Overview

Google Apps for Education (or any of the Google Apps) utilizes SAML 2.0 to provide an integration point for external authentication services.

Usage

The Google Apps for Education integration described here allows CAS to act as a miniaturized SAML2 identity provider, for deployments that may not be prepared to turn on and allow CAS to fully act as a SAML2 identity provider. This feature is deprecated and is scheduled to be removed in the future. It does not make much sense to turn on and use both features in CAS at the same time, as one outranks the other and it is likely that using both features in CAS simultaneously would interfere with the functionality of both. If you can, consider using the SAML2 identity provider functionality in CAS to handle this integration as you would any other SAML2 service provider.

Support is enabled by including the following dependency in the WAR overlay:

<dependency>
    <groupId>org.apereo.cas</groupId>
    <artifactId>cas-server-support-saml-googleapps</artifactId>
    <version>${cas.version}</version>
</dependency>

implementation "org.apereo.cas:cas-server-support-saml-googleapps:${project.'cas.version'}"

dependencyManagement {
    imports {
        mavenBom "org.apereo.cas:cas-server-support-bom:${project.'cas.version'}"
    }
}

dependencies {
    implementation "org.apereo.cas:cas-server-support-saml-googleapps"
}

dependencies {
    /*
    The following platform references should be included automatically and are listed here for reference only.
            
    implementation enforcedPlatform("org.apereo.cas:cas-server-support-bom:${project.'cas.version'}")
    implementation platform(org.springframework.boot.gradle.plugin.SpringBootPlugin.BOM_COORDINATES)
    */

    implementation "org.apereo.cas:cas-server-support-saml-googleapps"
}

Generate Public/Private Keys

The first step is to generate DSA/RSA public and private keys. These are used to sign and read the Assertions. After keys are created, the public key needs to be registered with Google.

The keys will also need to be available to the CAS application (but not publicly available over the Internet) via the classpath though any location accessible by the user running the web server instance and not served publicly to the Internet is acceptable. Thus, inside src/main/resources is nice because it is scoped to the web application but not normally served. /etc/cas/ is also fine as well and protects the key from being overwritten on deploy of a new CAS webapp version.

openssl genrsa -out private.key 1024
openssl rsa -pubout -in private.key -out public.key -inform PEM -outform DER
openssl pkcs8 -topk8 -inform PER -outform DER -nocrypt -in private.key -out private.p8
openssl req -new -x509 -key private.key -out x509.pem -days 365

The x509.pem file should be uploaded into Google Apps under Security/SSO.

The following settings and properties are available from the CAS configuration catalog:

_{The configuration settings listed below are tagged as Required in the CAS configuration metadata. This flag indicates that the presence of the setting may be needed to activate or affect the behavior of the CAS feature and generally should be reviewed, possibly owned and adjusted. If the setting is assigned a default value, you do not need to strictly put the setting in your copy of the configuration, but should review it nonetheless to make sure it matches your deployment expectations.}

cas.google-apps.private-key-location=file:/etc/cas/private.key

The private key location that is used to sign responses, etc. Deprecation: Since 6.2

org.apereo.cas.configuration.model.support.saml.googleapps.GoogleAppsProperties.

_{How can I configure this property?}

Configuration properties can be included and activated using the following strategies.

:information_source: Note

When possible, properties should be stored in lower-case kebab format, such as cas.property-name=value. The only possible exception to this rule is when naming actuator endpoints; The name of the actuator endpoints (i.e. ssoSessions) MUST remain in camelCase mode.

CAS properties can be specified using the Java configuration property syntax in any and all .properties files:

cas.google-apps.private-key-location=file:/etc/cas/private.key

This is the most common form of property configuration that is recognized by CAS, regardless of the actual property source, which might in fact be managed separately outside the CAS environment, by another system or cloud framework.

CAS properties can be specified using the YAML syntax:

cas: 
  google-apps: 
    private-key-location: 

Note that YAML is very specific about structure and indentation. Be sure to verify the correctness of the final result with your YAML validator of choice.

CAS properties can be passed to the CAS web application as system properties, when the application is launched:

java -Dcas.google-apps.private-key-location="file:/etc/cas/private.key" -jar build/libs/cas.war

The above example assumes that the CAS web application is packaged as cas.war with an embedded server container and can be found in the build/libs directory. Note the placement of the system property which must be specified before the CAS web application is launched.

CAS properties can specified as system environment variables before the CAS web application is launched:

export CAS_GOOGLE_APPS_PRIVATE_KEY_LOCATION="file:/etc/cas/private.key"

java -jar build/libs/cas.war

The above example assumes that the CAS web application is packaged as cas.war with an embedded server container and can be found in the build/libs directory.

CAS properties can be passed to the CAS web application as command-line arguments, when the application is launched:

java -jar build/libs/cas.war --cas.google-apps.private-key-location="file:/etc/cas/private.key"

The above example assumes that the CAS web application is packaged as cas.war with an embedded server container and can be found in the build/libs directory.

Deprecation status is ERRORwithout a replacement setting.

cas.google-apps.public-key-location=file:/etc/cas/public.key

The public key location that is also shared with google apps. Deprecation: Since 6.2

org.apereo.cas.configuration.model.support.saml.googleapps.GoogleAppsProperties.

_{How can I configure this property?}

Configuration properties can be included and activated using the following strategies.

:information_source: Note

CAS properties can be specified using the Java configuration property syntax in any and all .properties files:

cas.google-apps.public-key-location=file:/etc/cas/public.key

CAS properties can be specified using the YAML syntax:

cas: 
  google-apps: 
    public-key-location: 

Note that YAML is very specific about structure and indentation. Be sure to verify the correctness of the final result with your YAML validator of choice.

CAS properties can be passed to the CAS web application as system properties, when the application is launched:

java -Dcas.google-apps.public-key-location="file:/etc/cas/public.key" -jar build/libs/cas.war

CAS properties can specified as system environment variables before the CAS web application is launched:

export CAS_GOOGLE_APPS_PUBLIC_KEY_LOCATION="file:/etc/cas/public.key"

java -jar build/libs/cas.war

The above example assumes that the CAS web application is packaged as cas.war with an embedded server container and can be found in the build/libs directory.

CAS properties can be passed to the CAS web application as command-line arguments, when the application is launched:

java -jar build/libs/cas.war --cas.google-apps.public-key-location="file:/etc/cas/public.key"

The above example assumes that the CAS web application is packaged as cas.war with an embedded server container and can be found in the build/libs directory.

Deprecation status is ERRORwithout a replacement setting.

_{The configuration settings listed below are tagged as Optional in the CAS configuration metadata. This
flag indicates that the presence of the setting
is not immediately necessary in the end-user CAS configuration, because a default value is assigned or
the activation of the feature is not conditionally controlled by the setting value. You should only include this field in your
configuration if you need to modify the default value.}

cas.google-apps.key-algorithm=RSA

Signature algorithm used to generate keys. Deprecation: Since 6.2

org.apereo.cas.configuration.model.support.saml.googleapps.GoogleAppsProperties.

_{How can I configure this property?}

Configuration properties can be included and activated using the following strategies.

:information_source: Note

CAS properties can be specified using the Java configuration property syntax in any and all .properties files:

cas.google-apps.key-algorithm=RSA

CAS properties can be specified using the YAML syntax:

cas: 
  google-apps: 
    key-algorithm: 

Note that YAML is very specific about structure and indentation. Be sure to verify the correctness of the final result with your YAML validator of choice.

CAS properties can be passed to the CAS web application as system properties, when the application is launched:

java -Dcas.google-apps.key-algorithm="RSA" -jar build/libs/cas.war

CAS properties can specified as system environment variables before the CAS web application is launched:

export CAS_GOOGLE_APPS_KEY_ALGORITHM="RSA"

java -jar build/libs/cas.war

The above example assumes that the CAS web application is packaged as cas.war with an embedded server container and can be found in the build/libs directory.

CAS properties can be passed to the CAS web application as command-line arguments, when the application is launched:

java -jar build/libs/cas.war --cas.google-apps.key-algorithm="RSA"

The above example assumes that the CAS web application is packaged as cas.war with an embedded server container and can be found in the build/libs directory.

Deprecation status is ERRORwithout a replacement setting.