Add trusted type checks for global event handler attributes (#38718)

This only covers the global event handlers for now, while I figure out
which others we are missing. We don't seem to be missing the
WindowEventHandlers, but not sure where the others coming from.

Part of #36258

Signed-off-by: Tim van der Lippe <tvanderlippe@gmail.com>

components/script/dom/eventtarget.rs

@@ -68,6 +68,98 @@ use crate::dom::workerglobalscope::WorkerGlobalScope;
 use crate::realms::{InRealm, enter_realm};
 use crate::script_runtime::CanGc;
 
+/// <https://html.spec.whatwg.org/multipage/#event-handler-content-attributes>
+/// containing the values from
+/// <https://html.spec.whatwg.org/multipage/#globaleventhandlers>
+static CONTENT_EVENT_HANDLER_NAMES: [&str; 83] = [
+    "onabort",
+    "onauxclick",
+    "onbeforeinput",
+    "onbeforematch",
+    "onbeforetoggle",
+    "onblur",
+    "oncancel",
+    "oncanplay",
+    "oncanplaythrough",
+    "onchange",
+    "onclick",
+    "onclose",
+    "oncommand",
+    "oncontextlost",
+    "oncontextmenu",
+    "oncontextrestored",
+    "oncopy",
+    "oncuechange",
+    "oncut",
+    "ondblclick",
+    "ondrag",
+    "ondragend",
+    "ondragenter",
+    "ondragleave",
+    "ondragover",
+    "ondragstart",
+    "ondrop",
+    "ondurationchange",
+    "onemptied",
+    "onended",
+    "onerror",
+    "onfocus",
+    "onformdata",
+    "oninput",
+    "oninvalid",
+    "onkeydown",
+    "onkeypress",
+    "onkeyup",
+    "onload",
+    "onloadeddata",
+    "onloadedmetadata",
+    "onloadstart",
+    "onmousedown",
+    "onmouseenter",
+    "onmouseleave",
+    "onmousemove",
+    "onmouseout",
+    "onmouseover",
+    "onmouseup",
+    "onpaste",
+    "onpause",
+    "onplay",
+    "onplaying",
+    "onprogress",
+    "onratechange",
+    "onreset",
+    "onresize",
+    "onscroll",
+    "onscrollend",
+    "onsecuritypolicyviolation",
+    "onseeked",
+    "onseeking",
+    "onselect",
+    "onslotchange",
+    "onstalled",
+    "onsubmit",
+    "onsuspend",
+    "ontimeupdate",
+    "ontoggle",
+    "onvolumechange",
+    "onwaiting",
+    "onwebkitanimationend",
+    "onwebkitanimationiteration",
+    "onwebkitanimationstart",
+    "onwebkittransitionend",
+    "onwheel",
+    // https://drafts.csswg.org/css-animations/#interface-globaleventhandlers-idl
+    "onanimationend",
+    "onanimationiteration",
+    // https://drafts.csswg.org/css-transitions/#interface-globaleventhandlers-idl
+    "ontransitionrun",
+    "ontransitionend",
+    "ontransitioncancel",
+    // https://w3c.github.io/selection-api/#extensions-to-globaleventhandlers-interface
+    "onselectstart",
+    "onselectionchange",
+];
+
 #[derive(Clone, JSTraceable, MallocSizeOf, PartialEq)]
 #[allow(clippy::enum_variant_names)]
 pub(crate) enum CommonEventHandler {
@@ -956,6 +1048,11 @@ impl EventTarget {
             );
         }
     }
+
+    /// <https://html.spec.whatwg.org/multipage/#event-handler-content-attributes>
+    pub(crate) fn is_content_event_handler(name: &str) -> bool {
+        CONTENT_EVENT_HANDLER_NAMES.contains(&name)
+    }
 }
 
 impl EventTargetMethods<crate::DomTypeHolder> for EventTarget {

components/script/dom/trustedtypepolicyfactory.rs

@@ -20,6 +20,7 @@ use crate::dom::bindings::reflector::{DomGlobal, Reflector, reflect_dom_object};
 use crate::dom::bindings::root::{DomRoot, MutNullableDom};
 use crate::dom::bindings::str::DOMString;
 use crate::dom::csp::CspReporting;
+use crate::dom::eventtarget::EventTarget;
 use crate::dom::globalscope::GlobalScope;
 use crate::dom::trustedhtml::TrustedHTML;
 use crate::dom::trustedscript::TrustedScript;
@@ -120,8 +121,18 @@ impl TrustedTypePolicyFactory {
         // Step 1: Let data be null.
         //
         // We return the if directly
-        // Step 2: If attributeNs is null, and attribute is the name of an event handler content attribute, then:
-        // TODO(36258): look up event handlers
+        // Step 2: If attributeNs is null, « HTML namespace, SVG namespace, MathML namespace » contains
+        // element’s namespace, and attribute is the name of an event handler content attribute:
+        if attribute_namespace.is_none() &&
+            matches!(*element_namespace, ns!(html) | ns!(svg) | ns!(mathml)) &&
+            EventTarget::is_content_event_handler(attribute)
+        {
+            // Step 2.1. Return (Element, null, attribute, TrustedScript, "Element " + attribute).
+            return Some((
+                TrustedType::TrustedScript,
+                "Element ".to_owned() + attribute,
+            ));
+        }
         // Step 3: Find the row in the following table, where element is in the first column,
         // attributeNs is in the second column, and attribute is in the third column.
         // If a matching row is found, set data to that row.