Re: Is Client connections via ca.crt only possible? - Mailing list pgsql-general

From Rejo Oommen
Subject Re: Is Client connections via ca.crt only possible?
Date
Msg-id CAFiZ60hNc6=nLdWUH9W9HgeP4ZHiUEf3csCoV-w5XFdMirM77A@mail.gmail.com
Whole thread Raw
In response to Re: Is Client connections via ca.crt only possible?  (Thomas Guyot <tguyot@gmail.com>)
List pgsql-general
Thank you for the reply Thomas. I agree with you on the mutual TLS that you mentioned.

Here is what I was looking at.

The configurations at the server end will be with auth-method as md5 and auth-option as clientcert=verify-ca.

In this way, the user's password along with the valid ca should allow connections to pass. 

Regards,
Rejo



On Thu, 4 Aug 2022, 03:01 Thomas Guyot, <tguyot@gmail.com> wrote:
On 2022-08-01 04:12, Rejo Oommen wrote:
> Requirement is to use only ca.crt and connect to postgres
>
> Server.crt, Server.key and ca.crt are configured at the postgres
> server for tls connection.
>
> Connection successful while using
> psql ‘host=172.29.21.222 dbname=test user=postgres sslmode=verify-ca
> sslcert=/tmp/server.crt sslkey=/tmp/server.key sslrootcert=/tmp/ca.crt
> port=5432’
>
> For clients to connect, can they use only ca.crt and connect to the
> DB. Tried and got the below error
>
> psql ‘host=172.29.21.222 dbname=test user=postgres sslmode=verify-ca
> sslrootcert=/tmp/ca.crt port=5432’
> psql: error: connection to server at “172.29.21.222”, port 50001
> failed: FATAL:  connection requires a valid client certificate
>

Hi Rejo,

I don't think you understand fully how mutual TLS auth works. For the
client to authenticate using a certificate, it needs a valid certificate
and key too, where the certificate is signed by a CA your server trusts
(usually the same CA that signed your server cert) and with a proper
subject (that bears the certificate owner's user name, the user you will
use to grant privileges in the database). You shouldn't even need to
pass a username, it will be in the certificate.

I'm talking purely from a generic view, I'm not familiar with any of the
specifics of PostgreSQL configuration but TLS authentication requires a
secret and a CA certificate isn't secret. Your server certificate
authenticates the server, but nothing authenticates the client.

Regards,

--
Thomas

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