It looks like there may be a major bug in the new virtualmin-base package! Immediately after updating this package on my CentOS 4.2 system this morning, all mail is being delivered to my users with ownership set to root:mail instead of username:domainname. Consequently, they are unable to access any of their new messages! New mail just shows up as blank message entries in their mail clients, and the maillog indicates "failed: Permission denied" upon every pop3 open() request.
Apparently, the virtualmin-base package includes only one updated file:
-rwsr-sr-x 1 root root 4991 Jan 15 23:44 /usr/bin/procmail-wrapper*
Since all mail is delivered using this wrapper, which is setuid and setgid, this appears to be the culprit. If so, please fix this as soon as possible! I have many upset users that can't read their e-mail today!
In the meantime, it looks like I will have to reset permissions for each of these messages by hand, or come up with a quick script to take care of this.