Issue #27330: Fixed possible leaks in the ctypes module.

Misc/NEWS

@@ -10,6 +10,8 @@ What's New in Python 3.6.0 alpha 3
 Library
 -------
 
+- Issue #27330: Fixed possible leaks in the ctypes module.
+
 - Issue #27238: Got rid of bare excepts in the turtle module.  Original patch
   by Jelle Zijlstra.
 

Modules/_ctypes/_ctypes.c

@@ -1252,8 +1252,10 @@ add_methods(PyTypeObject *type, PyMethodDef *meth)
         descr = PyDescr_NewMethod(type, meth);
         if (descr == NULL)
             return -1;
-        if (PyDict_SetItemString(dict,meth->ml_name, descr) < 0)
+        if (PyDict_SetItemString(dict, meth->ml_name, descr) < 0) {
+            Py_DECREF(descr);
             return -1;
+        }
         Py_DECREF(descr);
     }
     return 0;
@@ -1268,8 +1270,10 @@ add_members(PyTypeObject *type, PyMemberDef *memb)
         descr = PyDescr_NewMember(type, memb);
         if (descr == NULL)
             return -1;
-        if (PyDict_SetItemString(dict, memb->name, descr) < 0)
+        if (PyDict_SetItemString(dict, memb->name, descr) < 0) {
+            Py_DECREF(descr);
             return -1;
+        }
         Py_DECREF(descr);
     }
     return 0;
@@ -1285,8 +1289,10 @@ add_getset(PyTypeObject *type, PyGetSetDef *gsp)
         descr = PyDescr_NewGetSet(type, gsp);
         if (descr == NULL)
             return -1;
-        if (PyDict_SetItemString(dict, gsp->name, descr) < 0)
+        if (PyDict_SetItemString(dict, gsp->name, descr) < 0) {
+            Py_DECREF(descr);
             return -1;
+        }
         Py_DECREF(descr);
     }
     return 0;
@@ -1778,6 +1784,7 @@ static PyObject *CreateSwappedType(PyTypeObject *type, PyObject *args, PyObject
 
     newname = PyUnicode_Concat(name, suffix);
     if (newname == NULL) {
+        Py_DECREF(swapped_args);
         return NULL;
     }
 
@@ -1797,8 +1804,10 @@ static PyObject *CreateSwappedType(PyTypeObject *type, PyObject *args, PyObject
 
     stgdict = (StgDictObject *)PyObject_CallObject(
         (PyObject *)&PyCStgDict_Type, NULL);
-    if (!stgdict) /* XXX leaks result! */
+    if (!stgdict) {
+        Py_DECREF(result);
         return NULL;
+    }
 
     stgdict->ffi_type_pointer = *fmt->pffi_type;
     stgdict->align = fmt->pffi_type->alignment;
@@ -1978,8 +1987,10 @@ PyCSimpleType_new(PyTypeObject *type, PyObject *args, PyObject *kwds)
             PyObject *meth;
             int x;
             meth = PyDescr_NewClassMethod(result, ml);
-            if (!meth)
+            if (!meth) {
+                Py_DECREF(result);
                 return NULL;
+            }
             x = PyDict_SetItemString(result->tp_dict,
                                      ml->ml_name,
                                      meth);
@@ -2159,8 +2170,10 @@ converters_from_argtypes(PyObject *ob)
 
     nArgs = PyTuple_GET_SIZE(ob);
     converters = PyTuple_New(nArgs);
-    if (!converters)
+    if (!converters) {
+        Py_DECREF(ob);
         return NULL;
+    }
 
     /* I have to check if this is correct. Using c_char, which has a size
        of 1, will be assumed to be pushed as only one byte!

Modules/_ctypes/callproc.c

@@ -157,8 +157,10 @@ _ctypes_get_errobj(int **pspace)
             return NULL;
         memset(space, 0, sizeof(int) * 2);
         errobj = PyCapsule_New(space, CTYPES_CAPSULE_NAME_PYMEM, pymem_destructor);
-        if (errobj == NULL)
+        if (errobj == NULL) {
+            PyMem_Free(space);
             return NULL;
+        }
         if (-1 == PyDict_SetItem(dict, error_object_name,
                                  errobj)) {
             Py_DECREF(errobj);
@@ -1681,6 +1683,10 @@ POINTER(PyObject *self, PyObject *cls)
         if (result == NULL)
             return result;
         key = PyLong_FromVoidPtr(result);
+        if (key == NULL) {
+            Py_DECREF(result);
+            return NULL;
+        }
     } else if (PyType_Check(cls)) {
         typ = (PyTypeObject *)cls;
         buf = PyMem_Malloc(strlen(typ->tp_name) + 3 + 1);

Modules/_ctypes/cfield.c

@@ -1246,8 +1246,7 @@ U_set(void *ptr, PyObject *value, Py_ssize_t length)
                         "unicode string expected instead of %s instance",
                         value->ob_type->tp_name);
         return NULL;
-    } else
-        Py_INCREF(value);
+    }
 
     wstr = PyUnicode_AsUnicodeAndSize(value, &size);
     if (wstr == NULL)
@@ -1256,7 +1255,6 @@ U_set(void *ptr, PyObject *value, Py_ssize_t length)
         PyErr_Format(PyExc_ValueError,
                      "string too long (%zd, maximum length %zd)",
                      size, length);
-        Py_DECREF(value);
         return NULL;
     } else if (size < length-1)
         /* copy terminating NUL character if there is space */
@@ -1266,6 +1264,7 @@ U_set(void *ptr, PyObject *value, Py_ssize_t length)
         return NULL;
     }
 
+    Py_INCREF(value);
     return value;
 }
 
@@ -1292,9 +1291,7 @@ s_set(void *ptr, PyObject *value, Py_ssize_t length)
     char *data;
     Py_ssize_t size;
 
-    if(PyBytes_Check(value)) {
-        Py_INCREF(value);
-    } else {
+    if(!PyBytes_Check(value)) {
         PyErr_Format(PyExc_TypeError,
                      "expected bytes, %s found",
                      value->ob_type->tp_name);
@@ -1302,11 +1299,9 @@ s_set(void *ptr, PyObject *value, Py_ssize_t length)
     }
 
     data = PyBytes_AS_STRING(value);
-    if (!data)
-        return NULL;
     size = strlen(data); /* XXX Why not Py_SIZE(value)? */
     if (size < length) {
-        /* This will copy the leading NUL character
+        /* This will copy the terminating NUL character
          * if there is space for it.
          */
         ++size;
@@ -1314,13 +1309,11 @@ s_set(void *ptr, PyObject *value, Py_ssize_t length)
         PyErr_Format(PyExc_ValueError,
                      "bytes too long (%zd, maximum length %zd)",
                      size, length);
-        Py_DECREF(value);
         return NULL;
     }
     /* Also copy the terminating NUL character if there is space */
     memcpy((char *)ptr, data, size);
 
-    Py_DECREF(value);
     _RET(value);
 }
 
@@ -1428,9 +1421,7 @@ BSTR_set(void *ptr, PyObject *value, Py_ssize_t size)
     /* convert value into a PyUnicodeObject or NULL */
     if (Py_None == value) {
         value = NULL;
-    } else if (PyUnicode_Check(value)) {
-        Py_INCREF(value); /* for the descref below */
-    } else {
+    } else if (!PyUnicode_Check(value)) {
         PyErr_Format(PyExc_TypeError,
                         "unicode string expected instead of %s instance",
                         value->ob_type->tp_name);
@@ -1449,7 +1440,6 @@ BSTR_set(void *ptr, PyObject *value, Py_ssize_t size)
             return NULL;
         }
         bstr = SysAllocStringLen(wvalue, (unsigned)wsize);
-        Py_DECREF(value);
     } else
         bstr = NULL;