Add test for Duo's XML c14n issue.

tests/SAML2/AssertionTest.php

@@ -827,6 +827,26 @@ public function testVerifySignedAssertion()
         $this->assertTrue($assertion->getWasSignedAtConstruction());
     }
 
+
+    /**
+     * Make sure an assertion whose signature verifies cannot be tampered by using XML comments.
+     * @see https://duo.com/labs/psa/duo-psa-2017-003
+     */
+    public function testCommentsInSignedAssertion()
+    {
+        $doc = new \DOMDocument();
+        $doc->load(__DIR__ . '/signedassertion_with_comments.xml');
+
+        $publicKey = CertificatesMock::getPublicKeySha1();
+
+        $assertion = new Assertion($doc->firstChild);
+        $result = $assertion->validate($publicKey);
+
+        $this->assertTrue($result);
+        $this->assertEquals("_1bbcf227253269d19a689c53cdd542fe2384a9538b", $assertion->getNameId()['Value']);
+    }
+
+
     /**
      * Try to verify a signed assertion in which a byte was changed after signing.
      * Must yield a validation exception.

tests/SAML2/signedassertion_with_comments.xml

@@ -0,0 +1,5 @@
+<saml:Assertion xmlns:saml="urn:oasis:names:tc:SAML:2.0:assertion" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xs="http://www.w3.org/2001/XMLSchema" ID="_d908a49b8b63665738430d1c5b655f297b91331864" Version="2.0" IssueInstant="2016-03-11T14:53:15Z"><saml:Issuer>https://thki-sid.pt-48.utr.surfcloud.nl/ssp/saml2/idp/metadata.php</saml:Issuer><ds:Signature xmlns:ds="http://www.w3.org/2000/09/xmldsig#">
+  <ds:SignedInfo><ds:CanonicalizationMethod Algorithm="http://www.w3.org/2001/10/xml-exc-c14n#"/>
+    <ds:SignatureMethod Algorithm="http://www.w3.org/2000/09/xmldsig#rsa-sha1"/>
+  <ds:Reference URI="#_d908a49b8b63665738430d1c5b655f297b91331864"><ds:Transforms><ds:Transform Algorithm="http://www.w3.org/2000/09/xmldsig#enveloped-signature"/><ds:Transform Algorithm="http://www.w3.org/2001/10/xml-exc-c14n#"/></ds:Transforms><ds:DigestMethod Algorithm="http://www.w3.org/2000/09/xmldsig#sha1"/><ds:DigestValue>3T1G7tVq5t3vYQEHerp8sRWakxs=</ds:DigestValue></ds:Reference></ds:SignedInfo><ds:SignatureValue>pdcWOeAtYOnCAXSt/bTwtFHRM1Qk23NI85NMDXwUPpwC8RJ939fmleb3OL12LyO1lkOq7a8JRV/Qmav5CPapYMVMkNpN8Brz731rBcP9cPzcuXumP7h4m7HjxuAo4C+V6q6l981cuf/THsrX2PfG/+SFwwYzwAECb7JSHYFnoRc=</ds:SignatureValue>
+<ds:KeyInfo><ds:X509Data><ds:X509Certificate>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</ds:X509Certificate></ds:X509Data></ds:KeyInfo></ds:Signature><saml:Subject><saml:NameID SPNameQualifier="https://engine.test.surfconext.nl/authentication/sp/metadata" Format="urn:oasis:names:tc:SAML:2.0:nameid-format:transient">_1bbcf227253269d19a<!-- some random comment-->689c53cdd542fe2384a9538b</saml:NameID><saml:SubjectConfirmation Method="urn:oasis:names:tc:SAML:2.0:cm:bearer"><saml:SubjectConfirmationData NotOnOrAfter="2016-03-11T14:58:15Z" Recipient="https://engine.test.surfconext.nl/authentication/sp/consume-assertion" InResponseTo="CORTO6e667c685720477499c07c3864ac257271f1a212"/></saml:SubjectConfirmation></saml:Subject><saml:Conditions NotBefore="2016-03-11T14:52:45Z" NotOnOrAfter="2016-03-11T14:58:15Z"><saml:AudienceRestriction><saml:Audience>https://engine.test.surfconext.nl/authentication/sp/metadata</saml:Audience></saml:AudienceRestriction></saml:Conditions><saml:AuthnStatement AuthnInstant="2016-03-11T14:53:15Z" SessionNotOnOrAfter="2016-03-11T22:53:15Z" SessionIndex="_a2576e3e285e9e4d676b40b6c695b4a3cdc16ebd8b"><saml:AuthnContext><saml:AuthnContextClassRef>urn:oasis:names:tc:SAML:2.0:ac:classes:Password</saml:AuthnContextClassRef></saml:AuthnContext></saml:AuthnStatement><saml:AttributeStatement><saml:Attribute Name="urn:mace:dir:attribute-def:uid" NameFormat="urn:oasis:names:tc:SAML:2.0:attrname-format:uri"><saml:AttributeValue xsi:type="xs:string">student2</saml:AttributeValue></saml:Attribute><saml:Attribute Name="urn:mace:terena.org:attribute-def:schacHomeOrganization" NameFormat="urn:oasis:names:tc:SAML:2.0:attrname-format:uri"><saml:AttributeValue xsi:type="xs:string">university.example.org</saml:AttributeValue><saml:AttributeValue xsi:type="xs:string">bbb.cc</saml:AttributeValue></saml:Attribute><saml:Attribute Name="urn:schac:attribute-def:schacPersonalUniqueCode" NameFormat="urn:oasis:names:tc:SAML:2.0:attrname-format:uri"><saml:AttributeValue xsi:type="xs:string">urn:schac:personalUniqueCode:nl:local:uvt.nl:memberid:524020</saml:AttributeValue><saml:AttributeValue xsi:type="xs:string">urn:schac:personalUniqueCode:nl:local:surfnet.nl:studentid:12345</saml:AttributeValue></saml:Attribute><saml:Attribute Name="urn:mace:dir:attribute-def:eduPersonAffiliation" NameFormat="urn:oasis:names:tc:SAML:2.0:attrname-format:uri"><saml:AttributeValue xsi:type="xs:string">member</saml:AttributeValue><saml:AttributeValue xsi:type="xs:string">student</saml:AttributeValue></saml:Attribute></saml:AttributeStatement></saml:Assertion>