diff --git a/runtime/os_linux.cc b/runtime/os_linux.cc
index 0add496..ae86a2f 100644
--- a/runtime/os_linux.cc
+++ b/runtime/os_linux.cc
@@ -55,7 +55,8 @@
   CHECK(name != nullptr);
   bool read_only = ((flags & O_ACCMODE) == O_RDONLY);
   bool check_usage = !read_only && auto_flush;
-  std::unique_ptr<File> file(new File(name, flags, 0666, check_usage));
+  std::unique_ptr<File> file(
+      new File(name, flags, S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH, check_usage));
   if (!file->IsOpened()) {
     return nullptr;
   }