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| author | Miss Skeleton (bot) <31488909+miss-islington@users.noreply.github.com> | 2020-10-20 02:35:23 (GMT) |
|---|---|---|
| committer | GitHub <noreply@github.com> | 2020-10-20 02:35:23 (GMT) |
| commit | 65894cac0835cb8f469f649e20aa1be8bf89f5ae (patch) | |
| tree | 38c0457e2fb026f38468a5fe3024630108907a7b | |
| parent | 3faef630a44be2d1ea5516e85e95fef4fd027a95 (diff) | |
| download | cpython-65894cac0835cb8f469f649e20aa1be8bf89f5ae.zip cpython-65894cac0835cb8f469f649e20aa1be8bf89f5ae.tar.gz cpython-65894cac0835cb8f469f649e20aa1be8bf89f5ae.tar.bz2 | |
bpo-42051: Reject XML entity declarations in plist files (GH-22760)
(cherry picked from commit 05ee790f4d1cd8725a90b54268fc1dfe5b4d1fa2)
Co-authored-by: Ronald Oussoren <ronaldoussoren@mac.com>
| -rw-r--r-- | Lib/plistlib.py | 7 | ||||
| -rw-r--r-- | Lib/test/test_plistlib.py | 18 | ||||
| -rw-r--r-- | Misc/NEWS.d/next/Security/2020-10-19-10-56-27.bpo-42051.EU_B7u.rst | 3 |
3 files changed, 28 insertions, 0 deletions
diff --git a/Lib/plistlib.py b/Lib/plistlib.py index 04f8a87..533ed13 100644 --- a/Lib/plistlib.py +++ b/Lib/plistlib.py @@ -285,9 +285,16 @@ 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) diff --git a/Lib/test/test_plistlib.py b/Lib/test/test_plistlib.py index 0d887e2..de1c848 100644 --- a/Lib/test/test_plistlib.py +++ b/Lib/test/test_plistlib.py @@ -105,6 +105,19 @@ TESTDATA={ AAABOQ=='''), } +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): @@ -525,6 +538,11 @@ class TestPlistlib(unittest.TestCase): with self.assertRaises(OverflowError): plistlib.dumps(huge_uid, fmt=plistlib.FMT_BINARY) + 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): diff --git a/Misc/NEWS.d/next/Security/2020-10-19-10-56-27.bpo-42051.EU_B7u.rst b/Misc/NEWS.d/next/Security/2020-10-19-10-56-27.bpo-42051.EU_B7u.rst new file mode 100644 index 0000000..e865ed1 --- /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. |