> On Feb 9, 2016, at 12:08 PM, Glyph Lefkowitz <[email protected]> wrote:
> 
> 
>> On Feb 8, 2016, at 10:56 PM, Amber Hawkie Brown <[email protected] 
>> <mailto:[email protected]>> wrote:
>> 
>> Hi everyone,
>> 
>> There's a known issue with Twisted + PyOpenSSL>=0.13 using OpenSSL version 
>> 1.0.2f. Please note, this only potentially affects you if:
>> 
>> - You use Windows or OS X -- Cryptography 1.2.2's wheels have a bundled 
>> 1.0.2f.
>> OR
>> - You use a Linux or FreeBSD distribution which has OpenSSL 1.0.2f. If you 
>> are using a released distribution of Ubuntu or Debian, you most likely have 
>> a *patched* (so, still secure) past version (like Ubuntu 15.10, which has a 
>> patched 1.0.2d). If you are using Fedora 23, you may have 1.0.2f. You can 
>> check by running "openssl version".
>> 
>> There is also an unrelated issue with CFFI that causes Cryptography 1.2 
>> wheels for Windows/OS X to cause CPython to crash on interpreter shutdown.
>> 
>> The current highest working Cryptography version that causes a test suite 
>> pass is 1.2.2 on Linux with OpenSSL versions other than 1.0.2f, 1.1.2 on 
>> Windows & OS X without an unreleased CFFI patch, and 1.2.1 once the CFFI 
>> patch is released. Our Windows and OS X builders have their Cryptography 
>> dependencies pinned to 1.1.2 until these problems are solved.
>> 
>> Please note, this doesn't mean your applications may or may not work in 
>> practice with OpenSSL 1.0.2f! It just means the test suite does not pass, so 
>> we can't be absolutely sure that 1.0.2f will not cause problems for you. The 
>> latest patched versions of OpenSSL are strongly recommended from a security 
>> standpoint.
>> 
>> The relevant issues are:
>> 
>> - Make tests pass on 1.0.2f (Twisted, 
>> https://twistedmatrix.com/trac/ticket/8189 
>> <https://twistedmatrix.com/trac/ticket/8189>)
>> - Crash during interpreter shutdown when using static callbacks (CFFI, 
>> https://bitbucket.org/cffi/cffi/issues/246/crash-during-interpreter-shutdown-when
>>  
>> <https://bitbucket.org/cffi/cffi/issues/246/crash-during-interpreter-shutdown-when>)
> 
> Thanks for the write-up, Amber.
> 
> The main consequence of this constellation of unfortunate facts is that it is 
> causing problems for Twisted development right now; the cffi issue may be 
> causing some issues with crashing at shutdown, but the crash occurs after 
> interpreter teardown so even programs that depend on "clean" shutdown (in the 
> sense that they need to do work at shutdown time) should be affected.  
> Systems that require a 0 exit-status from a daemon might be but hopefully 
> there aren't many of those.

One of these issues - the CFFI crash - 
https://bitbucket.org/cffi/cffi/issues/246/crash-during-interpreter-shutdown-when
 
<https://bitbucket.org/cffi/cffi/issues/246/crash-during-interpreter-shutdown-when>
 - is now fixed and released in cffi 1.5.2.  So we should start returning to 
normal shortly ;).

> All of these issues are under active investigation by the Cryptography and 
> CFFI teams, and the one thing that might be an issue in Twisted (the 1.0.2f 
> compatibility issue as Amber described above) has already gotten some 
> attention from Tristan Seligmann and there should be a fix available shortly.
> 
> In any case, I'm very happy that we are communicating better about arcane 
> issues like this :).  We'll try to send an update when they're all resolved.
> 
> -glyph
> 

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