mrwonko · December 29, 2024 11:44
diff --git a/index.html b/index.html
 <!DOCTYPE html>
 <html lang="en-US">

 <head>
    <title>Directory Access Proof-of-Concept</title>
    <script>
        const trailerSignature = new Uint8Array([0x50, 0x4b, 0x05, 0x06]); // "End of Central Directory" record
        const showPicker = async () => {
            // find assets0.pk3

            const selectedDirHandle = await showDirectoryPicker();
            let baseDirHandle = selectedDirHandle;
            let assets0Handle;
            try {
                assets0Handle = await selectedDirHandle.getFileHandle("assets0.pk3");
            } catch (e) {
                if (e.name === "NotFoundError") {
                    try {
                        baseDirHandle = await selectedDirHandle.getDirectoryHandle("base");
                        assets0Handle = await baseDirHandle.getFileHandle("assets0.pk3")
                    } catch (e) {
                        if (e.name === "NotFoundError") {
                            alert("found neither assets0.pk3 nor base/assets0.pk3");
                            return;
                        } else {
                            throw e;
                        }
                    }
                } else {
                    throw e;
                }
            }
            const assets0File = await assets0Handle.getFile();
            console.log(`assets0.pk3 size: ${assets0File.size} bytes`);

            // read End of Central Directory record

            // the .zip trailer contains a variable-length comment, so we have to make sure we read enough to get all of it
            const minTrailerSize = 22;
            // comment length is stored in 2 bytes
            const maxCommentSize = (1 << 16) - 1;
            const maxTrailerSize = minTrailerSize + maxCommentSize;
            const trailerSlice = assets0File.slice(-maxTrailerSize);
            const trailerArrayBuffer = await trailerSlice.arrayBuffer();
            let trailerUint8Array = new Uint8Array(trailerArrayBuffer);
            let trailerStart; // relative to -maxTrailerSize
            for (let candidate = trailerUint8Array.length - minTrailerSize; candidate >= 0; candidate--) {
                if (trailerUint8Array[candidate + 0] === trailerSignature[0] &&
                    trailerUint8Array[candidate + 1] === trailerSignature[1] &&
                    trailerUint8Array[candidate + 2] === trailerSignature[2] &&
                    trailerUint8Array[candidate + 3] === trailerSignature[3]) {
                    trailerStart = candidate;
                    break;
                }
            }
            if (trailerStart === undefined) {
                alert("could not find a valid zip trailer in assets0.pk3");
                return;
            }
            console.log(`found end of central directory record ${-maxTrailerSize + trailerStart} bytes from end of assets0.pk3`);
            trailerUint8Array = trailerUint8Array.slice(trailerStart);

            // read first Central Directory entry

            const centralDirectorySize = (trailerUint8Array[0xC] << 0) | (trailerUint8Array[0xD] << 8) | (trailerUint8Array[0xE] << 16) | (trailerUint8Array[0xF] << 24);
            const centralDirectoryStart = (trailerUint8Array[0x10] << 0) | (trailerUint8Array[0x11] << 8) | (trailerUint8Array[0x12] << 16) | (trailerUint8Array[0x13] << 24);
            const centralDirectorySlice = assets0File.slice(centralDirectoryStart, centralDirectoryStart + centralDirectorySize);
            const centralDirectoryArrayBuffer = await centralDirectorySlice.arrayBuffer();
            const centralDirectoryUint8Array = new Uint8Array(centralDirectoryArrayBuffer);
            const fileNameLength = (centralDirectoryUint8Array[0x1C] << 0) | (centralDirectoryUint8Array[0x1D] << 8);
            const fileNameOffset = 0x2e;
            let fileName = "";
            for (let i = fileNameOffset; i < fileNameOffset + fileNameLength; i++) {
                fileName += String.fromCharCode(centralDirectoryUint8Array[i]);
            }
            const externalAttributes = (centralDirectoryUint8Array[0x26] << 0) | (centralDirectoryUint8Array[0x27] << 8) | (centralDirectoryUint8Array[0x28] << 16) | (centralDirectoryUint8Array[0x29] << 24);
            const isDir = Boolean(externalAttributes & 0x10);
            alert(`the first entry in assets0.pk3 is ${fileName}, it's a ${isDir ? "directory" : "file"}`);
        };
    </script>
 </head>

 <body>
    <button type="button" onclick="showPicker()">select Jedi Academy folder</button>
 </body>

 </html>
	<!DOCTYPE html>
	<html lang="en-US">

	<head>
	<title>Directory Access Proof-of-Concept</title>
	<script>
	const trailerSignature = new Uint8Array([0x50, 0x4b, 0x05, 0x06]); // "End of Central Directory" record
	const showPicker = async () => {
	// find assets0.pk3

	const selectedDirHandle = await showDirectoryPicker();
	let baseDirHandle = selectedDirHandle;
	let assets0Handle;
	try {
	assets0Handle = await selectedDirHandle.getFileHandle("assets0.pk3");
	} catch (e) {
	if (e.name === "NotFoundError") {
	try {
	baseDirHandle = await selectedDirHandle.getDirectoryHandle("base");
	assets0Handle = await baseDirHandle.getFileHandle("assets0.pk3")
	} catch (e) {
	if (e.name === "NotFoundError") {
	alert("found neither assets0.pk3 nor base/assets0.pk3");
	return;
	} else {
	throw e;
	}
	}
	} else {
	throw e;
	}
	}
	const assets0File = await assets0Handle.getFile();
	console.log(`assets0.pk3 size: ${assets0File.size} bytes`);

	// read End of Central Directory record

	// the .zip trailer contains a variable-length comment, so we have to make sure we read enough to get all of it
	const minTrailerSize = 22;
	// comment length is stored in 2 bytes
	const maxCommentSize = (1 << 16) - 1;
	const maxTrailerSize = minTrailerSize + maxCommentSize;
	const trailerSlice = assets0File.slice(-maxTrailerSize);
	const trailerArrayBuffer = await trailerSlice.arrayBuffer();
	let trailerUint8Array = new Uint8Array(trailerArrayBuffer);
	let trailerStart; // relative to -maxTrailerSize
	for (let candidate = trailerUint8Array.length - minTrailerSize; candidate >= 0; candidate--) {
	if (trailerUint8Array[candidate + 0] === trailerSignature[0] &&
	trailerUint8Array[candidate + 1] === trailerSignature[1] &&
	trailerUint8Array[candidate + 2] === trailerSignature[2] &&
	trailerUint8Array[candidate + 3] === trailerSignature[3]) {
	trailerStart = candidate;
	break;
	}
	}
	if (trailerStart === undefined) {
	alert("could not find a valid zip trailer in assets0.pk3");
	return;
	}
	console.log(`found end of central directory record ${-maxTrailerSize + trailerStart} bytes from end of assets0.pk3`);
	trailerUint8Array = trailerUint8Array.slice(trailerStart);

	// read first Central Directory entry

	const centralDirectorySize = (trailerUint8Array[0xC] << 0) \| (trailerUint8Array[0xD] << 8) \| (trailerUint8Array[0xE] << 16) \| (trailerUint8Array[0xF] << 24);
	const centralDirectoryStart = (trailerUint8Array[0x10] << 0) \| (trailerUint8Array[0x11] << 8) \| (trailerUint8Array[0x12] << 16) \| (trailerUint8Array[0x13] << 24);
	const centralDirectorySlice = assets0File.slice(centralDirectoryStart, centralDirectoryStart + centralDirectorySize);
	const centralDirectoryArrayBuffer = await centralDirectorySlice.arrayBuffer();
	const centralDirectoryUint8Array = new Uint8Array(centralDirectoryArrayBuffer);
	const fileNameLength = (centralDirectoryUint8Array[0x1C] << 0) \| (centralDirectoryUint8Array[0x1D] << 8);
	const fileNameOffset = 0x2e;
	let fileName = "";
	for (let i = fileNameOffset; i < fileNameOffset + fileNameLength; i++) {
	fileName += String.fromCharCode(centralDirectoryUint8Array[i]);
	}
	const externalAttributes = (centralDirectoryUint8Array[0x26] << 0) \| (centralDirectoryUint8Array[0x27] << 8) \| (centralDirectoryUint8Array[0x28] << 16) \| (centralDirectoryUint8Array[0x29] << 24);
	const isDir = Boolean(externalAttributes & 0x10);
	alert(`the first entry in assets0.pk3 is ${fileName}, it's a ${isDir ? "directory" : "file"}`);
	};
	</script>
	</head>

	<body>
	<button type="button" onclick="showPicker()">select Jedi Academy folder</button>
	</body>

	</html>