- From: Meiko Jensen <Meiko.Jensen@ruhr-uni-bochum.de>
- Date: 11 May 2010 17:46:14 +0200
- To: "XMLSec WG Public List" <public-xmlsec@w3.org>
Within the discussion on the XPath referencing style I remembered an issue we came across lately: If an XPath contains syntactical errors, this does not result in a visible error. It is only treated differently, and might just result in referencing no node in the actual XML document. If that is not considered as an error in the XML Signature specification, there is a threat of someone screwing it up without noticing. Even the verifier does not notice: nothing was referenced, so the digest is calculated about the empty nodeset, hence about "". As this was exactly the same input as at the signer side, hash values match => signature is valid. However, it protects nothing in the document from modification. Hence, I recommend putting a sentence to XML Signature 2.0 stating that a reference to an empty nodeset MUST be treated as a fault. best regards Meiko -- Dipl.-Inf. Meiko Jensen Chair for Network and Data Security Horst Görtz Institute for IT-Security Ruhr University Bochum, Germany _____________________________ Universitätsstr. 150, Geb. IC 4/150 D-44780 Bochum, Germany Phone: +49 (0) 234 / 32-26796 Telefax: +49 (0) 234 / 32-14347 http:// www.nds.rub.de
Received on Tuesday, 11 May 2010 15:46:39 UTC