Re: [Ietf-dkim] Question about lone CR / LF

[John R Levine <[e-mail]>]

> I agree that by the time you're talking to a DKIM (or any) filter, I expect
> that this has been handled somehow.  CRLF ends a line, anything before that
> is part of the line, and WSP is just a space or a tab.  Past that, garbage
> in, garbage out.

Yup, which is why I'd prefer to take out the garbage.

As I'm sure you know, on Unix-ish systems the internal line separator is 
LF, so MTAs add the CR on the way out and remove it on the way in.  DKIM 
routines operate on the internal form so they have code to add a CR before 
each LF when making hashes.  So if a message shows up with bare LFs, those 
DKIM verifiers will treat it as though those were CR LF.  But if a message 
came from some other system, say Windows, that uses CR LF internally, it 
won't have added the CRs and the hashes won't match.

It seems to me that a signature that may or may not verify depending on 
internal warts of the verifier is worse than no signature at all.

Regards,
John Levine, [e-mail], Taughannock Networks, Trumansburg NY
Please consider the environment before reading this e-mail. https://jl.ly