Fix #16759. Convert DWORD registry values using PyLong_FromUnsignedLong.

When converting REG_DWORD registry values into Python ints, the conversion
needs to be made from an *unsigned* long to match the DWORD type.

3 files changed, 23 insertions, 2 deletions

diff --git a/Lib/test/test_winreg.py b/Lib/test/test_winreg.py
index 68c12eb..a164d2f 100644
--- a/Lib/test/test_winreg.py
+++ b/Lib/test/test_winreg.py
@@ -335,6 +335,23 @@ class LocalWinregTests(BaseWinregTests):
         finally:
             DeleteKey(HKEY_CURRENT_USER, test_key_name)
 
+    def test_queryvalueex_return_value(self):
+        # Test for Issue #16759, return unsigned int from QueryValueEx.
+        # Reg2Py, which gets called by QueryValueEx, was returning a value
+        # generated by PyLong_FromLong. The implmentation now uses
+        # PyLong_FromUnsignedLong to match DWORD's size.
+        try:
+            with CreateKey(HKEY_CURRENT_USER, test_key_name) as ck:
+                self.assertNotEqual(ck.handle, 0)
+                test_val = 0x80000000
+                SetValueEx(ck, "test_name", None, REG_DWORD, test_val)
+                ret_val, ret_type = QueryValueEx(ck, "test_name")
+                self.assertEqual(ret_type, REG_DWORD)
+                self.assertEqual(ret_val, test_val)
+        finally:
+            DeleteKey(HKEY_CURRENT_USER, test_key_name)
+
+
 
 @unittest.skipUnless(REMOTE_NAME, "Skipping remote registry tests")
 class RemoteWinregTests(BaseWinregTests):
diff --git a/Misc/NEWS b/Misc/NEWS
index 08d3e36..bdf1094 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -10,6 +10,10 @@ What's New in Python 3.2.4
 Core and Builtins
 -----------------
 
+- Issue #16759: Support the full DWORD (unsigned long) range in Reg2Py
+  when retreiving a REG_DWORD value. This corrects functions like
+  winreg.QueryValueEx that may have been returning truncated values.
+
 - Issue #14420: Support the full DWORD (unsigned long) range in Py2Reg
   when passed a REG_DWORD value. Fixes OverflowError in winreg.SetValueEx.
 
diff --git a/PC/winreg.c b/PC/winreg.c
index 523ad17..e4b9307 100644
--- a/PC/winreg.c
+++ b/PC/winreg.c
@@ -900,9 +900,9 @@ Reg2Py(BYTE *retDataBuf, DWORD retDataSize, DWORD typ)
     switch (typ) {
         case REG_DWORD:
             if (retDataSize == 0)
-                obData = PyLong_FromLong(0);
+                obData = PyLong_FromUnsignedLong(0);
             else
-                obData = PyLong_FromLong(*(int *)retDataBuf);
+                obData = PyLong_FromUnsignedLong(*(int *)retDataBuf);
             break;
         case REG_SZ:
         case REG_EXPAND_SZ: