gh-83004: Harden msvcrt further

PC/msvcrtmodule.c

@@ -564,88 +564,81 @@ static struct PyMethodDef msvcrt_functions[] = {
  {NULL, NULL}
 };
 
-static void
-insertint(PyObject *d, char *name, int value)
-{
- PyObject *v = PyLong_FromLong((long) value);
- if (v == NULL) {
- /* Don't bother reporting this error */
- PyErr_Clear();
- }
- else {
- PyDict_SetItemString(d, name, v);
- Py_DECREF(v);
- }
-}
-
-static void
-insertptr(PyObject *d, char *name, void *value)
+static int
+insertptr(PyObject *mod, char *name, void *value)
 {
  PyObject *v = PyLong_FromVoidPtr(value);
  if (v == NULL) {
- /* Don't bother reporting this error */
- PyErr_Clear();
- }
- else {
- PyDict_SetItemString(d, name, v);
- Py_DECREF(v);
+ return -1;
  }
+ int rc = PyModule_AddObjectRef(mod, name, v);
+ Py_DECREF(v);
+ return rc;
 }
 
+#define INSERTINT(MOD, NAME, VAL) do { \
+ if (PyModule_AddIntConstant(MOD, NAME, VAL) < 0) { \
+ return -1; \
+ } \
+} while (0)
+
+#define INSERTPTR(MOD, NAME, PTR) do { \
+ if (insertptr(MOD, NAME, PTR) < 0) { \
+ return -1; \
+ } \
+} while (0)
+
+#define INSERTSTR(MOD, NAME, CONST) do { \
+ if (PyModule_AddStringConstant(MOD, NAME, CONST) < 0) { \
+ return -1; \
+ } \
+} while (0)
+
 static int
 exec_module(PyObject* m)
 {
- int st;
- PyObject *d = PyModule_GetDict(m); // Borrowed ref.
-
  /* constants for the locking() function's mode argument */
- insertint(d, "LK_LOCK", _LK_LOCK);
- insertint(d, "LK_NBLCK", _LK_NBLCK);
- insertint(d, "LK_NBRLCK", _LK_NBRLCK);
- insertint(d, "LK_RLCK", _LK_RLCK);
- insertint(d, "LK_UNLCK", _LK_UNLCK);
+ INSERTINT(m, "LK_LOCK", _LK_LOCK);
+ INSERTINT(m, "LK_NBLCK", _LK_NBLCK);
+ INSERTINT(m, "LK_NBRLCK", _LK_NBRLCK);
+ INSERTINT(m, "LK_RLCK", _LK_RLCK);
+ INSERTINT(m, "LK_UNLCK", _LK_UNLCK);
 #ifdef MS_WINDOWS_DESKTOP
- insertint(d, "SEM_FAILCRITICALERRORS", SEM_FAILCRITICALERRORS);
- insertint(d, "SEM_NOALIGNMENTFAULTEXCEPT", SEM_NOALIGNMENTFAULTEXCEPT);
- insertint(d, "SEM_NOGPFAULTERRORBOX", SEM_NOGPFAULTERRORBOX);
- insertint(d, "SEM_NOOPENFILEERRORBOX", SEM_NOOPENFILEERRORBOX);
+ INSERTINT(m, "SEM_FAILCRITICALERRORS", SEM_FAILCRITICALERRORS);
+ INSERTINT(m, "SEM_NOALIGNMENTFAULTEXCEPT", SEM_NOALIGNMENTFAULTEXCEPT);
+ INSERTINT(m, "SEM_NOGPFAULTERRORBOX", SEM_NOGPFAULTERRORBOX);
+ INSERTINT(m, "SEM_NOOPENFILEERRORBOX", SEM_NOOPENFILEERRORBOX);
 #endif
 #ifdef _DEBUG
- insertint(d, "CRT_WARN", _CRT_WARN);
- insertint(d, "CRT_ERROR", _CRT_ERROR);
- insertint(d, "CRT_ASSERT", _CRT_ASSERT);
- insertint(d, "CRTDBG_MODE_DEBUG", _CRTDBG_MODE_DEBUG);
- insertint(d, "CRTDBG_MODE_FILE", _CRTDBG_MODE_FILE);
- insertint(d, "CRTDBG_MODE_WNDW", _CRTDBG_MODE_WNDW);
- insertint(d, "CRTDBG_REPORT_MODE", _CRTDBG_REPORT_MODE);
- insertptr(d, "CRTDBG_FILE_STDERR", _CRTDBG_FILE_STDERR);
- insertptr(d, "CRTDBG_FILE_STDOUT", _CRTDBG_FILE_STDOUT);
- insertptr(d, "CRTDBG_REPORT_FILE", _CRTDBG_REPORT_FILE);
+ INSERTINT(m, "CRT_WARN", _CRT_WARN);
+ INSERTINT(m, "CRT_ERROR", _CRT_ERROR);
+ INSERTINT(m, "CRT_ASSERT", _CRT_ASSERT);
+ INSERTINT(m, "CRTDBG_MODE_DEBUG", _CRTDBG_MODE_DEBUG);
+ INSERTINT(m, "CRTDBG_MODE_FILE", _CRTDBG_MODE_FILE);
+ INSERTINT(m, "CRTDBG_MODE_WNDW", _CRTDBG_MODE_WNDW);
+ INSERTINT(m, "CRTDBG_REPORT_MODE", _CRTDBG_REPORT_MODE);
+ INSERTPTR(m, "CRTDBG_FILE_STDERR", _CRTDBG_FILE_STDERR);
+ INSERTPTR(m, "CRTDBG_FILE_STDOUT", _CRTDBG_FILE_STDOUT);
+ INSERTPTR(m, "CRTDBG_REPORT_FILE", _CRTDBG_REPORT_FILE);
 #endif
 
+#undef INSERTINT
+#undef INSERTPTR
+
  /* constants for the crt versions */
 #ifdef _VC_ASSEMBLY_PUBLICKEYTOKEN
- st = PyModule_AddStringConstant(m, "VC_ASSEMBLY_PUBLICKEYTOKEN",
- _VC_ASSEMBLY_PUBLICKEYTOKEN);
- if (st < 0) {
- return -1;
- }
+ INSERTSTR(m, "VC_ASSEMBLY_PUBLICKEYTOKEN", _VC_ASSEMBLY_PUBLICKEYTOKEN);
 #endif
 #ifdef _CRT_ASSEMBLY_VERSION
- st = PyModule_AddStringConstant(m, "CRT_ASSEMBLY_VERSION",
- _CRT_ASSEMBLY_VERSION);
- if (st < 0) {
- return -1;
- }
+ INSERTSTR(m, "CRT_ASSEMBLY_VERSION", _CRT_ASSEMBLY_VERSION);
 #endif
 #ifdef __LIBRARIES_ASSEMBLY_NAME_PREFIX
- st = PyModule_AddStringConstant(m, "LIBRARIES_ASSEMBLY_NAME_PREFIX",
- __LIBRARIES_ASSEMBLY_NAME_PREFIX);
- if (st < 0) {
- return -1;
- }
+ INSERTSTR(m, "LIBRARIES_ASSEMBLY_NAME_PREFIX",
+ __LIBRARIES_ASSEMBLY_NAME_PREFIX);
 #endif
 
+#undef INSERTSTR
+
  /* constants for the 2010 crt versions */
 #if defined(_VC_CRT_MAJOR_VERSION) && defined (_VC_CRT_MINOR_VERSION) && defined(_VC_CRT_BUILD_VERSION) && defined(_VC_CRT_RBUILD_VERSION)
  PyObject *version = PyUnicode_FromFormat("%d.%d.%d.%d",
@@ -656,14 +649,12 @@ exec_module(PyObject* m)
  if (version == NULL) {
  return -1;
  }
- st = PyModule_AddObjectRef(m, "CRT_ASSEMBLY_VERSION", version);
+ int st = PyModule_AddObjectRef(m, "CRT_ASSEMBLY_VERSION", version);
  Py_DECREF(version);
  if (st < 0) {
  return -1;
  }
 #endif
- /* make compiler warning quiet if st is unused */
- (void)st;
 
  return 0;
 }