APEREO CASDocumentation

Enterprise Authentication for All Earthlings and Beyond

Identity, Single Sign-On and Access Management
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SPNEGO Authentication

SPNEGO is an authentication technology that is primarily used to provide transparent CAS authentication to browsers running on Windows running under Active Directory domain credentials. There are three actors involved: the client, the CAS server, and the Active Directory Domain Controller/KDC.

  1. Client sends CAS: HTTP GET to CAS for cas protected page
  2. CAS responds: HTTP 401 - Access Denied WWW-Authenticate: Negotiate
  3. Client sends ticket request: Kerberos(KRB_TGS_REQ) Requesting ticket for HTTP/cas.example.com@REALM
  4. Kerberos KDC responds: Kerberos(KRB_TGS_REP) Granting ticket for HTTP/cas.example.com@REALM
  5. Client sends CAS: HTTP GET Authorization: Negotiate w/SPNEGO Token
  6. CAS responds: HTTP 200 - OK WWW-Authenticate w/SPNEGO response + requested page.

The above interaction occurs only for the first request, when there is no CAS SSO session. Once CAS grants a ticket-granting ticket, the SPNEGO process will not happen again until the CAS ticket expires.

Requirements

  • Client is logged in to a Windows Active Directory domain.
  • Supported browser.
  • CAS is running MIT kerberos against the AD domain controller.
:information_source: JCE Requirement

It's safe to make sure you have the proper JCE bundle installed in your Java environment that is used by CAS, specially if you need to consume encrypted payloads issued by ADFS. Be sure to pick the right version of the JCE for your Java version. Java versions can be detected via the java -version command.

:information_source: Large Kerberos Tickets

If organization users have large kerberos tickets, likely cause by being a member of a large number of groups, the Tomcat connector will need to have the maxHttpHeaderSize value increased from the default amount to allow the ticket to be passed to the CAS Server application.

Components

SPNEGO support is enabled by including the following dependency in the WAR overlay:

Show in CAS Initializr Generate CAS Server WAR Overlay 


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





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implementation "org.apereo.cas:cas-server-support-spnego-webflow:${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-spnego-webflow"
}





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dependencies {
    /*
        The following platform references are included automatically and are listed 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-spnego-webflow"
}

JCIFS SDK

Note that jcifs-ext library is no longer published to a public Maven repository. This means that you will need to download the necessary JAR files and include them in your build configuration. The SDK may be downloaded from the CAS codebase. Then, assuming the SDK is placed inside a lib directory of the WAR overlay directory, it can be referenced in the build configuration as such:



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implementation files("${projectDir}/lib/jcifs-ext.jar")

Configuration

The following steps are required to turn on the SPNEGO functionality.

Create SPN Account

Create an Active Directory account for the Service Principal Name (SPN) and record the username. Password will be overwritten by the next step.

Create Keytab File

The keytab file enables a trust link between the CAS server and the Key Distribution Center (KDC); an Active Directory domain controller serves the role of KDC in this context. The ktpass tool is used to generate the keytab file, which contains a cryptographic key. Be sure to execute the command from an Active Directory domain controller as administrator (a member of domain administrators will not be able to use ktpass successfully).

Example:



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C:\Users\administrator.DOMAIN>ktpass /out myspnaccount.keytab /princ HTTP/cas.example.com@REALM /pass * /mapuser domain-account@YOUR.REALM /ptype KRB5_NT_PRINCIPAL /crypto AES256-SHA1
Targeting domain controller: DC.YOUR.REALM
Successfully mapped HTTP/cas.example.com to domain-account.
Type the password for HTTP/cas.example.com:
Type the password again to confirm:
Password successfully set!
Key created.
Output keytab to myspnaccount.keytab:
Keytab version: 0x502
keysize 93 HTTP/cas.example.com@REALM ptype 1 (KRB5_NT_PRINCIPAL) vno 5 etype 0x12 (AES256-SHA1) keylength 32
(0x00112233445566778899aabbccddeeff00112233445566778899aabbccddeeff)

Using ktpass requires Active Directory admin permissions. If that is not an option, you may be able to use ktab.exe from %JAVA_HOME%\bin\ktab.exe that is provided by the JDK:



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%JAVA_HOME%\bin\ktab.exe -a service_xxx -n 0 -k cas.keytab

-k specifies key tab output file name and -n 0 specifies the KNVO number if available and found for the user account. This value may match the msDS-KeyVersionNumber on the user account.

Also note that the keytab file must be regenerated after password changes, if any.

Test SPN Account

Install and configure MIT Kerberos V on the CAS server host(s). The following sample krb5.conf file may be used as a reference.



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[logging]
 default = FILE:/var/log/krb5libs.log
 kdc = FILE:/var/log/krb5kdc.log
 admin_server = FILE:/var/log/kadmind.log

[libdefaults]
 ticket_lifetime = 24000
 default_realm = YOUR.REALM.HERE
 default_keytab_name = /home/cas/kerberos/myspnaccount.keytab
 dns_lookup_realm = false
 dns_lookup_kdc = false
 default_tkt_enctypes = rc4-hmac
 default_tgs_enctypes = rc4-hmac

[realms]
 YOUR.REALM.HERE = {
  kdc = your.kdc.your.realm.here:88
 }

[domain_realm]
 .your.realm.here = YOUR.REALM.HERE
 your.realm.here = YOUR.REALM.HERE

It is important to note that myspnaccount.keytab is declared as default keytab, otherwise CAS may not be able to find it and will raise an exception similar to



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KrbException: Invalid argument (400) - Cannot find key of appropriate type to decrypt AP REP -RC4 with HMAC`

Then verify that your are able to read the keytab file:



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klist -k
Keytab name: FILE:/home/cas/kerberos/myspnaccount.keytab
KVNO Principal
---- --------------------------------------------------------------------------
   3 HTTP/cas.example.com@REALM

Then verify that your are able to use the keytab file:



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kinit -k HTTP/cas.example.com@REALM
klist
Ticket cache: FILE:/tmp/krb5cc_999
Default principal: HTTP/cas.example.com@REALM

Valid starting       Expires              Service principal
12/08/2016 10:52:00  12/08/2016 20:52:00  krbtgt/REALM@REALM
    renew until 12/08/2016 20:52:00

Browser Configuration

  • Internet Explorer - Enable Integrated Windows Authentication and add the CAS server URL to the Local Intranet zone.
  • Firefox - Set the network.negotiate-auth.trusted-uris configuration parameter in about:config to the CAS server URL, e.g. https://cas.example.com.

Authentication Configuration

Make sure you have at least specified the JCIFS Service Principal in the CAS configuration.

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

cas.authn.spnego.ldap.base-dnBase DN to use.
no default
Required

Base DN to use. There may be scenarios where different parts of a single LDAP tree could be considered as base-dns. Rather than duplicating the LDAP configuration block for each individual base-dn, each entry can be specified and joined together using a special delimiter character. The user DN is retrieved using the combination of all base-dn and DN resolvers in the order defined. DN resolution should fail if multiple DNs are found. Otherwise the first DN found is returned. Usual syntax is: subtreeA,dc=example,dc=net|subtreeC,dc=example,dc=net.

Type
String
Default
none
Defined by
SpnegoLdapProperties
cas.authn.spnego.ldap.bind-credentialThe bind credential to use when connecting to LDAP.
no default
Required

The bind credential to use when connecting to LDAP.

Type
String
Default
none
Defined by
SpnegoLdapProperties
cas.authn.spnego.ldap.bind-dnThe bind DN to use when connecting to LDAP.
no default
Required
The bind DN to use when connecting to LDAP. LDAP connection configuration injected into the LDAP connection pool can be initialized with the following parameters:
  • bindDn/bindCredential provided - Use the provided credentials to bind when initializing connections.
  • bindDn/bindCredential set to * - Use a fast-bind strategy to initialize the pool.
  • bindDn/bindCredential set to blank - Skip connection initializing; perform operations anonymously.
  • SASL mechanism provided - Use the given SASL mechanism to bind when initializing connections.
Type
String
Default
none
Defined by
SpnegoLdapProperties
cas.authn.spnego.ldap.ldap-urlThe LDAP url to the server.
no default
Required

The LDAP url to the server. More than one may be specified, separated by space and/or comma.

Type
String
Default
none
Defined by
SpnegoLdapProperties
cas.authn.spnego.ldap.search-filterUser filter to use for searching.
no default
Required

User filter to use for searching. Syntax is cn={user} or cn={0}.

You may also provide an external groovy script in the syntax of file:/path/to/GroovyScript.groovy to fully build the final filter template dynamically.

Type
String
Default
none
Defined by
SpnegoLdapProperties
cas.authn.spnego.principal-transformation.groovy.locationThe location of the resource.
no default
Required

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, especially if the script is set to reload on changes, you may need to adjust the total number of inotify 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.

Type
Resource
Default
none
Defined by
GroovyPrincipalTransformationProperties
cas.authn.spnego.principal.principal-transformation.groovy.locationThe location of the resource.
no default
Required

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, especially if the script is set to reload on changes, you may need to adjust the total number of inotify 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.

Type
Resource
Default
none
Defined by
GroovyPrincipalTransformationProperties
cas.authn.spnego.properties[0].jcifs-service-principalThe Jcifs service principal.
HTTP/cas.example.com@EXAMPLE.COM
Required

The Jcifs service principal.

Type
String
Default
HTTP/cas.example.com@EXAMPLE.COM
Defined by
SpnegoAuthenticationProperties
cas.authn.spnego.alternative-remote-host-attributeAlternative header name to use in order to find the host address.
alternateRemoteHeader

Alternative header name to use in order to find the host address.

Type
String
Default
alternateRemoteHeader
Defined by
SpnegoProperties
cas.authn.spnego.dns-timeoutWhen validating clients, specifies the DNS timeout used to look up an address.
PT2S
Duration

When validating clients, specifies the DNS timeout used to look up an address.

Type
String
Default
PT2S
Defined by
SpnegoProperties
cas.authn.spnego.host-name-client-action-strategyThe bean id of a webflow action whose job is to evaluate the client host to see if the request is authorized for spnego.
hostnameSpnegoClientAction

The bean id of a webflow action whose job is to evaluate the client host to see if the request is authorized for spnego. Supported strategies include hostnameSpnegoClientAction where CAS checks to see if the request’s remote hostname matches a predefine pattern. and ldapSpnegoClientAction where CAS checks an LDAP instance for the remote hostname, to locate a pre-defined attribute whose mere existence would allow the webflow to resume to SPNEGO.

Type
String
Default
hostnameSpnegoClientAction
Defined by
SpnegoProperties
cas.authn.spnego.host-name-pattern-stringA regex pattern that indicates whether the client host name is allowed for spnego.
.+
Regex

A regex pattern that indicates whether the client host name is allowed for spnego.

Type
String
Default
.+
Defined by
SpnegoProperties
cas.authn.spnego.ips-to-check-patternA regex pattern that indicates whether the client IP is allowed for spnego.
127.+
Regex

A regex pattern that indicates whether the client IP is allowed for spnego.

Type
String
Default
127.+
Defined by
SpnegoProperties
cas.authn.spnego.ldap.allow-multiple-dnsWhether search/query results are allowed to match on multiple DNs, or whether a single unique DN is expected for the result.
false

Whether search/query results are allowed to match on multiple DNs, or whether a single unique DN is expected for the result.

Type
Boolean
Default
false
Defined by
SpnegoLdapProperties
cas.authn.spnego.ldap.allow-multiple-entriesSet if multiple Entries are allowed.
false

Set if multiple Entries are allowed.

Type
Boolean
Default
false
Defined by
SpnegoLdapProperties
cas.authn.spnego.ldap.binary-attributesIndicate the collection of attributes that are to be tagged and processed as binary attributes by the underlying search resolver.
no default

Indicate the collection of attributes that are to be tagged and processed as binary attributes by the underlying search resolver.

Type
List<String>
Default
none
Defined by
SpnegoLdapProperties
cas.authn.spnego.ldap.block-wait-timeThe length of time the pool will block.
PT3S
Duration

The length of time the pool will block. By default the pool will block indefinitely and there is no guarantee that waiting threads will be serviced in the order in which they made their request. This option should be used with a blocking connection pool when you need to control the exact number of connections that can be created

Type
String
Default
PT3S
Defined by
SpnegoLdapProperties
cas.authn.spnego.ldap.connect-timeoutSets the maximum amount of time that connects will block.
PT5S
Duration

Sets the maximum amount of time that connects will block.

Type
String
Default
PT5S
Defined by
SpnegoLdapProperties
cas.authn.spnego.ldap.connection-strategyIf multiple URLs are provided as the ldapURL this describes how each URL will be processed.
no default
If multiple URLs are provided as the ldapURL this describes how each URL will be processed.
  • ACTIVE_PASSIVE First LDAP will be used for every request unless it fails and then the next shall be used.
  • ROUND_ROBIN For each new connection the next url in the list will be used.
  • RANDOM For each new connection a random LDAP url will be selected.
  • DNS_SRV LDAP urls based on DNS SRV records of the configured/given LDAP url will be used.
Type
String
Default
none
Defined by
SpnegoLdapProperties
cas.authn.spnego.ldap.disable-poolingWhether to use a pooled connection factory in components.
false

Whether to use a pooled connection factory in components.

Type
Boolean
Default
false
Defined by
SpnegoLdapProperties
cas.authn.spnego.ldap.fail-fastAttempt to populate the connection pool early on startup and fail quickly if something goes wrong.
true

Attempt to populate the connection pool early on startup and fail quickly if something goes wrong.

Type
Boolean
Default
true
Defined by
SpnegoLdapProperties
cas.authn.spnego.ldap.follow-referralsSet if search referrals should be followed.
true

Set if search referrals should be followed.

Type
Boolean
Default
true
Defined by
SpnegoLdapProperties
cas.authn.spnego.ldap.hostname-verifierHostname verification options.
DEFAULT
Hostname verification options. Available values are as follows:
  • DEFAULT: Default option, forcing verification.
  • ANY: Skip hostname verification and allow all.
Type
AbstractLdapProperties.LdapHostnameVerifierOptions
Default
DEFAULT
Defined by
SpnegoLdapProperties
cas.authn.spnego.ldap.idle-timeRemoves connections from the pool based on how long they have been idle in the available queue.
PT10M
Duration

Removes connections from the pool based on how long they have been idle in the available queue. Prunes connections that have been idle for more than the indicated amount.

Type
String
Default
PT10M
Defined by
SpnegoLdapProperties
cas.authn.spnego.ldap.keystorePath to the keystore used for SSL connections.
no default
SpEL

Path to the keystore used for SSL connections. Typically contains SSL certificates for the LDAP server.

Type
String
Default
none
Defined by
SpnegoLdapProperties
Supports
Spring Expression Language
cas.authn.spnego.ldap.keystore-passwordKeystore password.
no default
SpEL

Keystore password.

Type
String
Default
none
Defined by
SpnegoLdapProperties
Supports
Spring Expression Language
cas.authn.spnego.ldap.keystore-typeThe type of keystore.
no default

The type of keystore. PKCS12 or JKS. If left blank, defaults to the default keystore type indicated by the underlying Java platform.

Type
String
Default
none
Defined by
SpnegoLdapProperties
cas.authn.spnego.ldap.max-pool-sizeMaximum LDAP connection pool size which the pool can use to grow.
10

Maximum LDAP connection pool size which the pool can use to grow.

Type
Integer
Default
10
Defined by
SpnegoLdapProperties
cas.authn.spnego.ldap.min-pool-sizeMinimum LDAP connection pool size.
3

Minimum LDAP connection pool size. Size the pool should be initialized to and pruned to

Type
Integer
Default
3
Defined by
SpnegoLdapProperties
cas.authn.spnego.ldap.nameName of the LDAP handler.
no default

Name of the LDAP handler.

Type
String
Default
none
Defined by
SpnegoLdapProperties
cas.authn.spnego.ldap.page-sizeRequest that the server return results in batches of a specific size.
0

Request that the server return results in batches of a specific size. See RFC 2696. This control is often used to work around server result size limits. A negative/zero value disables paged requests.

Type
Integer
Default
0
Defined by
SpnegoLdapProperties
cas.authn.spnego.ldap.pool-passivatorYou may receive unexpected LDAP failures, when CAS is configured to authenticate using DIRECT or AUTHENTICATED types and LDAP is locked down to not allow anonymous binds/searches.
BIND
You may receive unexpected LDAP failures, when CAS is configured to authenticate using DIRECT or AUTHENTICATED types and LDAP is locked down to not allow anonymous binds/searches. Every second attempt with a given LDAP connection from the pool would fail if it was on the same connection as a failed login attempt, and the regular connection validator would similarly fail. When a connection is returned back to a pool, it still may contain the principal and credentials from the previous attempt. Before the next bind attempt using that connection, the validator tries to validate the connection again but fails because it’s no longer trying with the configured bind credentials but with whatever user DN was used in the previous step. Given the validation failure, the connection is closed and CAS would deny access by default. Passivators attempt to reconnect to LDAP with the configured bind credentials, effectively resetting the connection to what it should be after each bind request. Furthermore if you are seeing errors in the logs that resemble a 'Operation exception encountered, reopening connection' type of message, this usually is an indication that the connection pool’s validation timeout established and created by CAS is greater than the timeout configured in the LDAP server, or more likely, in the load balancer in front of the LDAP servers. You can adjust the LDAP server session’s timeout for connections, or you can teach CAS to use a validity period that is equal or less than the LDAP server session’s timeout. Accepted values are:
  • NONE: No passivation takes place.
  • BIND: The default behavior which passivates a connection by performing a bind operation on it. This option requires the availability of bind credentials when establishing connections to LDAP.
Type
String
Default
BIND
Defined by
SpnegoLdapProperties
cas.authn.spnego.ldap.prune-periodRemoves connections from the pool based on how long they have been idle in the available queue.
PT2H
Duration

Removes connections from the pool based on how long they have been idle in the available queue. Run the pruning process at the indicated interval.

Type
String
Default
PT2H
Defined by
SpnegoLdapProperties
cas.authn.spnego.ldap.response-timeoutDuration of time to wait for responses.
PT5S
Duration

Duration of time to wait for responses.

Type
String
Default
PT5S
Defined by
SpnegoLdapProperties
cas.authn.spnego.ldap.sasl-authorization-idSASL authorization id.
no default

SASL authorization id.

Type
String
Default
none
Defined by
SpnegoLdapProperties
cas.authn.spnego.ldap.sasl-mechanismThe SASL mechanism.
no default

The SASL mechanism.

Type
String
Default
none
Defined by
SpnegoLdapProperties
cas.authn.spnego.ldap.sasl-mutual-authWhether SASL mutual authentication is enabled.
no default

Whether SASL mutual authentication is enabled.

Type
Boolean
Default
none
Defined by
SpnegoLdapProperties
cas.authn.spnego.ldap.sasl-quality-of-protectionSASL quality of protected.
no default

SASL quality of protected.

Type
String
Default
none
Defined by
SpnegoLdapProperties
cas.authn.spnego.ldap.sasl-realmThe SASL realm.
no default

The SASL realm.

Type
String
Default
none
Defined by
SpnegoLdapProperties
cas.authn.spnego.ldap.sasl-security-strengthSASL security strength.
no default

SASL security strength.

Type
String
Default
none
Defined by
SpnegoLdapProperties
cas.authn.spnego.ldap.search-entry-handlersSearch handlers.
no default

Search handlers.

Type
List<LdapSearchEntryHandlersProperties>
Default
none
Defined by
SpnegoLdapProperties
cas.authn.spnego.ldap.search-entry-handlers[0].case-change.attribute-name-case-changeThe Attribute name case change.
no default

The Attribute name case change.

Type
String
Default
none
Defined by
CaseChangeSearchEntryHandlersProperties
cas.authn.spnego.ldap.search-entry-handlers[0].case-change.attribute-namesThe Attribute names.
no default

The Attribute names.

Type
List<String>
Default
none
Defined by
CaseChangeSearchEntryHandlersProperties
cas.authn.spnego.ldap.search-entry-handlers[0].case-change.attribute-value-case-changeThe Attribute value case change.
no default

The Attribute value case change.

Type
String
Default
none
Defined by
CaseChangeSearchEntryHandlersProperties
cas.authn.spnego.ldap.search-entry-handlers[0].case-change.dn-case-changeThe Dn case change.
no default

The Dn case change.

Type
String
Default
none
Defined by
CaseChangeSearchEntryHandlersProperties
cas.authn.spnego.ldap.search-entry-handlers[0].dn-attribute.add-if-existsThe Add if exists.
no default

The Add if exists.

Type
boolean
Default
none
Defined by
DnAttributeSearchEntryHandlersProperties
cas.authn.spnego.ldap.search-entry-handlers[0].dn-attribute.dn-attribute-nameThe Dn attribute name.
entryDN

The Dn attribute name.

Type
String
Default
entryDN
Defined by
DnAttributeSearchEntryHandlersProperties
cas.authn.spnego.ldap.search-entry-handlers[0].merge-attribute.attribute-namesThe Attribute names.
no default

The Attribute names.

Type
List<String>
Default
none
Defined by
MergeAttributesSearchEntryHandlersProperties
cas.authn.spnego.ldap.search-entry-handlers[0].merge-attribute.merge-attribute-nameThe Merge attribute name.
no default

The Merge attribute name.

Type
String
Default
none
Defined by
MergeAttributesSearchEntryHandlersProperties
cas.authn.spnego.ldap.search-entry-handlers[0].primary-group-id.base-dnThe Base dn.
no default

The Base dn.

Type
String
Default
none
Defined by
PrimaryGroupIdSearchEntryHandlersProperties
cas.authn.spnego.ldap.search-entry-handlers[0].primary-group-id.group-filterThe Group filter.
(&(objectClass=group)(objectSid={0}))

The Group filter.

Type
String
Default
(&(objectClass=group)(objectSid={0}))
Defined by
PrimaryGroupIdSearchEntryHandlersProperties
cas.authn.spnego.ldap.search-entry-handlers[0].recursive.merge-attributesThe Merge attributes.
no default

The Merge attributes.

Type
List<String>
Default
none
Defined by
RecursiveSearchEntryHandlersProperties
cas.authn.spnego.ldap.search-entry-handlers[0].recursive.search-attributeThe Search attribute.
no default

The Search attribute.

Type
String
Default
none
Defined by
RecursiveSearchEntryHandlersProperties
cas.authn.spnego.ldap.search-entry-handlers[0].search-referral.limitThe default referral limit.
10

The default referral limit.

Type
int
Default
10
Defined by
FollowReferralSearchEntryHandlersProperties
cas.authn.spnego.ldap.search-entry-handlers[0].search-result.limitThe default referral limit.
10

The default referral limit.

Type
int
Default
10
Defined by
FollowResultSearchEntryHandlersProperties
cas.authn.spnego.ldap.search-entry-handlers[0].typeThe type of search entry handler to choose.
no default
The type of search entry handler to choose. Available values are as follows:
  • FOLLOW_SEARCH_REFERRAL: Provides handling of an ldap referral for search operations.
  • FOLLOW_SEARCH_RESULT_REFERENCE: Provides handling of an ldap continuation reference for search operations.
  • ACTIVE_DIRECTORY: Process the entry results fetched from active directory and check for account status controls for disabled/expired accounts, etc.
  • OBJECT_GUID: Object guid search entry handler. Handles the objectGUID attribute fetching and conversion.
  • OBJECT_SID: Object sid search entry handler. Handles the objectSid attribute fetching and conversion.
  • CASE_CHANGE: Case change search entry handler. Provides the ability to modify the case of search entry DNs, attribute names, and attribute values.
  • DN_ATTRIBUTE_ENTRY: DN attribute entry handler. Adds the entry DN as an attribute to the result set. Provides a client side implementation of RFC 5020.
  • MERGE: Merge search entry handler. Merges the values of one or more attributes into a single attribute.
  • PRIMARY_GROUP: Primary group search handler. Constructs the primary group SID and then searches for that group and puts it's DN in the memberOf attribute of the original search entry.
  • RANGE_ENTRY: Range entry search handler. Rewrites attributes returned from Active Directory to include all values by performing additional searches.
  • RECURSIVE_ENTRY: Recursive entry search handler. This recursively searches based on a supplied attribute and merges those results into the original entry.
  • MERGE_ENTRIES: Merge entries handler. Merges the values of one or more attributes in all entries into a single attribute. The merged attribute may or may not already exist on the entry. If it does exist it's existing values will remain intact.
Type
LdapSearchEntryHandlersProperties.SearchEntryHandlerTypes
Default
none
Defined by
LdapSearchEntryHandlersProperties
cas.authn.spnego.ldap.subtree-searchWhether subtree searching is allowed.
true

Whether subtree searching is allowed.

Type
Boolean
Default
true
Defined by
SpnegoLdapProperties
cas.authn.spnego.ldap.trust-certificatesPath of the trust certificates to use for the SSL connection.
no default

Path of the trust certificates to use for the SSL connection. Ignores keystore-related settings when activated and used.

Type
String
Default
none
Defined by
SpnegoLdapProperties
cas.authn.spnego.ldap.trust-managerTrust Manager options.
no default
Trust Manager options. Trust managers are responsible for managing the trust material that is used when making LDAP trust decisions, and for deciding whether credentials presented by a peer should be accepted. Accepted values are:
  • DEFAULT: Enable and force the default JVM trust managers.
  • ANY: Trust any client or server.
Type
String
Default
none
Defined by
SpnegoLdapProperties
cas.authn.spnego.ldap.trust-storePath to the keystore used to determine which certificates or certificate authorities should be trusted.
no default
SpEL

Path to the keystore used to determine which certificates or certificate authorities should be trusted. Used when connecting to an LDAP server via LDAPS or startTLS connection. If left blank, the default truststore for the Java runtime is used.

Type
String
Default
none
Defined by
SpnegoLdapProperties
Supports
Spring Expression Language
cas.authn.spnego.ldap.trust-store-passwordPassword needed to open the truststore.
no default
SpEL

Password needed to open the truststore.

Type
String
Default
none
Defined by
SpnegoLdapProperties
Supports
Spring Expression Language
cas.authn.spnego.ldap.trust-store-typeThe type of trust keystore that determines which certificates or certificate authorities are trusted.
no default

The type of trust keystore that determines which certificates or certificate authorities are trusted. Types depend on underlying java platform, typically PKCS12 or JKS. If left blank, defaults to the default keystore type indicated by the underlying Java platform.

Type
String
Default
none
Defined by
SpnegoLdapProperties
cas.authn.spnego.ldap.use-start-tlsWhether TLS should be used and enabled when establishing the connection.
false

Whether TLS should be used and enabled when establishing the connection.

Type
Boolean
Default
false
Defined by
SpnegoLdapProperties
cas.authn.spnego.ldap.validate-on-checkoutWhether connections should be validated when loaned out from the pool.
true

Whether connections should be validated when loaned out from the pool.

Type
Boolean
Default
true
Defined by
SpnegoLdapProperties
cas.authn.spnego.ldap.validate-periodPeriod at which pool should be validated.
PT5M
Duration

Period at which pool should be validated.

Type
String
Default
PT5M
Defined by
SpnegoLdapProperties
cas.authn.spnego.ldap.validate-periodicallyWhether connections should be validated periodically when the pool is idle.
true

Whether connections should be validated periodically when the pool is idle.

Type
Boolean
Default
true
Defined by
SpnegoLdapProperties
cas.authn.spnego.ldap.validate-timeoutPeriod at which validation operations may time out.
PT5S
Duration

Period at which validation operations may time out.

Type
String
Default
PT5S
Defined by
SpnegoLdapProperties
cas.authn.spnego.ldap.validator.attribute-nameAttribute name to use for the compare validator.
objectClass

Attribute name to use for the compare validator.

Type
String
Default
objectClass
Defined by
LdapValidatorProperties
cas.authn.spnego.ldap.validator.attribute-valueAttribute values to use for the compare validator.
top

Attribute values to use for the compare validator.

Type
String
Default
top
Defined by
LdapValidatorProperties
cas.authn.spnego.ldap.validator.base-dnBase DN to use for the search request of the search validator.
no default

Base DN to use for the search request of the search validator.

Type
String
Default
none
Defined by
LdapValidatorProperties
cas.authn.spnego.ldap.validator.dnDN to compare to use for the compare validator.
no default

DN to compare to use for the compare validator.

Type
String
Default
none
Defined by
LdapValidatorProperties
cas.authn.spnego.ldap.validator.scopeSearch scope to use for the search request of the search validator.
OBJECT

Search scope to use for the search request of the search validator.

Type
String
Default
OBJECT
Defined by
LdapValidatorProperties
cas.authn.spnego.ldap.validator.search-filterSearch filter to use for the search request of the search validator.
(objectClass=*)

Search filter to use for the search request of the search validator.

Type
String
Default
(objectClass=*)
Defined by
LdapValidatorProperties
cas.authn.spnego.ldap.validator.typeDetermine the LDAP validator type.
search

Determine the LDAP validator type.

The following LDAP validators can be used to test connection health status:
  • search: Validates a connection is healthy by performing a search operation. Validation is considered successful if the search result size is greater than zero.
  • none: No validation takes place.
  • compare: Validates a connection is healthy by performing a compare operation.
Type
String
Default
search
Defined by
LdapValidatorProperties
cas.authn.spnego.mixed-mode-authenticationIf true, does not terminate authentication and allows CAS to resume and fallback to normal authentication means such as uid/psw via the login page.
false

If true, does not terminate authentication and allows CAS to resume and fallback to normal authentication means such as uid/psw via the login page. If disallowed, considers spnego authentication to be final in the event of failures.

Type
Boolean
Default
false
Defined by
SpnegoProperties
cas.authn.spnego.nameName of the authentication handler.
no default

Name of the authentication handler.

Type
String
Default
none
Defined by
SpnegoProperties
cas.authn.spnego.ntlm-allowedAllows authentication if spnego credential is marked as NTLM.
true

Allows authentication if spnego credential is marked as NTLM.

Type
Boolean
Default
true
Defined by
SpnegoProperties
cas.authn.spnego.orderThe order of the authentication handler in the chain.
no default

The order of the authentication handler in the chain.

Type
Integer
Default
none
Defined by
SpnegoProperties
cas.authn.spnego.pool-sizeThe size of the pool used to validate SPNEGO tokens.
10

The size of the pool used to validate SPNEGO tokens. A pool is used to provider better performance than what was previously offered by the simple Lombok Synchronized annotation.

Type
Integer
Default
10
Defined by
SpnegoProperties
cas.authn.spnego.pool-timeoutThe timeout of the pool used to validate SPNEGO tokens.
PT2S
Duration

The timeout of the pool used to validate SPNEGO tokens.

Type
String
Default
PT2S
Defined by
SpnegoProperties
cas.authn.spnego.principal-transformation.blocking-patternA regular expression that will be used against the username to match for blocking/forbidden values.
no default
SpEL

A regular expression that will be used against the username to match for blocking/forbidden values. If a match is found, an exception will be thrown and principal transformation will fail.

Type
String
Default
none
Defined by
PrincipalTransformationProperties
Supports
Spring Expression Language
cas.authn.spnego.principal-transformation.case-conversionIndicate whether the principal identifier should be transformed into upper-case, lower-case, etc.
NONE
Indicate whether the principal identifier should be transformed into upper-case, lower-case, etc. Available values are as follows:
  • NONE: No conversion.
  • LOWERCASE: Lowercase conversion.
  • UPPERCASE: Uppercase conversion.
Type
PrincipalTransformationProperties.CaseConversion
Default
NONE
Defined by
PrincipalTransformationProperties
cas.authn.spnego.principal-transformation.patternA regular expression that will be used against the provided username for username extractions.
no default
SpEL

A regular expression that will be used against the provided username for username extractions. On a successful match, the first matched group in the pattern will be used as the extracted username.

Type
String
Default
none
Defined by
PrincipalTransformationProperties
Supports
Spring Expression Language
cas.authn.spnego.principal-transformation.prefixPrefix to add to the principal id prior to authentication.
no default
SpEL

Prefix to add to the principal id prior to authentication.

Type
String
Default
none
Defined by
PrincipalTransformationProperties
Supports
Spring Expression Language
cas.authn.spnego.principal-transformation.suffixSuffix to add to the principal id prior to authentication.
no default
SpEL

Suffix to add to the principal id prior to authentication.

Type
String
Default
none
Defined by
PrincipalTransformationProperties
Supports
Spring Expression Language
cas.authn.spnego.principal-with-domain-nameIf specified, will create the principal by this name on successful authentication.
false

If specified, will create the principal by this name on successful authentication.

Type
Boolean
Default
false
Defined by
SpnegoProperties
cas.authn.spnego.principal.active-attribute-repository-idsActivated attribute repository identifiers that should be used for fetching attributes if attribute resolution is enabled.
*

Activated attribute repository identifiers that should be used for fetching attributes if attribute resolution is enabled. The list here may include identifiers separated by comma.

Type
String
Default
*
Defined by
PersonDirectoryPrincipalResolverProperties
cas.authn.spnego.principal.attribute-repository-selectionControl the behavior of the attribute repository selection by authentication method or handler.
no default

Control the behavior of the attribute repository selection by authentication method or handler. The map here is keyed by the authentication handler name, and the value is the attribute repository identifiers separated by comma. When the authentication handler is executed, the attribute repositories assigned to this handler will be selected to fetch attributes. Note that the resolution engine will always favor attribute repositories assigned to the service definition, if any and as part of its authentication policy, over this global setting.

Type
Map<String,String>
Default
none
Defined by
PersonDirectoryPrincipalResolverProperties
cas.authn.spnego.principal.attribute-resolution-enabledWhether attribute repositories should be contacted to fetch person attributes.
undefined
Whether attribute repositories should be contacted to fetch person attributes. Defaults to true if not set. Available values are as follows:
  • TRUE: Constant to represent the true state.
  • FALSE: Constant to represent the false state.
  • UNDEFINED: Constant to represent the undefined state.
Type
TriStateBoolean
Default
undefined
Defined by
PersonDirectoryPrincipalResolverProperties
cas.authn.spnego.principal.principal-attributeAttribute name to use to indicate the identifier of the principal constructed.
no default

Attribute name to use to indicate the identifier of the principal constructed. If the attribute is blank or has no values, the default principal id will be used determined by the underlying authentication engine. The principal id attribute usually is removed from the collection of attributes collected, though this behavior depends on the schematics of the underlying authentication strategy.

Type
String
Default
none
Defined by
PersonDirectoryPrincipalResolverProperties
cas.authn.spnego.principal.principal-resolution-conflict-strategyIn the event that the principal resolution engine resolves more than one principal, (especially if such principals in the chain have different identifiers), this setting determines strategy by which the principal id w...
last

In the event that the principal resolution engine resolves more than one principal, (especially if such principals in the chain have different identifiers), this setting determines strategy by which the principal id would be chosen from the chain. Accepted values are: last, first.

Type
String
Default
last
Defined by
PersonDirectoryPrincipalResolverProperties
cas.authn.spnego.principal.principal-resolution-failure-fatalWhen true, throws an error back indicating that principal resolution has failed and no principal can be found based on the authentication requirements.
undefined
When true, throws an error back indicating that principal resolution has failed and no principal can be found based on the authentication requirements. Otherwise, logs the condition as an error without raising a catastrophic error. Available values are as follows:
  • TRUE: Constant to represent the true state.
  • FALSE: Constant to represent the false state.
  • UNDEFINED: Constant to represent the undefined state.
Type
TriStateBoolean
Default
undefined
Defined by
PersonDirectoryPrincipalResolverProperties
cas.authn.spnego.principal.principal-transformation.blocking-patternA regular expression that will be used against the username to match for blocking/forbidden values.
no default
SpEL

A regular expression that will be used against the username to match for blocking/forbidden values. If a match is found, an exception will be thrown and principal transformation will fail.

Type
String
Default
none
Defined by
PrincipalTransformationProperties
Supports
Spring Expression Language
cas.authn.spnego.principal.principal-transformation.case-conversionIndicate whether the principal identifier should be transformed into upper-case, lower-case, etc.
NONE
Indicate whether the principal identifier should be transformed into upper-case, lower-case, etc. Available values are as follows:
  • NONE: No conversion.
  • LOWERCASE: Lowercase conversion.
  • UPPERCASE: Uppercase conversion.
Type
PrincipalTransformationProperties.CaseConversion
Default
NONE
Defined by
PrincipalTransformationProperties
cas.authn.spnego.principal.principal-transformation.patternA regular expression that will be used against the provided username for username extractions.
no default
SpEL

A regular expression that will be used against the provided username for username extractions. On a successful match, the first matched group in the pattern will be used as the extracted username.

Type
String
Default
none
Defined by
PrincipalTransformationProperties
Supports
Spring Expression Language
cas.authn.spnego.principal.principal-transformation.prefixPrefix to add to the principal id prior to authentication.
no default
SpEL

Prefix to add to the principal id prior to authentication.

Type
String
Default
none
Defined by
PrincipalTransformationProperties
Supports
Spring Expression Language
cas.authn.spnego.principal.principal-transformation.suffixSuffix to add to the principal id prior to authentication.
no default
SpEL

Suffix to add to the principal id prior to authentication.

Type
String
Default
none
Defined by
PrincipalTransformationProperties
Supports
Spring Expression Language
cas.authn.spnego.principal.return-nullReturn a null principal object if no attributes can be found for the principal.
undefined
Return a null principal object if no attributes can be found for the principal. Available values are as follows:
  • TRUE: Constant to represent the true state.
  • FALSE: Constant to represent the false state.
  • UNDEFINED: Constant to represent the undefined state.
Type
TriStateBoolean
Default
undefined
Defined by
PersonDirectoryPrincipalResolverProperties
cas.authn.spnego.principal.use-existing-principal-idUses an existing principal id that may have already been established in order to run person directory queries.
undefined
Uses an existing principal id that may have already been established in order to run person directory queries. This is generally useful in situations where authentication is delegated to an external identity provider and a principal is first established to then query an attribute source. Available values are as follows:
  • TRUE: Constant to represent the true state.
  • FALSE: Constant to represent the false state.
  • UNDEFINED: Constant to represent the undefined state.
Type
TriStateBoolean
Default
undefined
Defined by
PersonDirectoryPrincipalResolverProperties
cas.authn.spnego.propertiesIndividual authentication settings for spengo that are grouped and fed to the spnego authentication object to form a collection.
no default

Individual authentication settings for spengo that are grouped and fed to the spnego authentication object to form a collection.

Type
List<SpnegoAuthenticationProperties>
Default
none
Defined by
SpnegoProperties
cas.authn.spnego.properties[0].cache-policyJcifs Netbios cache policy.
600

Jcifs Netbios cache policy.

Type
long
Default
600
Defined by
SpnegoAuthenticationProperties
cas.authn.spnego.properties[0].jcifs-domainThe Jcifs domain.
no default

The Jcifs domain.

Type
String
Default
none
Defined by
SpnegoAuthenticationProperties
cas.authn.spnego.properties[0].jcifs-domain-controllerThe Jcifs domain controller.
no default

The Jcifs domain controller.

Type
String
Default
none
Defined by
SpnegoAuthenticationProperties
cas.authn.spnego.properties[0].jcifs-netbios-winsThe Jcifs netbios wins.
no default

The Jcifs netbios wins.

Type
String
Default
none
Defined by
SpnegoAuthenticationProperties
cas.authn.spnego.properties[0].jcifs-passwordThe Jcifs password.
no default

The Jcifs password.

Type
String
Default
none
Defined by
SpnegoAuthenticationProperties
cas.authn.spnego.properties[0].jcifs-service-passwordThe Jcifs service password.
no default

The Jcifs service password.

Type
String
Default
none
Defined by
SpnegoAuthenticationProperties
cas.authn.spnego.properties[0].jcifs-usernameThe Jcifs username.
no default

The Jcifs username.

Type
String
Default
none
Defined by
SpnegoAuthenticationProperties
cas.authn.spnego.properties[0].timeoutSpnego JCIFS timeout.
PT5M
Duration

Spnego JCIFS timeout.

Type
String
Default
PT5M
Defined by
SpnegoAuthenticationProperties
cas.authn.spnego.send401-on-authentication-failureIf the authenticated principal cannot be determined from the spegno credential, will set the http status code to 401.
true

If the authenticated principal cannot be determined from the spegno credential, will set the http status code to 401.

Type
Boolean
Default
true
Defined by
SpnegoProperties
cas.authn.spnego.spnego-attribute-nameIn case LDAP is used to validate clients, this is the attribute that indicates the host.
distinguishedName

In case LDAP is used to validate clients, this is the attribute that indicates the host.

Type
String
Default
distinguishedName
Defined by
SpnegoProperties
cas.authn.spnego.supported-browsersBegins negotiating spnego if the user-agent is one of the supported browsers.
MSIE,Trident,Firefox,AppleWebKit

Begins negotiating spnego if the user-agent is one of the supported browsers.

Type
String
Default
MSIE,Trident,Firefox,AppleWebKit
Defined by
SpnegoProperties
cas.authn.spnego.system.kerberos-confThe Kerberos conf.
no default

The Kerberos conf. As with all Kerberos installations, a Kerberos Key Distribution Center (KDC) is required. It needs to contain the user name and password you will use to be authenticated to Kerberos. As with most Kerberos installations, a Kerberos configuration file krb5.conf is consulted to determine such things as the default realm and KDC. Typically, the default realm and the KDC for that realm are indicated in the Kerberos krb5.conf configuration file. The path to the configuration file must typically be defined as an absolute path.

Type
String
Default
none
Defined by
SpnegoSystemProperties
cas.authn.spnego.system.kerberos-debugThe Kerberos debug.
no default

The Kerberos debug.

Type
String
Default
none
Defined by
SpnegoSystemProperties
cas.authn.spnego.system.kerberos-kdcThe Kerberos kdc.
172.10.1.10

The Kerberos kdc.

Type
String
Default
172.10.1.10
Defined by
SpnegoSystemProperties
cas.authn.spnego.system.kerberos-realmThe Kerberos realm.
EXAMPLE.COM

The Kerberos realm.

Type
String
Default
EXAMPLE.COM
Defined by
SpnegoSystemProperties
cas.authn.spnego.system.login-confThe Login conf.Absolute path to the jaas login configuration file.
no default

The Login conf.Absolute path to the jaas login configuration file. This should define the spnego authentication details. Make sure you have at least specified the JCIFS Service Principal defined.

Type
String
Default
none
Defined by
SpnegoSystemProperties
cas.authn.spnego.system.use-subject-creds-onlyThe Use subject creds only.
false

The Use subject creds only.

Type
Boolean
Default
false
Defined by
SpnegoSystemProperties
cas.authn.spnego.webflow.enabledWhether webflow auto-configuration should be enabled.
true

Whether webflow auto-configuration should be enabled.

Type
Boolean
Default
true
Defined by
WebflowAutoConfigurationProperties
cas.authn.spnego.webflow.orderThe order in which the webflow is configured.
0

The order in which the webflow is configured.

Type
Integer
Default
0
Defined by
WebflowAutoConfigurationProperties

Required settings may be needed to activate or affect the feature; review them even when they have a default. Optional settings only need to be set to change a default or to turn on the behavior they control. Third party settings belong to libraries such as Spring Boot that CAS builds on; their own documentation may have more detail.

Groovy scripting

CAS takes advantage of Apache Groovy in forms of either embedded or external scripts that allow one to, by default, dynamically build constructs, attributes, access strategies and a lot more. To activate the functionality described here, you may need to prepare CAS to support and integrate with Apache Groovy.

Please review this guide to configure your build.

LDAP & Active Directory

LDAP Scriptable Search Filter

LDAP search filters can point to an external Groovy script to dynamically construct the final filter template.

The script itself may be designed as:



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import org.ldaptive.*
import org.springframework.context.*

def run(Object[] args) {
    def (filter,parameters,applicationContext,logger) = args

    logger.info("Configuring LDAP filter")
    filter.setFilter("uid=something")
}

The following parameters are passed to the script:

Parameter Description
filter FilterTemplate to be updated by the script and used for the LDAP query.
parameters Map of query parameters which may be used to construct the final filter.
applicationContext Reference to the Spring ApplicationContext reference.
logger The object responsible for issuing log messages such as logger.info(...).

To prepare CAS to support and integrate with Apache Groovy, please review this guide.

Principal transformation

Authentication handlers that generally deal with username-password credentials can be configured to transform the user id prior to executing the authentication sequence. Each authentication strategy in CAS provides settings to properly transform the principal. Refer to the relevant settings for the authentication strategy at hand to learn more.

Authentication handlers as part of principal transformation may also be provided a path to a Groovy script to transform the provided username. The outline of the script may take on the following form:



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String run(final Object... args) {
    def (providedUsername,logger) = args
    return providedUsername.concat("SomethingElse")
}

To prepare CAS to support and integrate with Apache Groovy, please review this guide.

Notes on configuration

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.

: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.

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, especially 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.

You may provide a JAAS login.conf file:



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jcifs.spnego.initiate {
   com.sun.security.auth.module.Krb5LoginModule \
    required storeKey=true useKeyTab=true keyTab="/home/cas/kerberos/myspnaccount.keytab";
};
jcifs.spnego.accept {
   com.sun.security.auth.module.Krb5LoginModule \
    required storeKey=true useKeyTab=true keyTab="/home/cas/kerberos/myspnaccount.keytab";
};

Client Selection Strategy

CAS provides a set of components that attempt to activate the SPNEGO flow conditionally, in case deployers need a configurable way to decide whether SPNEGO should be applied to the current authentication/browser request. The state that is available to the webflow is evaluateClientRequest which will attempt to start SPNEGO authentication or resume normally, depending on the client action strategy chosen below.

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

cas.authn.spnego.alternative-remote-host-attributeAlternative header name to use in order to find the host address.
alternateRemoteHeader

Alternative header name to use in order to find the host address.

Type
String
Default
alternateRemoteHeader
Defined by
SpnegoProperties
cas.authn.spnego.dns-timeoutWhen validating clients, specifies the DNS timeout used to look up an address.
PT2S
Duration

When validating clients, specifies the DNS timeout used to look up an address.

Type
String
Default
PT2S
Defined by
SpnegoProperties
cas.authn.spnego.host-name-client-action-strategyThe bean id of a webflow action whose job is to evaluate the client host to see if the request is authorized for spnego.
hostnameSpnegoClientAction

The bean id of a webflow action whose job is to evaluate the client host to see if the request is authorized for spnego. Supported strategies include hostnameSpnegoClientAction where CAS checks to see if the request’s remote hostname matches a predefine pattern. and ldapSpnegoClientAction where CAS checks an LDAP instance for the remote hostname, to locate a pre-defined attribute whose mere existence would allow the webflow to resume to SPNEGO.

Type
String
Default
hostnameSpnegoClientAction
Defined by
SpnegoProperties
cas.authn.spnego.host-name-pattern-stringA regex pattern that indicates whether the client host name is allowed for spnego.
.+
Regex

A regex pattern that indicates whether the client host name is allowed for spnego.

Type
String
Default
.+
Defined by
SpnegoProperties
cas.authn.spnego.ips-to-check-patternA regex pattern that indicates whether the client IP is allowed for spnego.
127.+
Regex

A regex pattern that indicates whether the client IP is allowed for spnego.

Type
String
Default
127.+
Defined by
SpnegoProperties

Required settings may be needed to activate or affect the feature; review them even when they have a default. Optional settings only need to be set to change a default or to turn on the behavior they control. Third party settings belong to libraries such as Spring Boot that CAS builds on; their own documentation may have more detail.

Notes on configuration

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.

: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.

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, especially 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.

By Remote IP

Checks to see if the request’s remote ip address matches a predefine pattern.

By Hostname

Checks to see if the request’s remote hostname matches a predefine pattern.

By LDAP Attribute

Checks an LDAP instance for the remote hostname, to locate a pre-defined attribute whose mere existence would allow the webflow to resume to SPNEGO.

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

cas.authn.spnego.ldap.base-dnBase DN to use.
no default
Required

Base DN to use. There may be scenarios where different parts of a single LDAP tree could be considered as base-dns. Rather than duplicating the LDAP configuration block for each individual base-dn, each entry can be specified and joined together using a special delimiter character. The user DN is retrieved using the combination of all base-dn and DN resolvers in the order defined. DN resolution should fail if multiple DNs are found. Otherwise the first DN found is returned. Usual syntax is: subtreeA,dc=example,dc=net|subtreeC,dc=example,dc=net.

Type
String
Default
none
Defined by
SpnegoLdapProperties
cas.authn.spnego.ldap.bind-credentialThe bind credential to use when connecting to LDAP.
no default
Required

The bind credential to use when connecting to LDAP.

Type
String
Default
none
Defined by
SpnegoLdapProperties
cas.authn.spnego.ldap.bind-dnThe bind DN to use when connecting to LDAP.
no default
Required
The bind DN to use when connecting to LDAP. LDAP connection configuration injected into the LDAP connection pool can be initialized with the following parameters:
  • bindDn/bindCredential provided - Use the provided credentials to bind when initializing connections.
  • bindDn/bindCredential set to * - Use a fast-bind strategy to initialize the pool.
  • bindDn/bindCredential set to blank - Skip connection initializing; perform operations anonymously.
  • SASL mechanism provided - Use the given SASL mechanism to bind when initializing connections.
Type
String
Default
none
Defined by
SpnegoLdapProperties
cas.authn.spnego.ldap.ldap-urlThe LDAP url to the server.
no default
Required

The LDAP url to the server. More than one may be specified, separated by space and/or comma.

Type
String
Default
none
Defined by
SpnegoLdapProperties
cas.authn.spnego.ldap.search-filterUser filter to use for searching.
no default
Required

User filter to use for searching. Syntax is cn={user} or cn={0}.

You may also provide an external groovy script in the syntax of file:/path/to/GroovyScript.groovy to fully build the final filter template dynamically.

Type
String
Default
none
Defined by
SpnegoLdapProperties
cas.authn.spnego.ldap.allow-multiple-dnsWhether search/query results are allowed to match on multiple DNs, or whether a single unique DN is expected for the result.
false

Whether search/query results are allowed to match on multiple DNs, or whether a single unique DN is expected for the result.

Type
Boolean
Default
false
Defined by
SpnegoLdapProperties
cas.authn.spnego.ldap.allow-multiple-entriesSet if multiple Entries are allowed.
false

Set if multiple Entries are allowed.

Type
Boolean
Default
false
Defined by
SpnegoLdapProperties
cas.authn.spnego.ldap.binary-attributesIndicate the collection of attributes that are to be tagged and processed as binary attributes by the underlying search resolver.
no default

Indicate the collection of attributes that are to be tagged and processed as binary attributes by the underlying search resolver.

Type
List<String>
Default
none
Defined by
SpnegoLdapProperties
cas.authn.spnego.ldap.block-wait-timeThe length of time the pool will block.
PT3S
Duration

The length of time the pool will block. By default the pool will block indefinitely and there is no guarantee that waiting threads will be serviced in the order in which they made their request. This option should be used with a blocking connection pool when you need to control the exact number of connections that can be created

Type
String
Default
PT3S
Defined by
SpnegoLdapProperties
cas.authn.spnego.ldap.connect-timeoutSets the maximum amount of time that connects will block.
PT5S
Duration

Sets the maximum amount of time that connects will block.

Type
String
Default
PT5S
Defined by
SpnegoLdapProperties
cas.authn.spnego.ldap.connection-strategyIf multiple URLs are provided as the ldapURL this describes how each URL will be processed.
no default
If multiple URLs are provided as the ldapURL this describes how each URL will be processed.
  • ACTIVE_PASSIVE First LDAP will be used for every request unless it fails and then the next shall be used.
  • ROUND_ROBIN For each new connection the next url in the list will be used.
  • RANDOM For each new connection a random LDAP url will be selected.
  • DNS_SRV LDAP urls based on DNS SRV records of the configured/given LDAP url will be used.
Type
String
Default
none
Defined by
SpnegoLdapProperties
cas.authn.spnego.ldap.disable-poolingWhether to use a pooled connection factory in components.
false

Whether to use a pooled connection factory in components.

Type
Boolean
Default
false
Defined by
SpnegoLdapProperties
cas.authn.spnego.ldap.fail-fastAttempt to populate the connection pool early on startup and fail quickly if something goes wrong.
true

Attempt to populate the connection pool early on startup and fail quickly if something goes wrong.

Type
Boolean
Default
true
Defined by
SpnegoLdapProperties
cas.authn.spnego.ldap.follow-referralsSet if search referrals should be followed.
true

Set if search referrals should be followed.

Type
Boolean
Default
true
Defined by
SpnegoLdapProperties
cas.authn.spnego.ldap.hostname-verifierHostname verification options.
DEFAULT
Hostname verification options. Available values are as follows:
  • DEFAULT: Default option, forcing verification.
  • ANY: Skip hostname verification and allow all.
Type
AbstractLdapProperties.LdapHostnameVerifierOptions
Default
DEFAULT
Defined by
SpnegoLdapProperties
cas.authn.spnego.ldap.idle-timeRemoves connections from the pool based on how long they have been idle in the available queue.
PT10M
Duration

Removes connections from the pool based on how long they have been idle in the available queue. Prunes connections that have been idle for more than the indicated amount.

Type
String
Default
PT10M
Defined by
SpnegoLdapProperties
cas.authn.spnego.ldap.keystorePath to the keystore used for SSL connections.
no default
SpEL

Path to the keystore used for SSL connections. Typically contains SSL certificates for the LDAP server.

Type
String
Default
none
Defined by
SpnegoLdapProperties
Supports
Spring Expression Language
cas.authn.spnego.ldap.keystore-passwordKeystore password.
no default
SpEL

Keystore password.

Type
String
Default
none
Defined by
SpnegoLdapProperties
Supports
Spring Expression Language
cas.authn.spnego.ldap.keystore-typeThe type of keystore.
no default

The type of keystore. PKCS12 or JKS. If left blank, defaults to the default keystore type indicated by the underlying Java platform.

Type
String
Default
none
Defined by
SpnegoLdapProperties
cas.authn.spnego.ldap.max-pool-sizeMaximum LDAP connection pool size which the pool can use to grow.
10

Maximum LDAP connection pool size which the pool can use to grow.

Type
Integer
Default
10
Defined by
SpnegoLdapProperties
cas.authn.spnego.ldap.min-pool-sizeMinimum LDAP connection pool size.
3

Minimum LDAP connection pool size. Size the pool should be initialized to and pruned to

Type
Integer
Default
3
Defined by
SpnegoLdapProperties
cas.authn.spnego.ldap.nameName of the LDAP handler.
no default

Name of the LDAP handler.

Type
String
Default
none
Defined by
SpnegoLdapProperties
cas.authn.spnego.ldap.page-sizeRequest that the server return results in batches of a specific size.
0

Request that the server return results in batches of a specific size. See RFC 2696. This control is often used to work around server result size limits. A negative/zero value disables paged requests.

Type
Integer
Default
0
Defined by
SpnegoLdapProperties
cas.authn.spnego.ldap.pool-passivatorYou may receive unexpected LDAP failures, when CAS is configured to authenticate using DIRECT or AUTHENTICATED types and LDAP is locked down to not allow anonymous binds/searches.
BIND
You may receive unexpected LDAP failures, when CAS is configured to authenticate using DIRECT or AUTHENTICATED types and LDAP is locked down to not allow anonymous binds/searches. Every second attempt with a given LDAP connection from the pool would fail if it was on the same connection as a failed login attempt, and the regular connection validator would similarly fail. When a connection is returned back to a pool, it still may contain the principal and credentials from the previous attempt. Before the next bind attempt using that connection, the validator tries to validate the connection again but fails because it’s no longer trying with the configured bind credentials but with whatever user DN was used in the previous step. Given the validation failure, the connection is closed and CAS would deny access by default. Passivators attempt to reconnect to LDAP with the configured bind credentials, effectively resetting the connection to what it should be after each bind request. Furthermore if you are seeing errors in the logs that resemble a 'Operation exception encountered, reopening connection' type of message, this usually is an indication that the connection pool’s validation timeout established and created by CAS is greater than the timeout configured in the LDAP server, or more likely, in the load balancer in front of the LDAP servers. You can adjust the LDAP server session’s timeout for connections, or you can teach CAS to use a validity period that is equal or less than the LDAP server session’s timeout. Accepted values are:
  • NONE: No passivation takes place.
  • BIND: The default behavior which passivates a connection by performing a bind operation on it. This option requires the availability of bind credentials when establishing connections to LDAP.
Type
String
Default
BIND
Defined by
SpnegoLdapProperties
cas.authn.spnego.ldap.prune-periodRemoves connections from the pool based on how long they have been idle in the available queue.
PT2H
Duration

Removes connections from the pool based on how long they have been idle in the available queue. Run the pruning process at the indicated interval.

Type
String
Default
PT2H
Defined by
SpnegoLdapProperties
cas.authn.spnego.ldap.response-timeoutDuration of time to wait for responses.
PT5S
Duration

Duration of time to wait for responses.

Type
String
Default
PT5S
Defined by
SpnegoLdapProperties
cas.authn.spnego.ldap.sasl-authorization-idSASL authorization id.
no default

SASL authorization id.

Type
String
Default
none
Defined by
SpnegoLdapProperties
cas.authn.spnego.ldap.sasl-mechanismThe SASL mechanism.
no default

The SASL mechanism.

Type
String
Default
none
Defined by
SpnegoLdapProperties
cas.authn.spnego.ldap.sasl-mutual-authWhether SASL mutual authentication is enabled.
no default

Whether SASL mutual authentication is enabled.

Type
Boolean
Default
none
Defined by
SpnegoLdapProperties
cas.authn.spnego.ldap.sasl-quality-of-protectionSASL quality of protected.
no default

SASL quality of protected.

Type
String
Default
none
Defined by
SpnegoLdapProperties
cas.authn.spnego.ldap.sasl-realmThe SASL realm.
no default

The SASL realm.

Type
String
Default
none
Defined by
SpnegoLdapProperties
cas.authn.spnego.ldap.sasl-security-strengthSASL security strength.
no default

SASL security strength.

Type
String
Default
none
Defined by
SpnegoLdapProperties
cas.authn.spnego.ldap.search-entry-handlersSearch handlers.
no default

Search handlers.

Type
List<LdapSearchEntryHandlersProperties>
Default
none
Defined by
SpnegoLdapProperties
cas.authn.spnego.ldap.search-entry-handlers[0].case-change.attribute-name-case-changeThe Attribute name case change.
no default

The Attribute name case change.

Type
String
Default
none
Defined by
CaseChangeSearchEntryHandlersProperties
cas.authn.spnego.ldap.search-entry-handlers[0].case-change.attribute-namesThe Attribute names.
no default

The Attribute names.

Type
List<String>
Default
none
Defined by
CaseChangeSearchEntryHandlersProperties
cas.authn.spnego.ldap.search-entry-handlers[0].case-change.attribute-value-case-changeThe Attribute value case change.
no default

The Attribute value case change.

Type
String
Default
none
Defined by
CaseChangeSearchEntryHandlersProperties
cas.authn.spnego.ldap.search-entry-handlers[0].case-change.dn-case-changeThe Dn case change.
no default

The Dn case change.

Type
String
Default
none
Defined by
CaseChangeSearchEntryHandlersProperties
cas.authn.spnego.ldap.search-entry-handlers[0].dn-attribute.add-if-existsThe Add if exists.
no default

The Add if exists.

Type
boolean
Default
none
Defined by
DnAttributeSearchEntryHandlersProperties
cas.authn.spnego.ldap.search-entry-handlers[0].dn-attribute.dn-attribute-nameThe Dn attribute name.
entryDN

The Dn attribute name.

Type
String
Default
entryDN
Defined by
DnAttributeSearchEntryHandlersProperties
cas.authn.spnego.ldap.search-entry-handlers[0].merge-attribute.attribute-namesThe Attribute names.
no default

The Attribute names.

Type
List<String>
Default
none
Defined by
MergeAttributesSearchEntryHandlersProperties
cas.authn.spnego.ldap.search-entry-handlers[0].merge-attribute.merge-attribute-nameThe Merge attribute name.
no default

The Merge attribute name.

Type
String
Default
none
Defined by
MergeAttributesSearchEntryHandlersProperties
cas.authn.spnego.ldap.search-entry-handlers[0].primary-group-id.base-dnThe Base dn.
no default

The Base dn.

Type
String
Default
none
Defined by
PrimaryGroupIdSearchEntryHandlersProperties
cas.authn.spnego.ldap.search-entry-handlers[0].primary-group-id.group-filterThe Group filter.
(&(objectClass=group)(objectSid={0}))

The Group filter.

Type
String
Default
(&(objectClass=group)(objectSid={0}))
Defined by
PrimaryGroupIdSearchEntryHandlersProperties
cas.authn.spnego.ldap.search-entry-handlers[0].recursive.merge-attributesThe Merge attributes.
no default

The Merge attributes.

Type
List<String>
Default
none
Defined by
RecursiveSearchEntryHandlersProperties
cas.authn.spnego.ldap.search-entry-handlers[0].recursive.search-attributeThe Search attribute.
no default

The Search attribute.

Type
String
Default
none
Defined by
RecursiveSearchEntryHandlersProperties
cas.authn.spnego.ldap.search-entry-handlers[0].search-referral.limitThe default referral limit.
10

The default referral limit.

Type
int
Default
10
Defined by
FollowReferralSearchEntryHandlersProperties
cas.authn.spnego.ldap.search-entry-handlers[0].search-result.limitThe default referral limit.
10

The default referral limit.

Type
int
Default
10
Defined by
FollowResultSearchEntryHandlersProperties
cas.authn.spnego.ldap.search-entry-handlers[0].typeThe type of search entry handler to choose.
no default
The type of search entry handler to choose. Available values are as follows:
  • FOLLOW_SEARCH_REFERRAL: Provides handling of an ldap referral for search operations.
  • FOLLOW_SEARCH_RESULT_REFERENCE: Provides handling of an ldap continuation reference for search operations.
  • ACTIVE_DIRECTORY: Process the entry results fetched from active directory and check for account status controls for disabled/expired accounts, etc.
  • OBJECT_GUID: Object guid search entry handler. Handles the objectGUID attribute fetching and conversion.
  • OBJECT_SID: Object sid search entry handler. Handles the objectSid attribute fetching and conversion.
  • CASE_CHANGE: Case change search entry handler. Provides the ability to modify the case of search entry DNs, attribute names, and attribute values.
  • DN_ATTRIBUTE_ENTRY: DN attribute entry handler. Adds the entry DN as an attribute to the result set. Provides a client side implementation of RFC 5020.
  • MERGE: Merge search entry handler. Merges the values of one or more attributes into a single attribute.
  • PRIMARY_GROUP: Primary group search handler. Constructs the primary group SID and then searches for that group and puts it's DN in the memberOf attribute of the original search entry.
  • RANGE_ENTRY: Range entry search handler. Rewrites attributes returned from Active Directory to include all values by performing additional searches.
  • RECURSIVE_ENTRY: Recursive entry search handler. This recursively searches based on a supplied attribute and merges those results into the original entry.
  • MERGE_ENTRIES: Merge entries handler. Merges the values of one or more attributes in all entries into a single attribute. The merged attribute may or may not already exist on the entry. If it does exist it's existing values will remain intact.
Type
LdapSearchEntryHandlersProperties.SearchEntryHandlerTypes
Default
none
Defined by
LdapSearchEntryHandlersProperties
cas.authn.spnego.ldap.subtree-searchWhether subtree searching is allowed.
true

Whether subtree searching is allowed.

Type
Boolean
Default
true
Defined by
SpnegoLdapProperties
cas.authn.spnego.ldap.trust-certificatesPath of the trust certificates to use for the SSL connection.
no default

Path of the trust certificates to use for the SSL connection. Ignores keystore-related settings when activated and used.

Type
String
Default
none
Defined by
SpnegoLdapProperties
cas.authn.spnego.ldap.trust-managerTrust Manager options.
no default
Trust Manager options. Trust managers are responsible for managing the trust material that is used when making LDAP trust decisions, and for deciding whether credentials presented by a peer should be accepted. Accepted values are:
  • DEFAULT: Enable and force the default JVM trust managers.
  • ANY: Trust any client or server.
Type
String
Default
none
Defined by
SpnegoLdapProperties
cas.authn.spnego.ldap.trust-storePath to the keystore used to determine which certificates or certificate authorities should be trusted.
no default
SpEL

Path to the keystore used to determine which certificates or certificate authorities should be trusted. Used when connecting to an LDAP server via LDAPS or startTLS connection. If left blank, the default truststore for the Java runtime is used.

Type
String
Default
none
Defined by
SpnegoLdapProperties
Supports
Spring Expression Language
cas.authn.spnego.ldap.trust-store-passwordPassword needed to open the truststore.
no default
SpEL

Password needed to open the truststore.

Type
String
Default
none
Defined by
SpnegoLdapProperties
Supports
Spring Expression Language
cas.authn.spnego.ldap.trust-store-typeThe type of trust keystore that determines which certificates or certificate authorities are trusted.
no default

The type of trust keystore that determines which certificates or certificate authorities are trusted. Types depend on underlying java platform, typically PKCS12 or JKS. If left blank, defaults to the default keystore type indicated by the underlying Java platform.

Type
String
Default
none
Defined by
SpnegoLdapProperties
cas.authn.spnego.ldap.use-start-tlsWhether TLS should be used and enabled when establishing the connection.
false

Whether TLS should be used and enabled when establishing the connection.

Type
Boolean
Default
false
Defined by
SpnegoLdapProperties
cas.authn.spnego.ldap.validate-on-checkoutWhether connections should be validated when loaned out from the pool.
true

Whether connections should be validated when loaned out from the pool.

Type
Boolean
Default
true
Defined by
SpnegoLdapProperties
cas.authn.spnego.ldap.validate-periodPeriod at which pool should be validated.
PT5M
Duration

Period at which pool should be validated.

Type
String
Default
PT5M
Defined by
SpnegoLdapProperties
cas.authn.spnego.ldap.validate-periodicallyWhether connections should be validated periodically when the pool is idle.
true

Whether connections should be validated periodically when the pool is idle.

Type
Boolean
Default
true
Defined by
SpnegoLdapProperties
cas.authn.spnego.ldap.validate-timeoutPeriod at which validation operations may time out.
PT5S
Duration

Period at which validation operations may time out.

Type
String
Default
PT5S
Defined by
SpnegoLdapProperties
cas.authn.spnego.ldap.validator.attribute-nameAttribute name to use for the compare validator.
objectClass

Attribute name to use for the compare validator.

Type
String
Default
objectClass
Defined by
LdapValidatorProperties
cas.authn.spnego.ldap.validator.attribute-valueAttribute values to use for the compare validator.
top

Attribute values to use for the compare validator.

Type
String
Default
top
Defined by
LdapValidatorProperties
cas.authn.spnego.ldap.validator.base-dnBase DN to use for the search request of the search validator.
no default

Base DN to use for the search request of the search validator.

Type
String
Default
none
Defined by
LdapValidatorProperties
cas.authn.spnego.ldap.validator.dnDN to compare to use for the compare validator.
no default

DN to compare to use for the compare validator.

Type
String
Default
none
Defined by
LdapValidatorProperties
cas.authn.spnego.ldap.validator.scopeSearch scope to use for the search request of the search validator.
OBJECT

Search scope to use for the search request of the search validator.

Type
String
Default
OBJECT
Defined by
LdapValidatorProperties
cas.authn.spnego.ldap.validator.search-filterSearch filter to use for the search request of the search validator.
(objectClass=*)

Search filter to use for the search request of the search validator.

Type
String
Default
(objectClass=*)
Defined by
LdapValidatorProperties
cas.authn.spnego.ldap.validator.typeDetermine the LDAP validator type.
search

Determine the LDAP validator type.

The following LDAP validators can be used to test connection health status:
  • search: Validates a connection is healthy by performing a search operation. Validation is considered successful if the search result size is greater than zero.
  • none: No validation takes place.
  • compare: Validates a connection is healthy by performing a compare operation.
Type
String
Default
search
Defined by
LdapValidatorProperties
cas.authn.spnego.spnego-attribute-nameIn case LDAP is used to validate clients, this is the attribute that indicates the host.
distinguishedName

In case LDAP is used to validate clients, this is the attribute that indicates the host.

Type
String
Default
distinguishedName
Defined by
SpnegoProperties

Required settings may be needed to activate or affect the feature; review them even when they have a default. Optional settings only need to be set to change a default or to turn on the behavior they control. Third party settings belong to libraries such as Spring Boot that CAS builds on; their own documentation may have more detail.

LDAP & Active Directory

LDAP Scriptable Search Filter

LDAP search filters can point to an external Groovy script to dynamically construct the final filter template.

The script itself may be designed as:



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import org.ldaptive.*
import org.springframework.context.*

def run(Object[] args) {
    def (filter,parameters,applicationContext,logger) = args

    logger.info("Configuring LDAP filter")
    filter.setFilter("uid=something")
}

The following parameters are passed to the script:

Parameter Description
filter FilterTemplate to be updated by the script and used for the LDAP query.
parameters Map of query parameters which may be used to construct the final filter.
applicationContext Reference to the Spring ApplicationContext reference.
logger The object responsible for issuing log messages such as logger.info(...).

To prepare CAS to support and integrate with Apache Groovy, please review this guide.

Notes on configuration

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.

: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.

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, especially 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.

Logging

To enable additional logging, configure the log4j configuration file to add the following levels:



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...
<Logger name="jcifs.spnego" level="debug" additivity="false">
    <AppenderRef ref="casConsole"/>
    <AppenderRef ref="casFile"/>
</Logger>
...

Troubleshooting

  • Failure unspecified at GSS-API level


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Caused by: GSSException: Failure unspecified at GSS-API level (Mechanism level: Invalid argument (400) - Cannot find key of appropriate type to decrypt AP REP - AES256 CTS mode with HMAC SHA1-96)
        at sun.security.jgss.krb5.Krb5Context.acceptSecContext(Unknown Source)
        at sun.security.jgss.GSSContextImpl.acceptSecContext(Unknown Source)
        at sun.security.jgss.GSSContextImpl.acceptSecContext(Unknown Source)
        ... 280 more
Caused by: KrbException: Invalid argument (400) - Cannot find key of appropriate type to decrypt 
AP REP - AES256 CTS mode with HMAC SHA1-96
        at sun.security.krb5.KrbApReq.authenticate(Unknown Source)
        at sun.security.krb5.KrbApReq.<init>(Unknown Source)
        at sun.security.jgss.krb5.InitSecContextToken.<init>(Unknown Source)
        ... 283 more

It’s very likely that you have the wrong path to .keytab file. The KVNO in the keytab file must be identical with the KVNO stored in the Active Directory. Active Directory is raising the KVNO with every execution of ktpass, as part of its msDS-KeyVersionNumber.

Other possible causes include:

  1. The service principal in the in the CAS configuration is not identical with that from the keytab. (param /princ from ktpass)
  2. There is no key for the enctype sent with the ticket by Active Directory. (param /crypto from ktpass and set in the krb5.conf/permitted_enctypes+default_tkt_enctypes).
  3. The KVNO from the ticket is different than the KVNO in the keytab (param /kvno from ktpass).