File CVE-2022-48565-plistlib-XML-vulns.patch of Package python3.42323
From 4d8f9e2e4461de92bd1e0c92ed433480d761670f Mon Sep 17 00:00:00 2001
From: Ned Deily <nad@python.org>
Date: Mon, 19 Oct 2020 22:36:27 -0400
Subject: [PATCH] bpo-42051: Reject XML entity declarations in plist files
(GH-22760) (GH-22801)
Co-authored-by: Ronald Oussoren <ronaldoussoren@mac.com>
(cherry picked from commit e512bc799e3864fe3b1351757261762d63471efc)
Co-authored-by: Ned Deily <nad@python.org>
---
Lib/plistlib.py | 7 +++
Lib/test/test_plistlib.py | 18 ++++++++++
Misc/NEWS.d/next/Security/2020-10-19-10-56-27.bpo-42051.EU_B7u.rst | 3 +
3 files changed, 28 insertions(+)
create mode 100644 Misc/NEWS.d/next/Security/2020-10-19-10-56-27.bpo-42051.EU_B7u.rst
--- a/Lib/plistlib.py
+++ b/Lib/plistlib.py
@@ -322,9 +322,16 @@ class _PlistParser:
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)
--- a/Lib/test/test_plistlib.py
+++ b/Lib/test/test_plistlib.py
@@ -374,6 +374,19 @@ INVALID_BINARY_PLISTS = [
),
]
+XML_PLIST_WITH_ENTITY=b'''\
+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd" [
+ <!ENTITY entity "replacement text">
+ ]>
+<plist version="1.0">
+ <dict>
+ <key>A</key>
+ <string>&entity;</string>
+ </dict>
+</plist>
+'''
+
class TestPlistlib(unittest.TestCase):
@@ -711,6 +724,11 @@ class TestPlistlib(unittest.TestCase):
pl2 = plistlib.loads(data)
self.assertEqual(dict(pl), dict(pl2))
+ def test_xml_plist_with_entity_decl(self):
+ with self.assertRaisesRegex(plistlib.InvalidFileException,
+ "XML entity declarations are not supported"):
+ plistlib.loads(XML_PLIST_WITH_ENTITY, fmt=plistlib.FMT_XML)
+
class TestBinaryPlistlib(unittest.TestCase):
--- /dev/null
+++ b/Misc/NEWS.d/next/Security/2020-10-19-10-56-27.bpo-42051.EU_B7u.rst
@@ -0,0 +1,3 @@
+The :mod:`plistlib` module no longer accepts entity declarations in XML
+plist files to avoid XML vulnerabilities. This should not affect users as
+entity declarations are not used in regular plist files.
