[PATCH v3 2/3] user32: Correctly handle NULL string in WM_GETTEXT AtoW wrapper.

[Aida Jonikienė]

From: Aida Jonikienė

Spotted in WM_GETTEXT NULL string tests.
---
 dlls/user32/winproc.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/dlls/user32/winproc.c b/dlls/user32/winproc.c
index 5678e75b4e9..eb86572080d 100644
--- a/dlls/user32/winproc.c
+++ b/dlls/user32/winproc.c
@@ -275,6 +275,12 @@ LRESULT WINPROC_CallProcAtoW( winproc_callback_t callback, HWND hwnd, UINT msg,
             DWORD len = wParam * sizeof(WCHAR);

if (!(ptr = get_buffer( buffer, sizeof(buffer), len ))) break;
+            if (!str)
+            {
+                free_buffer( buffer, ptr );
+                ptr = NULL;
+            }
+
             ret = callback( hwnd, msg, wParam, (LPARAM)ptr, result, arg );
             if (wParam)
             {