kern_jail.c revision 167354 
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: head/sys/kern/kern_jail.c 167354 2007-03-09 05:22:10Z pjd $");
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/namei.h>
29#include <sys/mount.h>
30#include <sys/queue.h>
31#include <sys/socket.h>
32#include <sys/syscallsubr.h>
33#include <sys/sysctl.h>
34#include <sys/vnode.h>
35#include <net/if.h>
36#include <netinet/in.h>
37
38#include <security/mac/mac_framework.h>
39
40MALLOC_DEFINE(M_PRISON, "prison", "Prison structures");
41
42SYSCTL_NODE(_security, OID_AUTO, jail, CTLFLAG_RW, 0,
43    "Jail rules");
44
45int	jail_set_hostname_allowed = 1;
46SYSCTL_INT(_security_jail, OID_AUTO, set_hostname_allowed, CTLFLAG_RW,
47    &jail_set_hostname_allowed, 0,
48    "Processes in jail can set their hostnames");
49
50int	jail_socket_unixiproute_only = 1;
51SYSCTL_INT(_security_jail, OID_AUTO, socket_unixiproute_only, CTLFLAG_RW,
52    &jail_socket_unixiproute_only, 0,
53    "Processes in jail are limited to creating UNIX/IPv4/route sockets only");
54
55int	jail_sysvipc_allowed = 0;
56SYSCTL_INT(_security_jail, OID_AUTO, sysvipc_allowed, CTLFLAG_RW,
57    &jail_sysvipc_allowed, 0,
58    "Processes in jail can use System V IPC primitives");
59
60static int jail_enforce_statfs = 2;
61SYSCTL_INT(_security_jail, OID_AUTO, enforce_statfs, CTLFLAG_RW,
62    &jail_enforce_statfs, 0,
63    "Processes in jail cannot see all mounted file systems");
64
65int	jail_allow_raw_sockets = 0;
66SYSCTL_INT(_security_jail, OID_AUTO, allow_raw_sockets, CTLFLAG_RW,
67    &jail_allow_raw_sockets, 0,
68    "Prison root can create raw sockets");
69
70int	jail_chflags_allowed = 0;
71SYSCTL_INT(_security_jail, OID_AUTO, chflags_allowed, CTLFLAG_RW,
72    &jail_chflags_allowed, 0,
73    "Processes in jail can alter system file flags");
74
75/* allprison, lastprid, and prisoncount are protected by allprison_mtx. */
76struct	prisonlist allprison;
77struct	mtx allprison_mtx;
78int	lastprid = 0;
79int	prisoncount = 0;
80
81static void		 init_prison(void *);
82static void		 prison_complete(void *context, int pending);
83static struct prison	*prison_find(int);
84static int		 sysctl_jail_list(SYSCTL_HANDLER_ARGS);
85
86static void
87init_prison(void *data __unused)
88{
89
90	mtx_init(&allprison_mtx, "allprison", NULL, MTX_DEF);
91	LIST_INIT(&allprison);
92}
93
94SYSINIT(prison, SI_SUB_INTRINSIC, SI_ORDER_ANY, init_prison, NULL);
95
96/*
97 * struct jail_args {
98 *	struct jail *jail;
99 * };
100 */
101int
102jail(struct thread *td, struct jail_args *uap)
103{
104	struct nameidata nd;
105	struct prison *pr, *tpr;
106	struct jail j;
107	struct jail_attach_args jaa;
108	int vfslocked, error, tryprid;
109
110	error = copyin(uap->jail, &j, sizeof(j));
111	if (error)
112		return (error);
113	if (j.version != 0)
114		return (EINVAL);
115
116	MALLOC(pr, struct prison *, sizeof(*pr), M_PRISON, M_WAITOK | M_ZERO);
117	mtx_init(&pr->pr_mtx, "jail mutex", NULL, MTX_DEF);
118	pr->pr_ref = 1;
119	error = copyinstr(j.path, &pr->pr_path, sizeof(pr->pr_path), 0);
120	if (error)
121		goto e_killmtx;
122	NDINIT(&nd, LOOKUP, MPSAFE | FOLLOW | LOCKLEAF, UIO_SYSSPACE,
123	    pr->pr_path, td);
124	error = namei(&nd);
125	if (error)
126		goto e_killmtx;
127	vfslocked = NDHASGIANT(&nd);
128	pr->pr_root = nd.ni_vp;
129	VOP_UNLOCK(nd.ni_vp, 0, td);
130	NDFREE(&nd, NDF_ONLY_PNBUF);
131	VFS_UNLOCK_GIANT(vfslocked);
132	error = copyinstr(j.hostname, &pr->pr_host, sizeof(pr->pr_host), 0);
133	if (error)
134		goto e_dropvnref;
135	pr->pr_ip = j.ip_number;
136	pr->pr_linux = NULL;
137	pr->pr_securelevel = securelevel;
138
139	/* Determine next pr_id and add prison to allprison list. */
140	mtx_lock(&allprison_mtx);
141	tryprid = lastprid + 1;
142	if (tryprid == JAIL_MAX)
143		tryprid = 1;
144next:
145	LIST_FOREACH(tpr, &allprison, pr_list) {
146		if (tpr->pr_id == tryprid) {
147			tryprid++;
148			if (tryprid == JAIL_MAX) {
149				mtx_unlock(&allprison_mtx);
150				error = EAGAIN;
151				goto e_dropvnref;
152			}
153			goto next;
154		}
155	}
156	pr->pr_id = jaa.jid = lastprid = tryprid;
157	LIST_INSERT_HEAD(&allprison, pr, pr_list);
158	prisoncount++;
159	mtx_unlock(&allprison_mtx);
160
161	error = jail_attach(td, &jaa);
162	if (error)
163		goto e_dropprref;
164	mtx_lock(&pr->pr_mtx);
165	pr->pr_ref--;
166	mtx_unlock(&pr->pr_mtx);
167	td->td_retval[0] = jaa.jid;
168	return (0);
169e_dropprref:
170	mtx_lock(&allprison_mtx);
171	LIST_REMOVE(pr, pr_list);
172	prisoncount--;
173	mtx_unlock(&allprison_mtx);
174e_dropvnref:
175	vfslocked = VFS_LOCK_GIANT(pr->pr_root->v_mount);
176	vrele(pr->pr_root);
177	VFS_UNLOCK_GIANT(vfslocked);
178e_killmtx:
179	mtx_destroy(&pr->pr_mtx);
180	FREE(pr, M_PRISON);
181	return (error);
182}
183
184/*
185 * struct jail_attach_args {
186 *	int jid;
187 * };
188 */
189int
190jail_attach(struct thread *td, struct jail_attach_args *uap)
191{
192	struct proc *p;
193	struct ucred *newcred, *oldcred;
194	struct prison *pr;
195	int vfslocked, error;
196
197	/*
198	 * XXX: Note that there is a slight race here if two threads
199	 * in the same privileged process attempt to attach to two
200	 * different jails at the same time.  It is important for
201	 * user processes not to do this, or they might end up with
202	 * a process root from one prison, but attached to the jail
203	 * of another.
204	 */
205	error = priv_check(td, PRIV_JAIL_ATTACH);
206	if (error)
207		return (error);
208
209	p = td->td_proc;
210	mtx_lock(&allprison_mtx);
211	pr = prison_find(uap->jid);
212	if (pr == NULL) {
213		mtx_unlock(&allprison_mtx);
214		return (EINVAL);
215	}
216	pr->pr_ref++;
217	mtx_unlock(&pr->pr_mtx);
218	mtx_unlock(&allprison_mtx);
219
220	vfslocked = VFS_LOCK_GIANT(pr->pr_root->v_mount);
221	vn_lock(pr->pr_root, LK_EXCLUSIVE | LK_RETRY, td);
222	if ((error = change_dir(pr->pr_root, td)) != 0)
223		goto e_unlock;
224#ifdef MAC
225	if ((error = mac_check_vnode_chroot(td->td_ucred, pr->pr_root)))
226		goto e_unlock;
227#endif
228	VOP_UNLOCK(pr->pr_root, 0, td);
229	change_root(pr->pr_root, td);
230	VFS_UNLOCK_GIANT(vfslocked);
231
232	newcred = crget();
233	PROC_LOCK(p);
234	oldcred = p->p_ucred;
235	setsugid(p);
236	crcopy(newcred, oldcred);
237	newcred->cr_prison = pr;
238	p->p_ucred = newcred;
239	PROC_UNLOCK(p);
240	crfree(oldcred);
241	return (0);
242e_unlock:
243	VOP_UNLOCK(pr->pr_root, 0, td);
244	VFS_UNLOCK_GIANT(vfslocked);
245	mtx_lock(&pr->pr_mtx);
246	pr->pr_ref--;
247	mtx_unlock(&pr->pr_mtx);
248	return (error);
249}
250
251/*
252 * Returns a locked prison instance, or NULL on failure.
253 */
254static struct prison *
255prison_find(int prid)
256{
257	struct prison *pr;
258
259	mtx_assert(&allprison_mtx, MA_OWNED);
260	LIST_FOREACH(pr, &allprison, pr_list) {
261		if (pr->pr_id == prid) {
262			mtx_lock(&pr->pr_mtx);
263			return (pr);
264		}
265	}
266	return (NULL);
267}
268
269void
270prison_free(struct prison *pr)
271{
272
273	mtx_lock(&allprison_mtx);
274	mtx_lock(&pr->pr_mtx);
275	pr->pr_ref--;
276	if (pr->pr_ref == 0) {
277		LIST_REMOVE(pr, pr_list);
278		mtx_unlock(&pr->pr_mtx);
279		prisoncount--;
280		mtx_unlock(&allprison_mtx);
281
282		TASK_INIT(&pr->pr_task, 0, prison_complete, pr);
283		taskqueue_enqueue(taskqueue_thread, &pr->pr_task);
284		return;
285	}
286	mtx_unlock(&pr->pr_mtx);
287	mtx_unlock(&allprison_mtx);
288}
289
290static void
291prison_complete(void *context, int pending)
292{
293	struct prison *pr;
294	int vfslocked;
295
296	pr = (struct prison *)context;
297
298	vfslocked = VFS_LOCK_GIANT(pr->pr_root->v_mount);
299	vrele(pr->pr_root);
300	VFS_UNLOCK_GIANT(vfslocked);
301
302	mtx_destroy(&pr->pr_mtx);
303	if (pr->pr_linux != NULL)
304		FREE(pr->pr_linux, M_PRISON);
305	FREE(pr, M_PRISON);
306}
307
308void
309prison_hold(struct prison *pr)
310{
311
312	mtx_lock(&pr->pr_mtx);
313	pr->pr_ref++;
314	mtx_unlock(&pr->pr_mtx);
315}
316
317u_int32_t
318prison_getip(struct ucred *cred)
319{
320
321	return (cred->cr_prison->pr_ip);
322}
323
324int
325prison_ip(struct ucred *cred, int flag, u_int32_t *ip)
326{
327	u_int32_t tmp;
328
329	if (!jailed(cred))
330		return (0);
331	if (flag)
332		tmp = *ip;
333	else
334		tmp = ntohl(*ip);
335	if (tmp == INADDR_ANY) {
336		if (flag)
337			*ip = cred->cr_prison->pr_ip;
338		else
339			*ip = htonl(cred->cr_prison->pr_ip);
340		return (0);
341	}
342	if (tmp == INADDR_LOOPBACK) {
343		if (flag)
344			*ip = cred->cr_prison->pr_ip;
345		else
346			*ip = htonl(cred->cr_prison->pr_ip);
347		return (0);
348	}
349	if (cred->cr_prison->pr_ip != tmp)
350		return (1);
351	return (0);
352}
353
354void
355prison_remote_ip(struct ucred *cred, int flag, u_int32_t *ip)
356{
357	u_int32_t tmp;
358
359	if (!jailed(cred))
360		return;
361	if (flag)
362		tmp = *ip;
363	else
364		tmp = ntohl(*ip);
365	if (tmp == INADDR_LOOPBACK) {
366		if (flag)
367			*ip = cred->cr_prison->pr_ip;
368		else
369			*ip = htonl(cred->cr_prison->pr_ip);
370		return;
371	}
372	return;
373}
374
375int
376prison_if(struct ucred *cred, struct sockaddr *sa)
377{
378	struct sockaddr_in *sai;
379	int ok;
380
381	sai = (struct sockaddr_in *)sa;
382	if ((sai->sin_family != AF_INET) && jail_socket_unixiproute_only)
383		ok = 1;
384	else if (sai->sin_family != AF_INET)
385		ok = 0;
386	else if (cred->cr_prison->pr_ip != ntohl(sai->sin_addr.s_addr))
387		ok = 1;
388	else
389		ok = 0;
390	return (ok);
391}
392
393/*
394 * Return 0 if jails permit p1 to frob p2, otherwise ESRCH.
395 */
396int
397prison_check(struct ucred *cred1, struct ucred *cred2)
398{
399
400	if (jailed(cred1)) {
401		if (!jailed(cred2))
402			return (ESRCH);
403		if (cred2->cr_prison != cred1->cr_prison)
404			return (ESRCH);
405	}
406
407	return (0);
408}
409
410/*
411 * Return 1 if the passed credential is in a jail, otherwise 0.
412 */
413int
414jailed(struct ucred *cred)
415{
416
417	return (cred->cr_prison != NULL);
418}
419
420/*
421 * Return the correct hostname for the passed credential.
422 */
423void
424getcredhostname(struct ucred *cred, char *buf, size_t size)
425{
426
427	if (jailed(cred)) {
428		mtx_lock(&cred->cr_prison->pr_mtx);
429		strlcpy(buf, cred->cr_prison->pr_host, size);
430		mtx_unlock(&cred->cr_prison->pr_mtx);
431	} else
432		strlcpy(buf, hostname, size);
433}
434
435/*
436 * Determine whether the subject represented by cred can "see"
437 * status of a mount point.
438 * Returns: 0 for permitted, ENOENT otherwise.
439 * XXX: This function should be called cr_canseemount() and should be
440 *      placed in kern_prot.c.
441 */
442int
443prison_canseemount(struct ucred *cred, struct mount *mp)
444{
445	struct prison *pr;
446	struct statfs *sp;
447	size_t len;
448
449	if (!jailed(cred) || jail_enforce_statfs == 0)
450		return (0);
451	pr = cred->cr_prison;
452	if (pr->pr_root->v_mount == mp)
453		return (0);
454	if (jail_enforce_statfs == 2)
455		return (ENOENT);
456	/*
457	 * If jail's chroot directory is set to "/" we should be able to see
458	 * all mount-points from inside a jail.
459	 * This is ugly check, but this is the only situation when jail's
460	 * directory ends with '/'.
461	 */
462	if (strcmp(pr->pr_path, "/") == 0)
463		return (0);
464	len = strlen(pr->pr_path);
465	sp = &mp->mnt_stat;
466	if (strncmp(pr->pr_path, sp->f_mntonname, len) != 0)
467		return (ENOENT);
468	/*
469	 * Be sure that we don't have situation where jail's root directory
470	 * is "/some/path" and mount point is "/some/pathpath".
471	 */
472	if (sp->f_mntonname[len] != '\0' && sp->f_mntonname[len] != '/')
473		return (ENOENT);
474	return (0);
475}
476
477void
478prison_enforce_statfs(struct ucred *cred, struct mount *mp, struct statfs *sp)
479{
480	char jpath[MAXPATHLEN];
481	struct prison *pr;
482	size_t len;
483
484	if (!jailed(cred) || jail_enforce_statfs == 0)
485		return;
486	pr = cred->cr_prison;
487	if (prison_canseemount(cred, mp) != 0) {
488		bzero(sp->f_mntonname, sizeof(sp->f_mntonname));
489		strlcpy(sp->f_mntonname, "[restricted]",
490		    sizeof(sp->f_mntonname));
491		return;
492	}
493	if (pr->pr_root->v_mount == mp) {
494		/*
495		 * Clear current buffer data, so we are sure nothing from
496		 * the valid path left there.
497		 */
498		bzero(sp->f_mntonname, sizeof(sp->f_mntonname));
499		*sp->f_mntonname = '/';
500		return;
501	}
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	 */
506	if (strcmp(pr->pr_path, "/") == 0)
507		return;
508	len = strlen(pr->pr_path);
509	strlcpy(jpath, sp->f_mntonname + len, sizeof(jpath));
510	/*
511	 * Clear current buffer data, so we are sure nothing from
512	 * the valid path left there.
513	 */
514	bzero(sp->f_mntonname, sizeof(sp->f_mntonname));
515	if (*jpath == '\0') {
516		/* Should never happen. */
517		*sp->f_mntonname = '/';
518	} else {
519		strlcpy(sp->f_mntonname, jpath, sizeof(sp->f_mntonname));
520	}
521}
522
523/*
524 * Check with permission for a specific privilege is granted within jail.  We
525 * have a specific list of accepted privileges; the rest are denied.
526 */
527int
528prison_priv_check(struct ucred *cred, int priv)
529{
530
531	if (!jailed(cred))
532		return (0);
533
534	switch (priv) {
535
536		/*
537		 * Allow ktrace privileges for root in jail.
538		 */
539	case PRIV_KTRACE:
540
541#if 0
542		/*
543		 * Allow jailed processes to configure audit identity and
544		 * submit audit records (login, etc).  In the future we may
545		 * want to further refine the relationship between audit and
546		 * jail.
547		 */
548	case PRIV_AUDIT_GETAUDIT:
549	case PRIV_AUDIT_SETAUDIT:
550	case PRIV_AUDIT_SUBMIT:
551#endif
552
553		/*
554		 * Allow jailed processes to manipulate process UNIX
555		 * credentials in any way they see fit.
556		 */
557	case PRIV_CRED_SETUID:
558	case PRIV_CRED_SETEUID:
559	case PRIV_CRED_SETGID:
560	case PRIV_CRED_SETEGID:
561	case PRIV_CRED_SETGROUPS:
562	case PRIV_CRED_SETREUID:
563	case PRIV_CRED_SETREGID:
564	case PRIV_CRED_SETRESUID:
565	case PRIV_CRED_SETRESGID:
566
567		/*
568		 * Jail implements visibility constraints already, so allow
569		 * jailed root to override uid/gid-based constraints.
570		 */
571	case PRIV_SEEOTHERGIDS:
572	case PRIV_SEEOTHERUIDS:
573
574		/*
575		 * Jail implements inter-process debugging limits already, so
576		 * allow jailed root various debugging privileges.
577		 */
578	case PRIV_DEBUG_DIFFCRED:
579	case PRIV_DEBUG_SUGID:
580	case PRIV_DEBUG_UNPRIV:
581
582		/*
583		 * Allow jail to set various resource limits and login
584		 * properties, and for now, exceed process resource limits.
585		 */
586	case PRIV_PROC_LIMIT:
587	case PRIV_PROC_SETLOGIN:
588	case PRIV_PROC_SETRLIMIT:
589
590		/*
591		 * System V and POSIX IPC privileges are granted in jail.
592		 */
593	case PRIV_IPC_READ:
594	case PRIV_IPC_WRITE:
595	case PRIV_IPC_ADMIN:
596	case PRIV_IPC_MSGSIZE:
597	case PRIV_MQ_ADMIN:
598
599		/*
600		 * Jail implements its own inter-process limits, so allow
601		 * root processes in jail to change scheduling on other
602		 * processes in the same jail.  Likewise for signalling.
603		 */
604	case PRIV_SCHED_DIFFCRED:
605	case PRIV_SIGNAL_DIFFCRED:
606	case PRIV_SIGNAL_SUGID:
607
608		/*
609		 * Allow jailed processes to write to sysctls marked as jail
610		 * writable.
611		 */
612	case PRIV_SYSCTL_WRITEJAIL:
613
614		/*
615		 * Allow root in jail to manage a variety of quota
616		 * properties.  These should likely be conditional on a
617		 * configuration option.
618		 */
619	case PRIV_VFS_GETQUOTA:
620	case PRIV_VFS_SETQUOTA:
621
622		/*
623		 * Since Jail relies on chroot() to implement file system
624		 * protections, grant many VFS privileges to root in jail.
625		 * Be careful to exclude mount-related and NFS-related
626		 * privileges.
627		 */
628	case PRIV_VFS_READ:
629	case PRIV_VFS_WRITE:
630	case PRIV_VFS_ADMIN:
631	case PRIV_VFS_EXEC:
632	case PRIV_VFS_LOOKUP:
633	case PRIV_VFS_BLOCKRESERVE:	/* XXXRW: Slightly surprising. */
634	case PRIV_VFS_CHFLAGS_DEV:
635	case PRIV_VFS_CHOWN:
636	case PRIV_VFS_CHROOT:
637	case PRIV_VFS_RETAINSUGID:
638	case PRIV_VFS_FCHROOT:
639	case PRIV_VFS_LINK:
640	case PRIV_VFS_SETGID:
641	case PRIV_VFS_STICKYFILE:
642		return (0);
643
644		/*
645		 * Depending on the global setting, allow privilege of
646		 * setting system flags.
647		 */
648	case PRIV_VFS_SYSFLAGS:
649		if (jail_chflags_allowed)
650			return (0);
651		else
652			return (EPERM);
653
654		/*
655		 * Allow jailed root to bind reserved ports.
656		 */
657	case PRIV_NETINET_RESERVEDPORT:
658		return (0);
659
660		/*
661		 * Conditionally allow creating raw sockets in jail.
662		 */
663	case PRIV_NETINET_RAW:
664		if (jail_allow_raw_sockets)
665			return (0);
666		else
667			return (EPERM);
668
669		/*
670		 * Since jail implements its own visibility limits on netstat
671		 * sysctls, allow getcred.  This allows identd to work in
672		 * jail.
673		 */
674	case PRIV_NETINET_GETCRED:
675		return (0);
676
677	default:
678		/*
679		 * In all remaining cases, deny the privilege request.  This
680		 * includes almost all network privileges, many system
681		 * configuration privileges.
682		 */
683		return (EPERM);
684	}
685}
686
687static int
688sysctl_jail_list(SYSCTL_HANDLER_ARGS)
689{
690	struct xprison *xp, *sxp;
691	struct prison *pr;
692	int count, error;
693
694	if (jailed(req->td->td_ucred))
695		return (0);
696retry:
697	mtx_lock(&allprison_mtx);
698	count = prisoncount;
699	mtx_unlock(&allprison_mtx);
700
701	if (count == 0)
702		return (0);
703
704	sxp = xp = malloc(sizeof(*xp) * count, M_TEMP, M_WAITOK | M_ZERO);
705	mtx_lock(&allprison_mtx);
706	if (count != prisoncount) {
707		mtx_unlock(&allprison_mtx);
708		free(sxp, M_TEMP);
709		goto retry;
710	}
711
712	LIST_FOREACH(pr, &allprison, pr_list) {
713		mtx_lock(&pr->pr_mtx);
714		xp->pr_version = XPRISON_VERSION;
715		xp->pr_id = pr->pr_id;
716		strlcpy(xp->pr_path, pr->pr_path, sizeof(xp->pr_path));
717		strlcpy(xp->pr_host, pr->pr_host, sizeof(xp->pr_host));
718		xp->pr_ip = pr->pr_ip;
719		mtx_unlock(&pr->pr_mtx);
720		xp++;
721	}
722	mtx_unlock(&allprison_mtx);
723
724	error = SYSCTL_OUT(req, sxp, sizeof(*sxp) * count);
725	free(sxp, M_TEMP);
726	return (error);
727}
728
729SYSCTL_OID(_security_jail, OID_AUTO, list, CTLTYPE_STRUCT | CTLFLAG_RD,
730    NULL, 0, sysctl_jail_list, "S", "List of active jails");
731
732static int
733sysctl_jail_jailed(SYSCTL_HANDLER_ARGS)
734{
735	int error, injail;
736
737	injail = jailed(req->td->td_ucred);
738	error = SYSCTL_OUT(req, &injail, sizeof(injail));
739
740	return (error);
741}
742SYSCTL_PROC(_security_jail, OID_AUTO, jailed, CTLTYPE_INT | CTLFLAG_RD,
743    NULL, 0, sysctl_jail_jailed, "I", "Process in jail?");
744