mktemp: Prevent race condition when setting permissions for tempdir

src/uu/mktemp/src/mktemp.rs

@@ -458,12 +458,18 @@ fn dry_exec(tmpdir: &Path, prefix: &str, rand: usize, suffix: &str) -> UResult<P
 fn make_temp_dir(dir: &Path, prefix: &str, rand: usize, suffix: &str) -> UResult<PathBuf> {
     let mut builder = Builder::new();
     builder.prefix(prefix).rand_bytes(rand).suffix(suffix);
+
+    // On *nix platforms grant read-write-execute for owner only.
+    // The directory is created with these permission at creation time, using mkdir(3) syscall.
+    // This is not relevant on Windows systems. See: https://docs.rs/tempfile/latest/tempfile/#security
+    // `fs` is not imported on Windows anyways.
+    #[cfg(not(windows))]
+    builder.permissions(fs::Permissions::from_mode(0o700));
+
     match builder.tempdir_in(dir) {
         Ok(d) => {
             // `into_path` consumes the TempDir without removing it
             let path = d.into_path();
-            #[cfg(not(windows))]
-            fs::set_permissions(&path, fs::Permissions::from_mode(0o700))?;
             Ok(path)
         }
         Err(e) if e.kind() == ErrorKind::NotFound => {