user32: Check structure size in GetGUIThreadInfo.

dlls/user32/focus.c

@@ -160,6 +160,7 @@ static BOOL set_active_window( HWND hwnd, HWND *prev, BOOL mouse, BOOL focus )
     {
         GUITHREADINFO info;
 
+        info.cbSize = sizeof(info);
         GetGUIThreadInfo( GetCurrentThreadId(), &info );
         /* Do not change focus if the window is no more active */
         if (hwnd == info.hwndActive)

dlls/user32/message.c

@@ -2359,6 +2359,7 @@ static BOOL process_mouse_message( MSG *msg, UINT hw_id, ULONG_PTR extra_info, H
 
     /* find the window to dispatch this mouse message to */
 
+    info.cbSize = sizeof(info);
     GetGUIThreadInfo( GetCurrentThreadId(), &info );
     if (info.hwndCapture)
     {
@@ -4235,6 +4236,12 @@ BOOL WINAPI GetGUIThreadInfo( DWORD id, GUITHREADINFO *info )
 {
     BOOL ret;
 
+    if (info->cbSize != sizeof(*info))
+    {
+        SetLastError( ERROR_INVALID_PARAMETER );
+        return FALSE;
+    }
+
     SERVER_START_REQ( get_thread_input )
     {
         req->tid = id;

dlls/user32/painting.c

@@ -801,6 +801,7 @@ static HWND fix_caret(HWND hWnd, const RECT *scroll_rect, INT dx, INT dy,
     RECT rect, mapped_rcCaret;
     BOOL hide_caret = FALSE;
 
+    info.cbSize = sizeof(info);
     if (!GetGUIThreadInfo( GetCurrentThreadId(), &info )) return 0;
     if (!info.hwndCaret) return 0;
     

dlls/user32/tests/win.c

@@ -611,6 +611,22 @@ static DWORD CALLBACK enum_thread( void *arg )
     BOOL ret;
     MSG msg;
 
+    if (pGetGUIThreadInfo)
+    {
+        GUITHREADINFO info;
+        info.cbSize = sizeof(info);
+        ret = pGetGUIThreadInfo( GetCurrentThreadId(), &info );
+        ok( ret || broken(!ret), /* win9x */
+            "GetGUIThreadInfo failed without message queue\n" );
+        SetLastError( 0xdeadbeef );
+        info.cbSize = sizeof(info) + 1;
+        ret = pGetGUIThreadInfo( GetCurrentThreadId(), &info );
+        ok( !ret, "GetGUIThreadInfo succeeded with wrong size\n" );
+        ok( GetLastError() == ERROR_INVALID_PARAMETER ||
+            broken(GetLastError() == 0xdeadbeef), /* win9x */
+            "wrong error %u\n", GetLastError() );
+    }
+
     PeekMessage( &msg, 0, 0, 0, PM_NOREMOVE );  /* make sure we have a message queue */
 
     count = 0;

dlls/user32/win.c

@@ -1587,6 +1587,7 @@ static void WIN_SendDestroyMsg( HWND hwnd )
 {
     GUITHREADINFO info;
 
+    info.cbSize = sizeof(info);
     if (GetGUIThreadInfo( GetCurrentThreadId(), &info ))
     {
         if (hwnd == info.hwndCaret) DestroyCaret();

dlls/winex11.drv/event.c

@@ -497,6 +497,7 @@ static void set_focus( Display *display, HWND hwnd, Time time )
     TRACE( "setting foreground window to %p\n", hwnd );
     SetForegroundWindow( hwnd );
 
+    threadinfo.cbSize = sizeof(threadinfo);
     GetGUIThreadInfo(0, &threadinfo);
     focus = threadinfo.hwndFocus;
     if (!focus) focus = threadinfo.hwndActive;