scripts / FreeIPA

README.md 13.3 KB

FreeIPA Scripts

This repository contains a small collection of scripts written to migrate my existing LDAP/DNS setup (MacOS Server) to FreeIPA 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)

The latest versions, documentation and a bug tracker are available on my GitLab instance

Copyright (c) 2018 Frederik Lindenaar. free for distribution under the GNU General Public License, see below

Contents

This repository contains the following scripts:

  • freeipa-dns.py is a script providing functionality not available in FreeIPA itself to migrate/synchronize and maintain DNS zones in FreeIPA
  • freeipa-letsencrypt.sh 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 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 is a migration script to transfer/synchronize LDAP users to/with FreeIPA

freeipa-dns.py

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 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

freeipa-letsencrypt.sh

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 and antevens' 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.

set-dns-source.sh

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

users2freeipa.py

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 page on migrating NIS passwords and this 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

License

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/.