Re: [Technical Errata Reported] RFC5280 (6830)

This seems correct to me.

> On Feb 2, 2022, at 12:08 PM, RFC Errata System <[email protected]> wrote:
> 
> The following errata report has been submitted for RFC5280,
> "Internet X.509 Public Key Infrastructure Certificate and Certificate Revocation List (CRL) Profile".
> 
> --------------------------------------
> You may review the report below and at:
> https://www.rfc-editor.org/errata/eid6830
> 
> --------------------------------------
> Type: Technical
> Reported by: Corey Bonnell <[email protected]>
> 
> Section: Appendix A.1
> 
> Original Text
> -------------
> -- Note - upper bounds on string types, such as TeletexString, are
> -- measured in characters.  Excepting PrintableString or IA5String, a
> -- significantly greater number of octets will be required to hold
> -- such a value.  As a minimum, 16 octets, or twice the specified
> -- upper bound, whichever is the larger, should be allowed for
> -- TeletexString.  For UTF8String or UniversalString at least four
> -- times the upper bound should be allowed.
> 
> Corrected Text
> --------------
> -- Note - upper bounds on string types, such as TeletexString, are
> -- measured in characters.  Excepting PrintableString or IA5String, a
> -- significantly greater number of octets will be required to hold
> -- such a value.  As a minimum, 16 octets, or twice the specified
> -- upper bound, whichever is the larger, should be allowed for
> -- TeletexString.  For UTF8String or UniversalString, four
> -- times the upper bound should be allowed.
> 
> Notes
> -----
> "at least four times" is likely a holdover from RFC 3280, as the same text exists in that RFC. In RFC 3280, the definition of UTF-8 in UTF8String was normatively referencing RFC 2279, which allowed for a maximum of 6 octets to represent a single Unicode character in UTF-8. However, RFC 5280 was updated to normatively reference RFC 3629, which restricts the allowed set of characters in a UTF-8 string to match those allowed in UTF-16 (i.e., the BMP and 16 supplementary planes as opposed to all 32k planes). As a result, the maximum length for a single RFC 3629 UTF-8 character is 4 octets, rendering the guidance of "at least four times" wholly unnecessary; "four times" is sufficient in all cases.
> 
> Instructions:
> -------------
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> 
> --------------------------------------
> RFC5280 (draft-ietf-pkix-rfc3280bis-11)
> --------------------------------------
> Title               : Internet X.509 Public Key Infrastructure Certificate and Certificate Revocation List (CRL) Profile
> Publication Date    : May 2008
> Author(s)           : D. Cooper, S. Santesson, S. Farrell, S. Boeyen, R. Housley, W. Polk
> Category            : PROPOSED STANDARD
> Source              : Public-Key Infrastructure (X.509)
> Area                : Security
> Stream              : IETF
> Verifying Party     : IESG