Merge pull request #100 from corvus-migratorius/fail2ban-rhel

Prototype a role for installing `fail2ban` on RHEL 9+

roles/fail2ban_rhel/README.md

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+fail2ban_rhel
+=============
+
+A small role to deploy `fail2ban` on RHEL/Rocky 9+ hosts. Currently supports only a templated `sshd` jail.
+
+Requirements
+------------
+
+- Target hosts must be RHEL-family or Rocky Linux 9+
+
+Supported Platforms
+-------------------
+
+- RHEL 9+
+- Rocky Linux 9+
+
+Role Variables
+--------------
+
+sshd jail configuration
+
+- `fail2ban_rhel_jail_sshd`:
+    `enabled`: enable the sshd jail. Default: `true`
+    `port`: fail2ban port for sshd. Default: `ssh`
+    `logpath`: path to the SSH log file. Default: `/var/log/secure`
+    `findtime`: time window for fail2ban. Default: `600`
+    `maxretry`: maximum retry count. Default: `5`
+    `bantime`: ban duration in seconds. Default: `600`
+    `ignoreips`: list of IPs and CIDRs that fail2ban should ignore. Default: `127.0.0.1/8`, `::1`
+
+Behavior
+--------
+
+By default this role:
+
+- installs `epel-release` on RedHat-family systems when enabled
+- installs `fail2ban`
+- creates `/etc/fail2ban/jail.d/sshd.conf` from a template
+- enables and starts the `fail2ban` systemd service
+
+Example Playbook
+----------------
+
+See: `molecule/default/converge.yml`
+
+License
+-------
+
+MIT

roles/fail2ban_rhel/defaults/main.yml

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+---
+fail2ban_rhel_jail_sshd_enabled: true
+fail2ban_rhel_jail_sshd_port: ssh
+fail2ban_rhel_jail_sshd_findtime: 600
+fail2ban_rhel_jail_sshd_maxretry: 5
+fail2ban_rhel_jail_sshd_bantime: 3600
+fail2ban_rhel_jail_sshd_logpath: "%(sshd_log)s"
+fail2ban_rhel_jail_sshd_backend: "%(sshd_backend)s"
+fail2ban_rhel_jail_sshd_banaction: firewallcmd-multiport
+fail2ban_rhel_jail_sshd_ignoreips:
+  - 127.0.0.1/8
+  - ::1

roles/fail2ban_rhel/handlers/main.yml

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+---
+- name: Restart fail2ban
+  ansible.builtin.systemd:
+    name: fail2ban
+    state: restarted
+    enabled: true
+    daemon_reload: true

roles/fail2ban_rhel/meta/main.yml

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+---
+galaxy_info:
+  role_name: fail2ban_rhel
+  namespace: genlab
+  author: "Alexander Gorelyshev"
+  company: "Genlab, LLC"
+  description: "Deploy a lean Fail2Ban configuration for RHEL/Rocky 9+ hosts"
+  license: "MIT"
+  min_ansible_version: "2.1"
+
+  platforms:
+    - name: "EL"
+      versions: ["9"]
+    - name: "Rocky"
+      versions: ["9.2"]
+
+  galaxy_tags: []
+
+dependencies: []

roles/fail2ban_rhel/molecule/default/converge.yml

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+---
+- name: Converge
+  hosts: all
+  roles:
+    - role: genlab.common.fail2ban_rhel

roles/fail2ban_rhel/molecule/default/molecule.yml

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+---
+dependency:
+  name: galaxy
+
+driver:
+  name: docker
+
+platforms:
+  - name: rocky9
+    image: geerlingguy/docker-${MOLECULE_DISTRO:-rockylinux9}-ansible:latest
+    pre_build_image: true
+    command: ${MOLECULE_DOCKER_COMMAND:-""}
+    volumes:
+      - /sys/fs/cgroup:/sys/fs/cgroup:rw
+    cgroupns_mode: host
+    privileged: true
+
+provisioner:
+  name: ansible
+
+verifier:
+  name: ansible
+
+lint: |
+  set -e
+  yamllint .
+  ansible-lint .

roles/fail2ban_rhel/molecule/default/verify.yml

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+---
+- name: Verify
+  hosts: all
+  gather_facts: false
+  any_errors_fatal: true
+
+  tasks:
+    - name: "Check that the fail2ban service is active"
+      register: fail2ban_rhel_fail2ban_service
+      ansible.builtin.systemd:
+        name: fail2ban
+
+    - name: "Assert fail2ban is running"
+      ansible.builtin.assert:
+        that: fail2ban_rhel_fail2ban_service.status.ActiveState == "active"
+        success_msg: "fail2ban service is running"
+        fail_msg: "fail2ban service is not active"

roles/fail2ban_rhel/tasks/main.yml

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+---
+- name: "Install EPEL release on RedHat-family systems"
+  ansible.builtin.dnf:
+    name: "epel-release"
+    state: present
+
+- name: "Install fail2ban"
+  ansible.builtin.package:
+    name: "fail2ban"
+    state: present
+
+- name: "Ensure Fail2Ban jail configuration directory exists"
+  ansible.builtin.file:
+    path: /etc/fail2ban/jail.d
+    state: directory
+    owner: root
+    group: root
+    mode: "0755"
+
+- name: "Render sshd jail configuration"
+  notify: Restart fail2ban
+  ansible.builtin.template:
+    src: sshd.conf.j2
+    dest: /etc/fail2ban/jail.d/sshd.local
+    owner: root
+    group: root
+    mode: "0644"

roles/fail2ban_rhel/templates/sshd.conf.j2

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+[sshd]
+enabled = {{ fail2ban_rhel_jail_sshd.enabled | ternary('true', 'false') }}
+port = {{ fail2ban_rhel_jail_sshd.port }}
+
+logpath = {{ fail2ban_rhel_jail_sshd.logpath }}
+
+backend = {{ fail2ban_rhel_jail_sshd.backend }}
+banaction = {{ fail2ban_rhel_jail_sshd.banaction }}
+
+findtime = {{ fail2ban_rhel_jail_sshd.findtime }}
+maxretry = {{ fail2ban_rhel_jail_sshd.maxretry }}
+bantime = {{ fail2ban_rhel_jail_sshd.bantime }}
+
+ignoreip = {{ fail2ban_rhel.ignoreips | default([]) | join(' ') }}

roles/fail2ban_rhel/vars/main.yml

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+fail2ban_rhel_jail_sshd:
+  enabled: "{{ fail2ban_rhel_jail_sshd_enabled }}"
+  port: "{{ fail2ban_rhel_jail_sshd_port }}"
+  findtime: "{{ fail2ban_rhel_jail_sshd_findtime }}"
+  maxretry: "{{ fail2ban_rhel_jail_sshd_maxretry }}"
+  bantime: "{{ fail2ban_rhel_jail_sshd_bantime }}"
+  logpath: "{{ fail2ban_rhel_jail_sshd_logpath }}"
+  backend: "{{ fail2ban_rhel_jail_sshd_backend }}"
+  banaction: "{{ fail2ban_rhel_jail_sshd_banaction }}"
+  ignoreips: "{{ fail2ban_rhel_jail_sshd_ignoreips }}"