--- /dev/null
+require 'rexml/document'
+require 'rexml/entity'
+
+# Fixes the rexml vulnerability disclosed at:
+# http://www.ruby-lang.org/en/news/2008/08/23/dos-vulnerability-in-rexml/
+# This fix is identical to rexml-expansion-fix version 1.0.1
+
+# Earlier versions of rexml defined REXML::Version, newer ones REXML::VERSION
+unless REXML::Document.respond_to?(:entity_expansion_limit=)
+ module REXML
+ class Entity < Child
+ undef_method :unnormalized
+ def unnormalized
+ document.record_entity_expansion! if document
+ v = value()
+ return nil if v.nil?
+ @unnormalized = Text::unnormalize(v, parent)
+ @unnormalized
+ end
+ end
+ class Document < Element
+ @@entity_expansion_limit = 10_000
+ def self.entity_expansion_limit= val
+ @@entity_expansion_limit = val
+ end
+
+ def record_entity_expansion!
+ @number_of_expansions ||= 0
+ @number_of_expansions += 1
+ if @number_of_expansions > @@entity_expansion_limit
+ raise "Number of entity expansions exceeded, processing aborted."
+ end
+ end
+ end
+ end
+end