add testcase for GR-20862

Author: wirthi

graal-js/src/com.oracle.truffle.js.scriptengine.test/src/com/oracle/truffle/js/scriptengine/test/GR20862.java

@@ -0,0 +1,89 @@
+/*
+ * Copyright (c) 2020, 2020, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * The Universal Permissive License (UPL), Version 1.0
+ *
+ * Subject to the condition set forth below, permission is hereby granted to any
+ * person obtaining a copy of this software, associated documentation and/or
+ * data (collectively the "Software"), free of charge and under any and all
+ * copyright rights in the Software, and any and all patent rights owned or
+ * freely licensable by each licensor hereunder covering either (i) the
+ * unmodified Software as contributed to or provided by such licensor, or (ii)
+ * the Larger Works (as defined below), to deal in both
+ *
+ * (a) the Software, and
+ *
+ * (b) any piece of software and/or hardware listed in the lrgrwrks.txt file if
+ * one is included with the Software each a "Larger Work" to which the Software
+ * is contributed by such licensors),
+ *
+ * without restriction, including without limitation the rights to copy, create
+ * derivative works of, display, perform, and distribute the Software and make,
+ * use, sell, offer for sale, import, export, have made, and have sold the
+ * Software and the Larger Work(s), and to sublicense the foregoing rights on
+ * either these or other terms.
+ *
+ * This license is subject to the following condition:
+ *
+ * The above copyright notice and either this complete permission notice or at a
+ * minimum a reference to the UPL must be included in all copies or substantial
+ * portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+package com.oracle.truffle.js.scriptengine.test;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertTrue;
+
+import javax.script.ScriptException;
+
+import org.graalvm.polyglot.PolyglotException;
+import org.junit.Test;
+
+import com.oracle.truffle.js.scriptengine.GraalJSScriptEngine;
+
+public class GR20862 {
+
+    private static final String INSECURE_SCRIPTENGINE_ACCESS_SYSTEM_PROPERTY = "graaljs.insecure-scriptengine-access";
+
+    private static void tryAccessingHost(boolean allowHostAccess) {
+        System.setProperty(INSECURE_SCRIPTENGINE_ACCESS_SYSTEM_PROPERTY, allowHostAccess ? "true" : "false");
+        try (GraalJSScriptEngine engine = GraalJSScriptEngine.create()) {
+            engine.put("tester", new Tester());
+            String src = "tester.ret42();";
+            Object result = engine.eval(src);
+
+            // when access is allowed, expect correct result
+            assertTrue(allowHostAccess);
+            assertEquals(42, result);
+        } catch (ScriptException ex) {
+            // when access is not allowed, expect PolyglotException
+            assertFalse(allowHostAccess);
+            assertTrue(ex.getCause() instanceof PolyglotException);
+        }
+    }
+
+    public static class Tester {
+        public int ret42() {
+            return 42;
+        }
+    }
+
+    @Test
+    public void testHostAccessBypass() {
+        // try twice to avoid caching of engine with wrong setup
+        tryAccessingHost(false);
+        tryAccessingHost(true);
+        tryAccessingHost(false);
+        tryAccessingHost(true);
+    }
+}