[Servercert-wg] Draft Ballot: Precertificates and OCSP

Wayne Thayer wthayer at mozilla.com
Fri Sep 20 14:05:36 MST 2019


In a discussion on the mozilla.dev.security.policy list [1], it was pointed
out that the BR requirements related to precertificates conflict with the
expectations of some browsers for valid OCSP responses to be supplied in
response to a request for a serial number in a precertificate. This ballot
is a minimal attempt to resolve the issue.

It also attempts to remove the 2013 effective dates from BR section 4.9.10.
I've restructured the language in the last two paragraphs of that section
without intending to change the meaning, but the current language is a bit
confusing.

I'll appreciate everyone's feedback on this draft ballot. I'm also looking
for two endorsers.

Thanks,

Wayne
========================

Ballot SCXX: Precertificates and OCSP

Purpose of Ballot:

This ballot intends to clarify requirements placed on precertificates in BR
section 7.1.2.5.

During a lengthy discussion on the mozilla.dev.security.policy forum [1],
it was discovered that BR section 4.9.10 combined with BR section 7.1.2.5
prevents a CA from responding “good” for a precertificate. This is a
problem because there is no guarantee that a certificate corresponding to a
precertificate has not been issued, resulting in root store policies such
as [2] that require CAs to treat the existence of a precertificate as a
presumption that a corresponding certificate has been issued and thus that
a valid OCSP response is required.

This ballot intends to resolve the problem by reducing the scope of section
7.1.2.5. This section was originally [3] intended only to address duplicate
serial numbers that would violate RFC 5280 section 4.1.2.2. In addition,
this ballot removes legacy effective dates from BR section 4.9.10.

[1]
https://groups.google.com/d/msg/mozilla.dev.security.policy/LC_y8yPDI9Q/NbOmVB77AQAJ

[2]
https://wiki.mozilla.org/CA/Required_or_Recommended_Practices#Precertificates

[3] https://cabforum.org/pipermail/public/2014-January/002694.html

The following motion has been proposed by Wayne Thayer of Mozilla and
endorsed by XXX of YYY and XXX of YYY.


-- MOTION BEGINS --

This ballot modifies the “Baseline Requirements for the Issuance and
Management of Publicly-Trusted Certificates” as follows, based on Version
1.6.6:

REPLACE section 7.1.2.5 of the Baseline Requirements in its entirety with:

7.1.2.5 Application of RFC 5280



For purposes of clarification, a Precertificate, as described in RFC 6962 –
Certificate Transparency, shall not be considered to be a “certificate”
subject to the serial number uniqueness requirements of section 4.1.2.2 of
RFC 5280 - Internet X.509 Public Key Infrastructure Certificate and
Certificate Revocation List (CRL) Profile under these Baseline Requirements.

REPLACE section 4.9.10 of the Baseline Requirements as follows:



The CA SHALL support an OCSP capability using the GET method for
Certificates issued in accordance with these Requirements.



For the status of Subscriber Certificates:

The CA SHALL update information provided via an Online Certificate Status
Protocol at least every four days. OCSP responses from this service MUST
have a maximum expiration time of ten days.

For the status of Subordinate CA Certificates:

The CA SHALL update information provided via an Online Certificate Status
Protocol at least (i) every twelve months and (ii) within 24 hours after
revoking a Subordinate CA Certificate.

If the OCSP responder receives a request for status of a certificate that
has not been issued, then the responder SHOULD NOT respond with a "good"
status. OCSP responders for CAs which are not Technically Constrained in
line with Section 7.1.5 MUST NOT respond with a "good" status for such
certificates. The CA SHOULD monitor the responder for such requests as part
of its security response procedures.

-- MOTION ENDS --


*** WARNING ***: USE AT YOUR OWN RISK.  THE REDLINE BELOW IS NOT THE
OFFICIAL VERSION OF THE CHANGES (CABF Bylaws, Section 2.4(1)):

A comparison of the changes can be found at: <TBD>
<https://github.com/wthayer/documents/compare/master...wthayer:EV-Subject-Information>

The procedure for approval of this ballot is as follows:

Discussion (7+ days)

Start Time: TBD UTC

End Time: TBD UTC

Vote for approval (7 days)

Start Time: TBD

End Time: TBD
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