[ietf-dkim] Re: LWSP in base64-encoded public key TXT RR

[Frank Ellermann]

Mark Martinec wrote:

> a public key in TXT RR like the following would be alright:

>   k=rsa; p=MIGfMA0GCSq<CR><LF><SP>GSIb3DQEBAQUA...

> while the one without a <SP> would not be syntactically correct:

>   k=rsa; p=MIGfMA0GCSq<CR><LF>GSIb3DQEBAQUA...

> It seems the requirement to insist on LWSP (e.g. a WSP must
> follow CRLF) in a non- message header context is very much
> artificial and unwarranted.

The ABNF also uses [FWS] with a very similar effect.  The main
difference between [FWS] and LWSP is that the latter allows
"folded" lines consisting only of trailing white space:

"A" [FWS] "B" allows AB, A<WSP>B, A<CRLF><WSP>B, etc.  But you
would need <obs-FWS> to match any A<CRLF><WSP><CRLF><WSP>B

"A" LWSP "B" has this ugly <obs-FWS> feature.  It's a clear
MUST NOT for RFC 2822 generators.  The DKIM base RFC uses a
clean <FWS> without <obs-FWS>, see (2.3)

But it also uses the 4234 <LWSP> in (2.4), sigh.  It's IMO a
bit late to address your concern, but maybe Eric could still
do a s/LWSP/[FWS]/g in AUTH48 eliminating LWSP everywhere (?)

Frank