Merge pull request #427 from XmiliaH/skip-transformer

Skip transformer in trivial cases
patriksimek · Jul 5, 2022 · f1167de · f1167de
2 parents e3e573f + 4392f5a
commit f1167de
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Showing 2 changed files with 10 additions and 6 deletions.
diff --git a/lib/transformer.js b/lib/transformer.js
@@ -51,6 +51,10 @@ function transformer(args, body, isAsync, isGenerator, filename) {
 	let argsOffset;
 	if (args === null) {
 		code = body;
+		// Note: Keywords are not allows to contain u escapes
+		if (!/\b(?:catch|import|async)\b/.test(code)) {
+			return {__proto__: null, code, hasAsync: false};
+		}
 	} else {
 		code = isAsync ? '(async function' : '(function';
 		if (isGenerator) code += '*';

diff --git a/test/vm.js b/test/vm.js
@@ -663,12 +663,12 @@ describe('VM', () => {
 
 	it('internal state attack', () => {
 		const vm2 = new VM();
-		assert.throws(() => vm2.run(`${INTERNAL_STATE_NAME}=1;`), /Use of internal vm2 state variable/);
-		assert.throws(() => vm2.run(`const ${INTERNAL_STATE_NAME} = {};`), /Use of internal vm2 state variable/);
-		assert.throws(() => vm2.run(`var ${INTERNAL_STATE_NAME} = {};`), /Use of internal vm2 state variable/);
-		assert.throws(() => vm2.run(`let ${INTERNAL_STATE_NAME} = {};`), /Use of internal vm2 state variable/);
-		assert.throws(() => vm2.run(`class ${INTERNAL_STATE_NAME} {};`), /Use of internal vm2 state variable/);
-		assert.throws(() => vm2.run(`function ${INTERNAL_STATE_NAME} () {};`), /Use of internal vm2 state variable/);
+		assert.throws(() => vm2.run(`${INTERNAL_STATE_NAME}="async";`), /Use of internal vm2 state variable/);
+		assert.throws(() => vm2.run(`const ${INTERNAL_STATE_NAME} = "async";`), /Use of internal vm2 state variable/);
+		assert.throws(() => vm2.run(`var ${INTERNAL_STATE_NAME} = "async";`), /Use of internal vm2 state variable/);
+		assert.throws(() => vm2.run(`let ${INTERNAL_STATE_NAME} = "async";`), /Use of internal vm2 state variable/);
+		assert.throws(() => vm2.run(`class ${INTERNAL_STATE_NAME} {}; // async`), /Use of internal vm2 state variable/);
+		assert.throws(() => vm2.run(`function ${INTERNAL_STATE_NAME} () {}; // async`), /Use of internal vm2 state variable/);
 	});
 
 	it('buffer attack', () => {