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Partner Directory – Sender Partner Connecting with Client Certificate Authentication

We enhance the scenario described in the blog Partner Directory – Step-by-Step Example. We add a third partner who connects to the integration flow via client certificate authentication . We show how the necessary configuration of the integration tenant can be done with help of the Partner Directory OData API. Especially we introduce the OData entity type “CertificateUserMapping”.

How inbound client certificate authentication works is described in Client Certificate Authentication.

Example Scenario

In the previous blog Partner Directory – Step-by-Step Example we had two sender partners (“Sender_BASIC” and “SenderOAUTH”) which connect to the integration flow either via BASIC or OAUTH authentication. Now, we add a third partner with partner ID “Sender_CERT” which uses client-certificate authentication. See the following diagram.

Diagram 1: Scenario

We simulate the sender „Sender_CERT“ with help of SoapUI instead of using Postman because SoapUI has better support for client certificate authentication.

Precondition

For the client-certificate authentication, you need a key-pair with a X.509 certificate chain which is trusted by the SAP Cloud Integration Load Balancer. We cannot provide such a key-pair due to security reasons.

The list of trusted CAs of the Load Balancer is given in Load Balancer Root Certificates Supported by SAP.

In the following we assume that you have a JCEKS client keystore containing such a key-pair with an adequate certificate chain assigned.

The client keystore must also contain the “Baltimore CyberTrust Root” CA certificate to trust the X.509 certificate chain of the Load Balancer key-pair. You can download this certificate from https://baltimore-cybertrust-root.chain-demos.digicert.com/info/index.html.  The following screen shot taken from KeyStore Explorer tool shows the keystore content.

Screen Shot 1: Client Keystore Containing the “Baltimore CyberTrust Root” CA Certificate and the Client Key-Pair

Ensure that the key-pair entry has a certificate chain assigned containing at least the client certificate and the intermediate CA certificate. You can see the certificate chain in the KeyStore Explorer by double clicking on the key-pair entry.

Screen Shot 2: Client Certificate Chain Assigned to Key-Pair Entry

Additionally, you need SoapUI for executing a call to the integration flow with client certificate authentication. You can get an open source version from https://www.soapui.org/downloads/soapui.html. We used SoapUI version 5.3.0.

Step-By-Step Configuration

We describe step-by-step what you must configure for the new sender “Sender_CERT”.

Step 1: Create Certificate User Mapping

A certificate-user mapping must be created in the SAP Cloud Integration tenant. This can either be done via the Cloud Integration WEB-UI or programmatically via an OData request. We use here the OData API.

Step 1.1: Export the Client Certificate from the Client Keystore

Use KeyStore Explorer to export the client certificate. Mark the key-pair entry and choose the menu option >Export >Export Certificate Chain

In the shown pop-up keep the settings “Head Only”, “X.509”, and “PEM” as shown in the following screen shot.

Screen Shot 3: Export Client Certificate with Help of Keystore Explorer

Step 1.2: Call Odata API

Call the OData API for the certificate-user mapping as described in Addressing Certificate-to-User Mappings using Postman (See also chapter “Setp 3: Adding Partner Information to the Partner Directory“ of the previous blog Partner Directory – Step-by-Step Example.

Use as User the value “user_for_sender_cert” as shown in the following example request body.

{"Id":"12", "User":"user_for_sender_cert", "Certificate":"LS0tLS1CRUdJTiBDRVJUSUZJQ0FURS0tLS...QT0NCi0tLS0tRU5EIENFUlRJRklDQVRFLS0tLS0NCg=="}

OData Request Body Snippet for Creating a Certificate-User Mapping

Note, that you must base64 encode the client certificate; but you can use a dummy value for the “Id” property.

The request address is given by

https:<tmn>/api/v1/CertificateUserMappings

Request Address for Creating a Certificte-User Mapping

Check in the Cloud Integration WEB UI that the certificate-user mapping was created.

Step 2: Create Authorized User

As for the other sender partners, you create an Authorized User entry in the Partner Directory which ensures that the user “user_for_sender_cert” gets the role “ESBMessaging.send” assigned for executing integration flows and which ensures that not any other partners can use this user.

See chapter “Step 3.2 Authorized user” of the previous blog Partner Directory – Step-by-Step Example.

Perform a POST call to the address

https://<tmn>/api/v1/AuthorizedUsers

with the body

{"Pid":"Sender_CERT","User":"user_for_sender_cert"}

You can also find further information in the documentation  Requests for String Parameter, Binary Parameter, and Authorized User.

Call the Integration Flow

Before we call the integration flow with the new sender using SoapUI, verify that the Partner Directory Integration Flow and the two receiver integration flows of the previous blog Partner Directory – Step-by-Step Example are deployed. Additionally, verify that the following two String Parameter entries for looking up the receiver addresses exist in the Partner Directory (See chapter “Step 3.1 Creating/Updating/Deleting a String Parameter Entry” of the previous blog).

{ "Pid": "Receiver_1", "Id": "ADDRESS", "Value": “https://<receiver_iflmap>/cxf/receiver_1”}
{ "Pid": "Receiver_2", "Id": "ADDRESS", "Value": “https://<receiver_iflmap>/cxf/receiver_2”}

String Parameter Entries in the Partner Directory for Looking-Up the Receiver Address

Step 1: SoapUI SSL Settings

In SoapUI go to the menu option

> File > Preferences

and select the “SSL Settings” tab.

Enter in the “Keystore” field the path to the client keystore.

Enter the password of the client keystore.

And tick the “requires client authentication” field.

Screen Shot 4: SoapUI SSL Settings for Client Certificate Authentication

Step 2: SoapUI Proxy Settings

Further, select the “Proxy Settings” tab and enter your proxy, if necessary.

Screen Shot 5: SoapUI Proxy Settings

Step 3: Execute Request in Rest Project

Press the button “REST” in the button bar for creating a new Rest project.

In the pop-up, enter the URL of the integration flow endpoint

https:///http/partner_directory_test

In the Request View, chose the “POST” Method and the Media Type “text/xml” and enter the following message body.

<Message>
    <SenderPartnerId>Sender_CERT</SenderPartnerId>
    <ReceiverPartnerId>Receiver_1</ReceiverPartnerId>
    <Content>test</Content>
</Message>

Payload 1: Request body for Receiver_1

Press the “Submit request” button. The following screen shot shows the request and response in Soap UI.

Screen Shot 6: Executing the Request in SoapUI

If you use the following request body for the receiver “Receiver_2”,

<Message>
   <SenderPartnerId>Sender_CERT</SenderPartnerId>
    <ReceiverPartnerId>Receiver_2</ReceiverPartnerId>
    <Content>test</Content>
</Message>

Payload 2: Request body for Receiver_2

then you get as response the following response body

<Message>
    <SenderPartnerId>Sender_CERT</SenderPartnerId>
    <ReceiverPartnerId>Receiver_2</ReceiverPartnerId>
    <Content>Receiver_2 greets Sender_CERT</Content>
</Message>

Payload 3: Response Body

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