bpo-31758: Prevent crashes when using an uninitialized _elementtree.XMLParser object (GH-3997) (GH-19485)
(cherry picked from commit 402e1cdb132f384e4dcde7a3d7ec7ea1fc7ab527)
diff --git a/Lib/test/test_xml_etree_c.py b/Lib/test/test_xml_etree_c.py
index 2144d20..e26e171 100644
--- a/Lib/test/test_xml_etree_c.py
+++ b/Lib/test/test_xml_etree_c.py
@@ -118,6 +118,21 @@
elem.tail = X()
elem.__setstate__({'tag': 42}) # shouldn't cause an assertion failure
+ @support.cpython_only
+ def test_uninitialized_parser(self):
+ # The interpreter shouldn't crash in case of calling methods or
+ # accessing attributes of uninitialized XMLParser objects.
+ parser = cET.XMLParser.__new__(cET.XMLParser)
+ self.assertRaises(ValueError, parser.close)
+ self.assertRaises(ValueError, parser.feed, 'foo')
+ class MockFile:
+ def read(*args):
+ return ''
+ self.assertRaises(ValueError, parser._parse_whole, MockFile())
+ self.assertRaises(ValueError, parser._setevents, None)
+ self.assertIsNone(parser.entity)
+ self.assertIsNone(parser.target)
+
def test_setstate_leaks(self):
# Test reference leaks
elem = cET.Element.__new__(cET.Element)
diff --git a/Misc/NEWS.d/next/Library/2017-10-14-21-02-40.bpo-31758.563ZZb.rst b/Misc/NEWS.d/next/Library/2017-10-14-21-02-40.bpo-31758.563ZZb.rst
new file mode 100644
index 0000000..92e55db
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2017-10-14-21-02-40.bpo-31758.563ZZb.rst
@@ -0,0 +1,2 @@
+Prevent crashes when using an uninitialized ``_elementtree.XMLParser``
+object. Patch by Oren Milman.
diff --git a/Modules/_elementtree.c b/Modules/_elementtree.c
index 776b86c..a96e3f4 100644
--- a/Modules/_elementtree.c
+++ b/Modules/_elementtree.c
@@ -3877,6 +3877,17 @@
Py_TYPE(self)->tp_free((PyObject *)self);
}
+Py_LOCAL_INLINE(int)
+_check_xmlparser(XMLParserObject* self)
+{
+ if (self->target == NULL) {
+ PyErr_SetString(PyExc_ValueError,
+ "XMLParser.__init__() wasn't called");
+ return 0;
+ }
+ return 1;
+}
+
LOCAL(PyObject*)
expat_parse(XMLParserObject* self, const char* data, int data_len, int final)
{
@@ -3913,6 +3924,10 @@
/* end feeding data to parser */
PyObject* res;
+
+ if (!_check_xmlparser(self)) {
+ return NULL;
+ }
res = expat_parse(self, "", 0, 1);
if (!res)
return NULL;
@@ -3944,6 +3959,9 @@
{
/* feed data to parser */
+ if (!_check_xmlparser(self)) {
+ return NULL;
+ }
if (PyUnicode_Check(data)) {
Py_ssize_t data_len;
const char *data_ptr = PyUnicode_AsUTF8AndSize(data, &data_len);
@@ -3991,6 +4009,9 @@
PyObject* temp;
PyObject* res;
+ if (!_check_xmlparser(self)) {
+ return NULL;
+ }
reader = PyObject_GetAttrString(file, "read");
if (!reader)
return NULL;
@@ -4078,6 +4099,9 @@
TreeBuilderObject *target;
PyObject *events_append, *events_seq;
+ if (!_check_xmlparser(self)) {
+ return NULL;
+ }
if (!TreeBuilder_CheckExact(self->target)) {
PyErr_SetString(
PyExc_TypeError,