N°4368 Fix CORB blocking regression (#598)

Don't send X-Content-Type-Options HTTP header for certain WebPage impl to workaround CORB blocking
To disable globally this new behavior introduced in 9865bf07, set the `security.enable_header_xcontent_type_options` config parameter to false

Thanks @Molkobain for the review !

application/ajaxwebpage.class.inc.php

@@ -51,6 +51,16 @@ class ajax_page extends WebPage implements iTabbedPage
 		utils::InitArchiveMode();
 	}
 
+	/**
+	 * Disabling sending the header so that resource won't be blocked by CORB. See parent method documentation.
+	 * @return void
+	 * @since 2.7.10 3.0.4 3.1.2 3.2.0 N°4368 method creation
+	 */
+	public function add_xcontent_type_options()
+	{
+		// Nothing to do !
+	}
+
 	/**
 	 * @inheritDoc
 	 * @throws \Exception

application/webpage.class.inc.php

@@ -495,13 +495,12 @@ class WebPage implements Page
 	}
 
 	/**
-	 * @param string|null $sHeaderValue for example `SAMESITE`. If null will set the header using the config parameter value.
+	 * @param string|null $sHeaderValue for example `SAMESITE`. If null will set the header using the `security_header_xframe` config parameter value.
 	 *
 	 * @since 2.7.3 3.0.0 N°3416
-	 * @uses security_header_xframe config parameter
 	 * @uses \utils::GetConfig()
 	 *
-	 * @link https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/X-Frame-Options
+	 * @link https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/X-Frame-Options HTTP header MDN documentation
 	 */
 	public function add_xframe_options($sHeaderValue = null)
 	{
@@ -513,13 +512,34 @@ class WebPage implements Page
 	}
 
 	/**
+	 * Warning : this header will trigger the Cross-Origin Read Blocking (CORB) protection for some mime types (HTML, XML except SVG, JSON, text/plain)
+	 * In consequence some children pages will override this method.
+	 *
+	 * Sending header can be disabled globally using the `security.enable_header_xcontent_type_options` optional config parameter.
+	 *
 	 * @return void
 	 * @since 2.7.10 3.0.4 3.1.2 3.2.0 N°4368 method creation
 	 *
-	 * @link https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/X-Content-Type-Options
+	 * @link https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/X-Content-Type-Options HTTP header MDN documentation
+	 * @link https://chromium.googlesource.com/chromium/src/+/master/services/network/cross_origin_read_blocking_explainer.md#determining-whether-a-response-is-corb_protected "Determining whether a response is CORB-protected"
 	 */
 	public function add_xcontent_type_options()
 	{
+		try {
+			$oConfig = utils::GetConfig();
+		} catch (ConfigException|CoreException $e) {
+			$oConfig = null;
+		}
+		if (is_null($oConfig)) {
+			$bSendXContentTypeOptionsHttpHeader = true;
+		} else {
+			$bSendXContentTypeOptionsHttpHeader = $oConfig->Get('security.enable_header_xcontent_type_options');
+		}
+
+		if ($bSendXContentTypeOptionsHttpHeader === false) {
+			return;
+		}
+
 		$this->add_header('X-Content-Type-Options: nosniff');
 	}
 

application/xmlpage.class.inc.php

@@ -48,6 +48,16 @@ class XMLPage extends WebPage
 		$this->add_header("Content-location: export.xml");
 	}
 
+	/**
+	 * Disabling sending the header so that resource won't be blocked by CORB. See parent method documentation.
+	 * @return void
+	 * @since 2.7.10 3.0.4 3.1.2 3.2.0 N°4368 method creation
+	 */
+	public function add_xcontent_type_options()
+	{
+		// Nothing to do !
+	}
+
 	public function output()
 	{
 		if (!$this->m_bPassThrough)

core/config.class.inc.php

@@ -1320,6 +1320,14 @@ class Config
 			'source_of_value' => '',
 			'show_in_conf_sample' => false,
 		],
+		'security.enable_header_xcontent_type_options' => [
+			'type' => 'bool',
+			'description' => 'If set to false, iTop will stop sending the X-Content-Type-Options HTTP header. This header could trigger CORB protection on certain resources (JSON, XML, HTML, text) therefore blocking them.',
+			'default' => true,
+			'value' => '',
+			'source_of_value' => '',
+			'show_in_conf_sample' => false,
+		],
 		'behind_reverse_proxy' => [
 			'type' => 'bool',
 			'description' => 'If true, then proxies custom header (X-Forwarded-*) are taken into account. Use only if the webserver is not publicly accessible (reachable only by the reverse proxy)',