Re: Diversity

From: Adam Shostack (adamat_private)
Date: Mon Jun 21 1999 - 08:35:32 PDT

  • Next message: Stephen Woods: "Re: Diversity"

    On Thu, Jun 17, 1999 at 08:02:27PM -0700, David wrote:
    
    | Diversity can certainly be thought about.  The open source model encourages
    | program development.  Many people writing differing versions of software.
    | Naturally this diversity means an exploit in one program is unlikely to be
    | found in another.
    
    This is not my experience.  Different people tend to make the same
    mistakes in different ways.  See, for example the variety of bugs that
    have happened when you combine web servers with NTFS (::$DATA,
    'file%20', 'file.').  Diversity doesn't help here.  (I know you
    focused on unix systems, but there was a large and diverse group who
    worked on the web servers that had these problems.)  Also, OS
    diversity doesn't always help.  The rlogin -froot bug occured in both
    AIX and linux.  (I believe it was the same person who wrote the code
    both times)  Lots of versions of dump/restore have had the same link
    management problems.
    
    | Encourage diversity.  No one operating system should dominate.  Only OS
    | zealots would differ with this view.
    
    Having a dominant local OS means you can hire an expert or two in that
    OS, rather than needing experts in three or four OSs, tracking of bug
    reports across each of them, etc.  Lots of costs associated with this.
    
    Adam
    
    
    --
    "It is seldom that liberty of any kind is lost all at once."
    					               -Hume
    



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