From 91376a3e26551fa0ad619f633a17038a846dedf4 Mon Sep 17 00:00:00 2001
From: cmrd Senya <senya@riseup.net>
Date: Wed, 2 Dec 2015 04:33:49 +0300
Subject: [PATCH] Retractions signatures support

---
 lib/diaspora_federation.rb                    | 11 +--
 lib/diaspora_federation/entities/relayable.rb | 16 +++--
 .../entities/relayable_retraction.rb          | 42 +++++++++++-
 .../entities/signed_retraction.rb             | 34 +++++++++-
 lib/diaspora_federation/test.rb               | 24 +++++++
 lib/diaspora_federation/test/factories.rb     | 10 +--
 .../relayable_retraction_validator.rb         |  4 --
 .../validators/signed_retraction_validator.rb |  2 -
 .../entities/relayable_retraction_spec.rb     | 67 ++++++++++++++++++-
 .../entities/relayable_spec.rb                | 65 +++++++++++++-----
 .../entities/signed_retraction_spec.rb        | 38 ++++++++++-
 .../relayable_retraction_validator_spec.rb    |  8 +--
 .../signed_retraction_validator_spec.rb       |  8 +--
 spec/spec_helper.rb                           |  2 +-
 .../initializers/diaspora_federation.rb       | 14 ++--
 15 files changed, 281 insertions(+), 64 deletions(-)

diff --git a/lib/diaspora_federation.rb b/lib/diaspora_federation.rb
index 08598c5..420bc4d 100644
--- a/lib/diaspora_federation.rb
+++ b/lib/diaspora_federation.rb
@@ -21,11 +21,12 @@ module DiasporaFederation
     fetch_person_for_webfinger
     fetch_person_for_hcard
     save_person_after_webfinger
-    fetch_private_key_by_id
-    fetch_private_key_by_post_guid
-    fetch_public_key_by_id
-    fetch_public_key_by_post_guid
-    post_author_is_local?
+    fetch_private_key_by_diaspora_id
+    fetch_author_private_key_by_entity_guid
+    fetch_public_key_by_diaspora_id
+    fetch_author_public_key_by_entity_guid
+    entity_author_is_local?
+    fetch_entity_author_id_by_guid
   )
 
   class << self
diff --git a/lib/diaspora_federation/entities/relayable.rb b/lib/diaspora_federation/entities/relayable.rb
index 09f9960..26c76be 100644
--- a/lib/diaspora_federation/entities/relayable.rb
+++ b/lib/diaspora_federation/entities/relayable.rb
@@ -52,22 +52,22 @@ module DiasporaFederation
       # @param [Hash] data hash with data to verify
       # @raise [SignatureVerificationFailed] if the signature is not valid or no public key is found
       def self.verify_signatures(data)
-        pkey = DiasporaFederation.callbacks.trigger(:fetch_public_key_by_id, data[:diaspora_id])
+        pkey = DiasporaFederation.callbacks.trigger(:fetch_public_key_by_diaspora_id, data[:diaspora_id])
         raise SignatureVerificationFailed, "failed to fetch public key for #{data[:diaspora_id]}" if pkey.nil?
         raise SignatureVerificationFailed, "wrong author_signature" unless Signing.verify_signature(
           data, data[:author_signature], pkey
         )
 
-        author_is_local = DiasporaFederation.callbacks.trigger(:post_author_is_local?, data[:parent_guid])
+        author_is_local = DiasporaFederation.callbacks.trigger(:entity_author_is_local?, "Post", data[:parent_guid])
         verify_parent_signature(data) unless author_is_local
       end
 
       # this happens only on downstream federation
       # @param [Hash] data hash with data to verify
       def self.verify_parent_signature(data)
-        pkey = DiasporaFederation.callbacks.trigger(:fetch_public_key_by_post_guid, data[:parent_guid])
+        pkey = DiasporaFederation.callbacks.trigger(:fetch_author_public_key_by_entity_guid, "Post", data[:parent_guid])
         raise SignatureVerificationFailed,
-              "failed to fetch public key for parent of #{data[:parent_guid]}" if pkey.nil?
+              "failed to fetch public key for author of #{data[:parent_guid]}" if pkey.nil?
         raise SignatureVerificationFailed, "wrong parent_author_signature" unless Signing.verify_signature(
           data, data[:parent_author_signature], pkey
         )
@@ -80,12 +80,16 @@ module DiasporaFederation
       # @param [Hash] data hash given for a signing
       def self.update_signatures!(data)
         if data[:author_signature].nil?
-          pkey = DiasporaFederation.callbacks.trigger(:fetch_private_key_by_id, data[:diaspora_id])
+          pkey = DiasporaFederation.callbacks.trigger(:fetch_private_key_by_diaspora_id, data[:diaspora_id])
           data[:author_signature] = Signing.sign_with_key(data, pkey) unless pkey.nil?
         end
 
         if data[:parent_author_signature].nil?
-          pkey = DiasporaFederation.callbacks.trigger(:fetch_private_key_by_post_guid, data[:parent_guid])
+          pkey = DiasporaFederation.callbacks.trigger(
+            :fetch_author_private_key_by_entity_guid,
+            "Post",
+            data[:parent_guid]
+          )
           data[:parent_author_signature] = Signing.sign_with_key(data, pkey) unless pkey.nil?
         end
       end
diff --git a/lib/diaspora_federation/entities/relayable_retraction.rb b/lib/diaspora_federation/entities/relayable_retraction.rb
index 388ef04..222d86d 100644
--- a/lib/diaspora_federation/entities/relayable_retraction.rb
+++ b/lib/diaspora_federation/entities/relayable_retraction.rb
@@ -22,7 +22,7 @@ module DiasporaFederation
       #   Contains a signature of the entity using the private key of the author of a parent post
       #   This signature is mandatory only when federation from an upstream author to the subscribers.
       #   @return [String] parent author signature
-      property :parent_author_signature
+      property :parent_author_signature, default: nil
 
       # @!attribute [r] target_guid
       #   guid of a post to be deleted
@@ -46,7 +46,45 @@ module DiasporaFederation
       #   This signature is mandatory only when federation from the subscriber to an upstream
       #   author is done.
       #   @return [String] target author signature
-      property :target_author_signature
+      property :target_author_signature, default: nil
+
+      # Generates XML and updates signatures
+      # @see Entity#to_xml
+      # @return [Nokogiri::XML::Element] root element containing properties as child elements
+      def to_xml
+        entity_xml.tap do |xml|
+          hash = to_h
+          RelayableRetraction.update_signatures!(hash)
+          xml.at_xpath("target_author_signature").content = hash[:target_author_signature]
+          xml.at_xpath("parent_author_signature").content = hash[:parent_author_signature]
+        end
+      end
+
+      # Adds signatures to a given hash with the keys of the author and the parent
+      # if the signatures are not in the hash yet and if the keys are available.
+      #
+      # @param [Hash] hash hash given for a signing
+      def self.update_signatures!(hash)
+        target_author = DiasporaFederation.callbacks.trigger(
+          :fetch_entity_author_id_by_guid,
+          hash[:target_type],
+          hash[:target_guid]
+        )
+        pkey = DiasporaFederation.callbacks.trigger(:fetch_private_key_by_diaspora_id, hash[:diaspora_id])
+
+        fill_required_signature(target_author, pkey, hash) unless pkey.nil?
+      end
+
+      def self.fill_required_signature(target_author, pkey, hash)
+        if target_author == hash[:diaspora_id] && hash[:target_author_signature].nil?
+          hash[:target_author_signature] =
+            Signing.sign_with_key(SignedRetraction.apply_signable_exceptions(hash), pkey)
+        elsif target_author != hash[:diaspora_id] && hash[:parent_author_signature].nil?
+          hash[:parent_author_signature] =
+            Signing.sign_with_key(SignedRetraction.apply_signable_exceptions(hash), pkey)
+        end
+      end
+      private_class_method :fill_required_signature
     end
   end
 end
diff --git a/lib/diaspora_federation/entities/signed_retraction.rb b/lib/diaspora_federation/entities/signed_retraction.rb
index e42f6a2..111a429 100644
--- a/lib/diaspora_federation/entities/signed_retraction.rb
+++ b/lib/diaspora_federation/entities/signed_retraction.rb
@@ -25,7 +25,39 @@ module DiasporaFederation
       #   Contains a signature of the entity using the private key of the author of a post
       #   This signature is mandatory.
       #   @return [String] author signature
-      property :target_author_signature
+      property :target_author_signature, default: nil
+
+      # Generates XML and updates signatures
+      # @see Entity#to_xml
+      # @return [Nokogiri::XML::Element] root element containing properties as child elements
+      def to_xml
+        entity_xml.tap do |xml|
+          hash = to_h
+          SignedRetraction.update_signatures!(hash)
+
+          xml.at_xpath("target_author_signature").content = hash[:target_author_signature]
+        end
+      end
+
+      # Adds signature to a given hash with the key of the author
+      # if the signature is not in the hash yet and if the key is available.
+      #
+      # @param [Hash] data hash given for a signing
+      def self.update_signatures!(data)
+        if data[:target_author_signature].nil?
+          pkey = DiasporaFederation.callbacks.trigger(:fetch_private_key_by_diaspora_id, data[:diaspora_id])
+          data[:target_author_signature] = Signing.sign_with_key(apply_signable_exceptions(data), pkey) unless pkey.nil?
+        end
+      end
+
+      # Deletes :diaspora_id (xml_name: sender_handle) from the hash in order to compute
+      # a signature since it is included from signable_string for SignedRetraction and RelayableRetraction
+      #
+      # @param [Hash] data hash of the retraction properties
+      # @retrun [Hash] hash copy without :diaspora_id member
+      def self.apply_signable_exceptions(data)
+        data.dup.tap {|data| data.delete(:diaspora_id) }
+      end
     end
   end
 end
diff --git a/lib/diaspora_federation/test.rb b/lib/diaspora_federation/test.rb
index cac96f1..d9d8ef9 100644
--- a/lib/diaspora_federation/test.rb
+++ b/lib/diaspora_federation/test.rb
@@ -26,5 +26,29 @@ module DiasporaFederation
         DiasporaFederation::Entities::Relayable.update_signatures!(data)
       end
     end
+
+    # Generates attributes for signed retraction entity constructor with correct signatures in it
+    #
+    # @return [Hash] hash with correct signatures
+    def self.signed_retraction_attributes_with_signatures
+      sort_hash(FactoryGirl.attributes_for(:signed_retraction_entity), Entities::SignedRetraction).tap do |data|
+        Entities::SignedRetraction.update_signatures!(data)
+      end
+    end
+
+    # Generates attributes for relayable retraction entity constructor with correct signatures in it
+    #
+    # @return [Hash] hash with correct signatures
+    def self.relayable_retraction_attributes_with_signatures
+      sort_hash(
+        FactoryGirl.attributes_for(
+          :relayable_retraction_entity,
+          target_author_signature: "false sig"
+        ),
+        Entities::RelayableRetraction
+      ).tap do |data|
+        Entities::RelayableRetraction.update_signatures!(data)
+      end
+    end
   end
 end
diff --git a/lib/diaspora_federation/test/factories.rb b/lib/diaspora_federation/test/factories.rb
index 9b3b89a..c54ee50 100644
--- a/lib/diaspora_federation/test/factories.rb
+++ b/lib/diaspora_federation/test/factories.rb
@@ -5,11 +5,6 @@ FactoryGirl.define do
   sequence(:guid) { UUID.generate :compact }
   sequence(:diaspora_id) {|n| "person-#{n}-#{SecureRandom.hex(3)}@localhost:3000" }
   sequence(:public_key) { OpenSSL::PKey::RSA.generate(1024).public_key.export }
-  sequence(:signature) do |i|
-    abc = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
-    ltr = abc[i % abc.length]
-    "#{ltr * 6}=="
-  end
 
   factory :webfinger, class: DiasporaFederation::Discovery::WebFinger do
     guid
@@ -140,11 +135,9 @@ FactoryGirl.define do
   end
 
   factory :relayable_retraction_entity, class: DiasporaFederation::Entities::RelayableRetraction do
-    parent_author_signature { generate(:signature) }
     target_guid { generate(:guid) }
-    target_type "Post"
+    target_type "Comment"
     diaspora_id
-    target_author_signature { generate(:signature) }
   end
 
   factory :reshare_entity, class: DiasporaFederation::Entities::Reshare do
@@ -167,7 +160,6 @@ FactoryGirl.define do
     target_guid { generate(:guid) }
     target_type "Post"
     diaspora_id
-    target_author_signature { generate(:signature) }
   end
 
   factory :poll_answer_entity, class: DiasporaFederation::Entities::PollAnswer do
diff --git a/lib/diaspora_federation/validators/relayable_retraction_validator.rb b/lib/diaspora_federation/validators/relayable_retraction_validator.rb
index 5552e1f..4b647af 100644
--- a/lib/diaspora_federation/validators/relayable_retraction_validator.rb
+++ b/lib/diaspora_federation/validators/relayable_retraction_validator.rb
@@ -4,15 +4,11 @@ module DiasporaFederation
     class RelayableRetractionValidator < Validation::Validator
       include Validation
 
-      rule :parent_author_signature, :not_empty
-
       rule :target_guid, :guid
 
       rule :target_type, :not_empty
 
       rule :diaspora_id, %i(not_empty diaspora_id)
-
-      rule :target_author_signature, :not_empty
     end
   end
 end
diff --git a/lib/diaspora_federation/validators/signed_retraction_validator.rb b/lib/diaspora_federation/validators/signed_retraction_validator.rb
index 54f3fdc..d8442b5 100644
--- a/lib/diaspora_federation/validators/signed_retraction_validator.rb
+++ b/lib/diaspora_federation/validators/signed_retraction_validator.rb
@@ -9,8 +9,6 @@ module DiasporaFederation
       rule :target_type, :not_empty
 
       rule :diaspora_id, %i(not_empty diaspora_id)
-
-      rule :target_author_signature, :not_empty
     end
   end
 end
diff --git a/spec/lib/diaspora_federation/entities/relayable_retraction_spec.rb b/spec/lib/diaspora_federation/entities/relayable_retraction_spec.rb
index d7a0b94..f980c76 100644
--- a/spec/lib/diaspora_federation/entities/relayable_retraction_spec.rb
+++ b/spec/lib/diaspora_federation/entities/relayable_retraction_spec.rb
@@ -1,6 +1,6 @@
 module DiasporaFederation
   describe Entities::RelayableRetraction do
-    let(:data) { FactoryGirl.attributes_for(:relayable_retraction_entity) }
+    let(:data) { Test.relayable_retraction_attributes_with_signatures }
 
     let(:xml) {
       <<-XML
@@ -17,5 +17,70 @@ XML
     it_behaves_like "an Entity subclass"
 
     it_behaves_like "an XML Entity"
+
+    describe ".update_singatures!" do
+      let(:author_pkey) { OpenSSL::PKey::RSA.generate(1024) }
+      let(:hash) { FactoryGirl.attributes_for(:relayable_retraction_entity) }
+
+      it "updates author signature when it was nil and key was supplied" do
+        expect(DiasporaFederation.callbacks).to receive(:trigger)
+                                                  .with(
+                                                    :fetch_entity_author_id_by_guid,
+                                                    hash[:target_type],
+                                                    hash[:target_guid]
+                                                  )
+                                                  .and_return(hash[:diaspora_id])
+        expect(DiasporaFederation.callbacks).to receive(:trigger)
+                                                  .with(:fetch_private_key_by_diaspora_id, hash[:diaspora_id])
+                                                  .and_return(author_pkey)
+
+        Entities::RelayableRetraction.update_signatures!(hash)
+
+        signable_hash = hash.select do |key, _|
+          %i(target_guid target_type).include?(key)
+        end
+        expect(Signing.verify_signature(signable_hash, hash[:target_author_signature], author_pkey)).to be_truthy
+      end
+
+      it "updates parent author signature when it was nil, key was supplied and sender is not author of the target" do
+        expect(DiasporaFederation.callbacks).to receive(:trigger)
+                                                  .with(
+                                                    :fetch_entity_author_id_by_guid,
+                                                    hash[:target_type],
+                                                    hash[:target_guid]
+                                                  )
+                                                  .and_return(FactoryGirl.generate(:diaspora_id))
+        expect(DiasporaFederation.callbacks).to receive(:trigger)
+                                                  .with(:fetch_private_key_by_diaspora_id, hash[:diaspora_id])
+                                                  .and_return(author_pkey)
+
+        Entities::RelayableRetraction.update_signatures!(hash)
+
+        signable_hash = hash.select do |key, _|
+          %i(target_guid target_type).include?(key)
+        end
+        expect(Signing.verify_signature(signable_hash, hash[:parent_author_signature], author_pkey)).to be_truthy
+      end
+
+      it "doesn't change signatures if they are already set" do
+        signatures = {target_author_signature: "aa"}
+        hash.merge!(signatures)
+
+        Entities::RelayableRetraction.update_signatures!(hash)
+        expect(hash[:target_author_signature]).to eq(signatures[:target_author_signature])
+      end
+
+      it "doesn't change signatures if keys weren't supplied" do
+        expect(DiasporaFederation.callbacks).to receive(:trigger)
+                                                  .with(:fetch_private_key_by_diaspora_id, hash[:diaspora_id])
+                                                  .and_return(nil)
+        expect(DiasporaFederation.callbacks).to receive(:trigger)
+                                                  .with(:fetch_entity_author_id_by_guid, "Comment", hash[:target_guid])
+                                                  .and_return(hash[:diaspora_id])
+
+        Entities::RelayableRetraction.update_signatures!(hash)
+        expect(hash[:target_author_signature]).to eq(nil)
+      end
+    end
   end
 end
diff --git a/spec/lib/diaspora_federation/entities/relayable_spec.rb b/spec/lib/diaspora_federation/entities/relayable_spec.rb
index a906b10..3757627 100644
--- a/spec/lib/diaspora_federation/entities/relayable_spec.rb
+++ b/spec/lib/diaspora_federation/entities/relayable_spec.rb
@@ -15,18 +15,24 @@ module DiasporaFederation
         hash[:author_signature] = Signing.sign_with_key(hash, author_pkey)
         hash[:parent_author_signature] = Signing.sign_with_key(hash, parent_pkey)
 
-        expect(DiasporaFederation.callbacks).to receive(:trigger).with(:fetch_public_key_by_id, hash[:diaspora_id])
+        expect(DiasporaFederation.callbacks).to receive(:trigger)
+                                                  .with(:fetch_public_key_by_diaspora_id, hash[:diaspora_id])
                                                   .and_return(author_pkey.public_key)
         expect(DiasporaFederation.callbacks).to receive(:trigger)
-                                                  .with(:fetch_public_key_by_post_guid, hash[:parent_guid])
+                                                  .with(
+                                                    :fetch_author_public_key_by_entity_guid,
+                                                    "Post",
+                                                    hash[:parent_guid]
+                                                  )
                                                   .and_return(parent_pkey.public_key)
-        expect(DiasporaFederation.callbacks).to receive(:trigger).with(:post_author_is_local?, hash[:parent_guid])
+        expect(DiasporaFederation.callbacks).to receive(:trigger)
+                                                  .with(:entity_author_is_local?, "Post", hash[:parent_guid])
                                                   .and_return(false)
         expect { Entities::Relayable.verify_signatures(hash) }.not_to raise_error
       end
 
       it "raises when no public key for author was fetched" do
-        expect(DiasporaFederation.callbacks).to receive(:trigger).with(:fetch_public_key_by_id, anything)
+        expect(DiasporaFederation.callbacks).to receive(:trigger).with(:fetch_public_key_by_diaspora_id, anything)
                                                   .and_return(nil)
 
         expect { Entities::Relayable.verify_signatures(hash) }.to raise_error(
@@ -37,7 +43,8 @@ module DiasporaFederation
       it "raises when bad author signature was passed" do
         hash[:author_signature] = nil
 
-        expect(DiasporaFederation.callbacks).to receive(:trigger).with(:fetch_public_key_by_id, hash[:diaspora_id])
+        expect(DiasporaFederation.callbacks).to receive(:trigger)
+                                                  .with(:fetch_public_key_by_diaspora_id, hash[:diaspora_id])
                                                   .and_return(author_pkey.public_key)
         expect { Entities::Relayable.verify_signatures(hash) }.to raise_error(
           Entities::Relayable::SignatureVerificationFailed
@@ -47,12 +54,18 @@ module DiasporaFederation
       it "raises when no public key for parent author was fetched" do
         hash[:author_signature] = Signing.sign_with_key(hash, author_pkey)
 
-        expect(DiasporaFederation.callbacks).to receive(:trigger).with(:fetch_public_key_by_id, hash[:diaspora_id])
+        expect(DiasporaFederation.callbacks).to receive(:trigger)
+                                                  .with(:fetch_public_key_by_diaspora_id, hash[:diaspora_id])
                                                   .and_return(author_pkey.public_key)
         expect(DiasporaFederation.callbacks).to receive(:trigger)
-                                                  .with(:fetch_public_key_by_post_guid, hash[:parent_guid])
+                                                  .with(
+                                                    :fetch_author_public_key_by_entity_guid,
+                                                    "Post",
+                                                    hash[:parent_guid]
+                                                  )
                                                   .and_return(nil)
-        expect(DiasporaFederation.callbacks).to receive(:trigger).with(:post_author_is_local?, hash[:parent_guid])
+        expect(DiasporaFederation.callbacks).to receive(:trigger)
+                                                  .with(:entity_author_is_local?, "Post", hash[:parent_guid])
                                                   .and_return(false)
         expect { Entities::Relayable.verify_signatures(hash) }.to raise_error(
           Entities::Relayable::SignatureVerificationFailed
@@ -63,12 +76,18 @@ module DiasporaFederation
         hash[:author_signature] = Signing.sign_with_key(hash, author_pkey)
         hash[:parent_author_signature] = nil
 
-        expect(DiasporaFederation.callbacks).to receive(:trigger).with(:fetch_public_key_by_id, hash[:diaspora_id])
+        expect(DiasporaFederation.callbacks).to receive(:trigger)
+                                                  .with(:fetch_public_key_by_diaspora_id, hash[:diaspora_id])
                                                   .and_return(author_pkey.public_key)
         expect(DiasporaFederation.callbacks).to receive(:trigger)
-                                                  .with(:fetch_public_key_by_post_guid, hash[:parent_guid])
+                                                  .with(
+                                                    :fetch_author_public_key_by_entity_guid,
+                                                    "Post",
+                                                    hash[:parent_guid]
+                                                  )
                                                   .and_return(parent_pkey.public_key)
-        expect(DiasporaFederation.callbacks).to receive(:trigger).with(:post_author_is_local?, hash[:parent_guid])
+        expect(DiasporaFederation.callbacks).to receive(:trigger)
+                                                  .with(:entity_author_is_local?, "Post", hash[:parent_guid])
                                                   .and_return(false)
         expect { Entities::Relayable.verify_signatures(hash) }.to raise_error(
           Entities::Relayable::SignatureVerificationFailed
@@ -79,9 +98,11 @@ module DiasporaFederation
         hash[:author_signature] = Signing.sign_with_key(hash, author_pkey)
         hash[:parent_author_signature] = nil
 
-        expect(DiasporaFederation.callbacks).to receive(:trigger).with(:fetch_public_key_by_id, hash[:diaspora_id])
+        expect(DiasporaFederation.callbacks).to receive(:trigger)
+                                                  .with(:fetch_public_key_by_diaspora_id, hash[:diaspora_id])
                                                   .and_return(author_pkey.public_key)
-        expect(DiasporaFederation.callbacks).to receive(:trigger).with(:post_author_is_local?, hash[:parent_guid])
+        expect(DiasporaFederation.callbacks).to receive(:trigger)
+                                                  .with(:entity_author_is_local?, "Post", hash[:parent_guid])
                                                   .and_return(true)
         expect { Entities::Relayable.verify_signatures(hash) }.not_to raise_error
       end
@@ -89,10 +110,15 @@ module DiasporaFederation
 
     describe ".update_singatures!" do
       it "updates signatures when they were nil and keys were supplied" do
-        expect(DiasporaFederation.callbacks).to receive(:trigger).with(:fetch_private_key_by_id, hash[:diaspora_id])
+        expect(DiasporaFederation.callbacks).to receive(:trigger)
+                                                  .with(:fetch_private_key_by_diaspora_id, hash[:diaspora_id])
                                                   .and_return(author_pkey)
         expect(DiasporaFederation.callbacks).to receive(:trigger)
-                                                  .with(:fetch_private_key_by_post_guid, hash[:parent_guid])
+                                                  .with(
+                                                    :fetch_author_private_key_by_entity_guid,
+                                                    "Post",
+                                                    hash[:parent_guid]
+                                                  )
                                                   .and_return(parent_pkey)
 
         Entities::Relayable.update_signatures!(hash)
@@ -110,10 +136,15 @@ module DiasporaFederation
       end
 
       it "doesn't change signatures if keys weren't supplied" do
-        expect(DiasporaFederation.callbacks).to receive(:trigger).with(:fetch_private_key_by_id, hash[:diaspora_id])
+        expect(DiasporaFederation.callbacks).to receive(:trigger)
+                                                  .with(:fetch_private_key_by_diaspora_id, hash[:diaspora_id])
                                                   .and_return(nil)
         expect(DiasporaFederation.callbacks).to receive(:trigger)
-                                                  .with(:fetch_private_key_by_post_guid, hash[:parent_guid])
+                                                  .with(
+                                                    :fetch_author_private_key_by_entity_guid,
+                                                    "Post",
+                                                    hash[:parent_guid]
+                                                  )
                                                   .and_return(nil)
 
         Entities::Relayable.update_signatures!(hash)
diff --git a/spec/lib/diaspora_federation/entities/signed_retraction_spec.rb b/spec/lib/diaspora_federation/entities/signed_retraction_spec.rb
index 79a1d3f..f4f6aea 100644
--- a/spec/lib/diaspora_federation/entities/signed_retraction_spec.rb
+++ b/spec/lib/diaspora_federation/entities/signed_retraction_spec.rb
@@ -1,6 +1,6 @@
 module DiasporaFederation
   describe Entities::SignedRetraction do
-    let(:data) { FactoryGirl.attributes_for(:signed_retraction_entity) }
+    let(:data) { Test.signed_retraction_attributes_with_signatures }
 
     let(:xml) {
       <<-XML
@@ -16,5 +16,41 @@ XML
     it_behaves_like "an Entity subclass"
 
     it_behaves_like "an XML Entity"
+
+    describe ".update_singatures!" do
+      let(:author_pkey) { OpenSSL::PKey::RSA.generate(1024) }
+      let(:hash) { FactoryGirl.attributes_for(:signed_retraction_entity) }
+
+      it "updates author signature when it was nil and key was supplied" do
+        expect(DiasporaFederation.callbacks).to receive(:trigger)
+                                                  .with(:fetch_private_key_by_diaspora_id, hash[:diaspora_id])
+                                                  .and_return(author_pkey)
+
+        signable_hash = hash.select do |key, _|
+          %i(target_guid target_type).include?(key)
+        end
+
+        Entities::SignedRetraction.update_signatures!(hash)
+
+        expect(Signing.verify_signature(signable_hash, hash[:target_author_signature], author_pkey)).to be_truthy
+      end
+
+      it "doesn't change signature if it is already set" do
+        signatures = {target_author_signature: "aa"}
+        hash.merge!(signatures)
+
+        Entities::SignedRetraction.update_signatures!(hash)
+        expect(hash[:target_author_signature]).to eq(signatures[:target_author_signature])
+      end
+
+      it "doesn't change signature if a key wasn't supplied" do
+        expect(DiasporaFederation.callbacks).to receive(:trigger)
+                                                  .with(:fetch_private_key_by_diaspora_id, hash[:diaspora_id])
+                                                  .and_return(nil)
+
+        Entities::SignedRetraction.update_signatures!(hash)
+        expect(hash[:author_signature]).to eq(nil)
+      end
+    end
   end
 end
diff --git a/spec/lib/diaspora_federation/validators/relayable_retraction_validator_spec.rb b/spec/lib/diaspora_federation/validators/relayable_retraction_validator_spec.rb
index a21d9dd..3330f16 100644
--- a/spec/lib/diaspora_federation/validators/relayable_retraction_validator_spec.rb
+++ b/spec/lib/diaspora_federation/validators/relayable_retraction_validator_spec.rb
@@ -12,11 +12,9 @@ module DiasporaFederation
       let(:property) { :target_guid }
     end
 
-    %i(parent_author_signature target_author_signature).each do |prop|
-      describe "##{prop}" do
-        it_behaves_like "a property that mustn't be empty" do
-          let(:property) { prop }
-        end
+    describe "#target_type" do
+      it_behaves_like "a property that mustn't be empty" do
+        let(:property) { :target_type }
       end
     end
   end
diff --git a/spec/lib/diaspora_federation/validators/signed_retraction_validator_spec.rb b/spec/lib/diaspora_federation/validators/signed_retraction_validator_spec.rb
index 9cebde0..3771290 100644
--- a/spec/lib/diaspora_federation/validators/signed_retraction_validator_spec.rb
+++ b/spec/lib/diaspora_federation/validators/signed_retraction_validator_spec.rb
@@ -12,11 +12,9 @@ module DiasporaFederation
       let(:property) { :target_guid }
     end
 
-    %i(target_type target_author_signature).each do |prop|
-      describe "##{prop}" do
-        it_behaves_like "a property that mustn't be empty" do
-          let(:property) { prop }
-        end
+    describe "#target_type" do
+      it_behaves_like "a property that mustn't be empty" do
+        let(:property) { :target_type }
       end
     end
   end
diff --git a/spec/spec_helper.rb b/spec/spec_helper.rb
index 0f5db42..6faab55 100644
--- a/spec/spec_helper.rb
+++ b/spec/spec_helper.rb
@@ -35,7 +35,7 @@ def alice
 end
 
 def test_pkey
-  DiasporaFederation.callbacks.trigger(:fetch_private_key_by_id)
+  DiasporaFederation.callbacks.trigger(:fetch_private_key_by_diaspora_id)
 end
 
 # Requires supporting files with custom matchers and macros, etc,
diff --git a/test/dummy/config/initializers/diaspora_federation.rb b/test/dummy/config/initializers/diaspora_federation.rb
index bfd817e..95a8ed4 100644
--- a/test/dummy/config/initializers/diaspora_federation.rb
+++ b/test/dummy/config/initializers/diaspora_federation.rb
@@ -63,24 +63,28 @@ DiasporaFederation.configure do |config|
       @test_pkey ||= OpenSSL::PKey::RSA.generate(1024)
     end
 
-    on :fetch_private_key_by_id do
+    on :fetch_private_key_by_diaspora_id do
       pkey
     end
 
-    on :fetch_private_key_by_post_guid do
+    on :fetch_author_private_key_by_entity_guid do
       pkey
     end
 
-    on :fetch_public_key_by_id do
+    on :fetch_public_key_by_diaspora_id do
       pkey.public_key
     end
 
-    on :fetch_public_key_by_post_guid do
+    on :fetch_author_public_key_by_entity_guid do
       pkey.public_key
     end
 
-    on :post_author_is_local? do
+    on :entity_author_is_local? do
       false
     end
+
+    on :fetch_entity_author_id_by_guid do
+      nil
+    end
   end
 end