Handle hwnd and tbi when passing NULL

[András Kovács]

---
 dlls/user32/nonclient.c |   16 ++++++++++++++--
 1 files changed, 14 insertions(+), 2 deletions(-)

diff --git a/dlls/user32/nonclient.c b/dlls/user32/nonclient.c
index 708ed80..c127456 100644
--- a/dlls/user32/nonclient.c
+++ b/dlls/user32/nonclient.c
@@ -1628,13 +1628,25 @@ BOOL WINAPI GetTitleBarInfo(HWND hwnd, PTITLEBARINFO tbi) {
 
     TRACE("(%p %p)\n", hwnd, tbi);
 
+    dwStyle = GetWindowLongW(hwnd, GWL_STYLE);
+    dwExStyle = GetWindowLongW(hwnd, GWL_EXSTYLE);
+
+    if (dwStyle == 0) {
+        TRACE("Invalid hwnd.\n");
+        return FALSE;
+    }
+
+    if (!tbi) {
+        TRACE("tbi is NULL.\n");
+        SetLastError(ERROR_NOACCESS);
+        return FALSE;
+    }
+
     if(tbi->cbSize != sizeof(TITLEBARINFO)) {
         TRACE("Invalid TITLEBARINFO size: %d\n", tbi->cbSize);
         SetLastError(ERROR_INVALID_PARAMETER);
         return FALSE;
     }
-    dwStyle = GetWindowLongW(hwnd, GWL_STYLE);
-    dwExStyle = GetWindowLongW(hwnd, GWL_EXSTYLE);
     NC_GetInsideRect(hwnd, &tbi->rcTitleBar);
 
     GetWindowRect(hwnd, &wndRect);
-- 
1.6.0.4


--=-639lhw0GN4dt8etao3EY--