All, Another suggestion came in for clarification that hasn't been raised on the list yet, so I'll try and explain the scenario here.
Normally, a CA must publish and update its CRLs until the end of the CA certificate's expiration. However, I think that some CAs partition their CRLs based on issuance time, e.g., all certificates issued during January 2021. And all of those certificates would expire after the applicable validity period. I think CAs don't continue to regenerate or reissue those types of partitioned CRLs which only contain certificates that have expired. So maybe we need to add an express exception that allows CAs to omit those obsolete CRLs from the JSON file -- as long as the JSON file contains the equivalent of a "full and complete" CRL. Thoughts? Thanks, Ben On Wed, Jan 13, 2021 at 8:57 AM Rob Stradling <r...@sectigo.com> wrote: > Hi Ben. > > > *A CA technically capable of issuing server certificates MUST ensure > that > > the CCADB field "Full CRL Issued By This CA" contains either the URL for > > the full and complete CRL or the URL for the JSON file containing all > URLs > > for CRLs that when combined are the equivalent of the full and complete > CRL* > > As a consumer of this data (crt.sh), I'd much prefer to see "Full CRL > Issued By This CA" and "the URL for the JSON file" as 2 separate fields in > the CCADB. CAs would then be expected to fill in one field or the other, > but not both. Is that possible? > > To ensure that these JSON files can be programmatically parsed, I suggest > specifying the requirement a bit more strictly. Something like this: > "...or the URL for a file that contains only a JSON Array, whose > elements are URLs of DER encoded CRLs that when combined are the equivalent > of a full and complete CRL" > > > I propose that this new CCADB field be populated in all situations where > the CA is enabled for server certificate issuance. > > Most Root Certificates are "enabled for server certificate issuance". > Obviously CAs shouldn't issue leaf certs directly from roots, but > nonetheless the technical capability does exist. However, currently CAs > can't edit Root Certificate records in the CCADB, which makes populating > these new field(s) "in all situations" rather hard. > > Since OneCRL covers revocations of intermediate certs, may I suggest that > CAs should only be required to populate these new field(s) in intermediate > certificate records (and not in root certificate records)? > > Relatedly, "A CA technically capable of...that the CCADB field" seems > wrong. CCADB "CA Owner" records don't/won't contain the new field(s). > Similar language elsewhere in the policy (section 5.3.2) says "All > certificates that are capable of being used to..." (rather than "All > CAs..."). > > Technically-constrained intermediate certs don't have to be disclosed to > CCADB, but "in all situations where the CA is enabled for server > certificate issuance" clearly includes technically-constrained > intermediates. How would a CA populate the "Full CRL Issued By This CA" > field for a technically-constrained intermediate cert that has > (legitimately) not been disclosed to CCADB? > > ------------------------------ > *From:* dev-security-policy <dev-security-policy-boun...@lists.mozilla.org> > on behalf of Ben Wilson via dev-security-policy < > dev-security-policy@lists.mozilla.org> > *Sent:* 08 January 2021 01:00 > *To:* mozilla-dev-security-policy < > mozilla-dev-security-pol...@lists.mozilla.org> > *Subject:* Policy 2.7.1: MRSP Issue #218: Clarify CRL requirements for > End Entity Certificates > > CAUTION: This email originated from outside of the organization. Do not > click links or open attachments unless you recognize the sender and know > the content is safe. > > > This is the last issue that I have marked for discussion in relation to > version 2.7.1 of the Mozilla Root Store Policy > < > https://nam04.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.mozilla.org%2Fen-US%2Fabout%2Fgovernance%2Fpolicies%2Fsecurity-group%2Fcerts%2Fpolicy%2F&data=04%7C01%7Crob%40sectigo.com%7C65685639e2bf45be5f6f08d8b370cf17%7C0e9c48946caa465d96604b6968b49fb7%7C0%7C0%7C637456644391892862%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&sdata=shOhNu8IGrT0iSSt2LY4E6LQlsr6y435Vv%2BNezNCh98%3D&reserved=0 > >. > It is identified and discussed in GitHub Issue #218 > < > https://nam04.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgithub.com%2Fmozilla%2Fpkipolicy%2Fissues%2F218&data=04%7C01%7Crob%40sectigo.com%7C65685639e2bf45be5f6f08d8b370cf17%7C0e9c48946caa465d96604b6968b49fb7%7C0%7C0%7C637456644391892862%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&sdata=Zb0abofrs3IaJzX9nkEnFf6RbyCemLYIi%2B7l4SmUz5U%3D&reserved=0> > for the MRSP. > > I will soon update everyone on the status of the other 13 discussion items > already presented, as some of them are in need of revision based on > comments received thus far. > > While subsection (b) of section 7.1.2.3 of the Baseline Requirements makes > a cRLDistributionPoint (CDP) in end entity certificates optional, Mozilla > still desires that CRL-based revocation information be available because > CRLite uses CRLs to construct its revocation filters. (Apple also uses > such CRL information in its certificate validation processes and, as I > understand, is making a similar request of CAs with respect to the new > CCADB field, discussed below.) > > While all such CRL information is needed, large CRLs are disfavored because > of the time they take to download and process. Thus, CAs shard, partition, > or "scope" their CRLs into smaller chunks. Section 5 of RFC 5280 explains, > "Each CRL has a particular scope. The CRL scope is the set of certificates > that could appear on a given CRL. … A complete CRL lists all unexpired > certificates, within its scope, that have been revoked for one of the > revocation reasons covered by the CRL scope. A *full and complete CRL* > lists all unexpired certificates issued by a CA that have been revoked for > any reason." (Emphasis added.) > > There is a new field in the CCADB for CAs to include information needed for > browsers or others to construct a "full and complete CRL", i.e. to gather > information from CAs that don't include the CRL path to their "full and > complete CRL" in end entity certificates they issue. This new CCADB field > is called "Full CRL Issued By This CA" and is located under the heading > "Pertaining to Certificates Issued by this CA." Rather than condition the > requirement that CAs fill in this information in the CCADB only when they > don't include a CDP to a full and complete CRL, I propose that this new > CCADB field be populated in all situations where the CA is enabled for > server certificate issuance. In cases where the CA shards or partitions its > CRL, the CA must provide a JSON-based list of CRLs that when combined are > the equivalent of the full and complete CRL. > > Proposed language to add to section 6 of the Mozilla Root Store Policy is > as follows: > > *CAs SHOULD place the URL for the associated CRL within the > crlDistributionPoints extension of issued certificates. A CA MAY omit the > crlDistributionPoint extension, if permitted by applicable requirements and > policies, such as the Baseline Requirements. * > > *A CA technically capable of issuing server certificates MUST ensure that > the CCADB field "Full CRL Issued By This CA" contains either the URL for > the full and complete CRL or the URL for the JSON file containing all URLs > for CRLs that when combined are the equivalent of the full and complete > CRL* > . > > > I look forward to your comments and suggestions. > > Ben > _______________________________________________ > dev-security-policy mailing list > dev-security-policy@lists.mozilla.org > > https://nam04.safelinks.protection.outlook.com/?url=https%3A%2F%2Flists.mozilla.org%2Flistinfo%2Fdev-security-policy&data=04%7C01%7Crob%40sectigo.com%7C65685639e2bf45be5f6f08d8b370cf17%7C0e9c48946caa465d96604b6968b49fb7%7C0%7C0%7C637456644391892862%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&sdata=%2B3uVDNUQ7qJ1afOf7O6zDkwVB8HrEiqrQSPdVir0A88%3D&reserved=0 > _______________________________________________ dev-security-policy mailing list dev-security-policy@lists.mozilla.org https://lists.mozilla.org/listinfo/dev-security-policy
