thats a shame. I was hoping we could get the clarifying text into the Sept edition. Could it go in as a editors clarification if we can agree on it pretty soon?
David Erik Andersen wrote:
Hi, We have a small logistic problem. We plan to have the sixth edition out at the September meeting. There is less than three months meaning we do not have time for a Draft Technical Corrigendum ballot before then. A clarifying text will therefore be (a part of) a Corrigendum to the sixth edition, rather than being integrated into the sixth edition. Erik Andersen Andersen's L-Service Mobile: +45 20 97 14 90 e-mail: era@xxxxxxx http://www.x500.eu http://www.x500standard.com/-----Original Message----- From: x500standard-bounce@xxxxxxxxxxxxx [mailto:x500standard-bounce@xxxxxxxxxxxxx] On Behalf Of Santosh Chokhani Sent: 25. juni 2008 01:19 To: x500standard@xxxxxxxxxxxxx Cc: Carl Wallace Subject: [Spam] [x500standard] Re: Lack of clarity in X.509 Dave, I have not objection to clarifying. I will be happy to develop or review the text. BTW, on SAN, it is not required that it understand all name forms on which name constraint is imposed. That is because, if a name constraint occurred on a name form not understood, the certificate and path will already have been rejected. -----Original Message----- From: x500standard-bounce@xxxxxxxxxxxxx [mailto:x500standard-bounce@xxxxxxxxxxxxx] On Behalf Of David Chadwick Sent: Tuesday, June 24, 2008 7:03 AM To: x500standard@xxxxxxxxxxxxx Cc: Carl Wallace Subject: [x500standard] Re: Lack of clarity in X.509 Hi Santoshthankyou for responding. Whilst you have found text that applies to non-critical extensions, I dont believe there is any that applies directly to critical ones. It is always dangerous to assume firstly that people can correctly work out what the inferences are, and secondlythat they can work out the correct inferences, from a standard piece of text. Clearly browser manufacturers today cannot. Explicit statements are always preferred to implicit ones.If this list can agree amongst itself what the correct inferences are for unknown bits of critical extensions, then I would suggest a short paragraph be inserted in the standard to explicitly state these. If, as Santosh seems to be implying, there is no single correct inference, and each extension has to explicitly state it on a case by case basis, then the standards should insert a sentence along the following lines."If unknown elements appear in a recognised extension that is marked critical, then the interpretation of the known and unknown elements is extension specific and is documented in each extension".regards David Santosh Chokhani wrote:David, I found the following in X.509: "If unknown elements appear within the extension, and the extension is not marked critical, those unknown elements shall be ignored according to the rules of extensibility documented in 12.2.2 in ITU T Rec. X.519|ISO/IEC 9594-5". I would say that this implies through corollary that if there are elements that can not be processed in a critical extension, the certificate must be rejected. That said, you have to be logical about this stuff. For example, for EKU, if your EKU is present, even if you do not recognize others, you should use the certificate. The standard has specific language regarding unrecognized name formsinthe SAN extension. I would say that the guidance is incomplete. If a name form is not recognized and that name form is constrained viapriorcertificates in the certification path, you must reject thecertificate.You must be able to process all the name forms asserted in the name constraints extension. In general, I think the rule in X.509 may be generic and specificfieldshave rules except that SAN rule may be incomplete. -----Original Message----- From: x500standard-bounce@xxxxxxxxxxxxx [mailto:x500standard-bounce@xxxxxxxxxxxxx] On Behalf Of David Chadwick Sent: Monday, June 23, 2008 4:34 AM To: x500standard@xxxxxxxxxxxxx Subject: [x500standard] Lack of clarity in X.509 Dear All A colleague has been testing how various browsers behave when facedwithSSL certificates with various extensions marked critical or not-critical. He has found that the browsers behave in different ways. He says that one of the problems is that the standard is not specific enough on how the browsers should behave in all circumstances. Here is one scenario to consider. An extension is marked critical and the RP software understands the extension but only implements part ofit(say it has an OID for describing elements of it, or it is a set of choices). Does the text in X.509 say how the RP should handle this? I think not. Should the unknown parts of the extension be ignored or should the entire certificate be rejected? e.g. the extension isSubjectAlt Names and some of the names are understood and some are not. As a side issue, an RP can decide to accept any certificate,regardlessof what the CA says in the certificate (and some browsers allow theuserto do this). In this case the CA wont accept any liability and the RPisacting outside the standard. But is this stated clearly enough in the standard? regards David
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