From ed7d14967599a9dbace7cabbe287d7c9d5b767a0 Mon Sep 17 00:00:00 2001
From: RafaelGSS <rafael.nunu@hotmail.com>
Date: Mon, 8 Jan 2024 16:03:43 -0300
Subject: [PATCH] lib: use cache fs internals against path traversal

PR-URL: https://github.com/nodejs-private/node-private/pull/516
Fixes: https://hackerone.com/bugs?subject=nodejs&report_id=2259914
Reviewed-By: Moshe Atlow <moshe@atlow.co.il>
CVE-ID: CVE-2024-21891
---
 lib/internal/process/pre_execution.js    |  3 +++
 test/fixtures/permission/fs-traversal.js | 27 ++++++++++++++++++++++--
 2 files changed, 28 insertions(+), 2 deletions(-)

diff --git a/lib/internal/process/pre_execution.js b/lib/internal/process/pre_execution.js
index 9142fed75e9050..cffffc28d3d703 100644
--- a/lib/internal/process/pre_execution.js
+++ b/lib/internal/process/pre_execution.js
@@ -12,6 +12,7 @@ const {
   NumberParseInt,
   ObjectDefineProperties,
   ObjectDefineProperty,
+  ObjectFreeze,
   ObjectGetOwnPropertyDescriptor,
   SafeMap,
   String,
@@ -597,6 +598,8 @@ function initializePermission() {
     process.binding = function binding(_module) {
       throw new ERR_ACCESS_DENIED('process.binding');
     };
+    // Guarantee path module isn't monkey-patched to bypass permission model
+    ObjectFreeze(require('path'));
     process.emitWarning('Permission is an experimental feature',
                         'ExperimentalWarning');
     const { has, deny } = require('internal/process/permission');
diff --git a/test/fixtures/permission/fs-traversal.js b/test/fixtures/permission/fs-traversal.js
index f0a14805aa9c71..5a127f75474da8 100644
--- a/test/fixtures/permission/fs-traversal.js
+++ b/test/fixtures/permission/fs-traversal.js
@@ -6,9 +6,12 @@ const assert = require('assert');
 const fs = require('fs');
 const path = require('path');
 
-// This should not affect how the permission model resolves paths.
 const { resolve } = path;
-path.resolve = (s) => s;
+// This should not affect how the permission model resolves paths.
+try {
+  path.resolve = (s) => s;
+  assert.fail('should not be called');
+} catch {}
 
 const blockedFolder = process.env.BLOCKEDFOLDER;
 const allowedFolder = process.env.ALLOWEDFOLDER;
@@ -96,6 +99,26 @@ const uint8ArrayTraversalPath = new TextEncoder().encode(traversalPath);
   }));
 }
 
+// Monkey-patching path module should also not allow path traversal.
+{
+  const fs = require('fs');
+  const path = require('path');
+
+  const cwd = Buffer.from('.');
+  try {
+    path.toNamespacedPath = (path) => { return traversalPath; };
+    assert.fail('should throw error when pacthing');
+  } catch { }
+
+  assert.throws(() => {
+    fs.readFile(cwd, common.mustNotCall());
+  }, common.expectsError({
+    code: 'ERR_ACCESS_DENIED',
+    permission: 'FileSystemRead',
+    resource: resolve(cwd.toString()),
+  }));
+}
+
 // Monkey-patching Buffer internals should also not allow path traversal.
 {
   const extraChars = '.'.repeat(40);