Analysis of covert channels in disk arm based on operational semantics

Analyzed how covert channels produced in disk arm thoroughly,and found that it's very difficult to detect this kind of covert channels based on the methods of searching for system source code and system top level description at present.This paper proposed a method based on the operational semantics to study covert channels in disk arm.Considering process scheduling in disk arm as an abstract machine,it produced the inferential reasoning rule of elevator scheduling algorithm by the Plotkin's structured operational semantics,and obtained all the states of the abstract machine,as well as the states of dynamic-change history of the abstract machine according to these rules,all of which constituted the integral information conduction operational semantics model.Studied and analyzed the states tranforation and tranforation sequences on high and low security levels of the abstract machine,which could find covert channels in disk arm.