Re: [exim] DKIM signing & max line length

Quoting Jeremy Harris (jgh@???):

> > I tried to get some info on this. Aparently RFC2822 specifies a line
> > in an email should not exceed 998 chars (+CRLF=1000). I haven't
> > heard of any MTA enforcing this and it would seem a bit low to me.
> The current configure.default in the source code enforces it.. but you
> didn't give a version of Exim or say if you're using that
> configuration unmodified.

I'm running 4.86.2 from Ubuntu repositories but with my own
configuration. That means i have my own exim4.conf.
No split config update-conf-d-exim4.conf-conf-tomfoolery.


> > Why are there three different(!) MAX-settings in the Exim code?
> You haven't pointed them out...

I haven't checked the exact cases where this is tested in the code
but what was found in the post from 2012 still seems to linger
around in the code:

./src/demime.h:#define MIME_SANITY_MAX_LINE_LENGTH 131071
./src/mime.h:#define MIME_MAX_LINE_LENGTH 32768
./src/pdkim/pdkim.c:#define PDKIM_MAX_BODY_LINE_LEN 16384


> > Why exactly can't it DKIM sign such messages?
> This will depend on the version of Exim;
> the DKIM code has been massaged recently.

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?

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


Thanks,
-Sndr.
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