Fix for #1643874: When calling SysAllocString, create a PyCObject

which will eventually call SysFreeString to free the BSTR resource.

diff --git a/Misc/NEWS b/Misc/NEWS
index ad72b085107cf9dca2687e819a59f42f61d4a423..3fad86217a2b2cc1fc0a8013f2dad54ededbc7bd 100644 (file)
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -123,6 +123,8 @@ Core and builtins
 Library
 -------
 
+- Patch #1643874: memory leak in ctypes fixed.
+
 - Patch #1627441: close sockets properly in urllib2.
 
 - Bug #494589: make ntpath.expandvars behave according to its docstring.

diff --git a/Modules/_ctypes/cfield.c b/Modules/_ctypes/cfield.c
index ad83195276f94d5ccec3f954ce956b6a807dc2b7..799b457ed807bd1464bb2f24b8953e50c24f57ee 100644 (file)
--- a/Modules/_ctypes/cfield.c
+++ b/Modules/_ctypes/cfield.c
@@ -1432,10 +1432,19 @@ Z_get(void *ptr, unsigned size)
 #endif
 
 #ifdef MS_WIN32
+/* We cannot use SysFreeString as the PyCObject_FromVoidPtr
+   because of different calling convention
+*/
+static void _my_SysFreeString(void *p)
+{
+       SysFreeString((BSTR)p);
+}
+
 static PyObject *
 BSTR_set(void *ptr, PyObject *value, unsigned size)
 {
        BSTR bstr;
+       PyObject *result;
 
        /* convert value into a PyUnicodeObject or NULL */
        if (Py_None == value) {
@@ -1463,15 +1472,19 @@ BSTR_set(void *ptr, PyObject *value, unsigned size)
        } else
                bstr = NULL;
 
-       /* free the previous contents, if any */
-       if (*(BSTR *)ptr)
-               SysFreeString(*(BSTR *)ptr);
-       
-       /* and store it */
-       *(BSTR *)ptr = bstr;
+       if (bstr) {
+               result = PyCObject_FromVoidPtr((void *)bstr, _my_SysFreeString);
+               if (result == NULL) {
+                       SysFreeString(bstr);
+                       return NULL;
+               }
+       } else {
+               result = Py_None;
+               Py_INCREF(result);
+       }
 
-       /* We don't need to keep any other object */
-       _RET(value);
+       *(BSTR *)ptr = bstr;
+       return result;
 }