1/*-
2 * Copyright (c) 1999-2002, 2008 Robert N. M. Watson
3 * Copyright (c) 2001 Ilmar S. Habibulin
4 * Copyright (c) 2001-2003 Networks Associates Technology, Inc.
5 * Copyright (c) 2005 Samy Al Bahra
6 * Copyright (c) 2006 SPARTA, Inc.
7 * Copyright (c) 2008 Apple Inc.
8 * All rights reserved.
9 *
10 * This software was developed by Robert Watson and Ilmar Habibulin for the
11 * TrustedBSD Project.
12 *
13 * This software was developed for the FreeBSD Project in part by Network
14 * Associates Laboratories, the Security Research Division of Network
15 * Associates, Inc. under DARPA/SPAWAR contract N66001-01-C-8035 ("CBOSS"),
16 * as part of the DARPA CHATS research program.
17 *
18 * This software was enhanced by SPARTA ISSO under SPAWAR contract
19 * N66001-04-C-6019 ("SEFOS").
20 *
21 * Redistribution and use in source and binary forms, with or without
22 * modification, are permitted provided that the following conditions
23 * are met:
24 * 1. Redistributions of source code must retain the above copyright
25 * notice, this list of conditions and the following disclaimer.
26 * 2. Redistributions in binary form must reproduce the above copyright
27 * notice, this list of conditions and the following disclaimer in the
28 * documentation and/or other materials provided with the distribution.
29 *
30 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
31 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
32 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
33 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
34 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
35 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
36 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
37 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
38 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
39 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
40 * SUCH DAMAGE.
41 */
42
43#include <sys/cdefs.h>
44__FBSDID("$FreeBSD: head/sys/security/mac/mac_process.c 184407 2008-10-28 11:33:06Z rwatson $");
45
46#include "opt_mac.h"
47
48#include <sys/param.h>
49#include <sys/condvar.h>
50#include <sys/imgact.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/proc.h>
57#include <sys/sbuf.h>
58#include <sys/systm.h>
59#include <sys/vnode.h>
60#include <sys/mount.h>
61#include <sys/file.h>
62#include <sys/namei.h>
63#include <sys/sysctl.h>
64
65#include <vm/vm.h>
66#include <vm/pmap.h>
67#include <vm/vm_map.h>
68#include <vm/vm_object.h>
69
70#include <security/mac/mac_framework.h>
71#include <security/mac/mac_internal.h>
72#include <security/mac/mac_policy.h>
73
74static int mac_mmap_revocation = 1;
75SYSCTL_INT(_security_mac, OID_AUTO, mmap_revocation, CTLFLAG_RW,
76 &mac_mmap_revocation, 0, "Revoke mmap access to files on subject "
77 "relabel");
78
79static int mac_mmap_revocation_via_cow = 0;
80SYSCTL_INT(_security_mac, OID_AUTO, mmap_revocation_via_cow, CTLFLAG_RW,
81 &mac_mmap_revocation_via_cow, 0, "Revoke mmap access to files via "
82 "copy-on-write semantics, or by removing all write access");
83
84static void mac_cred_mmapped_drop_perms_recurse(struct thread *td,
85 struct ucred *cred, struct vm_map *map);
86
87struct label *
88mac_cred_label_alloc(void)
89{
90 struct label *label;
91
92 label = mac_labelzone_alloc(M_WAITOK);
93 MAC_PERFORM(cred_init_label, label);
94 return (label);
95}
96
97void
98mac_cred_init(struct ucred *cred)
99{
100
101 if (mac_labeled & MPC_OBJECT_CRED)
102 cred->cr_label = mac_cred_label_alloc();
103 else
104 cred->cr_label = NULL;
105}
106
107static struct label *
108mac_proc_label_alloc(void)
109{
110 struct label *label;
111
112 label = mac_labelzone_alloc(M_WAITOK);
113 MAC_PERFORM(proc_init_label, label);
114 return (label);
115}
116
117void
118mac_proc_init(struct proc *p)
119{
120
121 if (mac_labeled & MPC_OBJECT_PROC)
122 p->p_label = mac_proc_label_alloc();
123 else
124 p->p_label = NULL;
125}
126
127void
128mac_cred_label_free(struct label *label)
129{
130
131 MAC_PERFORM(cred_destroy_label, label);
132 mac_labelzone_free(label);
133}
134
135void
136mac_cred_destroy(struct ucred *cred)
137{
138
139 if (cred->cr_label != NULL) {
140 mac_cred_label_free(cred->cr_label);
141 cred->cr_label = NULL;
142 }
143}
144
145static void
146mac_proc_label_free(struct label *label)
147{
148
149 MAC_PERFORM(proc_destroy_label, label);
150 mac_labelzone_free(label);
151}
152
153void
154mac_proc_destroy(struct proc *p)
155{
156
157 if (p->p_label != NULL) {
158 mac_proc_label_free(p->p_label);
159 p->p_label = NULL;
160 }
161}
162
163/*
164 * When a thread becomes an NFS server daemon, its credential may need to be
165 * updated to reflect this so that policies can recognize when file system
166 * operations originate from the network.
167 *
168 * At some point, it would be desirable if the credential used for each NFS
169 * RPC could be set based on the RPC context (i.e., source system, etc) to
170 * provide more fine-grained access control.
171 */
172void
173mac_cred_associate_nfsd(struct ucred *cred)
174{
175
176 MAC_PERFORM(cred_associate_nfsd, cred);
177}
178
179/*
180 * Initialize MAC label for the first kernel process, from which other kernel
181 * processes and threads are spawned.
182 */
183void
184mac_cred_create_swapper(struct ucred *cred)
185{
186
187 MAC_PERFORM(cred_create_swapper, cred);
188}
189
190/*
191 * Initialize MAC label for the first userland process, from which other
192 * userland processes and threads are spawned.
193 */
194void
195mac_cred_create_init(struct ucred *cred)
196{
197
198 MAC_PERFORM(cred_create_init, cred);
199}
200
201int
202mac_cred_externalize_label(struct label *label, char *elements,
203 char *outbuf, size_t outbuflen)
204{
205 int error;
206
207 MAC_EXTERNALIZE(cred, label, elements, outbuf, outbuflen);
208
209 return (error);
210}
211
212int
213mac_cred_internalize_label(struct label *label, char *string)
214{
215 int error;
216
217 MAC_INTERNALIZE(cred, label, string);
218
219 return (error);
220}
221
222void
223mac_thread_userret(struct thread *td)
224{
225
226 MAC_PERFORM(thread_userret, td);
227}
228
229/*
230 * When a new process is created, its label must be initialized. Generally,
231 * this involves inheritence from the parent process, modulo possible deltas.
232 * This function allows that processing to take place.
233 */
234void
235mac_cred_copy(struct ucred *src, struct ucred *dest)
236{
237
238 MAC_PERFORM(cred_copy_label, src->cr_label, dest->cr_label);
239}
240
241int
242mac_execve_enter(struct image_params *imgp, struct mac *mac_p)
243{
244 struct label *label;
245 struct mac mac;
246 char *buffer;
247 int error;
248
249 if (mac_p == NULL)
250 return (0);
251
252 if (!(mac_labeled & MPC_OBJECT_CRED))
253 return (EINVAL);
254
255 error = copyin(mac_p, &mac, sizeof(mac));
256 if (error)
257 return (error);
258
259 error = mac_check_structmac_consistent(&mac);
260 if (error)
261 return (error);
262
263 buffer = malloc(mac.m_buflen, M_MACTEMP, M_WAITOK);
264 error = copyinstr(mac.m_string, buffer, mac.m_buflen, NULL);
265 if (error) {
266 free(buffer, M_MACTEMP);
267 return (error);
268 }
269
270 label = mac_cred_label_alloc();
271 error = mac_cred_internalize_label(label, buffer);
272 free(buffer, M_MACTEMP);
273 if (error) {
274 mac_cred_label_free(label);
275 return (error);
276 }
277 imgp->execlabel = label;
278 return (0);
279}
280
281void
282mac_execve_exit(struct image_params *imgp)
283{
284 if (imgp->execlabel != NULL) {
285 mac_cred_label_free(imgp->execlabel);
286 imgp->execlabel = NULL;
287 }
288}
289
290void
291mac_execve_interpreter_enter(struct vnode *interpvp,
292 struct label **interpvplabel)
293{
294
295 if (mac_labeled & MPC_OBJECT_VNODE) {
296 *interpvplabel = mac_vnode_label_alloc();
297 mac_vnode_copy_label(interpvp->v_label, *interpvplabel);
298 } else
299 *interpvplabel = NULL;
300}
301
302void
303mac_execve_interpreter_exit(struct label *interpvplabel)
304{
305
306 if (interpvplabel != NULL)
307 mac_vnode_label_free(interpvplabel);
308}
309
310/*
311 * When relabeling a process, call out to the policies for the maximum
312 * permission allowed for each object type we know about in its memory space,
313 * and revoke access (in the least surprising ways we know) when necessary.
314 * The process lock is not held here.
315 */
316void
317mac_cred_mmapped_drop_perms(struct thread *td, struct ucred *cred)
318{
319
320 /* XXX freeze all other threads */
321 mac_cred_mmapped_drop_perms_recurse(td, cred,
322 &td->td_proc->p_vmspace->vm_map);
323 /* XXX allow other threads to continue */
324}
325
326static __inline const char *
327prot2str(vm_prot_t prot)
328{
329
330 switch (prot & VM_PROT_ALL) {
331 case VM_PROT_READ:
332 return ("r--");
333 case VM_PROT_READ | VM_PROT_WRITE:
334 return ("rw-");
335 case VM_PROT_READ | VM_PROT_EXECUTE:
336 return ("r-x");
337 case VM_PROT_READ | VM_PROT_WRITE | VM_PROT_EXECUTE:
338 return ("rwx");
339 case VM_PROT_WRITE:
340 return ("-w-");
341 case VM_PROT_EXECUTE:
342 return ("--x");
343 case VM_PROT_WRITE | VM_PROT_EXECUTE:
344 return ("-wx");
345 default:
346 return ("---");
347 }
348}
349
350static void
351mac_cred_mmapped_drop_perms_recurse(struct thread *td, struct ucred *cred,
352 struct vm_map *map)
353{
354 struct vm_map_entry *vme;
355 int vfslocked, result;
356 vm_prot_t revokeperms;
357 vm_object_t backing_object, object;
358 vm_ooffset_t offset;
359 struct vnode *vp;
360 struct mount *mp;
361
362 if (!mac_mmap_revocation)
363 return;
364
365 vm_map_lock_read(map);
366 for (vme = map->header.next; vme != &map->header; vme = vme->next) {
367 if (vme->eflags & MAP_ENTRY_IS_SUB_MAP) {
368 mac_cred_mmapped_drop_perms_recurse(td, cred,
369 vme->object.sub_map);
370 continue;
371 }
372 /*
373 * Skip over entries that obviously are not shared.
374 */
375 if (vme->eflags & (MAP_ENTRY_COW | MAP_ENTRY_NOSYNC) ||
376 !vme->max_protection)
377 continue;
378 /*
379 * Drill down to the deepest backing object.
380 */
381 offset = vme->offset;
382 object = vme->object.vm_object;
383 if (object == NULL)
384 continue;
385 VM_OBJECT_LOCK(object);
386 while ((backing_object = object->backing_object) != NULL) {
387 VM_OBJECT_LOCK(backing_object);
388 offset += object->backing_object_offset;
389 VM_OBJECT_UNLOCK(object);
390 object = backing_object;
391 }
392 VM_OBJECT_UNLOCK(object);
393 /*
394 * At the moment, vm_maps and objects aren't considered by
395 * the MAC system, so only things with backing by a normal
396 * object (read: vnodes) are checked.
397 */
398 if (object->type != OBJT_VNODE)
399 continue;
400 vp = (struct vnode *)object->handle;
401 vfslocked = VFS_LOCK_GIANT(vp->v_mount);
402 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
403 result = vme->max_protection;
404 mac_vnode_check_mmap_downgrade(cred, vp, &result);
405 VOP_UNLOCK(vp, 0);
406 /*
407 * Find out what maximum protection we may be allowing now
408 * but a policy needs to get removed.
409 */
410 revokeperms = vme->max_protection & ~result;
411 if (!revokeperms) {
412 VFS_UNLOCK_GIANT(vfslocked);
413 continue;
414 }
415 printf("pid %ld: revoking %s perms from %#lx:%ld "
416 "(max %s/cur %s)\n", (long)td->td_proc->p_pid,
417 prot2str(revokeperms), (u_long)vme->start,
418 (long)(vme->end - vme->start),
419 prot2str(vme->max_protection), prot2str(vme->protection));
420 vm_map_lock_upgrade(map);
421 /*
422 * This is the really simple case: if a map has more
423 * max_protection than is allowed, but it's not being
424 * actually used (that is, the current protection is still
425 * allowed), we can just wipe it out and do nothing more.
426 */
427 if ((vme->protection & revokeperms) == 0) {
428 vme->max_protection -= revokeperms;
429 } else {
430 if (revokeperms & VM_PROT_WRITE) {
431 /*
432 * In the more complicated case, flush out all
433 * pending changes to the object then turn it
434 * copy-on-write.
435 */
436 vm_object_reference(object);
437 (void) vn_start_write(vp, &mp, V_WAIT);
438 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
439 VM_OBJECT_LOCK(object);
440 vm_object_page_clean(object,
441 OFF_TO_IDX(offset),
442 OFF_TO_IDX(offset + vme->end - vme->start +
443 PAGE_MASK),
444 OBJPC_SYNC);
445 VM_OBJECT_UNLOCK(object);
446 VOP_UNLOCK(vp, 0);
447 vn_finished_write(mp);
448 vm_object_deallocate(object);
449 /*
450 * Why bother if there's no read permissions
451 * anymore? For the rest, we need to leave
452 * the write permissions on for COW, or
453 * remove them entirely if configured to.
454 */
455 if (!mac_mmap_revocation_via_cow) {
456 vme->max_protection &= ~VM_PROT_WRITE;
457 vme->protection &= ~VM_PROT_WRITE;
458 } if ((revokeperms & VM_PROT_READ) == 0)
459 vme->eflags |= MAP_ENTRY_COW |
460 MAP_ENTRY_NEEDS_COPY;
461 }
462 if (revokeperms & VM_PROT_EXECUTE) {
463 vme->max_protection &= ~VM_PROT_EXECUTE;
464 vme->protection &= ~VM_PROT_EXECUTE;
465 }
466 if (revokeperms & VM_PROT_READ) {
467 vme->max_protection = 0;
468 vme->protection = 0;
469 }
470 pmap_protect(map->pmap, vme->start, vme->end,
471 vme->protection & ~revokeperms);
472 vm_map_simplify_entry(map, vme);
473 }
474 vm_map_lock_downgrade(map);
475 VFS_UNLOCK_GIANT(vfslocked);
476 }
477 vm_map_unlock_read(map);
478}
479
480/*
481 * When the subject's label changes, it may require revocation of privilege
482 * to mapped objects. This can't be done on-the-fly later with a unified
483 * buffer cache.
484 */
485void
486mac_cred_relabel(struct ucred *cred, struct label *newlabel)
487{
488
489 MAC_PERFORM(cred_relabel, cred, newlabel);
490}
491
492int
493mac_cred_check_relabel(struct ucred *cred, struct label *newlabel)
494{
495 int error;
496
497 MAC_CHECK(cred_check_relabel, cred, newlabel);
498
499 return (error);
500}
501
502int
503mac_cred_check_visible(struct ucred *cr1, struct ucred *cr2)
504{
505 int error;
506
507 MAC_CHECK(cred_check_visible, cr1, cr2);
508
509 return (error);
510}
511
512int
513mac_proc_check_debug(struct ucred *cred, struct proc *p)
514{
515 int error;
516
517 PROC_LOCK_ASSERT(p, MA_OWNED);
518
519 MAC_CHECK(proc_check_debug, cred, p);
520
521 return (error);
522}
523
524int
525mac_proc_check_sched(struct ucred *cred, struct proc *p)
526{
527 int error;
528
529 PROC_LOCK_ASSERT(p, MA_OWNED);
530
531 MAC_CHECK(proc_check_sched, cred, p);
532
533 return (error);
534}
535
536int
537mac_proc_check_signal(struct ucred *cred, struct proc *p, int signum)
538{
539 int error;
540
541 PROC_LOCK_ASSERT(p, MA_OWNED);
542
543 MAC_CHECK(proc_check_signal, cred, p, signum);
544
545 return (error);
546}
547
548int
549mac_proc_check_setuid(struct proc *p, struct ucred *cred, uid_t uid)
550{
551 int error;
552
553 PROC_LOCK_ASSERT(p, MA_OWNED);
554
555 MAC_CHECK(proc_check_setuid, cred, uid);
556 return (error);
557}
558
559int
560mac_proc_check_seteuid(struct proc *p, struct ucred *cred, uid_t euid)
561{
562 int error;
563
564 PROC_LOCK_ASSERT(p, MA_OWNED);
565
566 MAC_CHECK(proc_check_seteuid, cred, euid);
567 return (error);
568}
569
570int
571mac_proc_check_setgid(struct proc *p, struct ucred *cred, gid_t gid)
572{
573 int error;
574
575 PROC_LOCK_ASSERT(p, MA_OWNED);
576
577 MAC_CHECK(proc_check_setgid, cred, gid);
578
579 return (error);
580}
581
582int
583mac_proc_check_setegid(struct proc *p, struct ucred *cred, gid_t egid)
584{
585 int error;
586
587 PROC_LOCK_ASSERT(p, MA_OWNED);
588
589 MAC_CHECK(proc_check_setegid, cred, egid);
590
591 return (error);
592}
593
594int
595mac_proc_check_setgroups(struct proc *p, struct ucred *cred, int ngroups,
596 gid_t *gidset)
597{
598 int error;
599
600 PROC_LOCK_ASSERT(p, MA_OWNED);
601
602 MAC_CHECK(proc_check_setgroups, cred, ngroups, gidset);
603 return (error);
604}
605
606int
607mac_proc_check_setreuid(struct proc *p, struct ucred *cred, uid_t ruid,
608 uid_t euid)
609{
610 int error;
611
612 PROC_LOCK_ASSERT(p, MA_OWNED);
613
614 MAC_CHECK(proc_check_setreuid, cred, ruid, euid);
615
616 return (error);
617}
618
619int
620mac_proc_check_setregid(struct proc *proc, struct ucred *cred, gid_t rgid,
621 gid_t egid)
622{
623 int error;
624
625 PROC_LOCK_ASSERT(proc, MA_OWNED);
626
627 MAC_CHECK(proc_check_setregid, cred, rgid, egid);
628
629 return (error);
630}
631
632int
633mac_proc_check_setresuid(struct proc *p, struct ucred *cred, uid_t ruid,
634 uid_t euid, uid_t suid)
635{
636 int error;
637
638 PROC_LOCK_ASSERT(p, MA_OWNED);
639
640 MAC_CHECK(proc_check_setresuid, cred, ruid, euid, suid);
641 return (error);
642}
643
644int
645mac_proc_check_setresgid(struct proc *p, struct ucred *cred, gid_t rgid,
646 gid_t egid, gid_t sgid)
647{
648 int error;
649
650 PROC_LOCK_ASSERT(p, MA_OWNED);
651
652 MAC_CHECK(proc_check_setresgid, cred, rgid, egid, sgid);
653
654 return (error);
655}
656
657int
658mac_proc_check_wait(struct ucred *cred, struct proc *p)
659{
660 int error;
661
662 PROC_LOCK_ASSERT(p, MA_OWNED);
663
664 MAC_CHECK(proc_check_wait, cred, p);
665
666 return (error);
667}
2 * Copyright (c) 1999-2002, 2008 Robert N. M. Watson
3 * Copyright (c) 2001 Ilmar S. Habibulin
4 * Copyright (c) 2001-2003 Networks Associates Technology, Inc.
5 * Copyright (c) 2005 Samy Al Bahra
6 * Copyright (c) 2006 SPARTA, Inc.
7 * Copyright (c) 2008 Apple Inc.
8 * All rights reserved.
9 *
10 * This software was developed by Robert Watson and Ilmar Habibulin for the
11 * TrustedBSD Project.
12 *
13 * This software was developed for the FreeBSD Project in part by Network
14 * Associates Laboratories, the Security Research Division of Network
15 * Associates, Inc. under DARPA/SPAWAR contract N66001-01-C-8035 ("CBOSS"),
16 * as part of the DARPA CHATS research program.
17 *
18 * This software was enhanced by SPARTA ISSO under SPAWAR contract
19 * N66001-04-C-6019 ("SEFOS").
20 *
21 * Redistribution and use in source and binary forms, with or without
22 * modification, are permitted provided that the following conditions
23 * are met:
24 * 1. Redistributions of source code must retain the above copyright
25 * notice, this list of conditions and the following disclaimer.
26 * 2. Redistributions in binary form must reproduce the above copyright
27 * notice, this list of conditions and the following disclaimer in the
28 * documentation and/or other materials provided with the distribution.
29 *
30 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
31 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
32 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
33 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
34 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
35 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
36 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
37 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
38 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
39 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
40 * SUCH DAMAGE.
41 */
42
43#include <sys/cdefs.h>
44__FBSDID("$FreeBSD: head/sys/security/mac/mac_process.c 184407 2008-10-28 11:33:06Z rwatson $");
45
46#include "opt_mac.h"
47
48#include <sys/param.h>
49#include <sys/condvar.h>
50#include <sys/imgact.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/proc.h>
57#include <sys/sbuf.h>
58#include <sys/systm.h>
59#include <sys/vnode.h>
60#include <sys/mount.h>
61#include <sys/file.h>
62#include <sys/namei.h>
63#include <sys/sysctl.h>
64
65#include <vm/vm.h>
66#include <vm/pmap.h>
67#include <vm/vm_map.h>
68#include <vm/vm_object.h>
69
70#include <security/mac/mac_framework.h>
71#include <security/mac/mac_internal.h>
72#include <security/mac/mac_policy.h>
73
74static int mac_mmap_revocation = 1;
75SYSCTL_INT(_security_mac, OID_AUTO, mmap_revocation, CTLFLAG_RW,
76 &mac_mmap_revocation, 0, "Revoke mmap access to files on subject "
77 "relabel");
78
79static int mac_mmap_revocation_via_cow = 0;
80SYSCTL_INT(_security_mac, OID_AUTO, mmap_revocation_via_cow, CTLFLAG_RW,
81 &mac_mmap_revocation_via_cow, 0, "Revoke mmap access to files via "
82 "copy-on-write semantics, or by removing all write access");
83
84static void mac_cred_mmapped_drop_perms_recurse(struct thread *td,
85 struct ucred *cred, struct vm_map *map);
86
87struct label *
88mac_cred_label_alloc(void)
89{
90 struct label *label;
91
92 label = mac_labelzone_alloc(M_WAITOK);
93 MAC_PERFORM(cred_init_label, label);
94 return (label);
95}
96
97void
98mac_cred_init(struct ucred *cred)
99{
100
101 if (mac_labeled & MPC_OBJECT_CRED)
102 cred->cr_label = mac_cred_label_alloc();
103 else
104 cred->cr_label = NULL;
105}
106
107static struct label *
108mac_proc_label_alloc(void)
109{
110 struct label *label;
111
112 label = mac_labelzone_alloc(M_WAITOK);
113 MAC_PERFORM(proc_init_label, label);
114 return (label);
115}
116
117void
118mac_proc_init(struct proc *p)
119{
120
121 if (mac_labeled & MPC_OBJECT_PROC)
122 p->p_label = mac_proc_label_alloc();
123 else
124 p->p_label = NULL;
125}
126
127void
128mac_cred_label_free(struct label *label)
129{
130
131 MAC_PERFORM(cred_destroy_label, label);
132 mac_labelzone_free(label);
133}
134
135void
136mac_cred_destroy(struct ucred *cred)
137{
138
139 if (cred->cr_label != NULL) {
140 mac_cred_label_free(cred->cr_label);
141 cred->cr_label = NULL;
142 }
143}
144
145static void
146mac_proc_label_free(struct label *label)
147{
148
149 MAC_PERFORM(proc_destroy_label, label);
150 mac_labelzone_free(label);
151}
152
153void
154mac_proc_destroy(struct proc *p)
155{
156
157 if (p->p_label != NULL) {
158 mac_proc_label_free(p->p_label);
159 p->p_label = NULL;
160 }
161}
162
163/*
164 * When a thread becomes an NFS server daemon, its credential may need to be
165 * updated to reflect this so that policies can recognize when file system
166 * operations originate from the network.
167 *
168 * At some point, it would be desirable if the credential used for each NFS
169 * RPC could be set based on the RPC context (i.e., source system, etc) to
170 * provide more fine-grained access control.
171 */
172void
173mac_cred_associate_nfsd(struct ucred *cred)
174{
175
176 MAC_PERFORM(cred_associate_nfsd, cred);
177}
178
179/*
180 * Initialize MAC label for the first kernel process, from which other kernel
181 * processes and threads are spawned.
182 */
183void
184mac_cred_create_swapper(struct ucred *cred)
185{
186
187 MAC_PERFORM(cred_create_swapper, cred);
188}
189
190/*
191 * Initialize MAC label for the first userland process, from which other
192 * userland processes and threads are spawned.
193 */
194void
195mac_cred_create_init(struct ucred *cred)
196{
197
198 MAC_PERFORM(cred_create_init, cred);
199}
200
201int
202mac_cred_externalize_label(struct label *label, char *elements,
203 char *outbuf, size_t outbuflen)
204{
205 int error;
206
207 MAC_EXTERNALIZE(cred, label, elements, outbuf, outbuflen);
208
209 return (error);
210}
211
212int
213mac_cred_internalize_label(struct label *label, char *string)
214{
215 int error;
216
217 MAC_INTERNALIZE(cred, label, string);
218
219 return (error);
220}
221
222void
223mac_thread_userret(struct thread *td)
224{
225
226 MAC_PERFORM(thread_userret, td);
227}
228
229/*
230 * When a new process is created, its label must be initialized. Generally,
231 * this involves inheritence from the parent process, modulo possible deltas.
232 * This function allows that processing to take place.
233 */
234void
235mac_cred_copy(struct ucred *src, struct ucred *dest)
236{
237
238 MAC_PERFORM(cred_copy_label, src->cr_label, dest->cr_label);
239}
240
241int
242mac_execve_enter(struct image_params *imgp, struct mac *mac_p)
243{
244 struct label *label;
245 struct mac mac;
246 char *buffer;
247 int error;
248
249 if (mac_p == NULL)
250 return (0);
251
252 if (!(mac_labeled & MPC_OBJECT_CRED))
253 return (EINVAL);
254
255 error = copyin(mac_p, &mac, sizeof(mac));
256 if (error)
257 return (error);
258
259 error = mac_check_structmac_consistent(&mac);
260 if (error)
261 return (error);
262
263 buffer = malloc(mac.m_buflen, M_MACTEMP, M_WAITOK);
264 error = copyinstr(mac.m_string, buffer, mac.m_buflen, NULL);
265 if (error) {
266 free(buffer, M_MACTEMP);
267 return (error);
268 }
269
270 label = mac_cred_label_alloc();
271 error = mac_cred_internalize_label(label, buffer);
272 free(buffer, M_MACTEMP);
273 if (error) {
274 mac_cred_label_free(label);
275 return (error);
276 }
277 imgp->execlabel = label;
278 return (0);
279}
280
281void
282mac_execve_exit(struct image_params *imgp)
283{
284 if (imgp->execlabel != NULL) {
285 mac_cred_label_free(imgp->execlabel);
286 imgp->execlabel = NULL;
287 }
288}
289
290void
291mac_execve_interpreter_enter(struct vnode *interpvp,
292 struct label **interpvplabel)
293{
294
295 if (mac_labeled & MPC_OBJECT_VNODE) {
296 *interpvplabel = mac_vnode_label_alloc();
297 mac_vnode_copy_label(interpvp->v_label, *interpvplabel);
298 } else
299 *interpvplabel = NULL;
300}
301
302void
303mac_execve_interpreter_exit(struct label *interpvplabel)
304{
305
306 if (interpvplabel != NULL)
307 mac_vnode_label_free(interpvplabel);
308}
309
310/*
311 * When relabeling a process, call out to the policies for the maximum
312 * permission allowed for each object type we know about in its memory space,
313 * and revoke access (in the least surprising ways we know) when necessary.
314 * The process lock is not held here.
315 */
316void
317mac_cred_mmapped_drop_perms(struct thread *td, struct ucred *cred)
318{
319
320 /* XXX freeze all other threads */
321 mac_cred_mmapped_drop_perms_recurse(td, cred,
322 &td->td_proc->p_vmspace->vm_map);
323 /* XXX allow other threads to continue */
324}
325
326static __inline const char *
327prot2str(vm_prot_t prot)
328{
329
330 switch (prot & VM_PROT_ALL) {
331 case VM_PROT_READ:
332 return ("r--");
333 case VM_PROT_READ | VM_PROT_WRITE:
334 return ("rw-");
335 case VM_PROT_READ | VM_PROT_EXECUTE:
336 return ("r-x");
337 case VM_PROT_READ | VM_PROT_WRITE | VM_PROT_EXECUTE:
338 return ("rwx");
339 case VM_PROT_WRITE:
340 return ("-w-");
341 case VM_PROT_EXECUTE:
342 return ("--x");
343 case VM_PROT_WRITE | VM_PROT_EXECUTE:
344 return ("-wx");
345 default:
346 return ("---");
347 }
348}
349
350static void
351mac_cred_mmapped_drop_perms_recurse(struct thread *td, struct ucred *cred,
352 struct vm_map *map)
353{
354 struct vm_map_entry *vme;
355 int vfslocked, result;
356 vm_prot_t revokeperms;
357 vm_object_t backing_object, object;
358 vm_ooffset_t offset;
359 struct vnode *vp;
360 struct mount *mp;
361
362 if (!mac_mmap_revocation)
363 return;
364
365 vm_map_lock_read(map);
366 for (vme = map->header.next; vme != &map->header; vme = vme->next) {
367 if (vme->eflags & MAP_ENTRY_IS_SUB_MAP) {
368 mac_cred_mmapped_drop_perms_recurse(td, cred,
369 vme->object.sub_map);
370 continue;
371 }
372 /*
373 * Skip over entries that obviously are not shared.
374 */
375 if (vme->eflags & (MAP_ENTRY_COW | MAP_ENTRY_NOSYNC) ||
376 !vme->max_protection)
377 continue;
378 /*
379 * Drill down to the deepest backing object.
380 */
381 offset = vme->offset;
382 object = vme->object.vm_object;
383 if (object == NULL)
384 continue;
385 VM_OBJECT_LOCK(object);
386 while ((backing_object = object->backing_object) != NULL) {
387 VM_OBJECT_LOCK(backing_object);
388 offset += object->backing_object_offset;
389 VM_OBJECT_UNLOCK(object);
390 object = backing_object;
391 }
392 VM_OBJECT_UNLOCK(object);
393 /*
394 * At the moment, vm_maps and objects aren't considered by
395 * the MAC system, so only things with backing by a normal
396 * object (read: vnodes) are checked.
397 */
398 if (object->type != OBJT_VNODE)
399 continue;
400 vp = (struct vnode *)object->handle;
401 vfslocked = VFS_LOCK_GIANT(vp->v_mount);
402 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
403 result = vme->max_protection;
404 mac_vnode_check_mmap_downgrade(cred, vp, &result);
405 VOP_UNLOCK(vp, 0);
406 /*
407 * Find out what maximum protection we may be allowing now
408 * but a policy needs to get removed.
409 */
410 revokeperms = vme->max_protection & ~result;
411 if (!revokeperms) {
412 VFS_UNLOCK_GIANT(vfslocked);
413 continue;
414 }
415 printf("pid %ld: revoking %s perms from %#lx:%ld "
416 "(max %s/cur %s)\n", (long)td->td_proc->p_pid,
417 prot2str(revokeperms), (u_long)vme->start,
418 (long)(vme->end - vme->start),
419 prot2str(vme->max_protection), prot2str(vme->protection));
420 vm_map_lock_upgrade(map);
421 /*
422 * This is the really simple case: if a map has more
423 * max_protection than is allowed, but it's not being
424 * actually used (that is, the current protection is still
425 * allowed), we can just wipe it out and do nothing more.
426 */
427 if ((vme->protection & revokeperms) == 0) {
428 vme->max_protection -= revokeperms;
429 } else {
430 if (revokeperms & VM_PROT_WRITE) {
431 /*
432 * In the more complicated case, flush out all
433 * pending changes to the object then turn it
434 * copy-on-write.
435 */
436 vm_object_reference(object);
437 (void) vn_start_write(vp, &mp, V_WAIT);
438 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
439 VM_OBJECT_LOCK(object);
440 vm_object_page_clean(object,
441 OFF_TO_IDX(offset),
442 OFF_TO_IDX(offset + vme->end - vme->start +
443 PAGE_MASK),
444 OBJPC_SYNC);
445 VM_OBJECT_UNLOCK(object);
446 VOP_UNLOCK(vp, 0);
447 vn_finished_write(mp);
448 vm_object_deallocate(object);
449 /*
450 * Why bother if there's no read permissions
451 * anymore? For the rest, we need to leave
452 * the write permissions on for COW, or
453 * remove them entirely if configured to.
454 */
455 if (!mac_mmap_revocation_via_cow) {
456 vme->max_protection &= ~VM_PROT_WRITE;
457 vme->protection &= ~VM_PROT_WRITE;
458 } if ((revokeperms & VM_PROT_READ) == 0)
459 vme->eflags |= MAP_ENTRY_COW |
460 MAP_ENTRY_NEEDS_COPY;
461 }
462 if (revokeperms & VM_PROT_EXECUTE) {
463 vme->max_protection &= ~VM_PROT_EXECUTE;
464 vme->protection &= ~VM_PROT_EXECUTE;
465 }
466 if (revokeperms & VM_PROT_READ) {
467 vme->max_protection = 0;
468 vme->protection = 0;
469 }
470 pmap_protect(map->pmap, vme->start, vme->end,
471 vme->protection & ~revokeperms);
472 vm_map_simplify_entry(map, vme);
473 }
474 vm_map_lock_downgrade(map);
475 VFS_UNLOCK_GIANT(vfslocked);
476 }
477 vm_map_unlock_read(map);
478}
479
480/*
481 * When the subject's label changes, it may require revocation of privilege
482 * to mapped objects. This can't be done on-the-fly later with a unified
483 * buffer cache.
484 */
485void
486mac_cred_relabel(struct ucred *cred, struct label *newlabel)
487{
488
489 MAC_PERFORM(cred_relabel, cred, newlabel);
490}
491
492int
493mac_cred_check_relabel(struct ucred *cred, struct label *newlabel)
494{
495 int error;
496
497 MAC_CHECK(cred_check_relabel, cred, newlabel);
498
499 return (error);
500}
501
502int
503mac_cred_check_visible(struct ucred *cr1, struct ucred *cr2)
504{
505 int error;
506
507 MAC_CHECK(cred_check_visible, cr1, cr2);
508
509 return (error);
510}
511
512int
513mac_proc_check_debug(struct ucred *cred, struct proc *p)
514{
515 int error;
516
517 PROC_LOCK_ASSERT(p, MA_OWNED);
518
519 MAC_CHECK(proc_check_debug, cred, p);
520
521 return (error);
522}
523
524int
525mac_proc_check_sched(struct ucred *cred, struct proc *p)
526{
527 int error;
528
529 PROC_LOCK_ASSERT(p, MA_OWNED);
530
531 MAC_CHECK(proc_check_sched, cred, p);
532
533 return (error);
534}
535
536int
537mac_proc_check_signal(struct ucred *cred, struct proc *p, int signum)
538{
539 int error;
540
541 PROC_LOCK_ASSERT(p, MA_OWNED);
542
543 MAC_CHECK(proc_check_signal, cred, p, signum);
544
545 return (error);
546}
547
548int
549mac_proc_check_setuid(struct proc *p, struct ucred *cred, uid_t uid)
550{
551 int error;
552
553 PROC_LOCK_ASSERT(p, MA_OWNED);
554
555 MAC_CHECK(proc_check_setuid, cred, uid);
556 return (error);
557}
558
559int
560mac_proc_check_seteuid(struct proc *p, struct ucred *cred, uid_t euid)
561{
562 int error;
563
564 PROC_LOCK_ASSERT(p, MA_OWNED);
565
566 MAC_CHECK(proc_check_seteuid, cred, euid);
567 return (error);
568}
569
570int
571mac_proc_check_setgid(struct proc *p, struct ucred *cred, gid_t gid)
572{
573 int error;
574
575 PROC_LOCK_ASSERT(p, MA_OWNED);
576
577 MAC_CHECK(proc_check_setgid, cred, gid);
578
579 return (error);
580}
581
582int
583mac_proc_check_setegid(struct proc *p, struct ucred *cred, gid_t egid)
584{
585 int error;
586
587 PROC_LOCK_ASSERT(p, MA_OWNED);
588
589 MAC_CHECK(proc_check_setegid, cred, egid);
590
591 return (error);
592}
593
594int
595mac_proc_check_setgroups(struct proc *p, struct ucred *cred, int ngroups,
596 gid_t *gidset)
597{
598 int error;
599
600 PROC_LOCK_ASSERT(p, MA_OWNED);
601
602 MAC_CHECK(proc_check_setgroups, cred, ngroups, gidset);
603 return (error);
604}
605
606int
607mac_proc_check_setreuid(struct proc *p, struct ucred *cred, uid_t ruid,
608 uid_t euid)
609{
610 int error;
611
612 PROC_LOCK_ASSERT(p, MA_OWNED);
613
614 MAC_CHECK(proc_check_setreuid, cred, ruid, euid);
615
616 return (error);
617}
618
619int
620mac_proc_check_setregid(struct proc *proc, struct ucred *cred, gid_t rgid,
621 gid_t egid)
622{
623 int error;
624
625 PROC_LOCK_ASSERT(proc, MA_OWNED);
626
627 MAC_CHECK(proc_check_setregid, cred, rgid, egid);
628
629 return (error);
630}
631
632int
633mac_proc_check_setresuid(struct proc *p, struct ucred *cred, uid_t ruid,
634 uid_t euid, uid_t suid)
635{
636 int error;
637
638 PROC_LOCK_ASSERT(p, MA_OWNED);
639
640 MAC_CHECK(proc_check_setresuid, cred, ruid, euid, suid);
641 return (error);
642}
643
644int
645mac_proc_check_setresgid(struct proc *p, struct ucred *cred, gid_t rgid,
646 gid_t egid, gid_t sgid)
647{
648 int error;
649
650 PROC_LOCK_ASSERT(p, MA_OWNED);
651
652 MAC_CHECK(proc_check_setresgid, cred, rgid, egid, sgid);
653
654 return (error);
655}
656
657int
658mac_proc_check_wait(struct ucred *cred, struct proc *p)
659{
660 int error;
661
662 PROC_LOCK_ASSERT(p, MA_OWNED);
663
664 MAC_CHECK(proc_check_wait, cred, p);
665
666 return (error);
667}