From 36b63a8c109a5a805e1835f67cf56d1a746f3bcc Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Stefan=20B=C3=BCrk?= <stefan@buerk.tech>
Date: Sun, 21 Apr 2024 17:47:29 +0200
Subject: [PATCH] [BUGFIX] Use Guzzle request to fetch external error page
content
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TYPO3 provides the ability to configure different error handlers for
specific (or all) error codes, as well as the error handler type
to use (core handler or custom).
The `\TYPO3\CMS\Core\Error\PageErrorHandler\PageContentErrorHandler`
allows to specify a target using the link handler. The default config
allows to define `LinkService::TYPE_PAGE` and `LinkService::TYPE_URL`.
After implementing and stabilizing the TYPO3 sub-request feature,
this particular error handler has been refactored to use an internal
sub-request to resolve the error page content: An external URL not
matching the same instance or having a page unavailable within
the TYPO3 instance will not return any content.
This change modifies the `PageContentErrorHandler` to send a Guzzle
request for an external URL instead of using internal sub-requests,
even if it would access the originating instance again. A limitation
is that the requested URL **must** return a HTTP status-code 200.
A custom request header is attached to this request. It is then
checked to avoid recurring errors or loops in the page-resolving
workflow.
Resolves: #103399
Related: #98396
Related: #94402
Releases: main, 12.4
Change-Id: If09158abd2aa9246bcb7a4fa41a0ad6e4a0f942c
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/83947
Reviewed-by: Thomas Hohn <tho@gyldendal.dk>
Reviewed-by: Stefan Bürk <stefan@buerk.tech>
Tested-by: Benni Mack <benni@typo3.org>
Tested-by: core-ci <typo3@b13.com>
Tested-by: Christian Kuhn <lolli@schwarzbu.ch>
Reviewed-by: Christian Kuhn <lolli@schwarzbu.ch>
Reviewed-by: Benni Mack <benni@typo3.org>
Tested-by: Stefan Bürk <stefan@buerk.tech>
---
.../PageContentErrorHandler.php | 57 +++++++++++++++++++
.../core/Tests/Unit/Site/Entity/SiteTest.php | 5 ++
2 files changed, 62 insertions(+)
diff --git a/typo3/sysext/core/Classes/Error/PageErrorHandler/PageContentErrorHandler.php b/typo3/sysext/core/Classes/Error/PageErrorHandler/PageContentErrorHandler.php
index fadf96c1e7f1..9a68a9a1a379 100644
--- a/typo3/sysext/core/Classes/Error/PageErrorHandler/PageContentErrorHandler.php
+++ b/typo3/sysext/core/Classes/Error/PageErrorHandler/PageContentErrorHandler.php
@@ -17,10 +17,13 @@ declare(strict_types=1);
namespace TYPO3\CMS\Core\Error\PageErrorHandler;
+use GuzzleHttp\Exception\GuzzleException;
+use Psr\Http\Message\RequestFactoryInterface;
use Psr\Http\Message\ResponseFactoryInterface;
use Psr\Http\Message\ResponseInterface;
use Psr\Http\Message\ServerRequestInterface;
use TYPO3\CMS\Core\Exception\SiteNotFoundException;
+use TYPO3\CMS\Core\Http\Client\GuzzleClientFactory;
use TYPO3\CMS\Core\Http\HtmlResponse;
use TYPO3\CMS\Core\Http\Uri;
use TYPO3\CMS\Core\LinkHandling\LinkService;
@@ -44,6 +47,8 @@ class PageContentErrorHandler implements PageErrorHandlerInterface
protected ResponseFactoryInterface $responseFactory;
protected SiteFinder $siteFinder;
protected LinkService $link;
+ protected RequestFactoryInterface $requestFactory;
+ protected GuzzleClientFactory $guzzleClientFactory;
/**
* PageContentErrorHandler constructor.
@@ -63,6 +68,8 @@ class PageContentErrorHandler implements PageErrorHandlerInterface
$this->responseFactory = $container->get(ResponseFactoryInterface::class);
$this->siteFinder = GeneralUtility::makeInstance(SiteFinder::class);
$this->link = $container->get(LinkService::class);
+ $this->requestFactory = $container->get(RequestFactoryInterface::class);
+ $this->guzzleClientFactory = $container->get(GuzzleClientFactory::class);
}
public function handlePageError(ServerRequestInterface $request, string $message, array $reasons = []): ResponseInterface
@@ -70,6 +77,7 @@ class PageContentErrorHandler implements PageErrorHandlerInterface
try {
$urlParams = $this->link->resolve($this->errorHandlerConfiguration['errorContentSource']);
$urlParams['pageuid'] = (int)($urlParams['pageuid'] ?? 0);
+ $urlType = $urlParams['type'] ?? LinkService::TYPE_UNKNOWN;
$resolvedUrl = $this->resolveUrl($request, $urlParams);
// avoid denial-of-service amplification scenario
@@ -79,6 +87,11 @@ class PageContentErrorHandler implements PageErrorHandlerInterface
$this->statusCode
);
}
+ // External URL most likely pointing to additional hosts or pages not contained in the current instance,
+ // and using internal sub requests would never receive a valid page. Send an external request instead.
+ if ($urlType === LinkService::TYPE_URL) {
+ return $this->sendExternalRequest($resolvedUrl, $request);
+ }
// Create a sub-request and do not take any special query parameters into account
$subRequest = $request->withQueryParams([])->withUri(new Uri($resolvedUrl))->withMethod('GET');
$subResponse = $this->stashEnvironment(fn(): ResponseInterface => $this->sendSubRequest($subRequest, $urlParams['pageuid'], $request));
@@ -128,6 +141,50 @@ class PageContentErrorHandler implements PageErrorHandlerInterface
return $this->application->handle($request);
}
+ /**
+ * Sends an external request to fetch the error page from a remote resource.
+ *
+ * A custom header is added and checked to mitigate request loops, which
+ * indicates additional configuration error in the error handler config.
+ */
+ protected function sendExternalRequest(string $url, ServerRequestInterface $originalRequest): ResponseInterface
+ {
+ if ($originalRequest->hasHeader('Requested-By')
+ && in_array('TYPO3 Error Handler', $originalRequest->getHeader('Requested-By'), true)
+ ) {
+ // If the header is set here, it is a recursive call within the same instance where an
+ // outer error handler called a page that results in another error handler call. To break
+ // the loop, we except here.
+ return new HtmlResponse(
+ 'The error page could not be resolved, the error page itself is not accessible',
+ $this->statusCode
+ );
+ }
+ try {
+ $request = $this->requestFactory->createRequest('GET', $url)
+ ->withHeader('Content-Type', 'text/html')
+ ->withHeader('Requested-By', 'TYPO3 Error Handler');
+ $response = $this->guzzleClientFactory->getClient()->send($request);
+ // In case global guzzle configuration has been changed to not throw an exception
+ // for error status codes, the response status code is checked here.
+ if ($response->getStatusCode() >= 300) {
+ return new HtmlResponse(
+ 'The error page could not be resolved, as the error page itself is not accessible',
+ $this->statusCode
+ );
+ }
+ return $this->responseFactory
+ ->createResponse($this->statusCode)
+ ->withHeader('Content-Type', $response->getHeader('Content-Type'))
+ ->withBody($response->getBody());
+ } catch (GuzzleException) {
+ return new HtmlResponse(
+ 'The error page could not be resolved, the error page itself is not accessible',
+ $this->statusCode
+ );
+ }
+ }
+
/**
* Resolve the URL (currently only page and external URL are supported)
*/
diff --git a/typo3/sysext/core/Tests/Unit/Site/Entity/SiteTest.php b/typo3/sysext/core/Tests/Unit/Site/Entity/SiteTest.php
index 7285c9be5b25..787a64c37f19 100644
--- a/typo3/sysext/core/Tests/Unit/Site/Entity/SiteTest.php
+++ b/typo3/sysext/core/Tests/Unit/Site/Entity/SiteTest.php
@@ -19,6 +19,7 @@ namespace TYPO3\CMS\Core\Tests\Unit\Site\Entity;
use PHPUnit\Framework\Attributes\DataProvider;
use PHPUnit\Framework\Attributes\Test;
+use Psr\Http\Message\RequestFactoryInterface;
use Psr\Http\Message\ResponseFactoryInterface;
use Symfony\Component\DependencyInjection\Container;
use TYPO3\CMS\Core\Cache\CacheManager;
@@ -190,7 +191,9 @@ final class SiteTest extends UnitTestCase
$container = new Container();
$container->set(Application::class, $app);
$container->set(Features::class, new Features());
+ $container->set(GuzzleClientFactory::class, new GuzzleClientFactory());
$container->set(RequestFactory::class, new RequestFactory(new GuzzleClientFactory()));
+ $container->set(RequestFactoryInterface::class, new RequestFactory(new GuzzleClientFactory()));
$container->set(ResponseFactoryInterface::class, new ResponseFactory());
$container->set(LinkService::class, $link);
$container->set(SiteFinder::class, $siteFinder);
@@ -267,7 +270,9 @@ final class SiteTest extends UnitTestCase
$container = new Container();
$container->set(Application::class, $app);
$container->set(Features::class, new Features());
+ $container->set(GuzzleClientFactory::class, new GuzzleClientFactory());
$container->set(RequestFactory::class, new RequestFactory(new GuzzleClientFactory()));
+ $container->set(RequestFactoryInterface::class, new RequestFactory(new GuzzleClientFactory()));
$container->set(ResponseFactoryInterface::class, new ResponseFactory());
$container->set(LinkService::class, $link);
$container->set(SiteFinder::class, $siteFinder);
--
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