fs: validate encoding to binding.writeString()

The binding layer performs some validation of the encoding and
data passed to WriteString(). This commit adds similar validation
to the JS layer for better error handling.

PR-URL: #38183
Fixes: #38168
Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de>
Reviewed-By: Antoine du Hamel <duhamelantoine1995@gmail.com>
Reviewed-By: Darshan Sen <raisinten@gmail.com>
Reviewed-By: Anto Aravinth <anto.aravinth.cse@gmail.com>

lib/fs.js

@@ -133,6 +133,7 @@ const {
   validateBoolean,
   validateBuffer,
   validateCallback,
+  validateEncoding,
   validateFunction,
   validateInteger,
 } = require('internal/validators');
@@ -702,11 +703,14 @@ function write(fd, buffer, offset, length, position, callback) {
     }
     length = 'utf8';
   }
+
+  const str = String(buffer);
+  validateEncoding(str, length);
   callback = maybeCallback(position);
 
   const req = new FSReqCallback();
   req.oncomplete = wrapper;
-  return binding.writeString(fd, String(buffer), offset, length, req);
+  return binding.writeString(fd, str, offset, length, req);
 }
 
 ObjectDefineProperty(write, internalUtil.customPromisifyArgs,
@@ -735,6 +739,7 @@ function writeSync(fd, buffer, offset, length, position) {
                                  undefined, ctx);
   } else {
     validateStringAfterArrayBufferView(buffer, 'buffer');
+    validateEncoding(buffer, length);
 
     if (offset === undefined)
       offset = null;

lib/internal/fs/promises.js

@@ -70,6 +70,7 @@ const {
   validateAbortSignal,
   validateBoolean,
   validateBuffer,
+  validateEncoding,
   validateInteger,
 } = require('internal/validators');
 const pathModule = require('path');
@@ -467,6 +468,7 @@ async function write(handle, buffer, offset, length, position) {
   }
 
   validateStringAfterArrayBufferView(buffer, 'buffer');
+  validateEncoding(buffer, length);
   const bytesWritten = (await binding.writeString(handle.fd, buffer, offset,
                                                   length, kUsePromises)) || 0;
   return { bytesWritten, buffer };

test/parallel/test-fs-promises.js

@@ -436,6 +436,22 @@ async function getHandle(dest) {
       );
     }
 
+    // Regression test for https://github.com/nodejs/node/issues/38168
+    {
+      const handle = await getHandle(dest);
+
+      assert.rejects(
+        async () => handle.write('abc', 0, 'hex'),
+        {
+          code: 'ERR_INVALID_ARG_VALUE',
+          message: /'encoding' is invalid for data of length 3/
+        }
+      );
+
+      const ret = await handle.write('abcd', 0, 'hex');
+      assert.strictEqual(ret.bytesWritten, 2);
+      await handle.close();
+    }
   }
 
   doTest().then(common.mustCall());

test/parallel/test-fs-write.js

@@ -33,6 +33,7 @@ const fn = path.join(tmpdir.path, 'write.txt');
 const fn2 = path.join(tmpdir.path, 'write2.txt');
 const fn3 = path.join(tmpdir.path, 'write3.txt');
 const fn4 = path.join(tmpdir.path, 'write4.txt');
+const fn5 = path.join(tmpdir.path, 'write5.txt');
 const expected = 'ümlaut.';
 const constants = fs.constants;
 
@@ -170,3 +171,31 @@ fs.open(fn4, 'w', 0o644, common.mustSucceed((fd) => {
     }
   );
 });
+
+{
+  // Regression test for https://github.com/nodejs/node/issues/38168
+  const fd = fs.openSync(fn5, 'w');
+
+  assert.throws(
+    () => fs.writeSync(fd, 'abc', 0, 'hex'),
+    {
+      code: 'ERR_INVALID_ARG_VALUE',
+      message: /'encoding' is invalid for data of length 3/
+    }
+  );
+
+  assert.throws(
+    () => fs.writeSync(fd, 'abc', 0, 'hex', common.mustNotCall()),
+    {
+      code: 'ERR_INVALID_ARG_VALUE',
+      message: /'encoding' is invalid for data of length 3/
+    }
+  );
+
+  assert.strictEqual(fs.writeSync(fd, 'abcd', 0, 'hex'), 2);
+
+  fs.write(fd, 'abcd', 0, 'hex', common.mustSucceed((written) => {
+    assert.strictEqual(written, 2);
+    fs.closeSync(fd);
+  }));
+}