Ghost folders & imapd segfaults

[Andrew Morgan]

On Wed, 20 Jan 2010, Jukka Huhta wrote:

> We've had two tricky special cases of folders created by users.  The
> folder names contain an exclamation mark, which, I presume, isn't
> handled as it should be.
>
> The symptom is that the ghost folders get somehow created on a
> different host than the "real" mailbox.  That results in an annoying
> error from a quota listing script: "This mailbox hierarchy does not
> exist on a single backend server".
>
> The first one was like
>
> 	user.username1.fdasf!
>
> which equals (according to cyradm) to fdasf at user.username1 with
> permissions "anyone lrs".  I could just add deletion permission to an
> admin account and dm it.
>
> But the other one is trickier.  From mailbox list dump:
>
> user.username2   1 i16!nkpd username2   lrswipkxtecda   anyone  p
> user.username2.Drafts   1 i16!nkpd username2   lrswipkxtecda   anyone  p
> user.username2.Folder   1 i16!nkpd username2   lrswipkxtecda   anyone  p
> user.username2.Folder!  1 p01!default anyone  lrs
>
> "Folder" is a regular, working folder.  "i16" is the backend server of
> username2, "nkpd" is her partition, but p01 is a front end host, a
> proxy!  How could this happen?  Through some failed folder rename?
> How come there's "default" as partition?  I cannot reproduce this on
> purpose, but I cannot delete the "Folder! " folder (yes, there seems
> to be a space) either: imapd process segfaults when trying.  See:
>
> cyradm> lm user.username2.Folder
> user.username2.Folder (\HasNoChildren)
> cyradm> lm "user.username2.Folder! "
> @user.username2.Folder (\HasNoChildren)
> cyradm> lm " @user.username2.Folder"
> @user.username2.Folder (\HasNoChildren)
> cyradm> sam " @user.username2.Folder" admin all
> setaclmailbox: admin: lrswipkxtea:
> cyradm> lm " @user.username2.Folder"
>
> cyradm> lm " @user.username2.Folder"
> [returned to shell, cyradm dies]
>
> Maillog has this:
> Jan 20 15:58:57 pcn7 admin/master[11756]: process 9773 exited,
> signaled to death by 11
>
> And syslog:
> Jan 20 15:58:57 pcn7 kernel: imapd[9773]: segfault at 0000000000000000
> rip 00000039746796f0 rsp 00007fff0ba77da8 error 4
>
> According to gdb, imapd segfaults in strlen().  Of course I don't have
> debug symbols compiled in...
>
> Any hints?

I've seen this segfault happen to me in a similar situation where the 
mailbox was listed as created on the frontend.  Note - don't try to create 
a new top-level mailbox on a frontend server!  :)

Since it was my own fault, I just removed the offending mailbox and didn't 
worry about the segfault.

I think the question here is - does Cyrus allow a non-admin to create a 
new folder on whatever backend they want?  Only admins should be allowed 
to specify a partition.

> (I must admit that cyradm is connecting to another frontend than p01
> because I currently can't login to that one as admin without a
> service break (don't ask).)

I'm pretty sure you can only fix this by issuing "dm <folder>" on p01.

 	Andy