Subject: [ietf-smtp] Testing From-Munging

From: dkg <[email-masked]>
Date: Wed, 30 Mar 2022 05:02:15 +0000

Sorry for the noise.  I'm just confirming that From-munging still happens on IETF mailing lists (see https://github.com/ietf-tools/mailarch/issues/3487)

>From protonmail, this is an unsigned message.

---

From: Todd Herr <[email-masked]>
Date: Wed, 30 Mar 2022 11:18:17 -0400

On Wed, Mar 30, 2022 at 1:04 AM dkg <dkg=[email-masked]>
wrote:

> Sorry for the noise.  I'm just confirming that From-munging still happens
> on IETF mailing lists (see
> https://github.com/ietf-tools/mailarch/issues/3487)
>
My understanding has always been that the munging happens if the original
Author Domain has published a DMARC policy that isn't p=none, like
protonmail.com has done:

$ dig +short _dmarc.protonmail.com txt
"v=DMARC1; p=quarantine; fo=1; aspf=s; adkim=s;"

-- 

*Todd Herr * | Technical Director, Standards and Ecosystem
*e:* [email-masked]
*m:* 703.220.4153

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From: dkg <[email-masked]>
Date: Wed, 30 Mar 2022 16:36:15 +0000

heh -- there are multiple forms of From-munging, i guess. This test wasn't about the "From:" header field (which i think is what you're talking about). This test was about the "From " in the body of the message getting prefixed with a ">" character, which it did.

It's a relic of the old mbox format, where each message started with a line with "From ", so the message bodies that had that got a > prepended to them so that they wouldn't start a new message. This shouldn't really be happening on modern systems for new messages, though, since there are much better formats than mbox available today. (and, if you are for some reason obliged to use mbox, there are known reversible ways to from-munge, so that when messages transit through an mbox they don't come out modified.)

If you're interested in helping diagnose or fix this on IETF infrastructure, it's probably best to follow up on https://github.com/ietf-tools/mailarch/issues/3487

--dkg

Sent with [ProtonMail](https://protonmail.com/) secure email.

------- Original Message -------
On Wednesday, March 30th, 2022 at 11:18 AM, Todd Herr <todd.herr=[email-masked]> wrote:

> On Wed, Mar 30, 2022 at 1:04 AM dkg <dkg=[email-masked]> wrote:
>
> My understanding has always been that the munging happens if the original Author Domain has published a DMARC policy that isn't p=none, like protonmail.com has done:
>
> Todd Herr  | Technical Director, Standards and Ecosysteme: [email-masked]: 703.220.4153
>
> This email and all data transmitted with it contains confidential and/or proprietary information intended solely for the use of individual(s) authorized to receive it. If you are not an intended and authorized recipient you are hereby notified of any use, disclosure, copying or distribution of the information included in this transmission is prohibited and may be unlawful. Please immediately notify the sender by replying to this email and then delete it from your system.

---

From: Steffen Nurpmeso <[email-masked]>
Date: Wed, 30 Mar 2022 19:14:07 +0200

dkg wrote in
 <BM7YT092MMqf5RO5rnoXeFHzAPT3LxvRlwaIiVI9v06Wq0tc23ha8s43n3gqkBmVQPsLat9\
 1gqwJKD6QkqMfgM38xtXf4LbnTwibL1l6RRc=@protonmail.com>:
 |heh -- there are multiple forms of From-munging, i guess. This test \
 |wasn't about the "From:" header field (which i think is what you're \
 |talking about). This test was about the "From " in the body of the \
 |message getting prefixed with a ">" character, which it did.
 |
 |It's a relic of the old mbox format, where each message started with \
 |a line with "From ", so the message bodies that had that got a > prepended \
 |to them so that they wouldn't start a new message. This shouldn't really \
 |be happening on modern systems for new messages, though, since there \
 |are much better formats than mbox available today. (and, if you are \

I like it.  Note there is RFC 4155 i think it was.  Note the mail
format is standardized by POSIX (less strict than RFC).
Still it can be reduced to "\n\nFrom ".

 |for some reason obliged to use mbox, there are known reversible ways \
 |to from-munge, so that when messages transit through an mbox they don't \
 |come out modified.)

You normally use MIME.  The other MBOX things (MBOXO, MBOXRD iirc)
are very much unreliable.  And they all change the message
checksum.  But note i had to reintroduce >From for the "do _not_
use content-transfer-encoding" cases on user request.  There are
still people who do not want MIME.  Of course they cannot get
around it when they sign their messages.

 |If you're interested in helping diagnose or fix this on IETF infrastruct\
 |ure, it's probably best to follow up on https://github.com/ietf-tools/ma\
 |ilarch/issues/3487

You normally enforce a content encoding.
Doesn't mailman drive people insane by enforcing base64 encoding?
Some bell rings here.

--steffen
|
|Der Kragenbaer,                The moon bear,
|der holt sich munter           he cheerfully and one by one
|einen nach dem anderen runter  wa.ks himself off
|(By Robert Gernhardt)