.h>
62 #include <sys/namei.h>
63 #include <sys/protosw.h>
64 #include <sys/socket.h>
65 #include <sys/socketvar.h>
66 #include <sys/sysctl.h>
67 
68 #include <net/bpfdesc.h>
69 #include <net/if.h>
70 #include <net/if_var.h>
71 
72 #include <security/mac/mac_framework.h>
73 #include <security/mac/mac_internal.h>
74 #include <security/mac/mac_policy.h>
75 
76 /*
77  * XXXRW: struct ifnet locking is incomplete in the network code, so we use
78  * our own global mutex for struct ifnet.  Non-ideal, but should help in the
79  * SMP environment.
80  */
81 struct mtx mac_ifnet_mtx;
82 MTX_SYSINIT(mac_ifnet_mtx, &mac_ifnet_mtx, "mac_ifnet", MTX_DEF);
83 
84 /*
85  * Retrieve the label associated with an mbuf by searching for the tag.
86  * Depending on the value of mac_labelmbufs, it's possible that a label will
87  * not be present, in which case NULL is returned.  Policies must handle the
88  * possibility of an mbuf not having label storage if they do not enforce
89  * early loading.
90  */
91 struct label *
92 mac_mbuf_to_label(struct mbuf *m)
93 {
94 	struct m_tag *tag;
95 	struct label *label;
96 
97 	if (m == NULL)
98 		return (NULL);
99 	tag = m_tag_find(m, PACKET_TAG_MACLABEL, NULL);
100 	if (tag == NULL)
101 		return (NULL);
102 	label = (struct label *)(tag+1);
103 	return (label);
104 }
105 
106 static struct label *
107 mac_bpfdesc_label_alloc(void)
108 {
109 	struct label *label;
110 
111 	label = mac_labelzone_alloc(M_WAITOK);
112 	MAC_POLICY_PERFORM(bpfdesc_init_label, label);
113 	return (label);
114 }
115 
116 void
117 mac_bpfdesc_init(struct bpf_d *d)
118 {
119 
120 	if (mac_labeled & MPC_OBJECT_BPFDESC)
121 		d->bd_label = mac_bpfdesc_label_alloc();
122 	else
123 		d->bd_label = NULL;
124 }
125 
126 static struct label *
127 mac_ifnet_label_alloc(void)
128 {
129 	struct label *label;
130 
131 	label = mac_labelzone_alloc(M_WAITOK);
132 	MAC_POLICY_PERFORM(ifnet_init_label, label);
133 	return (label);
134 }
135 
136 void
137 mac_ifnet_init(struct ifnet *ifp)
138 {
139 
140 	if (mac_labeled & MPC_OBJECT_IFNET)
141 		ifp->if_label = mac_ifnet_label_alloc();
142 	else
143 		ifp->if_label = NULL;
144 }
145 
146 int
147 mac_mbuf_tag_init(struct m_tag *tag, int flag)
148 {
149 	struct label *label;
150 	int error;
151 
152 	label = (struct label *) (tag + 1);
153 	mac_init_label(label);
154 
155 	if (flag & M_WAITOK)
156 		MAC_POLICY_CHECK(mbuf_init_label, label, flag);
157 	else
158 		MAC_POLICY_CHECK_NOSLEEP(mbuf_init_label, label, flag);
159 	if (error) {
160 		MAC_POLICY_PERFORM_NOSLEEP(mbuf_destroy_label, label);
161 		mac_destroy_label(label);
162 	}
163 	return (error);
164 }
165 
166 int
167 mac_mbuf_init(struct mbuf *m, int flag)
168 {
169 	struct m_tag *tag;
170 	int error;
171 
172 	M_ASSERTPKTHDR(m);
173 
174 	if (mac_labeled & MPC_OBJECT_MBUF) {
175 		tag = m_tag_get(PACKET_TAG_MACLABEL, sizeof(struct label),
176 		    flag);
177 		if (tag == NULL)
178 			return (ENOMEM);
179 		error = mac_mbuf_tag_init(tag, flag);
180 		if (error) {
181 			m_tag_free(tag);
182 			return (error);
183 		}
184 		m_tag_prepend(m, tag);
185 	}
186 	return (0);
187 }
188 
189 static void
190 mac_bpfdesc_label_free(struct label *label)
191 {
192 
193 	MAC_POLICY_PERFORM_NOSLEEP(bpfdesc_destroy_label, label);
194 	mac_labelzone_free(label);
195 }
196 
197 void
198 mac_bpfdesc_destroy(struct bpf_d *d)
199 {
200 
201 	if (d->bd_label != NULL) {
202 		mac_bpfdesc_label_free(d->bd_label);
203 		d->bd_label = NULL;
204 	}
205 }
206 
207 static void
208 mac_ifnet_label_free(struct label *label)
209 {
210 
211 	MAC_POLICY_PERFORM_NOSLEEP(ifnet_destroy_label, label);
212 	mac_labelzone_free(label);
213 }
214 
215 void
216 mac_ifnet_destroy(struct ifnet *ifp)
217 {
218 
219 	if (ifp->if_label != NULL) {
220 		mac_ifnet_label_free(ifp->if_label);
221 		ifp->if_label = NULL;
222 	}
223 }
224 
225 void
226 mac_mbuf_tag_destroy(struct m_tag *tag)
227 {
228 	struct label *label;
229 
230 	label = (struct label *)(tag+1);
231 
232 	MAC_POLICY_PERFORM_NOSLEEP(mbuf_destroy_label, label);
233 	mac_destroy_label(label);
234 }
235 
236 /*
237  * mac_mbuf_tag_copy is called when an mbuf header is duplicated, in which
238  * case the labels must also be duplicated.
239  */
240 void
241 mac_mbuf_tag_copy(struct m_tag *src, struct m_tag *dest)
242 {
243 	struct label *src_label, *dest_label;
244 
245 	src_label = (struct label *)(src+1);
246 	dest_label = (struct label *)(dest+1);
247 
248 	/*
249 	 * mac_mbuf_tag_init() is called on the target tag in m_tag_copy(),
250 	 * so we don't need to call it here.
251 	 */
252 	MAC_POLICY_PERFORM_NOSLEEP(mbuf_copy_label, src_label, dest_label);
253 }
254 
255 void
256 mac_mbuf_copy(struct mbuf *m_from, struct mbuf *m_to)
257 {
258 	struct label *src_label, *dest_label;
259 
260 	if (mac_policy_count == 0)
261 		return;
262 
263 	src_label = mac_mbuf_to_label(m_from);
264 	dest_label = mac_mbuf_to_label(m_to);
265 
266 	MAC_POLICY_PERFORM_NOSLEEP(mbuf_copy_label, src_label, dest_label);
267 }
268 
269 static void
270 mac_ifnet_copy_label(struct label *src, struct label *dest)
271 {
272 
273 	MAC_POLICY_PERFORM_NOSLEEP(ifnet_copy_label, src, dest);
274 }
275 
276 static int
277 mac_ifnet_externalize_label(struct label *label, char *elements,
278     char *outbuf, size_t outbuflen)
279 {
280 	int error;
281 
282 	MAC_POLICY_EXTERNALIZE(ifnet, label, elements, outbuf, outbuflen);
283 
284 	return (error);
285 }
286 
287 static int
288 mac_ifnet_internalize_label(struct label *label, char *string)
289 {
290 	int error;
291 
292 	MAC_POLICY_INTERNALIZE(ifnet, label, string);
293 
294 	return (error);
295 }
296 
297 void
298 mac_ifnet_create(struct ifnet *ifp)
299 {
300 
301 	if (mac_policy_count == 0)
302 		return;
303 
304 	MAC_IFNET_LOCK(ifp);
305 	MAC_POLICY_PERFORM_NOSLEEP(ifnet_create, ifp, ifp->if_label);
306 	MAC_IFNET_UNLOCK(ifp);
307 }
308 
309 void
310 mac_bpfdesc_create(struct ucred *cred, struct bpf_d *d)
311 {
312 
313 	MAC_POLICY_PERFORM_NOSLEEP(bpfdesc_create, cred, d, d->bd_label);
314 }
315 
316 void
317 mac_bpfdesc_create_mbuf(struct bpf_d *d, struct mbuf *m)
318 {
319 	struct label *label;
320 
321 	/* Assume reader lock is enough. */
322 	BPFD_LOCK_ASSERT(d);
323 
324 	if (mac_policy_count == 0)
325 		return;
326 
327 	label = mac_mbuf_to_label(m);
328 
329 	MAC_POLICY_PERFORM_NOSLEEP(bpfdesc_create_mbuf, d, d->bd_label, m,
330 	    label);
331 }
332 
333 void
334 mac_ifnet_create_mbuf(struct ifnet *ifp, struct mbuf *m)
335 {
336 	struct label *label;
337 
338 	if (mac_policy_count == 0)
339 		return;
340 
341 	label = mac_mbuf_to_label(m);
342 
343 	MAC_IFNET_LOCK(ifp);
344 	MAC_POLICY_PERFORM_NOSLEEP(ifnet_create_mbuf, ifp, ifp->if_label, m,
345 	    label);
346 	MAC_IFNET_UNLOCK(ifp);
347 }
348 
349 MAC_CHECK_PROBE_DEFINE2(bpfdesc_check_receive, "struct bpf_d *",
350     "struct ifnet *");
351 
352 int
353 mac_bpfdesc_check_receive(struct bpf_d *d, struct ifnet *ifp)
354 {
355 	int error;
356 
357 	/* Assume reader lock is enough. */
358 	BPFD_LOCK_ASSERT(d);
359 
360 	if (mac_policy_count == 0)
361 		return (0);
362 
363 	MAC_IFNET_LOCK(ifp);
364 	MAC_POLICY_CHECK_NOSLEEP(bpfdesc_check_receive, d, d->bd_label, ifp,
365 	    ifp->if_label);
366 	MAC_CHECK_PROBE2(bpfdesc_check_receive, error, d, ifp);
367 	MAC_IFNET_UNLOCK(ifp);
368 
369 	return (error);
370 }
371 
372 MAC_CHECK_PROBE_DEFINE2(ifnet_check_transmit, "struct ifnet *",
373     "struct mbuf *");
374 
375 int
376 mac_ifnet_check_transmit(struct ifnet *ifp, struct mbuf *m)
377 {
378 	struct label *label;
379 	int error;
380 
381 	M_ASSERTPKTHDR(m);
382 
383 	if (mac_policy_count == 0)
384 		return (0);
385 
386 	label = mac_mbuf_to_label(m);
387 
388 	MAC_IFNET_LOCK(ifp);
389 	MAC_POLICY_CHECK_NOSLEEP(ifnet_check_transmit, ifp, ifp->if_label, m,
390 	    label);
391 	MAC_CHECK_PROBE2(ifnet_check_transmit, error, ifp, m);
392 	MAC_IFNET_UNLOCK(ifp);
393 
394 	return (error);
395 }
396 
397 int
398 mac_ifnet_ioctl_get(struct ucred *cred, struct ifreq *ifr,
399     struct ifnet *ifp)
400 {
401 	char *elements, *buffer;
402 	struct label *intlabel;
403 	struct mac mac;
404 	int error;
405 
406 	if (!(mac_labeled & MPC_OBJECT_IFNET))
407 		return (EINVAL);
408 
409 	error = copyin(ifr_data_get_ptr(ifr), &mac, sizeof(mac));
410 	if (error)
411 		return (error);
412 
413 	error = mac_check_structmac_consistent(&mac);
414 	if (error)
415 		return (error);
416 
417 	elements = malloc(mac.m_buflen, M_MACTEMP, M_WAITOK);
418 	error = copyinstr(mac.m_string, elements, mac.m_buflen, NULL);
419 	if (error) {
420 		free(elements, M_MACTEMP);
421 		return (error);
422 	}
423 
424 	buffer = malloc(mac.m_buflen, M_MACTEMP, M_WAITOK | M_ZERO);
425 	intlabel = mac_ifnet_label_alloc();
426 	MAC_IFNET_LOCK(ifp);
427 	mac_ifnet_copy_label(ifp->if_label, intlabel);
428 	MAC_IFNET_UNLOCK(ifp);
429 	error = mac_ifnet_externalize_label(intlabel, elements, buffer,
430 	    mac.m_buflen);
431 	mac_ifnet_label_free(intlabel);
432 	if (error == 0)
433 		error = copyout(buffer, mac.m_string, strlen(buffer)+1);
434 
435 	free(buffer, M_MACTEMP);
436 	free(elements, M_MACTEMP);
437 
438 	return (error);
439 }
440 
441 int
442 mac_ifnet_ioctl_set(struct ucred *cred, struct ifreq *ifr, struct ifnet *ifp)
443 {
444 	struct label *intlabel;
445 	struct mac mac;
446 	char *buffer;
447 	int error;
448 
449 	if (!(mac_labeled & MPC_OBJECT_IFNET))
450 		return (EINVAL);
451 
452 	error = copyin(ifr_data_get_ptr(ifr), &mac, sizeof(mac));
453 	if (error)
454 		return (error);
455 
456 	error = mac_check_structmac_consistent(&mac);
457 	if (error)
458 		return (error);
459 
460 	buffer = malloc(mac.m_buflen, M_MACTEMP, M_WAITOK);
461 	error = copyinstr(mac.m_string, buffer, mac.m_buflen, NULL);
462 	if (error) {
463 		free(buffer, M_MACTEMP);
464 		return (error);
465 	}
466 
467 	intlabel = mac_ifnet_label_alloc();
468 	error = mac_ifnet_internalize_label(intlabel, buffer);
469 	free(buffer, M_MACTEMP);
470 	if (error) {
471 		mac_ifnet_label_free(intlabel);
472 		return (error);
473 	}
474 
475 	/*
476 	 * XXX: Note that this is a redundant privilege check, since policies
477 	 * impose this check themselves if required by the policy
478 	 * Eventually, this should go away.
479 	 */
480 	error = priv_check_cred(cred, PRIV_NET_SETIFMAC);
481 	if (error) {
482 		mac_ifnet_label_free(intlabel);
483 		return (error);
484 	}
485 
486 	MAC_IFNET_LOCK(ifp);
487 	MAC_POLICY_CHECK_NOSLEEP(ifnet_check_relabel, cred, ifp,
488 	    ifp->if_label, intlabel);
489 	if (error) {
490 		MAC_IFNET_UNLOCK(ifp);
491 		mac_ifnet_label_free(intlabel);
492 		return (error);
493 	}
494 
495 	MAC_POLICY_PERFORM_NOSLEEP(ifnet_relabel, cred, ifp, ifp->if_label,
496 	    intlabel);
497 	MAC_IFNET_UNLOCK(ifp);
498 
499 	mac_ifnet_label_free(intlabel);
500 	return (0);
501 }
502