Unit 6: Service certificates¶
You probably noticed that the web service was not hosted over HTTPS, so there is no TLS-based authentication or confidentiality. In this unit, we will issue an X.509 certificate for the web service via the Certmonger program.
Certmonger supports multiple CAs including FreeIPA’s CA, and can
generate keys, issue certificate requests, track certificates, and
renew tracked certificates when the expiration time approaches.
Will also use
mod_ssl with Apache.
Issue the service certificate¶
Let’s start by confirming that the HTTP service does not yet have a certificate:
[client]$ ipa service-show HTTP/client.ipademo.local Principal name: HTTP/client.ipademo.local@IPADEMO.LOCAL Principal alias: HTTP/client.ipademo.local@IPADEMO.LOCAL Keytab: True Managed by: client.ipademo.local
Enable and start Certmonger:
[client]$ sudo systemctl enable --now certmonger Created symlink /etc/systemd/system/multi-user.target.wants/certmonger.service → /usr/lib/systemd/system/certmonger.service.
Now let’s request a certificate. We will generate keys and store
certificates in the NSS database at
[client]$ sudo ipa-getcert request \ -f /etc/pki/tls/certs/app.crt \ -k /etc/pki/tls/private/app.key \ -K HTTP/client.ipademo.local \ -D client.ipademo.local New signing request "20180603185400" added.
Let’s break down some of those command arguments.
Path to private key (Certmonger will generate it)
Path to certificate (where it will be saved after being issued)
Kerberos service principal; because different kinds of services may be accessed at one hostname, this argument tells Certmonger which service principal is the subject
Requests the given domain name to appear in the Subject Alternative Name (SAN) extension; today the Common Name (CN) field is no longer used by browsers so the SAN value is essential
Another important option is
-N <subject-name>. It defaults to
the system hostname, which in our case (
Let’s check the status of our certificate request using the tracking
identifier given in the
ipa-getcert request output:
[client]$ sudo getcert list -i 20180603185400 Number of certificates and requests being tracked: 1. Request ID '20180603185400': status: MONITORING stuck: no key pair storage: type=FILE,location='/etc/pki/tls/private/app.key' certificate: type=FILE,location='/etc/pki/tls/certs/app.crt' CA: IPA issuer: CN=Certificate Authority,O=IPADEMO.LOCAL subject: CN=client.ipademo.local,O=IPADEMO.LOCAL expires: 2020-06-03 18:54:00 UTC dns: client.ipademo.local principal name: HTTP/client.ipademo.local@IPADEMO.LOCAL key usage: digitalSignature,nonRepudiation,keyEncipherment,dataEncipherment eku: id-kp-serverAuth,id-kp-clientAuth pre-save command: post-save command: track: yes auto-renew: yes
Confirm that the certificate was issued and that Certmonger is now
MONITORING the certificate and will
auto-renew it when it is
close to expiration. Now if you run
ipa service-show, you will
see a number of attributes related to the certificate, including the
certificate itself. Can you work out how to save the PEM-encoded
certificate to a file?
Set up TLS for Apache¶
Now we can reconfigure Apache to serve our app over TLS. Update
app.conf to listen on port 443 and add the SSL directives:
... Listen 443 <VirtualHost *:443> SSLEngine on SSLCertificateFile "/etc/pki/tls/certs/app.crt" SSLCertificateKeyFile "/etc/pki/tls/private/app.key" ServerName client.ipademo.local ...
Restart Apache and make a request to the app over HTTPS:
[client]$ sudo systemctl restart httpd [client]$ curl -u : --negotiate https://client.ipademo.local LOGGED IN AS: alice@IPADEMO.LOCAL REMOTE_* REQUEST VARIABLES: REMOTE_USER: alice@IPADEMO.LOCAL REMOTE_USER_GROUP_1: ipausers REMOTE_USER_GROUP_2: sysadmin REMOTE_USER_GROUP_N: 2 REMOTE_USER_FIRSTNAME: Alice REMOTE_USER_LASTNAME: Alice REMOTE_USER_MAIL: email@example.com REMOTE_ADDR: 192.168.33.20 REMOTE_PORT: 51876