Filter out old system notes for epics

7 files changed, 21 insertions, 8 deletions

diff --git a/app/controllers/concerns/issuable_actions.rb b/app/controllers/concerns/issuable_actions.rb
index 6fa2f75be33..0287380fb1b 100644
--- a/app/controllers/concerns/issuable_actions.rb
+++ b/app/controllers/concerns/issuable_actions.rb
@@ -111,7 +111,7 @@ module IssuableActions
     end
 
     notes = prepare_notes_for_rendering(notes)
-    notes = notes.reject { |n| n.cross_reference_not_visible_for?(current_user) }
+    notes = notes.select { |n| n.visible_for?(current_user) }
 
     discussions = Discussion.build_collection(notes, issuable)
 
diff --git a/app/controllers/concerns/notes_actions.rb b/app/controllers/concerns/notes_actions.rb
index 0098c4cdf4c..52c3a34ffe4 100644
--- a/app/controllers/concerns/notes_actions.rb
+++ b/app/controllers/concerns/notes_actions.rb
@@ -29,7 +29,7 @@ module NotesActions
     end
 
     notes = prepare_notes_for_rendering(notes)
-    notes = notes.reject { |n| n.cross_reference_not_visible_for?(current_user) }
+    notes = notes.select { |n| n.visible_for?(current_user) }
 
     notes_json[:notes] =
       if use_note_serializer?
diff --git a/app/models/note.rb b/app/models/note.rb
index 5c31cff9816..9485f1037c1 100644
--- a/app/models/note.rb
+++ b/app/models/note.rb
@@ -327,6 +327,10 @@ class Note < ApplicationRecord
     cross_reference? && !all_referenced_mentionables_allowed?(user)
   end
 
+  def visible_for?(user)
+    !cross_reference_not_visible_for?(user)
+  end
+
   def award_emoji?
     can_be_award_emoji? && contains_emoji_only?
   end
diff --git a/changelogs/unreleased/security-epic-notes-api-reveals-historical-info-ce-master.yml b/changelogs/unreleased/security-epic-notes-api-reveals-historical-info-ce-master.yml
new file mode 100644
index 00000000000..c639098721e
--- /dev/null
+++ b/changelogs/unreleased/security-epic-notes-api-reveals-historical-info-ce-master.yml
@@ -0,0 +1,5 @@
+---
+title: Filter out old system notes for epics in notes api endpoint response
+merge_request:
+author:
+type: security
diff --git a/lib/api/discussions.rb b/lib/api/discussions.rb
index cc62ce22a1b..3fb70024201 100644
--- a/lib/api/discussions.rb
+++ b/lib/api/discussions.rb
@@ -32,7 +32,7 @@ module API
             .includes(:noteable)
             .fresh
 
-          notes = notes.reject { |n| n.cross_reference_not_visible_for?(current_user) }
+          notes = notes.select { |n| n.visible_for?(current_user) }
           discussions = Kaminari.paginate_array(Discussion.build_collection(notes, noteable))
 
           present paginate(discussions), with: Entities::Discussion
@@ -233,7 +233,7 @@ module API
           .includes(:noteable)
           .fresh
 
-        notes.reject { |n| n.cross_reference_not_visible_for?(current_user) }
+        notes.select { |n| n.visible_for?(current_user) }
       end
       # rubocop: enable CodeReuse/ActiveRecord
     end
diff --git a/lib/api/helpers/notes_helpers.rb b/lib/api/helpers/notes_helpers.rb
index b03ac7deb71..d1de156376c 100644
--- a/lib/api/helpers/notes_helpers.rb
+++ b/lib/api/helpers/notes_helpers.rb
@@ -10,7 +10,7 @@ module API
       end
 
       def update_note(noteable, note_id)
-        note = noteable.notes.find(params[:note_id])
+        note = noteable.notes.find(note_id)
 
         authorize! :admin_note, note
 
@@ -59,8 +59,8 @@ module API
       end
 
       def get_note(noteable, note_id)
-        note = noteable.notes.with_metadata.find(params[:note_id])
-        can_read_note = !note.cross_reference_not_visible_for?(current_user)
+        note = noteable.notes.with_metadata.find(note_id)
+        can_read_note = note.visible_for?(current_user)
 
         if can_read_note
           present note, with: Entities::Note
@@ -81,6 +81,10 @@ module API
         noteable || not_found!(noteable_type)
       end
 
+      def reject_note?(noteable_type, noteable, parent_type, parent_id, note)
+        note.cross_reference_not_visible_for?(current_user)
+      end
+
       def params_by_noteable_type_and_id(type, id)
         target_type = type.name.underscore
         { target_type: target_type }.tap do |h|
diff --git a/lib/api/notes.rb b/lib/api/notes.rb
index 9381f045144..eaf97bb119e 100644
--- a/lib/api/notes.rb
+++ b/lib/api/notes.rb
@@ -41,7 +41,7 @@ module API
             # mismatch between the pagination headers info and the actual notes
             # array returned, but this is really a edge-case.
             paginate(raw_notes)
-            .reject { |n| n.cross_reference_not_visible_for?(current_user) }
+            .select { |note| note.visible_for?(current_user) }
           present notes, with: Entities::Note
         end
         # rubocop: enable CodeReuse/ActiveRecord