[v10.x backport] fs: improve truncate length validation

lib/fs.js

@@ -85,7 +85,7 @@ const {
 } = require('internal/constants');
 const {
   isUint32,
-  validateInt32,
+  validateInteger,
   validateUint32
 } = require('internal/validators');
 
@@ -746,6 +746,7 @@ fs.truncate = function(path, len, callback) {
     len = 0;
   }
 
+  validateInteger(len, 'len');
   callback = maybeCallback(callback);
   fs.open(path, 'r+', function(er, fd) {
     if (er) return callback(er);
@@ -786,11 +787,7 @@ fs.ftruncate = function(fd, len = 0, callback) {
     len = 0;
   }
   validateUint32(fd, 'fd');
-  // TODO(BridgeAR): This does not seem right.
-  // There does not seem to be any validation before and if there is any, it
-  // should work similar to validateUint32 or not have a upper cap at all.
-  // This applies to all usage of `validateInt32(len, 'len')`.
-  validateInt32(len, 'len');
+  validateInteger(len, 'len');
   len = Math.max(0, len);
   const req = new FSReqWrap();
   req.oncomplete = makeCallback(callback);
@@ -799,7 +796,7 @@ fs.ftruncate = function(fd, len = 0, callback) {
 
 fs.ftruncateSync = function(fd, len = 0) {
   validateUint32(fd, 'fd');
-  validateInt32(len, 'len');
+  validateInteger(len, 'len');
   len = Math.max(0, len);
   const ctx = {};
   binding.ftruncate(fd, len, undefined, ctx);

lib/internal/fs/promises.js

@@ -34,7 +34,7 @@ const {
 } = require('internal/fs/utils');
 const {
   isUint32,
-  validateInt32,
+  validateInteger,
   validateUint32
 } = require('internal/validators');
 const pathModule = require('path');
@@ -265,7 +265,7 @@ async function truncate(path, len = 0) {
 
 async function ftruncate(handle, len = 0) {
   validateFileHandle(handle);
-  validateInt32(len, 'len');
+  validateInteger(len, 'len');
   len = Math.max(0, len);
   return binding.ftruncate(handle.fd, len, kUsePromises);
 }

lib/internal/validators.js

@@ -13,7 +13,21 @@ function isUint32(value) {
   return value === (value >>> 0);
 }
 
-function validateInt32(value, name) {
+function validateInteger(value, name) {
+  let err;
+
+  if (typeof value !== 'number')
+    err = new ERR_INVALID_ARG_TYPE(name, 'number', value);
+  else if (!Number.isSafeInteger(value))
+    err = new ERR_OUT_OF_RANGE(name, 'an integer', value);
+
+  if (err) {
+    Error.captureStackTrace(err, validateInteger);
+    throw err;
+  }
+}
+
+function validateInt32(value, name, min = -2147483648, max = 2147483647) {
   if (!isInt32(value)) {
     let err;
     if (typeof value !== 'number') {
@@ -53,6 +67,7 @@ function validateUint32(value, name, positive) {
 module.exports = {
   isInt32,
   isUint32,
+  validateInteger,
   validateInt32,
   validateUint32
 };

test/parallel/test-fs-truncate.js

@@ -179,6 +179,16 @@ function testFtruncate(cb) {
   process.on('exit', () => fs.closeSync(fd));
 
   ['', false, null, {}, []].forEach((input) => {
+    assert.throws(
+      () => fs.truncate(file5, input, common.mustNotCall()),
+      {
+        code: 'ERR_INVALID_ARG_TYPE',
+        name: 'TypeError [ERR_INVALID_ARG_TYPE]',
+        message: 'The "len" argument must be of type number. ' +
+                 `Received type ${typeof input}`
+      }
+    );
+
     assert.throws(
       () => fs.ftruncate(fd, input),
       {
@@ -191,6 +201,16 @@ function testFtruncate(cb) {
   });
 
   [-1.5, 1.5].forEach((input) => {
+    assert.throws(
+      () => fs.truncate(file5, input),
+      {
+        code: 'ERR_OUT_OF_RANGE',
+        name: 'RangeError [ERR_OUT_OF_RANGE]',
+        message: 'The value of "len" is out of range. It must be ' +
+                  `an integer. Received ${input}`
+      }
+    );
+
     assert.throws(
       () => fs.ftruncate(fd, input),
       {
@@ -200,17 +220,14 @@ function testFtruncate(cb) {
                   `an integer. Received ${input}`
       }
     );
-  });
 
-  // 2 ** 31 = 2147483648
-  [2147483648, -2147483649].forEach((input) => {
     assert.throws(
       () => fs.ftruncate(fd, input),
       {
         code: 'ERR_OUT_OF_RANGE',
         name: 'RangeError [ERR_OUT_OF_RANGE]',
         message: 'The value of "len" is out of range. It must be ' +
-                  `> -2147483649 && < 2147483648. Received ${input}`
+                  `an integer. Received ${input}`
       }
     );
   });