[exim] Exim + courier-imap in virtual mode w/ secure filteri…

Hi folks,

I've been poking around the Net for the past couple of days and have not been
able to find a solution to an experiment I'm trying at home. I'd like to have
a setup of exim and courier-imap in 'virtual mode'. I want the user to have
some sort of filtering capability that's secure (that is a user will not be able
to affect other users' mailboxes). The way I see it, there are 3 possible
choices:

o exim filtering
o sieve filtering
o maildrop filtering

I thought I would try out maildrop first. Well, I cannot get maildrop to find
and/or open the correct maildir. I believe that the standalone maildrop doesn't
work right with virtual users when using the -d switch. So first question, can
standalone maildrop be made to work with userdb, usermysql, etc from the
courier-authlib stuff?

If the answer above is no, then my next question would be, is it possible to
setup a router/transport where I keep .forward or .procmailrc files in the
virtual user's directory and yet have this be secure? I'm afraid that since all
of the mail store is owned by a single user (user = vmail in my test case) that
it would be possible for a bad user to write an exim filter file that could harm
another user's maildir setup. Sample setup:

/home/vmail = homedir of the main virtual user.
/home/vmail/domains = this dir has a subdir for each of the virtual domains.
/home/vmail/domains/example.com/user = a user's 'main' directory
/home/vmail/domains/example.com/user/Maildir = user's maildir

I would put the .forward or .procmailrc file in
/home/vmail/domains/example.com/user. All files and dirs would be owned by the
UNIX user 'vmail'.

Any pointers are appreciated.

thanks,
mikeS

--
Michael Sprague | mfs@???
System and Network Engineering (SaNE), Inc
use STD::disclaimer;