lib: add empty buffer case to read and readSync function in fs

While using read() or readSync() function, it should be verified that
the arguments of the function are in proper range and hold legitimate
values, for a successful read process.
For this validateOffsetLengthRead() function is called, which gives an
error message for offset and length passed by the user, if not in
order. But there should also be an error when an empty buffer is passed
as argument, when it cannot be written over.
The empty buffer case should be checked before calling
validateOffsetLengthRead() and ERR_INVALID_ARG_VALUE should be thrown
corresponding to the empty buffer argument in read and readSync
function.

Fixes: nodejs#21193

Author: AdityaSrivast

lib/fs.js

@@ -47,6 +47,7 @@ const { Buffer, kMaxLength } = require('buffer');
 const errors = require('internal/errors');
 const {
   ERR_FS_FILE_TOO_LARGE,
+  ERR_INVALID_ARG_VALUE,
   ERR_INVALID_ARG_TYPE,
   ERR_INVALID_CALLBACK
 } = errors.codes;
@@ -457,6 +458,11 @@ function read(fd, buffer, offset, length, position, callback) {
     });
   }
 
+  if (buffer.length === 0) {
+    throw new ERR_INVALID_ARG_VALUE('buffer', buffer,
+                                    'is empty and cannot be written');
+  }
+
   validateOffsetLengthRead(offset, length, buffer.length);
 
   if (!Number.isSafeInteger(position))
@@ -487,6 +493,11 @@ function readSync(fd, buffer, offset, length, position) {
     return 0;
   }
 
+  if (buffer.length === 0) {
+    throw new ERR_INVALID_ARG_VALUE('buffer', buffer,
+                                    'is empty and cannot be written');
+  }
+
   validateOffsetLengthRead(offset, length, buffer.length);
 
   if (!Number.isSafeInteger(position))

lib/internal/fs/promises.js

@@ -12,6 +12,7 @@ const { Buffer, kMaxLength } = require('buffer');
 const {
   ERR_FS_FILE_TOO_LARGE,
   ERR_INVALID_ARG_TYPE,
+  ERR_INVALID_ARG_VALUE,
   ERR_METHOD_NOT_IMPLEMENTED
 } = require('internal/errors').codes;
 const { getPathFromURL } = require('internal/url');
@@ -207,6 +208,11 @@ async function read(handle, buffer, offset, length, position) {
   if (length === 0)
     return { bytesRead: length, buffer };
 
+  if (buffer.length === 0) {
+    throw new ERR_INVALID_ARG_VALUE('buffer', buffer,
+                                    'is empty and cannot be written');
+  }
+
   validateOffsetLengthRead(offset, length, buffer.length);
 
   if (!Number.isSafeInteger(position))

lib/internal/fs/utils.js

@@ -293,12 +293,8 @@ function validateOffsetLengthRead(offset, length, bufferLength) {
   let err;
 
   if (offset < 0 || offset >= bufferLength) {
-    if (bufferLength === 0) {
-      err = new ERR_OUT_OF_RANGE('bufferLength', '> 0', bufferLength);
-    } else {
-      err = new ERR_OUT_OF_RANGE('offset',
-                                 `>= 0 && <= ${bufferLength}`, offset);
-    }
+    err = new ERR_OUT_OF_RANGE('offset',
+                               `>= 0 && <= ${bufferLength}`, offset);
   } else if (length < 0 || offset + length > bufferLength) {
     err = new ERR_OUT_OF_RANGE('length',
                                `>= 0 && <= ${bufferLength - offset}`, length);

test/parallel/test-fs-read-empty-buffer.js

@@ -11,8 +11,6 @@ const buffer = new Uint8Array();
 assert.throws(
   () => fs.readSync(fd, buffer, 0, 10, 0),
   {
-    code: 'ERR_OUT_OF_RANGE',
-    message: 'The value of "bufferLength" is out of range. ' +
-            'It must be > 0. Received 0'
+    code: 'ERR_INVALID_ARG_VALUE',
   }
 );