perl-nocem - A NoCeM-on-spool implementation for INN 2.x
NoCeM, which is pronounced No See 'Em, is a protocol enabling authenticated third-parties to issue notices which can be used to cancel unwanted articles (like spam and articles in moderated newsgroups which were not approved by their moderators). It can also be used by readers as a third-party killfile. It is intended to eventually replace the protocol for third-party cancel messages.
perl-nocem processes third-party, PGP-signed article cancellation notices. It is possible not to honour all NoCeM notices but only those which are sent by people whom you trust (that is to say if you trust the PGP key they use to sign their NoCeM notices). Indeed, it is up to you to decide whether you wish to honour their notices, depending on the criteria they use.
Processing NoCeM notices is easy to set up:
- Import the keys of the NoCeM issuers you trust in order to check the
authenticity of their notices. You can do:
gpg1 --no-default-keyring --primary-keyring <pathetc>/pgp/ncmring.gpg \ --no-options --allow-non-selfsigned-uid --no-permission-warning \ --batch --import <key-file> chmod 644 <pathetc>/pgp/ncmring.gpg
where <pathetc> is the value of the pathetc parameter set in inn.conf and <key-file> the file containing the key(s) to import. The keyring must be located in <pathetc>/pgp/ncmring.gpg; you only have to create the directory <pathetc>/pgp before using gpg (it will automatically generate the ncmring.gpg file) and make sure the news user can read this file, once generated.
As a few NoCeM issuers are still using old PGP-generated keys, you may have to use gpg1 with various legacy options in command-line (like in the example above) instead of more recent versions of gpg that no longer accept such keys.
The keys of NoCeM issuers can be found in the web site of The NoCeM Registry: <http://rosalind.home.xs4all.nl/nocemreg/nocemreg.html>. You can even download there a unique file which contains all the keys.
- Create a nocem.ctl config file in pathetc indicating the
NoCeM issuers and notices you want to follow. This permission file
contains lines like:
This will remove all articles for which the issuer (first part of the line, before the colon ":") has issued NoCeM notices corresponding to the criteria specified after the colon.
You will also find information about that on the web site of The NoCeM Registry.
- Add to the newsfeeds file an entry like this one in order to feed
perl-nocem the NoCeM notices posted to alt.nocem.misc and
nocem!\ :!*,alt.nocem.misc,news.lists.filters\ :Tc,Wf,Ap:<pathbin>/perl-nocem
with the correct path to perl-nocem, located in <pathbin>. Then, reload the newsfeeds file ("ctlinnd reload newsfeeds 'NoCeM channel feed'").
Note that you should at least carry news.lists.filters on your news server (or other newsgroups where NoCeM notices are sent) if you wish to process them.
- Everything should now work. However, do not hesitate to manually test
perl-nocem with a NoCeM notice, using:
grephistory '<Message-ID>' | perl-nocem
Indeed, perl-nocem expects tokens on its standard input, and grephistory can easily give it the token of a known article, thanks to its Message-ID.
When you have verified that everything works, you can eventually turn off regular spam cancels, if you want, not processing any longer cancels containing "cyberspam" in the Path: header (see the refusecybercancels parameter in inn.conf).
The Subject: header is not checked for the @@NCM string and there is no check for the presence of the References: header.
The Newsgroups: pseudo header is not checked, but this can be done in local_want_cancel_id().
The Hierarchies: header is ignored.
Copyright 2000 by Miquel van Smoorenburg <email@example.com>.
Copyright 2001 by Marco d'Itri <firstname.lastname@example.org>.
$Id: perl-nocem.in 10399 2020-11-12 20:24:35Z iulius $