user32: Cope with null LPMENUITEMINFO in SetMenuItemInfo.

dlls/user32/menu.c

@@ -4795,8 +4795,8 @@ static BOOL MENU_NormalizeMenuItemInfoStruct( const MENUITEMINFOW *pmii_in,
                                               MENUITEMINFOW *pmii_out )
 {
     /* do we recognize the size? */
-    if( pmii_in->cbSize != sizeof( MENUITEMINFOW) &&
-            pmii_in->cbSize != sizeof( MENUITEMINFOW) - sizeof( pmii_in->hbmpItem)) {
+    if( !pmii_in || (pmii_in->cbSize != sizeof( MENUITEMINFOW) &&
+            pmii_in->cbSize != sizeof( MENUITEMINFOW) - sizeof( pmii_in->hbmpItem)) ) {
         SetLastError( ERROR_INVALID_PARAMETER);
         return FALSE;
     }

dlls/user32/tests/menu.c

@@ -948,6 +948,19 @@ static void test_menu_add_string( void )
         ok (!lstrcmpW( strbackW, expectedString ), "Menu text from Unicode version incorrect\n");
     }
 
+    /* Just try some invalid parameter tests */
+    SetLastError(0xdeadbeef);
+    rc = SetMenuItemInfoA( hmenu, 0, TRUE, NULL );
+    ret = GetLastError();
+    ok (!rc, "SetMenuItemInfoA succeeded unexpectedly\n");
+    ok (ret == ERROR_INVALID_PARAMETER, "Expected 87, got %d\n", ret);
+
+    SetLastError(0xdeadbeef);
+    rc = SetMenuItemInfoA( hmenu, 0, FALSE, NULL );
+    ret = GetLastError();
+    ok (!rc, "SetMenuItemInfoA succeeded unexpectedly\n");
+    ok (ret == ERROR_INVALID_PARAMETER, "Expected 87, got %d\n", ret);
+
     /* Just change ftype to string and see what text is stored */
     memset(&info, 0x00, sizeof(info));
     info.cbSize= sizeof(MENUITEMINFOA);