Reuse `InternalRedirect` for the `EE::SessionsController`

app/controllers/concerns/internal_redirect.rb

 module InternalRedirect
+  prepend EE::InternalRedirect
   extend ActiveSupport::Concern
 
   def safe_redirect_path(path)

ee/app/controllers/concerns/ee/internal_redirect.rb

+module EE
+  module InternalRedirect
+    extend ::Gitlab::Utils::Override
+
+    override :host_allowed?
+    def host_allowed?(uri)
+      return true if super
+
+      # Redirect is not only allowed to current host, but also to other Geo
+      # nodes. relative_url_root *must* be ignored here as we don't know what
+      # is root and what is path
+      truncated = uri.dup.tap { |uri| uri.path = '/' }
+      ::GeoNode.with_url_prefix(truncated).exists?
+    end
+  end
+end

ee/app/controllers/ee/sessions_controller.rb

@@ -36,17 +36,5 @@ module EE
 
       super
     end
-
-    override :redirect_allowed_to?
-    def redirect_allowed_to?(uri)
-      # Redirect is not only allowed to current host, but also to other Geo
-      # nodes. relative_url_root *must* be ignored here as we don't know what
-      # is root and what is path
-      super || begin
-        truncated = uri.dup.tap { |uri| uri.path = '/' }
-
-        ::GeoNode.with_url_prefix(truncated).exists?
-      end
-    end
   end
 end

ee/spec/controllers/concerns/internal_redirect_spec.rb

+require 'spec_helper'
+
+describe InternalRedirect do
+  let(:controller_class) do
+    Class.new do
+      include InternalRedirect
+
+      def request
+        @request ||= Struct.new(:host, :port).new('test.host', 80)
+      end
+    end
+  end
+  subject(:controller) { controller_class.new }
+
+  describe '#host_allowed?' do
+    it 'allows redirecting to existing geo nodes' do
+      create(:geo_node, url: 'http://narnia.test.host')
+
+      expect(controller.host_allowed?(URI('http://narnia.test.host/test'))).to be(true)
+    end
+  end
+end