FIX: only admin can edit faq, tos, and privacy policy

lib/discourse.rb

@@ -265,4 +265,8 @@ module Discourse
     { url: $redis.url, namespace: 'sidekiq' }
   end
 
+  def self.static_doc_topic_ids
+    [SiteSetting.tos_topic_id, SiteSetting.guidelines_topic_id, SiteSetting.privacy_topic_id]
+  end
+
 end

lib/guardian/post_guardian.rb

@@ -72,6 +72,10 @@ module PostGuardian
 
   # Editing Method
   def can_edit_post?(post)
+    if Discourse.static_doc_topic_ids.include?(post.topic_id) && !is_admin?
+      return false
+    end
+
     if is_staff? || @user.has_trust_level?(:elder)
       return true
     end

lib/guardian/topic_guardian.rb

@@ -27,7 +27,10 @@ module TopicGuardian
 
   # Editing Method
   def can_edit_topic?(topic)
-    !topic.archived && (is_staff? || is_my_own?(topic) || user.has_trust_level?(:leader))
+    return false if topic.archived
+    return true if is_my_own?(topic)
+    return false if Discourse.static_doc_topic_ids.include?(topic.id) && !is_admin?
+    is_staff? || user.has_trust_level?(:leader)
   end
 
   # Recovery Method

spec/components/guardian_spec.rb

@@ -354,6 +354,15 @@ describe Guardian do
         Guardian.new(moderator).can_see?(private_topic).should be_false
         Guardian.new(admin).can_see?(private_topic).should be_true
       end
+
+      it "restricts static doc topics" do
+        tos_topic = Fabricate(:topic, user: Discourse.system_user)
+        SiteSetting.stubs(:tos_topic_id).returns(tos_topic.id)
+
+        Guardian.new(build(:user)).can_edit?(tos_topic).should be_false
+        Guardian.new(moderator).can_edit?(tos_topic).should be_false
+        Guardian.new(admin).can_edit?(tos_topic).should be_true
+      end
     end
 
     describe 'a Post' do
@@ -784,6 +793,18 @@ describe Guardian do
           Guardian.new(post.user).can_edit?(post).should be_true
         end
       end
+
+      context "first post of a static page doc" do
+        let!(:tos_topic) { Fabricate(:topic, user: Discourse.system_user) }
+        let!(:tos_first_post) { build(:post, topic: tos_topic, user: tos_topic.user) }
+        before { SiteSetting.stubs(:tos_topic_id).returns(tos_topic.id) }
+
+        it "restricts static doc posts" do
+          Guardian.new(build(:user)).can_edit?(tos_first_post).should be_false
+          Guardian.new(moderator).can_edit?(tos_first_post).should be_false
+          Guardian.new(admin).can_edit?(tos_first_post).should be_true
+        end
+      end
     end
 
     describe 'a Topic' do