Visitor sign in kiosk: multi-site, badge printing, WWCC expiry warnings, admin accounts with 2FA

src/auth.js

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+import crypto from 'node:crypto';
+
+/* ------------------------------------------------------------ passwords */
+// scrypt is built into Node, so there is no native module to compile in the image.
+
+export function hashPassword(password) {
+  const salt = crypto.randomBytes(16);
+  const hash = crypto.scryptSync(String(password), salt, 64, { N: 16384, r: 8, p: 1 });
+  return `scrypt$${salt.toString('base64')}$${hash.toString('base64')}`;
+}
+
+export function verifyPassword(password, stored) {
+  try {
+    const [scheme, saltB64, hashB64] = String(stored).split('$');
+    if (scheme !== 'scrypt') return false;
+    const expected = Buffer.from(hashB64, 'base64');
+    const actual = crypto.scryptSync(String(password), Buffer.from(saltB64, 'base64'), expected.length, {
+      N: 16384,
+      r: 8,
+      p: 1,
+    });
+    return crypto.timingSafeEqual(expected, actual);
+  } catch {
+    return false;
+  }
+}
+
+export function passwordProblem(password) {
+  const value = String(password || '');
+  if (value.length < 12) return 'Use at least 12 characters.';
+  if (!/[a-z]/.test(value) || !/[A-Z]/.test(value)) return 'Mix upper and lower case.';
+  if (!/\d/.test(value)) return 'Include at least one number.';
+  return null;
+}
+
+export function randomPassword() {
+  // Readable enough to hand over verbally, still 60+ bits of entropy.
+  const words = crypto.randomBytes(9).toString('base64url').replace(/[-_]/g, '');
+  return `Vs${words}9`;
+}
+
+/* ----------------------------------------------------------- base32 */
+
+const ALPHABET = 'ABCDEFGHIJKLMNOPQRSTUVWXYZ234567';
+
+export function base32Encode(buffer) {
+  let bits = 0;
+  let value = 0;
+  let output = '';
+  for (const byte of buffer) {
+    value = (value << 8) | byte;
+    bits += 8;
+    while (bits >= 5) {
+      output += ALPHABET[(value >>> (bits - 5)) & 31];
+      bits -= 5;
+    }
+  }
+  if (bits > 0) output += ALPHABET[(value << (5 - bits)) & 31];
+  return output;
+}
+
+export function base32Decode(input) {
+  const clean = String(input).toUpperCase().replace(/[^A-Z2-7]/g, '');
+  let bits = 0;
+  let value = 0;
+  const bytes = [];
+  for (const char of clean) {
+    value = (value << 5) | ALPHABET.indexOf(char);
+    bits += 5;
+    if (bits >= 8) {
+      bytes.push((value >>> (bits - 8)) & 255);
+      bits -= 8;
+    }
+  }
+  return Buffer.from(bytes);
+}
+
+/* -------------------------------------------------------------- TOTP */
+
+export function generateTotpSecret() {
+  return base32Encode(crypto.randomBytes(20));
+}
+
+function hotp(secretBuffer, counter) {
+  const buf = Buffer.alloc(8);
+  buf.writeBigUInt64BE(BigInt(counter));
+  const digest = crypto.createHmac('sha1', secretBuffer).update(buf).digest();
+  const offset = digest[digest.length - 1] & 0x0f;
+  const code =
+    ((digest[offset] & 0x7f) << 24) |
+    ((digest[offset + 1] & 0xff) << 16) |
+    ((digest[offset + 2] & 0xff) << 8) |
+    (digest[offset + 3] & 0xff);
+  return String(code % 1_000_000).padStart(6, '0');
+}
+
+export function totpCode(secret, atMs = Date.now(), stepSeconds = 30) {
+  return hotp(base32Decode(secret), Math.floor(atMs / 1000 / stepSeconds));
+}
+
+/** Allows one step either side, which covers a phone clock that has drifted a little. */
+export function verifyTotp(secret, token, window = 1) {
+  const candidate = String(token || '').replace(/\D/g, '');
+  if (candidate.length !== 6) return false;
+  const counter = Math.floor(Date.now() / 1000 / 30);
+  const buffer = base32Decode(secret);
+  for (let drift = -window; drift <= window; drift += 1) {
+    const expected = hotp(buffer, counter + drift);
+    if (crypto.timingSafeEqual(Buffer.from(expected), Buffer.from(candidate))) return true;
+  }
+  return false;
+}
+
+export function otpauthUrl({ secret, email, issuer }) {
+  const label = encodeURIComponent(`${issuer}:${email}`);
+  const params = new URLSearchParams({ secret, issuer, algorithm: 'SHA1', digits: '6', period: '30' });
+  return `otpauth://totp/${label}?${params}`;
+}
+
+/* --------------------------------------------------- recovery codes */
+
+export function generateRecoveryCodes(count = 8) {
+  return Array.from({ length: count }, () =>
+    crypto.randomBytes(5).toString('hex').replace(/(.{5})(.{5})/, '$1-$2')
+  );
+}
+
+const digest = (code) =>
+  crypto.createHash('sha256').update(String(code).toLowerCase().replace(/[^a-z0-9]/g, '')).digest('hex');
+
+export function hashRecoveryCodes(codes) {
+  return JSON.stringify(codes.map(digest));
+}
+
+/** Returns the remaining codes if one matched, or null. Used codes are burnt. */
+export function consumeRecoveryCode(storedJson, candidate) {
+  try {
+    const hashes = JSON.parse(storedJson || '[]');
+    const target = digest(candidate);
+    const index = hashes.indexOf(target);
+    if (index === -1) return null;
+    hashes.splice(index, 1);
+    return JSON.stringify(hashes);
+  } catch {
+    return null;
+  }
+}