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if (typeof exportFunction === "function") ns.on("capabilities", event => {
debug("WebGL Hook", document.URL, document.documentElement && document.documentElement.innerHTML, ns.capabilities); // DEV_ONLY
if (ns.allows("webgl")) return;
// win: window object to modify.
// modifyTarget: callback to function that modifies the desired properties
// or methods. Callback must take target window as argument.
function modifyWindow(win, modifyTarget) {
try {
modifyTarget(win);
modifyWindowOpenMethod(win, modifyTarget);
modifyFramingElements(win, modifyTarget);
} catch (e) {
if (e instanceof DOMException && e.name === "SecurityError") {
// In case someone tries to access SOP restricted window.
// We can just ignore this.
} else throw e;
}
}
function modifyWindowOpenMethod(win, modifyTarget) {
let windowOpen = win.wrappedJSObject ? win.wrappedJSObject.open : win.open;
exportFunction(function(...args) {
let newWin = windowOpen.call(this, ...args);
if (newWin) modifyWindow(newWin, modifyTarget);
return newWin;
}, win, {defineAs: "open"});
}
function modifyFramingElements(win, modifyTarget) {
for (let property of ["contentWindow", "contentDocument"]) {
for (let interface of ["Frame", "IFrame", "Object"]) {
let proto = win[`HTML${interface}Element`].prototype;
modifyContentProperties(proto, property, modifyTarget)
}
}
}
function modifyContentProperties(proto, property, modifyTarget) {
let descriptor = Object.getOwnPropertyDescriptor(proto, property);
let origGetter = descriptor.get;
let replacementFn;
if (property === "contentWindow") { replacementFn = function() {
let win = origGetter.call(this);
if (win) modifyWindow(win, modifyTarget);
return win;
}}
if (property === "contentDocument") { replacementFn = function() {
let document = origGetter.call(this);
if (document && document.defaultView) modifyWindow(document.defaultView, modifyTarget);
return document;
}}
descriptor.get = exportFunction(replacementFn, proto, {defineAs: `get $property`});
let wrappedProto = proto.wrappedJSObject || proto;
Object.defineProperty(wrappedProto, property, descriptor);
}
//
function modifyGetContext(win) {
let proto = win.HTMLCanvasElement.prototype;
let getContext = proto.getContext;
exportFunction(function(type, ...rest) {
if (type && type.toLowerCase().includes("webgl")) {
let request = {
id: "noscript-webgl",
type: "webgl",
url: document.URL,
documentUrl: document.URL,
embeddingDocument: true,
};
seen.record({policyType: "webgl", request, allowed: false});
try {
let ph = PlaceHolder.create("webgl", request);
ph.replace(this);
PlaceHolder.listen();
} catch (e) {
error(e);
}
notifyPage();
return {};
}
return getContext.call(this, type, ...rest);
}, proto, {defineAs: "getContext"});
}
modifyWindow(window, modifyGetContext);
});
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