Always reject files external to app

Previously, when using `render file:`, it was possible to render files
not only at an absolute path or relative to the current directory, but
relative to ANY view paths. This was probably done for absolutely
maximum compatibility when addressing CVE-2016-0752, but I think is
unlikely to be used in practice.

Tihs commit removes the ability to `render file:` with a path relative
to a non-fallback view path.

Make FallbackResolver.new private

To ensure nobody is making FallbackResolvers other than "/" and "".

Make reject_files_external_... no-op for fallbacks

Because there are only two values used for path: "" and "/", and
File.join("", "") == File.join("/", "") == "/", this method was only
testing that the absolute paths started at "/" (which of course all do).

This commit doesn't change any behaviour, but it makes it explicit that
the FallbackFileSystemResolver works this way.

Remove outside_app_allowed argument

Deprecate find_all_anywhere

This is now equivalent to find_all

Remove outside_app argument

Deprecate find_file for find

Both LookupContext#find_file and PathSet#find_file are now equivalent to
their respective #find methods.

2 files changed, 5 insertions, 5 deletions

diff --git a/actionview/test/template/fallback_file_system_resolver_test.rb b/actionview/test/template/fallback_file_system_resolver_test.rb
index 304cdb8a03..fa770f3a15 100644
--- a/actionview/test/template/fallback_file_system_resolver_test.rb
+++ b/actionview/test/template/fallback_file_system_resolver_test.rb
@@ -4,7 +4,7 @@ require "abstract_unit"
 
 class FallbackFileSystemResolverTest < ActiveSupport::TestCase
   def setup
-    @root_resolver = ActionView::FallbackFileSystemResolver.new("/")
+    @root_resolver = ActionView::FallbackFileSystemResolver.send(:new, "/")
   end
 
   def test_should_have_no_virtual_path
diff --git a/actionview/test/template/lookup_context_test.rb b/actionview/test/template/lookup_context_test.rb
index 3e357fe1a7..72e1f50fdf 100644
--- a/actionview/test/template/lookup_context_test.rb
+++ b/actionview/test/template/lookup_context_test.rb
@@ -143,16 +143,16 @@ class LookupContextTest < ActiveSupport::TestCase
     assert_deprecated do
       @lookup_context.with_fallbacks do
         assert_equal 3, @lookup_context.view_paths.size
-        assert_includes @lookup_context.view_paths, ActionView::FallbackFileSystemResolver.new("")
-        assert_includes @lookup_context.view_paths, ActionView::FallbackFileSystemResolver.new("/")
+        assert_includes @lookup_context.view_paths, ActionView::FallbackFileSystemResolver.instances[0]
+        assert_includes @lookup_context.view_paths, ActionView::FallbackFileSystemResolver.instances[1]
       end
     end
 
     @lookup_context = @lookup_context.with_fallbacks
 
     assert_equal 3, @lookup_context.view_paths.size
-    assert_includes @lookup_context.view_paths, ActionView::FallbackFileSystemResolver.new("")
-    assert_includes @lookup_context.view_paths, ActionView::FallbackFileSystemResolver.new("/")
+    assert_includes @lookup_context.view_paths, ActionView::FallbackFileSystemResolver.instances[0]
+    assert_includes @lookup_context.view_paths, ActionView::FallbackFileSystemResolver.instances[1]
   end
 
   test "add fallbacks just once in nested fallbacks calls" do