AFFiNE-Mirror/packages/frontend/apps/electron/src/main/security-restrictions.ts

import { app } from 'electron';

import { anotherHost, mainHost } from './constants';
import { openExternalSafely } from './security/open-external';
import { validateRedirectProxyUrl } from './security/redirect-proxy';

app.on('web-contents-created', (_, contents) => {
  const isInternalUrl = (url: string) => {
    try {
      const parsed = new URL(url);
      if (
        parsed.protocol === 'assets:' &&
        (parsed.hostname === mainHost || parsed.hostname === anotherHost)
      ) {
        return true;
      }
    } catch {}
    return false;
  };
  /**
   * Block navigation to origins not on the allowlist.
   *
   * Navigation is a common attack vector. If an attacker can convince the app to navigate away
   * from its current page, they can possibly force the app to open web sites on the Internet.
   *
   * @see https://www.electronjs.org/docs/latest/tutorial/security#13-disable-or-limit-navigation
   */
  contents.on('will-navigate', (event, url) => {
    if (isInternalUrl(url)) {
      return;
    }
    // Prevent navigation
    event.preventDefault();
    openExternalSafely(url).catch(error => {
      console.error('[security] Failed to open external URL:', error);
    });
  });

  /**
   * Hyperlinks to allowed sites open in the default browser.
   *
   * The creation of new `webContents` is a common attack vector. Attackers attempt to convince the app to create new windows,
   * frames, or other renderer processes with more privileges than they had before; or with pages opened that they couldn't open before.
   * You should deny any unexpected window creation.
   *
   * @see https://www.electronjs.org/docs/latest/tutorial/security#14-disable-or-limit-creation-of-new-windows
   * @see https://www.electronjs.org/docs/latest/tutorial/security#15-do-not-use-openexternal-with-untrusted-content
   */
  contents.setWindowOpenHandler(({ url }) => {
    if (!isInternalUrl(url)) {
      openExternalSafely(url).catch(error => {
        console.error('[security] Failed to open external URL:', error);
      });
    } else if (url.includes('/redirect-proxy')) {
      const result = validateRedirectProxyUrl(url);
      if (!result.allow) {
        console.warn(
          `[security] Blocked redirect proxy: ${result.reason}`,
          result.redirectTarget ?? url
        );
        return { action: 'deny' };
      }

      openExternalSafely(result.redirectTarget).catch(error => {
        console.error('[security] Failed to open external URL:', error);
      });
    }
    // Prevent creating new window in application
    return { action: 'deny' };
  });
});