fix: harden tenant auth and quality gates

api/src/auth/password-hasher.ts

@@ -0,0 +1,78 @@
+import { createHash, randomBytes, scrypt as scryptCallback, timingSafeEqual } from 'node:crypto';
+const VERSION = 1;
+const KEY_LENGTH = 32;
+const DEFAULT_N = 32768;
+const DEFAULT_R = 8;
+const DEFAULT_P = 1;
+const MAX_MEMORY = 64 * 1024 * 1024;
+const LEGACY_SHA256 = /^[a-f0-9]{64}$/i;
+
+export async function hashPassword(password: string) {
+  const salt = randomBytes(16);
+  const derived = await deriveScrypt(password, salt, KEY_LENGTH, {
+    N: DEFAULT_N,
+    r: DEFAULT_R,
+    p: DEFAULT_P,
+    maxmem: MAX_MEMORY,
+  });
+  return `$scrypt$v=${VERSION}$N=${DEFAULT_N},r=${DEFAULT_R},p=${DEFAULT_P}$${salt.toString('base64url')}$${derived.toString('base64url')}`;
+}
+
+export async function verifyPassword(password: string, encoded: string) {
+  if (isLegacySha256(encoded)) {
+    const candidate = Buffer.from(legacyHashPassword(password), 'hex');
+    const expected = Buffer.from(encoded, 'hex');
+    return candidate.length === expected.length && timingSafeEqual(candidate, expected);
+  }
+
+  const parsed = parseScryptHash(encoded);
+  if (!parsed) return false;
+  const derived = await deriveScrypt(password, parsed.salt, parsed.hash.length, {
+    N: parsed.N,
+    r: parsed.r,
+    p: parsed.p,
+    maxmem: MAX_MEMORY,
+  });
+  return derived.length === parsed.hash.length && timingSafeEqual(derived, parsed.hash);
+}
+
+export function passwordNeedsRehash(encoded: string) {
+  if (isLegacySha256(encoded)) return true;
+  const parsed = parseScryptHash(encoded);
+  return !parsed || parsed.version !== VERSION || parsed.N !== DEFAULT_N || parsed.r !== DEFAULT_R || parsed.p !== DEFAULT_P;
+}
+
+export function isLegacySha256(encoded: string) {
+  return LEGACY_SHA256.test(encoded);
+}
+
+export function legacyHashPassword(password: string) {
+  return createHash('sha256').update(password).digest('hex');
+}
+
+function parseScryptHash(encoded: string) {
+  const match = /^\$scrypt\$v=(\d+)\$N=(\d+),r=(\d+),p=(\d+)\$([A-Za-z0-9_-]+)\$([A-Za-z0-9_-]+)$/.exec(encoded);
+  if (!match) return undefined;
+  const [, version, N, r, p, salt, hash] = match;
+  const params = { version: Number(version), N: Number(N), r: Number(r), p: Number(p) };
+  if (!Number.isInteger(params.N) || params.N < 2 || params.N > DEFAULT_N
+    || !Number.isInteger(params.r) || params.r < 1 || params.r > DEFAULT_R
+    || !Number.isInteger(params.p) || params.p < 1 || params.p > DEFAULT_P) return undefined;
+  try {
+    const decodedSalt = Buffer.from(salt, 'base64url');
+    const decodedHash = Buffer.from(hash, 'base64url');
+    if (decodedSalt.length < 16 || decodedHash.length !== KEY_LENGTH) return undefined;
+    return { ...params, salt: decodedSalt, hash: decodedHash };
+  } catch {
+    return undefined;
+  }
+}
+
+function deriveScrypt(password: string, salt: Buffer, keyLength: number, options: { N: number; r: number; p: number; maxmem: number }) {
+  return new Promise<Buffer>((resolve, reject) => {
+    scryptCallback(password, salt, keyLength, options, (error, derivedKey) => {
+      if (error) reject(error);
+      else resolve(derivedKey);
+    });
+  });
+}