merge dc/DC-147 into p7-wave1

dashcaddy-api/routes/ca.js

@@ -392,7 +392,70 @@ ${safeDomain.includes('.') ? `DNS.2 = *.${safeDomain}` : ''}`;
       }))).filter(Boolean);
 
     ok(res, { certificates });
-  }, 'ca-certs'));
+    }, 'ca-certs'));
 
-  return router;
+    // DC-147: encrypted root-key backup. The root key never leaves the host
+    // unencrypted: this route returns an aes-256-cbc (pbkdf2, 100k iters)
+    // passphrase-wrapped copy plus a sha256 checksum, only after a passphrase
+    // is supplied, only to admin scope, rate-limited like the other cert
+    // endpoints (shares the /cert/* bucket — one fewer bypass to reason about).
+    router.post('/backup', ctx.asyncHandler(async (req, res) => {
+    if (!requireCaCertAdminScope(req, res)) return;
+
+    const clientIp = req.ip || req.connection?.remoteAddress || 'unknown';
+    const rl = caCertRateLimit(clientIp);
+    if (!rl.allowed) {
+    res.setHeader('Retry-After', Math.ceil(rl.retryAfterMs / 1000));
+    return ctx.errorResponse(res, 429,
+      `Rate limit exceeded for /api/v1/ca/backup (${CA_CERT_RATE_LIMIT.max} req/${CA_CERT_RATE_LIMIT.windowMs / 1000}s per IP). Retry in ${Math.ceil(rl.retryAfterMs / 1000)}s.`,
+      { code: 'DC147_RATE_LIMITED', retryAfterMs: rl.retryAfterMs });
+    }
+    res.setHeader('X-RateLimit-Limit', String(CA_CERT_RATE_LIMIT.max));
+    res.setHeader('X-RateLimit-Remaining', String(rl.remaining));
+
+    const { backupRootKey } = require('../src/network/ca-setup');
+    const passphrase = req.body && req.body.passphrase;
+    if (typeof passphrase !== 'string' || passphrase.length < 8) {
+    return ctx.errorResponse(res, 400,
+      'A passphrase of at least 8 characters (body: { "passphrase": "..." }) is required to wrap the backup.',
+      { code: 'DC147_PASSPHRASE_REQUIRED' });
+    }
+
+    // Root key lives in the CA cert dir (ca-setup.js flow) or the Caddy PKI
+    // dir (existing pipeline). Probe both; refuse politely when absent.
+    const path = require('path');
+    const candidates = [
+    path.join(platformPaths.caCertDir, 'root.key'),
+    path.join(platformPaths.pkiDir, 'root.key')
+    ];
+    const keyPath = candidates.find((p) => fs.existsSync(p));
+    if (!keyPath) {
+    return ctx.errorResponse(res, 404, 'Root key not found on this host.', { code: 'DC147_ROOT_KEY_MISSING' });
+    }
+
+    let backup;
+    try {
+    backup = backupRootKey({ dir: path.dirname(keyPath), passphrase });
+    } catch (e) {
+    return ctx.errorResponse(res, 500, `Backup generation failed: ${e.message}`, { code: 'DC147_BACKUP_FAILED' });
+    }
+
+    // Defense-in-depth: never ship the raw key, even if a future refactor
+    // breaks the cipher below us.
+    if (typeof backup.ciphertext !== 'string' || backup.ciphertext.includes('PRIVATE KEY')) {
+    return ctx.errorResponse(res, 500, 'Backup sanity check failed — refusing to emit.', { code: 'DC147_BACKUP_UNSAFE' });
+    }
+
+    ok(res, {
+    backup: {
+      ciphertext: backup.ciphertext,
+      sha256: backup.sha256,
+      algorithm: backup.algorithm,
+      filename: 'dashcaddy-root-key.backup.enc'
+    },
+    instructions: 'Decrypt with: openssl aes-256-cbc -d -pbkdf2 -iter 100000 -a -in dashcaddy-root-key.backup.enc -out root.key'
+    });
+    }, 'ca-backup'));
+
+    return router;
 };