Merge pull request from GHSA-c7p6-c688-fhgp

* FixSec: スタンプを経由してカスタム絵文字のデータを改竄できる問題

* Fix: 相乗り絵文字が受け取れない問題とテスト

* Change: 相乗りスタンプは常にオリジナルの情報を参照

* Fix: uriまで偽装した場合に対応

app/lib/activitypub/activity/like.rb

@@ -3,6 +3,7 @@
 class ActivityPub::Activity::Like < ActivityPub::Activity
   include Redisable
   include Lockable
+  include JsonLdHelper
 
   def perform
     @original_status = status_from_uri(object_uri)
@@ -102,7 +103,7 @@ def process_emoji(tag)
 
     return if custom_emoji_parser.shortcode.blank? || custom_emoji_parser.image_remote_url.blank?
 
-    domain = tag['domain'] || URI.split(custom_emoji_parser.uri)[2] || @account.domain
+    domain = URI.split(custom_emoji_parser.uri)[2] || @account.domain
 
     if domain == Rails.configuration.x.local_domain || domain == Rails.configuration.x.web_domain
       # Block overwriting remote-but-local data
@@ -118,6 +119,9 @@ def process_emoji(tag)
                         (custom_emoji_parser.updated_at && custom_emoji_parser.updated_at >= emoji.updated_at) ||
                         custom_emoji_parser.license != emoji.license
 
+    custom_emoji_parser = original_emoji_parser(custom_emoji_parser) if @account.domain != domain
+    return if custom_emoji_parser.nil?
+
     begin
       emoji ||= CustomEmoji.new(
         domain: domain,
@@ -136,6 +140,17 @@ def process_emoji(tag)
     emoji
   end
 
+  def original_emoji_parser(custom_emoji_parser)
+    uri = custom_emoji_parser.uri
+    emoji = fetch_resource_without_id_validation(uri)
+    return nil unless emoji
+
+    parser = ActivityPub::Parser::CustomEmojiParser.new(emoji)
+    return nil unless parser.uri == uri && custom_emoji_parser.shortcode == parser.shortcode
+
+    parser
+  end
+
   def skip_download?(domain)
     DomainBlock.reject_media?(domain)
   end

app/serializers/activitypub/emoji_serializer.rb

@@ -5,7 +5,7 @@ class ActivityPub::EmojiSerializer < ActivityPub::Serializer
 
   context_extensions :emoji, :license, :keywords
 
-  attributes :id, :type, :domain, :name, :keywords, :is_sensitive, :updated
+  attributes :id, :type, :name, :keywords, :is_sensitive, :updated
 
   attribute :license, if: -> { object.license.present? }
 
@@ -19,10 +19,6 @@ def type
     'Emoji'
   end
 
-  def domain
-    object.domain.presence || Rails.configuration.x.local_domain
-  end
-
   def keywords
     object.aliases
   end

spec/lib/activitypub/activity/like_spec.rb

@@ -16,6 +16,28 @@
       object: ActivityPub::TagManager.instance.uri_for(status),
     }.with_indifferent_access
   end
+  let(:original_emoji) do
+    {
+      id: 'https://example.com/aaa',
+      type: 'Emoji',
+      icon: {
+        url: 'http://example.com/emoji.png',
+      },
+      name: 'tinking',
+      license: 'This is ohagi',
+    }
+  end
+  let(:original_invalid_emoji) do
+    {
+      id: 'https://example.com/invalid',
+      type: 'Emoji',
+      icon: {
+        url: 'http://example.com/emoji.png',
+      },
+      name: 'other',
+      license: 'This is other ohagi',
+    }
+  end
 
   describe '#perform' do
     subject { described_class.new(json, sender) }
@@ -37,6 +59,9 @@
 
     before do
       stub_request(:get, 'http://example.com/emoji.png').to_return(body: attachment_fixture('emojo.png'))
+      stub_request(:get, 'http://foo.bar/emoji2.png').to_return(body: attachment_fixture('emojo.png'))
+      stub_request(:get, 'https://example.com/aaa').to_return(status: 200, body: Oj.dump(original_emoji))
+      stub_request(:get, 'https://example.com/invalid').to_return(status: 200, body: Oj.dump(original_invalid_emoji))
     end
 
     let(:json) do
@@ -122,31 +147,111 @@
       end
     end
 
-    context 'with custom emoji and custom domain' do
+    context 'with custom emoji from non-original server account' do
       let(:content) { ':tinking:' }
       let(:tag) do
         {
           id: 'https://example.com/aaa',
           type: 'Emoji',
-          domain: 'post.kmycode.net',
           icon: {
             url: 'http://example.com/emoji.png',
           },
           name: 'tinking',
         }
       end
 
+      before do
+        sender.update(domain: 'ohagi.com')
+        Fabricate(:custom_emoji, domain: 'example.com', uri: 'https://example.com/aaa', shortcode: 'tinking')
+      end
+
       it 'create emoji reaction' do
         expect(subject.count).to eq 1
         expect(subject.first.name).to eq 'tinking'
         expect(subject.first.account).to eq sender
         expect(subject.first.custom_emoji).to_not be_nil
         expect(subject.first.custom_emoji.shortcode).to eq 'tinking'
-        expect(subject.first.custom_emoji.domain).to eq 'post.kmycode.net'
+        expect(subject.first.custom_emoji.domain).to eq 'example.com'
+        expect(sender.favourited?(status)).to be false
+      end
+    end
+
+    context 'with custom emoji and update license from non-original server account' do
+      let(:content) { ':tinking:' }
+      let(:tag) do
+        {
+          id: 'https://example.com/aaa',
+          type: 'Emoji',
+          icon: {
+            url: 'http://example.com/emoji.png',
+          },
+          name: 'tinking',
+          license: 'Old license',
+        }
+      end
+
+      before do
+        sender.update(domain: 'ohagi.com')
+        Fabricate(:custom_emoji, domain: 'example.com', uri: 'https://example.com/aaa', shortcode: 'tinking')
+      end
+
+      it 'create emoji reaction' do
+        expect(subject.count).to eq 1
+        expect(subject.first.custom_emoji.license).to eq 'This is ohagi'
         expect(sender.favourited?(status)).to be false
       end
     end
 
+    context 'with custom emoji but icon url is not valid' do
+      let(:content) { ':tinking:' }
+      let(:tag) do
+        {
+          id: 'https://example.com/aaa',
+          type: 'Emoji',
+          icon: {
+            url: 'http://foo.bar/emoji.png',
+          },
+          name: 'tinking',
+          license: 'Good for using darwin',
+        }
+      end
+
+      before do
+        sender.update(domain: 'ohagi.com')
+        Fabricate(:custom_emoji, domain: 'example.com', uri: 'https://example.com/aaa', shortcode: 'tinking', image_remote_url: 'http://example.com/emoji.png')
+      end
+
+      it 'create emoji reaction' do
+        expect(subject.count).to eq 1
+        expect(subject.first.custom_emoji.reload.license).to eq 'This is ohagi'
+        expect(subject.first.custom_emoji.image_remote_url).to eq 'http://example.com/emoji.png'
+      end
+    end
+
+    context 'with custom emoji but uri is not valid' do
+      let(:content) { ':tinking:' }
+      let(:tag) do
+        {
+          id: 'https://example.com/invalid',
+          type: 'Emoji',
+          icon: {
+            url: 'http://foo.bar/emoji2.png',
+          },
+          name: 'tinking',
+          license: 'Good for using darwin',
+        }
+      end
+
+      before do
+        sender.update(domain: 'ohagi.com')
+        Fabricate(:custom_emoji, domain: 'example.com', uri: 'https://example.com/aaa', shortcode: 'tinking', image_remote_url: 'http://example.com/emoji.png')
+      end
+
+      it 'create emoji reaction' do
+        expect(subject.count).to eq 0
+      end
+    end
+
     context 'with custom emoji but invalid id' do
       let(:content) { ':tinking:' }
       let(:tag) do
@@ -175,7 +280,7 @@
       let(:content) { ':tinking:' }
       let(:tag) do
         {
-          id: 'aaa',
+          id: 'https://cb6e6126.ngrok.io/aaa',
           type: 'Emoji',
           domain: Rails.configuration.x.local_domain,
           icon: {
@@ -197,6 +302,7 @@
         expect(subject.first.custom_emoji).to_not be_nil
         expect(subject.first.custom_emoji.shortcode).to eq 'tinking'
         expect(subject.first.custom_emoji.domain).to be_nil
+        expect(subject.first.custom_emoji.license).to eq 'Everyone but Ohagi'
         expect(sender.favourited?(status)).to be false
       end