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  • [ANN] filter for text-only base64-encoded msgs [LINUX][FOSS]

    From Dario Niedermann@21:1/5 to Eli the Bearded on Mon Sep 30 18:16:48 2019
    Eli the Bearded <*@eli.users.panix.com> wrote:

    "You don't have permission to access /sw/archives/debbie-1.0.tbz on this server."

    I know, sorry about that. There's been a bit of a panic here about
    an apparently missing message (within an hour from release and after
    weeks of testing, mind you). So I blocked the archive. But further investigation showed that debbie had done the right thing by passing the message through, and the message wasn't even missing to begin with.

    More confident than ever in debbie's safety, the tarball is back online.

    [...]
    Your gopher software page clearly gets updated a lot less frequently
    than your web one.

    It's not a mirror. If you are referring to my 'datekit' for 4.3BSD, it's
    recent stuff.

    --
    Dario Niedermann. Also on the Internet at:

    gopher://darioniedermann.it/ <> https://www.darioniedermann.it/

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Eli the Bearded@21:1/5 to [email protected] on Mon Sep 30 16:00:56 2019
    X-ORIGINAL-NEWSGROUPS: comp.mail.misc,comp.mail.headers,comp.mail.mime

    I don't subscribe to .headers, but .mime is deader than this group.

    In comp.mail.misc, Dario Niedermann <[email protected]> wrote:
    Sometimes you'll get an email - without attachments, just text - and
    that email is base64-encoded for no good reason. Spammers have been
    known to do that in order to bypass spam filters. Mailing list soft-
    ware has been unwisely configured to send out encoded messages. Or clueless users tweaked their client the wrong way...

    The end results:

    1. any rule in your mail processing chain matching on message body
    will fail;

    2. ungreppable messages end up in your stored email.

    `debbie' was written to address this specific problem. [...]

    See <https://www.darioniedermann.it/sw/debbie.html> for more info.

    "You don't have permission to access /sw/archives/debbie-1.0.tbz on this server."

    Here's how I've been doing it for years:

    :r! cat ~/.procmail.base64
    # inline decode non-multiparts that are base64

    :0
    * ^MIME-Version: 1.0
    * ^Content-Type: *text/
    * ^Content-Transfer-Encoding:[ ]*base64
    {
    # 'b' body, 'f' filter, 'w' wait to check exit code
    :0bfw
    | /usr/local/bin/mmencode -b -u;echo

    # 'a' and also (but only if above exit code indicated success),
    # 'h' headers, 'f' filter
    :0ahf
    | formail -R Content-Transfer-Encoding X-Orig-Content-Transfer-Encoding
    }

    The mmencode program has gotten pretty obscure these days. Modern Linux
    users probably want to switch in "/usr/bin/base64 -d". mmencode has the advantage of also being able to encode/decode quoted-printable.

    gopher://darioniedermann.it/ <> https://www.darioniedermann.it/

    Your gopher software page clearly gets updated a lot less frequently
    than your web one.

    Elijah
    ------
    has another recipe file for detaching attachments

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Eli the Bearded@21:1/5 to [email protected] on Mon Sep 30 19:58:43 2019
    In comp.mail.misc, Dario Niedermann <[email protected]> wrote:
    More confident than ever in debbie's safety, the tarball is back online.

    Your Makefile didn't make debbie for me. A plain "make" stops at
    creating the debbie.c file. (/usr/bin/make on NetBSD 8.1). It looks like
    you have gmake assumptions.

    debbie.l.m4 line 87:
    if (stReg & (B64_FOUND | IS_TEXT )

    Shouldn't that be:
    if (((stReg & (B64_FOUND | IS_TEXT )) ==
    (B64_FOUND | IS_TEXT ))

    Otherwise it will attempt to decode the body if it is text OR if it is B64_FOUND. So "Content-Type: image/jpeg" gets decoded and CTE other
    than base64 gets "decoded".

    The suggested procmail recipe is saving your ass by doing the AND for
    you.

    Quoting me:
    Your gopher software page clearly gets updated a lot less frequently
    than your web one.
    It's not a mirror. If you are referring to my 'datekit' for 4.3BSD, it's recent stuff.

    The web version says newest stuff is first. The .sig implies that gopher
    is master and web is "also" -- secondary. There's no debbie in the
    gopher space version.

    --
    Dario Niedermann. Also on the Internet at:

    gopher://darioniedermann.it/ <> https://www.darioniedermann.it/

    Elijah
    ------
    reading the dot sig as having two columns

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Dario Niedermann@21:1/5 to Eli the Bearded on Tue Oct 1 01:45:34 2019
    Eli the Bearded <*@eli.users.panix.com> wrote:

    Your Makefile didn't make debbie for me. A plain "make" stops at
    creating the debbie.c file. (/usr/bin/make on NetBSD 8.1). It looks
    like you have gmake assumptions.

    Of course I do. It's made on Linux (see Subject) with the usual
    GNU toolchain.

    debbie.l.m4 line 87:
    if (stReg & (B64_FOUND | IS_TEXT )

    Shouldn't that be:
    if (((stReg & (B64_FOUND | IS_TEXT )) ==
    (B64_FOUND | IS_TEXT ))

    Otherwise it will attempt to decode the body if it is text OR if it is B64_FOUND.

    Yeah. Well spotted. I have oversimplified that expression. I've been
    working on debbie-2.0, which among several other changes, doesn't use
    that construct. It's due out very soon. In the mean time, using my
    procmail recipe will hide the bug.

    The .sig implies that gopher is master and web is "also" -- secondary.

    No, it doesn't... Just follow the link in the message body and you'll be
    fine.

    --
    Dario Niedermann. Also on the Internet at:

    gopher://darioniedermann.it/ <> https://www.darioniedermann.it/

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Eli the Bearded@21:1/5 to [email protected] on Tue Oct 1 04:10:32 2019
    In comp.mail.misc, Dario Niedermann <[email protected]> wrote:
    Eli the Bearded <*@eli.users.panix.com> wrote:
    Your Makefile didn't make debbie for me. A plain "make" stops at
    creating the debbie.c file. (/usr/bin/make on NetBSD 8.1). It looks
    like you have gmake assumptions.
    Of course I do. It's made on Linux (see Subject) with the usual
    GNU toolchain.

    1. NetBSD is also FOSS.
    2. INSTALL does not say "needs gmake", it says "needs make". I mean, you
    do call out flex instead of lex, not that it matters since it built and
    ran fine for me with lex instead of flex.
    3. And fixing your Makefile to work with non-gmake is very simple.

    --- Makefile.orig 2019-09-29 12:10:43.000000000 -0400
    +++ Makefile 2019-09-30 23:40:46.174357853 -0400
    @@ -19,10 +19,10 @@
    M4 = m4 $(M4FLAGS)
    TBL =

    -.INTERMEDIATE: debbie.c debbie.l debbie.1
    -
    all: debbie debbie.1.gz

    +.INTERMEDIATE: debbie.c debbie.l debbie.1
    +
    debbie: debbie.c

    debbie.c: debbie.l


    Yeah. Well spotted. I have oversimplified that expression. I've been
    working on debbie-2.0, which among several other changes, doesn't use
    that construct. It's due out very soon. In the mean time, using my
    procmail recipe will hide the bug.

    If you are taking requests, I'd find this program more useful if it
    could, possibly gated by command line options:

    1. Also decode quoted-printable (the easiest and least exciting ask).
    2. Correctly parse multipart/*, decoding all text/plain or text/* parts
    (more complicated).
    3. Accept command line arguments for which MIME types in multipart/* (or
    whole non-multipart messages)