paths and permissions

[Bob George]

Greg McCann <greg at cambria.com> wrote:
> [...]
> Obviously, if a non-root user can run commands as root by
> placing them in his .procmailrc, this is a Bad Thing.

Procmail here (debian linux) is suid/sgid:

$ ls -l /usr/bin/procmail
-rwsr-sr-x    1 root     mail          66K Jan 20 12:09 /usr/bin/procmail

When first run, procmail runs as effectively user root, group mail. To address
this concern, procmail provides:

       DROPPRIVS   If  set to `yes' procmail will drop all privileges it might
                   have had (suid or sgid).  This is only useful if  you  want
                   to  guarantee  that  the bottom half of the /etc/procmailrc
                   file is executed on behalf of the recipient.

If added to /etc/procmailrc, it prevents the behavior you're concerned about.
At least I think I've got that all right! :)

- Bob