[Cryptography-dev] v1.4: _openssl has no Cryptography_STATIC_CALLBACKS

[Robin Fishbein]

Hello,
 
I imagine this may have a trivial explanation, or perhaps indicate some quirk on my machine, but it looks as though some desired functionality isn’t available on my machine with version 1.4. I wanted to share this in case it indicates some wider issue of interest, and helps me learn a little about how cryptography works under the hood.
 
Windows 7, 64-bit, Python 3.5.1, and I believe OpenSSL 1.0.2. I use paramiko for SFTP, and when updating paramiko (on a whim) to 2.0.2 with Anaconda, it had me update cryptography as well, to version 1.4, or maybe it was 1.3 at first — either one experiences the issue. When attempting an SSH connect, I get a traceback ending with this:
 
File "C:\Users\...\AppData\Local\Continuum\Anaconda3\lib\site-packages\cryptography\hazmat\bindings\openssl\binding.py", line 73, in wrapper
    if lib.Cryptography_STATIC_CALLBACKS:
 
AttributeError: cffi library '_openssl' has no function, constant or global variable named 'Cryptography_STATIC_CALLBACKS'
 
When I manually carry out some of the imports in the source...
from cryptography.hazmat.bindings._openssl import ffi, lib
...and then look at what auto-complete shows for lib, I don’t see Cryptography_STATIC_CALLBACKS, which is consistent with the AttributeError. I don’t yet understand where to look for the source underneath the bootstrapped _openssl.*.pyd file.
 
The SSH connection and all subsequent functionality work fine with the latest versions of paramiko and cffi as long as I revert cryptography to 1.0.2.
 
-Robin Fishbein

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