tdf#154285 Check upper bound of arguments in SbRtl_CurDir

The LibreOffice Basic specification says CurDir should accept one
argument and in the case of a non-Windows system, ignore that argument
and simply return the current directory. So check that SbRtl_CurDir
accepts a maximum of two arguments.

Change-Id: Ia60114fac31aa4261c8251e26ef172a0370e6abc
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/163150
Reviewed-by: Mike Kaganski <mike.kaganski@collabora.com>
Tested-by: Jenkins

basic/source/runtime/methods.cxx

@@ -371,6 +371,9 @@ void SbRtl_CurDir(StarBASIC *, SbxArray & rPar, bool)
     // there's no possibility to detect the current one in a way that a virtual URL
     // could be delivered.
 
+    if (rPar.Count() > 2)
+       return StarBASIC::Error( ERRCODE_BASIC_BAD_ARGUMENT );
+
 #if defined(_WIN32)
     int nCurDir = 0;  // Current dir // JSM
     if (rPar.Count() == 2)