fs: improve fchmod{Sync} validation

This commit validates the fd parameters to fs.fchmod{Sync} as
int32s instead of uint32s because they are ints in the binding
layer.

PR-URL: #20588
Fixes: #20498
Reviewed-By: Joyee Cheung <joyeec9h3@gmail.com>
Reviewed-By: Weijia Wang <starkwang@126.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Matteo Collina <matteo.collina@gmail.com>

Backport-PR-URL: #21172

lib/fs.js

@@ -86,6 +86,7 @@ const {
   isUint32,
   validateAndMaskMode,
   validateInteger,
+  validateInt32,
   validateUint32
 } = require('internal/validators');
 
@@ -1054,7 +1055,7 @@ fs.unlinkSync = function(path) {
 };
 
 fs.fchmod = function(fd, mode, callback) {
-  validateUint32(fd, 'fd');
+  validateInt32(fd, 'fd', 0);
   mode = validateAndMaskMode(mode, 'mode');
   callback = makeCallback(callback);
 
@@ -1064,7 +1065,7 @@ fs.fchmod = function(fd, mode, callback) {
 };
 
 fs.fchmodSync = function(fd, mode) {
-  validateUint32(fd, 'fd');
+  validateInt32(fd, 'fd', 0);
   mode = validateAndMaskMode(mode, 'mode');
   const ctx = {};
   binding.fchmod(fd, mode, undefined, ctx);

test/parallel/test-fs-fchmod.js

@@ -35,12 +35,21 @@ const fs = require('fs');
   const errObj = {
     code: 'ERR_OUT_OF_RANGE',
     name: 'RangeError [ERR_OUT_OF_RANGE]',
-    message: 'The value of "fd" is out of range. It must be >= 0 && < ' +
-             `${2 ** 32}. Received ${input}`
+    message: 'The value of "fd" is out of range. It must be >= 0 && <= ' +
+             `2147483647. Received ${input}`
   };
   assert.throws(() => fs.fchmod(input), errObj);
   assert.throws(() => fs.fchmodSync(input), errObj);
-  errObj.message = errObj.message.replace('fd', 'mode');
+});
+
+[-1, 2 ** 32].forEach((input) => {
+  const errObj = {
+    code: 'ERR_OUT_OF_RANGE',
+    name: 'RangeError [ERR_OUT_OF_RANGE]',
+    message: 'The value of "mode" is out of range. It must be >= 0 && < ' +
+             `4294967296. Received ${input}`
+  };
+
   assert.throws(() => fs.fchmod(1, input), errObj);
   assert.throws(() => fs.fchmodSync(1, input), errObj);
 });