Dovecot mail-crypt webmail can't read encrypted messages

Tue Aug 30 13:56:16 UTC 2022

That's exactly what I'm trying to do. Both userdb and passwdb are 
referring to dovecot-mysql.conf:

userdb {
     args = /etc/dovecot/dovecot-mysql.conf
     driver = sql
}
passdb {
     args = /etc/dovecot/dovecot-mysql.conf
     driver = sql
}

dovecot-mysql.conf contains the following query only:

password_query = SELECT \
   username as "user", password, \
   '%w' AS userdb_mail_crypt_private_password \
   FROM mailbox WHERE username="%u";

It was taken from you tutorial (I was following this tutorial closely): 
https://doc.dovecot.org/configuration_manual/mail_crypt_plugin/

So what am I doing wrong? :)

On 2022-08-30 16:13, Aki Tuomi wrote:
> 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