1999-05-04 18:20:53 +00:00
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|
|
.\"
|
2003-11-20 02:46:44 +00:00
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|
|
.\" Copyright (c) 2000, 2003 Robert N. M. Watson
|
2001-12-14 10:18:15 +00:00
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|
.\" All rights reserved.
|
2000-02-20 02:51:11 +00:00
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.\"
|
2001-12-14 10:18:15 +00:00
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.\" Redistribution and use in source and binary forms, with or without
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.\" modification, are permitted provided that the following conditions
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.\" are met:
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.\" 1. Redistributions of source code must retain the above copyright
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.\" notice, this list of conditions and the following disclaimer.
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.\" 2. Redistributions in binary form must reproduce the above copyright
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.\" notice, this list of conditions and the following disclaimer in the
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.\" documentation and/or other materials provided with the distribution.
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2000-02-20 02:51:11 +00:00
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.\"
|
2001-12-14 10:18:15 +00:00
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.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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.\" SUCH DAMAGE.
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2000-02-20 02:51:11 +00:00
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.\"
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.\"
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2001-12-14 10:18:15 +00:00
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.\" ----------------------------------------------------------------------------
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.\" "THE BEER-WARE LICENSE" (Revision 42):
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.\" <phk@FreeBSD.ORG> wrote this file. As long as you retain this notice you
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|
.\" can do whatever you want with this stuff. If we meet some day, and you think
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|
.\" this stuff is worth it, you can buy me a beer in return. Poul-Henning Kamp
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.\" ----------------------------------------------------------------------------
|
1999-05-04 18:20:53 +00:00
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|
.\"
|
2001-12-14 10:18:15 +00:00
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.\" $FreeBSD$
|
1999-05-04 18:20:53 +00:00
|
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|
.\"
|
2003-04-09 03:04:12 +00:00
|
|
|
.Dd April 8, 2003
|
This Implements the mumbled about "Jail" feature.
This is a seriously beefed up chroot kind of thing. The process
is jailed along the same lines as a chroot does it, but with
additional tough restrictions imposed on what the superuser can do.
For all I know, it is safe to hand over the root bit inside a
prison to the customer living in that prison, this is what
it was developed for in fact: "real virtual servers".
Each prison has an ip number associated with it, which all IP
communications will be coerced to use and each prison has its own
hostname.
Needless to say, you need more RAM this way, but the advantage is
that each customer can run their own particular version of apache
and not stomp on the toes of their neighbors.
It generally does what one would expect, but setting up a jail
still takes a little knowledge.
A few notes:
I have no scripts for setting up a jail, don't ask me for them.
The IP number should be an alias on one of the interfaces.
mount a /proc in each jail, it will make ps more useable.
/proc/<pid>/status tells the hostname of the prison for
jailed processes.
Quotas are only sensible if you have a mountpoint per prison.
There are no privisions for stopping resource-hogging.
Some "#ifdef INET" and similar may be missing (send patches!)
If somebody wants to take it from here and develop it into
more of a "virtual machine" they should be most welcome!
Tools, comments, patches & documentation most welcome.
Have fun...
Sponsored by: http://www.rndassociates.com/
Run for almost a year by: http://www.servetheweb.com/
1999-04-28 11:38:52 +00:00
|
|
|
.Dt JAIL 8
|
2001-07-10 15:12:08 +00:00
|
|
|
.Os
|
This Implements the mumbled about "Jail" feature.
This is a seriously beefed up chroot kind of thing. The process
is jailed along the same lines as a chroot does it, but with
additional tough restrictions imposed on what the superuser can do.
For all I know, it is safe to hand over the root bit inside a
prison to the customer living in that prison, this is what
it was developed for in fact: "real virtual servers".
Each prison has an ip number associated with it, which all IP
communications will be coerced to use and each prison has its own
hostname.
Needless to say, you need more RAM this way, but the advantage is
that each customer can run their own particular version of apache
and not stomp on the toes of their neighbors.
It generally does what one would expect, but setting up a jail
still takes a little knowledge.
A few notes:
I have no scripts for setting up a jail, don't ask me for them.
The IP number should be an alias on one of the interfaces.
mount a /proc in each jail, it will make ps more useable.
/proc/<pid>/status tells the hostname of the prison for
jailed processes.
Quotas are only sensible if you have a mountpoint per prison.
There are no privisions for stopping resource-hogging.
Some "#ifdef INET" and similar may be missing (send patches!)
If somebody wants to take it from here and develop it into
more of a "virtual machine" they should be most welcome!
Tools, comments, patches & documentation most welcome.
Have fun...
Sponsored by: http://www.rndassociates.com/
Run for almost a year by: http://www.servetheweb.com/
1999-04-28 11:38:52 +00:00
|
|
|
.Sh NAME
|
|
|
|
|
.Nm jail
|
2001-12-14 10:18:15 +00:00
|
|
|
.Nd "imprison process and its descendants"
|
This Implements the mumbled about "Jail" feature.
This is a seriously beefed up chroot kind of thing. The process
is jailed along the same lines as a chroot does it, but with
additional tough restrictions imposed on what the superuser can do.
For all I know, it is safe to hand over the root bit inside a
prison to the customer living in that prison, this is what
it was developed for in fact: "real virtual servers".
Each prison has an ip number associated with it, which all IP
communications will be coerced to use and each prison has its own
hostname.
Needless to say, you need more RAM this way, but the advantage is
that each customer can run their own particular version of apache
and not stomp on the toes of their neighbors.
It generally does what one would expect, but setting up a jail
still takes a little knowledge.
A few notes:
I have no scripts for setting up a jail, don't ask me for them.
The IP number should be an alias on one of the interfaces.
mount a /proc in each jail, it will make ps more useable.
/proc/<pid>/status tells the hostname of the prison for
jailed processes.
Quotas are only sensible if you have a mountpoint per prison.
There are no privisions for stopping resource-hogging.
Some "#ifdef INET" and similar may be missing (send patches!)
If somebody wants to take it from here and develop it into
more of a "virtual machine" they should be most welcome!
Tools, comments, patches & documentation most welcome.
Have fun...
Sponsored by: http://www.rndassociates.com/
Run for almost a year by: http://www.servetheweb.com/
1999-04-28 11:38:52 +00:00
|
|
|
.Sh SYNOPSIS
|
2000-11-20 20:10:44 +00:00
|
|
|
.Nm
|
2003-04-09 03:04:12 +00:00
|
|
|
.Op Fl i
|
2003-03-27 12:16:58 +00:00
|
|
|
.Op Fl u Ar username
|
2001-12-14 10:18:15 +00:00
|
|
|
.Ar path hostname ip-number command ...
|
This Implements the mumbled about "Jail" feature.
This is a seriously beefed up chroot kind of thing. The process
is jailed along the same lines as a chroot does it, but with
additional tough restrictions imposed on what the superuser can do.
For all I know, it is safe to hand over the root bit inside a
prison to the customer living in that prison, this is what
it was developed for in fact: "real virtual servers".
Each prison has an ip number associated with it, which all IP
communications will be coerced to use and each prison has its own
hostname.
Needless to say, you need more RAM this way, but the advantage is
that each customer can run their own particular version of apache
and not stomp on the toes of their neighbors.
It generally does what one would expect, but setting up a jail
still takes a little knowledge.
A few notes:
I have no scripts for setting up a jail, don't ask me for them.
The IP number should be an alias on one of the interfaces.
mount a /proc in each jail, it will make ps more useable.
/proc/<pid>/status tells the hostname of the prison for
jailed processes.
Quotas are only sensible if you have a mountpoint per prison.
There are no privisions for stopping resource-hogging.
Some "#ifdef INET" and similar may be missing (send patches!)
If somebody wants to take it from here and develop it into
more of a "virtual machine" they should be most welcome!
Tools, comments, patches & documentation most welcome.
Have fun...
Sponsored by: http://www.rndassociates.com/
Run for almost a year by: http://www.servetheweb.com/
1999-04-28 11:38:52 +00:00
|
|
|
.Sh DESCRIPTION
|
|
|
|
|
The
|
|
|
|
|
.Nm
|
2002-07-14 14:47:15 +00:00
|
|
|
utility imprisons a process and all future descendants.
|
This Implements the mumbled about "Jail" feature.
This is a seriously beefed up chroot kind of thing. The process
is jailed along the same lines as a chroot does it, but with
additional tough restrictions imposed on what the superuser can do.
For all I know, it is safe to hand over the root bit inside a
prison to the customer living in that prison, this is what
it was developed for in fact: "real virtual servers".
Each prison has an ip number associated with it, which all IP
communications will be coerced to use and each prison has its own
hostname.
Needless to say, you need more RAM this way, but the advantage is
that each customer can run their own particular version of apache
and not stomp on the toes of their neighbors.
It generally does what one would expect, but setting up a jail
still takes a little knowledge.
A few notes:
I have no scripts for setting up a jail, don't ask me for them.
The IP number should be an alias on one of the interfaces.
mount a /proc in each jail, it will make ps more useable.
/proc/<pid>/status tells the hostname of the prison for
jailed processes.
Quotas are only sensible if you have a mountpoint per prison.
There are no privisions for stopping resource-hogging.
Some "#ifdef INET" and similar may be missing (send patches!)
If somebody wants to take it from here and develop it into
more of a "virtual machine" they should be most welcome!
Tools, comments, patches & documentation most welcome.
Have fun...
Sponsored by: http://www.rndassociates.com/
Run for almost a year by: http://www.servetheweb.com/
1999-04-28 11:38:52 +00:00
|
|
|
.Pp
|
2003-03-27 12:16:58 +00:00
|
|
|
The options are as follows:
|
|
|
|
|
.Bl -tag -width ".Fl u Ar username"
|
2003-04-09 03:04:12 +00:00
|
|
|
.It Fl i
|
|
|
|
|
Output the jail identifier of the newly created jail.
|
2003-03-27 12:16:58 +00:00
|
|
|
.It Fl u Ar username
|
|
|
|
|
The user name as whom the
|
|
|
|
|
.Ar command
|
|
|
|
|
should run.
|
|
|
|
|
.It Ar path
|
|
|
|
|
Directory which is to be the root of the prison.
|
|
|
|
|
.It Ar hostname
|
|
|
|
|
Hostname of the prison.
|
|
|
|
|
.It Ar ip-number
|
|
|
|
|
IP number assigned to the prison.
|
|
|
|
|
.It Ar command
|
|
|
|
|
Pathname of the program which is to be executed.
|
|
|
|
|
.El
|
|
|
|
|
.Pp
|
2003-11-20 03:47:50 +00:00
|
|
|
Jails are typically set up using one of two philosophies: either to
|
|
|
|
|
constrain a specific application (possibly running with privilege), or
|
|
|
|
|
to create a "virtual system image" running a variety of daemons and
|
|
|
|
|
services.
|
|
|
|
|
In both cases, a fairly complete file system install of FreeBSD is
|
|
|
|
|
required, so as to provide the necessary command line tools, daemons,
|
|
|
|
|
libraries, application configuration files, etc are available.
|
|
|
|
|
However, for a virtual server configuration, a fair amount of
|
|
|
|
|
additional work is required so as to configure the "boot" process.
|
|
|
|
|
This man page documents the configuration steps necessary to support
|
|
|
|
|
either of these steps, althoguh the configuration steps may be
|
|
|
|
|
refined based on local requirements.
|
|
|
|
|
.Pp
|
This Implements the mumbled about "Jail" feature.
This is a seriously beefed up chroot kind of thing. The process
is jailed along the same lines as a chroot does it, but with
additional tough restrictions imposed on what the superuser can do.
For all I know, it is safe to hand over the root bit inside a
prison to the customer living in that prison, this is what
it was developed for in fact: "real virtual servers".
Each prison has an ip number associated with it, which all IP
communications will be coerced to use and each prison has its own
hostname.
Needless to say, you need more RAM this way, but the advantage is
that each customer can run their own particular version of apache
and not stomp on the toes of their neighbors.
It generally does what one would expect, but setting up a jail
still takes a little knowledge.
A few notes:
I have no scripts for setting up a jail, don't ask me for them.
The IP number should be an alias on one of the interfaces.
mount a /proc in each jail, it will make ps more useable.
/proc/<pid>/status tells the hostname of the prison for
jailed processes.
Quotas are only sensible if you have a mountpoint per prison.
There are no privisions for stopping resource-hogging.
Some "#ifdef INET" and similar may be missing (send patches!)
If somebody wants to take it from here and develop it into
more of a "virtual machine" they should be most welcome!
Tools, comments, patches & documentation most welcome.
Have fun...
Sponsored by: http://www.rndassociates.com/
Run for almost a year by: http://www.servetheweb.com/
1999-04-28 11:38:52 +00:00
|
|
|
Please see the
|
|
|
|
|
.Xr jail 2
|
1999-05-05 19:23:45 +00:00
|
|
|
man page for further details.
|
1999-07-09 21:35:50 +00:00
|
|
|
.Sh EXAMPLES
|
2001-12-14 10:18:15 +00:00
|
|
|
.Ss "Setting up a Jail Directory Tree"
|
2001-12-14 20:20:50 +00:00
|
|
|
This example shows how to setup a jail directory tree
|
2002-01-10 15:14:22 +00:00
|
|
|
containing an entire
|
|
|
|
|
.Fx
|
|
|
|
|
distribution:
|
2001-07-15 08:06:20 +00:00
|
|
|
.Bd -literal
|
1999-07-09 21:35:50 +00:00
|
|
|
D=/here/is/the/jail
|
|
|
|
|
cd /usr/src
|
2001-12-14 20:20:50 +00:00
|
|
|
mkdir -p $D
|
2001-03-11 20:37:11 +00:00
|
|
|
make world DESTDIR=$D
|
1999-07-09 21:35:50 +00:00
|
|
|
cd etc
|
2002-10-22 15:03:51 +00:00
|
|
|
make distribution DESTDIR=$D
|
2003-02-28 22:47:18 +00:00
|
|
|
mount_devfs devfs $D/dev
|
1999-07-09 21:35:50 +00:00
|
|
|
cd $D
|
|
|
|
|
ln -sf dev/null kernel
|
|
|
|
|
.Ed
|
2001-12-14 20:20:50 +00:00
|
|
|
.Pp
|
2003-06-26 19:04:15 +00:00
|
|
|
NOTE: It is important that only appropriate device nodes in devfs be
|
|
|
|
|
exposed to a jail; access to disk devices in the jail may permit processes
|
|
|
|
|
in the jail to bypass the jail sandboxing by modifying files outside of
|
|
|
|
|
the jail.
|
|
|
|
|
See
|
|
|
|
|
.Xr devfs 8
|
|
|
|
|
for information on how to use devfs rules to limit access to entries
|
|
|
|
|
in the per-jail devfs.
|
|
|
|
|
.Pp
|
2001-12-14 20:20:50 +00:00
|
|
|
In many cases this example would put far more stuff in the jail than is needed.
|
2002-01-10 15:15:44 +00:00
|
|
|
In the other extreme case a jail might contain only one single file:
|
2001-12-14 20:20:50 +00:00
|
|
|
the executable to be run in the jail.
|
|
|
|
|
.Pp
|
|
|
|
|
We recommend experimentation and caution that it is a lot easier to
|
2002-01-10 15:14:22 +00:00
|
|
|
start with a
|
|
|
|
|
.Dq fat
|
|
|
|
|
jail and remove things until it stops working,
|
|
|
|
|
than it is to start with a
|
|
|
|
|
.Dq thin
|
|
|
|
|
jail and add things until it works.
|
2001-12-14 10:18:15 +00:00
|
|
|
.Ss "Setting Up a Jail"
|
2000-02-13 05:15:29 +00:00
|
|
|
Do what was described in
|
2001-12-14 10:18:15 +00:00
|
|
|
.Sx "Setting Up a Jail Directory Tree"
|
|
|
|
|
to build the jail directory tree.
|
|
|
|
|
For the sake of this example, we will
|
2000-02-13 05:15:29 +00:00
|
|
|
assume you built it in
|
|
|
|
|
.Pa /data/jail/192.168.11.100 ,
|
2001-12-14 10:18:15 +00:00
|
|
|
named for the jailed IP address.
|
|
|
|
|
Substitute below as needed with your
|
2000-02-13 05:15:29 +00:00
|
|
|
own directory, IP address, and hostname.
|
2003-11-20 03:47:50 +00:00
|
|
|
.Ss "Setting up the Host Environment"
|
2000-02-13 05:15:29 +00:00
|
|
|
First, you will want to set up your real system's environment to be
|
2001-02-01 16:44:04 +00:00
|
|
|
.Dq jail-friendly .
|
2000-02-13 05:15:29 +00:00
|
|
|
For consistency, we will refer to the parent box as the
|
2001-12-14 10:18:15 +00:00
|
|
|
.Dq "host environment" ,
|
2000-02-13 05:15:29 +00:00
|
|
|
and to the jailed virtual machine as the
|
2001-12-14 10:18:15 +00:00
|
|
|
.Dq "jail environment" .
|
2000-02-13 05:15:29 +00:00
|
|
|
Because jail is implemented using IP aliases, one of the first things to do
|
|
|
|
|
is to disable IP services on the host system that listen on all local
|
2001-12-14 10:18:15 +00:00
|
|
|
IP addresses for a service.
|
2003-11-20 03:47:50 +00:00
|
|
|
If a network service is present in the host environment that binds all
|
|
|
|
|
available IP addresses rather than specific IP addresses, it may service
|
|
|
|
|
requests sent to jail IP addresses.
|
2001-12-14 10:18:15 +00:00
|
|
|
This means changing
|
2000-03-24 02:05:54 +00:00
|
|
|
.Xr inetd 8
|
|
|
|
|
to only listen on the
|
2001-12-14 10:18:15 +00:00
|
|
|
appropriate IP address, and so forth.
|
|
|
|
|
Add the following to
|
2000-02-13 05:15:29 +00:00
|
|
|
.Pa /etc/rc.conf
|
|
|
|
|
in the host environment:
|
|
|
|
|
.Bd -literal -offset indent
|
|
|
|
|
sendmail_enable="NO"
|
2000-02-16 23:50:43 +00:00
|
|
|
inetd_flags="-wW -a 192.168.11.23"
|
2003-03-18 14:01:02 +00:00
|
|
|
rpcbind_enable="NO"
|
2000-02-13 05:15:29 +00:00
|
|
|
.Ed
|
|
|
|
|
.Pp
|
2002-05-20 07:29:25 +00:00
|
|
|
.Li 192.168.11.23
|
2001-12-14 10:18:15 +00:00
|
|
|
is the native IP address for the host system, in this example.
|
|
|
|
|
Daemons that run out of
|
2000-02-18 19:02:22 +00:00
|
|
|
.Xr inetd 8
|
2001-12-14 10:18:15 +00:00
|
|
|
can be easily set to use only the specified host IP address.
|
|
|
|
|
Other daemons
|
|
|
|
|
will need to be manually configured\(emfor some this is possible through
|
2000-02-18 19:02:22 +00:00
|
|
|
the
|
|
|
|
|
.Xr rc.conf 5
|
2003-11-20 03:47:50 +00:00
|
|
|
flags entries, for others it is necessary to modify per-application
|
|
|
|
|
configuration files, or to recompile the application.
|
|
|
|
|
The following frequently deployed services must have their individual
|
|
|
|
|
configuration files modified to limit the application to listening
|
|
|
|
|
to a specific IP address:
|
|
|
|
|
.Pp
|
|
|
|
|
To configure
|
|
|
|
|
.Xr sshd 8 ,
|
|
|
|
|
it is necessary to modify
|
|
|
|
|
.Pa /etc/ssh/sshd_config .
|
2000-02-18 19:02:22 +00:00
|
|
|
.Pp
|
2003-11-20 03:47:50 +00:00
|
|
|
To configure
|
2000-02-18 19:02:22 +00:00
|
|
|
.Xr sendmail 8 ,
|
2003-11-20 03:47:50 +00:00
|
|
|
it is necessary to modify
|
|
|
|
|
.Pa /etc/mail/sendmail.cf .
|
|
|
|
|
.Pp
|
|
|
|
|
For
|
2000-02-18 19:02:22 +00:00
|
|
|
.Xr named 8 ,
|
2003-11-20 03:47:50 +00:00
|
|
|
it is necessary to modify
|
|
|
|
|
.Pa /etc/namedb/named.conf .
|
|
|
|
|
.Pp
|
|
|
|
|
In addition, a number of services must be recompiled in order to run
|
|
|
|
|
them in the host environment.
|
|
|
|
|
This includes most applications providing services using
|
|
|
|
|
.Xr rpc 3 ,
|
|
|
|
|
such as
|
|
|
|
|
.Xr rpcbind 8,
|
|
|
|
|
.Xr nfsd 8 ,
|
2000-02-18 19:02:22 +00:00
|
|
|
and
|
2003-11-20 03:47:50 +00:00
|
|
|
.Xr mountd 8 .
|
|
|
|
|
In general, applications for which it is not possible to specify which
|
|
|
|
|
IP address to bind should not be run in the host environment unless they
|
|
|
|
|
should also service requests sent to jail IP addresses.
|
2001-09-03 15:42:10 +00:00
|
|
|
Attempting to serve
|
2000-02-18 19:02:22 +00:00
|
|
|
NFS from the host environment may also cause confusion, and cannot be
|
|
|
|
|
easily reconfigured to use only specific IPs, as some NFS services are
|
2001-12-14 10:18:15 +00:00
|
|
|
hosted directly from the kernel.
|
|
|
|
|
Any third party network software running
|
2000-02-18 19:02:22 +00:00
|
|
|
in the host environment should also be checked and configured so that it
|
|
|
|
|
does not bind all IP addresses, which would result in those services also
|
|
|
|
|
appearing to be offered by the jail environments.
|
|
|
|
|
.Pp
|
|
|
|
|
Once
|
|
|
|
|
these daemons have been disabled or fixed in the host environment, it is
|
|
|
|
|
best to reboot so that all daemons are in a known state, to reduce the
|
|
|
|
|
potential for confusion later (such as finding that when you send mail
|
|
|
|
|
to a jail, and its sendmail is down, the mail is delivered to the host,
|
|
|
|
|
etc.)
|
2003-11-20 03:47:50 +00:00
|
|
|
.Ss Configuring the Jail
|
2000-02-18 19:02:22 +00:00
|
|
|
.Pp
|
|
|
|
|
Start any jails for the first time without configuring the network
|
2001-12-14 10:18:15 +00:00
|
|
|
interface so that you can clean it up a little and set up accounts.
|
|
|
|
|
As
|
2000-02-13 05:15:29 +00:00
|
|
|
with any machine (virtual or not) you will need to set a root password, time
|
2001-12-14 10:18:15 +00:00
|
|
|
zone, etc.
|
2003-11-20 03:47:50 +00:00
|
|
|
Some of these steps apply only if you intend to run a full virtual server
|
|
|
|
|
inside the jail; others apply for both constraining a particular application
|
|
|
|
|
or for a virtual server.
|
2000-02-13 05:15:29 +00:00
|
|
|
.Pp
|
2003-11-20 02:46:44 +00:00
|
|
|
Start a shell in the jail:
|
2000-02-13 05:15:29 +00:00
|
|
|
.Pp
|
2001-12-14 10:18:15 +00:00
|
|
|
.Dl "jail /data/jail/192.168.11.100 testhostname 192.168.11.100 /bin/sh"
|
|
|
|
|
.Pp
|
|
|
|
|
You will end up with a shell prompt, assuming no errors, within the jail.
|
|
|
|
|
You can now run
|
2003-11-20 03:47:50 +00:00
|
|
|
.Pa /usr/sbin/sysinstall
|
2000-02-13 05:15:29 +00:00
|
|
|
and do the post-install configuration to set various configuration options,
|
2001-12-14 10:18:15 +00:00
|
|
|
or perform these actions manually by editing
|
|
|
|
|
.Pa /etc/rc.conf ,
|
|
|
|
|
etc.
|
2000-02-13 05:15:29 +00:00
|
|
|
.Pp
|
|
|
|
|
.Bl -bullet -offset indent -compact
|
|
|
|
|
.It
|
2001-12-14 10:18:15 +00:00
|
|
|
Create an empty
|
|
|
|
|
.Pa /etc/fstab
|
2003-11-20 03:47:50 +00:00
|
|
|
to quell startup warnings about missing fstab (virtual server only)
|
2000-02-18 19:02:22 +00:00
|
|
|
.It
|
2001-12-14 10:18:15 +00:00
|
|
|
Disable the port mapper
|
|
|
|
|
.Pa ( /etc/rc.conf :
|
2003-03-18 14:01:02 +00:00
|
|
|
.Li rpcbind_enable="NO" )
|
2003-11-20 03:47:50 +00:00
|
|
|
(virtual server only)
|
2000-02-18 19:02:22 +00:00
|
|
|
.It
|
2000-02-20 02:51:11 +00:00
|
|
|
Run
|
|
|
|
|
.Xr newaliases 1
|
2001-12-14 10:18:15 +00:00
|
|
|
to quell
|
|
|
|
|
.Xr sendmail 8
|
|
|
|
|
warnings.
|
2000-02-20 02:51:11 +00:00
|
|
|
.It
|
2001-12-14 10:18:15 +00:00
|
|
|
Disable interface configuration to quell startup warnings about
|
|
|
|
|
.Xr ifconfig 8
|
|
|
|
|
.Pq Li network_interfaces=""
|
2003-11-20 03:47:50 +00:00
|
|
|
(virtual server only)
|
2000-02-18 19:02:22 +00:00
|
|
|
.It
|
2001-12-14 10:18:15 +00:00
|
|
|
Configure
|
|
|
|
|
.Pa /etc/resolv.conf
|
2000-02-18 19:02:22 +00:00
|
|
|
so that name resolution within the jail will work correctly
|
2000-02-13 05:15:29 +00:00
|
|
|
.It
|
|
|
|
|
Set a root password, probably different from the real host system
|
|
|
|
|
.It
|
|
|
|
|
Set the timezone
|
|
|
|
|
.It
|
|
|
|
|
Add accounts for users in the jail environment
|
|
|
|
|
.It
|
2003-11-20 03:47:50 +00:00
|
|
|
Install any packages the environment requires
|
2000-02-13 05:15:29 +00:00
|
|
|
.El
|
|
|
|
|
.Pp
|
2000-02-18 19:02:22 +00:00
|
|
|
You may also want to perform any package-specific configuration (web servers,
|
2001-12-14 10:18:15 +00:00
|
|
|
SSH servers, etc), patch up
|
|
|
|
|
.Pa /etc/syslog.conf
|
|
|
|
|
so it logs as you would like, etc.
|
2003-11-20 03:47:50 +00:00
|
|
|
If you are not using a virtual server, you may wish to modify
|
|
|
|
|
.Xr syslogd 8
|
|
|
|
|
in the host environment to listen on the syslog socket in the jail
|
|
|
|
|
environment; in this example, the syslog socket would be stored in
|
|
|
|
|
.Pa /data/jail/192.168.11.100/var/run/log .
|
2000-02-13 05:15:29 +00:00
|
|
|
.Pp
|
|
|
|
|
Exit from the shell, and the jail will be shut down.
|
2001-12-14 10:18:15 +00:00
|
|
|
.Ss "Starting the Jail"
|
2000-02-13 05:15:29 +00:00
|
|
|
You are now ready to restart the jail and bring up the environment with
|
2001-12-14 10:18:15 +00:00
|
|
|
all of its daemons and other programs.
|
2003-11-20 03:47:50 +00:00
|
|
|
If you are running a single application in the jail, substitute the
|
|
|
|
|
command used to start the application for
|
|
|
|
|
.Pa /etc/rc
|
|
|
|
|
in the examples below.
|
|
|
|
|
To start a virtual server environment,
|
|
|
|
|
.Pa /etc/rc
|
|
|
|
|
is run to launch various daemons and services.
|
2001-12-14 10:18:15 +00:00
|
|
|
To do this, first bring up the
|
2000-02-13 05:15:29 +00:00
|
|
|
virtual host interface, and then start the jail's
|
|
|
|
|
.Pa /etc/rc
|
|
|
|
|
script from within the jail.
|
2000-02-18 19:02:22 +00:00
|
|
|
.Pp
|
|
|
|
|
NOTE: If you plan to allow untrusted users to have root access inside the
|
2001-12-14 10:18:15 +00:00
|
|
|
jail, you may wish to consider setting the
|
2002-01-16 06:55:30 +00:00
|
|
|
.Va security.jail.set_hostname_allowed
|
2003-11-20 03:47:50 +00:00
|
|
|
sysctl variable to 0.
|
|
|
|
|
Please see the management discussion later in this document as to why this
|
|
|
|
|
is a good idea.
|
2001-12-14 10:18:15 +00:00
|
|
|
If you do decide to set this variable,
|
2001-12-12 05:24:50 +00:00
|
|
|
it must be set before starting any jails, and once each boot.
|
2000-02-13 05:15:29 +00:00
|
|
|
.Bd -literal -offset indent
|
2001-12-14 10:18:15 +00:00
|
|
|
ifconfig ed0 inet alias 192.168.11.100/32
|
|
|
|
|
mount -t procfs proc /data/jail/192.168.11.100/proc
|
|
|
|
|
jail /data/jail/192.168.11.100 testhostname 192.168.11.100 \\
|
2000-02-13 05:15:29 +00:00
|
|
|
/bin/sh /etc/rc
|
|
|
|
|
.Ed
|
|
|
|
|
.Pp
|
|
|
|
|
A few warnings will be produced, because most
|
|
|
|
|
.Xr sysctl 8
|
|
|
|
|
configuration variables cannot be set from within the jail, as they are
|
2000-03-01 14:09:25 +00:00
|
|
|
global across all jails and the host environment.
|
|
|
|
|
However, it should all
|
|
|
|
|
work properly.
|
|
|
|
|
You should be able to see
|
2000-02-13 05:15:29 +00:00
|
|
|
.Xr inetd 8 ,
|
|
|
|
|
.Xr syslogd 8 ,
|
|
|
|
|
and other processes running within the jail using
|
|
|
|
|
.Xr ps 1 ,
|
|
|
|
|
with the
|
2001-12-14 10:18:15 +00:00
|
|
|
.Ql J
|
|
|
|
|
flag appearing beside jailed processes.
|
2003-04-09 03:04:12 +00:00
|
|
|
To see an active list of jails, use the
|
|
|
|
|
.Xr jls 8
|
|
|
|
|
utility.
|
2001-12-14 10:18:15 +00:00
|
|
|
You should also be able to
|
|
|
|
|
.Xr telnet 1
|
|
|
|
|
to the hostname or IP address of the jailed environment, and log
|
2000-03-24 02:05:54 +00:00
|
|
|
in using the accounts you created previously.
|
2001-12-14 10:18:15 +00:00
|
|
|
.Ss "Managing the Jail"
|
2000-02-13 05:15:29 +00:00
|
|
|
Normal machine shutdown commands, such as
|
|
|
|
|
.Xr halt 8 ,
|
|
|
|
|
.Xr reboot 8 ,
|
|
|
|
|
and
|
|
|
|
|
.Xr shutdown 8 ,
|
2001-12-14 10:18:15 +00:00
|
|
|
cannot be used successfully within the jail.
|
|
|
|
|
To kill all processes in a
|
2000-02-13 05:15:29 +00:00
|
|
|
jail, you may log into the jail and, as root, use one of the following
|
|
|
|
|
commands, depending on what you want to accomplish:
|
|
|
|
|
.Pp
|
2001-12-14 10:18:15 +00:00
|
|
|
.Bd -literal -offset indent
|
|
|
|
|
kill -TERM -1
|
|
|
|
|
kill -KILL -1
|
|
|
|
|
.Ed
|
2000-02-13 05:15:29 +00:00
|
|
|
.Pp
|
|
|
|
|
This will send the
|
2001-12-14 10:18:15 +00:00
|
|
|
.Dv SIGTERM
|
2000-02-13 05:15:29 +00:00
|
|
|
or
|
2001-12-14 10:18:15 +00:00
|
|
|
.Dv SIGKILL
|
|
|
|
|
signals to all processes in the jail from within the jail.
|
|
|
|
|
Depending on
|
2000-02-13 05:15:29 +00:00
|
|
|
the intended use of the jail, you may also want to run
|
|
|
|
|
.Pa /etc/rc.shutdown
|
2001-12-14 10:18:15 +00:00
|
|
|
from within the jail.
|
2003-04-09 03:04:12 +00:00
|
|
|
To kill processes from outside the jail, use the
|
|
|
|
|
.Xr jexec 8
|
|
|
|
|
utility in conjuction with the one of the
|
|
|
|
|
.Xr kill 1
|
|
|
|
|
commands above, or use the
|
|
|
|
|
.Xr killall 1
|
|
|
|
|
utility with the
|
|
|
|
|
.Fl j
|
|
|
|
|
option.
|
2000-02-13 05:15:29 +00:00
|
|
|
.Pp
|
2001-12-14 10:18:15 +00:00
|
|
|
The
|
|
|
|
|
.Pa /proc/ Ns Ar pid Ns Pa /status
|
2000-02-13 05:15:29 +00:00
|
|
|
file contains, as its last field, the hostname of the jail in which the
|
|
|
|
|
process runs, or
|
2001-12-14 10:18:15 +00:00
|
|
|
.Dq Li -
|
|
|
|
|
to indicate that the process is not running within a jail.
|
|
|
|
|
The
|
2000-02-13 05:15:29 +00:00
|
|
|
.Xr ps 1
|
|
|
|
|
command also shows a
|
2001-12-14 10:18:15 +00:00
|
|
|
.Ql J
|
|
|
|
|
flag for processes in a jail.
|
|
|
|
|
However, the hostname for a jail may be, by
|
2000-02-13 05:15:29 +00:00
|
|
|
default, modified from within the jail, so the
|
|
|
|
|
.Pa /proc
|
2001-12-14 10:18:15 +00:00
|
|
|
status entry is unreliable by default.
|
|
|
|
|
To disable the setting of the hostname
|
2000-02-13 05:15:29 +00:00
|
|
|
from within a jail, set the
|
2002-01-16 06:55:30 +00:00
|
|
|
.Va security.jail.set_hostname_allowed
|
2000-02-20 02:51:11 +00:00
|
|
|
sysctl variable in the host environment to 0, which will affect all jails.
|
2001-12-14 10:18:15 +00:00
|
|
|
You can have this sysctl set on each boot using
|
2000-02-20 02:51:11 +00:00
|
|
|
.Xr sysctl.conf 5 .
|
2001-12-14 10:18:15 +00:00
|
|
|
Just add the following line to
|
|
|
|
|
.Pa /etc/sysctl.conf :
|
|
|
|
|
.Pp
|
2002-01-16 06:55:30 +00:00
|
|
|
.Dl security.jail.set_hostname_allowed=0
|
2001-12-14 10:18:15 +00:00
|
|
|
.Ss "Sysctl MIB Entries"
|
2000-10-31 01:47:59 +00:00
|
|
|
Certain aspects of the jail containments environment may be modified from
|
|
|
|
|
the host environment using
|
|
|
|
|
.Xr sysctl 8
|
|
|
|
|
MIB variables.
|
|
|
|
|
Currently, these variables affect all jails on the system, although in
|
|
|
|
|
the future this functionality may be finer grained.
|
2000-11-01 07:49:29 +00:00
|
|
|
.Bl -tag -width XXX
|
2002-01-16 06:55:30 +00:00
|
|
|
.It Va security.jail.set_hostname_allowed
|
2000-10-31 01:47:59 +00:00
|
|
|
This MIB entry determines whether or not processes within a jail are
|
|
|
|
|
allowed to change their hostname via
|
|
|
|
|
.Xr hostname 1
|
|
|
|
|
or
|
|
|
|
|
.Xr sethostname 3 .
|
|
|
|
|
In the current jail implementation, the ability to set the hostname from
|
|
|
|
|
within the jail can impact management tools relying on the accuracy of jail
|
2000-11-01 07:49:29 +00:00
|
|
|
information in
|
|
|
|
|
.Pa /proc .
|
2000-10-31 01:47:59 +00:00
|
|
|
As such, this should be disabled in environments where privileged access to
|
|
|
|
|
jails is given out to untrusted parties.
|
2002-01-16 06:55:30 +00:00
|
|
|
.It Va security.jail.socket_unixiproute_only
|
2000-10-31 01:47:59 +00:00
|
|
|
The jail functionality binds an IPv4 address to each jail, and limits
|
|
|
|
|
access to other network addresses in the IPv4 space that may be available
|
|
|
|
|
in the host environment.
|
|
|
|
|
However, jail is not currently able to limit access to other network
|
|
|
|
|
protocol stacks that have not had jail functionality added to them.
|
|
|
|
|
As such, by default, processes within jails may only access protocols
|
2000-11-01 07:49:29 +00:00
|
|
|
in the following domains:
|
2001-12-14 10:18:15 +00:00
|
|
|
.Dv PF_LOCAL , PF_INET ,
|
2000-11-01 07:49:29 +00:00
|
|
|
and
|
|
|
|
|
.Dv PF_ROUTE ,
|
2001-12-14 10:18:15 +00:00
|
|
|
permitting them access to
|
|
|
|
|
.Ux
|
|
|
|
|
domain sockets,
|
2000-11-01 07:51:14 +00:00
|
|
|
IPv4 addresses, and routing sockets.
|
2000-10-31 01:47:59 +00:00
|
|
|
To enable access to other domains, this MIB variable may be set to
|
|
|
|
|
0.
|
2002-01-16 06:55:30 +00:00
|
|
|
.It Va security.jail.sysvipc_allowed
|
2000-10-31 01:47:59 +00:00
|
|
|
This MIB entry determines whether or not processes within a jail have access
|
|
|
|
|
to System V IPC primitives.
|
|
|
|
|
In the current jail implementation, System V primitives share a single
|
|
|
|
|
namespace across the host and jail environments, meaning that processes
|
|
|
|
|
within a jail would be able to communicate with (and potentially interfere
|
|
|
|
|
with) processes outside of the jail, and in other jails.
|
|
|
|
|
As such, this functionality is disabled by default, but can be enabled
|
|
|
|
|
by setting this MIB entry to 1.
|
2000-11-01 07:49:29 +00:00
|
|
|
.El
|
2003-11-11 18:34:29 +00:00
|
|
|
.Pp
|
|
|
|
|
There are currently two MIB related variables that have per-jail settings.
|
|
|
|
|
Changes to these variables by a jailed process do not effect the host
|
|
|
|
|
environment, only the jail environment.
|
|
|
|
|
The variables are
|
|
|
|
|
.Va kern.securelevel
|
|
|
|
|
and
|
|
|
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.Va kern.hostname .
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This Implements the mumbled about "Jail" feature.
This is a seriously beefed up chroot kind of thing. The process
is jailed along the same lines as a chroot does it, but with
additional tough restrictions imposed on what the superuser can do.
For all I know, it is safe to hand over the root bit inside a
prison to the customer living in that prison, this is what
it was developed for in fact: "real virtual servers".
Each prison has an ip number associated with it, which all IP
communications will be coerced to use and each prison has its own
hostname.
Needless to say, you need more RAM this way, but the advantage is
that each customer can run their own particular version of apache
and not stomp on the toes of their neighbors.
It generally does what one would expect, but setting up a jail
still takes a little knowledge.
A few notes:
I have no scripts for setting up a jail, don't ask me for them.
The IP number should be an alias on one of the interfaces.
mount a /proc in each jail, it will make ps more useable.
/proc/<pid>/status tells the hostname of the prison for
jailed processes.
Quotas are only sensible if you have a mountpoint per prison.
There are no privisions for stopping resource-hogging.
Some "#ifdef INET" and similar may be missing (send patches!)
If somebody wants to take it from here and develop it into
more of a "virtual machine" they should be most welcome!
Tools, comments, patches & documentation most welcome.
Have fun...
Sponsored by: http://www.rndassociates.com/
Run for almost a year by: http://www.servetheweb.com/
1999-04-28 11:38:52 +00:00
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.Sh SEE ALSO
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2003-04-09 03:04:12 +00:00
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.Xr killall 1 ,
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2000-02-20 02:51:11 +00:00
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.Xr newaliases 1 ,
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.Xr ps 1 ,
|
This Implements the mumbled about "Jail" feature.
This is a seriously beefed up chroot kind of thing. The process
is jailed along the same lines as a chroot does it, but with
additional tough restrictions imposed on what the superuser can do.
For all I know, it is safe to hand over the root bit inside a
prison to the customer living in that prison, this is what
it was developed for in fact: "real virtual servers".
Each prison has an ip number associated with it, which all IP
communications will be coerced to use and each prison has its own
hostname.
Needless to say, you need more RAM this way, but the advantage is
that each customer can run their own particular version of apache
and not stomp on the toes of their neighbors.
It generally does what one would expect, but setting up a jail
still takes a little knowledge.
A few notes:
I have no scripts for setting up a jail, don't ask me for them.
The IP number should be an alias on one of the interfaces.
mount a /proc in each jail, it will make ps more useable.
/proc/<pid>/status tells the hostname of the prison for
jailed processes.
Quotas are only sensible if you have a mountpoint per prison.
There are no privisions for stopping resource-hogging.
Some "#ifdef INET" and similar may be missing (send patches!)
If somebody wants to take it from here and develop it into
more of a "virtual machine" they should be most welcome!
Tools, comments, patches & documentation most welcome.
Have fun...
Sponsored by: http://www.rndassociates.com/
Run for almost a year by: http://www.servetheweb.com/
1999-04-28 11:38:52 +00:00
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.Xr chroot 2 ,
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2000-02-20 02:51:11 +00:00
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.Xr jail 2 ,
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2003-04-09 03:04:12 +00:00
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.Xr jail_attach 2 ,
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2000-02-20 02:51:11 +00:00
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.Xr procfs 5 ,
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.Xr rc.conf 5 ,
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.Xr sysctl.conf 5 ,
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2003-06-26 19:04:15 +00:00
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.Xr devfs 8 ,
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2000-02-20 02:51:11 +00:00
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.Xr halt 8 ,
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.Xr inetd 8 ,
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2003-04-09 03:04:12 +00:00
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.Xr jexec 8 ,
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.Xr jls 8 ,
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2003-02-28 22:47:18 +00:00
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.Xr mount_devfs 8 ,
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2000-02-20 02:51:11 +00:00
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.Xr named 8 ,
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.Xr reboot 8 ,
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2001-07-05 08:13:03 +00:00
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.Xr rpcbind 8 ,
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2000-02-20 02:51:11 +00:00
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.Xr sendmail 8 ,
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.Xr shutdown 8 ,
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.Xr sysctl 8 ,
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.Xr syslogd 8
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This Implements the mumbled about "Jail" feature.
This is a seriously beefed up chroot kind of thing. The process
is jailed along the same lines as a chroot does it, but with
additional tough restrictions imposed on what the superuser can do.
For all I know, it is safe to hand over the root bit inside a
prison to the customer living in that prison, this is what
it was developed for in fact: "real virtual servers".
Each prison has an ip number associated with it, which all IP
communications will be coerced to use and each prison has its own
hostname.
Needless to say, you need more RAM this way, but the advantage is
that each customer can run their own particular version of apache
and not stomp on the toes of their neighbors.
It generally does what one would expect, but setting up a jail
still takes a little knowledge.
A few notes:
I have no scripts for setting up a jail, don't ask me for them.
The IP number should be an alias on one of the interfaces.
mount a /proc in each jail, it will make ps more useable.
/proc/<pid>/status tells the hostname of the prison for
jailed processes.
Quotas are only sensible if you have a mountpoint per prison.
There are no privisions for stopping resource-hogging.
Some "#ifdef INET" and similar may be missing (send patches!)
If somebody wants to take it from here and develop it into
more of a "virtual machine" they should be most welcome!
Tools, comments, patches & documentation most welcome.
Have fun...
Sponsored by: http://www.rndassociates.com/
Run for almost a year by: http://www.servetheweb.com/
1999-04-28 11:38:52 +00:00
|
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.Sh HISTORY
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The
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2001-08-27 12:15:44 +00:00
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.Nm
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2002-07-14 14:47:15 +00:00
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utility appeared in
|
This Implements the mumbled about "Jail" feature.
This is a seriously beefed up chroot kind of thing. The process
is jailed along the same lines as a chroot does it, but with
additional tough restrictions imposed on what the superuser can do.
For all I know, it is safe to hand over the root bit inside a
prison to the customer living in that prison, this is what
it was developed for in fact: "real virtual servers".
Each prison has an ip number associated with it, which all IP
communications will be coerced to use and each prison has its own
hostname.
Needless to say, you need more RAM this way, but the advantage is
that each customer can run their own particular version of apache
and not stomp on the toes of their neighbors.
It generally does what one would expect, but setting up a jail
still takes a little knowledge.
A few notes:
I have no scripts for setting up a jail, don't ask me for them.
The IP number should be an alias on one of the interfaces.
mount a /proc in each jail, it will make ps more useable.
/proc/<pid>/status tells the hostname of the prison for
jailed processes.
Quotas are only sensible if you have a mountpoint per prison.
There are no privisions for stopping resource-hogging.
Some "#ifdef INET" and similar may be missing (send patches!)
If somebody wants to take it from here and develop it into
more of a "virtual machine" they should be most welcome!
Tools, comments, patches & documentation most welcome.
Have fun...
Sponsored by: http://www.rndassociates.com/
Run for almost a year by: http://www.servetheweb.com/
1999-04-28 11:38:52 +00:00
|
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|
.Fx 4.0 .
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1999-12-21 11:25:10 +00:00
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.Sh AUTHORS
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2001-12-14 10:18:15 +00:00
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.An -nosplit
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2000-03-24 02:05:54 +00:00
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The jail feature was written by
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.An Poul-Henning Kamp
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for R&D Associates
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2001-12-14 10:18:15 +00:00
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.Pa http://www.rndassociates.com/
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2000-11-14 11:20:58 +00:00
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who contributed it to
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.Fx .
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2000-02-20 02:51:11 +00:00
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.Pp
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2001-12-14 10:18:15 +00:00
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.An Robert Watson
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wrote the extended documentation, found a few bugs, added
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2000-02-16 23:50:43 +00:00
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a few new features, and cleaned up the userland jail environment.
|
2000-02-18 19:02:22 +00:00
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.Sh BUGS
|
2003-04-09 03:04:12 +00:00
|
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Jail currently lacks the ability to allow access to
|
2000-02-18 19:02:22 +00:00
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specific jail information via
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.Xr ps 1
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as opposed to
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.Xr procfs 5 .
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Similarly, it might be a good idea to add an
|
2001-12-14 10:18:15 +00:00
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address alias flag such that daemons listening on all IPs
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.Pq Dv INADDR_ANY
|
2000-02-18 19:02:22 +00:00
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will not bind on that address, which would facilitate building a safe
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host environment such that host daemons do not impose on services offered
|
2001-12-14 10:18:15 +00:00
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from within jails.
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Currently, the simplist answer is to minimize services
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2000-03-24 02:05:54 +00:00
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offered on the host, possibly limiting it to services offered from
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.Xr inetd 8
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2000-02-18 19:02:22 +00:00
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which is easily configurable.
|
