Trusts the libffi library inside of nixpkgs on Apple devices.
When Apple's fork of libffi is not detected, cffi assumes that libffi
uses a strategy for creating closures (i.e. callbacks) that is in
certain cases susceptible to a security exploit.
Based on some analysis I did:
https://groups.google.com/g/python-cffi/c/xU0Usa8dvhk
I believe that libffi already contains the code from Apple's fork that
is deemed safe to trust in cffi.
It uses a more sophisticated strategy for creating trampolines to
support closures that works on Apple Silicon, while the simple approach
that cffi falls back on does not, so this patch enables code that uses
closures on M1 Macs again.
Notably, pyOpenSSL is impacted and will be fixed by this, reported in
https://github.com/pyca/pyopenssl/issues/873
Note that libffi closures still will not work on signed apps without the
com.apple.security.cs.allow-unsigned-executable-memory entitlement while
https://github.com/libffi/libffi/pull/621
is still open (which I haven't tested but is my best guess from reading).
I am hopeful that all of these changes will be upstreamed back into cffi
and libffi, and that this comment provides enough breadcrumbs for future
maintainers to track and clean this up.
This seems like an upstream issue with the final release of python3.11.
Sadly, their gitlab is down right now, but I will pass the patch
upstream as soon as I can.
The build was falling back on impure paths because pkg-config was
missing. This caused a mismatch between headers picked up at
compile-time and run-time, specifically `ffi.h` from libffi and then one
in `/usr/include/ffi` on macOS.
The `buildPython*` function computes name from `pname` and `version`.
This change removes `name` attribute from all expressions in
`pkgs/development/python-modules`.
While at it, some other minor changes were made as well, such as
replacing `fetchurl` calls with `fetchPypi`.
