Specify that the EncapsulatedContentInfo MUST be some specific value
(allocate an OID from IETF/IANA/whatever).
RFC5652 states that if the EncapsulatedContentInfo is not id-data, then the
signedAttrs MUST be present (whence solution 2 will apply).

2015-03-27 17:08 GMT+01:00 trans issue tracker <[email protected]>:

> #79: Precertificate signature must be over something other than just the
> TBSCertificate
>
>  If I understand the CMS spec correctly, then we're currently defining a
>  Precertificate to be a CMS structure that contains a TBSCertificate and a
>  signature over just that TBSCertificate.
>  That means that the components of a Precertificate can be trivially
>  rearranged into an X.509 certificate with a valid signature!
>
>  To fix this, we need to either...
>
>  1. Require the SignedData.encapContentInfo.eContent field to contain
>  "something || TBSCertificate" or "TBSCertificate || something".
>  or
>  2. Require a signed attribute to be present in
>  SignedData.signerInfos[0].signedAttrs.  This is essentially equivalent to
>  "TBSCertificate || something" in terms of what gets signed.
>
>  I think 2 is the cleaner solution, unless there's a cryptographic reason
>  to prefer "something || TBSCertificate" (e.g. to protect against chosen
>  prefix collisions?)
>
> --
> -------------------------------------+-------------------------------------
>  Reporter:                           |      Owner:  draft-ietf-trans-
>   [email protected]           |  [email protected]
>      Type:  defect                   |     Status:  new
>  Priority:  blocker                  |  Milestone:
> Component:  rfc6962-bis              |    Version:
>  Severity:  -                        |   Keywords:
> -------------------------------------+-------------------------------------
>
> Ticket URL: <http://trac.tools.ietf.org/wg/trans/trac/ticket/79>
> trans <http://tools.ietf.org/trans/>
>
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>



-- 
Erwann.
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