ofz#43458 avoid OOM

Change-Id: Id0e1e985c446c147a219ba2f5157a41deae656a4
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/128193
Tested-by: Jenkins
Reviewed-by: Caolán McNamara <caolanm@redhat.com>

lotuswordpro/source/filter/lwpdrawobj.cxx

@@ -1047,6 +1047,8 @@ void LwpDrawTextBox::Read()
 
     // the 71 is the fixed length before text content in textbox record
     sal_Int16 TextLength = m_aObjHeader.nRecLen - 71;
+    if (TextLength < 0)
+        throw BadRead();
     m_aTextRec.pTextString = new sal_uInt8 [TextLength];
 
     m_pStream->ReadBytes(m_aTextRec.pTextString, TextLength);