majic-ansible-roles Changeset

Changeset - 441a70c073b9

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Branko Majic (branko) - 13 months ago 2024-03-07 22:41:28
branko@majic.rs

MAR-232: Switch to using IP addreses in firewall rules for mail_forwarder role:

- Perform lookups on managed machine for the passed-in SMTP relay
host, and use those values when populating the firewall rules.

9 files changed with 77 insertions and 24 deletions:

docs/about.rst

docs/index.rst

docs/releasenotes.rst

docs/rolereference.rst

docs/usage.rst

requirements.in

requirements.txt

roles/mail_forwarder/tasks/main.yml

roles/mail_forwarder/templates/ferm_mail.conf.j2

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docs/about.rst

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@@ @@ -17,10 +17,9 @@ supported releases, see :ref:`rolereference`. @@
 At the moment, the roles have been written for and tested against **Ansible
 .9.x**.
 The roles also utilise the ``dig`` and ``ipv4/ipv6`` lookup plugins
 which require ``dnspython`` and ``netaddr`` packages (respectively) to
 be installed. Make sure you have the packages available on controller
 machine.
 The roles also utilise the ``ipv4/ipv6`` lookup plugins which require
 ``netaddr`` package to be installed. Make sure you have the packages
 available on controller machine.
 Why were these roles created?

docs/index.rst

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@@ @@ -17,10 +17,9 @@ supported releases, see :ref:`rolereference`. @@
 At the moment, the roles have been written for and tested against **Ansible
 .9.x**.
 The roles also utilise the ``dig`` and ``ipv4/ipv6`` lookup plugins
 which require ``dnspython`` and ``netaddr`` packages (respectively) to
 be installed. Make sure you have the packages available on controller
 machine.
 The roles also utilise the ``ipv4/ipv6`` lookup plugins which require
 ``netaddr`` package to be installed. Make sure you have the packages
 available on controller machine.
 Contents

docs/releasenotes.rst

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@@ @@ -15,6 +15,8 @@ Debian 12 Bookworm. Some minor improvements and fixes. @@
   * Dropped support for Debian 10 (Buster).
   * Added support for Debian 12 (Bookworm).
   * ``netaddr`` Python package is now required for using the roles.
   * ``dnspython`` Python package is no longer required for using the
     roles.
 * ``backup_client`` role
@@ @@ -43,9 +45,7 @@ Debian 12 Bookworm. Some minor improvements and fixes. @@
   * Parameter ``maintenance_allowed_hosts`` has been dropped and
     replaced with parameter ``maintenance_allowed_sources``. The new
     parameter expects a list of IPv4 and IPv6 addresses (or
     subnets). Resolvable names can no longer be specified (and this
     particular role no longe relies on presence of the ``dnspython``
     package).
     subnets). Resolvable names can no longer be specified.
   * NTP server configuration is now based on use of pools instead of
     servers. Parameter ``ntp_servers`` has been deprecated and
@@ @@ -61,6 +61,20 @@ Debian 12 Bookworm. Some minor improvements and fixes. @@
     LDAP server logs can be read via ``journalctl -u slapd`` when
     necessary.
 * ``mail_forwarder`` role
   * Firewall rules for incoming connections from the SMTP relay server
     are now based on relay's IPv4 and IPv6 addresses as resolved on
     managed machine during deployment time.
     In case the SMTP relay server's IP addresses change, the role
     needs to get reapplied against managed machines for those changes
     to take place.
     This change in behaviour was introduced to avoid firewall-related
     errors due to inability to resolve names via DNS servers during
     boot time.
 * ``mail_server`` role
   * Parameter ``mail_server_tls_protocols`` has been dropped and

docs/rolereference.rst

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@@ @@ -1315,8 +1315,15 @@ The role implements the following: @@
 * Purges Exim4 configuration (just in case).
 * Sets-up aliases for the local recipients.
 * Installs SWAKS (utility for testing SMTP servers).
 * Configures firewall to accept SMTP connections from SMTP relay (if one has
   been configured). This allows for delivery of bounced e-mails.
 * Configures firewall to accept SMTP connections from SMTP relay (if
   one has been configured). This allows for delivery of bounced
   e-mails.
   .. note::
      Firewall rules are based on IPv4 and IPv6 addresses resolved via
      managed server at time of deployment. If the SMTP relay changes
      its IP addresess, this role needs to be reapplied against the
      managed machines.
 Postfix is configured as follows:

docs/usage.rst

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      mkdir ~/mysite/
      mkvirtualenv -p /usr/bin/python3 -a ~/mysite/ mysite
      pip install -U pip setuptools
-     pip install 'ansible~=2.9.0' dnspython netaddr
      pip install 'ansible~=2.9.0' netaddr
 .. warning::
    The ``dnspython`` and ``netaddr`` packages are needed since they
    are used internally by some of the roles for the ``dig`` and
    ``ipv4/ipv6`` lookup plugins.
    The ``netaddr`` package is needed for ``ipv4/ipv6`` lookup plugins
    which is used internally by some of the roles.
 Cloning the *Majic Ansible Roles*

requirements.in

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 ansible~=2.9.0
 defusedxml
 dnspython
 gimmecert~=0.5.0
 molecule~=2.22.0
 netaddr

requirements.txt

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@@ @@ -68,8 +68,6 @@ defusedxml==0.7.1 @@
     # via -r requirements.in
 distlib==0.3.8
     # via virtualenv
 dnspython==2.6.1
     # via -r requirements.in
 docutils==0.20.1
     # via
     #   sphinx
@@ @@ -126,7 +124,7 @@ pathspec==0.12.1 @@
     # via yamllint
 pexpect==4.9.0
     # via molecule
-pip-tools==7.4.0
+pip-tools==7.4.1
     # via -r requirements.in
 platformdirs==4.2.0
     # via virtualenv

roles/mail_forwarder/tasks/main.yml

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@@ @@ -70,6 +70,38 @@ @@
     state: started
     enabled: true
 - name: Retrieve IPv4 addresses of SMTP relay host
   shell: "getent ahostsv4 '{{ smtp_relay_host }}' | awk '{ print $1 }' | sort -u"  # noqa 306
   # [306] Shells that use pipes should set the pipefail option
   #   The getent ahostsv4 command has non-zero exit code if the
   #   supplies name cannot be resolved. However, that is a valid
   #   use-case for extracting this information. It effectively means
   #   that no IPv4 firewall rules will be deployed for allowing
   #   incoming connections from the SMTP relay host.
   changed_when: false
   register: smtp_relay_host_ipv4
 - name: Retrieve IPv6 addresses of SMTP relay host
   shell: "getent ahostsv6 '{{ smtp_relay_host }}' | awk '{ print $1 }' | grep -v '^::ffff:' | sort -u"  # noqa 306
   # [306] Shells that use pipes should set the pipefail option
   #   The getent ahostsv6 command has non-zero exit code if the
   #   supplies name cannot be resolved. However, that is a valid
   #   use-case for extracting this information. It effectively means
   #   that no IPv6 firewall rules will be deployed for allowing
   #   incoming connections from the SMTP relay host.
   changed_when: false
   register: smtp_relay_host_ipv6
 - name: Normalise the SMTP relay host IPv4 addresses variable
   set_fact:
     smtp_relay_host_ipv4: "{{ smtp_relay_host_ipv4.stdout_lines | reject('equalto', '') | list }}"
   when: "smtp_relay_host | length != 0"
 - name: Normalise the SMTP relay host IPv6 addresses variable
   set_fact:
     smtp_relay_host_ipv6: "{{ smtp_relay_host_ipv6.stdout_lines | reject('equalto', '') | list }}"
   when: "smtp_relay_host | length != 0"
 - name: Deploy firewall configuration for mail forwader
   template:
     src: "ferm_mail.conf.j2"

roles/mail_forwarder/templates/ferm_mail.conf.j2

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 {% if smtp_relay_host and smtp_from_relay_allowed %}
 {% if smtp_relay_host_ipv4 %}
 domain ip {
     # Accept incoming connections on port 25 from SMTP relay host.
     table filter {
         chain INPUT {
             # SMTP for server communication.
             proto tcp dport 25 {
                 saddr {{ smtp_relay_host }} ACCEPT;
 {% for address in smtp_relay_host_ipv4 %}
                 saddr {{ address }} ACCEPT;
 {% endfor %}
+            }
+        }
+    }
+}
 {% endif %}
-{% if lookup('dig', smtp_relay_host + '/AAAA') not in ['NXDOMAIN', ''] %}
+{% if smtp_relay_host_ipv6 %}
 domain ip6 {
     # Accept incoming connections on port 25 from SMTP relay host.
     table filter {
         chain INPUT {
             # SMTP for server communication.
             proto tcp dport 25 {
                 saddr {{ smtp_relay_host }} ACCEPT;
 {% for address in smtp_relay_host_ipv6 %}
                 saddr {{ address }} ACCEPT;
 {% endfor %}
+            }
+        }
+    }

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