Interception of screen capture.

svc/minuette.js

@@ -1,10 +1,12 @@
 "use strict";
 import {ics} from "./ics.js";
 import {fakeNative} from "./minuette/fakeNative.js";
-import {getCSSSelector} from "./minuette/cssSelector.js"
+import {getCSSSelector} from "./minuette/cssSelector.js";
 import {getRandom} from "./minuette/getRandom.js";
-import {getEventFamily, getEventData} from "./minuette/eventData.js"
+import {getEventFamily, getEventData} from "./minuette/eventData.js";
+import {fakeScreen, fakeCamera} from "./minuette/fakeStream.js";
 self.blacklistEvent = ["visibilitychange"];
+self.fakeScreenVideo = undefined;
 {
 	// Constants
 	const selectorSkip = ["id", "class"],
@@ -52,8 +54,39 @@ self.blacklistEvent = ["visibilitychange"];
 	fakeNative(HTMLElement.prototype.addEventListener);
 	HTMLElement.prototype.addEventListener = fakeAddEl;
 	document.addEventListener = fakeAddEl;
-	// Hijack several document APIs
-	let realDocument = self.document;
+	// Hijack screen reading
+	let realScreen = self.screen, fakeScreenWidth, fakeScreenHeight;
+	self.screen = new Proxy(self.screen, {get: function (obj, prop) {
+		switch (prop) {
+			case "availHeight":
+			case "height": {
+				return fakeScreenHeight;
+				break;
+			};
+			case "availWidth":
+			case "width": {
+				return fakeScreenWidth;
+				break;
+			};
+			case "orientation": {
+				return new Proxy(realScreen.orientation, {get: function (obj, prop) {
+					if (prop == "type") {
+						return (screen.width / screen.height < 1 ? "portrait" : "landscape");
+					} else {
+						return obj[prop];
+					};
+				}});
+				break;
+			};
+			default: {
+				return obj[prop];
+			};
+		};
+	}});
+	/*screen.orientation = */
+	let navMedDev = navigator.mediaDevices,
+	getDispMed = navMedDev.getDisplayMedia,
+	getUserMed = navMedDev.getUserMedia;
 	// Extension channel message
 	let extChannel = new BroadcastChannel("-ReplaceMeWithSomethingUnique-");
 	extChannel.onmessage = function (msg) {
@@ -72,5 +105,62 @@ self.blacklistEvent = ["visibilitychange"];
 			};
 		};
 	};
+	// Hijack display capture
+	navigator.mediaDevices.getDisplayMedia = async function () {
+		let stream;
+		try {
+			stream = await getDispMed.apply(navMedDev, arguments);
+		} catch (err) {
+			extChannel.postMessage({e: "getDisplay", success: false});
+			throw(err);
+		};
+		// Hijack stream
+		let inFocus = true, captureExhaust = 0;
+		let fakeVideoSource = document.createElement("video");
+		fakeVideoSource.srcObject = stream;
+		fakeVideoSource.muted = true;
+		fakeVideoSource.autoplay = true;
+		fakeVideoSource.style = "display: none";
+		addEL.apply(document, ["blur", function () {
+			inFocus = false;
+			captureExhaust = 2;
+			fakeVideoSource.pause();
+			ics.debug("Window lost focus.");
+		}]);
+		addEL.apply(document, ["focus", function () {
+			inFocus = true;
+			fakeVideoSource.play();
+			captureExhaust = 5;
+			ics.debug("Window regain focus.");
+		}]);
+		document.body.appendChild(fakeVideoSource);
+		let fakeVideoCanvas = document.createElement("canvas");
+		fakeVideoCanvas.width = screen.width;
+		fakeVideoCanvas.height = screen.height;
+		fakeVideoCanvas.style = "display: none";
+		document.body.appendChild(fakeVideoCanvas);
+		let fakeCanvasContext = fakeVideoCanvas.getContext("2d");
+		fakeCanvasContext.fillStyle = "#777";
+		fakeCanvasContext.fillRect(0, 0, screen.width, screen.height);
+		addEL.apply(fakeVideoSource, ["playing", function () {
+			fakeScreenWidth = fakeVideoSource.videoWidth,
+			fakeScreenHeight = fakeVideoSource.videoHeight;
+			fakeVideoCanvas.width = fakeVideoSource.videoWidth;
+			fakeVideoCanvas.height = fakeVideoSource.videoHeight;
+			fakeCanvasContext.drawImage(fakeVideoSource, 0, 0);
+		}]);
+		let proxyScreen = setInterval(function () {
+			if (!document.hidden && inFocus && !fakeVideoSource.paused) {
+				if (captureExhaust < 1) {
+					fakeCanvasContext.drawImage(fakeVideoSource, 0, 0);
+				} else {
+					captureExhaust --;
+				};
+			};
+		}, 50);
+		let newStream = fakeVideoCanvas.captureStream(60);
+		extChannel.postMessage({e: "getDisplay", success: true, stream: stream.id, task: proxyScreen});
+		return newStream;
+	};
 };
 ics.debug("Minuette launched.");

svc/minuette/fakeStream.js

@@ -0,0 +1,21 @@
+"use strict";
+let fakeScreenGetter = function (obj, prop) {
+	if (prop != "label") {
+		return obj[prop];
+	} else {
+		return "Primary Monitor"; // This may change due to language or browser. This is on Firefox.
+	};
+};
+// I'm a bummer
+let fakeScreen = function (stream) {
+	stream.forEach(function (e, i, a) {
+		a[i] = new Proxy(e, fakeScreenGetter);
+	});
+	return stream;
+};
+let fakeCamera = function (stream) {};
+
+export {
+	fakeScreen,
+	fakeCamera
+};