fix(core): Throttle lost-password reset form when link is disabled

When password reset links were disabled, the reset form did not rate-limit
failed token attempts, leaving that endpoint open to unthrottled token
guessing. Failed attempts on the form are now always throttled, consistent
with the other reset steps.

Signed-off-by: nfebe <fenn25.fn@gmail.com>

core/Controller/LostController.php

@@ -90,24 +90,19 @@ class LostController extends Controller {
 		try {
 			$this->checkPasswordResetToken($token, $userId);
 		} catch (Exception $e) {
-			if ($this->config->getSystemValue('lost_password_link', '') !== 'disabled'
-				|| ($e instanceof InvalidTokenException
-					&& !in_array($e->getCode(), [InvalidTokenException::TOKEN_NOT_FOUND, InvalidTokenException::USER_UNKNOWN]))
-			) {
-				$response = new TemplateResponse(
-					'core', 'error', [
-						'errors' => [['error' => $e->getMessage()]]
-					],
-					TemplateResponse::RENDER_AS_GUEST
-				);
-				$response->throttle();
-				return $response;
+			if ($this->config->getSystemValue('lost_password_link', '') === 'disabled') {
+				$message = $this->l10n->t('Password reset is disabled');
+			} else {
+				$message = $e->getMessage();
 			}
-			return new TemplateResponse('core', 'error', [
-				'errors' => [['error' => $this->l10n->t('Password reset is disabled')]]
-			],
+			$response = new TemplateResponse(
+				'core', 'error', [
+					'errors' => [['error' => $message]]
+				],
 				TemplateResponse::RENDER_AS_GUEST
 			);
+			$response->throttle();
+			return $response;
 		}
 		$this->initialState->provideInitialState('resetPasswordUser', $userId);
 		$this->initialState->provideInitialState('resetPasswordTarget',

tests/Core/Controller/LostControllerTest.php

@@ -53,6 +53,7 @@ class LostControllerTest extends TestCase {
 	private $defaults;
 	/** @var IConfig | MockObject */
 	private $config;
+	private string $lostPasswordLink = '';
 	/** @var IMailer | MockObject */
 	private $mailer;
 	/** @var IManager|MockObject */
@@ -93,11 +94,13 @@ class LostControllerTest extends TestCase {
 		$this->config = $this->createMock(IConfig::class);
 		$this->config->expects($this->any())
 			->method('getSystemValue')
-			->willReturnMap([
-				['secret', null, 'SECRET'],
-				['secret', '', 'SECRET'],
-				['lost_password_link', '', ''],
-			]);
+			->willReturnCallback(function (string $key, $default = '') {
+				return match ($key) {
+					'secret' => 'SECRET',
+					'lost_password_link' => $this->lostPasswordLink,
+					default => $default,
+				};
+			});
 		$this->l10n = $this->createMock(IL10N::class);
 		$this->l10n
 			->expects($this->any())
@@ -162,6 +165,29 @@ class LostControllerTest extends TestCase {
 		$this->assertEquals($expectedResponse, $response);
 	}
 
+	public function testResetFormTokenErrorWithDisabledLink(): void {
+		$this->lostPasswordLink = 'disabled';
+		$this->userManager->method('get')
+			->with('ValidTokenUser')
+			->willReturn($this->existingUser);
+		$this->verificationToken->expects($this->once())
+			->method('check')
+			->with('12345:MySecretToken', $this->existingUser, 'lostpassword', 'test@example.com')
+			->willThrowException(new InvalidTokenException(InvalidTokenException::TOKEN_NOT_FOUND));
+
+		$response = $this->lostController->resetform('12345:MySecretToken', 'ValidTokenUser');
+		$expectedResponse = new TemplateResponse('core',
+			'error',
+			[
+				'errors' => [
+					['error' => 'Password reset is disabled'],
+				]
+			],
+			'guest');
+		$expectedResponse->throttle();
+		$this->assertEquals($expectedResponse, $response);
+	}
+
 	public function testResetFormValidToken(): void {
 		$this->userManager->method('get')
 			->with('ValidTokenUser')