Why do I get an error when I try to postmap sasl password file with postfix?

Question

I installed postfix freshly as satellite system. I need to authenticate on my mail providers smpt. There postfix needs to build a sasl database from my sasl-passwd file. But it fails to do just that. How do I fix this error (last line)?:

root@confus:/etc/postfix# echo 'smtp_sasl_auth_enable = yes' >> main.cf
root@confus:/etc/postfix# echo 'smtp_sasl_security_options = noplaintext noanonymous' >> main.cf
root@confus:/etc/postfix# echo 'smtp_sasl_password_maps = hash:/etc/postfix/sasl_passwd' >> main.cf
root@confus:/etc/postfix# ll
total 116
drwxr-xr-x   3 root   root    4096 2011-06-03 13:56 ./
drwxr-xr-x 154 root   root   12288 2011-06-03 13:33 ../
-rw-r--r--   1 root   root     318 2011-06-03 13:32 dynamicmaps.cf
-rw-r--r--   1 root   root    1562 2011-06-03 13:53 main.cf
-rw-r--r--   1 root   root    5563 2011-06-03 13:32 master.cf
-rw-r--r--   1 root   root   19509 2011-05-10 15:06 postfix-files
-rwxr-xr-x   1 root   root    8729 2011-05-10 15:06 postfix-script*
-rwxr-xr-x   1 root   root   25752 2011-05-10 15:06 post-install*
drwxr-xr-x   2 root   root    4096 2011-05-10 15:06 sasl/
-rw-------   1 confus confus    51 2011-06-03 13:56 sasl_passwd
-rw-r--r--   1 root   root      28 2011-06-03 13:43 sender_canonical
-rw-r--r--   1 root   root   12288 2011-06-03 13:47 sender_canonical.db
root@confus:/etc/postfix# postmap sasl_passwd 
postmap: fatal: open database sasl_passwd.db: Permission denied
root@confus:/etc/postfix# postmap hash:sasl_passwd 
postmap: fatal: open database sasl_passwd.db: Permission denied

inb4 'sudo': Notice the "root@confus"

Answer 1

"You need to make sure that postfix user is able to read that file. You can post the output of sudo ls -l /etc/postfix/sasl_passwd.db to get more help."

And from the comments: "Change the owner of the config directory of postfix to postfix and it works."

Source

Answer 2

Same for me, problem is worse after this

Linux ... 4.9.0-9-amd64 #1 SMP Debian 4.9.168-1+deb9u2 (2019-05-13) x86_64 GNU/Linux

to turn back:

chown root:root dynamicmaps.cf
chmod 644 dynamicmaps.cf

After trying again postmap sasl_passwd, sasl_passwd.db is created and looks OK

Answer 3

The postmap command calls a service running as the postfix user. If you want your map to be created in /etc/postfix a low-impact fix is to only change the group ownership of the directory. This solves the "ownership warning" and later issues.

chown postfix /etc/postfix
chmod g+rwx /etc/postfix

Answer 4

Usually, this fixes this problem

   cd /etc/postfix
   sudo chown -R postfix .
   sudo chgrp -R postfix .
   sudo chmod -R ugo+rwx .

Its important to also make the postfix directory writeable by the postfix user as it sometimes tries to create or replace files here (which it should probably keep somewhere else!)