Fix link verification for remote accounts (#8868)

app/models/account.rb

@@ -312,8 +312,8 @@ class Account < ApplicationRecord
     def initialize(account, attributes)
       @account     = account
       @attributes  = attributes
-      @name        = attributes['name'].strip[0, 255]
-      @value       = attributes['value'].strip[0, 255]
+      @name        = attributes['name'].strip[0, string_limit]
+      @value       = attributes['value'].strip[0, string_limit]
       @verified_at = attributes['verified_at']&.to_datetime
       @errors      = {}
     end
@@ -322,8 +322,18 @@ class Account < ApplicationRecord
       verified_at.present?
     end
 
+    def value_for_verification
+      @value_for_verification ||= begin
+        if account.local?
+          value
+        else
+          ActionController::Base.helpers.strip_tags(value)
+        end
+      end
+    end
+
     def verifiable?
-      value.present? && value.start_with?('http://', 'https://')
+      value_for_verification.present? && value_for_verification.start_with?('http://', 'https://')
     end
 
     def mark_verified!
@@ -334,6 +344,16 @@ class Account < ApplicationRecord
     def to_h
       { name: @name, value: @value, verified_at: @verified_at }
     end
+
+    private
+
+    def string_limit
+      if account.local?
+        255
+      else
+        2047
+      end
+    end
   end
 
   class << self

app/serializers/rest/account_serializer.rb

@@ -11,11 +11,7 @@ class REST::AccountSerializer < ActiveModel::Serializer
   has_many :emojis, serializer: REST::CustomEmojiSerializer
 
   class FieldSerializer < ActiveModel::Serializer
-    attributes :name, :value
-
-    attribute :verified_at, if: :verifiable?
-
-    delegate :verifiable?, to: :object
+    attributes :name, :value, :verified_at
 
     def value
       Formatter.instance.format_field(object.account, object.value)

app/services/verify_link_service.rb

@@ -3,7 +3,7 @@
 class VerifyLinkService < BaseService
   def call(field)
     @link_back = ActivityPub::TagManager.instance.url_for(field.account)
-    @url       = field.value
+    @url       = field.value_for_verification
 
     perform_request!