Hi, I was looking at private CAs since I don’t want to pay for a domain to use in my homelab.

What is everyone using for their private CA? I’ve been looking at plain OpenSSL with some automation scripts but would like more ideas. Also, if you have multiple reverse-proxy instances, how do you distribute domain-specific signed certificates to them? I’m not planning to use a wildcard, and would like to rotate certificates often.

Thanks!

Edit: thank you for everyone who commented! I would like to say that I recognise the technical difficulty in getting such a setup working compared to a simple certbot setup to Let’s Encrypt, but it’s a personal choice that I have made.

    • MigratingtoLemmy@lemmy.worldOPEnglish
      2·
      7 months ago

      Thanks, could you tell me why one would run this over plain OpenSSL with automation? Also, what risks would I run running a private CA? I’d love to know!

      • TCB13@lemmy.worldEnglish
        2·
        7 months ago

        could you tell me why one would run this over plain OpenSSL with automation?

        Those projects essentially are the automation…

        what risks would I run running a private CA? I’d love to know!

        https://security.stackexchange.com/questions/205174/what-are-the-risks-of-installing-a-ca-on-the-same-machine-as-openvpn-server

        More or less you’re adding a root certificate to your systems that will effectively accept any certificate issues with your CA’s key. If your PK gets stolen somehow and you don’t notice it, someone might be issuing certificates that are valid for those machines. Also real CA’s also have ways to revoke certificates that are checked by browsers (OCSP and CRLs), they may employ other techniques such as cross signing and chains of trust. All those make it so a compromised certificate is revoked and not trusted by anyone after the fact.

        • MigratingtoLemmy@lemmy.worldOPEnglish
          1·
          7 months ago

          I do realise the security problem in keeping the private key safe. I plan to use a VM with encrypted storage underneath. Do you think that’s OK for a homelab, or should I invest time into integrating HSM modules from Nitrokey?

            • MigratingtoLemmy@lemmy.worldOPEnglish
              1·
              7 months ago

              I would not like to use a public domain for my internal network. By extension, I do not want any public CA to know the domains and subdomains I use in my lab and home network

              • TCB13@lemmy.worldEnglish
                1·
                7 months ago

                Okay that’s fair but if your only concern is about “I do not want any public CA to know the domains and subdomains I use” you get around that.

                Let’s Encrypt now allows for wildcard so you can probably do something like *.network.example.org and have an SSL certificate that will cover any subdomain under network.example.org (eg. host1.network.example.org). Or even better, get a wildcard like *.example.org and you’ll be done for everything.

                I’m just suggesting this alternative because it would make your life way easier and potentially more secure without actually revealing internal subdomains to the CA.

                Another option is to just issue certificates without a CA and accept them one at the time on each device. This won’t expose you to a possibly stolen CA PK and you’ll get notified if previously the accepted certificate of some host changes.

                openssl req -x509 -nodes -newkey rsa:2048 \
-subj "/CN=$DOMAIN_BASE/O=$ORG_NAME/OU=$ORG_UNIT_NAME/C=$COUNTRY" \
-keyout $DOMAIN_BASE.key -out $DOMAIN_BASE.crt -days $OPT_days "${ALT_NAMES[@]}"