cpython/Lib/test/test_pulldom.py
Christian Heimes 17b1d5d4e3 bpo-17239: Disable external entities in SAX parser (GH-9217)
The SAX parser no longer processes general external entities by default
to increase security. Before, the parser created network connections
to fetch remote files or loaded local files from the file system for DTD
and entities.

Signed-off-by: Christian Heimes <christian@python.org>



https://bugs.python.org/issue17239
2018-09-23 00:50:25 -07:00

357 lines
13 KiB
Python

import io
import unittest
import xml.sax
from xml.sax.xmlreader import AttributesImpl
from xml.sax.handler import feature_external_ges
from xml.dom import pulldom
from test.support import findfile
tstfile = findfile("test.xml", subdir="xmltestdata")
# A handy XML snippet, containing attributes, a namespace prefix, and a
# self-closing tag:
SMALL_SAMPLE = """<?xml version="1.0"?>
<html xmlns="http://www.w3.org/1999/xhtml" xmlns:xdc="http://www.xml.com/books">
<!-- A comment -->
<title>Introduction to XSL</title>
<hr/>
<p><xdc:author xdc:attrib="prefixed attribute" attrib="other attrib">A. Namespace</xdc:author></p>
</html>"""
class PullDOMTestCase(unittest.TestCase):
def test_parse(self):
"""Minimal test of DOMEventStream.parse()"""
# This just tests that parsing from a stream works. Actual parser
# semantics are tested using parseString with a more focused XML
# fragment.
# Test with a filename:
handler = pulldom.parse(tstfile)
self.addCleanup(handler.stream.close)
list(handler)
# Test with a file object:
with open(tstfile, "rb") as fin:
list(pulldom.parse(fin))
def test_parse_semantics(self):
"""Test DOMEventStream parsing semantics."""
items = pulldom.parseString(SMALL_SAMPLE)
evt, node = next(items)
# Just check the node is a Document:
self.assertTrue(hasattr(node, "createElement"))
self.assertEqual(pulldom.START_DOCUMENT, evt)
evt, node = next(items)
self.assertEqual(pulldom.START_ELEMENT, evt)
self.assertEqual("html", node.tagName)
self.assertEqual(2, len(node.attributes))
self.assertEqual(node.attributes.getNamedItem("xmlns:xdc").value,
"http://www.xml.com/books")
evt, node = next(items)
self.assertEqual(pulldom.CHARACTERS, evt) # Line break
evt, node = next(items)
# XXX - A comment should be reported here!
# self.assertEqual(pulldom.COMMENT, evt)
# Line break after swallowed comment:
self.assertEqual(pulldom.CHARACTERS, evt)
evt, node = next(items)
self.assertEqual("title", node.tagName)
title_node = node
evt, node = next(items)
self.assertEqual(pulldom.CHARACTERS, evt)
self.assertEqual("Introduction to XSL", node.data)
evt, node = next(items)
self.assertEqual(pulldom.END_ELEMENT, evt)
self.assertEqual("title", node.tagName)
self.assertTrue(title_node is node)
evt, node = next(items)
self.assertEqual(pulldom.CHARACTERS, evt)
evt, node = next(items)
self.assertEqual(pulldom.START_ELEMENT, evt)
self.assertEqual("hr", node.tagName)
evt, node = next(items)
self.assertEqual(pulldom.END_ELEMENT, evt)
self.assertEqual("hr", node.tagName)
evt, node = next(items)
self.assertEqual(pulldom.CHARACTERS, evt)
evt, node = next(items)
self.assertEqual(pulldom.START_ELEMENT, evt)
self.assertEqual("p", node.tagName)
evt, node = next(items)
self.assertEqual(pulldom.START_ELEMENT, evt)
self.assertEqual("xdc:author", node.tagName)
evt, node = next(items)
self.assertEqual(pulldom.CHARACTERS, evt)
evt, node = next(items)
self.assertEqual(pulldom.END_ELEMENT, evt)
self.assertEqual("xdc:author", node.tagName)
evt, node = next(items)
self.assertEqual(pulldom.END_ELEMENT, evt)
evt, node = next(items)
self.assertEqual(pulldom.CHARACTERS, evt)
evt, node = next(items)
self.assertEqual(pulldom.END_ELEMENT, evt)
# XXX No END_DOCUMENT item is ever obtained:
#evt, node = next(items)
#self.assertEqual(pulldom.END_DOCUMENT, evt)
def test_expandItem(self):
"""Ensure expandItem works as expected."""
items = pulldom.parseString(SMALL_SAMPLE)
# Loop through the nodes until we get to a "title" start tag:
for evt, item in items:
if evt == pulldom.START_ELEMENT and item.tagName == "title":
items.expandNode(item)
self.assertEqual(1, len(item.childNodes))
break
else:
self.fail("No \"title\" element detected in SMALL_SAMPLE!")
# Loop until we get to the next start-element:
for evt, node in items:
if evt == pulldom.START_ELEMENT:
break
self.assertEqual("hr", node.tagName,
"expandNode did not leave DOMEventStream in the correct state.")
# Attempt to expand a standalone element:
items.expandNode(node)
self.assertEqual(next(items)[0], pulldom.CHARACTERS)
evt, node = next(items)
self.assertEqual(node.tagName, "p")
items.expandNode(node)
next(items) # Skip character data
evt, node = next(items)
self.assertEqual(node.tagName, "html")
with self.assertRaises(StopIteration):
next(items)
items.clear()
self.assertIsNone(items.parser)
self.assertIsNone(items.stream)
@unittest.expectedFailure
def test_comment(self):
"""PullDOM does not receive "comment" events."""
items = pulldom.parseString(SMALL_SAMPLE)
for evt, _ in items:
if evt == pulldom.COMMENT:
break
else:
self.fail("No comment was encountered")
@unittest.expectedFailure
def test_end_document(self):
"""PullDOM does not receive "end-document" events."""
items = pulldom.parseString(SMALL_SAMPLE)
# Read all of the nodes up to and including </html>:
for evt, node in items:
if evt == pulldom.END_ELEMENT and node.tagName == "html":
break
try:
# Assert that the next node is END_DOCUMENT:
evt, node = next(items)
self.assertEqual(pulldom.END_DOCUMENT, evt)
except StopIteration:
self.fail(
"Ran out of events, but should have received END_DOCUMENT")
def test_getitem_deprecation(self):
parser = pulldom.parseString(SMALL_SAMPLE)
with self.assertWarnsRegex(DeprecationWarning,
r'Use iterator protocol instead'):
# This should have returned 'END_ELEMENT'.
self.assertEqual(parser[-1][0], pulldom.START_DOCUMENT)
def test_external_ges_default(self):
parser = pulldom.parseString(SMALL_SAMPLE)
saxparser = parser.parser
ges = saxparser.getFeature(feature_external_ges)
self.assertEqual(ges, False)
class ThoroughTestCase(unittest.TestCase):
"""Test the hard-to-reach parts of pulldom."""
def test_thorough_parse(self):
"""Test some of the hard-to-reach parts of PullDOM."""
self._test_thorough(pulldom.parse(None, parser=SAXExerciser()))
@unittest.expectedFailure
def test_sax2dom_fail(self):
"""SAX2DOM can"t handle a PI before the root element."""
pd = SAX2DOMTestHelper(None, SAXExerciser(), 12)
self._test_thorough(pd)
def test_thorough_sax2dom(self):
"""Test some of the hard-to-reach parts of SAX2DOM."""
pd = SAX2DOMTestHelper(None, SAX2DOMExerciser(), 12)
self._test_thorough(pd, False)
def _test_thorough(self, pd, before_root=True):
"""Test some of the hard-to-reach parts of the parser, using a mock
parser."""
evt, node = next(pd)
self.assertEqual(pulldom.START_DOCUMENT, evt)
# Just check the node is a Document:
self.assertTrue(hasattr(node, "createElement"))
if before_root:
evt, node = next(pd)
self.assertEqual(pulldom.COMMENT, evt)
self.assertEqual("a comment", node.data)
evt, node = next(pd)
self.assertEqual(pulldom.PROCESSING_INSTRUCTION, evt)
self.assertEqual("target", node.target)
self.assertEqual("data", node.data)
evt, node = next(pd)
self.assertEqual(pulldom.START_ELEMENT, evt)
self.assertEqual("html", node.tagName)
evt, node = next(pd)
self.assertEqual(pulldom.COMMENT, evt)
self.assertEqual("a comment", node.data)
evt, node = next(pd)
self.assertEqual(pulldom.PROCESSING_INSTRUCTION, evt)
self.assertEqual("target", node.target)
self.assertEqual("data", node.data)
evt, node = next(pd)
self.assertEqual(pulldom.START_ELEMENT, evt)
self.assertEqual("p", node.tagName)
evt, node = next(pd)
self.assertEqual(pulldom.CHARACTERS, evt)
self.assertEqual("text", node.data)
evt, node = next(pd)
self.assertEqual(pulldom.END_ELEMENT, evt)
self.assertEqual("p", node.tagName)
evt, node = next(pd)
self.assertEqual(pulldom.END_ELEMENT, evt)
self.assertEqual("html", node.tagName)
evt, node = next(pd)
self.assertEqual(pulldom.END_DOCUMENT, evt)
class SAXExerciser(object):
"""A fake sax parser that calls some of the harder-to-reach sax methods to
ensure it emits the correct events"""
def setContentHandler(self, handler):
self._handler = handler
def parse(self, _):
h = self._handler
h.startDocument()
# The next two items ensure that items preceding the first
# start_element are properly stored and emitted:
h.comment("a comment")
h.processingInstruction("target", "data")
h.startElement("html", AttributesImpl({}))
h.comment("a comment")
h.processingInstruction("target", "data")
h.startElement("p", AttributesImpl({"class": "paraclass"}))
h.characters("text")
h.endElement("p")
h.endElement("html")
h.endDocument()
def stub(self, *args, **kwargs):
"""Stub method. Does nothing."""
pass
setProperty = stub
setFeature = stub
class SAX2DOMExerciser(SAXExerciser):
"""The same as SAXExerciser, but without the processing instruction and
comment before the root element, because S2D can"t handle it"""
def parse(self, _):
h = self._handler
h.startDocument()
h.startElement("html", AttributesImpl({}))
h.comment("a comment")
h.processingInstruction("target", "data")
h.startElement("p", AttributesImpl({"class": "paraclass"}))
h.characters("text")
h.endElement("p")
h.endElement("html")
h.endDocument()
class SAX2DOMTestHelper(pulldom.DOMEventStream):
"""Allows us to drive SAX2DOM from a DOMEventStream."""
def reset(self):
self.pulldom = pulldom.SAX2DOM()
# This content handler relies on namespace support
self.parser.setFeature(xml.sax.handler.feature_namespaces, 1)
self.parser.setContentHandler(self.pulldom)
class SAX2DOMTestCase(unittest.TestCase):
def confirm(self, test, testname="Test"):
self.assertTrue(test, testname)
def test_basic(self):
"""Ensure SAX2DOM can parse from a stream."""
with io.StringIO(SMALL_SAMPLE) as fin:
sd = SAX2DOMTestHelper(fin, xml.sax.make_parser(),
len(SMALL_SAMPLE))
for evt, node in sd:
if evt == pulldom.START_ELEMENT and node.tagName == "html":
break
# Because the buffer is the same length as the XML, all the
# nodes should have been parsed and added:
self.assertGreater(len(node.childNodes), 0)
def testSAX2DOM(self):
"""Ensure SAX2DOM expands nodes as expected."""
sax2dom = pulldom.SAX2DOM()
sax2dom.startDocument()
sax2dom.startElement("doc", {})
sax2dom.characters("text")
sax2dom.startElement("subelm", {})
sax2dom.characters("text")
sax2dom.endElement("subelm")
sax2dom.characters("text")
sax2dom.endElement("doc")
sax2dom.endDocument()
doc = sax2dom.document
root = doc.documentElement
(text1, elm1, text2) = root.childNodes
text3 = elm1.childNodes[0]
self.assertIsNone(text1.previousSibling)
self.assertIs(text1.nextSibling, elm1)
self.assertIs(elm1.previousSibling, text1)
self.assertIs(elm1.nextSibling, text2)
self.assertIs(text2.previousSibling, elm1)
self.assertIsNone(text2.nextSibling)
self.assertIsNone(text3.previousSibling)
self.assertIsNone(text3.nextSibling)
self.assertIs(root.parentNode, doc)
self.assertIs(text1.parentNode, root)
self.assertIs(elm1.parentNode, root)
self.assertIs(text2.parentNode, root)
self.assertIs(text3.parentNode, elm1)
doc.unlink()
if __name__ == "__main__":
unittest.main()