fix: enhance OpenVPN image security and privacy

Signed-off-by: Chris Gianelloni <[email protected]>

Author: wolf31o2

.github/workflows/publish.yml

@@ -5,6 +5,9 @@ on:
     branches: ['main']
     tags:
       - 'v*.*.*'
+  schedule:
+    # Weekly on Mondays at 00:00 UTC
+    - cron: '0 0 * * 1'
 
 concurrency: ${{ github.ref }}
 
@@ -14,6 +17,7 @@ jobs:
     permissions:
       contents: read
       packages: write
+      security-events: write
     steps:
       - uses: actions/checkout@1af3b93b6815bc44a9784bd300feb67ff0d1eeb3 # v6.0.0 https://github.com/actions/checkout/releases/tag/v6.0.0
       - name: qemu
@@ -49,6 +53,18 @@ jobs:
           platforms: linux/amd64,linux/arm64
           tags: ${{ steps.meta.outputs.tags }}
           labels: ${{ steps.meta.outputs.labels }}
+      - name: Run Trivy vulnerability scanner
+        uses: aquasecurity/trivy-action@b6643a29fecd7f34b3597bc6acb0a98b03d33ff8 # v0.33.1
+        with:
+          scan-type: 'image'
+          scan-ref: 'ghcr.io/blinklabs-io/openvpn:main'
+          format: 'sarif'
+          output: 'trivy-results.sarif'
+      - name: Upload Trivy scan results to GitHub Security tab
+        uses: github/codeql-action/upload-sarif@d3ced5c96c16c4332e2a61eb6f3649d6f1b20bb8 # v3.31.5
+        if: always()
+        with:
+          sarif_file: 'trivy-results.sarif'
       # Update Docker Hub from README
       - name: Docker Hub Description
         uses: peter-evans/dockerhub-description@1b9a80c056b620d92cedb9d9b5a223409c68ddfa # v5.0.0 https://github.com/peter-evans/dockerhub-description/releases/tag/v5.0.0

Dockerfile

@@ -1,14 +1,19 @@
-FROM ubuntu:24.04 AS base
+FROM debian:bookworm-slim AS base
 
 COPY bin/ /usr/local/bin
 
 RUN apt-get update \
  && apt-get dist-upgrade -y \
- && apt-get install -y openvpn iptables \
+# Install OpenVPN (latest 2.6.x from Debian repos; rebuild image periodically for security updates)
+ && apt-get install -y --no-install-recommends openvpn iptables \
+ && apt-get purge -y --auto-remove cron rsyslog \
+ && rm -rf /var/log/* \
  && apt-get clean \
  && rm -rf /var/lib/apt/lists/* \
  && chmod +x /usr/local/bin/*
 
+HEALTHCHECK --interval=30s --timeout=10s --start-period=5s --retries=3 CMD pgrep -f openvpn || exit 1
+
 EXPOSE 1194/udp
 
 ENTRYPOINT ["/usr/local/bin/entrypoint"]

README.md

@@ -1,6 +1,6 @@
 # docker-openvpn
 
-Simple OpenVPN image with updated version
+Simple OpenVPN image with updated version, optimized for privacy-focused VPN services.
 
 ## Using the image
 
@@ -12,3 +12,41 @@ docker run -d -n openvpn -v /path/to/openvpn.conf:/etc/openvpn/openvpn.conf ghcr
 
 The image provides for the ability to provide a custom startup script. It looks for a user script at `/usr/local/bin/entrypoint-user.sh` by default,
 but the location can be overridden with the `USER_STARTUP_SCRIPT` environment variable
+
+## Privacy and Security Recommendations
+
+For a no-log, privacy-focused setup:
+
+### OpenVPN Configuration
+Use these options in your `openvpn.conf` for strong encryption and no logging:
+```conf
+# Disable logging
+log /dev/null
+verb 0
+
+# Strong ciphers
+cipher AES-256-GCM
+auth SHA256
+tls-cipher TLS-ECDHE-RSA-WITH-AES-256-GCM-SHA384
+tls-version-min 1.2
+
+# Privilege drop
+user nobody
+group nogroup
+
+# Other privacy settings
+persist-key
+persist-tun
+```
+
+### Docker Run Options
+- Use Docker secrets for certificates/keys: `--secret mykey=/path/to/key`
+- Run with necessary capabilities only: `--cap-add=NET_ADMIN` (avoid `--privileged`)
+- For Kubernetes (Helm), use `securityContext` to limit privileges.
+
+### Maintenance
+- Rebuild images regularly to pull security updates from Debian repos.
+- Scan for vulnerabilities with tools like Trivy (automated via GitHub Actions).
+- Test for leaks using services like ipleak.net while connected.
+
+**Warning**: Running in privileged mode increases security risks—use only when necessary.

bin/entrypoint

@@ -18,6 +18,10 @@ fi
 
 if [[ $ENABLE_NAT = 1 ]]; then
 	iptables -t nat -A POSTROUTING -s ${NAT_SOURCE} -o ${NAT_DEVICE} -j MASQUERADE
+	# Basic kill switch: Drop forwarded traffic by default, allow only VPN-related
+	iptables -P FORWARD DROP
+	iptables -A FORWARD -i tun+ -o ${NAT_DEVICE} -j ACCEPT
+	iptables -A FORWARD -i ${NAT_DEVICE} -o tun+ -m conntrack --ctstate RELATED,ESTABLISHED -j ACCEPT
 fi
 
 # Execute user startup script if it exists