gpg-lacre/INSTALL.md

Installation instructions

Content

• General information
• Install Lacre
• Install Lacre-Webgate
• Install Register-handler

General information

Lacre is divided in 3 main parts: Lacre itself, Lacre-Webgate and Register-handler. Some parts of the Lacre project depend on other parts of the project. You will find information about these dependencies at the beginning of every installation part.

These instructions show you how to set up Lacre in an easy way. If you are a more advanced user, feel free to experiment with the settings. For these instructions a home directory for the user nobody is set. Sadly this is an odd workaround but no better solution was found.

These instructions are based on an installation on an Ubuntu 14.04 LTS virtual machine. For other Linux distributions and other versions these instructions might need to be adapted to your distribution (e.g. installation of packages and used directories).

Install Lacre

Requirements

• Python 3.9.
• Dependencies listed in requirements file, requirements.txt.
• Postfix: installed, configured and tested.
• GnuPG: installed, configured and tested (e.g. via command-line).

Installation

1. Install the dependencies:

python -m pip install -r requirements.txt

2. Set the home directory for the user nobody (sadly this workaround is needed as there is no better solution at this point). If you get an error that the user is currently used by a process, you might need to kill the process manually.

usermod -d /var/gpgmailgate nobody

3. Create dedicated directories for storing PGP keys and S/MIME certificates and make the user nobody owner of these:

install -u nobody -g nobody -d /var/gpgmailgate/ /var/gpgmailgate/.gnupg /var/gpgmailgate/smime

4. Place the lacre.py in /usr/local/bin/, make the user nobody owner of the file and make it executable:

install -u nobody -g nobody -mode u=rx lacre.py /usr/local/bin/

5. Place GnuPG and lacre directories in /usr/local/lib/python3.x/dist-packages (replace 3.x with your Python version). Make sure they're available for Python imports by executing python -m lacre.admin -h command.

6. Configure /etc/lacre.conf based on the provided lacre.conf.sample. Change the settings according to your configuration. If you follow this guide and have a standard configuration for postfix, you don't need to change much.

7. Configure logging by copying lacre-logging.conf.sample to /etc/lacre-logging.conf and editing it according to your needs. The path to this file is included in [logging] section of lacre.conf file, so if you place it somewhere else, make sure to update the path too. See also: Python logging package's Configuration file format.

8. Add the following to the end of /etc/postfix/master.cf

lacre    unix    -   n   n   -   -   pipe
    flags= user=nobody argv=/usr/local/bin/lacre.py ${recipient}

127. 0. 0. 1:10028 inet    n   -   n   -   10  smtpd
    -o content_filter=
    -o receive_override_options=no_unknown_recipient_checks,no_header_body_checks
    -o smtpd_helo_restrictions=
    -o smtpd_client_restrictions=
    -o smtpd_sender_restrictions=
    -o smtpd_recipient_restrictions=permit_mynetworks,reject
    -o mynetworks=127. 0. 0. 0/8
    -o smtpd_authorized_xforward_hosts=127. 0. 0. 0/8

If you use Postfix versions from 2.5 onwards, it is recommended to change ${recipient} to ${original_recipient} in second line of the snippet above.

9. Add the following line to /etc/postfix/main.cf

content_filter = lacre

10. Optional: GPG can automatically download new public keys for automatic signature verification. To enable automatic create the file /var/gpgmailgate/.gnupg/gpg.conf. Add the following line to the file:

keyserver-options auto-key-retrieve

11. Restart Postfix

You are now ready to go. To add a public key for encryption just use the following command:

sudo -u nobody /usr/bin/gpg --homedir=/var/gpgmailgate/.gnupg --import /some/public.key

• Replace /some/public.key with the location of a public key (/some/public.key can be deleted after the import).
• Confirm that it's working: sudo -u nobody /usr/bin/gpg --list-keys --homedir=/var/gpgmailgate/.gnupg

If you already have a keyring you would like to import into Lacre, you can use lacre.admin command-line utility. Read more in Lacre administration.

Please also test your installation before using it.

Lacre is also able to handle S/MIME certificates for encrypting mails. However, it is best to use it in combination with Register-Handler described later to add new certificates. If you try to add them manually it might fail. The certificates are stored in /var/gpgmailgate/smime in PKCS7 format and are named like User@example.com (the user part is case sensitive, the domain part should be in lower case).

Additional settings

Most mail servers do not handle mail addresses case sensitive. If you know that all your recipient mail servers do not care about case sensitivity then you can set mail_case_insensitive in the settings to yes so looking up PGP keys or S/MIME certificates does also happen case insensitive. If your recipients have problems to decrypt mails encrypted by Lacre they might use a piece of software that does not support PGP/MIME encrypted mails. You can tell Lacre to use the legacy PGP/INLINE format by adding the recipient to the pgp_style map in the following format: User@example.com=inline

Install Lacre-Webgate

Requirements

• A webserver is installed and reachable
• The webserver is able to handle PHP scripts
• MySQL is installed
• Python 3.x is already installed

Installation

All files you need can be found in the Lacre / lacre-webgate repository.

1. Install the Python-mysqldb and Python-markdown modules:

apt-get install python-mysqldb python-markdown

2. Create a new database for Lacre-Webgate.

3. Import the schema file schema.sql into the newly created database.

4. Edit the config file located at /etc/lacre.conf. Set enabled = yes in [database] and fill in the necessary settings for the database connection.

5. Copy the files located in the public_html directory onto your webserver. They can also be placed in a subdirectory on your webserver.

6. On your webserver move the config.sample.php file to config.php and edit the configuration file.

7. Create directories for storing email templates:

mkdir -p /var/gpgmailgate/cron_templates

8. Copy the templates found in the cron_templates directory into the newly created directory and transfer ownership:

chown -R nobody:nogroup /var/gpgmailgate/cron_templates

9. Copy cron.py to /usr/local/bin/cron.py. Make it executable and and transfer ownership to nobody:

install -u nobody -g nobody -m u+x cron.py /usr/local/bin/lacre-cron.py

10. Create /etc/cron.d/lacre-cron with contents: */3 * * * * nobody /usr/bin/python /usr/local/bin/lacre-cron.py > /dev/null for executing the cron job automatically.

11. Test your installation.

Lacre-Webgate as keyserver

Lacre-Webgate can also be used as a keyserver. For more information have a look at Lacre-Webgate's README.

Install Register-handler

Requirements

• Already set up and working Lacre-Webgate. It should be reachable from the machine that will run register-handler
• Postfix is already installed and configured. It is recommended that you have already tested your configuration so we can exclude this as a main cause of problems. Your Postfix configuration should also support aliases

Installation

1. Install the Python-requests module:

apt-get install python-requests

2. Create directories for storing email templates:

mkdir -p /var/gpgmailgate/register_templates

3. Copy the templates found in the register_templates directory into the newly created directory and transfer ownership:

chown -R nobody:nogroup /var/gpgmailgate/register_templates

4. Copy register-handler.py to /usr/local/bin/register-handler.py. Make it executable and own it to nobody:

install -u nobody -g nogroup -m a+x register-handler.py /usr/local/bin/

5. Edit the config file located at /etc/lacre.conf. Set the parameter webpanel_url in [mailregister] to the url of your Lacre-Webgate panel (the URL should be the same as the one you use to access the panel with your web browser). Also set the parameter register_email to the email address you want the user to see when receiving mails from the register-handler (it does not have to be an existing address but it is recommended). Register-handler will send users mails when they are registering S/MIME certificates or when neither a S/MIME certificate nor a PGP key was found in a mail sent to the register-handler.

6. Add register: |/usr/local/bin/register-handler.py to /etc/aliases

7. Update postfix's alias database with postalias /etc/aliases

8. Restart postfix.

9. Test your installation.