Improve security further

Docker_Registry_Install_Guide.md

@@ -81,7 +81,7 @@ sudo loginctl enable-linger CI_SERVICE_USER
 # Create Podman rootless directories outside home
 sudo mkdir -p /var/tmp/podman-$(id -u CI_SERVICE_USER)/{root,run,tmp,xdg-data,xdg-config}
 sudo chown -R CI_SERVICE_USER:CI_SERVICE_USER /var/tmp/podman-$(id -u CI_SERVICE_USER)
-sudo chmod 755 /var/tmp/podman-$(id -u CI_SERVICE_USER)
+sudo chmod 750 /var/tmp/podman-$(id -u CI_SERVICE_USER)
 
 # Initialize Podman with rootless configuration (no home directory access)
 sudo su - CI_SERVICE_USER -c "env PODMAN_ROOT=/var/tmp/podman-\$(id -u)/root PODMAN_RUNROOT=/run/user/\$(id -u)/podman-run PODMAN_TMPDIR=/var/tmp/podman-\$(id -u)/tmp XDG_DATA_HOME=/var/tmp/podman-\$(id -u)/xdg-data XDG_CONFIG_HOME=/var/tmp/podman-\$(id -u)/xdg-config podman system migrate"
@@ -137,6 +137,8 @@ ExecStart=/usr/bin/podman --root=${PODMAN_ROOT} --runroot=${PODMAN_RUNROOT} --tm
   docker.io/library/registry@sha256:8be26f81ffea54106bae012c6f349df70f4d5e7e2ec01b143c46e2c03b9e551d
 ExecStop=/usr/bin/podman --root=${PODMAN_ROOT} --runroot=${PODMAN_RUNROOT} --tmpdir=${PODMAN_TMPDIR} stop -t 10 registry
 Restart=on-failure
+MemoryMax=1G
+CPUQuota=100%
 
 [Install]
 WantedBy=default.target
@@ -156,6 +158,10 @@ Wants=network-online.target
 [Service]
 User=registry-proxy
 Group=registry-proxy
+UMask=0077
+RuntimeDirectory=registry-proxy
+LogsDirectory=registry-proxy
+ReadWritePaths=/run/registry-proxy /var/log/registry-proxy
 AmbientCapabilities=CAP_NET_BIND_SERVICE
 CapabilityBoundingSet=CAP_NET_BIND_SERVICE
 NoNewPrivileges=yes
@@ -165,6 +171,8 @@ ProtectHome=yes
 ProtectKernelTunables=yes
 ProtectKernelModules=yes
 ProtectControlGroups=yes
+ProtectClock=yes
+ProtectHostname=yes
 LockPersonality=yes
 MemoryDenyWriteExecute=yes
 RestrictAddressFamilies=AF_UNIX AF_INET AF_INET6
@@ -185,12 +193,21 @@ EOF
 sudo tee /etc/registry/nginx.conf > /dev/null << 'EOF'
 worker_processes auto;
 events { worker_connections 1024; }
+
+pid /run/registry-proxy/nginx.pid;
+access_log /var/log/registry-proxy/access.log;
+error_log  /var/log/registry-proxy/error.log;
+
 http {
   limit_req_zone $binary_remote_addr zone=reg_read:10m rate=10r/s;
   limit_req_zone $binary_remote_addr zone=reg_write:10m rate=5r/s;
   client_max_body_size 2g;
+  ssl_ciphers HIGH:!aNULL:!MD5;
+  ssl_prefer_server_ciphers on;
   proxy_http_version 1.1;
   proxy_set_header Connection "";
+  proxy_request_buffering off;
+  proxy_read_timeout 300s;
   upstream reg { server 127.0.0.1:5000; }
 
   # 443: unauthenticated pulls only
@@ -329,9 +346,19 @@ sudo update-ca-certificates
 ### 4.1 Configure Firewall
 
 ```bash
-# Configure firewall for Docker Registry v2 ports
-sudo ufw allow 443/tcp  # Docker Registry via nginx (unauthenticated pulls)
-sudo ufw allow 4443/tcp # Docker Registry via nginx (authenticated pushes with mTLS)
+# Open port 443 for unauthenticated pulls (public access)
+sudo ufw allow 443/tcp
+
+# Open port 4443 for authenticated pushes (restrict to known CIDRs)
+# Example: restrict to specific networks (adjust CIDRs as needed)
+sudo ufw delete allow 4443/tcp || true
+sudo ufw allow from 10.0.0.0/8 to any port 4443 proto tcp
+sudo ufw allow from 172.16.0.0/12 to any port 4443 proto tcp
+sudo ufw allow from 192.168.0.0/16 to any port 4443 proto tcp
+
+# For public access to 4443 (less secure), use:
+# sudo ufw allow 4443/tcp
+
 # Note: Port 5000 is NOT opened - registry runs loopback-only
 ```
 
@@ -361,6 +388,24 @@ sudo su - CI_SERVICE_USER -c "env PODMAN_ROOT=/var/tmp/podman-\$(id -u)/root POD
 # Check nginx proxy logs
 sudo journalctl -u registry-proxy.service -f --no-pager -n 50
 
+# Quick validation of hardening
+echo "=== Proxy Runtime & Logs ==="
+systemctl status registry-proxy.service
+ls -ld /run/registry-proxy /var/log/registry-proxy
+
+echo "=== Nginx Logs ==="
+tail -n1 /var/log/registry-proxy/error.log /var/log/registry-proxy/access.log
+
+echo "=== Port Bindings ==="
+ss -ltnp | egrep ':(443|4443)'; ss -ltnp | grep '127.0.0.1:5000'
+
+echo "=== Security Tests ==="
+# 443 forbids writes
+curl -k -X PUT https://YOUR_ACTUAL_IP_ADDRESS/v2/ -I | grep 403 || echo "WARNING: 443 allows writes"
+
+# 4443 requires client cert
+curl -kI https://YOUR_ACTUAL_IP_ADDRESS:4443/v2/ | egrep '400|401|403' || echo "WARNING: 4443 may not require auth"
+
 # Verify Podman is using non-home paths
 sudo su - CI_SERVICE_USER -c "env PODMAN_ROOT=/var/tmp/podman-\$(id -u)/root PODMAN_RUNROOT=/run/user/\$(id -u)/podman-run PODMAN_TMPDIR=/var/tmp/podman-\$(id -u)/tmp XDG_DATA_HOME=/var/tmp/podman-\$(id -u)/xdg-data XDG_CONFIG_HOME=/var/tmp/podman-\$(id -u)/xdg-config podman info --format '{{.Store.GraphRoot}} {{.Store.RunRoot}}'"
 ```