Git - SAML2 Metadata Management
Metadata documents may also be stored in and fetched from Git repositories. This may specially be used to avoid copying metadata
files across CAS nodes in a cluster, particularly where one needs to deal with more than a few bilateral SAML integrations.
Metadata documents are stored as XML files, and their signing certificate, optionally, is expected to be found in a .pem
file by the same name in the repository. (i.e. SP.xml
’s certificate can be found in SP.pem
).
Support is enabled by including the following module in the overlay:
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<dependency>
<groupId>org.apereo.cas</groupId>
<artifactId>cas-server-support-saml-idp-metadata-git</artifactId>
<version>${cas.version}</version>
</dependency>
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implementation "org.apereo.cas:cas-server-support-saml-idp-metadata-git:${project.'cas.version'}"
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dependencyManagement {
imports {
mavenBom "org.apereo.cas:cas-server-support-bom:${project.'cas.version'}"
}
}
dependencies {
implementation "org.apereo.cas:cas-server-support-saml-idp-metadata-git"
}
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dependencies {
/*
The following platform references should be included automatically and are listed here for reference only.
implementation enforcedPlatform("org.apereo.cas:cas-server-support-bom:${project.'cas.version'}")
implementation platform(org.springframework.boot.gradle.plugin.SpringBootPlugin.BOM_COORDINATES)
*/
implementation "org.apereo.cas:cas-server-support-saml-idp-metadata-git"
}
SAML service definitions must then be designed as follows to allow CAS to fetch metadata documents from Git repositories:
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{
"@class" : "org.apereo.cas.support.saml.services.SamlRegisteredService",
"serviceId" : "the-entity-id-of-the-sp",
"name" : "SAMLService",
"id" : 1,
"description" : "A Git-based metadata resolver",
"metadataLocation" : "git://"
}
Give the above definition, the expectation is that the git repository
contains a SAMLService.xml
file which may optionally also be accompanied by a SAMLService.pem
file.
The metadata location in the registration record above needs to be specified as git://
to signal to CAS that
SAML metadata for registered service provider must be fetched from Git repositories defined in CAS configuration.
The following settings and properties are available from the CAS configuration catalog:
cas.authn.saml-idp.metadata.git.clone-directory.location=
The location of the resource. Resources can be URLs, or files found either on the classpath or outside somewhere in the file system. In the event the configured resource is a Groovy script, specially if the script set to reload on changes, you may need to adjust the total number ofinotify instances. On Linux, you may need to add the following line to /etc/sysctl.conf : fs.inotify.max_user_instances = 256 . You can check the current value via cat /proc/sys/fs/inotify/max_user_instances . In situations and scenarios where CAS is able to automatically watch the underlying resource for changes and detect updates and modifications dynamically, you may be able to specify the following setting as either an environment variable or system property with a value of false to disable the resource watcher: org.apereo.cas.util.io.PathWatcherService .
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cas.authn.saml-idp.metadata.git.crypto.encryption.key=
The encryption key is a JWT whose length is defined by the encryption key size setting. This setting supports the Spring Expression Language.
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cas.authn.saml-idp.metadata.git.crypto.signing.key=
The signing key is a JWT whose length is defined by the signing key size setting. This setting supports the Spring Expression Language.
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cas.authn.saml-idp.metadata.git.private-key.location=
The location of the resource. Resources can be URLs, or files found either on the classpath or outside somewhere in the file system. In the event the configured resource is a Groovy script, specially if the script set to reload on changes, you may need to adjust the total number ofinotify instances. On Linux, you may need to add the following line to /etc/sysctl.conf : fs.inotify.max_user_instances = 256 . You can check the current value via cat /proc/sys/fs/inotify/max_user_instances . In situations and scenarios where CAS is able to automatically watch the underlying resource for changes and detect updates and modifications dynamically, you may be able to specify the following setting as either an environment variable or system property with a value of false to disable the resource watcher: org.apereo.cas.util.io.PathWatcherService .
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cas.authn.saml-idp.metadata.git.active-branch=master
The branch to checkout and activate, defaults to This setting supports the Spring Expression Language.
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cas.authn.saml-idp.metadata.git.branches-to-clone=*
If the repository is to be cloned, this will allow a select list of branches to be fetched. List the branch names separated by commas or use
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cas.authn.saml-idp.metadata.git.repository-url=
The address of the git repository. Could be a URL or a file-system path. This setting supports the Spring Expression Language.
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cas.authn.saml-idp.metadata.git.crypto.alg=
The signing/encryption algorithm to use.
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cas.authn.saml-idp.metadata.git.crypto.enabled=true
Whether crypto operations are enabled.
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cas.authn.saml-idp.metadata.git.crypto.encryption.key-size=512
The encryption key size.
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cas.authn.saml-idp.metadata.git.crypto.signing.key-size=512
The signing key size.
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cas.authn.saml-idp.metadata.git.crypto.strategy-type=ENCRYPT_AND_SIGN
Control the cipher sequence of operations. The accepted values are:
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cas.authn.saml-idp.metadata.git.clear-existing-identities=false
When establishing an ssh session, determine if default identities loaded on the machine should be excluded/removed and identity should only be limited to those loaded from given keys.
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cas.authn.saml-idp.metadata.git.http-client-type=JDK
Implementation of HTTP client to use when doing git operations via http/https. The jgit library sets the connection factory statically (globally) so this property should be set to the same value for all git repositories (services, saml, etc). Not doing so might result in one connection factory being used for clone and another for subsequent fetches. Available values are as follows:
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cas.authn.saml-idp.metadata.git.idp-metadata-enabled=false
Whether identity provider metadata artifacts are expected to be found in the database.
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cas.authn.saml-idp.metadata.git.password=
Password used to access or push to the repository.
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cas.authn.saml-idp.metadata.git.private-key-passphrase=
Password for the SSH private key.
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cas.authn.saml-idp.metadata.git.push-changes=false
Decide whether changes should be pushed back into the remote repository.
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cas.authn.saml-idp.metadata.git.rebase=false
Whether to rebase on pulls.
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cas.authn.saml-idp.metadata.git.sign-commits=false
Whether commits should be signed.
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cas.authn.saml-idp.metadata.git.ssh-session-password=
As with using SSH with public keys, an SSH session with
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cas.authn.saml-idp.metadata.git.strict-host-key-checking=true
Whether on not to turn on strict host key checking. true will be "yes", false will be "no", "ask" not supported.
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cas.authn.saml-idp.metadata.git.timeout=PT10S
Timeout for git operations such as push and pull in seconds. This settings supports the
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cas.authn.saml-idp.metadata.git.username=
Username used to access or push to the repository.
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cas.authn.saml-idp.metadata.git.crypto.encryption.key=
The encryption key is a JWT whose length is defined by the encryption key size setting. This setting supports the Spring Expression Language.
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cas.authn.saml-idp.metadata.git.crypto.signing.key=
The signing key is a JWT whose length is defined by the signing key size setting. This setting supports the Spring Expression Language.
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cas.authn.saml-idp.metadata.git.crypto.alg=
The signing/encryption algorithm to use.
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cas.authn.saml-idp.metadata.git.crypto.enabled=true
Whether crypto operations are enabled.
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cas.authn.saml-idp.metadata.git.crypto.encryption.key-size=512
The encryption key size.
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cas.authn.saml-idp.metadata.git.crypto.signing.key-size=512
The signing key size.
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cas.authn.saml-idp.metadata.git.crypto.strategy-type=ENCRYPT_AND_SIGN
Control the cipher sequence of operations. The accepted values are:
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This CAS feature is able to accept signing and encryption crypto keys. In most scenarios if keys are not provided, CAS will auto-generate them. The following instructions apply if you wish to manually and beforehand create the signing and encryption keys.
Note that if you are asked to create a JWK of a certain size for the key, you are to use the following set of commands to generate the token:
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wget https://raw.githubusercontent.com/apereo/cas/master/etc/jwk-gen.jar
java -jar jwk-gen.jar -t oct -s [size]
The outcome would be similar to:
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{
"kty": "oct",
"kid": "...",
"k": "..."
}
The generated value for k
needs to be assigned to the relevant CAS settings. Note that keys generated via
the above algorithm are processed by CAS using the Advanced Encryption Standard (AES
) algorithm which is a
specification for the encryption of electronic data established by the U.S. National Institute of Standards and Technology.
Configuration Metadata
The collection of configuration properties listed in this section are automatically generated from the CAS source and components that contain the actual field definitions, types, descriptions, modules, etc. This metadata may not always be 100% accurate, or could be lacking details and sufficient explanations.
Be Selective
This section is meant as a guide only. Do NOT copy/paste the entire collection of settings into your CAS configuration; rather pick only the properties that you need. Do NOT enable settings unless you are certain of their purpose and do NOT copy settings into your configuration only to keep them as reference. All these ideas lead to upgrade headaches, maintenance nightmares and premature aging.
YAGNI
Note that for nearly ALL use cases, declaring and configuring properties listed here is sufficient. You should NOT have to explicitly massage a CAS XML/Java/etc configuration file to design an authentication handler, create attribute release policies, etc. CAS at runtime will auto-configure all required changes for you. If you are unsure about the meaning of a given CAS setting, do NOT turn it on without hesitation. Review the codebase or better yet, ask questions to clarify the intended behavior.
Naming Convention
Property names can be specified in very relaxed terms. For instance cas.someProperty
, cas.some-property
, cas.some_property
are all valid names. While all
forms are accepted by CAS, there are certain components (in CAS and other frameworks used) whose activation at runtime is conditional on a property value, where
this property is required to have been specified in CAS configuration using kebab case. This is both true for properties that are owned by CAS as well as those
that might be presented to the system via an external library or framework such as Spring Boot, etc.
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.
Settings and properties that are controlled by the CAS platform directly always begin with the prefix cas
. All other settings are controlled and provided
to CAS via other underlying frameworks and may have their own schemas and syntax. BE CAREFUL with
the distinction. Unrecognized properties are rejected by CAS and/or frameworks upon which CAS depends. This means if you somehow misspell a property definition
or fail to adhere to the dot-notation syntax and such, your setting is entirely refused by CAS and likely the feature it controls will never be activated in the
way you intend.
Validation
Configuration properties are automatically validated on CAS startup to report issues with configuration binding, specially if defined CAS settings cannot be recognized or validated by the configuration schema. Additional validation processes are also handled via Configuration Metadata and property migrations applied automatically on startup by Spring Boot and family.
Indexed Settings
CAS settings able to accept multiple values are typically documented with an index, such as cas.some.setting[0]=value
. The index [0]
is meant to be
incremented by the adopter to allow for distinct multiple configuration blocks.
Reloading Service Provider Metadata
By default, SAML2 service provider metadata is pulled from git repositories when there is a need to resolve and fetch metadata. You could also configure CAS to activate and turn on a background job to pull metadata periodically using a background scheduler.
The following settings and properties are available from the CAS configuration catalog:
cas.authn.saml-idp.metadata.git.schedule.cron-expression=
A cron-like expression, extending the usual UN*X definition to include triggers on the second, minute, hour, day of month, month, and day of week. For example,
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cas.authn.saml-idp.metadata.git.schedule.cron-time-zone=
A time zone for which the cron expression will be resolved. By default, this attribute is empty (i.e. the scheduler's time zone will be used).
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cas.authn.saml-idp.metadata.git.schedule.enabled=true
Whether scheduler should be enabled to schedule the job to run.
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cas.authn.saml-idp.metadata.git.schedule.enabled-on-host=.*
Overrides This settings supports regular expression patterns. [?].
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cas.authn.saml-idp.metadata.git.schedule.repeat-interval=PT2M
String representation of a repeat interval of re-loading data for a data store implementation. This is the timeout between consecutive job’s executions. This settings supports the
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cas.authn.saml-idp.metadata.git.schedule.start-delay=PT15S
String representation of a start delay of loading data for a data store implementation. This is the delay between scheduler startup and first job’s execution This settings supports the
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Configuration Metadata
The collection of configuration properties listed in this section are automatically generated from the CAS source and components that contain the actual field definitions, types, descriptions, modules, etc. This metadata may not always be 100% accurate, or could be lacking details and sufficient explanations.
Be Selective
This section is meant as a guide only. Do NOT copy/paste the entire collection of settings into your CAS configuration; rather pick only the properties that you need. Do NOT enable settings unless you are certain of their purpose and do NOT copy settings into your configuration only to keep them as reference. All these ideas lead to upgrade headaches, maintenance nightmares and premature aging.
YAGNI
Note that for nearly ALL use cases, declaring and configuring properties listed here is sufficient. You should NOT have to explicitly massage a CAS XML/Java/etc configuration file to design an authentication handler, create attribute release policies, etc. CAS at runtime will auto-configure all required changes for you. If you are unsure about the meaning of a given CAS setting, do NOT turn it on without hesitation. Review the codebase or better yet, ask questions to clarify the intended behavior.
Naming Convention
Property names can be specified in very relaxed terms. For instance cas.someProperty
, cas.some-property
, cas.some_property
are all valid names. While all
forms are accepted by CAS, there are certain components (in CAS and other frameworks used) whose activation at runtime is conditional on a property value, where
this property is required to have been specified in CAS configuration using kebab case. This is both true for properties that are owned by CAS as well as those
that might be presented to the system via an external library or framework such as Spring Boot, etc.
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.
Settings and properties that are controlled by the CAS platform directly always begin with the prefix cas
. All other settings are controlled and provided
to CAS via other underlying frameworks and may have their own schemas and syntax. BE CAREFUL with
the distinction. Unrecognized properties are rejected by CAS and/or frameworks upon which CAS depends. This means if you somehow misspell a property definition
or fail to adhere to the dot-notation syntax and such, your setting is entirely refused by CAS and likely the feature it controls will never be activated in the
way you intend.
Validation
Configuration properties are automatically validated on CAS startup to report issues with configuration binding, specially if defined CAS settings cannot be recognized or validated by the configuration schema. Additional validation processes are also handled via Configuration Metadata and property migrations applied automatically on startup by Spring Boot and family.
Indexed Settings
CAS settings able to accept multiple values are typically documented with an index, such as cas.some.setting[0]=value
. The index [0]
is meant to be
incremented by the adopter to allow for distinct multiple configuration blocks.
Identity Provider Metadata
Metadata artifacts that belong to CAS as a SAML2 identity provider may also be managed and stored via Git. Artifacts such as the metadata, signing and encryption keys, etc are kept on the file-system in distinct directory locations inside the repository and data is pushed to or pulled from git repositories on demand.
Per Service
Identity provider metadata, certificates and keys can also be defined on a per-service basis to override the global defaults.
Metadata documents that would be applicable to a service definition need to adjust the appliesTo
field in the metadata
document, which is used to construct the directory path to metadata artifacts.