HDFS-16766. XML External Entity (XXE) attacks can occur while processing XML received from an untrusted source (#4886)

Co-authored-by: Ashutosh Gupta <ashugpt@amazon.com>
Signed-off-by: Akira Ajisaka <aajisaka@apache.org>
(cherry picked from commit d9f435f6acabb28ab8a670a4a9081f0164008b1e)

hadoop-hdfs-project/hadoop-hdfs-client/src/main/java/org/apache/hadoop/hdfs/util/ECPolicyLoader.java

@@ -89,6 +89,11 @@ public class ECPolicyLoader {
     // Read and parse the EC policy file.
     DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
     dbf.setIgnoringComments(true);
+    dbf.setFeature("http://apache.org/xml/features/disallow-doctype-decl", true);
+    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("http://apache.org/xml/features/dom/create-entity-ref-nodes", false);
     DocumentBuilder builder = dbf.newDocumentBuilder();
     Document doc = builder.parse(policyFile);
     Element root = doc.getDocumentElement();