This application requires I2C hardware access, which typically requires elevated privileges:

• The application must run as root or have appropriate I2C permissions
• Systemd service runs with restricted capabilities where possible
• See systemd service file for security hardening options

• Configuration files may contain sensitive information
• Set appropriate file permissions: chmod 600 /etc/i2c-display/config.json
• The application validates all configuration inputs
• Environment variables can override sensitive settings

If metrics are enabled:

• The metrics endpoint exposes system information
• Bind to localhost only in production: "address": "127.0.0.1:9090"
• Use firewall rules to restrict access
• Consider authentication proxy if exposing externally

• All dependencies are tracked in go.mod and go.sum
• Dependabot monitors for security updates
• Regular security scans via CodeQL and gosec in CI/CD

Please do not report security vulnerabilities through public GitHub issues.

Instead, please report them via:

1. GitHub Security Advisories (preferred)

   • Go to https://github.com/ausil/i2c-display/security/advisories
   • Click "Report a vulnerability"

2. Direct Email

   • Contact the maintainer directly
   • Include detailed information about the vulnerability

• Description of the vulnerability
• Steps to reproduce
• Potential impact
• Suggested fix (if any)
• Your contact information

• Initial Response: Within 48 hours
• Status Update: Within 7 days
• Fix Timeline: Depends on severity
  • Critical: Within 7 days
  • High: Within 14 days
  • Medium: Within 30 days
  • Low: Next release cycle

• We follow coordinated disclosure
• We will credit reporters (unless anonymity is requested)
• Security advisories will be published after fixes are released
• CVEs will be requested for significant vulnerabilities

1. Keep Updated

   # Check for updates regularly
   sudo systemctl stop i2c-display
   # Update package
   sudo systemctl start i2c-display

2. Secure Configuration

   # Set correct permissions
   sudo chmod 600 /etc/i2c-display/config.json
   sudo chown root:root /etc/i2c-display/config.json

3. Monitor Logs

   # Check for suspicious activity
   sudo journalctl -u i2c-display -f

4. Restrict Metrics Access

   {
     "metrics": {
       "enabled": true,
       "address": "127.0.0.1:9090"  // Localhost only
     }
   }

1. Input Validation

   • All configuration inputs are validated
   • Bounds checking on all array accesses
   • Safe type conversions

2. Error Handling

   • Never expose sensitive information in errors
   • Log errors with appropriate context
   • Fail securely

3. Dependencies

   • Review dependency changes
   • Keep dependencies minimal
   • Monitor security advisories

4. Code Review

   • All changes require review
   • Security-sensitive changes require thorough review
   • Automated security scanning in CI

The provided systemd service includes security hardening:

[Service]
# Restrict privileges
NoNewPrivileges=true

# Filesystem restrictions
ProtectSystem=strict
ProtectHome=true
ReadWritePaths=/dev/i2c-1
PrivateTmp=true

# Additional hardening (optional, may need adjustment)
# ProtectKernelTunables=true
# ProtectKernelModules=true
# ProtectControlGroups=true

Adjust based on your security requirements and system capabilities.

1. I2C Access Required - Application needs I2C device access
2. Root or i2c Group - Must run with appropriate permissions
3. Local System Only - Designed for local SBC use, not network exposure
4. Hardware Dependencies - Behavior depends on I2C hardware availability

• Application runs with minimum required privileges
• Configuration file permissions are restrictive (600)
• Metrics endpoint (if enabled) is localhost-only or firewalled
• Logs are monitored for anomalies
• System is kept up to date
• Only trusted displays are connected (I2C security)

• OWASP Top Ten
• CWE/SANS Top 25
• Go Security Policy

Thank you for helping keep this project secure!