Re: Shared memory DoS's

From: Dick St.Peters (stpetersat_private)
Date: Thu Jul 15 1999 - 16:09:46 PDT

  • Next message: Nicolas V. Chernyy: "Re: Shared memory DoS's"

    Mike Perry writes:
    
    > So as it turns out that it is in fact possible to create a DoS condition by
    > requesting a truckload of shared mem, then triggering pagefaults in the entire
    > shared region.
    
    Mapped memory segments have been susceptible to this since at least
    the early days of VMS, which AFAIK was the first OS to implement
    mapped memory (VMS used the term "mapped section").  I ran into this
    by accident no later than 1982 while doing image processing on a VMS
    system.  My processes run at the lowest possible priority (equivalent
    to the highest possible niceness), would effectively shut down the
    system until they completed.
    
    VMS didn't have a lot of tools for analyzing what was happening, but a
    few experiments quickly showed the culprit was page faulting.  Image
    processing tends to step through memory sparsely.
    
    Sorry - I no longer have an exploit :)
    
    --
    Dick St.Peters, stpetersat_private
    Gatekeeper, NetHeaven, Saratoga Springs, NY
    Saratoga/Albany/Amsterdam/BoltonLanding/Cobleskill/Greenwich/
    GlensFalls/LakePlacid/NorthCreek/Plattsburgh/...
        Oldest Internet service based in the Adirondack-Albany region
    



    This archive was generated by hypermail 2b30 : Fri Apr 13 2001 - 14:52:34 PDT