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Improved setup for XML parsing #1284

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Merged
labkey-jeckels merged 4 commits into from
Feb 16, 2026
Merged

Improved setup for XML parsing #1284

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536e744
Improved validation for XML parsing and paths
labkey-jeckels Feb 16, 2026
42c4aa5
Comments and consistency
labkey-jeckels Feb 16, 2026
3c06ce2
Fix typo
labkey-jeckels Feb 16, 2026
05e7954
Merge branch 'develop' into fb_miscCleanup
labkey-jeckels Feb 16, 2026
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10 changes: 9 additions & 1 deletion server/bootstrap/src/org/labkey/bootstrap/ModuleArchive.java
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Original file line number Diff line number Diff line change
Expand Up @@ -19,6 +19,7 @@
import org.xml.sax.SAXException;
import org.xml.sax.helpers.DefaultHandler;

import javax.xml.XMLConstants;
import javax.xml.parsers.ParserConfigurationException;
import javax.xml.parsers.SAXParser;
import javax.xml.parsers.SAXParserFactory;
Expand Down Expand Up @@ -71,7 +72,14 @@ private String nameFromModuleXML(InputStream is) throws IOException

try
{
SAXParser parser = SAXParserFactory.newDefaultInstance().newSAXParser();
// Keep this in sync with config on XmlBeansUtil.SAX_PARSER_FACTORY. See motiviations in comments there.
SAXParserFactory factory = SAXParserFactory.newDefaultInstance();
factory.setFeature("http://apache.org/xml/features/disallow-doctype-decl", true);
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@labkey-alan labkey-alan Feb 16, 2026

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According to this blog post I found from 2012 these settings seem to be mutually exclusive. My understanding is that you need to either disable doctype declaration (what this line does) or disable external entities (what the following two lines do). I'm not sure it's problematic to do both though, so maybe we should keep it.

https://blog.compass-security.com/2012/08/secure-xml-parser-configuration/

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@labkey-jeckels labkey-jeckels Feb 16, 2026

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Yes, should be safe to do both, just in case.

factory.setFeature("http://xml.org/sax/features/external-general-entities", false);
factory.setFeature("http://xml.org/sax/features/external-parameter-entities", false);
factory.setFeature(XMLConstants.FEATURE_SECURE_PROCESSING, true);

SAXParser parser = factory.newSAXParser();
parser.parse(is, new DefaultHandler()
{
final ArrayList<String> elementStack = new ArrayList<>();
Expand Down