From e7b1af9644098ede2595ca7ca68455552055a44d Mon Sep 17 00:00:00 2001
From: fru1tworld <fruitworld.planet@gmail.com>
Date: Tue, 28 Apr 2026 13:29:42 +0900
Subject: [PATCH] fs: open symlinks O_RDONLY in lchmod

fchmod does not require write access, so O_WRONLY is unnecessary.

Refs: https://github.com/nodejs/node/issues/23736
---
 lib/fs.js                   | 6 +++---
 lib/internal/fs/promises.js | 4 ++--
 2 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/lib/fs.js b/lib/fs.js
index d63fad8b2a258b..f44d0e8a793eb4 100644
--- a/lib/fs.js
+++ b/lib/fs.js
@@ -55,7 +55,7 @@ const {
   S_IFREG,
   S_IFSOCK,
   F_OK,
-  O_WRONLY,
+  O_RDONLY,
   O_SYMLINK,
 } = constants;
 
@@ -1971,7 +1971,7 @@ function fchmodSync(fd, mode) {
 function lchmod(path, mode, callback) {
   validateFunction(callback, 'cb');
   mode = parseFileMode(mode, 'mode');
-  fs.open(path, O_WRONLY | O_SYMLINK, (err, fd) => {
+  fs.open(path, O_RDONLY | O_SYMLINK, (err, fd) => {
     if (err) {
       callback(err);
       return;
@@ -1993,7 +1993,7 @@ function lchmod(path, mode, callback) {
  * @returns {void}
  */
 function lchmodSync(path, mode) {
-  const fd = fs.openSync(path, O_WRONLY | O_SYMLINK);
+  const fd = fs.openSync(path, O_RDONLY | O_SYMLINK);
 
   // Prefer to return the chmod error, if one occurs,
   // but still try to close, and report closing errors if they occur.
diff --git a/lib/internal/fs/promises.js b/lib/internal/fs/promises.js
index 40de890c6eb2d3..91e01607ed1ee9 100644
--- a/lib/internal/fs/promises.js
+++ b/lib/internal/fs/promises.js
@@ -26,8 +26,8 @@ const {
 const { fs: constants } = internalBinding('constants');
 const {
   F_OK,
+  O_RDONLY,
   O_SYMLINK,
-  O_WRONLY,
   S_IFMT,
   S_IFREG,
 } = constants;
@@ -1742,7 +1742,7 @@ async function lchmod(path, mode) {
   if (O_SYMLINK === undefined)
     throw new ERR_METHOD_NOT_IMPLEMENTED('lchmod()');
 
-  const fd = await open(path, O_WRONLY | O_SYMLINK);
+  const fd = await open(path, O_RDONLY | O_SYMLINK);
   return handleFdClose(fchmod(fd, mode), fd.close);
 }