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https://github.com/tlinden/jaildk
FreeBSD jail development kit
https://github.com/tlinden/jaildk
Last synced: 17 days ago
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FreeBSD jail development kit
- Host: GitHub
- URL: https://github.com/tlinden/jaildk
- Owner: TLINDEN
- License: bsd-2-clause
- Created: 2020-11-06T18:22:30.000Z (about 4 years ago)
- Default Branch: main
- Last Pushed: 2024-10-15T18:40:40.000Z (4 months ago)
- Last Synced: 2024-10-18T00:17:37.757Z (3 months ago)
- Language: Shell
- Size: 149 KB
- Stars: 4
- Watchers: 5
- Forks: 1
- Open Issues: 5
-
Metadata Files:
- Readme: README.md
- License: LICENSE
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## jaildk - a FreeBSD jail development kit v2.0.0
## Breaking Changes
It is not possible to upgrade an existing installation of jaildk using
the builtin `jaildk update` from version 1.x to 2.x!
So, in order to upgrade to the next major version, check out the repo and execute:
```
make
make install JAILDIR=/your/jaildir
```
See below for more details. Starting with 2.0.0 `jaildk update` can be used again.
In addition starting with 2.0.0 the commandlines of the following subcommands changed:
| 1.x | 2.0.0 up |
|---------------------------------------------------------|------------------------------------------------------------|
| `jaildk build [-b ] [-v ]` | `jaildk build -m [-b ] [-v ]` |
| `jaildk install [-r function]` | `jaildk install -m [-r function]` |
| `rc [-r ]` | `rc -m [-r ]` |
| `ipfw ` | `ipfw -m ` |
So, every subcommand supporting a mode parameter needs that parameter
now specified as an argument to the `-m` parameter.
## Introduction
This is the README for the FreeBSD jail utility `jaildk`. It can be
used to build, update, manage and run jails in a versioned environment.
Every jail consists of layers of directories mounted on top of each
other using nullfs mounts. Some of them can be shared among jails,
some are versioned. By using shared and versioned layers of mounts it
is easy to update jails in a new version while the current version is
still running, you can switch back to an older version of a jail.
Most of the layers are mounted read-only for security reasons.
Let's take a look at the layers of a typical running jail built with `jaildk`:
```
1 /jail/base/12.1-RELEASE-p10 /jail/run/db read-only
2 /dev/md12 /jail/run/db/tmp
3 devfs /jail/run/db/dev
4 /jail/log/db-20201026 /jail/run/db/var/log
5 /jail/appl/db-20201026 /jail/run/db/usr/local read-only
6 /jail/etc/db/etc-20201026 /jail/run/db/etc read-only
7 /jail/etc/db/local-etc-20201026 /jail/run/db/usr/local/etc read-only
8 /jail/etc/db/cron-20201026 /jail/run/db/var/cron
9 /jail/home/db/root-20201026 /jail/run/db/root
10 /jail/data/db/mysql-20201026 /jail/run/db/usr/local/data/mysql
11 /backup/db /jail/run/db/var/backups
|
+--- root of the jail
```
As can be easily deduced this is a database jail with the following layers:
1. **base layer**: This is basically the same as a FreeBSD base, which
contains all biinaries, libraries and other files required to boot
up a FreeBSD system. Our base doesn't contain a kernel by default,
but you could add one, required if you want to use the ports
collection and compile `lsof` yourself.
This particular base is based on 12.1-RELEASE-p10, that is, I
created it while I had this release installed and running on the
host system.
2. **tmp layer**: Just a ramdisk for `/tmp`, the size can be tuned.
3. **dev layer**: Contains /dev/null and friends, required by every jail.
4. **log layer**: Here we have our first versioned layer for
`/var/log`. Notice how all other layers are using the same version,
this is done by purpose (but can be changed if you like). The
version is a jail variable (see below) which is being used for all
layers.
5. **application layer**: As you know if you're using FreeBSD, any
additional software, wether installed from a port or as package,
will be installed to `/usr/local`. In our case it contains the
mysql server software, bash and a couple of supporting
utilities. It is being mounted read-only, so no new software can be
installed in the running jail. This might sound annoying at first,
because you can't just install stuff inside the jail anytime you
like. But it forces you to work more disciplined. Once a jail has
been completely built you can be sure, all components match with
each other. Read below how to install or update software in a jail.
6. **/etc layer**: this just contains the normal etc, it is basically
a stripped copy of the host `/etc`. We do not use it at all inside
a jail, but it's required nontheless. There are some exceptions
however, like `/etc/resolv.conf`.
7. **/usr/local/etc layer**: This is the place we configure all
aspects of the jail, all configs reside here (like in our case the
mysql config). It is also being mounted read-only, just like
the etc layer.
8. **cron layer**: A writable mount for the crontabs of users inside
the jail. That way one can modify crontabs with `crontab
-e`. However, if you don't want or need this, just remove the layer
and add cronjobs to `/etc/crontab`.
9. **/root layer**: most of the administrative work inside a jail must
be done as the root user and it would be a pity not to have a
writable history. So, `/root` is mounted writable to add more
comfort.
10. **a data layer**: A versioned data layer which contains the binary
data of our mysql server. This is very jail specific and you have
to add such layers yourself. Variants of such a layer include the
document root of a webserver or the repositories of a git server.
11. **backup layer**: Another custom layer, here we've mounted a
global backup directory of our host which contains all backups.
All layers are configured in a `mount.conf` file specific for each
jail. The one for this jail looks like this:
```
base/$base $name nullfs ro
md $name/tmp mfs rw,nosuid,async 500m 1777
dev $name/dev devfs
log/$name-$version $name/var/log nullfs rw
appl/db-$version $name/usr/local nullfs ro
etc/$name/etc-$version $name/etc nullfs ro
etc/$name/local-etc-$version $name/usr/local/etc nullfs ro
etc/$name/cron-$version $name/var/cron nullfs rw
home/$name/root-$version $name/root nullfs rw
data/$name/mysql-$version $name/usr/local/data/mysql nullfs rw
/backup/db $name/var/backups nullfs rw
```
Now, as you can see, we're using variables here. Those are defined in
the `jail.conf` (not to be confused with `/etc/jail.conf` on the
host!):
```
name=db
version=20201026
base=12.1-RELEASE-p10
```
You might wonder how the other aspects of a jail are configured like
ip addresses, routing, jail parameters, sysctls etc. Well, that's
beyond the purpose of `jaildk`. You just use the standard FreeBSD
mechanism for these things, that is `/ect/rc.conf`, `/etc/jail.conf`,
`service jail ...`, `jexec`, etc. However, `jaildk` provides some
handy wrappers to make live easier.
For an overview of the provided commands, here's the usage screen:
```
Usage: ./jaildk
Building Jails:
base -b [-w] [-s ] - build a new base
build <jail> -m <mode> [-b <base>] [-v <version>] - install a build chroot of a jail
create - create a new jail from a template
clone -s <src> -d <dst> [-o <v>] [-n <v>] - clone an existing jail or jail version
fetchports [-v <version>] - fetch current port collection
(Un)installing Jails:
install <jail> -m <mode> [-r function] - install a jail (prepare mounts, devfs etc)
uninstall <jail> [-w] - uninstall a jail
remove <jail> - remove a jail or a jail version
reinstall <jail> [-b <base>] [-v <version>] - stop, remove, install and start a jail, if
-b and/or -v is set, update the jail config
prune [-b | -a | -j <jail> - display unused directories
Maintaining Jails:
start <jail> - start a jail
stop <jail> - stop a jail
restart <jail> - restart a jail
status [<jail>] [-v] - display status of jails or <jail>
rc <jail> -m <mode> [-r <rc.d script>] - execute an rc-script inside a jail
ipfw <jail> -m <mode> - add or remove ipfw rules
Managing Jails:
login <jail> [<user>] - login into a jail
blogin <jail> - chroot into a build jail
Transferring Jails:
freeze <jail> [-a -b -v <version>] - freeze (build an image of) a jail
thaw <image> - thaw (install) an image of a jail
Getting help and internals:
completion - print completion code. to use execute in a bash:
source <(jaildk completion)
help <command> - request help on <command>
version - print program version
update [-f] - update jaildk from git repository
```
## Installation
Clone this repository to your FreeBSD server and execute the following command:
```
make
make install
```
This will create the directory structure required for the tool itself,
create a template jail and build a base directory. The default base
directory is `/jail`. You can modify this by issuing:
```
make install JAILDIR=/another/dir
```
Be aware, that the `jaildk` script itself will only be installed to
`$JAILDIR/bin/jaildk`. Either put this directory into your `$PATH`
variable or create a symlink to the script in some bin dir.
## Bash Completion
If you want to use `jaildk` with bash completion, put this line into your `.bashrc`:
```
source <(jaildk completion)
```
## Basic usage
Let's say you installed *jaildk* into `/jail` and you want to create a
new jail with the name 'myjail' and the ip address '172.16.1.1'.
The following steps need to be done:
### Configure /etc/jail.conf
Create the file `/etc/jail.conf` with the following innitial contents:
```
* {
exec.start = "/bin/sh /etc/rc";
exec.stop = "/bin/sh /etc/rc.shutdown";
allow.raw_sockets = "false";
sysvmsg = "new";
sysvsem = "new";
sysvshm = "new";
host.hostname = $name;
path = "/jail/run/$name";
exec.prestart = "/jail/bin/jaildk install $name start";
exec.clean = "true";
}
myjail {
ip4.addr = "172.16.1.1";
}
```
Refer to [jail(8)](https://www.freebsd.org/cgi/man.cgi?query=jail&sektion=8) for more possible settings.
### Configure /etc/rc.conf
Next add the following lines to your `/etc/rc.conf`:
```
ifconfig_em0_alias0="inet 172.16.1.1/32"
jail_enable="YES"
```
You may need to replace the interface name `em0` with the one in use on your system.
You might need to restart the interface to apply the alias: `/etc/rc.d/netif restart`.
### Create the jail
```
# jaildk create myjail
- cpdup -x /jail/log/.template-20201106 /jail/test/log/myjail-20201106
- cpdup -x /jail/home/.template/root-20201106 /jail/test/home/myjail/root-20201106
- cpdup -x /jail/etc/.template/etc-20201106 /jail/test/etc/myjail/etc-20201106
- cpdup -x /jail/etc/.template/local-etc-20201106 /jail/test/etc/myjail/local-etc-20201106
/jail/data/.template/www doesn't exist, ignored
/jail/data/.template/spool doesn't exist, ignored
- cp -pRp /jail/etc/.template/mount.conf /jail/test/etc/.template/ports.conf /jail/test/etc/.template/mtree.conf /jail/test/etc/myjail/
cp: /jail/etc/.template/ports.conf: No such file or directory
Creating /jail/etc/.template/jail.conf
Creating run and build dirs
- mkdir -p /jail/run/myjail
- mkdir -p /jail/build/myjail
DONE.
Consider adding the jail myjail to /etc/jail.conf!
To mount the build chroot of the new jail, execute:
jaildk build myjail
To login into the build chroot
jaildk blogin myjail
To mount the production chroot of the new jail, execute:
jaildk install myjail
To login into the build chroot
jaildk login myjail
To start the jail, execute:
jaildk start myjail
```
### Mount the build chroot of the jail
```
# jaildk build myjail
Installing jail myjail
mount - mount -t nullfs -o rw /jail/base/12.1-RELEASE-p10 /jail/build/myjail
mount - mdmfs -o rw,nosuid,async -s 128m -p 1777 md /jail/build/myjail/tmp
mount - mount -t devfs dev /jail/build/myjail/dev
mount - mount -t nullfs -o rw /jail/log/myjail-20201106 /jail/build/myjail/var/log
mount - mount -t nullfs -o rw /jail/appl/default-20201106 /jail/build/myjail/usr/local
mount - mount -t nullfs -o rw /jail/etc/myjail/etc-20201106 /jail/build/myjail/etc
mount - mount -t nullfs -o rw /jail/etc/myjail/local-etc-20201106 /jail/build/myjail/usr/local/etc
mount - mount -t nullfs -o rw /jail/home/myjail/root-20201106 /jail/build/myjail/root
```
### Chroot into the build dir and install software
```
jaildk blogin myjail
pkg install bash nginx curl ...
vi /usr/local/etc/rc.conf
vi /usr/local/etc/nginx/nginx.conf
```
Since the build chroot is writable you can install packages and
configure everything as needed.
### Using the ports collection
There might be cases when using pre build binary packages are not your
thing. In such a case you want to use the [FreeBSD Ports Collection](https://www.freebsd.org/ports/).
*jaildk* supports this, here are the steps required:
#### Create a buildbase
A normal base directory cannot be used with the ports collection
because jaildk removes libraries and binaries for security reasons
from normal bases. To create a build base, execute:
`jaildk base -b 12-RELEASE-build -w`
Next, add the following entry to the configuration of you jail. To
stay with our example, edit `/jail/etc/myjail/jail.conf` and add:
`buildbase=12-RELEASE-build`
Then install the build jail as usual:
`jaildk build myjail`
Install the current ports collection:
`jaildk fetch`
In case the ports version created does not match the version of your
jail, you need to configure the different ports version in your jail
config `/jail/etc/myjail/jail.conf` like this:
`ports=20201127`
Now you can enter the build jail and install ports the traditional way:
```
jaildk blogin myjail
cd /usr/ports/shells/bash
make config-recursive install clean
```
### When done, install and start the jail
```
# jaildk install myjail
Installing jail myjail
mount - mount -t nullfs -o ro /jail/base/12.1-RELEASE-p10 /jail/run/myjail
mount - mdmfs -o rw,nosuid,async -s 128m -p 1777 md /jail/run/myjail/tmp
mount - mount -t devfs dev /jail/run/myjail/dev
mount - mount -t nullfs -o rw /jail/log/myjail-20201106 /jail/run/myjail/var/log
mount - mount -t nullfs -o ro /jail/appl/default-20201106 /jail/run/myjail/usr/local
mount - mount -t nullfs -o ro /jail/etc/myjail/etc-20201106 /jail/run/myjail/etc
mount - mount -t nullfs -o ro /jail/etc/myjail/local-etc-20201106 /jail/run/myjail/usr/local/etc
mount - mount -t nullfs -o rw /jail/home/myjail/root-20201106 /jail/run/myjail/root
# jaildk start myjail
Jail myjail start:
Starting jails: myjail.
# jaildk status myjail
Jail scipown status:
JID IP Address Hostname Path
myjail 172.16.1.1 myjail /jail/run/myjail
Jail myjail rc status:
syslogd is running as pid 28180.
cron is running as pid 52130.
php_fpm is running as pid 45558.
nginx is running as pid 63975.
===> fcgiwrap profile: mediawiki
fcgiwrap is running as pid 37682.
```
### Login into the running jail for administration
```
# jaildk login myjail
```
You can use this to login into a database or execute commands inside the jail.
### Updating a jail
The very first thing to do is to update the host system using `freebsd-update`.
Next create a new base version:
```
jaildk base -b `uname -r`
```
But of course you can update a jail with the current base as well.
Now you can clone of your jail with a new version:
```
jaildk clone -s myjail -d myjail -o 20201106 -n 20210422
```
Mount the build chroot for the new version:
```
jaildk build myjail -m start -b `uname -r` -v 20210422
```
And finally chroot into the new jail and update it:
```
jaildk blogin myjail
pkg update
...
```
The last step is to remove the current running jail, change the
version in `etc/myjail.conf`, install and start the new version. This
can be easily done with the following command:
```
jaildk reinstall myjail -b `uname -r` -v 20210422
```
This command also creates a copy of the current jail.conf.
If there's anything wrong you can always go back to the previous
version using the following command (using the previous base and version):
```
jaildk reinstall myjail -b 12.2-RELEASE-p1 -v 20201106
```
## Advanced Features
Jaildk also offers some advanced features like automatically setting
up and deleting ipfw rules or freezing and thawing a jail (to make it
easily portable).
### Using the IPFW
To use the IPFW on your host you first have to enable ipfw in your
hosts rc.conf `firewall_enable="YES"`. You probably want to set the
default firewalling-type there aswell, check out the
[FreeBSD handbook](https://www.freebsd.org/doc/handbook/firewalls-ipfw.html)
for further information.
Once enabled you also need to start ipfw by executing the rc script:
`/etc/rc.d/ipfw start`.
Be aware that inter-jail communication is transfered via the loopback
interface (normally lo0) for which there is a high priority allow any
to any rule by default:
`allow ip from any to any via lo`
In order to control the inter-jail communication you have to delete
this rule first.
If an ipfw.conf exists for a jail (e.g. /jail/etc/myjail/ipfw.conf)
the rules inside that config file are added when starting, and deleted
when stopping the jail. E.g. allowing HTTP/HTTPS traffic for that
jail (webserver):
`allow tcp from any to $ip setup keep-state`
As demonstrated in the previous rule `$ip` is reserved and
automatically replaced with the jails own ip (as reported by
`jls`). The same applies to the ipv6 address which will be available
as variable `$ip6`. Also, all variables in the jails `jail.conf` can
be used.
In order to make these ipfw rules available on boot, you need to add
the following line to `/etc/jail.conf` in the section of the jail
which uses custom ipfw rules:
`exec.prestart = "/jail/bin/jaildk ipfw $name"`
Be aware, that the ipfw module will only be executed if the jail is
running so that we can properly determine the ip addresses of the
running jail. **Note**: this might change in the future.
### Using pf
Beside ipfw, Free supports
[pf](https://www.freebsd.org/doc/de_DE.ISO8859-1/books/handbook/firewalls-pf.html)
as well. You can use pf with `jaildk`. Unlike the ipfw module (see
above) it is a normal `install` module. That is it can be installed or
reloaded before the jail is running (i.e. like the mount module).
In order to use `pf` with a jail, enable and configure it according to
the FreeBSD handbook linked above. It is recommended to include
general block, scrup, state rules, communication to and fro localhost
etc and just leave everything which is related to your jail.
Just so that you know how such a global `/etc/pf.conf` file might look
like, here's a simple one:
```shell
# variables
ext = "em0"
me = "your ipv4 address here"
me5 = "your ipv6 address here/64"
loginports = "{ 22, 5222, 443 }"
icmp_types = "echoreq"
# tables. look at the contents of a table:
# pfctl -t bad_hosts -T show
# remove an entry from a table:
# pfctl -t bad_hosts -T delete $ip
table <bad_hosts> persist
# default policy
set block-policy drop
# optimize according to rfc's
set optimization aggressive
# normalisation
scrub in all
antispoof for $ext
# allow localhost
pass quick on $local
# additional default block rules w/ logging. to view the log:
# tcpdump -n -e -ttt -r /var/log/pflog
# to view live log:
# tcpdump -n -e -ttt -i pflog0
block in log on $ext
block in log on $ext inet6
# whoever makes it into those tables: you loose
block quick from <bad_hosts>
# allow outgoing established sessions
pass out keep state
pass out inet6 keep state
# allow troubleshooting
pass in on $ext inet proto icmp all icmp-type $icmp_types keep state
pass in on $ext inet proto udp from any to any port 33433 >< 33626 keep state
# allow all icmpv6
pass in quick inet6 proto icmp6 all keep state
# allow login but punish offenders
block quick from <bad*hosts>
pass in quick on $ext inet proto tcp from any to $me port $loginports \
flags S/SAFR keep state \
(max-src-conn-rate 10/60, \
overload <bad*hosts> flush global) label ServicesTCP
pass in quick on $ext inet6 proto tcp from any to $me6 port $loginports \
flags S/SAFR keep state \
(max-src-conn-rate 10/60, \
overload <bad_hosts> flush global) label ServicesTCP
```
Install the ruleset with `service pf start`.
Now that everything is prepared you can create a `/jail/etc/myjail/pf.conf` file for your
jail. Here's an example I use for a webserver jail, which includes a
git server:
```shell
ip = "jail ip4 addr"
ip6 = "jail ip6 addr"
loginports = "{ 22 }"
prodports = "{ 80, 443 }"
ext = "em0"
# dynamic block list
table <blocked>
# restrict foreigners
block quick from <blocked>
pass in quick on $ext inet proto tcp from any to $ip port $loginports \
flags S/SAFR keep state \
(max-src-conn-rate 10/60, \
overload <blocked> flush global) label ServicesTCP
# allow production traffic v4
pass in quick on $ext proto tcp from any to $ip port $prodports keep state
# allow production traffic v6
pass in quick inet6 proto tcp from any to $ip6 port $prodports keep state
```
That's it already. Now install the jail as usual. You can also install
the pf ruleset for the jail separately:
`jaildk install myjail -m start -r pf`
To take look at the rules, execute:
`jaildk install myjail -m status -r pf`
You can of course manipulate the ruleset manually. `jaildk` installs
rulesets into a jail specific anchor using the following naming
scheme: `/jail/<jail name>`. So, for example to view the rules, execute:
`pfctl -a /jail/myjail -s rules`
Manipulate a jail specific table:
`pfctl -a /jail/myjail -t blocked -T show`
## Getting help
Although I'm happy to hear from jaildk users in private email,
that's the best way for me to forget to do something.
In order to report a bug, unexpected behavior, feature requests
or to submit a patch, please open an issue on github:
https://github.com/TLINDEN/jaildk/issues.
## Copyright and license
This software is licensed under the BSD license.
## Authors
T.v.Dein <tom AT vondein DOT org>
F.Sass (Culsu)
## Project homepage
https://github.com/TLINDEN/jaildk