Re: [exim] DKIM signing & max line length

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Author: Jeremy Harris
Date:  
To: exim-users
Subject: Re: [exim] DKIM signing & max line length
On 04/08/16 12:36, Sander Smeenk wrote:
> Exim 4.86.2 can't (won't) sign messages with overly long lines.
> I haven't tried 4.87 vanilla. Would there be a difference?


No.

> Still don't really grasp why signing a really long line would be
> different to signing a multitude of shorter lines.


Having just gone to look at the code, DKIM requires line-aware
processing of the body being signed, to implement the requirements
on empty- and whitespace-only- lines. The implementation currently
implements this by buffering a full line.

Handling arbitrary-length lines would need adding an extra state
in, to track being partway through a line. Apart from changing
some debug output, it looks feasible.
--
Cheers,
Jeremy