Dynamic Protection

• Process may need to dynamically change access rights while executing (i.e. switch from one domain to another c.f. OS mode with access to privileged instructions) - Generally needed for OS procedures
• Use access matrix with domains as objects and enter rights to indicate domain switch can take place
• Another means of dynamically changing protection is to change access matrix itself : Owner : can add/remove any access right within the column applying to the owned object
  Copy : can copy rights marked with * within the column
  Transfer : can transfer rights marked with + within column
  Control : applies only to domains - A process in domain D2 can add or remove access rights within the row applying to D4

  
Figure: Access Matrix