xref: /freebsd/sys/kern/kern_jail.c (revision 679e13901cd9ae2a491e6ac63c29c7d60e581deb)

/*-
 * Copyright (c) 1999 Poul-Henning Kamp.
 * Copyright (c) 2008 Bjoern A. Zeeb.
 * Copyright (c) 2009 James Gritton.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");

#include "opt_compat.h"
#include "opt_ddb.h"
#include "opt_inet.h"
#include "opt_inet6.h"

#include <sys/param.h>
#include <sys/types.h>
#include <sys/kernel.h>
#include <sys/systm.h>
#include <sys/errno.h>
#include <sys/sysproto.h>
#include <sys/malloc.h>
#include <sys/osd.h>
#include <sys/priv.h>
#include <sys/proc.h>
#include <sys/taskqueue.h>
#include <sys/fcntl.h>
#include <sys/jail.h>
#include <sys/lock.h>
#include <sys/mutex.h>
#include <sys/sx.h>
#include <sys/sysent.h>
#include <sys/namei.h>
#include <sys/mount.h>
#include <sys/queue.h>
#include <sys/socket.h>
#include <sys/syscallsubr.h>
#include <sys/sysctl.h>
#include <sys/vnode.h>
#include <sys/vimage.h>
#include <net/if.h>
#include <netinet/in.h>
#ifdef DDB
#include <ddb/ddb.h>
#ifdef INET6
#include <netinet6/in6_var.h>
#endif /* INET6 */
#endif /* DDB */

#include <security/mac/mac_framework.h>

MALLOC_DEFINE(M_PRISON, "prison", "Prison structures");

/* prison0 describes what is "real" about the system. */
struct prison prison0 = {
	.pr_id		= 0,
	.pr_name	= "0",
	.pr_ref		= 1,
	.pr_uref	= 1,
	.pr_path	= "/",
	.pr_securelevel	= -1,
	.pr_hostuuid	= "00000000-0000-0000-0000-000000000000",
	.pr_children	= LIST_HEAD_INITIALIZER(&prison0.pr_children),
	.pr_flags	= PR_HOST,
	.pr_allow	= PR_ALLOW_ALL,
};
MTX_SYSINIT(prison0, &prison0.pr_mtx, "jail mutex", MTX_DEF);

/* allprison and lastprid are protected by allprison_lock. */
struct	sx allprison_lock;
SX_SYSINIT(allprison_lock, &allprison_lock, "allprison");
struct	prisonlist allprison = TAILQ_HEAD_INITIALIZER(allprison);
int	lastprid = 0;

static int do_jail_attach(struct thread *td, struct prison *pr);
static void prison_complete(void *context, int pending);
static void prison_deref(struct prison *pr, int flags);
static char *prison_path(struct prison *pr1, struct prison *pr2);
static void prison_remove_one(struct prison *pr);
#ifdef INET
static int _prison_check_ip4(struct prison *pr, struct in_addr *ia);
static int prison_restrict_ip4(struct prison *pr, struct in_addr *newip4);
#endif
#ifdef INET6
static int _prison_check_ip6(struct prison *pr, struct in6_addr *ia6);
static int prison_restrict_ip6(struct prison *pr, struct in6_addr *newip6);
#endif

/* Flags for prison_deref */
#define	PD_DEREF	0x01
#define	PD_DEUREF	0x02
#define	PD_LOCKED	0x04
#define	PD_LIST_SLOCKED	0x08
#define	PD_LIST_XLOCKED	0x10

/*
 * Parameter names corresponding to PR_* flag values
 */
static char *pr_flag_names[] = {
	[0] = "persist",
	"host",
#ifdef INET
	"ip4",
#endif
#ifdef INET6
	[3] = "ip6",
#endif
#ifdef VIMAGE
	[4] = "vnet",
#endif
};

static char *pr_flag_nonames[] = {
	[0] = "nopersist",
	"nohost",
#ifdef INET
	"noip4",
#endif
#ifdef INET6
	[3] = "noip6",
#endif
#ifdef VIMAGE
	[4] = "novnet",
#endif
};

static char *pr_allow_names[] = {
	"allow.set_hostname",
	"allow.sysvipc",
	"allow.raw_sockets",
	"allow.chflags",
	"allow.mount",
	"allow.quotas",
	"allow.jails",
	"allow.socket_af",
};

static char *pr_allow_nonames[] = {
	"allow.noset_hostname",
	"allow.nosysvipc",
	"allow.noraw_sockets",
	"allow.nochflags",
	"allow.nomount",
	"allow.noquotas",
	"allow.nojails",
	"allow.nosocket_af",
};

#define	JAIL_DEFAULT_ALLOW	PR_ALLOW_SET_HOSTNAME
static unsigned jail_default_allow = JAIL_DEFAULT_ALLOW;
static int jail_default_enforce_statfs = 2;
#if defined(INET) || defined(INET6)
static unsigned jail_max_af_ips = 255;
#endif

#ifdef INET
static int
qcmp_v4(const void *ip1, const void *ip2)
{
	in_addr_t iaa, iab;

	/*
	 * We need to compare in HBO here to get the list sorted as expected
	 * by the result of the code.  Sorting NBO addresses gives you
	 * interesting results.  If you do not understand, do not try.
	 */
	iaa = ntohl(((const struct in_addr *)ip1)->s_addr);
	iab = ntohl(((const struct in_addr *)ip2)->s_addr);

	/*
	 * Do not simply return the difference of the two numbers, the int is
	 * not wide enough.
	 */
	if (iaa > iab)
		return (1);
	else if (iaa < iab)
		return (-1);
	else
		return (0);
}
#endif

#ifdef INET6
static int
qcmp_v6(const void *ip1, const void *ip2)
{
	const struct in6_addr *ia6a, *ia6b;
	int i, rc;

	ia6a = (const struct in6_addr *)ip1;
	ia6b = (const struct in6_addr *)ip2;

	rc = 0;
	for (i = 0; rc == 0 && i < sizeof(struct in6_addr); i++) {
		if (ia6a->s6_addr[i] > ia6b->s6_addr[i])
			rc = 1;
		else if (ia6a->s6_addr[i] < ia6b->s6_addr[i])
			rc = -1;
	}
	return (rc);
}
#endif

/*
 * struct jail_args {
 *	struct jail *jail;
 * };
 */
int
jail(struct thread *td, struct jail_args *uap)
{
	uint32_t version;
	int error;
	struct jail j;

	error = copyin(uap->jail, &version, sizeof(uint32_t));
	if (error)
		return (error);

	switch (version) {
	case 0:
	{
		struct jail_v0 j0;

		/* FreeBSD single IPv4 jails. */
		bzero(&j, sizeof(struct jail));
		error = copyin(uap->jail, &j0, sizeof(struct jail_v0));
		if (error)
			return (error);
		j.version = j0.version;
		j.path = j0.path;
		j.hostname = j0.hostname;
		j.ip4s = j0.ip_number;
		break;
	}

	case 1:
		/*
		 * Version 1 was used by multi-IPv4 jail implementations
		 * that never made it into the official kernel.
		 */
		return (EINVAL);

	case 2:	/* JAIL_API_VERSION */
		/* FreeBSD multi-IPv4/IPv6,noIP jails. */
		error = copyin(uap->jail, &j, sizeof(struct jail));
		if (error)
			return (error);
		break;

	default:
		/* Sci-Fi jails are not supported, sorry. */
		return (EINVAL);
	}
	return (kern_jail(td, &j));
}

int
kern_jail(struct thread *td, struct jail *j)
{
	struct iovec optiov[2 * (4
			    + sizeof(pr_allow_names) / sizeof(pr_allow_names[0])
#ifdef INET
			    + 1
#endif
#ifdef INET6
			    + 1
#endif
			    )];
	struct uio opt;
	char *u_path, *u_hostname, *u_name;
#ifdef INET
	uint32_t ip4s;
	struct in_addr *u_ip4;
#endif
#ifdef INET6
	struct in6_addr *u_ip6;
#endif
	size_t tmplen;
	int error, enforce_statfs, fi;

	bzero(&optiov, sizeof(optiov));
	opt.uio_iov = optiov;
	opt.uio_iovcnt = 0;
	opt.uio_offset = -1;
	opt.uio_resid = -1;
	opt.uio_segflg = UIO_SYSSPACE;
	opt.uio_rw = UIO_READ;
	opt.uio_td = td;

	/* Set permissions for top-level jails from sysctls. */
	if (!jailed(td->td_ucred)) {
		for (fi = 0; fi < sizeof(pr_allow_names) /
		     sizeof(pr_allow_names[0]); fi++) {
			optiov[opt.uio_iovcnt].iov_base =
			    (jail_default_allow & (1 << fi))
			    ? pr_allow_names[fi] : pr_allow_nonames[fi];
			optiov[opt.uio_iovcnt].iov_len =
			    strlen(optiov[opt.uio_iovcnt].iov_base) + 1;
			opt.uio_iovcnt += 2;
		}
		optiov[opt.uio_iovcnt].iov_base = "enforce_statfs";
		optiov[opt.uio_iovcnt].iov_len = sizeof("enforce_statfs");
		opt.uio_iovcnt++;
		enforce_statfs = jail_default_enforce_statfs;
		optiov[opt.uio_iovcnt].iov_base = &enforce_statfs;
		optiov[opt.uio_iovcnt].iov_len = sizeof(enforce_statfs);
		opt.uio_iovcnt++;
	}

	tmplen = MAXPATHLEN + MAXHOSTNAMELEN + MAXHOSTNAMELEN;
#ifdef INET
	ip4s = (j->version == 0) ? 1 : j->ip4s;
	if (ip4s > jail_max_af_ips)
		return (EINVAL);
	tmplen += ip4s * sizeof(struct in_addr);
#else
	if (j->ip4s > 0)
		return (EINVAL);
#endif
#ifdef INET6
	if (j->ip6s > jail_max_af_ips)
		return (EINVAL);
	tmplen += j->ip6s * sizeof(struct in6_addr);
#else
	if (j->ip6s > 0)
		return (EINVAL);
#endif
	u_path = malloc(tmplen, M_TEMP, M_WAITOK);
	u_hostname = u_path + MAXPATHLEN;
	u_name = u_hostname + MAXHOSTNAMELEN;
#ifdef INET
	u_ip4 = (struct in_addr *)(u_name + MAXHOSTNAMELEN);
#endif
#ifdef INET6
#ifdef INET
	u_ip6 = (struct in6_addr *)(u_ip4 + ip4s);
#else
	u_ip6 = (struct in6_addr *)(u_name + MAXHOSTNAMELEN);
#endif
#endif
	optiov[opt.uio_iovcnt].iov_base = "path";
	optiov[opt.uio_iovcnt].iov_len = sizeof("path");
	opt.uio_iovcnt++;
	optiov[opt.uio_iovcnt].iov_base = u_path;
	error = copyinstr(j->path, u_path, MAXPATHLEN,
	    &optiov[opt.uio_iovcnt].iov_len);
	if (error) {
		free(u_path, M_TEMP);
		return (error);
	}
	opt.uio_iovcnt++;
	optiov[opt.uio_iovcnt].iov_base = "host.hostname";
	optiov[opt.uio_iovcnt].iov_len = sizeof("host.hostname");
	opt.uio_iovcnt++;
	optiov[opt.uio_iovcnt].iov_base = u_hostname;
	error = copyinstr(j->hostname, u_hostname, MAXHOSTNAMELEN,
	    &optiov[opt.uio_iovcnt].iov_len);
	if (error) {
		free(u_path, M_TEMP);
		return (error);
	}
	opt.uio_iovcnt++;
	if (j->jailname != NULL) {
		optiov[opt.uio_iovcnt].iov_base = "name";
		optiov[opt.uio_iovcnt].iov_len = sizeof("name");
		opt.uio_iovcnt++;
		optiov[opt.uio_iovcnt].iov_base = u_name;
		error = copyinstr(j->jailname, u_name, MAXHOSTNAMELEN,
		    &optiov[opt.uio_iovcnt].iov_len);
		if (error) {
			free(u_path, M_TEMP);
			return (error);
		}
		opt.uio_iovcnt++;
	}
#ifdef INET
	optiov[opt.uio_iovcnt].iov_base = "ip4.addr";
	optiov[opt.uio_iovcnt].iov_len = sizeof("ip4.addr");
	opt.uio_iovcnt++;
	optiov[opt.uio_iovcnt].iov_base = u_ip4;
	optiov[opt.uio_iovcnt].iov_len = ip4s * sizeof(struct in_addr);
	if (j->version == 0)
		u_ip4->s_addr = j->ip4s;
	else {
		error = copyin(j->ip4, u_ip4, optiov[opt.uio_iovcnt].iov_len);
		if (error) {
			free(u_path, M_TEMP);
			return (error);
		}
	}
	opt.uio_iovcnt++;
#endif
#ifdef INET6
	optiov[opt.uio_iovcnt].iov_base = "ip6.addr";
	optiov[opt.uio_iovcnt].iov_len = sizeof("ip6.addr");
	opt.uio_iovcnt++;
	optiov[opt.uio_iovcnt].iov_base = u_ip6;
	optiov[opt.uio_iovcnt].iov_len = j->ip6s * sizeof(struct in6_addr);
	error = copyin(j->ip6, u_ip6, optiov[opt.uio_iovcnt].iov_len);
	if (error) {
		free(u_path, M_TEMP);
		return (error);
	}
	opt.uio_iovcnt++;
#endif
	KASSERT(opt.uio_iovcnt <= sizeof(optiov) / sizeof(optiov[0]),
	    ("kern_jail: too many iovecs (%d)", opt.uio_iovcnt));
	error = kern_jail_set(td, &opt, JAIL_CREATE | JAIL_ATTACH);
	free(u_path, M_TEMP);
	return (error);
}


/*
 * struct jail_set_args {
 *	struct iovec *iovp;
 *	unsigned int iovcnt;
 *	int flags;
 * };
 */
int
jail_set(struct thread *td, struct jail_set_args *uap)
{
	struct uio *auio;
	int error;

	/* Check that we have an even number of iovecs. */
	if (uap->iovcnt & 1)
		return (EINVAL);

	error = copyinuio(uap->iovp, uap->iovcnt, &auio);
	if (error)
		return (error);
	error = kern_jail_set(td, auio, uap->flags);
	free(auio, M_IOV);
	return (error);
}

int
kern_jail_set(struct thread *td, struct uio *optuio, int flags)
{
	struct nameidata nd;
#ifdef INET
	struct in_addr *ip4;
#endif
#ifdef INET6
	struct in6_addr *ip6;
#endif
	struct vfsopt *opt;
	struct vfsoptlist *opts;
	struct prison *pr, *deadpr, *mypr, *ppr, *tpr;
	struct vnode *root;
	char *domain, *errmsg, *host, *name, *p, *path, *uuid;
#if defined(INET) || defined(INET6)
	void *op;
#endif
	unsigned long hid;
	size_t namelen, onamelen;
	int created, cuflags, descend, enforce, error, errmsg_len, errmsg_pos;
	int gotenforce, gothid, gotslevel, fi, jid, len;
	int slevel, vfslocked;
#if defined(INET) || defined(INET6)
	int ii, ij;
#endif
#ifdef INET
	int ip4s, ip4a, redo_ip4;
#endif
#ifdef INET6
	int ip6s, ip6a, redo_ip6;
#endif
	unsigned pr_flags, ch_flags;
	unsigned pr_allow, ch_allow, tallow;
	char numbuf[12];

	error = priv_check(td, PRIV_JAIL_SET);
	if (!error && (flags & JAIL_ATTACH))
		error = priv_check(td, PRIV_JAIL_ATTACH);
	if (error)
		return (error);
	mypr = ppr = td->td_ucred->cr_prison;
	if ((flags & JAIL_CREATE) && !(mypr->pr_allow & PR_ALLOW_JAILS))
		return (EPERM);
	if (flags & ~JAIL_SET_MASK)
		return (EINVAL);

	/*
	 * Check all the parameters before committing to anything.  Not all
	 * errors can be caught early, but we may as well try.  Also, this
	 * takes care of some expensive stuff (path lookup) before getting
	 * the allprison lock.
	 *
	 * XXX Jails are not filesystems, and jail parameters are not mount
	 *     options.  But it makes more sense to re-use the vfsopt code
	 *     than duplicate it under a different name.
	 */
	error = vfs_buildopts(optuio, &opts);
	if (error)
		return (error);
#ifdef INET
	ip4a = 0;
	ip4 = NULL;
#endif
#ifdef INET6
	ip6a = 0;
	ip6 = NULL;
#endif

#if defined(INET) || defined(INET6)
 again:
#endif
	error = vfs_copyopt(opts, "jid", &jid, sizeof(jid));
	if (error == ENOENT)
		jid = 0;
	else if (error != 0)
		goto done_free;

	error = vfs_copyopt(opts, "securelevel", &slevel, sizeof(slevel));
	if (error == ENOENT)
		gotslevel = 0;
	else if (error != 0)
		goto done_free;
	else
		gotslevel = 1;

	error = vfs_copyopt(opts, "enforce_statfs", &enforce, sizeof(enforce));
	gotenforce = (error == 0);
	if (gotenforce) {
		if (enforce < 0 || enforce > 2)
			return (EINVAL);
	} else if (error != ENOENT)
		goto done_free;

	pr_flags = ch_flags = 0;
	for (fi = 0; fi < sizeof(pr_flag_names) / sizeof(pr_flag_names[0]);
	    fi++) {
		if (pr_flag_names[fi] == NULL)
			continue;
		vfs_flagopt(opts, pr_flag_names[fi], &pr_flags, 1 << fi);
		vfs_flagopt(opts, pr_flag_nonames[fi], &ch_flags, 1 << fi);
	}
	ch_flags |= pr_flags;
	if ((flags & (JAIL_CREATE | JAIL_UPDATE | JAIL_ATTACH)) == JAIL_CREATE
	    && !(pr_flags & PR_PERSIST)) {
		error = EINVAL;
		vfs_opterror(opts, "new jail must persist or attach");
		goto done_errmsg;
	}
#ifdef VIMAGE
	if ((flags & JAIL_UPDATE) && (ch_flags & PR_VNET)) {
		error = EINVAL;
		vfs_opterror(opts, "vnet cannot be changed after creation");
		goto done_errmsg;
	}
#endif

	pr_allow = ch_allow = 0;
	for (fi = 0; fi < sizeof(pr_allow_names) / sizeof(pr_allow_names[0]);
	    fi++) {
		vfs_flagopt(opts, pr_allow_names[fi], &pr_allow, 1 << fi);
		vfs_flagopt(opts, pr_allow_nonames[fi], &ch_allow, 1 << fi);
	}
	ch_allow |= pr_allow;

	error = vfs_getopt(opts, "name", (void **)&name, &len);
	if (error == ENOENT)
		name = NULL;
	else if (error != 0)
		goto done_free;
	else {
		if (len == 0 || name[len - 1] != '\0') {
			error = EINVAL;
			goto done_free;
		}
		if (len > MAXHOSTNAMELEN) {
			error = ENAMETOOLONG;
			goto done_free;
		}
	}

	error = vfs_getopt(opts, "host.hostname", (void **)&host, &len);
	if (error == ENOENT)
		host = NULL;
	else if (error != 0)
		goto done_free;
	else {
		ch_flags |= PR_HOST;
		pr_flags |= PR_HOST;
		if (len == 0 || host[len - 1] != '\0') {
			error = EINVAL;
			goto done_free;
		}
		if (len > MAXHOSTNAMELEN) {
			error = ENAMETOOLONG;
			goto done_free;
		}
	}

	error = vfs_getopt(opts, "host.domainname", (void **)&domain, &len);
	if (error == ENOENT)
		domain = NULL;
	else if (error != 0)
		goto done_free;
	else {
		ch_flags |= PR_HOST;
		pr_flags |= PR_HOST;
		if (len == 0 || domain[len - 1] != '\0') {
			error = EINVAL;
			goto done_free;
		}
		if (len > MAXHOSTNAMELEN) {
			error = ENAMETOOLONG;
			goto done_free;
		}
	}

	error = vfs_getopt(opts, "host.hostuuid", (void **)&uuid, &len);
	if (error == ENOENT)
		uuid = NULL;
	else if (error != 0)
		goto done_free;
	else {
		ch_flags |= PR_HOST;
		pr_flags |= PR_HOST;
		if (len == 0 || uuid[len - 1] != '\0') {
			error = EINVAL;
			goto done_free;
		}
		if (len > HOSTUUIDLEN) {
			error = ENAMETOOLONG;
			goto done_free;
		}
	}

#ifdef COMPAT_IA32
	if (td->td_proc->p_sysent->sv_flags & SV_IA32) {
		uint32_t hid32;

		error = vfs_copyopt(opts, "host.hostid", &hid32, sizeof(hid32));
		hid = hid32;
	} else
#endif
		error = vfs_copyopt(opts, "host.hostid", &hid, sizeof(hid));
	if (error == ENOENT)
		gothid = 0;
	else if (error != 0)
		goto done_free;
	else {
		gothid = 1;
		ch_flags |= PR_HOST;
		pr_flags |= PR_HOST;
	}

	/* This might be the second time around for this option. */
#ifdef INET
	error = vfs_getopt(opts, "ip4.addr", &op, &ip4s);
	if (error == ENOENT)
		ip4s = -1;
	else if (error != 0)
		goto done_free;
	else if (ip4s & (sizeof(*ip4) - 1)) {
		error = EINVAL;
		goto done_free;
	} else {
		ch_flags |= PR_IP4_USER;
		pr_flags |= PR_IP4_USER;
		if (ip4s > 0) {
			ip4s /= sizeof(*ip4);
			if (ip4s > jail_max_af_ips) {
				error = EINVAL;
				vfs_opterror(opts, "too many IPv4 addresses");
				goto done_errmsg;
			}
			if (ip4a < ip4s) {
				ip4a = ip4s;
				free(ip4, M_PRISON);
				ip4 = NULL;
			}
			if (ip4 == NULL)
				ip4 = malloc(ip4a * sizeof(*ip4), M_PRISON,
				    M_WAITOK);
			bcopy(op, ip4, ip4s * sizeof(*ip4));
			/*
			 * IP addresses are all sorted but ip[0] to preserve
			 * the primary IP address as given from userland.
			 * This special IP is used for unbound outgoing
			 * connections as well for "loopback" traffic.
			 */
			if (ip4s > 1)
				qsort(ip4 + 1, ip4s - 1, sizeof(*ip4), qcmp_v4);
			/*
			 * Check for duplicate addresses and do some simple
			 * zero and broadcast checks. If users give other bogus
			 * addresses it is their problem.
			 *
			 * We do not have to care about byte order for these
			 * checks so we will do them in NBO.
			 */
			for (ii = 0; ii < ip4s; ii++) {
				if (ip4[ii].s_addr == INADDR_ANY ||
				    ip4[ii].s_addr == INADDR_BROADCAST) {
					error = EINVAL;
					goto done_free;
				}
				if ((ii+1) < ip4s &&
				    (ip4[0].s_addr == ip4[ii+1].s_addr ||
				     ip4[ii].s_addr == ip4[ii+1].s_addr)) {
					error = EINVAL;
					goto done_free;
				}
			}
		}
	}
#endif

#ifdef INET6
	error = vfs_getopt(opts, "ip6.addr", &op, &ip6s);
	if (error == ENOENT)
		ip6s = -1;
	else if (error != 0)
		goto done_free;
	else if (ip6s & (sizeof(*ip6) - 1)) {
		error = EINVAL;
		goto done_free;
	} else {
		ch_flags |= PR_IP6_USER;
		pr_flags |= PR_IP6_USER;
		if (ip6s > 0) {
			ip6s /= sizeof(*ip6);
			if (ip6s > jail_max_af_ips) {
				error = EINVAL;
				vfs_opterror(opts, "too many IPv6 addresses");
				goto done_errmsg;
			}
			if (ip6a < ip6s) {
				ip6a = ip6s;
				free(ip6, M_PRISON);
				ip6 = NULL;
			}
			if (ip6 == NULL)
				ip6 = malloc(ip6a * sizeof(*ip6), M_PRISON,
				    M_WAITOK);
			bcopy(op, ip6, ip6s * sizeof(*ip6));
			if (ip6s > 1)
				qsort(ip6 + 1, ip6s - 1, sizeof(*ip6), qcmp_v6);
			for (ii = 0; ii < ip6s; ii++) {
				if (IN6_IS_ADDR_UNSPECIFIED(&ip6[ii])) {
					error = EINVAL;
					goto done_free;
				}
				if ((ii+1) < ip6s &&
				    (IN6_ARE_ADDR_EQUAL(&ip6[0], &ip6[ii+1]) ||
				     IN6_ARE_ADDR_EQUAL(&ip6[ii], &ip6[ii+1])))
				{
					error = EINVAL;
					goto done_free;
				}
			}
		}
	}
#endif

	root = NULL;
	error = vfs_getopt(opts, "path", (void **)&path, &len);
	if (error == ENOENT)
		path = NULL;
	else if (error != 0)
		goto done_free;
	else {
		if (flags & JAIL_UPDATE) {
			error = EINVAL;
			vfs_opterror(opts,
			    "path cannot be changed after creation");
			goto done_errmsg;
		}
		if (len == 0 || path[len - 1] != '\0') {
			error = EINVAL;
			goto done_free;
		}
		if (len < 2 || (len == 2 && path[0] == '/'))
			path = NULL;
		else {
			/* Leave room for a real-root full pathname. */
			if (len + (path[0] == '/' && strcmp(mypr->pr_path, "/")
			    ? strlen(mypr->pr_path) : 0) > MAXPATHLEN) {
				error = ENAMETOOLONG;
				goto done_free;
			}
			NDINIT(&nd, LOOKUP, MPSAFE | FOLLOW, UIO_SYSSPACE,
			    path, td);
			error = namei(&nd);
			if (error)
				goto done_free;
			vfslocked = NDHASGIANT(&nd);
			root = nd.ni_vp;
			NDFREE(&nd, NDF_ONLY_PNBUF);
			if (root->v_type != VDIR) {
				error = ENOTDIR;
				vrele(root);
				VFS_UNLOCK_GIANT(vfslocked);
				goto done_free;
			}
			VFS_UNLOCK_GIANT(vfslocked);
		}
	}

	/*
	 * Grab the allprison lock before letting modules check their
	 * parameters.  Once we have it, do not let go so we'll have a
	 * consistent view of the OSD list.
	 */
	sx_xlock(&allprison_lock);
	error = osd_jail_call(NULL, PR_METHOD_CHECK, opts);
	if (error)
		goto done_unlock_list;

	/* By now, all parameters should have been noted. */
	TAILQ_FOREACH(opt, opts, link) {
		if (!opt->seen && strcmp(opt->name, "errmsg")) {
			error = EINVAL;
			vfs_opterror(opts, "unknown parameter: %s", opt->name);
			goto done_unlock_list;
		}
	}

	/*
	 * See if we are creating a new record or updating an existing one.
	 * This abuses the file error codes ENOENT and EEXIST.
	 */
	cuflags = flags & (JAIL_CREATE | JAIL_UPDATE);
	if (!cuflags) {
		error = EINVAL;
		vfs_opterror(opts, "no valid operation (create or update)");
		goto done_unlock_list;
	}
	pr = NULL;
	if (jid != 0) {
		/*
		 * See if a requested jid already exists.  There is an
		 * information leak here if the jid exists but is not within
		 * the caller's jail hierarchy.  Jail creators will get EEXIST
		 * even though they cannot see the jail, and CREATE | UPDATE
		 * will return ENOENT which is not normally a valid error.
		 */
		if (jid < 0) {
			error = EINVAL;
			vfs_opterror(opts, "negative jid");
			goto done_unlock_list;
		}
		pr = prison_find(jid);
		if (pr != NULL) {
			ppr = pr->pr_parent;
			/* Create: jid must not exist. */
			if (cuflags == JAIL_CREATE) {
				mtx_unlock(&pr->pr_mtx);
				error = EEXIST;
				vfs_opterror(opts, "jail %d already exists",
				    jid);
				goto done_unlock_list;
			}
			if (!prison_ischild(mypr, pr)) {
				mtx_unlock(&pr->pr_mtx);
				pr = NULL;
			} else if (pr->pr_uref == 0) {
				if (!(flags & JAIL_DYING)) {
					mtx_unlock(&pr->pr_mtx);
					error = ENOENT;
					vfs_opterror(opts, "jail %d is dying",
					    jid);
					goto done_unlock_list;
				} else if ((flags & JAIL_ATTACH) ||
				    (pr_flags & PR_PERSIST)) {
					/*
					 * A dying jail might be resurrected
					 * (via attach or persist), but first
					 * it must determine if another jail
					 * has claimed its name.  Accomplish
					 * this by implicitly re-setting the
					 * name.
					 */
					if (name == NULL)
						name = prison_name(mypr, pr);
				}
			}
		}
		if (pr == NULL) {
			/* Update: jid must exist. */
			if (cuflags == JAIL_UPDATE) {
				error = ENOENT;
				vfs_opterror(opts, "jail %d not found", jid);
				goto done_unlock_list;
			}
		}
	}
	/*
	 * If the caller provided a name, look for a jail by that name.
	 * This has different semantics for creates and updates keyed by jid
	 * (where the name must not already exist in a different jail),
	 * and updates keyed by the name itself (where the name must exist
	 * because that is the jail being updated).
	 */
	if (name != NULL) {
		p = strrchr(name, '.');
		if (p != NULL) {
			/*
			 * This is a hierarchical name.  Split it into the
			 * parent and child names, and make sure the parent
			 * exists or matches an already found jail.
			 */
			*p = '\0';
			if (pr != NULL) {
				if (strncmp(name, ppr->pr_name, p - name) ||
				    ppr->pr_name[p - name] != '\0') {
					mtx_unlock(&pr->pr_mtx);
					error = EINVAL;
					vfs_opterror(opts,
					    "cannot change jail's parent");
					goto done_unlock_list;
				}
			} else {
				ppr = prison_find_name(mypr, name);
				if (ppr == NULL) {
					error = ENOENT;
					vfs_opterror(opts,
					    "jail \"%s\" not found", name);
					goto done_unlock_list;
				}
				mtx_unlock(&ppr->pr_mtx);
			}
			name = p + 1;
		}
		if (name[0] != '\0') {
			namelen =
			    (ppr == &prison0) ? 0 : strlen(ppr->pr_name) + 1;
 name_again:
			deadpr = NULL;
			FOREACH_PRISON_CHILD(ppr, tpr) {
				if (tpr != pr && tpr->pr_ref > 0 &&
				    !strcmp(tpr->pr_name + namelen, name)) {
					if (pr == NULL &&
					    cuflags != JAIL_CREATE) {
						mtx_lock(&tpr->pr_mtx);
						if (tpr->pr_ref > 0) {
							/*
							 * Use this jail
							 * for updates.
							 */
							if (tpr->pr_uref > 0) {
								pr = tpr;
								break;
							}
							deadpr = tpr;
						}
						mtx_unlock(&tpr->pr_mtx);
					} else if (tpr->pr_uref > 0) {
						/*
						 * Create, or update(jid):
						 * name must not exist in an
						 * active sibling jail.
						 */
						error = EEXIST;
						if (pr != NULL)
							mtx_unlock(&pr->pr_mtx);
						vfs_opterror(opts,
						   "jail \"%s\" already exists",
						   name);
						goto done_unlock_list;
					}
				}
			}
			/* If no active jail is found, use a dying one. */
			if (deadpr != NULL && pr == NULL) {
				if (flags & JAIL_DYING) {
					mtx_lock(&deadpr->pr_mtx);
					if (deadpr->pr_ref == 0) {
						mtx_unlock(&deadpr->pr_mtx);
						goto name_again;
					}
					pr = deadpr;
				} else if (cuflags == JAIL_UPDATE) {
					error = ENOENT;
					vfs_opterror(opts,
					    "jail \"%s\" is dying", name);
					goto done_unlock_list;
				}
			}
			/* Update: name must exist if no jid. */
			else if (cuflags == JAIL_UPDATE && pr == NULL) {
				error = ENOENT;
				vfs_opterror(opts, "jail \"%s\" not found",
				    name);
				goto done_unlock_list;
			}
		}
	}
	/* Update: must provide a jid or name. */
	else if (cuflags == JAIL_UPDATE && pr == NULL) {
		error = ENOENT;
		vfs_opterror(opts, "update specified no jail");
		goto done_unlock_list;
	}

	/* If there's no prison to update, create a new one and link it in. */
	if (pr == NULL) {
		created = 1;
		mtx_lock(&ppr->pr_mtx);
		if (ppr->pr_ref == 0 || (ppr->pr_flags & PR_REMOVE)) {
			mtx_unlock(&ppr->pr_mtx);
			error = ENOENT;
			vfs_opterror(opts, "parent jail went away!");
			goto done_unlock_list;
		}
		ppr->pr_ref++;
		ppr->pr_uref++;
		mtx_unlock(&ppr->pr_mtx);
		pr = malloc(sizeof(*pr), M_PRISON, M_WAITOK | M_ZERO);
		if (jid == 0) {
			/* Find the next free jid. */
			jid = lastprid + 1;
 findnext:
			if (jid == JAIL_MAX)
				jid = 1;
			TAILQ_FOREACH(tpr, &allprison, pr_list) {
				if (tpr->pr_id < jid)
					continue;
				if (tpr->pr_id > jid || tpr->pr_ref == 0) {
					TAILQ_INSERT_BEFORE(tpr, pr, pr_list);
					break;
				}
				if (jid == lastprid) {
					error = EAGAIN;
					vfs_opterror(opts,
					    "no available jail IDs");
					free(pr, M_PRISON);
					prison_deref(ppr, PD_DEREF |
					    PD_DEUREF | PD_LIST_XLOCKED);
					goto done_releroot;
				}
				jid++;
				goto findnext;
			}
			lastprid = jid;
		} else {
			/*
			 * The jail already has a jid (that did not yet exist),
			 * so just find where to insert it.
			 */
			TAILQ_FOREACH(tpr, &allprison, pr_list)
				if (tpr->pr_id >= jid) {
					TAILQ_INSERT_BEFORE(tpr, pr, pr_list);
					break;
				}
		}
		if (tpr == NULL)
			TAILQ_INSERT_TAIL(&allprison, pr, pr_list);
		LIST_INSERT_HEAD(&ppr->pr_children, pr, pr_sibling);
		for (tpr = ppr; tpr != NULL; tpr = tpr->pr_parent)
			tpr->pr_prisoncount++;

		pr->pr_parent = ppr;
		pr->pr_id = jid;

		/* Set some default values, and inherit some from the parent. */
		if (name == NULL)
			name = "";
		if (host != NULL || domain != NULL || uuid != NULL || gothid) {
			if (host == NULL)
				host = ppr->pr_hostname;
			if (domain == NULL)
				domain = ppr->pr_domainname;
			if (uuid == NULL)
				uuid = ppr->pr_hostuuid;
			if (!gothid)
				hid = ppr->pr_hostid;
		}
		if (path == NULL) {
			path = "/";
			root = mypr->pr_root;
			vref(root);
		}
#ifdef INET
		pr->pr_flags |= ppr->pr_flags & PR_IP4;
		pr->pr_ip4s = ppr->pr_ip4s;
		if (ppr->pr_ip4 != NULL) {
			pr->pr_ip4 = malloc(pr->pr_ip4s *
			    sizeof(struct in_addr), M_PRISON, M_WAITOK);
			bcopy(ppr->pr_ip4, pr->pr_ip4,
			    pr->pr_ip4s * sizeof(*pr->pr_ip4));
		}
#endif
#ifdef INET6
		pr->pr_flags |= ppr->pr_flags & PR_IP6;
		pr->pr_ip6s = ppr->pr_ip6s;
		if (ppr->pr_ip6 != NULL) {
			pr->pr_ip6 = malloc(pr->pr_ip6s *
			    sizeof(struct in6_addr), M_PRISON, M_WAITOK);
			bcopy(ppr->pr_ip6, pr->pr_ip6,
			    pr->pr_ip6s * sizeof(*pr->pr_ip6));
		}
#endif
		pr->pr_securelevel = ppr->pr_securelevel;
		pr->pr_allow = JAIL_DEFAULT_ALLOW & ppr->pr_allow;
		pr->pr_enforce_statfs = ppr->pr_enforce_statfs;

		LIST_INIT(&pr->pr_children);
		mtx_init(&pr->pr_mtx, "jail mutex", NULL, MTX_DEF | MTX_DUPOK);

#ifdef VIMAGE
		/* Allocate a new vnet if specified. */
		pr->pr_vnet = (pr_flags & PR_VNET)
		    ? vnet_alloc() : ppr->pr_vnet;
#endif
		/*
		 * Allocate a dedicated cpuset for each jail.
		 * Unlike other initial settings, this may return an erorr.
		 */
		error = cpuset_create_root(ppr, &pr->pr_cpuset);
		if (error) {
			prison_deref(pr, PD_LIST_XLOCKED);
			goto done_releroot;
		}

		mtx_lock(&pr->pr_mtx);
		/*
		 * New prisons do not yet have a reference, because we do not
		 * want other to see the incomplete prison once the
		 * allprison_lock is downgraded.
		 */
	} else {
		created = 0;
		/*
		 * Grab a reference for existing prisons, to ensure they
		 * continue to exist for the duration of the call.
		 */
		pr->pr_ref++;
	}

	/* Do final error checking before setting anything. */
	if (gotslevel) {
		if (slevel < ppr->pr_securelevel) {
			error = EPERM;
			goto done_deref_locked;
		}
	}
	if (gotenforce) {
		if (enforce < ppr->pr_enforce_statfs) {
			error = EPERM;
			goto done_deref_locked;
		}
	}
#ifdef INET
	if (ch_flags & PR_IP4_USER) {
		if (ppr->pr_flags & PR_IP4) {
			if (!(pr_flags & PR_IP4_USER)) {
				/*
				 * Silently ignore attempts to make the IP
				 * addresses unrestricted when the parent is
				 * restricted; in other words, interpret
				 * "unrestricted" as "as unrestricted as
				 * possible".
				 */
				ip4s = ppr->pr_ip4s;
				if (ip4s == 0) {
					free(ip4, M_PRISON);
					ip4 = NULL;
				} else if (ip4s <= ip4a) {
					/* Inherit the parent's address(es). */
					bcopy(ppr->pr_ip4, ip4,
					    ip4s * sizeof(*ip4));
				} else {
					/*
					 * There's no room for the parent's
					 * address list.  Allocate some more.
					 */
					ip4a = ip4s;
					free(ip4, M_PRISON);
					ip4 = malloc(ip4a * sizeof(*ip4),
					    M_PRISON, M_NOWAIT);
					if (ip4 != NULL)
						bcopy(ppr->pr_ip4, ip4,
						    ip4s * sizeof(*ip4));
					else {
						/* Allocation failed without
						 * sleeping.  Unlocking the
						 * prison now will invalidate
						 * some checks and prematurely
						 * show an unfinished new jail.
						 * So let go of everything and
						 * start over.
						 */
						prison_deref(pr, created
						    ? PD_LOCKED |
						      PD_LIST_XLOCKED
						    : PD_DEREF | PD_LOCKED |
						      PD_LIST_XLOCKED);
						if (root != NULL) {
							vfslocked =
							    VFS_LOCK_GIANT(
							    root->v_mount);
							vrele(root);
							VFS_UNLOCK_GIANT(
							    vfslocked);
						}
						ip4 = malloc(ip4a *
						    sizeof(*ip4), M_PRISON,
						    M_WAITOK);
						goto again;
					}
				}
			} else if (ip4s > 0) {
				/*
				 * Make sure the new set of IP addresses is a
				 * subset of the parent's list.  Don't worry
				 * about the parent being unlocked, as any
				 * setting is done with allprison_lock held.
				 */
				for (ij = 0; ij < ppr->pr_ip4s; ij++)
					if (ip4[0].s_addr ==
					    ppr->pr_ip4[ij].s_addr)
						break;
				if (ij == ppr->pr_ip4s) {
					error = EPERM;
					goto done_deref_locked;
				}
				if (ip4s > 1) {
					for (ii = ij = 1; ii < ip4s; ii++) {
						if (ip4[ii].s_addr ==
						    ppr->pr_ip4[0].s_addr)
							continue;
						for (; ij < ppr->pr_ip4s; ij++)
						    if (ip4[ii].s_addr ==
							ppr->pr_ip4[ij].s_addr)
							    break;
						if (ij == ppr->pr_ip4s)
							break;
					}
					if (ij == ppr->pr_ip4s) {
						error = EPERM;
						goto done_deref_locked;
					}
				}
			}
		}
		if (ip4s > 0) {
			/*
			 * Check for conflicting IP addresses.  We permit them
			 * if there is no more than one IP on each jail.  If
			 * there is a duplicate on a jail with more than one
			 * IP stop checking and return error.
			 */
			FOREACH_PRISON_DESCENDANT(&prison0, tpr, descend) {
				if (tpr == pr || tpr->pr_uref == 0) {
					descend = 0;
					continue;
				}
				if (!(tpr->pr_flags & PR_IP4_USER))
					continue;
				descend = 0;
				if (tpr->pr_ip4 == NULL ||
				    (ip4s == 1 && tpr->pr_ip4s == 1))
					continue;
				for (ii = 0; ii < ip4s; ii++) {
					if (_prison_check_ip4(tpr,
					    &ip4[ii]) == 0) {
						error = EADDRINUSE;
						vfs_opterror(opts,
						    "IPv4 addresses clash");
						goto done_deref_locked;
					}
				}
			}
		}
	}
#endif
#ifdef INET6
	if (ch_flags & PR_IP6_USER) {
		if (ppr->pr_flags & PR_IP6) {
			if (!(pr_flags & PR_IP6_USER)) {
				/*
				 * Silently ignore attempts to make the IP
				 * addresses unrestricted when the parent is
				 * restricted.
				 */
				ip6s = ppr->pr_ip6s;
				if (ip6s == 0) {
					free(ip6, M_PRISON);
					ip6 = NULL;
				} else if (ip6s <= ip6a) {
					/* Inherit the parent's address(es). */
					bcopy(ppr->pr_ip6, ip6,
					    ip6s * sizeof(*ip6));
				} else {
					/*
					 * There's no room for the parent's
					 * address list.
					 */
					ip6a = ip6s;
					free(ip6, M_PRISON);
					ip6 = malloc(ip6a * sizeof(*ip6),
					    M_PRISON, M_NOWAIT);
					if (ip6 != NULL)
						bcopy(ppr->pr_ip6, ip6,
						    ip6s * sizeof(*ip6));
					else {
						prison_deref(pr, created
						    ? PD_LOCKED |
						      PD_LIST_XLOCKED
						    : PD_DEREF | PD_LOCKED |
						      PD_LIST_XLOCKED);
						if (root != NULL) {
							vfslocked =
							    VFS_LOCK_GIANT(
							    root->v_mount);
							vrele(root);
							VFS_UNLOCK_GIANT(
							    vfslocked);
						}
						ip6 = malloc(ip6a *
						    sizeof(*ip6), M_PRISON,
						    M_WAITOK);
						goto again;
					}
				}
			} else if (ip6s > 0) {
				/*
				 * Make sure the new set of IP addresses is a
				 * subset of the parent's list.
				 */
				for (ij = 0; ij < ppr->pr_ip6s; ij++)
					if (IN6_ARE_ADDR_EQUAL(&ip6[0],
					    &ppr->pr_ip6[ij]))
						break;
				if (ij == ppr->pr_ip6s) {
					error = EPERM;
					goto done_deref_locked;
				}
				if (ip6s > 1) {
					for (ii = ij = 1; ii < ip6s; ii++) {
						if (IN6_ARE_ADDR_EQUAL(&ip6[ii],
						    &ppr->pr_ip6[0]))
							continue;
						for (; ij < ppr->pr_ip6s; ij++)
							if (IN6_ARE_ADDR_EQUAL(
							    &ip6[ii],
							    &ppr->pr_ip6[ij]))
								break;
						if (ij == ppr->pr_ip6s)
							break;
					}
					if (ij == ppr->pr_ip6s) {
						error = EPERM;
						goto done_deref_locked;
					}
				}
			}
		}
		if (ip6s > 0) {
			/* Check for conflicting IP addresses. */
			FOREACH_PRISON_DESCENDANT(&prison0, tpr, descend) {
				if (tpr == pr || tpr->pr_uref == 0) {
					descend = 0;
					continue;
				}
				if (!(tpr->pr_flags & PR_IP6_USER))
					continue;
				descend = 0;
				if (tpr->pr_ip6 == NULL ||
				    (ip6s == 1 && tpr->pr_ip6s == 1))
					continue;
				for (ii = 0; ii < ip6s; ii++) {
					if (_prison_check_ip6(tpr,
					    &ip6[ii]) == 0) {
						error = EADDRINUSE;
						vfs_opterror(opts,
						    "IPv6 addresses clash");
						goto done_deref_locked;
					}
				}
			}
		}
	}
#endif
	onamelen = namelen = 0;
	if (name != NULL) {
		/* Give a default name of the jid. */
		if (name[0] == '\0')
			snprintf(name = numbuf, sizeof(numbuf), "%d", jid);
		else if (strtoul(name, &p, 10) != jid && *p == '\0') {
			error = EINVAL;
			vfs_opterror(opts, "name cannot be numeric");
			goto done_deref_locked;
		}
		/*
		 * Make sure the name isn't too long for the prison or its
		 * children.
		 */
		onamelen = strlen(pr->pr_name);
		namelen = strlen(name);
		if (strlen(ppr->pr_name) + namelen + 2 > sizeof(pr->pr_name)) {
			error = ENAMETOOLONG;
			goto done_deref_locked;
		}
		FOREACH_PRISON_DESCENDANT(pr, tpr, descend) {
			if (strlen(tpr->pr_name) + (namelen - onamelen) >=
			    sizeof(pr->pr_name)) {
				error = ENAMETOOLONG;
				goto done_deref_locked;
			}
		}
	}
	if (pr_allow & ~ppr->pr_allow) {
		error = EPERM;
		goto done_deref_locked;
	}

	/* Set the parameters of the prison. */
#ifdef INET
	redo_ip4 = 0;
	if (ch_flags & PR_IP4_USER) {
		if (pr_flags & PR_IP4_USER) {
			/* Some restriction set. */
			pr->pr_flags |= PR_IP4;
			if (ip4s >= 0) {
				free(pr->pr_ip4, M_PRISON);
				pr->pr_ip4s = ip4s;
				pr->pr_ip4 = ip4;
				ip4 = NULL;
			}
		} else if (ppr->pr_flags & PR_IP4) {
			/* This restriction cleared, but keep inherited. */
			free(pr->pr_ip4, M_PRISON);
			pr->pr_ip4s = ip4s;
			pr->pr_ip4 = ip4;
			ip4 = NULL;
		} else {
			/* Restriction cleared, now unrestricted. */
			pr->pr_flags &= ~PR_IP4;
			free(pr->pr_ip4, M_PRISON);
			pr->pr_ip4s = 0;
		}
		FOREACH_PRISON_DESCENDANT_LOCKED(pr, tpr, descend) {
			if (prison_restrict_ip4(tpr, NULL)) {
				redo_ip4 = 1;
				descend = 0;
			}
		}
	}
#endif
#ifdef INET6
	redo_ip6 = 0;
	if (ch_flags & PR_IP6_USER) {
		if (pr_flags & PR_IP6_USER) {
			/* Some restriction set. */
			pr->pr_flags |= PR_IP6;
			if (ip6s >= 0) {
				free(pr->pr_ip6, M_PRISON);
				pr->pr_ip6s = ip6s;
				pr->pr_ip6 = ip6;
				ip6 = NULL;
			}
		} else if (ppr->pr_flags & PR_IP6) {
			/* This restriction cleared, but keep inherited. */
			free(pr->pr_ip6, M_PRISON);
			pr->pr_ip6s = ip6s;
			pr->pr_ip6 = ip6;
			ip6 = NULL;
		} else {
			/* Restriction cleared, now unrestricted. */
			pr->pr_flags &= ~PR_IP6;
			free(pr->pr_ip6, M_PRISON);
			pr->pr_ip6s = 0;
		}
		FOREACH_PRISON_DESCENDANT_LOCKED(pr, tpr, descend) {
			if (prison_restrict_ip6(tpr, NULL)) {
				redo_ip6 = 1;
				descend = 0;
			}
		}
	}
#endif
	if (gotslevel) {
		pr->pr_securelevel = slevel;
		/* Set all child jails to be at least this level. */
		FOREACH_PRISON_DESCENDANT_LOCKED(pr, tpr, descend)
			if (tpr->pr_securelevel < slevel)
				tpr->pr_securelevel = slevel;
	}
	if (gotenforce) {
		pr->pr_enforce_statfs = enforce;
		/* Pass this restriction on to the children. */
		FOREACH_PRISON_DESCENDANT_LOCKED(pr, tpr, descend)
			if (tpr->pr_enforce_statfs < enforce)
				tpr->pr_enforce_statfs = enforce;
	}
	if (name != NULL) {
		if (ppr == &prison0)
			strlcpy(pr->pr_name, name, sizeof(pr->pr_name));
		else
			snprintf(pr->pr_name, sizeof(pr->pr_name), "%s.%s",
			    ppr->pr_name, name);
		/* Change this component of child names. */
		FOREACH_PRISON_DESCENDANT_LOCKED(pr, tpr, descend) {
			bcopy(tpr->pr_name + onamelen, tpr->pr_name + namelen,
			    strlen(tpr->pr_name + onamelen) + 1);
			bcopy(pr->pr_name, tpr->pr_name, namelen);
		}
	}
	if (path != NULL) {
		/* Try to keep a real-rooted full pathname. */
		if (path[0] == '/' && strcmp(mypr->pr_path, "/"))
			snprintf(pr->pr_path, sizeof(pr->pr_path), "%s%s",
			    mypr->pr_path, path);
		else
			strlcpy(pr->pr_path, path, sizeof(pr->pr_path));
		pr->pr_root = root;
	}
	if (PR_HOST & ch_flags & ~pr_flags) {
		if (pr->pr_flags & PR_HOST) {
			/*
			 * Copy the parent's host info.  As with pr_ip4 above,
			 * the lack of a lock on the parent is not a problem;
			 * it is always set with allprison_lock at least
			 * shared, and is held exclusively here.
			 */
			strlcpy(pr->pr_hostname, pr->pr_parent->pr_hostname,
			    sizeof(pr->pr_hostname));
			strlcpy(pr->pr_domainname, pr->pr_parent->pr_domainname,
			    sizeof(pr->pr_domainname));
			strlcpy(pr->pr_hostuuid, pr->pr_parent->pr_hostuuid,
			    sizeof(pr->pr_hostuuid));
			pr->pr_hostid = pr->pr_parent->pr_hostid;
		}
	} else if (host != NULL || domain != NULL || uuid != NULL || gothid) {
		/* Set this prison, and any descendants without PR_HOST. */
		if (host != NULL)
			strlcpy(pr->pr_hostname, host, sizeof(pr->pr_hostname));
		if (domain != NULL)
			strlcpy(pr->pr_domainname, domain,
			    sizeof(pr->pr_domainname));
		if (uuid != NULL)
			strlcpy(pr->pr_hostuuid, uuid, sizeof(pr->pr_hostuuid));
		if (gothid)
			pr->pr_hostid = hid;
		FOREACH_PRISON_DESCENDANT_LOCKED(pr, tpr, descend) {
			if (tpr->pr_flags & PR_HOST)
				descend = 0;
			else {
				if (host != NULL)
					strlcpy(tpr->pr_hostname,
					    pr->pr_hostname,
					    sizeof(tpr->pr_hostname));
				if (domain != NULL)
					strlcpy(tpr->pr_domainname,
					    pr->pr_domainname,
					    sizeof(tpr->pr_domainname));
				if (uuid != NULL)
					strlcpy(tpr->pr_hostuuid,
					    pr->pr_hostuuid,
					    sizeof(tpr->pr_hostuuid));
				if (gothid)
					tpr->pr_hostid = hid;
			}
		}
	}
	if ((tallow = ch_allow & ~pr_allow)) {
		/* Clear allow bits in all children. */
		FOREACH_PRISON_DESCENDANT_LOCKED(pr, tpr, descend)
			tpr->pr_allow &= ~tallow;
	}
	pr->pr_allow = (pr->pr_allow & ~ch_allow) | pr_allow;
	/*
	 * Persistent prisons get an extra reference, and prisons losing their
	 * persist flag lose that reference.  Only do this for existing prisons
	 * for now, so new ones will remain unseen until after the module
	 * handlers have completed.
	 */
	if (!created && (ch_flags & PR_PERSIST & (pr_flags ^ pr->pr_flags))) {
		if (pr_flags & PR_PERSIST) {
			pr->pr_ref++;
			pr->pr_uref++;
		} else {
			pr->pr_ref--;
			pr->pr_uref--;
		}
	}
	pr->pr_flags = (pr->pr_flags & ~ch_flags) | pr_flags;
	mtx_unlock(&pr->pr_mtx);

	/* Locks may have prevented a complete restriction of child IP
	 * addresses.  If so, allocate some more memory and try again.
	 */
#ifdef INET
	while (redo_ip4) {
		ip4s = pr->pr_ip4s;
		ip4 = malloc(ip4s * sizeof(*ip4), M_PRISON, M_WAITOK);
		mtx_lock(&pr->pr_mtx);
		redo_ip4 = 0;
		FOREACH_PRISON_DESCENDANT_LOCKED(pr, tpr, descend) {
			if (prison_restrict_ip4(tpr, ip4)) {
				if (ip4 != NULL)
					ip4 = NULL;
				else
					redo_ip4 = 1;
			}
		}
		mtx_unlock(&pr->pr_mtx);
	}
#endif
#ifdef INET6
	while (redo_ip6) {
		ip6s = pr->pr_ip6s;
		ip6 = malloc(ip6s * sizeof(*ip6), M_PRISON, M_WAITOK);
		mtx_lock(&pr->pr_mtx);
		redo_ip6 = 0;
		FOREACH_PRISON_DESCENDANT_LOCKED(pr, tpr, descend) {
			if (prison_restrict_ip6(tpr, ip6)) {
				if (ip6 != NULL)
					ip6 = NULL;
				else
					redo_ip6 = 1;
			}
		}
		mtx_unlock(&pr->pr_mtx);
	}
#endif

	/* Let the modules do their work. */
	sx_downgrade(&allprison_lock);
	if (created) {
		error = osd_jail_call(pr, PR_METHOD_CREATE, opts);
		if (error) {
			prison_deref(pr, PD_LIST_SLOCKED);
			goto done_errmsg;
		}
	}
	error = osd_jail_call(pr, PR_METHOD_SET, opts);
	if (error) {
		prison_deref(pr, created
		    ? PD_LIST_SLOCKED
		    : PD_DEREF | PD_LIST_SLOCKED);
		goto done_errmsg;
	}

	/* Attach this process to the prison if requested. */
	if (flags & JAIL_ATTACH) {
		mtx_lock(&pr->pr_mtx);
		error = do_jail_attach(td, pr);
		if (error) {
			vfs_opterror(opts, "attach failed");
			if (!created)
				prison_deref(pr, PD_DEREF);
			goto done_errmsg;
		}
	}

	/*
	 * Now that it is all there, drop the temporary reference from existing
	 * prisons.  Or add a reference to newly created persistent prisons
	 * (which was not done earlier so that the prison would not be publicly
	 * visible).
	 */
	if (!created) {
		prison_deref(pr, (flags & JAIL_ATTACH)
		    ? PD_DEREF
		    : PD_DEREF | PD_LIST_SLOCKED);
	} else {
		if (pr_flags & PR_PERSIST) {
			mtx_lock(&pr->pr_mtx);
			pr->pr_ref++;
			pr->pr_uref++;
			mtx_unlock(&pr->pr_mtx);
		}
		if (!(flags & JAIL_ATTACH))
			sx_sunlock(&allprison_lock);
	}
	td->td_retval[0] = pr->pr_id;
	goto done_errmsg;

 done_deref_locked:
	prison_deref(pr, created
	    ? PD_LOCKED | PD_LIST_XLOCKED
	    : PD_DEREF | PD_LOCKED | PD_LIST_XLOCKED);
	goto done_releroot;
 done_unlock_list:
	sx_xunlock(&allprison_lock);
 done_releroot:
	if (root != NULL) {
		vfslocked = VFS_LOCK_GIANT(root->v_mount);
		vrele(root);
		VFS_UNLOCK_GIANT(vfslocked);
	}
 done_errmsg:
	if (error) {
		vfs_getopt(opts, "errmsg", (void **)&errmsg, &errmsg_len);
		if (errmsg_len > 0) {
			errmsg_pos = 2 * vfs_getopt_pos(opts, "errmsg") + 1;
			if (errmsg_pos > 0) {
				if (optuio->uio_segflg == UIO_SYSSPACE)
					bcopy(errmsg,
					   optuio->uio_iov[errmsg_pos].iov_base,
					   errmsg_len);
				else
					copyout(errmsg,
					   optuio->uio_iov[errmsg_pos].iov_base,
					   errmsg_len);
			}
		}
	}
 done_free:
#ifdef INET
	free(ip4, M_PRISON);
#endif
#ifdef INET6
	free(ip6, M_PRISON);
#endif
	vfs_freeopts(opts);
	return (error);
}


/*
 * struct jail_get_args {
 *	struct iovec *iovp;
 *	unsigned int iovcnt;
 *	int flags;
 * };
 */
int
jail_get(struct thread *td, struct jail_get_args *uap)
{
	struct uio *auio;
	int error;

	/* Check that we have an even number of iovecs. */
	if (uap->iovcnt & 1)
		return (EINVAL);

	error = copyinuio(uap->iovp, uap->iovcnt, &auio);
	if (error)
		return (error);
	error = kern_jail_get(td, auio, uap->flags);
	if (error == 0)
		error = copyout(auio->uio_iov, uap->iovp,
		    uap->iovcnt * sizeof (struct iovec));
	free(auio, M_IOV);
	return (error);
}

int
kern_jail_get(struct thread *td, struct uio *optuio, int flags)
{
	struct prison *pr, *mypr;
	struct vfsopt *opt;
	struct vfsoptlist *opts;
	char *errmsg, *name;
	int error, errmsg_len, errmsg_pos, fi, i, jid, len, locked, pos;

	if (flags & ~JAIL_GET_MASK)
		return (EINVAL);

	/* Get the parameter list. */
	error = vfs_buildopts(optuio, &opts);
	if (error)
		return (error);
	errmsg_pos = vfs_getopt_pos(opts, "errmsg");
	mypr = td->td_ucred->cr_prison;

	/*
	 * Find the prison specified by one of: lastjid, jid, name.
	 */
	sx_slock(&allprison_lock);
	error = vfs_copyopt(opts, "lastjid", &jid, sizeof(jid));
	if (error == 0) {
		TAILQ_FOREACH(pr, &allprison, pr_list) {
			if (pr->pr_id > jid && prison_ischild(mypr, pr)) {
				mtx_lock(&pr->pr_mtx);
				if (pr->pr_ref > 0 &&
				    (pr->pr_uref > 0 || (flags & JAIL_DYING)))
					break;
				mtx_unlock(&pr->pr_mtx);
			}
		}
		if (pr != NULL)
			goto found_prison;
		error = ENOENT;
		vfs_opterror(opts, "no jail after %d", jid);
		goto done_unlock_list;
	} else if (error != ENOENT)
		goto done_unlock_list;

	error = vfs_copyopt(opts, "jid", &jid, sizeof(jid));
	if (error == 0) {
		if (jid != 0) {
			pr = prison_find_child(mypr, jid);
			if (pr != NULL) {
				if (pr->pr_uref == 0 && !(flags & JAIL_DYING)) {
					mtx_unlock(&pr->pr_mtx);
					error = ENOENT;
					vfs_opterror(opts, "jail %d is dying",
					    jid);
					goto done_unlock_list;
				}
				goto found_prison;
			}
			error = ENOENT;
			vfs_opterror(opts, "jail %d not found", jid);
			goto done_unlock_list;
		}
	} else if (error != ENOENT)
		goto done_unlock_list;

	error = vfs_getopt(opts, "name", (void **)&name, &len);
	if (error == 0) {
		if (len == 0 || name[len - 1] != '\0') {
			error = EINVAL;
			goto done_unlock_list;
		}
		pr = prison_find_name(mypr, name);
		if (pr != NULL) {
			if (pr->pr_uref == 0 && !(flags & JAIL_DYING)) {
				mtx_unlock(&pr->pr_mtx);
				error = ENOENT;
				vfs_opterror(opts, "jail \"%s\" is dying",
				    name);
				goto done_unlock_list;
			}
			goto found_prison;
		}
		error = ENOENT;
		vfs_opterror(opts, "jail \"%s\" not found", name);
		goto done_unlock_list;
	} else if (error != ENOENT)
		goto done_unlock_list;

	vfs_opterror(opts, "no jail specified");
	error = ENOENT;
	goto done_unlock_list;

 found_prison:
	/* Get the parameters of the prison. */
	pr->pr_ref++;
	locked = PD_LOCKED;
	td->td_retval[0] = pr->pr_id;
	error = vfs_setopt(opts, "jid", &pr->pr_id, sizeof(pr->pr_id));
	if (error != 0 && error != ENOENT)
		goto done_deref;
	i = (pr->pr_parent == mypr) ? 0 : pr->pr_parent->pr_id;
	error = vfs_setopt(opts, "parent", &i, sizeof(i));
	if (error != 0 && error != ENOENT)
		goto done_deref;
	error = vfs_setopts(opts, "name", prison_name(mypr, pr));
	if (error != 0 && error != ENOENT)
		goto done_deref;
	error = vfs_setopt(opts, "cpuset.id", &pr->pr_cpuset->cs_id,
	    sizeof(pr->pr_cpuset->cs_id));
	if (error != 0 && error != ENOENT)
		goto done_deref;
	error = vfs_setopts(opts, "path", prison_path(mypr, pr));
	if (error != 0 && error != ENOENT)
		goto done_deref;
#ifdef INET
	error = vfs_setopt_part(opts, "ip4.addr", pr->pr_ip4,
	    pr->pr_ip4s * sizeof(*pr->pr_ip4));
	if (error != 0 && error != ENOENT)
		goto done_deref;
#endif
#ifdef INET6
	error = vfs_setopt_part(opts, "ip6.addr", pr->pr_ip6,
	    pr->pr_ip6s * sizeof(*pr->pr_ip6));
	if (error != 0 && error != ENOENT)
		goto done_deref;
#endif
	error = vfs_setopt(opts, "securelevel", &pr->pr_securelevel,
	    sizeof(pr->pr_securelevel));
	if (error != 0 && error != ENOENT)
		goto done_deref;
	error = vfs_setopts(opts, "host.hostname", pr->pr_hostname);
	if (error != 0 && error != ENOENT)
		goto done_deref;
	error = vfs_setopts(opts, "host.domainname", pr->pr_domainname);
	if (error != 0 && error != ENOENT)
		goto done_deref;
	error = vfs_setopts(opts, "host.hostuuid", pr->pr_hostuuid);
	if (error != 0 && error != ENOENT)
		goto done_deref;
#ifdef COMPAT_IA32
	if (td->td_proc->p_sysent->sv_flags & SV_IA32) {
		uint32_t hid32 = pr->pr_hostid;

		error = vfs_setopt(opts, "host.hostid", &hid32, sizeof(hid32));
	} else
#endif
	error = vfs_setopt(opts, "host.hostid", &pr->pr_hostid,
	    sizeof(pr->pr_hostid));
	if (error != 0 && error != ENOENT)
		goto done_deref;
	error = vfs_setopt(opts, "enforce_statfs", &pr->pr_enforce_statfs,
	    sizeof(pr->pr_enforce_statfs));
	if (error != 0 && error != ENOENT)
		goto done_deref;
	for (fi = 0; fi < sizeof(pr_flag_names) / sizeof(pr_flag_names[0]);
	    fi++) {
		if (pr_flag_names[fi] == NULL)
			continue;
		i = (pr->pr_flags & (1 << fi)) ? 1 : 0;
		error = vfs_setopt(opts, pr_flag_names[fi], &i, sizeof(i));
		if (error != 0 && error != ENOENT)
			goto done_deref;
		i = !i;
		error = vfs_setopt(opts, pr_flag_nonames[fi], &i, sizeof(i));
		if (error != 0 && error != ENOENT)
			goto done_deref;
	}
	for (fi = 0; fi < sizeof(pr_allow_names) / sizeof(pr_allow_names[0]);
	    fi++) {
		if (pr_allow_names[fi] == NULL)
			continue;
		i = (pr->pr_allow & (1 << fi)) ? 1 : 0;
		error = vfs_setopt(opts, pr_allow_names[fi], &i, sizeof(i));
		if (error != 0 && error != ENOENT)
			goto done_deref;
		i = !i;
		error = vfs_setopt(opts, pr_allow_nonames[fi], &i, sizeof(i));
		if (error != 0 && error != ENOENT)
			goto done_deref;
	}
	i = (pr->pr_uref == 0);
	error = vfs_setopt(opts, "dying", &i, sizeof(i));
	if (error != 0 && error != ENOENT)
		goto done_deref;
	i = !i;
	error = vfs_setopt(opts, "nodying", &i, sizeof(i));
	if (error != 0 && error != ENOENT)
		goto done_deref;

	/* Get the module parameters. */
	mtx_unlock(&pr->pr_mtx);
	locked = 0;
	error = osd_jail_call(pr, PR_METHOD_GET, opts);
	if (error)
		goto done_deref;
	prison_deref(pr, PD_DEREF | PD_LIST_SLOCKED);

	/* By now, all parameters should have been noted. */
	TAILQ_FOREACH(opt, opts, link) {
		if (!opt->seen && strcmp(opt->name, "errmsg")) {
			error = EINVAL;
			vfs_opterror(opts, "unknown parameter: %s", opt->name);
			goto done_errmsg;
		}
	}

	/* Write the fetched parameters back to userspace. */
	error = 0;
	TAILQ_FOREACH(opt, opts, link) {
		if (opt->pos >= 0 && opt->pos != errmsg_pos) {
			pos = 2 * opt->pos + 1;
			optuio->uio_iov[pos].iov_len = opt->len;
			if (opt->value != NULL) {
				if (optuio->uio_segflg == UIO_SYSSPACE) {
					bcopy(opt->value,
					    optuio->uio_iov[pos].iov_base,
					    opt->len);
				} else {
					error = copyout(opt->value,
					    optuio->uio_iov[pos].iov_base,
					    opt->len);
					if (error)
						break;
				}
			}
		}
	}
	goto done_errmsg;

 done_deref:
	prison_deref(pr, locked | PD_DEREF | PD_LIST_SLOCKED);
	goto done_errmsg;

 done_unlock_list:
	sx_sunlock(&allprison_lock);
 done_errmsg:
	if (error && errmsg_pos >= 0) {
		vfs_getopt(opts, "errmsg", (void **)&errmsg, &errmsg_len);
		errmsg_pos = 2 * errmsg_pos + 1;
		if (errmsg_len > 0) {
			if (optuio->uio_segflg == UIO_SYSSPACE)
				bcopy(errmsg,
				    optuio->uio_iov[errmsg_pos].iov_base,
				    errmsg_len);
			else
				copyout(errmsg,
				    optuio->uio_iov[errmsg_pos].iov_base,
				    errmsg_len);
		}
	}
	vfs_freeopts(opts);
	return (error);
}


/*
 * struct jail_remove_args {
 *	int jid;
 * };
 */
int
jail_remove(struct thread *td, struct jail_remove_args *uap)
{
	struct prison *pr, *cpr, *lpr, *tpr;
	int descend, error;

	error = priv_check(td, PRIV_JAIL_REMOVE);
	if (error)
		return (error);

	sx_xlock(&allprison_lock);
	pr = prison_find_child(td->td_ucred->cr_prison, uap->jid);
	if (pr == NULL) {
		sx_xunlock(&allprison_lock);
		return (EINVAL);
	}

	/* Remove all descendants of this prison, then remove this prison. */
	pr->pr_ref++;
	pr->pr_flags |= PR_REMOVE;
	if (!LIST_EMPTY(&pr->pr_children)) {
		mtx_unlock(&pr->pr_mtx);
		lpr = NULL;
		FOREACH_PRISON_DESCENDANT(pr, cpr, descend) {
			mtx_lock(&cpr->pr_mtx);
			if (cpr->pr_ref > 0) {
				tpr = cpr;
				cpr->pr_ref++;
				cpr->pr_flags |= PR_REMOVE;
			} else {
				/* Already removed - do not do it again. */
				tpr = NULL;
			}
			mtx_unlock(&cpr->pr_mtx);
			if (lpr != NULL) {
				mtx_lock(&lpr->pr_mtx);
				prison_remove_one(lpr);
				sx_xlock(&allprison_lock);
			}
			lpr = tpr;
		}
		if (lpr != NULL) {
			mtx_lock(&lpr->pr_mtx);
			prison_remove_one(lpr);
			sx_xlock(&allprison_lock);
		}
		mtx_lock(&pr->pr_mtx);
	}
	prison_remove_one(pr);
	return (0);
}

static void
prison_remove_one(struct prison *pr)
{
	struct proc *p;
	int deuref;

	/* If the prison was persistent, it is not anymore. */
	deuref = 0;
	if (pr->pr_flags & PR_PERSIST) {
		pr->pr_ref--;
		deuref = PD_DEUREF;
		pr->pr_flags &= ~PR_PERSIST;
	}

	/*
	 * jail_remove added a reference.  If that's the only one, remove
	 * the prison now.
	 */
	KASSERT(pr->pr_ref > 0,
	    ("prison_remove_one removing a dead prison (jid=%d)", pr->pr_id));
	if (pr->pr_ref == 1) {
		prison_deref(pr,
		    deuref | PD_DEREF | PD_LOCKED | PD_LIST_XLOCKED);
		return;
	}

	mtx_unlock(&pr->pr_mtx);
	sx_xunlock(&allprison_lock);
	/*
	 * Kill all processes unfortunate enough to be attached to this prison.
	 */
	sx_slock(&allproc_lock);
	LIST_FOREACH(p, &allproc, p_list) {
		PROC_LOCK(p);
		if (p->p_state != PRS_NEW && p->p_ucred &&
		    p->p_ucred->cr_prison == pr)
			psignal(p, SIGKILL);
		PROC_UNLOCK(p);
	}
	sx_sunlock(&allproc_lock);
	/* Remove the temporary reference added by jail_remove. */
	prison_deref(pr, deuref | PD_DEREF);
}


/*
 * struct jail_attach_args {
 *	int jid;
 * };
 */
int
jail_attach(struct thread *td, struct jail_attach_args *uap)
{
	struct prison *pr;
	int error;

	error = priv_check(td, PRIV_JAIL_ATTACH);
	if (error)
		return (error);

	sx_slock(&allprison_lock);
	pr = prison_find_child(td->td_ucred->cr_prison, uap->jid);
	if (pr == NULL) {
		sx_sunlock(&allprison_lock);
		return (EINVAL);
	}

	/*
	 * Do not allow a process to attach to a prison that is not
	 * considered to be "alive".
	 */
	if (pr->pr_uref == 0) {
		mtx_unlock(&pr->pr_mtx);
		sx_sunlock(&allprison_lock);
		return (EINVAL);
	}

	return (do_jail_attach(td, pr));
}

static int
do_jail_attach(struct thread *td, struct prison *pr)
{
	struct prison *ppr;
	struct proc *p;
	struct ucred *newcred, *oldcred;
	int vfslocked, error;

	/*
	 * XXX: Note that there is a slight race here if two threads
	 * in the same privileged process attempt to attach to two
	 * different jails at the same time.  It is important for
	 * user processes not to do this, or they might end up with
	 * a process root from one prison, but attached to the jail
	 * of another.
	 */
	pr->pr_ref++;
	pr->pr_uref++;
	mtx_unlock(&pr->pr_mtx);

	/* Let modules do whatever they need to prepare for attaching. */
	error = osd_jail_call(pr, PR_METHOD_ATTACH, td);
	if (error) {
		prison_deref(pr, PD_DEREF | PD_DEUREF | PD_LIST_SLOCKED);
		return (error);
	}
	sx_sunlock(&allprison_lock);

	/*
	 * Reparent the newly attached process to this jail.
	 */
	ppr = td->td_ucred->cr_prison;
	p = td->td_proc;
	error = cpuset_setproc_update_set(p, pr->pr_cpuset);
	if (error)
		goto e_revert_osd;

	vfslocked = VFS_LOCK_GIANT(pr->pr_root->v_mount);
	vn_lock(pr->pr_root, LK_EXCLUSIVE | LK_RETRY);
	if ((error = change_dir(pr->pr_root, td)) != 0)
		goto e_unlock;
#ifdef MAC
	if ((error = mac_vnode_check_chroot(td->td_ucred, pr->pr_root)))
		goto e_unlock;
#endif
	VOP_UNLOCK(pr->pr_root, 0);
	if ((error = change_root(pr->pr_root, td)))
		goto e_unlock_giant;
	VFS_UNLOCK_GIANT(vfslocked);

	newcred = crget();
	PROC_LOCK(p);
	oldcred = p->p_ucred;
	setsugid(p);
	crcopy(newcred, oldcred);
	newcred->cr_prison = pr;
	p->p_ucred = newcred;
	PROC_UNLOCK(p);
	crfree(oldcred);
	prison_deref(ppr, PD_DEREF | PD_DEUREF);
	return (0);
 e_unlock:
	VOP_UNLOCK(pr->pr_root, 0);
 e_unlock_giant:
	VFS_UNLOCK_GIANT(vfslocked);
 e_revert_osd:
	/* Tell modules this thread is still in its old jail after all. */
	(void)osd_jail_call(ppr, PR_METHOD_ATTACH, td);
	prison_deref(pr, PD_DEREF | PD_DEUREF);
	return (error);
}


/*
 * Returns a locked prison instance, or NULL on failure.
 */
struct prison *
prison_find(int prid)
{
	struct prison *pr;

	sx_assert(&allprison_lock, SX_LOCKED);
	TAILQ_FOREACH(pr, &allprison, pr_list) {
		if (pr->pr_id == prid) {
			mtx_lock(&pr->pr_mtx);
			if (pr->pr_ref > 0)
				return (pr);
			mtx_unlock(&pr->pr_mtx);
		}
	}
	return (NULL);
}

/*
 * Find a prison that is a descendant of mypr.  Returns a locked prison or NULL.
 */
struct prison *
prison_find_child(struct prison *mypr, int prid)
{
	struct prison *pr;
	int descend;

	sx_assert(&allprison_lock, SX_LOCKED);
	FOREACH_PRISON_DESCENDANT(mypr, pr, descend) {
		if (pr->pr_id == prid) {
			mtx_lock(&pr->pr_mtx);
			if (pr->pr_ref > 0)
				return (pr);
			mtx_unlock(&pr->pr_mtx);
		}
	}
	return (NULL);
}

/*
 * Look for the name relative to mypr.  Returns a locked prison or NULL.
 */
struct prison *
prison_find_name(struct prison *mypr, const char *name)
{
	struct prison *pr, *deadpr;
	size_t mylen;
	int descend;

	sx_assert(&allprison_lock, SX_LOCKED);
	mylen = (mypr == &prison0) ? 0 : strlen(mypr->pr_name) + 1;
 again:
	deadpr = NULL;
	FOREACH_PRISON_DESCENDANT(mypr, pr, descend) {
		if (!strcmp(pr->pr_name + mylen, name)) {
			mtx_lock(&pr->pr_mtx);
			if (pr->pr_ref > 0) {
				if (pr->pr_uref > 0)
					return (pr);
				deadpr = pr;
			}
			mtx_unlock(&pr->pr_mtx);
		}
	}
	/* There was no valid prison - perhaps there was a dying one. */
	if (deadpr != NULL) {
		mtx_lock(&deadpr->pr_mtx);
		if (deadpr->pr_ref == 0) {
			mtx_unlock(&deadpr->pr_mtx);
			goto again;
		}
	}
	return (deadpr);
}

/*
 * See if a prison has the specific flag set.
 */
int
prison_flag(struct ucred *cred, unsigned flag)
{

	/* This is an atomic read, so no locking is necessary. */
	return (cred->cr_prison->pr_flags & flag);
}

int
prison_allow(struct ucred *cred, unsigned flag)
{

	/* This is an atomic read, so no locking is necessary. */
	return (cred->cr_prison->pr_allow & flag);
}

/*
 * Remove a prison reference.  If that was the last reference, remove the
 * prison itself - but not in this context in case there are locks held.
 */
void
prison_free_locked(struct prison *pr)
{

	mtx_assert(&pr->pr_mtx, MA_OWNED);
	pr->pr_ref--;
	if (pr->pr_ref == 0) {
		mtx_unlock(&pr->pr_mtx);
		TASK_INIT(&pr->pr_task, 0, prison_complete, pr);
		taskqueue_enqueue(taskqueue_thread, &pr->pr_task);
		return;
	}
	mtx_unlock(&pr->pr_mtx);
}

void
prison_free(struct prison *pr)
{

	mtx_lock(&pr->pr_mtx);
	prison_free_locked(pr);
}

static void
prison_complete(void *context, int pending)
{

	prison_deref((struct prison *)context, 0);
}

/*
 * Remove a prison reference (usually).  This internal version assumes no
 * mutexes are held, except perhaps the prison itself.  If there are no more
 * references, release and delist the prison.  On completion, the prison lock
 * and the allprison lock are both unlocked.
 */
static void
prison_deref(struct prison *pr, int flags)
{
	struct prison *ppr, *tpr;
	int vfslocked;

	if (!(flags & PD_LOCKED))
		mtx_lock(&pr->pr_mtx);
	/* Decrement the user references in a separate loop. */
	if (flags & PD_DEUREF) {
		for (tpr = pr;; tpr = tpr->pr_parent) {
			if (tpr != pr)
				mtx_lock(&tpr->pr_mtx);
			if (--tpr->pr_uref > 0)
				break;
			KASSERT(tpr != &prison0, ("prison0 pr_uref=0"));
			mtx_unlock(&tpr->pr_mtx);
		}
		/* Done if there were only user references to remove. */
		if (!(flags & PD_DEREF)) {
			mtx_unlock(&tpr->pr_mtx);
			if (flags & PD_LIST_SLOCKED)
				sx_sunlock(&allprison_lock);
			else if (flags & PD_LIST_XLOCKED)
				sx_xunlock(&allprison_lock);
			return;
		}
		if (tpr != pr) {
			mtx_unlock(&tpr->pr_mtx);
			mtx_lock(&pr->pr_mtx);
		}
	}

	for (;;) {
		if (flags & PD_DEREF)
			pr->pr_ref--;
		/* If the prison still has references, nothing else to do. */
		if (pr->pr_ref > 0) {
			mtx_unlock(&pr->pr_mtx);
			if (flags & PD_LIST_SLOCKED)
				sx_sunlock(&allprison_lock);
			else if (flags & PD_LIST_XLOCKED)
				sx_xunlock(&allprison_lock);
			return;
		}

		mtx_unlock(&pr->pr_mtx);
		if (flags & PD_LIST_SLOCKED) {
			if (!sx_try_upgrade(&allprison_lock)) {
				sx_sunlock(&allprison_lock);
				sx_xlock(&allprison_lock);
			}
		} else if (!(flags & PD_LIST_XLOCKED))
			sx_xlock(&allprison_lock);

		TAILQ_REMOVE(&allprison, pr, pr_list);
		LIST_REMOVE(pr, pr_sibling);
		ppr = pr->pr_parent;
		for (tpr = ppr; tpr != NULL; tpr = tpr->pr_parent)
			tpr->pr_prisoncount--;
		sx_downgrade(&allprison_lock);

#ifdef VIMAGE
		if (pr->pr_flags & PR_VNET)
			vnet_destroy(pr->pr_vnet);
#endif
		if (pr->pr_root != NULL) {
			vfslocked = VFS_LOCK_GIANT(pr->pr_root->v_mount);
			vrele(pr->pr_root);
			VFS_UNLOCK_GIANT(vfslocked);
		}
		mtx_destroy(&pr->pr_mtx);
#ifdef INET
		free(pr->pr_ip4, M_PRISON);
#endif
#ifdef INET6
		free(pr->pr_ip6, M_PRISON);
#endif
		if (pr->pr_cpuset != NULL)
			cpuset_rel(pr->pr_cpuset);
		osd_jail_exit(pr);
		free(pr, M_PRISON);

		/* Removing a prison frees a reference on its parent. */
		pr = ppr;
		mtx_lock(&pr->pr_mtx);
		flags = PD_DEREF | PD_LIST_SLOCKED;
	}
}

void
prison_hold_locked(struct prison *pr)
{

	mtx_assert(&pr->pr_mtx, MA_OWNED);
	KASSERT(pr->pr_ref > 0,
	    ("Trying to hold dead prison (jid=%d).", pr->pr_id));
	pr->pr_ref++;
}

void
prison_hold(struct prison *pr)
{

	mtx_lock(&pr->pr_mtx);
	prison_hold_locked(pr);
	mtx_unlock(&pr->pr_mtx);
}

void
prison_proc_hold(struct prison *pr)
{

	mtx_lock(&pr->pr_mtx);
	KASSERT(pr->pr_uref > 0,
	    ("Cannot add a process to a non-alive prison (jid=%d)", pr->pr_id));
	pr->pr_uref++;
	mtx_unlock(&pr->pr_mtx);
}

void
prison_proc_free(struct prison *pr)
{

	mtx_lock(&pr->pr_mtx);
	KASSERT(pr->pr_uref > 0,
	    ("Trying to kill a process in a dead prison (jid=%d)", pr->pr_id));
	prison_deref(pr, PD_DEUREF | PD_LOCKED);
}


#ifdef INET
/*
 * Restrict a prison's IP address list with its parent's, possibly replacing
 * it.  Return true if the replacement buffer was used (or would have been).
 */
static int
prison_restrict_ip4(struct prison *pr, struct in_addr *newip4)
{
	int ii, ij, used;
	struct prison *ppr;

	ppr = pr->pr_parent;
	if (!(pr->pr_flags & PR_IP4_USER)) {
		/* This has no user settings, so just copy the parent's list. */
		if (pr->pr_ip4s < ppr->pr_ip4s) {
			/*
			 * There's no room for the parent's list.  Use the
			 * new list buffer, which is assumed to be big enough
			 * (if it was passed).  If there's no buffer, try to
			 * allocate one.
			 */
			used = 1;
			if (newip4 == NULL) {
				newip4 = malloc(ppr->pr_ip4s * sizeof(*newip4),
				    M_PRISON, M_NOWAIT);
				if (newip4 != NULL)
					used = 0;
			}
			if (newip4 != NULL) {
				bcopy(ppr->pr_ip4, newip4,
				    ppr->pr_ip4s * sizeof(*newip4));
				free(pr->pr_ip4, M_PRISON);
				pr->pr_ip4 = newip4;
				pr->pr_ip4s = ppr->pr_ip4s;
				pr->pr_flags |= PR_IP4;
			}
			return (used);
		}
		pr->pr_ip4s = ppr->pr_ip4s;
		if (pr->pr_ip4s > 0)
			bcopy(ppr->pr_ip4, pr->pr_ip4,
			    pr->pr_ip4s * sizeof(*newip4));
		else if (pr->pr_ip4 != NULL) {
			free(pr->pr_ip4, M_PRISON);
			pr->pr_ip4 = NULL;
		}
		pr->pr_flags =
			(pr->pr_flags & ~PR_IP4) | (ppr->pr_flags & PR_IP4);
	} else if (pr->pr_ip4s > 0 && (ppr->pr_flags & PR_IP4)) {
		/* Remove addresses that aren't in the parent. */
		for (ij = 0; ij < ppr->pr_ip4s; ij++)
			if (pr->pr_ip4[0].s_addr == ppr->pr_ip4[ij].s_addr)
				break;
		if (ij < ppr->pr_ip4s)
			ii = 1;
		else {
			bcopy(pr->pr_ip4 + 1, pr->pr_ip4,
			    --pr->pr_ip4s * sizeof(*pr->pr_ip4));
			ii = 0;
		}
		for (ij = 1; ii < pr->pr_ip4s; ) {
			if (pr->pr_ip4[ii].s_addr == ppr->pr_ip4[0].s_addr) {
				ii++;
				continue;
			}
			switch (ij >= ppr->pr_ip4s ? -1 :
				qcmp_v4(&pr->pr_ip4[ii], &ppr->pr_ip4[ij])) {
			case -1:
				bcopy(pr->pr_ip4 + ii + 1, pr->pr_ip4 + ii,
				    (--pr->pr_ip4s - ii) * sizeof(*pr->pr_ip4));
				break;
			case 0:
				ii++;
				ij++;
				break;
			case 1:
				ij++;
				break;
			}
		}
		if (pr->pr_ip4s == 0) {
			free(pr->pr_ip4, M_PRISON);
			pr->pr_ip4 = NULL;
		}
	}
	return (0);
}

/*
 * Pass back primary IPv4 address of this jail.
 *
 * If not restricted return success but do not alter the address.  Caller has
 * to make sure to initialize it correctly (e.g. INADDR_ANY).
 *
 * Returns 0 on success, EAFNOSUPPORT if the jail doesn't allow IPv4.
 * Address returned in NBO.
 */
int
prison_get_ip4(struct ucred *cred, struct in_addr *ia)
{
	struct prison *pr;

	KASSERT(cred != NULL, ("%s: cred is NULL", __func__));
	KASSERT(ia != NULL, ("%s: ia is NULL", __func__));

	pr = cred->cr_prison;
	if (!(pr->pr_flags & PR_IP4))
		return (0);
	mtx_lock(&pr->pr_mtx);
	if (!(pr->pr_flags & PR_IP4)) {
		mtx_unlock(&pr->pr_mtx);
		return (0);
	}
	if (pr->pr_ip4 == NULL) {
		mtx_unlock(&pr->pr_mtx);
		return (EAFNOSUPPORT);
	}

	ia->s_addr = pr->pr_ip4[0].s_addr;
	mtx_unlock(&pr->pr_mtx);
	return (0);
}

/*
 * Return true if pr1 and pr2 have the same IPv4 address restrictions.
 */
int
prison_equal_ip4(struct prison *pr1, struct prison *pr2)
{

	if (pr1 == pr2)
		return (1);

	/*
	 * jail_set maintains an exclusive hold on allprison_lock while it
	 * changes the IP addresses, so only a shared hold is needed.  This is
	 * easier than locking the two prisons which would require finding the
	 * proper locking order and end up needing allprison_lock anyway.
	 */
	sx_slock(&allprison_lock);
	while (pr1 != &prison0 && !(pr1->pr_flags & PR_IP4_USER))
		pr1 = pr1->pr_parent;
	while (pr2 != &prison0 && !(pr2->pr_flags & PR_IP4_USER))
		pr2 = pr2->pr_parent;
	sx_sunlock(&allprison_lock);
	return (pr1 == pr2);
}

/*
 * Make sure our (source) address is set to something meaningful to this
 * jail.
 *
 * Returns 0 if jail doesn't restrict IPv4 or if address belongs to jail,
 * EADDRNOTAVAIL if the address doesn't belong, or EAFNOSUPPORT if the jail
 * doesn't allow IPv4.  Address passed in in NBO and returned in NBO.
 */
int
prison_local_ip4(struct ucred *cred, struct in_addr *ia)
{
	struct prison *pr;
	struct in_addr ia0;
	int error;

	KASSERT(cred != NULL, ("%s: cred is NULL", __func__));
	KASSERT(ia != NULL, ("%s: ia is NULL", __func__));

	pr = cred->cr_prison;
	if (!(pr->pr_flags & PR_IP4))
		return (0);
	mtx_lock(&pr->pr_mtx);
	if (!(pr->pr_flags & PR_IP4)) {
		mtx_unlock(&pr->pr_mtx);
		return (0);
	}
	if (pr->pr_ip4 == NULL) {
		mtx_unlock(&pr->pr_mtx);
		return (EAFNOSUPPORT);
	}

	ia0.s_addr = ntohl(ia->s_addr);
	if (ia0.s_addr == INADDR_LOOPBACK) {
		ia->s_addr = pr->pr_ip4[0].s_addr;
		mtx_unlock(&pr->pr_mtx);
		return (0);
	}

	if (ia0.s_addr == INADDR_ANY) {
		/*
		 * In case there is only 1 IPv4 address, bind directly.
		 */
		if (pr->pr_ip4s == 1)
			ia->s_addr = pr->pr_ip4[0].s_addr;
		mtx_unlock(&pr->pr_mtx);
		return (0);
	}

	error = _prison_check_ip4(pr, ia);
	mtx_unlock(&pr->pr_mtx);
	return (error);
}

/*
 * Rewrite destination address in case we will connect to loopback address.
 *
 * Returns 0 on success, EAFNOSUPPORT if the jail doesn't allow IPv4.
 * Address passed in in NBO and returned in NBO.
 */
int
prison_remote_ip4(struct ucred *cred, struct in_addr *ia)
{
	struct prison *pr;

	KASSERT(cred != NULL, ("%s: cred is NULL", __func__));
	KASSERT(ia != NULL, ("%s: ia is NULL", __func__));

	pr = cred->cr_prison;
	if (!(pr->pr_flags & PR_IP4))
		return (0);
	mtx_lock(&pr->pr_mtx);
	if (!(pr->pr_flags & PR_IP4)) {
		mtx_unlock(&pr->pr_mtx);
		return (0);
	}
	if (pr->pr_ip4 == NULL) {
		mtx_unlock(&pr->pr_mtx);
		return (EAFNOSUPPORT);
	}

	if (ntohl(ia->s_addr) == INADDR_LOOPBACK) {
		ia->s_addr = pr->pr_ip4[0].s_addr;
		mtx_unlock(&pr->pr_mtx);
		return (0);
	}

	/*
	 * Return success because nothing had to be changed.
	 */
	mtx_unlock(&pr->pr_mtx);
	return (0);
}

/*
 * Check if given address belongs to the jail referenced by cred/prison.
 *
 * Returns 0 if jail doesn't restrict IPv4 or if address belongs to jail,
 * EADDRNOTAVAIL if the address doesn't belong, or EAFNOSUPPORT if the jail
 * doesn't allow IPv4.  Address passed in in NBO.
 */
static int
_prison_check_ip4(struct prison *pr, struct in_addr *ia)
{
	int i, a, z, d;

	/*
	 * Check the primary IP.
	 */
	if (pr->pr_ip4[0].s_addr == ia->s_addr)
		return (0);

	/*
	 * All the other IPs are sorted so we can do a binary search.
	 */
	a = 0;
	z = pr->pr_ip4s - 2;
	while (a <= z) {
		i = (a + z) / 2;
		d = qcmp_v4(&pr->pr_ip4[i+1], ia);
		if (d > 0)
			z = i - 1;
		else if (d < 0)
			a = i + 1;
		else
			return (0);
	}

	return (EADDRNOTAVAIL);
}

int
prison_check_ip4(struct ucred *cred, struct in_addr *ia)
{
	struct prison *pr;
	int error;

	KASSERT(cred != NULL, ("%s: cred is NULL", __func__));
	KASSERT(ia != NULL, ("%s: ia is NULL", __func__));

	pr = cred->cr_prison;
	if (!(pr->pr_flags & PR_IP4))
		return (0);
	mtx_lock(&pr->pr_mtx);
	if (!(pr->pr_flags & PR_IP4)) {
		mtx_unlock(&pr->pr_mtx);
		return (0);
	}
	if (pr->pr_ip4 == NULL) {
		mtx_unlock(&pr->pr_mtx);
		return (EAFNOSUPPORT);
	}

	error = _prison_check_ip4(pr, ia);
	mtx_unlock(&pr->pr_mtx);
	return (error);
}
#endif

#ifdef INET6
static int
prison_restrict_ip6(struct prison *pr, struct in6_addr *newip6)
{
	int ii, ij, used;
	struct prison *ppr;

	ppr = pr->pr_parent;
	if (!(pr->pr_flags & PR_IP6_USER)) {
		/* This has no user settings, so just copy the parent's list. */
		if (pr->pr_ip6s < ppr->pr_ip6s) {
			/*
			 * There's no room for the parent's list.  Use the
			 * new list buffer, which is assumed to be big enough
			 * (if it was passed).  If there's no buffer, try to
			 * allocate one.
			 */
			used = 1;
			if (newip6 == NULL) {
				newip6 = malloc(ppr->pr_ip6s * sizeof(*newip6),
				    M_PRISON, M_NOWAIT);
				if (newip6 != NULL)
					used = 0;
			}
			if (newip6 != NULL) {
				bcopy(ppr->pr_ip6, newip6,
				    ppr->pr_ip6s * sizeof(*newip6));
				free(pr->pr_ip6, M_PRISON);
				pr->pr_ip6 = newip6;
				pr->pr_ip6s = ppr->pr_ip6s;
				pr->pr_flags |= PR_IP6;
			}
			return (used);
		}
		pr->pr_ip6s = ppr->pr_ip6s;
		if (pr->pr_ip6s > 0)
			bcopy(ppr->pr_ip6, pr->pr_ip6,
			    pr->pr_ip6s * sizeof(*newip6));
		else if (pr->pr_ip6 != NULL) {
			free(pr->pr_ip6, M_PRISON);
			pr->pr_ip6 = NULL;
		}
		pr->pr_flags =
			(pr->pr_flags & ~PR_IP6) | (ppr->pr_flags & PR_IP6);
	} else if (pr->pr_ip6s > 0 && (ppr->pr_flags & PR_IP6)) {
		/* Remove addresses that aren't in the parent. */
		for (ij = 0; ij < ppr->pr_ip6s; ij++)
			if (IN6_ARE_ADDR_EQUAL(&pr->pr_ip6[0],
			    &ppr->pr_ip6[ij]))
				break;
		if (ij < ppr->pr_ip6s)
			ii = 1;
		else {
			bcopy(pr->pr_ip6 + 1, pr->pr_ip6,
			    --pr->pr_ip6s * sizeof(*pr->pr_ip6));
			ii = 0;
		}
		for (ij = 1; ii < pr->pr_ip6s; ) {
			if (IN6_ARE_ADDR_EQUAL(&pr->pr_ip6[ii],
			    &ppr->pr_ip6[0])) {
				ii++;
				continue;
			}
			switch (ij >= ppr->pr_ip4s ? -1 :
				qcmp_v6(&pr->pr_ip6[ii], &ppr->pr_ip6[ij])) {
			case -1:
				bcopy(pr->pr_ip6 + ii + 1, pr->pr_ip6 + ii,
				    (--pr->pr_ip6s - ii) * sizeof(*pr->pr_ip6));
				break;
			case 0:
				ii++;
				ij++;
				break;
			case 1:
				ij++;
				break;
			}
		}
		if (pr->pr_ip6s == 0) {
			free(pr->pr_ip6, M_PRISON);
			pr->pr_ip6 = NULL;
		}
	}
	return 0;
}

/*
 * Pass back primary IPv6 address for this jail.
 *
 * If not restricted return success but do not alter the address.  Caller has
 * to make sure to initialize it correctly (e.g. IN6ADDR_ANY_INIT).
 *
 * Returns 0 on success, EAFNOSUPPORT if the jail doesn't allow IPv6.
 */
int
prison_get_ip6(struct ucred *cred, struct in6_addr *ia6)
{
	struct prison *pr;

	KASSERT(cred != NULL, ("%s: cred is NULL", __func__));
	KASSERT(ia6 != NULL, ("%s: ia6 is NULL", __func__));

	pr = cred->cr_prison;
	if (!(pr->pr_flags & PR_IP6))
		return (0);
	mtx_lock(&pr->pr_mtx);
	if (!(pr->pr_flags & PR_IP6)) {
		mtx_unlock(&pr->pr_mtx);
		return (0);
	}
	if (pr->pr_ip6 == NULL) {
		mtx_unlock(&pr->pr_mtx);
		return (EAFNOSUPPORT);
	}

	bcopy(&pr->pr_ip6[0], ia6, sizeof(struct in6_addr));
	mtx_unlock(&pr->pr_mtx);
	return (0);
}

/*
 * Return true if pr1 and pr2 have the same IPv6 address restrictions.
 */
int
prison_equal_ip6(struct prison *pr1, struct prison *pr2)
{

	if (pr1 == pr2)
		return (1);

	sx_slock(&allprison_lock);
	while (pr1 != &prison0 && !(pr1->pr_flags & PR_IP6_USER))
		pr1 = pr1->pr_parent;
	while (pr2 != &prison0 && !(pr2->pr_flags & PR_IP6_USER))
		pr2 = pr2->pr_parent;
	sx_sunlock(&allprison_lock);
	return (pr1 == pr2);
}

/*
 * Make sure our (source) address is set to something meaningful to this jail.
 *
 * v6only should be set based on (inp->inp_flags & IN6P_IPV6_V6ONLY != 0)
 * when needed while binding.
 *
 * Returns 0 if jail doesn't restrict IPv6 or if address belongs to jail,
 * EADDRNOTAVAIL if the address doesn't belong, or EAFNOSUPPORT if the jail
 * doesn't allow IPv6.
 */
int
prison_local_ip6(struct ucred *cred, struct in6_addr *ia6, int v6only)
{
	struct prison *pr;
	int error;

	KASSERT(cred != NULL, ("%s: cred is NULL", __func__));
	KASSERT(ia6 != NULL, ("%s: ia6 is NULL", __func__));

	pr = cred->cr_prison;
	if (!(pr->pr_flags & PR_IP6))
		return (0);
	mtx_lock(&pr->pr_mtx);
	if (!(pr->pr_flags & PR_IP6)) {
		mtx_unlock(&pr->pr_mtx);
		return (0);
	}
	if (pr->pr_ip6 == NULL) {
		mtx_unlock(&pr->pr_mtx);
		return (EAFNOSUPPORT);
	}

	if (IN6_IS_ADDR_LOOPBACK(ia6)) {
		bcopy(&pr->pr_ip6[0], ia6, sizeof(struct in6_addr));
		mtx_unlock(&pr->pr_mtx);
		return (0);
	}

	if (IN6_IS_ADDR_UNSPECIFIED(ia6)) {
		/*
		 * In case there is only 1 IPv6 address, and v6only is true,
		 * then bind directly.
		 */
		if (v6only != 0 && pr->pr_ip6s == 1)
			bcopy(&pr->pr_ip6[0], ia6, sizeof(struct in6_addr));
		mtx_unlock(&pr->pr_mtx);
		return (0);
	}

	error = _prison_check_ip6(pr, ia6);
	mtx_unlock(&pr->pr_mtx);
	return (error);
}

/*
 * Rewrite destination address in case we will connect to loopback address.
 *
 * Returns 0 on success, EAFNOSUPPORT if the jail doesn't allow IPv6.
 */
int
prison_remote_ip6(struct ucred *cred, struct in6_addr *ia6)
{
	struct prison *pr;

	KASSERT(cred != NULL, ("%s: cred is NULL", __func__));
	KASSERT(ia6 != NULL, ("%s: ia6 is NULL", __func__));

	pr = cred->cr_prison;
	if (!(pr->pr_flags & PR_IP6))
		return (0);
	mtx_lock(&pr->pr_mtx);
	if (!(pr->pr_flags & PR_IP6)) {
		mtx_unlock(&pr->pr_mtx);
		return (0);
	}
	if (pr->pr_ip6 == NULL) {
		mtx_unlock(&pr->pr_mtx);
		return (EAFNOSUPPORT);
	}

	if (IN6_IS_ADDR_LOOPBACK(ia6)) {
		bcopy(&pr->pr_ip6[0], ia6, sizeof(struct in6_addr));
		mtx_unlock(&pr->pr_mtx);
		return (0);
	}

	/*
	 * Return success because nothing had to be changed.
	 */
	mtx_unlock(&pr->pr_mtx);
	return (0);
}

/*
 * Check if given address belongs to the jail referenced by cred/prison.
 *
 * Returns 0 if jail doesn't restrict IPv6 or if address belongs to jail,
 * EADDRNOTAVAIL if the address doesn't belong, or EAFNOSUPPORT if the jail
 * doesn't allow IPv6.
 */
static int
_prison_check_ip6(struct prison *pr, struct in6_addr *ia6)
{
	int i, a, z, d;

	/*
	 * Check the primary IP.
	 */
	if (IN6_ARE_ADDR_EQUAL(&pr->pr_ip6[0], ia6))
		return (0);

	/*
	 * All the other IPs are sorted so we can do a binary search.
	 */
	a = 0;
	z = pr->pr_ip6s - 2;
	while (a <= z) {
		i = (a + z) / 2;
		d = qcmp_v6(&pr->pr_ip6[i+1], ia6);
		if (d > 0)
			z = i - 1;
		else if (d < 0)
			a = i + 1;
		else
			return (0);
	}

	return (EADDRNOTAVAIL);
}

int
prison_check_ip6(struct ucred *cred, struct in6_addr *ia6)
{
	struct prison *pr;
	int error;

	KASSERT(cred != NULL, ("%s: cred is NULL", __func__));
	KASSERT(ia6 != NULL, ("%s: ia6 is NULL", __func__));

	pr = cred->cr_prison;
	if (!(pr->pr_flags & PR_IP6))
		return (0);
	mtx_lock(&pr->pr_mtx);
	if (!(pr->pr_flags & PR_IP6)) {
		mtx_unlock(&pr->pr_mtx);
		return (0);
	}
	if (pr->pr_ip6 == NULL) {
		mtx_unlock(&pr->pr_mtx);
		return (EAFNOSUPPORT);
	}

	error = _prison_check_ip6(pr, ia6);
	mtx_unlock(&pr->pr_mtx);
	return (error);
}
#endif

/*
 * Check if a jail supports the given address family.
 *
 * Returns 0 if not jailed or the address family is supported, EAFNOSUPPORT
 * if not.
 */
int
prison_check_af(struct ucred *cred, int af)
{
	struct prison *pr;
	int error;

	KASSERT(cred != NULL, ("%s: cred is NULL", __func__));

	pr = cred->cr_prison;
	error = 0;
	switch (af)
	{
#ifdef INET
	case AF_INET:
		if (pr->pr_flags & PR_IP4)
		{
			mtx_lock(&pr->pr_mtx);
			if ((pr->pr_flags & PR_IP4) && pr->pr_ip4 == NULL)
				error = EAFNOSUPPORT;
			mtx_unlock(&pr->pr_mtx);
		}
		break;
#endif
#ifdef INET6
	case AF_INET6:
		if (pr->pr_flags & PR_IP6)
		{
			mtx_lock(&pr->pr_mtx);
			if ((pr->pr_flags & PR_IP6) && pr->pr_ip6 == NULL)
				error = EAFNOSUPPORT;
			mtx_unlock(&pr->pr_mtx);
		}
		break;
#endif
	case AF_LOCAL:
	case AF_ROUTE:
		break;
	default:
		if (!(pr->pr_allow & PR_ALLOW_SOCKET_AF))
			error = EAFNOSUPPORT;
	}
	return (error);
}

/*
 * Check if given address belongs to the jail referenced by cred (wrapper to
 * prison_check_ip[46]).
 *
 * Returns 0 if jail doesn't restrict the address family or if address belongs
 * to jail, EADDRNOTAVAIL if the address doesn't belong, or EAFNOSUPPORT if
 * the jail doesn't allow the address family.  IPv4 Address passed in in NBO.
 */
int
prison_if(struct ucred *cred, struct sockaddr *sa)
{
#ifdef INET
	struct sockaddr_in *sai;
#endif
#ifdef INET6
	struct sockaddr_in6 *sai6;
#endif
	int error;

	KASSERT(cred != NULL, ("%s: cred is NULL", __func__));
	KASSERT(sa != NULL, ("%s: sa is NULL", __func__));

	error = 0;
	switch (sa->sa_family)
	{
#ifdef INET
	case AF_INET:
		sai = (struct sockaddr_in *)sa;
		error = prison_check_ip4(cred, &sai->sin_addr);
		break;
#endif
#ifdef INET6
	case AF_INET6:
		sai6 = (struct sockaddr_in6 *)sa;
		error = prison_check_ip6(cred, &sai6->sin6_addr);
		break;
#endif
	default:
		if (!(cred->cr_prison->pr_allow & PR_ALLOW_SOCKET_AF))
			error = EAFNOSUPPORT;
	}
	return (error);
}

/*
 * Return 0 if jails permit p1 to frob p2, otherwise ESRCH.
 */
int
prison_check(struct ucred *cred1, struct ucred *cred2)
{

#ifdef VIMAGE
	if (cred2->cr_vimage->v_procg != cred1->cr_vimage->v_procg)
		return (ESRCH);
#endif
	return ((cred1->cr_prison == cred2->cr_prison ||
	    prison_ischild(cred1->cr_prison, cred2->cr_prison)) ? 0 : ESRCH);
}

/*
 * Return 1 if p2 is a child of p1, otherwise 0.
 */
int
prison_ischild(struct prison *pr1, struct prison *pr2)
{

	for (pr2 = pr2->pr_parent; pr2 != NULL; pr2 = pr2->pr_parent)
		if (pr1 == pr2)
			return (1);
	return (0);
}

/*
 * Return 1 if the passed credential is in a jail, otherwise 0.
 */
int
jailed(struct ucred *cred)
{

	return (cred->cr_prison != &prison0);
}

/*
 * Return the correct hostname (domainname, et al) for the passed credential.
 */
void
getcredhostname(struct ucred *cred, char *buf, size_t size)
{
	struct prison *pr;

	/*
	 * A NULL credential can be used to shortcut to the physical
	 * system's hostname.
	 */
	pr = (cred != NULL) ? cred->cr_prison : &prison0;
	mtx_lock(&pr->pr_mtx);
	strlcpy(buf, pr->pr_hostname, size);
	mtx_unlock(&pr->pr_mtx);
}

void
getcreddomainname(struct ucred *cred, char *buf, size_t size)
{

	mtx_lock(&cred->cr_prison->pr_mtx);
	strlcpy(buf, cred->cr_prison->pr_domainname, size);
	mtx_unlock(&cred->cr_prison->pr_mtx);
}

void
getcredhostuuid(struct ucred *cred, char *buf, size_t size)
{

	mtx_lock(&cred->cr_prison->pr_mtx);
	strlcpy(buf, cred->cr_prison->pr_hostuuid, size);
	mtx_unlock(&cred->cr_prison->pr_mtx);
}

void
getcredhostid(struct ucred *cred, unsigned long *hostid)
{

	mtx_lock(&cred->cr_prison->pr_mtx);
	*hostid = cred->cr_prison->pr_hostid;
	mtx_unlock(&cred->cr_prison->pr_mtx);
}

/*
 * Determine whether the subject represented by cred can "see"
 * status of a mount point.
 * Returns: 0 for permitted, ENOENT otherwise.
 * XXX: This function should be called cr_canseemount() and should be
 *      placed in kern_prot.c.
 */
int
prison_canseemount(struct ucred *cred, struct mount *mp)
{
	struct prison *pr;
	struct statfs *sp;
	size_t len;

	pr = cred->cr_prison;
	if (pr->pr_enforce_statfs == 0)
		return (0);
	if (pr->pr_root->v_mount == mp)
		return (0);
	if (pr->pr_enforce_statfs == 2)
		return (ENOENT);
	/*
	 * If jail's chroot directory is set to "/" we should be able to see
	 * all mount-points from inside a jail.
	 * This is ugly check, but this is the only situation when jail's
	 * directory ends with '/'.
	 */
	if (strcmp(pr->pr_path, "/") == 0)
		return (0);
	len = strlen(pr->pr_path);
	sp = &mp->mnt_stat;
	if (strncmp(pr->pr_path, sp->f_mntonname, len) != 0)
		return (ENOENT);
	/*
	 * Be sure that we don't have situation where jail's root directory
	 * is "/some/path" and mount point is "/some/pathpath".
	 */
	if (sp->f_mntonname[len] != '\0' && sp->f_mntonname[len] != '/')
		return (ENOENT);
	return (0);
}

void
prison_enforce_statfs(struct ucred *cred, struct mount *mp, struct statfs *sp)
{
	char jpath[MAXPATHLEN];
	struct prison *pr;
	size_t len;

	pr = cred->cr_prison;
	if (pr->pr_enforce_statfs == 0)
		return;
	if (prison_canseemount(cred, mp) != 0) {
		bzero(sp->f_mntonname, sizeof(sp->f_mntonname));
		strlcpy(sp->f_mntonname, "[restricted]",
		    sizeof(sp->f_mntonname));
		return;
	}
	if (pr->pr_root->v_mount == mp) {
		/*
		 * Clear current buffer data, so we are sure nothing from
		 * the valid path left there.
		 */
		bzero(sp->f_mntonname, sizeof(sp->f_mntonname));
		*sp->f_mntonname = '/';
		return;
	}
	/*
	 * If jail's chroot directory is set to "/" we should be able to see
	 * all mount-points from inside a jail.
	 */
	if (strcmp(pr->pr_path, "/") == 0)
		return;
	len = strlen(pr->pr_path);
	strlcpy(jpath, sp->f_mntonname + len, sizeof(jpath));
	/*
	 * Clear current buffer data, so we are sure nothing from
	 * the valid path left there.
	 */
	bzero(sp->f_mntonname, sizeof(sp->f_mntonname));
	if (*jpath == '\0') {
		/* Should never happen. */
		*sp->f_mntonname = '/';
	} else {
		strlcpy(sp->f_mntonname, jpath, sizeof(sp->f_mntonname));
	}
}

/*
 * Check with permission for a specific privilege is granted within jail.  We
 * have a specific list of accepted privileges; the rest are denied.
 */
int
prison_priv_check(struct ucred *cred, int priv)
{

	if (!jailed(cred))
		return (0);

	switch (priv) {

		/*
		 * Allow ktrace privileges for root in jail.
		 */
	case PRIV_KTRACE:

#if 0
		/*
		 * Allow jailed processes to configure audit identity and
		 * submit audit records (login, etc).  In the future we may
		 * want to further refine the relationship between audit and
		 * jail.
		 */
	case PRIV_AUDIT_GETAUDIT:
	case PRIV_AUDIT_SETAUDIT:
	case PRIV_AUDIT_SUBMIT:
#endif

		/*
		 * Allow jailed processes to manipulate process UNIX
		 * credentials in any way they see fit.
		 */
	case PRIV_CRED_SETUID:
	case PRIV_CRED_SETEUID:
	case PRIV_CRED_SETGID:
	case PRIV_CRED_SETEGID:
	case PRIV_CRED_SETGROUPS:
	case PRIV_CRED_SETREUID:
	case PRIV_CRED_SETREGID:
	case PRIV_CRED_SETRESUID:
	case PRIV_CRED_SETRESGID:

		/*
		 * Jail implements visibility constraints already, so allow
		 * jailed root to override uid/gid-based constraints.
		 */
	case PRIV_SEEOTHERGIDS:
	case PRIV_SEEOTHERUIDS:

		/*
		 * Jail implements inter-process debugging limits already, so
		 * allow jailed root various debugging privileges.
		 */
	case PRIV_DEBUG_DIFFCRED:
	case PRIV_DEBUG_SUGID:
	case PRIV_DEBUG_UNPRIV:

		/*
		 * Allow jail to set various resource limits and login
		 * properties, and for now, exceed process resource limits.
		 */
	case PRIV_PROC_LIMIT:
	case PRIV_PROC_SETLOGIN:
	case PRIV_PROC_SETRLIMIT:

		/*
		 * System V and POSIX IPC privileges are granted in jail.
		 */
	case PRIV_IPC_READ:
	case PRIV_IPC_WRITE:
	case PRIV_IPC_ADMIN:
	case PRIV_IPC_MSGSIZE:
	case PRIV_MQ_ADMIN:

		/*
		 * Jail operations within a jail work on child jails.
		 */
	case PRIV_JAIL_ATTACH:
	case PRIV_JAIL_SET:
	case PRIV_JAIL_REMOVE:

		/*
		 * Jail implements its own inter-process limits, so allow
		 * root processes in jail to change scheduling on other
		 * processes in the same jail.  Likewise for signalling.
		 */
	case PRIV_SCHED_DIFFCRED:
	case PRIV_SCHED_CPUSET:
	case PRIV_SIGNAL_DIFFCRED:
	case PRIV_SIGNAL_SUGID:

		/*
		 * Allow jailed processes to write to sysctls marked as jail
		 * writable.
		 */
	case PRIV_SYSCTL_WRITEJAIL:

		/*
		 * Allow root in jail to manage a variety of quota
		 * properties.  These should likely be conditional on a
		 * configuration option.
		 */
	case PRIV_VFS_GETQUOTA:
	case PRIV_VFS_SETQUOTA:

		/*
		 * Since Jail relies on chroot() to implement file system
		 * protections, grant many VFS privileges to root in jail.
		 * Be careful to exclude mount-related and NFS-related
		 * privileges.
		 */
	case PRIV_VFS_READ:
	case PRIV_VFS_WRITE:
	case PRIV_VFS_ADMIN:
	case PRIV_VFS_EXEC:
	case PRIV_VFS_LOOKUP:
	case PRIV_VFS_BLOCKRESERVE:	/* XXXRW: Slightly surprising. */
	case PRIV_VFS_CHFLAGS_DEV:
	case PRIV_VFS_CHOWN:
	case PRIV_VFS_CHROOT:
	case PRIV_VFS_RETAINSUGID:
	case PRIV_VFS_FCHROOT:
	case PRIV_VFS_LINK:
	case PRIV_VFS_SETGID:
	case PRIV_VFS_STAT:
	case PRIV_VFS_STICKYFILE:
		return (0);

		/*
		 * Depending on the global setting, allow privilege of
		 * setting system flags.
		 */
	case PRIV_VFS_SYSFLAGS:
		if (cred->cr_prison->pr_allow & PR_ALLOW_CHFLAGS)
			return (0);
		else
			return (EPERM);

		/*
		 * Depending on the global setting, allow privilege of
		 * mounting/unmounting file systems.
		 */
	case PRIV_VFS_MOUNT:
	case PRIV_VFS_UNMOUNT:
	case PRIV_VFS_MOUNT_NONUSER:
	case PRIV_VFS_MOUNT_OWNER:
		if (cred->cr_prison->pr_allow & PR_ALLOW_MOUNT)
			return (0);
		else
			return (EPERM);

		/*
		 * Allow jailed root to bind reserved ports and reuse in-use
		 * ports.
		 */
	case PRIV_NETINET_RESERVEDPORT:
	case PRIV_NETINET_REUSEPORT:
		return (0);

		/*
		 * Allow jailed root to set certian IPv4/6 (option) headers.
		 */
	case PRIV_NETINET_SETHDROPTS:
		return (0);

		/*
		 * Conditionally allow creating raw sockets in jail.
		 */
	case PRIV_NETINET_RAW:
		if (cred->cr_prison->pr_allow & PR_ALLOW_RAW_SOCKETS)
			return (0);
		else
			return (EPERM);

		/*
		 * Since jail implements its own visibility limits on netstat
		 * sysctls, allow getcred.  This allows identd to work in
		 * jail.
		 */
	case PRIV_NETINET_GETCRED:
		return (0);

	default:
		/*
		 * In all remaining cases, deny the privilege request.  This
		 * includes almost all network privileges, many system
		 * configuration privileges.
		 */
		return (EPERM);
	}
}

/*
 * Return the part of pr2's name that is relative to pr1, or the whole name
 * if it does not directly follow.
 */

char *
prison_name(struct prison *pr1, struct prison *pr2)
{
	char *name;

	/* Jails see themselves as "0" (if they see themselves at all). */
	if (pr1 == pr2)
		return "0";
	name = pr2->pr_name;
	if (prison_ischild(pr1, pr2)) {
		/*
		 * pr1 isn't locked (and allprison_lock may not be either)
		 * so its length can't be counted on.  But the number of dots
		 * can be counted on - and counted.
		 */
		for (; pr1 != &prison0; pr1 = pr1->pr_parent)
			name = strchr(name, '.') + 1;
	}
	return (name);
}

/*
 * Return the part of pr2's path that is relative to pr1, or the whole path
 * if it does not directly follow.
 */
static char *
prison_path(struct prison *pr1, struct prison *pr2)
{
	char *path1, *path2;
	int len1;

	path1 = pr1->pr_path;
	path2 = pr2->pr_path;
	if (!strcmp(path1, "/"))
		return (path2);
	len1 = strlen(path1);
	if (strncmp(path1, path2, len1))
		return (path2);
	if (path2[len1] == '\0')
		return "/";
	if (path2[len1] == '/')
		return (path2 + len1);
	return (path2);
}


/*
 * Jail-related sysctls.
 */
SYSCTL_NODE(_security, OID_AUTO, jail, CTLFLAG_RW, 0,
    "Jails");

static int
sysctl_jail_list(SYSCTL_HANDLER_ARGS)
{
	struct xprison *xp;
	struct prison *pr, *cpr;
#ifdef INET
	struct in_addr *ip4 = NULL;
	int ip4s = 0;
#endif
#ifdef INET6
	struct in_addr *ip6 = NULL;
	int ip6s = 0;
#endif
	int descend, error;

	xp = malloc(sizeof(*xp), M_TEMP, M_WAITOK);
	pr = req->td->td_ucred->cr_prison;
	error = 0;
	sx_slock(&allprison_lock);
	FOREACH_PRISON_DESCENDANT(pr, cpr, descend) {
#if defined(INET) || defined(INET6)
 again:
#endif
		mtx_lock(&cpr->pr_mtx);
#ifdef INET
		if (cpr->pr_ip4s > 0) {
			if (ip4s < cpr->pr_ip4s) {
				ip4s = cpr->pr_ip4s;
				mtx_unlock(&cpr->pr_mtx);
				ip4 = realloc(ip4, ip4s *
				    sizeof(struct in_addr), M_TEMP, M_WAITOK);
				goto again;
			}
			bcopy(cpr->pr_ip4, ip4,
			    cpr->pr_ip4s * sizeof(struct in_addr));
		}
#endif
#ifdef INET6
		if (cpr->pr_ip6s > 0) {
			if (ip6s < cpr->pr_ip6s) {
				ip6s = cpr->pr_ip6s;
				mtx_unlock(&cpr->pr_mtx);
				ip6 = realloc(ip6, ip6s *
				    sizeof(struct in6_addr), M_TEMP, M_WAITOK);
				goto again;
			}
			bcopy(cpr->pr_ip6, ip6,
			    cpr->pr_ip6s * sizeof(struct in6_addr));
		}
#endif
		if (cpr->pr_ref == 0) {
			mtx_unlock(&cpr->pr_mtx);
			continue;
		}
		bzero(xp, sizeof(*xp));
		xp->pr_version = XPRISON_VERSION;
		xp->pr_id = cpr->pr_id;
		xp->pr_state = cpr->pr_uref > 0
		    ? PRISON_STATE_ALIVE : PRISON_STATE_DYING;
		strlcpy(xp->pr_path, prison_path(pr, cpr), sizeof(xp->pr_path));
		strlcpy(xp->pr_host, cpr->pr_hostname, sizeof(xp->pr_host));
		strlcpy(xp->pr_name, prison_name(pr, cpr), sizeof(xp->pr_name));
#ifdef INET
		xp->pr_ip4s = cpr->pr_ip4s;
#endif
#ifdef INET6
		xp->pr_ip6s = cpr->pr_ip6s;
#endif
		mtx_unlock(&cpr->pr_mtx);
		error = SYSCTL_OUT(req, xp, sizeof(*xp));
		if (error)
			break;
#ifdef INET
		if (xp->pr_ip4s > 0) {
			error = SYSCTL_OUT(req, ip4,
			    xp->pr_ip4s * sizeof(struct in_addr));
			if (error)
				break;
		}
#endif
#ifdef INET6
		if (xp->pr_ip6s > 0) {
			error = SYSCTL_OUT(req, ip6,
			    xp->pr_ip6s * sizeof(struct in6_addr));
			if (error)
				break;
		}
#endif
	}
	sx_sunlock(&allprison_lock);
	free(xp, M_TEMP);
#ifdef INET
	free(ip4, M_TEMP);
#endif
#ifdef INET6
	free(ip6, M_TEMP);
#endif
	return (error);
}

SYSCTL_OID(_security_jail, OID_AUTO, list,
    CTLTYPE_STRUCT | CTLFLAG_RD | CTLFLAG_MPSAFE, NULL, 0,
    sysctl_jail_list, "S", "List of active jails");

static int
sysctl_jail_jailed(SYSCTL_HANDLER_ARGS)
{
	int error, injail;

	injail = jailed(req->td->td_ucred);
	error = SYSCTL_OUT(req, &injail, sizeof(injail));

	return (error);
}

SYSCTL_PROC(_security_jail, OID_AUTO, jailed,
    CTLTYPE_INT | CTLFLAG_RD | CTLFLAG_MPSAFE, NULL, 0,
    sysctl_jail_jailed, "I", "Process in jail?");

#if defined(INET) || defined(INET6)
SYSCTL_UINT(_security_jail, OID_AUTO, jail_max_af_ips, CTLFLAG_RW,
    &jail_max_af_ips, 0,
    "Number of IP addresses a jail may have at most per address family");
#endif

/*
 * Default parameters for jail(2) compatability.  For historical reasons,
 * the sysctl names have varying similarity to the parameter names.  Prisons
 * just see their own parameters, and can't change them.
 */
static int
sysctl_jail_default_allow(SYSCTL_HANDLER_ARGS)
{
	struct prison *pr;
	int allow, error, i;

	pr = req->td->td_ucred->cr_prison;
	allow = (pr == &prison0) ? jail_default_allow : pr->pr_allow;

	/* Get the current flag value, and convert it to a boolean. */
	i = (allow & arg2) ? 1 : 0;
	if (arg1 != NULL)
		i = !i;
	error = sysctl_handle_int(oidp, &i, 0, req);
	if (error || !req->newptr)
		return (error);
	i = i ? arg2 : 0;
	if (arg1 != NULL)
		i ^= arg2;
	/*
	 * The sysctls don't have CTLFLAGS_PRISON, so assume prison0
	 * for writing.
	 */
	mtx_lock(&prison0.pr_mtx);
	jail_default_allow = (jail_default_allow & ~arg2) | i;
	mtx_unlock(&prison0.pr_mtx);
	return (0);
}

SYSCTL_PROC(_security_jail, OID_AUTO, set_hostname_allowed,
    CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_MPSAFE,
    NULL, PR_ALLOW_SET_HOSTNAME, sysctl_jail_default_allow, "I",
    "Processes in jail can set their hostnames");
SYSCTL_PROC(_security_jail, OID_AUTO, socket_unixiproute_only,
    CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_MPSAFE,
    (void *)1, PR_ALLOW_SOCKET_AF, sysctl_jail_default_allow, "I",
    "Processes in jail are limited to creating UNIX/IP/route sockets only");
SYSCTL_PROC(_security_jail, OID_AUTO, sysvipc_allowed,
    CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_MPSAFE,
    NULL, PR_ALLOW_SYSVIPC, sysctl_jail_default_allow, "I",
    "Processes in jail can use System V IPC primitives");
SYSCTL_PROC(_security_jail, OID_AUTO, allow_raw_sockets,
    CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_MPSAFE,
    NULL, PR_ALLOW_RAW_SOCKETS, sysctl_jail_default_allow, "I",
    "Prison root can create raw sockets");
SYSCTL_PROC(_security_jail, OID_AUTO, chflags_allowed,
    CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_MPSAFE,
    NULL, PR_ALLOW_CHFLAGS, sysctl_jail_default_allow, "I",
    "Processes in jail can alter system file flags");
SYSCTL_PROC(_security_jail, OID_AUTO, mount_allowed,
    CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_MPSAFE,
    NULL, PR_ALLOW_MOUNT, sysctl_jail_default_allow, "I",
    "Processes in jail can mount/unmount jail-friendly file systems");

static int
sysctl_jail_default_level(SYSCTL_HANDLER_ARGS)
{
	struct prison *pr;
	int level, error;

	pr = req->td->td_ucred->cr_prison;
	level = (pr == &prison0) ? *(int *)arg1 : *(int *)((char *)pr + arg2);
	error = sysctl_handle_int(oidp, &level, 0, req);
	if (error || !req->newptr)
		return (error);
	*(int *)arg1 = level;
	return (0);
}

SYSCTL_PROC(_security_jail, OID_AUTO, enforce_statfs,
    CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_MPSAFE,
    &jail_default_enforce_statfs, offsetof(struct prison, pr_enforce_statfs),
    sysctl_jail_default_level, "I",
    "Processes in jail cannot see all mounted file systems");

/*
 * Nodes to describe jail parameters.  Maximum length of string parameters
 * is returned in the string itself, and the other parameters exist merely
 * to make themselves and their types known.
 */
SYSCTL_NODE(_security_jail, OID_AUTO, param, CTLFLAG_RW, 0,
    "Jail parameters");

int
sysctl_jail_param(SYSCTL_HANDLER_ARGS)
{
	int i;
	long l;
	size_t s;
	char numbuf[12];

	switch (oidp->oid_kind & CTLTYPE)
	{
	case CTLTYPE_LONG:
	case CTLTYPE_ULONG:
		l = 0;
#ifdef SCTL_MASK32
		if (!(req->flags & SCTL_MASK32))
#endif
			return (SYSCTL_OUT(req, &l, sizeof(l)));
	case CTLTYPE_INT:
	case CTLTYPE_UINT:
		i = 0;
		return (SYSCTL_OUT(req, &i, sizeof(i)));
	case CTLTYPE_STRING:
		snprintf(numbuf, sizeof(numbuf), "%d", arg2);
		return
		    (sysctl_handle_string(oidp, numbuf, sizeof(numbuf), req));
	case CTLTYPE_STRUCT:
		s = (size_t)arg2;
		return (SYSCTL_OUT(req, &s, sizeof(s)));
	}
	return (0);
}

SYSCTL_JAIL_PARAM(, jid, CTLTYPE_INT | CTLFLAG_RDTUN, "I", "Jail ID");
SYSCTL_JAIL_PARAM(, parent, CTLTYPE_INT | CTLFLAG_RD, "I", "Jail parent ID");
SYSCTL_JAIL_PARAM_STRING(, name, CTLFLAG_RW, MAXHOSTNAMELEN, "Jail name");
SYSCTL_JAIL_PARAM_STRING(, path, CTLFLAG_RDTUN, MAXPATHLEN, "Jail root path");
SYSCTL_JAIL_PARAM(, securelevel, CTLTYPE_INT | CTLFLAG_RW,
    "I", "Jail secure level");
SYSCTL_JAIL_PARAM(, enforce_statfs, CTLTYPE_INT | CTLFLAG_RW,
    "I", "Jail cannot see all mounted file systems");
SYSCTL_JAIL_PARAM(, persist, CTLTYPE_INT | CTLFLAG_RW,
    "B", "Jail persistence");
#ifdef VIMAGE
SYSCTL_JAIL_PARAM(, vnet, CTLTYPE_INT | CTLFLAG_RDTUN,
    "B", "Virtual network stack");
#endif
SYSCTL_JAIL_PARAM(, dying, CTLTYPE_INT | CTLFLAG_RD,
    "B", "Jail is in the process of shutting down");

SYSCTL_JAIL_PARAM_NODE(host, "Jail host info");
SYSCTL_JAIL_PARAM(, nohost, CTLTYPE_INT | CTLFLAG_RW,
    "BN", "Jail w/ no host info");
SYSCTL_JAIL_PARAM_STRING(_host, hostname, CTLFLAG_RW, MAXHOSTNAMELEN,
    "Jail hostname");
SYSCTL_JAIL_PARAM_STRING(_host, domainname, CTLFLAG_RW, MAXHOSTNAMELEN,
    "Jail NIS domainname");
SYSCTL_JAIL_PARAM_STRING(_host, hostuuid, CTLFLAG_RW, HOSTUUIDLEN,
    "Jail host UUID");
SYSCTL_JAIL_PARAM(_host, hostid, CTLTYPE_ULONG | CTLFLAG_RW,
    "LU", "Jail host ID");

SYSCTL_JAIL_PARAM_NODE(cpuset, "Jail cpuset");
SYSCTL_JAIL_PARAM(_cpuset, id, CTLTYPE_INT | CTLFLAG_RD, "I", "Jail cpuset ID");

#ifdef INET
SYSCTL_JAIL_PARAM_NODE(ip4, "Jail IPv4 address virtualization");
SYSCTL_JAIL_PARAM(, noip4, CTLTYPE_INT | CTLFLAG_RW,
    "BN", "Jail w/ no IP address virtualization");
SYSCTL_JAIL_PARAM_STRUCT(_ip4, addr, CTLFLAG_RW, sizeof(struct in_addr),
    "S,in_addr,a", "Jail IPv4 addresses");
#endif
#ifdef INET6
SYSCTL_JAIL_PARAM_NODE(ip6, "Jail IPv6 address virtualization");
SYSCTL_JAIL_PARAM(, noip6, CTLTYPE_INT | CTLFLAG_RW,
    "BN", "Jail w/ no IP address virtualization");
SYSCTL_JAIL_PARAM_STRUCT(_ip6, addr, CTLFLAG_RW, sizeof(struct in6_addr),
    "S,in6_addr,a", "Jail IPv6 addresses");
#endif

SYSCTL_JAIL_PARAM_NODE(allow, "Jail permission flags");
SYSCTL_JAIL_PARAM(_allow, set_hostname, CTLTYPE_INT | CTLFLAG_RW,
    "B", "Jail may set hostname");
SYSCTL_JAIL_PARAM(_allow, sysvipc, CTLTYPE_INT | CTLFLAG_RW,
    "B", "Jail may use SYSV IPC");
SYSCTL_JAIL_PARAM(_allow, raw_sockets, CTLTYPE_INT | CTLFLAG_RW,
    "B", "Jail may create raw sockets");
SYSCTL_JAIL_PARAM(_allow, chflags, CTLTYPE_INT | CTLFLAG_RW,
    "B", "Jail may alter system file flags");
SYSCTL_JAIL_PARAM(_allow, mount, CTLTYPE_INT | CTLFLAG_RW,
    "B", "Jail may mount/unmount jail-friendly file systems");
SYSCTL_JAIL_PARAM(_allow, quotas, CTLTYPE_INT | CTLFLAG_RW,
    "B", "Jail may set file quotas");
SYSCTL_JAIL_PARAM(_allow, jails, CTLTYPE_INT | CTLFLAG_RW,
    "B", "Jail may create child jails");
SYSCTL_JAIL_PARAM(_allow, socket_af, CTLTYPE_INT | CTLFLAG_RW,
    "B", "Jail may create sockets other than just UNIX/IPv4/IPv6/route");


#ifdef DDB

static void
db_show_prison(struct prison *pr)
{
	int fi;
#if defined(INET) || defined(INET6)
	int ii;
#endif
#ifdef INET6
	char ip6buf[INET6_ADDRSTRLEN];
#endif

	db_printf("prison %p:\n", pr);
	db_printf(" jid             = %d\n", pr->pr_id);
	db_printf(" name            = %s\n", pr->pr_name);
	db_printf(" parent          = %p\n", pr->pr_parent);
	db_printf(" ref             = %d\n", pr->pr_ref);
	db_printf(" uref            = %d\n", pr->pr_uref);
	db_printf(" path            = %s\n", pr->pr_path);
	db_printf(" cpuset          = %d\n", pr->pr_cpuset
	    ? pr->pr_cpuset->cs_id : -1);
#ifdef VIMAGE
	db_printf(" vnet            = %p\n", pr->pr_vnet);
#endif
	db_printf(" root            = %p\n", pr->pr_root);
	db_printf(" securelevel     = %d\n", pr->pr_securelevel);
	db_printf(" child           = %p\n", LIST_FIRST(&pr->pr_children));
	db_printf(" sibling         = %p\n", LIST_NEXT(pr, pr_sibling));
	db_printf(" flags           = %x", pr->pr_flags);
	for (fi = 0; fi < sizeof(pr_flag_names) / sizeof(pr_flag_names[0]);
	    fi++)
		if (pr_flag_names[fi] != NULL && (pr->pr_flags & (1 << fi)))
			db_printf(" %s", pr_flag_names[fi]);
	db_printf(" allow           = %x", pr->pr_allow);
	for (fi = 0; fi < sizeof(pr_allow_names) / sizeof(pr_allow_names[0]);
	    fi++)
		if (pr_allow_names[fi] != NULL && (pr->pr_allow & (1 << fi)))
			db_printf(" %s", pr_allow_names[fi]);
	db_printf("\n");
	db_printf(" enforce_statfs  = %d\n", pr->pr_enforce_statfs);
	db_printf(" host.hostname   = %s\n", pr->pr_hostname);
	db_printf(" host.domainname = %s\n", pr->pr_domainname);
	db_printf(" host.hostuuid   = %s\n", pr->pr_hostuuid);
	db_printf(" host.hostid     = %lu\n", pr->pr_hostid);
#ifdef INET
	db_printf(" ip4s            = %d\n", pr->pr_ip4s);
	for (ii = 0; ii < pr->pr_ip4s; ii++)
		db_printf(" %s %s\n",
		    ii == 0 ? "ip4             =" : "                 ",
		    inet_ntoa(pr->pr_ip4[ii]));
#endif
#ifdef INET6
	db_printf(" ip6s            = %d\n", pr->pr_ip6s);
	for (ii = 0; ii < pr->pr_ip6s; ii++)
		db_printf(" %s %s\n",
		    ii == 0 ? "ip6             =" : "                 ",
		    ip6_sprintf(ip6buf, &pr->pr_ip6[ii]));
#endif
}

DB_SHOW_COMMAND(prison, db_show_prison_command)
{
	struct prison *pr;

	if (!have_addr) {
		/*
		 * Show all prisons in the list, and prison0 which is not
		 * listed.
		 */
		db_show_prison(&prison0);
		if (!db_pager_quit) {
			TAILQ_FOREACH(pr, &allprison, pr_list) {
				db_show_prison(pr);
				if (db_pager_quit)
					break;
			}
		}
		return;
	}

	if (addr == 0)
		pr = &prison0;
	else {
		/* Look for a prison with the ID and with references. */
		TAILQ_FOREACH(pr, &allprison, pr_list)
			if (pr->pr_id == addr && pr->pr_ref > 0)
				break;
		if (pr == NULL)
			/* Look again, without requiring a reference. */
			TAILQ_FOREACH(pr, &allprison, pr_list)
				if (pr->pr_id == addr)
					break;
		if (pr == NULL)
			/* Assume address points to a valid prison. */
			pr = (struct prison *)addr;
	}
	db_show_prison(pr);
}

#endif /* DDB */