Covert timing channel capacity of rate monotonic real-time scheduling algorithm in MLS systems.
Joon Son, Jim Alves-Foss · 2006
Joon Son and Jim Alves-FossCenter for Secure and Dependable SystemsUniversity of IdahoPOBOX 441008 Moscow, ID 83844-1008email: [son2320,jimaf]@uidaho.eduABSTRACTReal-time systems must satisfy timing constraints. In ourprevious work, we showed that a covert timing channelcannot be completely closed in some system configura-tions due to the timing constraints imposed by the Rate-Monotonic (RM) real-time scheduling algorithm. In thispaper, we construct a probabilistic model to measure twoquantities of a covert timing channel in RM based systems:channel capacity and quantity of specific information. Weshow how these two metrics can be calculated from ourprobabilistic model and why they are useful metrics in eval-uation of a covert (timing) channel.KEYWORDSCovert timing channel capacity, quantity of specific infor-mation, Rate-Monotonic scheduling.