fs: validate path in fs.exists{Sync}

PR-URL: https://github.com/nodejs/node/pull/17852
Refs: https://github.com/nodejs/node/pull/17667
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Matteo Collina <matteo.collina@gmail.com>

lib/fs.js

@@ -340,6 +340,10 @@ fs.accessSync = function(path, mode) {
 fs.exists = function(path, callback) {
   if (handleError((path = getPathFromURL(path)), cb))
     return;
+  if (typeof path !== 'string' && !(path instanceof Buffer)) {
+    throw new errors.TypeError('ERR_INVALID_ARG_TYPE', 'path',
+                               ['string', 'Buffer', 'URL']);
+  }
   if (!nullCheck(path, cb)) return;
   var req = new FSReqWrap();
   req.oncomplete = cb;
@@ -361,6 +365,9 @@ Object.defineProperty(fs.exists, internalUtil.promisify.custom, {
 fs.existsSync = function(path) {
   try {
     handleError((path = getPathFromURL(path)));
+    if (typeof path !== 'string' && !(path instanceof Buffer)) {
+      return false;
+    }
     nullCheck(path);
     binding.stat(pathModule.toNamespacedPath(path));
     return true;

test/parallel/test-fs-exists.js

@@ -42,3 +42,14 @@ fs.exists(new URL('https://foo'), common.mustCall(function(y) {
 
 assert(fs.existsSync(f));
 assert(!fs.existsSync(`${f}-NO`));
+
+common.expectsError(
+  () => { fs.exists(() => {}); },
+  {
+    code: 'ERR_INVALID_ARG_TYPE',
+    message: 'The "path" argument must be one of type string, Buffer, or URL',
+    type: TypeError
+  }
+);
+
+assert(!fs.existsSync());