Howto block nginx web site access if browsers have no ssl certificate - nginx

Question

I am a newb and i installed jupyterhub with nginx reverse proxy on my ubuntu 18.04 server. I built my own root CA and self signed certificate with openssl. Https connections works very well if my rootCA is installed on my others computers. I want to block access for the computers who don't have my rootCA.
the file /etc/nginx/nginx.conf is untouched and my config file /etc/nginx/sites-available/jupyter.conf is:
# top-level http config for websocket headers If Upgrade is defined,
# Connection = upgrade If Upgrade is empty, Connection = close
map $http_upgrade $connection_upgrade {
default upgrade;
'' close;
}
# HTTP server to redirect all 80 traffic to SSL/HTTPS
server {
listen 80;
server_name 192.168.4.70 mlserver.net localhost;
# Tell all requests to port 80 to be 302 redirected to HTTPS
return 302 https://$host$request_uri;
}
# HTTPS server to handle JupyterHub
server {
listen 443;
ssl on;
server_name 192.168.4.70 mlserver.net localhost;
ssl_certificate /etc/ssl/certs/mlserver.net.crt;
ssl_certificate_key /etc/ssl/private/mlserver.net.key;
ssl_session_timeout 1d;
ssl_session_cache shared:SSL:50m;
#ssl_stapling on;
# Managing literal requests to the JupyterHub front end
location / {
proxy_pass http://127.0.0.1:8000;
proxy_set_header X-Real-IP $remote_addr;
proxy_set_header Host $host;
proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
# websocket headers
proxy_http_version 1.1;
proxy_set_header Upgrade $http_upgrade;
proxy_set_header Connection $connection_upgrade;
proxy_set_header X-Scheme $scheme;
proxy_buffering off;
}
}
How can i edit this file to block access for computers who dont have certificate ?
What nginx directive add ?
Thanx.

Answer 1

I want to block access for the computers who don't have my rootCA.
This is not possible. The server has no information if the client has successfully validated the server certificate (i.e. clients which have the rootCA) or if a client simply skipped certificate validation (clients which don't have rootCA).
One could try to add a HSTS header so that browsers will not simply allow to ignore certificate problems. But this can also be bypassed on the client side without the server noticing, it just makes it a bit harder.
If you want to control who can access the notebook you would need proper authentication of the clients instead. Knowledge of the rootCA is not client authentication.