[FEATURE] Use CSRF like tokens

The use of the token is intended to prevent CSRF attacks.

As a positive side effect, it also prevents (accidental) repeated sending. This occurs on iPhones,
for example, when the browser is reopened and the success page was still open in a tab)

See: https://docs.typo3.org/m/typo3/reference-coreapi/main/en-us/ApiOverview/Authentication/CSRFlikeRequestTokenHandling.html

Related: #286
Related: #1195

Classes/Controller/FormController.php

@@ -37,7 +37,10 @@
 use Throwable;
 use TYPO3\CMS\Core\Configuration\Exception\ExtensionConfigurationExtensionNotConfiguredException;
 use TYPO3\CMS\Core\Configuration\Exception\ExtensionConfigurationPathDoesNotExistException;
+use TYPO3\CMS\Core\Context\Context;
+use TYPO3\CMS\Core\Context\SecurityAspect;
 use TYPO3\CMS\Core\Http\PropagateResponseException;
+use TYPO3\CMS\Core\Security\RequestToken;
 use TYPO3\CMS\Core\Utility\ArrayUtility;
 use TYPO3\CMS\Core\Utility\GeneralUtility;
 use TYPO3\CMS\Extbase\Annotation as ExtbaseAnnotation;
@@ -82,12 +85,14 @@ public function formAction(): ResponseInterface
         );
         $form = $event->getForm();
         SessionUtility::saveFormStartInSession($this->settings, $form);
+        $requestToken = RequestToken::create('powermail/create');
         $this->view->assignMultiple(
             [
                 'form' => $form,
                 'ttContentData' => $this->contentObject->data,
                 'messageClass' => $this->messageClass,
                 'action' => ($this->settings['main']['confirmation'] ? 'checkConfirmation' : 'checkCreate'),
+                'requestToken' => $requestToken,
             ]
         );
 
@@ -262,6 +267,35 @@ public function createAction(Mail $mail, string $hash = ''): ResponseInterface
         if ($mail->getUid() !== null && !HashUtility::isHashValid($hash, $mail)) {
             return (new ForwardResponse('form'))->withoutArguments();
         }
+        $context = GeneralUtility::makeInstance(Context::class);
+        $securityAspect = SecurityAspect::provideIn($context);
+        $requestToken = $securityAspect->getReceivedRequestToken();
+
+        if ($requestToken === null) {
+            $this->addFlashMessage(
+                LocalizationUtility::translate('error_requesttoken_missing'),
+                \TYPO3\CMS\Core\Type\ContextualFeedbackSeverity::ERROR
+            );
+            $this->messageClass = 'error';
+            return (new ForwardResponse('form'))->withArguments(['messageClass' => $this->messageClass]);
+        }
+        if ($requestToken === false) {
+            $this->addFlashMessage(
+                LocalizationUtility::translate('error_requesttoken_not_verified'),
+                \TYPO3\CMS\Core\Type\ContextualFeedbackSeverity::ERROR
+            );
+            $this->messageClass = 'error';
+            return (new ForwardResponse('form'))->withArguments(['messageClass' => $this->messageClass]);
+        }
+        if ($requestToken->scope !== 'powermail/create') {
+            $this->addFlashMessage(
+                LocalizationUtility::translate('error_requesttoken_wrong_scope'),
+                \TYPO3\CMS\Core\Type\ContextualFeedbackSeverity::ERROR
+            );
+            $this->messageClass = 'error';
+            return (new ForwardResponse('form'))->withArguments(['messageClass' => $this->messageClass]);
+        }
+
         $event = GeneralUtility::makeInstance(FormControllerCreateActionBeforeRenderViewEvent::class, $mail, $hash, $this);
         $this->eventDispatcher->dispatch($event);
         $mail = $event->getMail();
@@ -322,6 +356,14 @@ public function createAction(Mail $mail, string $hash = ''): ResponseInterface
             $this->contentObject
         );
 
+        // The middleware takes care to remove the cookie in case no other
+        // nonce value shall be emitted during the current HTTP request
+        if ($requestToken->getSigningSecretIdentifier() !== null) {
+            $securityAspect->getSigningSecretResolver()->revokeIdentifier(
+                $requestToken->getSigningSecretIdentifier(),
+            );
+        }
+
         return $this->htmlResponse();
     }
 
@@ -372,6 +414,7 @@ protected function sendMailPreflight(Mail $mail, string $hash = ''): void
      */
     protected function prepareOutput(Mail $mail): void
     {
+        $requestToken = RequestToken::create('powermail/create');
         $this->view->assignMultiple(
             [
                 'variablesWithMarkers' => $this->mailRepository->getVariablesWithMarkersFromMail($mail, true),
@@ -382,6 +425,7 @@ protected function prepareOutput(Mail $mail): void
                 'uploadService' => $this->uploadService,
                 'powermail_rte' => $this->settings['thx']['body'],
                 'powermail_all' => TemplateUtility::powermailAll($mail, 'web', $this->settings, $this->actionMethodName),
+                'requestToken' => $requestToken,
             ]
         );
         $this->view->assignMultiple($this->mailRepository->getVariablesWithMarkersFromMail($mail, true));

Resources/Private/Language/locallang.xlf

@@ -154,6 +154,15 @@
 			<trans-unit id="error_mail_not_deleted" resname="error_mail_not_deleted">
 				<source>Mail could not be deleted. Wrong link or mail was probably already removed from the system.</source>
 			</trans-unit>
+			<trans-unit id="error_requesttoken_missing" resname="error_requesttoken_missing">
+				<source>No request token was provided in the request.</source>
+			</trans-unit>
+			<trans-unit id="error_requesttoken_not_verified" resname="error_requesttoken_not_verified">
+				<source>The given request token could not be verified with the nonce.</source>
+			</trans-unit>
+			<trans-unit id="error_requesttoken_wrong_scope" resname="error_requesttoken_wrong_scope">
+				<source>The given request token seems to be for a different scope.</source>
+			</trans-unit>
 			<trans-unit id="validationerror_mandatory" resname="validationerror_mandatory">
 				<source>This field must be filled!</source>
 			</trans-unit>

Resources/Private/Templates/Form/Confirmation.html

@@ -41,6 +41,7 @@ <h1><f:translate key="confirmation_message" /></h1>
 			</f:comment>
 			<f:form
 					action="checkCreate"
+					requestToken="{requestToken}"
 					section="c{ttContentData.uid}"
 					name="field"
 					enctype="multipart/form-data"

Resources/Private/Templates/Form/Form.html

@@ -17,6 +17,7 @@
             <div class="container-fluid">
                 <f:form
                     action="{action}"
+                    requestToken="{requestToken}"
                     section="c{ttContentData.uid}"
                     name="field"
                     enctype="multipart/form-data"