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MySQL SSL Support: Why do I need it?

In a typical Silverstripe set up, you will only need to use a single host to function as the web server, email server, database server, among others.

In some cases, however, you may be required to connect to a database on a remote host. Connecting to a remote host without SSL encryption exposes your data to packet sniffing and may compromise the security of your Silverstripe instance.

This article demonstrates how to generate SSL certificates using MySQL and implementing them in Silverstripe.

This article assumes that you have MySQL and OpenSSL installed.

Generating Certificates

There are three components to an SSL certificate implementation. The first two components are the private key, and the public certificate, which are mathematically-generated, symetrical pieces of the puzzle that allow public-key cryptography to work. The third component is the Certificate Authority (CA) certificate that signs the pubic key to prove its validity.

In the case of MySQL, we will need to generate three sets of certificates, namely:

  • the CA key and certificate
  • the server key and certificate
  • the client key and certificate

We also need to sign the certificates with our generated CA.

The commands below illustrate how to do so on your MySQL host.

The following commands will work on Linux/Unix based servers. For other servers such as windows, refer to the MySQL documentation


# Create directory
sudo mkdir ssl
cd ssl

# Generate CA key and CA cert
sudo openssl genrsa 2048 | sudo tee -a ca-key.pem
sudo openssl req -new -x509 -nodes -days 365000 -key ca-key.pem -out ca-cert.pem

# Generate SERVER key and server certificate signing request
# IMPORTANT: the common name of the certificate should match the domain name of your host!
sudo openssl rsa -in server-key.pem -out server-key.pem
sudo openssl req -newkey rsa:2048 -days 365000 -nodes -keyout server-key.pem -out server-req.pem

# Generate and sign SERVER certificate
sudo openssl x509 -req -in server-req.pem -days 365000 -CA ca-cert.pem -CAkey ca-key.pem -set_serial 01 -out server-cert.pem

# Generate CLIENT key and certificate signing request
sudo openssl rsa -in client-key.pem -out client-key.pem
sudo openssl req -newkey rsa:2048 -days 365000 -nodes -keyout client-key.pem -out client-req.pem

# Generate and sign CLIENT certificate
sudo openssl x509 -req -in client-req.pem -days 365000 -CA ca-cert.pem -CAkey ca-key.pem -set_serial 01 -out client-cert.pem

# Verify validity of generated certificates
sudo openssl verify -CAfile ca-cert.pem server-cert.pem client-cert.pem

After generating the certificates, make sure to set the correct permissions to prevent unauthorized access to your keys!

It is critical that the key files (files ending in *key.pem) are kept secret. Once these files are exposed, you will need to regenerate the certificates to prevent exposing your data traffic.

# Set permissions readonly permissions and change owner to root
sudo chown root:root *.pem 
sudo chmod 440 *.pem

# Server certificates need to be readable by mysql
sudo chgrp mysql server*.pem
sudo mv *.pem /etc/mysql/ssl

Setting up MySQL to use SSL certificates

For Debian/Ubuntu instances, the configuration file is usually in /etc/mysql/my.cnf. Refer to your MySQL manual for more information

We must edit the MySQL configuration to use the newly generated certificates.

Edit your MySQL configuration file as follows.

[mysqld]
...
ssl-ca=/etc/mysql/ca-cert.pem
ssl-cert=/etc/mysql/server-cert.pem
ssl-key=/etc/mysql/server-key.pem

# IMPORTANT! When enabling MySQL remote connections, make sure to take adequate steps to secure your machine from unathorized access!
bind-address=0.0.0.0

Enabling remote connections to your MySQL instance introduces various security risks. Make sure to take appropriate steps to secure your instance by using a strong password, disabling MySQL root access, and using a firewall to only accept qualified hosts, for example.

Make sure to restart your MySQL instance to reflect the changes.

sudo service mysql restart

Setting up Silverstripe to connect to MySQL

Now that we have successfully setup the SSL your MySQL host, we now need to configure Silverstripe to use the certificates.

Copying SSL Certificates

First we need to copy the client certificate files to the Silverstripe instance. You will need to copy:

  • client-key.pem
  • client-cert.pem
  • ca-cert.pem

Make sure to only copy client-key.pem, client-cert.pem, and ca-cert.pem to avoid leaking your credentials!

On your Silverstripe instance:

# Secure copy over SSH via rsync command. You may use an alternative method if desired. 
rsync -avP [email protected]:/path/to/client/certs /path/to/secure/folder

#  Depending on your web server configuration, allow web server to read to SSL files
sudo chown -R www-data:www-data /path/to/secure/folder
sudo chmod 750 /path/to/secure/folder
sudo chmod 400 /path/to/secure/folder/*

Setting up _ss_environment.php to use SSL certificates

SS_DATABASE_SERVER does not accept IP-based hostnames. Also, if the domain name of the host does not match the common name you used to generate the server certificate, you will get anSSL certificate mismatch error`.

Add or edit your _ss_environment.php configuration file. (See Environment Management for more information.)

<?php

// These four define set the database connection details.
define('SS_DATABASE_CLASS', 'MySQLDatabase');

define('SS_DATABASE_SERVER', 'db1.example.com');
define('SS_DATABASE_USERNAME', 'dbuser');
define('SS_DATABASE_PASSWORD', '<password>');

// These define the paths to the SSL key, certificate, and CA certificate bundle.
define('SS_DATABASE_SSL_KEY', '/home/newdrafts/mysqlssltest/client-key.pem');
define('SS_DATABASE_SSL_CERT', '/home/newdrafts/mysqlssltest/client-cert.pem');
define('SS_DATABASE_SSL_CA', '/home/newdrafts/mysqlssltest/ca-  cert.pem');

// When using SSL connections, you also need to supply a username and password to override the default settings
define('SS_DEFAULT_ADMIN_USERNAME', 'username');
define('SS_DEFAULT_ADMIN_PASSWORD', 'password');

When running the installer, make sure to check on the Use _ss_environment file for configuration option under the Database Configuration section to use the environment file.

Conclusion

That's it! We hope that this article was able to help you configure your remote MySQL SSL secure database connection.

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