Fix: Malformed MKV could cause an infinite loop

Co-authored-by: Sindre Sorhus <[email protected]>
sindresorhus · Jul 21, 2022 · d868356 · d868356
1 parent 3b08ab1
commit d868356
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Showing 3 changed files with 6 additions and 1 deletion.
diff --git a/core.js b/core.js
@@ -681,7 +681,7 @@ async function _fromTokenizer(tokenizer) {
 			let mask = 0x80;
 			let ic = 0; // 0 = A, 1 = B, 2 = C, 3 = D
 
-			while ((msb & mask) === 0) {
+			while ((msb & mask) === 0 && mask !== 0) {
 				++ic;
 				mask >>= 1;
 			}

diff --git a/fixture/fixture-corrupt.mkv b/fixture/fixture-corrupt.mkv
diff --git a/test.js b/test.js
@@ -543,3 +543,8 @@ test('odd file sizes', async t => {
 		await t.notThrowsAsync(FileType.fromStream(stream), `fromStream: File size: ${size} bytes`);
 	}
 });
+
+test('corrupt MKV throws', async t => {
+	const filePath = path.join(__dirname, 'fixture/fixture-corrupt.mkv');
+	await t.throwsAsync(FileType.fromFile(filePath), {message: /out of range/});
+});