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diff --git a/destructive_interference.mdwn b/destructive_interference.mdwn new file mode 100644 index 00000000..1f468034 --- /dev/null +++ b/destructive_interference.mdwn @@ -0,0 +1,32 @@ +[[!meta copyright="Copyright © 2007, 2008 Free Software Foundation, Inc."]] + +[[!meta license="""[[!toggle id="license" text="GFDL 1.2+"]][[!toggleable +id="license" text="Permission is granted to copy, distribute and/or modify this +document under the terms of the GNU Free Documentation License, Version 1.2 or +any later version published by the Free Software Foundation; with no Invariant +Sections, no Front-Cover Texts, and no Back-Cover Texts. A copy of the license +is included in the section entitled +[[GNU Free Documentation License|/fdl]]."]]"""]] + +Interference can be destructive or non-destructive. When a [[principal]] +invokes an object (thereby requesting a service) and the implementation +carries out the principal's intent, the interference was non-destructive +in the sense that the interference was desired. + +In invoking the object, the principal may make itself vulnerable to +destructive interference. When a user runs Solitaire on Windows, +the Solitaire program is instantiated and given all of the user's +authority. The program may delete all of the users files after +publishing credit card and other sensitive information on the Internet. +This type of interference is undesirable, however, generally practically +unavoidable due to the way programs work on Windows (and [[Unix]], for that +matter). + +The problem is that the callee has induced negative consequence for caller +due to actions of the former. To not have to depend on another program (and +thereby not have to add it to its [[tcb]]), it is necessary that the +caller only make itself vulnerable to destructive inference in ways that +can be detected and from which it can recover. + +Mark Miller examines the idea of destructive interference in his PhD thesis +[Robust Composition: Towards a Unified Approach to Access Control and Concurrency Control](http://www.erights.org/talks/thesis/). |