#3664: The pickle module could segfault if a Pickler instance is not correctly initialized:
when a subclass forgets to call the base __init__ method,
or when __init__ is called a second time with invalid parameters
Patch by Alexandre Vassalotti.
diff --git a/Lib/test/pickletester.py b/Lib/test/pickletester.py
index a622145..4c301ad 100644
--- a/Lib/test/pickletester.py
+++ b/Lib/test/pickletester.py
@@ -996,6 +996,20 @@
pickle.Pickler(f, -1)
pickle.Pickler(f, protocol=-1)
+ def test_bad_init(self):
+ # Test issue3664 (pickle can segfault from a badly initialized Pickler).
+ from io import BytesIO
+ # Override initialization without calling __init__() of the superclass.
+ class BadPickler(pickle.Pickler):
+ def __init__(self): pass
+
+ class BadUnpickler(pickle.Unpickler):
+ def __init__(self): pass
+
+ self.assertRaises(pickle.PicklingError, BadPickler().dump, 0)
+ self.assertRaises(pickle.UnpicklingError, BadUnpickler().load)
+
+
class AbstractPersistentPicklerTests(unittest.TestCase):
# This class defines persistent_id() and persistent_load()
diff --git a/Misc/NEWS b/Misc/NEWS
index 8781877..a9adda9 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -33,7 +33,10 @@
Library
-------
-- telnetlib now works completely in bytes.
+- Issue #3664: The pickle module could segfault if a subclass of Pickler fails
+ to call the base __init__ method.
+
+- Issue #3725: telnetlib now works completely in bytes.
- Issue #4072: Restore build_py_2to3.
diff --git a/Modules/_pickle.c b/Modules/_pickle.c
index 91ebe2e..2b672a7 100644
--- a/Modules/_pickle.c
+++ b/Modules/_pickle.c
@@ -421,6 +421,11 @@
{
PyObject *data, *result;
+ if (self->write_buf == NULL) {
+ PyErr_SetString(PyExc_SystemError, "invalid write buffer");
+ return -1;
+ }
+
if (s == NULL) {
if (!(self->buf_size))
return 0;
@@ -2378,6 +2383,16 @@
{
PyObject *obj;
+ /* Check whether the Pickler was initialized correctly (issue3664).
+ Developers often forget to call __init__() in their subclasses, which
+ would trigger a segfault without this check. */
+ if (self->write == NULL) {
+ PyErr_Format(PicklingError,
+ "Pickler.__init__() was not called by %s.__init__()",
+ Py_TYPE(self)->tp_name);
+ return NULL;
+ }
+
if (!PyArg_ParseTuple(args, "O:dump", &obj))
return NULL;