Federation Guides › Partnership Federation Guide › URLs to Initiate Single Sign-on

URLs to Initiate Single Sign-on

Links to Servlets which Initiate Single Sign-on

When designing a site for federated content, that site includes a page with specific links to trigger single sign-on. These links are URLs to servlets for the Single Sign-on service or the AuthnRequest Service.

To initiate single sign-on, the user can begin at the asserting or relying party. Configure the appropriate links at each site to initiate single sign-on operation.

Producer-initiated SSO (SAML 1.1)

At the producer, create pages that contain links that direct the user to the consumer site. Each link represents an intersite transfer URL. The user has to visit the intersite transfer URL. The URL makes a request to the producer-side web Agent before the user is redirected to the consumer site.

For SAML Artifact and POST profile, the syntax for the intersite transfer URL is:

http://producer_host:port/affwebservices/public/intersitetransfer?
CONSUMERID=consumer_entity_ID&TARGET=http://consumer_site/target_url

The variables and query parameters in the previous intersite transfer URL are as follows:

producer_host:port

Specifies the server and port number where the user is authenticated.

CONSUMERID

(Required) Identifies the consumer. On the producer side, the producer-to-consumer partnership has a name, and the remote consumer entity has an ID. The CONSUMERID is the entity ID of the remote consumer. The entity ID is case-sensitive. Enter it exactly as it appears in the Administrative UI.

You can use the parameter NAME in place of CONSUMERID, but not both.

If you use NAME, specify the name of the producer-to-consumer partnership as defined at the producer.

consumer_entity_ID

Identifies the consumer site the user wants to visit from the producer site. The entity ID is case-sensitive. Enter it exactly as it appears in the Administrative UI.

TARGET

(Optional) Identifies the requested target resource at the consumer.

The TARGET parameter is optional. You are required to define the target; however, you can define it in the consumer-side partnership instead of the intersite transfer URL. The target is defined in the Application Integration step of the Partnership wizard. Be sure to define the target in the URL or in the partnership.

consumer_site

Specifies the server at the consumer site.

target_url

Indicates the target application at the consumer site.

Note: Query parameters for the SAML Artifact binding must use HTTP-encoding.

Example of an intersite transfer URL for the Artifact and POST profile:

http://www.smartway.com/affwebservices/public/intersitetransfer?
CONSUMERID=ahealthco&TARGET=http://www.ahealthco.com:85/
smartway/index.jsp

IdP-initiated SSO (SAML 2.0 Artifact or POST)

If a user visits a CA SiteMinder® Identity Provider before going to the Service Provider, an unsolicited response at the Identity Provider must be initiated. To initiate an unsolicited response, create a hard-coded link that generates an HTTP Get request that CA SiteMinder® accepts. This HTTP Get request must contain a query parameter that provides the Service Provider ID. The Identity Provider must generate the SAML assertion response. A user clicks this link to initiate the unsolicited response.

Note: This information applies to Artifact or POST bindings.

To specify the use of artifact or POST profile in the unsolicited response, the syntax for the unsolicited response link is:

http://idp_server:port/affwebservices/public/saml2sso?SPID=SP_ID&
ProtocolBinding=URI_for_binding&RelayState=target_URL

idp_server:port

Identifies the web server and port hosting CA SiteMinder®.

SP_ID

Specifies the Entity ID of the Service Provider defined in the partnership. The entity ID is case-sensitive. Enter it exactly as it appears in the Administrative UI.

URI_for_binding

Identifies the URI of the POST or Artifact binding for the ProtocolBinding element. The SAML 2.0 specification defines this URI.

The URI for the artifact binding, as specified by the SAML 2.0 specification is:
urn:oasis:names:tc:SAML:2.0:bindings:HTTP-Artifact
The URI for the POST binding, as specified by the SAML 2.0 specification is:
urn:oasis:names:tc:SAML:2.0:bindings:HTTP-POST

You do not need to set this parameter for HTTP-POST single sign-on.

Note: A binding must also be enabled for the partnership for the request to work.

target_URL

Specifies the URL of the federation resource target at the Service Provider.

Note the following:

If you do not include the ProtocolBinding query in the link, use the one binding configured in the Service Provider properties
When Artifact and POST are enabled in the Service Provider properties, POST is the default. Therefore, if you only want to use Artifact binding, include the ProtocolBinding query parameter in the link.

Important! If you configure indexed endpoint support for Assertion Consumer Services, the value of the ProtocolBinding query parameter overrides the binding for the Assertion Consumer Service.

Unsolicited Response Query Parameters Used by the IdP

An unsolicited response that initiates single sign-on from the IdP can include the following query parameters:

SPID: (Required) Specifies the ID of the Service Provider where the Identity Provider sends the unsolicited response. The entity ID is case-sensitive. Enter it exactly as it appears in the Administrative UI.
ProtocolBinding: Specifies the ProtocolBinding element in the unsolicited response. This element specifies the protocol for sending the assertion response to the Service Provider. If the Service Provider is not configured to support the specified protocol binding, the request fails.
RelayState: Indicates the URL of the target resource at the Service Provider. By including this query parameter, it tells the IdP to redirect the user the appropriate resource at the Service Provider. This query parameter can be used in place of specifying a target URL when configuring single sign-on.

Required Use of the ProtocolBinding Query Parameter

The ProtocolBinding query parameter is required only if the artifact and POST binding are enabled for the Service Provider properties. In addiiton, the user wants to only use artifact binding.

The URI for the artifact binding is:
urn:oasis:names:tc:SAML:2.0:bindings:HTTP-Artifact
The URI for the POST binding is:
urn:oasis:names:tc:SAML:2.0:bindings:HTTP-POST

You do not need to set this parameter for HTTP-POST single sign-on.

Note: HTTP coding the query parameters is not necessary.

Optional Use of the ProtocolBinding Query Parameter

When you do not use the ProtocolBinding query parameter, the following information applies:

If only one binding is enabled for the Service Provider and the ProtocolBinding is not specified in the unsolicited response, the enabled binding is used.
If both bindings are enabled for the Service Provider and the ProtocolBinding is not specified in the unsolicited response, the POST binding is the default.

Example: Unsolicited Response without ProtocolBinding

The link redirects the user to the Single Sign-on service. Included in this link is the Service Provider identity, which the SPID query parameter specifies. The ProtocolBinding query parameter is not present. After the user clicks this hard-coded link, they are redirected to the Single Sign-on service.

http://fedsrv.fedsite.com:82/affwebservices/public/saml2sso?
SPID=http%3A%2F%2Ffedsrv.acme.com%2Fsmidp2for90

Example: Unsolicited Response with ProtocolBinding

The link redirects the user to the Single Sign-on service. Included in this link is the Service Provider identity, which the SPID query parameter specifies and the artifact binding is being used. After the user clicks this hard-coded link, they are redirected to local Single Sign-on service.

http://idp-ca:82/affwebservices/public/saml2sso?SPID=
http%3A%2F%2Ffedsrv.acme.com%2Fsmidp2for90&
ProtocolBinding=urn:oasis:names:tc:SAML:2.0:bindings:HTTP-Artifact

ForceAuthn and IsPassive Processing at the IdP

If Service Provider initiates single sign-on, the Service Provider can include a ForceAuthn or IsPassive query parameter in an AuthnRequest message.

When a Service Provider includes ForceAuthn or IsPassive in the AuthnRequest, a CA SiteMinder® Identity Provider handles these query parameters as follows:

ForceAuthn Handling

When a Service Provider includes ForceAuthn=True in the AuthnRequest message, a CA SiteMinder® Identity Provider challenges the user for their credentials. The challenge even when a CA SiteMinder® session exists.

IsPassive Handling

A CA SiteMinder® IdP does not support passive authentication. When a Service Provider includes IsPassive in the AuthnRequest and the Identity Provider cannot honor it, the IdP sends back one of these SAML responses:

If IsPassive=True in the AuthnRequest message and there is no session, the Identity Provider returns an error message. CA SiteMinder® requires a session.
If IsPassive=True in the AuthnRequest message and there is a session, the Identity Provider returns the assertion.
If IsPassive and ForceAuthn are in the AuthnRequest message and both are set to True, the CA SiteMinder® Identity Provider returns an error. IsPassive and ForceAuthn are mutually exclusive.

SP-initiated SSO (SAML 2.0)

SP-initiated SSO requires that you have an HTML page at the Service Provider containing hard-coded links to the AuthnRequest service at the Service Provider. The links redirect the user to the Identity Provider to be authenticated and determining what is included in the AuthnRequest itself.

This information applies to Artifact or POST bindings.

The hard-coded link that the user selects must contain specific query parameters, which are used in an HTTP GET request to the AuthnRequest service.

Note: The page with these hard-coded links has to reside in an unprotected realm.

To specify the use of artifact or profile binding for the transaction, the syntax for the link is:

http://sp_server:port/affwebservices/public/saml2authnrequest?
ProviderID=IdP_ID&ProtocolBinding=URI_of_binding&
RelayState=target_URL

sp_server:port

Specifies the server and port number at the Service Provider that is hosting CA SiteMinder Federation.

IdP_ID

Specifies the identity that is assigned to the Identity Provider. The entity ID is case-sensitive. Enter it exactly as it appears in the Administrative UI.

URI_of_binding

Identifies the URI of the POST or Artifact binding for the ProtocolBinding element. The SAML 2.0 specification defines this URI.

The URI for the artifact binding is:
urn:oasis:names:tc:SAML:2.0:bindings:HTTP-Artifact
The URI for the POST binding is:
urn:oasis:names:tc:SAML:2.0:bindings:HTTP-POST

You do not need to set this parameter for HTTP-POST single sign-on.

Also, enable a binding for the partnership for the request to work.

target_URL

Specifies the URL of the federation target at the Service Provider.

Note the following information:

If you do not include the ProtocolBinding query parameter in the AuthnRequest link, the default binding is the one defined for the partnership. If you have both bindings defined in the partnership, then no binding is passed in the AuthnRequest. As a result, the default binding at the Identity Provider is used.
If the artifact and POST bindings are enabled for the partnership but you only want to use artifact binding, include the ProtocolBinding query parameter in the link.

AuthnRequest Query Parameters Used by an SP

The query parameters a CA SiteMinder® SP can use in the links to the AuthnRequest Service are as follows:

ProviderID (required)

Entity ID of the Identity Provider where the AuthnRequest Service sends the AuthnRequest message. The entity ID is case-sensitive. Enter it exactly as it appears in the Administrative UI.

ProtocolBinding

Specifies the ProtocolBinding element in the AuthnRequest message. This element specifies the protocol for returning the SAML response from the Identity Provider. If the specified Identity Provider is not configured to support the specified protocol binding, the request fails.

If you use this parameter in the AuthnRequest, you cannot include the AssertionConsumerServiceIndex parameter also. They are mutually exclusive.

ForceAuthn

Instructs the Identity Provider that it must authenticate a user directly instead of relying on an existing security context. Use this query parameter when the Identity Provider is using CA SiteMinder Federation, not if it is using third-party federation software.

If the SP sets ForceAuthn=True in the AuthnRequest message, and a session exists for a particular user, the Identity Provider challenges the user. If the user successfully authenticates, the IdP sends the identity information from the existing session in the assertion. The Identity Provider discards the session that it generates for the reauthentication.
If the SP sets ForceAuthn=True in the AuthnRequest message and there is no session, the IdP challenges the user. If the user successfully authenticates, a session is established.

Example

http://sp1.demo.com:81/affwebservices/public/saml2authnrequest?
ProviderID=idp1.example.com&ForceAuthn=yes

IsPassive

Instructs the Identity Provider to log in the user without challenging the user for credentials or interacting with the user in any way. A CA SiteMinder® Identity Provider does not honor this query parameter unless the user has a session. If the user does not have a session, the Identity Provider returns an error.

AssertionConsumerServiceIndex

Specifies the index of the endpoint acting as the Assertion Consumer Service. The index tells the Identity Provider where to send the assertion response.

If you use this parameter in the AuthnRequest, do not include the ProtocolBinding parameter also. This parameter and the ProtocolBinding parameter are mutually exclusive. The Assertion Consumer Service has its own protocol binding, which could conflict with the ProtocolBinding parameter.

RelayState

Indicates the URL of the target resource at the Service Provider. By including this query parameter, it tells the Service Provider where to send the user. Otherwise, the default target for the partnership is used.

Required Use of the ProtocolBinding Query Parameter

The ProtocolBinding parameter is required if the artifact and POST bindings are enabled for the partnership, and the user wants to use only the artifact binding.

The URI for the artifact binding is:
urn:oasis:names:tc:SAML:2.0:bindings:HTTP-Artifact
The URI for the POST binding is:
urn:oasis:names:tc:SAML:2.0:bindings:HTTP-POST

You do not need to set this parameter for HTTP-POST single sign-on.

Optional Use of ProtocolBinding

If you do not use the ProtocolBinding query parameter the following conditions apply:

If only one binding is enabled for the partnership and the ProtocolBinding query parameter is not specified, the enabled binding for the partnership is used.
If both bindings are enabled and the ProtocolBinding query parameter is not specified, POST binding is used as the default.

Note: You do not need to HTTP-encode the query parameters.

Example: AuthnRequest Link without the ProtocolBinding Query Parameter

This sample link goes to the AuthnRequest service. The link specifies the Identity Provider in the ProviderID query parameter.

http://ca.sp.com:90/affwebservices/public/saml2authnrequest?
ProviderID=http%3A%2F%2Ffedsrv.acme.com%2Fsmidp2for90

After a user clicks the link at the Service Provider, CA SiteMinder® passes a request for an AuthnRequest message.

Example: AuthnRequest Link with the ProtocolBinding Query Parameter

http://ca.sp.com:90/affwebservices/public/saml2authnrequest?
ProviderID=http%3A%2F%2Ffedsrv.acme.com%2Fsmidp2for90&
ProtocolBinding=urn:oasis:names:tc:SAML:2.0:bindings:HTTP-Artifact

After a user clicks the link at the Service Provider, CA SiteMinder® passes a request for an AuthnRequest message.

IP-initiated Single Sign-on (WSFED)

A user can visit the Identity Provider (IP) before going to the Resource Partner (RP). If the user visits the Identity Provider first, a link must generate an HTTP Get request. The hard-coded link points to the passive requester service at the IP. The request contains the RP Provider ID and optionally other parameters.

The syntax for the link is:

https://ip_server:port/affwebservices/public/wsfedsso?wa=wsignin1.0&wtrealm=rp_id

ip_server:port: Specifies the server and port number of the system at the Identity Partner. The system is hosting the Web Agent Option Pack or the SPS federation gateway, depending on which component is installed in your federation network.
rp_id: The ID of the RP. The entity ID is case-sensitive. Enter it exactly as it appears in the Administrative UI.

RP-initiated Single Sign-on (WSFED)

When a user starts at the RP to initiate single sign-on, typically the user selects from a list of IPs. The site selection page is in an unprotected realm.

The link on the site selection page points to the passive requester service at an IP. After the link is selected, the RP redirects the user to the IP to get the assertion.