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From: Poul-Henning Kamp <phk@FreeBSD.ORG>
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Date: Tue, 21 Jul 1998 22:53:56 -0700 (PDT)
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To: cvs-committers@FreeBSD.ORG, cvs-all@FreeBSD.ORG, cvs-usrsbin@FreeBSD.ORG
Subject: cvs commit: src/usr.sbin/inetd inetd.c
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phk         1998/07/21 22:53:55 PDT

  Modified files:
    usr.sbin/inetd       inetd.c 
  Log:
  This may apply to all known versions of inetd.
  
  For a tcp/nowait connection, inetd invokes accept(2) for
  each pending connection; this call returns a file descriptor
  associated with the new connection.
  
  Twelve years ago, code was added to inetd to detect "failing
  servers".  The heuristic that identifies a failing server is
  one that has been invoked a large number of times over some
  specified interval (e.g., more than 128 ftp services started
  in 60 seconds may flag the ftp service as "failing").  These
  compile-time constants vary depending on vendor.
  
  The problem is that, when a failing server is detected, the
  code neglects to close the file descriptor returned by the
  accept(2).
  
  Security-Implications:
  I suppose someone with ample free time could orchestrate an
  attack buy pummeling services until the inetd process finally
  runs out of file descriptors thus rendering inetd useless to
  any new connections that require a new descriptor.
  
  PR:		7286
  Reviewed by:	phk
  Submitted by:	Jeff Forys <jeff@forys.cranbury.nj.us>
  
  Revision  Changes    Path
  1.35      +4 -1      src/usr.sbin/inetd/inetd.c

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