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gh-132097: fix runtime UB when calling expat handlers #132265

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merged 1 commit into from
Apr 12, 2025
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gh-132097: fix runtime UB when calling expat handlers #132265

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83 changes: 45 additions & 38 deletions Modules/_elementtree.c
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Original file line number Diff line number Diff line change
Expand Up @@ -3082,8 +3082,7 @@ typedef struct {
PyObject *elementtree_module;
} XMLParserObject;


#define _XMLParser_CAST(op) ((XMLParserObject *)(op))
#define XMLParserObject_CAST(op) ((XMLParserObject *)(op))

/* helpers */

Expand Down Expand Up @@ -3207,12 +3206,12 @@ expat_set_error(elementtreestate *st, enum XML_Error error_code,
/* handlers */

static void
expat_default_handler(XMLParserObject* self, const XML_Char* data_in,
int data_len)
expat_default_handler(void *op, const XML_Char *data_in, int data_len)
{
PyObject* key;
PyObject* value;
PyObject* res;
XMLParserObject *self = XMLParserObject_CAST(op);
PyObject *key;
PyObject *value;
PyObject *res;

if (data_len < 2 || data_in[0] != '&')
return;
Expand Down Expand Up @@ -3254,12 +3253,13 @@ expat_default_handler(XMLParserObject* self, const XML_Char* data_in,
}

static void
expat_start_handler(XMLParserObject* self, const XML_Char* tag_in,
expat_start_handler(void *op, const XML_Char *tag_in,
const XML_Char **attrib_in)
{
PyObject* res;
PyObject* tag;
PyObject* attrib;
XMLParserObject *self = XMLParserObject_CAST(op);
PyObject *res;
PyObject *tag;
PyObject *attrib;
int ok;

if (PyErr_Occurred())
Expand All @@ -3278,13 +3278,13 @@ expat_start_handler(XMLParserObject* self, const XML_Char* tag_in,
return;
}
while (attrib_in[0] && attrib_in[1]) {
PyObject* key = makeuniversal(self, attrib_in[0]);
PyObject *key = makeuniversal(self, attrib_in[0]);
if (key == NULL) {
Py_DECREF(attrib);
Py_DECREF(tag);
return;
}
PyObject* value = PyUnicode_DecodeUTF8(attrib_in[1], strlen(attrib_in[1]), "strict");
PyObject *value = PyUnicode_DecodeUTF8(attrib_in[1], strlen(attrib_in[1]), "strict");
if (value == NULL) {
Py_DECREF(key);
Py_DECREF(attrib);
Expand Down Expand Up @@ -3331,11 +3331,12 @@ expat_start_handler(XMLParserObject* self, const XML_Char* tag_in,
}

static void
expat_data_handler(XMLParserObject* self, const XML_Char* data_in,
expat_data_handler(void *op, const XML_Char *data_in,
int data_len)
{
PyObject* data;
PyObject* res;
XMLParserObject *self = XMLParserObject_CAST(op);
PyObject *data;
PyObject *res;

if (PyErr_Occurred())
return;
Expand All @@ -3359,10 +3360,11 @@ expat_data_handler(XMLParserObject* self, const XML_Char* data_in,
}

static void
expat_end_handler(XMLParserObject* self, const XML_Char* tag_in)
expat_end_handler(void *op, const XML_Char *tag_in)
{
PyObject* tag;
PyObject* res = NULL;
XMLParserObject *self = XMLParserObject_CAST(op);
PyObject *tag;
PyObject *res = NULL;

if (PyErr_Occurred())
return;
Expand All @@ -3386,12 +3388,13 @@ expat_end_handler(XMLParserObject* self, const XML_Char* tag_in)
}

static void
expat_start_ns_handler(XMLParserObject* self, const XML_Char* prefix_in,
expat_start_ns_handler(void *op, const XML_Char *prefix_in,
const XML_Char *uri_in)
{
PyObject* res = NULL;
PyObject* uri;
PyObject* prefix;
XMLParserObject *self = XMLParserObject_CAST(op);
PyObject *res = NULL;
PyObject *uri;
PyObject *prefix;

if (PyErr_Occurred())
return;
Expand Down Expand Up @@ -3430,7 +3433,7 @@ expat_start_ns_handler(XMLParserObject* self, const XML_Char* prefix_in,
return;
}

PyObject* args[2] = {prefix, uri};
PyObject *args[2] = {prefix, uri};
res = PyObject_Vectorcall(self->handle_start_ns, args, 2, NULL);
Py_DECREF(uri);
Py_DECREF(prefix);
Expand All @@ -3440,10 +3443,11 @@ expat_start_ns_handler(XMLParserObject* self, const XML_Char* prefix_in,
}

static void
expat_end_ns_handler(XMLParserObject* self, const XML_Char* prefix_in)
expat_end_ns_handler(void *op, const XML_Char *prefix_in)
{
XMLParserObject *self = XMLParserObject_CAST(op);
PyObject *res = NULL;
PyObject* prefix;
PyObject *prefix;

if (PyErr_Occurred())
return;
Expand Down Expand Up @@ -3472,10 +3476,11 @@ expat_end_ns_handler(XMLParserObject* self, const XML_Char* prefix_in)
}

static void
expat_comment_handler(XMLParserObject* self, const XML_Char* comment_in)
expat_comment_handler(void *op, const XML_Char *comment_in)
{
PyObject* comment;
PyObject* res;
XMLParserObject *self = XMLParserObject_CAST(op);
PyObject *comment;
PyObject *res;

if (PyErr_Occurred())
return;
Expand Down Expand Up @@ -3504,12 +3509,13 @@ expat_comment_handler(XMLParserObject* self, const XML_Char* comment_in)
}

static void
expat_start_doctype_handler(XMLParserObject *self,
expat_start_doctype_handler(void *op,
const XML_Char *doctype_name,
const XML_Char *sysid,
const XML_Char *pubid,
int has_internal_subset)
{
XMLParserObject *self = XMLParserObject_CAST(op);
PyObject *doctype_name_obj, *sysid_obj, *pubid_obj;
PyObject *res;

Expand Down Expand Up @@ -3562,12 +3568,13 @@ expat_start_doctype_handler(XMLParserObject *self,
}

static void
expat_pi_handler(XMLParserObject* self, const XML_Char* target_in,
const XML_Char* data_in)
expat_pi_handler(void *op, const XML_Char *target_in,
const XML_Char *data_in)
{
PyObject* pi_target;
PyObject* data;
PyObject* res;
XMLParserObject *self = XMLParserObject_CAST(op);
PyObject *pi_target;
PyObject *data;
PyObject *res;

if (PyErr_Occurred())
return;
Expand Down Expand Up @@ -3597,7 +3604,7 @@ expat_pi_handler(XMLParserObject* self, const XML_Char* target_in,
if (!data)
goto error;

PyObject* args[2] = {pi_target, data};
PyObject *args[2] = {pi_target, data};
res = PyObject_Vectorcall(self->handle_pi, args, 2, NULL);
Py_XDECREF(res);
Py_DECREF(data);
Expand Down Expand Up @@ -3777,7 +3784,7 @@ _elementtree_XMLParser___init___impl(XMLParserObject *self, PyObject *target,
static int
xmlparser_gc_traverse(PyObject *op, visitproc visit, void *arg)
{
XMLParserObject *self = _XMLParser_CAST(op);
XMLParserObject *self = XMLParserObject_CAST(op);
Py_VISIT(Py_TYPE(self));
Py_VISIT(self->handle_close);
Py_VISIT(self->handle_pi);
Expand All @@ -3799,7 +3806,7 @@ xmlparser_gc_traverse(PyObject *op, visitproc visit, void *arg)
static int
xmlparser_gc_clear(PyObject *op)
{
XMLParserObject *self = _XMLParser_CAST(op);
XMLParserObject *self = XMLParserObject_CAST(op);
elementtreestate *st = self->state;
if (self->parser != NULL) {
XML_Parser parser = self->parser;
Expand Down
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