xref: /freebsd/sys/kern/kern_jail.c (revision 10a3562a019b4eaaa0f5c50a15d739c43e41e8e7)
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause
3  *
4  * Copyright (c) 1999 Poul-Henning Kamp.
5  * Copyright (c) 2008 Bjoern A. Zeeb.
6  * Copyright (c) 2009 James Gritton.
7  * All rights reserved.
8  *
9  * Redistribution and use in source and binary forms, with or without
10  * modification, are permitted provided that the following conditions
11  * are met:
12  * 1. Redistributions of source code must retain the above copyright
13  *    notice, this list of conditions and the following disclaimer.
14  * 2. Redistributions in binary form must reproduce the above copyright
15  *    notice, this list of conditions and the following disclaimer in the
16  *    documentation and/or other materials provided with the distribution.
17  *
18  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
19  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
20  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
21  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
22  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
23  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
24  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
25  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
26  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
27  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
28  * SUCH DAMAGE.
29  */
30 
31 #include <sys/cdefs.h>
32 #include "opt_ddb.h"
33 #include "opt_inet.h"
34 #include "opt_inet6.h"
35 #include "opt_nfs.h"
36 
37 #include <sys/param.h>
38 #include <sys/types.h>
39 #include <sys/ctype.h>
40 #include <sys/kernel.h>
41 #include <sys/systm.h>
42 #include <sys/errno.h>
43 #include <sys/file.h>
44 #include <sys/sysproto.h>
45 #include <sys/malloc.h>
46 #include <sys/osd.h>
47 #include <sys/priv.h>
48 #include <sys/proc.h>
49 #include <sys/epoch.h>
50 #include <sys/event.h>
51 #include <sys/taskqueue.h>
52 #include <sys/fcntl.h>
53 #include <sys/jail.h>
54 #include <sys/jaildesc.h>
55 #include <sys/linker.h>
56 #include <sys/lock.h>
57 #include <sys/mman.h>
58 #include <sys/mutex.h>
59 #include <sys/racct.h>
60 #include <sys/rctl.h>
61 #include <sys/refcount.h>
62 #include <sys/sx.h>
63 #include <sys/sysent.h>
64 #include <sys/namei.h>
65 #include <sys/mount.h>
66 #include <sys/queue.h>
67 #include <sys/socket.h>
68 #include <sys/syscallsubr.h>
69 #include <sys/sysctl.h>
70 #include <sys/uuid.h>
71 #include <sys/vnode.h>
72 
73 #include <net/if.h>
74 #include <net/vnet.h>
75 
76 #include <netinet/in.h>
77 
78 #ifdef DDB
79 #include <ddb/ddb.h>
80 #endif /* DDB */
81 
82 #include <security/mac/mac_framework.h>
83 #include <security/mac/mac_policy.h>
84 #include <security/mac/mac_syscalls.h>
85 
86 #define	PRISON0_HOSTUUID_MODULE	"hostuuid"
87 
88 MALLOC_DEFINE(M_PRISON, "prison", "Prison structures");
89 #ifdef RACCT
90 static MALLOC_DEFINE(M_PRISON_RACCT, "prison_racct", "Prison racct structures");
91 #endif
92 
93 /* Keep struct prison prison0 and some code in kern_jail_set() readable. */
94 #ifdef INET
95 #ifdef INET6
96 #define	_PR_IP_SADDRSEL	PR_IP4_SADDRSEL|PR_IP6_SADDRSEL
97 #else
98 #define	_PR_IP_SADDRSEL	PR_IP4_SADDRSEL
99 #endif
100 #else /* !INET */
101 #ifdef INET6
102 #define	_PR_IP_SADDRSEL	PR_IP6_SADDRSEL
103 #else
104 #define	_PR_IP_SADDRSEL	0
105 #endif
106 #endif
107 
108 /* prison0 describes what is "real" about the system. */
109 struct prison prison0 = {
110 	.pr_id		= 0,
111 	.pr_name	= "0",
112 	.pr_ref		= 1,
113 	.pr_uref	= 1,
114 	.pr_path	= "/",
115 	.pr_securelevel	= -1,
116 	.pr_devfs_rsnum = 0,
117 	.pr_state	= PRISON_STATE_ALIVE,
118 	.pr_childmax	= JAIL_MAX,
119 	.pr_hostuuid	= DEFAULT_HOSTUUID,
120 	.pr_children	= LIST_HEAD_INITIALIZER(prison0.pr_children),
121 #ifdef VIMAGE
122 	.pr_flags	= PR_HOST|PR_VNET|_PR_IP_SADDRSEL,
123 #else
124 	.pr_flags	= PR_HOST|_PR_IP_SADDRSEL,
125 #endif
126 	.pr_allow	= PR_ALLOW_PRISON0,
127 };
128 _Static_assert((PR_ALLOW_PRISON0 & ~PR_ALLOW_ALL_STATIC) == 0,
129     "Bits enabled in PR_ALLOW_PRISON0 that are not statically reserved");
130 
131 MTX_SYSINIT(prison0, &prison0.pr_mtx, "jail mutex", MTX_DEF);
132 
133 struct bool_flags {
134 	const char	*name;
135 	const char	*noname;
136 	volatile u_int	 flag;
137 };
138 struct jailsys_flags {
139 	const char	*name;
140 	unsigned	 disable;
141 	unsigned	 new;
142 };
143 
144 /*
145  * Handle jail teardown in a dedicated thread to avoid deadlocks from
146  * vnet_destroy().
147  */
148 TASKQUEUE_DEFINE_THREAD(jail_remove);
149 
150 /* allprison, allprison_racct and lastprid are protected by allprison_lock. */
151 struct	sx allprison_lock;
152 SX_SYSINIT(allprison_lock, &allprison_lock, "allprison");
153 struct	prisonlist allprison = TAILQ_HEAD_INITIALIZER(allprison);
154 LIST_HEAD(, prison_racct) allprison_racct;
155 int	lastprid = 0;
156 int	lastdeadid = 0;
157 
158 static int get_next_prid(struct prison **insprp);
159 static int get_next_deadid(struct prison **insprp);
160 static int do_jail_attach(struct thread *td, struct prison *pr, int *drflagsp);
161 static int prison_attach_thread_single(struct thread *td);
162 static void prison_attach_thread_single_end(struct thread *td);
163 static void prison_complete(void *context, int pending);
164 static void prison_deref(struct prison *pr, int flags);
165 static void prison_deref_kill(struct prison *pr, struct prisonlist *freeprison);
166 static int prison_lock_xlock(struct prison *pr, int flags);
167 static void prison_cleanup_locked(struct prison *pr);
168 static void prison_cleanup_unlocked(struct prison *pr);
169 static void prison_free_not_last(struct prison *pr);
170 static void prison_proc_free_not_last(struct prison *pr);
171 static void prison_proc_relink(struct prison *opr, struct prison *npr,
172     struct proc *p);
173 static void prison_set_allow_locked(struct prison *pr, unsigned flag,
174     int enable);
175 static char *prison_path(struct prison *pr1, struct prison *pr2);
176 #ifdef RACCT
177 static void prison_racct_attach(struct prison *pr);
178 static void prison_racct_modify(struct prison *pr);
179 static void prison_racct_detach(struct prison *pr);
180 #endif
181 static void prison_knote(struct prison *pr, long hint);
182 
183 /* Flags for prison_deref */
184 #define	PD_DEREF	0x01	/* Decrement pr_ref */
185 #define	PD_DEUREF	0x02	/* Decrement pr_uref */
186 #define	PD_KILL		0x04	/* Remove jail, kill processes, etc */
187 #define	PD_LOCKED	0x10	/* pr_mtx is held */
188 #define	PD_LIST_SLOCKED	0x20	/* allprison_lock is held shared */
189 #define	PD_LIST_XLOCKED	0x40	/* allprison_lock is held exclusive */
190 #define PD_OP_FLAGS	0x07	/* Operation flags */
191 #define PD_LOCK_FLAGS	0x70	/* Lock status flags */
192 
193 /*
194  * Parameter names corresponding to PR_* flag values.  Size values are for kvm
195  * as we cannot figure out the size of a sparse array, or an array without a
196  * terminating entry.
197  */
198 static struct bool_flags pr_flag_bool[] = {
199 	{JAIL_PARAM_PERSIST, JAIL_PARAM_NOPERSIST, PR_PERSIST},
200 #ifdef INET
201 	{JAIL_PARAM_IP4_SADDRSEL, JAIL_PARAM_IP4_NOSADDRSEL, PR_IP4_SADDRSEL},
202 #endif
203 #ifdef INET6
204 	{JAIL_PARAM_IP6_SADDRSEL, JAIL_PARAM_IP6_NOSADDRSEL, PR_IP6_SADDRSEL},
205 #endif
206 };
207 const size_t pr_flag_bool_size = sizeof(pr_flag_bool);
208 
209 static struct jailsys_flags pr_flag_jailsys[] = {
210 	{JAIL_PARAM_HOST, 0, PR_HOST},
211 #ifdef VIMAGE
212 	{JAIL_PARAM_VNET, 0, PR_VNET},
213 #endif
214 #ifdef INET
215 	{JAIL_PARAM_IP4, PR_IP4_USER, PR_IP4_USER},
216 #endif
217 #ifdef INET6
218 	{JAIL_PARAM_IP6, PR_IP6_USER, PR_IP6_USER},
219 #endif
220 };
221 const size_t pr_flag_jailsys_size = sizeof(pr_flag_jailsys);
222 
223 /*
224  * Make this array full-size so dynamic parameters can be added.
225  * It is protected by prison0.mtx, but lockless reading is allowed
226  * with an atomic check of the flag values.
227  */
228 static struct bool_flags pr_flag_allow[NBBY * NBPW] = {
229 	{JAIL_PARAM_ALLOW_SET_HOSTNAME, JAIL_PARAM_ALLOW_NOSET_HOSTNAME,
230 	 PR_ALLOW_SET_HOSTNAME},
231 	{JAIL_PARAM_ALLOW_SYSVIPC, JAIL_PARAM_ALLOW_NOSYSVIPC,
232 	 PR_ALLOW_SYSVIPC},
233 	{JAIL_PARAM_ALLOW_RAW_SOCKETS, JAIL_PARAM_ALLOW_NORAW_SOCKETS,
234 	 PR_ALLOW_RAW_SOCKETS},
235 	{JAIL_PARAM_ALLOW_CHFLAGS, JAIL_PARAM_ALLOW_NOCHFLAGS,
236 	 PR_ALLOW_CHFLAGS},
237 	{JAIL_PARAM_ALLOW_MOUNT, JAIL_PARAM_ALLOW_NOMOUNT, PR_ALLOW_MOUNT},
238 	{JAIL_PARAM_ALLOW_QUOTAS, JAIL_PARAM_ALLOW_NOQUOTAS, PR_ALLOW_QUOTAS},
239 	{JAIL_PARAM_ALLOW_SOCKET_AF, JAIL_PARAM_ALLOW_NOSOCKET_AF,
240 	 PR_ALLOW_SOCKET_AF},
241 	{JAIL_PARAM_ALLOW_MLOCK, JAIL_PARAM_ALLOW_NOMLOCK, PR_ALLOW_MLOCK},
242 	{JAIL_PARAM_ALLOW_RESERVED_PORTS, JAIL_PARAM_ALLOW_NORESERVED_PORTS,
243 	 PR_ALLOW_RESERVED_PORTS},
244 	{JAIL_PARAM_ALLOW_READ_MSGBUF, JAIL_PARAM_ALLOW_NOREAD_MSGBUF,
245 	 PR_ALLOW_READ_MSGBUF},
246 	{JAIL_PARAM_ALLOW_UNPRIV_DEBUG, JAIL_PARAM_ALLOW_NOUNPRIV_DEBUG,
247 	 PR_ALLOW_UNPRIV_DEBUG},
248 	{JAIL_PARAM_ALLOW_SUSER, JAIL_PARAM_ALLOW_NOSUSER, PR_ALLOW_SUSER},
249 #ifdef VIMAGE
250 	{JAIL_PARAM_ALLOW_NFSD, JAIL_PARAM_ALLOW_NONFSD, PR_ALLOW_NFSD},
251 #endif
252 	{JAIL_PARAM_ALLOW_EXTATTR, JAIL_PARAM_ALLOW_NOEXTATTR,
253 	 PR_ALLOW_EXTATTR},
254 	{JAIL_PARAM_ALLOW_ADJTIME, JAIL_PARAM_ALLOW_NOADJTIME,
255 	 PR_ALLOW_ADJTIME},
256 	{JAIL_PARAM_ALLOW_SETTIME, JAIL_PARAM_ALLOW_NOSETTIME,
257 	 PR_ALLOW_SETTIME},
258 	{JAIL_PARAM_ALLOW_ROUTING, JAIL_PARAM_ALLOW_NOROUTING,
259 	 PR_ALLOW_ROUTING},
260 	{JAIL_PARAM_ALLOW_UNPRIV_PARENT_TAMPER,
261 	    JAIL_PARAM_ALLOW_NOUNPRIV_PARENT_TAMPER,
262 	    PR_ALLOW_UNPRIV_PARENT_TAMPER},
263 #ifdef AUDIT
264 	{JAIL_PARAM_ALLOW_SETAUDIT, JAIL_PARAM_ALLOW_NOSETAUDIT,
265 	 PR_ALLOW_SETAUDIT},
266 #endif
267 };
268 static unsigned pr_allow_all = PR_ALLOW_ALL_STATIC;
269 const size_t pr_flag_allow_size = sizeof(pr_flag_allow);
270 
271 #define	JAIL_DEFAULT_ALLOW		(PR_ALLOW_SET_HOSTNAME | \
272 					 PR_ALLOW_RESERVED_PORTS | \
273 					 PR_ALLOW_UNPRIV_DEBUG | \
274 					 PR_ALLOW_SUSER)
275 #define	JAIL_DEFAULT_ENFORCE_STATFS	2
276 #define	JAIL_DEFAULT_DEVFS_RSNUM	0
277 static unsigned jail_default_allow = JAIL_DEFAULT_ALLOW;
278 static int jail_default_enforce_statfs = JAIL_DEFAULT_ENFORCE_STATFS;
279 static int jail_default_devfs_rsnum = JAIL_DEFAULT_DEVFS_RSNUM;
280 #if defined(INET) || defined(INET6)
281 static unsigned jail_max_af_ips = 255;
282 #endif
283 
284 /*
285  * Initialize the parts of prison0 that can't be static-initialized with
286  * constants.  This is called from proc0_init() after creating thread0 cpuset.
287  */
288 void
289 prison0_init(void)
290 {
291 	uint8_t *file, *data;
292 	size_t size;
293 	char buf[sizeof(prison0.pr_hostuuid)];
294 #ifdef MAC
295 	int error __diagused;
296 #endif
297 	bool valid;
298 
299 #ifdef MAC
300 	error = mac_prison_init(&prison0, M_WAITOK);
301 	MPASS(error == 0);
302 
303 	mtx_unlock(&prison0.pr_mtx);
304 #endif
305 	prison0.pr_cpuset = cpuset_ref(thread0.td_cpuset);
306 	prison0.pr_osreldate = osreldate;
307 	strlcpy(prison0.pr_osrelease, osrelease, sizeof(prison0.pr_osrelease));
308 
309 	/* If we have a preloaded hostuuid, use it. */
310 	file = preload_search_by_type(PRISON0_HOSTUUID_MODULE);
311 	if (file != NULL) {
312 		data = preload_fetch_addr(file);
313 		size = preload_fetch_size(file);
314 		if (data != NULL) {
315 			/*
316 			 * The preloaded data may include trailing whitespace, almost
317 			 * certainly a newline; skip over any whitespace or
318 			 * non-printable characters to be safe.
319 			 */
320 			while (size > 0 && data[size - 1] <= 0x20) {
321 				size--;
322 			}
323 
324 			valid = false;
325 
326 			/*
327 			 * Not NUL-terminated when passed from loader, but
328 			 * validate_uuid requires that due to using sscanf (as
329 			 * does the subsequent strlcpy, since it still reads
330 			 * past the given size to return the true length);
331 			 * bounce to a temporary buffer to fix.
332 			 */
333 			if (size >= sizeof(buf))
334 				goto done;
335 
336 			memcpy(buf, data, size);
337 			buf[size] = '\0';
338 
339 			if (validate_uuid(buf, size, NULL, 0) != 0)
340 				goto done;
341 
342 			valid = true;
343 			(void)strlcpy(prison0.pr_hostuuid, buf,
344 			    sizeof(prison0.pr_hostuuid));
345 
346 done:
347 			if (bootverbose && !valid) {
348 				printf("hostuuid: preload data malformed: '%.*s'\n",
349 				    (int)size, data);
350 			}
351 		}
352 	}
353 	if (bootverbose)
354 		printf("hostuuid: using %s\n", prison0.pr_hostuuid);
355 }
356 
357 /*
358  * struct jail_args {
359  *	struct jail *jail;
360  * };
361  */
362 int
363 sys_jail(struct thread *td, struct jail_args *uap)
364 {
365 	uint32_t version;
366 	int error;
367 	struct jail j;
368 
369 	error = copyin(uap->jail, &version, sizeof(uint32_t));
370 	if (error)
371 		return (error);
372 
373 	switch (version) {
374 	case 0:
375 	{
376 		struct jail_v0 j0;
377 
378 		/* FreeBSD single IPv4 jails. */
379 		bzero(&j, sizeof(struct jail));
380 		error = copyin(uap->jail, &j0, sizeof(struct jail_v0));
381 		if (error)
382 			return (error);
383 		j.version = j0.version;
384 		j.path = j0.path;
385 		j.hostname = j0.hostname;
386 		j.ip4s = htonl(j0.ip_number);	/* jail_v0 is host order */
387 		break;
388 	}
389 
390 	case 1:
391 		/*
392 		 * Version 1 was used by multi-IPv4 jail implementations
393 		 * that never made it into the official kernel.
394 		 */
395 		return (EINVAL);
396 
397 	case 2:	/* JAIL_API_VERSION */
398 		/* FreeBSD multi-IPv4/IPv6,noIP jails. */
399 		error = copyin(uap->jail, &j, sizeof(struct jail));
400 		if (error)
401 			return (error);
402 		break;
403 
404 	default:
405 		/* Sci-Fi jails are not supported, sorry. */
406 		return (EINVAL);
407 	}
408 	return (kern_jail(td, &j));
409 }
410 
411 int
412 kern_jail(struct thread *td, struct jail *j)
413 {
414 	struct iovec optiov[2 * (4 + nitems(pr_flag_allow)
415 #ifdef INET
416 			    + 1
417 #endif
418 #ifdef INET6
419 			    + 1
420 #endif
421 			    )];
422 	struct uio opt;
423 	char *u_path, *u_hostname, *u_name;
424 	struct bool_flags *bf;
425 #ifdef INET
426 	uint32_t ip4s;
427 	struct in_addr *u_ip4;
428 #endif
429 #ifdef INET6
430 	struct in6_addr *u_ip6;
431 #endif
432 	size_t tmplen;
433 	int error, enforce_statfs;
434 
435 	bzero(&optiov, sizeof(optiov));
436 	opt.uio_iov = optiov;
437 	opt.uio_iovcnt = 0;
438 	opt.uio_offset = -1;
439 	opt.uio_resid = -1;
440 	opt.uio_segflg = UIO_SYSSPACE;
441 	opt.uio_rw = UIO_READ;
442 	opt.uio_td = td;
443 
444 	/* Set permissions for top-level jails from sysctls. */
445 	if (!jailed(td->td_ucred)) {
446 		for (bf = pr_flag_allow;
447 		     bf < pr_flag_allow + nitems(pr_flag_allow) &&
448 			atomic_load_int(&bf->flag) != 0;
449 		     bf++) {
450 			optiov[opt.uio_iovcnt].iov_base = __DECONST(char *,
451 			    (jail_default_allow & bf->flag)
452 			    ? bf->name : bf->noname);
453 			optiov[opt.uio_iovcnt].iov_len =
454 			    strlen(optiov[opt.uio_iovcnt].iov_base) + 1;
455 			opt.uio_iovcnt += 2;
456 		}
457 		optiov[opt.uio_iovcnt].iov_base = JAIL_PARAM_ENFORCE_STATFS;
458 		optiov[opt.uio_iovcnt].iov_len = sizeof(JAIL_PARAM_ENFORCE_STATFS);
459 		opt.uio_iovcnt++;
460 		enforce_statfs = jail_default_enforce_statfs;
461 		optiov[opt.uio_iovcnt].iov_base = &enforce_statfs;
462 		optiov[opt.uio_iovcnt].iov_len = sizeof(enforce_statfs);
463 		opt.uio_iovcnt++;
464 	}
465 
466 	tmplen = MAXPATHLEN + MAXHOSTNAMELEN + MAXHOSTNAMELEN;
467 #ifdef INET
468 	ip4s = (j->version == 0) ? 1 : j->ip4s;
469 	if (ip4s > jail_max_af_ips)
470 		return (EINVAL);
471 	tmplen += ip4s * sizeof(struct in_addr);
472 #else
473 	if (j->ip4s > 0)
474 		return (EINVAL);
475 #endif
476 #ifdef INET6
477 	if (j->ip6s > jail_max_af_ips)
478 		return (EINVAL);
479 	tmplen += j->ip6s * sizeof(struct in6_addr);
480 #else
481 	if (j->ip6s > 0)
482 		return (EINVAL);
483 #endif
484 	u_path = malloc(tmplen, M_TEMP, M_WAITOK);
485 	u_hostname = u_path + MAXPATHLEN;
486 	u_name = u_hostname + MAXHOSTNAMELEN;
487 #ifdef INET
488 	u_ip4 = (struct in_addr *)(u_name + MAXHOSTNAMELEN);
489 #endif
490 #ifdef INET6
491 #ifdef INET
492 	u_ip6 = (struct in6_addr *)(u_ip4 + ip4s);
493 #else
494 	u_ip6 = (struct in6_addr *)(u_name + MAXHOSTNAMELEN);
495 #endif
496 #endif
497 	optiov[opt.uio_iovcnt].iov_base = JAIL_PARAM_PATH;
498 	optiov[opt.uio_iovcnt].iov_len = sizeof(JAIL_PARAM_PATH);
499 	opt.uio_iovcnt++;
500 	optiov[opt.uio_iovcnt].iov_base = u_path;
501 	error = copyinstr(j->path, u_path, MAXPATHLEN,
502 	    &optiov[opt.uio_iovcnt].iov_len);
503 	if (error) {
504 		free(u_path, M_TEMP);
505 		return (error);
506 	}
507 	opt.uio_iovcnt++;
508 	optiov[opt.uio_iovcnt].iov_base = JAIL_PARAM_HOST_HOSTNAME;
509 	optiov[opt.uio_iovcnt].iov_len = sizeof(JAIL_PARAM_HOST_HOSTNAME);
510 	opt.uio_iovcnt++;
511 	optiov[opt.uio_iovcnt].iov_base = u_hostname;
512 	error = copyinstr(j->hostname, u_hostname, MAXHOSTNAMELEN,
513 	    &optiov[opt.uio_iovcnt].iov_len);
514 	if (error) {
515 		free(u_path, M_TEMP);
516 		return (error);
517 	}
518 	opt.uio_iovcnt++;
519 	if (j->jailname != NULL) {
520 		optiov[opt.uio_iovcnt].iov_base = JAIL_PARAM_NAME;
521 		optiov[opt.uio_iovcnt].iov_len = sizeof(JAIL_PARAM_NAME);
522 		opt.uio_iovcnt++;
523 		optiov[opt.uio_iovcnt].iov_base = u_name;
524 		error = copyinstr(j->jailname, u_name, MAXHOSTNAMELEN,
525 		    &optiov[opt.uio_iovcnt].iov_len);
526 		if (error) {
527 			free(u_path, M_TEMP);
528 			return (error);
529 		}
530 		opt.uio_iovcnt++;
531 	}
532 #ifdef INET
533 	optiov[opt.uio_iovcnt].iov_base = JAIL_PARAM_IP4_ADDR;
534 	optiov[opt.uio_iovcnt].iov_len = sizeof(JAIL_PARAM_IP4_ADDR);
535 	opt.uio_iovcnt++;
536 	optiov[opt.uio_iovcnt].iov_base = u_ip4;
537 	optiov[opt.uio_iovcnt].iov_len = ip4s * sizeof(struct in_addr);
538 	if (j->version == 0)
539 		u_ip4->s_addr = j->ip4s;
540 	else {
541 		error = copyin(j->ip4, u_ip4, optiov[opt.uio_iovcnt].iov_len);
542 		if (error) {
543 			free(u_path, M_TEMP);
544 			return (error);
545 		}
546 	}
547 	opt.uio_iovcnt++;
548 #endif
549 #ifdef INET6
550 	optiov[opt.uio_iovcnt].iov_base = JAIL_PARAM_IP6_ADDR;
551 	optiov[opt.uio_iovcnt].iov_len = sizeof(JAIL_PARAM_IP6_ADDR);
552 	opt.uio_iovcnt++;
553 	optiov[opt.uio_iovcnt].iov_base = u_ip6;
554 	optiov[opt.uio_iovcnt].iov_len = j->ip6s * sizeof(struct in6_addr);
555 	error = copyin(j->ip6, u_ip6, optiov[opt.uio_iovcnt].iov_len);
556 	if (error) {
557 		free(u_path, M_TEMP);
558 		return (error);
559 	}
560 	opt.uio_iovcnt++;
561 #endif
562 	KASSERT(opt.uio_iovcnt <= nitems(optiov),
563 		("kern_jail: too many iovecs (%d)", opt.uio_iovcnt));
564 	error = kern_jail_set(td, &opt, JAIL_CREATE | JAIL_ATTACH);
565 	free(u_path, M_TEMP);
566 	return (error);
567 }
568 
569 /*
570  * struct jail_set_args {
571  *	struct iovec *iovp;
572  *	unsigned int iovcnt;
573  *	int flags;
574  * };
575  */
576 int
577 sys_jail_set(struct thread *td, struct jail_set_args *uap)
578 {
579 	struct uio *auio;
580 	int error;
581 
582 	/* Check that we have an even number of iovecs. */
583 	if (uap->iovcnt & 1)
584 		return (EINVAL);
585 
586 	error = copyinuio(uap->iovp, uap->iovcnt, &auio);
587 	if (error)
588 		return (error);
589 	error = kern_jail_set(td, auio, uap->flags);
590 	freeuio(auio);
591 	return (error);
592 }
593 
594 #if defined(INET) || defined(INET6)
595 typedef int prison_addr_cmp_t(const void *, const void *);
596 typedef bool prison_addr_valid_t(const void *);
597 static const struct pr_family {
598 	size_t			size;
599 	prison_addr_cmp_t	*cmp;
600 	prison_addr_valid_t	*valid;
601 	int			ip_flag;
602 } pr_families[PR_FAMILY_MAX] = {
603 #ifdef INET
604 	[PR_INET] = {
605 		.size = sizeof(struct in_addr),
606 		.cmp = prison_qcmp_v4,
607 		.valid = prison_valid_v4,
608 		.ip_flag = PR_IP4_USER,
609 	 },
610 #endif
611 #ifdef INET6
612 	[PR_INET6] = {
613 		.size = sizeof(struct in6_addr),
614 		.cmp = prison_qcmp_v6,
615 		.valid = prison_valid_v6,
616 		.ip_flag = PR_IP6_USER,
617 	},
618 #endif
619 };
620 
621 /*
622  * Network address lists (pr_addrs) allocation for jails.  The addresses
623  * are accessed locklessly by the network stack, thus need to be protected by
624  * the network epoch.
625  */
626 struct prison_ip {
627 	struct epoch_context ctx;
628 	uint32_t	ips;
629 #ifdef FUTURE_C
630 	/*
631 	 * XXX Variable-length automatic arrays in union may be
632 	 * supported in future C.
633 	 */
634 	union {
635 		char pr_ip[];
636 		struct in_addr pr_ip4[];
637 		struct in6_addr pr_ip6[];
638 	};
639 #else /* No future C :( */
640 	char pr_ip[];
641 #endif
642 };
643 
644 static char *
645 PR_IP(struct prison_ip *pip, const pr_family_t af, int idx)
646 {
647 	MPASS(pip);
648 	MPASS(af < PR_FAMILY_MAX);
649 	MPASS(idx >= 0 && idx < pip->ips);
650 
651 	return (pip->pr_ip + pr_families[af].size * idx);
652 }
653 
654 static struct prison_ip *
655 prison_ip_alloc(const pr_family_t af, uint32_t cnt, int flags)
656 {
657 	struct prison_ip *pip;
658 
659 	pip = malloc(sizeof(struct prison_ip) + cnt * pr_families[af].size,
660 	    M_PRISON, flags);
661 	if (pip != NULL)
662 		pip->ips = cnt;
663 	return (pip);
664 }
665 
666 /*
667  * Allocate and copyin user supplied address list, sorting and validating.
668  * kern_jail_set() helper.
669  */
670 static struct prison_ip *
671 prison_ip_copyin(const pr_family_t af, void *op, uint32_t cnt)
672 {
673 	prison_addr_cmp_t *const cmp = pr_families[af].cmp;
674 	const size_t size = pr_families[af].size;
675 	struct prison_ip *pip;
676 
677 	pip = prison_ip_alloc(af, cnt, M_WAITOK);
678 	bcopy(op, pip->pr_ip, cnt * size);
679 	/*
680 	 * IP addresses are all sorted but ip[0] to preserve
681 	 * the primary IP address as given from userland.
682 	 * This special IP is used for unbound outgoing
683 	 * connections as well for "loopback" traffic in case
684 	 * source address selection cannot find any more fitting
685 	 * address to connect from.
686 	 */
687 	if (cnt > 1)
688 		qsort(PR_IP(pip, af, 1), cnt - 1, size, cmp);
689 	/*
690 	 * Check for duplicate addresses and do some simple
691 	 * zero and broadcast checks. If users give other bogus
692 	 * addresses it is their problem.
693 	 */
694 	for (int i = 0; i < cnt; i++) {
695 		if (!pr_families[af].valid(PR_IP(pip, af, i))) {
696 			free(pip, M_PRISON);
697 			return (NULL);
698 		}
699 		if (i + 1 < cnt &&
700 		    (cmp(PR_IP(pip, af, 0), PR_IP(pip, af, i + 1)) == 0 ||
701 		     cmp(PR_IP(pip, af, i), PR_IP(pip, af, i + 1)) == 0)) {
702 			free(pip, M_PRISON);
703 			return (NULL);
704 		}
705 	}
706 
707 	return (pip);
708 }
709 
710 /*
711  * Allocate and dup parent prison address list.
712  * kern_jail_set() helper.
713  */
714 static void
715 prison_ip_dup(struct prison *ppr, struct prison *pr, const pr_family_t af)
716 {
717 	const struct prison_ip *ppip = ppr->pr_addrs[af];
718 	struct prison_ip *pip;
719 
720 	if (ppip != NULL) {
721 		pip = prison_ip_alloc(af, ppip->ips, M_WAITOK);
722 		bcopy(ppip->pr_ip, pip->pr_ip, pip->ips * pr_families[af].size);
723 		pr->pr_addrs[af] = pip;
724 	}
725 }
726 
727 /*
728  * Make sure the new set of IP addresses is a subset of the parent's list.
729  * Don't worry about the parent being unlocked, as any setting is done with
730  * allprison_lock held.
731  * kern_jail_set() helper.
732  */
733 static bool
734 prison_ip_parent_match(struct prison_ip *ppip, struct prison_ip *pip,
735     const pr_family_t af)
736 {
737 	prison_addr_cmp_t *const cmp = pr_families[af].cmp;
738 	int i, j;
739 
740 	if (ppip == NULL)
741 		return (false);
742 
743 	for (i = 0; i < ppip->ips; i++)
744 		if (cmp(PR_IP(pip, af, 0), PR_IP(ppip, af, i)) == 0)
745 			break;
746 
747 	if (i == ppip->ips)
748 		/* Main address not present in parent. */
749 		return (false);
750 
751 	if (pip->ips > 1) {
752 		for (i = j = 1; i < pip->ips; i++) {
753 			if (cmp(PR_IP(pip, af, i), PR_IP(ppip, af, 0)) == 0)
754 				/* Equals to parent primary address. */
755 				continue;
756 			for (; j < ppip->ips; j++)
757 				if (cmp(PR_IP(pip, af, i),
758 				    PR_IP(ppip, af, j)) == 0)
759 					break;
760 			if (j == ppip->ips)
761 				break;
762 		}
763 		if (j == ppip->ips)
764 			/* Address not present in parent. */
765 			return (false);
766 	}
767 	return (true);
768 }
769 
770 /*
771  * Check for conflicting IP addresses.  We permit them if there is no more
772  * than one IP on each jail.  If there is a duplicate on a jail with more
773  * than one IP stop checking and return error.
774  * kern_jail_set() helper.
775  */
776 static bool
777 prison_ip_conflict_check(const struct prison *ppr, const struct prison *pr,
778     struct prison_ip *pip, pr_family_t af)
779 {
780 	const struct prison *tppr, *tpr;
781 	int descend;
782 
783 #ifdef VIMAGE
784 	for (tppr = ppr; tppr != &prison0; tppr = tppr->pr_parent)
785 		if (tppr->pr_flags & PR_VNET)
786 			break;
787 #else
788 	tppr = &prison0;
789 #endif
790 	FOREACH_PRISON_DESCENDANT(tppr, tpr, descend) {
791 		if (tpr == pr ||
792 #ifdef VIMAGE
793 		    (tpr != tppr && (tpr->pr_flags & PR_VNET)) ||
794 #endif
795 		    !prison_isalive(tpr)) {
796 			descend = 0;
797 			continue;
798 		}
799 		if (!(tpr->pr_flags & pr_families[af].ip_flag))
800 			continue;
801 		descend = 0;
802 		if (tpr->pr_addrs[af] == NULL ||
803 		    (pip->ips == 1 && tpr->pr_addrs[af]->ips == 1))
804 			continue;
805 		for (int i = 0; i < pip->ips; i++)
806 			if (prison_ip_check(tpr, af, PR_IP(pip, af, i)) == 0)
807 				return (false);
808 	}
809 
810 	return (true);
811 }
812 
813 _Static_assert(offsetof(struct prison_ip, ctx) == 0,
814     "prison must start with epoch context");
815 static void
816 prison_ip_free_deferred(epoch_context_t ctx)
817 {
818 
819 	free(ctx, M_PRISON);
820 }
821 
822 static void
823 prison_ip_free(struct prison_ip *pip)
824 {
825 
826 	if (pip != NULL)
827 		NET_EPOCH_CALL(prison_ip_free_deferred, &pip->ctx);
828 }
829 
830 static void
831 prison_ip_set(struct prison *pr, const pr_family_t af, struct prison_ip *new)
832 {
833 	struct prison_ip **mem, *old;
834 
835 	mtx_assert(&pr->pr_mtx, MA_OWNED);
836 
837 	mem = &pr->pr_addrs[af];
838 
839 	old = *mem;
840 	atomic_store_ptr(mem, new);
841 	prison_ip_free(old);
842 }
843 
844 /*
845  * Restrict a prison's IP address list with its parent's, possibly replacing
846  * it.  Return true if succeed, otherwise should redo.
847  * kern_jail_set() helper.
848  */
849 static bool
850 prison_ip_restrict(struct prison *pr, const pr_family_t af,
851     struct prison_ip **newp)
852 {
853 	struct prison_ip *ppip = pr->pr_parent->pr_addrs[af];
854 	struct prison_ip *pip = pr->pr_addrs[af];
855 	int (*const cmp)(const void *, const void *) = pr_families[af].cmp;
856 	const size_t size = pr_families[af].size;
857 	struct prison_ip *new = newp != NULL ? *newp : NULL;
858 	uint32_t ips;
859 
860 	mtx_assert(&pr->pr_mtx, MA_OWNED);
861 
862 	/*
863 	 * Due to epoch-synchronized access to the IP address lists we always
864 	 * allocate a new list even if the old one has enough space.  We could
865 	 * atomically update an IPv4 address inside a list, but that would
866 	 * screw up sorting, and in case of IPv6 we can't even atomically write
867 	 * one.
868 	 */
869 	if (ppip == NULL) {
870 		if (pip != NULL)
871 			prison_ip_set(pr, af, NULL);
872 		return (true);
873 	}
874 
875 	if (!(pr->pr_flags & pr_families[af].ip_flag)) {
876 		if (new == NULL) {
877 			new = prison_ip_alloc(af, ppip->ips, M_NOWAIT);
878 			if (new == NULL)
879 				return (false); /* Redo */
880 		}
881 		/* This has no user settings, so just copy the parent's list. */
882 		MPASS(new->ips == ppip->ips);
883 		bcopy(ppip->pr_ip, new->pr_ip, ppip->ips * size);
884 		prison_ip_set(pr, af, new);
885 		if (newp != NULL)
886 			*newp = NULL; /* Used */
887 	} else if (pip != NULL) {
888 		/* Remove addresses that aren't in the parent. */
889 		int i;
890 
891 		i = 0; /* index in pip */
892 		ips = 0; /* index in new */
893 
894 		if (new == NULL) {
895 			new = prison_ip_alloc(af, pip->ips, M_NOWAIT);
896 			if (new == NULL)
897 				return (false); /* Redo */
898 		}
899 
900 		for (int pi = 0; pi < ppip->ips; pi++)
901 			if (cmp(PR_IP(pip, af, 0), PR_IP(ppip, af, pi)) == 0) {
902 				/* Found our primary address in parent. */
903 				bcopy(PR_IP(pip, af, i), PR_IP(new, af, ips),
904 				    size);
905 				i++;
906 				ips++;
907 				break;
908 			}
909 		for (int pi = 1; i < pip->ips; ) {
910 			/* Check against primary, which is unsorted. */
911 			if (cmp(PR_IP(pip, af, i), PR_IP(ppip, af, 0)) == 0) {
912 				/* Matches parent's primary address. */
913 				bcopy(PR_IP(pip, af, i), PR_IP(new, af, ips),
914 				    size);
915 				i++;
916 				ips++;
917 				continue;
918 			}
919 			/* The rest are sorted. */
920 			switch (pi >= ppip->ips ? -1 :
921 				cmp(PR_IP(pip, af, i), PR_IP(ppip, af, pi))) {
922 			case -1:
923 				i++;
924 				break;
925 			case 0:
926 				bcopy(PR_IP(pip, af, i), PR_IP(new, af, ips),
927 				    size);
928 				i++;
929 				pi++;
930 				ips++;
931 				break;
932 			case 1:
933 				pi++;
934 				break;
935 			}
936 		}
937 		if (ips == 0) {
938 			if (newp == NULL || *newp == NULL)
939 				prison_ip_free(new);
940 			new = NULL;
941 		} else {
942 			/* Shrink to real size */
943 			KASSERT((new->ips >= ips),
944 			    ("Out-of-bounds write to prison_ip %p", new));
945 			new->ips = ips;
946 		}
947 		prison_ip_set(pr, af, new);
948 		if (newp != NULL)
949 			*newp = NULL; /* Used */
950 	}
951 	return (true);
952 }
953 
954 /*
955  * Fast-path check if an address belongs to a prison.
956  */
957 int
958 prison_ip_check(const struct prison *pr, const pr_family_t af,
959     const void *addr)
960 {
961 	int (*const cmp)(const void *, const void *) = pr_families[af].cmp;
962 	struct prison_ip *pip;
963 	int i, a, z, d;
964 
965 	MPASS(mtx_owned(&pr->pr_mtx) ||
966 	    in_epoch(net_epoch_preempt) ||
967 	    sx_xlocked(&allprison_lock));
968 
969 	pip = atomic_load_ptr(&pr->pr_addrs[af]);
970 	if (__predict_false(pip == NULL))
971 		return (EAFNOSUPPORT);
972 
973 	/* Check the primary IP. */
974 	if (cmp(PR_IP(pip, af, 0), addr) == 0)
975 		return (0);
976 
977 	/*
978 	 * All the other IPs are sorted so we can do a binary search.
979 	 */
980 	a = 0;
981 	z = pip->ips - 2;
982 	while (a <= z) {
983 		i = (a + z) / 2;
984 		d = cmp(PR_IP(pip, af, i + 1), addr);
985 		if (d > 0)
986 			z = i - 1;
987 		else if (d < 0)
988 			a = i + 1;
989 		else
990 			return (0);
991 	}
992 
993 	return (EADDRNOTAVAIL);
994 }
995 
996 /*
997  * Grab primary IP.  Historically required mutex, but nothing prevents
998  * us to support epoch-protected access.  Is it used in fast path?
999  * in{6}_jail.c helper
1000  */
1001 const void *
1002 prison_ip_get0(const struct prison *pr, const pr_family_t af)
1003 {
1004 	const struct prison_ip *pip = pr->pr_addrs[af];
1005 
1006 	mtx_assert(&pr->pr_mtx, MA_OWNED);
1007 	MPASS(pip);
1008 
1009 	return (pip->pr_ip);
1010 }
1011 
1012 u_int
1013 prison_ip_cnt(const struct prison *pr, const pr_family_t af)
1014 {
1015 
1016 	return (pr->pr_addrs[af]->ips);
1017 }
1018 #endif	/* defined(INET) || defined(INET6) */
1019 
1020 int
1021 kern_jail_set(struct thread *td, struct uio *optuio, int flags)
1022 {
1023 	struct file *jfp_out;
1024 	struct nameidata nd;
1025 #ifdef INET
1026 	struct prison_ip *ip4;
1027 #endif
1028 #ifdef INET6
1029 	struct prison_ip *ip6;
1030 #endif
1031 	struct vfsopt *opt;
1032 	struct vfsoptlist *opts;
1033 	struct prison *pr, *deadpr, *dinspr, *inspr, *mypr, *ppr, *tpr;
1034 	struct ucred *jdcred;
1035 	struct vnode *root;
1036 	char *domain, *errmsg, *host, *name, *namelc, *p, *path, *uuid;
1037 	char *g_path, *osrelstr;
1038 	struct bool_flags *bf;
1039 	struct jailsys_flags *jsf;
1040 #if defined(INET) || defined(INET6)
1041 	void *op;
1042 #endif
1043 	unsigned long hid;
1044 	size_t namelen, onamelen, pnamelen;
1045 #ifdef MAC
1046 	void *mac_set_prison_data = NULL;
1047 	int gotmaclabel;
1048 #endif
1049 	int created, cuflags, descend, drflags, enforce;
1050 	int error, errmsg_len, errmsg_pos;
1051 	int gotchildmax, gotenforce, gothid, gotrsnum, gotslevel;
1052 	int deadid, jfd_in, jfd_out, jfd_pos, jid, jsys, len, level;
1053 	int childmax, osreldt, rsnum, slevel;
1054 #ifdef INET
1055 	int ip4s;
1056 	bool redo_ip4;
1057 #endif
1058 #ifdef INET6
1059 	int ip6s;
1060 	bool redo_ip6;
1061 #endif
1062 	bool maybe_changed;
1063 	uint64_t pr_allow, ch_allow, pr_flags, ch_flags;
1064 	uint64_t pr_allow_diff;
1065 	unsigned tallow;
1066 	char numbuf[12];
1067 
1068 	mypr = td->td_ucred->cr_prison;
1069 	if (((flags & (JAIL_CREATE | JAIL_AT_DESC)) == JAIL_CREATE) &&
1070 	    mypr->pr_childmax == 0)
1071 		return (EPERM);
1072 	if (flags & ~JAIL_SET_MASK)
1073 		return (EINVAL);
1074 	if ((flags & (JAIL_USE_DESC | JAIL_AT_DESC)) ==
1075 	    (JAIL_USE_DESC | JAIL_AT_DESC))
1076 		return (EINVAL);
1077 
1078 	/* Only let a single thread in the process try to attach at a time. */
1079 	if (flags & JAIL_ATTACH) {
1080 		error = prison_attach_thread_single(td);
1081 		if (error != 0)
1082 			return (error);
1083 	}
1084 
1085 #ifdef INET
1086 	ip4 = NULL;
1087 #endif
1088 #ifdef INET6
1089 	ip6 = NULL;
1090 #endif
1091 	g_path = NULL;
1092 	jfp_out = NULL;
1093 	jfd_out = -1;
1094 	prison_hold(mypr);
1095 	/*
1096 	 * Check all the parameters before committing to anything.  Not all
1097 	 * errors can be caught early, but we may as well try.  Also, this
1098 	 * takes care of some expensive stuff (path lookup) before getting
1099 	 * the allprison lock.
1100 	 *
1101 	 * XXX Jails are not filesystems, and jail parameters are not mount
1102 	 *     options.  But it makes more sense to re-use the vfsopt code
1103 	 *     than duplicate it under a different name.
1104 	 */
1105 	error = vfs_buildopts(optuio, &opts);
1106 	if (error) {
1107 		opts = NULL;
1108 		goto done_free;
1109 	}
1110 
1111 	cuflags = flags & (JAIL_CREATE | JAIL_UPDATE);
1112 	if (!cuflags) {
1113 		error = EINVAL;
1114 		vfs_opterror(opts, "no valid operation (create or update)");
1115 		goto done_errmsg;
1116 	}
1117 
1118 	error = vfs_copyopt(opts, JAIL_PARAM_DESC, &jfd_in, sizeof(jfd_in));
1119 	if (error == ENOENT) {
1120 		if (flags & (JAIL_USE_DESC | JAIL_AT_DESC | JAIL_GET_DESC |
1121 		    JAIL_OWN_DESC)) {
1122 			vfs_opterror(opts, "missing desc");
1123 			goto done_errmsg;
1124 		}
1125 		jfd_in = -1;
1126 	} else if (error != 0)
1127 		goto done_free;
1128 	else {
1129 		if (!(flags & (JAIL_USE_DESC | JAIL_AT_DESC | JAIL_GET_DESC |
1130 		    JAIL_OWN_DESC))) {
1131 			error = EINVAL;
1132 			vfs_opterror(opts, "unexpected desc");
1133 			goto done_errmsg;
1134 		}
1135 		if (flags & JAIL_AT_DESC) {
1136 			/*
1137 			 * Look up and create jails based on the
1138 			 * descriptor's prison.
1139 			 */
1140 			struct prison *jdpr;
1141 
1142 			error = jaildesc_find(td, jfd_in, &jdpr, NULL);
1143 			if (error != 0) {
1144 				vfs_opterror(opts, error == ENOENT ?
1145 				    "descriptor to dead jail" :
1146 				    "not a jail descriptor");
1147 				goto done_errmsg;
1148 			}
1149 			prison_free(mypr);
1150 			mypr = jdpr;
1151 			if ((flags & JAIL_CREATE) && mypr->pr_childmax == 0) {
1152 				error = EPERM;
1153 				goto done_free;
1154 			}
1155 		}
1156 		if (flags & (JAIL_GET_DESC | JAIL_OWN_DESC)) {
1157 			/* Allocate a jail descriptor to return later. */
1158 			error = jaildesc_alloc(td, &jfp_out, &jfd_out,
1159 				flags & JAIL_OWN_DESC);
1160 			if (error)
1161 				goto done_free;
1162 		}
1163 	}
1164 
1165 	/*
1166 	 * Delay the permission check if using a jail descriptor,
1167 	 * until we get the descriptor's credentials.
1168 	 */
1169 	if (!(flags & JAIL_USE_DESC)) {
1170 		error = priv_check(td, PRIV_JAIL_SET);
1171 		if (error == 0 && (flags & JAIL_ATTACH))
1172 			error = priv_check(td, PRIV_JAIL_ATTACH);
1173 		if (error)
1174 			goto done_free;
1175 	}
1176 
1177 	error = vfs_copyopt(opts, JAIL_PARAM_JID, &jid, sizeof(jid));
1178 	if (error == ENOENT)
1179 		jid = 0;
1180 	else if (error != 0)
1181 		goto done_free;
1182 
1183 	error = vfs_copyopt(opts, JAIL_PARAM_SECURELEVEL, &slevel, sizeof(slevel));
1184 	if (error == ENOENT)
1185 		gotslevel = 0;
1186 	else if (error != 0)
1187 		goto done_free;
1188 	else
1189 		gotslevel = 1;
1190 
1191 	error =
1192 	    vfs_copyopt(opts, JAIL_PARAM_CHILDREN_MAX, &childmax, sizeof(childmax));
1193 	if (error == ENOENT)
1194 		gotchildmax = 0;
1195 	else if (error != 0)
1196 		goto done_free;
1197 	else
1198 		gotchildmax = 1;
1199 
1200 	error = vfs_copyopt(opts, JAIL_PARAM_ENFORCE_STATFS, &enforce,
1201 	    sizeof(enforce));
1202 	if (error == ENOENT)
1203 		gotenforce = 0;
1204 	else if (error != 0)
1205 		goto done_free;
1206 	else if (enforce < 0 || enforce > 2) {
1207 		error = EINVAL;
1208 		goto done_free;
1209 	} else
1210 		gotenforce = 1;
1211 
1212 	error = vfs_copyopt(opts, JAIL_PARAM_DEVFS_RULESET, &rsnum, sizeof(rsnum));
1213 	if (error == ENOENT)
1214 		gotrsnum = 0;
1215 	else if (error != 0)
1216 		goto done_free;
1217 	else
1218 		gotrsnum = 1;
1219 
1220 	pr_flags = ch_flags = 0;
1221 	for (bf = pr_flag_bool;
1222 	     bf < pr_flag_bool + nitems(pr_flag_bool);
1223 	     bf++) {
1224 		vfs_flagopt(opts, bf->name, &pr_flags, bf->flag);
1225 		vfs_flagopt(opts, bf->noname, &ch_flags, bf->flag);
1226 	}
1227 	ch_flags |= pr_flags;
1228 	for (jsf = pr_flag_jailsys;
1229 	     jsf < pr_flag_jailsys + nitems(pr_flag_jailsys);
1230 	     jsf++) {
1231 		error = vfs_copyopt(opts, jsf->name, &jsys, sizeof(jsys));
1232 		if (error == ENOENT)
1233 			continue;
1234 		if (error != 0)
1235 			goto done_free;
1236 		switch (jsys) {
1237 		case JAIL_SYS_DISABLE:
1238 			if (!jsf->disable) {
1239 				error = EINVAL;
1240 				goto done_free;
1241 			}
1242 			pr_flags |= jsf->disable;
1243 			break;
1244 		case JAIL_SYS_NEW:
1245 			pr_flags |= jsf->new;
1246 			break;
1247 		case JAIL_SYS_INHERIT:
1248 			break;
1249 		default:
1250 			error = EINVAL;
1251 			goto done_free;
1252 		}
1253 		ch_flags |= jsf->new | jsf->disable;
1254 	}
1255 	if ((flags & (JAIL_CREATE | JAIL_ATTACH)) == JAIL_CREATE
1256 	    && !(pr_flags & PR_PERSIST)) {
1257 		error = EINVAL;
1258 		vfs_opterror(opts, "new jail must persist or attach");
1259 		goto done_errmsg;
1260 	}
1261 #ifdef VIMAGE
1262 	if ((flags & JAIL_UPDATE) && (ch_flags & PR_VNET)) {
1263 		error = EINVAL;
1264 		vfs_opterror(opts, "vnet cannot be changed after creation");
1265 		goto done_errmsg;
1266 	}
1267 #endif
1268 #ifdef INET
1269 	if ((flags & JAIL_UPDATE) && (ch_flags & PR_IP4_USER)) {
1270 		error = EINVAL;
1271 		vfs_opterror(opts, "ip4 cannot be changed after creation");
1272 		goto done_errmsg;
1273 	}
1274 #endif
1275 #ifdef INET6
1276 	if ((flags & JAIL_UPDATE) && (ch_flags & PR_IP6_USER)) {
1277 		error = EINVAL;
1278 		vfs_opterror(opts, "ip6 cannot be changed after creation");
1279 		goto done_errmsg;
1280 	}
1281 #endif
1282 
1283 	pr_allow = ch_allow = 0;
1284 	for (bf = pr_flag_allow;
1285 	     bf < pr_flag_allow + nitems(pr_flag_allow) &&
1286 		atomic_load_int(&bf->flag) != 0;
1287 	     bf++) {
1288 		vfs_flagopt(opts, bf->name, &pr_allow, bf->flag);
1289 		vfs_flagopt(opts, bf->noname, &ch_allow, bf->flag);
1290 	}
1291 	ch_allow |= pr_allow;
1292 
1293 	error = vfs_getopt(opts, JAIL_PARAM_NAME, (void **)&name, &len);
1294 	if (error == ENOENT)
1295 		name = NULL;
1296 	else if (error != 0)
1297 		goto done_free;
1298 	else {
1299 		if (len == 0 || name[len - 1] != '\0') {
1300 			error = EINVAL;
1301 			goto done_free;
1302 		}
1303 		if (len > MAXHOSTNAMELEN) {
1304 			error = ENAMETOOLONG;
1305 			goto done_free;
1306 		}
1307 	}
1308 
1309 	error = vfs_getopt(opts, JAIL_PARAM_HOST_HOSTNAME, (void **)&host, &len);
1310 	if (error == ENOENT)
1311 		host = NULL;
1312 	else if (error != 0)
1313 		goto done_free;
1314 	else {
1315 		ch_flags |= PR_HOST;
1316 		pr_flags |= PR_HOST;
1317 		if (len == 0 || host[len - 1] != '\0') {
1318 			error = EINVAL;
1319 			goto done_free;
1320 		}
1321 		if (len > MAXHOSTNAMELEN) {
1322 			error = ENAMETOOLONG;
1323 			goto done_free;
1324 		}
1325 	}
1326 
1327 	error = vfs_getopt(opts, JAIL_PARAM_HOST_DOMAINNAME, (void **)&domain, &len);
1328 	if (error == ENOENT)
1329 		domain = NULL;
1330 	else if (error != 0)
1331 		goto done_free;
1332 	else {
1333 		ch_flags |= PR_HOST;
1334 		pr_flags |= PR_HOST;
1335 		if (len == 0 || domain[len - 1] != '\0') {
1336 			error = EINVAL;
1337 			goto done_free;
1338 		}
1339 		if (len > MAXHOSTNAMELEN) {
1340 			error = ENAMETOOLONG;
1341 			goto done_free;
1342 		}
1343 	}
1344 
1345 	error = vfs_getopt(opts, JAIL_PARAM_HOST_HOSTUUID, (void **)&uuid, &len);
1346 	if (error == ENOENT)
1347 		uuid = NULL;
1348 	else if (error != 0)
1349 		goto done_free;
1350 	else {
1351 		ch_flags |= PR_HOST;
1352 		pr_flags |= PR_HOST;
1353 		if (len == 0 || uuid[len - 1] != '\0') {
1354 			error = EINVAL;
1355 			goto done_free;
1356 		}
1357 		if (len > HOSTUUIDLEN) {
1358 			error = ENAMETOOLONG;
1359 			goto done_free;
1360 		}
1361 	}
1362 
1363 #ifdef COMPAT_FREEBSD32
1364 	if (SV_PROC_FLAG(td->td_proc, SV_ILP32)) {
1365 		uint32_t hid32;
1366 
1367 		error = vfs_copyopt(opts, JAIL_PARAM_HOST_HOSTID, &hid32, sizeof(hid32));
1368 		hid = hid32;
1369 	} else
1370 #endif
1371 		error = vfs_copyopt(opts, JAIL_PARAM_HOST_HOSTID, &hid, sizeof(hid));
1372 	if (error == ENOENT)
1373 		gothid = 0;
1374 	else if (error != 0)
1375 		goto done_free;
1376 	else {
1377 		gothid = 1;
1378 		ch_flags |= PR_HOST;
1379 		pr_flags |= PR_HOST;
1380 	}
1381 
1382 #ifdef MAC
1383 	/* Process the mac.label vfsopt */
1384 	error = mac_set_prison_prepare(td, opts, &mac_set_prison_data);
1385 	if (error == ENOENT)
1386 		gotmaclabel = 0;
1387 	else if (error != 0)
1388 		goto done_errmsg;
1389 	else
1390 		gotmaclabel = 1;
1391 #endif
1392 
1393 #ifdef INET
1394 	error = vfs_getopt(opts, JAIL_PARAM_IP4_ADDR, &op, &ip4s);
1395 	if (error == ENOENT)
1396 		ip4s = 0;
1397 	else if (error != 0)
1398 		goto done_free;
1399 	else if (ip4s & (sizeof(struct in_addr) - 1)) {
1400 		error = EINVAL;
1401 		goto done_free;
1402 	} else {
1403 		ch_flags |= PR_IP4_USER;
1404 		pr_flags |= PR_IP4_USER;
1405 		if (ip4s > 0) {
1406 			ip4s /= sizeof(struct in_addr);
1407 			if (ip4s > jail_max_af_ips) {
1408 				error = EINVAL;
1409 				vfs_opterror(opts, "too many IPv4 addresses");
1410 				goto done_errmsg;
1411 			}
1412 			ip4 = prison_ip_copyin(PR_INET, op, ip4s);
1413 			if (ip4 == NULL) {
1414 				error = EINVAL;
1415 				goto done_free;
1416 			}
1417 		}
1418 	}
1419 #endif
1420 
1421 #ifdef INET6
1422 	error = vfs_getopt(opts, JAIL_PARAM_IP6_ADDR, &op, &ip6s);
1423 	if (error == ENOENT)
1424 		ip6s = 0;
1425 	else if (error != 0)
1426 		goto done_free;
1427 	else if (ip6s & (sizeof(struct in6_addr) - 1)) {
1428 		error = EINVAL;
1429 		goto done_free;
1430 	} else {
1431 		ch_flags |= PR_IP6_USER;
1432 		pr_flags |= PR_IP6_USER;
1433 		if (ip6s > 0) {
1434 			ip6s /= sizeof(struct in6_addr);
1435 			if (ip6s > jail_max_af_ips) {
1436 				error = EINVAL;
1437 				vfs_opterror(opts, "too many IPv6 addresses");
1438 				goto done_errmsg;
1439 			}
1440 			ip6 = prison_ip_copyin(PR_INET6, op, ip6s);
1441 			if (ip6 == NULL) {
1442 				error = EINVAL;
1443 				goto done_free;
1444 			}
1445 		}
1446 	}
1447 #endif
1448 
1449 #if defined(VIMAGE) && (defined(INET) || defined(INET6))
1450 	if ((ch_flags & PR_VNET) && (ch_flags & (PR_IP4_USER | PR_IP6_USER))) {
1451 		error = EINVAL;
1452 		vfs_opterror(opts,
1453 		    "vnet jails cannot have IP address restrictions");
1454 		goto done_errmsg;
1455 	}
1456 #endif
1457 
1458 	error = vfs_getopt(opts, JAIL_PARAM_OSRELEASE, (void **)&osrelstr, &len);
1459 	if (error == ENOENT)
1460 		osrelstr = NULL;
1461 	else if (error != 0)
1462 		goto done_free;
1463 	else {
1464 		if (flags & JAIL_UPDATE) {
1465 			error = EINVAL;
1466 			vfs_opterror(opts,
1467 			    "osrelease cannot be changed after creation");
1468 			goto done_errmsg;
1469 		}
1470 		if (len == 0 || osrelstr[len - 1] != '\0') {
1471 			error = EINVAL;
1472 			goto done_free;
1473 		}
1474 		if (len >= OSRELEASELEN) {
1475 			error = ENAMETOOLONG;
1476 			vfs_opterror(opts,
1477 			    "osrelease string must be 1-%d bytes long",
1478 			    OSRELEASELEN - 1);
1479 			goto done_errmsg;
1480 		}
1481 	}
1482 
1483 	error = vfs_copyopt(opts, JAIL_PARAM_OSRELDATE, &osreldt, sizeof(osreldt));
1484 	if (error == ENOENT)
1485 		osreldt = 0;
1486 	else if (error != 0)
1487 		goto done_free;
1488 	else {
1489 		if (flags & JAIL_UPDATE) {
1490 			error = EINVAL;
1491 			vfs_opterror(opts,
1492 			    "osreldate cannot be changed after creation");
1493 			goto done_errmsg;
1494 		}
1495 		if (osreldt == 0) {
1496 			error = EINVAL;
1497 			vfs_opterror(opts, "osreldate cannot be 0");
1498 			goto done_errmsg;
1499 		}
1500 	}
1501 
1502 	root = NULL;
1503 	error = vfs_getopt(opts, JAIL_PARAM_PATH, (void **)&path, &len);
1504 	if (error == ENOENT)
1505 		path = NULL;
1506 	else if (error != 0)
1507 		goto done_free;
1508 	else {
1509 		if (flags & JAIL_UPDATE) {
1510 			error = EINVAL;
1511 			vfs_opterror(opts,
1512 			    "path cannot be changed after creation");
1513 			goto done_errmsg;
1514 		}
1515 		if (len == 0 || path[len - 1] != '\0') {
1516 			error = EINVAL;
1517 			goto done_free;
1518 		}
1519 		NDINIT(&nd, LOOKUP, FOLLOW | LOCKLEAF, UIO_SYSSPACE, path);
1520 		error = namei(&nd);
1521 		if (error)
1522 			goto done_free;
1523 		root = nd.ni_vp;
1524 		NDFREE_PNBUF(&nd);
1525 		g_path = malloc(MAXPATHLEN, M_TEMP, M_WAITOK);
1526 		strlcpy(g_path, path, MAXPATHLEN);
1527 		error = vn_path_to_global_path(td, root, g_path, MAXPATHLEN);
1528 		if (error == 0) {
1529 			path = g_path;
1530 		} else {
1531 			/* exit on other errors */
1532 			goto done_free;
1533 		}
1534 		if (root->v_type != VDIR) {
1535 			error = ENOTDIR;
1536 			vput(root);
1537 			goto done_free;
1538 		}
1539 		VOP_UNLOCK(root);
1540 	}
1541 
1542 	/*
1543 	 * Find the specified jail, or at least its parent.
1544 	 * This abuses the file error codes ENOENT and EEXIST.
1545 	 */
1546 	pr = NULL;
1547 	inspr = NULL;
1548 	deadpr = NULL;
1549 	maybe_changed = false;
1550 	if (cuflags == JAIL_CREATE && jid == 0 && name != NULL) {
1551 		namelc = strrchr(name, '.');
1552 		jid = strtoul(namelc != NULL ? namelc + 1 : name, &p, 10);
1553 		if (*p != '\0')
1554 			jid = 0;
1555 	}
1556 	sx_xlock(&allprison_lock);
1557 	drflags = PD_LIST_XLOCKED;
1558 	ppr = mypr;
1559 	if (!prison_isalive(ppr)) {
1560 		/* This jail is dying.  This process will surely follow. */
1561 		error = EAGAIN;
1562 		goto done_deref;
1563 	}
1564 	if (flags & JAIL_USE_DESC) {
1565 		/* Get the jail from its descriptor. */
1566 		error = jaildesc_find(td, jfd_in, &pr, &jdcred);
1567 		if (error) {
1568 			vfs_opterror(opts, error == ENOENT ?
1569 			    "descriptor to dead jail" :
1570 			    "not a jail descriptor");
1571 			goto done_deref;
1572 		}
1573 		drflags |= PD_DEREF;
1574 		error = priv_check_cred(jdcred, PRIV_JAIL_SET);
1575 		if (error == 0 && (flags & JAIL_ATTACH))
1576 			error = priv_check_cred(jdcred, PRIV_JAIL_ATTACH);
1577 		crfree(jdcred);
1578 		if (error)
1579 			goto done_deref;
1580 		mtx_lock(&pr->pr_mtx);
1581 		drflags |= PD_LOCKED;
1582 		if (cuflags == JAIL_CREATE) {
1583 			error = EEXIST;
1584 			vfs_opterror(opts, "jail %d already exists",
1585 			    pr->pr_id);
1586 			goto done_deref;
1587 		}
1588 		if (!prison_isalive(pr)) {
1589 			/* While a jid can be resurrected, the prison
1590 			 * itself cannot.
1591 			 */
1592 			error = ENOENT;
1593 			vfs_opterror(opts, "jail %d is dying", pr->pr_id);
1594 			goto done_deref;
1595 		}
1596 		if (jid != 0 && jid != pr->pr_id) {
1597 			error = EINVAL;
1598 			vfs_opterror(opts, "cannot change jid");
1599 			goto done_deref;
1600 		}
1601 		jid = pr->pr_id;
1602 	} else if (jid != 0) {
1603 		if (jid < 0) {
1604 			error = EINVAL;
1605 			vfs_opterror(opts, "negative jid");
1606 			goto done_deref;
1607 		}
1608 		/*
1609 		 * See if a requested jid already exists.  Keep track of
1610 		 * where it can be inserted later.
1611 		 */
1612 		TAILQ_FOREACH(inspr, &allprison, pr_list) {
1613 			if (inspr->pr_id < jid)
1614 				continue;
1615 			if (inspr->pr_id > jid)
1616 				break;
1617 			if (prison_isalive(inspr)) {
1618 				pr = inspr;
1619 				mtx_lock(&pr->pr_mtx);
1620 				drflags |= PD_LOCKED;
1621 			} else {
1622 				/* Note a dying jail to handle later. */
1623 				deadpr = inspr;
1624 			}
1625 			inspr = NULL;
1626 			break;
1627 		}
1628 		if (cuflags == JAIL_CREATE && pr != NULL) {
1629 			/*
1630 			 * Even creators that cannot see the jail will
1631 			 * get EEXIST.
1632 			 */
1633 			error = EEXIST;
1634 			vfs_opterror(opts, "jail %d already exists", jid);
1635 			goto done_deref;
1636 		}
1637 		if ((pr == NULL)
1638 		    ? cuflags == JAIL_UPDATE
1639 		    : !prison_ischild(mypr, pr)) {
1640 			/*
1641 			 * Updaters get ENOENT for nonexistent jails,
1642 			 * or for jails they cannot see.  The latter
1643 			 * case is true even for CREATE | UPDATE,
1644 			 * which normally cannot give this error.
1645 			 */
1646 			error = ENOENT;
1647 			vfs_opterror(opts, "jail %d not found", jid);
1648 			goto done_deref;
1649 		}
1650 	}
1651 	/*
1652 	 * If the caller provided a name, look for a jail by that name.
1653 	 * This has different semantics for creates and updates keyed by jid
1654 	 * (where the name must not already exist in a different jail),
1655 	 * and updates keyed by the name itself (where the name must exist
1656 	 * because that is the jail being updated).
1657 	 */
1658 	namelc = NULL;
1659 	if (name != NULL) {
1660 		namelc = strrchr(name, '.');
1661 		if (namelc == NULL)
1662 			namelc = name;
1663 		else {
1664 			/*
1665 			 * This is a hierarchical name.  Split it into the
1666 			 * parent and child names, and make sure the parent
1667 			 * exists or matches an already found jail.
1668 			 */
1669 			if (pr != NULL) {
1670 				if (strncmp(name, ppr->pr_name, namelc - name)
1671 				    || ppr->pr_name[namelc - name] != '\0') {
1672 					error = EINVAL;
1673 					vfs_opterror(opts,
1674 					    "cannot change jail's parent");
1675 					goto done_deref;
1676 				}
1677 			} else {
1678 				*namelc = '\0';
1679 				ppr = prison_find_name(mypr, name);
1680 				if (ppr == NULL) {
1681 					error = ENOENT;
1682 					vfs_opterror(opts,
1683 					    "jail \"%s\" not found", name);
1684 					goto done_deref;
1685 				}
1686 				mtx_unlock(&ppr->pr_mtx);
1687 				if (!prison_isalive(ppr)) {
1688 					error = ENOENT;
1689 					vfs_opterror(opts,
1690 					    "jail \"%s\" is dying", name);
1691 					goto done_deref;
1692 				}
1693 				*namelc = '.';
1694 			}
1695 			namelc++;
1696 		}
1697 		if (namelc[0] != '\0') {
1698 			pnamelen =
1699 			    (ppr == &prison0) ? 0 : strlen(ppr->pr_name) + 1;
1700 			FOREACH_PRISON_CHILD(ppr, tpr) {
1701 				if (tpr == pr || !prison_isalive(tpr) ||
1702 				    strcmp(tpr->pr_name + pnamelen, namelc))
1703 					continue;
1704 				if (cuflags == JAIL_CREATE || pr != NULL) {
1705 					/*
1706 					 * Create, or update(jid): name must
1707 					 * not exist in an active sibling jail.
1708 					 */
1709 					error = EEXIST;
1710 					vfs_opterror(opts,
1711 					    "jail \"%s\" already exists", name);
1712 					goto done_deref;
1713 				}
1714 				/* Use this jail for updates. */
1715 				pr = tpr;
1716 				mtx_lock(&pr->pr_mtx);
1717 				drflags |= PD_LOCKED;
1718 				break;
1719 			}
1720 			/*
1721 			 * Update: name must exist if no jid is specified.
1722 			 * As with the jid case, the jail must be currently
1723 			 * visible, or else even CREATE | UPDATE will get
1724 			 * an error.
1725 			 */
1726 			if ((pr == NULL)
1727 			    ? cuflags == JAIL_UPDATE
1728 			    : !prison_isalive(pr)) {
1729 				error = ENOENT;
1730 				vfs_opterror(opts, "jail \"%s\" not found",
1731 				    name);
1732 				goto done_deref;
1733 			}
1734 		}
1735 	}
1736 	/* Update: must provide a desc, jid, or name. */
1737 	else if (cuflags == JAIL_UPDATE && pr == NULL) {
1738 		error = ENOENT;
1739 		vfs_opterror(opts, "update specified no jail");
1740 		goto done_deref;
1741 	}
1742 
1743 	/* If there's no prison to update, create a new one and link it in. */
1744 	created = pr == NULL;
1745 	if (created) {
1746 #ifdef MAC
1747 		error = mac_prison_check_create(td->td_ucred, opts, flags);
1748 		if (error != 0)
1749 			goto done_deref;
1750 #endif
1751 		for (tpr = mypr; tpr != NULL; tpr = tpr->pr_parent)
1752 			if (tpr->pr_childcount >= tpr->pr_childmax) {
1753 				error = EPERM;
1754 				vfs_opterror(opts, "prison limit exceeded");
1755 				goto done_deref;
1756 			}
1757 
1758 		if (deadpr != NULL) {
1759 			/*
1760 			 * The prison being created has the same ID as a dying
1761 			 * one.  Handle this by giving the dying jail a new ID.
1762 			 * This may cause some confusion to user space, but
1763 			 * only to those listing dying jails.
1764 			 */
1765 			deadid = get_next_deadid(&dinspr);
1766 			if (deadid == 0) {
1767 				error = EAGAIN;
1768 				vfs_opterror(opts, "no available jail IDs");
1769 				goto done_deref;
1770 			}
1771 			mtx_lock(&deadpr->pr_mtx);
1772 			deadpr->pr_id = deadid;
1773 			mtx_unlock(&deadpr->pr_mtx);
1774 			if (dinspr == deadpr)
1775 				inspr = deadpr;
1776 			else {
1777 				inspr = TAILQ_NEXT(deadpr, pr_list);
1778 				TAILQ_REMOVE(&allprison, deadpr, pr_list);
1779 				if (dinspr != NULL)
1780 					TAILQ_INSERT_AFTER(&allprison, dinspr,
1781 					    deadpr, pr_list);
1782 				else
1783 					TAILQ_INSERT_HEAD(&allprison, deadpr,
1784 					    pr_list);
1785 			}
1786 		}
1787 		if (jid == 0 && (jid = get_next_prid(&inspr)) == 0) {
1788 			error = EAGAIN;
1789 			vfs_opterror(opts, "no available jail IDs");
1790 			goto done_deref;
1791 		}
1792 
1793 		pr = malloc(sizeof(*pr), M_PRISON, M_WAITOK | M_ZERO);
1794 		pr->pr_state = PRISON_STATE_INVALID;
1795 		refcount_init(&pr->pr_ref, 1);
1796 		refcount_init(&pr->pr_uref, 0);
1797 		drflags |= PD_DEREF;
1798 		LIST_INIT(&pr->pr_children);
1799 		mtx_init(&pr->pr_mtx, "jail mutex", NULL, MTX_DEF | MTX_DUPOK);
1800 		TASK_INIT(&pr->pr_task, 0, prison_complete, pr);
1801 
1802 		pr->pr_id = jid;
1803 		if (inspr != NULL)
1804 			TAILQ_INSERT_BEFORE(inspr, pr, pr_list);
1805 		else
1806 			TAILQ_INSERT_TAIL(&allprison, pr, pr_list);
1807 
1808 		pr->pr_parent = ppr;
1809 		prison_hold(ppr);
1810 		prison_proc_hold(ppr);
1811 		LIST_INSERT_HEAD(&ppr->pr_children, pr, pr_sibling);
1812 		for (tpr = ppr; tpr != NULL; tpr = tpr->pr_parent)
1813 			tpr->pr_childcount++;
1814 		pr->pr_klist = knlist_alloc(&pr->pr_mtx);
1815 
1816 		/* Set some default values, and inherit some from the parent. */
1817 		if (namelc == NULL)
1818 			namelc = "";
1819 		if (path == NULL) {
1820 			path = "/";
1821 			root = ppr->pr_root;
1822 			vref(root);
1823 		}
1824 		strlcpy(pr->pr_hostuuid, DEFAULT_HOSTUUID, HOSTUUIDLEN);
1825 		pr->pr_flags |= PR_HOST;
1826 #if defined(INET) || defined(INET6)
1827 #ifdef VIMAGE
1828 		if (!(pr_flags & PR_VNET))
1829 #endif
1830 		{
1831 #ifdef INET
1832 			if (!(ch_flags & PR_IP4_USER))
1833 				pr->pr_flags |= PR_IP4 | PR_IP4_USER;
1834 			else if (!(pr_flags & PR_IP4_USER)) {
1835 				pr->pr_flags |= ppr->pr_flags & PR_IP4;
1836 				prison_ip_dup(ppr, pr, PR_INET);
1837 			}
1838 #endif
1839 #ifdef INET6
1840 			if (!(ch_flags & PR_IP6_USER))
1841 				pr->pr_flags |= PR_IP6 | PR_IP6_USER;
1842 			else if (!(pr_flags & PR_IP6_USER)) {
1843 				pr->pr_flags |= ppr->pr_flags & PR_IP6;
1844 				prison_ip_dup(ppr, pr, PR_INET6);
1845 			}
1846 #endif
1847 		}
1848 #endif
1849 		/* Source address selection is always on by default. */
1850 		pr->pr_flags |= _PR_IP_SADDRSEL;
1851 
1852 		pr->pr_securelevel = ppr->pr_securelevel;
1853 		pr->pr_allow = JAIL_DEFAULT_ALLOW & ppr->pr_allow;
1854 		pr->pr_enforce_statfs = jail_default_enforce_statfs;
1855 		pr->pr_devfs_rsnum = ppr->pr_devfs_rsnum;
1856 
1857 		pr->pr_osreldate = osreldt ? osreldt : ppr->pr_osreldate;
1858 		if (osrelstr == NULL)
1859 			strlcpy(pr->pr_osrelease, ppr->pr_osrelease,
1860 			    sizeof(pr->pr_osrelease));
1861 		else
1862 			strlcpy(pr->pr_osrelease, osrelstr,
1863 			    sizeof(pr->pr_osrelease));
1864 
1865 #ifdef VIMAGE
1866 		/*
1867 		 * Allocate a new vnet if specified.
1868 		 *
1869 		 * Set PR_VNET now if so, so that the vnet is disposed of
1870 		 * properly when the jail is destroyed.
1871 		 */
1872 		if (pr_flags & PR_VNET) {
1873 			pr->pr_flags |= PR_VNET;
1874 			pr->pr_vnet = vnet_alloc();
1875 		} else {
1876 			pr->pr_vnet = ppr->pr_vnet;
1877 		}
1878 #endif
1879 		/*
1880 		 * Allocate a dedicated cpuset for each jail.
1881 		 * Unlike other initial settings, this may return an error.
1882 		 */
1883 		error = cpuset_create_root(ppr, &pr->pr_cpuset);
1884 		if (error)
1885 			goto done_deref;
1886 
1887 #ifdef MAC
1888 		error = mac_prison_init(pr, M_WAITOK);
1889 		MPASS(error == 0);
1890 
1891 		mtx_assert(&pr->pr_mtx, MA_OWNED);
1892 #else
1893 		mtx_lock(&pr->pr_mtx);
1894 #endif
1895 		drflags |= PD_LOCKED;
1896 	} else {
1897 		/*
1898 		 * Grab a reference for existing prisons, to ensure they
1899 		 * continue to exist for the duration of the call.
1900 		 */
1901 		if (!(drflags & PD_DEREF)) {
1902 			prison_hold(pr);
1903 			drflags |= PD_DEREF;
1904 		}
1905 #ifdef MAC
1906 		error = mac_prison_check_set(td->td_ucred, pr, opts, flags);
1907 		if (error != 0)
1908 			goto done_deref;
1909 #endif
1910 #if defined(VIMAGE) && (defined(INET) || defined(INET6))
1911 		if ((pr->pr_flags & PR_VNET) &&
1912 		    (ch_flags & (PR_IP4_USER | PR_IP6_USER))) {
1913 			error = EINVAL;
1914 			vfs_opterror(opts,
1915 			    "vnet jails cannot have IP address restrictions");
1916 			goto done_deref;
1917 		}
1918 #endif
1919 #ifdef INET
1920 		if (PR_IP4_USER & ch_flags & (pr_flags ^ pr->pr_flags)) {
1921 			error = EINVAL;
1922 			vfs_opterror(opts,
1923 			    "ip4 cannot be changed after creation");
1924 			goto done_deref;
1925 		}
1926 #endif
1927 #ifdef INET6
1928 		if (PR_IP6_USER & ch_flags & (pr_flags ^ pr->pr_flags)) {
1929 			error = EINVAL;
1930 			vfs_opterror(opts,
1931 			    "ip6 cannot be changed after creation");
1932 			goto done_deref;
1933 		}
1934 #endif
1935 	}
1936 
1937 	/* Do final error checking before setting anything. */
1938 	if (gotslevel) {
1939 		if (slevel < ppr->pr_securelevel) {
1940 			error = EPERM;
1941 			goto done_deref;
1942 		}
1943 	}
1944 	if (gotchildmax) {
1945 		if (childmax >= ppr->pr_childmax) {
1946 			error = EPERM;
1947 			goto done_deref;
1948 		}
1949 	}
1950 	if (gotenforce) {
1951 		if (enforce < ppr->pr_enforce_statfs) {
1952 			error = EPERM;
1953 			goto done_deref;
1954 		}
1955 	}
1956 	if (gotrsnum) {
1957 		/*
1958 		 * devfs_rsnum is a uint16_t
1959 		 */
1960 		if (rsnum < 0 || rsnum > 65535) {
1961 			error = EINVAL;
1962 			goto done_deref;
1963 		}
1964 		/*
1965 		 * Nested jails always inherit parent's devfs ruleset
1966 		 */
1967 		if (jailed(td->td_ucred)) {
1968 			if (rsnum > 0 && rsnum != ppr->pr_devfs_rsnum) {
1969 				error = EPERM;
1970 				goto done_deref;
1971 			} else
1972 				rsnum = ppr->pr_devfs_rsnum;
1973 		}
1974 	}
1975 #ifdef INET
1976 	if (ip4s > 0) {
1977 		if ((ppr->pr_flags & PR_IP4) &&
1978 		    !prison_ip_parent_match(ppr->pr_addrs[PR_INET], ip4,
1979 		    PR_INET)) {
1980 			error = EPERM;
1981 			goto done_deref;
1982 		}
1983 		if (!prison_ip_conflict_check(ppr, pr, ip4, PR_INET)) {
1984 			error = EADDRINUSE;
1985 			vfs_opterror(opts, "IPv4 addresses clash");
1986 			goto done_deref;
1987 		}
1988 	}
1989 #endif
1990 #ifdef INET6
1991 	if (ip6s > 0) {
1992 		if ((ppr->pr_flags & PR_IP6) &&
1993 		    !prison_ip_parent_match(ppr->pr_addrs[PR_INET6], ip6,
1994 		    PR_INET6)) {
1995 			error = EPERM;
1996 			goto done_deref;
1997 		}
1998 		if (!prison_ip_conflict_check(ppr, pr, ip6, PR_INET6)) {
1999 			error = EADDRINUSE;
2000 			vfs_opterror(opts, "IPv6 addresses clash");
2001 			goto done_deref;
2002 		}
2003 	}
2004 #endif
2005 	onamelen = namelen = 0;
2006 	if (namelc != NULL) {
2007 		/* Give a default name of the jid.  Also allow the name to be
2008 		 * explicitly the jid - but not any other number, and only in
2009 		 * normal form (no leading zero/etc).
2010 		 */
2011 		if (namelc[0] == '\0')
2012 			snprintf(namelc = numbuf, sizeof(numbuf), "%d", jid);
2013 		else if ((strtoul(namelc, &p, 10) != jid ||
2014 			  namelc[0] < '1' || namelc[0] > '9') && *p == '\0') {
2015 			error = EINVAL;
2016 			vfs_opterror(opts,
2017 			    "name cannot be numeric (unless it is the jid)");
2018 			goto done_deref;
2019 		}
2020 		/*
2021 		 * Make sure the name isn't too long for the prison or its
2022 		 * children.
2023 		 */
2024 		pnamelen = (ppr == &prison0) ? 0 : strlen(ppr->pr_name) + 1;
2025 		onamelen = strlen(pr->pr_name + pnamelen);
2026 		namelen = strlen(namelc);
2027 		if (pnamelen + namelen + 1 > sizeof(pr->pr_name)) {
2028 			error = ENAMETOOLONG;
2029 			goto done_deref;
2030 		}
2031 		FOREACH_PRISON_DESCENDANT(pr, tpr, descend) {
2032 			if (strlen(tpr->pr_name) + (namelen - onamelen) >=
2033 			    sizeof(pr->pr_name)) {
2034 				error = ENAMETOOLONG;
2035 				goto done_deref;
2036 			}
2037 		}
2038 	}
2039 	pr_allow_diff = pr_allow & ~ppr->pr_allow;
2040 	if (pr_allow_diff & ~PR_ALLOW_DIFFERENCES) {
2041 		error = EPERM;
2042 		goto done_deref;
2043 	}
2044 
2045 	/*
2046 	 * Let modules check their parameters.  This requires unlocking and
2047 	 * then re-locking the prison, but this is still a valid state as long
2048 	 * as allprison_lock remains xlocked.
2049 	 */
2050 	mtx_unlock(&pr->pr_mtx);
2051 	drflags &= ~PD_LOCKED;
2052 	error = osd_jail_call(pr, PR_METHOD_CHECK, opts);
2053 	if (error != 0)
2054 		goto done_deref;
2055 	mtx_lock(&pr->pr_mtx);
2056 	drflags |= PD_LOCKED;
2057 
2058 	/* At this point, all valid parameters should have been noted. */
2059 	TAILQ_FOREACH(opt, opts, link) {
2060 		if (!opt->seen && strcmp(opt->name, "errmsg")) {
2061 			error = EINVAL;
2062 			vfs_opterror(opts, "unknown parameter: %s", opt->name);
2063 			goto done_deref;
2064 		}
2065 	}
2066 	maybe_changed = true;
2067 
2068 	/* Set the parameters of the prison. */
2069 #ifdef INET
2070 	redo_ip4 = false;
2071 	if (pr_flags & PR_IP4_USER) {
2072 		pr->pr_flags |= PR_IP4;
2073 		prison_ip_set(pr, PR_INET, ip4);
2074 		ip4 = NULL;
2075 		FOREACH_PRISON_DESCENDANT_LOCKED(pr, tpr, descend) {
2076 #ifdef VIMAGE
2077 			if (tpr->pr_flags & PR_VNET) {
2078 				descend = 0;
2079 				continue;
2080 			}
2081 #endif
2082 			if (!prison_ip_restrict(tpr, PR_INET, NULL)) {
2083 				redo_ip4 = true;
2084 				descend = 0;
2085 			}
2086 		}
2087 	}
2088 #endif
2089 #ifdef INET6
2090 	redo_ip6 = false;
2091 	if (pr_flags & PR_IP6_USER) {
2092 		pr->pr_flags |= PR_IP6;
2093 		prison_ip_set(pr, PR_INET6, ip6);
2094 		ip6 = NULL;
2095 		FOREACH_PRISON_DESCENDANT_LOCKED(pr, tpr, descend) {
2096 #ifdef VIMAGE
2097 			if (tpr->pr_flags & PR_VNET) {
2098 				descend = 0;
2099 				continue;
2100 			}
2101 #endif
2102 			if (!prison_ip_restrict(tpr, PR_INET6, NULL)) {
2103 				redo_ip6 = true;
2104 				descend = 0;
2105 			}
2106 		}
2107 	}
2108 #endif
2109 	if (gotslevel) {
2110 		pr->pr_securelevel = slevel;
2111 		/* Set all child jails to be at least this level. */
2112 		FOREACH_PRISON_DESCENDANT_LOCKED(pr, tpr, descend)
2113 			if (tpr->pr_securelevel < slevel)
2114 				tpr->pr_securelevel = slevel;
2115 	}
2116 	if (gotchildmax) {
2117 		pr->pr_childmax = childmax;
2118 		/* Set all child jails to under this limit. */
2119 		FOREACH_PRISON_DESCENDANT_LOCKED_LEVEL(pr, tpr, descend, level)
2120 			if (tpr->pr_childmax > childmax - level)
2121 				tpr->pr_childmax = childmax > level
2122 				    ? childmax - level : 0;
2123 	}
2124 	if (gotenforce) {
2125 		pr->pr_enforce_statfs = enforce;
2126 		/* Pass this restriction on to the children. */
2127 		FOREACH_PRISON_DESCENDANT_LOCKED(pr, tpr, descend)
2128 			if (tpr->pr_enforce_statfs < enforce)
2129 				tpr->pr_enforce_statfs = enforce;
2130 	}
2131 	if (gotrsnum) {
2132 		pr->pr_devfs_rsnum = rsnum;
2133 		/* Pass this restriction on to the children. */
2134 		FOREACH_PRISON_DESCENDANT_LOCKED(pr, tpr, descend)
2135 			tpr->pr_devfs_rsnum = rsnum;
2136 	}
2137 	if (namelc != NULL) {
2138 		if (ppr == &prison0)
2139 			strlcpy(pr->pr_name, namelc, sizeof(pr->pr_name));
2140 		else
2141 			snprintf(pr->pr_name, sizeof(pr->pr_name), "%s.%s",
2142 			    ppr->pr_name, namelc);
2143 		/* Change this component of child names. */
2144 		FOREACH_PRISON_DESCENDANT_LOCKED(pr, tpr, descend) {
2145 			bcopy(tpr->pr_name + onamelen, tpr->pr_name + namelen,
2146 			    strlen(tpr->pr_name + onamelen) + 1);
2147 			bcopy(pr->pr_name, tpr->pr_name, namelen);
2148 		}
2149 	}
2150 	if (path != NULL) {
2151 		/* Try to keep a real-rooted full pathname. */
2152 		strlcpy(pr->pr_path, path, sizeof(pr->pr_path));
2153 		pr->pr_root = root;
2154 		root = NULL;
2155 	}
2156 	if (PR_HOST & ch_flags & ~pr_flags) {
2157 		if (pr->pr_flags & PR_HOST) {
2158 			/*
2159 			 * Copy the parent's host info.  As with pr_ip4 above,
2160 			 * the lack of a lock on the parent is not a problem;
2161 			 * it is always set with allprison_lock at least
2162 			 * shared, and is held exclusively here.
2163 			 */
2164 			strlcpy(pr->pr_hostname, pr->pr_parent->pr_hostname,
2165 			    sizeof(pr->pr_hostname));
2166 			strlcpy(pr->pr_domainname, pr->pr_parent->pr_domainname,
2167 			    sizeof(pr->pr_domainname));
2168 			strlcpy(pr->pr_hostuuid, pr->pr_parent->pr_hostuuid,
2169 			    sizeof(pr->pr_hostuuid));
2170 			pr->pr_hostid = pr->pr_parent->pr_hostid;
2171 		}
2172 	} else if (host != NULL || domain != NULL || uuid != NULL || gothid) {
2173 		/* Set this prison, and any descendants without PR_HOST. */
2174 		if (host != NULL)
2175 			strlcpy(pr->pr_hostname, host, sizeof(pr->pr_hostname));
2176 		if (domain != NULL)
2177 			strlcpy(pr->pr_domainname, domain,
2178 			    sizeof(pr->pr_domainname));
2179 		if (uuid != NULL)
2180 			strlcpy(pr->pr_hostuuid, uuid, sizeof(pr->pr_hostuuid));
2181 		if (gothid)
2182 			pr->pr_hostid = hid;
2183 		FOREACH_PRISON_DESCENDANT_LOCKED(pr, tpr, descend) {
2184 			if (tpr->pr_flags & PR_HOST)
2185 				descend = 0;
2186 			else {
2187 				if (host != NULL)
2188 					strlcpy(tpr->pr_hostname,
2189 					    pr->pr_hostname,
2190 					    sizeof(tpr->pr_hostname));
2191 				if (domain != NULL)
2192 					strlcpy(tpr->pr_domainname,
2193 					    pr->pr_domainname,
2194 					    sizeof(tpr->pr_domainname));
2195 				if (uuid != NULL)
2196 					strlcpy(tpr->pr_hostuuid,
2197 					    pr->pr_hostuuid,
2198 					    sizeof(tpr->pr_hostuuid));
2199 				if (gothid)
2200 					tpr->pr_hostid = hid;
2201 			}
2202 		}
2203 	}
2204 	pr->pr_allow = (pr->pr_allow & ~ch_allow) | pr_allow;
2205 	if ((tallow = ch_allow & ~pr_allow))
2206 		prison_set_allow_locked(pr, tallow, 0);
2207 	/*
2208 	 * Persistent prisons get an extra reference, and prisons losing their
2209 	 * persist flag lose that reference.
2210 	 */
2211 	if (ch_flags & PR_PERSIST & (pr_flags ^ pr->pr_flags)) {
2212 		if (pr_flags & PR_PERSIST) {
2213 			prison_hold(pr);
2214 			/*
2215 			 * This may be a new prison's first user reference,
2216 			 * but wait to call it alive until after OSD calls
2217 			 * have had a chance to run (and perhaps to fail).
2218 			 */
2219 			refcount_acquire(&pr->pr_uref);
2220 		} else {
2221 			drflags |= PD_DEUREF;
2222 			prison_free_not_last(pr);
2223 		}
2224 	}
2225 	pr->pr_flags = (pr->pr_flags & ~ch_flags) | pr_flags;
2226 
2227 #ifdef MAC
2228 	/* Apply any request MAC label before we let modules do their work. */
2229 	if (gotmaclabel) {
2230 		error = mac_set_prison_core(td, pr, mac_set_prison_data);
2231 		if (error) {
2232 			vfs_opterror(opts, "mac relabel denied");
2233 			goto done_deref;
2234 		}
2235 	}
2236 #endif
2237 	mtx_unlock(&pr->pr_mtx);
2238 	drflags &= ~PD_LOCKED;
2239 	/*
2240 	 * Any errors past this point will need to de-persist newly created
2241 	 * prisons, as well as call remove methods.
2242 	 */
2243 	if (created)
2244 		drflags |= PD_KILL;
2245 
2246 #ifdef RACCT
2247 	if (racct_enable && created)
2248 		prison_racct_attach(pr);
2249 #endif
2250 
2251 	/* Locks may have prevented a complete restriction of child IP
2252 	 * addresses.  If so, allocate some more memory and try again.
2253 	 */
2254 #ifdef INET
2255 	while (redo_ip4) {
2256 		ip4s = pr->pr_addrs[PR_INET]->ips;
2257 		MPASS(ip4 == NULL);
2258 		ip4 = prison_ip_alloc(PR_INET, ip4s, M_WAITOK);
2259 		mtx_lock(&pr->pr_mtx);
2260 		redo_ip4 = false;
2261 		FOREACH_PRISON_DESCENDANT_LOCKED(pr, tpr, descend) {
2262 #ifdef VIMAGE
2263 			if (tpr->pr_flags & PR_VNET) {
2264 				descend = 0;
2265 				continue;
2266 			}
2267 #endif
2268 			if (!prison_ip_restrict(tpr, PR_INET, &ip4))
2269 				redo_ip4 = true;
2270 		}
2271 		mtx_unlock(&pr->pr_mtx);
2272 	}
2273 #endif
2274 #ifdef INET6
2275 	while (redo_ip6) {
2276 		ip6s = pr->pr_addrs[PR_INET6]->ips;
2277 		MPASS(ip6 == NULL);
2278 		ip6 = prison_ip_alloc(PR_INET6, ip6s, M_WAITOK);
2279 		mtx_lock(&pr->pr_mtx);
2280 		redo_ip6 = false;
2281 		FOREACH_PRISON_DESCENDANT_LOCKED(pr, tpr, descend) {
2282 #ifdef VIMAGE
2283 			if (tpr->pr_flags & PR_VNET) {
2284 				descend = 0;
2285 				continue;
2286 			}
2287 #endif
2288 			if (!prison_ip_restrict(tpr, PR_INET6, &ip6))
2289 				redo_ip6 = true;
2290 		}
2291 		mtx_unlock(&pr->pr_mtx);
2292 	}
2293 #endif
2294 
2295 	/* Let the modules do their work. */
2296 	if (created) {
2297 		error = osd_jail_call(pr, PR_METHOD_CREATE, opts);
2298 		if (error)
2299 			goto done_deref;
2300 	}
2301 	error = osd_jail_call(pr, PR_METHOD_SET, opts);
2302 	if (error)
2303 		goto done_deref;
2304 
2305 	/*
2306 	 * A new prison is now ready to be seen; either it has gained a user
2307 	 * reference via persistence, or is about to gain one via attachment.
2308 	 */
2309 	if (created) {
2310 		sx_assert(&allprison_lock, SX_XLOCKED);
2311 		prison_knote(ppr, NOTE_JAIL_CHILD | pr->pr_id);
2312 #ifdef MAC
2313 		/*
2314 		 * Note that mac_prison_created() assumes that it's called in a
2315 		 * sleepable context.
2316 		 */
2317 		mac_prison_created(td->td_ucred, pr);
2318 #endif
2319 		mtx_lock(&pr->pr_mtx);
2320 		drflags |= PD_LOCKED;
2321 		pr->pr_state = PRISON_STATE_ALIVE;
2322 	}
2323 
2324 	/*
2325 	 * Attach this process to the prison if requested.  This will
2326 	 * unlock allprison_lock, meaning changes are now user-visible.
2327 	 */
2328 	if (flags & JAIL_ATTACH) {
2329 #ifdef MAC
2330 		error = mac_prison_check_attach(td->td_ucred, pr);
2331 		if (error != 0) {
2332 			vfs_opterror(opts,
2333 			    "attach operation denied by MAC policy");
2334 			goto done_deref;
2335 		}
2336 #endif
2337 		error = do_jail_attach(td, pr, &drflags);
2338 		if (error) {
2339 			vfs_opterror(opts, "attach failed");
2340 			goto done_deref;
2341 		}
2342 	}
2343 
2344 #ifdef RACCT
2345 	if (racct_enable && !created) {
2346 		if (drflags & PD_LOCKED) {
2347 			mtx_unlock(&pr->pr_mtx);
2348 			drflags &= ~PD_LOCKED;
2349 		}
2350 		if (drflags & PD_LIST_XLOCKED) {
2351 			sx_xunlock(&allprison_lock);
2352 			drflags &= ~PD_LIST_XLOCKED;
2353 		}
2354 		prison_racct_modify(pr);
2355 	}
2356 #endif
2357 
2358 	if (created && pr != &prison0 && (pr->pr_allow & PR_ALLOW_NFSD) != 0 &&
2359 	    (pr->pr_root->v_vflag & VV_ROOT) == 0)
2360 		printf("Warning jail jid=%d: mountd/nfsd requires a separate"
2361 		   " file system\n", pr->pr_id);
2362 
2363 	/*
2364 	 * Now that the prison is fully created without error, set the
2365 	 * jail descriptor if one was requested.  This is the only
2366 	 * parameter that is returned to the caller (except the error
2367 	 * message).
2368 	 */
2369 	if (jfd_out >= 0) {
2370 		if (!(drflags & PD_LOCKED)) {
2371 			mtx_lock(&pr->pr_mtx);
2372 			drflags |= PD_LOCKED;
2373 		}
2374 		jfd_pos = 2 * vfs_getopt_pos(opts, JAIL_PARAM_DESC) + 1;
2375 		if (optuio->uio_segflg == UIO_SYSSPACE)
2376 			*(int*)optuio->uio_iov[jfd_pos].iov_base = jfd_out;
2377 		else
2378 			(void)copyout(&jfd_out,
2379 			    optuio->uio_iov[jfd_pos].iov_base, sizeof(jfd_out));
2380 		jaildesc_set_prison(jfp_out, pr);
2381 	}
2382 
2383 	drflags &= ~PD_KILL;
2384 	td->td_retval[0] = pr->pr_id;
2385 
2386  done_deref:
2387 	/*
2388 	 * Report changes to kevent.  This can happen even if the
2389 	 * system call fails, as changes might have been made before
2390 	 * the failure.
2391 	 */
2392 	if (maybe_changed && !created)
2393 		prison_knote(pr, NOTE_JAIL_SET);
2394 	/* Release any temporary prison holds and/or locks. */
2395 	if (pr != NULL)
2396 		prison_deref(pr, drflags);
2397 	else if (drflags & PD_LIST_SLOCKED)
2398 		sx_sunlock(&allprison_lock);
2399 	else if (drflags & PD_LIST_XLOCKED)
2400 		sx_xunlock(&allprison_lock);
2401 	if (root != NULL)
2402 		vrele(root);
2403  done_errmsg:
2404 	if (error) {
2405 		/* Write the error message back to userspace. */
2406 		if (vfs_getopt(opts, JAIL_PARAM_ERRMSG, (void **)&errmsg,
2407 		    &errmsg_len) == 0 && errmsg_len > 0) {
2408 			errmsg_pos = 2 * vfs_getopt_pos(opts, JAIL_PARAM_ERRMSG) + 1;
2409 			if (optuio->uio_segflg == UIO_SYSSPACE)
2410 				bcopy(errmsg,
2411 				    optuio->uio_iov[errmsg_pos].iov_base,
2412 				    errmsg_len);
2413 			else
2414 				(void)copyout(errmsg,
2415 				    optuio->uio_iov[errmsg_pos].iov_base,
2416 				    errmsg_len);
2417 		}
2418 	}
2419  done_free:
2420 	/* Clean up other resources. */
2421 #ifdef INET
2422 	prison_ip_free(ip4);
2423 #endif
2424 #ifdef INET6
2425 	prison_ip_free(ip6);
2426 #endif
2427 #ifdef MAC
2428 	if (mac_set_prison_data != NULL)
2429 		mac_set_prison_finish(td, error == 0, mac_set_prison_data);
2430 #endif
2431 	if (jfp_out != NULL)
2432 		fdrop(jfp_out, td);
2433 	if (error && jfd_out >= 0)
2434 		(void)kern_close(td, jfd_out);
2435 	if (g_path != NULL)
2436 		free(g_path, M_TEMP);
2437 	if (opts != NULL)
2438 		vfs_freeopts(opts);
2439 	prison_free(mypr);
2440 	if (flags & JAIL_ATTACH)
2441 		prison_attach_thread_single_end(td);
2442 	return (error);
2443 }
2444 
2445 /*
2446  * Find the next available prison ID.  Return the ID on success, or zero
2447  * on failure.  Also set a pointer to the allprison list entry the prison
2448  * should be inserted before.
2449  */
2450 static int
2451 get_next_prid(struct prison **insprp)
2452 {
2453 	struct prison *inspr;
2454 	int jid, maxid;
2455 
2456 	jid = lastprid % JAIL_MAX + 1;
2457 	if (TAILQ_EMPTY(&allprison) ||
2458 	    TAILQ_LAST(&allprison, prisonlist)->pr_id < jid) {
2459 		/*
2460 		 * A common case is for all jails to be implicitly numbered,
2461 		 * which means they'll go on the end of the list, at least
2462 		 * for the first JAIL_MAX times.
2463 		 */
2464 		inspr = NULL;
2465 	} else {
2466 		/*
2467 		 * Take two passes through the allprison list: first starting
2468 		 * with the proposed jid, then ending with it.
2469 		 */
2470 		for (maxid = JAIL_MAX; maxid != 0; ) {
2471 			TAILQ_FOREACH(inspr, &allprison, pr_list) {
2472 				if (inspr->pr_id < jid)
2473 					continue;
2474 				if (inspr->pr_id > jid) {
2475 					/* Found an opening. */
2476 					maxid = 0;
2477 					break;
2478 				}
2479 				if (++jid > maxid) {
2480 					if (lastprid == maxid || lastprid == 0)
2481 					{
2482 						/*
2483 						 * The entire legal range
2484 						 * has been traversed
2485 						 */
2486 						return 0;
2487 					}
2488 					/* Try again from the start. */
2489 					jid = 1;
2490 					maxid = lastprid;
2491 					break;
2492 				}
2493 			}
2494 			if (inspr == NULL) {
2495 				/* Found room at the end of the list. */
2496 				break;
2497 			}
2498 		}
2499 	}
2500 	*insprp = inspr;
2501 	lastprid = jid;
2502 	return (jid);
2503 }
2504 
2505 /*
2506  * Find the next available ID for a renumbered dead prison.  This is the same
2507  * as get_next_prid, but counting backward from the end of the range.
2508  */
2509 static int
2510 get_next_deadid(struct prison **dinsprp)
2511 {
2512 	struct prison *dinspr;
2513 	int deadid, minid;
2514 
2515 	deadid = lastdeadid ? lastdeadid - 1 : JAIL_MAX;
2516 	/*
2517 	 * Take two reverse passes through the allprison list: first
2518 	 * starting with the proposed deadid, then ending with it.
2519 	 */
2520 	for (minid = 1; minid != 0; ) {
2521 		TAILQ_FOREACH_REVERSE(dinspr, &allprison, prisonlist, pr_list) {
2522 			if (dinspr->pr_id > deadid)
2523 				continue;
2524 			if (dinspr->pr_id < deadid) {
2525 				/* Found an opening. */
2526 				minid = 0;
2527 				break;
2528 			}
2529 			if (--deadid < minid) {
2530 				if (lastdeadid == minid || lastdeadid == 0)
2531 				{
2532 					/*
2533 					 * The entire legal range
2534 					 * has been traversed
2535 					 */
2536 					return 0;
2537 				}
2538 				/* Try again from the end. */
2539 				deadid = JAIL_MAX;
2540 				minid = lastdeadid;
2541 				break;
2542 			}
2543 		}
2544 		if (dinspr == NULL) {
2545 			/* Found room at the beginning of the list. */
2546 			break;
2547 		}
2548 	}
2549 	*dinsprp = dinspr;
2550 	lastdeadid = deadid;
2551 	return (deadid);
2552 }
2553 
2554 /*
2555  * struct jail_get_args {
2556  *	struct iovec *iovp;
2557  *	unsigned int iovcnt;
2558  *	int flags;
2559  * };
2560  */
2561 int
2562 sys_jail_get(struct thread *td, struct jail_get_args *uap)
2563 {
2564 	struct uio *auio;
2565 	int error;
2566 
2567 	/* Check that we have an even number of iovecs. */
2568 	if (uap->iovcnt & 1)
2569 		return (EINVAL);
2570 
2571 	error = copyinuio(uap->iovp, uap->iovcnt, &auio);
2572 	if (error)
2573 		return (error);
2574 	error = kern_jail_get(td, auio, uap->flags);
2575 	if (error == 0)
2576 		error = copyout(auio->uio_iov, uap->iovp,
2577 		    uap->iovcnt * sizeof(struct iovec));
2578 	freeuio(auio);
2579 	return (error);
2580 }
2581 
2582 int
2583 kern_jail_get(struct thread *td, struct uio *optuio, int flags)
2584 {
2585 	struct bool_flags *bf;
2586 	struct file *jfp_out;
2587 	struct jailsys_flags *jsf;
2588 	struct prison *pr, *mypr;
2589 	struct vfsopt *opt;
2590 	struct vfsoptlist *opts;
2591 	char *errmsg, *name;
2592 	int drflags, error, errmsg_len, errmsg_pos, i, jid, len, pos;
2593 	int jfd_in, jfd_out;
2594 	unsigned f;
2595 
2596 	if (flags & ~JAIL_GET_MASK)
2597 		return (EINVAL);
2598 	if ((flags & (JAIL_USE_DESC | JAIL_AT_DESC)) ==
2599 	    (JAIL_USE_DESC | JAIL_AT_DESC))
2600 		return (EINVAL);
2601 
2602 	/* Get the parameter list. */
2603 	error = vfs_buildopts(optuio, &opts);
2604 	if (error)
2605 		return (error);
2606 	errmsg_pos = vfs_getopt_pos(opts, JAIL_PARAM_ERRMSG);
2607 	mypr = td->td_ucred->cr_prison;
2608 	prison_hold(mypr);
2609 	pr = NULL;
2610 	jfp_out = NULL;
2611 	jfd_out = -1;
2612 
2613 	/*
2614 	 * Find the prison specified by one of: desc, lastjid, jid, name.
2615 	 */
2616 	sx_slock(&allprison_lock);
2617 	drflags = PD_LIST_SLOCKED;
2618 
2619 	error = vfs_copyopt(opts, JAIL_PARAM_DESC, &jfd_in, sizeof(jfd_in));
2620 	if (error == ENOENT) {
2621 		if (flags & (JAIL_AT_DESC | JAIL_GET_DESC | JAIL_OWN_DESC)) {
2622 			vfs_opterror(opts, "missing desc");
2623 			goto done;
2624 		}
2625 	} else if (error == 0) {
2626 		if (!(flags & (JAIL_USE_DESC | JAIL_AT_DESC | JAIL_GET_DESC |
2627 		    JAIL_OWN_DESC))) {
2628 			error = EINVAL;
2629 			vfs_opterror(opts, "unexpected desc");
2630 			goto done;
2631 		}
2632 		if (flags & JAIL_USE_DESC) {
2633 			/* Get the jail from its descriptor. */
2634 			error = jaildesc_find(td, jfd_in, &pr, NULL);
2635 			if (error) {
2636 				vfs_opterror(opts, error == ENOENT ?
2637 				    "descriptor to dead jail" :
2638 				    "not a jail descriptor");
2639 				goto done;
2640 			}
2641 			drflags |= PD_DEREF;
2642 			mtx_lock(&pr->pr_mtx);
2643 			drflags |= PD_LOCKED;
2644 			goto found_prison;
2645 		}
2646 		if (flags & JAIL_AT_DESC) {
2647 			/* Look up jails based on the descriptor's prison. */
2648 			struct prison *jdpr;
2649 
2650 			error = jaildesc_find(td, jfd_in, &jdpr, NULL);
2651 			if (error != 0) {
2652 				vfs_opterror(opts, error == ENOENT ?
2653 				    "descriptor to dead jail" :
2654 				    "not a jail descriptor");
2655 				goto done;
2656 			}
2657 			prison_free(mypr);
2658 			mypr = jdpr;
2659 		}
2660 		if (flags & (JAIL_GET_DESC | JAIL_OWN_DESC)) {
2661 			/* Allocate a jail descriptor to return later. */
2662 			error = jaildesc_alloc(td, &jfp_out, &jfd_out,
2663 				flags & JAIL_OWN_DESC);
2664 			if (error)
2665 				goto done;
2666 		}
2667 	} else
2668 		goto done;
2669 
2670 	error = vfs_copyopt(opts, JAIL_PARAM_LASTJID, &jid, sizeof(jid));
2671 	if (error == 0) {
2672 		TAILQ_FOREACH(pr, &allprison, pr_list) {
2673 			if (pr->pr_id > jid &&
2674 			    ((flags & JAIL_DYING) || prison_isalive(pr)) &&
2675 			    prison_ischild(mypr, pr)) {
2676 				mtx_lock(&pr->pr_mtx);
2677 				drflags |= PD_LOCKED;
2678 #ifdef MAC
2679 				/*
2680 				 * We special-case this one check because we
2681 				 * don't want MAC to break jail enumeration.  We
2682 				 * need to just move on to the next accessible
2683 				 * and alive prison.
2684 				 */
2685 				error = mac_prison_check_get(td->td_ucred, pr,
2686 				    opts, flags);
2687 				if (error != 0) {
2688 					mtx_unlock(&pr->pr_mtx);
2689 					drflags &= ~PD_LOCKED;
2690 					continue;
2691 				}
2692 
2693 				/*
2694 				 * Avoid potentially expensive trip back into
2695 				 * the MAC framework.
2696 				 */
2697 				goto found_prison_nomac_alive;
2698 #else
2699 				goto found_prison;
2700 #endif
2701 			}
2702 		}
2703 		error = ENOENT;
2704 		vfs_opterror(opts, "no jail after %d", jid);
2705 		goto done;
2706 	} else if (error != ENOENT)
2707 		goto done;
2708 
2709 	error = vfs_copyopt(opts, JAIL_PARAM_JID, &jid, sizeof(jid));
2710 	if (error == 0) {
2711 		if (jid != 0) {
2712 			pr = prison_find_child(mypr, jid);
2713 			if (pr != NULL) {
2714 				drflags |= PD_LOCKED;
2715 				goto found_prison;
2716 			}
2717 			error = ENOENT;
2718 			vfs_opterror(opts, "jail %d not found", jid);
2719 			goto done;
2720 		}
2721 	} else if (error != ENOENT)
2722 		goto done;
2723 
2724 	error = vfs_getopt(opts, JAIL_PARAM_NAME, (void **)&name, &len);
2725 	if (error == 0) {
2726 		if (len == 0 || name[len - 1] != '\0') {
2727 			error = EINVAL;
2728 			goto done;
2729 		}
2730 		pr = prison_find_name(mypr, name);
2731 		if (pr != NULL) {
2732 			drflags |= PD_LOCKED;
2733 			goto found_prison;
2734 		}
2735 		error = ENOENT;
2736 		vfs_opterror(opts, "jail \"%s\" not found", name);
2737 		goto done;
2738 	} else if (error != ENOENT)
2739 		goto done;
2740 
2741 	vfs_opterror(opts, "no jail specified");
2742 	error = ENOENT;
2743 	goto done;
2744 
2745  found_prison:
2746 #ifdef MAC
2747 	error = mac_prison_check_get(td->td_ucred, pr, opts, flags);
2748 	if (error != 0)
2749 		goto done;
2750 #endif
2751 	if (!(prison_isalive(pr) || (flags & JAIL_DYING))) {
2752 		error = ENOENT;
2753 		if (pr->pr_name[0] != '0' && isdigit(pr->pr_name[0])) {
2754 			vfs_opterror(opts, "jail %d is dying",
2755 			    pr->pr_id);
2756 		} else {
2757 			vfs_opterror(opts, "jail \"%s\" (%d) is dying",
2758 			    pr->pr_name, pr->pr_id);
2759 		}
2760 		goto done;
2761 	}
2762 #ifdef MAC
2763  found_prison_nomac_alive:
2764 #endif
2765 	/* Get the parameters of the prison. */
2766 	if (!(drflags & PD_DEREF)) {
2767 		prison_hold(pr);
2768 		drflags |= PD_DEREF;
2769 	}
2770 	td->td_retval[0] = pr->pr_id;
2771 	if (jfd_out >= 0) {
2772 		error = vfs_setopt(opts, JAIL_PARAM_DESC, &jfd_out, sizeof(jfd_out));
2773 		if (error != 0 && error != ENOENT)
2774 			goto done;
2775 		jaildesc_set_prison(jfp_out, pr);
2776 	}
2777 	error = vfs_setopt(opts, JAIL_PARAM_JID, &pr->pr_id, sizeof(pr->pr_id));
2778 	if (error != 0 && error != ENOENT)
2779 		goto done;
2780 	i = (pr->pr_parent == mypr) ? 0 : pr->pr_parent->pr_id;
2781 	error = vfs_setopt(opts, JAIL_PARAM_PARENT, &i, sizeof(i));
2782 	if (error != 0 && error != ENOENT)
2783 		goto done;
2784 	error = vfs_setopts(opts, JAIL_PARAM_NAME, prison_name(mypr, pr));
2785 	if (error != 0 && error != ENOENT)
2786 		goto done;
2787 	error = vfs_setopt(opts, JAIL_PARAM_CPUSET_ID, &pr->pr_cpuset->cs_id,
2788 	    sizeof(pr->pr_cpuset->cs_id));
2789 	if (error != 0 && error != ENOENT)
2790 		goto done;
2791 	error = vfs_setopts(opts, JAIL_PARAM_PATH, prison_path(mypr, pr));
2792 	if (error != 0 && error != ENOENT)
2793 		goto done;
2794 #ifdef INET
2795 	error = vfs_setopt_part(opts, JAIL_PARAM_IP4_ADDR,
2796 	    pr->pr_addrs[PR_INET]->pr_ip,
2797 	    pr->pr_addrs[PR_INET] ? pr->pr_addrs[PR_INET]->ips *
2798 	    pr_families[PR_INET].size : 0 );
2799 	if (error != 0 && error != ENOENT)
2800 		goto done;
2801 #endif
2802 #ifdef INET6
2803 	error = vfs_setopt_part(opts, JAIL_PARAM_IP6_ADDR,
2804 	    pr->pr_addrs[PR_INET6]->pr_ip,
2805 	    pr->pr_addrs[PR_INET6] ? pr->pr_addrs[PR_INET6]->ips *
2806 	    pr_families[PR_INET6].size : 0 );
2807 	if (error != 0 && error != ENOENT)
2808 		goto done;
2809 #endif
2810 	error = vfs_setopt(opts, JAIL_PARAM_SECURELEVEL, &pr->pr_securelevel,
2811 	    sizeof(pr->pr_securelevel));
2812 	if (error != 0 && error != ENOENT)
2813 		goto done;
2814 	error = vfs_setopt(opts, JAIL_PARAM_CHILDREN_CUR, &pr->pr_childcount,
2815 	    sizeof(pr->pr_childcount));
2816 	if (error != 0 && error != ENOENT)
2817 		goto done;
2818 	error = vfs_setopt(opts, JAIL_PARAM_CHILDREN_MAX, &pr->pr_childmax,
2819 	    sizeof(pr->pr_childmax));
2820 	if (error != 0 && error != ENOENT)
2821 		goto done;
2822 	error = vfs_setopts(opts, JAIL_PARAM_HOST_HOSTNAME, pr->pr_hostname);
2823 	if (error != 0 && error != ENOENT)
2824 		goto done;
2825 	error = vfs_setopts(opts, JAIL_PARAM_HOST_DOMAINNAME, pr->pr_domainname);
2826 	if (error != 0 && error != ENOENT)
2827 		goto done;
2828 	error = vfs_setopts(opts, JAIL_PARAM_HOST_HOSTUUID, pr->pr_hostuuid);
2829 	if (error != 0 && error != ENOENT)
2830 		goto done;
2831 #ifdef COMPAT_FREEBSD32
2832 	if (SV_PROC_FLAG(td->td_proc, SV_ILP32)) {
2833 		uint32_t hid32 = pr->pr_hostid;
2834 
2835 		error = vfs_setopt(opts, JAIL_PARAM_HOST_HOSTID, &hid32, sizeof(hid32));
2836 	} else
2837 #endif
2838 	error = vfs_setopt(opts, JAIL_PARAM_HOST_HOSTID, &pr->pr_hostid,
2839 	    sizeof(pr->pr_hostid));
2840 	if (error != 0 && error != ENOENT)
2841 		goto done;
2842 	error = vfs_setopt(opts, JAIL_PARAM_ENFORCE_STATFS, &pr->pr_enforce_statfs,
2843 	    sizeof(pr->pr_enforce_statfs));
2844 	if (error != 0 && error != ENOENT)
2845 		goto done;
2846 	error = vfs_setopt(opts, JAIL_PARAM_DEVFS_RULESET, &pr->pr_devfs_rsnum,
2847 	    sizeof(pr->pr_devfs_rsnum));
2848 	if (error != 0 && error != ENOENT)
2849 		goto done;
2850 	for (bf = pr_flag_bool;
2851 	     bf < pr_flag_bool + nitems(pr_flag_bool);
2852 	     bf++) {
2853 		i = (pr->pr_flags & bf->flag) ? 1 : 0;
2854 		error = vfs_setopt(opts, bf->name, &i, sizeof(i));
2855 		if (error != 0 && error != ENOENT)
2856 			goto done;
2857 		i = !i;
2858 		error = vfs_setopt(opts, bf->noname, &i, sizeof(i));
2859 		if (error != 0 && error != ENOENT)
2860 			goto done;
2861 	}
2862 	for (jsf = pr_flag_jailsys;
2863 	     jsf < pr_flag_jailsys + nitems(pr_flag_jailsys);
2864 	     jsf++) {
2865 		f = pr->pr_flags & (jsf->disable | jsf->new);
2866 		i = (f != 0 && f == jsf->disable) ? JAIL_SYS_DISABLE
2867 		    : (f == jsf->new) ? JAIL_SYS_NEW
2868 		    : JAIL_SYS_INHERIT;
2869 		error = vfs_setopt(opts, jsf->name, &i, sizeof(i));
2870 		if (error != 0 && error != ENOENT)
2871 			goto done;
2872 	}
2873 	for (bf = pr_flag_allow;
2874 	     bf < pr_flag_allow + nitems(pr_flag_allow) &&
2875 		atomic_load_int(&bf->flag) != 0;
2876 	     bf++) {
2877 		i = (pr->pr_allow & bf->flag) ? 1 : 0;
2878 		error = vfs_setopt(opts, bf->name, &i, sizeof(i));
2879 		if (error != 0 && error != ENOENT)
2880 			goto done;
2881 		i = !i;
2882 		error = vfs_setopt(opts, bf->noname, &i, sizeof(i));
2883 		if (error != 0 && error != ENOENT)
2884 			goto done;
2885 	}
2886 	i = !prison_isalive(pr);
2887 	error = vfs_setopt(opts, JAIL_PARAM_DYING, &i, sizeof(i));
2888 	if (error != 0 && error != ENOENT)
2889 		goto done;
2890 	i = !i;
2891 	error = vfs_setopt(opts, JAIL_PARAM_NODYING, &i, sizeof(i));
2892 	if (error != 0 && error != ENOENT)
2893 		goto done;
2894 	error = vfs_setopt(opts, JAIL_PARAM_OSRELDATE, &pr->pr_osreldate,
2895 	    sizeof(pr->pr_osreldate));
2896 	if (error != 0 && error != ENOENT)
2897 		goto done;
2898 	error = vfs_setopts(opts, JAIL_PARAM_OSRELEASE, pr->pr_osrelease);
2899 	if (error != 0 && error != ENOENT)
2900 		goto done;
2901 
2902 #ifdef MAC
2903 	/*
2904 	 * We get the MAC label last because we'll let the MAC framework drop
2905 	 * pr_mtx to externalize the label.
2906 	 */
2907 	error = mac_get_prison(td, pr, opts);
2908 	mtx_assert(&pr->pr_mtx, MA_NOTOWNED);
2909 	drflags &= ~PD_LOCKED;
2910 	if (error != 0 && error != ENOENT)
2911 		goto done;
2912 #else
2913 	mtx_unlock(&pr->pr_mtx);
2914 	drflags &= ~PD_LOCKED;
2915 #endif
2916 
2917 	/* Get the module parameters. */
2918 	error = osd_jail_call(pr, PR_METHOD_GET, opts);
2919 	if (error)
2920 		goto done;
2921 	prison_deref(pr, drflags);
2922 	pr = NULL;
2923 	drflags = 0;
2924 
2925 	/* By now, all parameters should have been noted. */
2926 	TAILQ_FOREACH(opt, opts, link) {
2927 		if (!opt->seen &&
2928 		    (strstr(opt->name, JAIL_META_PRIVATE ".") == opt->name ||
2929 		    strstr(opt->name, JAIL_META_SHARED ".") == opt->name)) {
2930 			/* Communicate back a missing key. */
2931 			free(opt->value, M_MOUNT);
2932 			opt->value = NULL;
2933 			opt->len = 0;
2934 			continue;
2935 		}
2936 		if (!opt->seen && strcmp(opt->name, "errmsg")) {
2937 			error = EINVAL;
2938 			vfs_opterror(opts, "unknown parameter: %s", opt->name);
2939 			goto done;
2940 		}
2941 	}
2942 
2943 	/* Write the fetched parameters back to userspace. */
2944 	error = 0;
2945 	TAILQ_FOREACH(opt, opts, link) {
2946 		if (opt->pos >= 0 && opt->pos != errmsg_pos) {
2947 			pos = 2 * opt->pos + 1;
2948 			optuio->uio_iov[pos].iov_len = opt->len;
2949 			if (opt->value != NULL) {
2950 				if (optuio->uio_segflg == UIO_SYSSPACE) {
2951 					bcopy(opt->value,
2952 					    optuio->uio_iov[pos].iov_base,
2953 					    opt->len);
2954 				} else {
2955 					error = copyout(opt->value,
2956 					    optuio->uio_iov[pos].iov_base,
2957 					    opt->len);
2958 					if (error)
2959 						break;
2960 				}
2961 			}
2962 		}
2963 	}
2964 
2965  done:
2966 	/* Release any temporary prison holds and/or locks. */
2967 	if (pr != NULL)
2968 		prison_deref(pr, drflags);
2969 	else if (drflags & PD_LIST_SLOCKED)
2970 		sx_sunlock(&allprison_lock);
2971 	else if (drflags & PD_LIST_XLOCKED)
2972 		sx_xunlock(&allprison_lock);
2973 	/* Clean up other resources. */
2974 	if (jfp_out != NULL)
2975 		(void)fdrop(jfp_out, td);
2976 	if (error && jfd_out >= 0)
2977 		(void)kern_close(td, jfd_out);
2978 	if (error && errmsg_pos >= 0) {
2979 		/* Write the error message back to userspace. */
2980 		vfs_getopt(opts, JAIL_PARAM_ERRMSG, (void **)&errmsg, &errmsg_len);
2981 		errmsg_pos = 2 * errmsg_pos + 1;
2982 		if (errmsg_len > 0) {
2983 			if (optuio->uio_segflg == UIO_SYSSPACE)
2984 				bcopy(errmsg,
2985 				    optuio->uio_iov[errmsg_pos].iov_base,
2986 				    errmsg_len);
2987 			else
2988 				(void)copyout(errmsg,
2989 				    optuio->uio_iov[errmsg_pos].iov_base,
2990 				    errmsg_len);
2991 		}
2992 	}
2993 	vfs_freeopts(opts);
2994 	prison_free(mypr);
2995 	return (error);
2996 }
2997 
2998 /*
2999  * struct jail_remove_args {
3000  *	int jid;
3001  * };
3002  */
3003 int
3004 sys_jail_remove(struct thread *td, struct jail_remove_args *uap)
3005 {
3006 	struct prison *pr;
3007 	int error;
3008 
3009 	error = priv_check(td, PRIV_JAIL_REMOVE);
3010 	if (error)
3011 		return (error);
3012 
3013 	sx_xlock(&allprison_lock);
3014 	pr = prison_find_child(td->td_ucred->cr_prison, uap->jid);
3015 	if (pr == NULL) {
3016 		sx_xunlock(&allprison_lock);
3017 		return (EINVAL);
3018 	}
3019 #ifdef MAC
3020 	error = mac_prison_check_remove(td->td_ucred, pr);
3021 	if (error != 0) {
3022 		mtx_unlock(&pr->pr_mtx);
3023 		sx_xunlock(&allprison_lock);
3024 		return (error);
3025 	}
3026 #endif
3027 	prison_hold(pr);
3028 	prison_remove(pr);
3029 	return (0);
3030 }
3031 
3032 /*
3033  * struct jail_remove_jd_args {
3034  *	int fd;
3035  * };
3036  */
3037 int
3038 sys_jail_remove_jd(struct thread *td, struct jail_remove_jd_args *uap)
3039 {
3040 	struct prison *pr;
3041 	struct ucred *jdcred;
3042 	int error;
3043 
3044 	error = jaildesc_find(td, uap->fd, &pr, &jdcred);
3045 	if (error)
3046 		return (error);
3047 	error = priv_check_cred(jdcred, PRIV_JAIL_REMOVE);
3048 	crfree(jdcred);
3049 #ifdef MAC
3050 	if (error == 0)
3051 		error = mac_prison_check_remove(td->td_ucred, pr);
3052 #endif
3053 	if (error) {
3054 		prison_free(pr);
3055 		return (error);
3056 	}
3057 	sx_xlock(&allprison_lock);
3058 	mtx_lock(&pr->pr_mtx);
3059 	prison_remove(pr);
3060 	return (0);
3061 }
3062 
3063 /*
3064  * Begin the removal process for a prison.  The allprison lock should
3065  * be held exclusively, and the prison should be both locked and held.
3066  */
3067 void
3068 prison_remove(struct prison *pr)
3069 {
3070 	sx_assert(&allprison_lock, SA_XLOCKED);
3071 	mtx_assert(&pr->pr_mtx, MA_OWNED);
3072 	prison_deref(pr, PD_KILL | PD_DEREF | PD_LOCKED | PD_LIST_XLOCKED);
3073 }
3074 
3075 /*
3076  * struct jail_attach_args {
3077  *	int jid;
3078  * };
3079  */
3080 int
3081 sys_jail_attach(struct thread *td, struct jail_attach_args *uap)
3082 {
3083 	struct prison *pr;
3084 	int drflags, error;
3085 
3086 	error = priv_check(td, PRIV_JAIL_ATTACH);
3087 	if (error)
3088 		return (error);
3089 	/* Only let a single thread in the process try to attach at a time. */
3090 	error = prison_attach_thread_single(td);
3091 	if (error != 0)
3092 		return (error);
3093 
3094 	sx_slock(&allprison_lock);
3095 	drflags = PD_LIST_SLOCKED;
3096 	pr = prison_find_child(td->td_ucred->cr_prison, uap->jid);
3097 	if (pr == NULL) {
3098 		error = EINVAL;
3099 		goto done;
3100 	}
3101 	drflags |= PD_LOCKED;
3102 
3103 #ifdef MAC
3104 	error = mac_prison_check_attach(td->td_ucred, pr);
3105 	if (error != 0)
3106 		goto done;
3107 #endif
3108 
3109 	/* Do not allow a process to attach to a prison that is not alive. */
3110 	if (!prison_isalive(pr)) {
3111 		error = EINVAL;
3112 		goto done;
3113 	}
3114 
3115 	error = do_jail_attach(td, pr, &drflags);
3116 
3117  done:
3118 	prison_deref(pr, drflags);
3119 	prison_attach_thread_single_end(td);
3120 	return (error);
3121 }
3122 
3123 /*
3124  * struct jail_attach_jd_args {
3125  *	int fd;
3126  * };
3127  */
3128 int
3129 sys_jail_attach_jd(struct thread *td, struct jail_attach_jd_args *uap)
3130 {
3131 	struct prison *pr;
3132 	struct ucred *jdcred;
3133 	int drflags, error;
3134 
3135 	/* Only let a single thread in the process try to attach at a time. */
3136 	error = prison_attach_thread_single(td);
3137 	if (error != 0)
3138 		return (error);
3139 
3140 	sx_slock(&allprison_lock);
3141 	drflags = PD_LIST_SLOCKED;
3142 	pr = NULL;
3143 	error = jaildesc_find(td, uap->fd, &pr, &jdcred);
3144 	if (error)
3145 		goto done;
3146 	drflags |= PD_DEREF;
3147 	error = priv_check_cred(jdcred, PRIV_JAIL_ATTACH);
3148 #ifdef MAC
3149 	if (error == 0)
3150 		error = mac_prison_check_attach(td->td_ucred, pr);
3151 #endif
3152 	crfree(jdcred);
3153 	if (error)
3154 		goto done;
3155 
3156 	/* Do not allow a process to attach to a prison that is not alive. */
3157 	if (!prison_isalive(pr)) {
3158 		error = EINVAL;
3159 		goto done;
3160 	}
3161 
3162 	error = do_jail_attach(td, pr, &drflags);
3163 
3164  done:
3165 	prison_deref(pr, drflags);
3166 	prison_attach_thread_single_end(td);
3167 	return (error);
3168 }
3169 
3170 /*
3171  * Attach the current process to a prison.  On entry, the allprison
3172  * lock should be at least shared.  On exit, both it and the prison
3173  * itself will be unlocked, which will be refelected in *drflagsp.
3174  */
3175 static int
3176 do_jail_attach(struct thread *td, struct prison *pr, int *drflagsp)
3177 {
3178 	struct proc *p;
3179 	struct ucred *newcred, *oldcred;
3180 	int drflags, error;
3181 
3182 	sx_assert(&allprison_lock, SX_LOCKED);
3183 	KASSERT(prison_isvalid(pr), ("Attaching to invalid prison %p", pr));
3184 	/*
3185 	 * Note the caller's locking state, but gain and track our own
3186 	 * references.  The caller will see that locks have been
3187 	 * dropped (which isn't true now, but will be after OSD calls).
3188 	 */
3189 	prison_hold(pr);
3190 	refcount_acquire(&pr->pr_uref);
3191 	drflags = PD_DEREF | PD_DEUREF | (*drflagsp & PD_LOCK_FLAGS);
3192 	*drflagsp &= PD_OP_FLAGS;
3193 
3194 	/* Let modules do whatever they need to prepare for attaching. */
3195 	if (drflags & PD_LOCKED) {
3196 		mtx_unlock(&pr->pr_mtx);
3197 		drflags &= ~PD_LOCKED;
3198 	}
3199 	error = osd_jail_call(pr, PR_METHOD_ATTACH, td);
3200 	if (error)
3201 		goto e_revert_osd;
3202 	sx_unlock(&allprison_lock);
3203 	drflags &= ~(PD_LIST_SLOCKED | PD_LIST_XLOCKED);
3204 
3205 	/*
3206 	 * Reparent the newly attached process to this jail.
3207 	 */
3208 	p = td->td_proc;
3209 	error = cpuset_setproc_update_set(p, pr->pr_cpuset);
3210 	if (error)
3211 		goto e_revert_osd;
3212 
3213 	vn_lock(pr->pr_root, LK_EXCLUSIVE | LK_RETRY);
3214 	if ((error = change_dir(pr->pr_root, td)) != 0)
3215 		goto e_unlock;
3216 #ifdef MAC
3217 	if ((error = mac_vnode_check_chroot(td->td_ucred, pr->pr_root)))
3218 		goto e_unlock;
3219 #endif
3220 	VOP_UNLOCK(pr->pr_root);
3221 	if ((error = pwd_chroot_chdir(td, pr->pr_root)))
3222 		goto e_revert_osd;
3223 
3224 	newcred = crget();
3225 	PROC_LOCK(p);
3226 	oldcred = crcopysafe(p, newcred);
3227 	newcred->cr_prison = pr;
3228 #ifdef RACCT
3229 	racct_proc_ucred_changed(p, oldcred, newcred);
3230 #endif
3231 #ifdef RCTL
3232 	crhold(newcred);
3233 #endif
3234 	/*
3235 	 * Takes over 'newcred''s reference, so 'newcred' must not be used
3236 	 * besides this point except on RCTL where we took an additional
3237 	 * reference above.
3238 	 */
3239 	proc_set_cred(p, newcred);
3240 	setsugid(p);
3241 	PROC_UNLOCK(p);
3242 #ifdef RCTL
3243 	rctl_proc_ucred_changed(p, newcred);
3244 	crfree(newcred);
3245 #endif
3246 	prison_proc_relink(oldcred->cr_prison, pr, p);
3247 	prison_deref(oldcred->cr_prison, drflags);
3248 	crfree(oldcred);
3249 	prison_knote(pr, NOTE_JAIL_ATTACH | td->td_proc->p_pid);
3250 #ifdef MAC
3251 	/*
3252 	 * Note that mac_prison_attached() assumes that it's called in a
3253 	 * sleepable context.
3254 	 */
3255 	mac_prison_attached(td->td_ucred, pr, td->td_proc);
3256 #endif
3257 
3258 	/*
3259 	 * If the prison was killed while changing credentials, die along
3260 	 * with it.
3261 	 */
3262 	if (!prison_isalive(pr)) {
3263 		PROC_LOCK(p);
3264 		kern_psignal(p, SIGKILL);
3265 		PROC_UNLOCK(p);
3266 	}
3267 
3268 	return (0);
3269 
3270  e_unlock:
3271 	VOP_UNLOCK(pr->pr_root);
3272  e_revert_osd:
3273 	/* Tell modules this process is still in its old jail after all. */
3274 	if (!(drflags & (PD_LIST_SLOCKED | PD_LIST_XLOCKED))) {
3275 		sx_slock(&allprison_lock);
3276 		drflags |= PD_LIST_SLOCKED;
3277 	}
3278 	(void)osd_jail_call(td->td_ucred->cr_prison, PR_METHOD_ATTACH, td);
3279 	prison_deref(pr, drflags);
3280 	return (error);
3281 }
3282 
3283 /*
3284  * Only one thread in a process should try to attach to a jail, or
3285  * they might end up with a process root from one prison, but attached
3286  * to the jail of another.  Enforce this by making the process run in
3287  * single-threaded mode for the duration of the system call, which
3288  * also prevents other related calls such as chroot.
3289  */
3290 static int
3291 prison_attach_thread_single(struct thread *td)
3292 {
3293 	struct proc *p;
3294 	int error;
3295 
3296 	error = 0;
3297 	p = td->td_proc;
3298 	if ((atomic_load_int(&p->p_flag) & P_HADTHREADS) != 0) {
3299 		PROC_LOCK(p);
3300 		if (thread_single(p, SINGLE_BOUNDARY))
3301 			error = ERESTART;
3302 		PROC_UNLOCK(p);
3303 	}
3304 	return (error);
3305 }
3306 
3307 static void
3308 prison_attach_thread_single_end(struct thread *td)
3309 {
3310 	struct proc *p;
3311 
3312 	p = td->td_proc;
3313 	if ((atomic_load_int(&p->p_flag) & P_HADTHREADS) != 0) {
3314 		PROC_LOCK(p);
3315 		thread_single_end(p, SINGLE_BOUNDARY);
3316 		PROC_UNLOCK(p);
3317 	}
3318 }
3319 
3320 /*
3321  * Returns a locked prison instance, or NULL on failure.
3322  */
3323 struct prison *
3324 prison_find(int prid)
3325 {
3326 	struct prison *pr;
3327 
3328 	sx_assert(&allprison_lock, SX_LOCKED);
3329 	TAILQ_FOREACH(pr, &allprison, pr_list) {
3330 		if (pr->pr_id < prid)
3331 			continue;
3332 		if (pr->pr_id > prid)
3333 			break;
3334 		KASSERT(prison_isvalid(pr), ("Found invalid prison %p", pr));
3335 		mtx_lock(&pr->pr_mtx);
3336 		return (pr);
3337 	}
3338 	return (NULL);
3339 }
3340 
3341 /*
3342  * Find a prison that is a descendant of mypr.  Returns a locked prison or NULL.
3343  */
3344 struct prison *
3345 prison_find_child(struct prison *mypr, int prid)
3346 {
3347 	struct prison *pr;
3348 	int descend;
3349 
3350 	sx_assert(&allprison_lock, SX_LOCKED);
3351 	FOREACH_PRISON_DESCENDANT(mypr, pr, descend) {
3352 		if (pr->pr_id == prid) {
3353 			KASSERT(prison_isvalid(pr),
3354 			    ("Found invalid prison %p", pr));
3355 			mtx_lock(&pr->pr_mtx);
3356 			return (pr);
3357 		}
3358 	}
3359 	return (NULL);
3360 }
3361 
3362 /*
3363  * Look for the name relative to mypr.  Returns a locked prison or NULL.
3364  */
3365 struct prison *
3366 prison_find_name(struct prison *mypr, const char *name)
3367 {
3368 	struct prison *pr, *deadpr;
3369 	size_t mylen;
3370 	int descend;
3371 
3372 	sx_assert(&allprison_lock, SX_LOCKED);
3373 	mylen = (mypr == &prison0) ? 0 : strlen(mypr->pr_name) + 1;
3374 	deadpr = NULL;
3375 	FOREACH_PRISON_DESCENDANT(mypr, pr, descend) {
3376 		if (!strcmp(pr->pr_name + mylen, name)) {
3377 			KASSERT(prison_isvalid(pr),
3378 			    ("Found invalid prison %p", pr));
3379 			if (prison_isalive(pr)) {
3380 				mtx_lock(&pr->pr_mtx);
3381 				return (pr);
3382 			}
3383 			deadpr = pr;
3384 		}
3385 	}
3386 	/* There was no valid prison - perhaps there was a dying one. */
3387 	if (deadpr != NULL)
3388 		mtx_lock(&deadpr->pr_mtx);
3389 	return (deadpr);
3390 }
3391 
3392 /*
3393  * See if a prison has the specific flag set.  The prison should be locked,
3394  * unless checking for flags that are only set at jail creation (such as
3395  * PR_IP4 and PR_IP6), or only the single bit is examined, without regard
3396  * to any other prison data.
3397  */
3398 bool
3399 prison_flag(struct ucred *cred, unsigned flag)
3400 {
3401 
3402 	return ((cred->cr_prison->pr_flags & flag) != 0);
3403 }
3404 
3405 /*
3406  * See if a prison has the specific allow flag set.
3407  * The prison *should* be locked, or only a single bit is examined, without
3408  * regard to any other prison data.
3409  */
3410 bool
3411 prison_allow(struct ucred *cred, unsigned flag)
3412 {
3413 
3414 	return ((cred->cr_prison->pr_allow & flag) != 0);
3415 }
3416 
3417 /*
3418  * Hold a prison reference, by incrementing pr_ref.  It is generally
3419  * an error to hold a prison that does not already have a reference.
3420  * A prison record will remain valid as long as it has at least one
3421  * reference, and will not be removed as long as either the prison
3422  * mutex or the allprison lock is held (allprison_lock may be shared).
3423  */
3424 void
3425 prison_hold_locked(struct prison *pr)
3426 {
3427 
3428 	/* Locking is no longer required. */
3429 	prison_hold(pr);
3430 }
3431 
3432 void
3433 prison_hold(struct prison *pr)
3434 {
3435 #ifdef INVARIANTS
3436 	int was_valid = refcount_acquire_if_not_zero(&pr->pr_ref);
3437 
3438 	KASSERT(was_valid,
3439 	    ("Trying to hold dead prison %p (jid=%d).", pr, pr->pr_id));
3440 #else
3441 	refcount_acquire(&pr->pr_ref);
3442 #endif
3443 }
3444 
3445 /*
3446  * Remove a prison reference.  If that was the last reference, the
3447  * prison will be removed (at a later time).
3448  */
3449 void
3450 prison_free_locked(struct prison *pr)
3451 {
3452 
3453 	mtx_assert(&pr->pr_mtx, MA_OWNED);
3454 	/*
3455 	 * Locking is no longer required, but unlock because the caller
3456 	 * expects it.
3457 	 */
3458 	mtx_unlock(&pr->pr_mtx);
3459 	prison_free(pr);
3460 }
3461 
3462 void
3463 prison_free(struct prison *pr)
3464 {
3465 
3466 	KASSERT(refcount_load(&pr->pr_ref) > 0,
3467 	    ("Trying to free dead prison %p (jid=%d).",
3468 	     pr, pr->pr_id));
3469 	if (!refcount_release_if_not_last(&pr->pr_ref)) {
3470 		/*
3471 		 * Don't remove the last reference in this context,
3472 		 * in case there are locks held.
3473 		 */
3474 		taskqueue_enqueue(taskqueue_jail_remove, &pr->pr_task);
3475 	}
3476 }
3477 
3478 static void
3479 prison_free_not_last(struct prison *pr)
3480 {
3481 #ifdef INVARIANTS
3482 	int lastref;
3483 
3484 	KASSERT(refcount_load(&pr->pr_ref) > 0,
3485 	    ("Trying to free dead prison %p (jid=%d).",
3486 	     pr, pr->pr_id));
3487 	lastref = refcount_release(&pr->pr_ref);
3488 	KASSERT(!lastref,
3489 	    ("prison_free_not_last freed last ref on prison %p (jid=%d).",
3490 	     pr, pr->pr_id));
3491 #else
3492 	refcount_release(&pr->pr_ref);
3493 #endif
3494 }
3495 
3496 /*
3497  * Hold a prison for user visibility, by incrementing pr_uref.
3498  * It is generally an error to hold a prison that isn't already
3499  * user-visible, except through the jail system calls.  It is also
3500  * an error to hold an invalid prison.  A prison record will remain
3501  * alive as long as it has at least one user reference, and will not
3502  * be set to the dying state until the prison mutex and allprison_lock
3503  * are both freed.
3504  */
3505 void
3506 prison_proc_hold(struct prison *pr)
3507 {
3508 #ifdef INVARIANTS
3509 	int was_alive = refcount_acquire_if_not_zero(&pr->pr_uref);
3510 
3511 	KASSERT(was_alive,
3512 	    ("Cannot add a process to a non-alive prison (jid=%d)", pr->pr_id));
3513 #else
3514 	refcount_acquire(&pr->pr_uref);
3515 #endif
3516 }
3517 
3518 /*
3519  * Remove a prison user reference.  If it was the last reference, the
3520  * prison will be considered "dying", and may be removed once all of
3521  * its references are dropped.
3522  */
3523 void
3524 prison_proc_free(struct prison *pr)
3525 {
3526 
3527 	/*
3528 	 * Locking is only required when releasing the last reference.
3529 	 * This allows assurance that a locked prison will remain alive
3530 	 * until it is unlocked.
3531 	 */
3532 	KASSERT(refcount_load(&pr->pr_uref) > 0,
3533 	    ("Trying to kill a process in a dead prison (jid=%d)", pr->pr_id));
3534 	if (!refcount_release_if_not_last(&pr->pr_uref)) {
3535 		/*
3536 		 * Don't remove the last user reference in this context,
3537 		 * which is expected to be a process that is not only locked,
3538 		 * but also half dead.  Add a reference so any calls to
3539 		 * prison_free() won't re-submit the task.
3540 		 */
3541 		prison_hold(pr);
3542 		mtx_lock(&pr->pr_mtx);
3543 		KASSERT(!(pr->pr_flags & PR_COMPLETE_PROC),
3544 		    ("Redundant last reference in prison_proc_free (jid=%d)",
3545 		     pr->pr_id));
3546 		pr->pr_flags |= PR_COMPLETE_PROC;
3547 		mtx_unlock(&pr->pr_mtx);
3548 		taskqueue_enqueue(taskqueue_jail_remove, &pr->pr_task);
3549 	}
3550 }
3551 
3552 static void
3553 prison_proc_free_not_last(struct prison *pr)
3554 {
3555 #ifdef INVARIANTS
3556 	int lastref;
3557 
3558 	KASSERT(refcount_load(&pr->pr_uref) > 0,
3559 	    ("Trying to free dead prison %p (jid=%d).",
3560 	     pr, pr->pr_id));
3561 	lastref = refcount_release(&pr->pr_uref);
3562 	KASSERT(!lastref,
3563 	    ("prison_proc_free_not_last freed last uref on prison %p (jid=%d).",
3564 	     pr, pr->pr_id));
3565 #else
3566 	refcount_release(&pr->pr_uref);
3567 #endif
3568 }
3569 
3570 void
3571 prison_proc_link(struct prison *pr, struct proc *p)
3572 {
3573 
3574 	sx_assert(&allproc_lock, SA_XLOCKED);
3575 	LIST_INSERT_HEAD(&pr->pr_proclist, p, p_jaillist);
3576 }
3577 
3578 void
3579 prison_proc_unlink(struct prison *pr, struct proc *p)
3580 {
3581 
3582 	sx_assert(&allproc_lock, SA_XLOCKED);
3583 	LIST_REMOVE(p, p_jaillist);
3584 }
3585 
3586 static void
3587 prison_proc_relink(struct prison *opr, struct prison *npr, struct proc *p)
3588 {
3589 
3590 	sx_xlock(&allproc_lock);
3591 	prison_proc_unlink(opr, p);
3592 	prison_proc_link(npr, p);
3593 	sx_xunlock(&allproc_lock);
3594 }
3595 
3596 /*
3597  * Complete a call to either prison_free or prison_proc_free.
3598  */
3599 static void
3600 prison_complete(void *context, int pending)
3601 {
3602 	struct prison *pr = context;
3603 	int drflags;
3604 
3605 	/*
3606 	 * This could be called to release the last reference, or the last
3607 	 * user reference (plus the reference held in prison_proc_free).
3608 	 */
3609 	drflags = prison_lock_xlock(pr, PD_DEREF);
3610 	if (pr->pr_flags & PR_COMPLETE_PROC) {
3611 		pr->pr_flags &= ~PR_COMPLETE_PROC;
3612 		drflags |= PD_DEUREF;
3613 	}
3614 	prison_deref(pr, drflags);
3615 }
3616 
3617 static void
3618 prison_kill_processes_cb(struct proc *p, void *arg __unused)
3619 {
3620 
3621 	kern_psignal(p, SIGKILL);
3622 }
3623 
3624 /*
3625  * Note the iteration does not guarantee acting on all processes.
3626  * Most notably there may be fork or jail_attach in progress.
3627  */
3628 void
3629 prison_proc_iterate(struct prison *pr, void (*cb)(struct proc *, void *),
3630     void *cbarg)
3631 {
3632 	struct prison *ppr;
3633 	struct proc *p;
3634 
3635 	if (atomic_load_int(&pr->pr_childcount) == 0) {
3636 		sx_slock(&allproc_lock);
3637 		LIST_FOREACH(p, &pr->pr_proclist, p_jaillist) {
3638 			if (p->p_state == PRS_NEW)
3639 				continue;
3640 			PROC_LOCK(p);
3641 			cb(p, cbarg);
3642 			PROC_UNLOCK(p);
3643 		}
3644 		sx_sunlock(&allproc_lock);
3645 		if (atomic_load_int(&pr->pr_childcount) == 0)
3646 			return;
3647 		/*
3648 		 * Some jails popped up during the iteration, fall through to a
3649 		 * system-wide search.
3650 		 */
3651 	}
3652 
3653 	sx_slock(&allproc_lock);
3654 	FOREACH_PROC_IN_SYSTEM(p) {
3655 		PROC_LOCK(p);
3656 		if (p->p_state != PRS_NEW && p->p_ucred != NULL) {
3657 			for (ppr = p->p_ucred->cr_prison; ppr != NULL;
3658 			    ppr = ppr->pr_parent) {
3659 				if (ppr == pr) {
3660 					cb(p, cbarg);
3661 					break;
3662 				}
3663 			}
3664 		}
3665 		PROC_UNLOCK(p);
3666 	}
3667 	sx_sunlock(&allproc_lock);
3668 }
3669 
3670 /*
3671  * Remove a prison reference and/or user reference (usually).
3672  * This assumes context that allows sleeping (for allprison_lock),
3673  * with no non-sleeping locks held, except perhaps the prison itself.
3674  * If there are no more references, release and delist the prison.
3675  * On completion, the prison lock and the allprison lock are both
3676  * unlocked.
3677  */
3678 static void
3679 prison_deref(struct prison *pr, int flags)
3680 {
3681 	struct prisonlist freeprison;
3682 	struct prison *killpr, *rpr, *ppr, *tpr;
3683 
3684 	killpr = NULL;
3685 	TAILQ_INIT(&freeprison);
3686 	/*
3687 	 * Release this prison as requested, which may cause its parent
3688 	 * to be released, and then maybe its grandparent, etc.
3689 	 */
3690 	for (;;) {
3691 		if (flags & PD_KILL) {
3692 			/* Kill the prison and its descendents. */
3693 			KASSERT(pr != &prison0,
3694 			    ("prison_deref trying to kill prison0"));
3695 			if (!prison_isalive(pr)) {
3696 				/* Silently ignore already-dying prisons. */
3697 				flags &= ~PD_KILL;
3698 			} else {
3699 				if (!(flags & PD_DEREF)) {
3700 					prison_hold(pr);
3701 					flags |= PD_DEREF;
3702 				}
3703 				flags = prison_lock_xlock(pr, flags);
3704 				prison_deref_kill(pr, &freeprison);
3705 			}
3706 		}
3707 		if (flags & PD_DEUREF) {
3708 			/* Drop a user reference. */
3709 			KASSERT(refcount_load(&pr->pr_uref) > 0,
3710 			    ("prison_deref PD_DEUREF on a dead prison (jid=%d)",
3711 			     pr->pr_id));
3712 			if (!refcount_release_if_not_last(&pr->pr_uref)) {
3713 				if (!(flags & PD_DEREF)) {
3714 					prison_hold(pr);
3715 					flags |= PD_DEREF;
3716 				}
3717 				flags = prison_lock_xlock(pr, flags);
3718 				if (refcount_release(&pr->pr_uref) &&
3719 				    pr->pr_state == PRISON_STATE_ALIVE) {
3720 					/*
3721 					 * When the last user references goes,
3722 					 * this becomes a dying prison.
3723 					 */
3724 					KASSERT(
3725 					    refcount_load(&prison0.pr_uref) > 0,
3726 					    ("prison0 pr_uref=0"));
3727 					pr->pr_state = PRISON_STATE_DYING;
3728 					prison_cleanup_locked(pr);
3729 					mtx_unlock(&pr->pr_mtx);
3730 					flags &= ~PD_LOCKED;
3731 					prison_cleanup_unlocked(pr);
3732 				}
3733 			}
3734 		}
3735 		if (flags & PD_KILL) {
3736 			/*
3737 			 * Any remaining user references are probably processes
3738 			 * that need to be killed, either in this prison or its
3739 			 * descendants.
3740 			 */
3741 			if (refcount_load(&pr->pr_uref) > 0)
3742 				killpr = pr;
3743 			/* Make sure the parent prison doesn't get killed. */
3744 			flags &= ~PD_KILL;
3745 		}
3746 		if (flags & PD_DEREF) {
3747 			/* Drop a reference. */
3748 			KASSERT(refcount_load(&pr->pr_ref) > 0,
3749 			    ("prison_deref PD_DEREF on a dead prison (jid=%d)",
3750 			     pr->pr_id));
3751 			if (!refcount_release_if_not_last(&pr->pr_ref)) {
3752 				flags = prison_lock_xlock(pr, flags);
3753 				if (refcount_release(&pr->pr_ref)) {
3754 					/*
3755 					 * When the last reference goes,
3756 					 * unlink the prison and set it aside.
3757 					 */
3758 					KASSERT(
3759 					    refcount_load(&pr->pr_uref) == 0,
3760 					    ("prison_deref: last ref, "
3761 					     "but still has %d urefs (jid=%d)",
3762 					     pr->pr_uref, pr->pr_id));
3763 					KASSERT(
3764 					    refcount_load(&prison0.pr_ref) != 0,
3765 					    ("prison0 pr_ref=0"));
3766 #ifdef MAC
3767 					/*
3768 					 * The MAC framework will call into any
3769 					 * policies that want to hook
3770 					 * prison_destroy_label, so ideally we
3771 					 * call this prior to any final state
3772 					 * invalidation to be safe.
3773 					 */
3774 					mac_prison_destroy(pr);
3775 #endif
3776 					pr->pr_state = PRISON_STATE_INVALID;
3777 					TAILQ_REMOVE(&allprison, pr, pr_list);
3778 					LIST_REMOVE(pr, pr_sibling);
3779 					TAILQ_INSERT_TAIL(&freeprison, pr,
3780 					    pr_list);
3781 					for (ppr = pr->pr_parent;
3782 					     ppr != NULL;
3783 					     ppr = ppr->pr_parent)
3784 						ppr->pr_childcount--;
3785 					/*
3786 					 * Removing a prison frees references
3787 					 * from its parent.
3788 					 */
3789 					ppr = pr->pr_parent;
3790 					pr->pr_parent = NULL;
3791 					mtx_unlock(&pr->pr_mtx);
3792 
3793 					pr = ppr;
3794 					flags &= ~PD_LOCKED;
3795 					flags |= PD_DEREF | PD_DEUREF;
3796 					continue;
3797 				}
3798 			}
3799 		}
3800 		break;
3801 	}
3802 
3803 	/* Release all the prison locks. */
3804 	if (flags & PD_LOCKED)
3805 		mtx_unlock(&pr->pr_mtx);
3806 	if (flags & PD_LIST_SLOCKED)
3807 		sx_sunlock(&allprison_lock);
3808 	else if (flags & PD_LIST_XLOCKED)
3809 		sx_xunlock(&allprison_lock);
3810 
3811 	/* Kill any processes attached to a killed prison. */
3812 	if (killpr != NULL)
3813 		prison_proc_iterate(killpr, prison_kill_processes_cb, NULL);
3814 
3815 	/*
3816 	 * Finish removing any unreferenced prisons, which couldn't happen
3817 	 * while allprison_lock was held (to avoid a LOR on vrele).
3818 	 */
3819 	TAILQ_FOREACH_SAFE(rpr, &freeprison, pr_list, tpr) {
3820 #ifdef VIMAGE
3821 		if (rpr->pr_flags & PR_VNET)
3822 			vnet_destroy(rpr->pr_vnet);
3823 #endif
3824 		if (rpr->pr_root != NULL)
3825 			vrele(rpr->pr_root);
3826 		mtx_destroy(&rpr->pr_mtx);
3827 #ifdef INET
3828 		prison_ip_free(rpr->pr_addrs[PR_INET]);
3829 #endif
3830 #ifdef INET6
3831 		prison_ip_free(rpr->pr_addrs[PR_INET6]);
3832 #endif
3833 		if (rpr->pr_cpuset != NULL)
3834 			cpuset_rel(rpr->pr_cpuset);
3835 		osd_jail_exit(rpr);
3836 #ifdef RACCT
3837 		if (racct_enable)
3838 			prison_racct_detach(rpr);
3839 #endif
3840 		TAILQ_REMOVE(&freeprison, rpr, pr_list);
3841 		free(rpr, M_PRISON);
3842 	}
3843 }
3844 
3845 /*
3846  * Kill the prison and its descendants.  Mark them as dying, clear the
3847  * persist flag, and call module remove methods.
3848  */
3849 static void
3850 prison_deref_kill(struct prison *pr, struct prisonlist *freeprison)
3851 {
3852 	struct prison *cpr, *ppr, *rpr;
3853 	bool descend;
3854 
3855 	/*
3856 	 * Unlike the descendants, the target prison can be killed
3857 	 * even if it is currently dying.  This is useful for failed
3858 	 * creation in jail_set(2).
3859 	 */
3860 	KASSERT(refcount_load(&pr->pr_ref) > 0,
3861 	    ("Trying to kill dead prison %p (jid=%d).",
3862 	     pr, pr->pr_id));
3863 	refcount_acquire(&pr->pr_uref);
3864 	pr->pr_state = PRISON_STATE_DYING;
3865 	mtx_unlock(&pr->pr_mtx);
3866 
3867 	rpr = NULL;
3868 	FOREACH_PRISON_DESCENDANT_PRE_POST(pr, cpr, descend) {
3869 		if (descend) {
3870 			if (!prison_isalive(cpr)) {
3871 				descend = false;
3872 				continue;
3873 			}
3874 			prison_hold(cpr);
3875 			prison_proc_hold(cpr);
3876 			mtx_lock(&cpr->pr_mtx);
3877 			cpr->pr_state = PRISON_STATE_DYING;
3878 			cpr->pr_flags |= PR_REMOVE;
3879 			mtx_unlock(&cpr->pr_mtx);
3880 			continue;
3881 		}
3882 		if (!(cpr->pr_flags & PR_REMOVE))
3883 			continue;
3884 		prison_cleanup_unlocked(cpr);
3885 		mtx_lock(&cpr->pr_mtx);
3886 		prison_cleanup_locked(cpr);
3887 		cpr->pr_flags &= ~PR_REMOVE;
3888 		if (cpr->pr_flags & PR_PERSIST) {
3889 			cpr->pr_flags &= ~PR_PERSIST;
3890 			prison_proc_free_not_last(cpr);
3891 			prison_free_not_last(cpr);
3892 		}
3893 		(void)refcount_release(&cpr->pr_uref);
3894 		if (refcount_release(&cpr->pr_ref)) {
3895 			/*
3896 			 * When the last reference goes, unlink the prison
3897 			 * and set it aside for prison_deref() to handle.
3898 			 * Delay unlinking the sibling list to keep the loop
3899 			 * safe.
3900 			 */
3901 			if (rpr != NULL)
3902 				LIST_REMOVE(rpr, pr_sibling);
3903 			rpr = cpr;
3904 			rpr->pr_state = PRISON_STATE_INVALID;
3905 			TAILQ_REMOVE(&allprison, rpr, pr_list);
3906 			TAILQ_INSERT_TAIL(freeprison, rpr, pr_list);
3907 			/*
3908 			 * Removing a prison frees references from its parent.
3909 			 */
3910 			ppr = rpr->pr_parent;
3911 			prison_proc_free_not_last(ppr);
3912 			prison_free_not_last(ppr);
3913 			for (; ppr != NULL; ppr = ppr->pr_parent)
3914 				ppr->pr_childcount--;
3915 		}
3916 		mtx_unlock(&cpr->pr_mtx);
3917 	}
3918 	if (rpr != NULL)
3919 		LIST_REMOVE(rpr, pr_sibling);
3920 
3921 	prison_cleanup_unlocked(pr);
3922 	mtx_lock(&pr->pr_mtx);
3923 	prison_cleanup_locked(pr);
3924 	if (pr->pr_flags & PR_PERSIST) {
3925 		pr->pr_flags &= ~PR_PERSIST;
3926 		prison_proc_free_not_last(pr);
3927 		prison_free_not_last(pr);
3928 	}
3929 	(void)refcount_release(&pr->pr_uref);
3930 }
3931 
3932 /*
3933  * Given the current locking state in the flags, make sure allprison_lock
3934  * is held exclusive, and the prison is locked.  Return flags indicating
3935  * the new state.
3936  */
3937 static int
3938 prison_lock_xlock(struct prison *pr, int flags)
3939 {
3940 
3941 	if (!(flags & PD_LIST_XLOCKED)) {
3942 		/*
3943 		 * Get allprison_lock, which may be an upgrade,
3944 		 * and may require unlocking the prison.
3945 		 */
3946 		if (flags & PD_LOCKED) {
3947 			mtx_unlock(&pr->pr_mtx);
3948 			flags &= ~PD_LOCKED;
3949 		}
3950 		if (flags & PD_LIST_SLOCKED) {
3951 			if (!sx_try_upgrade(&allprison_lock)) {
3952 				sx_sunlock(&allprison_lock);
3953 				sx_xlock(&allprison_lock);
3954 			}
3955 			flags &= ~PD_LIST_SLOCKED;
3956 		} else
3957 			sx_xlock(&allprison_lock);
3958 		flags |= PD_LIST_XLOCKED;
3959 	}
3960 	if (!(flags & PD_LOCKED)) {
3961 		/* Lock the prison mutex. */
3962 		mtx_lock(&pr->pr_mtx);
3963 		flags |= PD_LOCKED;
3964 	}
3965 	return flags;
3966 }
3967 
3968 /*
3969  * Release a prison's resources when it starts dying (when the last user
3970  * reference is dropped, or when it is killed).  Two functions are called,
3971  * for work that requires a locked prison or an unlocked one.
3972  */
3973 static void
3974 prison_cleanup_locked(struct prison *pr)
3975 {
3976 	sx_assert(&allprison_lock, SA_XLOCKED);
3977 	mtx_assert(&pr->pr_mtx, MA_OWNED);
3978 	prison_knote(pr, NOTE_JAIL_REMOVE);
3979 	knlist_detach(pr->pr_klist);
3980 	jaildesc_prison_cleanup(pr);
3981 	pr->pr_klist = NULL;
3982 }
3983 
3984 static void
3985 prison_cleanup_unlocked(struct prison *pr)
3986 {
3987 	sx_assert(&allprison_lock, SA_XLOCKED);
3988 	mtx_assert(&pr->pr_mtx, MA_NOTOWNED);
3989 	vfs_exjail_delete(pr);
3990 	shm_remove_prison(pr);
3991 	(void)osd_jail_call(pr, PR_METHOD_REMOVE, NULL);
3992 }
3993 
3994 /*
3995  * Set or clear a permission bit in the pr_allow field, passing restrictions
3996  * (cleared permission) down to child jails.
3997  */
3998 void
3999 prison_set_allow(struct ucred *cred, unsigned flag, int enable)
4000 {
4001 	struct prison *pr;
4002 
4003 	pr = cred->cr_prison;
4004 	sx_slock(&allprison_lock);
4005 	mtx_lock(&pr->pr_mtx);
4006 	prison_set_allow_locked(pr, flag, enable);
4007 	mtx_unlock(&pr->pr_mtx);
4008 	sx_sunlock(&allprison_lock);
4009 }
4010 
4011 static void
4012 prison_set_allow_locked(struct prison *pr, unsigned flag, int enable)
4013 {
4014 	struct prison *cpr;
4015 	int descend;
4016 
4017 	if (enable != 0)
4018 		pr->pr_allow |= flag;
4019 	else {
4020 		pr->pr_allow &= ~flag;
4021 		FOREACH_PRISON_DESCENDANT_LOCKED(pr, cpr, descend)
4022 			cpr->pr_allow &= ~flag;
4023 	}
4024 }
4025 
4026 /*
4027  * Check if a jail supports the given address family.
4028  *
4029  * Returns 0 if not jailed or the address family is supported, EAFNOSUPPORT
4030  * if not.
4031  */
4032 int
4033 prison_check_af(struct ucred *cred, int af)
4034 {
4035 	struct prison *pr;
4036 	int error;
4037 
4038 	KASSERT(cred != NULL, ("%s: cred is NULL", __func__));
4039 
4040 	pr = cred->cr_prison;
4041 #ifdef VIMAGE
4042 	/* Prisons with their own network stack are not limited. */
4043 	if (prison_owns_vnet(pr))
4044 		return (0);
4045 #endif
4046 
4047 	error = 0;
4048 	switch (af)
4049 	{
4050 #ifdef INET
4051 	case AF_INET:
4052 		if (pr->pr_flags & PR_IP4)
4053 		{
4054 			mtx_lock(&pr->pr_mtx);
4055 			if ((pr->pr_flags & PR_IP4) &&
4056 			    pr->pr_addrs[PR_INET] == NULL)
4057 				error = EAFNOSUPPORT;
4058 			mtx_unlock(&pr->pr_mtx);
4059 		}
4060 		break;
4061 #endif
4062 #ifdef INET6
4063 	case AF_INET6:
4064 		if (pr->pr_flags & PR_IP6)
4065 		{
4066 			mtx_lock(&pr->pr_mtx);
4067 			if ((pr->pr_flags & PR_IP6) &&
4068 			    pr->pr_addrs[PR_INET6] == NULL)
4069 				error = EAFNOSUPPORT;
4070 			mtx_unlock(&pr->pr_mtx);
4071 		}
4072 		break;
4073 #endif
4074 	case AF_LOCAL:
4075 	case AF_ROUTE:
4076 	case AF_NETLINK:
4077 		break;
4078 	default:
4079 		if (!(pr->pr_allow & PR_ALLOW_SOCKET_AF))
4080 			error = EAFNOSUPPORT;
4081 	}
4082 	return (error);
4083 }
4084 
4085 /*
4086  * Check if given address belongs to the jail referenced by cred (wrapper to
4087  * prison_check_ip[46]).
4088  *
4089  * Returns 0 if jail doesn't restrict the address family or if address belongs
4090  * to jail, EADDRNOTAVAIL if the address doesn't belong, or EAFNOSUPPORT if
4091  * the jail doesn't allow the address family.  IPv4 Address passed in in NBO.
4092  */
4093 int
4094 prison_if(struct ucred *cred, const struct sockaddr *sa)
4095 {
4096 #ifdef INET
4097 	const struct sockaddr_in *sai;
4098 #endif
4099 #ifdef INET6
4100 	const struct sockaddr_in6 *sai6;
4101 #endif
4102 	int error;
4103 
4104 	KASSERT(cred != NULL, ("%s: cred is NULL", __func__));
4105 	KASSERT(sa != NULL, ("%s: sa is NULL", __func__));
4106 
4107 #ifdef VIMAGE
4108 	if (prison_owns_vnet(cred->cr_prison))
4109 		return (0);
4110 #endif
4111 
4112 	error = 0;
4113 	switch (sa->sa_family)
4114 	{
4115 #ifdef INET
4116 	case AF_INET:
4117 		sai = (const struct sockaddr_in *)sa;
4118 		error = prison_check_ip4(cred, &sai->sin_addr);
4119 		break;
4120 #endif
4121 #ifdef INET6
4122 	case AF_INET6:
4123 		sai6 = (const struct sockaddr_in6 *)sa;
4124 		error = prison_check_ip6(cred, &sai6->sin6_addr);
4125 		break;
4126 #endif
4127 	default:
4128 		if (!(cred->cr_prison->pr_allow & PR_ALLOW_SOCKET_AF))
4129 			error = EAFNOSUPPORT;
4130 	}
4131 	return (error);
4132 }
4133 
4134 /*
4135  * Return 0 if jails permit p1 to frob p2, otherwise ESRCH.
4136  */
4137 int
4138 prison_check(struct ucred *cred1, struct ucred *cred2)
4139 {
4140 
4141 	return ((cred1->cr_prison == cred2->cr_prison ||
4142 	    prison_ischild(cred1->cr_prison, cred2->cr_prison)) ? 0 : ESRCH);
4143 }
4144 
4145 /*
4146  * For mountd/nfsd to run within a prison, it must be:
4147  * - A vnet prison.
4148  * - PR_ALLOW_NFSD must be set on it.
4149  * - The root directory (pr_root) of the prison must be
4150  *   a file system mount point, so the mountd can hang
4151  *   export information on it.
4152  * - The prison's enforce_statfs cannot be 0, so that
4153  *   mountd(8) can do exports.
4154  */
4155 bool
4156 prison_check_nfsd(struct ucred *cred)
4157 {
4158 
4159 	if (jailed_without_vnet(cred))
4160 		return (false);
4161 	if (!prison_allow(cred, PR_ALLOW_NFSD))
4162 		return (false);
4163 	if ((cred->cr_prison->pr_root->v_vflag & VV_ROOT) == 0)
4164 		return (false);
4165 	if (cred->cr_prison->pr_enforce_statfs == 0)
4166 		return (false);
4167 	return (true);
4168 }
4169 
4170 /*
4171  * Return true if p2 is a child of p1, otherwise false.
4172  */
4173 bool
4174 prison_ischild(struct prison *pr1, struct prison *pr2)
4175 {
4176 
4177 	for (pr2 = pr2->pr_parent; pr2 != NULL; pr2 = pr2->pr_parent)
4178 		if (pr1 == pr2)
4179 			return (true);
4180 	return (false);
4181 }
4182 
4183 /*
4184  * Return true if the prison is currently alive.  A prison is alive if it
4185  * holds user references and it isn't being removed.
4186  */
4187 bool
4188 prison_isalive(const struct prison *pr)
4189 {
4190 
4191 	if (__predict_false(pr->pr_state != PRISON_STATE_ALIVE))
4192 		return (false);
4193 	return (true);
4194 }
4195 
4196 /*
4197  * Return true if the prison is currently valid.  A prison is valid if it has
4198  * been fully created, and is not being destroyed.  Note that dying prisons
4199  * are still considered valid.  Invalid prisons won't be found under normal
4200  * circumstances, as they're only put in that state by functions that have
4201  * an exclusive hold on allprison_lock.
4202  */
4203 bool
4204 prison_isvalid(struct prison *pr)
4205 {
4206 
4207 	if (__predict_false(pr->pr_state == PRISON_STATE_INVALID))
4208 		return (false);
4209 	if (__predict_false(refcount_load(&pr->pr_ref) == 0))
4210 		return (false);
4211 	return (true);
4212 }
4213 
4214 /*
4215  * Return true if the passed credential is in a jail and that jail does not
4216  * have its own virtual network stack, otherwise false.
4217  */
4218 bool
4219 jailed_without_vnet(struct ucred *cred)
4220 {
4221 
4222 	if (!jailed(cred))
4223 		return (false);
4224 #ifdef VIMAGE
4225 	if (prison_owns_vnet(cred->cr_prison))
4226 		return (false);
4227 #endif
4228 
4229 	return (true);
4230 }
4231 
4232 /*
4233  * Return the correct hostname (domainname, et al) for the passed credential.
4234  */
4235 void
4236 getcredhostname(struct ucred *cred, char *buf, size_t size)
4237 {
4238 	struct prison *pr;
4239 
4240 	/*
4241 	 * A NULL credential can be used to shortcut to the physical
4242 	 * system's hostname.
4243 	 */
4244 	pr = (cred != NULL) ? cred->cr_prison : &prison0;
4245 	mtx_lock(&pr->pr_mtx);
4246 	strlcpy(buf, pr->pr_hostname, size);
4247 	mtx_unlock(&pr->pr_mtx);
4248 }
4249 
4250 void
4251 getcreddomainname(struct ucred *cred, char *buf, size_t size)
4252 {
4253 
4254 	mtx_lock(&cred->cr_prison->pr_mtx);
4255 	strlcpy(buf, cred->cr_prison->pr_domainname, size);
4256 	mtx_unlock(&cred->cr_prison->pr_mtx);
4257 }
4258 
4259 void
4260 getcredhostuuid(struct ucred *cred, char *buf, size_t size)
4261 {
4262 
4263 	mtx_lock(&cred->cr_prison->pr_mtx);
4264 	strlcpy(buf, cred->cr_prison->pr_hostuuid, size);
4265 	mtx_unlock(&cred->cr_prison->pr_mtx);
4266 }
4267 
4268 void
4269 getcredhostid(struct ucred *cred, unsigned long *hostid)
4270 {
4271 
4272 	mtx_lock(&cred->cr_prison->pr_mtx);
4273 	*hostid = cred->cr_prison->pr_hostid;
4274 	mtx_unlock(&cred->cr_prison->pr_mtx);
4275 }
4276 
4277 void
4278 getjailname(struct ucred *cred, char *name, size_t len)
4279 {
4280 
4281 	mtx_lock(&cred->cr_prison->pr_mtx);
4282 	strlcpy(name, cred->cr_prison->pr_name, len);
4283 	mtx_unlock(&cred->cr_prison->pr_mtx);
4284 }
4285 
4286 #ifdef VIMAGE
4287 /*
4288  * Determine whether the prison owns its VNET.
4289  */
4290 bool
4291 prison_owns_vnet(struct prison *pr)
4292 {
4293 
4294 	/*
4295 	 * vnets cannot be added/removed after jail creation,
4296 	 * so no need to lock here.
4297 	 */
4298 	return ((pr->pr_flags & PR_VNET) != 0);
4299 }
4300 #endif
4301 
4302 /*
4303  * Determine whether the subject represented by cred can "see"
4304  * status of a mount point.
4305  * Returns: 0 for permitted, ENOENT otherwise.
4306  * XXX: This function should be called cr_canseemount() and should be
4307  *      placed in kern_prot.c.
4308  */
4309 int
4310 prison_canseemount(struct ucred *cred, struct mount *mp)
4311 {
4312 	struct prison *pr;
4313 	struct statfs *sp;
4314 	size_t len;
4315 
4316 	pr = cred->cr_prison;
4317 	if (pr->pr_enforce_statfs == 0)
4318 		return (0);
4319 	if (pr->pr_root->v_mount == mp)
4320 		return (0);
4321 	if (pr->pr_enforce_statfs == 2)
4322 		return (ENOENT);
4323 	/*
4324 	 * If jail's chroot directory is set to "/" we should be able to see
4325 	 * all mount-points from inside a jail.
4326 	 * This is ugly check, but this is the only situation when jail's
4327 	 * directory ends with '/'.
4328 	 */
4329 	if (strcmp(pr->pr_path, "/") == 0)
4330 		return (0);
4331 	len = strlen(pr->pr_path);
4332 	sp = &mp->mnt_stat;
4333 	if (strncmp(pr->pr_path, sp->f_mntonname, len) != 0)
4334 		return (ENOENT);
4335 	/*
4336 	 * Be sure that we don't have situation where jail's root directory
4337 	 * is "/some/path" and mount point is "/some/pathpath".
4338 	 */
4339 	if (sp->f_mntonname[len] != '\0' && sp->f_mntonname[len] != '/')
4340 		return (ENOENT);
4341 	return (0);
4342 }
4343 
4344 void
4345 prison_enforce_statfs(struct ucred *cred, struct mount *mp, struct statfs *sp)
4346 {
4347 	char jpath[MAXPATHLEN];
4348 	struct prison *pr;
4349 	size_t len;
4350 
4351 	pr = cred->cr_prison;
4352 	if (pr->pr_enforce_statfs == 0)
4353 		return;
4354 	if (prison_canseemount(cred, mp) != 0) {
4355 		bzero(&sp->f_fsid, sizeof(sp->f_fsid));
4356 		bzero(sp->f_mntonname, sizeof(sp->f_mntonname));
4357 		strlcpy(sp->f_mntonname, "[restricted]",
4358 		    sizeof(sp->f_mntonname));
4359 		return;
4360 	}
4361 	if (pr->pr_enforce_statfs > 1)
4362 		bzero(&sp->f_fsid, sizeof(sp->f_fsid));
4363 	if (pr->pr_root->v_mount == mp) {
4364 		/*
4365 		 * Clear current buffer data, so we are sure nothing from
4366 		 * the valid path left there.
4367 		 */
4368 		bzero(sp->f_mntonname, sizeof(sp->f_mntonname));
4369 		*sp->f_mntonname = '/';
4370 		return;
4371 	}
4372 	/*
4373 	 * If jail's chroot directory is set to "/" we should be able to see
4374 	 * all mount-points from inside a jail.
4375 	 */
4376 	if (strcmp(pr->pr_path, "/") == 0)
4377 		return;
4378 	len = strlen(pr->pr_path);
4379 	strlcpy(jpath, sp->f_mntonname + len, sizeof(jpath));
4380 	/*
4381 	 * Clear current buffer data, so we are sure nothing from
4382 	 * the valid path left there.
4383 	 */
4384 	bzero(sp->f_mntonname, sizeof(sp->f_mntonname));
4385 	if (*jpath == '\0') {
4386 		/* Should never happen. */
4387 		*sp->f_mntonname = '/';
4388 	} else {
4389 		strlcpy(sp->f_mntonname, jpath, sizeof(sp->f_mntonname));
4390 	}
4391 }
4392 
4393 /*
4394  * Check with permission for a specific privilege is granted within jail.  We
4395  * have a specific list of accepted privileges; the rest are denied.
4396  */
4397 int
4398 prison_priv_check(struct ucred *cred, int priv)
4399 {
4400 	struct prison *pr;
4401 	int error;
4402 
4403 	/*
4404 	 * Some policies have custom handlers. This routine should not be
4405 	 * called for them. See priv_check_cred().
4406 	 */
4407 	switch (priv) {
4408 	case PRIV_VFS_LOOKUP:
4409 	case PRIV_VFS_GENERATION:
4410 		KASSERT(0, ("prison_priv_check instead of a custom handler "
4411 		    "called for %d\n", priv));
4412 	}
4413 
4414 	if (!jailed(cred))
4415 		return (0);
4416 
4417 #ifdef VIMAGE
4418 	/*
4419 	 * Privileges specific to prisons with a virtual network stack.
4420 	 * There might be a duplicate entry here in case the privilege
4421 	 * is only granted conditionally in the legacy jail case.
4422 	 */
4423 	switch (priv) {
4424 		/*
4425 		 * NFS-specific privileges.
4426 		 */
4427 	case PRIV_NFS_DAEMON:
4428 	case PRIV_VFS_GETFH:
4429 	case PRIV_VFS_MOUNT_EXPORTED:
4430 		if (!prison_check_nfsd(cred))
4431 			return (EPERM);
4432 #ifdef notyet
4433 	case PRIV_NFS_LOCKD:
4434 #endif
4435 		/*
4436 		 * Network stack privileges.
4437 		 */
4438 	case PRIV_NET_BRIDGE:
4439 	case PRIV_NET_GRE:
4440 	case PRIV_NET_BPF:
4441 	case PRIV_NET_RAW:		/* Dup, cond. in legacy jail case. */
4442 	case PRIV_NET_ROUTE:
4443 	case PRIV_NET_TAP:
4444 	case PRIV_NET_SETIFMTU:
4445 	case PRIV_NET_SETIFFLAGS:
4446 	case PRIV_NET_SETIFCAP:
4447 	case PRIV_NET_SETIFDESCR:
4448 	case PRIV_NET_SETIFNAME	:
4449 	case PRIV_NET_SETIFMETRIC:
4450 	case PRIV_NET_SETIFPHYS:
4451 	case PRIV_NET_SETIFMAC:
4452 	case PRIV_NET_SETLANPCP:
4453 	case PRIV_NET_ADDMULTI:
4454 	case PRIV_NET_DELMULTI:
4455 	case PRIV_NET_HWIOCTL:
4456 	case PRIV_NET_SETLLADDR:
4457 	case PRIV_NET_ADDIFGROUP:
4458 	case PRIV_NET_DELIFGROUP:
4459 	case PRIV_NET_IFCREATE:
4460 	case PRIV_NET_IFDESTROY:
4461 	case PRIV_NET_ADDIFADDR:
4462 	case PRIV_NET_DELIFADDR:
4463 	case PRIV_NET_LAGG:
4464 	case PRIV_NET_GIF:
4465 	case PRIV_NET_SETIFVNET:
4466 	case PRIV_NET_SETIFFIB:
4467 	case PRIV_NET_OVPN:
4468 	case PRIV_NET_GENEVE:
4469 	case PRIV_NET_ME:
4470 	case PRIV_NET_WG:
4471 
4472 		/*
4473 		 * 802.11-related privileges.
4474 		 */
4475 	case PRIV_NET80211_VAP_GETKEY:
4476 	case PRIV_NET80211_VAP_MANAGE:
4477 
4478 #ifdef notyet
4479 		/*
4480 		 * ATM privileges.
4481 		 */
4482 	case PRIV_NETATM_CFG:
4483 	case PRIV_NETATM_ADD:
4484 	case PRIV_NETATM_DEL:
4485 	case PRIV_NETATM_SET:
4486 
4487 		/*
4488 		 * Bluetooth privileges.
4489 		 */
4490 	case PRIV_NETBLUETOOTH_RAW:
4491 #endif
4492 
4493 		/*
4494 		 * Netgraph and netgraph module privileges.
4495 		 */
4496 	case PRIV_NETGRAPH_CONTROL:
4497 #ifdef notyet
4498 	case PRIV_NETGRAPH_TTY:
4499 #endif
4500 
4501 		/*
4502 		 * IPv4 and IPv6 privileges.
4503 		 */
4504 	case PRIV_NETINET_IPFW:
4505 	case PRIV_NETINET_DIVERT:
4506 	case PRIV_NETINET_PF:
4507 	case PRIV_NETINET_DUMMYNET:
4508 	case PRIV_NETINET_CARP:
4509 	case PRIV_NETINET_MROUTE:
4510 	case PRIV_NETINET_RAW:
4511 	case PRIV_NETINET_ADDRCTRL6:
4512 	case PRIV_NETINET_ND6:
4513 	case PRIV_NETINET_SCOPE6:
4514 	case PRIV_NETINET_ALIFETIME6:
4515 	case PRIV_NETINET_IPSEC:
4516 	case PRIV_NETINET_BINDANY:
4517 
4518 #ifdef notyet
4519 		/*
4520 		 * NCP privileges.
4521 		 */
4522 	case PRIV_NETNCP:
4523 
4524 		/*
4525 		 * SMB privileges.
4526 		 */
4527 	case PRIV_NETSMB:
4528 #endif
4529 
4530 	/*
4531 	 * No default: or deny here.
4532 	 * In case of no permit fall through to next switch().
4533 	 */
4534 		if (cred->cr_prison->pr_flags & PR_VNET)
4535 			return (0);
4536 	}
4537 #endif /* VIMAGE */
4538 
4539 	switch (priv) {
4540 		/*
4541 		 * Allow ktrace privileges for root in jail.
4542 		 */
4543 	case PRIV_KTRACE:
4544 		return (0);
4545 
4546 		/*
4547 		 * Allow jailed processes to configure audit identity and
4548 		 * submit audit records (login, etc).  In the future we may
4549 		 * want to further refine the relationship between audit and
4550 		 * jail.
4551 		 */
4552 	case PRIV_AUDIT_GETAUDIT:
4553 	case PRIV_AUDIT_SETAUDIT:
4554 		if (cred->cr_prison->pr_allow & PR_ALLOW_SETAUDIT)
4555 			return (0);
4556 		else
4557 			return (EPERM);
4558 #if 0
4559 	case PRIV_AUDIT_SUBMIT:
4560 #endif
4561 
4562 		/*
4563 		 * Allow jailed processes to manipulate process UNIX
4564 		 * credentials in any way they see fit.
4565 		 */
4566 	case PRIV_CRED_SETCRED:
4567 	case PRIV_CRED_SETUID:
4568 	case PRIV_CRED_SETEUID:
4569 	case PRIV_CRED_SETGID:
4570 	case PRIV_CRED_SETEGID:
4571 	case PRIV_CRED_SETGROUPS:
4572 	case PRIV_CRED_SETREUID:
4573 	case PRIV_CRED_SETREGID:
4574 	case PRIV_CRED_SETRESUID:
4575 	case PRIV_CRED_SETRESGID:
4576 
4577 		/*
4578 		 * Jail implements visibility constraints already, so allow
4579 		 * jailed root to override uid/gid-based constraints.
4580 		 */
4581 	case PRIV_SEEOTHERGIDS:
4582 	case PRIV_SEEOTHERUIDS:
4583 	case PRIV_SEEJAILPROC:
4584 
4585 		/*
4586 		 * Jail implements inter-process debugging limits already, so
4587 		 * allow jailed root various debugging privileges.
4588 		 */
4589 	case PRIV_DEBUG_DIFFCRED:
4590 	case PRIV_DEBUG_SUGID:
4591 	case PRIV_DEBUG_UNPRIV:
4592 	case PRIV_DEBUG_DIFFJAIL:
4593 
4594 		/*
4595 		 * Allow jail to set various resource limits and login
4596 		 * properties, and for now, exceed process resource limits.
4597 		 */
4598 	case PRIV_PROC_LIMIT:
4599 	case PRIV_PROC_SETLOGIN:
4600 	case PRIV_PROC_SETRLIMIT:
4601 
4602 		/*
4603 		 * Debuggers should work in jails.
4604 		 */
4605 	case PRIV_PROC_MEM_WRITE:
4606 
4607 		/*
4608 		 * System V and POSIX IPC privileges are granted in jail.
4609 		 */
4610 	case PRIV_IPC_READ:
4611 	case PRIV_IPC_WRITE:
4612 	case PRIV_IPC_ADMIN:
4613 	case PRIV_IPC_MSGSIZE:
4614 	case PRIV_MQ_ADMIN:
4615 
4616 		/*
4617 		 * Jail operations within a jail work on child jails.
4618 		 */
4619 	case PRIV_JAIL_ATTACH:
4620 	case PRIV_JAIL_SET:
4621 	case PRIV_JAIL_REMOVE:
4622 
4623 		/*
4624 		 * Jail implements its own inter-process limits, so allow
4625 		 * root processes in jail to change scheduling on other
4626 		 * processes in the same jail.  Likewise for signalling.
4627 		 */
4628 	case PRIV_SCHED_DIFFCRED:
4629 	case PRIV_SCHED_CPUSET:
4630 	case PRIV_SCHED_DIFFJAIL:
4631 	case PRIV_SIGNAL_DIFFCRED:
4632 	case PRIV_SIGNAL_SUGID:
4633 	case PRIV_SIGNAL_DIFFJAIL:
4634 
4635 		/*
4636 		 * Allow jailed processes to write to sysctls marked as jail
4637 		 * writable.
4638 		 */
4639 	case PRIV_SYSCTL_WRITEJAIL:
4640 
4641 		/*
4642 		 * Allow root in jail to manage a variety of quota
4643 		 * properties.  These should likely be conditional on a
4644 		 * configuration option.
4645 		 */
4646 	case PRIV_VFS_GETQUOTA:
4647 	case PRIV_VFS_SETQUOTA:
4648 
4649 		/*
4650 		 * Since Jail relies on chroot() to implement file system
4651 		 * protections, grant many VFS privileges to root in jail.
4652 		 * Be careful to exclude mount-related and NFS-related
4653 		 * privileges.
4654 		 */
4655 	case PRIV_VFS_READ:
4656 	case PRIV_VFS_WRITE:
4657 	case PRIV_VFS_ADMIN:
4658 	case PRIV_VFS_EXEC:
4659 	case PRIV_VFS_BLOCKRESERVE:	/* XXXRW: Slightly surprising. */
4660 	case PRIV_VFS_CHFLAGS_DEV:
4661 	case PRIV_VFS_CHOWN:
4662 	case PRIV_VFS_CHROOT:
4663 	case PRIV_VFS_RETAINSUGID:
4664 	case PRIV_VFS_FCHROOT:
4665 	case PRIV_VFS_LINK:
4666 	case PRIV_VFS_SETGID:
4667 	case PRIV_VFS_STAT:
4668 	case PRIV_VFS_STICKYFILE:
4669 
4670 		/*
4671 		 * As in the non-jail case, non-root users are expected to be
4672 		 * able to read kernel/physical memory (provided /dev/[k]mem
4673 		 * exists in the jail and they have permission to access it).
4674 		 */
4675 	case PRIV_KMEM_READ:
4676 		return (0);
4677 
4678 		/*
4679 		 * Depending on the global setting, allow privilege of
4680 		 * setting system flags.
4681 		 */
4682 	case PRIV_VFS_SYSFLAGS:
4683 		if (cred->cr_prison->pr_allow & PR_ALLOW_CHFLAGS)
4684 			return (0);
4685 		else
4686 			return (EPERM);
4687 
4688 		/*
4689 		 * Depending on the global setting, allow privilege of
4690 		 * mounting/unmounting file systems.
4691 		 */
4692 	case PRIV_VFS_MOUNT:
4693 	case PRIV_VFS_UNMOUNT:
4694 	case PRIV_VFS_MOUNT_NONUSER:
4695 	case PRIV_VFS_MOUNT_OWNER:
4696 		pr = cred->cr_prison;
4697 		prison_lock(pr);
4698 		if (pr->pr_allow & PR_ALLOW_MOUNT && pr->pr_enforce_statfs < 2)
4699 			error = 0;
4700 		else
4701 			error = EPERM;
4702 		prison_unlock(pr);
4703 		return (error);
4704 
4705 		/*
4706 		 * Jails should hold no disposition on the PRIV_VFS_READ_DIR
4707 		 * policy.  priv_check_cred will not specifically allow it, and
4708 		 * we may want a MAC policy to allow it.
4709 		 */
4710 	case PRIV_VFS_READ_DIR:
4711 		return (0);
4712 
4713 		/*
4714 		 * Conditionally allow privileged process in the jail to
4715 		 * manipulate filesystem extended attributes in the system
4716 		 * namespace.
4717 		 */
4718 	case PRIV_VFS_EXTATTR_SYSTEM:
4719 		if ((cred->cr_prison->pr_allow & PR_ALLOW_EXTATTR) != 0)
4720 			return (0);
4721 		else
4722 			return (EPERM);
4723 
4724 		/*
4725 		 * Conditionnaly allow locking (unlocking) physical pages
4726 		 * in memory.
4727 		 */
4728 	case PRIV_VM_MLOCK:
4729 	case PRIV_VM_MUNLOCK:
4730 		if (cred->cr_prison->pr_allow & PR_ALLOW_MLOCK)
4731 			return (0);
4732 		else
4733 			return (EPERM);
4734 
4735 		/*
4736 		 * Conditionally allow jailed root to bind reserved ports.
4737 		 */
4738 	case PRIV_NETINET_RESERVEDPORT:
4739 		if (cred->cr_prison->pr_allow & PR_ALLOW_RESERVED_PORTS)
4740 			return (0);
4741 		else
4742 			return (EPERM);
4743 
4744 		/*
4745 		 * Allow jailed root to reuse in-use ports.
4746 		 */
4747 	case PRIV_NETINET_REUSEPORT:
4748 		return (0);
4749 
4750 		/*
4751 		 * Allow jailed root to set certain IPv4/6 (option) headers.
4752 		 */
4753 	case PRIV_NETINET_SETHDROPTS:
4754 		return (0);
4755 
4756 		/*
4757 		 * Conditionally allow creating raw sockets in jail.
4758 		 */
4759 	case PRIV_NETINET_RAW:
4760 		if (cred->cr_prison->pr_allow & PR_ALLOW_RAW_SOCKETS)
4761 			return (0);
4762 		else
4763 			return (EPERM);
4764 
4765 		/*
4766 		 * Since jail implements its own visibility limits on netstat
4767 		 * sysctls, allow getcred.  This allows identd to work in
4768 		 * jail.
4769 		 */
4770 	case PRIV_NETINET_GETCRED:
4771 		return (0);
4772 
4773 		/*
4774 		 * Allow jailed root to set loginclass.
4775 		 */
4776 	case PRIV_PROC_SETLOGINCLASS:
4777 		return (0);
4778 
4779 		/*
4780 		 * Do not allow a process inside a jail to read the kernel
4781 		 * message buffer unless explicitly permitted.
4782 		 */
4783 	case PRIV_MSGBUF:
4784 		if (cred->cr_prison->pr_allow & PR_ALLOW_READ_MSGBUF)
4785 			return (0);
4786 		return (EPERM);
4787 
4788 		/*
4789 		 * Conditionally allow privileged process in the jail adjust
4790 		 * machine time.
4791 		 */
4792 	case PRIV_ADJTIME:
4793 	case PRIV_NTP_ADJTIME:
4794 		if (cred->cr_prison->pr_allow &
4795 		    (PR_ALLOW_ADJTIME | PR_ALLOW_SETTIME)) {
4796 			return (0);
4797 		}
4798 		return (EPERM);
4799 
4800 		/*
4801 		 * Conditionally allow privileged process in the jail set
4802 		 * machine time.
4803 		 */
4804 	case PRIV_SETTIMEOFDAY:
4805 	case PRIV_CLOCK_SETTIME:
4806 		if (cred->cr_prison->pr_allow & PR_ALLOW_SETTIME)
4807 			return (0);
4808 		else
4809 			return (EPERM);
4810 
4811 		/*
4812 		 * Conditionally allow privileged process in the jail to modify
4813 		 * the routing table.
4814 		 */
4815 	case PRIV_NET_ROUTE:
4816 		if (cred->cr_prison->pr_allow & PR_ALLOW_ROUTING)
4817 			return (0);
4818 		else
4819 			return (EPERM);
4820 
4821 	case PRIV_VMM_CREATE:
4822 	case PRIV_VMM_DESTROY:
4823 		/*
4824 		 * Jailed root can create and destroy VMs; the vmm module
4825 		 * additionally checks for the allow.vmm flag.
4826 		 */
4827 		return (0);
4828 
4829 	case PRIV_VMM_PPTDEV:
4830 		/*
4831 		 * Allow jailed root to manage passthrough devices.  vmm(4) also
4832 		 * checks for the dynamically added allow.vmm_ppt.
4833 		 */
4834 		return (0);
4835 
4836 	default:
4837 		/*
4838 		 * In all remaining cases, deny the privilege request.  This
4839 		 * includes almost all network privileges, many system
4840 		 * configuration privileges.
4841 		 */
4842 		return (EPERM);
4843 	}
4844 }
4845 
4846 /*
4847  * Return the part of pr2's name that is relative to pr1, or the whole name
4848  * if it does not directly follow.
4849  */
4850 
4851 char *
4852 prison_name(struct prison *pr1, struct prison *pr2)
4853 {
4854 	char *name;
4855 
4856 	/* Jails see themselves as "0" (if they see themselves at all). */
4857 	if (pr1 == pr2)
4858 		return "0";
4859 	name = pr2->pr_name;
4860 	if (prison_ischild(pr1, pr2)) {
4861 		/*
4862 		 * pr1 isn't locked (and allprison_lock may not be either)
4863 		 * so its length can't be counted on.  But the number of dots
4864 		 * can be counted on - and counted.
4865 		 */
4866 		for (; pr1 != &prison0; pr1 = pr1->pr_parent)
4867 			name = strchr(name, '.') + 1;
4868 	}
4869 	return (name);
4870 }
4871 
4872 /*
4873  * Return the part of pr2's path that is relative to pr1, or the whole path
4874  * if it does not directly follow.
4875  */
4876 static char *
4877 prison_path(struct prison *pr1, struct prison *pr2)
4878 {
4879 	char *path1, *path2;
4880 	int len1;
4881 
4882 	path1 = pr1->pr_path;
4883 	path2 = pr2->pr_path;
4884 	if (!strcmp(path1, "/"))
4885 		return (path2);
4886 	len1 = strlen(path1);
4887 	if (strncmp(path1, path2, len1))
4888 		return (path2);
4889 	if (path2[len1] == '\0')
4890 		return "/";
4891 	if (path2[len1] == '/')
4892 		return (path2 + len1);
4893 	return (path2);
4894 }
4895 
4896 /*
4897  * Jail-related sysctls.
4898  */
4899 SYSCTL_NODE(_security, OID_AUTO, jail, CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
4900     "Jails");
4901 
4902 #if defined(INET) || defined(INET6)
4903 /*
4904  * Copy address array to memory that would be then SYSCTL_OUT-ed.
4905  * sysctl_jail_list() helper.
4906  */
4907 static void
4908 prison_ip_copyout(struct prison *pr, const pr_family_t af, void **out, int *len)
4909 {
4910 	const struct prison_ip *pip;
4911 	const size_t size = pr_families[af].size;
4912 
4913  again:
4914 	mtx_assert(&pr->pr_mtx, MA_OWNED);
4915 	if ((pip = pr->pr_addrs[af]) != NULL) {
4916 		if (*len < pip->ips) {
4917 			*len = pip->ips;
4918 			mtx_unlock(&pr->pr_mtx);
4919 			*out = realloc(*out, *len * size, M_TEMP, M_WAITOK);
4920 			mtx_lock(&pr->pr_mtx);
4921 			goto again;
4922 		}
4923 		bcopy(pip->pr_ip, *out, pip->ips * size);
4924 	}
4925 }
4926 #endif
4927 
4928 static int
4929 sysctl_jail_list(SYSCTL_HANDLER_ARGS)
4930 {
4931 	struct xprison *xp;
4932 	struct prison *pr, *cpr;
4933 #ifdef INET
4934 	struct in_addr *ip4 = NULL;
4935 	int ip4s = 0;
4936 #endif
4937 #ifdef INET6
4938 	struct in6_addr *ip6 = NULL;
4939 	int ip6s = 0;
4940 #endif
4941 	int descend, error;
4942 
4943 	xp = malloc(sizeof(*xp), M_TEMP, M_WAITOK);
4944 	pr = req->td->td_ucred->cr_prison;
4945 	error = 0;
4946 	sx_slock(&allprison_lock);
4947 	FOREACH_PRISON_DESCENDANT(pr, cpr, descend) {
4948 		mtx_lock(&cpr->pr_mtx);
4949 #ifdef INET
4950 		prison_ip_copyout(cpr, PR_INET, (void **)&ip4, &ip4s);
4951 #endif
4952 #ifdef INET6
4953 		prison_ip_copyout(cpr, PR_INET6, (void **)&ip6, &ip6s);
4954 #endif
4955 		bzero(xp, sizeof(*xp));
4956 		xp->pr_version = XPRISON_VERSION;
4957 		xp->pr_id = cpr->pr_id;
4958 		xp->pr_state = cpr->pr_state;
4959 		strlcpy(xp->pr_path, prison_path(pr, cpr), sizeof(xp->pr_path));
4960 		strlcpy(xp->pr_host, cpr->pr_hostname, sizeof(xp->pr_host));
4961 		strlcpy(xp->pr_name, prison_name(pr, cpr), sizeof(xp->pr_name));
4962 #ifdef INET
4963 		xp->pr_ip4s = ip4s;
4964 #endif
4965 #ifdef INET6
4966 		xp->pr_ip6s = ip6s;
4967 #endif
4968 		mtx_unlock(&cpr->pr_mtx);
4969 		error = SYSCTL_OUT(req, xp, sizeof(*xp));
4970 		if (error)
4971 			break;
4972 #ifdef INET
4973 		if (xp->pr_ip4s > 0) {
4974 			error = SYSCTL_OUT(req, ip4,
4975 			    xp->pr_ip4s * sizeof(struct in_addr));
4976 			if (error)
4977 				break;
4978 		}
4979 #endif
4980 #ifdef INET6
4981 		if (xp->pr_ip6s > 0) {
4982 			error = SYSCTL_OUT(req, ip6,
4983 			    xp->pr_ip6s * sizeof(struct in6_addr));
4984 			if (error)
4985 				break;
4986 		}
4987 #endif
4988 	}
4989 	sx_sunlock(&allprison_lock);
4990 	free(xp, M_TEMP);
4991 #ifdef INET
4992 	free(ip4, M_TEMP);
4993 #endif
4994 #ifdef INET6
4995 	free(ip6, M_TEMP);
4996 #endif
4997 	return (error);
4998 }
4999 
5000 SYSCTL_OID(_security_jail, OID_AUTO, list,
5001     CTLTYPE_STRUCT | CTLFLAG_RD | CTLFLAG_MPSAFE, NULL, 0,
5002     sysctl_jail_list, "S", "List of active jails");
5003 
5004 static int
5005 sysctl_jail_jailed(SYSCTL_HANDLER_ARGS)
5006 {
5007 	int error, injail;
5008 
5009 	injail = jailed(req->td->td_ucred);
5010 	error = SYSCTL_OUT(req, &injail, sizeof(injail));
5011 
5012 	return (error);
5013 }
5014 
5015 SYSCTL_PROC(_security_jail, OID_AUTO, jailed,
5016     CTLTYPE_INT | CTLFLAG_RD | CTLFLAG_MPSAFE, NULL, 0,
5017     sysctl_jail_jailed, "I", "Process in jail?");
5018 
5019 static int
5020 sysctl_jail_vnet(SYSCTL_HANDLER_ARGS)
5021 {
5022 	int error, havevnet;
5023 #ifdef VIMAGE
5024 	struct ucred *cred = req->td->td_ucred;
5025 
5026 	havevnet = jailed(cred) && prison_owns_vnet(cred->cr_prison);
5027 #else
5028 	havevnet = 0;
5029 #endif
5030 	error = SYSCTL_OUT(req, &havevnet, sizeof(havevnet));
5031 
5032 	return (error);
5033 }
5034 
5035 SYSCTL_PROC(_security_jail, OID_AUTO, vnet,
5036     CTLTYPE_INT | CTLFLAG_RD | CTLFLAG_MPSAFE, NULL, 0,
5037     sysctl_jail_vnet, "I", "Jail owns vnet?");
5038 
5039 #if defined(INET) || defined(INET6)
5040 SYSCTL_UINT(_security_jail, OID_AUTO, jail_max_af_ips, CTLFLAG_RW,
5041     &jail_max_af_ips, 0,
5042     "Number of IP addresses a jail may have at most per address family (deprecated)");
5043 #endif
5044 
5045 /*
5046  * Default parameters for jail(2) compatibility.  For historical reasons,
5047  * the sysctl names have varying similarity to the parameter names.  Prisons
5048  * just see their own parameters, and can't change them.
5049  */
5050 static int
5051 sysctl_jail_default_allow(SYSCTL_HANDLER_ARGS)
5052 {
5053 	int error, i;
5054 
5055 	/* Get the current flag value, and convert it to a boolean. */
5056 	if (req->td->td_ucred->cr_prison == &prison0) {
5057 		mtx_lock(&prison0.pr_mtx);
5058 		i = (jail_default_allow & arg2) != 0;
5059 		mtx_unlock(&prison0.pr_mtx);
5060 	} else
5061 		i = prison_allow(req->td->td_ucred, arg2);
5062 
5063 	if (arg1 != NULL)
5064 		i = !i;
5065 	error = sysctl_handle_int(oidp, &i, 0, req);
5066 	if (error || !req->newptr)
5067 		return (error);
5068 	i = i ? arg2 : 0;
5069 	if (arg1 != NULL)
5070 		i ^= arg2;
5071 	/*
5072 	 * The sysctls don't have CTLFLAGS_PRISON, so assume prison0
5073 	 * for writing.
5074 	 */
5075 	mtx_lock(&prison0.pr_mtx);
5076 	jail_default_allow = (jail_default_allow & ~arg2) | i;
5077 	mtx_unlock(&prison0.pr_mtx);
5078 	return (0);
5079 }
5080 
5081 /*
5082  * Do not add more here. Use SYSCTL_JAIL_PARAM (allow flags for jails)
5083  * instead.
5084  */
5085 SYSCTL_PROC(_security_jail, OID_AUTO, set_hostname_allowed,
5086     CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_MPSAFE,
5087     NULL, PR_ALLOW_SET_HOSTNAME, sysctl_jail_default_allow, "I",
5088     "Processes in jail can set their hostnames (deprecated)");
5089 SYSCTL_PROC(_security_jail, OID_AUTO, socket_unixiproute_only,
5090     CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_MPSAFE,
5091     (void *)1, PR_ALLOW_SOCKET_AF, sysctl_jail_default_allow, "I",
5092     "Processes in jail are limited to creating UNIX/IP/route sockets only (deprecated)");
5093 SYSCTL_PROC(_security_jail, OID_AUTO, sysvipc_allowed,
5094     CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_MPSAFE,
5095     NULL, PR_ALLOW_SYSVIPC, sysctl_jail_default_allow, "I",
5096     "Processes in jail can use System V IPC primitives (deprecated)");
5097 SYSCTL_PROC(_security_jail, OID_AUTO, allow_raw_sockets,
5098     CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_MPSAFE,
5099     NULL, PR_ALLOW_RAW_SOCKETS, sysctl_jail_default_allow, "I",
5100     "Prison root can create raw sockets (deprecated)");
5101 SYSCTL_PROC(_security_jail, OID_AUTO, chflags_allowed,
5102     CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_MPSAFE,
5103     NULL, PR_ALLOW_CHFLAGS, sysctl_jail_default_allow, "I",
5104     "Processes in jail can alter system file flags (deprecated)");
5105 SYSCTL_PROC(_security_jail, OID_AUTO, mount_allowed,
5106     CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_MPSAFE,
5107     NULL, PR_ALLOW_MOUNT, sysctl_jail_default_allow, "I",
5108     "Processes in jail can mount/unmount jail-friendly file systems (deprecated)");
5109 SYSCTL_PROC(_security_jail, OID_AUTO, mlock_allowed,
5110     CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_MPSAFE,
5111     NULL, PR_ALLOW_MLOCK, sysctl_jail_default_allow, "I",
5112     "Processes in jail can lock/unlock physical pages in memory (deprecated)");
5113 
5114 static int
5115 sysctl_jail_default_level(SYSCTL_HANDLER_ARGS)
5116 {
5117 	struct prison *pr;
5118 	int level, error;
5119 
5120 	pr = req->td->td_ucred->cr_prison;
5121 	level = (pr == &prison0) ? *(int *)arg1 : *(int *)((char *)pr + arg2);
5122 	error = sysctl_handle_int(oidp, &level, 0, req);
5123 	if (error || !req->newptr)
5124 		return (error);
5125 	*(int *)arg1 = level;
5126 	return (0);
5127 }
5128 
5129 SYSCTL_PROC(_security_jail, OID_AUTO, enforce_statfs,
5130     CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_MPSAFE,
5131     &jail_default_enforce_statfs, offsetof(struct prison, pr_enforce_statfs),
5132     sysctl_jail_default_level, "I",
5133     "Processes in jail cannot see all mounted file systems (deprecated)");
5134 
5135 SYSCTL_PROC(_security_jail, OID_AUTO, devfs_ruleset,
5136     CTLTYPE_INT | CTLFLAG_RD | CTLFLAG_MPSAFE,
5137     &jail_default_devfs_rsnum, offsetof(struct prison, pr_devfs_rsnum),
5138     sysctl_jail_default_level, "I",
5139     "Ruleset for the devfs filesystem in jail (deprecated)");
5140 
5141 SYSCTL_NODE(_security_jail, OID_AUTO, children, CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
5142     "Limits and stats of child jails");
5143 
5144 static int
5145 sysctl_jail_children(SYSCTL_HANDLER_ARGS)
5146 {
5147 	struct prison *pr;
5148 	int i;
5149 
5150 	pr = req->td->td_ucred->cr_prison;
5151 
5152 	switch (oidp->oid_kind & CTLTYPE) {
5153 	case CTLTYPE_INT:
5154 		i = *(int *)((char *)pr + arg2);
5155 		return (SYSCTL_OUT(req, &i, sizeof(i)));
5156 	}
5157 
5158 	return (0);
5159 }
5160 
5161 SYSCTL_PROC(_security_jail_children, OID_AUTO, max,
5162     CTLTYPE_INT | CTLFLAG_RD | CTLFLAG_MPSAFE,
5163     NULL, offsetof(struct prison, pr_childmax), sysctl_jail_children,
5164     "I", "Maximum number of child jails");
5165 SYSCTL_PROC(_security_jail_children, OID_AUTO, cur,
5166     CTLTYPE_INT | CTLFLAG_RD | CTLFLAG_MPSAFE,
5167     NULL, offsetof(struct prison, pr_childcount), sysctl_jail_children,
5168     "I", "Current number of child jails");
5169 
5170 /*
5171  * Nodes to describe jail parameters.  Maximum length of string parameters
5172  * is returned in the string itself, and the other parameters exist merely
5173  * to make themselves and their types known.
5174  */
5175 SYSCTL_NODE(_security_jail, OID_AUTO, param, CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
5176     "Jail parameters");
5177 
5178 int
5179 sysctl_jail_param(SYSCTL_HANDLER_ARGS)
5180 {
5181 	int i;
5182 	long l;
5183 	size_t s;
5184 	char numbuf[12];
5185 
5186 	switch (oidp->oid_kind & CTLTYPE)
5187 	{
5188 	case CTLTYPE_LONG:
5189 	case CTLTYPE_ULONG:
5190 		l = 0;
5191 #ifdef SCTL_MASK32
5192 		if (!(req->flags & SCTL_MASK32))
5193 #endif
5194 			return (SYSCTL_OUT(req, &l, sizeof(l)));
5195 	case CTLTYPE_INT:
5196 	case CTLTYPE_UINT:
5197 		i = 0;
5198 		return (SYSCTL_OUT(req, &i, sizeof(i)));
5199 	case CTLTYPE_STRING:
5200 		snprintf(numbuf, sizeof(numbuf), "%jd", (intmax_t)arg2);
5201 		return
5202 		    (sysctl_handle_string(oidp, numbuf, sizeof(numbuf), req));
5203 	case CTLTYPE_STRUCT:
5204 		s = (size_t)arg2;
5205 		return (SYSCTL_OUT(req, &s, sizeof(s)));
5206 	}
5207 	return (0);
5208 }
5209 
5210 /*
5211  * CTLFLAG_RDTUN in the following indicates jail parameters that can be set at
5212  * jail creation time but cannot be changed in an existing jail.
5213  */
5214 SYSCTL_JAIL_PARAM(, jid, CTLTYPE_INT | CTLFLAG_RDTUN, "I", "Jail ID");
5215 SYSCTL_JAIL_PARAM(, parent, CTLTYPE_INT | CTLFLAG_RD, "I", "Jail parent ID");
5216 SYSCTL_JAIL_PARAM_STRING(, name, CTLFLAG_RW, MAXHOSTNAMELEN, "Jail name");
5217 SYSCTL_JAIL_PARAM_STRING(, path, CTLFLAG_RDTUN, MAXPATHLEN, "Jail root path");
5218 SYSCTL_JAIL_PARAM(, securelevel, CTLTYPE_INT | CTLFLAG_RW,
5219     "I", "Jail secure level");
5220 SYSCTL_JAIL_PARAM(, osreldate, CTLTYPE_INT | CTLFLAG_RDTUN, "I",
5221     "Jail value for kern.osreldate and uname -K");
5222 SYSCTL_JAIL_PARAM_STRING(, osrelease, CTLFLAG_RDTUN, OSRELEASELEN,
5223     "Jail value for kern.osrelease and uname -r");
5224 SYSCTL_JAIL_PARAM(, enforce_statfs, CTLTYPE_INT | CTLFLAG_RW,
5225     "I", "Jail cannot see all mounted file systems");
5226 SYSCTL_JAIL_PARAM(, devfs_ruleset, CTLTYPE_INT | CTLFLAG_RW,
5227     "I", "Ruleset for in-jail devfs mounts");
5228 SYSCTL_JAIL_PARAM(, persist, CTLTYPE_INT | CTLFLAG_RW,
5229     "B", "Jail persistence");
5230 #ifdef VIMAGE
5231 SYSCTL_JAIL_PARAM(, vnet, CTLTYPE_INT | CTLFLAG_RDTUN,
5232     "E,jailsys", "Virtual network stack");
5233 #endif
5234 SYSCTL_JAIL_PARAM(, dying, CTLTYPE_INT | CTLFLAG_RD,
5235     "B", "Jail is in the process of shutting down");
5236 
5237 SYSCTL_JAIL_PARAM_NODE(children, "Number of child jails");
5238 SYSCTL_JAIL_PARAM(_children, cur, CTLTYPE_INT | CTLFLAG_RD,
5239     "I", "Current number of child jails");
5240 SYSCTL_JAIL_PARAM(_children, max, CTLTYPE_INT | CTLFLAG_RW,
5241     "I", "Maximum number of child jails");
5242 
5243 SYSCTL_JAIL_PARAM_SYS_NODE(host, CTLFLAG_RW, "Jail host info");
5244 SYSCTL_JAIL_PARAM_STRING(_host, hostname, CTLFLAG_RW, MAXHOSTNAMELEN,
5245     "Jail hostname");
5246 SYSCTL_JAIL_PARAM_STRING(_host, domainname, CTLFLAG_RW, MAXHOSTNAMELEN,
5247     "Jail NIS domainname");
5248 SYSCTL_JAIL_PARAM_STRING(_host, hostuuid, CTLFLAG_RW, HOSTUUIDLEN,
5249     "Jail host UUID");
5250 SYSCTL_JAIL_PARAM(_host, hostid, CTLTYPE_ULONG | CTLFLAG_RW,
5251     "LU", "Jail host ID");
5252 
5253 SYSCTL_JAIL_PARAM_NODE(cpuset, "Jail cpuset");
5254 SYSCTL_JAIL_PARAM(_cpuset, id, CTLTYPE_INT | CTLFLAG_RD, "I", "Jail cpuset ID");
5255 
5256 #ifdef MAC
5257 SYSCTL_JAIL_PARAM_STRUCT(_mac, label, CTLFLAG_RW, sizeof(struct mac),
5258     "S,mac", "Jail MAC label");
5259 #endif
5260 
5261 #ifdef INET
5262 SYSCTL_JAIL_PARAM_SYS_NODE(ip4, CTLFLAG_RDTUN,
5263     "Jail IPv4 address virtualization");
5264 SYSCTL_JAIL_PARAM_STRUCT(_ip4, addr, CTLFLAG_RW, sizeof(struct in_addr),
5265     "S,in_addr,a", "Jail IPv4 addresses");
5266 SYSCTL_JAIL_PARAM(_ip4, saddrsel, CTLTYPE_INT | CTLFLAG_RW,
5267     "B", "Do (not) use IPv4 source address selection rather than the "
5268     "primary jail IPv4 address.");
5269 #endif
5270 #ifdef INET6
5271 SYSCTL_JAIL_PARAM_SYS_NODE(ip6, CTLFLAG_RDTUN,
5272     "Jail IPv6 address virtualization");
5273 SYSCTL_JAIL_PARAM_STRUCT(_ip6, addr, CTLFLAG_RW, sizeof(struct in6_addr),
5274     "S,in6_addr,a", "Jail IPv6 addresses");
5275 SYSCTL_JAIL_PARAM(_ip6, saddrsel, CTLTYPE_INT | CTLFLAG_RW,
5276     "B", "Do (not) use IPv6 source address selection rather than the "
5277     "primary jail IPv6 address.");
5278 #endif
5279 
5280 SYSCTL_JAIL_PARAM_NODE(allow, "Jail permission flags");
5281 SYSCTL_JAIL_PARAM(_allow, set_hostname, CTLTYPE_INT | CTLFLAG_RW,
5282     "B", "Jail may set hostname");
5283 SYSCTL_JAIL_PARAM(_allow, sysvipc, CTLTYPE_INT | CTLFLAG_RW,
5284     "B", "Jail may use SYSV IPC");
5285 SYSCTL_JAIL_PARAM(_allow, raw_sockets, CTLTYPE_INT | CTLFLAG_RW,
5286     "B", "Jail may create raw sockets");
5287 SYSCTL_JAIL_PARAM(_allow, chflags, CTLTYPE_INT | CTLFLAG_RW,
5288     "B", "Jail may alter system file flags");
5289 SYSCTL_JAIL_PARAM(_allow, quotas, CTLTYPE_INT | CTLFLAG_RW,
5290     "B", "Jail may set file quotas");
5291 SYSCTL_JAIL_PARAM(_allow, socket_af, CTLTYPE_INT | CTLFLAG_RW,
5292     "B", "Jail may create sockets other than just UNIX/IPv4/IPv6/route");
5293 SYSCTL_JAIL_PARAM(_allow, mlock, CTLTYPE_INT | CTLFLAG_RW,
5294     "B", "Jail may lock (unlock) physical pages in memory");
5295 SYSCTL_JAIL_PARAM(_allow, reserved_ports, CTLTYPE_INT | CTLFLAG_RW,
5296     "B", "Jail may bind sockets to reserved ports");
5297 SYSCTL_JAIL_PARAM(_allow, read_msgbuf, CTLTYPE_INT | CTLFLAG_RW,
5298     "B", "Jail may read the kernel message buffer");
5299 SYSCTL_JAIL_PARAM(_allow, unprivileged_proc_debug, CTLTYPE_INT | CTLFLAG_RW,
5300     "B", "Unprivileged processes may use process debugging facilities");
5301 SYSCTL_JAIL_PARAM(_allow, unprivileged_parent_tampering,
5302     CTLTYPE_INT | CTLFLAG_RW, "B",
5303     "Unprivileged parent jail processes may tamper with same-uid processes"
5304     " (signal/debug/cpuset)");
5305 SYSCTL_JAIL_PARAM(_allow, suser, CTLTYPE_INT | CTLFLAG_RW,
5306     "B", "Processes in jail with uid 0 have privilege");
5307 #ifdef VIMAGE
5308 SYSCTL_JAIL_PARAM(_allow, nfsd, CTLTYPE_INT | CTLFLAG_RW,
5309     "B", "Mountd/nfsd may run in the jail");
5310 #endif
5311 SYSCTL_JAIL_PARAM(_allow, extattr, CTLTYPE_INT | CTLFLAG_RW,
5312     "B", "Jail may set system-level filesystem extended attributes");
5313 SYSCTL_JAIL_PARAM(_allow, adjtime, CTLTYPE_INT | CTLFLAG_RW,
5314     "B", "Jail may adjust system time");
5315 SYSCTL_JAIL_PARAM(_allow, settime, CTLTYPE_INT | CTLFLAG_RW,
5316     "B", "Jail may set system time");
5317 SYSCTL_JAIL_PARAM(_allow, routing, CTLTYPE_INT | CTLFLAG_RW,
5318     "B", "Jail may modify routing table");
5319 #ifdef AUDIT
5320 SYSCTL_JAIL_PARAM(_allow, setaudit, CTLTYPE_INT | CTLFLAG_RW,
5321     "B", "Jail may set and get audit session state");
5322 #endif
5323 
5324 SYSCTL_JAIL_PARAM_SUBNODE(allow, mount, "Jail mount/unmount permission flags");
5325 SYSCTL_JAIL_PARAM(_allow_mount, , CTLTYPE_INT | CTLFLAG_RW,
5326     "B", "Jail may mount/unmount jail-friendly file systems in general");
5327 
5328 /*
5329  * Add a dynamic parameter allow.<name>, or allow.<prefix>.<name>.  Return
5330  * its associated bit in the pr_allow bitmask, or zero if the parameter was
5331  * not created.
5332  */
5333 unsigned
5334 prison_add_allow(const char *prefix, const char *name, const char *prefix_descr,
5335     const char *descr)
5336 {
5337 	struct bool_flags *bf;
5338 	struct sysctl_oid *parent;
5339 	char *allow_name, *allow_noname, *allowed;
5340 #ifndef NO_SYSCTL_DESCR
5341 	char *descr_deprecated;
5342 #endif
5343 	u_int allow_flag;
5344 
5345 	if (prefix
5346 	    ? asprintf(&allow_name, M_PRISON, "allow.%s.%s", prefix, name)
5347 		< 0 ||
5348 	      asprintf(&allow_noname, M_PRISON, "allow.%s.no%s", prefix, name)
5349 		< 0
5350 	    : asprintf(&allow_name, M_PRISON, "allow.%s", name) < 0 ||
5351 	      asprintf(&allow_noname, M_PRISON, "allow.no%s", name) < 0) {
5352 		free(allow_name, M_PRISON);
5353 		return 0;
5354 	}
5355 
5356 	/*
5357 	 * See if this parameter has already beed added, i.e. a module was
5358 	 * previously loaded/unloaded.
5359 	 */
5360 	mtx_lock(&prison0.pr_mtx);
5361 	for (bf = pr_flag_allow;
5362 	     bf < pr_flag_allow + nitems(pr_flag_allow) &&
5363 		atomic_load_int(&bf->flag) != 0;
5364 	     bf++) {
5365 		if (strcmp(bf->name, allow_name) == 0) {
5366 			allow_flag = bf->flag;
5367 			goto no_add;
5368 		}
5369 	}
5370 
5371 	/*
5372 	 * Find a free bit in pr_allow_all, failing if there are none
5373 	 * (which shouldn't happen as long as we keep track of how many
5374 	 * potential dynamic flags exist).
5375 	 */
5376 	for (allow_flag = 1;; allow_flag <<= 1) {
5377 		if (allow_flag == 0)
5378 			goto no_add;
5379 		if ((pr_allow_all & allow_flag) == 0)
5380 			break;
5381 	}
5382 
5383 	/* Note the parameter in the next open slot in pr_flag_allow. */
5384 	for (bf = pr_flag_allow; ; bf++) {
5385 		if (bf == pr_flag_allow + nitems(pr_flag_allow)) {
5386 			/* This should never happen, but is not fatal. */
5387 			allow_flag = 0;
5388 			goto no_add;
5389 		}
5390 		if (atomic_load_int(&bf->flag) == 0)
5391 			break;
5392 	}
5393 	bf->name = allow_name;
5394 	bf->noname = allow_noname;
5395 	pr_allow_all |= allow_flag;
5396 	/*
5397 	 * prison0 always has permission for the new parameter.
5398 	 * Other jails must have it granted to them.
5399 	 */
5400 	prison0.pr_allow |= allow_flag;
5401 	/* The flag indicates a valid entry, so make sure it is set last. */
5402 	atomic_store_rel_int(&bf->flag, allow_flag);
5403 	mtx_unlock(&prison0.pr_mtx);
5404 
5405 	/*
5406 	 * Create sysctls for the parameter, and the back-compat global
5407 	 * permission.
5408 	 */
5409 	parent = prefix
5410 	    ? SYSCTL_ADD_NODE(NULL,
5411 		  SYSCTL_CHILDREN(&sysctl___security_jail_param_allow),
5412 		  OID_AUTO, prefix, CTLFLAG_MPSAFE, 0, prefix_descr)
5413 	    : &sysctl___security_jail_param_allow;
5414 	(void)SYSCTL_ADD_PROC(NULL, SYSCTL_CHILDREN(parent), OID_AUTO,
5415 	    name, CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_MPSAFE,
5416 	    NULL, 0, sysctl_jail_param, "B", descr);
5417 	if ((prefix
5418 	     ? asprintf(&allowed, M_TEMP, "%s_%s_allowed", prefix, name)
5419 	     : asprintf(&allowed, M_TEMP, "%s_allowed", name)) >= 0) {
5420 #ifndef NO_SYSCTL_DESCR
5421 		(void)asprintf(&descr_deprecated, M_TEMP, "%s (deprecated)",
5422 		    descr);
5423 #endif
5424 		(void)SYSCTL_ADD_PROC(NULL,
5425 		    SYSCTL_CHILDREN(&sysctl___security_jail), OID_AUTO, allowed,
5426 		    CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_MPSAFE, NULL, allow_flag,
5427 		    sysctl_jail_default_allow, "I", descr_deprecated);
5428 #ifndef NO_SYSCTL_DESCR
5429 		free(descr_deprecated, M_TEMP);
5430 #endif
5431 		free(allowed, M_TEMP);
5432 	}
5433 	return allow_flag;
5434 
5435  no_add:
5436 	mtx_unlock(&prison0.pr_mtx);
5437 	free(allow_name, M_PRISON);
5438 	free(allow_noname, M_PRISON);
5439 	return allow_flag;
5440 }
5441 
5442 /*
5443  * The VFS system will register jail-aware filesystems here.  They each get
5444  * a parameter allow.mount.xxxfs and a flag to check when a jailed user
5445  * attempts to mount.
5446  */
5447 void
5448 prison_add_vfs(struct vfsconf *vfsp)
5449 {
5450 #ifdef NO_SYSCTL_DESCR
5451 
5452 	vfsp->vfc_prison_flag = prison_add_allow("mount", vfsp->vfc_name,
5453 	    NULL, NULL);
5454 #else
5455 	char *descr;
5456 
5457 	(void)asprintf(&descr, M_TEMP, "Jail may mount the %s file system",
5458 	    vfsp->vfc_name);
5459 	vfsp->vfc_prison_flag = prison_add_allow("mount", vfsp->vfc_name,
5460 	    NULL, descr);
5461 	free(descr, M_TEMP);
5462 #endif
5463 }
5464 
5465 #ifdef RACCT
5466 void
5467 prison_racct_foreach(void (*callback)(struct racct *racct,
5468     void *arg2, void *arg3), void (*pre)(void), void (*post)(void),
5469     void *arg2, void *arg3)
5470 {
5471 	struct prison_racct *prr;
5472 
5473 	ASSERT_RACCT_ENABLED();
5474 
5475 	sx_slock(&allprison_lock);
5476 	if (pre != NULL)
5477 		(pre)();
5478 	LIST_FOREACH(prr, &allprison_racct, prr_next)
5479 		(callback)(prr->prr_racct, arg2, arg3);
5480 	if (post != NULL)
5481 		(post)();
5482 	sx_sunlock(&allprison_lock);
5483 }
5484 
5485 static struct prison_racct *
5486 prison_racct_find_locked(const char *name)
5487 {
5488 	struct prison_racct *prr;
5489 
5490 	ASSERT_RACCT_ENABLED();
5491 	sx_assert(&allprison_lock, SA_XLOCKED);
5492 
5493 	if (name[0] == '\0' || strlen(name) >= MAXHOSTNAMELEN)
5494 		return (NULL);
5495 
5496 	LIST_FOREACH(prr, &allprison_racct, prr_next) {
5497 		if (strcmp(name, prr->prr_name) != 0)
5498 			continue;
5499 
5500 		/* Found prison_racct with a matching name? */
5501 		prison_racct_hold(prr);
5502 		return (prr);
5503 	}
5504 
5505 	/* Add new prison_racct. */
5506 	prr = malloc(sizeof(*prr), M_PRISON_RACCT, M_ZERO | M_WAITOK);
5507 	racct_create(&prr->prr_racct);
5508 
5509 	strcpy(prr->prr_name, name);
5510 	refcount_init(&prr->prr_refcount, 1);
5511 	LIST_INSERT_HEAD(&allprison_racct, prr, prr_next);
5512 
5513 	return (prr);
5514 }
5515 
5516 struct prison_racct *
5517 prison_racct_find(const char *name)
5518 {
5519 	struct prison_racct *prr;
5520 
5521 	ASSERT_RACCT_ENABLED();
5522 
5523 	sx_xlock(&allprison_lock);
5524 	prr = prison_racct_find_locked(name);
5525 	sx_xunlock(&allprison_lock);
5526 	return (prr);
5527 }
5528 
5529 void
5530 prison_racct_hold(struct prison_racct *prr)
5531 {
5532 
5533 	ASSERT_RACCT_ENABLED();
5534 
5535 	refcount_acquire(&prr->prr_refcount);
5536 }
5537 
5538 static void
5539 prison_racct_free_locked(struct prison_racct *prr)
5540 {
5541 
5542 	ASSERT_RACCT_ENABLED();
5543 	sx_assert(&allprison_lock, SA_XLOCKED);
5544 
5545 	if (refcount_release(&prr->prr_refcount)) {
5546 		racct_destroy(&prr->prr_racct);
5547 		LIST_REMOVE(prr, prr_next);
5548 		free(prr, M_PRISON_RACCT);
5549 	}
5550 }
5551 
5552 void
5553 prison_racct_free(struct prison_racct *prr)
5554 {
5555 
5556 	ASSERT_RACCT_ENABLED();
5557 	sx_assert(&allprison_lock, SA_UNLOCKED);
5558 
5559 	if (refcount_release_if_not_last(&prr->prr_refcount))
5560 		return;
5561 
5562 	sx_xlock(&allprison_lock);
5563 	prison_racct_free_locked(prr);
5564 	sx_xunlock(&allprison_lock);
5565 }
5566 
5567 static void
5568 prison_racct_attach(struct prison *pr)
5569 {
5570 	struct prison_racct *prr;
5571 
5572 	ASSERT_RACCT_ENABLED();
5573 	sx_assert(&allprison_lock, SA_XLOCKED);
5574 
5575 	prr = prison_racct_find_locked(pr->pr_name);
5576 	KASSERT(prr != NULL, ("cannot find prison_racct"));
5577 
5578 	pr->pr_prison_racct = prr;
5579 }
5580 
5581 /*
5582  * Handle jail renaming.  From the racct point of view, renaming means
5583  * moving from one prison_racct to another.
5584  */
5585 static void
5586 prison_racct_modify(struct prison *pr)
5587 {
5588 #ifdef RCTL
5589 	struct proc *p;
5590 	struct ucred *cred;
5591 #endif
5592 	struct prison_racct *oldprr;
5593 
5594 	ASSERT_RACCT_ENABLED();
5595 
5596 	sx_slock(&allproc_lock);
5597 	sx_xlock(&allprison_lock);
5598 
5599 	if (strcmp(pr->pr_name, pr->pr_prison_racct->prr_name) == 0) {
5600 		sx_xunlock(&allprison_lock);
5601 		sx_sunlock(&allproc_lock);
5602 		return;
5603 	}
5604 
5605 	oldprr = pr->pr_prison_racct;
5606 	pr->pr_prison_racct = NULL;
5607 
5608 	prison_racct_attach(pr);
5609 
5610 	/*
5611 	 * Move resource utilisation records.
5612 	 */
5613 	racct_move(pr->pr_prison_racct->prr_racct, oldprr->prr_racct);
5614 
5615 #ifdef RCTL
5616 	/*
5617 	 * Force rctl to reattach rules to processes.
5618 	 */
5619 	FOREACH_PROC_IN_SYSTEM(p) {
5620 		PROC_LOCK(p);
5621 		cred = crhold(p->p_ucred);
5622 		PROC_UNLOCK(p);
5623 		rctl_proc_ucred_changed(p, cred);
5624 		crfree(cred);
5625 	}
5626 #endif
5627 
5628 	sx_sunlock(&allproc_lock);
5629 	prison_racct_free_locked(oldprr);
5630 	sx_xunlock(&allprison_lock);
5631 }
5632 
5633 static void
5634 prison_racct_detach(struct prison *pr)
5635 {
5636 
5637 	ASSERT_RACCT_ENABLED();
5638 	sx_assert(&allprison_lock, SA_UNLOCKED);
5639 
5640 	if (pr->pr_prison_racct == NULL)
5641 		return;
5642 	prison_racct_free(pr->pr_prison_racct);
5643 	pr->pr_prison_racct = NULL;
5644 }
5645 #endif /* RACCT */
5646 
5647 /*
5648  * Submit a knote for a prison, locking if necessary.
5649  */
5650 static void
5651 prison_knote(struct prison *pr, long hint)
5652 {
5653 	int locked;
5654 
5655 	locked = mtx_owned(&pr->pr_mtx);
5656 	if (!locked)
5657 		mtx_lock(&pr->pr_mtx);
5658 	KNOTE_LOCKED(pr->pr_klist, hint);
5659 	jaildesc_knote(pr, hint);
5660 	if (!locked)
5661 		mtx_unlock(&pr->pr_mtx);
5662 }
5663 
5664 #ifdef DDB
5665 
5666 static void
5667 db_show_prison(struct prison *pr)
5668 {
5669 	struct bool_flags *bf;
5670 	struct jailsys_flags *jsf;
5671 #if defined(INET) || defined(INET6)
5672 	int ii;
5673 	struct prison_ip *pip;
5674 #endif
5675 	unsigned f;
5676 #ifdef INET
5677 	char ip4buf[INET_ADDRSTRLEN];
5678 #endif
5679 #ifdef INET6
5680 	char ip6buf[INET6_ADDRSTRLEN];
5681 #endif
5682 
5683 	db_printf("prison %p:\n", pr);
5684 	db_printf(" jid             = %d\n", pr->pr_id);
5685 	db_printf(" name            = %s\n", pr->pr_name);
5686 	db_printf(" parent          = %p\n", pr->pr_parent);
5687 	db_printf(" ref             = %d\n", pr->pr_ref);
5688 	db_printf(" uref            = %d\n", pr->pr_uref);
5689 	db_printf(" state           = %s\n",
5690 	    pr->pr_state == PRISON_STATE_ALIVE ? "alive" :
5691 	    pr->pr_state == PRISON_STATE_DYING ? "dying" :
5692 	    "invalid");
5693 	db_printf(" path            = %s\n", pr->pr_path);
5694 	db_printf(" cpuset          = %d\n", pr->pr_cpuset
5695 	    ? pr->pr_cpuset->cs_id : -1);
5696 #ifdef VIMAGE
5697 	db_printf(" vnet            = %p\n", pr->pr_vnet);
5698 #endif
5699 	db_printf(" root            = %p\n", pr->pr_root);
5700 	db_printf(" securelevel     = %d\n", pr->pr_securelevel);
5701 	db_printf(" devfs_rsnum     = %d\n", pr->pr_devfs_rsnum);
5702 	db_printf(" children.max    = %d\n", pr->pr_childmax);
5703 	db_printf(" children.cur    = %d\n", pr->pr_childcount);
5704 	db_printf(" child           = %p\n", LIST_FIRST(&pr->pr_children));
5705 	db_printf(" sibling         = %p\n", LIST_NEXT(pr, pr_sibling));
5706 	db_printf(" flags           = 0x%x", pr->pr_flags);
5707 	for (bf = pr_flag_bool; bf < pr_flag_bool + nitems(pr_flag_bool); bf++)
5708 		if (pr->pr_flags & bf->flag)
5709 			db_printf(" %s", bf->name);
5710 	for (jsf = pr_flag_jailsys;
5711 	     jsf < pr_flag_jailsys + nitems(pr_flag_jailsys);
5712 	     jsf++) {
5713 		f = pr->pr_flags & (jsf->disable | jsf->new);
5714 		db_printf(" %-16s= %s\n", jsf->name,
5715 		    (f != 0 && f == jsf->disable) ? "disable"
5716 		    : (f == jsf->new) ? "new"
5717 		    : "inherit");
5718 	}
5719 	db_printf(" allow           = 0x%x", pr->pr_allow);
5720 	for (bf = pr_flag_allow;
5721 	     bf < pr_flag_allow + nitems(pr_flag_allow) &&
5722 		atomic_load_int(&bf->flag) != 0;
5723 	     bf++)
5724 		if (pr->pr_allow & bf->flag)
5725 			db_printf(" %s", bf->name);
5726 	db_printf("\n");
5727 	db_printf(" enforce_statfs  = %d\n", pr->pr_enforce_statfs);
5728 	db_printf(" host.hostname   = %s\n", pr->pr_hostname);
5729 	db_printf(" host.domainname = %s\n", pr->pr_domainname);
5730 	db_printf(" host.hostuuid   = %s\n", pr->pr_hostuuid);
5731 	db_printf(" host.hostid     = %lu\n", pr->pr_hostid);
5732 #ifdef INET
5733 	if ((pip = pr->pr_addrs[PR_INET]) != NULL) {
5734 		db_printf(" ip4s            = %d\n", pip->ips);
5735 		for (ii = 0; ii < pip->ips; ii++)
5736 			db_printf(" %s %s\n",
5737 			    ii == 0 ? "ip4.addr        =" : "                 ",
5738 			    inet_ntoa_r(
5739 			    *(const struct in_addr *)PR_IP(pip, PR_INET, ii),
5740 			    ip4buf));
5741 	}
5742 #endif
5743 #ifdef INET6
5744 	if ((pip = pr->pr_addrs[PR_INET6]) != NULL) {
5745 		db_printf(" ip6s            = %d\n", pip->ips);
5746 		for (ii = 0; ii < pip->ips; ii++)
5747 			db_printf(" %s %s\n",
5748 			    ii == 0 ? "ip6.addr        =" : "                 ",
5749 			    ip6_sprintf(ip6buf,
5750 			    (const struct in6_addr *)PR_IP(pip, PR_INET6, ii)));
5751 	}
5752 #endif
5753 }
5754 
5755 DB_SHOW_COMMAND(prison, db_show_prison_command)
5756 {
5757 	struct prison *pr;
5758 
5759 	if (!have_addr) {
5760 		/*
5761 		 * Show all prisons in the list, and prison0 which is not
5762 		 * listed.
5763 		 */
5764 		db_show_prison(&prison0);
5765 		if (!db_pager_quit) {
5766 			TAILQ_FOREACH(pr, &allprison, pr_list) {
5767 				db_show_prison(pr);
5768 				if (db_pager_quit)
5769 					break;
5770 			}
5771 		}
5772 		return;
5773 	}
5774 
5775 	if (addr == 0)
5776 		pr = &prison0;
5777 	else {
5778 		/* Look for a prison with the ID and with references. */
5779 		TAILQ_FOREACH(pr, &allprison, pr_list)
5780 			if (pr->pr_id == addr && pr->pr_ref > 0)
5781 				break;
5782 		if (pr == NULL)
5783 			/* Look again, without requiring a reference. */
5784 			TAILQ_FOREACH(pr, &allprison, pr_list)
5785 				if (pr->pr_id == addr)
5786 					break;
5787 		if (pr == NULL)
5788 			/* Assume address points to a valid prison. */
5789 			pr = (struct prison *)addr;
5790 	}
5791 	db_show_prison(pr);
5792 }
5793 
5794 #endif /* DDB */
5795