From 938223e8d1eabdd6a73531a8dd52407ef23f6375 Mon Sep 17 00:00:00 2001
From: "Miss Islington (bot)"
 <31488909+miss-islington@users.noreply.github.com>
Date: Tue, 4 Oct 2022 10:06:17 -0700
Subject: [PATCH] [3.9] gh-96577: Fixes buffer overrun in _msi module
 (GH-96633) (GH-96657)

gh-96577: Fixes buffer overrun in _msi module (GH-96633)
(cherry picked from commit 4114bcc9ef7595a07196bcecf9c7d6d39f57f64d)

Co-authored-by: Steve Dower <steve.dower@python.org>
---
 .../Windows/2022-09-07-00-11-33.gh-issue-96577.kV4K_1.rst     | 1 +
 PC/_msi.c                                                     | 4 ++--
 2 files changed, 3 insertions(+), 2 deletions(-)
 create mode 100644 Misc/NEWS.d/next/Windows/2022-09-07-00-11-33.gh-issue-96577.kV4K_1.rst

diff --git a/Misc/NEWS.d/next/Windows/2022-09-07-00-11-33.gh-issue-96577.kV4K_1.rst b/Misc/NEWS.d/next/Windows/2022-09-07-00-11-33.gh-issue-96577.kV4K_1.rst
new file mode 100644
index 00000000000..6025e5ce413
--- /dev/null
+++ b/Misc/NEWS.d/next/Windows/2022-09-07-00-11-33.gh-issue-96577.kV4K_1.rst
@@ -0,0 +1 @@
+Fixes a potential buffer overrun in :mod:`msilib`.
diff --git a/PC/_msi.c b/PC/_msi.c
index 913d3b85abb..fd68e1df07f 100644
--- a/PC/_msi.c
+++ b/PC/_msi.c
@@ -292,7 +292,7 @@ msierror(int status)
     int code;
     char buf[2000];
     char *res = buf;
-    DWORD size = sizeof(buf);
+    DWORD size = Py_ARRAY_LENGTH(buf);
     MSIHANDLE err = MsiGetLastErrorRecord();
 
     if (err == 0) {
@@ -386,7 +386,7 @@ record_getstring(msiobj* record, PyObject* args)
     unsigned int status;
     WCHAR buf[2000];
     WCHAR *res = buf;
-    DWORD size = sizeof(buf);
+    DWORD size = Py_ARRAY_LENGTH(buf);
     PyObject* string;
 
     if (!PyArg_ParseTuple(args, "I:GetString", &field))
-- 
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