feat(auth): admin TOTP MFA — enrollment, login challenge, recovery, CLI reset

Backend for #738. Real TOTP 2FA for admin accounts, all roles incl. super_admin (closes #735). - mfaService: otplib TOTP; AES-256-GCM encryption of the secret at rest (key derived from MFA_ENCRYPTION_KEY or JWT_SECRET); bcrypt-hashed, single-use recovery codes; otpauth URI + QR. - Migration 151: adds two_factor_recovery_codes + two_factor_enrolled_at (secret/enabled columns already existed from legacy 016). - Enrollment endpoints (behind adminAuth, per-user): GET /mfa/status, POST /mfa/{setup,enable,disable,recovery-codes}. Disable/regenerate require a current code so a hijacked session can't strip 2FA. - Login challenge: /admin/login returns {mfaRequired, mfaToken} (no session) when 2FA is on; /admin/login/mfa exchanges a TOTP or recovery code for the session. Lockout counter is NOT reset until the second factor passes, so MFA brute-force is rate-limited too. - CLI break-glass: scripts/reset-admin-mfa.js --email <e> | --all --yes, audit-logged, matches reset-admin-password.js convention. - Docs + optional MFA_ENCRYPTION_KEY env. Verified end-to-end on a live backend: enroll (super_admin), challenge, TOTP + single-use recovery login, disable, and CLI reset.
2026-07-03 11:33:38 +02:00
parent 5b26dbd935
commit 72e2ef6721
8 changed files with 771 additions and 41 deletions
@@ -0,0 +1,183 @@
+/**
+ * mfaService — TOTP (RFC 6238) multi-factor auth for admin accounts (#738).
+ *
+ * Responsibilities:
+ *   - generate/verify TOTP secrets (otplib, standard SHA1/6-digit/30s so
+ *     Google Authenticator / Authy / 1Password all work);
+ *   - encrypt the secret at rest (AES-256-GCM) so a DB leak alone doesn't
+ *     yield working authenticator seeds;
+ *   - generate/verify one-time recovery codes, hashed (bcrypt) and single-use;
+ *   - build the otpauth:// URI + QR data-URL for enrollment.
+ *
+ * The encryption key is derived (scrypt) from MFA_ENCRYPTION_KEY when set,
+ * otherwise from JWT_SECRET. Rotating either invalidates stored secrets —
+ * the same blast radius as rotating JWT_SECRET already has for sessions, and
+ * `reset-admin-mfa.js` is the recovery path.
+ */
+
+const crypto = require('crypto');
+const bcrypt = require('bcrypt');
+const { authenticator } = require('otplib');
+const QRCode = require('qrcode');
+
+// Standard TOTP params; window:1 tolerates ±1 step (30s) of clock drift.
+authenticator.options = { window: 1 };
+
+const ISSUER = 'PicPeak';
+const RECOVERY_CODE_COUNT = 10;
+const RECOVERY_CODE_BYTES = 10; // ~80 bits of entropy per code
+const RECOVERY_BCRYPT_ROUNDS = 10;
+
+const ENC_ALGO = 'aes-256-gcm';
+const ENC_SALT = 'picpeak-mfa-secret-v1'; // fixed: derivation must be stable
+
+function getEncryptionKey() {
+  const material = process.env.MFA_ENCRYPTION_KEY || process.env.JWT_SECRET;
+  if (!material) {
+    throw new Error('mfaService: MFA_ENCRYPTION_KEY or JWT_SECRET must be set');
+  }
+  return crypto.scryptSync(material, ENC_SALT, 32);
+}
+
+/** Generate a fresh base32 TOTP secret. */
+function generateSecret() {
+  return authenticator.generateSecret();
+}
+
+/** AES-256-GCM encrypt a secret → "iv.tag.ciphertext" (all base64url). */
+function encryptSecret(plainSecret) {
+  const key = getEncryptionKey();
+  const iv = crypto.randomBytes(12);
+  const cipher = crypto.createCipheriv(ENC_ALGO, key, iv);
+  const ct = Buffer.concat([cipher.update(plainSecret, 'utf8'), cipher.final()]);
+  const tag = cipher.getAuthTag();
+  return [iv, tag, ct].map((b) => b.toString('base64url')).join('.');
+}
+
+/** Reverse of encryptSecret. Throws on tamper/wrong key. */
+function decryptSecret(stored) {
+  const key = getEncryptionKey();
+  const [ivB64, tagB64, ctB64] = String(stored).split('.');
+  if (!ivB64 || !tagB64 || !ctB64) {
+    throw new Error('mfaService: malformed encrypted secret');
+  }
+  const decipher = crypto.createDecipheriv(ENC_ALGO, key, Buffer.from(ivB64, 'base64url'));
+  decipher.setAuthTag(Buffer.from(tagB64, 'base64url'));
+  const pt = Buffer.concat([decipher.update(Buffer.from(ctB64, 'base64url')), decipher.final()]);
+  return pt.toString('utf8');
+}
+
+/** Verify a 6-digit TOTP code against the (plaintext) secret. */
+function verifyTotp(code, plainSecret) {
+  if (!code || !plainSecret) return false;
+  try {
+    return authenticator.verify({ token: String(code).replace(/\s+/g, ''), secret: plainSecret });
+  } catch {
+    return false;
+  }
+}
+
+/** Verify a code against a STORED (encrypted) secret. */
+function verifyTotpEncrypted(code, storedSecret) {
+  try {
+    return verifyTotp(code, decryptSecret(storedSecret));
+  } catch {
+    return false;
+  }
+}
+
+/** otpauth:// URI for an authenticator app. */
+function buildOtpauthUri(accountName, plainSecret) {
+  return authenticator.keyuri(accountName, ISSUER, plainSecret);
+}
+
+/** QR code (PNG data URL) for the otpauth URI. */
+async function buildQrDataUrl(otpauthUri) {
+  return QRCode.toDataURL(otpauthUri, { errorCorrectionLevel: 'M', margin: 1, width: 240 });
+}
+
+/** Format a raw code as human-friendly groups, e.g. "abcd-efgh-jk". */
+function formatRecoveryCode(raw) {
+  return raw.match(/.{1,4}/g).join('-');
+}
+
+/**
+ * Generate RECOVERY_CODE_COUNT one-time codes. Returns the plaintext codes
+ * (shown to the admin ONCE) and their bcrypt hashes (persisted).
+ */
+async function generateRecoveryCodes() {
+  const plain = [];
+  const hashed = [];
+  for (let i = 0; i < RECOVERY_CODE_COUNT; i++) {
+    // base32-ish, lowercase, no ambiguous chars
+    const raw = crypto.randomBytes(RECOVERY_CODE_BYTES)
+      .toString('base64')
+      .replace(/[^a-zA-Z0-9]/g, '')
+      .toLowerCase()
+      .slice(0, 10);
+    const code = formatRecoveryCode(raw);
+    plain.push(code);
+    hashed.push(await bcrypt.hash(code, RECOVERY_BCRYPT_ROUNDS));
+  }
+  return { plain, hashed };
+}
+
+function normalizeRecoveryInput(code) {
+  return String(code || '').trim().toLowerCase();
+}
+
+/**
+ * Check a submitted recovery code against the stored hash array. On match,
+ * returns the remaining hashes (matched one removed — single use). On miss,
+ * matched:false and the array unchanged.
+ *
+ * @param {string[]} storedHashes
+ * @returns {Promise<{matched: boolean, remainingHashes: string[]}>}
+ */
+async function consumeRecoveryCode(code, storedHashes) {
+  const input = normalizeRecoveryInput(code);
+  const hashes = Array.isArray(storedHashes) ? storedHashes : [];
+  if (!input) return { matched: false, remainingHashes: hashes };
+  for (let i = 0; i < hashes.length; i++) {
+    // eslint-disable-next-line no-await-in-loop
+    if (await bcrypt.compare(input, hashes[i])) {
+      const remaining = hashes.slice(0, i).concat(hashes.slice(i + 1));
+      return { matched: true, remainingHashes: remaining };
+    }
+  }
+  return { matched: false, remainingHashes: hashes };
+}
+
+/** True when an admin row has MFA enabled (coerces SQLite/PG boolean shapes). */
+function isEnrolled(admin) {
+  const v = admin && admin.two_factor_enabled;
+  return v === true || v === 1 || v === '1';
+}
+
+/** Parse the DB column (JSON text) into an array of hashes. */
+function parseRecoveryCodes(raw) {
+  if (!raw) return [];
+  try {
+    const arr = typeof raw === 'string' ? JSON.parse(raw) : raw;
+    return Array.isArray(arr) ? arr : [];
+  } catch {
+    return [];
+  }
+}
+
+module.exports = {
+  generateSecret,
+  encryptSecret,
+  decryptSecret,
+  verifyTotp,
+  verifyTotpEncrypted,
+  buildOtpauthUri,
+  buildQrDataUrl,
+  generateRecoveryCodes,
+  consumeRecoveryCode,
+  parseRecoveryCodes,
+  isEnrolled,
+  formatRecoveryCode,
+  ISSUER,
+  RECOVERY_CODE_COUNT,
+};