# CSRF Token Docker Configuration - Implementation Summary

## Overview

Successfully configured CSRF token support across all Docker deployment configurations to ensure CSRF protection works reliably with built Docker images.

## Changes Made

### 1. Troubleshooting Comments Added

All docker-compose files now include inline troubleshooting guidance:
- ✅ Step-by-step checklist for common CSRF issues
- ✅ Clear diagnostic steps
- ✅ Reference to detailed documentation
- ✅ Context-specific advice for each deployment type

**New Troubleshooting Resources:**
- `CSRF_TROUBLESHOOTING.md` - Quick reference guide with solutions
- Inline comments in all docker-compose*.yml files
- Extended troubleshooting section in env.example

### 2. Configuration Files Updated

#### `app/config.py`
- ✅ Added environment variable support for `WTF_CSRF_ENABLED`
- ✅ Added environment variable support for `WTF_CSRF_TIME_LIMIT`
- ✅ Updated `DevelopmentConfig` to allow CSRF override via environment
- **Impact**: CSRF settings can now be controlled via environment variables

```python
# Base Config
WTF_CSRF_ENABLED = os.getenv('WTF_CSRF_ENABLED', 'true').lower() == 'true'
WTF_CSRF_TIME_LIMIT = int(os.getenv('WTF_CSRF_TIME_LIMIT', 3600))

# Development Config
WTF_CSRF_ENABLED = os.getenv('WTF_CSRF_ENABLED', 'false').lower() == 'true'
```

#### `env.example`
- ✅ Fixed default `WTF_CSRF_ENABLED=true` for production
- ✅ Added comprehensive documentation about SECRET_KEY importance
- ✅ Added instructions for generating secure keys
- **Impact**: New deployments will have correct CSRF defaults

### 2. Docker Compose Files Updated

All four docker-compose files have been updated with consistent CSRF configuration:

#### `docker-compose.yml` (Local Development with PostgreSQL)
```yaml
environment:
  # IMPORTANT: Change SECRET_KEY in production! Used for sessions and CSRF tokens.
  # Generate a secure key: python -c "import secrets; print(secrets.token_hex(32))"
  - SECRET_KEY=${SECRET_KEY:-your-secret-key-change-this}
  # CSRF Protection (enabled by default for security)
  - WTF_CSRF_ENABLED=${WTF_CSRF_ENABLED:-true}
  - WTF_CSRF_TIME_LIMIT=${WTF_CSRF_TIME_LIMIT:-3600}
```

#### `docker-compose.remote.yml` (Production)
```yaml
environment:
  # IMPORTANT: Change SECRET_KEY in production! Used for sessions and CSRF tokens.
  # Generate a secure key: python -c "import secrets; print(secrets.token_hex(32))"
  # The app will refuse to start with the default key in production mode.
  - SECRET_KEY=${SECRET_KEY:-your-secret-key-change-this}
  # CSRF Protection (enabled by default for security)
  - WTF_CSRF_ENABLED=${WTF_CSRF_ENABLED:-true}
  - WTF_CSRF_TIME_LIMIT=${WTF_CSRF_TIME_LIMIT:-3600}
```

#### `docker-compose.remote-dev.yml` (Remote Development)
```yaml
environment:
  # IMPORTANT: Change SECRET_KEY in production! Used for sessions and CSRF tokens.
  # Generate a secure key: python -c "import secrets; print(secrets.token_hex(32))"
  - SECRET_KEY=${SECRET_KEY:-your-secret-key-change-this}
  # CSRF Protection (enabled by default for security)
  - WTF_CSRF_ENABLED=${WTF_CSRF_ENABLED:-true}
  - WTF_CSRF_TIME_LIMIT=${WTF_CSRF_TIME_LIMIT:-3600}
```

#### `docker-compose.local-test.yml` (Local Testing with SQLite)
```yaml
environment:
  - SECRET_KEY=${SECRET_KEY:-local-test-secret-key}
  # CSRF Protection (can be disabled for local testing)
  - WTF_CSRF_ENABLED=${WTF_CSRF_ENABLED:-false}
  - WTF_CSRF_TIME_LIMIT=${WTF_CSRF_TIME_LIMIT:-3600}
```

### 3. Documentation Created

#### `docs/CSRF_CONFIGURATION.md`
Comprehensive documentation covering:
- ✅ How CSRF tokens work
- ✅ SECRET_KEY importance and generation
- ✅ Environment variable configuration
- ✅ Docker deployment scenarios
- ✅ Troubleshooting common issues
- ✅ Security best practices
- ✅ API endpoint exemptions

## Key Improvements

### 1. SECRET_KEY Management
- **Clear warnings** added to all docker-compose files
- **Generation instructions** provided inline
- **Consistency requirement** documented
- **Production validation** already exists in `app/__init__.py` (app refuses to start with weak key)

### 2. CSRF Protection
- **Enabled by default** in production environments
- **Configurable via environment** variables
- **Proper defaults** for different deployment scenarios
- **Consistent across** all docker-compose files

### 3. Developer Experience
- **Clear inline comments** in docker-compose files
- **Comprehensive documentation** for troubleshooting
- **Environment variable examples** in env.example
- **Flexible configuration** for different use cases

## How CSRF Tokens Work in Docker

```
┌─────────────────────────────────────────────────────────┐
│ 1. User visits form page                                │
│    → App generates CSRF token using SECRET_KEY          │
│    → Token embedded in form                             │
└─────────────────────────────────────────────────────────┘
                            ↓
┌─────────────────────────────────────────────────────────┐
│ 2. User submits form                                     │
│    → Browser sends CSRF token with request              │
└─────────────────────────────────────────────────────────┘
                            ↓
┌─────────────────────────────────────────────────────────┐
│ 3. App validates token                                   │
│    → Verifies signature using same SECRET_KEY           │
│    → Checks expiration (WTF_CSRF_TIME_LIMIT)           │
│    → ✓ Valid → Process request                          │
│    → ✗ Invalid → Return 400 error                       │
└─────────────────────────────────────────────────────────┘
```

## Critical Requirements for CSRF Tokens

### ✅ Same SECRET_KEY Must Be Used
- Across container restarts
- Across multiple app replicas/containers
- Between token generation and validation

### ✅ CSRF Protection Must Be Enabled
```bash
WTF_CSRF_ENABLED=true
```

### ✅ Appropriate Timeout
```bash
WTF_CSRF_TIME_LIMIT=3600  # 1 hour default
```

### ✅ Secure Cookie Settings (Production)
```bash
SESSION_COOKIE_SECURE=true
REMEMBER_COOKIE_SECURE=true
```

## Testing the Configuration

### 1. Verify Environment Variables
```bash
docker-compose exec app env | grep -E "(SECRET_KEY|CSRF)"
```

### 2. Check CSRF Token in Forms
```bash
# View any form in the browser developer tools
# Look for: <input type="hidden" name="csrf_token" value="...">
```

### 3. Test Form Submission
- Submit a form normally → Should work
- Remove csrf_token field → Should get 400 error

### 4. Verify Logs
```bash
docker-compose logs app | grep -i csrf
```

## Production Deployment Checklist

- [ ] Generate secure SECRET_KEY: `python -c "import secrets; print(secrets.token_hex(32))"`
- [ ] Set SECRET_KEY in `.env` file or environment
- [ ] Verify `WTF_CSRF_ENABLED=true` (default)
- [ ] Enable HTTPS and set `SESSION_COOKIE_SECURE=true`
- [ ] Set `REMEMBER_COOKIE_SECURE=true`
- [ ] Test form submissions after deployment
- [ ] Monitor logs for CSRF errors

## Backward Compatibility

✅ **All changes are backward compatible**
- Default values match previous behavior
- Existing deployments continue to work
- No breaking changes to API

## Security Improvements

1. ✅ **CSRF enabled by default** in production
2. ✅ **Clear documentation** about SECRET_KEY importance
3. ✅ **Inline warnings** in configuration files
4. ✅ **Consistent configuration** across deployments
5. ✅ **Environment-based control** for flexibility

## Related Files

- `app/__init__.py` - CSRF initialization and error handling
- `app/config.py` - Configuration classes
- `env.example` - Environment variable examples with troubleshooting
- `docker-compose*.yml` - Docker deployment configurations (with inline troubleshooting)
- `docs/CSRF_CONFIGURATION.md` - Detailed documentation
- `CSRF_TROUBLESHOOTING.md` - Quick troubleshooting reference
- `CSRF_TOKEN_FIX_SUMMARY.md` - Original CSRF implementation
- `scripts/verify_csrf_config.sh` - Automated configuration checker (Linux/Mac)
- `scripts/verify_csrf_config.bat` - Automated configuration checker (Windows)

## References

- [Flask-WTF CSRF Protection](https://flask-wtf.readthedocs.io/en/stable/csrf.html)
- [OWASP CSRF Prevention](https://cheatsheetseries.owasp.org/cheatsheets/Cross-Site_Request_Forgery_Prevention_Cheat_Sheet.html)

## Conclusion

CSRF tokens are now properly configured for Docker deployments with:
- ✅ Clear documentation and warnings
- ✅ Proper defaults for all deployment scenarios
- ✅ Environment variable control
- ✅ Consistent configuration across all docker-compose files
- ✅ Security best practices enforced

The application will now properly validate CSRF tokens in Docker deployments as long as a consistent SECRET_KEY is maintained.

