mdoc(7) police overhaul.
This commit is contained in:
parent
9a665c3136
commit
1a6ec3e8a3
Notes:
svn2git
2020-12-20 02:59:44 +00:00
svn path=/head/; revision=87863
@ -1,51 +1,47 @@
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.\"
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.\"Copyright (c) 2000 Robert N. M. Watson
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.\"All rights reserved.
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.\" Copyright (c) 2000 Robert N. M. Watson
|
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.\" 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.
|
||||
.\" 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.
|
||||
.\" 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.
|
||||
.\"
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||||
.\"
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.\"----------------------------------------------------------------------------
|
||||
.\""THE BEER-WARE LICENSE" (Revision 42):
|
||||
.\"<phk@FreeBSD.ORG> wrote this file. As long as you retain this notice you
|
||||
.\"can do whatever you want with this stuff. If we meet some day, and you think
|
||||
.\"this stuff is worth it, you can buy me a beer in return. Poul-Henning Kamp
|
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.\"----------------------------------------------------------------------------
|
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.\" ----------------------------------------------------------------------------
|
||||
.\" "THE BEER-WARE LICENSE" (Revision 42):
|
||||
.\" <phk@FreeBSD.ORG> wrote this file. As long as you retain this notice you
|
||||
.\" can do whatever you want with this stuff. If we meet some day, and you think
|
||||
.\" this stuff is worth it, you can buy me a beer in return. Poul-Henning Kamp
|
||||
.\" ----------------------------------------------------------------------------
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.\"
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.\"$FreeBSD$
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.\" $FreeBSD$
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.\"
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.Dd April 28, 1999
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.Dd December 12, 2001
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.Dt JAIL 8
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.Os
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.Sh NAME
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.Nm jail
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.Nd imprison process and its descendants
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.Nd "imprison process and its descendants"
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.Sh SYNOPSIS
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.Nm
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.Ar path
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.Ar hostname
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.Ar ip-number
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.Ar command
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.Ar ...
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.Ar path hostname ip-number command ...
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.Sh DESCRIPTION
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The
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.Nm
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@ -55,40 +51,44 @@ Please see the
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.Xr jail 2
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man page for further details.
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.Sh EXAMPLES
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.Ss Setting up a Jail Directory Tree
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.Ss "Setting up a Jail Directory Tree"
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This shows how to setup a jail directory tree:
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.Bd -literal
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D=/here/is/the/jail
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cd /usr/src
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make world DESTDIR=$D
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cd etc
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make distribution DESTDIR=$D NO_MAKEDEV_RUN=yes
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make distribution DESTDIR=$D -DNO_MAKEDEV_RUN
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cd $D/dev
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sh MAKEDEV jail
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cd $D
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ln -sf dev/null kernel
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.Ed
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.Ss Setting Up a Jail
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.Ss "Setting Up a Jail"
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Do what was described in
|
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.Sx Setting Up a Jail Directory Tree
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to build the jail directory tree. For the sake of this example, we will
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.Sx "Setting Up a Jail Directory Tree"
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||||
to build the jail directory tree.
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||||
For the sake of this example, we will
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assume you built it in
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.Pa /data/jail/192.168.11.100 ,
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named for the jailed IP address. Substitute below as needed with your
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named for the jailed IP address.
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Substitute below as needed with your
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own directory, IP address, and hostname.
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.Pp
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First, you will want to set up your real system's environment to be
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.Dq jail-friendly .
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For consistency, we will refer to the parent box as the
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.Dq host environment ,
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.Dq "host environment" ,
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and to the jailed virtual machine as the
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.Dq jail environment .
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.Dq "jail environment" .
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||||
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
|
||||
IP addresses for a service. This means changing
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||||
IP addresses for a service.
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This means changing
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.Xr inetd 8
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to only listen on the
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||||
appropriate IP address, and so forth. Add the following to
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appropriate IP address, and so forth.
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Add the following to
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.Pa /etc/rc.conf
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||||
in the host environment:
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.Bd -literal -offset indent
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@ -98,31 +98,39 @@ portmap_enable="NO"
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.Ed
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.Pp
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.Li 192.169.11.23
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is the native IP address for the host system, in this example. Daemons that
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||||
run out of
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||||
is the native IP address for the host system, in this example.
|
||||
Daemons that run out of
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||||
.Xr inetd 8
|
||||
can be easily set to use only the specified host IP address. Other daemons
|
||||
will need to be manually configured--for some this is possible through
|
||||
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
|
||||
the
|
||||
.Xr rc.conf 5
|
||||
flags entries, for others it is not possible without munging
|
||||
the per-application configuration files, or even recompiling. For those
|
||||
the per-application configuration files, or even recompiling.
|
||||
For those
|
||||
applications that cannot specify the IP they run on, it is better to disable
|
||||
them, if possible.
|
||||
.Pp
|
||||
A number of daemons ship with the base system that may have problems when
|
||||
run from outside of a jail in a jail-centric environment. This includes
|
||||
run from outside of a jail in a jail-centric environment.
|
||||
This includes
|
||||
.Xr sendmail 8 ,
|
||||
.Xr named 8 ,
|
||||
and
|
||||
.Xr rpcbind 8 .
|
||||
While sendmail and named can be configured to listen only on a specific
|
||||
While
|
||||
.Xr sendmail 8
|
||||
and
|
||||
.Xr named 8
|
||||
can be configured to listen only on a specific
|
||||
IP using their configuration files, in most cases it is easier to simply
|
||||
run the daemons in jails only, and not in the host environment.
|
||||
Attempting to serve
|
||||
NFS from the host environment may also cause confusion, and cannot be
|
||||
easily reconfigured to use only specific IPs, as some NFS services are
|
||||
hosted directly from the kernel. Any third party network software running
|
||||
hosted directly from the kernel.
|
||||
Any third party network software running
|
||||
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.
|
||||
@ -135,41 +143,53 @@ to a jail, and its sendmail is down, the mail is delivered to the host,
|
||||
etc.)
|
||||
.Pp
|
||||
Start any jails for the first time without configuring the network
|
||||
interface so that you can clean it up a little and set up accounts. As
|
||||
interface so that you can clean it up a little and set up accounts.
|
||||
As
|
||||
with any machine (virtual or not) you will need to set a root password, time
|
||||
zone, etc. Before beginning, you may want to copy
|
||||
zone, etc.
|
||||
Before beginning, you may want to copy
|
||||
.Xr sysinstall 8
|
||||
into the tree so that you can use it to set things up easily. Do this using:
|
||||
into the tree so that you can use it to set things up easily.
|
||||
Do this using:
|
||||
.Bd -literal -offset indent
|
||||
# mkdir /data/jail/192.168.11.100/stand
|
||||
# cp /stand/sysinstall /data/jail/192.168.11.100/stand
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||||
mkdir /data/jail/192.168.11.100/stand
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||||
cp /stand/sysinstall /data/jail/192.168.11.100/stand
|
||||
.Ed
|
||||
.Pp
|
||||
Now start the jail:
|
||||
.Bd -literal -offset indent
|
||||
# jail /data/jail/192.168.11.100 testhostname 192.168.11.100 /bin/sh
|
||||
.Ed
|
||||
.Pp
|
||||
You will end up with a shell prompt, assuming no errors, within the jail. You
|
||||
can now run
|
||||
.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
|
||||
.Pa /stand/sysinstall
|
||||
and do the post-install configuration to set various configuration options,
|
||||
or perform these actions manually by editing rc.conf, etc.
|
||||
or perform these actions manually by editing
|
||||
.Pa /etc/rc.conf ,
|
||||
etc.
|
||||
.Pp
|
||||
.Bl -bullet -offset indent -compact
|
||||
.It
|
||||
Create an empty /etc/fstab to quell startup warnings about missing fstab
|
||||
Create an empty
|
||||
.Pa /etc/fstab
|
||||
to quell startup warnings about missing fstab
|
||||
.It
|
||||
Disable the port mapper (rc.conf: portmap_enable="NO")
|
||||
Disable the port mapper
|
||||
.Pa ( /etc/rc.conf :
|
||||
.Li portmap_enable="NO" )
|
||||
.It
|
||||
Run
|
||||
.Xr newaliases 1
|
||||
to quell sendmail warnings.
|
||||
to quell
|
||||
.Xr sendmail 8
|
||||
warnings.
|
||||
.It
|
||||
Disable interface configuration to quell startup warnings about ifconfig
|
||||
(network_interfaces="")
|
||||
Disable interface configuration to quell startup warnings about
|
||||
.Xr ifconfig 8
|
||||
.Pq Li network_interfaces=""
|
||||
.It
|
||||
Configure /etc/resolv.conf
|
||||
Configure
|
||||
.Pa /etc/resolv.conf
|
||||
so that name resolution within the jail will work correctly
|
||||
.It
|
||||
Set a root password, probably different from the real host system
|
||||
@ -182,25 +202,30 @@ Install any packages that you think the environment requires
|
||||
.El
|
||||
.Pp
|
||||
You may also want to perform any package-specific configuration (web servers,
|
||||
SSH servers, etc), patch up /etc/syslog.conf so it logs as you'd like, etc.
|
||||
SSH servers, etc), patch up
|
||||
.Pa /etc/syslog.conf
|
||||
so it logs as you would like, etc.
|
||||
.Pp
|
||||
Exit from the shell, and the jail will be shut down.
|
||||
.Ss Starting the Jail
|
||||
.Ss "Starting the Jail"
|
||||
You are now ready to restart the jail and bring up the environment with
|
||||
all of its daemons and other programs. To do this, first bring up the
|
||||
all of its daemons and other programs.
|
||||
To do this, first bring up the
|
||||
virtual host interface, and then start the jail's
|
||||
.Pa /etc/rc
|
||||
script from within the jail.
|
||||
.Pp
|
||||
NOTE: If you plan to allow untrusted users to have root access inside the
|
||||
jail, you may wish to consider setting the
|
||||
kern.security.jail.set_hostname_allowed to 0. Please see the management
|
||||
reasons why this is a good idea. If you do decide to set this variable,
|
||||
jail, you may wish to consider setting the
|
||||
.Va kern.security.jail.set_hostname_allowed
|
||||
to 0.
|
||||
Please see the management reasons why this is a good idea.
|
||||
If you do decide to set this variable,
|
||||
it must be set before starting any jails, and once each boot.
|
||||
.Bd -literal -offset indent
|
||||
# ifconfig ed0 inet alias 192.168.11.100 netmask 255.255.255.255
|
||||
# mount -t procfs proc /data/jail/192.168.11.100/proc
|
||||
# jail /data/jail/192.168.11.100 testhostname 192.168.11.100 \\
|
||||
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 \\
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||||
/bin/sh /etc/rc
|
||||
.Ed
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||||
.Pp
|
||||
@ -216,67 +241,74 @@ You should be able to see
|
||||
and other processes running within the jail using
|
||||
.Xr ps 1 ,
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with the
|
||||
.Dq J
|
||||
flag appearing beside jailed processes. You should also be able to
|
||||
telnet to the hostname or IP address of the jailed environment, and log
|
||||
.Ql J
|
||||
flag appearing beside jailed processes.
|
||||
You should also be able to
|
||||
.Xr telnet 1
|
||||
to the hostname or IP address of the jailed environment, and log
|
||||
in using the accounts you created previously.
|
||||
.Ss Managing the jail
|
||||
.Ss "Managing the Jail"
|
||||
Normal machine shutdown commands, such as
|
||||
.Xr halt 8 ,
|
||||
.Xr reboot 8 ,
|
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and
|
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.Xr shutdown 8 ,
|
||||
cannot be used successfully within the jail. To kill all processes in a
|
||||
cannot be used successfully within the jail.
|
||||
To kill all processes in a
|
||||
jail, you may log into the jail and, as root, use one of the following
|
||||
commands, depending on what you want to accomplish:
|
||||
.Pp
|
||||
.Bl -bullet -offset indent -compact
|
||||
.It
|
||||
.Li kill -TERM -1
|
||||
.It
|
||||
.Li kill -KILL -1
|
||||
.El
|
||||
.Bd -literal -offset indent
|
||||
kill -TERM -1
|
||||
kill -KILL -1
|
||||
.Ed
|
||||
.Pp
|
||||
This will send the
|
||||
.Dq TERM
|
||||
.Dv SIGTERM
|
||||
or
|
||||
.Dq KILL
|
||||
signals to all processes in the jail from within the jail. Depending on
|
||||
.Dv SIGKILL
|
||||
signals to all processes in the jail from within the jail.
|
||||
Depending on
|
||||
the intended use of the jail, you may also want to run
|
||||
.Pa /etc/rc.shutdown
|
||||
from within the jail. Currently there is no way to insert new processes
|
||||
from within the jail.
|
||||
Currently there is no way to insert new processes
|
||||
into a jail, so you must first log into the jail before performing these
|
||||
actions.
|
||||
.Pp
|
||||
To kill processes from outside the jail, you must individually identify the
|
||||
PID of each process to be killed. The
|
||||
.Pa /proc/ Ns Va pid Ns Pa /status
|
||||
PID of each process to be killed.
|
||||
The
|
||||
.Pa /proc/ Ns Ar pid Ns Pa /status
|
||||
file contains, as its last field, the hostname of the jail in which the
|
||||
process runs, or
|
||||
.Dq -
|
||||
to indicate that the process is not running within a jail. The
|
||||
.Dq Li -
|
||||
to indicate that the process is not running within a jail.
|
||||
The
|
||||
.Xr ps 1
|
||||
command also shows a
|
||||
.Dq J
|
||||
flag for processes in a jail. However, the hostname for a jail may be, by
|
||||
.Ql J
|
||||
flag for processes in a jail.
|
||||
However, the hostname for a jail may be, by
|
||||
default, modified from within the jail, so the
|
||||
.Pa /proc
|
||||
status entry is unreliable by default. To disable the setting of the hostname
|
||||
status entry is unreliable by default.
|
||||
To disable the setting of the hostname
|
||||
from within a jail, set the
|
||||
.Dq Va kern.security.jail.set_hostname_allowed
|
||||
.Va kern.security.jail.set_hostname_allowed
|
||||
sysctl variable in the host environment to 0, which will affect all jails.
|
||||
You can have this sysctl set each boot using
|
||||
You can have this sysctl set on each boot using
|
||||
.Xr sysctl.conf 5 .
|
||||
Just add the following line to sysctl.conf:
|
||||
.Bd -literal -offset indent
|
||||
kern.security.jail.set_hostname_allowed=0
|
||||
.Ed
|
||||
Just add the following line to
|
||||
.Pa /etc/sysctl.conf :
|
||||
.Pp
|
||||
.Dl kern.security.jail.set_hostname_allowed=0
|
||||
.Pp
|
||||
In a future version of
|
||||
.Fx ,
|
||||
the mechanisms for managing jails will be
|
||||
more refined.
|
||||
.Ss Sysctl MIB Entries
|
||||
.Ss "Sysctl MIB Entries"
|
||||
Certain aspects of the jail containments environment may be modified from
|
||||
the host environment using
|
||||
.Xr sysctl 8
|
||||
@ -284,7 +316,7 @@ MIB variables.
|
||||
Currently, these variables affect all jails on the system, although in
|
||||
the future this functionality may be finer grained.
|
||||
.Bl -tag -width XXX
|
||||
.It kern.security.jail.set_hostname_allowed
|
||||
.It Va kern.security.jail.set_hostname_allowed
|
||||
This MIB entry determines whether or not processes within a jail are
|
||||
allowed to change their hostname via
|
||||
.Xr hostname 1
|
||||
@ -296,7 +328,7 @@ information in
|
||||
.Pa /proc .
|
||||
As such, this should be disabled in environments where privileged access to
|
||||
jails is given out to untrusted parties.
|
||||
.It kern.security.jail.socket_unixiproute_only
|
||||
.It Va kern.security.jail.socket_unixiproute_only
|
||||
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.
|
||||
@ -304,15 +336,16 @@ 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
|
||||
in the following domains:
|
||||
.Dv PF_LOCAL ,
|
||||
.Dv PF_INET ,
|
||||
.Dv PF_LOCAL , PF_INET ,
|
||||
and
|
||||
.Dv PF_ROUTE ,
|
||||
permitting them access to UNIX domain sockets,
|
||||
permitting them access to
|
||||
.Ux
|
||||
domain sockets,
|
||||
IPv4 addresses, and routing sockets.
|
||||
To enable access to other domains, this MIB variable may be set to
|
||||
0.
|
||||
.It kern.security.jail.sysvipc_allowed
|
||||
.It Va kern.security.jail.sysvipc_allowed
|
||||
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
|
||||
@ -345,14 +378,16 @@ The
|
||||
command appeared in
|
||||
.Fx 4.0 .
|
||||
.Sh AUTHORS
|
||||
.An -nosplit
|
||||
The jail feature was written by
|
||||
.An Poul-Henning Kamp
|
||||
for R&D Associates
|
||||
.Dq Li http://www.rndassociates.com/
|
||||
.Pa http://www.rndassociates.com/
|
||||
who contributed it to
|
||||
.Fx .
|
||||
.Pp
|
||||
Robert Watson wrote the extended documentation, found a few bugs, added
|
||||
.An Robert Watson
|
||||
wrote the extended documentation, found a few bugs, added
|
||||
a few new features, and cleaned up the userland jail environment.
|
||||
.Sh BUGS
|
||||
Jail currently lacks strong management functionality, such as the ability
|
||||
@ -362,10 +397,12 @@ specific jail information via
|
||||
as opposed to
|
||||
.Xr procfs 5 .
|
||||
Similarly, it might be a good idea to add an
|
||||
address alias flag such that daemons listening on all IPs (INADDR_ANY)
|
||||
address alias flag such that daemons listening on all IPs
|
||||
.Pq Dv INADDR_ANY
|
||||
will not bind on that address, which would facilitate building a safe
|
||||
host environment such that host daemons do not impose on services offered
|
||||
from within jails. Currently, the simplist answer is to minimize services
|
||||
from within jails.
|
||||
Currently, the simplist answer is to minimize services
|
||||
offered on the host, possibly limiting it to services offered from
|
||||
.Xr inetd 8
|
||||
which is easily configurable.
|
||||
|
Loading…
Reference in New Issue
Block a user