Fix typed array subclasses in crypto.getRandomValues()

Closes #3395.

lib/jsdom/living/crypto/Crypto-impl.js

@@ -11,11 +11,7 @@ class CryptoImpl {
 
   // https://w3c.github.io/webcrypto/#Crypto-method-getRandomValues
   getRandomValues(array) {
-    // Note: this rejects Float32Array, Float64Array and DataView.
-    //
-    // We perform "instance tests" by comparing `array.constructor.name` so
-    // that the tests will be successful across realms.
-    const typeName = array.constructor.name;
+    const typeName = getTypedArrayTypeName(array);
     if (!(typeName === "Int8Array" ||
         typeName === "Uint8Array" ||
         typeName === "Uint8ClampedArray" ||
@@ -38,10 +34,30 @@ class CryptoImpl {
         "QuotaExceededError"
       ]);
     }
-
     nodeCrypto.randomFillSync(array);
     return array;
   }
 }
 
 exports.implementation = CryptoImpl;
+
+// See #3395. Subclasses of TypedArrays should properly work, but we can't rely
+// on instanceof because Uint8Array may be different across different windows -
+// which can happen in JSDOM when running { runScripts: "dangerously" }. As a
+// solution, we imitate the behavior of instanceof by walking the proottype
+// chain.
+function getTypedArrayTypeName(array) {
+  const target = array.constructor;
+  const chain = [target.name];
+  let proto = Object.getPrototypeOf(target);
+  while (proto) {
+    chain.push(proto.name);
+    proto = Object.getPrototypeOf(proto);
+  }
+
+  while (chain.length > 0 && chain[chain.length - 1] !== "TypedArray") {
+    chain.pop();
+  }
+  chain.reverse();
+  return chain[1];
+}

test/web-platform-tests/to-upstream/WebCryptoAPI/getRandomValues-BufferSource-subclasses.any.js

@@ -0,0 +1,22 @@
+"use strict";
+
+const arrays = [
+  "Int8Array",
+  "Int16Array",
+  "Int32Array",
+  "BigInt64Array",
+  "Uint8Array",
+  "Uint8ClampedArray",
+  "Uint16Array",
+  "Uint32Array",
+  "BigUint64Array"
+];
+
+for (const array of arrays) {
+  const ctor = globalThis[array];
+  test(() => {
+    class Buffer extends ctor {}
+    // Must not throw for the test to pass
+    self.crypto.getRandomValues(new Buffer(256));
+  }, "Subclass of " + array);
+}