nginx-stream.conf.j2

# This 'stream' configuration file terminates TLS and forwards the plain TCP stream to the restund process.

upstream restund {
    least_conn;
    zone backend 64k;
    server {{ hostvars[inventory_hostname]['ansible_' + restund_network_interface].ipv4.address }}:{{ restund_tcp_listen_port }} weight=1 max_fails=1 fail_timeout=10s;
}

# see also https://docs.nginx.com/nginx/admin-guide/security-controls/terminating-ssl-tcp/
server {
    listen {{ restund_tls_listen_port }} ssl;
    proxy_pass restund;
    proxy_timeout 3s;
    proxy_connect_timeout 1s;
    proxy_protocol off;
    ssl_certificate /etc/letsencrypt/live/{{ certbot_domain }}/fullchain.pem;
    ssl_certificate_key /etc/letsencrypt/live/{{ certbot_domain }}/privkey.pem;

    # intermediate configuration as per https://ssl-config.mozilla.org/#server=nginx
    ssl_session_timeout 1d;
    ssl_session_cache shared:MozSSL:10m;  # about 40000 sessions
    ssl_session_tickets off;

    # NOTE: These cipher suites are compliant to TR-02102-2. If you need to override them, please open a PR to introduce this functionality.
    # For TR-02102-2 see https://www.bsi.bund.de/SharedDocs/Downloads/EN/BSI/Publications/TechGuidelines/TG02102/BSI-TR-02102-2.html
    # As a Wire employee, for Wire-internal discussions and context see
    # * https://wearezeta.atlassian.net/browse/FS-33
    # * https://wearezeta.atlassian.net/browse/FS-444
    ssl_protocols TLSv1.2 TLSv1.3;
    ssl_ciphers ECDHE-ECDSA-AES256-GCM-SHA384:ECDHE-RSA-AES256-GCM-SHA384:ECDHE-ECDSA-AES128-GCM-SHA256:ECDHE-RSA-AES128-GCM-SHA256;
    ssl_prefer_server_ciphers off;

    # NOTE TLS context:
    # The restund usecase is one of allowing calls to work in
    # restricted networking setups, where UDP traffic is blocked and plain TCP
    # traffic may also be blocked. We don't rely on the transport encryption of
    # TLS, since the content is already end-to-end encrypted, and most calls
    # should go through UDP or plain TCP anyway.
    # Using TLS is a fallback mode only.
    # Improving TLS configuration/ciphers is thus likely unnecessary
}