xref: /freebsd/sys/security/mac/mac_syscalls.c (revision e8d8bef961a50d4dc22501cde4fb9fb0be1b2532)
1 /*-
2  * Copyright (c) 1999-2002, 2006, 2009 Robert N. M. Watson
3  * Copyright (c) 2001 Ilmar S. Habibulin
4  * Copyright (c) 2001-2005 Networks Associates Technology, Inc.
5  * Copyright (c) 2005-2006 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 developed for the FreeBSD Project in part by Network
13  * Associates Laboratories, the Security Research Division of Network
14  * Associates, Inc. under DARPA/SPAWAR contract N66001-01-C-8035 ("CBOSS"),
15  * as part of the DARPA CHATS research program.
16  *
17  * This software was enhanced by SPARTA ISSO under SPAWAR contract
18  * N66001-04-C-6019 ("SEFOS").
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/capsicum.h>
52 #include <sys/fcntl.h>
53 #include <sys/kernel.h>
54 #include <sys/lock.h>
55 #include <sys/malloc.h>
56 #include <sys/mutex.h>
57 #include <sys/mac.h>
58 #include <sys/proc.h>
59 #include <sys/systm.h>
60 #include <sys/sysctl.h>
61 #include <sys/sysproto.h>
62 #include <sys/sysent.h>
63 #include <sys/vnode.h>
64 #include <sys/mount.h>
65 #include <sys/file.h>
66 #include <sys/namei.h>
67 #include <sys/socket.h>
68 #include <sys/pipe.h>
69 #include <sys/socketvar.h>
70 
71 #include <security/mac/mac_framework.h>
72 #include <security/mac/mac_internal.h>
73 #include <security/mac/mac_policy.h>
74 
75 #ifdef MAC
76 
77 FEATURE(security_mac, "Mandatory Access Control Framework support");
78 
79 static int	kern___mac_get_path(struct thread *td, const char *path_p,
80 		    struct mac *mac_p, int follow);
81 static int	kern___mac_set_path(struct thread *td, const char *path_p,
82 		    struct mac *mac_p, int follow);
83 
84 int
85 sys___mac_get_pid(struct thread *td, struct __mac_get_pid_args *uap)
86 {
87 	char *elements, *buffer;
88 	struct mac mac;
89 	struct proc *tproc;
90 	struct ucred *tcred;
91 	int error;
92 
93 	error = copyin(uap->mac_p, &mac, sizeof(mac));
94 	if (error)
95 		return (error);
96 
97 	error = mac_check_structmac_consistent(&mac);
98 	if (error)
99 		return (error);
100 
101 	tproc = pfind(uap->pid);
102 	if (tproc == NULL)
103 		return (ESRCH);
104 
105 	tcred = NULL;				/* Satisfy gcc. */
106 	error = p_cansee(td, tproc);
107 	if (error == 0)
108 		tcred = crhold(tproc->p_ucred);
109 	PROC_UNLOCK(tproc);
110 	if (error)
111 		return (error);
112 
113 	elements = malloc(mac.m_buflen, M_MACTEMP, M_WAITOK);
114 	error = copyinstr(mac.m_string, elements, mac.m_buflen, NULL);
115 	if (error) {
116 		free(elements, M_MACTEMP);
117 		crfree(tcred);
118 		return (error);
119 	}
120 
121 	buffer = malloc(mac.m_buflen, M_MACTEMP, M_WAITOK | M_ZERO);
122 	error = mac_cred_externalize_label(tcred->cr_label, elements,
123 	    buffer, mac.m_buflen);
124 	if (error == 0)
125 		error = copyout(buffer, mac.m_string, strlen(buffer)+1);
126 
127 	free(buffer, M_MACTEMP);
128 	free(elements, M_MACTEMP);
129 	crfree(tcred);
130 	return (error);
131 }
132 
133 int
134 sys___mac_get_proc(struct thread *td, struct __mac_get_proc_args *uap)
135 {
136 	char *elements, *buffer;
137 	struct mac mac;
138 	int error;
139 
140 	error = copyin(uap->mac_p, &mac, sizeof(mac));
141 	if (error)
142 		return (error);
143 
144 	error = mac_check_structmac_consistent(&mac);
145 	if (error)
146 		return (error);
147 
148 	elements = malloc(mac.m_buflen, M_MACTEMP, M_WAITOK);
149 	error = copyinstr(mac.m_string, elements, mac.m_buflen, NULL);
150 	if (error) {
151 		free(elements, M_MACTEMP);
152 		return (error);
153 	}
154 
155 	buffer = malloc(mac.m_buflen, M_MACTEMP, M_WAITOK | M_ZERO);
156 	error = mac_cred_externalize_label(td->td_ucred->cr_label,
157 	    elements, buffer, mac.m_buflen);
158 	if (error == 0)
159 		error = copyout(buffer, mac.m_string, strlen(buffer)+1);
160 
161 	free(buffer, M_MACTEMP);
162 	free(elements, M_MACTEMP);
163 	return (error);
164 }
165 
166 int
167 sys___mac_set_proc(struct thread *td, struct __mac_set_proc_args *uap)
168 {
169 	struct ucred *newcred, *oldcred;
170 	struct label *intlabel;
171 	struct proc *p;
172 	struct mac mac;
173 	char *buffer;
174 	int error;
175 
176 	if (!(mac_labeled & MPC_OBJECT_CRED))
177 		return (EINVAL);
178 
179 	error = copyin(uap->mac_p, &mac, sizeof(mac));
180 	if (error)
181 		return (error);
182 
183 	error = mac_check_structmac_consistent(&mac);
184 	if (error)
185 		return (error);
186 
187 	buffer = malloc(mac.m_buflen, M_MACTEMP, M_WAITOK);
188 	error = copyinstr(mac.m_string, buffer, mac.m_buflen, NULL);
189 	if (error) {
190 		free(buffer, M_MACTEMP);
191 		return (error);
192 	}
193 
194 	intlabel = mac_cred_label_alloc();
195 	error = mac_cred_internalize_label(intlabel, buffer);
196 	free(buffer, M_MACTEMP);
197 	if (error)
198 		goto out;
199 
200 	newcred = crget();
201 
202 	p = td->td_proc;
203 	PROC_LOCK(p);
204 	oldcred = p->p_ucred;
205 
206 	error = mac_cred_check_relabel(oldcred, intlabel);
207 	if (error) {
208 		PROC_UNLOCK(p);
209 		crfree(newcred);
210 		goto out;
211 	}
212 
213 	setsugid(p);
214 	crcopy(newcred, oldcred);
215 	mac_cred_relabel(newcred, intlabel);
216 	proc_set_cred(p, newcred);
217 
218 	PROC_UNLOCK(p);
219 	crfree(oldcred);
220 	mac_proc_vm_revoke(td);
221 
222 out:
223 	mac_cred_label_free(intlabel);
224 	return (error);
225 }
226 
227 int
228 sys___mac_get_fd(struct thread *td, struct __mac_get_fd_args *uap)
229 {
230 	char *elements, *buffer;
231 	struct label *intlabel;
232 	struct file *fp;
233 	struct mac mac;
234 	struct vnode *vp;
235 	struct pipe *pipe;
236 	struct socket *so;
237 	cap_rights_t rights;
238 	int error;
239 
240 	error = copyin(uap->mac_p, &mac, sizeof(mac));
241 	if (error)
242 		return (error);
243 
244 	error = mac_check_structmac_consistent(&mac);
245 	if (error)
246 		return (error);
247 
248 	elements = malloc(mac.m_buflen, M_MACTEMP, M_WAITOK);
249 	error = copyinstr(mac.m_string, elements, mac.m_buflen, NULL);
250 	if (error) {
251 		free(elements, M_MACTEMP);
252 		return (error);
253 	}
254 
255 	buffer = malloc(mac.m_buflen, M_MACTEMP, M_WAITOK | M_ZERO);
256 	error = fget(td, uap->fd, cap_rights_init_one(&rights, CAP_MAC_GET),
257 	    &fp);
258 	if (error)
259 		goto out;
260 
261 	switch (fp->f_type) {
262 	case DTYPE_FIFO:
263 	case DTYPE_VNODE:
264 		if (!(mac_labeled & MPC_OBJECT_VNODE)) {
265 			error = EINVAL;
266 			goto out_fdrop;
267 		}
268 		vp = fp->f_vnode;
269 		intlabel = mac_vnode_label_alloc();
270 		vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
271 		mac_vnode_copy_label(vp->v_label, intlabel);
272 		VOP_UNLOCK(vp);
273 		error = mac_vnode_externalize_label(intlabel, elements,
274 		    buffer, mac.m_buflen);
275 		mac_vnode_label_free(intlabel);
276 		break;
277 
278 	case DTYPE_PIPE:
279 		if (!(mac_labeled & MPC_OBJECT_PIPE)) {
280 			error = EINVAL;
281 			goto out_fdrop;
282 		}
283 		pipe = fp->f_data;
284 		intlabel = mac_pipe_label_alloc();
285 		PIPE_LOCK(pipe);
286 		mac_pipe_copy_label(pipe->pipe_pair->pp_label, intlabel);
287 		PIPE_UNLOCK(pipe);
288 		error = mac_pipe_externalize_label(intlabel, elements,
289 		    buffer, mac.m_buflen);
290 		mac_pipe_label_free(intlabel);
291 		break;
292 
293 	case DTYPE_SOCKET:
294 		if (!(mac_labeled & MPC_OBJECT_SOCKET)) {
295 			error = EINVAL;
296 			goto out_fdrop;
297 		}
298 		so = fp->f_data;
299 		intlabel = mac_socket_label_alloc(M_WAITOK);
300 		SOCK_LOCK(so);
301 		mac_socket_copy_label(so->so_label, intlabel);
302 		SOCK_UNLOCK(so);
303 		error = mac_socket_externalize_label(intlabel, elements,
304 		    buffer, mac.m_buflen);
305 		mac_socket_label_free(intlabel);
306 		break;
307 
308 	default:
309 		error = EINVAL;
310 	}
311 	if (error == 0)
312 		error = copyout(buffer, mac.m_string, strlen(buffer)+1);
313 out_fdrop:
314 	fdrop(fp, td);
315 out:
316 	free(buffer, M_MACTEMP);
317 	free(elements, M_MACTEMP);
318 	return (error);
319 }
320 
321 int
322 sys___mac_get_file(struct thread *td, struct __mac_get_file_args *uap)
323 {
324 
325 	return (kern___mac_get_path(td, uap->path_p, uap->mac_p, FOLLOW));
326 }
327 
328 int
329 sys___mac_get_link(struct thread *td, struct __mac_get_link_args *uap)
330 {
331 
332 	return (kern___mac_get_path(td, uap->path_p, uap->mac_p, NOFOLLOW));
333 }
334 
335 static int
336 kern___mac_get_path(struct thread *td, const char *path_p, struct mac *mac_p,
337    int follow)
338 {
339 	char *elements, *buffer;
340 	struct nameidata nd;
341 	struct label *intlabel;
342 	struct mac mac;
343 	int error;
344 
345 	if (!(mac_labeled & MPC_OBJECT_VNODE))
346 		return (EINVAL);
347 
348 	error = copyin(mac_p, &mac, sizeof(mac));
349 	if (error)
350 		return (error);
351 
352 	error = mac_check_structmac_consistent(&mac);
353 	if (error)
354 		return (error);
355 
356 	elements = malloc(mac.m_buflen, M_MACTEMP, M_WAITOK);
357 	error = copyinstr(mac.m_string, elements, mac.m_buflen, NULL);
358 	if (error) {
359 		free(elements, M_MACTEMP);
360 		return (error);
361 	}
362 
363 	buffer = malloc(mac.m_buflen, M_MACTEMP, M_WAITOK | M_ZERO);
364 	NDINIT(&nd, LOOKUP, LOCKLEAF | follow, UIO_USERSPACE, path_p, td);
365 	error = namei(&nd);
366 	if (error)
367 		goto out;
368 
369 	intlabel = mac_vnode_label_alloc();
370 	mac_vnode_copy_label(nd.ni_vp->v_label, intlabel);
371 	error = mac_vnode_externalize_label(intlabel, elements, buffer,
372 	    mac.m_buflen);
373 	NDFREE(&nd, 0);
374 	mac_vnode_label_free(intlabel);
375 
376 	if (error == 0)
377 		error = copyout(buffer, mac.m_string, strlen(buffer)+1);
378 
379 out:
380 	free(buffer, M_MACTEMP);
381 	free(elements, M_MACTEMP);
382 
383 	return (error);
384 }
385 
386 int
387 sys___mac_set_fd(struct thread *td, struct __mac_set_fd_args *uap)
388 {
389 	struct label *intlabel;
390 	struct pipe *pipe;
391 	struct socket *so;
392 	struct file *fp;
393 	struct mount *mp;
394 	struct vnode *vp;
395 	struct mac mac;
396 	cap_rights_t rights;
397 	char *buffer;
398 	int error;
399 
400 	error = copyin(uap->mac_p, &mac, sizeof(mac));
401 	if (error)
402 		return (error);
403 
404 	error = mac_check_structmac_consistent(&mac);
405 	if (error)
406 		return (error);
407 
408 	buffer = malloc(mac.m_buflen, M_MACTEMP, M_WAITOK);
409 	error = copyinstr(mac.m_string, buffer, mac.m_buflen, NULL);
410 	if (error) {
411 		free(buffer, M_MACTEMP);
412 		return (error);
413 	}
414 
415 	error = fget(td, uap->fd, cap_rights_init_one(&rights, CAP_MAC_SET),
416 	    &fp);
417 	if (error)
418 		goto out;
419 
420 	switch (fp->f_type) {
421 	case DTYPE_FIFO:
422 	case DTYPE_VNODE:
423 		if (!(mac_labeled & MPC_OBJECT_VNODE)) {
424 			error = EINVAL;
425 			goto out_fdrop;
426 		}
427 		intlabel = mac_vnode_label_alloc();
428 		error = mac_vnode_internalize_label(intlabel, buffer);
429 		if (error) {
430 			mac_vnode_label_free(intlabel);
431 			break;
432 		}
433 		vp = fp->f_vnode;
434 		error = vn_start_write(vp, &mp, V_WAIT | PCATCH);
435 		if (error != 0) {
436 			mac_vnode_label_free(intlabel);
437 			break;
438 		}
439 		vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
440 		error = vn_setlabel(vp, intlabel, td->td_ucred);
441 		VOP_UNLOCK(vp);
442 		vn_finished_write(mp);
443 		mac_vnode_label_free(intlabel);
444 		break;
445 
446 	case DTYPE_PIPE:
447 		if (!(mac_labeled & MPC_OBJECT_PIPE)) {
448 			error = EINVAL;
449 			goto out_fdrop;
450 		}
451 		intlabel = mac_pipe_label_alloc();
452 		error = mac_pipe_internalize_label(intlabel, buffer);
453 		if (error == 0) {
454 			pipe = fp->f_data;
455 			PIPE_LOCK(pipe);
456 			error = mac_pipe_label_set(td->td_ucred,
457 			    pipe->pipe_pair, intlabel);
458 			PIPE_UNLOCK(pipe);
459 		}
460 		mac_pipe_label_free(intlabel);
461 		break;
462 
463 	case DTYPE_SOCKET:
464 		if (!(mac_labeled & MPC_OBJECT_SOCKET)) {
465 			error = EINVAL;
466 			goto out_fdrop;
467 		}
468 		intlabel = mac_socket_label_alloc(M_WAITOK);
469 		error = mac_socket_internalize_label(intlabel, buffer);
470 		if (error == 0) {
471 			so = fp->f_data;
472 			error = mac_socket_label_set(td->td_ucred, so,
473 			    intlabel);
474 		}
475 		mac_socket_label_free(intlabel);
476 		break;
477 
478 	default:
479 		error = EINVAL;
480 	}
481 out_fdrop:
482 	fdrop(fp, td);
483 out:
484 	free(buffer, M_MACTEMP);
485 	return (error);
486 }
487 
488 int
489 sys___mac_set_file(struct thread *td, struct __mac_set_file_args *uap)
490 {
491 
492 	return (kern___mac_set_path(td, uap->path_p, uap->mac_p, FOLLOW));
493 }
494 
495 int
496 sys___mac_set_link(struct thread *td, struct __mac_set_link_args *uap)
497 {
498 
499 	return (kern___mac_set_path(td, uap->path_p, uap->mac_p, NOFOLLOW));
500 }
501 
502 static int
503 kern___mac_set_path(struct thread *td, const char *path_p, struct mac *mac_p,
504     int follow)
505 {
506 	struct label *intlabel;
507 	struct nameidata nd;
508 	struct mount *mp;
509 	struct mac mac;
510 	char *buffer;
511 	int error;
512 
513 	if (!(mac_labeled & MPC_OBJECT_VNODE))
514 		return (EINVAL);
515 
516 	error = copyin(mac_p, &mac, sizeof(mac));
517 	if (error)
518 		return (error);
519 
520 	error = mac_check_structmac_consistent(&mac);
521 	if (error)
522 		return (error);
523 
524 	buffer = malloc(mac.m_buflen, M_MACTEMP, M_WAITOK);
525 	error = copyinstr(mac.m_string, buffer, mac.m_buflen, NULL);
526 	if (error) {
527 		free(buffer, M_MACTEMP);
528 		return (error);
529 	}
530 
531 	intlabel = mac_vnode_label_alloc();
532 	error = mac_vnode_internalize_label(intlabel, buffer);
533 	free(buffer, M_MACTEMP);
534 	if (error)
535 		goto out;
536 
537 	NDINIT(&nd, LOOKUP, LOCKLEAF | follow, UIO_USERSPACE, path_p, td);
538 	error = namei(&nd);
539 	if (error == 0) {
540 		error = vn_start_write(nd.ni_vp, &mp, V_WAIT | PCATCH);
541 		if (error == 0) {
542 			error = vn_setlabel(nd.ni_vp, intlabel,
543 			    td->td_ucred);
544 			vn_finished_write(mp);
545 		}
546 	}
547 
548 	NDFREE(&nd, 0);
549 out:
550 	mac_vnode_label_free(intlabel);
551 	return (error);
552 }
553 
554 int
555 sys_mac_syscall(struct thread *td, struct mac_syscall_args *uap)
556 {
557 	struct mac_policy_conf *mpc;
558 	char target[MAC_MAX_POLICY_NAME];
559 	int error;
560 
561 	error = copyinstr(uap->policy, target, sizeof(target), NULL);
562 	if (error)
563 		return (error);
564 
565 	error = ENOSYS;
566 	LIST_FOREACH(mpc, &mac_static_policy_list, mpc_list) {
567 		if (strcmp(mpc->mpc_name, target) == 0 &&
568 		    mpc->mpc_ops->mpo_syscall != NULL) {
569 			error = mpc->mpc_ops->mpo_syscall(td,
570 			    uap->call, uap->arg);
571 			goto out;
572 		}
573 	}
574 
575 	if (!LIST_EMPTY(&mac_policy_list)) {
576 		mac_policy_slock_sleep();
577 		LIST_FOREACH(mpc, &mac_policy_list, mpc_list) {
578 			if (strcmp(mpc->mpc_name, target) == 0 &&
579 			    mpc->mpc_ops->mpo_syscall != NULL) {
580 				error = mpc->mpc_ops->mpo_syscall(td,
581 				    uap->call, uap->arg);
582 				break;
583 			}
584 		}
585 		mac_policy_sunlock_sleep();
586 	}
587 out:
588 	return (error);
589 }
590 
591 #else /* !MAC */
592 
593 int
594 sys___mac_get_pid(struct thread *td, struct __mac_get_pid_args *uap)
595 {
596 
597 	return (ENOSYS);
598 }
599 
600 int
601 sys___mac_get_proc(struct thread *td, struct __mac_get_proc_args *uap)
602 {
603 
604 	return (ENOSYS);
605 }
606 
607 int
608 sys___mac_set_proc(struct thread *td, struct __mac_set_proc_args *uap)
609 {
610 
611 	return (ENOSYS);
612 }
613 
614 int
615 sys___mac_get_fd(struct thread *td, struct __mac_get_fd_args *uap)
616 {
617 
618 	return (ENOSYS);
619 }
620 
621 int
622 sys___mac_get_file(struct thread *td, struct __mac_get_file_args *uap)
623 {
624 
625 	return (ENOSYS);
626 }
627 
628 int
629 sys___mac_get_link(struct thread *td, struct __mac_get_link_args *uap)
630 {
631 
632 	return (ENOSYS);
633 }
634 
635 int
636 sys___mac_set_fd(struct thread *td, struct __mac_set_fd_args *uap)
637 {
638 
639 	return (ENOSYS);
640 }
641 
642 int
643 sys___mac_set_file(struct thread *td, struct __mac_set_file_args *uap)
644 {
645 
646 	return (ENOSYS);
647 }
648 
649 int
650 sys___mac_set_link(struct thread *td, struct __mac_set_link_args *uap)
651 {
652 
653 	return (ENOSYS);
654 }
655 
656 int
657 sys_mac_syscall(struct thread *td, struct mac_syscall_args *uap)
658 {
659 
660 	return (ENOSYS);
661 }
662 
663 #endif /* !MAC */
664