bpo-42051: Reject XML entity declarations in plist files (GH-22760)
(cherry picked from commit 05ee790f4d1cd8725a90b54268fc1dfe5b4d1fa2)
Co-authored-by: Ronald Oussoren <ronaldoussoren@mac.com>
diff --git a/Lib/plistlib.py b/Lib/plistlib.py
index aff5fe3..ba7ac19 100644
--- a/Lib/plistlib.py
+++ b/Lib/plistlib.py
@@ -173,9 +173,16 @@
self.parser.StartElementHandler = self.handle_begin_element
self.parser.EndElementHandler = self.handle_end_element
self.parser.CharacterDataHandler = self.handle_data
+ self.parser.EntityDeclHandler = self.handle_entity_decl
self.parser.ParseFile(fileobj)
return self.root
+ def handle_entity_decl(self, entity_name, is_parameter_entity, value, base, system_id, public_id, notation_name):
+ # Reject plist files with entity declarations to avoid XML vulnerabilies in expat.
+ # Regular plist files don't contain those declerations, and Apple's plutil tool does not
+ # accept them either.
+ raise InvalidFileException("XML entity declarations are not supported in plist files")
+
def handle_begin_element(self, element, attrs):
self.data = []
handler = getattr(self, "begin_" + element, None)