add unknown xml elements to the xml again

lib/diaspora_federation/entities/relayable.rb

@@ -77,6 +77,8 @@ module DiasporaFederation
           hash = to_signed_h
           xml.at_xpath("author_signature").content = hash[:author_signature]
           xml.at_xpath("parent_author_signature").content = hash[:parent_author_signature]
+
+          add_additional_elements_to(xml) if additional_xml_elements
         end
       end
 
@@ -105,6 +107,14 @@ module DiasporaFederation
         end
       end
 
+      # Adds additional unknown elements to the xml
+      # @param [Nokogiri::XML::Element] xml entity xml
+      def add_additional_elements_to(xml)
+        additional_xml_elements.each do |element, value|
+          xml << Nokogiri::XML::Element.new(element, xml.document).tap {|node| node.content = value }
+        end
+      end
+
       # this happens only on downstream federation
       def verify_parent_author_signature
         pubkey = DiasporaFederation.callbacks.trigger(:fetch_author_public_key_by_entity_guid, parent_type, parent_guid)

spec/lib/diaspora_federation/entities/relayable_spec.rb

@@ -6,26 +6,30 @@ module DiasporaFederation
     let(:guid) { FactoryGirl.generate(:guid) }
     let(:parent_guid) { FactoryGirl.generate(:guid) }
     let(:diaspora_id) { FactoryGirl.generate(:diaspora_id) }
+    let(:property) { "hello" }
     let(:new_property) { "some text" }
-    let(:hash) { {guid: guid, diaspora_id: diaspora_id, parent_guid: parent_guid} }
+    let(:hash) { {guid: guid, diaspora_id: diaspora_id, parent_guid: parent_guid, property: property} }
 
-    let(:signature_data) { "#{diaspora_id};#{guid};#{parent_guid}" }
+    let(:signature_data) { "#{diaspora_id};#{guid};#{parent_guid};#{property}" }
-    let(:signature_data_with_new_property) { "#{diaspora_id};#{guid};#{new_property};#{parent_guid}" }
+    let(:signature_data_with_new_property) { "#{diaspora_id};#{guid};#{new_property};#{parent_guid};#{property}" }
-    let(:legacy_signature_data) { "#{guid};#{diaspora_id};#{parent_guid}" }
+    let(:legacy_signature_data) { "#{guid};#{diaspora_id};#{property};#{parent_guid}" }
 
     class SomeRelayable < Entity
-      LEGACY_SIGNATURE_ORDER = %i(guid diaspora_id parent_guid).freeze
+      LEGACY_SIGNATURE_ORDER = %i(guid diaspora_id property parent_guid).freeze
-
-      property :guid
-      property :diaspora_id, xml_name: :diaspora_handle
 
       include Entities::Relayable
 
+      property :property
+
       def parent_type
         "Parent"
       end
     end
 
+    def verify_signature(pubkey, signature, signed_string)
+      pubkey.verify(OpenSSL::Digest::SHA256.new, Base64.decode64(signature), signed_string)
+    end
+
     describe "#verify_signatures" do
       def sign_with_key(privkey, signature_data)
         Base64.strict_encode64(privkey.sign(OpenSSL::Digest::SHA256.new, signature_data))
@@ -186,10 +190,6 @@ module DiasporaFederation
     end
 
     describe "#to_signed_h" do
-      def verify_signature(pubkey, signature, signed_string)
-        pubkey.verify(OpenSSL::Digest::SHA256.new, Base64.decode64(signature), signed_string)
-      end
-
       it "updates signatures when they were nil and keys were supplied" do
         expect(DiasporaFederation.callbacks).to receive(:trigger).with(
           :fetch_private_key_by_diaspora_id, diaspora_id
@@ -251,5 +251,44 @@ module DiasporaFederation
         end
       end
     end
+
+    describe "#to_xml" do
+      it "adds new unknown xml elements to the xml again" do
+        hash.merge!(author_signature: "aa", parent_author_signature: "bb")
+        xml = SomeRelayable.new(hash, "new_property" => new_property).to_xml
+
+        expected_xml = <<-XML
+<some_relayable>
+  <diaspora_handle>#{diaspora_id}</diaspora_handle>
+  <guid>#{guid}</guid>
+  <parent_guid>#{parent_guid}</parent_guid>
+  <author_signature>aa</author_signature>
+  <parent_author_signature>bb</parent_author_signature>
+  <property>#{property}</property>
+  <new_property>#{new_property}</new_property>
+</some_relayable>
+XML
+
+        expect(xml.to_s.strip).to eq(expected_xml.strip)
+      end
+
+      it "computes correct signatures for the entity" do
+        expect(DiasporaFederation.callbacks).to receive(:trigger).with(
+          :fetch_private_key_by_diaspora_id, diaspora_id
+        ).and_return(author_pkey)
+
+        expect(DiasporaFederation.callbacks).to receive(:trigger).with(
+          :fetch_author_private_key_by_entity_guid, "Parent", parent_guid
+        ).and_return(parent_pkey)
+
+        xml = DiasporaFederation::Salmon::XmlPayload.pack(SomeRelayable.new(hash))
+
+        author_signature = xml.at_xpath("post/*[1]/author_signature").text
+        parent_author_signature = xml.at_xpath("post/*[1]/parent_author_signature").text
+
+        expect(verify_signature(author_pkey, author_signature, legacy_signature_data)).to be_truthy
+        expect(verify_signature(parent_pkey, parent_author_signature, legacy_signature_data)).to be_truthy
+      end
+    end
   end
 end

spec/support/shared_entity_specs.rb

@@ -75,7 +75,7 @@ shared_examples "a relayable Entity" do
   let(:instance) { described_class.new(data.merge(author_signature: nil, parent_author_signature: nil)) }
 
   context "signatures generation" do
-    def legacy_verify_signature(pubkey, signature, signed_string)
+    def verify_signature(pubkey, signature, signed_string)
       pubkey.verify(OpenSSL::Digest::SHA256.new, Base64.decode64(signature), signed_string)
     end
 
@@ -89,8 +89,8 @@ shared_examples "a relayable Entity" do
 
       alice_public_key = OpenSSL::PKey::RSA.new(alice.serialized_public_key)
       bob_public_key = OpenSSL::PKey::RSA.new(bob.serialized_public_key)
-      expect(legacy_verify_signature(alice_public_key, author_signature, signed_string)).to be_truthy
+      expect(verify_signature(alice_public_key, author_signature, signed_string)).to be_truthy
-      expect(legacy_verify_signature(bob_public_key, parent_author_signature, signed_string)).to be_truthy
+      expect(verify_signature(bob_public_key, parent_author_signature, signed_string)).to be_truthy
     end
   end
 end