[Announce] Details on the GnuPG 1.4.15 and 2.0.22 release

[Werner Koch]

Hi!

Taylor asked me to forward this background info:

On Sat,  5 Oct 2013 10:56, wk at gnupg.org said:
> not yet been seen in the wild.  Details of the attack will eventually
> be published by its inventor.

  The zlib compression language that OpenPGP uses is powerful enough to
  express an OpenPGP compression quine -- that is, an OpenPGP compressed
  data packet that decompresses to itself -- causing infinite nesting of
  OpenPGP packets.  Source code to generate such a quine is at
  <http://mumble.net/~campbell/misc/pgp-quine/>.
  
  When fed the quine, older versions of GnuPG would blow the stack and
  crash.  GnuPG 1.4.15 and GnuPG 2.0.22 avoid this by setting a small
  constant bound on the depth of packet nesting.
  
  (This is similar to Tavis Ormandy's IPcomp compression quine, reported
  in CVE-2011-1547, which I didn't know about at the time I made the
  OpenPGP compression quine.  Both of us had read Russ Cox's article on
  zlib compression quines: <http://research.swtch.com/zip>.)



Salam-Shalom,

   Werner
  
-- 
Die Gedanken sind frei.  Ausnahmen regelt ein Bundesgesetz.


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