1486710 - New line chars are converted in binary attachment on Mac using quoted-printable encoding

Status: RESOLVED WONTFIX

(MailNews Core :: Attachments, defect)

Description

[libor.bubik]

User Agent: Mozilla/5.0 (Windows NT 6.1; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/68.0.3440.106 Safari/537.36

Steps to reproduce:

I want to open or save binary attachment sent from MS Outlook. 
Attachment is encoded with quoted-printable encoding:

Content-Type: application/octet-stream;
	name="myTalkey.mtm"
Content-Transfer-Encoding: quoted-printable
Content-Disposition: attachment;
	filename="myTalkey.mtm" 


Actual results:

Binary chars sequence 0D0A is converted to 0A, so attachment is corrupted.
It happened only on MacOS, on Windows it is ok.


Expected results:

No conversion can be in binary attachment

Comment 1

[Alfred Peters [:infofrommozilla]]

Attachment: Quoted-printable encoded MIME attachment with different line endings.

(In reply to libor.bubik from comment #0)

> I want to open or save binary attachment sent from MS Outlook. 
> Attachment is encoded with quoted-printable encoding:

It is extremely awkward to use quoted-printable for the transport of binary data.

> Binary chars sequence 0D0A is converted to 0A, so attachment is corrupted.
> It happened only on MacOS, on Windows it is ok.

This is a known problem with quoted-printable. It is even described in the corresponding standard.

| RFC 2045  Internet Message Bodies
| 6.7.  Quoted-Printable Content-Transfer-Encoding
[...]
| (4)   (Line Breaks) A line break in a text body, represented
|       as a CRLF sequence in the text canonical form, must be
|       represented by a (RFC 822) line break, which is also a
|       CRLF sequence, in the Quoted-Printable encoding.
[...]
| WARNING TO IMPLEMENTORS:  If binary data is encoded in quoted-
| printable, care must be taken to encode CR and LF characters as "=0D"
| and "=0A", respectively.  In particular, a CRLF sequence in binary
| data should be encoded as "=0D=0A".  Otherwise, if CRLF were
| represented as a hard line break, it might be incorrectly decoded on
| platforms with different line break conventions.

If done so, TB also preserves the different line endings when saving.
At least here under Windows.

> Expected results:
> 
> No conversion can be in binary attachment

For your case that would certainly make sense.

But converting line endings to local format with quoted-printable encoded text files generally cause fewer problems.

Comment 2

[Wayne Mery (:wsmwk)]

> But converting line endings to local format with quoted-printable encoded text files generally cause fewer problems.

so wontfix?

Comment 3

[Jorg K (CEST = GMT+2)]

You got my vote.