572629 - Thunderbird cuts off very long lines, but should handle them with tolerance as recommended by RFC 5322

Status: NEW

(MailNews Core :: Backend, defect)

Description

[David]

User-Agent:       Mozilla/5.0 (Windows; U; Windows NT 5.1; de; rv:1.9.1.9) Gecko/20100315 Firefox/3.5.9 (.NET CLR 3.5.30729)
Build Identifier: Mozilla/5.0 (Windows; U; Windows NT 5.1; de; rv:1.9.1.9) Gecko/20100317 Lightning/1.0b1 Thunderbird/3.0.4

I recieved a mail via POP that contains some very long lines (no line breaks). Thunderbird cuts off the lines after a certain amount of characters. The limit seems to be 1024 bytes (copied the line into a text editor and recognized that it contains exactly 1024 bytes in UTF8). If I look at the sourcecode of the mail the line is also cut off. So it seems thunderbird doesn't even receive the complete mail. If I look at the mail in my mail providers web frontend, the mail is shown correctly.

Reproducible: Didn't try

Steps to Reproduce:
1. Send mail via freemailer GMX.net with some text blocks that are converted into a very long line (probably more than 1024 bytes in UTF8)
2. Receive mail with thunderbird
3. Look at mail sourcecode
Actual Results:  
Lines are shown incomplete

Expected Results:  
Lines are shown complete

The mail has been marked by thunderbird as junk at first. I then marked it as non-junk. Don't know if this has anything to do with the problem.

Comment 1

[Joshua Cranmer [:jcranmer]]

Per RFC 2822, any message which has a line of more than 998 characters (excluding the CRLF) is quite simply illegal:

   There are two limits that this standard places on the number of
   characters in a line. Each line of characters MUST be no more than
   998 characters, and SHOULD be no more than 78 characters, excluding
   the CRLF.

This is quite clearly a bug in whichever program produced the message.

Comment 2

[Ludovic Hirlimann [:Usul]]

David what is producing the message ?

Comment 3

[William Gallafent]

Note that Section 2.1.1 of RFC 5822 (which obsoleted 2822 three years ago) states “Receiving implementations would do well to handle an arbitrarily large number of characters in a line for robustness sake.”

Thunderbird should be robust against ill-formed messages.

Comment 4

[William Gallafent]

(In reply to William Gallafent from comment #3)
> Note that Section 2.1.1 of RFC 5822

Apologies, that's RFC 5322 not 5822!

Comment 5

[Wayne Mery (:wsmwk)]

(In reply to William Gallafent from [corrected] comment #3)
> Note that Section 2.1.1 of RFC 5322 (which obsoleted 2822 three years ago)
> states “Receiving implementations would do well to handle an arbitrarily
> large number of characters in a line for robustness sake.”
> 
> Thunderbird should be robust against ill-formed messages.

confirm?

Comment 6

[Thomas D. (:thomas8)]

Assuming that TB's line-chopping behaviour is still around (didn't test), it's dataloss for ill-formed messages where RFC 5322 recommends to tolerate and handle it (per comment 3). Looks like a reasonable thing to do, and perhaps not all too hard.