allow :file to be outside rails root, but anything else must be inside the rails view directory

CVE-2016-0752

2 files changed, 38 insertions, 1 deletions

diff --git a/actionpack/lib/abstract_controller/rendering.rb b/actionpack/lib/abstract_controller/rendering.rb
index a73f188623..63fd76d9b7 100644
--- a/actionpack/lib/abstract_controller/rendering.rb
+++ b/actionpack/lib/abstract_controller/rendering.rb
@@ -82,7 +82,13 @@ module AbstractController
     # <tt>render :file => "foo/bar"</tt>.
     # :api: plugin
     def _normalize_args(action=nil, options={})
-      if action.is_a? Hash
+      case action
+      when ActionController::Parameters
+        unless action.permitted?
+          raise ArgumentError, "render parameters are not permitted"
+        end
+        action
+      when Hash
         action
       else
         options
diff --git a/actionpack/test/controller/render_test.rb b/actionpack/test/controller/render_test.rb
index 256ebf6a07..bbc216b52f 100644
--- a/actionpack/test/controller/render_test.rb
+++ b/actionpack/test/controller/render_test.rb
@@ -62,6 +62,16 @@ class TestController < ActionController::Base
     end
   end
 
+  def dynamic_render
+    render params[:id] # => String, AC:Params
+  end
+
+  def dynamic_render_with_file
+    # This is extremely bad, but should be possible to do.
+    file = params[:id] # => String, AC:Params
+    render file: file
+  end
+
   class Collection
     def initialize(records)
       @records = records
@@ -243,6 +253,27 @@ end
 class ExpiresInRenderTest < ActionController::TestCase
   tests TestController
 
+  def test_dynamic_render_with_file
+    # This is extremely bad, but should be possible to do.
+    assert File.exist?(File.join(File.dirname(__FILE__), '../../test/abstract_unit.rb'))
+    response = get :dynamic_render_with_file, params: { id: '../\\../test/abstract_unit.rb' }
+    assert_equal File.read(File.join(File.dirname(__FILE__), '../../test/abstract_unit.rb')),
+      response.body
+  end
+
+  def test_dynamic_render
+    assert File.exist?(File.join(File.dirname(__FILE__), '../../test/abstract_unit.rb'))
+    assert_raises ActionView::MissingTemplate do
+      get :dynamic_render, params: { id: '../\\../test/abstract_unit.rb' }
+    end
+  end
+
+  def test_dynamic_render_file_hash
+    assert_raises ArgumentError do
+      get :dynamic_render, params: { id: { file: '../\\../test/abstract_unit.rb' } }
+    end
+  end
+
   def test_expires_in_header
     get :conditional_hello_with_expires_in
     assert_equal "max-age=60, private", @response.headers["Cache-Control"]