[Bug 986147] Re: openssl 1.0.1-4ubuntu2 breaks a bunch of ciphers

[Thomas Bushnell, BSG]

Colin: I think I understand now much better; thanks.  The upgrade to
1.0.1 increased the number of ciphers, which in turn broke communication
with bad servers (of which there may be an important number). What a
thorny little knot of a problem. Short of fixing these bad servers
(which might be a hard and many-year problem), perhaps the only real
solution is to have our clients sort the ciphers by security preference,
and then attempt multiple connections. Obviously that's not a quick fix!

I see 1.0.1-4ubuntu5 has hit proposed, so I'll give that a try right
now.

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https://bugs.launchpad.net/bugs/986147

Title:
  openssl 1.0.1-4ubuntu2 breaks a bunch of ciphers

Status in “openssl” package in Ubuntu:
  Fix Committed
Status in “openssl” source package in Precise:
  Fix Committed

Bug description:
  in version 1.0.1-4ubuntu2, we see:

  
  openssl (1.0.1-4ubuntu2) precise-proposed; urgency=low

    * Backport more upstream patches to work around TLS 1.2 failures
      (LP #965371):
  ...
      - Truncate the number of ciphers sent in the client hello to 50.  Most
        broken servers should now work.
   ...

   -- Colin Watson <cjwatson at ubuntu.com>  Wed, 18 Apr 2012 15:03:56
  +0100

  We have a server which offers a very small number of ciphers. When
  this change hit, suddenly our hosts could no longer contact this
  server, getting the error:

  
  $ openssl s_client -connect HOSTNAME:9140 
  CONNECTED(00000003) 
  139736292189856:error:14077410:SSL routines:SSL23_GET_SERVER_HELLO:sslv3 alert handshake failure:s23_clnt.c:724: 

  The problem here was tracked down to a failure to find a matching
  cipher. If we specify -cipher RC4-SSH (the only one essentially which
  the server permits) or -ssl3, the connection succeeds.

  The problem is this truncation of the number of ciphers sent. RC4-SSH
  shows up at something like #74 on our list, so it is getting
  truncated. When we specify exactly the cipher to use, of course it
  works, and if we say -ssl3, then that also reduces the number which
  would be sent, and now RC4-SSH is in the top fifty again.

  This is a pretty disastrous change, in fact; it means that openssl
  basically now supports only fifty ciphers at a time, and then an
  essentially random and unpredictable set. Not only does this mean a
  loss of functionality, it could be a loss in security if clients get
  pushed to less secure ciphers because the more secure ones happened to
  be after number fifty in the list.

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