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Ansible Role: firewalld

Add local firewall rules on server via firewalld.
Why another Ansible role to manage firewalld? The role does everything in "offline" mode. Even creating a new service works offline.
So there should be no issues when firewalld starts, and blocks EVERYTHING by default! (Make sure you test in non-production first, I cannot make any guarantees) This supports adding custom firewalld "services" into zones with custom ports. Also can add or remove ports for built-in services provided by firewalld.
Removes unwanted default services from public/internal zone.

Zones: Add IP ranges to Zones. To remove, change state to disabled. If only one IP range needs to be disabled, create a new zone entry for just that IP range.
Services: disable a service will remove it from that zone as specified in the variables. Don't just delete the config to remove it!
Ports: To remove a port, delete it from the config (under port_protocol).

Since VMs could have different interfaces (eth0/eth1 etc.), interfaces aren't managed.

Be careful, this will remove and add firewalld rules on the OS. Use with caution.

firewalld manual: https://firewalld.org/documentation/

Note: Docker and firewalld do not get along. This role has a check enabled to fail this role if the docker service is running or enabled.
For more information about firewalld and Docker:
https://success.docker.com/article/why-am-i-having-network-problems-after-firewalld-is-restarted
https://www.tripwire.com/state-of-security/devops/psa-beware-exposing-ports-docker/
https://docs.docker.com/network/iptables/

Testing

Molecule is used for testing, and all features are tested. Changes are then made a second time and re-tested to be sure everything works.

Distros tested

  • CentOS: 7.6, 7.7, 8.1
  • Fedora 30, 31
  • Arch Linux (firewalld version 0.8.1) - But who would run a bunch of Arch servers..

Dependencies

  • firewalld

Tested with version 0.6.3 (Latest available in CentOS 7)
Tested with version 0.6.6 (Latest available in Fedora 30)
Tested with version 0.7.0 (Latest available in CentOS 8)
Tested with version 0.7.3 (Latest available in Fedora 31)
Tested with version 0.8.1 (Latest available in Arch Linux)

Default Settings

  • Enable debug
debug_enabled_default: false
  • Proxy (Needed when installing required packages if behind a proxy)
proxy_env: []
  • Role disabled by default. Change to true in group_vars or playbook etc
firewalld_managed: false
  • Check if (Docker) service is running or enabled, and fail the role
firewalld_check_problem_service_managed: true
  • Services to check, and fail the role
firewalld_check_problem_service:
  - docker.service
  • Show configuration from variables
firewalld_show_config: false
  • Start firewalld service
firewalld_start: false
  • Install firewalld package
firewalld_managed_pkg: true

User Settings

  • Remove unwanted default services from public zone
firewalld_public_remove_default:
  - mdns
  - samba-client
  • Remove unwanted default services from internal zone
firewalld_internal_remove_default:
  - mdns
  - samba-client
  • Zone Config

Full list of firewalld predefined zones: https://firewalld.org/documentation/zone/predefined-zones.html

firewalld_zone_source:
  - zone: name of predefined zone (ex. internal|public) (Required)
    state: enabled|disabled (Required)
    source:
      - "IP/Subnet" (Required)
  • Service and Port Config
firewalld_custom_service:
  - name: service name (Required)
    zone: public|internal etc (See zone list above) (Required)
    state: enabled (Required)
    description: Description of service (Optional)
    port_protocol: (Required, unless a built-in service except when changing a default port for built-in service)
      - port/protocol (Required, unless a built-in service)

See example for more details.
Get list of build-in services:

firewall-offline-cmd --get-services

Example config file (inventories/dev-env/group_vars/all.yml)

From the example below:
IP ranges will be added/removed from a zone:

  • 192.168.22.64/26 and 192.168.23.64/26 will be added to the zone internal
  • 192.168.32.64/26 and 192.168.33.64/26 will be removed from the zone internal

Custom services will be created with port(s) specified, and added to a zone:

  • app123-public service is created with port/protocol 5000/tcp, and added to zone public.
  • app123-internal service is created with ports/protocol 8080/tcp, 9000/tcp, and added to zone internal.
  • zabbix-agent service (which is a built-in service in firewalld) is not using the default port (10050) since it's not in the config, 10050/tcp is removed. Instead using port/protocol 3333/tcp, and added to zone public. (Note: The port doesn't need to be commented out).
  • openvpn service (which is a built-in service in firewalld) is using the default port/protocol, and added to zone public. Since this service is built-in, you don't need to specify the port. But to be safe, you should still specify it.
---
firewalld_zone_source:
  - zone: internal
    state: enabled
    source:
      - "192.168.22.64/26"
      - "192.168.23.64/26"
  - zone: internal
    state: disabled
    source:
      - "192.168.32.64/26"
      - "192.168.33.64/26"

firewalld_custom_service:
  - name: app123-public
    zone: public
    # state: disabled
    state: enabled
    description: app123 firewall rules for public zone
    port_protocol:
      - 5000/tcp
  - name: app123-internal
    zone: internal
    # state: disabled
    state: enabled
    description: app123 firewall rules for internal zone
    port_protocol:
      - 8080/tcp
      - 9000/tcp
  - name: zabbix-agent
    zone: public
    # state: disabled
    state: enabled
    port_protocol:
      # - 10050/tcp
      - 3333/tcp
  - name: openvpn
    zone: public
    state: enabled

Example Playbook firewalld.yml

---
- hosts: '{{ inventory }}'
  become: yes
  vars:
    # Use this role #RTFM
    # firewalld_managed: true
  roles:
  - firewalld

Usage

By default no tasks will run unless you set firewalld_managed=true. This is by design to prevent accidents by people who don't RTFM.

ansible-playbook firewalld.yml --extra-vars "inventory=centos7 firewalld_managed=true" -i hosts-dev

Skip installing packages (if known already there - speeds up task)

ansible-playbook firewalld.yml --extra-vars "inventory=centos7 firewalld_managed=true" -i hosts --skip-tags=firewalld_pkg_install

Show more verbose output (debug info)

ansible-playbook firewalld.yml --extra-vars "inventory=centos7 firewalld_managed=true debug_enabled_default=true" -i hosts-dev

Start firewalld service at end of role

ansible-playbook firewalld.yml --extra-vars "inventory=centos7 firewalld_managed=true firewalld_start=true" -i hosts-dev

Only show configuration (from variables)

ansible-playbook firewalld.yml --extra-vars "inventory=centos7 firewalld_managed=true firewalld_show_config=true" -i hosts --tags "firewalld_show_config"

firewalld Command Reference

More commands can be found in firewalld documentation: https://firewalld.org/documentation/man-pages/firewall-offline-cmd

Add IPs to a Zone:

firewall-offline-cmd --zone=public --list-all

firewall-offline-cmd --zone=internal --add-source=192.168.22.64/26
firewall-offline-cmd --zone=internal --add-source=192.168.23.64/26

Add custom service to public zone:

firewall-offline-cmd --new-service=app123-public
firewall-offline-cmd --service=app123-public --set-short=app123-public
firewall-offline-cmd --service=app123-public --set-description='app123 fw rules for public zone'
firewall-offline-cmd --service=app123-public --add-port=5000/tcp
firewall-offline-cmd --zone=public --add-service=app123-public

Add custom service to internal zone:

firewall-offline-cmd --new-service=app123-internal
firewall-offline-cmd --service=app123-internal --set-short=app123-internal
firewall-offline-cmd --service=app123-internal --set-description='app123 fw rules for internal zone'
firewall-offline-cmd --service=app123-internal --add-port=8080/tcp
firewall-offline-cmd --service=app123-internal --add-port=9000/tcp
firewall-offline-cmd --zone=internal --add-service=app123-internal

firewall-offline-cmd --zone=internal --list-all

Get list of build-in services:

firewall-offline-cmd --get-services

Misc useful commands:

firewall-cmd --state
firewall-cmd --get-active-zones

firewall-offline-cmd --zone=public --list-all
firewall-offline-cmd --zone=internal --list-all

firewall-offline-cmd --zone=public --list-services
firewall-offline-cmd --zone=internal --list-services

firewall-offline-cmd --info-service=app123-public
firewall-offline-cmd --info-service=app123-internal

firewall-cmd --reload

iptables Command Reference

List iptables that are active:

iptables -nL

nftables Command Reference

List nftables that are active:

nft list tables
nft list ruleset
nft list table inet firewalld
nft list chain inet firewalld filter_IN_public_allow

TODO

  • Get working with firewalld started or stopped
  • Confirm reload everywhere needed: "notify: Reload firewalld"
  • Add more tags to tasks
  • Test this actually works if firewalld service is running and doesn't block traffic to running app
  • Build travis tests for many scenarios
  • Improve/shorten changing/removing a port
  • --diff doesn't show much since using many commands. Show what's going to happen and add pause when is debug enabled?

Author

Ryan Daniels