Programming

Apache: enable HTTPS

To enable HTTP Secure (HTTPS) on Apache, we first enable the modules called mod_ssl and mod_socache_shmcb in the main Apache configuration file, located at /etc/httpd/conf/httpd.conf:

LoadModule socache_shmcb_module modules/mod_socache_shmcb.so
LoadModule ssl_module modules/mod_ssl.so

We include SSL own configuration file:

# Secure (SSL/TLS) connections
Include conf/extra/httpd-ssl.conf

In this file, we also set a document root (or keep the default path depending on where we put our web application) and a server name. We use the default 443 port.

DocumentRoot "/srv/http/secure_application"
ServerName localhost:443

We can also edit the path to our certificate files but I kept mines at the default location:

SSLCertificateFile "/etc/httpd/conf/server.crt"
[...]
SSLCertificateKeyFile "/etc/httpd/conf/server.key"

Finally we need to get or generate our certificate. I have created a self-signed one for my development environment but it is not recommended on live servers. As written above, I kept the default path so in this example we are going to create our certificate in that folder. We start by generating our key:

$ cd /etc/httpd/conf/
$ sudo openssl genrsa -out server.key 4096
Generating RSA private key, 4096 bit long modulus [...]

This is our private key so we need to restrict permissions to make sure no one else can read it:

$ sudo chmod 600 server.key

Then we need to generate the Certificate Signing Requests (CSR). We are prompted for a few informations which can be left blank but the important one is Common Name, which must be the domain of our site like www.drkdidel.be or *.drkdidel.be. But for our development environment, we just write localhost.

$ sudo openssl req -new -key server.key -out server.csr
You are about to be asked to enter information that will be incorporated into your certificate request.
[...]
Common Name (e.g. server FQDN or YOUR name) []:localhost

Finally we generate our certificate and restart Apache:

$ sudo openssl x509 -req -days 3650 -in server.csr -signkey server.key -out server.crt
$ sudo systemctl restart httpd.service

Now we can browse to https://localhost/ and make the browser display a worrying alert:

Warning message displayed by Firefox

This is caused by our self-signed certificate which has no security value (if you see this on a live website, you should follow the advice of "Getting out of here!"). In Firefox, we can click on "I Understand the Risks" then on the "Add Exception..." button. This will display a pop-up window where we can tell Firefox to not bother us again when accessing our server. Check "Permanently store this exception" then click "Confirm Security Exception" which will close the pop-up and reload the page:

Pop-up window "Add Security Exception"

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