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00422: pythongh-115133: Fix tests for XMLPullParser with Expat 2.6.0
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Feeding the parser by too small chunks defers parsing to prevent
CVE-2023-52425. Future versions of Expat may be more reactive.

(cherry picked from commit 4a08e7b)
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serhiy-storchaka authored and stratakis committed Mar 11, 2024
1 parent 412dac1 commit fd2942b
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58 changes: 36 additions & 22 deletions Lib/test/test_xml_etree.py
Original file line number Diff line number Diff line change
Expand Up @@ -10,6 +10,7 @@
import io
import operator
import pickle
import pyexpat
import sys
import types
import unittest
Expand Down Expand Up @@ -97,6 +98,10 @@
<document>&entity;</document>
"""

fails_with_expat_2_6_0 = (unittest.expectedFailure
if pyexpat.version_info >= (2, 6, 0) else
lambda test: test)

class ModuleTest(unittest.TestCase):
def test_sanity(self):
# Import sanity.
Expand Down Expand Up @@ -1044,28 +1049,37 @@ def assert_event_tags(self, parser, expected):
self.assertEqual([(action, elem.tag) for action, elem in events],
expected)

def test_simple_xml(self):
for chunk_size in (None, 1, 5):
with self.subTest(chunk_size=chunk_size):
parser = ET.XMLPullParser()
self.assert_event_tags(parser, [])
self._feed(parser, "<!-- comment -->\n", chunk_size)
self.assert_event_tags(parser, [])
self._feed(parser,
"<root>\n <element key='value'>text</element",
chunk_size)
self.assert_event_tags(parser, [])
self._feed(parser, ">\n", chunk_size)
self.assert_event_tags(parser, [('end', 'element')])
self._feed(parser, "<element>text</element>tail\n", chunk_size)
self._feed(parser, "<empty-element/>\n", chunk_size)
self.assert_event_tags(parser, [
('end', 'element'),
('end', 'empty-element'),
])
self._feed(parser, "</root>\n", chunk_size)
self.assert_event_tags(parser, [('end', 'root')])
self.assertIsNone(parser.close())
def test_simple_xml(self, chunk_size=None):
parser = ET.XMLPullParser()
self.assert_event_tags(parser, [])
self._feed(parser, "<!-- comment -->\n", chunk_size)
self.assert_event_tags(parser, [])
self._feed(parser,
"<root>\n <element key='value'>text</element",
chunk_size)
self.assert_event_tags(parser, [])
self._feed(parser, ">\n", chunk_size)
self.assert_event_tags(parser, [('end', 'element')])
self._feed(parser, "<element>text</element>tail\n", chunk_size)
self._feed(parser, "<empty-element/>\n", chunk_size)
self.assert_event_tags(parser, [
('end', 'element'),
('end', 'empty-element'),
])
self._feed(parser, "</root>\n", chunk_size)
self.assert_event_tags(parser, [('end', 'root')])
self.assertIsNone(parser.close())

@fails_with_expat_2_6_0
def test_simple_xml_chunk_1(self):
self.test_simple_xml(chunk_size=1)

@fails_with_expat_2_6_0
def test_simple_xml_chunk_5(self):
self.test_simple_xml(chunk_size=5)

def test_simple_xml_chunk_22(self):
self.test_simple_xml(chunk_size=22)

def test_feed_while_iterating(self):
parser = ET.XMLPullParser()
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@@ -0,0 +1,2 @@
Fix tests for :class:`~xml.etree.ElementTree.XMLPullParser` with Expat
2.6.0.

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