scripts / FreeIPA

FreeIPA Scripts
===============
This repository contains a small collection of scripts written to migrate my
existing LDAP/DNS setup (MacOS Server) to [FreeIPA](https://www.freeipa.org)
and manage my setup afterwards. These scripts provide functionality unavailable
in the FreeIPA command line tools. They use the FreeIPA API as much as possible
as I didn't like the provided alternatives for migration to directly update the
FreeIPA LDAP database. Most of these script / commands are meant to synchronize
between an existing situation and FreeIPA and are safe to run multiple times.
As side-effect, this also makes them suitable to support a gradual migration
over time (where a source system is still in production until final cut-over)

Please note that these scripts are intended to run on the FreeIPA server and
require a valid (admin) kerberos ticket, which can be obtained with:
```
kinit admin
```

The latest versions, documentation and a bug tracker are available on my
[GitLab instance](https://gitlab.lindenaar.net/scripts/freeipa)

Copyright (c) 2018 - 2019 Frederik Lindenaar. free for distribution under the
GNU General Public License, see [below](#license)

Contents
========
This repository contains the following scripts:
  * [freeipa-dns.py](#freeipadns)
    is a script providing functionality not available in FreeIPA itself to
    migrate/synchronize and maintain DNS zones in FreeIPA

  * [freeipa-letsencrypt.sh](#freeipaletsencrypt)
    is a script to setup and configure Certbot and FreeIPA to request and renew
    use publicly verifiable Let's Encrypt certificate(s)

  * [set-dns-source.sh](#setdnssource)
    enforce the source address of outgoing DNS messages using firewalld as work
    around for bind-dyndb-ldap plugin not supporting bind's ```notify-source```
  * [users2freeipa.py](#users2freeipa)
    is a migration script to transfer/synchronize LDAP users to/with FreeIPA

  * [freeipa-service-password.sh](#freeipaservicepassword)
    is a script to create a service account and (re)set it's password
  * [freeipa-service-ntlm.sh](#freeipaservicentlm)
    is a script to grant a service account access to NTLM password attributes
  * [freeipa-samba-user.sh](freeipasambauser)
    is a script to extend users to a sambaSAMAccount for Samba compatibility

<a name=freeipadns>freeipa-dns.py</a>

-------------------------------------

This script provides functionality not provided by FreeIPA to migrate and/or
synchronize / maintain DNS data in FreeIPA. Currently the following commands
are implemented:

  * axfr - synchronize DNS zone(s) using a zone-xfer. Contrary to the suggested
    [migration approach](https://docs.pagure.org/bind-dyndb-ldap/Migration.html)
    this uses the FreeIPA API to migrate or synchronize DNS zones with FreeIPA
    so it can also be used for running things in parallel or gradual migrations.

    for example, to migrate / synchronize fromain ```domain.tld``` from DNS
    server ```192.168.1.53``` without checking DNS overlap, issue the command:

    ~~~
    ./freeipa-dns.py -v axfr -T 172.1.2.53 -n -f none 192.168.1.53 domain.tld
    ~~~

    in addition, this will ensure zone-xfers are allowed from ```172.1.2.53```
    and disable forwarding in FreeIPA.

  * copy - copy a DNS record in FreeIPA within or between zones
    for example, to copy ```A``` and ```AAAA``` from host ```wwww.domain.tld```
    to the domain ```domain.tld``` itself, issue the command:

    ~~~
    ./freeipa-dns.py -v copy -l A AAAA wwww.domain.tld -T domain.tld
    ~~~

  * move - move a DNS record in FreeIPA from one one to another
    for example, to move ```host1.int``` in zone ```domain.tld``` to ```host```
    in zone ```int.domain.tld``` issue the command:

    ~~~
    ./freeipa-dns.py -v move -z domain.tld host.int host.int.domain.tld
    ~~~

  * serial - update (set) zone serial(s) in FreeIPA, supporting both RFC1912
    style serials (YYYYMMDD##) based on current date and setting the serial to
    a specific value. To set the serial of a zone to revision 2 of today for
    zones ```zone1.mydomain.tld``` and ```zone2.mydomain.tld```, run:

    ~~~~
    ./freeipa-dns.py -v serial -t 2 zone1.mydomain.tld zone2.mydomain.tld
    ~~~~

    by default this command will set the serial to a larger value (which can be
    overridden with the ```-f```/```--force``` flag)

  * generate - generate number-range DNS records/attributes in FreeIPA
    This is meant to generate series of hosts or attributes, for example, to
    generate hosts ```dhcp-01``` to ```dhcp-10``` in zone ```int.mydomain.tld```
    with ip addresses starting from ```192.168.2.100``` issue to command:

    ~~~
    ./freeipa-dns.py -v generate int.mydomain.tld dhcp-%02d -4 192.168.2.100 \
                     --auto-increment-a -n 5
    ~~~

    it can also be used to generate a farm of web servers in different subnets
    with the command:

    ~~~
    ./freeipa-dns.py -v generate int.mydomain.tld www -4 192.168.%d.80 -n 5
    ~~~

  * reverse-ptr - create/update reverse DNS (PTR) entries in FreeIPA
    With this command reverse-zones can be automatically maintained. it scans
    the zones in FreeIPA for ```A``` and ```AAAA``` records and creates the
    corresponding records in the ```in-addr.arpa``` and ```ip6.arpa``` zones.
    The reverse zones must exist, and can also be created with this command by:

    ~~~
    ./freeipa-dns.py -v reverse-ptr -n -p -c 10. 10.100 192.168 2001:0db8:85a3
    ~~~

    which will create the reverse zones for prefixes 10.* 10.100.* 192.168.*
    and ipv6 prefix 2001:0db8:85a3. Reverse (PTR) records will automatically be
    created in the correct zone with the following command:

    ~~~
    ./freeipa-dns.py -v reverse-ptr -a
    ~~~

    by default, the command will not overwrite existing records, (which can be
    overridden with the ```-o```/```--override``` flag). To force a PTR record
    to point to a specific host, e.g. ```www.mydomain.tld``` run the command:

    ~~~
    ./freeipa-dns.py -v reverse-ptr -o -z mydomain.tld -H www
    ~~~

for available commands run ```freeipa-dns.py -h``` and to get an overview of
the available options for each commmand run ```freeipa-dns.py <command> -h```

<a name=freeipaletsencrypt>freeipa-letsencrypt.sh</a>

-----------------------------------------------------

This script will ensure the necessary setup is in place so that Certbot (EFF's
certificate request script for Let's Encrypt) will work with FreeIPA for DNS
challenges and and instructs it to deploy new certificates for FreeIPA's web
interface. Before writing this script I looked at available options, especially

[freeipa-letsencrypt](https://github.com/freeipa/freeipa-letsencrypt) and
[antevens'](https://github.com/antevens/letsencrypt-freeipa) implementation but

decided to take a slightly different approach where Certbot does all the work
and the setup script will only ensure that the environment is prepared and that
Certbot is initially instructed correctly. This allows to fully tie-in with how
Certbot handles renews and use the Certbot package's provided method to schedule
these.

The following changes will be made for this:
  1. Add Let's Encrypt Root and Intermediate CAs as trusted CAs
  2. Create DNS Administrator role in FreeIPA that can edit any DNS Record
  3. Create host service: ${SERVICE}
  4. Allow letsencrypt host service to manage DNS entries
  5. Register with Let's encrypt as: ${EMAIL}
  6. Request a Let's Encrypt SSL certificate for: ${CERTNAME}
     with DNS Alternative names: ${DNSALTNAMES}
  7. install the Let's Encrypt certificate in apache as host SSL certificate,
     storing renewal config in: /etc/letsencrypt/renewal/$HOSTNAME.conf
  8. configure the Fedora Certbot renew timer so that certbot is run daily to
     renew the certificate when needed.

The script is built to auto-configure but many of the defaults can be overridden
by setting one of the following environment variables:

| Variable    | Description                        | Default value             |
|-------------|------------------------------------|---------------------------|

| CERTNAME    | certificate hostname,              | host's canonicalname  (1) |
| DNSALTNAMES | certificate DNS names              | host's principalnames (1) |

| DOMAIN      | Let's Encrypt challenge DNS zone   | {DNS name's domain}  (2)  |

| EMAIL       | administrator's e-mail address     | hostmaster@{domain}       |
| HOSTNAME    | FreeIPA server's hostname          | `hostname --fqdn`         |
| KEYTAB      | Let'sEncrypt service's keytab file | /etc/letsencrypt/keytab   |
| KRB5CCNAME  | Kerberos5 cache to use for tickets | automatically determined  |
| REPLY       | when 'y' skip user confirmation    | ""                        |
| SERVICE     | FreeIPA service for Certbot to use | letsencrypt/canonicalname |
| SUDO        | command to become root (if needed) | sudo                      |
| TMPDIR      | Directory for temporary files      | /tmp                      |

(1)  obtained from the FreeIPA server record looked up based on ${HOSTNAME}
(2) this allows to enforce the DNS zone, e.g. host.subdomain in mydomain.tld

When things change, the script can simply be run again.

<a name=setdnssource>set-dns-source.sh</a>
------------------------------------------
FreeIPA's bind-dyndb-ldap plugin does not support bind's ```notify-source```
settings and simply uses the main address when sending DNS notifications. This
breaks multi-homed setups and, in case of IPv6, even causes bind to send NOTIFY
messages from the temporary IPv6 address, causing slave servers to reject them.
This script will setup Source NAT in firewalld to enforce the IPv4/IPv6 address
of outgoing DNS packets to ensure that DNS NOTIFYs messages will use the correct
source IPv4/IPv6 address. The IPv4/IPv6 address(es) to enforce should either be
provided in the environment or changed at the top of the script. In case an IPv4
address is provided, the script can figure out itself which device to use when
running it, if not this should be provided as well. To install run:
~~~
sudo IPV4ADDR=192.168.0.100 IPV6ADDR=none ./set-dns-source.sh install
~~~
to remove installed rules, run with the same parameters and parameter 'remove':
~~~
sudo IPV4ADDR=192.168.0.100 IPV6ADDR=none ./set-dns-source.sh remove
~~~
and to see custom rules run: ```sudo firewall-cmd --direct --get-all-rules```



<a name=users2freeipa>users2freeipa.py</a>
------------------------------------------
This script uses LDAP to obtain users from a MacOS Server (or other LDAP)
server and synchronizes the results with the users registered in FreeIPA.
Since it synchronizes data it is safe to run multiple times and users can be
imported also as stage users initially.

The intent is to migrate user data and to not drag on a legacy setup. For
this reason, the script will create new user and group IDs and not copy homedir
and shell information by default. For the IDs, the legacy information can be
stored in an FreeIPA ID View so it remains available, other items can be copied
over using command line options. Passwords can be copied-over (if available in
a usable format), and the script also supports having FreeIPA generate random
passwords and store these in a file for further processing/sharing with users.

Users can be copied from an existing (generic) LDAP database and a MacOS Server
OpenDirectory-flavor LDAP server. In this case, additional information (e.g.
Apple's generatedUID) will be copied over as well. Please note that this does
require customizing the FreeIPA LDAP schema, which the script will check for
and can install (option ```-U```). As the setup is modular it should be easy
to tweak or add other migrations.

By default all users will be migrated/synchronized, but it is also possible to
limit this to specific user(s) or group(s) or specifically exclude specific
users or groups. An example to copy all users in the group ```workgroup```
except ```admin``` from an Apple MacOS OpenDirectory server:
~~~
./users2freeipa.py -v -O -U -c "Legacy LDAP" -g workgroup -x admin -G \
                   -P -p passwords.txt ldap://ldap.mydomain.tld
~~~
This will also install the OpenDirectory-specific schema customization, create
groups and copy group memberships, copy usuable passwords and ensure that all
users have a password (storing generated passwords to ```passwords.txt```)

Please note that migrating existing passwords from LDAP has limitations, see
[this](https://www.freeipa.org/page/NIS_accounts_migration_preserving_Passwords)
page on migrating NIS passwords and [this](https://pagure.io/freeipa/issue/4732)
issue reported with it. Bottom line is that (at this moment) password migration
is flawed and always will require manual action from the user. For this reason
the better alternative to set a random password and ask the user to reset the
password using the FreeIPA portal makes more sense.

Before running a production user migration, it is important to have FreeIPA
setup and configured correctly so that the right defaults are used for new
users. Best is to start with a single user and add that as a stage user (please
note that this will not yet assign userIDs, group memberships and a password
as FreeIPA does not yet support that) and use an ID View to store legacy data.

For all available command-line options, run ```users2freeipa.py -h```

<a name=freeipaservicepassword>freeipa-service-password.sh</a>
--------------------------------------------------------------
This script sets up a service under a host (creating both if needed) so that it
can use an LDAP simple bind for authentication. Although it is straightforward
to setup a host and service account in FreeIPA using the web interface, this
will not allow it to perform an LDAP simple bind (without requiring Kerberos).
For this, a direct change to the LDAP database is required to extend the service
principal object and make it an ```simpleSecurityObject``` with a password. This
script accepts a hostname and one or more services and should be run like:
~~~
./freeipa-service-password.sh <hostname> <service> [<service>]
~~~

As it always sets the password this script can be used for initial setup as well
as a reset of a service password. It performs the following actions:
  * Creates the host in FreeIPA (if it does not exists)
    When creating a new host it scans its SSH key and stores this in FreeIPA
  * Creates each service under the host in FreeIPA (if it does not exists)
  * (Re)sets each service’s LDAP password to a long generated random password

When done it prints the services bind DN and generated password for later use.


<a name=freeipaservicentlm>freeipa-service-ntlm.sh</a>
------------------------------------------------------
This script grants a service under a host access to the LDAP attributes required
to perform NLTM authentication. It sets up the necessary privilege, permission
and a role to grant the rights (if necessary) and then assigns the role to the
service on the host as specified on the command line. for this to work, Active
Directory domain trust support must have been enabled with the command:
~~~
sudo ipa-adtrust-install --add-sid
~~~
(the ```--addsid``` parameter is required to convert existing users).

Please note that for the necessary attributes to become available, users *must*
change their password after enabling Active Directoy domain support as FreeIPA
only maintains the necessary attributes after the user object has been modified.

Running this command will make the ```ipNTHash``` attribute available with the
necessary hash to perform NTLM authentication. Depending on whether the client
implementation supports mapping the attribute it is sufficient to configure it
to use this attribute or require to migrate users to the Samba schema with
[freeipa-samba-user.sh](freeipasambauser). To use the script execute:
~~~
./freeipa-service-ntlm.sh <hostname> <service> [<service>]
~~~
The specified service principals must already exist (they can be created using
[freeipa-service-password.sh](#freeipaservicepassword) or manually).

The script is built to auto-configure though some settings can be overridden by
setting one of the following environment variables:

| Variable  | Description             | Default value                          |
|-----------|-------------------------|----------------------------------------|
| HOST      | Service host hostname   | 1st command line parameter             |
| HOSTNAME  | FreeIPA server hostname | `hostname --fqdn`                      |
| PERM_NAME | Name of permission      | Read Samba NTLM RC4 Password Hash attribute |
| PRIV_NAME | Name of privilege       | Samba (NTLM) RC4 Password Hash Access  |
| ROLE_NAME | Name of role            | Samba/NTLM Authenticator               |

The description of the privilege / role creates can be changed through:
| Variable       | Default value                                               |
|----------------|-------------------------------------------------------------|
|PRIV_DESCRIPTION|Perform Samba NTLM authentication using the RC4 password Hash|
|ROLE_DESCRIPTION|Perform Samba (NTLM) Authentication using the RC4 Password hash|


<a name=freeipasambauser>freeipa-samba-user.sh</a>
--------------------------------------------------
This script adds the ```sambaSAMAccount``` objectclass to specified users so
that they can with Samba / NTLM. For everything to work, the Samba server must
login with a service account that has a simple password (setup with
[freeipa-service-password.sh](#freeipaservicepassword)) with access to the NTLM
password attributes (setup with [freeipa-service-ntlm.sh](#freeipaservicentlm)).
This script was written to support integration with Synology DSM (see also this
[blog post](https://frederik.lindenaar.nl/2019/07/14/integrating-synology-ds-with-freeipa.html))
but should also work for other Samba servers (please raise an issue in case it
doesn't work). I found that FreeIPA will maintain and expose required attributes
for NTLM authentication (```sambaNTPassword``` and ```sambaPwdLastSet```) when
Active Directory domain trust support has been enabled with the command:
~~~
sudo ipa-adtrust-install --add-sid
~~~
(the ```--addsid``` parameter is required to convert existing users).

To use the script to migrate all users (except admin) run (the backslash is
needed to avoid shell expansion of * as parameter):
~~~
./freeipa-service-password.sh \*
~~~

Besides a single * the script also accepts the login of one or more users to
migrate as parameter. To explicitly migrate admin - excluded with * - run:
~~~
./freeipa-samba-user.sh admin
~~~

The script will only migrate users that are not yet a ```sambaSAMAccount``` so
it can be run safely multiple times or at set intervals from cron (additional
work is required to make that work though as it will need a valid Kerberos
ticket from a keytab file for that).

Please note that for the necessary attributes to become available, users *must*
change their password after being converted ```sambaSAMAccount``` as FreeIPA
only maintains the necessary attributes after the user object has been modified.

The script is built to auto-configure though some settings can be overridden by
setting one of the following environment variables:

| Variable    | Description                        | Default value             |
|-------------|------------------------------------|---------------------------|
| HOST        | Service host hostname              | 1st command line parameter|
| HOSTNAME    | FreeIPA server's hostname          | `hostname --fqdn`         |
| SAMBADOMAIN | Samba (Windows) domain name        | FreeIPA Kerberos realm    |

<a name="license">License</a>
-----------------------------
These scripts, documentation & configration examples are free software: you can
redistribute and/or modify it under the terms of the GNU General Public License
as published by the Free Software Foundation, either version 3 of the License,
or (at your option) any later version.

This script, documenatation and configuration examples are distributed in the
hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied
warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
General Public License for more details.

You should have received a copy of the GNU General Public License along with
this program.  If not, download it from <http://www.gnu.org/licenses/>.