From 33d8a82aacbb709d13761caa3089c673b9558dd9 Mon Sep 17 00:00:00 2001
From: Francis Dupont <fdupont@isc.org>
Date: Sun, 3 Aug 2025 18:59:40 +0200
Subject: [PATCH] [#4037] Replaced umask by fchmod

---
 src/lib/log/interprocess/interprocess_sync_file.cc | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/src/lib/log/interprocess/interprocess_sync_file.cc b/src/lib/log/interprocess/interprocess_sync_file.cc
index ed6a5b7e2f..c77b9ea3f9 100644
--- a/src/lib/log/interprocess/interprocess_sync_file.cc
+++ b/src/lib/log/interprocess/interprocess_sync_file.cc
@@ -54,10 +54,14 @@ InterprocessSyncFile::do_lock(int cmd, short l_type) {
 
         // Open the lockfile in the constructor so it doesn't do the access
         // checks every time a message is logged.
-        const mode_t mode = umask(S_IXUSR | S_IXGRP | S_IXOTH); // 0111
         fd_ = open(lockfile_path.c_str(), O_CREAT | O_RDWR,
                    S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP); // 0660
-        umask(mode);
+        if (fd_ != -1) {
+            if (fchmod(fd_, S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP) != 0) {
+                close(fd_);
+                fd_ = -1;
+            }
+        }
 
         if (fd_ == -1) {
             std::stringstream tmp;