[Mailman-Users] Messages silently disappearing

[Harald Meland]

[Wes Morriston]

> Hi again.
> 
> I did a 
> 
>    ls -ld /home/mailman/data
> 
> and got this.
> 
>    drwxrwsr-x   2 root  mailman       512 Feb  9 17:37 data
> 
> That is exactly how mailman installed itself.  (I was root when I did
> the install.)

Analysis time:

* Mailman complains that it cannot create files in the
  /home/mailman/data directory

* /home/mailman/data directory is writable by group "mailman"

Conclusion: Mailman does not have write access where the "mailman"
group has write access.  Or your system could be seriously screwed up,
of course -- but that's not a very productive way of thinking :)

How things _should_ be working:

 * sendmail receives a message for a mailman address
 * sendmail spawns /home/mailman/mail/wrapper, and pipes the message
   into this.
 * mail/wrapper is a setgid "mailman" (or whatever) binary.  It checks
   whether it's real, pre-setgid GID is equal to the --with-mail-gid
   GID compiled into Mailman.  If the test succeed, proceed, otherwise
   log error to syslog.
 * Control is then passed on to python, everything running under the
   effective GID caused by the setgid mail/wrapper binary.
 * Only after control has been passed to python will (mail-related)
   things be written to /home/mailman/logs/*

Things to check, off the top of my head:

 * Is /home/mailman/mail/wrapper installed setgid:
     $ ls -l /home/mailman/mail/wrapper 
     -rwxr-sr-x   1 mailman  mailman     10988 Jan 28 14:19 /home/mailman/mail/wrapper
 * Is the partition you have installed Mailman on mounted with any
   funky mount(8) options, e.g. "nosuid" (On linux, mount(8) options
   are listed when doing "cat /proc/mounts")?

> The following, I discovered, does cause the messages to be delivered.
> 
>    chmod +s /usr/bin/python

Yikes!
-- 
Harald