lib: mask mode_t type of arguments with 0o777

- Introduce the `validateAndMaskMode` validator that
  validates `mode_t` arguments and mask them with 0o777
  if they are 32-bit unsigned integer or octal string
  to be more consistent with POSIX APIs.
- Use the validator in fs APIs and process.umask for
  consistency.
- Add tests for 32-bit unsigned modes larger than 0o777.

PR-URL: https://github.com/nodejs/node/pull/20636
Fixes: https://github.com/nodejs/node/issues/20498
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Anatoli Papirovski <apapirovski@mac.com>

1 files changed, 48 insertions, 0 deletions

diff --git a/test/parallel/test-fs-open-mode-mask.js b/test/parallel/test-fs-open-mode-mask.js
new file mode 100644
index 0000000000..4db41864af
--- /dev/null
+++ b/test/parallel/test-fs-open-mode-mask.js
@@ -0,0 +1,48 @@
+'use strict';
+
+// This tests that mode > 0o777 will be masked off with 0o777 in fs.open().
+
+const common = require('../common');
+const assert = require('assert');
+const path = require('path');
+const fs = require('fs');
+
+let mode;
+
+if (common.isWindows) {
+  mode = 0o444;
+} else {
+  mode = 0o644;
+}
+
+const maskToIgnore = 0o10000;
+
+const tmpdir = require('../common/tmpdir');
+tmpdir.refresh();
+
+function test(mode, asString) {
+  const suffix = asString ? 'str' : 'num';
+  const input = asString ?
+    (mode | maskToIgnore).toString(8) : (mode | maskToIgnore);
+
+  {
+    const file = path.join(tmpdir.path, `openSync-${suffix}.txt`);
+    const fd = fs.openSync(file, 'w+', input);
+    assert.strictEqual(fs.fstatSync(fd).mode & 0o777, mode);
+    fs.closeSync(fd);
+    assert.strictEqual(fs.statSync(file).mode & 0o777, mode);
+  }
+
+  {
+    const file = path.join(tmpdir.path, `open-${suffix}.txt`);
+    fs.open(file, 'w+', input, common.mustCall((err, fd) => {
+      assert.ifError(err);
+      assert.strictEqual(fs.fstatSync(fd).mode & 0o777, mode);
+      fs.closeSync(fd);
+      assert.strictEqual(fs.statSync(file).mode & 0o777, mode);
+    }));
+  }
+}
+
+test(mode, true);
+test(mode, false);