[cabf_validation] [EXTERNAL]Re: Ballot Proposal: Validation Method in certificatePolicies

Ryan Sleevi sleevi at google.com
Mon Aug 6 08:04:52 MST 2018


It would be clearer, and easier, to use the absolute form. The relative
form is a nightmare to deal with in client software - because it's not used
in any widely used X.509 extension (AFAICT). Certainly, NSS does not
support decoding that type

Further, in ASN.1, "RELATIVE OID" is a distinct type and tag than OBJECT
IDENTIFIER (0x06 vs 0x0D). Thus the proposed language "MAY" requires a
separate ASN.1 syntax (such as a CHOICE OF) to support the optionality, and
will require updates to client software to support. This may be easier with
implicit tagging rather than explicit, to avoid parsing issues on the
unhandled relative OIDs, but... it's better to just not bother with it.

On Fri, Aug 3, 2018 at 2:42 PM Wayne Thayer via Validation <
validation at cabforum.org> wrote:

> On Fri, Aug 3, 2018 at 11:30 AM Tim Hollebeek <tim.hollebeek at digicert.com>
> wrote:
>
>> I’ll endorse.
>>
>>
>>
> >
> Thanks. Anyone else?
> >
>
>> I think you just want:
>>
>>
>>
>> BRValidationMethodSyntax ::= SEQUENCE SIZE (1..MAX) OF
>> DomainOrIpAddressValidationMethodId
>>
>> DomainOrIpAddressValidationMethodId ::= OBJECT IDENTIFIER
>>
>> I think there’s a way to express the concept that
>> DomainOrIpAddressValidationMethodId MUST be a child of { 2.23.140.1.11 }
>> via ASN.1 constraints, but I can’t do it.  It might be better anyway just
>> to be handle that constraint outside of the ASN.1.
>>
>>
>>
>> The ballot should make explicit that relative OIDs are allowed in
>> addition to absolute OIDs, and if relative forms of OIDs are used, the
>> forms MUST be relative to the prefix { 2.23.140.1.2 }.  That’ll make the
>> encoding much smaller.
>>
>>
>>
>> So maybe something like:
>>
>>
>>
>> “BRValidationMethodSyntax ::= SEQUENCE SIZE (1..MAX) OF
>> DomainOrIpAddressValidationMethodId
>>
>> DomainOrIpAddressValidationMethodId ::= OBJECT IDENTIFIER
>>
>> DomainOrIpAddressValidationMethodId OIDs MUST be a child of
>> 2.23.140.1.2.4 or 2.23.140.1.2.5, and MAY appear in relative form, relative
>> to 2.23.140.1.2.”
>>
>>
>>
> >
> Would it be better to just require the use of relative form? I think so.
> >
>
>> -Tim
>>
>>
>>
>> *From:* Validation <validation-bounces at cabforum.org> *On Behalf Of *Wayne
>> Thayer via Validation
>> *Sent:* Thursday, August 2, 2018 8:05 PM
>> *To:* CA/Browser Forum Validation WG List <validation at cabforum.org>
>> *Subject:* Re: [cabf_validation] [EXTERNAL]Re: Ballot Proposal:
>> Validation Method in certificatePolicies
>>
>>
>>
>> I've addressed all the feedback that I have received in the version of
>> the ballot below and at [1].
>>
>>
>>
>> I'm a complete rookie at ABNF and I've almost certainly botched the
>> syntax. Can someone help me get the encoding right?
>>
>>
>>
>> I'm also looking for two endorsers, and of course, any additional
>> feedback.
>>
>>
>>
>> - Wayne
>>
>>
>>
>> ==========================================================
>>
>>
>>
>> Ballot SC#: Validation Method Encoded in Certificates
>>
>> Purpose of Ballot: The methods defined in BR section 3.2.2.4 and 3.2.2.5
>> to confirm control or ownership of each domain name or IP address placed in
>> a TLS certificate have varying security properties. This ballot proposes a
>> standard format for expressing the method(s) the CA used to validate domain
>> control or ownership of the Authorization Domain Name(s) placed in a
>> certificate, and requires conforming CAs to include this information in
>> certificates issued on or after July 1, 2019. This information is useful
>> for quantification and analysis when vulnerabilities in specific methods
>> are identified, and disclosing it will benefit the PKI ecosystem. As
>> specified, this information is not useful or intended for making trust
>> decisions in user agents.
>>
>> 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 upon Version
>> 1.5.7:
>>
>> Add the following definitions to section 1.2:
>>
>> {joint‐iso‐itu‐t(2) international‐organizations(23) ca‐browser‐forum(140)
>> certificate‐policies(1) baseline‐ requirements(2)
>> domain-validation-methods(4)} (2.23.140.1.2.4).
>> {joint‐iso‐itu‐t(2) international‐organizations(23) ca‐browser‐forum(140)
>> certificate‐policies(1) baseline‐ requirements(2)
>> IP-address-validation-methods(5)} (2.23.140.1.2.5).
>>
>> Add section 7.1.2.3(g), as follows:
>>
>> This extension MUST be present and SHOULD NOT be marked critical. g.
>> cabf-BRValidationMethod (2.23.140.1.11) (required on or after April 1, 2019)
>>
>> This extension contains a list of one or more OIDs that assert every
>> distinct method performed by the CA to validate domain control or ownership
>> of each FQDN contained in the certificate's subjectAlternativeName. If an
>> FQDN has been validated using multiple methods, the CA MAY assert more than
>> one of the methods. This extension SHOULD NOT be marked critical.
>>
>> These OIDs representing validation methods SHALL be defined as follows:
>>     * 2.23.140.1.2.4. concatenated with the subsection number of section
>> 3.2.2.4 corresponding to the domain validation method that was used to
>> validate one or more subjectAlternativeNames in this certificate (e.g.
>> 2.23.140.1.2.4.2'); or,
>>
>>     * 2.23.140.1.2.5 concatenated with the subsection number of section
>> 3.2.2.5 corresponding to the IP address validation method that was used to
>> validate one or more subjectAlternativeNames in the certificate (e.g.
>> '2.23.140.1.2.5.1').
>>
>> OIDs representing validation methods MUST be encoded in this extension as
>> follows:
>>
>> cabf-BRValidationMethod OBJECT IDENTIFIER ::= { 2.23.140.1.11 }
>>
>> BRValidationMethodSyntax ::= SEQUENCE SIZE (1..MAX) OF
>> DomainOrIpAddressValidationMethodId
>>
>> DomainOrIpAddressValidationMethodId ::= OBJECT IDENTIFIER
>>
>>
>> — MOTION ENDS –
>>
>>
>>
>> [1]
>> https://github.com/cabforum/documents/compare/master...wthayer:Ballot226#diff-7f6d14a20e7f3beb696b45e1bf8196f2
>>
>>
>>
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