Dovecot mail-crypt webmail can't read encrypted messages

Tue Aug 30 13:13:15 UTC 2022

You need to return the private password in your passdb query, like

SELECT .... '%w' AS userdb_mail_crypt_private_password ... 

not in your userdb query, as %w will not be available there.

Aki

> On 30/08/2022 15:33 EEST Serveria Support <support at serveria.com> wrote:
> 
>  
> Update: I managed to remove the master user query so users are not 
> getting marked as master_user on login. However, that doesn't seem to 
> affect anything. I'm still unable to read encoded emails in webmail. No 
> new errors are showing up in the log. I have even created a brand new 
> user and all new keys via doveadm but still no go. Any suggestions?
> 
> On 2022-08-29 16:30, Serveria Support wrote:
> > Upon closer review, it seems you're probably right: both users are in
> > fact marked master_user. How is that possible? I haven't marked new
> > user as a master_user. Are users marked master_user by default? What's
> > even more interesting, /etc/dovecot/dovecot-master-users doesn't
> > contain this user's data. Is it possible to unset this master_user
> > flag somehow? I browsed through the db in mySQL but wasn't able to
> > locate any master_users as well. Sorry for being such a noob... :)
> > 
> > On 2022-08-29 11:33, Aki Tuomi wrote:
> >> Hard to say.
> >> 
> >> If you are logging is master_user, there will be different password
> >> than normal user. Usually. With your setup, you can only access user's
> >> mail if you are using the exact same password that the user was using.
> >> 
> >> Your logs seem to indicate that you are logging as master_user, so you
> >> are probably unable to access mails.
> >> 
> >> Aki
> >> 
> >> 
> >>> On 29/08/2022 10:51 EEST Serveria Support <support at serveria.com> 
> >>> wrote:
> >>> 
> >>> 
> >>> Emm, sorry for the confusion, there are two users authenticating -
> >>> master user "postmaster" and the second user called "test". I have 
> >>> just
> >>> obfuscated users by replacing usernames with myuser. So no, this
> >>> shouldn't be the issue.
> >>> 
> >>> Any other suggestions?
> >>> 
> >>> On 2022-08-29 10:30, Aki Tuomi wrote:
> >>> >> On 29/08/2022 09:26 EEST Serveria Support <support at serveria.com>
> >>> >> wrote:
> >>> >>
> >>> >>
> >>> >> It's a testing install my main goal is to make it work. I will play
> >>> >> around with password encryption before going live.
> >>> >>
> >>> >> I have enabled all possible debugging yet I can's see the value you
> >>> >> mentioned in the log file. Could you please point me?
> >>> >>
> >>> >> Aug 29 01:46:30 mx dovecot: auth-worker(648543): Debug: conn
> >>> >> unix:auth-worker (pid=648542,uid=110): auth-worker<1>:
> >>> >> sql(myuser at mydomain.xyz,xx.xx.xx.xx,<Y+4ayVrnJ9VV/kpz>): query: SELECT
> >>> >> mailbox.password, mailbox.allow_nets FROM mailbox,domain WHERE
> >>> >> mailbox.username='myuser at mydomain.xyz' AND mailbox.`enableimaptls`=1
> >>> >> AND
> >>> >> mailbox.active=1 AND mailbox.domain=domain.domain AND
> >>> >> domain.backupmx=0
> >>> >> AND domain.active=1
> >>> >
> >>> > it's not set here.
> >>> >
> >>> >
> >>> >> Aug 29 01:46:30 mx dovecot: auth-worker(648543): Debug: conn
> >>> >> unix:auth-worker (pid=648542,uid=110): auth-worker<2>:
> >>> >> sql(myuser at mydomain.xyz,xx.xx.xx.xx,<Y+4ayVrnJ9VV/kpz>): SELECT
> >>> >> LOWER('myuser at mydomain.xyz') AS master_user,
> >>> >> LOWER(CONCAT(mailbox.storagebasedirectory, '/', mailbox.storagenode,
> >>> >> '/', mailbox.maildir)) AS home, CONCAT(mailbox.mailboxformat, ':~/',
> >>> >> mailbox.mailboxfolder) AS mail, CONCAT('*:bytes=',
> >>> >> mailbox.quota*1048576) AS quota_rule FROM mailbox,domain WHERE
> >>> >> mailbox.username='myuser at mydomain.xyz' AND mailbox.`enableimaptls`=1
> >>> >> AND
> >>> >> mailbox.active=1 AND mailbox.domain=domain.domain AND
> >>> >> domain.backupmx=0
> >>> >> AND domain.active=1
> >>> >
> >>> > it's not set here either.
> >>> >
> >>> > So. You are doing master user login, and are wondering why user's
> >>> > password is not available?
> >>> >
> >>> > Master user logins are not really compatible with using user's
> >>> > password as encryption key.
> >>> >
> >>> > Aki
> >>> >
> >>> >>
> >>> >> On 2022-08-29 07:56, Aki Tuomi wrote:
> >>> >> >> On 28/08/2022 09:20 EEST Serveria Support <support at serveria.com>
> >>> >> >> wrote:
> >>> >> >>
> >>> >> >>
> >>> >> >> I'm trying to setup Dovecot with mail-crypt plugin with per-user
> >>> >> >> encryption.
> >>> >> >>
> >>> >> >> I have configured mail-crypt plugin as per official guide here:
> >>> >> >> https://doc.dovecot.org/configuration_manual/mail_crypt_plugin/
> >>> >> >>
> >>> >> >> After that I created a user and an encrypted key by running this
> >>> >> >> command: doveadm -o \plugin/mail_crypt_private_password=12345 mailbox
> >>> >> >> cryptokey generate -u mail at example.org -URf (replacing dummy data ofc)
> >>> >> >>
> >>> >> >> I can log in to webmail (and Dovecot) just fine, emails are getting
> >>> >> >> sent
> >>> >> >> and delivered. I have also checked the storage and the messages seem
> >>> >> >> to
> >>> >> >> be stored encrypted.
> >>> >> >>
> >>> >> >> However, I can't read the emails in webmail (just headers can be seen)
> >>> >> >> and in Dovecot logs I can see the following error:
> >>> >> >>
> >>> >> >> failed: Private key not available: Cannot decrypt key ### Cannot
> >>> >> >> decrypt
> >>> >> >> key ### <8632: Password not available (FETCH RFC822.HEADER)
> >>> >> >>
> >>> >> >> There seems to be an issue with mySQL query. The query I'm using
> >>> >> >> (Select
> >>> >> >> username as "user", password,"%w" as
> >>> >> >> userdb_mail_crypt_private_password
> >>> >> >> from mailbox;) seems to work just fine, when run from mysql prompt it
> >>> >> >> outputs the usernames and passwords, but the error is still there
> >>> >> >> (Cannot decrypt key ### Password not available).
> >>> >> >>
> >>> >> >> Any ideas? What am I missing
> >>> >> >
> >>> >> > Hi!
> >>> >> >
> >>> >> > First of all, it's super-unsafe to use user's password like that as
> >>> >> > private password, at least run it through SHA256. This prevents
> >>> >> > dovecot from doing expansions on it by accident.
> >>> >> >
> >>> >> > Secondly, enable mail_debug=yes and auth_debug=yes, run it again, and
> >>> >> > make sure the correct value gets added as
> >>> >> > 'plugin/mail_crypt_private_password' when using with webmail.
> >>> >> >
> >>> >> > Aki