Re: (Not-so) hypothetical question: What to do about NULs?

[Steffen Nurpmeso]

Ken Hornstein wrote in
 <20230219012125.2E48B1D739D@pb-smtp21.pobox.com>:
 |>Seems to me this is classifcation of attachment data, which will end up
 |>as octet-stream in that case.
 |
 |It's ... a little confusing!
 |
 |>For S-nail we more or less do what Heirloom mailx has done.
 |
 |Well, it seems that in the message lexer if you encounter a NUL you
 |just stop, from a_msg_scan():
 |
 |      cp = mslp->msl_cap->ca_arg.ca_str.s;
 |      if((c = *cp++) != '\0')
 |         break;

That seems to come from a command argument parser, not mail
content.  Ah no, no no, wrong code :)
I can assure you that the email

  From reproducible_build Wed Oct  2 01:50:07 1996
  Date: Wed, 02 Oct 1996 01:50:07 +0000
  From: ex3@am.ple
  Subject: s3
  MIME-Version: 1.0
  Content-Type: text/plain; charset=utf-8
  Content-Transfer-Encoding: quoted-printable
  Status: O

  Alo=00ha
  Boom.

is decoded (of course) and displayed with the NUL converted to the
Unicode graphical for NUL.
The same of i make it "binary" and put a real NUL in place of the
=00.

 |It does look like to me that for IMAP and POP a NUL character is handled
 |properly.  But that doesn't answer the question, what do you THINK should

Uh i really had to look and try out whether binary data on the
input side of IMAP or POP3 properly handles embedded NULs.
I would assume yes.  (More or less.)

 |happen?  Should NULs be passed through?  You basically can't use C strings
 |anywhere if you want to handle embedded NULs.

That is true.

 |>The implementation is total crap. (longjmp codebase, data leaks,
 |>blocking I/O, all that (it was).)  All of these (mailbox read,
 |>content-transfer decoding, character set conversion, .. display
 |>preparation) should be "filters" with input and output plugged together,
 |>with internal buffers as necessary.  That is the v15 MIME and I/O layer
 |>rewrite that is not happening for nine years.
 |
 |Sigh, I know the feeling :-/

A nice Sunday is also not a bad thing.
Ciao,

--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)