It was my understanding that when you have an Stunnel Server configured with 'verify=2', that the client that connects must have a certificate signed by the same CA/SubCA combination that the server does. So for example:
- My_Root_Ca (private CA) - Some_Random_Cert.pem - Stunnel_Sub_Ca: - Server.pem - Client.pem - Postgres_Sub_Ca: - Server.pem - postgres_user.pem
With the above structure in place (and the stunnel server using Stunnel_Sub_Ca/Server.pem) if someone tried to connect in with the Stunnel_Sub_Ca/Client.pem cert, it would work... but if they tried to connect in with Postgres_Sub_Ca/Server.pem, it wouldn't.
Unfortunately we're not seeing that behavior... we're seeing a behavior where *every* cert signed by the overall Root CA is validated. We're able to connect in using Some_Random_Cert.pem, Postgres_Sub_Ca/Server.pem and Postgres_Sub_Ca/postgres_user.pem.
This feels wrong ... what am I missing?
(We're using Stunnel 4.55 btw)
Matt Wise Sr. Systems Architect Nextdoor.com