[Dovecot] hanging imap... and users getting other users' emails!

[Josh Burley]

>>    1. Every two or three days users are unable to access their email
>>via IMAP. It seems that it's because dovecot-auth has hung. Has anyone
>>seen anything like this?
> 
> 
> Ive dont believe I've  seen this and I've had dovecot running for months
> on FreeBSD with pam authentication. Perhaps that indicates it could be a
> Fedora thing?

Yep, a strange one, eh? I wonder what kind of debugging I can do to 
figure it out. I've switched from PAM to the direct LDAP authentication, 
in an attempt to stabilize mail access.



>>    2. (the really serious one)... one of our users, "angie" has twice
>>had her Outlook download other users' email! Once as another user,
>>"helene", and just now as "mkarlin". The first time she got 800 of
>>helene's email, and just now, about 30 of mkarlin's.... from our log, I
>>noticed:
>>
>
> Never seen this either. But I use maildir, so that could be related too, I
> guess.
>

Well, it really seems like perhaps the UID's are getting confused. The 
format of the box (in my mind) should matter as much... it'd be one 
thing if Angie was just receiving her mail in a corrupt manner... but 
she's actually getting OTHER people's mail. Notice that she and mkarlin 
accessed at the exact same time, via two different methods. Sounds like 
a race condition between the two in the code? Or perhaps part of the PAM 
layer issue (I read in the docs about PAM not returning UID's?).



> 
>>Mar  2 17:27:10 core imap-login: Login: mkarlin [::ffff:128.195.131.2]
>>Mar  2 17:27:10 core imap-login: Login: mkarlin [::ffff:128.195.131.2]
>>Mar  2 17:27:11 core pop3-login: Login: angie [::ffff:68.231.223.128]
>>Mar  2 17:27:11 core imap-login: Login: mkarlin [::ffff:128.195.131.2]
>>Mar  2 17:27:11 core imap-login: Login: mkarlin [::ffff:128.195.131.2]
> 
> Thought about using a different version (newer, or even older) of dovecot
> and seeing if that makes the problem go away.
> 

As a matter of fact, I attempted to upgrade the server to the latest 
stable version last night. I had it all installed and reconfigured. When 
I fired it up I tested IMAP access with four different accounts. Three 
of the accounts were fine, but then the fourth account only showed a 
single email in the INBOX, the oldest one. It seemed that for that 
Mailbox, for some reason, it was unable to find the delimiters between 
emails (or something like that ;). As soon as I downgraded back, all 
mailboxes worked fine.

.josh