Re: SSL between Primary and Seconday PostgreSQL DBs

Susan Joseph <sandajoseph@xxxxxxxxxxx> · Thu, 27 Aug 2020 10:57:19 +0000 (UTC)

So has no one done this before?

-----Original Message-----

From: Susan Joseph <sandajoseph@xxxxxxxxxxx>

To: pgsql-general@xxxxxxxxxxxxxx <pgsql-general@xxxxxxxxxxxxxx>

Sent: Mon, Aug 24, 2020 10:10 am

Subject: SSL between Primary and Seconday PostgreSQL DBs

 I have setup a Primary and Secondary PostgreSQL DBs.  They were setup up with basic replication then I went back and modified them to use SSL.  I am just not sure if I did it correctly.  Everything is working but I want to make sure I have the settings correctly.  I am using PostgreSQL 11.2.  

I have a PKI that I stood up so I issued 2 server certificates one for each database from my CA.
Primary server certificate - Primary Database

The FQDN and IP address are set in the SAN field.
FQDN is also the CN in the DN
Key Usage is set to Digital Signature and Key encipherment
EKU is set to Server Authentication and Client Authentication

Rep_user certificate - Secondary Database
CN is set to the rep_user account name
Key Usage is set to digital signature and key encipherment
EKU is set to client authentication

Each certificate file contains the certificate and the subCA certificate who issued the certificate and put in a file called server.crt for the Primary and client.crt for the secondary.

The key for each certificate is stored in a separate file unencrypted (I have questions about this later on) in a file called server.key and client.key

The server.crt, server.key, and root.crt are put onto the primary database server in the /data/pgsql/data location, the owner and group of these files is set to postgres
The client.crt, client.key, and root.crt are put onto the
 primary database server in the /data/pgsql/data location, the owner and
 group of these files is set to postgres
On the Primary in postgresql.conf I set:
ssl=on
ssl_ca_file='root.crt'
ssl_cert_file='server.crt'
ssl_key_file='server.key'
ssl_ciphers='HIGH:MEDIUM:+3DES:!aNULL'
On the Primary in pg_hba.conf I add a replication line:

hostssl                        replication          rep_user                  cert
On the Secondary I set the following information in the postgresql.conf to:  (DO I NEED TO DO THIS??)

ssl=on
ssl_ca_file='root.crt'
ssl_cert_file='client.crt'
ssl_cert_fkey='client.key'
ssl_ciphers='HIGH:MEDIUM:+3DES:!aNULL'
On the Secondary I edit the recovery.conf file to the following:
primary_conninfo = 'user=rep_user passfile=''/data/.pgpass'' host=<Primary DB IP>
 port=5432 sslmode=verify-ca sslcert=client.crt sslkey=client.key 
sslcompression=0 target_session_attrs=any'
On the Secondary I edit the pg_hba.conf file and change the rep_user line to:
hostssl          replication         rep_user           <primary IP>/32      cert clientcert=1
On the Secondary I move the root.crt to /data/pgsql/data/.postgresql
Then I restart the databases

My questions are:

Do I need to set the information in the Secondary postgresql.conf?  Originally I did not set this and everything worked but I saw errors in my log files that said to do SSL these needed to be set so I went back and set them.  Are there pgsql commands I can run to test that my SSL is working in both directions?

Are my pg_hba.conf files set correctly?  Is that how you get SSL "turned on" for communications between the primary and the rep_user account?
If I leave my key file encrypted then every time my databases have to be started have to enter the password.  So you can either leave the passwords unencrypted and set the permissions on the file to 0600 accessible only by postgres or you can enter the key password each time the database is started up.  As someone in the security field I have a tough time leaving the key unencrypted but as some setting up a production system that is located on a network that you can't get to without directly accessing the server I feel that is enough security that I can leave them unencrypted.  Thoughts?
Am I missing anything?  There are no videos out there that show how to stand up a 2 way SSL communication channel between the primary and secondary, or does anyone have one that they can share?

Thanks,

  Susan