#1111303 dovecot-core: dovecot imap attempts to rmdir the configured mail_inbox_path

Package:
dovecot-core
Source:
dovecot-core
Description:
secure POP3/IMAP server - core files
Submitter:
Andreas Feldner
Date:
2025-08-29 18:31:00 UTC
Severity:
normal
Tags:
#1111303#5
Date:
2025-08-16 15:22:22 UTC
From:
To:
Dear Maintainer,

after upgrading to trixie, I reconfigure dovecot - starting with the maintainer's
config files due to the complete change of config syntax - and got it working again
serving the existing mailboxes.

I again configured /var/mail/%{user | username} as mail_inbox_path, at a separate
location from all other mailboxes at some directory at user's home. All mailboxes
remain in mbox format as before.

When I set up a mail inbox path in shared namespace, dovecot is attempting to delete
the lexicographically first user "someotheruser" who is sharing their mailboxes,
whenever a user "someuser" with read access to that mailboxes is updating the
mailbox list:

journalctl output with mail_inbox_path setup for shared namespace
-----------------------------------------------------------------
Aug 16 16:43:59 somehost systemd[1]: Started dovecot.service - Dovecot IMAP/POP3 email server.
Aug 16 16:44:05 somehost dovecot[65636]: imap-login: Login aborted: Logged out (no auth attempts in 0 secs) (no_auth_attempts): user=<>, rip=some::ipv6, lip=some::ipv6, session=<xojHiXw8zKP95iU4WzA7U7on6//+m0as>
Aug 16 16:44:14 somehost auth[65647]: pam_unix(dovecot:auth): authentication failure; logname= uid=0 euid=0 tty=dovecot ruser=someuser rhost=some::ipv6  user=someuser
Aug 16 16:44:14 somehost dovecot[65636]: imap-login: Logged in: user=<someuser>, method=PLAIN, rip=some::ipv6, lip=some::ipv6, mpid=65651, TLS, session=<0klNinw8fJIqAgkIAbCIAAL////+ESJD>
Aug 16 16:44:14 somehost dovecot[65636]: imap(someuser)<65651><0klNinw8fJIqAgkIAbCIAAL////+ESJD>: Disconnected: Logged out in=98 out=1253 deleted=0 expunged=0 trashed=0 hdr_count=0 hdr_bytes=0 body_count=0 body_bytes=0
Aug 16 16:44:14 somehost auth[65647]: pam_unix(dovecot:auth): authentication failure; logname= uid=0 euid=0 tty=dovecot ruser=someuser rhost=some::ipv6  user=someuser
Aug 16 16:44:14 somehost dovecot[65636]: imap-login: Logged in: user=<someuser>, method=PLAIN, rip=some::ipv6, lip=some::ipv6, mpid=65656, TLS, session=<tE5Oinw8hpIqAgkIAbCIAAL////+ESJD>
Aug 16 16:44:14 somehost dovecot[65636]: imap(someuser)<65656><tE5Oinw8hpIqAgkIAbCIAAL////+ESJD>: Error: rmdir(/var/mail/someotheruser) failed: Permission denied
-----------------------------------------------------------------
(Note: the authentication failure listed here appears to come from a certain
pam module that doesn't know someuser, but is cured by another pam module
in the stack that can authenticate someuser)

This otheruser's INBOX will _not_ be displayed in the folder list for someuser,
whereas the INBOX of lexicographically following user is not attempted to rmdir,
and _do_ show up for the authorized someuser.


When, for testing purposes, I remove mail_inbox_path from the shared namespace's
configuration, obviously all otheruser's INBOX'es disappear from the folder list
of someuser. But now dovecat attempts to rmdir someuser's own inbox:

journalctl output with no mail_inbox_path configured for shared namespace,
but only for inbox namespace
----------------------------------------------------------------
Aug 16 16:34:48 mailserver systemd[1]: Started dovecot.service - Dovecot IMAP/POP3 email server.
Aug 16 16:34:48 mailserver unix_chkpwd[65322]: password check failed for user (someuser)
Aug 16 16:34:48 mailserver auth[65320]: pam_unix(dovecot:auth): authentication failure; logname= uid=0 euid=0 tty=dovecot ruser=someuser rhost=some::ipv6  user=someuser
Aug 16 16:34:48 mailserver dovecot[65315]: imap-login: Logged in: user=<someuser>, method=PLAIN, rip=some::ipv6 lip=some::ipv6, mpid=65324, TLS, session=<uViUaHw8psgqAgkIAbCIAAL////+ESJD>
Aug 16 16:34:48 mailserver dovecot[65315]: imap(someuser)<65324><uViUaHw8psgqAgkIAbCIAAL////+ESJD>: Error: rmdir(/var/mail/someuser) failed: Permission denied
----------------------------------------------------------------
In this case, however someuser's INBOX remains in the folder list.


*** Reporter, please consider answering these questions, where appropriate ***

   * What led up to the situation?
   * What exactly did you do (or not do) that was effective (or
     ineffective)?
   * What was the outcome of this action?
   * What outcome did you expect instead?

*** End of the template - remove these template lines ***

#1111303#10
Date:
2025-08-21 15:00:51 UTC
From:
To:
I haven't been able to fully replicate the configuration you're using,
so I haven't reproduced the issue you're describing.  While I continue
looking into that, could you report this problem upstream to
dovecot@dovecot.org?  It seems unlikely that the problem is Debian
specific.

noah