From 18820c1f534438a717efab37964ef7156694bb1d Mon Sep 17 00:00:00 2001
From: "Erlend E. Aasland" <erlend.aasland@protonmail.com>
Date: Sat, 8 Apr 2023 21:59:53 +0200
Subject: [PATCH 1/3] gh-83004: Harden msvcrt init

---
 PC/msvcrtmodule.c | 17 +++++++++++------
 1 file changed, 11 insertions(+), 6 deletions(-)

diff --git a/PC/msvcrtmodule.c b/PC/msvcrtmodule.c
index face4d03af9d4f..f06dc44cc4d1f6 100644
--- a/PC/msvcrtmodule.c
+++ b/PC/msvcrtmodule.c
@@ -609,7 +609,7 @@ PyMODINIT_FUNC
 PyInit_msvcrt(void)
 {
     int st;
-    PyObject *d, *version;
+    PyObject *d;
     PyObject *m = PyModule_Create(&msvcrtmodule);
     if (m == NULL)
         return NULL;
@@ -659,11 +659,16 @@ PyInit_msvcrt(void)
 
     /* 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)
-    version = PyUnicode_FromFormat("%d.%d.%d.%d", _VC_CRT_MAJOR_VERSION,
-                                                  _VC_CRT_MINOR_VERSION,
-                                                  _VC_CRT_BUILD_VERSION,
-                                                  _VC_CRT_RBUILD_VERSION);
-    st = PyModule_AddObject(m, "CRT_ASSEMBLY_VERSION", version);
+    PyObject *version = PyUnicode_FromFormat("%d.%d.%d.%d",
+                                             _VC_CRT_MAJOR_VERSION,
+                                             _VC_CRT_MINOR_VERSION,
+                                             _VC_CRT_BUILD_VERSION,
+                                             _VC_CRT_RBUILD_VERSION);
+    if (version == NULL) {
+        return NULL;
+    }
+    st = PyModule_AddObjectRef(m, "CRT_ASSEMBLY_VERSION", version);
+    Py_DECREF(version);
     if (st < 0) return NULL;
 #endif
     /* make compiler warning quiet if st is unused */

From 528221f5600a146024e71cdf97d42ea86603d4c6 Mon Sep 17 00:00:00 2001
From: "Erlend E. Aasland" <erlend.aasland@protonmail.com>
Date: Sun, 9 Apr 2023 00:27:11 +0200
Subject: [PATCH 2/3] Don't leak module object on error

---
 PC/msvcrtmodule.c | 33 ++++++++++++++++++++++-----------
 1 file changed, 22 insertions(+), 11 deletions(-)

diff --git a/PC/msvcrtmodule.c b/PC/msvcrtmodule.c
index f06dc44cc4d1f6..7ca452ed8f36bb 100644
--- a/PC/msvcrtmodule.c
+++ b/PC/msvcrtmodule.c
@@ -608,12 +608,11 @@ insertptr(PyObject *d, char *name, void *value)
 PyMODINIT_FUNC
 PyInit_msvcrt(void)
 {
-    int st;
-    PyObject *d;
     PyObject *m = PyModule_Create(&msvcrtmodule);
-    if (m == NULL)
+    if (m == NULL) {
         return NULL;
-    d = PyModule_GetDict(m);
+    }
+    PyObject *d = PyModule_GetDict(m);  // Borrowed ref.
 
     /* constants for the locking() function's mode argument */
     insertint(d, "LK_LOCK", _LK_LOCK);
@@ -642,19 +641,25 @@ PyInit_msvcrt(void)
 
     /* constants for the crt versions */
 #ifdef _VC_ASSEMBLY_PUBLICKEYTOKEN
-    st = PyModule_AddStringConstant(m, "VC_ASSEMBLY_PUBLICKEYTOKEN",
-                                    _VC_ASSEMBLY_PUBLICKEYTOKEN);
-    if (st < 0) return NULL;
+    int st = PyModule_AddStringConstant(m, "VC_ASSEMBLY_PUBLICKEYTOKEN",
+                                        _VC_ASSEMBLY_PUBLICKEYTOKEN);
+    if (st < 0) {
+        goto error;
+    }
 #endif
 #ifdef _CRT_ASSEMBLY_VERSION
     st = PyModule_AddStringConstant(m, "CRT_ASSEMBLY_VERSION",
                                     _CRT_ASSEMBLY_VERSION);
-    if (st < 0) return NULL;
+    if (st < 0) {
+        goto error;
+    }
 #endif
 #ifdef __LIBRARIES_ASSEMBLY_NAME_PREFIX
     st = PyModule_AddStringConstant(m, "LIBRARIES_ASSEMBLY_NAME_PREFIX",
                                     __LIBRARIES_ASSEMBLY_NAME_PREFIX);
-    if (st < 0) return NULL;
+    if (st < 0) {
+        goto error;
+    }
 #endif
 
     /* constants for the 2010 crt versions */
@@ -665,14 +670,20 @@ PyInit_msvcrt(void)
                                              _VC_CRT_BUILD_VERSION,
                                              _VC_CRT_RBUILD_VERSION);
     if (version == NULL) {
-        return NULL;
+        goto error;
     }
     st = PyModule_AddObjectRef(m, "CRT_ASSEMBLY_VERSION", version);
     Py_DECREF(version);
-    if (st < 0) return NULL;
+    if (st < 0) {
+        goto error;
+    }
 #endif
     /* make compiler warning quiet if st is unused */
     (void)st;
 
     return m;
+
+error:
+    Py_DECREF(m);
+    return NULL;
 }

From ad93c2a9dd01b1e17334722497ec2a83b05c7550 Mon Sep 17 00:00:00 2001
From: "Erlend E. Aasland" <erlend.aasland@protonmail.com>
Date: Sun, 9 Apr 2023 00:36:48 +0200
Subject: [PATCH 3/3] Revert moving 'st'

---
 PC/msvcrtmodule.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/PC/msvcrtmodule.c b/PC/msvcrtmodule.c
index 7ca452ed8f36bb..6e8b423c3839a9 100644
--- a/PC/msvcrtmodule.c
+++ b/PC/msvcrtmodule.c
@@ -608,6 +608,7 @@ insertptr(PyObject *d, char *name, void *value)
 PyMODINIT_FUNC
 PyInit_msvcrt(void)
 {
+    int st;
     PyObject *m = PyModule_Create(&msvcrtmodule);
     if (m == NULL) {
         return NULL;
@@ -641,8 +642,8 @@ PyInit_msvcrt(void)
 
     /* constants for the crt versions */
 #ifdef _VC_ASSEMBLY_PUBLICKEYTOKEN
-    int st = PyModule_AddStringConstant(m, "VC_ASSEMBLY_PUBLICKEYTOKEN",
-                                        _VC_ASSEMBLY_PUBLICKEYTOKEN);
+    st = PyModule_AddStringConstant(m, "VC_ASSEMBLY_PUBLICKEYTOKEN",
+                                    _VC_ASSEMBLY_PUBLICKEYTOKEN);
     if (st < 0) {
         goto error;
     }