Re: postfix, dovecot-lda, /run/dovecot/stats-writer socket permision and local user delivery, again

On 21/02/2022 23:24 Michael Tokarev mjt@tls.msk.ru wrote:

Hi!

There are many questions on the 'net about the same theme: lda(mjt): Error: net_connect_unix(/run/dovecot/stats-writer) failed: Permission denied

dovecot-lda is run from postfix as mailbox_command for local users.

There's even a suggestion on dovecot wiki to make dovecot-lda setgid (to mail) - for a different reason but people use this trick to shut this error message up. See eg the last message at https://forum.zentyal.org/index.php?topic=35236.0 which points to https://wiki2.dovecot.org/LDA/Postfix .

But the thing is: mail delivery stops right after making dovecot-lda setgid, like this:

Feb 22 00:06:46 tsrv dovecot: lda(mjt)<253650>:
Fatal: setresgid(914(dovecot),914(dovecot),8(mail)) failed with euid=1000(mjt):
Operation not permitted

why the hell lda tries to setuid to dovecot user? It will definitely unable to write to the maildir since it is owned by user mjt, not by user dovecot!

And I *only* made it setgid, not setuid.

How to use dovecot-lda together with postfix, after all?

Thanks,

/mjt

The most simple fix which usually works is

service stats { unix_listener stats-writer { mode = 0666 } }

Aki