Download the PHP package straschek-io/typo3-tor-blocker without Composer

TYPO3 Tor Blocker

This extension answers every frontend request coming from a Tor exit node with 403 Forbidden and a short notice page.

Form spam bots like to hide behind the Tor network: every submission arrives from a different exit node, so blocking single IP addresses is pointless. The Tor Project publishes the complete list of exit nodes, which makes blocking all of them straightforward. Legitimate visitors via Tor are rare on most websites; if they matter for yours, this extension is not for you.

How to install

Composer mode:

Classic mode: copy the extension to typo3conf/ext/tor_blocker/, activate it in the extension manager and dump the autoload information.

How to use

1. Download the list once, as the user the web server runs as (see Permissions):

2. Keep it up to date, hourly. Either add a scheduler task "Execute console commands" with torblocker:update, or skip the scheduler and use a cron job running as the web server user:

   In classic mode the binary is typo3/sysext/core/bin/typo3.

3. Keep an eye on it: the reports module (system extension reports) shows the number of stored addresses and the age of the list under "Tor Blocker". It warns when no list is stored or the list is older than 24 hours, and reports an error when the stored list cannot be loaded.

4. Check that it works: request the site from a listed address (Tor Browser, or curl from a listed exit node) and expect a 403 with Cache-Control: no-store.

That's it. The middleware runs first in the frontend stack, before static file caches and before the page is resolved. The backend is never blocked.

Configuration

Extension configuration, all optional:

The notice page is available in English and German, chosen by the browser's Accept-Language header (best quality first), since the site and its languages are not resolved yet at that point.

Good to know

• The list is stored as a PHP array in <var path>/tor_blocker/exit-nodes.php (typo3temp/var/ in classic mode, var/ in composer mode). Opcache keeps it in memory, so a lookup costs a single isset().
• The file is replaced atomically. A failed or implausible download never touches the stored list, and the command exits with 1.
• Fail-open: without a stored list nobody is blocked. Deleting the file is the emergency switch; the next scheduler run brings it back. A list that exists but cannot be loaded blocks nobody either and is logged as an error (TYPO3.CMS.Log component StraschekIo.TorBlocker.Repository.ExitNodeRepository).
• Addresses are normalized on both sides before they are compared: IPv6 is compressed and lower cased, IPv4-mapped IPv6 addresses (::ffff:192.0.2.1, as reported by dual stack sockets with ipv6only=off) count as the IPv4 address.
• The client address is determined like the core does it (NormalizedParams), so $GLOBALS['TYPO3_CONF_VARS']['SYS']['reverseProxyIP'] is respected. Behind a proxy or CDN, configure it, or the proxy's address is checked instead of the visitor's. Never set it to * without a proxy: clients could then fake their address via X-Forwarded-For.
• Static files are delivered by the web server and are not affected.

Permissions

torblocker:update runs on the command line, the list is read by the web server process. The directory and the file get the permissions configured in $GLOBALS['TYPO3_CONF_VARS']['SYS'] (folderCreateMask, fileCreateMask, createGroup; defaults 2775, 0664, none), independent of the umask of the CLI user. Run the command and the scheduler as the web server user anyway, or make sure that user can read <var path>/tor_blocker/exit-nodes.php; the command fails with exit code 1 if the file is not readable after writing.

Opcache

The web server's opcache notices the new list by its modification time, within opcache.revalidate_freq seconds (default 2). With opcache.validate_timestamps = 0 the web server keeps the old list, and also keeps blocking after the file was deleted, until PHP-FPM is reloaded. Add the reload to your update routine in that case.

Development

Bootstraps a full TYPO3 14.3 dev instance (DDEV required, PHP 8.4) with a seeded page and a dev list that blocks the loopback addresses only, so requests from inside the web container get the notice page while your browser gets the page. Frontend: https://typo3-tor-blocker.ddev.site/ — Backend: /typo3 (admin / TorBlocker14!) Run tests with ddev composer test, code style with ddev composer cs.

The lowest supported combination, TYPO3 10.4 on PHP 7.4, runs in Docker:

Activate the pre-commit hook once per clone: git config core.hooksPath .githooks

Compatibility

Compatible with TYPO3 10.4, 12.4, 13.4 and 14.3, PHP 7.4 – 8.5. TYPO3 11.5 is not tested. Covered by PHPUnit tests against TYPO3 10.4 (PHP 7.4), 12.4 (PHP 8.2), 13.4 (PHP 8.3) and 14.3 (PHP 8.3 – 8.5). From TYPO3 13 on the notice page is rendered through the ViewFactoryInterface, on 10 and 12 through StandaloneView.

Works for me, may work for you.