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saml-2.0sustainsys-saml2

SAML error "SignatureStatus: NOT_PRESENT"

UPDATE

I found that if I add a trusted cert to SPOptions.ServiceCertificates and set SPOptions.AuthenticateRequestSigningBehavior = Sustainsys.Saml2.Configuration.SigningBehavior.IfIdpWantAuthnRequestsSigned; and set IdentityProvider.WantAuthnRequestsSigned = true, the signature element is included.

Original Question:

Having troubles connecting to an IDP with the following AuthnRequest:

<saml2p:AuthnRequest xmlns:saml2p="urn:oasis:names:tc:SAML:2.0:protocol" xmlns:saml2="urn:oasis:names:tc:SAML:2.0:assertion" ID="idf299bf8aa08542d193e022cb047e5ecc" Version="2.0" IssueInstant="2019-07-23T00:10:13Z" Destination="https://example-idp.com" AssertionConsumerServiceURL="https://example-sp.com/Acs">
<saml2:Issuer>https://example-sp.com</saml2:Issuer>
</saml2p:AuthnRequest>

The IDP says: "SignatureStatus: NOT_PRESENT". I'm guessing that means that the authnrequest should have a <ds:Signature section? If so, how do I configure Sustainsys.Saml2.AspNetCore2 to include it?

The metadata xml I received from the idp contains a <ds:Signature section, but looking at the source code for Sustainsys.Saml2.AspNetCore2, it looks like that part of the metadata gets ignored when deserializing?

I'm not very familiar with the internals of SAML, so sorry if this is a silly question.

Solution

  • You'll want to generate a self-signed .pfx file that contains both your public cert and private key. We use azure key vault, but you could also use openssl. Lots of resources that explain how to generate one of those and load it into a c# X509Certificate2 instance.

    Once you have an instance of X509Certificate2, set options.SPOptions.AuthenticateRequestSigningBehavior = Sustainsys.Saml2.Configuration.SigningBehavior.IfIdpWantAuthnRequestsSigned;

    And set IdentityProvider.WantAuthnRequestsSigned = true.

    And then add the X509Certificate2 instance like so: options.SPOptions.ServiceCertificates.Add(myX509Certificate2);

    Then run your app and start the SAML SSO process. You can use hookbin or the like to see what it sends in the AuthnRequest for SAMLRequest. You can extract the xml from that by url decoding it and then base64 decoding it like so in javascript, for instance to confirm signature xml is set and correct: atob(decodeURIComponent(samlRequestValue))