The API Gateway can request an authentication decision from a Security Assertion Markup Language (SAML) Policy Decision Point (PDP) for an authenticated client using the SAML Protocol (SAMLP). In such cases, the API Gateway presents evidence to the PDP in the form of some user credentials, such as the Distinguished Name of a client's X.509 certificate.
The PDP decides whether to authenticate the end-user. It then creates an authentication assertion, signs it, and returns it to the API Gateway in a SAML Protocol response. The API Gateway can then perform a number of checks on the response, such as validating the PDP signature and certificate, and examining the assertion. It can also insert the SAML authentication assertion into the message for consumption by a downstream Web Service.
This section describes how the API Gateway should package the SAMLP request before sending it to the SAML PDP.
SAML PDP URL Sets
You can configure a group of SAML PDPs to which the API Gateway connects in a round-robin fashion if one or more of the PDPs are unavailable. This is known as a SAML PDP URL Set. You can configure a SAML PDP URL Set using this screen or under the External Connections node in the Policy Studio tree. For more details, see the topic on Configuring URL Groups.
You can configure the following general fields:
-
SAML PDP URL Set:
Click the button on the right, and select a previously configured SAML PDP URL Set in the tree. To add a URL Set, right-click the SAML PDP URL Sets tree node, and select Add a URL Set. Alternatively, you can configure a SAML PDP URL Set under the External Connections node in the Policy Studio tree.
-
SOAPAction:
Enter the SOAP Action required to send SAML Protocol requests to the PDP. Click the Use Default button to use the following default SOAP Action as specified by the SAML Protocol:
http://www.oasis-open.org/committees/security
-
SAML Version:
Select the SAML version to use in the SAMLP request.
-
Signing Key:
If the SAMLP request is to be signed, click the Signing Key button, and select the appropriate signing key from the Certificate Store.
SAML Subject:
The specified details describe the subject of the SAML assertion. Complete the following fields:
-
Subject Attribute:
Select the message attribute that contains the name of an authenticated user name. By default, the
authentication.subject.idmessage attribute is selected, which contains the user name of the authenticated user. -
Subject Format:
Select the format of the message attribute selected in the Subject Attribute field above. You do not need to select a format if the Subject Attribute field is set to
authentication.subject.id
Subject Confirmation:
The settings on the Confirmation Method tab determine
how the <SubjectConfirmation> block of the
SAML assertion is generated. When the assertion is consumed by a
downstream Web Service, the information contained in the
<SubjectConfirmation> block can be used
to authenticate the end-user that authenticated to the API Gateway,
or the issuer of the assertion, depending on what is configured.
The following is a typical <SubjectConfirmation> block:
<saml:SubjectConfirmation>
<saml:ConfirmationMethod>
urn:oasis:names:tc:SAML:1.0:cm:holder-of-key
</saml:ConfirmationMethod>
<dsig:KeyInfo xmlns:dsig="http://www.w3.org/2000/09/xmldsig#">
<dsig:X509Data>
<dsig:X509SubjectName>CN=oracle</dsig:X509SubjectName>
<dsig:X509Certificate>
MIICmzCCAY ...... mB9CJEw4Q=
</dsig:X509Certificate>
</dsig:X509Data>
</dsig:KeyInfo>
</saml:SubjectConfirmation>
</saml:SubjectConfirmation>
You must configure the following fields on the Subject Confirmation tab:
Method:
The selected value determines the value of the
<ConfirmationMethod> element. The following
table shows the available methods, their meanings, and their respective
values in the <ConfirmationMethod> element:
| Method | Meaning | Value |
|---|---|---|
| Holder Of Key |
Inserts a <SubjectConfirmation>
into the SAMLP request. The
<SubjectConfirmation> contains
a <dsig:KeyInfo> section with the
certificate of the user selected to sign the SAMLP request.
The user selected to sign the SAMLP request must be the
authenticated subject (authentication.subject.id).
SubjectConfimration block. Alternatively,
select the Include Key Name option
if only the key name is to be included.
|
urn:oasis:names:tc:SAML:1.0:cm:holder-of-key |
| Bearer |
Inserts a <SubjectConfirmation>
into the SAMLP request.
|
urn:oasis:names:tc:SAML:1.0:cm:bearer |
| SAML Artifact |
Inserts a <SubjectConfirmation>
into the SAMLP request.
|
urn:oasis:names:tc:SAML:1.0:cm:artifact |
| Sender Vouches |
Inserts a <SubjectConfirmation>
into the SAMLP request. A user must sign the SAMLP request.
|
urn:oasis:names:tc:SAML:1.0:cm:bearer |
If the Method field is left blank, no
<ConfirmationMethod> block is inserted into
the assertion.
Include Certificate:
Select this option if you wish to include the SAML subject's certificate
in the <KeyInfo> section of the
<SubjectConfirmation> block.
Include Key Name:
Alternatively, if you do not want to include the certificate, select this
option to only include the key name in the <KeyInfo> section.
This tab configures the SAMLP Response returned from the SAML PDP. The following fields are available:
SOAP Actor/Role:
If the SAMLP response from the PDP contains a SAML authentication assertion, the API Gateway can extract it from the response and insert it into the downstream message. The SAML assertion is inserted into the WS-Security block identified by the specified SOAP actor/role.
Drift Time:
The SAMLP request to the PDP is timestamped by the API Gateway. To account for differences in the times on the machines running the API Gateway and the SAML PDP the specified time is subtracted from the time at which the API Gateway generates the SAMLP request.
