Issue #24594: Validates persist parameter when opening MSI database

2 files changed, 19 insertions, 3 deletions

diff --git a/Misc/NEWS b/Misc/NEWS
index 86d499b..e4061d6 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -62,6 +62,8 @@ Core and Builtins
 Library
 -------
 
+- Issue #24594: Validates persist parameter when opening MSI database
+
 - Issue #28047: Fixed calculation of line length used for the base64 CTE
   in the new email policies.
 
diff --git a/PC/_msi.c b/PC/_msi.c
index 86a5943..9e7e36d 100644
--- a/PC/_msi.c
+++ b/PC/_msi.c
@@ -955,6 +955,17 @@ static PyTypeObject msidb_Type = {
         0,                      /*tp_is_gc*/
 };
 
+#define Py_NOT_PERSIST(x, flag)                        \
+    (x != (int)(flag) &&                      \
+    x != ((int)(flag) | MSIDBOPEN_PATCHFILE))
+
+#define Py_INVALID_PERSIST(x)                \
+    (Py_NOT_PERSIST(x, MSIDBOPEN_READONLY) &&  \
+    Py_NOT_PERSIST(x, MSIDBOPEN_TRANSACT) &&   \
+    Py_NOT_PERSIST(x, MSIDBOPEN_DIRECT) &&     \
+    Py_NOT_PERSIST(x, MSIDBOPEN_CREATE) &&     \
+    Py_NOT_PERSIST(x, MSIDBOPEN_CREATEDIRECT))
+
 static PyObject* msiopendb(PyObject *obj, PyObject *args)
 {
     int status;
@@ -962,11 +973,14 @@ static PyObject* msiopendb(PyObject *obj, PyObject *args)
     int persist;
     MSIHANDLE h;
     msiobj *result;
-
     if (!PyArg_ParseTuple(args, "si:MSIOpenDatabase", &path, &persist))
         return NULL;
-
-        status = MsiOpenDatabase(path, (LPCSTR)persist, &h);
+    /* We need to validate that persist is a valid MSIDBOPEN_* value. Otherwise,
+       MsiOpenDatabase may treat the value as a pointer, leading to unexpected
+       behavior. */
+    if (Py_INVALID_PERSIST(persist))
+        return msierror(ERROR_INVALID_PARAMETER);
+    status = MsiOpenDatabase(path, (LPCSTR)persist, &h);
     if (status != ERROR_SUCCESS)
         return msierror(status);