create self signed multi domain certificate

I have a domain mydomain.com with some sub level domains like

• nexus.mydomain.com
• svn.mydomain.com
• http://www.mydomain.com

Now I need a self signed certificate for all these domains because I want to use them over HTTPS. There are some steps to do this. First of all: you don’t need for this propose your own root certificate. You should replace all occurence of mydomain.com with your own domain name and sub domains.

On the gentoo server where the apache should host the domains, I have to create the certificate. I do following steps:

1. Generate a private key

   openssl genrsa -des3 -out server.key 1024
   

2. Generate a CSR (Certificate Signing Request)

   openssl req -new -key mydomain.key -out mydomain.csr
   
   Country Name (2 letter code) [DE]:DE
   State or Province Name (full name) [Sachsen]:Sachsen
   Locality Name (eg, city) [Leipzig]:Leipzig
   Organization Name (eg, company) [My Company Ltd]:mydomain.com
   Organizational Unit Name (eg, section) []:Information Technology
   Common Name (eg, your name or your server's hostname) []:mydomain.com
   Email Address []:thomas dot wabner at mydomain dot com
   Please enter the following 'extra' attributes
   to be sent with your certificate request
   A challenge password []:
   An optional company name []:
   

3. Remove Passphrase from Key

   cp mydomain.key mydomain.key.org
   openssl rsa -in mydomain.key.org -out mydomain.key
   

4. Generating a Self-Signed Certificate

   To include all required subdomains a extensions file must be used. For example I have created a file /home/waffel/ssl/mydomain_extensions with following content:

   [ mydomain_http ]
   nsCertType      = server
   keyUsage        = digitalSignature,nonRepudiation,keyEncipherment
   extendedKeyUsage        = serverAuth
   subjectKeyIdentifier    = hash
   authorityKeyIdentifier  = keyid,issuer
   subjectAltName          = @mydomain_http_subject
   [ mydomain_http_subject ]
   DNS.1 = www.mydomain.com
   DNS.2 = nexus.mydomain.com
   DNS.3 = trac.mydomain.com
   DNS.4 = svn.mydomain.com
   

   The last command to create the certificate is:

   openssl x509 -req -days 365 -in mydomain.csr -signkey mydomain.key -out mydomain.crt -extfile /home/waffel/ssl/mydomain_extensions -extensions mydomain_http
   

In the apache configuration for the ssl host’s I have enabled the ssl module with following content:

...
ServerAlias svn.mydomain.com trac.mydomain.com nexus.mydomain.com

        ErrorLog /var/log/apache2/ssl_mydomain_error_log
        <IfModule log_config_module>
                TransferLog /var/log/apache2/ssl_mydomain_access_log
        </IfModule>

        SSLEngine on
        SSLCipherSuite ALL:!ADH:!EXPORT56:RC4+RSA:+HIGH:+MEDIUM:+LOW:+SSLv2:+EXP:+eNULL
        SSLCertificateFile /etc/apache2/ssl/mydomain.crt
        SSLCertificateKeyFile /etc/apache2/ssl/mydomain.key
        SSLCertificateChainFile /etc/ssl/cacert.pem
        <FilesMatch "\.(cgi|shtml|phtml|php)$">
                SSLOptions +StdEnvVars
        </FilesMatch>
        <Directory "/var/www/localhost/cgi-bin">
                SSLOptions +StdEnvVars
        </Directory>
        <IfModule log_config_module>
                CustomLog /var/log/apache2/ssl_mydomain_request_log \
                        "%t %h %{SSL_PROTOCOL}x %{SSL_CIPHER}x \"%r\" %b"
        </IfModule>
...

For exmaple if you need such certificate to connect your maven with a self installed nexus repositiory over https you can follow the article from ahoehma.

A more detailed description with some background information about the certificate creation can be found here.

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