smartradius/test/server/test.chap.ts

import { expect, tap } from '@git.zone/tstest/tapbundle';
import * as crypto from 'crypto';
import { RadiusAuthenticator } from '../../ts_server/index.js';

tap.test('should calculate CHAP response per RFC', async () => {
  // CHAP-Response = MD5(CHAP-ID + Password + Challenge)
  const chapId = 42;
  const password = 'mypassword';
  const challenge = crypto.randomBytes(16);

  const response = RadiusAuthenticator.calculateChapResponse(chapId, password, challenge);

  // Verify manually
  const md5 = crypto.createHash('md5');
  md5.update(Buffer.from([chapId]));
  md5.update(Buffer.from(password, 'utf8'));
  md5.update(challenge);
  const expected = md5.digest();

  expect(response.length).toEqual(16);
  expect(response.equals(expected)).toBeTruthy();
});

tap.test('should verify valid CHAP response', async () => {
  const chapId = 1;
  const password = 'correctpassword';
  const challenge = crypto.randomBytes(16);

  // Calculate the expected response
  const response = RadiusAuthenticator.calculateChapResponse(chapId, password, challenge);

  // Build CHAP-Password attribute: CHAP Ident (1 byte) + Response (16 bytes)
  const chapPassword = Buffer.allocUnsafe(17);
  chapPassword.writeUInt8(chapId, 0);
  response.copy(chapPassword, 1);

  // Should verify with correct password
  const isValid = RadiusAuthenticator.verifyChapResponse(chapPassword, challenge, password);
  expect(isValid).toBeTruthy();
});

tap.test('should reject CHAP response with wrong password', async () => {
  const chapId = 1;
  const correctPassword = 'correctpassword';
  const wrongPassword = 'wrongpassword';
  const challenge = crypto.randomBytes(16);

  // Calculate response with correct password
  const response = RadiusAuthenticator.calculateChapResponse(chapId, correctPassword, challenge);

  // Build CHAP-Password attribute
  const chapPassword = Buffer.allocUnsafe(17);
  chapPassword.writeUInt8(chapId, 0);
  response.copy(chapPassword, 1);

  // Should NOT verify with wrong password
  const isValid = RadiusAuthenticator.verifyChapResponse(chapPassword, challenge, wrongPassword);
  expect(isValid).toBeFalsy();
});

tap.test('should reject CHAP response with wrong challenge', async () => {
  const chapId = 1;
  const password = 'mypassword';
  const correctChallenge = crypto.randomBytes(16);
  const wrongChallenge = crypto.randomBytes(16);

  // Calculate response with correct challenge
  const response = RadiusAuthenticator.calculateChapResponse(chapId, password, correctChallenge);

  // Build CHAP-Password attribute
  const chapPassword = Buffer.allocUnsafe(17);
  chapPassword.writeUInt8(chapId, 0);
  response.copy(chapPassword, 1);

  // Should NOT verify with wrong challenge
  const isValid = RadiusAuthenticator.verifyChapResponse(chapPassword, wrongChallenge, password);
  expect(isValid).toBeFalsy();
});

tap.test('should reject CHAP response with wrong identifier', async () => {
  const correctChapId = 1;
  const wrongChapId = 2;
  const password = 'mypassword';
  const challenge = crypto.randomBytes(16);

  // Calculate response with correct CHAP ID
  const response = RadiusAuthenticator.calculateChapResponse(correctChapId, password, challenge);

  // Build CHAP-Password with WRONG CHAP ID
  const chapPassword = Buffer.allocUnsafe(17);
  chapPassword.writeUInt8(wrongChapId, 0);  // Wrong ID
  response.copy(chapPassword, 1);

  // Should NOT verify
  const isValid = RadiusAuthenticator.verifyChapResponse(chapPassword, challenge, password);
  expect(isValid).toBeFalsy();
});

tap.test('should reject invalid CHAP-Password length', async () => {
  const challenge = crypto.randomBytes(16);
  const password = 'mypassword';

  // CHAP-Password must be exactly 17 bytes (1 + 16)
  const invalidChapPassword = Buffer.alloc(16);  // Too short

  const isValid = RadiusAuthenticator.verifyChapResponse(invalidChapPassword, challenge, password);
  expect(isValid).toBeFalsy();

  const tooLongChapPassword = Buffer.alloc(18);  // Too long
  const isValid2 = RadiusAuthenticator.verifyChapResponse(tooLongChapPassword, challenge, password);
  expect(isValid2).toBeFalsy();
});

tap.test('should handle all CHAP ID values (0-255)', async () => {
  const password = 'testpassword';
  const challenge = crypto.randomBytes(16);

  for (const chapId of [0, 1, 127, 128, 254, 255]) {
    const response = RadiusAuthenticator.calculateChapResponse(chapId, password, challenge);

    const chapPassword = Buffer.allocUnsafe(17);
    chapPassword.writeUInt8(chapId, 0);
    response.copy(chapPassword, 1);

    const isValid = RadiusAuthenticator.verifyChapResponse(chapPassword, challenge, password);
    expect(isValid).toBeTruthy();
  }
});

tap.test('should handle special characters in password', async () => {
  const chapId = 1;
  const password = '!@#$%^&*()_+-=[]{}|;:,.<>?~`';
  const challenge = crypto.randomBytes(16);

  const response = RadiusAuthenticator.calculateChapResponse(chapId, password, challenge);

  const chapPassword = Buffer.allocUnsafe(17);
  chapPassword.writeUInt8(chapId, 0);
  response.copy(chapPassword, 1);

  const isValid = RadiusAuthenticator.verifyChapResponse(chapPassword, challenge, password);
  expect(isValid).toBeTruthy();
});

tap.test('should handle unicode password', async () => {
  const chapId = 1;
  const password = '密码パスワード';  // Chinese + Japanese
  const challenge = crypto.randomBytes(16);

  const response = RadiusAuthenticator.calculateChapResponse(chapId, password, challenge);

  const chapPassword = Buffer.allocUnsafe(17);
  chapPassword.writeUInt8(chapId, 0);
  response.copy(chapPassword, 1);

  const isValid = RadiusAuthenticator.verifyChapResponse(chapPassword, challenge, password);
  expect(isValid).toBeTruthy();
});

tap.test('should handle empty password', async () => {
  const chapId = 1;
  const password = '';
  const challenge = crypto.randomBytes(16);

  const response = RadiusAuthenticator.calculateChapResponse(chapId, password, challenge);

  const chapPassword = Buffer.allocUnsafe(17);
  chapPassword.writeUInt8(chapId, 0);
  response.copy(chapPassword, 1);

  const isValid = RadiusAuthenticator.verifyChapResponse(chapPassword, challenge, password);
  expect(isValid).toBeTruthy();
});

tap.test('should handle very long password', async () => {
  const chapId = 1;
  const password = 'a'.repeat(1000);  // Very long password
  const challenge = crypto.randomBytes(16);

  const response = RadiusAuthenticator.calculateChapResponse(chapId, password, challenge);

  const chapPassword = Buffer.allocUnsafe(17);
  chapPassword.writeUInt8(chapId, 0);
  response.copy(chapPassword, 1);

  const isValid = RadiusAuthenticator.verifyChapResponse(chapPassword, challenge, password);
  expect(isValid).toBeTruthy();
});

tap.test('should handle different challenge lengths', async () => {
  const chapId = 1;
  const password = 'testpassword';

  // CHAP challenge can be various lengths
  for (const length of [8, 16, 24, 32]) {
    const challenge = crypto.randomBytes(length);

    const response = RadiusAuthenticator.calculateChapResponse(chapId, password, challenge);

    const chapPassword = Buffer.allocUnsafe(17);
    chapPassword.writeUInt8(chapId, 0);
    response.copy(chapPassword, 1);

    const isValid = RadiusAuthenticator.verifyChapResponse(chapPassword, challenge, password);
    expect(isValid).toBeTruthy();
  }
});

export default tap.start();