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DevTut

SSL Connection Setup

Setup for Debian-based systems

Section titled “Setup for Debian-based systems”

(This assumes MySQL has been installed and that sudo is being used.)

Generating a CA and SSL keys

Section titled “Generating a CA and SSL keys”

Make sure OpenSSL and libraries are installed:

apt-get -y install openssl
apt-get -y install libssl-dev

Next make and enter a directory for the SSL files:

mkdir /home/ubuntu/mysqlcerts
cd /home/ubuntu/mysqlcerts

To generate keys, create a certificate authority (CA) to sign the keys (self-signed):

openssl genrsa 2048 > ca-key.pem
openssl req -new -x509 -nodes -days 3600 -key ca-key.pem -out ca.pem

The values entered at each prompt won’t affect the configuration. Next create a key for the server, and sign using the CA from before:

openssl req -newkey rsa:2048 -days 3600 -nodes -keyout server-key.pem -out server-req.pem
openssl rsa -in server-key.pem -out server-key.pem


openssl x509 -req -in server-req.pem -days 3600 -CA ca.pem -CAkey ca-key.pem -set_serial 01 -out server-cert.pem

Then create a key for a client:

openssl req -newkey rsa:2048 -days 3600 -nodes -keyout client-key.pem -out client-req.pem
openssl rsa -in client-key.pem -out client-key.pem
openssl x509 -req -in client-req.pem -days 3600 -CA ca.pem -CAkey ca-key.pem -set_serial 01 -out client-cert.pem

To make sure everything was set up correctly, verify the keys:

openssl verify -CAfile ca.pem server-cert.pem client-cert.pem

Adding the keys to MySQL

Section titled “Adding the keys to MySQL”

Open the MySQL configuration file. For example:

vim /etc/mysql/mysql.conf.d/mysqld.cnf

Under the [mysqld] section, add the following options:

ssl-ca = /home/ubuntu/mysqlcerts/ca.pem
ssl-cert = /home/ubuntu/mysqlcerts/server-cert.pem
ssl-key = /home/ubuntu/mysqlcerts/server-key.pem

Restart MySQL. For example:

service mysql restart

Test the SSL connection

Section titled “Test the SSL connection”

Connect in the same way, passing in the extra options ssl-ca, ssl-cert, and ssl-key, using the generated client key. For example, assuming cd /home/ubuntu/mysqlcerts:

mysql --ssl-ca=ca.pem --ssl-cert=client-cert.pem --ssl-key=client-key.pem -h 127.0.0.1 -u superman -p

After logging in, verify the connection is indeed secure:

superman@127.0.0.1 [None]> SHOW VARIABLES LIKE '%ssl%';
+---------------+-----------------------------------------+
| Variable_name | Value                                   |
+---------------+-----------------------------------------+
| have_openssl  | YES                                     |
| have_ssl      | YES                                     |
| ssl_ca        | /home/ubuntu/mysqlcerts/ca.pem          |
| ssl_capath    |                                         |
| ssl_cert      | /home/ubuntu/mysqlcerts/server-cert.pem |
| ssl_cipher    |                                         |
| ssl_crl       |                                         |
| ssl_crlpath   |                                         |
| ssl_key       | /home/ubuntu/mysqlcerts/server-key.pem  |
+---------------+-----------------------------------------+

You could also check:

superman@127.0.0.1 [None]> STATUS;
...
SSL:                    Cipher in use is DHE-RSA-AES256-SHA
...

Enforcing SSL

Section titled “Enforcing SSL”

This is via GRANT, using REQUIRE SSL:

GRANT ALL PRIVILEGES ON *.* TO 'superman'@'127.0.0.1' IDENTIFIED BY 'pass' REQUIRE SSL;
FLUSH PRIVILEGES;

Now, superman must connect via SSL.

If you don’t want to manage client keys, use the client key from earlier and automatically use that for all clients. Open MySQL configuration file, for example:

vim /etc/mysql/mysql.conf.d/mysqld.cnf

Under the [client] section, add the following options:

ssl-ca = /home/ubuntu/mysqlcerts/ca.pem
ssl-cert = /home/ubuntu/mysqlcerts/client-cert.pem
ssl-key = /home/ubuntu/mysqlcerts/client-key.pem

Now superman only has to type the following to login via SSL:

mysql -h 127.0.0.1 -u superman -p

Connecting from another program, for example in Python, typically only requires an additional parameter to the connect function. A Python example:

import MySQLdb
ssl = {'cert': '/home/ubuntu/mysqlcerts/client-cert.pem', 'key': '/home/ubuntu/mysqlcerts/client-key.pem'}
conn = MySQLdb.connect(host='127.0.0.1', user='superman', passwd='imsoawesome', ssl=ssl)

References and further reading:

Section titled “References and further reading:”

Setup for CentOS7 / RHEL7

Section titled “Setup for CentOS7 / RHEL7”

This example assumes two servers:

  1. dbserver (where our database lives)
  2. appclient (where our applications live)

FWIW, both servers are SELinux enforcing.

First, log on to dbserver

Section titled “First, log on to dbserver”

Create a temporary directory for creating the certificates.

mkdir /root/certs/mysql/ && cd /root/certs/mysql/

Create the server certificates

openssl genrsa 2048 > ca-key.pem
openssl req -sha1 -new -x509 -nodes -days 3650 -key ca-key.pem > ca-cert.pem
openssl req -sha1 -newkey rsa:2048 -days 730 -nodes -keyout server-key.pem > server-req.pem
openssl rsa -in server-key.pem -out server-key.pem
openssl x509 -sha1 -req -in server-req.pem -days 730  -CA ca-cert.pem -CAkey ca-key.pem -set_serial 01 > server-cert.pem

Move server certificates to /etc/pki/tls/certs/mysql/

Directory path assumes CentOS or RHEL (adjust as needed for other distros):

mkdir /etc/pki/tls/certs/mysql/

Be sure to set permissions on the folder and files. mysql needs full ownership and access.

chown -R mysql:mysql /etc/pki/tls/certs/mysql

Now configure MySQL/MariaDB

# vi /etc/my.cnf
# i
[mysqld]
bind-address=*
ssl-ca=/etc/pki/tls/certs/ca-cert.pem
ssl-cert=/etc/pki/tls/certs/server-cert.pem
ssl-key=/etc/pki/tls/certs/server-key.pem
# :wq

Then

systemctl restart mariadb

Don’t forget to open your firewall to allow connections from appclient (using IP 1.2.3.4)

firewall-cmd --zone=drop --permanent --add-rich-rule 'rule family="ipv4" source address="1.2.3.4" service name="mysql" accept'
# I force everything to the drop zone.  Season the above command to taste.

Now restart firewalld

service firewalld restart

Next, log in to dbserver’s mysql server:

mysql -uroot -p

Issue the following to create a user for the client. note REQUIRE SSL in GRANT statement.

GRANT ALL PRIVILEGES ON *.* TO ‘iamsecure’@’appclient’ IDENTIFIED BY ‘dingdingding’ REQUIRE SSL;
FLUSH PRIVILEGES;
# quit mysql

You should still be in /root/certs/mysql from the first step. If not, cd back to it for one of the commands below.

Create the client certificates

openssl req -sha1 -newkey rsa:2048 -days 730 -nodes -keyout client-key.pem > client-req.pem
openssl rsa -in client-key.pem -out client-key.pem
openssl x509 -sha1 -req -in client-req.pem -days 730 -CA ca-cert.pem -CAkey ca-key.pem -set_serial 01 > client-cert.pem

Note: I used the same common name for both server and client certificates. YMMV.

Be sure you’re still /root/certs/mysql/ for this next command

Combine server and client CA certificate into a single file:

cat server-cert.pem client-cert.pem > ca.pem

Make sure you see two certificates:

cat ca.pem

END OF SERVER SIDE WORK FOR NOW.

Section titled “END OF SERVER SIDE WORK FOR NOW.”

Open another terminal and

ssh appclient

As before, create a permanent home for the client certificates

mkdir /etc/pki/tls/certs/mysql/

Now, place the client certificates (created on dbserver) on appclient. You can either scp them over, or just copy and paste the files one by one.

scp dbserver
# copy files from dbserver to appclient
# exit scp

Again, be sure to set permissions on the folder and files. mysql needs full ownership and access.

chown -R mysql:mysql /etc/pki/tls/certs/mysql

You should have three files, each owned by user mysql:

/etc/pki/tls/certs/mysql/ca.pem
/etc/pki/tls/certs/mysql/client-cert.pem
/etc/pki/tls/certs/mysql/client-key.pem

Now edit appclient’s MariaDB/MySQL config in the [client] section.

vi /etc/my.cnf
# i
[client]
ssl-ca=/etc/pki/tls/certs/mysql/ca.pem
ssl-cert=/etc/pki/tls/certs/mysql/client-cert.pem
ssl-key=/etc/pki/tls/certs/mysql/client-key.pem
# :wq

Restart appclient’s mariadb service:

systemctl restart mariadb

still on the client here

Section titled “still on the client here”

This should return: ssl TRUE

mysql --ssl --help

Now, log in to appclient’s mysql instance

mysql -uroot -p

Should see YES to both variables below

show variables LIKE '%ssl';
    have_openssl    YES
    have_ssl              YES

Initially I saw

have_openssl NO

A quick look into mariadb.log revealed:

SSL error: Unable to get certificate from '/etc/pki/tls/certs/mysql/client-cert.pem'

The problem was that root owned client-cert.pem and the containing folder. The solution was to set ownership of /etc/pki/tls/certs/mysql/ to mysql.

chown -R mysql:mysql /etc/pki/tls/certs/mysql

Restart mariadb if needed from the step immediately above

NOW WE ARE READY TO TEST THE SECURE CONNECTION

Section titled “NOW WE ARE READY TO TEST THE SECURE CONNECTION”

We’re still on appclient here

Section titled “We’re still on appclient here”

Attempt to connect to dbserver’s mysql instance using the account created above.

mysql -h dbserver -u iamsecure -p
# enter password dingdingding (hopefully you changed that to something else)

With a little luck you should be logged in without error.

To confirm you are connected with SSL enabled, issue the following command from the MariaDB/MySQL prompt:

\s

That’s a backslash s, aka status

That will show the status of your connection, which should look something like this:

Connection id:        4
Current database:
Current user:        iamsecure@appclient
SSL:            Cipher in use is DHE-RSA-AES256-GCM-SHA384
Current pager:        stdout
Using outfile:        ''
Using delimiter:    ;
Server:            MariaDB
Server version:        5.X.X-MariaDB MariaDB Server
Protocol version:    10
Connection:        dbserver via TCP/IP
Server characterset:    latin1
Db     characterset:    latin1
Client characterset:    utf8
Conn.  characterset:    utf8
TCP port:        3306
Uptime:            42 min 13 sec

If you get permission denied errors on your connection attempt, check your GRANT statement above to make sure there aren’t any stray characters or ’ marks.

If you have SSL errors, go back through this guide to make sure the steps are orderly.

This worked on RHEL7 and will likely work on CentOS7, too. Cannot confirm whether these exact steps will work elsewhere.

Hope this saves someone else a little time and aggravation.