Dovecot: auth sockets permissions

Solution 1:

Issue with auth-userdb permissions and ownership is solved like this:

service auth {
  unix_listener auth-userdb {
    mode = 0660 # socket access mode
    user = nobody # set uid to nobody
    group = nobody # set gid to nobody
  }
}

Problem with auth-worker permissions and ownership was much trickier and I've found out how to solve it only after reading sources of dovecot. Maybe there are some pages describing this issue, but I didn't find any. As I've found out auth-worker is a service and its socket permission may be set like this:

service auth-worker {
  unix_listener auth-worker {
    user = nobody # same as above, mode and group are supported too
  }
}

Solution 2:

According to error message you have wrong owner for /var/run/dovecot/ directory. Fix that and be happy.