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JDOM XXE Protection [CVE-2013-1856]

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1 parent 8be6913 commit db8b636e50ee8a138f48117e8e8ad057cc7527a4 @benmmurphy benmmurphy committed with tenderlove Feb 8, 2013
@@ -37,6 +37,12 @@ def parse(data)
{}
else
@dbf = DocumentBuilderFactory.new_instance
+ # secure processing of java xml
+ # http://www.ibm.com/developerworks/xml/library/x-tipcfsx/index.html
+ @dbf.setFeature("http://apache.org/xml/features/nonvalidating/load-external-dtd", false)
+ @dbf.setFeature("http://xml.org/sax/features/external-general-entities", false)
+ @dbf.setFeature("http://xml.org/sax/features/external-parameter-entities", false)
+ @dbf.setFeature(javax.xml.XMLConstants::FEATURE_SECURE_PROCESSING, true)
xml_string_reader = StringReader.new(data)
xml_input_source = InputSource.new(xml_string_reader)
doc = @dbf.new_document_builder.parse(xml_input_source)
@@ -0,0 +1 @@
+<!ENTITY a "external entity">
@@ -0,0 +1 @@
+<!ENTITY a "hello">
@@ -0,0 +1 @@
+include me
@@ -3,9 +3,12 @@
require 'active_support/xml_mini'
require 'active_support/core_ext/hash/conversions'
+
class JDOMEngineTest < ActiveSupport::TestCase
include ActiveSupport
+ FILES_DIR = File.dirname(__FILE__) + '/../fixtures/xml'
+
def setup
@default_backend = XmlMini.backend
XmlMini.backend = 'JDOM'
@@ -30,10 +33,41 @@ def test_file_from_xml
assert_equal 'image/png', file.content_type
end
+ def test_not_allowed_to_expand_entities_to_files
+ attack_xml = <<-EOT
+ <!DOCTYPE member [
+ <!ENTITY a SYSTEM "file://#{FILES_DIR}/jdom_include.txt">
+ ]>
+ <member>x&a;</member>
+ EOT
+ assert_equal 'x', Hash.from_xml(attack_xml)["member"]
+ end
+
+ def test_not_allowed_to_expand_parameter_entities_to_files
+ attack_xml = <<-EOT
+ <!DOCTYPE member [
+ <!ENTITY % b SYSTEM "file://#{FILES_DIR}/jdom_entities.txt">
+ %b;
+ ]>
+ <member>x&a;</member>
+ EOT
+ assert_raise Java::OrgXmlSax::SAXParseException do
+ assert_equal 'x', Hash.from_xml(attack_xml)["member"]
+ end
+ end
+
+
+ def test_not_allowed_to_load_external_doctypes
+ attack_xml = <<-EOT
+ <!DOCTYPE member SYSTEM "file://#{FILES_DIR}/jdom_doctype.dtd">
+ <member>x&a;</member>
+ EOT
+ assert_equal 'x', Hash.from_xml(attack_xml)["member"]
+ end
+
def test_exception_thrown_on_expansion_attack
- assert_raise NativeException do
+ assert_raise Java::OrgXmlSax::SAXParseException do
attack_xml = <<-EOT
- <?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE member [
<!ENTITY a "&b;&b;&b;&b;&b;&b;&b;&b;&b;&b;">
<!ENTITY b "&c;&c;&c;&c;&c;&c;&c;&c;&c;&c;">

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