FreeBSD/Linux Kernel Cross Reference
sys/kern/kern_jail.c
1 /*-
2 * ----------------------------------------------------------------------------
3 * "THE BEER-WARE LICENSE" (Revision 42):
4 * <phk@FreeBSD.ORG> wrote this file. As long as you retain this notice you
5 * can do whatever you want with this stuff. If we meet some day, and you think
6 * this stuff is worth it, you can buy me a beer in return. Poul-Henning Kamp
7 * ----------------------------------------------------------------------------
8 */
9
10 #include <sys/cdefs.h>
11 __FBSDID("$FreeBSD$");
12
13 #include "opt_mac.h"
14
15 #include <sys/param.h>
16 #include <sys/types.h>
17 #include <sys/kernel.h>
18 #include <sys/systm.h>
19 #include <sys/errno.h>
20 #include <sys/sysproto.h>
21 #include <sys/malloc.h>
22 #include <sys/priv.h>
23 #include <sys/proc.h>
24 #include <sys/taskqueue.h>
25 #include <sys/jail.h>
26 #include <sys/lock.h>
27 #include <sys/mutex.h>
28 #include <sys/sx.h>
29 #include <sys/namei.h>
30 #include <sys/mount.h>
31 #include <sys/queue.h>
32 #include <sys/socket.h>
33 #include <sys/syscallsubr.h>
34 #include <sys/sysctl.h>
35 #include <sys/vnode.h>
36 #include <net/if.h>
37 #include <netinet/in.h>
38
39 #include <security/mac/mac_framework.h>
40
41 MALLOC_DEFINE(M_PRISON, "prison", "Prison structures");
42
43 SYSCTL_NODE(_security, OID_AUTO, jail, CTLFLAG_RW, 0,
44 "Jail rules");
45
46 int jail_set_hostname_allowed = 1;
47 SYSCTL_INT(_security_jail, OID_AUTO, set_hostname_allowed, CTLFLAG_RW,
48 &jail_set_hostname_allowed, 0,
49 "Processes in jail can set their hostnames");
50
51 int jail_socket_unixiproute_only = 1;
52 SYSCTL_INT(_security_jail, OID_AUTO, socket_unixiproute_only, CTLFLAG_RW,
53 &jail_socket_unixiproute_only, 0,
54 "Processes in jail are limited to creating UNIX/IPv4/route sockets only");
55
56 int jail_sysvipc_allowed = 0;
57 SYSCTL_INT(_security_jail, OID_AUTO, sysvipc_allowed, CTLFLAG_RW,
58 &jail_sysvipc_allowed, 0,
59 "Processes in jail can use System V IPC primitives");
60
61 static int jail_enforce_statfs = 2;
62 SYSCTL_INT(_security_jail, OID_AUTO, enforce_statfs, CTLFLAG_RW,
63 &jail_enforce_statfs, 0,
64 "Processes in jail cannot see all mounted file systems");
65
66 int jail_allow_raw_sockets = 0;
67 SYSCTL_INT(_security_jail, OID_AUTO, allow_raw_sockets, CTLFLAG_RW,
68 &jail_allow_raw_sockets, 0,
69 "Prison root can create raw sockets");
70
71 int jail_chflags_allowed = 0;
72 SYSCTL_INT(_security_jail, OID_AUTO, chflags_allowed, CTLFLAG_RW,
73 &jail_chflags_allowed, 0,
74 "Processes in jail can alter system file flags");
75
76 int jail_mount_allowed = 0;
77 SYSCTL_INT(_security_jail, OID_AUTO, mount_allowed, CTLFLAG_RW,
78 &jail_mount_allowed, 0,
79 "Processes in jail can mount/unmount jail-friendly file systems");
80
81 /* allprison, lastprid, and prisoncount are protected by allprison_lock. */
82 struct prisonlist allprison;
83 struct sx allprison_lock;
84 int lastprid = 0;
85 int prisoncount = 0;
86
87 /*
88 * List of jail services. Protected by allprison_lock.
89 */
90 TAILQ_HEAD(prison_services_head, prison_service);
91 static struct prison_services_head prison_services =
92 TAILQ_HEAD_INITIALIZER(prison_services);
93 static int prison_service_slots = 0;
94
95 struct prison_service {
96 prison_create_t ps_create;
97 prison_destroy_t ps_destroy;
98 int ps_slotno;
99 TAILQ_ENTRY(prison_service) ps_next;
100 char ps_name[0];
101 };
102
103 static void init_prison(void *);
104 static void prison_complete(void *context, int pending);
105 static int sysctl_jail_list(SYSCTL_HANDLER_ARGS);
106
107 static void
108 init_prison(void *data __unused)
109 {
110
111 sx_init(&allprison_lock, "allprison");
112 LIST_INIT(&allprison);
113 }
114
115 SYSINIT(prison, SI_SUB_INTRINSIC, SI_ORDER_ANY, init_prison, NULL);
116
117 /*
118 * struct jail_args {
119 * struct jail *jail;
120 * };
121 */
122 int
123 jail(struct thread *td, struct jail_args *uap)
124 {
125 struct nameidata nd;
126 struct prison *pr, *tpr;
127 struct prison_service *psrv;
128 struct jail j;
129 struct jail_attach_args jaa;
130 int vfslocked, error, tryprid;
131
132 error = copyin(uap->jail, &j, sizeof(j));
133 if (error)
134 return (error);
135 if (j.version != 0)
136 return (EINVAL);
137
138 MALLOC(pr, struct prison *, sizeof(*pr), M_PRISON, M_WAITOK | M_ZERO);
139 mtx_init(&pr->pr_mtx, "jail mutex", NULL, MTX_DEF);
140 pr->pr_ref = 1;
141 error = copyinstr(j.path, &pr->pr_path, sizeof(pr->pr_path), 0);
142 if (error)
143 goto e_killmtx;
144 NDINIT(&nd, LOOKUP, MPSAFE | FOLLOW | LOCKLEAF, UIO_SYSSPACE,
145 pr->pr_path, td);
146 error = namei(&nd);
147 if (error)
148 goto e_killmtx;
149 vfslocked = NDHASGIANT(&nd);
150 pr->pr_root = nd.ni_vp;
151 VOP_UNLOCK(nd.ni_vp, 0, td);
152 NDFREE(&nd, NDF_ONLY_PNBUF);
153 VFS_UNLOCK_GIANT(vfslocked);
154 error = copyinstr(j.hostname, &pr->pr_host, sizeof(pr->pr_host), 0);
155 if (error)
156 goto e_dropvnref;
157 pr->pr_ip = j.ip_number;
158 pr->pr_linux = NULL;
159 pr->pr_securelevel = securelevel;
160 if (prison_service_slots == 0)
161 pr->pr_slots = NULL;
162 else {
163 pr->pr_slots = malloc(sizeof(*pr->pr_slots) * prison_service_slots,
164 M_PRISON, M_ZERO | M_WAITOK);
165 }
166
167 /* Determine next pr_id and add prison to allprison list. */
168 sx_xlock(&allprison_lock);
169 tryprid = lastprid + 1;
170 if (tryprid == JAIL_MAX)
171 tryprid = 1;
172 next:
173 LIST_FOREACH(tpr, &allprison, pr_list) {
174 if (tpr->pr_id == tryprid) {
175 tryprid++;
176 if (tryprid == JAIL_MAX) {
177 sx_xunlock(&allprison_lock);
178 error = EAGAIN;
179 goto e_dropvnref;
180 }
181 goto next;
182 }
183 }
184 pr->pr_id = jaa.jid = lastprid = tryprid;
185 LIST_INSERT_HEAD(&allprison, pr, pr_list);
186 prisoncount++;
187 sx_downgrade(&allprison_lock);
188 TAILQ_FOREACH(psrv, &prison_services, ps_next) {
189 psrv->ps_create(psrv, pr);
190 }
191 sx_sunlock(&allprison_lock);
192
193 error = jail_attach(td, &jaa);
194 if (error)
195 goto e_dropprref;
196 mtx_lock(&pr->pr_mtx);
197 pr->pr_ref--;
198 mtx_unlock(&pr->pr_mtx);
199 td->td_retval[0] = jaa.jid;
200 return (0);
201 e_dropprref:
202 sx_xlock(&allprison_lock);
203 LIST_REMOVE(pr, pr_list);
204 prisoncount--;
205 sx_downgrade(&allprison_lock);
206 TAILQ_FOREACH(psrv, &prison_services, ps_next) {
207 psrv->ps_destroy(psrv, pr);
208 }
209 sx_sunlock(&allprison_lock);
210 e_dropvnref:
211 vfslocked = VFS_LOCK_GIANT(pr->pr_root->v_mount);
212 vrele(pr->pr_root);
213 VFS_UNLOCK_GIANT(vfslocked);
214 e_killmtx:
215 mtx_destroy(&pr->pr_mtx);
216 FREE(pr, M_PRISON);
217 return (error);
218 }
219
220 /*
221 * struct jail_attach_args {
222 * int jid;
223 * };
224 */
225 int
226 jail_attach(struct thread *td, struct jail_attach_args *uap)
227 {
228 struct proc *p;
229 struct ucred *newcred, *oldcred;
230 struct prison *pr;
231 int vfslocked, error;
232
233 /*
234 * XXX: Note that there is a slight race here if two threads
235 * in the same privileged process attempt to attach to two
236 * different jails at the same time. It is important for
237 * user processes not to do this, or they might end up with
238 * a process root from one prison, but attached to the jail
239 * of another.
240 */
241 error = priv_check(td, PRIV_JAIL_ATTACH);
242 if (error)
243 return (error);
244
245 p = td->td_proc;
246 sx_slock(&allprison_lock);
247 pr = prison_find(uap->jid);
248 if (pr == NULL) {
249 sx_sunlock(&allprison_lock);
250 return (EINVAL);
251 }
252 pr->pr_ref++;
253 mtx_unlock(&pr->pr_mtx);
254 sx_sunlock(&allprison_lock);
255
256 vfslocked = VFS_LOCK_GIANT(pr->pr_root->v_mount);
257 vn_lock(pr->pr_root, LK_EXCLUSIVE | LK_RETRY, td);
258 if ((error = change_dir(pr->pr_root, td)) != 0)
259 goto e_unlock;
260 #ifdef MAC
261 if ((error = mac_check_vnode_chroot(td->td_ucred, pr->pr_root)))
262 goto e_unlock;
263 #endif
264 VOP_UNLOCK(pr->pr_root, 0, td);
265 change_root(pr->pr_root, td);
266 VFS_UNLOCK_GIANT(vfslocked);
267
268 newcred = crget();
269 PROC_LOCK(p);
270 oldcred = p->p_ucred;
271 setsugid(p);
272 crcopy(newcred, oldcred);
273 newcred->cr_prison = pr;
274 p->p_ucred = newcred;
275 PROC_UNLOCK(p);
276 crfree(oldcred);
277 return (0);
278 e_unlock:
279 VOP_UNLOCK(pr->pr_root, 0, td);
280 VFS_UNLOCK_GIANT(vfslocked);
281 mtx_lock(&pr->pr_mtx);
282 pr->pr_ref--;
283 mtx_unlock(&pr->pr_mtx);
284 return (error);
285 }
286
287 /*
288 * Returns a locked prison instance, or NULL on failure.
289 */
290 struct prison *
291 prison_find(int prid)
292 {
293 struct prison *pr;
294
295 sx_assert(&allprison_lock, SX_LOCKED);
296 LIST_FOREACH(pr, &allprison, pr_list) {
297 if (pr->pr_id == prid) {
298 mtx_lock(&pr->pr_mtx);
299 if (pr->pr_ref == 0) {
300 mtx_unlock(&pr->pr_mtx);
301 break;
302 }
303 return (pr);
304 }
305 }
306 return (NULL);
307 }
308
309 void
310 prison_free(struct prison *pr)
311 {
312
313 mtx_lock(&pr->pr_mtx);
314 pr->pr_ref--;
315 if (pr->pr_ref == 0) {
316 mtx_unlock(&pr->pr_mtx);
317 TASK_INIT(&pr->pr_task, 0, prison_complete, pr);
318 taskqueue_enqueue(taskqueue_thread, &pr->pr_task);
319 return;
320 }
321 mtx_unlock(&pr->pr_mtx);
322 }
323
324 static void
325 prison_complete(void *context, int pending)
326 {
327 struct prison_service *psrv;
328 struct prison *pr;
329 int vfslocked;
330
331 pr = (struct prison *)context;
332
333 sx_xlock(&allprison_lock);
334 LIST_REMOVE(pr, pr_list);
335 prisoncount--;
336 sx_downgrade(&allprison_lock);
337 TAILQ_FOREACH(psrv, &prison_services, ps_next) {
338 psrv->ps_destroy(psrv, pr);
339 }
340 sx_sunlock(&allprison_lock);
341
342 vfslocked = VFS_LOCK_GIANT(pr->pr_root->v_mount);
343 vrele(pr->pr_root);
344 VFS_UNLOCK_GIANT(vfslocked);
345
346 mtx_destroy(&pr->pr_mtx);
347 if (pr->pr_linux != NULL)
348 FREE(pr->pr_linux, M_PRISON);
349 FREE(pr, M_PRISON);
350 }
351
352 void
353 prison_hold(struct prison *pr)
354 {
355
356 mtx_lock(&pr->pr_mtx);
357 KASSERT(pr->pr_ref > 0,
358 ("Trying to hold dead prison (id=%d).", pr->pr_id));
359 pr->pr_ref++;
360 mtx_unlock(&pr->pr_mtx);
361 }
362
363 u_int32_t
364 prison_getip(struct ucred *cred)
365 {
366
367 return (cred->cr_prison->pr_ip);
368 }
369
370 int
371 prison_ip(struct ucred *cred, int flag, u_int32_t *ip)
372 {
373 u_int32_t tmp;
374
375 if (!jailed(cred))
376 return (0);
377 if (flag)
378 tmp = *ip;
379 else
380 tmp = ntohl(*ip);
381 if (tmp == INADDR_ANY) {
382 if (flag)
383 *ip = cred->cr_prison->pr_ip;
384 else
385 *ip = htonl(cred->cr_prison->pr_ip);
386 return (0);
387 }
388 if (tmp == INADDR_LOOPBACK) {
389 if (flag)
390 *ip = cred->cr_prison->pr_ip;
391 else
392 *ip = htonl(cred->cr_prison->pr_ip);
393 return (0);
394 }
395 if (cred->cr_prison->pr_ip != tmp)
396 return (1);
397 return (0);
398 }
399
400 void
401 prison_remote_ip(struct ucred *cred, int flag, u_int32_t *ip)
402 {
403 u_int32_t tmp;
404
405 if (!jailed(cred))
406 return;
407 if (flag)
408 tmp = *ip;
409 else
410 tmp = ntohl(*ip);
411 if (tmp == INADDR_LOOPBACK) {
412 if (flag)
413 *ip = cred->cr_prison->pr_ip;
414 else
415 *ip = htonl(cred->cr_prison->pr_ip);
416 return;
417 }
418 return;
419 }
420
421 int
422 prison_if(struct ucred *cred, struct sockaddr *sa)
423 {
424 struct sockaddr_in *sai;
425 int ok;
426
427 sai = (struct sockaddr_in *)sa;
428 if ((sai->sin_family != AF_INET) && jail_socket_unixiproute_only)
429 ok = 1;
430 else if (sai->sin_family != AF_INET)
431 ok = 0;
432 else if (cred->cr_prison->pr_ip != ntohl(sai->sin_addr.s_addr))
433 ok = 1;
434 else
435 ok = 0;
436 return (ok);
437 }
438
439 /*
440 * Return 0 if jails permit p1 to frob p2, otherwise ESRCH.
441 */
442 int
443 prison_check(struct ucred *cred1, struct ucred *cred2)
444 {
445
446 if (jailed(cred1)) {
447 if (!jailed(cred2))
448 return (ESRCH);
449 if (cred2->cr_prison != cred1->cr_prison)
450 return (ESRCH);
451 }
452
453 return (0);
454 }
455
456 /*
457 * Return 1 if the passed credential is in a jail, otherwise 0.
458 */
459 int
460 jailed(struct ucred *cred)
461 {
462
463 return (cred->cr_prison != NULL);
464 }
465
466 /*
467 * Return the correct hostname for the passed credential.
468 */
469 void
470 getcredhostname(struct ucred *cred, char *buf, size_t size)
471 {
472
473 if (jailed(cred)) {
474 mtx_lock(&cred->cr_prison->pr_mtx);
475 strlcpy(buf, cred->cr_prison->pr_host, size);
476 mtx_unlock(&cred->cr_prison->pr_mtx);
477 } else
478 strlcpy(buf, hostname, size);
479 }
480
481 /*
482 * Determine whether the subject represented by cred can "see"
483 * status of a mount point.
484 * Returns: 0 for permitted, ENOENT otherwise.
485 * XXX: This function should be called cr_canseemount() and should be
486 * placed in kern_prot.c.
487 */
488 int
489 prison_canseemount(struct ucred *cred, struct mount *mp)
490 {
491 struct prison *pr;
492 struct statfs *sp;
493 size_t len;
494
495 if (!jailed(cred) || jail_enforce_statfs == 0)
496 return (0);
497 pr = cred->cr_prison;
498 if (pr->pr_root->v_mount == mp)
499 return (0);
500 if (jail_enforce_statfs == 2)
501 return (ENOENT);
502 /*
503 * If jail's chroot directory is set to "/" we should be able to see
504 * all mount-points from inside a jail.
505 * This is ugly check, but this is the only situation when jail's
506 * directory ends with '/'.
507 */
508 if (strcmp(pr->pr_path, "/") == 0)
509 return (0);
510 len = strlen(pr->pr_path);
511 sp = &mp->mnt_stat;
512 if (strncmp(pr->pr_path, sp->f_mntonname, len) != 0)
513 return (ENOENT);
514 /*
515 * Be sure that we don't have situation where jail's root directory
516 * is "/some/path" and mount point is "/some/pathpath".
517 */
518 if (sp->f_mntonname[len] != '\0' && sp->f_mntonname[len] != '/')
519 return (ENOENT);
520 return (0);
521 }
522
523 void
524 prison_enforce_statfs(struct ucred *cred, struct mount *mp, struct statfs *sp)
525 {
526 char jpath[MAXPATHLEN];
527 struct prison *pr;
528 size_t len;
529
530 if (!jailed(cred) || jail_enforce_statfs == 0)
531 return;
532 pr = cred->cr_prison;
533 if (prison_canseemount(cred, mp) != 0) {
534 bzero(sp->f_mntonname, sizeof(sp->f_mntonname));
535 strlcpy(sp->f_mntonname, "[restricted]",
536 sizeof(sp->f_mntonname));
537 return;
538 }
539 if (pr->pr_root->v_mount == mp) {
540 /*
541 * Clear current buffer data, so we are sure nothing from
542 * the valid path left there.
543 */
544 bzero(sp->f_mntonname, sizeof(sp->f_mntonname));
545 *sp->f_mntonname = '/';
546 return;
547 }
548 /*
549 * If jail's chroot directory is set to "/" we should be able to see
550 * all mount-points from inside a jail.
551 */
552 if (strcmp(pr->pr_path, "/") == 0)
553 return;
554 len = strlen(pr->pr_path);
555 strlcpy(jpath, sp->f_mntonname + len, sizeof(jpath));
556 /*
557 * Clear current buffer data, so we are sure nothing from
558 * the valid path left there.
559 */
560 bzero(sp->f_mntonname, sizeof(sp->f_mntonname));
561 if (*jpath == '\0') {
562 /* Should never happen. */
563 *sp->f_mntonname = '/';
564 } else {
565 strlcpy(sp->f_mntonname, jpath, sizeof(sp->f_mntonname));
566 }
567 }
568
569 /*
570 * Check with permission for a specific privilege is granted within jail. We
571 * have a specific list of accepted privileges; the rest are denied.
572 */
573 int
574 prison_priv_check(struct ucred *cred, int priv)
575 {
576
577 if (!jailed(cred))
578 return (0);
579
580 switch (priv) {
581
582 /*
583 * Allow ktrace privileges for root in jail.
584 */
585 case PRIV_KTRACE:
586
587 #if 0
588 /*
589 * Allow jailed processes to configure audit identity and
590 * submit audit records (login, etc). In the future we may
591 * want to further refine the relationship between audit and
592 * jail.
593 */
594 case PRIV_AUDIT_GETAUDIT:
595 case PRIV_AUDIT_SETAUDIT:
596 case PRIV_AUDIT_SUBMIT:
597 #endif
598
599 /*
600 * Allow jailed processes to manipulate process UNIX
601 * credentials in any way they see fit.
602 */
603 case PRIV_CRED_SETUID:
604 case PRIV_CRED_SETEUID:
605 case PRIV_CRED_SETGID:
606 case PRIV_CRED_SETEGID:
607 case PRIV_CRED_SETGROUPS:
608 case PRIV_CRED_SETREUID:
609 case PRIV_CRED_SETREGID:
610 case PRIV_CRED_SETRESUID:
611 case PRIV_CRED_SETRESGID:
612
613 /*
614 * Jail implements visibility constraints already, so allow
615 * jailed root to override uid/gid-based constraints.
616 */
617 case PRIV_SEEOTHERGIDS:
618 case PRIV_SEEOTHERUIDS:
619
620 /*
621 * Jail implements inter-process debugging limits already, so
622 * allow jailed root various debugging privileges.
623 */
624 case PRIV_DEBUG_DIFFCRED:
625 case PRIV_DEBUG_SUGID:
626 case PRIV_DEBUG_UNPRIV:
627
628 /*
629 * Allow jail to set various resource limits and login
630 * properties, and for now, exceed process resource limits.
631 */
632 case PRIV_PROC_LIMIT:
633 case PRIV_PROC_SETLOGIN:
634 case PRIV_PROC_SETRLIMIT:
635
636 /*
637 * System V and POSIX IPC privileges are granted in jail.
638 */
639 case PRIV_IPC_READ:
640 case PRIV_IPC_WRITE:
641 case PRIV_IPC_ADMIN:
642 case PRIV_IPC_MSGSIZE:
643 case PRIV_MQ_ADMIN:
644
645 /*
646 * Jail implements its own inter-process limits, so allow
647 * root processes in jail to change scheduling on other
648 * processes in the same jail. Likewise for signalling.
649 */
650 case PRIV_SCHED_DIFFCRED:
651 case PRIV_SIGNAL_DIFFCRED:
652 case PRIV_SIGNAL_SUGID:
653
654 /*
655 * Allow jailed processes to write to sysctls marked as jail
656 * writable.
657 */
658 case PRIV_SYSCTL_WRITEJAIL:
659
660 /*
661 * Allow root in jail to manage a variety of quota
662 * properties. These should likely be conditional on a
663 * configuration option.
664 */
665 case PRIV_VFS_GETQUOTA:
666 case PRIV_VFS_SETQUOTA:
667
668 /*
669 * Since Jail relies on chroot() to implement file system
670 * protections, grant many VFS privileges to root in jail.
671 * Be careful to exclude mount-related and NFS-related
672 * privileges.
673 */
674 case PRIV_VFS_READ:
675 case PRIV_VFS_WRITE:
676 case PRIV_VFS_ADMIN:
677 case PRIV_VFS_EXEC:
678 case PRIV_VFS_LOOKUP:
679 case PRIV_VFS_BLOCKRESERVE: /* XXXRW: Slightly surprising. */
680 case PRIV_VFS_CHFLAGS_DEV:
681 case PRIV_VFS_CHOWN:
682 case PRIV_VFS_CHROOT:
683 case PRIV_VFS_RETAINSUGID:
684 case PRIV_VFS_FCHROOT:
685 case PRIV_VFS_LINK:
686 case PRIV_VFS_SETGID:
687 case PRIV_VFS_STICKYFILE:
688 return (0);
689
690 /*
691 * Depending on the global setting, allow privilege of
692 * setting system flags.
693 */
694 case PRIV_VFS_SYSFLAGS:
695 if (jail_chflags_allowed)
696 return (0);
697 else
698 return (EPERM);
699
700 /*
701 * Depending on the global setting, allow privilege of
702 * mounting/unmounting file systems.
703 */
704 case PRIV_VFS_MOUNT:
705 case PRIV_VFS_UNMOUNT:
706 case PRIV_VFS_MOUNT_NONUSER:
707 case PRIV_VFS_MOUNT_OWNER:
708 if (jail_mount_allowed)
709 return (0);
710 else
711 return (EPERM);
712
713 /*
714 * Allow jailed root to bind reserved ports and reuse in-use
715 * ports.
716 */
717 case PRIV_NETINET_RESERVEDPORT:
718 case PRIV_NETINET_REUSEPORT:
719 return (0);
720
721 /*
722 * Conditionally allow creating raw sockets in jail.
723 */
724 case PRIV_NETINET_RAW:
725 if (jail_allow_raw_sockets)
726 return (0);
727 else
728 return (EPERM);
729
730 /*
731 * Since jail implements its own visibility limits on netstat
732 * sysctls, allow getcred. This allows identd to work in
733 * jail.
734 */
735 case PRIV_NETINET_GETCRED:
736 return (0);
737
738 default:
739 /*
740 * In all remaining cases, deny the privilege request. This
741 * includes almost all network privileges, many system
742 * configuration privileges.
743 */
744 return (EPERM);
745 }
746 }
747
748 /*
749 * Register jail service. Provides 'create' and 'destroy' methods.
750 * 'create' method will be called for every existing jail and all
751 * jails in the future as they beeing created.
752 * 'destroy' method will be called for every jail going away and
753 * for all existing jails at the time of service deregistration.
754 */
755 struct prison_service *
756 prison_service_register(const char *name, prison_create_t create,
757 prison_destroy_t destroy)
758 {
759 struct prison_service *psrv, *psrv2;
760 struct prison *pr;
761 int reallocate = 1, slotno = 0;
762 void **slots, **oldslots;
763
764 psrv = malloc(sizeof(*psrv) + strlen(name) + 1, M_PRISON,
765 M_WAITOK | M_ZERO);
766 psrv->ps_create = create;
767 psrv->ps_destroy = destroy;
768 strcpy(psrv->ps_name, name);
769 /*
770 * Grab the allprison_lock here, so we won't miss any jail
771 * creation/destruction.
772 */
773 sx_xlock(&allprison_lock);
774 #ifdef INVARIANTS
775 /*
776 * Verify if service is not already registered.
777 */
778 TAILQ_FOREACH(psrv2, &prison_services, ps_next) {
779 KASSERT(strcmp(psrv2->ps_name, name) != 0,
780 ("jail service %s already registered", name));
781 }
782 #endif
783 /*
784 * Find free slot. When there is no existing free slot available,
785 * allocate one at the end.
786 */
787 TAILQ_FOREACH(psrv2, &prison_services, ps_next) {
788 if (psrv2->ps_slotno != slotno) {
789 KASSERT(slotno < psrv2->ps_slotno,
790 ("Invalid slotno (slotno=%d >= ps_slotno=%d",
791 slotno, psrv2->ps_slotno));
792 /* We found free slot. */
793 reallocate = 0;
794 break;
795 }
796 slotno++;
797 }
798 psrv->ps_slotno = slotno;
799 /*
800 * Keep the list sorted by slot number.
801 */
802 if (psrv2 != NULL) {
803 KASSERT(reallocate == 0, ("psrv2 != NULL && reallocate != 0"));
804 TAILQ_INSERT_BEFORE(psrv2, psrv, ps_next);
805 } else {
806 KASSERT(reallocate == 1, ("psrv2 == NULL && reallocate == 0"));
807 TAILQ_INSERT_TAIL(&prison_services, psrv, ps_next);
808 }
809 prison_service_slots++;
810 sx_downgrade(&allprison_lock);
811 /*
812 * Allocate memory for new slot if we didn't found empty one.
813 * Do not use realloc(9), because pr_slots is protected with a mutex,
814 * so we can't sleep.
815 */
816 LIST_FOREACH(pr, &allprison, pr_list) {
817 if (reallocate) {
818 /* First allocate memory with M_WAITOK. */
819 slots = malloc(sizeof(*slots) * prison_service_slots,
820 M_PRISON, M_WAITOK);
821 /* Now grab the mutex and replace pr_slots. */
822 mtx_lock(&pr->pr_mtx);
823 oldslots = pr->pr_slots;
824 if (psrv->ps_slotno > 0) {
825 bcopy(oldslots, slots,
826 sizeof(*slots) * (prison_service_slots - 1));
827 }
828 slots[psrv->ps_slotno] = NULL;
829 pr->pr_slots = slots;
830 mtx_unlock(&pr->pr_mtx);
831 if (oldslots != NULL)
832 free(oldslots, M_PRISON);
833 }
834 /*
835 * Call 'create' method for each existing jail.
836 */
837 psrv->ps_create(psrv, pr);
838 }
839 sx_sunlock(&allprison_lock);
840
841 return (psrv);
842 }
843
844 void
845 prison_service_deregister(struct prison_service *psrv)
846 {
847 struct prison *pr;
848 void **slots, **oldslots;
849 int last = 0;
850
851 sx_xlock(&allprison_lock);
852 if (TAILQ_LAST(&prison_services, prison_services_head) == psrv)
853 last = 1;
854 TAILQ_REMOVE(&prison_services, psrv, ps_next);
855 prison_service_slots--;
856 sx_downgrade(&allprison_lock);
857 LIST_FOREACH(pr, &allprison, pr_list) {
858 /*
859 * Call 'destroy' method for every currently existing jail.
860 */
861 psrv->ps_destroy(psrv, pr);
862 /*
863 * If this is the last slot, free the memory allocated for it.
864 */
865 if (last) {
866 if (prison_service_slots == 0)
867 slots = NULL;
868 else {
869 slots = malloc(sizeof(*slots) * prison_service_slots,
870 M_PRISON, M_WAITOK);
871 }
872 mtx_lock(&pr->pr_mtx);
873 oldslots = pr->pr_slots;
874 /*
875 * We require setting slot to NULL after freeing it,
876 * this way we can check for memory leaks here.
877 */
878 KASSERT(oldslots[psrv->ps_slotno] == NULL,
879 ("Slot %d (service %s, jailid=%d) still contains data?",
880 psrv->ps_slotno, psrv->ps_name, pr->pr_id));
881 if (psrv->ps_slotno > 0) {
882 bcopy(oldslots, slots,
883 sizeof(*slots) * prison_service_slots);
884 }
885 pr->pr_slots = slots;
886 mtx_unlock(&pr->pr_mtx);
887 KASSERT(oldslots != NULL, ("oldslots == NULL"));
888 free(oldslots, M_PRISON);
889 }
890 }
891 sx_sunlock(&allprison_lock);
892 free(psrv, M_PRISON);
893 }
894
895 /*
896 * Function sets data for the given jail in slot assigned for the given
897 * jail service.
898 */
899 void
900 prison_service_data_set(struct prison_service *psrv, struct prison *pr,
901 void *data)
902 {
903
904 mtx_assert(&pr->pr_mtx, MA_OWNED);
905 pr->pr_slots[psrv->ps_slotno] = data;
906 }
907
908 /*
909 * Function clears slots assigned for the given jail service in the given
910 * prison structure and returns current slot data.
911 */
912 void *
913 prison_service_data_del(struct prison_service *psrv, struct prison *pr)
914 {
915 void *data;
916
917 mtx_assert(&pr->pr_mtx, MA_OWNED);
918 data = pr->pr_slots[psrv->ps_slotno];
919 pr->pr_slots[psrv->ps_slotno] = NULL;
920 return (data);
921 }
922
923 /*
924 * Function returns current data from the slot assigned to the given jail
925 * service for the given jail.
926 */
927 void *
928 prison_service_data_get(struct prison_service *psrv, struct prison *pr)
929 {
930
931 mtx_assert(&pr->pr_mtx, MA_OWNED);
932 return (pr->pr_slots[psrv->ps_slotno]);
933 }
934
935 static int
936 sysctl_jail_list(SYSCTL_HANDLER_ARGS)
937 {
938 struct xprison *xp, *sxp;
939 struct prison *pr;
940 int count, error;
941
942 if (jailed(req->td->td_ucred))
943 return (0);
944
945 sx_slock(&allprison_lock);
946 if ((count = prisoncount) == 0) {
947 sx_sunlock(&allprison_lock);
948 return (0);
949 }
950
951 sxp = xp = malloc(sizeof(*xp) * count, M_TEMP, M_WAITOK | M_ZERO);
952
953 LIST_FOREACH(pr, &allprison, pr_list) {
954 xp->pr_version = XPRISON_VERSION;
955 xp->pr_id = pr->pr_id;
956 xp->pr_ip = pr->pr_ip;
957 strlcpy(xp->pr_path, pr->pr_path, sizeof(xp->pr_path));
958 mtx_lock(&pr->pr_mtx);
959 strlcpy(xp->pr_host, pr->pr_host, sizeof(xp->pr_host));
960 mtx_unlock(&pr->pr_mtx);
961 xp++;
962 }
963 sx_sunlock(&allprison_lock);
964
965 error = SYSCTL_OUT(req, sxp, sizeof(*sxp) * count);
966 free(sxp, M_TEMP);
967 return (error);
968 }
969
970 SYSCTL_OID(_security_jail, OID_AUTO, list, CTLTYPE_STRUCT | CTLFLAG_RD,
971 NULL, 0, sysctl_jail_list, "S", "List of active jails");
972
973 static int
974 sysctl_jail_jailed(SYSCTL_HANDLER_ARGS)
975 {
976 int error, injail;
977
978 injail = jailed(req->td->td_ucred);
979 error = SYSCTL_OUT(req, &injail, sizeof(injail));
980
981 return (error);
982 }
983 SYSCTL_PROC(_security_jail, OID_AUTO, jailed, CTLTYPE_INT | CTLFLAG_RD,
984 NULL, 0, sysctl_jail_jailed, "I", "Process in jail?");
Cache object: 5e068a7d8accadd3e4d4189e02fab0d6
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