[PATCH v4 1/3] comctl32: Fail on NULL string for edit control WM_GETTEXT message.

[Aida Jonikienė]

From: Aida Jonikienė

Zadig passes a fixed string length to WM_GETTEXT in one place regardless of the string:
https://github.com/pbatard/libwdi/blob/9b23b82a2dd1cbffc16d46c212f92c6bf8c0c...
(which causes a segfault with NULL strings on Wine but not on Windows).

This fixes an unrelated issue in https://bugs.winehq.org/show_bug.cgi?id=54750
(but not the main one).
---
 dlls/comctl32/edit.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/dlls/comctl32/edit.c b/dlls/comctl32/edit.c
index 4b950412617..b7fd50a75e9 100644
--- a/dlls/comctl32/edit.c
+++ b/dlls/comctl32/edit.c
@@ -3183,7 +3183,7 @@ static void EDIT_WM_ContextMenu(EDITSTATE *es, INT x, INT y)
  */
 static INT EDIT_WM_GetText(const EDITSTATE *es, INT count, LPWSTR dst)
 {
-    if (!count)
+    if (!count || !dst)
         return 0;

lstrcpynW(dst, es->text, count);