Zimbra Single Sign-On using SAML with SimpleSAMLphp
Did you know that Zimbra support SAML single sign on? SAML is an open standard that allows you to have a single login page for all applications in your organization. SAML is a Zimbra Network Edition feature. Once you have set-up your SAML portal you can easily add Multi Factor Authentication.
Set up Zimbra App
In SAML terms applications are called Service Providers or SP’s. The service that provides your user database and takes care of yuor authentication is in SAML terms called Identity Provider or IDP. Usually you only have one IDP and as many SP’s as you have applications. In this example we will set-up Zimbra as a SAML SP and use SimpleSAMLphp as IDP. This is the configuration needed on SimpleSAMLphp:
$metadata['https://zm-zimbra9.barrydegraaff.tk/service/extension/samlreceiver'] = array( 'simplesaml.attributes' => true, 'debug' => TRUE, 'AssertionConsumerService' => 'https://zm-zimbra9.barrydegraaff.tk/service/extension/samlreceiver', 'SingleLogoutService' => 'https://zm-zimbra9.barrydegraaff.tk/service/extension/samlslo', 'NameIDFormat' => 'urn:oasis:names:tc:SAML:1.1:nameid-format:emailAddress', 'authproc' => array ( 10 => array( 'class' => 'saml:AttributeNameID', 'attribute' => 'emailAddress', 'Format' => 'urn:oasis:names:tc:SAML:1.1:nameid-format:emailAddress', ), ) );
You will also need to get the X.509 public certificate that is used for signing the SAML request from th IDP to Zimbra. You will need to download it and save it on your Zimbra server. This guide will assume you store your cert in
/tmp/idpcert.pem, don’t forget to
chown zimbra:zimbra /tmp/idpcert.pem. If you followed the SimpleSAMLphp setup guide you can find the certificate at
Set up Zimbra
Add the file
/opt/zimbra/conf/saml/saml-config.properties to configure SAML in Zimbra add the contents:
# Issuer saml_sp_entity_id=https://zm-zimbra9.barrydegraaff.tk/service/extension/samlreceiver # Login receiver for the service provider saml_acs=https://zm-zimbra9.barrydegraaff.tk/service/extension/samlreceiver # Name ID format for the IDP to use in the SAMLResponse saml_name_id_format=urn:oasis:names:tc:SAML:1.1:nameid-format:emailAddress # Date format for issue instant saml_date_format_instant=yyyy-MM-dd'T'HH:mm:ss'Z' # Identity provider login endpoint for redirect method saml_redirect_login_destination=https://saml.barrydegraaff.tk/simplesaml/saml2/idp/SSOService.php?spentityid=https://zm-zimbra9.barrydegraaff.tk/service/extension/samlreceiver # Identity provider login endpoint for POST method saml_post_login_destination= # Identity provider logout endpoint for redirect method saml_redirect_logout_destination=https://saml.barrydegraaff.tk/simplesaml/saml2/idp/SingleLogoutService.php # Identity provider logout endpoint for POST method saml_post_logout_destination= # Logout redirect page if we are the landing page logout endpoint saml_landing_logout_redirect_url=/ # Disable the audience path check saml_skip_audience_restriction=true # URL to send the user with error_code, error_msg query params. Default results in HTTP error code pages. saml_error_redirect_url= # The SAML logout document encoding, and SAML login receiver parameter encoding. saml_document_encoding=ASCII # Set to true to disable the audience path check. saml_skip_audience_restriction=false # The redirect location to send the user if their Zimbra account is not active. saml_inactive_account_redirect_url
From the command line as user root copy the samlextn.jar and set up the IDP certificate like this:
mkdir /opt/zimbra/lib/ext/saml cp /opt/zimbra/extensions-network-extra/saml/samlextn.jar /opt/zimbra/lib/ext/saml/ su zimbra cat /tmp/idpcert.pem |xargs -0 zmprov md exampledomain.com zimbraMyoneloginSamlSigningCert zmprov mcf zimbraCsrfRefererCheckEnabled FALSE zmmailboxdctl restart
Your user accounts must be manually created in Zimbra and be available in your IDP user database. It is important that the E-mail attribute in your IDP is set exactly the same as the Zimbra account name. Or the user will not be able to log-in. If it does not work run a
tail -f /opt/zimbra/log/* while doing the authentication request and dig through to log to find out what the issue may be. Keywords to grep for: SAML, Audience and assertion.