# SSL/TLS Certificate Management

## Overview

Changemaker Lite V2 supports multiple SSL/TLS certificate sources for HTTPS deployment:

- **Let's Encrypt**: Free automated certificates (recommended for self-hosted)
- **Cloudflare Origin Certificates**: Static 15-year certificates (if using Cloudflare)
- **Pangolin Tunnel SSL**: Tunnel provider handles SSL termination

**Recommendation**: Use Pangolin tunnel for simplest setup (SSL handled by tunnel provider).

---

## Certificate Sources

### Let's Encrypt with Certbot

**Best for**: Self-hosted deployments with public DNS

**Process**:
1. Install Certbot
2. Generate certificate (DNS or HTTP challenge)
3. Configure Nginx
4. Auto-renewal via cron

**Installation** (Ubuntu/Debian):
```bash
sudo apt update
sudo apt install certbot python3-certbot-nginx
```

**Generate Certificate** (HTTP-01 challenge):
```bash
# Stop Nginx temporarily
docker compose stop nginx

# Generate cert
sudo certbot certonly --standalone \
  -d cmlite.org \
  -d "*.cmlite.org" \
  --email admin@cmlite.org \
  --agree-tos \
  --non-interactive

# Start Nginx
docker compose start nginx
```

**Certificate Location**:
```
/etc/letsencrypt/live/cmlite.org/
├─ fullchain.pem  (certificate + intermediate)
├─ privkey.pem    (private key)
└─ chain.pem      (intermediate only)
```

**Nginx Configuration**:
```nginx
server {
    listen 443 ssl http2;
    server_name api.cmlite.org;

    ssl_certificate /etc/letsencrypt/live/cmlite.org/fullchain.pem;
    ssl_certificate_key /etc/letsencrypt/live/cmlite.org/privkey.pem;

    ssl_protocols TLSv1.2 TLSv1.3;
    ssl_ciphers 'ECDHE-ECDSA-AES128-GCM-SHA256:ECDHE-RSA-AES128-GCM-SHA256';
    ssl_prefer_server_ciphers on;

    # ... locations
}
```

**HTTP Redirect**:
```nginx
server {
    listen 80;
    server_name api.cmlite.org;
    return 301 https://$host$request_uri;
}
```

---

### Cloudflare Origin Certificates

**Best for**: Sites using Cloudflare DNS + proxy

**Process**:
1. Generate certificate in Cloudflare dashboard
2. Download certificate + private key
3. Install in Nginx
4. Set SSL mode to "Full (strict)"

**Generate Certificate**:
1. Cloudflare dashboard → SSL/TLS → Origin Server
2. Click "Create Certificate"
3. Hostnames: `cmlite.org`, `*.cmlite.org`
4. Validity: 15 years
5. Download certificate + private key

**Install Certificate**:
```bash
# Create directory
sudo mkdir -p /etc/ssl/cloudflare

# Save files
sudo nano /etc/ssl/cloudflare/cmlite.org.pem      # Certificate
sudo nano /etc/ssl/cloudflare/cmlite.org.key      # Private key

# Set permissions
sudo chmod 600 /etc/ssl/cloudflare/cmlite.org.key
```

**Nginx Configuration**:
```nginx
server {
    listen 443 ssl http2;
    server_name api.cmlite.org;

    ssl_certificate /etc/ssl/cloudflare/cmlite.org.pem;
    ssl_certificate_key /etc/ssl/cloudflare/cmlite.org.key;

    # ... TLS config
}
```

**Cloudflare SSL Mode**: Set to "Full (strict)" (not "Flexible").

---

### Pangolin Tunnel SSL

**Best for**: Quick deployment without SSL management

**How it works**:
1. Pangolin tunnel terminates SSL at tunnel endpoint
2. Traffic forwarded to your Nginx as HTTP
3. No certificate management needed

**Setup**:
```bash
# Configure tunnel (see Tunneling guide)
PANGOLIN_ENDPOINT=https://pangolin.bnkserve.org
NEWT_ID=<your-newt-id>
NEWT_SECRET=<your-newt-secret>

# Start Newt container
docker compose up -d newt
```

**Nginx Configuration**: Keep HTTP-only (tunnel handles HTTPS):
```nginx
server {
    listen 80;
    server_name api.cmlite.org;

    # No SSL config needed — tunnel terminates HTTPS
    location / {
        proxy_pass http://changemaker-v2-api:4000;
    }
}
```

**DNS Setup**: Point domain to tunnel endpoint (provided by Pangolin).

See [Tunneling](tunneling.md) for complete guide.

---

## Nginx SSL Configuration

### Strong TLS Settings

```nginx
server {
    listen 443 ssl http2;
    server_name api.cmlite.org;

    # Certificates
    ssl_certificate /etc/letsencrypt/live/cmlite.org/fullchain.pem;
    ssl_certificate_key /etc/letsencrypt/live/cmlite.org/privkey.pem;

    # Protocols (TLS 1.2+ only)
    ssl_protocols TLSv1.2 TLSv1.3;

    # Ciphers (secure + fast)
    ssl_ciphers 'ECDHE-ECDSA-AES128-GCM-SHA256:ECDHE-RSA-AES128-GCM-SHA256:ECDHE-ECDSA-AES256-GCM-SHA384:ECDHE-RSA-AES256-GCM-SHA384';
    ssl_prefer_server_ciphers on;

    # Session caching (performance)
    ssl_session_cache shared:SSL:10m;
    ssl_session_timeout 10m;

    # OCSP stapling (performance + privacy)
    ssl_stapling on;
    ssl_stapling_verify on;
    ssl_trusted_certificate /etc/letsencrypt/live/cmlite.org/chain.pem;

    # HSTS (already set globally in nginx.conf)
    # add_header Strict-Transport-Security "max-age=31536000; includeSubDomains" always;

    # ... locations
}
```

**Explanation**:
- **TLS 1.2+**: Disables insecure SSLv3, TLS 1.0/1.1
- **Ciphers**: ECDHE for forward secrecy, AES-GCM for speed
- **Session cache**: Reduces TLS handshake overhead
- **OCSP stapling**: Faster certificate validation

---

### HTTP/2

**Already enabled** (`:443 ssl http2`):
- Multiplexes requests over single connection
- Server push support (optional)
- Faster page loads

**No additional config needed** — Nginx handles HTTP/2 automatically.

---

### HSTS (HTTP Strict Transport Security)

**Already set globally** (in `nginx/nginx.conf`):
```nginx
add_header Strict-Transport-Security "max-age=31536000; includeSubDomains" always;
```

**Effect**:
- Browsers cache HTTPS requirement for 1 year
- Prevents downgrade attacks
- Applies to all subdomains

**Warning**: Only enable after verifying HTTPS works (can't easily undo).

**Test before enabling**:
```bash
# Test HTTPS works
curl -I https://api.cmlite.org

# Check for redirects
curl -L https://api.cmlite.org
```

---

## Certificate Renewal

### Automated Renewal (Certbot)

**Setup cron job**:
```bash
# Edit crontab
sudo crontab -e

# Add renewal job (checks twice daily)
0 0,12 * * * certbot renew --quiet --post-hook "docker compose -f /path/to/changemaker.lite/docker-compose.yml exec nginx nginx -s reload"
```

**Manual renewal**:
```bash
# Dry run (test)
sudo certbot renew --dry-run

# Real renewal
sudo certbot renew

# Reload Nginx
docker compose exec nginx nginx -s reload
```

**Renewal conditions**:
- Certificates expire in <30 days
- HTTP-01 challenge succeeds (port 80 must be open)

---

### Manual Renewal (Cloudflare)

**Cloudflare origin certificates** valid for 15 years — no renewal needed.

**If replacing certificate**:
1. Generate new cert in Cloudflare dashboard
2. Download files
3. Replace files in `/etc/ssl/cloudflare/`
4. Reload Nginx: `docker compose exec nginx nginx -s reload`

---

### Monitoring Expiry

**Check expiry date**:
```bash
# Via OpenSSL
echo | openssl s_client -connect api.cmlite.org:443 -servername api.cmlite.org 2>/dev/null | openssl x509 -noout -dates

# Output:
# notBefore=Jan  1 00:00:00 2024 GMT
# notAfter=Apr  1 23:59:59 2024 GMT
```

**Automated monitoring** (via Prometheus + Alertmanager):
```yaml
# In alerts.yml
- alert: SSLCertificateExpiringSoon
  expr: probe_ssl_earliest_cert_expiry - time() < 86400 * 30  # 30 days
  for: 1h
  labels:
    severity: warning
  annotations:
    summary: "SSL certificate expiring in <30 days"
```

---

## Testing SSL

### SSL Labs

**Online test**: https://www.ssllabs.com/ssltest/

**Target grade**: A or A+

**Common issues**:
- Missing intermediate certificate (use `fullchain.pem` not `cert.pem`)
- Weak ciphers (update `ssl_ciphers` list)
- Missing HSTS header (already set globally)

---

### Command Line

**Test TLS handshake**:
```bash
openssl s_client -connect api.cmlite.org:443 -servername api.cmlite.org
```

**Check certificate chain**:
```bash
openssl s_client -connect api.cmlite.org:443 -servername api.cmlite.org -showcerts
```

**Test specific protocol**:
```bash
# TLS 1.2
openssl s_client -connect api.cmlite.org:443 -tls1_2

# TLS 1.3
openssl s_client -connect api.cmlite.org:443 -tls1_3

# SSLv3 (should fail)
openssl s_client -connect api.cmlite.org:443 -ssl3
```

---

## Wildcard Certificates

**For `*.cmlite.org`** (covers all subdomains):

### Let's Encrypt (DNS-01 Challenge)

**Required**: API access to DNS provider (Cloudflare, Route53, etc.)

**Example** (Cloudflare):
```bash
# Install Cloudflare plugin
sudo apt install python3-certbot-dns-cloudflare

# Create credentials file
cat > ~/.secrets/cloudflare.ini <<EOF
dns_cloudflare_api_token = YOUR_API_TOKEN
EOF
chmod 600 ~/.secrets/cloudflare.ini

# Generate wildcard cert
sudo certbot certonly \
  --dns-cloudflare \
  --dns-cloudflare-credentials ~/.secrets/cloudflare.ini \
  -d cmlite.org \
  -d "*.cmlite.org" \
  --email admin@cmlite.org \
  --agree-tos
```

**Advantage**: Single certificate covers all subdomains (api, app, db, etc.).

---

## Troubleshooting

### Certificate Not Trusted

**Symptoms**: Browser shows "Not Secure" warning

**Causes**:
1. Missing intermediate certificate
2. Wrong certificate file
3. Certificate expired

**Solution**:
```bash
# Use fullchain.pem (includes intermediate)
ssl_certificate /etc/letsencrypt/live/cmlite.org/fullchain.pem;

# NOT cert.pem (missing intermediate)
# ssl_certificate /etc/letsencrypt/live/cmlite.org/cert.pem;  # ❌ WRONG

# Reload Nginx
docker compose exec nginx nginx -s reload
```

---

### Mixed Content Warnings

**Symptoms**: Some assets load via HTTP on HTTPS page

**Cause**: Hard-coded `http://` URLs in HTML/JS

**Solution**:
```javascript
// Change absolute URLs to protocol-relative
// ❌ WRONG
const apiUrl = 'http://api.cmlite.org';

// ✅ CORRECT
const apiUrl = 'https://api.cmlite.org';

// ✅ BEST (protocol-relative)
const apiUrl = location.protocol + '//api.cmlite.org';
```

---

### Renewal Failures

**Symptoms**: Certbot renewal fails

**Diagnosis**:
```bash
# Test renewal
sudo certbot renew --dry-run

# Check logs
sudo tail -f /var/log/letsencrypt/letsencrypt.log
```

**Common causes**:
- Port 80 blocked (HTTP-01 challenge fails)
- DNS not pointing to server (domain validation fails)
- Rate limit hit (5 certs/week per domain)

**Solution**:
```bash
# Check port 80 open
sudo netstat -tulpn | grep :80

# Test HTTP challenge
curl http://cmlite.org/.well-known/acme-challenge/test

# Use DNS-01 challenge instead (no port 80 needed)
sudo certbot certonly --dns-cloudflare ...
```

---

## Related Documentation

- **[Docker Compose](docker-compose.md)** — Nginx container setup
- **[Nginx Configuration](nginx.md)** — Reverse proxy config
- **[Tunneling](tunneling.md)** — Pangolin tunnel SSL
- **[Environment Variables](environment-variables.md)** — SSL-related env vars