Fix IDN domain name not being allowed

The filter_var function is unfortunately not perfect and doesn't support
domain with unicode as well as url with underscores. Replace usage with
a regex.

See https://bugs.php.net/search.php?cmd=display&search_for=FILTER_VALIDATE_URL

Closes #27906

Signed-off-by: Carl Schwan <carl@carlschwan.eu>

apps/oauth2/lib/Controller/SettingsController.php

@@ -81,7 +81,7 @@ public function __construct(string $appName,
 
 	public function addClient(string $name,
 							  string $redirectUri): JSONResponse {
-		if (filter_var($redirectUri, FILTER_VALIDATE_URL) === false) {
+		if (!\OCP\Util::isValidUrl($redirectUri)) {
 			return new JSONResponse(['message' => $this->l->t('Your redirect URL needs to be a full URL for example: https://yourdomain.com/path')], Http::STATUS_BAD_REQUEST);
 		}
 

apps/theming/lib/Controller/ThemingController.php

@@ -54,6 +54,7 @@
 use OCP\IRequest;
 use OCP\ITempManager;
 use OCP\IURLGenerator;
+use OCP\Util;
 
 /**
  * Class ThemingController
@@ -142,23 +143,23 @@ public function updateStylesheet($setting, $value) {
 				if (strlen($value) > 500) {
 					$error = $this->l10n->t('The given web address is too long');
 				}
-				if (!$this->isValidUrl($value)) {
+				if (!Util::isValidUrl($value)) {
 					$error = $this->l10n->t('The given web address is not a valid URL');
 				}
 				break;
 			case 'imprintUrl':
 				if (strlen($value) > 500) {
 					$error = $this->l10n->t('The given legal notice address is too long');
 				}
-				if (!$this->isValidUrl($value)) {
+				if (!Util::isValidUrl($value)) {
 					$error = $this->l10n->t('The given legal notice address is not a valid URL');
 				}
 				break;
 			case 'privacyUrl':
 				if (strlen($value) > 500) {
 					$error = $this->l10n->t('The given privacy policy address is too long');
 				}
-				if (!$this->isValidUrl($value)) {
+				if (!Util::isValidUrl($value)) {
 					$error = $this->l10n->t('The given privacy policy address is not a valid URL');
 				}
 				break;
@@ -199,14 +200,6 @@ public function updateStylesheet($setting, $value) {
 		);
 	}
 
-	/**
-	 * Check that a string is a valid http/https url
-	 */
-	private function isValidUrl(string $url): bool {
-		return ((strpos($url, 'http://') === 0 || strpos($url, 'https://') === 0) &&
-			filter_var($url, FILTER_VALIDATE_URL) !== false);
-	}
-
 	/**
 	 * @return DataResponse
 	 * @throws NotPermittedException

apps/theming/lib/ThemingDefaults.php

@@ -203,7 +203,7 @@ public function getShortFooter() {
 		$divider = '';
 		foreach ($links as $link) {
 			if ($link['url'] !== ''
-				&& filter_var($link['url'], FILTER_VALIDATE_URL)
+				&& \OCP\Util::isValidUrl($link['url'])
 			) {
 				$legalLinks .= $divider . '<a href="' . $link['url'] . '" class="legal" target="_blank"' .
 					' rel="noreferrer noopener">' . $link['text'] . '</a>';

lib/private/Setup.php

@@ -474,7 +474,7 @@ private static function findWebRoot(SystemConfig $config): string {
 			if ($webRoot === '') {
 				throw new InvalidArgumentException('overwrite.cli.url is empty');
 			}
-			if (!filter_var($webRoot, FILTER_VALIDATE_URL)) {
+			if (!\OCP\Util::isValidUrl($webRoot)) {
 				throw new InvalidArgumentException('invalid value for overwrite.cli.url');
 			}
 			$webRoot = rtrim(parse_url($webRoot, PHP_URL_PATH), '/');

lib/public/Util.php

@@ -513,4 +513,16 @@ public static function needUpgrade() {
 		}
 		return self::$needUpgradeCache;
 	}
+
+	/**
+	 * Checks whether the given URL is valid. This function should be
+	 * used instead of filter_var($url, FILTER_VALIDATE_URL) since it
+	 * handles idn urls too.
+	 *
+	 * @return bool true if the url is valid, false otherwise.
+	 * @since 23.0.0
+	 */
+	public static function isValidUrl(string $url): bool {
+		return filter_var(idn_to_ascii($url), FILTER_VALIDATE_URL) !== false;
+	}
 }